JP2000212232A - Active energy ray-curable resin composition and coating agent for release document sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an active energy ray-curable resin composition which, when applied on a sheet substrate and cured by an active energy ray irradiation, forms a coating layer which exerts little adhesion at a normal state at an ordinary temperature and pressure but exerts a releasable pseudo-adhesion through compression and retains the pseudo-adhesion property over time. SOLUTION: This active energy ray-curable resin composition comprises (A) from 15 to 70 wt.% base polymer, (B) from 30 to 85 wt.% reactive diluent, (C) from 0 to 10 wt.% additive per the total weight of (A) the base polymer and (B) the reactive diluent, and (D) from 0 to 20 wt.% photopolymerization initiator. Here, (A) the base polymer comprises a copolymer obtained by copolymerizing (a1) from 10 to 60 wt.% rosin-containing α,β-unsaturated monomer, (a2) from 20 to 80 wt.% (meth)acrylic ester having a 4-12C alkyl group and (a3) from 0 to 70 wt.% α,β-unsaturated monomer which is copolymerizable with the above (a1) and (a2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active energy ray-curable resin composition and a coating agent for a peelable form sheet. The coating agent for the sticking and peeling form sheet,
It is used after being applied to a release form sheet used for a laminated postcard or the like.

[0002]

2. Description of the Related Art In recent years, in order to automate the notification work and reduce the mailing cost, a mail using a bonded postcard in which a notification portion of a postcard is concealed has been provided instead of a sealed postcard. In order to conceal the contents of the notification, the laminated postcard can be folded in two or three or the like and folded and temporarily adhered (pseudo-adhered) by pressure, but can be easily A release form sheet capable of peeling off the contact surface and opening the concealed contents is used. As such a release form sheet,
Since the surface finish is good, a film in which a pseudo-adhesion layer is provided on the surface of a printed material applied to a sheet substrate with an adhesive is widely used.

[0003] However, the above-mentioned exfoliated form sheet is disadvantageous in that the cost is high, and since the film is bonded to the sheet base material, it is difficult to regenerate the paper when paper is used as the sheet base material. . To compensate for this drawback, there has been proposed a method in which a coating material comprising a UV-curable resin and an appropriate amount of a pressure-sensitive adhesive is directly applied to a sheet substrate (Japanese Patent Application Laid-Open No. 8-188724).
Although it exhibits pseudo-adhesion, it has the disadvantage that it adheres to the sheet substrate when it is stacked or wound up, since it has adhesiveness even after irradiation with ultraviolet light. In addition, there is a drawback that the adhesive is sticky even when peeled off after pseudo-adhesion, so that it adheres to other postcards or the like.

[0004] Further, the pressurizing step of pseudo-adhering the release form sheet is not limited to immediately after a coating agent is applied to the sheet base material and cured to form a coating layer.
The coating layer formed on the sheet substrate is also required to maintain pseudo-adhesion over time.

[0005]

According to the present invention, when a sheet substrate is coated and irradiated with active energy rays and cured, it has almost no tackiness in a normal state at normal temperature and normal pressure. An object of the present invention is to provide an active energy ray-curable resin composition which can form a coating layer which can be pseudo-adhered releasably by pressure and which can maintain pseudo-adhesion even with time.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, the following rosin-containing monomer and a specific (meth) acrylic acid ester have been used as main constituent components. According to the active energy ray-curable resin composition using the copolymer as a base polymer, the above object can be achieved, and the present invention has been completed.

That is, the present invention relates to (A) base polymer 15
-70% by weight and (B) 30-85% by weight of a reactive diluent, and furthermore (C) no additives based on the total weight of (A) the base polymer and (B) the reactive diluent.
-10% by weight and (D) 0-20% by weight of photopolymerization initiator
An active energy ray-curable resin composition comprising: (a1) 10 to 60% by weight of a rosin-containing α, β-unsaturated monomer; 20 to 80% by weight of a (meth) acrylate having an alkyl group of 4 to 12 and (a3) the (a)
1) α, β-unsaturated monomer copolymerizable with (a2) 0
An active energy ray-curable resin composition comprising a copolymer obtained by copolymerizing the active energy ray-curable resin composition; and a coating agent for a release form sheet using the active energy ray-curable resin composition. About.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The (A) base polymer of the active energy ray-curable resin composition of the present invention is as described above.
(A1) a rosin-containing α, β-unsaturated monomer, (a2) a (meth) acrylate having an alkyl group having 4 to 12 carbon atoms and (a3) copolymerizable with the above (a1) and (a2) Is a copolymer obtained by copolymerizing various α, β-unsaturated monomers. In addition, (meth) acrylic acid ester means methacrylic acid ester and / or acrylic acid ester, and (meth) in the present invention has the same meaning.

Examples of the (a1) rosin-containing α, β-unsaturated monomer include rosin-modified (meth) acrylates such as rosin epoxy (meth) acrylate and rosin ester (meth) acrylate. Examples of the rosin epoxy (meth) acrylate include a reaction product of a rosin and glycidyl (meth) acrylate, and a (meth) acryl monomer having a rosin and an alicyclic epoxy group (for example, Daicel Chemical Industries, Ltd.) ), A reaction product of a glycidyl ester of a rosin with (meth) acrylic acid,
Further, a product obtained by reacting a hydroxyl group of the reaction product with a dicarboxylic acid such as succinic anhydride or phthalic anhydride, and a product obtained by reacting a hydroxyl group of the reaction product with an isocyanate compound are exemplified. Examples of the rosin ester (meth) acrylate include esterified products of rosins with hydroxyalkyl (meth) acrylate such as hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.
The rosins used herein include so-called raw rosins such as gum rosin, wood rosin, tall oil rosin, and so-called stabilized rosins such as distilled rosin, hydrogenated rosin, disproportionated rosin, and colorless rosin. Stabilized rosin is preferred in consideration of the stability when left. These (a1) components can be used alone or in combination of two or more.

[0010] The (a1) rosin-containing α, β-unsaturated monomer is obtained by adding a resin composition of the present invention using a copolymer (A) as a base polymer to a base sheet. It is considered that this contributes to maintaining the long-term pseudo-adhesion performance of the coating layer formed by application and curing. Although the reason is not clear, the surface state becomes more stable by introducing a rosin derivative, which is generally mixed and used as a tackifier for rubber-based and acrylic-based pressure-sensitive adhesives, into the copolymer, and the long-term It is presumed that good pseudo-adhesion performance can be maintained.

(A2) Examples of the (meth) acrylate having an alkyl group having 4 to 12 carbon atoms include, for example,
Examples thereof include butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, and lauryl (meth) acrylate.
These alkyl groups include not only linear alkyl groups but also branched alkyl groups. For example, octyl groups include 2-ethylhexyl and the like. Among these (a2) components,
2-Ethylhexyl acrylate is preferred. These (a
2) The components can be used alone or in combination of two or more.

(A3) α, β-unsaturated monomers copolymerizable with the components (a1) and (a2) include, for example, styrenes such as styrene, α-methylstyrene and vinyltoluene; ) (Meth) acrylates having an alkyl group having 1 to 3 carbon atoms, such as methyl acrylate, ethyl (meth) acrylate and propyl (meth) acrylate; stearyl (meth) acrylate, behenyl (meth) acrylate (Meth) acrylate having an alkyl group having 13 to 22 carbon atoms such as dimethylaminoethyl (meth) acrylate, dimethylaminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) Acrylamide,
Nitrogen-containing (meth) acryloyl compounds such as acryloylmorpholine and N-vinylformamide; and others, vinyl acetate, (meth) acrylonitrile, divinylbenzene, maleic acid diester and the like. These (a3) components can be used alone or in combination of two or more. The component (a3) is appropriately selected depending on the use of the resin composition of the present invention. For example, when used as a release form sheet coating agent,
It is determined in consideration of adhesiveness, curability, appropriate viscosity and the like.

The components (a1), (a2) and (a3) are used in amounts of 10 to 60% by weight of component (a1), 20 to 80% by weight of component (a2), and 0 to 0% of component (a3).
70% by weight. When the component (a1) is less than 10% by weight, the ratio of rosin contained in the copolymer becomes small, and the pseudo-adhesion performance of the coating layer is not sufficiently maintained. From these points, it is preferable that the component (a1) be 15% by weight or more. On the other hand, when the component (a1) exceeds 60% by weight, the glass transition temperature of the copolymer increases,
The adhesiveness of the coating layer tends to decrease, and pseudo adhesion does not occur during pressure bonding. From these points, the component (a1) is 5
It is preferably at most 5% by weight. On the other hand, if the component (a2) is less than 20% by weight, the glass transition temperature of the copolymer tends to be high, and the adhesiveness of the coating layer tends to decrease.
From these points, it is preferable that the component (a2) be 25% by weight or more. On the other hand, when the component (a2) exceeds 80% by weight, the glass transition temperature of the copolymer becomes low, the adhesiveness of the coating layer becomes too large, and the coating layer adheres only by folding. From these points, the component (a1) is 75
% By weight or less. (A3) Component is 0 to 5
It is preferably 0% by weight.

(A) The copolymer as the base polymer is
The components (a1), (a2) and (a3) can be easily produced by using a predetermined amount of each of the components and subjecting the mixture to radical polymerization. The method of radical polymerization is not particularly limited, and a known method such as a solution polymerization, a suspension polymerization, or a bulk polymerization method can be appropriately selected, but the solution polymerization method is usually most suitable. In the polymerization, ordinary reaction conditions can be appropriately adopted. For example, when the solution polymerization method is adopted, the charging of each component may be performed by dropping charging, simultaneous charging, or split charging,
Generally, the polymerization temperature is about 60 to 145 ° C, and the reaction time is about 2 to 8 hours. It is sufficient that various known polymerization catalysts and radical polymerization initiators are appropriately selected and used.

The reactive diluent (B) of the present invention includes, for example, acrylic oligomers and acrylic monomers having a (meth) acryloyl group, and various known ones can be used without any particular limitation. Specifically, monofunctional (meth) acryloyl compounds such as acryloylmorpholine and N-vinylformamide, hexanediol diacrylate, nonanediol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, bisphenol A tetraethylene glycol Trifunctional or more trifunctional such as bifunctional (meth) acryloyl compounds such as diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, and ethylene oxide-modified trimethylolpropane triacrylate. (Meth) acryloyl compounds. Among these reactive diluents (B), because the coating layer is excellent in storage stability after the application of the coating layer and the pseudo-adhesion thereof (the adhesive strength increases with time, and the coating layer does not block and cannot be peeled). It is preferable to use a trifunctional or higher functional (meth) acryloyl compound, and the trifunctional or higher functional (meth) acryloyl compound is one of the reactive diluents (B).
It is preferably contained in an amount of 0 to 100% by weight. (B)
The reactive diluent is determined in consideration of the compatibility with the base polymer (A), curability, adhesion, proper viscosity, and the like, and can be used alone or in an appropriate combination.

The active energy ray-curable resin composition of the present invention comprises (A) a base polymer comprising the copolymer obtained from the above (a1) to (a3) and (B) a reactive diluent. The use ratio is determined based on the coating viscosity of the obtained resin composition. That is, the active energy ray-curable coating agent of the present invention comprises (A) 15 to 70% by weight of a base polymer and (B) a reactive diluent 30.
~ 85% by weight. When the content of the base polymer (A) is less than 15% by weight, the degree of good pseudo-adhesion performance of the base polymer (A) is reduced, and the coating layer does not pseudo-adhere. (A) When the content of the base polymer is more than 70% by weight, there is a problem that the obtained resin composition has a high viscosity and coating workability is lowered, and the glass transition temperature of the cured film is lowered. It has high adhesiveness, and it adheres just by folding. From these points, the content of the base polymer (A) is preferably 65% by weight or less,
(B) The reactive diluent component is preferably 35% by weight or more.

The active energy ray-curable resin composition of the present invention can optionally use an additive (C) as an optional component, and the amount of the additive is determined by the components (A) and (B). Is 10% by weight or less based on the total weight of
Specific examples of the additive (C) include a polymerization inhibitor, a filler,
Slip agents, leveling agents, thixotropic agents, defoamers and the like. Further, the active energy ray-curable resin composition of the present invention generally uses a photopolymerization initiator (D) when it is cured with ultraviolet rays, and is not particularly required when it is cured with an electron beam. As the photopolymerization initiator, various known photopolymerization initiators can be used without any limitation, and the amount of the photopolymerization initiator is 20% by weight or less, preferably 12% by weight, based on the total weight of the components (A) and (B). % Or less. Specific examples of the photopolymerization initiator (D) include Darocure 1173 and Irgacure 6
51, Irgacure 184, Irgacure 907
(Registered trademark of Ciba Specialty Chemicals), benzophenone, o-benzoylbenzoic acid methyl ester, p-dimethylaminobenzoic acid ester, p-
Dimethylacetophenone, thioxanthone, alkylthioxanthone, amylphosphine oxide-based compound, oligo [2-hydroxy-2-methyl-1--4-
(1methylvinyl) phenylpropanone] (Ezacure KIP150, manufactured by Lamberti Co.), amines and the like. These can be used alone or in an appropriate combination.

The active energy ray-curable resin composition of the present invention thus obtained is used, for example, as a coating agent for a release form sheet. Such a coating agent is usually applied to various sheet base materials after printing. The coating method is not particularly limited, and known methods such as a roll coater, a gravure coater, a flexo coater, an offset printing machine, and a screen printing machine can be appropriately employed. After the coating agent is applied, curing is performed by irradiation with active energy rays in a usual manner, and a release form sheet can be obtained.The release form sheet thus obtained is
The printed information is folded and folded in three or the like, and the printed information is quasi-adherently concealed so that it can be peeled off by applying pressure, and then sent to the recipient. When irradiating an ultraviolet ray as an active energy ray, a low-pressure or high-pressure mercury lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge lamp or a carbon arc lamp can be used. For example, a Kocroft-Walton type, a Vandegraf type, or a resonant transformer type can be used.

[0019]

The active energy ray-curable resin composition of the present invention is almost tacky under normal conditions of normal temperature and normal pressure when applied to a sheet substrate and cured by irradiation with active energy rays. On the other hand, it is possible to form a coating layer that can be pseudo-adhered releasably by applying pressure and is useful as a coating agent for a release form sheet. In addition, since the coating layer can maintain pseudo-adhesion over time, after applying a coating agent and curing with active energy rays, there is no need to directly apply pressure to create a release form sheet, and after storing for a long time, A release form sheet can be created by applying pressure at any time. The release form sheet thus obtained is
The surface finish is good, and the film can be manufactured at a lower cost than a film obtained by laminating a film to a sheet substrate. Further, when paper is used as the sheet base material, the paper has a feature that the paper can be recycled.

[0020]

EXAMPLES The present invention will be specifically described below with reference to production examples and examples, but the present invention is not limited to only these examples. In each example, all parts and percentages are by weight unless otherwise specified.

Production Example 1 (Production of (A) Base Polymer) 100 parts of xylene was charged into a reactor equipped with a stirrer, a cooling pipe, a dropping funnel and a nitrogen introduction pipe, and then commercially available rosin epoxy was added to the dropping funnel. Acrylate (manufactured by Arakawa Chemical Industry Co., Ltd., trade name: Beam Set 101, hereinafter R
40 parts of EPA), 40 parts of 2-ethylhexyl acrylate (hereinafter, referred to as EHA), 20 parts of methyl methacrylate (hereinafter, referred to as MMA), and 2,2'-azobisisobutyronitrile (hereinafter, referred to as AIBN). ) 3
Parts of the mixed solution was charged into the dropping funnel. Then
The mixed solution was added dropwise to the system at 130 ° C. over 4 hours under a nitrogen stream, and the reaction was further continued for 1 hour to complete the polymerization. After completion of the reaction, the temperature was raised to 160 to 170 ° C., and xylene was distilled off under reduced pressure at the same temperature for about 1 hour at 30 mmHg to obtain a target copolymer.

Production Examples 2 to 7 The reaction was carried out in the same manner as in Production Example 1 except that the kind or amount of the monomer used in Production Example 1 was changed as shown in Table 1, to obtain a target copolymer. . In the table, RESA means rosin ester acrylate (esterified product of disproportionated rosin and hydroxyethyl methacrylate), and BA
Means butyl acrylate, ST means styrene, and SMA means stearyl methacrylate.

[0023]

[Table 1]

Example 1 (Preparation of active energy ray-curable resin composition) (A) Copolymer 4 obtained in Production Example 1 as base polymer
0 parts, (B) 30 parts of nonanediol diacrylate (hereinafter, referred to as NDDA) as a reactive diluent and ditrimethylolpropane tetraacrylate (hereinafter, DTM)
30 parts of (PTA), 5 parts of (D) Irgacure 184 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and (C) 0.1 of methoquinone as a polymerization inhibitor
The part is weighed in a beaker and stirred and dissolved under heating at 80 ° C.
An active energy ray-curable resin composition was prepared.

Examples 2 to 7 and Comparative Examples 1 to 5 In Example 1, the type or amount of the base polymer (A) or the type or amount of the reactive diluent (B) was changed as shown in Table 2. Otherwise in the same manner as in Example 1, an active energy ray-curable coating agent was prepared. In the table, TMPTA means trimethylolpropane triacrylate.

[0026]

[Table 2]

(Preparation of Release Form Sheet) The coated active paper was coated with the active energy ray-curable resin composition obtained in the example or the comparative example using a bar coater # 3, and then a high-pressure mercury air-cooled lamp ( 120W / cm, irradiation distance 10c
m) to irradiate ultraviolet rays (belt speed 10 m /
Min) to obtain a release form sheet. The performance of the obtained release form sheet was evaluated under the following conditions. Table 3 shows the results
Shown in

(Condition A-Adhesion when pressurized directly after forming the sheet) After forming the release form sheet, the sheet is cut immediately to a width of 10 cm, folded in two so that the coating layers are in contact with each other, and then placed on a table. Pressing linear pressure 100kg / c with a roll press (Yuri Roll Machine Co., Ltd., MSC-29)
m, and then cut into 2.5 cm widths.
It was left in a constant temperature and humidity room at 5 ° C. and 50% RH. Immediately after pressurization,
After 1 day and 7 days, the test substrate was manually peeled off, and the state of the coating layer was visually determined.

(Condition B-Adhesion when pressurized after standing for 14 days after sheet creation)
After leaving in a constant temperature and humidity room of 25 ° C and 50% RH for 4 days,
The above test was performed.

[0030]

[Table 3]

In Table 3, "pseudo adhesion" means that the peeled coating layer is in the same state as before lamination, "not adhered" means that it did not adhere when pressed, and "non-peelable" It means that the coating layer is completely adhered and cannot be peeled off by hand.

Claims (4)

[Claims] (A) 15 to 70% by weight of a base polymer
And (B) 30 to 85% by weight of a reactive diluent, and (C) 0 to 10% by weight of an additive based on the total weight of (A) the base polymer and (B) the reactive diluent.
And (D) an active energy ray-curable resin composition containing 0 to 20% by weight of a photopolymerization initiator, wherein the (A) base polymer is (a1) a rosin-containing α, β-
10 to 60% by weight of unsaturated monomer, (a2) carbon number of 4-1
(Meth) acrylate 2 having two alkyl groups
0 to 80% by weight and (a3) the above (a1), (a2)
An active energy ray-curable resin composition, comprising a copolymer obtained by copolymerizing 0 to 70% by weight of an α, β-unsaturated monomer copolymerizable with the above. 2. The active energy ray-curable resin composition according to claim 1, wherein (a2) the (meth) acrylate having 4 to 12 carbon atoms is 2-ethylhexyl acrylate. 3. The active energy ray-curable resin composition according to claim 1, wherein (B) the reactive diluent contains a trifunctional or higher functional (meth) acryloyl-based compound. 4. A coating agent for a release form sheet, comprising the active energy ray-curable resin composition according to claim 1.