TW201936855A - Photocurable adhesive composition and adhesive sheet - Google Patents

Abstract

The present invention provides a photocurable adhesive composition that has excellent heat resistance (flocculating property) without leaving an adhesive residue on adherends even when heat treatment is performed, and also makes it possible to obtain an adhesive sheet excellent in storability during storage. The photocurable adhesive composition of the present invention comprises a (meth)acrylic polymer and a photopolymerization initiator, and after a photocurable adhesive layer formed from the photocurable adhesive composition has been cured by energy beam irradiation, the tensile storage elastic modulus (E') at 25 DEG C is 3.0 * 107 to 2.0 * 109 Pa, the tensile storage elastic modulus (E') at 100 DEG C is 1.0 * 107 Pa or less, and the tensile storage elastic modulus (E') at 260 DEG C is 1.0 * 106 Pa or more.

Description

Photocurable adhesive composition and adhesive sheet

The present invention relates to a photocurable adhesive composition and an adhesive sheet, and more particularly to a photocurable adhesive composition and use thereof for a surface protective sheet (film) suitable for use as an electronic material member. An adhesive sheet of the photocurable adhesive composition.

In order to protect metal plates containing copper, aluminum, silver, stainless steel, etc., glass plates, including epoxy resin, polyimide resin, polyester resin, glass epoxy prepreg such as FR-4, solder resist ( Resin sheets such as solder resists, and such composite sheets and printed wiring boards including such members, integrated circuit (IC) wafers, semiconductor devices, package substrates, lead frames, and the like Or use a surface protection sheet for temporary fixing. The surface protection sheet is an adhesive sheet having an adhesive layer and a base material layer, and is adhered to the product substrate at the time of manufacture of the product, and is peeled off at a predetermined time.

In addition, in the printed wiring board, the electronic component is mounted by solder, and the part which protects against the influence of solder flux during solder reflow processing is shielded by the adhesive sheet, and the electronic component is shielded. The solder is reflow soldered to a prescribed circuit (solder reflow step), and the adhesive sheet is peeled off after the solder reflow step.

Further, in the semiconductor device, when the IC chip is mounted on the circuit board, first, the circuit board is bonded to the adhesive sheet in advance, and after the IC chip is mounted on the circuit board, the IC chip is sealed by a sealing material such as epoxy resin. Sealing (molding step), and after the molding step, the adhesive sheet is peeled off, whereby an IC wafer mounting substrate on which an IC wafer is mounted on a circuit substrate is obtained.

As the adhesive composition used in such an adhesive sheet, various studies have been made since the prior art. For example, Patent Document 1 proposes an adhesive composition comprising (A) an acrylic adhesive compound having a mass average molecular weight of 600,000 or more, an acid value of 5 mgKOH/g or more, and less than 30 mgKOH/g, and (B) The epoxy-based crosslinking agent exhibits an elastic modulus of 0.3×10 ⁶ Pa to 3×10 ⁶ Pa and an adhesion force of 0.1 N/25 mm or more in the entire temperature range of 23° C. to 260° C., and at 23° C. The ratio (X)/(Y) of the modulus of elasticity (X) to the modulus of elasticity (Y) at 260 ° C is in the range of 0.4 to 3.2. Further, Patent Document 2 proposes an adhesive composition containing a first acrylic block copolymer containing a methacrylic acid block and an acrylic block, and a second acrylic system containing no methacrylic acid block. a block copolymer or an acrylic non-block polymer, the total of the first acrylic block copolymer with respect to the first acrylic block copolymer, the second acrylic block copolymer, and the acrylic non-block polymer The content ratio of the mass is 10% by mass or more, the storage elastic modulus at 20 ° C is 5 MPa or more, the storage elastic modulus at 140 ° C is 5 MPa or less, and the ratio of the storage elastic modulus at 20 ° C to the storage elastic modulus at 140 ° C is 2 the above.
[Prior Art Literature]
[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open Publication No. 2010-155933, Patent Document 2: Japanese Patent Laid-Open No. 2015-221885

[Problems to be solved by the invention]
As described above, the adhesive sheet used for the surface protection of the electronic material member requires excellent heat resistance (cohesiveness) when the heat such as the solder reflow step or the molding step is applied, and the heat resistance of the adhesive sheet is low. In the case of the case (without cohesiveness), the adhesive composition is eluted by heating, and the adhesive remains on the product side when the adhesive sheet is peeled off. Further, in the solder reflow step, it is heated at about 260 ° C for several tens of seconds, and in the molding step, it is heated at about 170 ° C to 180 ° C for 5 hours to 7 hours. Therefore, heat resistance which can withstand a high temperature of 100 ° C or higher is required.

On the other hand, the surface of the base material layer in the adhesive sheet is not only flat, but also has a concave-convex portion or a concave-convex shape, and therefore the followability of the adhesive layer and the base material layer is also required. The adhesive sheet using the adhesive composition of the patent document 1 and the patent document 2 is a thermal-hardening reaction previously considering the normal temperature preservability. Therefore, there is a problem that the followability is insufficient, and there is a problem that a gap is formed between the unevenness of the surface of the base material layer and the contact portion of the adhesive layer.

Therefore, an object of the present invention is to provide a resin having excellent heat resistance (cohesiveness) without remaining in the adherend during heat treatment, and to obtain excellent followability to the substrate layer during storage. A photocurable adhesive composition containing an adhesive sheet excellent in stability and an adhesive sheet using the photocurable adhesive composition. Hereinafter, heat resistance (cohesiveness) is simply referred to as heat resistance.
[Means for solving the problem]

The inventors of the present invention have made an effort to solve the problem, and have found that a photocurable resin composition which can be cured by energy ray irradiation is used, and is cured. The viscoelasticity (tensile storage elastic modulus (E')) is a hardness within a predetermined range, and the above problems can be solved, thereby completing the present invention.

That is, the present invention is characterized by the following (1) to (12).
(1) A photocurable adhesive composition which is a photocurable adhesive composition curable by irradiation with an energy ray, comprising a (meth)acrylic polymer and a photopolymerization initiator After the curing by the energy ray, the photocurable adhesive layer formed of the photocurable adhesive composition is cured, and the tensile storage elastic modulus (E') at 25 ° C is 3.0 × 10 ⁷ Pa - The tensile storage elastic modulus (E') at 2.0 × 10 ⁹ Pa at 100 ° C was 1.0 × 10 ⁷ Pa or less, and the tensile storage elastic modulus (E') at 260 ° C was 1.0 × 10 ⁶ Pa or more.
(2) The photocurable adhesive composition according to the above (1), wherein the photocurable adhesive layer has a tensile storage elastic modulus at 25 ° C before curing by energy ray irradiation (E) ') is 1.0 × 10 ⁶ Pa to 9.0 × 10 ⁸ Pa.
The photocurable adhesive composition according to the above aspect (1), wherein the (meth)acrylic polymer has a glass transition temperature of from 0 ° C to 50 ° C.
The photocurable adhesive composition according to any one of the above aspects, wherein the (meth)acrylic polymer has a weight average molecular weight of 50,000 to 500,000.
The photocurable adhesive composition according to any one of the above (1), wherein the (meth)acrylic polymer has a double bond equivalent of 1,000 g/eq to 5,000. g/eq.
(6) A photocurable adhesive layer which is formed of the photocurable adhesive composition according to any one of the above (1) to (5).
(7) An adhesive sheet comprising the photocurable adhesive layer according to (6) above.
(8) An adhesive layer which is a photocurable adhesive formed of the photocurable adhesive composition according to any one of the above (1) to (5), which is irradiated with an energy ray. The layer is hardened.
(9) An adhesive sheet comprising the adhesive layer as described in (8) above.
(10) The adhesive sheet according to (9), which has releasability.
(11) The adhesive sheet according to (9) or (10), which is used as a surface protection sheet for an electronic material member.
(12) An electronic material member in which the adhesive sheet of (11) is attached.
[Effects of the Invention]

Since the photocurable adhesive composition of the present invention has excellent heat resistance, when it is adhered to the adherend as an adhesive sheet and is subjected to high-temperature heat treatment at 100 ° C or higher, the adhesive does not remain in the adhesive. Sticky body.
Further, since the photocurable adhesive composition of the present invention is cured by irradiation with a light energy ray, when it is stored in a state of shielding the light energy ray, the physical properties do not change during storage at room temperature. In this way, the adhesive layer formed of the photocurable adhesive composition of the present invention exhibits excellent followability (embedability) for the base material layer having irregularities, and an adhesive sheet excellent in storage stability can be obtained.
Thus, the photocurable adhesive composition of the present invention and the adhesive sheet using the photocurable adhesive composition are attached to the integrated circuit (IC) wafer when the printed wiring board is manufactured or the substrate is molded by resin. It is effective for bonding the substrate.

Hereinafter, the form for carrying out the invention (hereinafter referred to as "this embodiment") will be described in detail. The present invention is not limited to the following embodiments, and various modifications may be made without departing from the spirit and scope of the invention.

In the present specification, the term "sheet" means a film and a sheet as defined by Japanese Industrial Standards (JIS) K 6900:1994. According to the definition in JIS K 6900:1994, the term "film" refers to a thin flat product which is extremely small in thickness and width and arbitrarily defines the maximum thickness, and is supplied in the form of a usual roll. A flat article that is thin and whose thickness is generally small in the ratio of length to width. The boundary between the film and the sheet is not certain, and the concept of a film is also considered to be included in the sheet.
In addition, in the present specification, the "substrate" of the substrate layer means a material for forming an adhesive layer on the surface thereof, and is a natural or synthetic support, and also includes a base carrier material and a reinforcing material. material.

Further, in the present specification, the term "(meth)acrylic acid means acrylic acid or methacrylic acid, the term "(meth)acryl fluorenyl group means acryl fluorenyl group or methacryl fluorenyl group, and the so-called (meth) acrylate means acrylic acid. Ester or methacrylate.
In addition, in this manual, "quality" has the same meaning as "weight".

The photocurable adhesive composition of the present embodiment is a resin composition which can be cured by irradiation with an energy ray, and contains at least a (meth)acrylic polymer and a photopolymerization initiator. The photocurable adhesive composition of the present embodiment is characterized in that the photocurable adhesive layer formed of the photocurable adhesive composition is cured by energy ray irradiation, and is cured at 25 ° C. The tensile storage elastic modulus (E') is 3.0 × 10 ⁷ Pa to 2.0 × 10 ⁹ Pa, and the tensile storage elastic modulus (E') at 100 ° C is 1.0 × 10 ⁷ Pa or less, and stretching at 260 ° C. The storage elastic modulus (E') was 1.0 × 10 ⁶ Pa or more.
Each component will be described below.

<(Meth)acrylic polymer>
The (meth)acrylic polymer is a polymer containing one or two or more (meth)acrylic compounds as main monomer units.

Examples of the (meth)acrylic compound constituting the (meth)acrylic polymer include (meth)acrylic acid; (meth)acrylic acid decylamine; (meth)acryl hydrazinomorpholine; (methyl) Methyl acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate, ( N-hexyl methacrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, (methyl) The carbon number of the alkyl group such as lauryl acrylate (n-lauryl (meth) acrylate), isomyristyl (meth) acrylate, stearyl (meth) acrylate or isostearyl acrylate is 1 ～ 18 (meth)acrylic acid alkyl ester; acrylonitrile; glycidyl methacrylate; alkenyl (meth)acrylate having a carbon number of 2 to 18, such as 3-butenyl (meth)acrylate (meth) acrylate having an aromatic ring such as benzyl (meth) acrylate or phenoxyethyl (meth) acrylate; methoxytetraethylene glycol (meth) acrylate, methoxy hexaethyl Glycol (Meth) acrylate, methoxy octaethylene glycol (meth) acrylate, methoxy pentylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, A Oxygen heptapropanediol (meth) acrylate, ethoxytetraethylene glycol (meth) acrylate, butoxyethylene glycol (meth) acrylate, butoxy diethylene glycol (meth) acrylate An alkoxy polyalkylene glycol (meth) acrylate such as ester; cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentyl (meth) acrylate, etc. having an alicyclic group (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. ; (meth)acrylic acid tetrahydrofurfuryl ester; (meth)acrylic acid N,N-dimethylaminoethyl ester, N,N-dimethylaminopropyl (meth) acrylamide, N, N-Dimethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-hydroxyethyl (methyl) (Meth) acrylamide derivatives such as acrylamide; 2-(2-methylpropenyloxyethyloxy)ethyl (meth) acrylate having isocyanate group such as isocyanate or 2-(meth) propylene methoxyethyl isocyanate; tetraethylene glycol mono (meth) acrylate, hexaethylene glycol mono (meth) acrylate , polypropylene glycol mono(methyl) such as octapropylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, tripropylene glycol mono(meth)acrylate, octapropylene glycol mono(meth)acrylate An acrylate, a (meth) acrylate having a siloxane skeleton, or the like.
Among them, from the viewpoint of heat resistance at the time of high-temperature heating and peeling without residue, a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms, acrylonitrile, and methacrylic acid shrinkage is preferred. The glyceride is more preferably (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, acrylonitrile or glycidyl methacrylate.

The (meth)acrylic polymer may be a homopolymer including one selected from the above (meth)acrylic compounds, or may be a copolymer containing two or more kinds. Further, the (meth)acrylic polymer may be an addition of an arbitrary (meth)acrylic compound to a homopolymer or a copolymer containing at least one selected from the (meth)acrylic compounds. Form a polymer. Examples of the (meth)acrylic compound to be added include glycidyl methacrylate.

The (meth)acrylic polymer may contain a compound copolymerizable with the (meth)acrylic acid derivative as a comonomer. Specific examples thereof include styrene, 4-methylstyrene, vinylpyridine, vinylpyrrolidone, vinyl acetate, cyclohexylmaleimide, phenylmaleimide, and Malay. Anhydride, etc.

The weight average molecular weight (Mw) of the (meth)acrylic polymer is preferably from 50,000 to 500,000. When the weight average molecular weight of the (meth)acrylic polymer is 50,000 or more, the film formability at the time of forming an adhesive sheet can be favorably maintained. Further, when the weight average molecular weight is 500,000 or less, the followability at the time of bonding to the base material layer can be favorably maintained. The lower limit of the weight average molecular weight is more preferably 75,000 or more, further preferably 100,000 or more, and the upper limit is more preferably 450,000 or less, and still more preferably 400,000 or less.

Here, the weight average molecular weight means a value measured by gel permeation chromatography (GPC) using standard polystyrene having an average molecular weight of from about 500 to about 1,000,000.

The ease of occurrence of the energy ray hardening depends on the amount of the ethylenically unsaturated double bond in the photocurable adhesive composition, and can be expressed by the "double bond equivalent" of the (meth)acrylic polymer.
The double bond equivalent of the (meth)acrylic polymer is preferably from 1,000 g/eq to 5,000 g/eq. When the double bond equivalent of the (meth)acrylic polymer is 5,000 g/eq or less, the photocurable adhesive composition is sufficiently cured when the energy ray is irradiated, and heat resistance at the time of high-temperature heating can be obtained. When it is 1,000 g/eq or more, the adhesion to the product substrate can be favorably maintained, and heat resistance at the time of high-temperature heating can be obtained. The lower limit of the double bond equivalent is more preferably 1,500 g/eq or more, further preferably 2,000 g/eq or more, and the upper limit is more preferably 4,500 g/eq or less, and further preferably 4,000 g/eq or less.

Here, the double bond equivalent is a value calculated by the mass (g) of the (meth)acrylic polymer/the double bond of the (meth)acrylic polymer containing the number of moles.

The glass transition temperature (Tg) of the (meth)acrylic polymer is preferably from 0 ° C to 50 ° C. When the glass transition temperature of the (meth)acrylic polymer is 0° C. or more, it can be peeled off without residual glue after heating at a high temperature, and if it is 50° C. or less, the followability to the base layer becomes good. The lower limit of the glass transition temperature is more preferably 5 ° C or higher, more preferably 10 ° C or higher, and the upper limit is more preferably 45 ° C or lower, and further preferably 40 ° C or lower.

Here, the glass transition temperature means a value measured by dynamic viscoelasticity measurement (dynamic mechanical analysis (DMA)).

<Photopolymerization initiator>
The photopolymerization initiator is a component that promotes a hardening reaction by irradiation of an energy ray. Examples of the energy rays include visible light rays, ultraviolet rays, X-rays, and electron beams. In the present embodiment, it is preferred to use ultraviolet rays.

The photopolymerization initiator is not particularly limited, and examples thereof include photopolymerization of a mercaptophosphine oxide photopolymerization initiator, a phenylalkylketone photopolymerization initiator, and an intramolecular dehydrogenation photopolymerization initiator. In the viewpoint of the reactivity and the uniformity of the curing, a mercaptophosphine oxide-based photopolymerization initiator and a phenylalkylketone-based photopolymerization initiator are preferred. Specifically, the mercaptophosphine oxide-based photopolymerization initiator may be exemplified by 2,4,6-trimethylbenzimidylphenylphosphine oxide and 2,2-dimethoxy-1,2-diphenyl. Examples of the phenylalkyl ketone-based photopolymerization initiator include 2-methyl-1-[4-(methylthio)phenyl]-2- Morpholinylpropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinylphenyl)-butanone-1, etc., wherein the free radical generation efficiency is high, deep From the viewpoint of hardenability, 2,4,6-trimethylbenzimidylphenylphosphine oxide is preferred.

The content of the photopolymerization initiator is preferably 0.5 parts by mass or more based on 100 parts by mass of the (meth)acryl-based polymer. When the content of the photopolymerization initiator is 0.5 parts by mass or more based on 100 parts by mass of the (meth)acryl-based polymer, the curing reactivity is improved, and the long-term reliability tends to be improved. The lower limit of the content of the photopolymerization initiator to 100 parts by mass of the (meth)acrylic polymer is preferably 0.7 parts by mass or more, more preferably 1.0 part by mass or more, and if the content of the photopolymerization initiator is too large, The heat resistance tends to decrease, so the upper limit is preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

<Multifunctional monomer>
In the present embodiment, an ethylenically unsaturated compound (polyfunctional monomer) having two or more ethylenically unsaturated groups may be contained in the photocurable adhesive composition. By containing a polyfunctional monomer in the photocurable adhesive composition, heat resistance at high temperature heating can be improved.

Examples of the polyfunctional monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol. (Meth) acrylate, polyethylene glycol di(meth) acrylate, propylene glycol di(meth) acrylate, dipropylene glycol di(meth) acrylate, polypropylene glycol di(meth) acrylate, dibutyl Alcohol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene oxide modified bisphenol A di(meth)acrylate, propylene oxide modified bisphenol A type II ( Methyl) acrylate, cyclohexane dimethanol di(meth) acrylate, ethoxylated cyclohexane dimethanol di(meth) acrylate, dimethylol dicyclopentane di(meth) acrylate Ester, tricyclodecane dimethanol di(meth) acrylate, 1,6-hexanediol di(meth) acrylate, glycerol di(meth) acrylate, pentaerythritol di(meth) acrylate, B Glycol diglycidyl ether di(meth) acrylate, diethylene glycol diglycidyl ether di(meth) acrylate, diglycidyl diglycol di(meth) acrylate, hydroxy a trifunctional monomer such as trimethylacetic acid modified neopentyl glycol di(meth)acrylate or isocyanuric acid ethylene oxide modified diacrylate; trimethylolpropane tri(meth)acrylate, Pentaerythritol tri(meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tris (meth) propylene methoxy ethoxylate Trimethylolpropane, glycerol polyglycidyl ether poly(meth) acrylate, isocyanuric acid ethylene oxide modified tri(meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate Ester, caprolactone modified dipentaerythritol hexa(meth) acrylate, caprolactone modified pentaerythritol tri (meth) acrylate, caprolactone modified pentaerythritol tetra (meth) acrylate, ethylene oxide modification Dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, ethylene oxide modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol IV Trifunctional or higher monomers such as (meth) acrylate and ethoxylated glycerol triacrylate .
Among them, from the viewpoint of heat resistance at the time of high-temperature heating, tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa(methyl) is preferable. )Acrylate.

The content of the polyfunctional monomer is preferably from 5 parts by mass to 30 parts by mass based on 100 parts by mass of the (meth)acrylic polymer. When the content of the polyfunctional monomer is from 5 parts by mass to 30 parts by mass based on 100 parts by mass of the (meth)acrylic polymer, the film forming property at the time of forming the adhesive sheet can be favorably maintained, and the film forming property can be improved. Heat resistance at high temperature. The lower limit of the content of the polyfunctional monomer to 100 parts by mass of the (meth)acrylic polymer is more preferably 7.5 parts by mass or more, further preferably 10 parts by mass or more, and the upper limit is preferably 25 parts by mass or less, more preferably It is 20 parts by mass or less.

<Other ingredients>
In addition to the above-described components, the photocurable adhesive composition of the present embodiment may contain various monomers, decane coupling agents, various fillers such as cerium oxide, aluminum oxide, and hydrated alumina, antioxidants, and light. An additive which is usually added to an adhesive composition such as a stabilizer, an antistatic agent, a leveling agent, an antifoaming agent, a coloring pigment, or an organic solvent.

[Manufacture of photocurable adhesive composition]
The method for producing the photocurable adhesive composition of the present embodiment is not particularly limited, and for example, it can be prepared by mixing and dispersing the above-described components contained in various mixers or dispersers. The mixing and dispersing steps are not particularly limited, and may be carried out by a usual method.

[Stretch Storage Elasticity Coefficient of Photocurable Adhesive Composition]
The viscoelasticity of the photocurable adhesive composition of the present embodiment can be measured by dynamic viscoelasticity measurement (DMA: Dynamic Mechanical Analysis). A film-shaped photocurable adhesive layer having a predetermined thickness was used as a test piece, and a value measured in a tensile measurement measured at a frequency of 1 Hz and a predetermined temperature was obtained using a dynamic viscoelasticity measuring device. (Stretch storage elastic coefficient E'). As the test piece, specifically, a photocurable adhesive layer cut to have a width of 5 mm, a length of 50 mm, and a thickness of 0.1 mm can be used.

Specifically, in the present embodiment, the tensile storage elastic modulus (E') at 25 ° C of the cured product after the energy ray hardening (test piece after curing) is 3.0 × 10 ⁷ Pa to 2.0 × 10 ⁹ Pa, 100. The tensile storage elastic modulus (E') at ° C was 1.0 × 10 ⁷ Pa or less, and the tensile storage elastic modulus (E') at 260 ° C was 1.0 × 10 ⁶ Pa or more. In the present invention, the tensile storage elastic modulus (E') at 25 ° C, 100 ° C, and 260 ° C after curing of the photocurable adhesive composition is in the above range, and is balanced. The ground has adhesion to the adherend and heat resistance in a high temperature region of 100 ° C or higher.

When the tensile storage elastic modulus (E') at 25 ° C of the cured product is 3.0 × 10 ⁷ Pa or more, the cured product can be peeled off without residual glue after heating at a high temperature, and if it is 2.0 × 10 ⁹ Pa or less, it is heated by heating. The laminate is pressed and heated, and the adhesion to the product substrate is improved, and excellent heat resistance can be obtained. With respect to the tensile storage elastic modulus (E') at 25 ° C of the cured product, the lower limit is preferably 4.0 × 10 ⁷ Pa or more, and more preferably 5.0 × 10 ⁷ Pa or more from the viewpoint of easily obtaining the effect of the present invention. Further, the upper limit is preferably 1.0 × 10 ⁹ Pa or less, more preferably 9.0 × 10 ⁸ Pa or less.

When the tensile storage elastic modulus (E') at 100 ° C of the cured product is 1.0 × 10 ⁷ Pa or less, the adhesion to the product substrate is improved by heat pressing and heat lamination, and excellent heat resistance can be obtained. . With respect to the tensile storage elastic modulus (E') at 100 ° C of the cured product, the upper limit is preferably 9.0 × 10 ⁶ Pa or less, and more preferably 8.0 × 10 ⁶ Pa or less from the viewpoint of easily obtaining the effect of the present invention. Further, the lower limit is preferably 1.0 × 10 ⁶ Pa or more, more preferably 1.5 × 10 ⁶ Pa or more, and still more preferably 2.0 × 10 ⁶ Pa or more.

When the tensile storage elastic modulus (E') at 260 ° C of the cured product is 1.0 × 10 ⁶ Pa or more, it can be peeled off without residual glue after heating at a high temperature. With respect to the tensile storage elastic modulus (E') at 260 ° C of the cured product, the lower limit is preferably 1.5 × 10 ⁶ Pa or more, and more preferably 2.0 × 10 ⁶ Pa or more from the viewpoint of easily obtaining the effect of the present invention. Further, the upper limit is preferably 1.0 × 10 ⁷ Pa or less, more preferably 9.0 × 10 ⁶ Pa or less, still more preferably 8.0 × 10 ⁶ Pa or less.

Further, the photocurable adhesive composition of the present embodiment preferably has a tensile storage elastic modulus (E') at 175 ° C of the cured product of 1.0 × 10 ⁶ Pa to 1.0 × 10 ⁷ Pa. When the tensile storage elastic modulus (E') at 175 ° C of the cured product is within the above range, it can be peeled off without residual glue after heating at a high temperature. Regarding the tensile storage elastic modulus (E') at 175 ° C of the cured product, the lower limit is preferably 1.5 × 10 ⁶ Pa or more, more preferably 2.0 × 10 ⁶ Pa or more, and the upper limit is preferably 9.0 × 10 ⁶ Pa. Hereinafter, it is more preferably 8.0 × 10 ⁶ Pa or less.

Further, the photocurable adhesive composition of the present embodiment preferably has a tensile storage elastic modulus (E') at 25 ° C of 1.0 × 10 before the curing of the pre-cured (pre-hardened test piece) before the energy ray irradiation. ⁶ Pa to 9.0 × 10 ⁸ Pa. When the tensile storage elastic modulus (E') at 25 ° C of the dried product before curing is 1.0 × 10 ⁶ Pa or more, the film forming property at the time of forming the pressure-sensitive adhesive sheet can be favorably maintained, and it is 9.0 × 10 ⁸ Pa or less. In addition, when the base material layer has irregularities, the photocurable adhesive layer formed of the photocurable adhesive composition is embedded in the uneven portion (adhesiveness). ) also improved. With respect to the tensile storage elastic modulus (E') at 25 ° C of the dried product before hardening, the lower limit is preferably 1.5 × 10 ⁶ Pa or more, more preferably 2.0 × 10 ⁶ from the viewpoint of easily obtaining the effect of the present invention. In addition to Pa, the upper limit is preferably 8.0 × 10 ⁸ Pa or less, more preferably 7.0 × 10 ⁸ Pa or less.

In order to set the tensile storage elastic modulus (E') before and after curing of the photocurable adhesive composition of the present embodiment to a desired range, the double bond equivalent of the (meth)acrylic polymer is adjusted. A method of weight average molecular weight and glass transition temperature; a method of adjusting the amount of addition of a polyfunctional monomer, and the like.

[Chemical resistance of photocurable adhesive composition]
In addition, the photocurable adhesive composition of the present embodiment is also provided with chemical resistance to a chemical liquid.

In the printed wiring board, a part of the surface of the circuit layer may be plated, and in order to form a plating layer on the portion of the circuit layer, an adhesive sheet for surface protection may be attached to a portion of the surface of the circuit layer where plating is not desired. Cover it. The entire circuit board that shields a part of the circuit layer by the adhesive sheet is brought into contact with (for example, immersed) the acid plating solution or the alkali plating solution, and is subjected to a plating treatment, and the adhesive sheet is peeled off after the plating treatment. A plating film is formed on a part of the upper surface of the circuit layer.

When the chemical resistance of the adhesive sheet is poor, there is a problem that the adhesive layer is corroded when immersed in the chemical solution, the shielding is invalid, and the adhesive layer is adhered to the circuit layer to be subjected to the plating treatment. The photocurable adhesive composition of the form has chemical resistance to a chemical solution such as a plating solution, and thus can be protected when the adhesive sheet is formed and adhered to the adherend and the adherend is brought into contact with the chemical solution. The body is not contaminated.

<adhesive sheet>
The adhesive sheet of this embodiment contains the adhesive layer formed from the photocurable adhesive composition mentioned above. The adhesive layer may be an adhesive layer (photocurable adhesive layer) formed by a photocurable adhesive composition and formed into a dried film, or may be a photocurable adhesive by irradiation with an energy ray. The layer hardened adhesive layer, the adhesive layer is preferably an adhesive layer which is hardened by irradiation with an energy ray.

The adhesive sheet can be coated with a photocurable adhesive composition of the present embodiment by a protective sheet (film) such as polyethylene terephthalate (PET), and dried, and then placed on the opposite side. The protective sheet is obtained, and an adhesive sheet provided with a protective sheet on both sides is obtained. It is particularly preferable to apply a photocurable adhesive composition to a varnish using an organic solvent, apply it to a protective sheet, and dry it. The organic solvent to be used at this time is not particularly limited, and examples thereof include toluene, methyl ethyl ketone, cyclohexanone, propylene glycol monomethyl ether, dimethyl acetamide, isopropyl alcohol, ethyl acetate, and n-propanol. Wait. Among them, from the viewpoint of solubility, methyl ethyl ketone is preferred. Further, the content of the organic solvent in the varnish is preferably from 100 parts by mass to 300 parts by mass, and more preferably from 150 parts by mass to 250 parts by mass, based on the (meth)acrylic polymer.

The protective sheet is not particularly limited, and examples thereof include a group selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyethylene, and polypropylene. In the sheet of one or more kinds of resins, a sheet containing a polyethylene terephthalate resin is preferred from the viewpoint of reducing the production cost.

Regarding the protective sheet, a release treatment may be applied to the surface on which the photocurable resin composition is applied. By performing the mold release treatment on the protective sheet, the protective sheet can be easily peeled off during use, and the workability is improved. The mold release treatment is not particularly limited, and for example, a release agent such as an anthrone-based release agent, a fluorine-based release agent, or a long-chain alkyl graft polymer-based release agent can be used.

As a method of applying the photocurable adhesive composition to the protective sheet, a notch coater, a die coater, a gravure coater, or the like can be suitably used depending on the coating thickness.

The drying of the photocurable adhesive composition can be carried out by a dryer or the like, and the drying conditions at this time can be appropriately adjusted by the type and content of each component.

The thickness of the adhesive layer formed of the photocurable adhesive composition is preferably from 5 μm to 250 μm, more preferably from 5 μm to 125 μm, even more preferably from 5 μm to 75 μm. When the thickness of the dried film of the photocurable adhesive composition is within the above range, the followability and adhesion to the adherend (for example, a circuit layer or a protective member) are improved, and peeling can be performed without residue at the time of peeling. .
Further, in the case where the adhesive sheet is provided with a protective sheet in addition to the adhesive layer, it is also preferred that the thickness of the adhesive sheet after drying is 5 μm to 250 μm, more preferably 5 μm to 125 μm, and even more preferably 5 μm. 75 μm. When the thickness of the adhesive sheet is in the above range, the adhesive sheet is excellent in handleability, and the adherence, adhesion, and peeling property to the adherend are also improved, and the protective effect of the adherend can be exhibited.

The adhesive sheet can be hardened by illuminating the energy ray. The energy line is not particularly limited, and an active energy ray such as visible light, ultraviolet light, X-ray or electron beam can be used, and from the viewpoint of efficiently performing the curing reaction, ultraviolet rays are preferably used.
As a light source of ultraviolet rays, a light source that emits ultraviolet rays (UV) can be used. Examples of the light source of the ultraviolet light include a metal halide lamp, a high pressure mercury lamp, a xenon lamp, a mercury xenon lamp, a halogen lamp, a pulse xenon lamp, and a light emitting diode (LED).

[Electronic material components]
The adhesive sheet containing the photocurable adhesive composition of this embodiment can be used as a surface protection sheet of an electronic material member. Examples of the electronic material member include various substrates that can be used in electronic material members such as a printed wiring board, an integrated circuit (IC) wafer, a semiconductor device, a package substrate, and a lead frame.
[Examples]

Hereinafter, the present invention will be specifically described by way of examples and comparative examples, but the invention is not limited to the examples.

The respective components and materials used in the examples and comparative examples are as follows.
[Ultraviolet hardening prepolymer]
(1) to (12): acrylated acrylate (A) to acrylated acrylate (L)
The acrylated acrylate (A) to the acrylated acrylate (L) having the composition described in Table 1 was prepared as the (meth) according to Synthesis Example 1 to Synthesis Example 7 and Comparative Synthesis Example 1 to Comparative Synthesis Example 5 below. Acrylic polymer. In addition, "BA" is abbreviated as butyl acrylate, "MMA" is abbreviated as methyl methacrylate, "AA" is abbreviated as acrylic acid, and "GMA" is abbreviated as glycidyl methacrylate. "EA" is an abbreviation for ethyl acrylate, and "AN" is an abbreviation for acrylonitrile.

[Table 1]

(13) Polyurethane (meth) acrylate (M)
Polyurethane (meth) acrylate (M) was prepared according to the following Comparative Synthesis Example 6 (weight average molecular weight was 50,000, double bond equivalent was 2,000 g/eq, glass transition temperature (Tg) was 5 ° C, The acid value is 1 mgKOH/g).

[Polyfunctional monomer]
(1) Polyfunctional monomer (a)
Dipentaerythritol hexaacrylate (manufactured by Daicel-Allnex Co., Ltd., product name: DPHA, hexafunctional, weight average molecular weight 524, acid value 0.1 mgKOH/g)
(2) Polyfunctional monomer (b)
Trimethylolpropane triacrylate (manufactured by Daicel O'Neills Co., Ltd., product name: TMPTA, trifunctional, weight average molecular weight 286, acid value 0.1 mgKOH/g)
(3) Polyfunctional monomer (c)
Tricyclodecane dimethanol diacrylate (manufactured by Daicel O'Nexus Co., Ltd., product name: IRR214-K, difunctional, weight average molecular weight 300, acid value 0.1 mgKOH/g)

[Photopolymerization initiator]
(1) Photopolymerization initiator (a)
2,4,6-trimethylbenzimidylphenylphosphine oxide (manufactured by BASF Corporation, trade name "Irgacure TPO", sulfhydryl phosphine oxide photopolymerization initiator)

(Synthesis Example 1) Acrylate acrylate (A)
100.0 g of propylene glycol monomethyl ether (PGM) as a polymerization solvent was added to a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a nitrogen introduction tube, and the temperature was raised while stirring under a nitrogen stream. 80 ° C. 40 g of butyl acrylate, 49.5 g of methyl methacrylate, 3.5 g of acrylic acid, and 3.5 g of acrylic acid pre-mixed at room temperature were added dropwise from a dropping funnel over a period of 3 hours at a temperature of 80 ° C. A mixture of 0.5 g of azobisisobutyronitrile as a starting agent. After the completion of the dropwise addition, the reaction solution was heated to 90 ° C while stirring, and the temperature of the reaction solution was maintained at 90 ° C while stirring for 2 hours to obtain a copolymer.
93 g of the solid content of the copolymer obtained above, 7 parts by mass of glycidyl methacrylate, 0.8 parts by mass of triethylamine as a catalyst, and 0.05 parts by mass of hydroquinone as a polymerization inhibitor. Into the reaction vessel, the reaction was carried out at 100 ° C for 18 hours, and an acrylated acrylate (A) was obtained by an addition reaction.
In addition, the addition reaction is completed when the acid value measured according to JIS K 5601 is 1 mgKOH/g or less. The obtained acrylated acrylate (A) had a weight average molecular weight of 200,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 15 °C.

(Synthesis Example 2) Acrylate acrylate (B)
The content of butyl acrylate was 42 g, the content of methyl methacrylate was 53.5 g, the content of acrylic acid was 1.5 g, and the content of glycidyl methacrylate was 3 parts by mass. Except for this, an acrylated acrylate (B) was obtained by the same method as in Synthesis Example 1.
The obtained acrylated acrylate (B) had a weight average molecular weight of 200,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 5,000 g/eq, and a Tg of 15 °C.

(Synthesis Example 3) Acrylate acrylate (C)
The content of butyl acrylate was 39 g, the content of methyl methacrylate was 40 g, the content of acrylic acid was 7 g, and the content of glycidyl methacrylate was 14 parts by mass. Except for this, an acrylated acrylate (C) was obtained by the same method as in Synthesis Example 1.
The obtained acrylated acrylate (C) had a weight average molecular weight of 200,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 1,000 g/eq, and a Tg of 15 °C.

(Synthesis Example 4) Acrylate acrylate (D)
The content of butyl acrylate was 26.5 g, the content of methyl methacrylate was 63 g, the content of acrylic acid was 3.5 g, and the content of glycidyl methacrylate was 7 parts by mass. Except for this, an acrylated acrylate (D) was obtained by the same method as in Synthesis Example 1.
The obtained acrylated acrylate (D) had a weight average molecular weight of 200,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 40 °C.

(Synthesis Example 5) Acrylate acrylate (E)
In the synthesis example 1, the composition of the mixed liquid added to the reaction container was 64.0 g of ethyl acrylate, 21 g of acrylonitrile, 8 g of acrylic acid, and 0.5 g of azobisisobutyronitrile, by Acrylate acrylate (E) was obtained in the same manner as in Synthesis Example 1.
The obtained acrylated acrylate (E) had a weight average molecular weight of 400,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 10 °C.

(Synthesis Example 6) Acrylate acrylate (F)
In Synthesis Example 1, the composition of the mixed liquid added to the reaction vessel was 44 g of butyl acrylate, 20 g of ethyl acrylate, 21 g of acrylonitrile, 8 g of acrylic acid, and 0.5 g of azobisisobutyronitrile. Except for this, an acrylated acrylate (F) was obtained by the same method as in Synthesis Example 1.
The obtained acrylated acrylate (F) had a weight average molecular weight of 400,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 10 °C.

(Synthesis Example 7) Acrylate acrylate (G)
In Synthesis Example 1, the composition of the mixed solution added to the reaction vessel was 44 g of butyl acrylate, 20 g of ethyl acrylate, 10 g of methyl methacrylate, 14 g of acrylonitrile, 8 g of acrylic acid, and even. An acrylated acrylate (G) was obtained by the same method as in Synthesis Example 1, except that 0.5 g of nitrogen bisisobutyronitrile was used.
The obtained acrylated acrylate (G) had a weight average molecular weight of 400,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 10 °C.

(Comparative Synthesis Example 1) Acrylate Acrylate (H)
The content of butyl acrylate was 37 g, the content of methyl methacrylate was 33 g, the content of acrylic acid was 10 g, and the content of glycidyl methacrylate was 20 parts by mass. Except for this, an acrylated acrylate (H) was obtained by the same method as in Synthesis Example 1.
The obtained acrylated acrylate (H) had a weight average molecular weight of 200,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 750 g/eq, and a Tg of 15 °C.

(Comparative Synthesis Example 2) Acrylate Acrylate (I)
The content of butyl acrylate was 42 g, the content of methyl methacrylate was 55.9 g, the content of acrylic acid was 0.7 g, and the content of glycidyl methacrylate was 1.4 parts by mass. Otherwise, the acrylated acrylate (I) was obtained by the same method as in Synthesis Example 1.
The obtained acrylated acrylate (I) had a weight average molecular weight of 200,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 10,000 g/eq, and a Tg of 15 °C.

(Comparative Synthesis Example 3) Acrylate Acrylate (J)
The content of butyl acrylate was set to 16 g, the content of methyl methacrylate was set to 73.5 g, the content of acrylic acid was set to 3.5 g, and the content of glycidyl methacrylate was set to 7 parts by mass. Further, an acrylated acrylate (J) was obtained by the same method as in Synthesis Example 1.
The obtained acrylated acrylate (J) had a weight average molecular weight of 200,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 60 °C.

(Comparative Synthesis Example 4) Acrylate Acrylate (K)
The mixture was added dropwise from the dropping funnel at a temperature of 80 ° C for 6 hours, and after the completion of the dropwise addition, the temperature was raised to 90 ° C while stirring the reaction solution, and the temperature of the reaction solution was maintained at 90 ° C while stirring. An acrylated acrylate (K) was obtained by the same method as in Synthesis Example 1, except that a copolymer was obtained in an hour.
The obtained acrylated acrylate (K) had a weight average molecular weight of 800,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 15 °C.

(Comparative Synthesis Example 5) Acrylate Acrylate (L)
The mixture was added dropwise from the dropping funnel at a temperature of 80 ° C for 1 hour, and after the completion of the dropwise addition, the temperature was raised to 90 ° C while stirring the reaction solution, and the temperature of the reaction solution was maintained at 90 ° C while stirring. The acrylated acrylate (L) was obtained by the same method as in Synthesis Example 1, except that the copolymer was obtained in an hour.
The obtained acrylated acrylate (L) had a weight average molecular weight of 10,000, a solid content concentration of 40.5 mass%, a double bond equivalent of 2,000 g/eq, and a Tg of 15 °C.

(Comparative Synthesis Example 6) Polyurethane (meth) acrylate (M)
In a four-necked flask equipped with a thermometer, a cooling tube, and a stirring device, hexamethylene diisocyanate (manufactured by Tosoh Co., Ltd., product name: HDI, abbreviated as HDI) was 33.3 g, and the weight average molecular weight was 400. 59.4 g of polycarbonate diol, 7.3 g of dimethylolbutyric acid, 1 g of an organic tin compound such as dibutyltin laurate as a catalyst, and 100 g of methyl ethyl ketone as an organic solvent were placed in a reaction vessel. The reaction was carried out at 70 ° C for 24 hours.
In order to confirm the reaction state of the obtained composition, an infrared (IR) measuring machine was used for the analysis. It was confirmed in the IR chart that the NCO characteristic absorption (2270 cm ^-1 ) of the composition disappeared, and it was confirmed that the composition was a urethane acrylate having a carboxyl group.
Next, 100 parts by mass of the obtained urethane acrylate having a carboxyl group, 7.1 parts by mass of glycidyl methacrylate, 0.7 parts by mass of triethylamine as a catalyst, and p-phenylene as a polymerization inhibitor. 0.05 part by mass of the phenol was placed in a reaction vessel, and the reaction was carried out at 75 ° C for 12 hours, and a polyurethane (meth) acrylate (M) was obtained by an addition reaction.
Further, the addition reaction was terminated when the acid value became 1 mgKOH/g. The obtained polyurethane (meth) acrylate (M) had a weight average molecular weight of 50,000, a solid content concentration of 50% by mass, a double bond equivalent of 2,000 g/eq, and a Tg of 5 °C.

<Example 1>
1. Preparation of Photocurable Adhesive Composition 100 parts by mass of acrylated acrylate (A) was added to a reaction vessel, and further 1.5 parts by mass of a photopolymerization initiator (a) and methyl ethyl ketone 180 as a solvent were added. The mass fraction was uniformly stirred to obtain a photocurable adhesive composition.

2. Evaluation of dried product before hardening (2-1) Preparation of an adhesive sheet before curing Using a protective film of polyethylene terephthalate having a release thickness of 50 μm as a substrate layer, The photocurable adhesive composition obtained was applied onto the protective film so as to have a thickness of 20 μm after drying. After drying at 130 ° C for 5 minutes, the same protective film was provided on the upper surface of the photocurable adhesive layer to obtain a pre-hardened adhesive sheet having a polyethylene terephthalate film (protective film) on both sides.

(2-2) Evaluation of the followability of the base material layer The single-sided protective film of the pre-cured pressure-sensitive adhesive sheet obtained in the above (2-1) was peeled off to evaluate the followability of the photocurable adhesive layer to the substrate layer. . As the base material layer, a copper-clad substrate having a thickness of 200 μm which was subjected to an ultra-thinning series adhesion improving treatment (hereinafter referred to as CZ roughening treatment) on the surface of the copper foil was bonded by vacuum lamination. The vacuum lamination is carried out at a temperature of 25 ° C to 50 ° C, a pressure of 0.1 MPa to 0.5 MPa, a vacuum for 5 seconds to 30 seconds, and a pressurization for 30 seconds. The embedding property of the photocurable adhesive layer at this time was evaluated according to the following evaluation criteria. The results are shown in Table 2.
[evaluation benchmark]
○: The unevenness of the surface of the copper foil as the base material layer can be followed by the photocurable adhesive layer without voids.
X: In the unevenness in the surface of the copper foil as the base material layer, the photocurable adhesive layer has a state in which voids remain, which is defective.

(2-3) Evaluation of film forming property of the adhesive sheet before hardening After tearing both ends of the adhesive sheet before hardening, the length of 100 m was loosely wound around the acrylonitrile-butadiene having a diameter f of 6 吋. A styrene (Acrylonitrile Butadiene Styrene, ABS) tube was obtained, and a sample for measurement in a roll shape was obtained. In the state in which the axis of the ABS tube was horizontal with respect to the ground, the sample for measurement was placed in a room temperature environment at a temperature of 23 ° C and a humidity of 50% for 7 days, and the winding state of the roll was evaluated based on the following evaluation criteria to confirm the photohardening. Film forming properties of the adhesive layer. The results are shown in Table 2.
[evaluation benchmark]
○: The adhesive sheet was wound in a state of no wrinkles, and the resin composition did not ooze out from the end portion of the roll, so that it was good.
X: Wrinkles were observed in the roll-shaped adhesive sheet, and wrinkles remained when the film was pulled out, and the resin composition was oozing out from the end portion of the roll, which was difficult to pull out, and there was a problem in practical use.

(2-4) Measurement of Tensile Storage Elasticity (E') The adhesive sheet was cut into a size of 5 mm in length and 50 mm in length before peeling, and the protective film on both sides was peeled off to obtain a sample for measurement.
The tensile storage elastic modulus E' was measured using a dynamic viscoelasticity measuring apparatus (RSA-G2 manufactured by TA Instruments). The measurement conditions were carried out at a temperature increase rate of 10.0 ° C/min in a temperature range of -50 ° C to 300 ° C, and the frequency was set to 1 Hz. The tensile storage elastic modulus E' at 25 ° C, 100 ° C, 175 ° C and 260 ° C is shown in Table 2. In addition, "not" in the table means that the photocurable adhesive layer is stretched and cannot be measured.

3. Evaluation of the cured product (3-1) Preparation of the sample for measurement (cured material) The single-sided protective film of the pre-cured adhesive sheet obtained in the "(2-1) Preparation of the adhesive sheet before curing" is peeled off. The photocurable adhesive layer was adhered to a copper-clad substrate having a thickness of 200 μm which was subjected to CZ roughening treatment on the surface of the copper foil by vacuum lamination. The vacuum lamination is carried out at a temperature of 25 ° C to 50 ° C, a pressure of 0.1 MPa to 0.5 MPa, a vacuum for 5 seconds to 30 seconds, and a pressurization for 30 seconds. Then, UV exposure was performed from the other single-sided protective film. The UV exposure was carried out in an ultrahigh pressure mercury lamp light source and the cumulative light amount at λ = 365 nm was 3,000 mJ/cm ² .
The photocurable resin adhesive layer and the surface layer after the UV curing are aligned to a product circuit board as a solder resist, and bonded by a vacuum laminator. The vacuum lamination is carried out at a temperature of 100 ° C to 160 ° C, a pressure of 0.1 MPa to 1.0 MPa, a vacuum for 5 seconds to 30 seconds, and a pressurization period of 60 seconds to 600 seconds to obtain a sample for measurement.

(3-2) Evaluation of heat resistance 1 (resistance to solder reflow)
The sample for measurement was placed in a solder reflow device and allowed to stand in an environment of 260 ° C for 20 seconds to evaluate heat resistance. The evaluation was carried out in accordance with the following evaluation criteria. The results are shown in Table 2.
[evaluation benchmark]
○: It was good without swelling or peeling.
×: Defective expansion or peeling occurred.

(3-3) Evaluation of heat resistance 2 (resistance to sealant molding)
The sample for measurement was placed in a hot air circulation type heating oven, and allowed to stand in an environment of 175 ° C for 6 hours to evaluate heat resistance. The evaluation was carried out in accordance with the following evaluation criteria. The results are shown in Table 2.
[evaluation benchmark]
○: It was good without swelling or peeling.
×: Defective expansion or peeling occurred.

(3-4) Evaluation of the peelability After the evaluation of the heat resistance of the above (3-2) and (3-3) using the sample for measurement prepared in the above (3-1), the product of the product circuit board was evaluated. The solder resist surface and the photocurable resin adhesive layer of the adhesive sheet were peeled off, and evaluated according to the following evaluation criteria. The results are shown in Table 2.
[evaluation benchmark]
○: It can be easily peeled off, and the residual flux of the adhesive layer is not present on the solder resist of the product, so it is good.
X: It is difficult to peel off, and the residual glue of the adhesive layer exists on the product solder resist, so it is defective.

(3-5) Measurement of Tensile Storage Elasticity Coefficient (E') For the pre-hardened adhesive sheet obtained in the "(2-1) Preparation of Adhesive Sheet before Hardening", an ultra-high pressure mercury lamp light source was used, λ = 365 The photocurable adhesive layer is cured by UV exposure so that the integrated light amount at nm becomes 3,000 mJ/cm ² . Thereafter, the protective films on both sides were peeled off, and a sample for measurement having a size of 5 mm in width and 50 mm in length was obtained.
The tensile storage elastic modulus E' was measured using a dynamic viscoelasticity measuring apparatus (RSA-G2 manufactured by TA Instruments Co., Ltd.). The measurement conditions were carried out at a temperature increase rate of 10.0 ° C/min in a temperature range of -50 ° C to 300 ° C, and the frequency was set to 1 Hz. The tensile storage elastic modulus E' at 25 ° C, 100 ° C, 175 ° C and 260 ° C is shown in Table 2.

<Example 2>
A photocurable adhesive composition of Example 2 was produced in the same manner as in Example 1 except that the acrylated acrylate (B) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 2.

<Example 3>
A photocurable adhesive composition of Example 3 was produced in the same manner as in Example 1 except that the acrylated acrylate (C) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 2.

<Example 4>
A photocurable adhesive composition of Example 4 was produced in the same manner as in Example 1 except that 10 parts by mass of the polyfunctional monomer (a) was further added to the first embodiment to prepare a photocurable adhesive composition. The evaluation was carried out in the same manner as in Example 1. The results are shown in Table 2.

<Example 5>
A photocurable adhesive composition of Example 5 was produced in the same manner as in Example 1 except that 10 parts by mass of the polyfunctional monomer (b) was further added to the first embodiment to prepare a photocurable adhesive composition. The evaluation was carried out in the same manner as in Example 1. The results are shown in Table 2.

<Example 6>
A photocurable adhesive composition of Example 6 was produced in the same manner as in Example 1 except that 10 parts by mass of the polyfunctional monomer (c) was further added to the Example 1 to prepare a photocurable adhesive composition. The evaluation was carried out in the same manner as in Example 1. The results are shown in Table 2.

<Example 7>
A photocurable adhesive composition of Example 7 was produced in the same manner as in Example 1 except that the acrylated acrylate (D) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 2.

<Example 8>
A photocurable adhesive composition of Example 7 was produced in the same manner as in Example 1 except that the acrylated acrylate (E) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 2.

<Example 9>
A photocurable adhesive composition of Example 7 was produced in the same manner as in Example 1 except that the acrylated acrylate (F) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 2.

<Example 10>
A photocurable adhesive composition of Example 7 was produced in the same manner as in Example 1 except that the acrylated acrylate (G) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 2.

<Comparative Example 1>
A photocurable adhesive composition of Comparative Example 1 was produced in the same manner as in Example 1 except that the acrylated acrylate (H) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 3.

<Comparative Example 2>
A photocurable adhesive composition of Comparative Example 2 was produced in the same manner as in Example 1 except that the acrylated acrylate (I) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 3.

<Comparative Example 3>
A photocurable adhesive composition of Comparative Example 3 was produced in the same manner as in Example 1 except that the acrylated acrylate (J) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 3.

<Comparative Example 4>
A photocurable adhesive composition of Comparative Example 4 was produced in the same manner as in Example 1 except that the acrylated acrylate (K) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 3.

<Comparative Example 5>
A photocurable adhesive composition of Comparative Example 5 was produced in the same manner as in Example 1 except that the acrylated acrylate (L) was used instead of the acrylated acrylate (A), and the same procedure as in Example 1 was carried out. Conduct an evaluation. The results are shown in Table 3.

<Comparative Example 6>
A photocurable adhesive composition of Comparative Example 6 was produced in the same manner as in Example 1 except that the acryl acrylate (M) was used instead of the acrylated acrylate (A). The evaluation was carried out in the same manner as in Example 1. The results are shown in Table 3.

[Table 2]

[table 3]

As is clear from the results of Tables 2 and 3, in Examples 1 to 10, the adhesive properties of the adhesive layer before and after curing were excellent, and the embedding property and film forming property of the base material layer, and after hardening and The product substrate has good adhesion, heat resistance, chemical resistance, and peelability.
On the other hand, in the adhesive layer after curing in Comparative Example 1, the tensile storage elastic modulus (E') at 100 ° C was 2.8 × 10 ⁷ Pa, and the adhesion of the adhesive layer of such a value to the product substrate was observed. Poor heat resistance. The tensile storage elastic modulus (E') at 260 ° C of the adhesive layer after curing in Comparative Example 2 was 5.0 × 10 ⁵ Pa, and the heat resistance and peelability of the adhesive layer showing such a value were inferior. The tensile storage elastic modulus (E') at 25 ° C of the adhesive layer after curing in Comparative Example 3 was 2.6 × 10 ⁹ Pa, and the adhesive layer exhibiting such a value was inferior in adhesion to the product substrate and heat resistance. Further, the tensile storage elastic modulus (E') at 25 ° C of the adhesive layer before curing was 1.1 × 10 ⁹ Pa, and the adhesiveness of the adhesive layer having such a value was inferior to the substrate layer. The tensile storage elastic modulus (E') at 25 ° C of the adhesive layer after curing in Comparative Example 4 was 2.3 × 10 ⁹ Pa, and the adhesive layer exhibiting such a value was inferior in adhesion to the product substrate and heat resistance. Further, the tensile storage elastic modulus (E') at 25 ° C of the adhesive layer before curing was 1.2 × 10 ⁹ Pa, and the adhesiveness of the adhesive layer having such a value was inferior to the substrate layer. The tensile storage elastic modulus (E') at 25 ° C of the adhesive layer after curing in Comparative Example 5 was 1.5 × 10 ⁶ Pa, and the heat resistance and peeling property of the adhesive layer showing such a value were inferior. Further, the tensile storage elastic modulus (E') at 25 ° C of the adhesive layer before curing was 8.0 × 10 ⁵ Pa, and the adhesiveness of the adhesive layer showing such a value was inferior. In the adhesive layer of Comparative Example 6, a polyurethane (meth) acrylate was used, and the adhesive layer using such a composition was inferior in heat resistance.

The present invention has been described in detail with reference to the preferred embodiments thereof. The present application is based on Japanese Patent Application No. 2018-003527, filed on Jan.
[Industrial availability]

The adhesive sheet containing the photocurable adhesive composition of the present invention is used for plating protection when manufacturing a printed wiring board, or for mounting an integrated circuit (IC) wafer or for bonding with a base substrate during resin molding. The adhesive used is industrially usable.

no

no

Claims (12)

A photocurable adhesive composition capable of being cured by irradiation with an energy ray, the photocurable adhesive composition comprising a (meth)acrylic polymer and a photopolymerization initiator, which are irradiated by an energy ray After the hardening of the photocurable adhesive layer formed of the photocurable adhesive composition, the tensile storage elastic modulus (E') at 25 ° C is 3.0 × 10 ⁷ Pa to 2.0 × 10 ⁹ The tensile storage elastic modulus (E') at Pa, 100 ° C was 1.0 × 10 ⁷ Pa or less, and the tensile storage elastic modulus (E') at 260 ° C was 1.0 × 10 ⁶ Pa or more. The photocurable adhesive composition according to claim 1, wherein the photocurable adhesive layer has a tensile storage elastic modulus (E') at 25 ° C before curing by energy ray irradiation. It is 1.0 × 10 ⁶ Pa to 9.0 × 10 ⁸ Pa. The photocurable adhesive composition according to claim 1 or 2, wherein the (meth)acrylic polymer has a glass transition temperature of from 0 ° C to 50 ° C. The photocurable adhesive composition according to claim 1 or 2, wherein the (meth)acrylic polymer has a weight average molecular weight of 50,000 to 500,000. The photocurable adhesive composition according to claim 1 or 2, wherein the (meth)acrylic polymer has a double bond equivalent of from 1,000 g/eq to 5,000 g/eq. A photocurable adhesive layer formed of the photocurable adhesive composition according to any one of claims 1 to 5. An adhesive sheet having the photocurable adhesive layer as described in claim 6 of the patent application. An adhesive layer which is cured by an energy ray to form a photocurable adhesive layer formed of the photocurable adhesive composition according to any one of claims 1 to 5 And got it. An adhesive sheet having an adhesive layer as described in claim 8 of the patent application. The adhesive sheet according to claim 9, which has a peeling property. The adhesive sheet according to claim 9 or 10, which is used as a surface protection sheet for an electronic material member. An electronic material member in which an adhesive sheet as described in claim 11 of the patent application is attached.