JP6837006B2 - Conductive thermal imaging receptor layer with receptor overcoat layer - Google Patents

Description

The present invention relates to a conductive thermal image receptor element for use in thermal printing.

(Cross-reference of related applications)
This application claims the interests of US Patent Provisional Application No. 62 / 155,906 filed May 1, 2015.

In recent years, thermal transfer systems have been developed to obtain printed matter from images generated by cameras or scanning devices. According to one method of obtaining such printed matter, first, an electronic image is color-separated by a color filter. Next, each color-separated image is converted into an electric signal. These signals are then transmitted to the thermal printing press. To obtain printed matter, a cyan, magenta or yellow dye donor element is placed facing the thermal image receiver element. Next, these two are inserted between the thermal printing head and the platen roller. Heat is applied from the back of the dye donor sheet using a line-type thermal print head. The thermal print head has many heating elements and is sequentially heated in response to one of the cyan, magenta or yellow signals. This process is then repeated in another color. In this way, a color hard copy corresponding to the original image visible on the screen is obtained.

Various methods have been proposed to obtain a thermal dye-receiving layer. Solvent coating of dye image receiving layer formulations is a common practice. However, the use of solvents to coat these formulations raises a variety of issues, including cost, environmental hazards and waste issues, as well as harmful manufacturing processes. Special precautions are needed to address these issues. Another approach is to hot melt extrude the dye image receiving layer formulation onto the support. Multiple layers can be extruded simultaneously when preparing the thermal imaging receptor element. While such methods are efficient in preparing useful thermal image receptor elements, the use of high temperatures in the extrusion process limits the types of materials that can be incorporated into the dye image receptor layer. Yet another approach is to use an aqueous coating formulation to prepare the dye image receiving layer. Such formulations typically include a water-soluble or water-dispersible polymer as a binder matrix.

Aqueous coating methods and formulations are desirable for the reasons already mentioned, but aqueous coated dye image receiving layers can present problems in a typical customer printing environment. In such a printing environment, when printing at high speed, it is required that the dye donor element and the thermal image receptor element smoothly separate from each other without sticking between the contact surfaces of the two elements. When such image printing is performed in a high humidity environment, the adhesion associated with the water-based coated dye image receptor layer may be particularly troublesome. Moreover, such thermal receptor elements often do not provide sufficient dye concentrations for thermally formed images. The water-based coated layer may also disintegrate when in contact with water. The industry has been proactive in addressing these issues with the various solutions presented in the literature.

Images obtained regardless of relative humidity when the thermal dye transfer element is stored or used, despite all known techniques for the various problems associated with the use of aqueous coated dye image receiving layer formulations. There remains a need to improve the resistance of such formulations (and the resulting dry layer) to changes in relative humidity so that they are stable and exhibit sufficient concentrations.

The present invention relates to a conductive heat-sensitive image receptor element having a water-based coatable dye-receptor layer containing a release agent, a cross-linking agent, a water-dispersible acrylic polymer, a water-dispersible polyester and a water-dispersible conductive polymer material. .. The present invention further comprises a release agent, a cross-linking agent, a water-dispersible acrylic polymer, a water-based coatable dye-receptor layer containing a water-dispersible polyester, and a receiver overcoat layer containing a water-dispersible conductive polymer material. It relates to a conductive heat-sensitive image receptor element having a layer). In addition, a surfactant may be added to the receptor overcoat layer, or an excess of surfactant may be added during the production of the water-dispersible acrylic polymer. The present invention also relates to a method for making this thermal image receptor element, as well as a method for using it to obtain a dye image by thermal transfer from a donor element.

It is a figure which shows the schematic appearance of two different thermal image receiving elements. FIG. 1A is a diagram showing an embodiment in which an aqueous coatable dye receiving layer (“DRL”) (layer (1)) having a conductive polymer material is the outermost (or uppermost) layer. It is a figure which shows the schematic appearance of two different thermal image receiving elements. FIG. 1B shows an embodiment in which the aqueous receptor overcoat layer (“ROC”) (layer (1a)) is the outermost (or top) layer and is above the aqueous coatable DRL (layer (1b)). It is a figure which shows. It is a table showing the test results of a heat-sensitive image receptor element (similar to that shown in FIG. 1A) containing a single layer of water-based coatable dye receptor layer, in which DRL is a water-dispersible acrylic polymer, water. Includes a dispersible polyester and a polymer matrix consisting essentially of a water dispersible conductive polymer material. It is a table showing the test results of a heat-sensitive image receptor element (similar to that shown in FIG. 1B) containing two layers of water-based coatable dye receptor layer, in which the two layers of DRL are water-dispersible acrylics. Includes a polymer binder matrix consisting essentially of a polymer, a water-dispersible polyester, and a receptor overcoat layer containing a water-dispersible conductive polymer material. It is a table which shows the result of various experiments which added the surfactant to the receptor overcoat layer of 2 layers of DRL. There was an undesired amount of misregistration when no surfactant was added. However, when the additional surfactant was added at about 2.5% by weight, the number of misplacements dropped to none or to an acceptable minimum. It is a table showing the results of various experiments in which a surfactant is added in excess of 1%, which is usually used for producing an acrylic polymer. Undesirable misregistration occurred when excess surfactant was not added. However, when the surfactant was added in an amount of about 2% by weight (or 1% excess) or more, the misregistration error was reduced to an acceptable level. It is a table which shows the result of using an antifoaming agent in various dispersions of an aqueous DRL formulation. As can be seen, the addition of an antifoaming agent to the aqueous dispersion can significantly reduce the foam height. It is a table showing the various defoamers tested in the dispersion of the aqueous DRL formulation and the effect of such defoamers on the actual foam height on the aqueous solution system after mixing. It is a table which shows in detail the filterability test result of various dispersions of an aqueous ROC formulation.

For example, a conductive thermal image receptor element may include a support and may have an electrically electrically conductive layer, including an outermost layer, on at least one surface of the support, the outermost layer being. A water-based coatable dye-receptor layer having a thickness in the range of 0.1 μm to 5 μm, the water-based dye-receptor layer comprises a water-dispersible stripping agent, a cross-linking agent, and a polymer binder matrix. 1) Water-dispersible acrylic polymer containing hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy or carboxylate group, chemically reacted or not chemically reacted, (2) Water-dispersible polyester having _{T g below 30 ° C.} , And (3) essentially consisting of a water-dispersible conductive polymer material, the water-dispersible acrylic polymer is present in an amount of at least 55% by weight of the total weight of the aqueous coatable dye receiving layer and is a water-dispersible polyester. It is present in a dry ratio of at least 1: 1.

The water-dispersible conductive polymer material has an amount in the range of 0.75% by weight to 2.0% by weight, or an amount in the range of 1.0% by weight to 1.25% by weight, or an amount in the aqueous dye receiving layer. It can be present in an amount in the range of 0.75% by weight to 1.5% by weight.

The conductive thermal image receptor element may, in addition, have any one or more of the following features: Water-dispersible acrylic polymers may contain carboxy or carboxylate groups that have been chemically or unreacted and are crosslinked via hydroxyl or carboxy groups to form aminoesters, urethanes, amides or urea groups. You may. The water-dispersible acrylic polymer is also a repeating unit derived from the following: (a) one or more ethylenes containing an unsaturated alkyl ester, a cycloalkyl ester or an aryl ester group having at least 4 carbon atoms. Repeats derived from sex-unsaturated polymerizable acrylates or methacrylates, (b) one or more carboxy-containing or sulfo-containing ethylenically unsaturated polymerizable acrylates or methacrylates, and (c) optionally styrene or styrene derivatives. Units may be included, the repeating unit of (a) corresponds to at least 20 mol% to 99 mol% or less of all repeating units, and the repeating unit of (b) corresponds to at least 1 mol% to 10 mol% or less. To do. Typically, the water-dispersible acrylic polymer is present in an amount of at least 55% to 90% by weight or less of the total weight of the aqueous coatable dye receiving layer. Alternatively, the water-dispersible acrylic polymer may be present in an amount of at least 60% to 90% by weight or less of the total weight of the dry image receiving layer. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in the polymer binder matrix is 1: 1 to 20: 1 or less, more specifically 4: 1 to 15: 1 or less.

Water-dispersible polyesters have at least -10 ° C. from 30 ° C. below T _g, the dye image-receiving layer itself has the following T _g 70 ° C. of at least 35 ° C.. The outermost layer of the thermal image receptor element has a dry thickness in the range of 0.8 μm to 2.0 μm, or 1.2 μm to 1.4 μm, or 0.1 μm to 5 μm.

Generally, the support is a polymer film or resin-coated cellulosic paper base, a microvoided polymer film, or the support is a cellulosic paper substrate or Includes synthetic paper substrate. The conductive thermal image receptor element of the present invention may be a single-sided thermal image receptor or a double-sided (duplex) thermal image receptor. The double-sided thermal image receptor element typically comprises the same or different aqueous coatable dye receptor layer on both opposing faces of the support. The aqueous coatable dye receiving layer may be placed directly on one or both of the opposing surfaces of the support. Alternatively, one or more of the conductive thermal image receptor elements of the present invention are between the support and the aqueous coatable dye receptor layer on one or both surfaces of the support. May include an intermediate layer of.

Here, referring to the water-dispersible release agent contained in the aqueous dye receiving layer, useful release agents include water-dispersible fluorine-based surfactants, silicone-based surfactants, modified silicone oils, polysiloxanes, modified polysiloxanes, and the like. And selected from the group consisting of crosslinked amino-modified polydimethylsiloxane. More specifically, the water-dispersible stripper may be polysilicone modified with amino side chains or end groups, at least 1% to 3% by weight based on the total weight of the dry image receiving layer. Exists in quantity. Alternatively, the water dispersible stripper may be a water dispersible polyoxyalkylene modified dimethylsiloxane graft copolyma having at least one alkylene oxide pendant chain having more than 45 alkoxide units. Typically, the water dispersible stripper is present in an amount of at least 1.0% to 5% by weight or less based on the total weight of the dry image receiving layer.

When referring to the cross-linking agent contained in the aqueous dye receiving layer, the cross-linking agent may be a carbodiimide or an aziridine derivative compound. Generally, the cross-linking agent consists of a group consisting of melamine formaldehyde resin, glycoluril formaldehyde resin, polycarboxylic acid and anhydride, polyamine, epihalohydrin, diepoxide, dialdehyde, diol, carboxylic acid halide, ketene, aziridine, carbodiimide, and isocyanate. It is an individual compound or a mixture of compounds of choice.

In another aspect of the present invention, the heat-sensitive image-receiving element of the conductivity, comprises a support, to one or both of the opposing surfaces of the support, drying the image receptive having the T _g 60 ° C. of at least 35 ° C. It may have a layer, which is the outermost layer of the heat-sensitive image acceptor element, has a dry thickness of at least 1 μm to 3 μm or less, and has a water-dispersible release agent, a cross-linking agent, and an aqueous dispersion. The polymer binder matrix comprises a conductive conductive polymer material and a polymer binder matrix, which are (1) chemically reacted or unreacted, water-dispersible acrylic polymer containing a carboxy or carboxylate group, and (2) at least 0. ° C. having to 20 ° C. below the T _g, essentially becomes a water-dispersible film-forming polyester, water-dispersible acrylic polymers, (a) having at least 4 carbon atoms, acrylic acid alkyl esters, cycloalkyl One or more ethylenically unsaturated polymerizable acrylates or methacrylates containing an ester or aryl ester group, (b) one or more carboxy-containing or carboxylate-containing ethylenically unsaturated polymerizable acrylates or methacrylates, and (c). The repeating unit of (a) corresponds to at least 20 mol% to 99 mol% or less of the total repeating unit, and the repeating unit of (b) includes the repeating unit derived from styrene or a styrene derivative, which is optional. The water-dispersible film-forming polyester has water-dispersible groups, and the water-dispersible acrylic polymer is at least 60% by weight of the total weight of the dry image-receiving layer. It is present in an amount of 90% by weight or less, and is present in the polymer binder matrix in a dry ratio of at least 4: 1 to 20: 1 or less with respect to the water-dispersible polyester.

Another modification of the present invention provides a heat-sensitive image receptor element comprising a support and having a dry image receptor layer as the outermost layer of the heat-sensitive image receptor element on at least one surface of the support, the dried image thereof. receiving layer is at least 25 ° C. from 70 ° C. below T _g, has the following dry thickness 5μm of at least 0.5 [mu] m, dried image-receiving layer, water-dispersible release agent, crosslinking agent, water-dispersible conductive Including a polymer material and a polymer binder matrix, the polymer binder matrix is (1) one or more water-dispersible acrylic polymers derived from one or more ethylenically unsaturated polymerizable monomas; and (2) 30 ° C. Essentially from water-dispersible polyesters with the following T _g , one or more water-dispersible acrylic polymers are present in an amount of at least 55% to 90% by weight based on the total weight of the dry image receiving layer. However, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at a drying ratio of at least 1: 1 to 20: 1 or less with respect to the water-dispersible polyester, and the water-dispersible release agent is dry. It is present in an amount of at least 0.5% by weight to 10% by weight or less based on the total weight of the image receiving layer.

Also disclosed is an imaging assembly comprising a thermal image receptor element according to any of the specifications described herein in which the thermal image receptor element is thermally associated with the heat sensitive donor element. Will be done.

Another aspect of the invention is a method for making the conductive thermal image receptor elements described herein. The method is the following step: (A) the step of applying the aqueous image receiving layer formulation to one or both of the opposing surfaces of the support, wherein the aqueous image receiving layer formulation is an aqueous dispersible release agent. Containing a cross-linking agent, a water-dispersible conductive polymer material, and a polymer composition, the polymer composition is (1) chemically reacted or unreacted, hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy or A water-dispersible acrylic polymer containing a carboxylate group, and (2) _{a water-dispersible polyester having a Tg of} 30 ° C. or lower, which is essentially composed of the water-dispersible acrylic polymer, is the whole dry image receiving layer obtained. Steps that are present in an amount of at least 55% by weight by weight and in the polymer binder matrix at a dry ratio of at least 1: 1 to 20: 1 or less relative to the water-dispersible polyester; and (B) aqueous image receiving layer. It comprises the step of drying the formulation to form a dry image receiving layer on one or both of the opposing surfaces of the support. According to this method, the aqueous image receiving layer formulation may be additionally heat treated at a temperature of at least 70 ° C. The method may further include applying the aqueous image receiving layer formulation to the support and drying it to obtain a dry image receiving layer of a predetermined pattern.

A related printing method is a transparent polymer film, one or more dye images, or both a transparent polymer film and one or more dye images, from a thermal donor element, dried conductive as described herein. Includes a step of image-like transfer to any of the image-receiving layers of the thermal image-receiving element of.

In one modification of the invention, the conductive heat-sensitive element may include a support and may have an electroconductive layer including an outermost layer on at least one surface of the support, the outermost layer being 1. A water-based coatable dye-receptor layer having a thickness in the range of 0 μm to 1.2 μm, the water-based dye-receptor layer contains a water-dispersible stripping agent, a cross-linking agent, and a polymer binder matrix. 1) Water-dispersible acrylic polymer containing hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy or carboxylate groups that has been chemically reacted or not; (2) Water-dispersible polyester having _{T g below 30 ° C.} And (3) essentially from a receptor overcoat layer containing a water-dispersible conductive polymer material, the water-dispersible acrylic polymer is in an amount of at least 55% by weight of the total weight of the aqueous coatable dye receiving layer. It is present and is present in a dry ratio of at least 1: 1 with respect to the water dispersible polyester.

The thickness of the receptor overcoat layer ranges from 0.1 μm to 0.62 μm, 0.10 μm to 0.8 μm, or 0.29 μm to 0.62 μm. Further, the water-dispersible conductive polymer material is contained in the receptor overcoat layer in an amount of 1.0% by weight or more, or 1.0% by weight to 3.0% by weight, or 1.0% by weight, based on the total dry weight of the receptor overcoat layer. It may be present in an amount in the range of 1.2% by weight to 3.0% by weight. In other words, the water-dispersible conductive polymer material may be present in the ^{receptor overcoat layer in excess of 10.76 mg / cm 3.}

Another aspect of the invention is the method of making the conductive thermal image receptor elements described herein. The method comprises the following steps: (A) applying the aqueous coatable dye receptor layer formulation to one or both of the opposing surfaces of the support, wherein the aqueous coatable dye receptor layer formulation is: The polymer binder composition comprises an aqueous dispersible stripping agent, a cross-linking agent, and a polymer binder, and the polymer composition is (1) chemically reacted or not chemically reacted, hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy or carboxylate. A water-dispersible acrylic polymer consisting essentially of a group-containing water-dispersible acrylic polymer and (2) a water-dispersible polyester having a Tg of 30 ° C. or lower, the water-dispersible acrylic polymer is at least 55 of the total weight of the resulting dry image-receiving layer. It is present in an amount by weight% and in the polymer binder matrix at a dry ratio of at least 1: 1 to 9.2: 1 or less, or at least 4: 1 to 20: 1 or less, relative to the water dispersible polyester. Steps; (C) Dry the aqueous image receptor layer formulation to form a dry image receptor layer on one or both of the opposing surfaces of the support; (D) Receptor overs comprising a conductive polymer material. The step of applying the coat layer onto at least one surface of the support coated with the aqueous coatable dye receiving layer; (E) the aqueous image receiving layer formulation is dried and one of the opposing surfaces of the support. Or it comprises the step of forming a dry image receiving layer on both.

According to such a method, the aqueous coatingable dye receiving layer formulation is heat treated at a temperature of at least 70 ° C. Further, when the dye receiving layer formulation capable of aqueous coating is applied to the support and dried, a dry image receiving layer having a predetermined pattern is obtained. The same aqueous coatable dye receiving layer formulation may be applied to both opposing surfaces of the support.

A feature of the present invention is that the outermost layer of the thermal image receptor element contains a conductive polymer material. The present invention provides that the water-dispersible conductive polymer material comprises poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonate). Alternatively, the water-dispersible conductive polymer material may essentially consist of poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonate) and protic solvents.

Another feature of the present invention is the inclusion of additional surfactant and / or dispersant in the receptor overcoat layer. That is, the present invention provides a conductive thermal image receptor element including an aqueous coatable dye receptor layer and a receptor overcoat layer, the receptor overcoat layer being a water-dispersible conductive polymer material and a surfactant. including. Typically, the surfactant is present in the receptor overcoat layer in an amount in the range of about 2.5% by weight, or 1-5% by weight. In addition to or instead of the surfactant, one or more dispersants may also be included in the receptor overcoat. Useful dispersants are random copolymers containing benzyl methacrylate and methacrylic acid, random tarpolimas of benzyl methacrylate, octadecyl methacrylate and methacrylic acid, and block copolymers or tarpolimas of acrylic acid. In certain modifications of the invention, the surfactant is present in the receptor overcoat in an amount of about 1-4% by weight, more specifically about 2%. One or more dispersants may also be present in the receptor overcoat with or without surfactant. One or more dispersants, during receptor overcoat, are approximately 0.5-6% by weight based on the total dry weight of the receptor overcoat layer (the sum of all dispersants contained in the receptor overcoat). ), More specifically, it exists in about 1% to 3% by weight.

According to the present invention, the conductive heat-sensitive image acceptor element may optionally include a support and have an electrically conductive layer including an outermost layer on at least one surface of the support. The outermost layer is an aqueous coatable dye receiving layer having a thickness in the range of 0.1 μm to 5 μm, and the aqueous dye receiving layer contains a water-dispersible release agent, a cross-linking agent, and a polymer binder matrix, and is a polymer binder. The matrix is (1) a water-dispersible acrylic polymer containing a hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy or carboxylate group that has been chemically reacted or has not been chemically reacted, and is used for preparing the acrylic polymer. Essentially from a water-dispersible acrylic polymer containing more than 1% excess surfactant; (2) a water-dispersible polyester having a Tg of 30 ° C. or lower; and (3) a water-dispersible conductive polymer material; The water-dispersible acrylic polymer is present in an amount of at least 55% by weight of the total weight of the aqueous coatable dye receiving layer and in a dry ratio of at least 1: 1 with respect to the water-dispersible polyester.

In one variant, the conductive thermal image acceptor element comprises a support and may have an electroconductive layer including an outermost layer on at least one surface of the support, the outermost layer being 0.1 μm. An aqueous coatable dye receiving layer having a thickness in the range of ~ 5 μm, the aqueous dye receiving layer contains a water-dispersible release agent, a cross-linking agent, and a polymer binder matrix, and the polymer binder matrix is (1) chemical. A water-dispersible acrylic polymer containing hydroxyl, phospho, phosphonate, sulfo, sulfonate, carboxy or carboxylate groups that has reacted or not chemically reacted and is in excess of 1% used to prepare the acrylic polymer. Essentially from a water-dispersible acrylic polymer containing a surfactant; (2) a water-dispersible polyester having a Tg of 30 ° C. or lower; and (3) a receptor overcoat layer containing a water-dispersible conductive polymer material. Thus, the water-dispersible acrylic polymer is present in an amount of at least 55% by weight of the total weight of the aqueous coatable dye receiving layer and in a dry ratio of at least 1: 1 with respect to the water-dispersible polyester. The excess surfactant may be present in an amount of about 1% to 5% by weight.

A further feature of the present invention is that one or more antifoaming agents are contained in the dye receiving layer of the thermal image receptor element. For example, one embodiment is a conductive thermal image receptor element having a dye receiving layer as described throughout the disclosure, wherein the dye receiving layer comprises a surfactant and a defoaming agent. Provides a thermal imaging receptor element. Antifoaming agents are DYNOL 607 by Air Products®, TEGO FOAMEX 800 by Evonik®, TEGO FOAMEX 805 by Evonik®, TEGO FOAMEX 825 by Evonik®, SILWET L-7200 by Trademarks) 62 Adaptive, Dow Corning® 62 Adaptive, XIAMETER AFE-1430, SILTECH C-4830 by Siltech, AIRASE 5300 by Air Products®, AIR Products 5300 by Air Products, and Air Products® It may be selected from the group consisting of AIRASE 5700 according to (registered trademark). Generally, the antifoaming agent is present in an amount of 0.01-0.32% by weight based on the total dry weight of the dye receiving layer.

In other words, the dye receiving layer containing the antifoaming agent is derived from the aqueous polymer emulsion. Such an aqueous polymer emulsion produces a foam height of 3.5 cm or less on the initial liquid surface after mixing the aqueous polymer emulsion at 2000 rpm for 2 minutes. More specifically, in the aqueous polymer emulsion, the aqueous polymer emulsion is mixed at 2000 rpm for 2 minutes, and after waiting for another 1 minute, a foam height of 0 cm is generated on the initial liquid surface.

The present invention will be described in more detail below with respect to particular embodiments thereof, but it will be appreciated that modifications and modifications may be made within the spirit and scope of the invention.

As used herein to define the compositions, formulations, and various components of the layers described herein, the singular forms "a," "an," and "the" are not specifically indicated. As long as it is intended to include one or more of the components (ie, including a plurality of referents).

The use of numbers within the various ranges specified herein is as if the word "about" precedes the minimum and maximum values within the range described, unless otherwise stated. , Is considered to be an approximation. In this way, values that vary slightly above and below the range described can be used to obtain substantially the same results as if the values were within the range. In addition, disclosure of these ranges is intended as a continuous range that includes any value between the minimum and maximum values.

Unless otherwise indicated, the terms "thermal image receptor element" and "receptor element" are used interchangeably to refer to features of the invention.

The term "double-sided" means that the opposing surfaces of the substrate (defined later) each have a dry image receiving layer (defined later) so that each surface is a thermal image (transparent polymer film or dye image) ) Can be formed, but in the method of the present invention, it is not always necessary to form a thermal image on both surfaces of the substrate. The "double-sided" element is also known as the "dual-sided" element.

The glass transition temperature (T _g ) is a differential scanning calorimetry (DSC) and known procedure, eg, when both the sample composition and the reference material are heated at a constant rate and maintained at the same temperature. It can be determined using the method of monitoring the difference in the input power. The difference in power input can be plotted as a function of temperature, and the temperature at which the gradient of the plot changes sharply is generally assigned as _{the T g of the sample polymer or dry image receiving layer composition.}

Unless otherwise indicated,% solids or% by weight is described relative to the total dry weight of a particular composition or a particular composition of a particular layer.

The term "heat-sensitive donor element" is used to refer to an element (as defined later) that can be used to thermally transfer a dye, ink, transparent film or metal. It is not necessary for each thermal donor element to transfer only the dye or ink.

The term "thermally related" is used to refer to two different elements arranged in a relationship that allows thermal transfer of a dye, metal or thin polymer film. Such a relationship generally requires the two elements to be physically brought into close contact with each other while they are being heated.

The term "water-based coated" is used to refer to a layer coated or coated from a water-based coating formulation.

The term "water-based coatable" is used to refer to a layer that has been applied or coated as a water-based coating formulation, but can then dry to become a dry layer.

Unless otherwise stated, the terms "polymer" and "resin" mean the same thing. Unless otherwise indicated, the term "acrylic polymer" includes not only homopolymers having the same repeating unit along the organic skeleton, but also copolimas having two or more different repeating units along the skeleton. Means.

The term "ethylenically unsaturated polymerizable monoma" refers to one or more ethylenically unsaturated types that can be polymerized to result in an organic skeleton chain of carbon atoms and, optionally, various side chains attached to the organic skeleton. Refers to an organic compound having a polymerizable group (vinyl group, etc.). The polymerization product of a particular ethylenically unsaturated polymerizable monoma is referred to as a "repetitive unit" within the organic backbone. The various repeating units in the water-dispersible acrylic polymer used in carrying out the present invention are dispersed in a random manner along the skeleton of a given polymer, and blocks of common repeating units are found. In some cases, it was not intentionally formed along the organic skeleton.

The terms "water-dispersible" and "water-dispersible" are used to describe any of the acrylic polymers, polyesters, release agents, or any other ingredients referred to herein. It means that these materials are generally dispersed in an aqueous medium during manufacturing or coating on a support. The term generally refers to the concept that a particular material is supplied and used in the form of an aqueous dispersion. Ingredients described as "water dispersible" cannot be dissolved in an aqueous medium and cannot be easily precipitated in an aqueous medium. These terms do not state that once coated and dried ingredients are redispersible in aqueous media. Rather, when the "water-dispersible" components dry on the support, they generally remain in close contact with water or aqueous solution.

The term "antistatic agent" means a water-dispersible conductive polymer material (as described in detail later).

[Thermal image receptor element]
Embodiments of the thermal image receptor element disclosed herein include an image receptor layer on one or both of the (opposing) surfaces of the support (discussed below) on the outermost side. In a single-layer DRL embodiment (FIG. 1A), the DRL is the outermost layer so that dye, transparent film or metal transfer takes place. In the embodiment shown in FIG. 1B, the outermost layer is a combination of two layers which are DRL / ROC. The ROC is at the top of the DRL. In a two-layer embodiment, both ROC and DRL accept the transfer of dye, transparent film or metal donor material. In both single-layer and two-layer embodiments, one or more additional layers (discussed below) can be placed between the dye image receiving layer and the support. Also, in both single-layer and two-layer embodiments, the DRL and ROC layers are formed as aqueous dispersions that are coated on one or both surfaces of the support. The components of such an aqueous dispersion for the DRL and ROC layers will be described below.

[Aqueous coatingable dye receiving layer]
A dry image-receptor layer (also referred to herein as an aqueous coatable dye-receptor layer, or an image-receptor layer, or simply DRL) is the best embodiment of a single-layer heat-sensitive image-receptor element. It is the outer layer, the second layer from the outermost in the embodiment of the two layers of thermosensitive image receptor elements (in this embodiment, the ROC is above the DRL). DRL Generally, at least 25 ° C. from 70 ° C. or less, or typically at least 35 ° C. from 70 ° C. or less, or at least 35 ° C. from 60 ° C. below _{T g.} Preferably, T _g is 30 ° C. or lower. T _g of the dried image-receiving layer, using a differential scanning calorimeter (DSC) was measured as described above, the following components: (1) water-dispersible acrylic polymer, (2) water-dispersible polyester, and (3 ) This is done by evaluating a dry image receiving layer formulation containing a polymer binder matrix containing one or more of the water-dispersible conductive polymer materials.

The aqueous coatingable dye receiving layer has a dry thickness of at least 0.1 μm to 5 μm or less, typically at least 0.5 μm to 3 μm or less. In certain embodiments, the aqueous coatable dye receiving layer has a dry thickness of 1.2 μm to 1.5 μm, whereas in other embodiments the DRL has a dry thickness of 0.7 μm to 1 μm. This dry thickness is an average value measured over at least 10 locations by a suitable scanning electron micrograph or other suitable means, and it is possible that there may be more points in the layer than the average dry thickness described. There is.

The water-based coatable dye receiving layer comprises (1) a water-dispersible acrylic polymer and (2) a polymer binder matrix essentially consisting of a water-dispersible polyester. In a single-layer DRL embodiment, a water-dispersible conductive polymer material (also referred to herein as a conductive polymer or antistatic agent) may be additionally included in the DRL.

[Polymer binder matrix component- (1) Water-dispersible acrylic polymer]
For one or more water-dispersible acrylic polymers in a polymer binder matrix of aqueous DRL, each of which has or has not chemically reacted, a hydroxyl, a phospho, a phosphonate, a sulfo, a sulfonate, a carboxy or a carboxylate group, particularly Contains carboxy or carboxylate groups that have chemically reacted or have not reacted. The term water-dispersible acrylic polymer includes styrene acrylic polymer. For example, water-dispersible acrylic polymers can be cross-linked via hydroxyl or carboxy groups (generally after applying the image receiving layer formulation to the support) to form aminoesters, urethanes, amides or urea groups. Can be done. If desired, a mixture of these water-dispersible acrylic polymers having the same or different reactive groups can be used.

Such water-dispersible acrylic polymers provide one or more ethylenically non-ethyleneic polymers that provide the desired properties of the resulting dry image-receptive layer: _Tg , crosslinkability, resistance to fading of the transferred dye, and thermal transferability. It can be designed from saturated polymerizable monomas. In general, useful water-dispersible acrylic polymers include repetitive units derived predominantly (more than 50 mol%) from one or more ethylenically unsaturated polymerizable monomas that provide the desired properties. The rest of the repeating units can be derived from different ethylenically unsaturated polymerizable monomas.

For example, the water-dispersible acrylic polymer is (a) one or more ethylenically unsaturated polymerizable acrylates or methacrylates containing an acyclic alkyl ester, cycloalkyl ester, or aryl ester group; (b) one or more carboxys. Includes repeating units derived from a combination of containing or sulfo-containing ethylenically unsaturated polymerizable acrylates or methacrylates, and (c) optionally styrene or styrene derivatives;

The acyclic alkyl ester, cycloalkyl ester, or aryl ester group may be substituted or unsubstituted and they can have up to 14 carbon atoms. Acyclic alkyl ester groups include linear and branched, substituted or unsubstituted alkyl groups (including aryl-substituted alkyl groups and aryloxy-substituted alkyl groups), from at least 1 to 22 or less. It can contain carbon atoms. Cycloalkyl ester groups generally contain at least 5 to 10 carbon atoms in the ring and are substituted or substituted cyclic ester groups (including alkyl substituted cyclic ester rings). Good. Useful aryl ester groups include phenyl ester and naphthyl ester groups, which may be unsubstituted or substituted with one or more groups on the aromatic ring.

(A) Typical examples of ethylenically unsaturated polymerizable acrylates or methacrylates include, but are not limited to, n-butyl acrylate, n-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, and acrylic. Benzyl acetate, benzyl methacrylate, 2-phenoxyethyl acrylate, stearyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl methacrylate, 2-chloroethyl acrylate, benzyl 2-propyl acrylate, n-butyl 2-bromoacrylate, Examples include phenoxyacrylate and phenoxymethacrylate. Examples of particularly useful (a) ethylenically unsaturated polymerizable acrylates and methacrylates include benzyl acrylate, benzyl methacrylate, t-butyl acrylate, and 2-phenoxyethyl acrylate.

Typical (b) hydroxy, phospho, carboxy or sulfo-containing ethylenically unsaturated polymerizable acrylates and methacrylates include, but are not limited to, acrylic acids, sodium salts, methacrylic acids, potassium salts, 2-acrylamide-2-methyl. Examples thereof include propanesulfonic acid, 2-acrylamide-2-methylpropanesulfonic acid, sodium salt, 2-sulfoethyl methacrylate, sodium salt, 3-sulfopropyl methacrylate, sodium salt, and similar compounds. Acrylic acids and methacrylic acids, or salts thereof, are particularly useful as the water-dispersible acrylic polymers now contain carboxy or carboxylate groups that have chemically reacted or have not reacted.

(C) The ethylenically unsaturated polymerizable monoma is not limited to these, but is limited to styrene, α-methylstyrene, 4-methylstyrene, 4-acetoxystyrene, 2-bromostyrene, α-bromostyrene, 2,4-dimethyl. Examples include styrene, 4-ethoxystyrene, 3-trifluoromethylstyrene, 4-vinylbenzoic acid, vinylbenzyl chloride, vinylbenzylacetate, and vinyltoluene. Styrene is particularly useful.

In these water-dispersible acrylic polymers, the repeating unit of (a) is generally at least 20 mol% to 99 mol% or less of all repeating units in the polymer, or more typically at least 30 mol% of all repeating units. Corresponds to 98 mol% or less.

The repeating unit of (b) generally corresponds to at least 1 mol% to 10 mol% or less, typically at least 2 mol% to 5 mol% or less of all repeating units in the polymer.

In some embodiments, the water-dispersible acrylic polymer comprises at least 1 mol% to 3 mol% or less of the repeating units derived from the repeating units of (a) based on all the repeating units in the polymer. It is desirable to have a small amount of pendant acid groups in it.

When the ethylenically polymerizable monomas of (c) are used to prepare water-dispersible acrylic polymers, the repeating units derived from these monomas are generally at least 30 mol% to 80 mol of the total repeating units in the polymer. It is present in an amount of% or less, or typically at least 50 mol% to 70 mol% or less.

The water-dispersible acrylic polymer used in the practice of the present invention can be prepared using readily available reactants and known addition polymerization conditions and free radical initiators. The preparation of some representative copolimas used in the present invention is shown later and is also shown in Tables I and II. For example, some useful water-dispersible acrylic polymers are available from Fujikura (Japan), DSM, and Eastman Kodak Company. Generally, the water-dispersible acrylic polymer is provided as an aqueous dispersion. Also, useful water-dispersible acrylic polymers generally have a number average molecular weight ( _Mn ) of at least 5,000 to 1,000,000 or less, as measured using size exclusion chromatography. Useful water-dispersible acrylic polymers include, but are not limited to, NeoCryl ™ A-6092, NeoCryl ™ XK-22, NeoCryl ™ 6092, and NeoCryl ™ 6015, Dow®. AVANSE MV-100, AVANSE 200, RHOPLEX ™ Acrylic Product Series, eg, Hoplex 585, HG-706, VSR-50, Z-Clean 1500, Lubrizol Carboset, and Carbotac Acrylic Product Series, Archema® ENCOR All acrylic emulsions and SNAP acrylic polymers include, for example, SNAP 720 and 728. In certain embodiments, a mixture of polymers is used (see below herein). Water-dispersible acrylic polymers are also sometimes referred to herein as "acrylic latex" or "acrylic polymer latex".

In some embodiments, the thermosensitive image acceptor element is (a) one or more ethylenically unsaturated polymerizable groups comprising an acyclic alkyl, cycloalkyl or aryl ester group having at least 4 carbon atoms. Water dispersibility containing repeating units derived from acrylates or methacrylates, (b) one or more carboxy-containing or sulfo-containing ethylenically unsaturated polymerizable acrylates or methacrylates, and (c) optionally styrene or styrene derivatives. Including the acrylic polymer, the repeating unit of (a) corresponds to at least 10 mol% to 99 mol% or less of all repeating units, and the repeating unit of (b) corresponds to at least 1 mol% to 10 mol% or less. ..

For example, the water-dispersible acrylic polymer in the dry image receiving layer is crosslinked via a hydroxyl or carboxy group using a suitable crosslinker (discussed below) to form an aminoester, urethane, amide or urea group. be able to.

One or more water-dispersible acrylic polymers are present in an amount of at least 55% by weight, typically at least 60% to 80% by weight or 90% by weight or less, based on the total weight of the dry image receiving layer. ..

[Polymer binder matrix component- (2) Water-dispersible polyester]
Each one or more water-dispersible polyester present in the polymer binder matrix, the 30 ° C. or less a T _g or _typically at least -10 ° C. from 30 ° C. or less, or even at least 0 ℃ from 20 ° C. or less It has a T _g of. Preferably, water-dispersible polyesters have the following T _g 30 ° C.. In general, water-dispersible polyesters are film-forming polymers that, when coated and dried, generally result in a uniform film. Such polyesters can contain several water dispersible groups such as sulfo, sulfonate, carboxyl or carboxylate groups to enhance water dispersibility. A mixture of these water-dispersible polyesters may be used together. Useful water-dispersible polyesters can be prepared by reacting with a suitable diol using a known diacid. In many embodiments, the diol is an aliphatic glycol and the diacid is an aromatic diacid, such as phthalic acid, isophthalic acid and terephthalic acid, in appropriate molar ratios. A mixture of diacids may be reacted with a mixture of glycols. One or both of the diacids or diols can contain suitable sulfo or carboxy groups to improve water dispersibility. Commercial sources of useful water-dispersible polyesters are described in the Examples below. Two useful water-dispersible polyesters are copolyesters of isophthalic acid and diethylene glycol, and copolimas formed from a mixture of isophthalic acid and terephthalic acid with ethylene glycol and neopentyl glycol. A typical polyester is Vylonal® MD-1480 available from Toyobo®. Other water-dispersible copolyesters include Vylonal® MD-1400, MD-1335, MD-1930, MD-1985, etc., also available from Toyobo®, and Eastman, also available from Eastman. AQ1350, AQ1395, AQ2350, and Eastek 1400.

Useful water-dispersible polyesters useful in the present invention can be obtained from several commercial sources such as Toyobo® (Japan) and Eastman Chemical Company, known starting materials and condensation polymerization conditions. Can also be easily prepared using.

In addition, one or more water-dispersible acrylic polymers are at least 1: 1 or typically at least 1: 1 to 6: 1 or less, or more suitable, with respect to the water-dispersible polyester in the polymer binder matrix. Is present in a dry ratio of at least 1.5: 1 to 4: 1 or less. Preferably, one or more water-dispersible acrylic polymers are present in the polymer binder matrix in a dry ratio of at least 1: 1 to 9.2: 1 or less relative to the water-dispersible polyester. In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 or at least 4: 1 to 20: 1 or less, or at least 1 with respect to the water-dispersible polyester. It exists in a dry ratio of 1 to 20: 1 or less, or at least 4: 1 to 15: 1 or less.

[Receptor overcoat layer that can be coated with water]
The receptor overcoat layer is the outermost layer in the embodiment of the bilayer thermal imaging receptor element. This layer does not exist in the embodiment of single layer DRL. The aqueous coatable receptor overcoat layer has a dry thickness of at least 0.1 μm to 5.0 μm or less, typically at least 0.2 μm to 1.0 μm or less. In certain embodiments, the aqueous coatable receptor overcoat layer has a dry thickness of 0.2 μm to 0.4 μm, whereas in other embodiments the ROC is 0.4 μm to 0.7 μm. Alternatively, it has a dry thickness of about 0.62 μm. According to the two-layer DRL / ROC embodiment (FIG. 1B), the combined thickness of the water-based coatable ROC and the water-based coatable DRL is about 0.8 μm to 2.0 μm, more specifically. It is 1.0 μm to 1.2 μm.

Aqueous-coatable receptor overcoat layer formulations are essentially from (1) water-dispersible acrylic polymers and (2) water-dispersible polyesters, which are described for DRL in all of the same points. Includes a polymer binder matrix that becomes. Therefore, with respect to ROC, the previous discussion of polymer binder matrix components is cited and incorporated herein. ROC is not only a water-dispersible conductive polymer material component (as described below), but also an additional surfactant and an optional addition, for example, a surfactant used for emulsifying a water-dispersible acrylic polymer. These stripping agents, one or more cross-linking agents, and any other additions described herein are additionally included. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 6: 1 or less, or typically at least 1.5: 1 to 5: 1 or less. Preferably, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 9.2: 1 or less. In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 with respect to the water-dispersible polyester, or typically at least 4: 1 to 20: 1 or less. , Or more preferably at least 1: 1 to 20: 1 or less, or even at least 4: 1 to 15: 1 or less.

[Water-dispersible conductive polymer material]
In a single-layer DRL embodiment, a water-dispersible conductive polymer material is present in the DRL. In a two-layer ROC / DRL embodiment, the water-dispersible conductive polymer material is added only to the ROC. Typical water-dispersible conductive polymer materials include thiophenes, such as poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonate) known as PEDOT or PEDT. Baytron® P and Clevios® P are commercially available PEDOT solutions that are 1.3% aqueous solutions of conjugated polymer PEDOT: PSS. PSS represents poly (styrene sulfonate).

The PEDOT: PSS complex is mixed with an alcohol such as diethylene glycol or any other polar solvent, thereby enhancing the conductivity of the PEDOT: PSS conjugated polymer. PEDOT: PSS is a positively charged conjugated polymer, yet optically transparent. The multilayer conductive heat-sensitive image receptor elements of the present invention can provide excellent electrical conductivity to efficiently and effectively dissipate static charges normally generated during the transfer of media and the image formation process. .. Such accumulation of static charges causes unwanted print defects such as white dropouts and wrinkles (creasing) on the actual printed image. The present invention eliminates the accumulation of static charges, thereby improving print quality and improving the stacking and handling of printed matter.

Another advantage of the present invention is that it can be used in all printing presses and can therefore be considered a general purpose printing press medium that can be used in many types of printing presses, including heat sensitive printing presses.

The water-dispersible conductive polymer material is based on the mass of the dry mass of each layer to which the conductive polymer is added in the DRL (single layer embodiment) or ROC (two layer embodiment). It may be present in an amount in the range of 5% to 3.0%, or more specifically 1.0% to 2.0% or 1.5% to 2.5%. As mentioned earlier, in certain embodiments, the water-dispersible conductive polymer material is added to the dye receptor layer, whereas in other embodiments, such material is added to the receptor overcoat layer. For example, referring to FIG. 1B, the conductive polymer material may or may not be added to the ROC layer. In practice, the ROC and DRL layers shown in FIG. 1B are coated at about the same time. As a result, the material in the ROC, including the conductive polymer material, leaches into the DRL. Specifically referring to the two-layer embodiment (FIG. 1B), the water-dispersible conductive polymer material is dried in the receptor overcoat layer in an amount of 1% or more by dry mass, or in place of it. It may be present in an amount of 1.4% or more by mass. In certain other embodiments, the conductive polymer material may also be present in the receptor overcoat in an amount ranging from 1.2% to 3%, or 1% to 3%. In yet another embodiment, the water-dispersible conductive polymer material is present in the ROC at a concentration of ^{10.76 mg / cm 3 or higher.}

FIG. 2 shows the case where the water-dispersible conductive polymer material is present in the aqueous coatable dye receiving layer of the single layer DRL embodiment (ie, none of the samples in FIG. 2 has an ROC layer). The composition of a typical polymer binder matrix is shown. C1 to C6 represent control samples, while E1 to E2 represent examples according to the present invention. In Control Examples C1 to C4, the conductive polymer material was added to the sublayer rather than the DRL. All four samples showed no buckling and wrinkles, but all but C1 produced image bleeding. Image bleeding was measured after 1 week under varying conditions: 35 ° C / 50% relative humidity; 40 ° C / 50% relative humidity; and 50 ° C / 50% relative humidity. Control sample C1 did not produce any wrinkles / wrinkles or image bleeding. However, it was necessary to significantly increase the thickness of the DRL to obtain such results. Control Examples C5 and C6 contained no conductive polymer material in the DRL and both test samples produced unwanted wrinkles and wrinkles. In Examples E1 and E2 of the present invention, the conductive polymer material was added to the DRL rather than the sublayer. Both E1 and E2 showed no wrinkles, wrinkles, or image bleeding. Nevertheless, the thickness of the DRL was maintained at 1.4 μm and the amount of conductive material required was significantly lower. Therefore, we do not want to add a conductive polymer material to the DRL without sacrificing the thinness of the DRL and without the need to add a significant amount of conductive material. And image blurring could be avoided. The surface resistance (“SER”) of each sample was also tested. During printing, it is advantageous to maintain a low surface resistivity to dissipate static electricity. As can be seen from FIG. 2, the addition of a conductive polymer material to the DRL helps to achieve these desired results.

FIG. 3 shows a typical case where the water-dispersible conductive polymer material is added to the receptor overcoat layer placed above the aqueous coatable dye receiving layer (as a two-layer ROC / DRL structure). The composition of the polymer binder matrix is shown. C8 to C13 represent control samples, while E3 to E9 represent examples according to the present invention. Similar to the test sample of FIG. 2, the sample shown in detail in FIG. 3 was observed for its effect on surface electrical resistance, wrinkles / wrinkles, and image quality. For all of the samples (C8-C13 and E3-E9), a conductive polymer material was added to the ROC. As can be seen from the samples C8 to C13 of FIG. 3, when the conductive material was added in an amount of 1.2% or less in dry mass, susceptibility to spot was observed. .. By increasing the amount of conductive polymer material in the ROC to more than 1.2%, the desired results were obtained, i.e., wrinkles, wrinkles, white spots or stains were less likely to occur.

The polymer polymer forms the main structure of both the dye receptor layer and the receptor overcoat layer, and the above-mentioned (1) water-dispersible acrylic polymer and (2) water-dispersible polyester and (3) water-dispersible conductivity. It is essentially free of polymers other than the sex polymer material. However, a smaller amount (typically less than 10% by weight of the total dry weight of each layer) of one or more other polymers or components may be added to the aqueous ROC and DRL dispersions to further desire. You can get the result. For example, such additional components may include conductive polymer materials (discussed above), as well as cross-linking agents, stripping agents, additional surfactants, and dispersants (discussed in more detail later).

[Other components-water-dispersible release agent]
In some embodiments, the aqueous coatable dye receptor layer and / or receptor overcoat layer is located between the thermal donor element and the thermal image receptor element of the invention during thermal imaging. It contains one or more water-dispersible release agents capable of reducing the stickiness that occurs. These compounds are generally not water-soluble, but water-dispersible such that they are uniformly dispersed in the aqueous image-receptive layer formulation (described above). The stripper can also help to form a uniform film within the dry image receiving layer during compounding and drying. These compounds may be polymeric or non-polymeric, but are generally polymeric. Such compounds are generally not redispersible once coated in an aqueous coatable dye receiving layer and dried.

Useful water-dispersible release agents include, but are not limited to, water-dispersible fluorosurfactants, silicone-based surfactants, and modified silicone oils (epoxy-modified, carboxy-modified, amino-modified, alcohol-modified, fluorine-modified, alkyl. Arylalkyl modifications, and others known in the art), as well as polysiloxanes. As a useful modified polysiloxane, it has more than 45 alkoxide units, as described in US Pat. No. 5,356,859 (Lum et al.), Which is incorporated herein by reference. Included are water-dispersible polyoxyalkylene-modified dimethylsiloxane grafted copolimas with at least one alkylene oxide pendant chain. Other useful stripping agents include crosslinked amino-modified polydimethylsiloxane, which can be supplied as an emulsion under the trade name Silkech® from Silicon Corporation. Some useful commercial products of this type are described in later examples.

A useful amount of one or more water dispersible strippers in the dry image receiving layer is generally at least 0.5% to 10% by weight or less, or typically, based on the total weight of the dry image receiving layer. At least 1% by weight to 5% by weight or less. The amount of water-dispersible stripper refers to the amount of the compound, not the amount of formulation or emulsion that can supply the compound.

The aqueous coatable dye receptor layer and receptor overcoat layer can also include residual cross-linking agents. Most of the cross-linking agents used in the image receptor layer formulation react during the preparation of the thermal image receptor element, but some may remain in the aqueous coatable dye receptor layer. Useful cross-linking agents will be described later.

[Other components-crosslinking agent]
A useful cross-linking agent that can be included in the aqueous image receptor layer formulation and / or the aqueous coatable receptor overcoat layer reacts with specific reactive groups on the water-dispersible acrylic polymer incorporated in the polymer binder matrix. Selected for ease of use. For example, in the case of reactive carboxyl and carboxylate groups, useful cross-linking agents are carbodiimides and aziridines.

One or more cross-linking agents are essentially contained in either or both of the aqueous image receptor layer formulation and the aqueous receptor overcoat layer formulation with the reactive groups in the water dispersible acrylic polymer in the formulation. Can be present in an amount having a molar ratio of 1: 1 or less. Generally, useful cross-linking agents include, but are not limited to, organic compounds such as melamine formaldehyde resins, glycol urylformaldehyde resins, polycarboxylic acids and anhydrides, polyamines, epihalohydrins, diepoxides, dialdehydes, diols, carboxylic acid halides , Ketene, aziridine, carbodiimide, isocyanate, and mixtures thereof.

The water-based coatable ROC and the water-based coatable DRL are the following additional additions, namely plasticizers, defoamers, coating aids, charge control agents known in the art for water-based coating formulations, respectively. , Thickener or viscosity modifier, anti-adhesive agent, UV absorber, fusion aid, matte beads (organic matte particles, etc.), antioxidant, stabilizer, and one or more fillers It may be contained. These optional additions can be given in known amounts, including any amount in the range of 3% -10% based on total dry layer weight.

[Additional excess surfactant added to DRL and ROC]
The receptor overcoat layer contains a polymer binder matrix consisting essentially of (1) water-dispersible acrylic polymer and (2) water-dispersible polyester and (3) water-dispersible conductive polymer material. The ROC layer may further contain one or more release agents, one or more crosslinkers, one or more defoamers, and one or more surfactants or emulsifiers. In certain preferred embodiments, an amount of surfactant is added to the aqueous ROC dispersion. That is, the detergent is added to the ROC dispersion after the acrylic polymer has already been formed, which is added to the amount of detergent used as an emulsifier in the production and suspension of the acrylic polymer. Therefore, such additional surfactants may be referred to herein as "additional surfactants". Those skilled in the art will appreciate that surfactants / emulsifiers are required to produce water-dispersible acrylic polymers.

In certain other embodiments, instead of adding an "additional surfactant" after the production of the water-dispersible acrylic polymer, an "excess surfactant" is added at the time of making the acrylic polymer. This excess surfactant is a surplus amount of surfactant that is more than necessary for actually producing the acrylic polymer, and is added at the time when the acrylic polymer is actually produced. Generally, a 1% amount of surfactant is required for the production of acrylic polymers. Thus, the "excess surfactant" is an amount of surfactant in excess of 1% used to make the acrylic polymer. For example, FIG. 5 shows a sample in which "excess surfactant" (> 1%) was added to the acrylic polymer composition and no "additional surfactant" was added to the ROC layer. It has been shown that acceptable results are obtained when 2-4% by weight of surfactant (1-3% excess surfactant) is added during the formulation of the acrylic polymer latex. In reference to FIG. 5, various types of acrylic polymers were tested by adding an excess of surfactant during the formulation of such acrylic polymers. The acrylic polymers tested were formulated with specific monomas in various weight ratios. FIG. 5 lists this ratio as group (c) / group (a) / group (b), where the monoma of group (c) is a styrene or styrene derivative and the monoma of group (a). Is an ethylenically unsaturated polymerizable acrylate or methacrylate containing an acyclic alkyl, cycloalkyl or aryl ester group having at least 4 carbon atoms, and the monoma of group (b) is a carboxy-containing or sulfo-containing ethylene. It is a sex unsaturated polymerizable acrylate or methacrylate. Except for the composition of the acrylic polymer and the amount of excess surfactant added, all of the samples consisted of the same amount of the same ingredients.

However, we consider making acrylic polymers with "normal", i.e., customarily required amounts of surfactant, and then adding "additional surfactant" to the ROC. Judged to be much better. This resulted in good results (less misregistration and less surfactant used). Reference to FIG. 4, when an "additional" surfactant is added to the ROC and not as an "excess surfactant" in the production of the water-dispersible acrylic polymer, the desired registration accuracy (registration). Only about 2.5% by weight of surfactant was required to achieve accuracy). From FIG. 4, it is clearly shown in Samples C1-C9 that no additional surfactant was added to the ROC. Print quality was not ideal for all of these samples due to misregistration. In Samples E1-E7, various types of additional surfactants were added in an amount of 2.5% by weight based on the total weight of the dry image receiving layer. For each of Examples E1 to E7, misregistration was reduced or eliminated altogether, and print quality became acceptable.

Useful surfactants are anionic or nonionic surfactants. Useful anionic surfactants include, but are not limited to: Rhodocal® A-246 (sodium C14-C16 sulfonate), Rhodapex® CO-436 (12-16% ethanol), 40 solids%); DOWNFAX 2A1 (alkyldiphenyloxide disulfonate), SDBS (sodium dodecylbenzene sulfonate) and ADS (sodium dodecyl sulfate). Useful nonionic surfactants include, but are not limited to, Olin-10G ™ (P-isononylphenoxypoly (glycidol)) or SILWET L-7230 (copolyma of silicone, ethylene oxide and propylene oxide). The amount of "excess" or "additional" surfactant added to the formulation is in the range of 1% to 5% by weight, or 2% to 5% by weight, or 3% to 4% by weight. Up to. In certain embodiments, the additional surfactant is about 2.5% by weight, or 1% to 3% by weight, or 2% to 2.5% by weight, or 2% to 3% by weight. Is added to the formulation.

By adding a surfactant to the ROC, we were able to reduce the number of misplacements. Misplacement is likely to occur at the end of the donor's ribbon spool, so we see that the last portion of the donor spool's printed matter (eg, the donor spool is typically about 250 sheets) If printed matter is to be printed, the last 50 sheets) were tested and analyzed to determine visual registration and registration accuracy. As will be appreciated by those skilled in the art, misplacement will result in poor print quality due to unclear lines, edges or boundaries that are not sharp. Moreover, misregistration causes the edges or boundaries to be inaccurately colored due to the inaccurate overlap of the various colors of the donor element that are transcribed into the acceptor element. For example, when the desired color is green, blue and yellow pigments are transferred to the receptor elements on top of each other. Misregistration can cause the edges or boundaries of printed matter to appear either yellow or blue instead of green because the blue and yellow pigments used to achieve green did not completely overlap.

[Other ingredients-antifoaming agent]
Due to the aqueous dispersion system carrying surfactants in the form of emulsifiers, surfactants, dispersants, etc., bubbles are easily generated during the preparation of the dispersion and during any subsequent coating application step. Foaming occurs especially when dispersions such as those discussed above undergo high shear steps. High shear steps include high speed agitation at about 1000 rpm (rotation / minute) and above, or high speed coating application at about 150 mpm (meter / minute) and above. During the high shear process, an undesired amount of foam is generated, which usually causes coating defects, unwanted compositional fluctuations, and annoying overflows, among other undesired effects. Moreover, excessive foaming requires frequent replacement of the coating equipment filter from one time. To address these issues, it is advantageous to incorporate an appropriate amount of one or more defoamers into the aqueous dispersion for the ROC and DRL layers. The present inventors have found that when a specific antifoaming agent is added in a specific amount, the foaming action of the aqueous DRL dispersion subjected to the high shearing step is effectively suppressed and controlled. The antifoaming agents described herein are generally water dispersible and have varying degrees of hydrophilic / hydrophobic balance. In addition, they typically (if not always) organic granules (eg, amides, waxes, liquid hydrocarbons, etc.) and / or inorganic granules (eg, fumed silica, etc.). Colloidal silica, etc.) are also incorporated with varying degrees of hydrophilic / hydrophilic balance. Useful defoamers include compounds with a high silicone content, such as structured siloxane defoamers, polyorganosiloxanes, resinous siloxane compounds, and polyethersiloxane copolymas. Useful defoaming agents include, but are not limited to, commercially available defoaming agents listed in FIG.

FIG. 7 is a table showing how different types of defoamers at different concentrations affect the foam height on the initial liquid level after the aqueous dispersion is subjected to a high shear process. The sample dispersions were each mixed at high speed for 2 minutes at 2000 rpm. Foam height measurements were taken immediately after the end of the mixing process (“0 minutes after mixing for 2 minutes”), 1 minute after the end of the mixing process, and 2 minutes after the end of the mixing process. As shown in FIG. 7, the control dispersion sample C1 did not contain an antifoaming agent, and as expected, the foam height on the initial liquid level was one of the highest levels observed in any sample. there were. Moreover, the foam remained at a level of about 5.1 cm above the initial liquid level after a waiting time of 2 minutes following the end of the high shear agitation step. The dispersion samples F1 to F17 each contained various amounts of antifoaming agent, but none of these dispersion samples effectively reduced the foam level after the high shear stirring step. On the other hand, the dispersion samples E10 to E30 were found to be more effective in lowering the foam level after the high shear stirring step. From the results of FIG. 7, it can be seen that certain types of defoamers effectively reduce foam levels after high shear steps, whereas other types of defoamers do not effectively reduce foam levels. Prove. Except for the type of antifoaming agent, the diluent used for the antifoaming agent, and the amount of antifoaming agent used, the DRL dispersion samples listed in FIG. 7 all have the same components, ie, water dispersibility. Includes acrylic polymer, water-dispersible polyester, release agent, cross-linking agent, and surfactant.

Similarly, FIG. 6 is a table showing how different types of antifoaming agents at different concentrations affect the foam height on the initial liquid level of some aqueous DRL dispersions. All of the dispersion samples E1 to E12 and C13 to C14 are aqueous DRL dispersions containing the same cross-linking agent, release agent, water-dispersible polyester, and water-dispersible acrylic polymer. For each of the dispersion samples listed in FIG. 6, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester present is approximately 9: 1, and the water-dispersible acrylic polymer is in the group of about 3% by weight ( b) consisted of the monomer, ie, a carboxy-containing or sulfo-containing ethylenically unsaturated polymerizable acrylate or methacrylate. The two control dispersion samples (C13 and C14) did not contain an antifoaming agent. As expected, the foam heights of the two control samples were much higher than those of the representative samples (E1 to E12), all containing certain types of antifoaming agents. Samples E7 to E12 showed extremely desirable results, respectively, as the bubbles were completely reduced only 2 minutes after mixing. As shown in FIGS. 6 and 7, the antifoaming agent was added to the DRL in an amount in the range of 0.04% by weight or more, or 0.04 to 0.32% by weight, or 0.16 to 0.32% by weight. It is advantageous to add in an amount within the range.

Some embodiments of the aqueous DRL dispersion of FIG. 6 also include at least one surfactant and / or dispersant (except Example C13, which contains no surfactant or dispersant). The diffusing agent, also known as a dispersant, is typically a material that strongly adsorbs onto the pigment particles. For optimum performance, the pigment particles must act independently of each other and thus remain well dispersed throughout manufacturing, storage, coating and film formation. In order to realize these advantageous properties, certain embodiments of the present invention have a DRL that comprises one or more surfactants combined with one or more dispersants. One or more surfactants may be present in an amount of up to approximately 10% by weight, or more specifically 1-6% by weight, based on the total dry weight of the DRL. Similarly, one or more dispersants may be present in an amount of up to approximately 10% by weight, or more specifically 1-3% by weight, based on the total dry weight of the DRL.

As shown in FIG. 6, all of the dispersion samples other than E10 and C13 contain the surfactant Olin-10G ™. In addition, FIG. 6 shows an embodiment of a particular aqueous DRL comprising Olin-10G ™ in combination with one or more dispersants. Useful dispersants are those described below with reference to FIG. 8 and FS-30, which are commercially available from multiple raw material suppliers (eg, Castament® FS-30 by BASF, and Capstone® FS-30 by DUPONT.

[ROC filterability]
In certain embodiments, as described above, dispersants or surfactants are used in the ROC and DRL to enhance the stability of the dispersion. When one or more surfactants and one or more dispersants are contained in the ROC, the filterability is also improved. The modification of the heat-sensitive receptor element of the present invention may contain only one or more surfactants, only one or more dispersants, or a combination thereof in the ROC. It should be understood that it is good. Undesirable accumulation and solidification of dispersed particles of ROC dispersion may be observed in the coating machine during or after the high speed, high shear coating process. The presence of accumulations in the form of deposits and agglomerated particles requires frequent cleaning of coating machinery and replacement of filters during the coating application process. Failure to monitor such accumulation and keep machinery clean can result in impact on coating quality. We have found that by incorporating the appropriate type and amount of dispersant, the stability of the dispersion is significantly enhanced and the filterability is improved. The dispersant protects the latex and dispersed particles (or discontinuous phase particles) in the ROC dispersion from solidifying, coagulating, agglomerating, and coalescing under high shear and high stress conditions. ..

The dispersant used in the present invention is usually random or block copolyma or tarporima. They may be ionic or nonionic and have a weight average molecular weight in the range of 5000-100,000. When the dispersant is random or block copolima, the copolima usually consists of two types of monoma components. That is, one is a hydrophilic monomeric constituent and one is a hydrophobic and / or lipophilic monomeric constituent, such as an aliphatic, aromatic, fat. It is a ring type, an aromatic heterocycle, an alicyclic heterocycle, a polycyclic type, and the like. If the dispersant is a random or blocker polymer, it also consists of two types of monoma components. That is, at least one (but not more than two) hydrophilic monoma components, and at least one (but not more than two) hydrophobic and / or lipophilic monoma components such as aliphatic, aromatic. Group, alicyclic, aromatic heterocycles, alicyclic heterocycles, polycyclics, and aliphatic, aromatic, alicyclic, aromatic heterocycles, alicyclic heteros containing silicone and / or fluorine. Ring, polycyclic, etc.

Examples of dispersants with the above-mentioned properties include, for example, a random copolymer of benzyl methacrylate and methacrylic acid (BE-23, etc.), a random tarpolymer of benzyl methacrylate, octadecyl methacrylate, and methacrylic acid (BOE, etc.). , And benzylcopolyma or tarpolyma of acrylic acid, such as Efka® PX 4701 and Dispex® Ultra PX 4585 manufactured by BASF. In addition, other useful polymer dispersants include E-SPERSE 100 and E-SPERSE 700 from Ethox Chemicals, Zetasperse® Aqueous Dispersant Series from Air Products®, and Lubrizol®. Examples include the Solspec® aqueous superdispersant series and the CRODA Zephyrm ™ aqueous dispersant series.

The results of the filterability test are shown in detail in FIG. FIG. 8 shows the filterability of various ROC dispersions based on the filtrate quality test (“FQT”) method, which is quantified by weight to plug metric of clogging weight (“WTP”, weight to plug). Is shown. To carry out the FQT method, the solution sample is passed through a test filter at a constant pressure. Collect and weigh the filtrate until the aqueous solution stops flowing. When the flow of the solution is stopped, the total weight of the collected filtrate is recorded as WTP (results in FIG. 8 are expressed in grams). The higher the WTP, the better the filterability. The filterability of the dispersion sample in FIG. 8 was tested using a membrane filter having a diameter of 32 mm and a diameter of 1.2 microns. The results of the quantitative FQT measured by WTP are shown in detail from the second column to the last column in FIG. Based on internal testing, we have determined that certain quantitative results will be lower than acceptable. Therefore, we created a qualitative scale to rank and evaluate the various ROC dispersions tested. The qualitative evaluation of the ROC dispersion is shown in the last column in FIG. The conversion from quantitative to qualitative is performed as follows.

Further reference to FIG. 8, the components of each dispersion sample are shown in detail by the data listed in columns numbered from 1 to 10. As shown in the first column, water is a component of all ROC dispersions tested. “L-3% E” in the second row indicates that the water-dispersible acrylic polymer was added to the dispersion. "L-3% E" means that the acrylic latex ("L") constitutes 3% of the previously discussed (b) type carboxy-containing or sulfo-containing ethylenically unsaturated polymerizable acrylate or methacrylate monoma. Represent. “XL-1” in the third row indicates that the cross-linking agent was added to the dispersion. The "P" in the fourth column represents the addition of PEDOT, which is a water-dispersible conductive polymer material, to the dispersion. The "S" in the fifth column indicates that a release agent, that is, a commercially available release agent, Siltech (registered trademark), has been added to the dispersion. The “V” in the sixth row represents the addition of Vylonal® MD-1480, a film-forming water-dispersible polyester, to the dispersion. The 7th and 8th columns represent different solvents added to the dispersion sample. "IBA" represents isobutyl alcohol as a solvent, whereas "DEG" represents diethylene glycol. The 9th and 10th columns show the combination of the surfactant and the dispersant present in the ROC dispersion. The Olin-10G ™ discussed earlier is commonly used as a surfactant, whereas BE-23, BOE, Efka® PX4701, E-SPERSE 100, and E-SPERSE 700 (all). (Discussed earlier) is used as a dispersant. FIG. 8 shows that the ROC dispersion may contain 0, 1, or 2 dispersants. The dispersant may be included in the ROC in an amount of 0.5% to 10% by weight or less, or more specifically in the range of 1% to 4% by weight, based on the total dry weight of the ROC layer. it can. It is understood that when the aqueous coatable ROC and DRL formulations are dried, the solvent evaporates and does not account for any percentage of the dry weight in any of the layers.

[Flexible layer with fine voids]
Dye receptor elements used for thermal dye transfer generally include a support (transparent or reflective), on one or both surfaces of a dye image receptor layer, and optionally an additional layer, such as a support. It has a flexible layer or a cushioning layer between the and the dye receiving layer. 1A and 1B show the aqueous DRL layer above the flexible layer with microvoids. In other embodiments (not shown in the drawings), the dye receiving layer may be coated directly on one or both of the opposing surfaces of the support. Alternatively, as seen in FIGS. 1A and 1B, the aqueous DRL may be coated on top of an additional layer (such as a flexible layer) that is on one or both of the opposing surfaces of the support. The flexible layer provides insulation to retain the heat generated by the thermal head on the surface of the printed matter, and also provides adhesion between the donor ribbon and the receiving sheet, which is essential for uniform print quality. Various methods have been proposed to obtain such a flexible layer. FIGS. 1A and 1B show that a similar flexible layer with microvoids is included between the outermost layer and the support. Those skilled in the art will appreciate that the flexible layer with microvoids may include one or more layers such as a skin layer and a film layer. It should be understood that the flexible layer with microvoids shown in FIGS. 1A and 1B is any type of flexible layer known in the art.

[Support]
The thermal imaging receptor element comprises one or more layers as described above, placed above the appropriate support. As mentioned above, these layers can be placed on one or both surfaces of the support. The thermal image receptor element comprises an aqueous coatingable dye receptor layer from the outermost surface towards the support, and optionally one or more intermediate layers. However, in many embodiments, the aqueous coatable dye receiving layer is placed directly on one or both surfaces of the support. Particularly useful supports include polymer films, or raw paper substrates containing cellulose fibers, or synthetic paper substrates containing synthetic polymer fibers, or resin coated cellulose paper substrates. However, supports of other substrates such as woven fabrics and polymer films can be used. The support may be composed of any material typically used for thermal imaging applications, as long as the layer formulations described herein can be applied appropriately.

The resin used on one or both sides of the paper substrate is a thermoplastic material of appropriate dry thickness that can be adjusted to provide the desired curl properties, such as polyethylene, polypropylene, copolymas of these resins. , Or a polyolefin such as a blend of these resins. The surface roughness of this resin layer can be adjusted to provide desired transportability in a thermal image forming printing press.

The support may be transparent or opaque and may be reflective or non-reflective. Opaque supports include plain paper, coated paper, resin-coated paper such as polyolefin-coated paper, synthetic paper, low-density foam core-based supports and low-density foam core-based paper, printing paper supports, melt-extruded coated paper, and Examples include polyolefin laminated paper.

Paper includes a wide range of papers, from high-grade paper such as photographic paper to low-grade paper such as newspaper. In one embodiment, it is described in US Pat. Nos. 5,288,690 (Warner et al.) And 5,250,496 (Warner et al.) (Both incorporated herein by reference). Ektacolo® paper (Eastman Kodak Co.) can be used. Paper can be made on a standard continuous long net paper machine or other modern paper machine. Any pulp known in the art can be used for papermaking. Hardwood bleached chemical kraft pulp is useful because it provides brightness, a smooth initial surface, and a good texture while maintaining strength. Papers useful in the present invention are generally at least 50 μm to 230 μm or less, typically at least 100 μm to 190 μm or less, because the overall thickness of the image-forming element is thus increased. This is because it falls within the range desired by the customer and the range desired for processing with existing equipment. They can be "smooth" so as not to interfere with viewing the image. Chemical additives to impart hydrophobicity (sizing), wet strength, and dry strength can be used as needed. Inorganic fillers such as _{TiO 2} , talc, mica, BaSO ₄ , and CaCO ₃ clay can optionally be used to enhance the optical properties and reduce costs. Pigments, biocides, and processing chemicals can also be used as needed. The paper can also be subjected to smoothing operations such as dry or wet calendering, as well as coatings through in-line or offline paper coating machines.

A particularly useful support is a paper substrate coated with resin on any surface. The biaxially stretched substrate support comprises a paper substrate and a biaxially stretched polyolefin sheet laminated on one or both surfaces of the paper substrate, typically polypropylene. Commercially available stretched and unstretched polymer films, such as opaque biaxially stretched polypropylene or polyester, can also be used. Such supports can contain pigments, bubbles or bubble voids to enhance their opacity. The support is made of a microporous material such as PPG Industries, Inc. Polyethylene polymer-containing material, Tyvek® Synthetic Paper (DuPont Corp.), impregnated paper, such as Duraform®, and OPPalyte®, sold by (Pittsburgh, Pennsylvania) under the trade name Teslin®. Trademark) films (Mobile Chemical Co.), as well as other composite films listed in US Pat. No. 5,244,861 cited and incorporated herein by reference can also be included. Useful composite sheets are, for example, US Pat. Nos. 4,377,616 (Ashcraft et al.), 4,758,462 (Park et al.), And 4,632,869 ( It is disclosed in Park et al. (The disclosures of which are incorporated herein by reference).

The support may have voids, which means that the voids are formed from the added solid and liquid material, or that the "voids" contain a gas. The void-inducing particles remaining in the finished packaging sheet core are at least 0.1 to 10 μm in diameter and typically have a circular shape to provide voids of the desired shape and size. Should be. Polymer films with fine voids are particularly useful in some embodiments. For example, some commercial products with these properties that can be used as supports are commercially available from ExxonMobil as 350K18 and as KTS-107 (manufactured by HSI, South Korea).

The biaxially stretched sheet has been described as having at least one layer, but may also include additional layers that can play a role in altering the properties of the biaxially stretched sheet. Such layers may contain colorants, antistatic or conductive materials, or slip agents to produce sheets of unique properties. Biaxially stretched sheets can be formed with a surface layer referred to herein as a skin layer, which is expected to improve adhesion or appearance to supports and photographic elements. If desired, biaxial stretching extrusion can be performed in as many as 10 layers to achieve certain desired properties. The biaxially stretched sheet may be made of the same layer of polymer material or may be made of layers of different polymer compositions.

Useful transparent supports include glass, cellulose derivatives such as cellulose esters, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate, polyesters such as poly (ethylene terephthalate), poly (ethylene naphthalate). ), Poly-1,4-cyclohexanedimethylene terephthalate, poly (butylene terephthalate), and their copolymas, polyimides, polyamides, polycarbonates, polystyrenes, polyolefins such as polyethylene or polypropylene, polysulfones, polyacrylic acids, polyetherimides, And can be composed of a mixture thereof. The term "transparent" as used herein means the ability of visible light to pass through without significant bending or absorption.

The support used for the thermal image receptor element can have a thickness of at least 50 μm to 500 μm or less, or typically at least 75 μm to 350 μm. Antistatic agents, whitening agents, antistatic agents or conductive agents, plasticizers, and other known additives can be incorporated into the support if desired.

Useful antistatic agents in substrates (such as raw paper) include, but are not limited to, metal particles, metal oxides, inorganic oxides, metal antimonates, inorganic non-oxides, and electrically conductive polymers. Examples thereof are described in US Patent Application Publication No. 2011/0091667 (above), which is cited and incorporated herein by reference. Particularly useful antistatic agents are inorganic or organic electrolytes. Electrolytes containing alkali metals and alkaline earth salts (or electrolytes), such as sodium chloride, potassium chloride, and calcium chloride, as well as polyacids are useful. For example, as alkali metal salts, lithium polyate, sodium polyate, or potassium polyate, such as polyacrylic acid, poly (methacrylic acid), maleic acid, itaconic acid, crotonic acid, poly (sulfonic acid), or these. Examples include salts of mixed polymers of compounds. Alternatively, the raw substrate support can contain various clays such as smectite clay containing exchangeable ions that impart conductivity to the raw substrate support. Polymerized alkylene oxides, such as those described in US Pat. Nos. 4,542,095 (Sklensky et al.) And 5,683,862 (Majumdar et al.). A combination of an alkylene and an alkali metal salt is useful as an electrolyte.

Antistatic agents are added to the support (such as a raw cellulose substrate support) to 0.5% by weight based on the total dry weight of the support, or typically at least 0.01% to 0%. It can be present in an amount of 0.4% by weight or less.

In another embodiment, the substrate support comprises a synthetic paper (typically cellulose-free) having a polymer core adhered to at least one flange layer. Polymer cores include homopolymers such as polyolefins, polystyrenes, polyesters, polyvinyl chlorides, or other typical thermoplastic polymers; their copolymas or blends thereof; or other polymer systems such as polyurethanes and polyisocyanurates. .. These materials may be foamed to consist of two phases, a solid polymer matrix and a gas phase, by stretching to create voids or by using a foaming agent. Other solid materials may be present in the form of fillers of organic (polymeric, fibrous) or inorganic (glass, ceramic, metal) origin.

In yet another embodiment, the support comprises a synthetic paper (which may not contain cellulose) having a foamed polymer core or a foamed polymer core adhered to at least one flange layer. The polymers described for use in polymer cores can also be used in the production of foamed polymer core layers carried out through several mechanical, chemical or physical means known in the art.

In many embodiments, polyolefins such as polyethylene and polypropylene, blends thereof, and their copolymas are used with chemical foaming agents as matrix polymers in foamed polymer cores. Chemical foaming agents include, for example, sodium hydrogen carbonate and its mixture with citric acid, organic acid salts, azodicarbonamides, azobisformamides, azobisisobutyronitrile, diazoaminobenzene, 4,4'-oxybis (benzenesulfonyl). Hydrazide) (OBSH), N, N'-dinitrosopentamethyltetramine (DNPA), sodium bicarbonate, and other foaming agents well known in the art. Useful chemical foaming agents may be sodium bicarbonate / citric acid mixture, azodicarbonamide, but others may be used. These foaming agents can be used with ancillary foaming agents, nucleating agents, and cross-linking agents.

If the thermosensitive image receptor element contains an aqueous coatable dye receptor layer on only one surface of the support, then a slip layer or anti-curling layer is suitable on the "back surface" (no image formation) of the support. Apply using polymers such as acrylate or methacrylate polymers, vinyl resins such as copolymas derived from vinyl chloride and vinyl acetate, poly (vinyl alcohol-co-vinyl butyral), polyvinyl acetate, cellulose acetate, or ethyl cellulose. Can be useful to do. The backside slip layer may also contain one or more suitable antistatic or anti-conductive agents known in the art. This slip layer may be, for example, a lubricant, such as an oil, or a semi-crystalline organic solid, as described in US Pat. No. 5,866,506 (Tutt et al.), Which is incorporated herein by reference. , For example, beeswax, poly (vinyl stearyl), alkyl ester peroxide, polycaprolactone, silicone oil, or any combination thereof. A useful anti-curling layer can include one or more polyolefins, such as a mixture of polyethylene and polypropylene.

[Method of producing image receptor elements]
<(A) Preparation of an image receiving layer (single layer DRL containing no water-dispersible conductive polymer material) having a dye receiving layer that can be water-based coated as the outermost layer>
The image-receptive layer was prepared by applying an aqueous coatable dye-receptive image-receptive layer formulation to at least one surface of the support. In some embodiments, the same or different aqueous coatable dye receiving layer formulation can be applied to the opposite surfaces of the support to provide both sides of the thermal image receiving element.

The aqueous coatable dye receiving layer formulation to be applied comprises the polymer components of (1) and (2) described above, as well as a polymer binder composition essentially consisting of any optional additions, including the additions. , Surfactants used as emulsifiers to make water-dispersible acrylic polymers, one or more release agents, one or more crosslinkers, and any other additions described herein. .. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 6: 1 or less, or typically at least 1.5: 1 to 5: 1 or less. Preferably, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 9.2: 1 or less. In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 with respect to the water-dispersible polyester, or typically at least 4: 1 to 20: 1 or less. , Or more preferably at least 1: 1 to 20: 1 or less, or even at least 4: 1 to 15: 1 or less. These formulations can be applied to the support using any useful technique, including coating with proper equipment and conditions, such as, but not limited to, hopper coating, curtain coating. , Rod coating, gravure coating, roller coating, immersion coating, and spray coating. As mentioned above for the material of the support, before applying the aqueous coatable dye receiving layer formulation, the support was acid-etched, flame-treated, corona-discharged, or to improve adhesion. It can be treated using any suitable technique, such as glow discharge treatment, or it can be treated with a suitable primer layer.

<(B) Preparation of an image receiving layer (single layer DRL having a water-dispersible conductive polymer material) having a conductive polymer in an aqueous coatingable dye receiving layer as the outermost layer>
The conductive image receiving layer was prepared by applying an aqueous coatable dye receiving image receiving layer formulation containing a conductive polymer to at least one surface of the support. In some embodiments, the same or different aqueous coatable dye receiving layer formulation can be applied to the opposite surfaces of the support to provide both sides of the thermal image receiving element.

The aqueous coatable dye receiving layer formulation to be applied includes the above-mentioned (1) water-dispersible acrylic polymer, (2) water-dispersible polyester, and (3) water-dispersible conductive polymer material component, and optionally. Contains a polymer binder composition essentially consisting of one or more surfactants or dispersants used as emulsifiers for water-dispersible acrylic polymers, including one or more release agents. There is one or more cross-linking agents, and any other additions mentioned above. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 6: 1 or less, or typically at least 1.5: 1 to 5: 1 or less. Preferably, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 9.2: 1 or less. In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 with respect to the water-dispersible polyester, or typically at least 4: 1 to 20: 1 or less. , Or more preferably at least 1: 1 to 20: 1 or less, or even at least 4: 1 to 15: 1 or less. The amount of the water-dispersible conductive polymer material of (3) in the formulation is in the range of> 0.75% to 2%, or 1.0% to 1.25%. These formulations can be applied to the support using any useful technique, including coating with proper equipment and conditions, such as, but not limited to, hopper coating, curtain coating. , Rod coating, gravure coating, roller coating, immersion coating, and spray coating. As mentioned above for the material of the support, before applying the aqueous coatable dye receiving layer formulation, the support was acid-etched, flame-treated, corona-discharged, or to improve adhesion. It can be treated using any suitable technique, such as glow discharge treatment, or it can be treated with a suitable primer layer.

<(C) Preparation of an image receiving layer having a conductive polymer in an overcoat layer that can be coated with water (two-layer DRL (ROC / DRL) having a water-dispersible conductive polymer material in the ROC layer)>
The image receiving layer is composed of two layers, that is, a dye receiving layer that can be coated with water and an overcoat layer that can be coated with water containing a conductive polymer.

The image layer was first prepared by applying an aqueous coatable dye-accepting image-accepting layer formulation to at least one surface of the support. In some embodiments, the same or different aqueous coatable dye receiving layer formulation can be applied to the opposite surfaces of the support to provide both sides of the thermal image receiving element.

The aqueous coatable dye receiving layer formulation to be applied is essentially a polymer binder composition consisting of (1) a water-dispersible acrylic polymer and (2) a water-dispersible polyester component described above, and any additional material optionally. Additives include one or more surfactants or dispersants used as emulsifiers for making water-dispersible acrylic polymers, one or more release agents, one or more cross-linking agents, and There are any other additions described herein. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 6: 1 or less, or typically at least 1.5: 1 to 5: 1 or less. Preferably, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 9.2: 1 or less. In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 with respect to the water-dispersible polyester, or typically at least 4: 1 to 20: 1 or less. , Or more preferably at least 1: 1 to 20: 1 or less, or even at least 4: 1 to 15: 1 or less.

These formulations can be applied to the support using any useful technique, including coating with proper equipment and conditions, such as, but not limited to, hopper coating, curtain coating. , Rod coating, gravure coating, roller coating, immersion coating, and spray coating. As mentioned above for the material of the support, before applying the aqueous coatable dye receiving layer formulation, the support was acid-etched, flame-treated, corona-discharged, or to improve adhesion. It can be treated using any suitable technique, such as glow discharge treatment, or it can be treated with a suitable primer layer.

The dye-receptive layer on at least one surface of the support coated with the water-based coatable dye-receptive layer is then overcoated with an aqueous-coatable dye-accepting image-receptive layer formulation containing a conductive polymer. This prepared an overcoat layer. In some embodiments, the same or different aqueous coatable dye-receptive layer formulation containing a conductive polymer is applied to the opposite surfaces of the support coated with the aqueous coatable dye-receptive layer on both sides. The heat-sensitive image receiving element can be provided.

The aqueous coatable overcoat layer formulation to be applied includes the above-mentioned (1) water-dispersible acrylic polymer, (2) water-dispersible polyester, and (3) water-dispersible conductive polymer material component, and optionally. Contains a polymer binder composition essentially consisting of the additive of one or more surfactants or dispersants used as emulsifiers for making water-dispersible acrylic polymers (as described herein). Description) One or more release agents, one or more cross-linking agents (described herein), and any other additions described herein. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 6: 1 or less, or typically at least 1.5: 1 to 5: 1 or less. Preferably, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 9.2: 1. In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 with respect to the water-dispersible polyester, or typically at least 4: 1 to 20: 1 or less. , Or more preferably at least 1: 1 to 20: 1 or less, or even at least 4: 1 to 15: 1 or less. The amount of the water-dispersible conductive polymer material in the formulation ranges from> 1.2% to 3% by weight,> 1% to 3% by weight,> 1% by weight,> 1.4% by weight. .. These formulations can be applied to the support using any useful technique, including coating with proper equipment and conditions, such as, but not limited to, hopper coating, curtain coating. , Rod coating, gravure coating, roller coating, immersion coating, and spray coating. As mentioned above for the material of the support, before applying the aqueous coatable dye receiving layer formulation, the support was acid-etched, flame-treated, corona-discharged, or to improve adhesion. It can be treated using any suitable technique, such as glow discharge treatment, or it can be treated with a suitable primer layer.

<(D) Two-layer DRL (ROC / DRL) having an additional surfactant and a conductive polymer in the overcoat layer (an additional surfactant and a water-dispersible conductive polymer material in the ROC layer) )) Preparation>
The image receiving layer is composed of two layers, that is, an aqueous coatingable dye receiving layer and an aqueous coatingable overcoat layer containing an additional surfactant and a conductive polymer.

The image layer was first prepared by applying an aqueous coatable dye-accepting image-accepting layer formulation to at least one surface of the support. In some embodiments, the same or different aqueous coatable dye receiving layer formulation can be applied to the opposite surfaces of the support to provide both sides of the thermal image receiving element.

The aqueous coatable dye receiving layer formulation to be applied is essentially a polymer binder composition consisting of (1) a water-dispersible acrylic polymer and (2) a water-dispersible polyester component described above, and any additional material optionally. Additives include surfactants used as emulsifiers for making water-dispersible acrylic polymers, one or more release agents, one or more cross-linking agents, and any of those described herein. There are other additions and so on. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 6: 1 or less, or typically at least 1.5: 1 to 5: 1 or less. Preferably, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 9.2: 1 or less.

In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 with respect to the water-dispersible polyester, or typically at least 4: 1 to 20: 1 or less. , Or more preferably at least 1: 1 to 20: 1 or less, or even at least 4: 1 to 15: 1 or less.

These formulations can be applied to the support using any useful technique, including coating with proper equipment and conditions, such as, but not limited to, hopper coating, curtain coating. , Rod coating, gravure coating, roller coating, immersion coating, and spray coating. As mentioned above for the material of the support, before applying the aqueous coatable dye receiving layer formulation, the support was acid-etched, flame-treated, corona-discharged, or to improve adhesion. It can be treated using any suitable technique, such as glow discharge treatment, or it can be treated with a suitable primer layer.

Next, an additional aqueous coatable dye receiving layer on at least one surface of the support coated with the aqueous coatable dye receiving layer described herein (or as described in (A)). An overcoat layer was prepared by applying an aqueous coatable dye-accepting image-accepting layer formulation containing a surfactant and a conductive polymer. In some embodiments, the same or different aqueous coatable dye receiving layer formulation containing an additional surfactant and conductive polymer is applied to the opposing surfaces of the support coated with the aqueous coatable dye receiving layer. Can be applied to provide a heat-sensitive image-receiving element on both sides.

The aqueous coatable overcoat layer formulations to be applied include the above-mentioned (1) water-dispersible acrylic polymers, (2) water-dispersible polyesters, and (3) water-dispersible conductive polymer material components and additional surfactants. , As well as a polymer binder composition consisting essentially of an optional addition, which includes surfactants used in the emulsification of water-dispersible acrylic polymers, one or more release agents, and one or more. There are cross-linking agents, and any other additions described herein. The weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 6: 1 or less, or typically at least 1.5: 1 to 5: 1 or less. Preferably, the weight ratio of the water-dispersible acrylic polymer to the water-dispersible polyester in such a formulation is at least 1: 1 to 9.2: 1 or less. In certain embodiments, one or more water-dispersible acrylic polymers are present in the polymer binder matrix at least 1: 1 with respect to the water-dispersible polyester, or typically at least 4: 1 to 20: 1 or less. , Or more preferably at least 1: 1 to 20: 1 or less, or even at least 4: 1 to 15: 1 or less.

The amount of water-dispersible conductive polymer material is as discussed above. The amount of additional surfactant added to the formulation is as discussed above.

These formulations can be applied to the support using any useful technique, including coating with proper equipment and conditions, such as, but not limited to, hopper coating, curtain coating. , Rod coating, gravure coating, roller coating, immersion coating, and spray coating. As mentioned above for the material of the support, before applying the aqueous coatable dye receiving layer formulation, the support was acid-etched, flame-treated, corona-discharged, or to improve adhesion. It can be treated using any suitable technique, such as glow discharge treatment, or it can be treated with a suitable primer layer.

After applying the formulation as described in (A)-(D) above, it is dried under suitable conditions of at least 20 ° C to 100 ° C or less, typically at a temperature of at least 60 ° C. .. Drying is carried out in an oven or drying chamber if desired, especially in a manufacturing apparatus or production line. Drying promotes cross-linking of the aqueous image-receptive layer formulation, especially via reactive groups in the water-dispersible acrylic polymer, using the appropriate cross-linking agent. Crosslinking can improve the adhesion of the aqueous coatable dye acceptor layer to the support or any adjacent layer placed beneath the aqueous coatable dye acceptor layer.

If desired, the aqueous coatable dye receiving layer formulation can be dried and then additionally heat-treated to enhance the cross-linking of at least a portion of the water-dispersible acrylic polymer. Performed at a temperature of at least 70 ° C. for the time required to remove at least 95% of the water in the aqueous coatable dye receiving layer formulation, in any suitable manner using a suitable device such as an oven. be able to.

The water-based coatable dye-receptive layer formulation is generally applied uniformly to the support so as to cover most or all of the surface of the support, but to form a predetermined pattern of water-based coatable dye-receptive layer. In some cases, it is applied to the support and dried.

The aqueous coatable dye receiving layer formulation can be applied directly to either one or both sides of the support, but in some embodiments one or more intermediate layer formulations are applied to the support. It can be applied directly to one or both surfaces to provide one or more intermediate layers as described above. One or more intermediate layer formulations can be applied and dried to form one or more intermediate layers, and then one or more intermediate layers on one or both surfaces of the support can be water-based coated. Apply the dye receiving layer formulation. For example, the intermediate layer is coated from the appropriate formulation to provide cushioning, thermal insulation, antistatic properties, or other desirable properties for manufacturability, element stability, thermal image transfer, and image stability. Can be strengthened.

Intermediate layer formulations are also generally aqueous compositions in which various polymer components and any filler, surfactant, antistatic agent, and other desirable components are dispersed or dissolved in water or a water / alcohol solvent. Is applied as. As mentioned above, the intermediate layer formulation can be applied using any suitable technique.

[Heat-sensitive donor element]
The thermal donor element can be used with the thermal image receptor element of the present invention to thermally transfer a dye, transparent polymer film, or metallic effect. Such thermal donor elements generally include an ink or dye-containing layer (which may also be known as a thermal dye donor layer), a thermally transferable polymer film, or a support having a layer of metal particles or flakes on it.

Any ink or dye can be used for the thermal donor element as long as it can be transferred to the dry receptor layer of the thermal image receptor element by the action of heat. Thermal donor elements are, for example, US Pat. Nos. 4,916,112 (Henzel et al.), 4,927,803 (Bailey et al.), And 5,023,228 (Hansel et al.). (Henzel)) (all incorporated herein by reference). Printing methods that transfer thermal dyes may use heat-sensitive donor elements, including poly (ethylene terephthalate) supports coated with regions (eg, patches) where cyan, magenta or yellow inks or dyes are sequentially repeated. Ink or dye transfer steps can be performed sequentially on a color-by-color basis to obtain a multicolor ink or dye transfer image on one or both surfaces of the thermal image receptor element. The support can include black ink for labeling, identification, or writing.

The heat-sensitive donor element is a transparent protective layer (“laminate”) that can be heat-transferred over the heat-sensitive image receptor element (above the transferred dye image or on the non-pigmented portion of the heat-sensitive image receptor element). ) Can also be included. If the process is performed using only a single color, a single color ink or dye transfer image can be obtained.

The thermal donor element customarily includes a support having a dye-containing layer on it. Any dye can be used as the dye-containing layer as long as it can be transferred to the dry image receiving layer by the action of heat.

The thermal donor element can include a single color region (patch) or a multicolor region (patch) containing a dye suitable for thermal printing. As used herein, the "dye" may be one or more dyes, pigments, colorants, or a combination thereof, or may optionally be in a binder or carrier known to those skilled in the art. .. For example, the pigment layer comprises a combination of magenta pigments, a yellow pigment donor patch containing at least one bispyrazolone methine pigment and at least one other pyrazolone methine pigment, and at least one indoaniline pigment. A cyan pigment donor patch containing a cyan pigment can be further included. The dye can be selected in consideration of hue, light resistance, and solubility of the dye in the binder of the dye-containing layer and the binder of the aqueous coatingable dye receiving layer.

Further examples of useful dyes are U.S. Pat. Nos. 4,541,830 (Hotta et al.); 4,698,651 (Moore et al.); 4,695,287 (Evans (Evans). Evans et al.); Nos. 4,701,439 (Evans et al.); Nos. 4,757,046 (Byers et al.); No. 4,734,582 (Evans et al.); Nos. 4,769,360 (Evans et al.); Nos. 4,753,922 (Byers et al.); Nos. 4,910,187 (Sato et al.); Nos. 5,026, 677 (Vanmail); 5,101,035 (Bach et al.); 5,142,089 (Vanmail); 5,374,601 (Takiguchi (Takiguchi) Takachi et al.); No. 5,476,943 (Komamura et al.); No. 5,532,202 (Yoshida); No. 5,635,440 (Eguchi et al.); No. 5,804 , 531 (Evans et al.); 6,265,345 (Yoshida et al.); And 7,501,382 (Foster et al.), And US Patent Application Publication No. 2003 / It can be found in 0181331 (Foster et al.) And 2008/0254383 (Soejima et al.) (The disclosures of which are incorporated herein by reference).

The dyes alone or in combination can be used to obtain a monochromatic pigment donor layer or a black pigment donor layer. The dye can be used in the donor transfer element in an amount such that when transferred, the final dye image is 0.05 g / m ^{2 to 1 g / m 2 or less.}

Dyes and optional additions are generally incorporated into the appropriate binder in the dye-containing layer. Such binders are well known in the art and include, such as cellulose polymers, various types of polyvinyl acetate, polyvinyl butyral, styrene-containing polyol resins, and combinations thereof, and, for example, US Pat. No. 6,692,879. (Suzuki et al.), Nos. 8,105,978 (Yoshizawa et al.) And Nos. 8,114,813 (Yoshizawa et al.), Nos. 8,129,309 (Yokozawa et al.) Et al., And US Patent Application Publication Nos. 2005/0227023 (Araki et al.) And 2009/0252903 (Teramae et al.) (All of which are incorporated herein by reference). Others can be mentioned.

The dye-containing layer can also contain various additives such as surfactants, antioxidants, UV absorbers, or non-transferable colorants in amounts known in the art. For example, useful antioxidants or light stabilizers are incorporated herein by reference, eg, US Pat. No. 4,855,281 (Byers), and US Patent Application Publication No. 2010/0218887 and. No. 2011/0067804 (both Breland). The N-oxyl radical derived from hindered amine, which is described in Bleeland's publication, is used as a light stabilizer for the heat-transferred dye image for protection applied to the transferred dye layer and the transferred dye image. Especially useful for both overcoats.

The polymer film (“laminate”) can be thermally transferred from the donor transfer element to the thermal image receptor element. The composition of such polymer films is known in the art and is incorporated herein by reference, for example, U.S. Pat. Nos. 6,031,556 (Tutt et al.) And 6,369,844 (Neumann (Newman). As described in Neumann) et al.). The two Breeland publications mentioned above describe protective polymer films, their compositions and their use.

In some embodiments, the heat-sensitive donor element comprises a layer of metal or metal salt that can be thermally transferred to the heat-sensitive image receptor element. Such metals can provide metallic effects, highlights, or undercoats for later transferred dye images. Useful metals that can be transferred include, but are not limited to, gold, copper, silver, aluminum, and others as described below. Such heat-sensitive donor elements are, for example, incorporated herein by reference in US Pat. Nos. 5,312,683 (Chou et al.) And 6,703,088 (Hayashi et al.). It is described in.

The backside of the thermal donor element can include, for example, a "slip" layer or a "slippery" layer, as described in the Breeland gazette mentioned above.

[Image formation assembly and thermal image formation]
In order to thermally transfer an image (eg, dye, metal or transparent film) onto one or more surfaces using thermal transfer means, a thermal image receptor element may be added to one or more thermal donors in the assembly of the present invention. It can be used in combination with or "thermally related" to the element. Multiple thermal transfers to the same, opposite, or both surfaces of a heat-sensitive image receptor element can result in a multicolor image, polymer film, or metal image on one or both sides of the substrate of the heat-sensitive image receptor element. Can be brought on. As mentioned above, a layer or pattern of metal can be formed on one or both surfaces of the substrate. In addition, a protective polymer film (topcoat) is applied to one or both surfaces of the substrate, eg, a multicolor image on one or both surfaces of the substrate is coated with a protective overcoat or "laminate". It can also be covered.

Thermal transfer generally involves image-heating the heat-sensitive donor element and the heat-sensitive image receptor element of the present invention, and transferring an image of a dye, metal or transparent film to a heat-sensitive image receptor element as described above to dye, metal. Or it involves forming an image of a polymer film. Thus, in some embodiments, both the dye image and the polymer film are image-transferred from one or more thermal donor elements to the aqueous coatable dye receptor layer of the thermal image receptor element.

Thermal dye donor elements can be used, including poly (ethylene terephthalate) supports coated in regions where cyan, magenta, and yellow pigments (optionally black pigments or pigments) are sequentially repeated, and dyes. When the transfer steps are performed sequentially for each color, a three-color (or four-color) pigment transfer image is obtained on one or both surfaces of the support of the heat-sensitive image receptor element. Thermal transfer of the polymer film can also be achieved in the same or different steps to provide a protective overcoat on one or both surfaces of the support. As mentioned above, the thermal donor element can also be used to transfer metal to one or both sides of the thermal image transfer element.

Thermal printheads that can be used to transfer inks, dyes, metals, or polymer films from thermal donor elements to thermal image receptor elements are commercially available. For example, Fujitsu Thermal Head (FTP-040 MCS001), TDK Thermal Head F415 HH7-1089, or Rohm Thermal Head KE 2008-F3 can be used. Alternatively, other known transfer energy sources, such as lasers, can be used, for example, as described in UK Patent Application No. 2,083,726A, which is cited and incorporated herein by reference.

Image-forming assemblies generally include (a) a heat-sensitive donor element, and (b) a dye-containing layer, polymer film, or metal of the heat-sensitive donor element that is thermally associated or adheres to an aqueous coatable dye-receptor layer. The thermal image receptor element of the present invention is included, which is in an overlapping relationship with the thermal donor element. Image formation can be performed using this assembly using known steps.

When attempting to obtain a three-color image, the image-forming assembly can be formed three times separately while heat can be applied by a thermal printhead or laser. After the first dye has been transferred from the first heat-sensitive donor element, this element can be stripped. The second thermal donor element (or another region of the same thermal donor element with different dye regions) can then be registered with the aqueous coatingable dye receiving layer and the process is repeated. Similarly, the third and subsequent color images can be obtained. Similarly, a metal layer (or pattern) or transparent laminate protective film can be obtained.

The image forming method shall be performed using either a single-head printing device or a dual-head printing device (either head can be used to form an image on one or both sides of the support). Can be done. The double-sided thermal image receptor elements of the present invention can be moved during a printing operation using capstan rollers before, during, or after image formation. In some cases, a double-sided thermal image receptor element is placed in a rotating carousel, which can be used to position any side of the double-sided thermal image receptor element at a position related to the printhead in image formation. Determine. In this way, the transparent film, metal pattern or layer can be transferred to one or both surfaces, along with the various color images transferred.

The two-sided thermal image receptor element of the present invention transfers uniform or pattern-like transfers of metals, including but not limited to aluminum, copper, silver, gold, titanium nickel, iron, chromium, or zinc. , Can also be received on one or both surfaces of the substrate. Such a metallized "layer" may be placed above a monochromatic or multicolored image, or only the metallized layer may be an "image". Metal-containing particles can also be transferred. The metal or metal-containing particles may be transferred with or without a polymer binder. For example, the metal flakes in the heat-softening binder can be transferred, for example, as described in US Pat. No. 5,312,683 (above). Transfer of aluminum powder is described in US Pat. No. 6,703,088 (above). If desired, a plurality of metals can be thermally transferred to obtain a unique metallic effect. For example, one metal can be transferred to form a uniform metal layer, and a second metal can be transferred to provide the desired pattern on the uniform metal layer. The metal or metal-containing particles for transfer can be provided on the ribbon or strip of such material in the thermal donor element.

The following examples are provided to illustrate the practice of the present invention and are by no means limiting.

[Preparation of water-dispersible acrylic polymer copolymer]
Various copolimas were prepared for evaluation in the thermal imaging receptor element. These copolimas were prepared using the following procedures and ingredients. The emulsion of ethylenically unsaturated polymerizable monoma was prepared with the following composition.
Monoma emulsion:
Monoma (Table I) 400g
Water 395g
Rhodocal® A-246L Surfactant (Solvay Rhodia) 5g
Reactor contents:
Water 195g
Rhodocal® A-246L Surfactant 5g
45% KOH 1.54g
"ACVA" 2g

The polymerization procedure was carried out as follows:
1) Water and Rhodocal® A-246L surfactant are added to the reactor and the mixture is heated to 75 ° C.
2) Emulsions are prepared using the ethylenically unsaturated polymerizable monomas shown in Table I below in the starting mol% of each monoma.
3) Azobiscyanovaleric acid (ACVA) free radical initiator and 45% by weight potassium hydroxide are added to the reactor.
4) The monoma emulsion is weighed into the reactor over 6 hours.
5) The reaction mixture is maintained at 75 ° C. for an additional 3 hours, then the reaction mixture is cooled to 25 ° C.
6) Adjust the reaction mixture to the desired pH using 1N KOH.

Table II below shows the chemical properties of the water-dispersible acrylic polymer (as an emulsion) prepared using the ethylenically unsaturated polymerizable monomas shown in Table I.

[Formation of thermal image receptor elements]
All control examples and Examples I1 to I58 of the present invention were prepared using an aqueous image receiving layer formulation designed to be a dye image receiving layer with a dry coverage of 2.2 g / m ^2. In Examples I59 to I73 of the present invention, the aqueous image receiving layer formulation was designed to be an image receiving layer having a dry coverage of ^{1.1 g / m 2.} In addition, all aqueous image-receptive layer formulations are designed to have about 10% solids, which will include all of the solid components of each formulation shown in Table III below.

In the control C1 formulation, all of the solids are water dispersible polyesters (provided from Vylonal® MD-1480, Toyobo® as a 25 wt% aqueous dispersion), which is obtained. It became 100% of the solid of the dye image receiving layer. The control C1 image-receptive layer formulation was prepared by simply stirring and dispersing only the water-dispersible polyester in water, and the control C2 image-receptive layer formulation had 98 solids% of the same water dispersibility. From the polyester dispersion, an additional 2% solid content was obtained from the release agent (Siltech® E2150) and prepared in the same manner.

To prepare control formulations C3 to C31 and formulations I1 to I29 of the present invention, the release agent (35 wt% dispersion) was diluted with about 258 g of water and then the acrylic polymer emulsion (for% solids). (See Table II) was added to this mixture with simple stirring. The control formulations C3 to C31 did not contain a water-dispersible polyester.

For each of the formulations I1 to I29 of the present invention, the resulting image receiving layer was 30% by weight water-dispersible polyester (Vylonal® MD-1480, Toyobo® 25% by weight dispersed in water. Included (provided as body), 67% by weight acrylic polymer, and 3% by weight release agent (Siltech® E2150, provided by Siltech as a 35% by weight medium water dispersion).

For each of the formulations I30-I58 of the present invention, the resulting image-receptive layer was 30% by weight water-dispersible polyester (Vylonal® MD-1480, Toyobo® 25% by weight dispersed in water. 64% by weight acrylic polymer (provided as body), 4% by weight crosslinker (carbodiimide XL-1, provided as 40% by weight aqueous dispersion from DSM), and 2% by weight release agent (Siltech). (Registered trademark) E2150) was included. To prepare the formulations I30-I58 of the invention, the release agent (35% by weight dispersion) was diluted with about 243g of water and then with simple agitation, about 42g of polyester dispersion (25% by weight). % Dispersion) was added to this mixture, followed by acrylic polymer (see Table II for% solids) and carbodiimide crosslinker XL-1 (40% by weight dispersion).

For each of the formulations I59-I73 of the present invention, the resulting image receiving layer was a 15% by weight aqueous dispersion from 15% by weight water-dispersible polyester (Vylonal® MD-1480, Toyobo®). 32% by weight acrylic polymer, 1% by weight crosslinker (carbodiimide XL-1, provided as a 40% by weight dispersion in water from DSM), and 1% by weight release agent (Siltech (provided as). Included registered trademark) E2150).

Each dye image receiving layer formulation is machine-coated on a sample of a base material (such as KTS-107 laminate available from HSI (Korea)) containing a layer having fine voids on the opposite surfaces of the paper base material, and dried. Then, the dry coverage of the obtained dry image receiving layer was 2.2 (or 1.1) g / m ² . None of the thermal image-receptive elements had an intermediate layer between the support and the dry image-receptive layer.

For each of the formulations I74 and I75 of the invention, the resulting image receiving layers were from 9% by weight and 6.8% by weight of water dispersible polyesters (Vylonal® MD-1480, Toyobo®. (Provided as 25% by weight aqueous dispersion), 80.8% by weight and 81.2% by weight acrylic polymer, 9% by weight and 11% by weight crosslinker (Carbodiimide XL-1, 40% by weight from DSM). It contained 1.2% by weight and 1% by weight of release agent (Siltech® E2150), respectively.

Each dye image receiving layer formulation is machine coated and dried on a sample of a substrate (such as ExxonMobil Vulcan laminate available from ExxonMobil (USA)) that contains a layer with microvoids on opposite surfaces of the paper substrate. The dry coverage of the obtained dry image receiving layer was 1.32 g / m ² . None of the thermal image-receptive elements had an intermediate layer between the support and the dry image-receptive layer.

Each of the control and the pigment image receptor layer formulation of the present invention and the obtained thermal image receptor element were evaluated for various properties as follows.

[Coating quality]
The coating quality was visually evaluated (not magnified) and given one of a three-point rating. A "bad" visual rating means that the coated and dried image-receptive layer was not uniform because the coating lines were visible and the crepe wrinkles (mottled) were so noticeable. A visual rating of "OK" means that the quality of the dry image receiving layer was acceptable, although some coating lines and crepe wrinkles were visible. A "good" on visual evaluation means that the dry image receiving layer had a very uniform gloss, was smooth, and had no visually noticeable coating lines or crepes.

[Donator-Receptor Adhesion]
After "printing" or after the formation of a thermal assembly of the donor element and the thermal image receptor element, the adhesive quality of the donor-receptor was visually evaluated (not magnified). A rating of "poor" means that during thermal dye transfer (printing), the dye donor layer in the donor element was generally delaminated from the support of the donor element. The rating of "OK" was that the dye donor layer did not separate from the support of the donor element, but there was chattering noise in the printing press and some of the resulting thermal transfer dye image was It means that there was a chatter line. A rating of "good" means that the resulting thermal transfer dye image had no obvious adhesive defects.

[Change in gray scale]
Smooth gradual changes in optical density are crucial for high quality highlight printing. Therefore, the scale of change in gray scale in the low optical density region, such as in the case of highlight printing, was visually evaluated (not enlarged). This continuously increases the optical density over 18 steps from the minimum density (D _min , or energy step 18) to the maximum density (D _max > 1.5 or energy step 1), resulting in the loss or loss of a particular image. This is done by determining the stage (step x) where the optical density discontinuity was observed, which can also be effectively shown in the sensitivity curve (ie, optical density vs. energy stage) and associated sensitivity data.

An evaluation of "bad" is that _{an optical density difference of <0.015 between step x and step 18 (or D min} ), ie ΔOD, was obtained, or between step x and step 18 (or D _min ). It means that the least squares gradient of <0.002 (absolute value) based on the sensitivity curve was obtained. An evaluation of "OK" gave an optical density difference (ΔOD) of at least 0.010 to 0.058 between step x and step 18 (or D _{min ), or step x and step 18 (or D min).} ) Means that a least squares gradient of at least 0.002 to 0.006 (absolute value) based on the sensitivity curve was obtained. A "good" rating gives an optical density difference of> 0.042 between step x and step 18 (or D _min ), ie ΔOD, or between step x and step 18 (or D _min ). It means that the least squares gradient of> 0.006 (absolute value) based on the sensitivity curve was obtained.

[Neutral D _max (neutral red, green or blue)]
When used in the practice of the present invention, the neutral D _max can be obtained from a given set of dye donor elements, thermal image acceptor elements, and thermal prints imaged using thermal printing conditions. It is a measure of the target maximum optical density of neutral hues that can be achieved. The target neutral hue, or neutral D _max, is composed of a composite of yellow, magenta and cyan pigments that are thermally transferred from the pigment donor element patches of each color, so that the pigments of each color The optical densities, ie, D _max (neutral red), D _max (neutral green), and D _max (neutral blue) in the printed thermal image, are obtained separately using the Gretag Macbeth SpecroScan machine. Can be done. In the results shown in Table III below, the smaller the absolute value, the better, because it shows that the deviation of the image color from the target optical density at _{D max is small, so that the color image is the target optical density.} Because it is close to.

The results of these evaluations are shown in Table III below. From these results, it is clear that the control formulations and thermal imaging receptor elements showed some good qualities, but did not consistently show all of the desired properties. However, the formulations and thermal imaging receptor elements of the present invention have shown desired results for most, if not all, of the required properties.

In particular, in the absence of film-forming polyester, coating quality (as a result of film-forming ability), as well as donor-acceptor adhesion, print uniformity, and dye transfer efficiency, as listed in Table III below. It is clear that the performance of the entire printed matter (image) such as D _{max) has always deteriorated, which is not desirable as a high quality color image.} For example, when compared with controls C3 to C5, I1 to I3 of the present invention, and I30 to 32 of the present invention, the coating quality and donor-receptor adhesion performance of the control are poor compared to the examples of the present invention. Is. Comparisons of controls C8-23 and C-28, I6-I18 of the invention, and I25-I50 of the invention all demonstrated good donor-receptor stickiness, but of control examples. The D _max value was significantly worse than _{the D max} value of the examples of the present invention.

In the absence of acrylic latex (controls C1 and C2), the donor ribbon (element) does not easily separate during the thermal printing process and always adheres firmly to the thermal image receiving element, resulting in severe print and print quality. Caused the problem. In addition, the image-receptor layer of control C1 was more likely to adhere to the opposing surfaces of the thermal image-receptor element, especially when it was in the form of rolls or stacks of cut paper.

A comparison of control C1 (without release agent) and control C2 (release agent) shows that the presence of a water-dispersible release agent in the image acceptor layer formulation allows the donor element to adhere to the heat sensitive image acceptor element during the thermal printing process. Is shown to be reduced.

When the cross-linking agent is present in the dye image receptor layer formulation, the donor-receptor adhesion problem is reduced (donor-receptor exfoliation is improved) and the exfoliation required for the image acceptor layer is required. The agent is running low. This in turn helps to promote the desirable property of improving the adhesion between the transparent laminate protective film and the image receiving layer.

Claims (18)

Including the support, on at least one surface of the support
A conductive thermal image receptor element having an aqueous coatable receptor overcoat layer and an aqueous coatable dye receptor layer.
The aqueous coatable receptor overcoat layer comprises a conductive polymer material, a first dispersant, and a second dispersant.
The aqueous coatable dye receiving layer comprises a water-dispersible stripper, a cross-linking agent, and a polymer binder matrix, wherein the binder matrix is composed of.
(1) hydroxyl, including phospho, phosphonate, sulfo, sulfonate, carboxy, or carboxylate groups, or by crosslinking through a hydroxyl or carboxyl groups, to form an amino ester, urethane, amide or urea groups, water Dispersible acrylic polymer; and (2) Water-dispersible polyester having a Tg of 30 ° C. or lower;
Becomes essential from
The water-dispersible acrylic polymer is present in an amount of at least 55% by weight of the total weight of the aqueous coatable dye receiving layer and in a dry ratio of at least 1: 1 to the water-dispersible polyester.
The first dispersant and the second dispersant are present in cumulative amounts in the range of 0.5% to 10% by weight based on the total dry weight of the receptor overcoat layer.
A conductive thermal image receptor element, characterized in that. The conductive thermal image receptor element according to claim 1, wherein the first dispersant and the second dispersant are independently (a) a random copolymer; (b) a block copolymer of acrylic acid. And (c) a conductive thermal image receptor element selected from the group consisting of blocker polymers of acrylic acid. The conductive thermal image receptor element according to claim 2, wherein the (a) random copolyma, the (b) acrylic acid block copolyma, and the (c) acrylic acid blocker polyma are all hydrophilic. A conductive thermal image receptor element comprising a sex component and a hydrophobic component. The conductive heat-sensitive image receptor element according to claim 3, wherein each of the (a) random copolyma, the (b) acrylic acid block copolyma, and the (c) acrylic acid blocker polyma. It is characterized in that the hydrophobic component is independently selected from the group consisting of aliphatic monomas, aromatic monomas, alicyclic monomas, aromatic heterocycles, alicyclic heterocycles, and polycyclic monomas. , Conductive thermosensitive image acceptor element. The conductive thermal image receptor element according to claim 2, wherein the (a) random copolyma, the (b) acrylic acid block copolyma, and the (c) acrylic acid blocker polymer are all 5. A conductive thermal image receptor element, characterized by having a weight average molecular weight in the range of 000 to 100,000. The conductive thermal image receptor element according to claim 2, wherein the first dispersant is a random copolyma containing benzyl methacrylate and methacrylic acid. Receptor element. The conductive heat-sensitive image receptor element according to claim 6, wherein the first dispersant is in the range of 1% to 4% by weight based on the total dry weight of the receptor overcoat layer. A conductive thermal image receptor element, characterized in that it is present in. The conductive thermal image receptor element according to claim 6, wherein the second dispersant is a block copolyma of acrylic acid. The conductive heat-sensitive image receptor element according to claim 8, wherein the second dispersant is in an amount in the range of 1% to 4% by weight based on the total dry weight of the receptor overcoat layer. A conductive thermal image receptor element, characterized in that it is present in. The conductive thermal image receptor element according to claim 6, wherein the second dispersant is a blocker polymer of acrylic acid. The conductive heat-sensitive image receptor element according to claim 10, wherein the second dispersant is in the range of 1% to 4% by weight based on the total dry weight of the receptor overcoat layer. A conductive thermal image receptor element, characterized in that it is present in. The conductive heat-sensitive image receptor element according to claim 1, wherein the receptor overcoat layer further contains at least one surfactant. .. The conductive thermal image receptor element according to claim 12, wherein the at least one surfactant contains P-isononylphenoxypoly (glycidol). Receptor element. The conductive heat-sensitive image receptor element according to claim 1, wherein the conductive polymer material is poly (3,4-ethylenedioxythiophene) -poly (styrene sulfonate). Conductive thermal image receptor element. The conductive heat-sensitive image receptor element according to claim 1, wherein the thickness of the receptor overcoat layer is in the range of 0.1 μm to 0.62 μm. Image receptor element. The conductive thermal image receptor element according to claim 1, wherein either the first dispersant or the second dispersant is based on the total dry weight of the receptor overcoat layer. A conductive thermal image receptor element characterized by being a random tarpolymer of benzyl methacrylate, octadecyl methacrylate and methacrylic acid in an amount ranging from% to 4% by weight. A method for producing the conductive thermal image receptor element according to claim 1.
(A) The step of applying the aqueous coatable dye receiving layer formulation to one or both of the opposing surfaces of the support, or to another layer on one or both surfaces of the support. The aqueous coatingable dye receiving layer formulation comprises a water-dispersible release agent, a cross-linking agent, and a polymer binder composition, wherein the polymer binder composition comprises.
(1) hydroxyl, including phospho, phosphonate, sulfo, sulfonate, carboxy, or carboxylate groups, or by crosslinking through a hydroxyl or carboxyl groups, to form an amino ester, urethane, amide or urea groups, water Dispersible acrylic polymer; and (2) Water-dispersible polyester having a Tg of 30 ° C. or lower;
Becomes essential from
The water-dispersible acrylic polymer is present in an amount of at least 55% by weight of the total weight of the resulting dry image-receiving layer and is in the polymer binder matrix at least 1: 1 to 9.2 with respect to the water-dispersible polyester. A step; present at a dry ratio of 1 or less, or at least 4: 1 to 20: 1 or less;
(B) The step of drying the aqueous image receiving layer formulation to form a dried image receiving layer on one or both of the opposing surfaces of the support;
(C) A receptor overcoat layer containing a first dispersant, a second dispersant and a conductive polymer material is applied onto at least one surface of a support coated with an aqueous coatable dye receptor layer. Steps; and (D) the aqueous image receptor layer formulation is dried to form a dry receptor overcoat layer on one or both of the opposing surfaces of the support;
Including
The first dispersant and the second dispersant are characterized by being present in a cumulative amount in the range of 0.5% to 10% by weight based on the total dry weight of the receptor overcoat layer. And how. 17. The method of claim 17, characterized in that the same aqueous coatable dye receptor layer formulation and the same receptor overcoat layer are applied to both opposite surfaces of the support. how to.