JP2001341270A - Printed indicator sheet and marking film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed indicator sheet which can be used for a long time even when it is used as a base for a marking film for the fuselage of aircraft (aircraft marking film) and shows rapid peeling resistance and oil resistance. SOLUTION: The printed indicator sheet comprises a support, a printed part fixed to the surface of one of the main sides of the support and a light- transmitting protective layer fixed in such a manner that it covers at least the surface of the printed part. In addition, the protective layer includes a first layer having a printed contact side coming into contact with the printed part and a second layer fixed to the opposite side to the printed contact side of the first layer. The first layer contains a first polyol and a first polyfunctional isocyanate crosslinking agent. The described second layer contains a second polyol and a second polyfunctional isocyanate crosslinking agent. Further, the isocyanate equivalent of the first polyfunctional isocyanate crosslinking agent is 250-2,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed display sheet and a marking film, and more particularly, to a support, and a printing section fixed on one main surface of the support.
A light-transmitting protective layer fixed so as to cover the surface of the printed portion, and an improvement of the printed display sheet,
The present invention relates to a printed display sheet in which the protective layer has improved oil resistance and high-speed peeling resistance. The printed display sheet according to the present invention is suitable for forming a marking film adhered to an outer surface of a body of a vehicle moving at high speed because of its improved high-speed peeling resistance. In addition, since the durability (oil resistance) to the organic phosphate ester oil has been improved, aircraft marking adhered to the outer surface of an aircraft using a hydraulic oil containing the organic phosphate ester oil. Particularly suitable for forming films.

[0002]

2. Description of the Related Art Generally, a substrate used for a marking film, a decorative film or the like includes (1) a support, (2) a printing section fixed on one main surface of the support, and (3) a support. It is formed from a printed display sheet having a light-transmitting protective layer fixed so as to cover the surface of the printed portion. The marking film or the like is formed by fixing an adhesive layer on the back surface of the base material (the other main surface of the support). The printing unit is formed using printing toner or ink by a printing method such as electrostatic printing, silk screen printing, gravure printing, offset printing, or inkjet printing. The protective layer usually contains a light-transmitting resin such as an acrylic polymer. The configuration and manufacturing method of the printed display sheet as described above are described in, for example, JP-A-4-216562, and
No. 1,513,818.

The protective layer is disclosed in, for example, Japanese Patent Application Laid-Open No. 1-2255.
As disclosed in JP-A-51, it is formed from a coating film of a paint containing a light-transmitting resin. The coating material for a protective layer disclosed in this publication is a coating material containing an electron beam-curable urethane acrylate oligomer. The urethane acrylate oligomer is formed by reacting a diisocyanate, a diol having a hydroxyl group at both terminals, and an acrylate compound having a hydroxyl group at the terminal and having a radically polymerizable unsaturated group. The protective layer is usually a single-layer coating film formed by applying a coating material for the protective layer on the surface of a support such as a film and drying to form an uncured coating film and curing the coating film. In the curing reaction of the coating film, the acrylic portion of the acrylate compound proceeds by electron beam irradiation of the unsaturated group, and an acrylic crosslinked structure is formed. In addition, the actual opening Hei 5-76
No. 732 also discloses a decorative film (decorative sheet) containing the same electron beam-curable urethane acrylate and having a three-dimensionally crosslinked single-layer protective layer.

[0004]

However, a protective layer consisting of a single-layer coating film has the following problems. Fast moving vehicles, such as aircraft, cars, trains,
When a single-layer protective layer is used to protect the printed part of the marking film adhered to the outer surface of the body, the high-speed peeling resistance is relatively low, and the protective layer may be peeled off from the support. It was difficult to use over a long period of time. Particularly, as a protective layer of a marking film for an aircraft fuselage moving at a speed of 400 km / hour or more,
It has been particularly difficult to use over a long period of time. On the other hand, uncrosslinked polymers have relatively low oil resistance to hydraulic fluids used in aircraft. Aircraft hydraulic fluids typically contain organophosphate oils. When contacted with such an oil, a marking film having a protective layer made of an uncrosslinked polymer swells in a relatively short time upon contact with a hydraulic oil, and it may be difficult to continue using the marking film. Therefore, an object of the present invention is to provide a printed display sheet having high-speed peeling resistance and oil resistance that can be used for a long time even when used as a base material of a marking film for an aircraft fuselage (aircraft marking film). Is to do.

[0005]

The present invention comprises a support,
A printed display sheet, comprising: a printed portion fixed on one main surface of the support; and a light-transmitting protective layer fixed so as to cover at least the surface of the printed portion. The layer includes a first layer having a print contact surface in contact with a printing unit, and a second layer fixed to a surface of the first layer opposite to the print contact surface, wherein the first layer is A first polyol and a first polyfunctional isocyanate crosslinking agent, wherein the second layer contains a second polyol and a second polyfunctional isocyanate crosslinking agent; NCO (isocyanate) equivalent
The present invention provides a printed display sheet having a thickness of 250 to 2,000, and solves the above problem.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Printed Display Sheet) As described above, the printed display sheet of the present invention comprises a support, a printing section fixed on one main surface of the support, and a printing section of the printing section. A light-transmitting protective layer fixed so as to cover the surface. The feature of this printed display sheet is that the protective layer includes a first layer having a printing contact surface in contact with a printing portion, and a second layer fixed to a surface of the first layer opposite to the printing contact surface. Wherein the first layer comprises a first polyol and a first polyfunctional isocyanate crosslinking agent, and wherein the second layer comprises
NC of the first polyfunctional isocyanate crosslinking agent, which comprises a polyol and a second polyfunctional isocyanate crosslinking agent.
O (isocyanate) equivalent is from 250 to 2,000. Because of these features, even when used as a base material for an aircraft marking film, it is possible to simultaneously provide high-speed peeling resistance and oil resistance at levels that can be used for a long time.

In the present specification, the “NCO (isocyanate) equivalent” of the polyfunctional isocyanate crosslinking agent is
It means the molecular weight of the isocyanate crosslinking agent per NCO (isocyanate) group. The “OH (hydroxyl) equivalent” of the polyol described later means the molecular weight of the polyol per OH (hydroxyl) group.

[0008] The function of the protective layer will now be described in more detail. In the protective layer, the polyol reacts with the polyfunctional isocyanate crosslinking agent to form a crosslinked structure based on urethane bonds. In addition, the protective layer has a multilayer structure including the first layer and the second layer having such a urethane crosslinked structure. The operation of such a multilayer structure can be explained as follows. When the marking film is adhered to the outer surface of the vehicle body that moves at a high speed, the wind force accompanying the high-speed movement becomes a high-speed shearing peeling force and acts to peel off the protective layer. Such peeling is called high-speed peeling (or high-speed shearing peeling). Since the printing section is formed from a solidified printing toner or ink, the printing section itself is usually not crosslinked. Therefore, when the protective layer peels off,
The main destruction mode is the internal cohesive failure of the printing section in contact therewith. If the printed area is not crosslinked, cohesive failure of the printed area occurs with relatively low force. In particular, a printed portion formed from toner using electrostatic printing is liable to be cohesively broken. Therefore, in such a case, the adhesion of the protective layer is relatively low, and the high-speed peeling resistance is relatively weak. On the other hand, when the protective layer has a multilayer structure including the first layer including the urethane crosslinked structure and the second layer as described above, a part or the entirety of the high-speed shearing force as described above is applied to two layers of the protective layer. Are dispersed at the interface. Therefore, it is possible to prevent a peeling force at a level that causes cohesive failure of the printing portion from reaching the printing portion. Also, the first
Since both the layer and the second layer include the urethane crosslinked structure as described above, each layer is tough. Therefore, cohesive failure of each layer of the protective layer can be effectively prevented, and the protective layer itself is not easily destroyed by high-speed shearing force.

Further, since the two layers of the protective layer both contain the same kind of material, a polyol and an isocyanate crosslinking agent,
The interface peeling resistance between the two layers can be easily increased. On the other hand, the printing portion, that is, the material such as the solidified printing toner is diversified and is not always high in affinity with the first protective layer. Therefore, it is necessary to increase the NCO (isocyanate) equivalent of the first polyfunctional isocyanate cross-linking agent of the first layer to 250 or more so as to enhance the adhesion to the printed portion. When the NCO equivalent of the isocyanate crosslinking agent is less than 250, the crosslinking density becomes high, and the adhesion between the first layer and the printed portion decreases. On the other hand, if the NCO equivalent of the cross-linking agent is too large, the cross-linking density decreases and the cohesive failure resistance of the first layer decreases. Therefore, the NCO equivalent of the isocyanate crosslinking agent in the first layer is preferably set to 250 to 2,000. From such a viewpoint, the NCO equivalent of the isocyanate crosslinking agent of the first layer is:
Preferably from 280 to 1,000, particularly preferably from 300 to 7
00 range.

NC of the second isocyanate crosslinking agent of the second layer
The O equivalent is equivalent to the NCO of the first isocyanate crosslinking agent of the first layer.
It is preferred that it is smaller than the equivalent. Thereby, the adhesion between the first layer and the second layer can be effectively increased without impairing the toughness of the entire protective layer. The NCO equivalent of the second isocyanate crosslinking agent is usually 100 or more and less than 250,
The range is preferably from 120 to 240, particularly preferably from 130 to 230. Further, it is preferable that the OH (hydroxyl group) equivalent of the first polyol is larger than the OH equivalent of the second polyol. Thereby, the adhesion between the first layer and the second layer can be more effectively increased without impairing the toughness of the entire protective layer. On the other hand, the second protective layer
When the layer contains the urethane crosslinked structure as described above, the oil resistance of the protective layer, particularly the oil resistance to the above-mentioned phosphate ester-based oil, can be effectively improved.

As long as the effects of the present invention are not impaired, a protective layer may be provided on the second layer (on the surface opposite to the contact surface with the first layer) in addition to the above two layers. Can also be laminated. In such a case, the third layer may include a urethane crosslinked structure as in the second layer. In short, the outermost layer of the protective layer is
By including a urethane cross-linked structure formed from a polyol and an isocyanate cross-linking agent, it is possible to effectively increase the adhesion between the lowermost layer in contact with the outermost layer and the oil resistance to a phosphate ester oil.

The support is usually a sheet-like substrate (sheet substrate). As the sheet substrate, for example, paper, a metal film, a polymer sheet, or the like can be used. As the polymer, a synthetic polymer such as polyvinyl chloride, polyester, polyurethane, acrylic polymer, fluorine polymer, polyolefin and the like can be used. In addition, a laminate sheet substrate composed of two or more sheets can be used as the support. The thickness of the support is usually 20 to
It is 800 μm, preferably 30 to 600 μm.

The printing unit can use a usual method such as electrostatic printing and silk screen printing. In the case of electrostatic printing, for example, an electrostatic printing system “Scotch Print System (trademark)” manufactured by 3M can be used. In this method, a print image is formed on a temporary carrier called a transfer medium, and the print image is formed on a support.
Transfer is performed by heating and pressing to form a printed portion. In this case, a toner receiving layer is disposed on the printing portion forming surface of the support in order to facilitate transfer of a printed image. The toner receiving layer is a resin layer having thermoplasticity at the heating temperature. The printing toner contains a binder resin (usually a mixture of a vinyl chloride-vinyl acetate copolymer / acrylic resin) and a pigment dispersed in the binder resin. Usually, since the pigment concentration is relatively high, the cohesiveness of the toner itself is low, and the toner tends to undergo cohesive failure in the printing portion. Therefore, the above-mentioned protective layer is required to protect the printed portion.

(Polyol) As used herein, the term "polyol" means a polymer or oligomer having two or more hydroxyl groups in a molecule. The OH equivalent of the polyol is usually from 200 to 30,000, preferably from 30 to 30,000.
It is from 0 to 10,000, particularly preferably from 400 to 7,000. Polyols that can be suitably used in the present invention include polyester polyols, polyether polyols, polycaprolactone polyols, acrylic polyols, polycarbonate polyols, and the like. Usually, one or more, preferably two or more polyols are used. It is better to use a mixture of

[0015] The first polyol of the first layer in contact with the printing section preferably comprises a polyether polyol. Thereby, the adhesion between the first layer and the printed portion and the adhesion between the first layer and the second layer can be effectively improved. It is particularly preferable that the first polyol of the first layer contains an acrylic polyol in addition to the polyether polyol. Acrylic polyols can effectively suppress deterioration due to environmental factors due to ultraviolet rays, heat, and the like, and can increase the weather resistance of the protective layer. On the other hand, when the second layer is the outermost layer of the protective layer, the second polyol preferably contains a polyester polyol. Thereby, oil resistance can be effectively improved. It is particularly preferable that the second polyol of the second layer contains an acrylic polyol in addition to the polyester polyol. Acrylic polyols can effectively suppress deterioration due to environmental factors due to ultraviolet rays, heat, and the like, and can increase the weather resistance of the protective layer.

Examples of polyether polyols include 1,6-hexanediol, ethylene glycol,
It is preferable that the main chain contains a polyether unit formed from at least one diol selected from the group consisting of propylene glycol, tetramethylene glycol, and caprolactonediol, and has a hydroxyl group at least at both ends of the main chain. Further, in addition to the diol compound, a triol such as 1,1,1-trimethylolpropane or glycerin may be incorporated in the main chain to have a hydroxyl group in a side chain.

As the polyester polyol, for example, a polyester unit formed from an aliphatic dicarboxylic acid such as adipic acid and hexamethylene dicarboxylic acid, an aromatic carboxylic acid such as isophthalic acid and orthophthalic acid, and the above-mentioned diol are mainly used. Those having a hydroxyl group at both ends of the main chain are preferable. Further, in addition to the above-mentioned diol, the above-mentioned triol can be incorporated in the main chain so that the side chain has a hydroxyl group.

The acrylic polyol is at least one non-hydroxyl (meth) acrylate selected from the group consisting of methyl methacrylate, butyl methacrylate, 2-ethylhexyl acrylate and ethylene glycol methacrylate diester, and methacrylic acid. An acrylic copolymer formed from 2-hydroxyethyl and / or a hydroxy group-containing (meth) acrylate ester of ethylene glycol methacrylate monoester.
In the synthesis of the acrylic copolymer, a copolymerizable monomer such as styrene or (meth) acrylic acid may be used together with the (meth) acrylate.

Since these polyols are used after being crosslinked with an isocyanate crosslinking agent, their physical properties are not particularly limited. For example, the number average molecular weight (styrene conversion) by GPC measurement of a polyol is usually 1,000.
~ 5,000, weight average molecular weight (styrene equivalent)
9,000-80,000. The glass transition point of the polyol after crosslinking is usually 40 to 70 ° C, preferably 45 to 60 ° C.

(Isocyanate Crosslinking Agent) Both the first and second isocyanate crosslinking agents are
As long as it has a predetermined NCO equivalent, a normal one can be used. For example, isophorone diisocyanate,
MDI (diphenylmethane diisocyanate) or those synthesized from starting materials containing at least one diisocyanate selected from the group consisting of hydrogenated MDI and 1,6-hexanediol diisocyanate can be used. For example, (A) the aforementioned triol (1,1,1
-Trimethylolpropane or the like) and a compound obtained by subjecting the above diisocyanate to urethanization reaction, or (B)
Compounds having a biuret structure or an isocyanurate structure obtained by reacting the above-mentioned diisocyanates can be used. Also, to adjust the NCO equivalent,
A crosslinking agent obtained by reacting the above compound with a diol such as polycaprolactone diol can also be used.

(Protective Layer) As described above, each layer of the protective layer comprises:
Each is a layer containing a polyol and a polyfunctional isocyanate crosslinking agent. Each layer of the protective layer is usually formed from a paint film containing these materials. The protective layer is
For example, it is formed as follows. First, a first paint for forming the first layer is prepared. The first paint usually contains a predetermined amount of a polyol, a predetermined amount of a polyfunctional isocyanate crosslinking agent, and a solvent capable of dissolving or dispersing them. These materials are mixed, and a uniform solution or dispersion is formed with a stirring or / and dispersing device to prepare a first paint. As the solvent contained in the first paint, for example, a solvent composed of a compound containing no active hydrogen, such as a ketone solvent such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, and an aromatic hydrocarbon solvent such as toluene and xylene can be used. The mixing ratio of the polyol and the polyfunctional isocyanate crosslinking agent contained in the first paint is usually the number (H1) of OH groups contained in the total mass of the polyol.
And N contained in the total mass of the polyfunctional isocyanate crosslinking agent
Represented by the ratio (H1: N1) to the number (N1) of CO groups,
This ratio may be generally in the range of 0.5: 1 to 1.2: 1, and preferably in the range of 0.7: 1 to 1.1: 1. The concentration of the non-volatile components (polyol, isocyanate, etc.) contained in the whole coating material is usually 8 to 50% by mass,
It is preferably from 10 to 30% by mass.

The first paint prepared in this manner is applied to the surface of a support having a printed portion on the surface, dried and subjected to a crosslinking treatment to form a first protective layer. To apply paint,
For example, a printing method such as silk screen printing or a coating method such as a knife coater or a bar coater is employed. The coating weight at the time of coating is usually 10 to 80 g / m ² , preferably 12 to 70 g / m ² . The drying temperature is usually 60
~ 180 ° C. In addition, the crosslinking treatment is usually performed for 30 minutes.
The heating is preferably performed at a temperature of ６０60 ° C. for 1 to 21 days.

The thickness of the first layer coating film thus obtained is usually 1 to 20 μm, preferably 2 to 15 μm.
The elongation at break of the first layer (at a tensile speed of 300 mm / min) is usually 8 to 30%, preferably 10 to 25%,
Particularly preferably, it is 11 to 20%. If the elongation at break is too small, the adhesion between the first layer, the printed portion and the second layer may be reduced. On the other hand, if the breaking elongation is too large, the first
The cohesive failure resistance of the layer may decrease. In the present specification, the measurement of tensile properties such as elongation at break was performed on a test piece composed of a coating film having a thickness of about 25 μm with a thickness of 300 mm / mm.
It is a value measured at a tensile speed in minutes.

Next, a second layer is formed on the first layer.
The second layer also prepares a second paint for forming the second layer,
This is applied on the first layer, dried and subjected to a crosslinking treatment to form a second layer. The second paint, like the first paint, usually contains a predetermined amount of a polyol, a predetermined amount of a polyfunctional isocyanate crosslinking agent, and a solvent capable of dissolving or dispersing them. These materials are mixed, and a uniform solution or dispersion is formed with a stirring or / and dispersing device to prepare a second paint. As the solvent contained in the second coating material, a solvent composed of a compound containing no active hydrogen, such as a ketone-based solvent and an aromatic hydrocarbon-based solvent, as described above, can be used. In addition, OH contained in the total mass of the polyol contained in the second paint
The ratio (H2: N) of the number of groups (H2) to the number of NCO groups (N2) contained in the total mass of the polyfunctional isocyanate crosslinking agent
2) is usually in the range of 0.5: 1 to 1.2: 1, preferably in the range of 0.7: 1 to 1.1: 1. Similarly, the concentration of non-volatile components contained in the whole coating material is usually 8 to
It is 50% by mass, preferably 10 to 30% by mass.

The second paint prepared in this manner is applied on the first layer on the support, dried and subjected to a crosslinking treatment to form the second layer of the protective layer. At this time, the first layer may be in the middle of the crosslinking treatment or may be completed. As for the application of paint,
Similarly to the first layer, for example, it is performed by silk screen printing. The coating weight at the time of coating is usually 1
It is 0 to 80 g / m ² , preferably 12 to 70 g / m ² .
The drying temperature is usually from 60 to 180 ° C. In addition, the crosslinking treatment is usually performed at a temperature of 30 to 60 ° C. and 1 to 21
Heated during the day.

The thickness of the coating film of the second layer thus obtained is usually 1 to 20 μm, preferably 2 to 15 μm.
The elongation at break of the second layer (at a tensile speed of 300 mm / min) is not particularly limited, but is usually smaller than that of the first layer, preferably 7% or less, particularly preferably 5% or less.

(Marking Film) As described above, the marking film according to the present invention comprises the printed display sheet described above and an adhesive layer fixed on the other main surface of the support provided on the printed display sheet. It has. As the support, there can be used a printing adhesive film provided with a support having a white or plain printing surface in addition to the base sheet. The adhesive film for printing usually has an adhesive layer containing an adhesive such as an adhesive on the surface of the support opposite to the surface to be printed. Specific examples of such an adhesive film for printing include, for example, an adhesive film manufactured by 3M Co., Ltd., which is used in the above-mentioned “Trademark: Scotch Print System”; "Trademark: Scotchcal aircraft marking, part number VS
7322 "and the like.

The support of such an adhesive film for printing is
Usually, vinyl chloride-based polymers (including homopolymers and copolymers), polyesters, ionomers, acrylic polymers, polyurethanes, polyolefin-based polymers, and the like can be used, and if necessary, accept a printing toner or printing ink. The resin layer is disposed on the surface to be printed. As the adhesive for the adhesive layer, for example, an adhesive containing an adhesive polymer can be used. Further, a so-called microsphere-type pressure-sensitive adhesive containing a matrix composed of such a pressure-sensitive adhesive polymer and a plurality of elastic microspheres can also be used. The thickness of the adhesive layer is 6 to 75 μm, preferably 8 to 75 μm.
70 μm, particularly preferably 10 to 60 μm.

On the other hand, in the aforementioned adhesive film for printing for "aircraft marking", a plurality of through holes (normally, 0.5 mm in diameter) communicating from the adhesive surface to the printing surface are provided. This is for the following reason. When an aircraft is flying at a high altitude where the air pressure is low, air may leak from the inside of the aircraft to the exterior surface of the aircraft to which the marking film is adhered. In such a case, it is necessary to prevent the film from swelling without allowing the leaked air to escape through the through hole and stay between the outer surface of the machine body and the marking film. Therefore, the protective layer is fixed so as to cover the printed portion on the surface of the support so as not to close the through hole.
As described above, in order to provide the protective layer so as not to block the through hole, it is preferable to form each layer of the protective layer from a paint film as described above. Preferably, the coating film is formed by silk screen printing. In such a case, the nonvolatile content of the paint is preferably 30% by mass or less. The viscosity of the paint is preferably in a relatively low range, and is usually 100 to 6,000 cps. Also, the mesh of the silk screen printing plate is also in a relatively coarse range,
It is better to select appropriately.

In this way, when providing the protective layer having the above-mentioned multilayer structure, the through-hole is prevented from being closed, and the support, the printing portion, the protective layer, and the adhesive layer are connected to each other by a plurality of through-holes. When provided with holes, the marking film according to the invention is particularly suitable as an aircraft marking film. When such a marking film is adhered to the aircraft fuselage as the adherend and the surface of the fuselage is covered,
The air leaked to the body surface can be effectively released through the through hole. Therefore, swelling of the film due to air leaks can be effectively prevented, and at the same time, the adhesiveness against high-speed shearing-off force and the oil resistance against aircraft hydraulic oil are excellent, and can be used for a long time. In addition, the thickness of the whole marking film is usually 50 μm to 900 μm.

[0031]

Next, the present invention will be described in detail with reference to examples. (Protective Layer) First, the material of the protective layer used in each example will be described. The urethane layer A has an OH equivalent of 1,700.
Of a polyol (1) and an isocyanate crosslinking agent (1) having an NCO equivalent of 390. The thickness of the coating was about 5 μm. The polyol (1) was a mixture of a polyether polyol and an acrylic polyol. The breaking elongation is 13
%, And the breaking strength was 22 N / 25 mm. In addition, these values are about the test piece which consists of a coating film with a thickness of 24 micrometers.
It was measured at a tensile speed of 300 mm / min. The polyether polyol was synthesized from starting materials containing 1,6-hexanediol, ethylene glycol and propylene glycol.
The acrylic polyol is a starting material that contains methyl methacrylate as a main component and also contains 2-ethylhexyl acrylate, ethylene glycol methacrylate diester, 2-hydroxyethyl methacrylate, styrene, acrylic acid, and methacrylic acid. Was synthesized from. Also, isocyanate crosslinking agent (1)
Is 28% by mass of 1,3,5-tris (isocyanatohexamethylene) isocyanurate, and N, N ′,
It was an isocyanate compound obtained from a reaction product containing 15% by mass of N "-tris (isocyanate hexamethylene) biuret and 57% by mass of polycaprolactonediol.

The urethane layer B was a paint film containing a polyol (2) having an OH equivalent of 650 and an isocyanate crosslinking agent (2) having an NCO equivalent of 190. The thickness of the coating was about 7 μm. Polyol (2) was a mixture of polyester polyol and acrylic polyol. The breaking elongation is 3% and the breaking strength is 31 N / 25 mm.
Met. In addition, these values were measured about the test piece which consists of a 26-micrometer-thick coating film. The polyester polyol was synthesized from starting materials containing isophthalic acid, orthophthalic acid, adipic acid, 1,6-hexanediol, ethylene glycol and trimethylene glycol. Further, the acrylic polyol contains butyl acrylate and styrene as main components, and in addition, 2-ethylhexyl acrylate, 2-hydroxyethyl methacrylate, acrylic acid,
And methacrylic acid. Isocyanate crosslinking agent (2)
It was a mixture of isocyanate compounds containing 84% by mass of 5-tris (isocyanatohexamethylene) isocyanurate and 16% by mass of N, N ', N "-tris (isocyanatohexamethylene) biuret.

The urethane layer C comprises a polyol (3) having an OH equivalent of 2,800 and the isocyanate crosslinking agent (2) described above.
And a paint film containing The thickness of the coating is about 7μ
m. Polyol (3) was a mixture of polyester polyol and acrylic polyol. The breaking elongation was 3% and the breaking strength was 22 N / 25 mm. These values were measured for a test piece consisting of a coating film having a thickness of 24 μm. The polyester was synthesized from a starting material containing adipic acid and ethylene glycol. Further, the acrylic polyol contains butyl acrylate and butyl methacrylate as main components, and is synthesized from a starting material containing ethylene glycol methacrylate diester, 2-hydroxyethyl methacrylate, acrylic acid, and methacrylic acid. It was done.

For the acrylic layer A used in the comparative example, a clear coat agent “product number: 6620I” manufactured by 3M was used, and for the acrylic layer B, the clear coat agent “product number: 415J” manufactured by 3M was used.
Were used to form a coating film having a thickness of about 6 μm. As shown in Table 1, the supports used in each example were the above-mentioned adhesive film “product number: 8620” (manufactured by “8620” in the table) manufactured by 3M Company, and “brand name: aircraft marking product” manufactured by the company. VS7322 "(in the table," VS73
22 ").

(Preparation of Marking Film) First, a single-color portion of each of four colors of cyan, magenta, yellow and black was applied to the printing surface of the support using the above-mentioned "Scotch Print (trademark)" system manufactured by 3M Company. And a toner image containing the mixed color portion. A protective layer is formed using each polymer layer (urethane layer or acrylic layer) shown in Table 1 so as to cover the printed portion.
A marking film composed of the printed display sheet with the adhesive layer of each example was completed. Separately, for the evaluation of the high-speed shear peeling resistance described later, a single-color print display sheet having a single-color print portion of each of cyan, magenta, yellow, and black was prepared in four colors for each example. Each layer of the protective layer in each example was formed by silk-screen printing a paint containing the raw material of each polymer layer, and then drying at 85 ° C. for about 2 hours. In the case of a two-layer protective layer, after drying the coating film of the first layer, a second layer was formed, and then a crosslinking treatment was performed. When “VS7322” is used, the non-volatile content and the viscosity of the paint for forming the protective layer and the mesh of the silk screen printing plate are adjusted so as not to block the through-hole, and the protective layer forming operation is performed. went.

(Evaluation of Marking Film) With respect to the marking films of the respective examples prepared as described above, the high-speed shearing peel resistance, oil resistance and weather resistance of the protective layer were evaluated by the methods described below. Table 2 shows the results. Cuts were made in the high-speed shear-peeling resistance protective layer so that the entire thickness of the protective layer penetrated, and 100 cells were formed, each of which was surrounded by the cuts and arranged in a grid pattern. On this cell,
After pressure-bonding an adhesive tape “product number 610” manufactured by 3M, this tape is peeled off at a high speed in a substantially shear direction. In each of the colors, if there was no transfer of cells (fragments of the protective layer) on the tape side, the evaluation was OK, and the other evaluations were NG. Oil-resistant aircraft hydraulic fluid (organic phosphate ester oil, part number LD
After 4) was dropped on the protective layer and left for about 1 hour, the appearance change was visually observed. If no change such as swelling was observed, it was evaluated as OK, and if there was a change such as swelling, it was evaluated as NG. Evaluation of weather resistance Xenon weatherometer manufactured by Toyo Seiki Co., Ltd. (Model: A
Using TLAS Ci65), the gloss retention after the test for 3,500 hours was measured. Gross is Murakami Color Materials Co., Ltd.
It was a 60 ° gloss measured using a gloss meter (Model No .: GMX2020) manufactured by Co., Ltd. Table 2 shows the retention [%] after the test when the gloss before the weather resistance test was defined as 100%.

Examples 1 and 2 are superior to Comparative Examples 1 and 2 (acrylic protective layer) in high-speed shear peel resistance, oil resistance, and weather resistance. On the other hand, in Comparative Examples 3 and 4, high-speed shear peel resistance could not be improved. As described above, in the protective layer having a multilayer structure, part or all of the high-speed shearing peeling force is dispersed at the interface between the two protective layers, and the peeling force at a level that causes cohesive failure of the printing portion reaches the printing portion. Can be avoided. Therefore, the high-speed shear peel resistance was effectively improved. However, it is presumed that such an effect was not obtained in the case of a single protective layer. In Comparative Example 5, the NCO equivalent of the isocyanate crosslinking agent in the first layer of the protective layer was 190, and the optimum range (2
50 to 2,000), the high-speed shear peel resistance could not be improved. In Comparative Examples 3 to 5, since the protective layer had a urethane cross-linked structure, the oil resistance to the organic phosphate-based oil could be improved.

[0038]

[Table 1]

[0039]

[Table 2]

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Hajime Chisaka 323, Toyama, Koyama-cho, Sunto-gun, Shizuoka Prefecture F-term in Sumitomo 3M Limited (Reference) 2C056 EA13 FC06 HA44 4F100 AK51B AK51C AR00D AT00A BA03 BA04 BA07 BA10A BA10C BA10D BA13 BA25B BA25C GB31 HB31A JA20B JA20C JB07 JK06 JL11D JN01B JN01C YY00B YY00C

Claims (4)

[Claims] 1. A printing apparatus comprising: a support; a printing portion fixed on one main surface of the support; and a light-transmitting protective layer fixed so as to cover at least a surface of the printing portion. In the printed display sheet, the first protective layer has a printing contact surface in contact with a printing unit.
A first layer comprising a first polyol and a first polyfunctional isocyanate cross-linking agent, the first layer comprising a second layer fixed to a surface of the first layer opposite to the printing contact surface. The second layer contains a second polyol and a second polyfunctional isocyanate crosslinking agent, and the NCO (isocyanate) equivalent of the first polyfunctional isocyanate crosslinking agent is 250 to 2,000. A print display sheet, characterized in that: 2. The NCO of the second isocyanate crosslinking agent
The printed display sheet according to claim 1, wherein the equivalent weight is smaller than the NCO equivalent weight of the first isocyanate crosslinking agent. 3. The NCO of the second isocyanate crosslinking agent
3. The printed display sheet according to claim 2, wherein the equivalent weight is 100 or more and less than 250. 4. A marking film comprising: the printed display sheet according to claim 1; and an adhesive layer fixed on the other main surface of the support provided on the printed display sheet.