JP7007231B2 - Photocurable adhesive resin composition and adhesive tape using it - Google Patents

Description

The present invention relates to a photocurable pressure-sensitive adhesive resin composition used for temporarily fixing or protecting an adherend, and a pressure-sensitive adhesive tape using the same.

Generally, in the manufacturing process of electronic components, tapes with adhesives are used in various fields. For example, carrier tapes for fixing components when mounting electronic components on printed wiring boards or cutting from silicon wafers to chips. Examples thereof include a dicing tape for fixing the wafer at the time of wiring. These tapes are required to have sufficient adhesive strength when fixing electronic components and wafers, and to be easily peeled off when the need for fixing is eliminated.

As a pressure-sensitive adhesive composition for such applications, for example, a removable pressure-sensitive adhesive composition comprising a water-affinitive acrylic pressure-sensitive adhesive, an active energy ray-curable compound, a photopolymerization initiator, and a cross-linking agent has been proposed (Patent Documents). 1). Further, as a heat-resistant pressure-sensitive adhesive that can withstand high-temperature conditions in the manufacturing process, a heat-resistant temporary-wearing pressure-sensitive adhesive composed of an acrylic polymer having a repeating unit derived from acrylonitrile, an energy ray-polymerizable oligomer, a polymerization initiator, and a cross-linking agent. Etc. have also been proposed (Patent Document 2).

These show strong adhesive strength before being irradiated with energy rays, and while properly fixing and protecting the adherend, when the adhesive layer is cured by irradiating with energy rays, the adhesive strength is reduced and the adherend is adhered. It is possible to facilitate the peeling of the energy. However, these compositions still have high adhesive strength after irradiation with energy rays, and cannot meet the needs for stable and further reduction of adhesive strength, and there is room for improvement.

Japanese Unexamined Patent Publication No. 2000-345131 Japanese Unexamined Patent Publication No. 2012-177084

An object of the present invention is an adhesive resin composition used for an adhesive tape used for temporarily fixing an adherend such as an electronic component or a silicon wafer, and the adherend is provided before photocuring. While it has sufficient initial adhesive strength to hold it, the adhesive strength is significantly reduced by photo-curing, and the adherend can be easily peeled off without adhesive residue. It is an object of the present invention to provide a curable pressure-sensitive adhesive resin composition and a pressure-sensitive adhesive tape using the same.

The invention according to claim 1 is a pressure-sensitive adhesive used for temporarily fixing or protecting an adherend, which is a copolymer (A) composed only of methyl methacrylate and ethyl acrylate, and a polyfunctionality. Provided is a photocurable pressure-sensitive adhesive resin composition comprising (meth) an acrylate monomer (B) and a photopolymerization initiator (C).

The invention according to claim 2 provides the photocurable pressure-sensitive adhesive resin composition according to claim 1, wherein the compounding ratio with respect to the total solid content of the above (A) is 35 to 80% by weight.

The invention according to claim 3 is an adhesive tape obtained by applying the photocurable adhesive resin composition according to claim 1 or 2 on a plastic film, and is a carrier tape or a dicing tape used in a manufacturing process of electronic parts. Provided is an adhesive tape characterized by.

The photocurable pressure-sensitive adhesive resin composition of the present invention is useful as a pressure-sensitive adhesive resin composition used for a pressure-sensitive adhesive tape used for temporarily fixing or protecting an adherend in a manufacturing process of an electronic component.

Hereinafter, the present invention will be described in detail.

The composition of the pressure-sensitive adhesive resin composition of the present invention is a copolymer (A) composed of MMA and EA, a polyfunctional (meth) acrylate monomer (B), and a photopolymerization initiator (C). In addition, in this specification, (meth) acrylate includes both acrylate and methacrylate.

The copolymer (A) used in the present invention is a main polymer constituting a pressure-sensitive adhesive, and has MMA having a high glass transition point (hereinafter Tg) of 105 ° C. and EA having a low Tg of -22 ° C. It is a copolymer. The weight average molecular weight is preferably 50,000 to 300,000, more preferably 100,000 to 200,000. If it is less than 50,000, the cohesive force of the cured product tends to be too low and the film strength tends to be weak, and if it exceeds 300,000, the adhesive strength before photo-curing tends to decrease and the viscosity of the composition tends to increase, resulting in a decrease in workability. The weight average molecular weight (hereinafter referred to as "Mw") was calculated by measuring and calculating the molecular weight in terms of standard polystyrene by a gel permeation chromatography method.

The Tg of (A) is preferably 40 to 60 ° C, more preferably 45 to 55 ° C. If the temperature is lower than 40 ° C., the adhesive strength is strong and adhesive residue tends to be easily generated when peeled off before photo-curing, and if the temperature exceeds 60 ° C., the adhesive strength before photo-curing tends to be weak.

The blending ratio with respect to the total solid content is preferably 35 to 80% by weight, more preferably 40 to 70% by weight. If it is less than 35% by weight, adhesive residue is likely to occur when peeling before photo-curing, and if it exceeds 80% by weight, it is difficult to reduce the peeling strength after photo-curing.

As a commercially available copolymer of MMA and EA, there is Degalan MB319 (trade name: manufactured by Evonik, Tg50 ° C., Mw160000) and the like.

The polyfunctional (meth) acrylate (B) used in the present invention is blended in order to cure the adhesive layer by light irradiation and reduce the peel strength. For example, the bifunctional (meth) acrylate includes (poly) ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, and di (poly) propylene glycol di (meth) acrylate. Propropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, 1.4-butanediol di (meth) acrylate, 4.6-hexanediol di (meth) acrylate, 1.9-nonanediol di (meth) acrylate ) Acrylate, 1.10-decanediol di (meth) acrylate, pentaerythritol di (meth) acrylate, bisphenol A EO modified diacrylate and the like.

Examples of the trifunctional or higher (meth) acrylate include trimethylol propanetri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, isocyanuric acid EO-modified triacrylate, and trimethylolpropanetetra (trimethylol propanetetra (meth) acrylate. Meta) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. may be used alone or in combination of two or more. Can be used in combination. Among these, bisphenol AEO-modified diacrylate, isocyanuric acid EO-modified triacrylate, and dipentaerythritol hexaacrylate, which have good compatibility with (A) and can sufficiently reduce the adhesive strength after photo-curing, are preferable. be.

The (B) may be a polyfunctional photopolymerizable oligomer. For example, polyurethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, polyether (meth) acrylate and the like can be mentioned, and they can be used alone or in combination of two or more.

The photopolymerization initiator (C) used in the present invention generates radicals by irradiation with ultraviolet rays, electron beams, etc., and the radicals trigger a polymerization reaction. 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 as a benzyl ketal system, 1-hydroxy-cyclohexyl-phenyl-ketone and 1- [4- (2- (2-) as an α-hydroxyacetophenone system. Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one is a 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1 as an α-aminoacetophenone system. -On is an acylphosphine oxide system such as 2.4.6-trimethylbenzoyl-diphenyl-phosphinoxide and bis (2.4.6-trimethylbenzoyl) -phenylphosphinoxide, which may be used alone or in combination of two or more. Can be used in combination.

Among these, it is preferable to include an acylfestine oxide system having excellent internal curability. The blending amount is preferably 0.3 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the radically polymerizable component. By blending in this range, the composition can be efficiently cured. Commercially available products include Irgure TPO, 819 (trade name: manufactured by BASF Japan), Omnirad TPO H (manufactured by iGM), and the like.

In addition to the above, the resin composition of the present invention is a leveling agent, an antistatic agent, a tackifier, an antioxidant, a flame retardant, a filler, a colorant, and an antifoaming agent, as required, as long as the performance is not impaired. , Various additives such as a silane coupling agent can be used in combination.

The resin composition of the present invention is used in the form of being dissolved in an organic solvent. The organic solvent used must be highly compatible with the copolymer of MMA and EA, such as aromatics such as benzene, toluene and xylene, and acetate esters such as methyl acetate, ethyl acetate and butyl acetate. , Acetone, methyl ethyl ketone (hereinafter referred to as "MEK"), ketones such as methyl isopropyl ketone and methyl isobutyl ketone, and glycol ethers such as ethylene glycol monobutyl ether and propylene glycol monomethyl ether. Among these, ethyl acetate is preferable in terms of easiness of volatilization. As the blending amount of the organic solvent, an amount of 30 to 70% by weight in solid content is exemplified, but it may exceed this range and may be blended so as to have a viscosity suitable for coating on a film.

The method for applying the resin composition of the present invention is not particularly limited, and is a coating method such as a known spray coat, roll coat, die coat, air knife coat, blade coat, spin coat, reverse coat, gravure coat, wire bar or the like. It can be formed by printing methods such as gravure printing, screen printing, and offset printing. The film thickness to be applied can be exemplified as a cured film thickness of 20 μm to 300 μm, but is preferably 50 μm to 100 μm in order to ensure the drying property of the solvent and the adherend.

Various known plastic films can be used as the base material on which the resin composition of the present invention is applied. For example, polyester film, polyethylene film, polypropylene film, cellophane, diacetylcellulose film, triacetylcellulose film, acetylcellulosebutyrate can be used. Film, Polyvinyl Chloride Film, Vinylidene Chloride Film, Polyvinyl Alcohol Film, Ethylene Vinyl Alcohol Film, Polystyrene Film, Polycarbonate Film, Polymethylpentene Film, Polysulphon Film, Polyether Ether Ketone Film, Polyether Sulphon Film, Polyetherimide Examples thereof include films, polyimide films, fluorine resin films, nylon films, acrylic films, cycloolefin (co) polymer films and the like. Further, the plastic film as the base material may be a single layer or a laminated body having two or more layers. Among these, a polyester-based PET film is suitable from the viewpoint of heat resistance, dimensional stability, translucency, availability, and the like.

The adhesive tape obtained by applying the resin composition of the present invention on a plastic film has a sufficiently high initial adhesive force to an adherend such as an electronic component or a silicon wafer, and when it is cured by irradiating it with light, the adhesive force is significantly reduced. It has a feature that the adherend can be easily peeled off without adhesive residue.

When a PET film having a thickness of 75 μm and glass are laminated via a 75 μm pressure-sensitive adhesive layer made of the resin composition of the present invention, the peeling speed at 25 ° C. after photocuring is 180 ° under the condition of 1000 mm / min. Peeling adhesive strength The peeling strength is preferably 0.1 N / 25 mm or less. Further, it is more preferably 0.08 N / 25 mm or less, and particularly preferably 0.05 N / 25 mm or less from the viewpoint of easy peeling. If it exceeds 0.1 N / 25 mm, adhesive residue is likely to appear when peeled off.

Hereinafter, the present invention will be described in detail based on Examples and Comparative Examples, but only specific examples thereof are shown and the present invention is not particularly limited thereto. Unless otherwise indicated, the measurement was performed under the conditions that the room temperature was 23 ° C. and the relative humidity was 65%.

Examples 1 to 4
Degalan MB319 (trade name: manufactured by Evonik) as a copolymer (A) of PMMA and EA, and DPHA (trade name: dipentaerythritol hexaacrylate manufactured by Nippon Kayaku Co., Ltd.) as a polyfunctional (meth) acrylate (B). And M-315 (trade name: Toa Synthetic, isocyanuric acid EO-modified triacrylate) and BPE-4 (trade name: bisphenol AEO-modified diacrylate manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a photopolymerization initiator (C) in Omnirad. Using TPOH (trade name: iGM, acylphesphine oxide type), dilute with ethyl acetate so that the solid content is 60% by weight in the amount shown in Table 1, and dissolve uniformly using a stirring defoamer. The photocurable pressure-sensitive adhesive resin compositions of Examples 1 to 4 were prepared by stirring up to. The unit of the formulation table is the part by weight.

Comparative Examples 1-9
In addition to the materials used in the examples, Neocry B-818 (trade name: DSM, ethyl methacrylate and ethyl acrylate copolymer), Neocry B-811 (trade name: DSM, polymethyl methacrylate) and Neocry. B-731 (trade name: DSM, polyisobutylmethacrylate, Mw about 55,000) and Degalan LP64 / 11 (trade name: Evonik, copolymer of butyl methacrylate and MMA) and Degalan P675 (trade name: Evonik). , Polyisobutylmethacrylate) and Degalan P26 (trade name: Evonik, polyisobutylmethacrylate) and Degalan LP62 / 05 (trade name: Evonik, copolymer of butylmethacrylate and MMA) and Degalan P24 (trade name:). Using ACMO (trade name: Acryloylmorpholin manufactured by KJ Chemicals Co., Ltd.) as a monofunctional acrylate using a copolymer of butyl methacrylate and MMA manufactured by Evonic, the solid content becomes 60% by weight in the blending amount shown in Table 1. The photocurable pressure-sensitive adhesive resin compositions of Comparative Examples 1 to 9 were prepared by diluting with ethyl acetate and stirring with a stirring defoamer until the mixture was uniformly dissolved.

Table 1

The evaluation method was as follows.

Preparation of evaluation sample A photocurable adhesive resin composition was applied on A4300 (trade name: manufactured by Toyobo Co., Ltd., thickness 75 μm), which is a PET film, so as to have a dry film thickness of 75 μm, and dried at 110 ° C. for 180 seconds. , A release film E7002 (trade name: manufactured by Toyobo Co., Ltd., thickness 50 μm) was laminated to prepare an adhesive sheet. After that, the release film was peeled off and attached to a glass plate having a thickness of 2 mm.

Peeling strength before UV curing: Using an evaluation sample obtained by cutting a PET film to a width of 25 mm, the peel strength of 180 ° was measured at a peeling speed of 1000 mm / min in an environment of 23 ° C. Less than 1N was defined as x.

Peeling strength after UV curing: Using the electrodeless UV irradiation device F300S / LC-6B manufactured by Fusion UV Systems Japan, the PET film was cut to a width of 25 mm under the conditions of H valve, 1300 mW / cm ² , and 300 mJ / cm ² . After irradiating the evaluation sample to photo-cure the adhesive layer, the peel strength was measured under the above conditions, and 0.1 N or less was designated as ◯ and more than 0.1 N was designated as x.

Adhesive residue: Using an evaluation sample after measuring the peel strength, it was visually evaluated whether or not the adhesive adhered to the glass surface side, and the absence of adhesive residue was marked as ◯, and the presence of glue residue was marked as x.

Evaluation results <br /> Table 2

Each of the photocurable pressure-sensitive adhesive resin compositions of Examples gave good results in both evaluation of peel strength and adhesive residue before and after UV curing.

On the other hand, Comparative Example 1 using a monofunctional acrylate had adhesive residue after UV curing, and Comparative Examples 2 to 9 using an acrylic polymer other than the copolymer of MMA and EA had peeling strength or adhesive residue before and after UV curing. There was a problem with any of these, and none of them was suitable for the present invention.

The photocurable pressure-sensitive adhesive resin composition of the present invention is useful as a carrier tape or a dicing tape used in the manufacturing process of electronic components.

Claims (3)

A pressure-sensitive adhesive used to temporarily fix or protect an adherend, which is a copolymer (A) composed only of methyl methacrylate and ethyl acrylate, and a polyfunctional (meth) acrylate monomer (B). A photocurable pressure-sensitive adhesive resin composition comprising the photopolymerization initiator (C) and the photopolymerization initiator (C). The photocurable pressure-sensitive adhesive resin composition according to claim 1, wherein the compounding ratio of the above (A) to the total solid content is 35 to 80% by weight. An adhesive tape obtained by applying the photocurable adhesive resin composition according to claim 1 or 2 onto a plastic film, which is a carrier tape or a dicing tape used in a manufacturing process of electronic components.