JP2018009047A - Photocurable resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocurable resin composition, which is a resin composition to be applied on an opaque envelope or the like and cured by active energy rays such as ultraviolet rays so as to wholly or partially process the sheet to be translucent such that a printed matter or a pattern on the base can be seen, and particularly, which has excellent impregnation property and causes little blur even when a drying time after application on the sheet is long.SOLUTION: The photocurable resin composition is a resin composition for a translucent processed sheet obtained by permeating the resin composition in absorptive paper and then cured by active energy rays. The resin composition comprises a polyfunctional acryl-modified oligomer (A), a polyfunctional acryl monomer (B) other than (A), and a photopolymerization initiator (C), and has a viscosity of more than 500 mPa s and equal to or less than 3,000 mPa s at 25°C.SELECTED DRAWING: None

Description

  The present invention is a resin composition that is applied to an opaque envelope or the like, cured with an active energy ray such as ultraviolet rays, and a part or the whole of the paper is processed to be translucent so that the printed matter or pattern of the base can be seen through. In particular, the present invention relates to a photocurable resin composition having excellent permeability and less bleeding even when the drying time is long after application to paper.

    As a technique for impregnating paper with a resin to make it translucent, there is a method of making a paper transparent by impregnating the paper with a photo-ultraviolet curable ink (Patent Document 1). As a composition to be impregnated into the paper, a solvent-free composition containing an ultraviolet polymerization composition containing a polymerizable vinyl oligomer and a photopolymerizable vinyl monomer and an oxidation polymerization composition has been proposed (patent) Reference 2). However, this formulation is not a fast-curing type and contains an oxidative component that is not cured by ultraviolet rays and gradually cures. Therefore, there are problems such as a change in transparency with time, printed matter stains during printing, and blocking when stacked after printing. there were.

As a fast-curing composition that can cope with these problems, it contains a photopolymerizable vinyl oligomer and a photopolymerizable vinyl monomer, and the paper surface temperature after applying the varnish is 100 ° C. to 160 ° C. by irradiation of far infrared rays for 1 to 3 seconds. After that, a method for producing transparent processed paper that is irradiated with ultraviolet rays has been proposed (Patent Document 3). If this method is used, problems due to the curing speed are eliminated, but a far-infrared irradiation device that increases the paper surface temperature in a short time is necessary on the equipment side, and the paper surface temperature is 100 ° C. or higher in terms of manufacturing conditions. Because there are many restrictions such as needing to be

JP 61-41397 Japanese Patent No. 3282019 Patent No. 3676731

  An object of the present invention is to apply a resin composition which is applied to an opaque envelope or the like and cured with an active energy ray such as ultraviolet rays, so that a part of or the entire surface of a sheet is processed to be translucent so that the printed matter or pattern of the base can be seen through. Thus, it is an object of the present invention to provide a photocurable resin composition that is excellent in permeability and has little bleeding even when the drying time is long after application to paper.

  The invention of claim 1 is a resin composition for transparent processed paper obtained by impregnating absorbent paper and then curing with an active energy ray. The polyfunctional acrylic modified oligomer (A) and (A) A photo-curability having a viscosity at 25 ° C. of more than 500 mPa · s and not more than 3,000 mPa · s, comprising a polyfunctional acrylic monomer (B) other than the photopolymerization initiator (C). A resin composition is provided.

Moreover, invention of Claim 2 provides the photocurable resin composition of Claim 1 whose said polyfunctional acrylic modified oligomer (A) is bisphenol A type diacrylate and / or polyester acrylate.

Moreover, invention of Claim 3 is a photocurable property in any one of Claim 1 or 2 whose polyfunctional acrylic monomer (B) other than said (A) is 5 to 10 weight% with respect to the whole composition. A resin composition is provided.

  The photo-curable resin composition of the present invention is applied to an opaque envelope or the like and cured with an active energy ray such as ultraviolet rays, so that a part or the entire surface of the paper is made translucent so that the printed matter or pattern of the base can be seen through. It is useful as a fast-curing photocurable resin composition that is processed and has excellent permeability to paper and little bleeding after coating.

  The composition of the composition of the present invention is a polyfunctional acrylic modified oligomer (A), a polyfunctional acrylic monomer (B) other than (A), and a photopolymerization initiator (C). In the present specification, (meth) acrylate includes both acrylate and methacrylate.

  The polyfunctional acrylic-modified oligomer (A) used in the present invention is a main component having a (meth) acrylate structure and reacting with (B) to form a transparent resin cured film, such as a bisphenol skeleton or a novolak phenol skeleton. There are epoxy acrylates having an aliphatic skeleton, urethane acrylates having an aliphatic skeleton or an aromatic skeleton, polyester acrylates, polybutadiene acrylates, acrylic acrylates, bisphenol type acrylates, and the like, which can be used alone or in combination of two or more. The number of functional groups is preferably 2 to 3 from the viewpoint of curing shrinkage.

  Among these, bisphenol type acrylate and polyester acrylate having a relatively low viscosity are preferable. In particular, ethylene oxide-modified (hereinafter referred to as “EO modification”) bisphenol A diacrylate is particularly preferable because of its high curing rate. The molecular weight is preferably 400 to 3,000, more preferably 480 to 2,000. When the molecular weight is 400 or more, moderate viscosity adjustment is easy, and when it is 3,000 or less, the curing speed is easily controlled. The blending amount of (A) with respect to the total solid content is preferably 75% by weight to 95% by weight, and more preferably 80% by weight to 90% by weight. When it is 75% by weight or more, a viscosity suitable for workability can be secured, and when it is 95% by weight or less, paper is easily impregnated.

  The polyfunctional acrylic monomer (B) other than (A) used in the present invention is a main component that reacts with (A) to form a transparent resin cured film, and promotes permeability to paper, It also plays a role of adjusting the viscosity of the composition. Since it may be dried in a drying furnace after application to paper, it is preferably low volatile from the viewpoint of safety, and the molecular weight is preferably 600 or less. Moreover, it is preferable not to contain a siloxane bond from the viewpoint of permeability to paper.

  Examples of the bifunctional (meth) acrylate include triethylene glycol diacrylate, neopentyl glycol diacrylate, 3-methyl-1.5 pentanediol diacrylate, 1.4-butanediol di (meth) acrylate, 4.6 -Hexanediol di (meth) acrylate, 1.9-nonanediol di (meth) acrylate, neopentyl glycol dimethacrylate, 1.10-decanediol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, diethylene glycol dimethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, and trifunctional (meth) acrylates such as trimethylolpropane tri (meth) acrylate, ethylene oxy Iido-modified trimethylolpropane tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, tris (2-acryloxyethyl) isocyanurate, ε-caprolactone-modified tris (2-acryloxyethyl) isocyanurate, penta There are erythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, and alkyl-modified dipentaerythritol tri (meth) acrylate.

   Further, as the tetrafunctional or higher functional (meth) acrylate, for example, trimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, alkyl-modified dipentaerythritol tetra (meth) There are acrylate, dipentaerythritol penta (meth) acrylate, alkyl-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, etc. Can be used in combination.

  Among these, polyethylene glycol diacrylate (# 300), trimethylolpropane triacrylate, tripropylene glycol diacrylate, dipentaerythritol hexaacrylate and the like having a molecular weight of 600 or less are preferable. The blending amount of (B) with respect to the total solid content is preferably 5% by weight to 10% by weight. If it is less than 5% by weight, the paper impregnation property is lowered and the transparency is difficult to stabilize, and if it exceeds 10% by weight, the volatilization amount in the drying process becomes remarkable, and a part called “white blur” after UV curing. Whitening phenomenon tends to occur.

  The photopolymerization initiator (C) used in the present invention may be a general-purpose photopolymerization initiator because radicals are generated by irradiation with ultraviolet rays or electron beams, and the radicals trigger a polymerization reaction. Specifically, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, 1-hydroxy-cyclohexyl-phenyl -Ketone, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1- [4- (2-hydroxyethoxy)- Phenyl] -2-hydroxy-2-methyl-1-propan-1-one, etc., which can be used alone or in combination of two or more. It is preferable to mix 1 to 10 parts by weight with respect to 100 parts by weight of the radical polymerizable component, and more preferably 4 to 8% by weight.

  In the pressure-sensitive adhesive composition of the present invention, a reactive diluent and a leveling agent, an antifoaming agent, a wetting agent, an anti-blocking agent, an antioxidant, a flame retardant, a polymerization inhibitor, etc. Various additives may be included.

  Examples of the leveling agent include acrylic, vinyl, and silicone types, and a silicone type having a siloxane bond in the molecule that has a high surface tension reducing ability is preferable. By adding a leveling agent, the film thickness after application to paper can be made uniform, and as a result, the amount of penetration into paper can be made uniform, so that transparency after UV curing is stabilized. The blending amount with respect to the total solid content is preferably 0.05% by weight to 3% by weight. BYK-UV3500, BYK-UV3510, and BYK-UV3570 (trade name: manufactured by BYK-Chemie, acrylic group) are used as commercially available leveling agents. Containing polyester-modified polydimethylsiloxane).

The viscosity of the photocurable resin composition of the present invention is greater than 500 mPa · s at 25 ° C. and 3,000 mPa · s or less, and particularly preferably 600 mPa · s to 1,500 mPa · s. Below 500 mPa · s, if the drying time after application of the resin composition is long, the viscosity will be low and the permeability to the substrate will be too good and bleeding will occur more easily. The amount of permeation becomes uneven and the transparency and appearance are not stable. On the other hand, when it exceeds 3,000 mPa · s, the permeability to the substrate is lowered, and it becomes difficult to obtain stable transparency.

The coating method for applying the resin composition of the present invention to a substrate such as paper may be a known coating method such as gravure printing, flexographic printing, screen printing, roll coating, bar coating, blade coating, and the coating amount is paper. In general, in order for paper to have sufficient transparency, a wet thickness of about 30 μm to 50 μm is a standard.

After application of the resin composition, it is preferable to lower the viscosity by increasing the temperature in a drying furnace and promote resin penetration into the substrate. As specific drying conditions, a drying time of about 60 seconds is exemplified in a warm air drying oven at a set temperature of 80 ° C. to 100 ° C. Under these conditions, special equipment such as a far-infrared irradiation device is unnecessary, and the temperature of the paper surface is 100 ° C. or less, so that there is no problem in terms of safety, and a transparent appearance can be stably obtained. Can do.

When the resin composition of the present invention is cured with ultraviolet rays, a known light source such as a high-pressure mercury lamp, metal halide lamp, xenon lamp, or electrodeless discharge lamp is used, and an integrated light amount of, for example, 50 to 1,000 mJ / cm ² is irradiated. And harden.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, a specific example is shown and it does not specifically limit to these. In addition, when there is no description, it measured on the conditions of 25 degreeC relative humidity 65% of room temperature.

Example 1
(A) New Frontier BPE-4 (trade name: manufactured by Daiichi Kogyo Seiyaku Co., Ltd., bifunctional EO-modified bisphenol A type diacrylate), and (B) PE-300 (trade name: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) PEG # 300 Diacrylate), Irgacure 907 and 184 (trade name: manufactured by BASF Japan) as (C), and BYK-UV3570 (trade name: manufactured by BYK-Chemie) as the leveling agent, as shown in Table 1. The resin composition of Example 1 was prepared by mixing and defoaming by mixing until it was uniformly dissolved in a light-shielding bottle.

Examples 2-9
In addition to the materials used in Example 1, (A) New Frontier BPE-20 (trade name: manufactured by Daiichi Kogyo Seiyaku Co., Ltd., bifunctional EO-modified bisphenol A type diacrylate) and PE-44F (trade name: BASF Japan) TMPTA (trade name: manufactured by BASF Japan, trimethylolpropane triacrylate) and DPHA (product) Name: Nippon Kayaku Co., Ltd., dipentaerythritol hexaacrylate) and TPGDA (trade name: manufactured by BASF Japan, tripropylene glycol diacrylate) are mixed in a light-shielding bottle with the formulation shown in Table 1 and dissolved uniformly. Each of the resins in Examples 2 to 9 was stirred and defoamed. The Narubutsu was prepared.

Comparative Examples 1-4
In addition to the materials used in Examples 1 to 9, ACMO (trade name: manufactured by KJ Chemicals, acryloylmorpholine) and HOP-A (trade name: 2-hydroxypropyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.) are used as monofunctional acrylate monomers. Using the formulation shown in Table 1, the mixture was put into a light-shielding bottle and stirred and defoamed until dissolved uniformly to prepare each resin composition of Comparative Examples 1 to 4.

Table 1

The evaluation method was as follows.

Measurement sample A resin composition was applied to a 55 mm × 100 mm area of envelope paper (60 to 70 g / m 2) using a # 22 bar coater, and dried for 1 minute with a 100 ° C. thermostat. Thereafter, an electrodeless UV irradiation apparatus F300S / LC-6B manufactured by Fusion UV Systems Japan was used and cured by ultraviolet irradiation so that the output was 1,300 mW / cm 2 and the integrated light quantity was 50 mJ / cm 2 with an H bulb.

Viscosity: Using a cone plate viscometer RC-550 manufactured by Toki Sangyo Co., Ltd., measured at a cone angle of 3 ° R17.65 at 25 ± 1 ° C and a rotation speed of 10 rpm, more than 500 mPa · s and 3000 mPa · s or less Otherwise, it was set as x.

  Total light transmittance: Measured using a haze guard manufactured by Toyo Seiki Seisakusho in accordance with JISK7361-1, and the evaluation was 75% or more as ◯, and the others as x.

Turbidity: Measured using a haze guard manufactured by Toyo Seiki Seisakusho according to JIS K 7136, and the evaluation was 91% or less as ◯, and the others as x.

Bleeding: When creating a measurement sample, the distance of bleeding from the end of the area coated with a bar coater was measured, and the amount of bleeding was less than 5 mm, and 5 mm or more was rated as x.

The evaluation results are shown in Table 2.
Table 2

As for the photocurable resin composition of an Example, each evaluation result was favorable.

  On the other hand, the comparative example 1 with a small blending amount of (A) has a large blur, the comparative examples 2 and 3 blended with a monofunctional acrylic monomer have a large blur, and the comparative examples 1 and 3 have a low viscosity. Furthermore, the comparative example 4 which does not mix | blend a photocurable monomer has a high viscosity, and the total light transmittance and turbidity are x evaluation, and neither was suitable for this invention.

The present invention is a photo-curable resin composition that is applied to an opaque envelope or the like, cured with an active energy ray such as ultraviolet rays, and processed partially or entirely into a semi-transparent paper so that the printed matter or pattern of the base can be seen through. Useful as a product.

Claims (3)

  It is a resin composition for transparent processed paper obtained by impregnating absorbent paper and then cured by active energy rays. The polyfunctional acrylic modified oligomer (A) and a polyfunctional acrylic monomer other than (A) ( A photocurable resin composition comprising B) and a photopolymerization initiator (C), wherein the composition has a viscosity at 25 ° C. of more than 500 mPa · s and 3,000 mPa · s or less.   The photocurable resin composition according to claim 1, wherein the acrylic-modified oligomer (A) is bisphenol A type diacrylate and / or polyester acrylate. The photocurable resin composition according to claim 1, wherein the polyfunctional acrylic monomer (B) other than (A) is 5% by weight to 10% by weight with respect to the total composition.