JP2020063315A - Ultraviolet curable resin composition - Google Patents

Abstract

To provide: an ultraviolet curable resin composition for temporary adhesion, which allows easy peeling at an adhesion interface and provides a non-sticky interface after peeling; and a laminated sheet using the same.SOLUTION: Provided is an ultraviolet curable resin composition for temporary adhesion, comprising: an urethane (meth)acrylate (A), a (meth)acrylate monomer (B), polydimethylsiloxane (C), and a photoinitiator (D), where a proportion of the (meth)acrylate in (B) having a polar group and/or a polar skeleton is 35 wt.% or more. Also provided is a laminated sheet using the same.SELECTED DRAWING: None

Description

  TECHNICAL FIELD The present invention relates to an ultraviolet curable resin composition for temporary adhesion, which is suitable for laminating a laminated sheet or the like typified by an information carrying sheet.

  Conventionally, a sealed letter has been used to send the information in the concealed state, but now, the information can be written on the inside of the V-shaped or Z-shaped postcard and then adhered, and the concealed state can be mailed. Postcards have come to be used, and these are generally referred to as information carrying sheets.

  In the past, the applicant has invented a composition comprising a vinyl acetate emulsion, a plasticizer and calcium fatty acid as an adhesive that can be used for an information carrying sheet (Patent Document 1). The present invention was excellent in that it had a good releasability and that the information surface did not remain sticky after the peeling. However, since it is a water-based adhesive, there is a problem in that it requires drying and curing after application.

On the other hand, as an adhesive capable of coping with such problems, an ultraviolet curing resin composed of an acrylic oligomer having a specified molecular weight and structure, two or more kinds of acrylic photopolymerizable monomers, and a photopolymerization initiator is proposed (Patent Document 2). This composition is used by a method in which a resin is applied to a base material, then the resin is photocured, and after the composition is cured, the surfaces to be coated are stuck together and pressed. On the other hand, when using a translucent base material for lamination without applying pressure, that is, after curing the resin applied to one of the base materials, the resin applied to one of the base materials is not applied. When the resin surfaces were attached to each other in a cured state and then light-cured to be laminated, the attachment interface was solidified and could not be peeled off. Therefore, there is room for improvement when such a resin is pasted before being cured and then is photocured.

Japanese Patent No. 5008934 Japanese Patent No. 4422820

  An object of the present invention is to provide a UV-curable resin composition for temporary adhesion that can be used for a laminated sheet typified by an information carrying sheet, is easy to peel at an adhesive interface, and has a non-sticky interface after peeling. To provide.

  The invention of claim 1 is a urethane (meth) acrylate (A) having a polytetramethylene glycol skeleton, a (meth) acrylate monomer (B), a polydimethylsiloxane (C), a photopolymerization initiator (D), And a ratio of (meth) acrylate having a polar skeleton and / or a polar skeleton in (B) is 35% by weight or more, and an ultraviolet curable resin composition for temporary adhesion is provided.

Further, the invention of claim 2 is characterized in that the (B) polar group or / and (meth) acrylate having a polar skeleton has any one of a hydroxyl group, an amide bond and a polyether skeleton. An ultraviolet curable resin composition is provided.

The invention of claim 3 provides a laminate sheet using the ultraviolet curable resin composition for temporary adhesion according to claim 1 or 2.

Further, in the invention of claim 4, the ultraviolet curable resin is applied to one of the two base materials, at least one of which is transparent, and cured, and then the ultraviolet curable resin is applied to one of the base materials, and then the resin is applied. The ultraviolet-curable resin composition is the ultraviolet-curable resin composition for temporary adhesion according to claim 1 or 2, wherein the coated surfaces are adhered to each other, and the translucent substrate surface is irradiated with ultraviolet rays for temporary adhesion. A method for manufacturing a laminated sheet is provided.

The composition of the present invention is a UV-curable resin composition for temporary adhesion that is easy to peel off at the adhesive interface and does not stick to the interface after peeling, and is used as an adhesive for a laminate sheet typified by an information carrying sheet. Is useful as

The composition of the ultraviolet curable resin composition of the present invention is urethane (meth) acrylate (A), (meth) acrylate monomer (B), polydimethylsiloxane (C), and photopolymerization initiator (D). In addition, in this specification, (meth) acrylate includes both acrylate and methacrylate.

The urethane (meth) acrylate (A) used in the present invention is one of the main components constituting the cured film and has a polytetramethylene glycol (hereinafter referred to as PTMG) skeleton which is excellent in abrasion resistance and flexibility at low temperature. It is a photoreactive resin. The number of (meth) acryloyl groups is preferably 2 to 6, and more preferably 2 to 4. For example, in the case of a bifunctional urethane (meth) acrylate, a compound obtained by subjecting PTMG and a diisocyanate to an addition reaction with a monofunctional (meth) acrylate having a hydroxyl group to undergo a condensation reaction is a tetrafunctional urethane (meth) acrylate. In the case of acrylate, the reaction product of PTMG and diisocyanate can be exemplified by condensation reaction of bifunctional (meth) acrylate having a hydroxyl group.

The weight average molecular weight (hereinafter Mw) of (A) is preferably 1,000 to 30,000, more preferably 1,500 to 10,000, and particularly preferably 2,000 to 6,000. When it is 1,000 or more, a sufficient cohesive force can be secured, and when it is 30,000 or less, the viscosity can be easily controlled and can be easily controlled. In addition, Mw was measured and calculated by gel permeation chromatography, using a column using a packing material of a styrenedivinylbenzene base material and using a tetrahydrofuran eluent as an eluent to measure a standard polystyrene.

The compounding amount of (A) with respect to the entire composition is preferably 15 to 60% by weight, more preferably 18 to 55% by weight. When the amount is 15% by weight or more, a sufficient cohesive force can be secured, and when the amount is 60% by weight or less, the viscosity can be easily controlled to be easy to handle.

The (meth) acrylate monomer (B) used in the present invention is a main component constituting a cured film as in the case of (A), and is added as a diluent for improving curability and a reactive diluent. In particular, in terms of good compatibility with (A), it is preferable to have a polar group or / and a polar skeleton, and at least the blending ratio thereof in (B) is 35% by weight or more, preferably 40% by weight or more. More preferably 45% by weight or more. If it is less than 35%, the compatibility with (A) is lowered to cause whitening, and the viscosity is increased to deteriorate the coating property, which is not possible.

Examples of the polar group and / or polar skeleton (B) include a hydroxyl group, an amide bond, and an ether skeleton. Specific examples of the (B) having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and 6 -Hydroxyhexyl (meth) acrylate, pentaerythritol tri (meth) acrylate, and dipentaerythritol tetra (meth) acrylate are specifically (meth) acrylamide and N, N-dimethyl as (B) having an amide bond. There are (meth) acrylamide, N, N-diethyl (meth) acrylamide, hydroxyethylacrylamide, acryloylmorpholine and the like, which can be used alone or in combination of two or more kinds. Among these, 4-hydroxybutyl acrylate (hereinafter 4-HBA) in view of low viscosity and compatibility with (A), and acryloylmorpholine having low skin irritation and low vapor pressure are particularly preferable.

Specific examples of (B) having a polyether skeleton include polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and polytetramethylene glycol di (meth) acrylate, which may be used alone or in combination of two or more. Can be used in combination. Among these, polytetramethylene glycol diacrylate is particularly preferable in terms of high cohesive strength of the cured product.

The amount of the compound (B) to be blended with respect to the whole composition is preferably 30 to 75% by weight, more preferably 35 to 72% by weight. When it is 30% by weight or more, sufficient curability can be secured, and when it is 75% by weight or less, it becomes possible to control the viscosity suitable for workability.

  The polydimethylsiloxane (C) used in the present invention is blended so as to reduce the adhesiveness between cured coatings and facilitate interfacial peeling, and at the same time suppress the tackiness of the peeled interface. The side chain or main chain of (C) may be modified, and examples thereof include polyether modification and polyester modification, and these can be used alone or in combination of two or more kinds. Among these, polyethylene oxide modification and polyester modification are particularly preferable because the polarity of the molecule can be increased to improve the compatibility with (A). When it has an acrylic functional group in the molecule, it can react with (A) and (B) to incorporate (C) into the polymer.

The compounding amount of (C) with respect to the entire composition is preferably 0.1 to 12% by weight, and more preferably 0.5 to 10% by weight. When the amount is 0.1% by weight or more, sufficient releasability can be secured, and when the amount is 12% by weight or less, sufficient curability can be secured. Examples of commercially available polydimethylsiloxane (C) include BYK-UV3500, BYK-UV3570 (trade name: manufactured by Big Chem Japan), TEGO Glide ZG400 (trade name: manufactured by Evonik), and the like.

  The photopolymerization initiator (D) used in the present invention generates a radical upon irradiation with ultraviolet rays or electron beams, and the radical triggers the polymerization reaction. Benzyl ketal-based, acetophenone-based, phosphine oxide-based For example, a general-purpose photopolymerization initiator can be used. By arbitrarily selecting the light absorption wavelength of the polymerization initiator, curability can be imparted over a wide wavelength range from the ultraviolet region to the visible light region. Specifically, 2.2-dimethoxy-1.2-diphenylethan-1-one is used as a benzyl ketal system, and 1-hydroxy-cyclohexyl-phenyl-ketone and 1- [4- (2- Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one is used as 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1 as α-aminoacetophenone system. -One has 2.4.6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2.4.6-trimethylbenzoyl) -phenylphosphine oxide as an acylphosphine oxide system, and they may be used alone or in combination of two or more. Can be used in combination. Among these, it is preferable to contain an α-hydroxyacetophenone system that does not easily yellow, and commercially available products include Irgacure 184 (trade name: manufactured by BASF Japan), Omnirad 184 (trade name: manufactured by iGM), and the like.

The blending amount of the above (D) is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the photocuring component, and 3 to 8
More preferably parts by weight. By blending within this range, the composition can be efficiently cured.

The composition of the present invention contains a plasticizer, an antioxidant pigment, a dye, a light stabilizer, a photosensitizer, a defoaming agent, a thickener, an ultraviolet absorber, an inorganic filler, if necessary, within a range that does not impair the performance. Various additives such as organic fine particles and wettability adjusting agent may be contained.

The method of using the present invention in a laminated sheet is carried out by applying the resin composition of the present invention to one of two base materials, at least one of which is translucent, and photo-curing the same, and then applying the resin to one of the base materials in the same manner. The composition is applied, and then the resin-applied surfaces are attached to each other, and ultraviolet rays are irradiated from the light-transmitting base material surface to integrally cure the resin. With this method, the pressurizing step after bonding, which is conventionally required, is unnecessary, and the laminating process can be easily performed.

Examples of the substrate used in the present invention include paper, wood, cloth, metal foil, plastic film, plastic sheet, plastic laminated paper, and plastic laminated cloth. At least one of the substrates to be laminated is transparent. Must. Examples of the translucent plastic sheet include polyethylene, polypropylene, polyethylene terephthalate, and polyvinyl chloride, but the translucent plastic sheet is not limited to plastic as long as it has translucency.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, which are specific examples and are not particularly limited thereto. Unless otherwise noted, room temperature was measured at 25 ° C. and 65% relative humidity. Moreover, the compounding quantity shows a weight part.

Example 1
In the light-shielding bottle, SUA-023 (trade name: manufactured by Asia Kogyo Co., Ltd., PTMG skeleton urethane acrylate, bifunctional, Mw2600) is used as the (A), and ACMO (trade name: manufactured by KJ Chemicals) as the polar monomer of the (B). , Acryloylmorpholine), NOAA (trade name: manufactured by Osaka Organic Chemical Industry, normal octyl acrylate) as a non-polar monomer, and TEGOGlide ZG-400 (trade name: manufactured by Evonik, polyether-modified poly) as the (C). As a photopolymerization initiator (D), Omnirad 184 (trade name: 1-hydroxycyclohexylketone, manufactured by iGM) was added in an amount shown in Table 1, and the mixture was stirred using a stirring and defoaming machine until uniform. The resin composition of Example 1 was prepared.

Examples 2-10
In addition to the materials used in Example 1, SX56-21 (trade name: Asia Kogyo, PTMG skeleton urethane acrylate, tetrafunctional, Mw4300) is used as the (A), and 4-HBA (product is used as the polar monomer of the (B). Name: Osaka Organic Chemical Industry Co., Ltd., 4-hydroxybutyl acrylate) and M-240 (trade name: Toa Gosei Co., PEG # 200 diacrylate) are light acrylate LA (trade name: Kyoeisha) as non-polar monomers. BYK-UV3570 (trade name: acrylic group-containing polyester modified polydimethylsiloxane) and BYK-UV3500 (trade name: acrylic group-containing polyether modified polydimethylsiloxane) as the (C). Using the composition shown in Table 1 and stirring with a stirring defoamer until uniform The resin compositions of Examples 2-10 were prepared.

Comparative Examples 1-5
In addition to the materials used in the examples, RUA-051 (trade name: trifunctional manufactured by Asia Kogyo Co., Ltd.) as an isocyanurate urethane acrylate and ISTA (trade name: manufactured by Osaka Organic Chemical Industry Co., Ltd., isostearyl) as a non-polar monomer. Acrylate) was used to prepare resin compositions of Comparative Examples 1 to 5 by using a stirring and defoaming machine with the composition shown in Table 1 and stirring until uniform.

Table 1

The evaluation method was as follows.

  Viscosity: E-type viscometer RE-215R manufactured by Toki Sangyo Co., Ltd. was used to measure 25 ± 1 ° C. at a cone angle of 3 ° R17.65, a rotation speed of 500 mPs · s or less at 10 rpm, and a measurement of more than 500 mPs · s at 20 rpm.

  Curability: The ultraviolet curable resin composition is applied to a PET film A4300 (trade name: manufactured by Toyobo Co., Ltd., thickness: 75 μm) so that the film thickness is 10 μm, and a fusion UV system Japan electrodeless UV irradiation device F300S / Using LC-6B, UV curing was performed with an H bulb at an output of 1300 mW / cm2 and an integrated light amount of 300 mJ / cm2, and then the surface was not tacky and the stickiness was confirmed.

  Total light transmittance: Based on JISK7361-1, measured using a haze meter Haze-gard2 manufactured by Toyo Seiki Seisaku-sho, Ltd., and 91% or more was evaluated as O and less than 91% was evaluated as X. The measurement sample used was the same as the sample used in the above-mentioned evaluation of curability.

  Haze: Measured using a haze meter Haze-gard2 manufactured by Toyo Seiki Seisakusho according to JIS K7361-1, and evaluated as 1% or less and 1% or more as x. The measurement sample used was the same as the sample used in the above-mentioned evaluation of curability.

  Peel strength: PET film A4300 (trade name: manufactured by Toyobo Co., Ltd., thickness: 75 μm) was applied to have a film thickness of 10 μm, and after being bonded to the sample used in the above curability evaluation, it was manufactured by Fusion UV System Japan. Using an electrodeless UV irradiation device F300S / LC-6B, UV curing was performed with an H bulb at an output of 1300 mW / cm 2 and an integrated light amount of 300 mJ / cm 2. The cured sample was cut into a size of 150 * 25 mm. Using a tensile tester TGI-1kN manufactured by Techno Graph, a crosshead speed of 300 mm / min. The T-shaped peel strength at an environmental temperature of 23 ° C. was measured, and when the peel strength was 10 N / 25 mm or more due to material destruction, the adhesion surfaces were interfacially peeled with a peel strength of 0.1 to 10 N / 25 mm. The case was marked as ○.

Table 2 shows the evaluation results of the examples.
Table 2

  The resin compositions of Examples had good curability, total light transmittance, haze, and peel strength.

 On the other hand, Comparative Example 1 in which (C) is not blended cannot be peeled off, and the ratio of polar monomers in (B) is low, or Comparative Examples 2 to 4 which are not blended have low compatibility and the liquid is whitened and is not a PTMG skeleton. Comparative Example 5 containing urethane acrylate was also whitened, and none of them was suitable for the present invention.

The composition of the present invention is a UV-curable resin composition for temporary adhesion that is easy to peel off at the adhesive interface and does not stick to the interface after peeling, and is used as an adhesive for a laminate sheet typified by an information carrying sheet. Is useful as

Claims (4)

  A urethane (meth) acrylate (A) having a polytetramethylene glycol skeleton, a (meth) acrylate monomer (B), a polydimethylsiloxane (C), and a photopolymerization initiator (D) are contained, and in (B) A ratio of (meth) acrylate having a polar group and / or a polar skeleton is 35% by weight or more, and a UV-curable resin composition for temporary adhesion.   A UV-curable resin composition for temporary adhesion, wherein the (B) polar group or / and (meth) acrylate having a polar skeleton has any of a hydroxyl group, an amide bond and a polyether skeleton. A laminate sheet using the ultraviolet curable resin for temporary adhesion according to claim 1 or 2. At least one of the two translucent base materials is coated with an ultraviolet curable resin and cured, and then one of the base materials is coated with the ultraviolet curable resin, and then the resin-coated surfaces are adhered to each other to transmit light. A method for producing a laminate sheet, wherein the ultraviolet curable resin is the ultraviolet curable resin composition for temporary adhesion according to claim 1 or 2, wherein the ultraviolet curable resin is temporarily adhered by being irradiated with ultraviolet rays from the surface of the substrate.