JP2006082354A - Thermal transfer accepting sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer accepting sheet which has an ink accepting layer excellent in the stain resistance to oil content or the like. <P>SOLUTION: The thermal transfer accepting sheet has a base and the ink accepting layer formed on the base. The roughness index (Vr) of the ink accepting layer measured by the Bristow method is 0.1-4 ml/m<SP>2</SP>(with linseed oil used, under pressure of 0.1 MPa). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal transfer receiving sheet excellent in stain resistance.

  Conventionally, a thermal transfer method has been widely used as a simple printing method. In the thermal transfer method, a thermal transfer receiving sheet provided with an ink receiving layer on one side of a substrate is superposed on a thermal transfer ribbon, and the coloring material of the thermal transfer ribbon is selectively placed on the thermal transfer receiving sheet by heating means such as a thermal head. It is the method of transferring to.

As a thermal transfer receiving sheet provided with an ink receiving layer having high receptivity to a color material used in the thermal transfer method, for example, Patent Document 1 has fine projections having an aspect ratio of 2 to 1000 in a three-dimensional direction and average particles. A thermal transfer receiving sheet is described in which fine pigments having a diameter of 0.1 to 10 μm are contained in an ink receiving layer. Patent Document 2 discloses a polyolefin synthetic resin film having specific physical properties, that is, a whiteness of 90% or more, a surface centerline average roughness of 0.3 to 0.55 μm, and 32 kg / cm ² . A thermal transfer receiving sheet is described in which a polyolefin synthetic resin film having a compressibility against stress of 15 to 30% is provided with an ink receiving layer having a thickness of 0.2 to 20 μm.

  Patent Document 3 is based on an ink receiving layer containing 70 to 95 parts by weight of a thermoplastic resin having a glass transition point of 50 to 100 ° C. and 5 to 20 parts by weight of a lubricant with respect to 100 parts by weight of the total solid content. A thermal transfer receiving sheet provided on the surface of the material is described. Patent Document 4 describes a recording receiving sheet in which an ink receiving layer is formed on the surface of a thermoplastic resin film containing 3 to 60 parts by weight of a petroleum resin or a terpene resin. Patent Document 5 discloses that a thermoplastic resin film having a petroleum resin content of 3 to 60% by weight is laminated with a thermoplastic resin film having a petroleum resin content of less than 3% by weight to form a support. A thermal transfer receiving sheet having an ink receiving layer formed on a support is described.

  While many attempts have been made to increase the receptivity of the ink receiving layer to the coloring material, the ink receiving layer is located on the outermost surface of the thermal transfer receiving sheet, and must have excellent stain resistance against dirt such as oil. There is. If the ink receiving layer does not have sufficient stain resistance, the ink receiving layer easily becomes dirty when used in daily life or a factory, making it difficult to use it stably for a long time. Accordingly, there is a strong demand for a thermal transfer receiving sheet that has excellent stain resistance to oil and the like while maintaining appropriate receptivity to color materials.

Japanese Patent No. 2535371 Japanese Patent No. 2555342 Japanese Patent No. 2940673 Japanese Patent No. 3262737 Japanese Patent No. 3344433

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a thermal transfer receiving sheet having an ink receiving layer excellent in stain resistance against oil and the like.

The present invention is a thermal transfer receiving sheet comprising a substrate and an ink receiving layer formed on the substrate, and the roughness index (Vr) of the ink receiving layer measured by the Bristow method is 0. Provided is a thermal transfer receiving sheet characterized by being 1 to 4 ml / m ² (use linseed oil, under pressure of 0.1 MPa).

  According to the present invention, since the roughness index (Vr) is within the above value range, it is possible to provide a thermal transfer receiving sheet having excellent stain resistance against oil and the like.

  Further, the present invention is a thermal transfer receiving sheet comprising a substrate and an ink receiving layer formed on the substrate, wherein the ink receiving layer is formed from a two-component curable resin. A thermal transfer receiving sheet is provided.

  According to the present invention, by using the two-component curable resin, polar groups can be left in the ink receiving layer, and contamination resistance against oils and particularly nonpolar substances can be improved. Further, the use of the two-component curable resin has an advantage that the cross-linking density of the resin is increased and an ink receiving layer having good stain resistance can be obtained.

In the above invention, the ink receiving layer is a thermal transfer receiving sheet formed from a two-component curable resin, and the roughness index (Vr) of the ink receiving layer measured by the Bristow method is 0. 0.1-4 ml / m ² (use of linseed oil, under pressure of 0.1 MPa) is preferable. By using the two-component curable resin, polar groups can be left in the ink receiving layer, and contamination resistance against oils and other nonpolar substances can be improved. Furthermore, since the roughness index (Vr) is within the above value range, it is possible to obtain a thermal transfer receiving sheet having excellent stain resistance against oil and the like.

  Moreover, in the said invention, it is preferable that the said ink receiving layer contains a polar group. This is because if the ink receiving layer contains a polar group, it is possible to improve the stain resistance against oil or other nonpolar substances.

  In the above invention, the two-component curable resin is preferably a two-component curable polyurethane. Since the urethane group itself has polarity, and by intentionally leaving a polar group such as an isocyanate group or a hydroxyl group used when synthesizing the urethane group, polarity can be imparted to the ink receiving layer. It is.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that the thermal transfer receiving sheet which has an ink receiving layer excellent in stain resistance with respect to oil etc. can be provided.

The present invention relates to a thermal transfer receiving sheet. The thermal transfer receiving sheet of the present invention comprises at least a base material and an ink receiving layer formed on the base material, and the ink receiving layer located on the outermost surface of the thermal transfer receiving sheet has excellent resistance to resistance. It is characterized by having contamination. Since the ink receiving layer has excellent stain resistance, it is not easily soiled even when used in daily life or a factory, and can be used stably for a long time.
Hereinafter, each configuration of the thermal transfer receiving sheet of the present invention will be described in detail. First, the most characteristic ink receiving layer in the present invention will be described, and then other components will be described.

1. Ink Receiving Layer First, the ink receiving layer used in the present invention will be described. The ink receiving layer used in the present invention is a layer in contact with a transfer material such as a thermal transfer ribbon during thermal transfer, and a color material heated by a thermal head or the like is transferred thereto. Further, the ink receiving layer is located on the outermost surface of the thermal transfer receiving sheet of the present invention, and is required to have stain resistance.

In the present invention, the ink receiving layer can be roughly divided into two modes. Specifically, an aspect in which the roughness index (Vr) of the ink receiving layer measured by the Bristow method is 0.1 to 4 ml / m ² (use linseed oil, under pressure of 0.1 MPa), and the ink receiving layer Is an embodiment formed from a two-component curable resin. In the present invention, these aspects will be referred to as a first aspect and a second aspect, respectively, and will be described below.

(1) First embodiment The ink receiving layer of this embodiment has a roughness index (Vr) of 0.1 to 4 ml / m ² (use of linseed oil, 0.1 MPa added) as measured by the Bristow method. A reduction). Since the roughness index (Vr) is within the above value range, it is possible to obtain a thermal transfer receiving sheet having excellent stain resistance against oil and the like. In the present invention, if the roughness is the value index (Vr), can be sufficiently exhibited stain resistance, among others 1 to 2 ml / ^{m 2} (linseed oil used, 0.1 MPa pressure A reduction). If it is less than the above range, the thermal transfer ink acceptability and acceptability may be deteriorated.On the other hand, if it exceeds the above range, the thermal transfer receptor sheet of the present invention is likely to become soiled and resistant. This is because the contamination may be deteriorated.

  The Bristow method is a method for measuring the liquid absorption behavior of paper and paperboard. The liquid is brought into contact with a test piece moving at a constant speed, and the liquid transfer amount and absorption time are measured. The roughness index (Vr) used in the present invention is calculated from these data. The roughness index (Vr) evaluates the liquid absorption rate in a short time, and indicates the degree of contamination resistance in the present invention. In the present invention, linseed oil is used as the liquid. The roughness index (Vr) was measured according to the method described in “JAPAN TAPPI Paper Pulp Test Method No. 51: 2000 Paper and Paperboard—Liquid Absorbance Test Method—Bristow Method”.

Moreover, it is preferable that the ink receiving layer of this aspect contains a polar group. This is because if the ink receiving layer contains a polar group, it is possible to improve the stain resistance against oil or other nonpolar substances.
Next, materials used for the ink receiving layer of this embodiment will be described. The ink receiving layer of this embodiment usually contains a resin component and a lubricant.

(I) Resin component The resin component is not particularly limited as long as the roughness index (Vr) according to the Bristow method satisfies the above conditions. For example, polyester urethane resin, polyester resin, acrylic resin Examples thereof include resins, polyolefin-based resins, urethane-based resins, and resins obtained by modifying them. Among them, resins having polar groups are preferable, and polyester urethane-based resins are particularly preferable. This is because the urethane group has polarity and can improve the stain resistance of the ink receiving layer.

  Furthermore, in this embodiment, it is preferable to use a two-component curable resin as the resin component, and it is more preferable to use a two-component curable resin that can impart polarity to the ink receiving layer. By using the above two-component curable resin, an ink receiving layer having polarity can be obtained, and an ink receiving layer exhibiting excellent stain resistance against oil or other nonpolar substances can be obtained. It is. In addition, the use of the two-component curable resin also has the advantage that the crosslink density of the resin is increased and an ink receiving layer having good stain resistance can be obtained. In addition, the said two-component curable resin here is a general term for resin which has the property to harden | cure by raise | generating a chemical reaction between the components contained in resin.

  Further, the method for imparting polarity to the ink receiving layer using the two-component curable resin is not particularly limited as long as a desired ink receiving layer can be obtained. It may be a method using the two-component curable resin to be generated, and the components and reaction conditions of the two-component curable resin are adjusted so that unreacted polar groups of the resin component intentionally remain in the ink receiving layer A method may be used. The two-component curable resin is composed of a main agent and a curing agent that cures the main agent. The ratio of these two components is, as a functional group equivalent, main agent: curing agent = 1: 0.5 to 1: 0. A ratio of .01 is preferred.

Such a two-component curable resin is not particularly limited as long as an ink receiving layer having a roughness index (Vr) by the Bristow method that satisfies the above conditions can be obtained. Polyester urethane resin, two-component curable polyacrylic urethane resin, two-component curable polycarbonate urethane, two-component curable vinyl vinyl chloride vinyl acetate copolymer urethane, two-component curable cellulose urethane, two-component curable polyether urethane, etc. Can be mentioned. Among these, it is preferable to use a two-component curable polyester urethane resin. The urethane group itself has polarity, and furthermore, the polarity is imparted to the ink receiving layer by intentionally leaving the polar group such as isocyanate group and hydroxyl group used when synthesizing the urethane group by the above-described method. This is because it is possible to improve the contamination resistance against oil and other nonpolar substances.
The raw material of the two-component curable polyester urethane is not particularly limited as long as an ink-receiving layer having a Bristow roughness index (Vr) satisfying the above conditions can be obtained. For example, Tolylene-2,4 -The combination of polyfunctional aromatic isocyanates, such as diisocyanate, and polyhydric alcohols, such as a polyol, can be mentioned.

  Further, the mixing ratio of the polyfunctional aromatic isocyanate and the polyol is not particularly limited as long as the ink receiving layer having a roughness index (Vr) by the Bristow method that satisfies the above conditions can be obtained. The ratio of polyfunctional aromatic isocyanate: polyol is preferably in the range of 0.1: 100 to 50: 100.

Further, the content of the resin component in the ink receiving layer is preferably 80 to 95% by mass in the ink receiving layer. If the resin component is within the above range, it is possible to obtain an ink-receiving layer that exhibits good receptivity to a color material transferred from a thermal transfer ribbon or the like, and at the same time has excellent stain resistance to oil or the like. is there. In the present invention, only one type of the above-described resin component may be used, or two or more types may be mixed and used.
Moreover, it is preferable that the molecular weight of the resin component is appropriately selected according to the use and performance of the thermal transfer receiving sheet to be used.

(Ii) Lubricant The lubricant used in this embodiment is used for maintaining good running properties of a thermal transfer ribbon or the like when performing thermal transfer. The lubricant is not particularly limited as long as it does not hinder the colorant acceptability of the ink receiving layer and can keep the running property of the thermal transfer ribbon and the like, but specifically, calcium carbonate. , Silica, barium sulfate and other inorganic lubricants; polytetrafluoroethylene, polyethylene, waxes (fatty acids, aliphatic alcohols, aliphatic amides, etc.), and organic lubricants such as higher fatty acid metal salts (zinc stearate) ; Of these, silica and fatty acid amide are preferably used.

Further, the content of the lubricant is preferably 7 to 20% by mass, more preferably 7 to 15% by mass with respect to the resin component. This is because if the lubricant is within the above range, the running property of the thermal transfer ribbon or the like can be maintained satisfactorily.
Moreover, in this aspect, only 1 type of lubricant mentioned above may be used, and 2 or more types may be mixed and used. In addition, it is preferable to use together the organic type lubricant mentioned above and an inorganic type lubricant from the viewpoint of the said runnability.

(Iii) Other additives In addition to the above-described members, the ink receiving layer of this embodiment may contain a pigment or the like. This is because the surface of the ink receiving layer can be roughened or made porous, and the color material acceptability of the ink receiving layer is improved. Furthermore, you may contain a binder, surfactant, an antifoamer, an antistatic agent, etc. as needed.

(Iv) Film thickness of ink receiving layer Next, the film thickness of the ink receiving layer of this embodiment will be described. The film thickness of the ink receiving layer of this embodiment is not particularly limited as long as the roughness index (Vr) by the Bristow method satisfies the above conditions, but specifically, it may be 1 to 10 nm. preferable. This is because if the film thickness is less than 1 nm, the thermal transfer receiving sheet of the present invention cannot exhibit sufficient contamination resistance, and conversely if the film thickness exceeds 10 nm, it is disadvantageous in terms of cost. .

(V) Manufacturing Method of Ink Receiving Layer The manufacturing method of the ink receiving layer of this embodiment is not particularly limited as long as the roughness index (Vr) by the Bristow method satisfies the above conditions. There is a method of forming an ink receiving layer by applying the above-described resin component and lubricant by a wet coating method using a coating liquid in which a solvent is dispersed or dissolved, and drying and curing the formed coating film. Specific wet coating methods include a gravure roll method, a comma coating method, a bar coating method, and the like. Examples of the solvent include alcohols such as ethanol, propanol and butanol; ketones such as acetone and ethyl methyl ketone; esters such as ethyl acetate and butyl acetate; toluene; xylene; hexane; cyclohexane; . In the present invention, the surface of the ink receiving layer may be subjected to corona discharge treatment, ozone treatment or the like in order to improve the colorant acceptability of the ink receiving layer.

(2) Second Aspect This aspect is an aspect in which the ink receiving layer is formed from a two-component curable resin. By using a two-component curable resin, an ink receiving layer having polarity can be obtained, and an ink receiving layer exhibiting excellent stain resistance against oil or other nonpolar substances can be obtained. Further, the use of the two-component curable resin has an advantage that the cross-linking density of the resin is increased and an ink receiving layer having good stain resistance can be obtained.

  In this embodiment, the method for imparting polarity to the ink receiving layer using the two-component curable resin is not particularly limited as long as a desired ink receiving layer can be obtained. It may be a method using a two-component curable resin in which a functional group is generated, and the components and reaction conditions of the two-component curable resin so that unreacted polar groups of the resin component intentionally remain in the ink receiving layer. It may be a method of adjusting.

Further, the roughness index of the ink-receiving layer of the present embodiment (Vr) is in the above-mentioned Bristow's method, 4 ml / ^{m 2} (linseed oil used, 0.1 MPa pressure) or less, preferably 0.1 to 2 mL ^{/ m} 2 ( It is preferable to use linseed oil under pressure of 0.1 MPa. This is because if the roughness index (Vr) is not more than the above value, a thermal transfer receiving sheet having excellent resistance to contamination with oil or the like can be obtained.

  In addition, the ink receiving layer of this embodiment usually contains additives such as a two-component curable resin component and a lubricant, but since these are the same as those described in the first embodiment, Description of is omitted. Furthermore, since the film thickness of the ink receiving layer and the manufacturing method are the same as those in the first embodiment, description thereof is omitted here.

2. Substrate The substrate used in the present invention is not particularly limited as long as it is used for a general thermal transfer receiving sheet, and specifically, fine paper (acidic paper, neutral paper), Synthetic paper, coated paper, impregnated paper, inter-paper reinforced paper, and the like; transparent, translucent or colored film; plastic, etc. Among them, polyesters such as PET and PBT, polyolefins such as polyethylene and polypropylene are among others. Since it can be obtained inexpensively as a general-purpose film, it is preferably used. Moreover, as a film thickness of the said base material, it is preferable that it is 30 micrometers-120 micrometers.

3. Other Layers In the present invention, in addition to the above members, other layers may be included as necessary. For example, an easy-adhesion primer layer may be installed between the substrate and the ink receiving layer to improve the adhesion thereof, and it adheres to the substrate surface opposite to the surface on which the ink receiving layer is formed. An agent layer and a separator may be provided to form a thermal transfer receiving sheet that can be adhered to an adherend.

(1) Easy adhesion primer layer Moreover, the thermal transfer receiving sheet of the present invention may have an easy adhesion primer layer. The easy adhesion primer layer is provided between the base material and the ink receiving layer, and plays a role of improving the adhesion between them. As a raw material for such an easy adhesion primer layer, for example, polyurethane resin, polycarbonate resin, polyamide resin, acrylic resin, epoxy resin, urethane resin, chlorinated polypropylene, polyethyleneimine, alkyl titanate, and the like can be used. Moreover, a coloring agent, a heat stabilizer, a flame retardant, an ultraviolet absorber, a radical scavenger and the like can be contained as necessary.
The easy-adhesion primer layer is produced using, for example, a method similar to the method for producing the ink-receiving layer described above, by preparing a coating solution obtained by dissolving the above-described material in a solvent. Moreover, it is preferable that the film thickness of the easy adhesion primer layer is appropriately selected within a range of about 1 to 3 μm.

(2) Adhesive layer The thermal transfer receiving sheet of the present invention may have an adhesive layer. The pressure-sensitive adhesive layer is a layer that is formed on the surface opposite to the anaerobic receiving layer of the substrate and adheres to the adherend. The pressure-sensitive adhesive layer may be formed on the entire surface according to the use, or only a desired portion may be selectively formed.
The raw material for the pressure-sensitive adhesive layer is not particularly limited as long as it is used in a general pressure-sensitive adhesive layer. For example, a homopolymer of (meth) acrylic acid ester; (meth) acrylic acid Acrylic adhesives such as copolymers of esters and other monomers; synthetic rubber adhesives such as polyisoprene rubber, polybutadiene rubber, styrene-butadiene rubber; natural rubber adhesives, and the like. Moreover, a tackifier, a crosslinking agent, an antioxidant, an ultraviolet absorber, a silane coupling agent and the like may be added to these as necessary. As used herein, “(meth) acrylate” means methacrylate or acrylate. Further, the thickness of the pressure-sensitive adhesive layer is not particularly limited as long as a pressure-sensitive adhesive layer having a good adhesive force can be formed, but specifically, it is preferably in the range of 5 to 50 μm. .

(3) Separator The thermal transfer receiving sheet of the present invention may have a separator. The separator is stuck on the outer surface of the adhesive layer to prevent the adhesive layer from inadvertently adhering to other substances or blocking when the thermal transfer receiving sheet is wound up. It is a member and is temporarily bonded to the adhesive layer until the thermal transfer receiving sheet is used.
Such a separator is not particularly limited as long as it is generally used. For example, fine paper, linter paper, sulfate paper, glassine paper, kraft paper, polyester resin, olefin resin, etc. Can be mentioned. Moreover, what processed the surface of these members may be sufficient, for example, what coated both sides or one side of the said member with calcium carbonate and talc can be mentioned. Moreover, the film thickness of the said separator will not be specifically limited if it is used for the separator generally used, However, It is preferable to exist in the range of 12-75 micrometers specifically.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  Hereinafter, the present invention will be specifically described with reference to examples.

[Example 1]
In producing the thermal transfer receiving sheet, first, a hard segment made of crystalline polypropylene and a soft segment made of styrene-butadiene rubber are mixed to adjust the elastic modulus to 500 MPa (thickness). A sheet-like base material having a thickness of 80 μm) was prepared, and both surfaces of the base material were subjected to corona discharge treatment as an easy adhesion treatment.

  In addition, 86 parts by mass (main component: curing agent = 1: 0.1 in terms of functional group equivalent ratio) of raw material for two-component curable polyester urethane and 4 parts by mass of fatty acid amide (melting point: about 100 ° C.) 10 parts by mass of silica particles (average particle size 1 μm) were dispersed or dissolved in 100 parts by mass of methyl ethyl ketone to prepare a coating solution for an ink receiving layer.

Furthermore, the coating liquid was applied to one side of the substrate after the corona discharge treatment to form a coating film, and after drying the coating film, cured at 40 ° C. for 3 days, the glass transition point was 55 ° C. An ink receiving layer having a thickness of 1 μm composed of polyester urethane, fatty acid amide as a lubricant and silica particles was formed. Thereafter, an acrylic resin-based pressure-sensitive adhesive composition (PE-115E, manufactured by Nippon Carbide Industries Co., Ltd.) is applied to the back surface of the substrate by a comma coating method to form a coating film, and the coating film is dried. Thus, a pressure-sensitive adhesive layer having a weight per unit area of 20 g / m ² was obtained. Thereafter, a separator having a thickness of 25 μm made of a polyethylene terephthalate sheet subjected to a release treatment on one side is bonded to the outer surface of the pressure-sensitive adhesive layer so that the release treatment surface of the separator is inside, A thermal transfer receiving sheet was obtained.

[Examples 2 to 4, Comparative Examples 1 to 3]
A thermal transfer receiving sheet was obtained in the same manner as in Example 1 except that the functional group equivalent ratio of the main agent and the curing agent in the two-component curable polyurethane raw material was changed.

[Evaluation]
The thermal transfer receiving sheet obtained by the above-described method was evaluated for roughness index (Vr) and stain resistance.
The roughness index (Vr) was measured according to the Bristow method (JAPAN TAPPI paper pulp test method No. 51: 2000 paper and paperboard-liquid absorbency test method-Bristow method). Specifically, the thermal transfer receiving sheet was cut in the flow direction so as to have a width of 25 mm, and linseed oil was dropped under a pressure of 0.1 MPa to obtain the roughness index (Vr) of the thermal transfer receiving sheet.
Regarding the stain resistance, first, printing was performed on the thermal transfer receiving sheet using a thermal printer (Sato, MR410e) equipped with a thermal transfer ribbon (110-A manufactured by Ricoh). Next, according to the JAS special plywood contamination special A test, black magic, red crayon, and blue ink were adhered to the printed thermal transfer receiving sheet, and 2 hours later, lacquer thinner (Japanese Industrial Standard K5538) was impregnated. The surface of the thermal transfer receiving sheet was wiped off using a cloth. These results are shown in Table 1.

As is apparent from Table 1, in Examples 1 to 4, all showed excellent stain resistance, but in Comparative Examples 1 to 3, each contaminant could not be wiped off well.

Claims (5)

A thermal transfer receiving sheet comprising a substrate and an ink receiving layer formed on the substrate, wherein the roughness index (Vr) of the ink receiving layer measured by the Bristow method is 0.1 to 4 ml. / M ² (use of linseed oil, under pressure of 0.1 MPa), a thermal transfer receiving sheet.   A thermal transfer receiving sheet comprising a base material and an ink receiving layer formed on the base material, wherein the ink receiving layer is formed of a two-component curable resin. A thermal transfer receiving sheet comprising a substrate and an ink receiving layer formed on the substrate, wherein the roughness index (Vr) of the ink receiving layer measured by the Bristow method is 0.1 to 4 ml. The thermal transfer receiving sheet according to claim 2, which is / m ² (use of linseed oil, under pressure of 0.1 MPa).   The thermal transfer receiving sheet according to any one of claims 1 to 3, wherein the ink receiving layer contains a polar group. The thermal transfer receiving sheet according to any one of claims 2 to 4, wherein the two-component curable resin is a two-component curable polyurethane.