JP7066507B2 - 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 performing. 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 re-peelable 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 triblock copolymer (A) composed of methyl methacrylate and butyl acrylate, and many. It contains a functional (meth) acrylate monomer (B) and a photopolymerization initiator (C), and is characterized in that the blending ratio of the above (A) to the total solid content is 30 to 80% by weight. An adhesive resin composition is provided.

The invention according to claim 2 provides the photocurable pressure-sensitive adhesive resin composition according to claim 1, wherein the compounding ratio to the total solid content of the above (B) is 29.7 to 49.5%. do.

The invention according to claim 3 provides the photocurable pressure-sensitive adhesive resin composition according to claim 1 or 2, wherein the (B) contains a trifunctional or higher (meth) acrylate .

The invention according to claim 4 is an adhesive tape obtained by applying the photocurable adhesive resin composition according to any one of claims 1 to 3 on a plastic film, and is a carrier tape or dicing tape used in a manufacturing process of electronic parts. Provided is an adhesive tape characterized by being present.

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 triblock copolymer (A) composed of MMA and BA, a polyfunctional (meth) acrylate monomer (B), and a photopolymerization initiator (C). .. In addition, in this specification, (meth) acrylate includes both acrylate and methacrylate.

The triblock copolymer (A) composed of MMA and BA used in the present invention is a main polymer constituting an adhesive, and is a hard segment composed of P (poly) MMA and soft composed of P (poly) BA. It is composed of segments, and examples thereof include a triblock structure in which both ends of a soft segment are sandwiched between hard segments. Therefore, it has the characteristics of having both the transparency and weather resistance of PMMA and the flexibility and adhesiveness of PBA.

The copolymerization ratio of PMMA in (A) is preferably 20 to 60%, more preferably 25 to 55% by weight so that the adhesive strength before and after photo-curing is appropriate. If the copolymerization ratio of PMMA is less than 20%, the hardness of the cured product becomes too low and the adhesive strength becomes large, and when peeled off, adhesive residue is likely to occur. If it exceeds 60%, the hardness becomes high and the adhesive strength becomes plow. Tends to decrease.

In (A), two or more kinds of copolymers having different PMMA ratios may be used in combination. In that case, the PMMA ratio is a guideline as in the case of using it alone, and the sum of the values obtained by multiplying the PMMA ratio of each of the different copolymers by the content ratio is 20% by weight or more. (For example, when the compounding amount of the PMMA ratio of 50% by weight is 40% and the compounding amount of the PMMA ratio of 30% by weight is 60%, 50% by weight × 0.4 + 30% by weight × 0.6 = 38% by weight. ).

The blending ratio of (A) to the total solid content is preferably 20 to 80% by weight, more preferably 30 to 75% by weight. If it is less than 20% by weight, adhesive residue is likely to occur when peeled before photo-curing, and if it exceeds 80% by weight, it is difficult to reduce the peeling strength after photo-curing.

The weight average molecular weight of (A) is preferably 30,000 to 130,000, more preferably 50,000 to 100,000. If it is less than 30,000, the cohesive force of the cured product is too low and the film strength becomes weak, and if it exceeds 130,000, the viscosity of the composition becomes high and the workability deteriorates. 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.

Commercially available triblock copolymers of MMA and BA include Clarity LA4285, LA2270, LA2250, and LA2140 (trade name: manufactured by Kuraray Co., Ltd.).

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 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, it is preferable to contain a trifunctional or higher functional (meth) acrylate in order to increase the molecular weight and reactivity of the cured product and reduce the peeling strength of the cured film, for example, isocyanuric acid EO-modified bird. Acrylate and dipentaerythritol hexaacrylate are suitable.

The above (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 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 Igacure TPO, 819 (trade name: manufactured by BASF Japan), Omnirad TPO H (manufactured by iGM), and the like.

In addition to the above, the composition may further contain a leveling agent. The leveling agent spreads on the surface of the coating film in the form of a thin film to control the evaporation rate of the solvent and to make the surface tension uniform, repair defects before forming the coating film, and improve the leveling of the surface. There are acrylic type, vinyl type, silicone type, fluorine type and the like, and among these, the silicone type having a high ability to reduce the surface tension is preferable. Of these, a polyether-modified silicone system having a basic structure of polydimethylsiloxane is particularly preferable. Commercially available products include BYK-UV3500 (trade name: Big Chemie, manufactured by Big Chemie, a polyether-modified polydimethylsiloxane containing an acrylic group), TEGO Glide ZG-400 (trade name: manufactured by Evonic, a polyether-modified polydimethylsiloxane) and the like.

The blending amount of the leveling agent is preferably 40% by weight or less, more preferably 30% by weight or less, based on the total solid content. If it exceeds 40% by weight, the cost increases due to excessive blending, and conversely, the appearance deteriorates due to the deterioration of leveling, and the physical properties such as the film strength deteriorate.

In addition to the above, the resin composition of the present invention can be used as an antistatic agent, a tackifier, an antioxidant, a flame retardant, a filler, a colorant, an antifoaming agent, and a silane cup, if necessary, as long as the performance is not impaired. Various additives such as ring agents 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 block copolymer of MMA and BA, such as aromatics such as benzene, toluene and xylene, and acetate esters such as methyl acetate, ethyl acetate and butyl acetate. Classes, acetone, methyl ethyl ketone (hereinafter referred to as "MEK"), methyl isopropyl ketone, methyl isobutyl ketone and other ketones, ethylene glycol monobutyl ether, propylene glycol monomethyl ether (hereinafter referred to as "PGM") and other ethers. Can be done. 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%.

Example 1
Clarity LA2270 (trade name: manufactured by Claret, MMA content: about 40%, Mw: about 80,000) as a triblock copolymer (A) of PMMA and PBA, and DPHA (commodity) as a polyfunctional (meth) acrylate (B). Name: Dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.), Omnirad TPOH (trade name: manufactured by iGM, acylfesfin oxide-based) as the photopolymerization initiator (C), and solidified in the blending amount shown in Table 1. The photocurable pressure-sensitive adhesive resin composition of Example 1 was prepared by diluting with ethyl acetate so that the content was 60% by weight, and stirring with a stirring defoaming machine until the mixture was uniformly dissolved. The unit of the formulation table is the part by weight.

Examples 2-8
In addition to the materials used in Example 1, as (A), clarity LA2140 (trade name: manufactured by Clare, MMA content of about 28%, Mw of about 80,000) and LA4285 (trade name: manufactured by Clare, MMA content of about 80,000) and LA4285 (trade name: manufactured by Clare). 50%, Mw about 70,000), M-315 (trade name: Toa Synthetic, isocyanuric acid EO-modified triacrylate) as (B), BYK-UV3500 (trade name: manufactured by Big Chemie, acrylic group) as a leveling agent. Polyether-modified polydimethylsiloxane) and TEGO Glide ZG-400 (trade name: Polyether-modified polydimethylsiloxane manufactured by Evonic) were used, and ethyl acetate was used so that the solid content was 60% by weight in the blending amount shown in Table 1. The photocurable pressure-sensitive adhesive resin compositions of Examples 2 to 8 were prepared by stirring with a stirring defoamer until the mixture was uniformly dissolved.

Comparative Examples 1 to 5
In addition to the materials used in the examples, as acrylic polymers, Clarity LA1114 (trade name: Claret, Mw about 80,000, diblock structure) and Neocry B-811 (trade name: DSM, polymethylmethacrylate, Mw). Approximately 40,000) and Neocry B-731 (trade name: DSM, polyisobutyl methacrylate, Mw, approximately 55,000) and Degalan P24 (trade name: Evonic, copolymer of butyl methacrylate and methyl methacrylate, Mw, approximately 180000). ) Is used as a monofunctional acrylate, ACMO (trade name: Acryloylmorpholine manufactured by KJ Chemicals Co., Ltd.), diluted with ethyl acetate so that the solid content becomes 60% by weight in the blending amount shown in Table 1, and a stirring defoamer is used. The photocurable adhesive resin compositions of Comparative Examples 1 to 5 were prepared by stirring until they were 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. , E7002 (trade name: manufactured by Toyobo Co., Ltd., thickness 50 μm), which is a release film, 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 in which a PET film was cut to a width of 25 mm, 180 ° peel strength 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 Example 2 using a diblock copolymer of PMMA and PBA could not form a film after drying, and was compared using polymethylmethacrylate. Example 3 and Comparative Example 4 using polyisobutyl methacrylate did not dissolve in ethyl acetate as a solvent, and Comparative Example 5 using a copolymer of butyl methacrylate and methyl methacrylate had weak adhesive strength before UV curing and adhesive residue. None of them were suitable for the present invention.

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

Claims (4)

A pressure-sensitive adhesive used to temporarily fix or protect an adherend, which is a triblock copolymer (A) composed only of methyl methacrylate and butyl acrylate, and a polyfunctional (meth) acrylate monomer (meth). A photocurable pressure-sensitive adhesive resin composition containing B) and a photopolymerization initiator (C), wherein the blending ratio of the above (A) to the total solid content is 30 to 80% by weight. The photocurable pressure-sensitive adhesive resin composition according to claim 1, wherein the compounding ratio of (B) to the total solid content is 29.7 to 49.5%. The photocurable pressure-sensitive adhesive resin composition according to claim 1 or 2, wherein the (B) contains a trifunctional or higher functional (meth) acrylate. An adhesive tape obtained by applying the photocurable adhesive resin composition according to any one of claims 1 to 3 on a plastic film, and is a carrier tape or a dicing tape used in a manufacturing process of electronic components. ..