JP2011148864A - Adhesive composition and adhesive sheet using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition satisfying both of high heat resistance and easy adhesiveness to an adherend. <P>SOLUTION: The adhesive composition contains (A) an acrylic adhesive compound having a mass average molecular weight of ≥300,000, and an acid value of ≥1 and <5 mg-KOH/g, (B) an acrylic adhesive compound having a mass average molecular weight of ≥3,000 and ≤(the mass average molecular weight of the combined component (A)+200,000), and an acid value of ≥30 and ≤200 mg-KOH/g, and (C) a specific crosslinking agent, wherein, the ratio of the formulated compounds (A) to (B), the modulus and the adhesive power within a temperature range of 23-260°C, the ratio (X)/(Y) of the modulus (X) at 23°C to the modulus (Y) at 260°C are present in specific ranges. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention is required to have heat resistance such as, for example, a mask material for solder process, a chip, various capacitors, a battery, a printed circuit board and the like during transportation, a backup, a plating mask, and a mask during baking coating for various vehicles. A pressure-sensitive adhesive composition that can be used in the process and a pressure-sensitive adhesive sheet using the same, and can suppress foaming even in a temperature profile of a solder used when mounting an electronic component on a printed circuit board, and has excellent adhesion and aggregation The present invention relates to a pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet.

Conventionally, a reinforcing plate (stiffener) is laminated on the surface of the flexible printed circuit board on which the electronic components such as chips and capacitors are mounted, and the surface of the power supply and other connectors on the opposite side of the circuit. This prevents high-precision mounting and bending of the connector. The adhesive used when laminating the reinforcing plate is a soldering environment for electronic components. For example, in the case of lead-free solder, the solder melting temperature is about 220 ° C., and the solder reflow process is performed at a temperature environment of about 260 ° C. Therefore, generally, an epoxy resin adhesive having high heat resistance, a polyimide adhesive, or a silicone adhesive is used.

Since these adhesives are usually liquid, a coating operation must be performed prior to application such as screen printing or spin coating, and workability and liquid management are complicated and a layer having a uniform thickness and surface is required. There was a drawback that it was difficult to form.

On the other hand, in order to improve the handling property of the adhesive, a sheet-like adhesive, for example, an adhesive sheet mainly composed of an epoxy resin and B-staged, a hot-melt adhesive, a urethane resin, or a polyester resin Adhesives such as vinyl chloride-vinyl acetate copolymer are known. However, these adhesives generally have low adhesion to the adherend at room temperature, so that the adhesive is cured until the adherend is adhered. It has to be fixed with a tool or the like, and the workability is low, and it is necessary to prepare a jig or a heating device, which is not always satisfactory in terms of energy consumption reduction and cost.

In order to improve the disadvantages of such adhesives and adhesive sheets, for example, usually a rubber-based elastomer or acrylic resin is used as the main polymer, and a tackifying resin or a crosslinking agent is blended into this to form a tape or sheet. In order to impart heat resistance to these, and when using rubber-based elastomers, add heat-reactive phenolic resin to rubber-based elastomers made of natural rubber or synthetic rubber to control the crosslinking density. A pressure-sensitive adhesive sheet made of a resin vulcanization type imparted with heat resistance has been proposed.

However, these pressure-sensitive adhesive tapes must maintain a uniform temperature environment (usually 150 to 180 ° C.) in order to dry and crosslink, and quality variations, substrates and pressure-sensitive adhesives are related to this temperature maintenance. There are disadvantages such as degradation of the rubber component of the device itself and reduction in productivity because the line must be moved at a very low speed.

Also, when using an acrylic resin-based pressure-sensitive adhesive, if the purpose is to increase the molecular weight of the polymer in the pressure-sensitive adhesive, a photopolymerizable pressure-sensitive adhesive is used, so that unreacted monomers remain during photopolymerization, The remaining monomer causes the odor at the time of use, or acts as a plasticizer in the pressure-sensitive adhesive, resulting in a significant decrease in cohesive strength at high temperatures.

Furthermore, for the purpose of improving cohesion for improving heat resistance, a pressure-sensitive adhesive sheet in which the polymer constituting the pressure-sensitive adhesive is made high in molecular weight has been proposed. In the case of an agent, it has not yet been satisfactory in the field where heat resistance over a specific temperature is required, for example, resistance to a temperature profile when an electronic component is fixed on a printed circuit board with lead-free solder.

For these problems, as an adhesive composition or an adhesive sheet, for example, an acrylic polymer having a weight average molecular weight of 1 million or more having a shear elastic modulus at 200 ° C. of 0.3 × 10 6 to 3.0 × 10 6 dyn / cm 2 ( A pressure-sensitive adhesive composition containing A) has been proposed (see Patent Document 1), which has a low elastic modulus of 0.3 × 10 5 to 3.0 × 10 5 Pa at 200 ° C. When the polyimide surface or polyimide film of a copper-clad laminate with high hygroscopicity (hereinafter also referred to as CCL) is used as an adherend, the adhesive softens at a high temperature such as during the solder reflow process, There are drawbacks that the pressure-sensitive adhesive is foamed, and that the adhesive is lifted or peeled off.

Further, the pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive composition containing an acrylic polymer as a main component and containing a chain transfer material, and has an initial gel fraction of 40 to 70% by weight, and a specific heat treatment A pressure-sensitive adhesive sheet (see Patent Document 2) in which the difference between the gel fraction (% by weight) after the solder reflow process performed under conditions and the initial gel fraction (% by weight) is 10 or less has been proposed. In this case, although the adhesive property to be applied to the part where the repulsive force is taken into consideration, the pressure-sensitive adhesive composition to be used contains a lot of low molecular weight components. In addition, if the CCL polyimide surface or polyimide film with high hygroscopicity is used as the adherend, the adhesive foams at high temperatures such as during the solder reflow process, Peeling On the record occurs, when used in high temperature, smell derived from the low molecular weight component contained in the pressure-sensitive adhesive composition is likely to adversely affect the working environment.

In addition, at least one acrylic monomer and imide group-containing monomer as components on one or both sides of a polyimide-based substrate subjected to a good adhesion treatment by sputter etching treatment to a single-layer film or sheet made of a polyimide-based polymer, An imide-based pressure-sensitive adhesive member (see Patent Document 3) provided with a pressure-sensitive adhesive layer based on an acrylic copolymer having a soluble fraction of less than 50% in ethyl acetate at 20 ° C. has been proposed. Since the acrylic adhesive layer is composed of an acrylic monomer and an imide group-containing monomer, when using a highly hygroscopic CCL polyimide surface or polyimide film as an adherend, for example, soldering Disadvantage that the adhesive is softened in the reflow process, the adhesive foams, or the peeling force is lowered, causing floating or peeling from the adherend A.

Further, as the heat-resistant adhesive composition, 97.5 to 99% by mass of an alkyl (meth) acrylate having 3 to 12 carbon atoms in the alkyl group portion as a main component monomer and a functional group-containing acrylic monomer 2.5 to 1 85 to 15% by mass of an acrylic high molecular weight copolymer having a mass average molecular weight of 600,000 or more and an acid value of 20 mgKOH / g or less, Acrylic low molecular weight copolymer having a mass average molecular weight of 500,000 or less and an acid value of 25 mgKOH / g or more, comprising 90 to 98% by mass of 12 alkyl (meth) acrylates and 10 to 2% by mass of a functional group-containing acrylic monomer 100 parts by weight of a copolymer composition containing 15 to 85% by weight of the polymer as a main component and 1 to 15 parts by weight of a crosslinking agent, and the main component of the acrylic high molecular weight copolymer Proposed a heat-resistant pressure-sensitive adhesive composition in which the difference between the carbon number of the alkyl group portion of the mer and the carbon number of the alkyl group portion of the main component monomer of the acrylic low molecular weight copolymer is 2 or less (see Patent Document 4) Has been. However, since this uses a pressure-sensitive adhesive having 2-ethylhexyl acrylate as a constituent component in particular, foaming occurs in the pressure-sensitive adhesive when used in an environment exceeding 200 ° C. at high temperatures. There is a problem above.

JP 2004-196867 A (Claims and others) JP 2007-302868 A (Claims and others) JP-A-10-296901 (Claims and others) JP 2008-38103 A (Claims and others)

The present invention overcomes the drawbacks of the conventional adhesive or pressure-sensitive adhesive sheet described above, and when used in a high heat resistance, particularly a solder temperature profile, the pressure-sensitive adhesive foams at each temperature range, or adheres to the adherend. The present invention was made to provide a pressure-sensitive adhesive composition that satisfies both the heat resistance that there is no occurrence of floating or peeling in between and the easy attachment to an adherend, and a pressure-sensitive adhesive sheet using the same. .

For the acrylic pressure-sensitive adhesive having a specific composition, by using a pressure-sensitive adhesive composition in which the elastic modulus in a specific temperature range and the adhesive force with the adherend are adjusted to a specific range, It was found that heat resistance and adhesion to the adherend can be satisfied at the same time, and the present invention has been made based on this finding.

That is, this invention provides the following adhesive compositions and an adhesive sheet using the same.
[1] (A) Acrylic adhesive compound having a mass average molecular weight of 300,000 or more, an acid value of 1 mgKOH / g or more and less than 5 mgKOH / g, (B) a component having a mass average molecular weight of 3000 or more Selected from the group consisting of an acrylic adhesive compound having a weight average molecular weight of +200,000 or less, an acid value of 30 mgKOH / g or more and 200 mgKOH / g or less, and (C) an epoxy crosslinking agent, an isocyanate crosslinking agent and an amino crosslinking agent It is composed of at least one crosslinking agent, and the blending ratio of the component (A) to the component (B) is in the range of 55:45 to 95: 5, and the elastic modulus is 0.1 over the entire temperature range of 23 to 260 ° C. The range (X) / (Y) of the elastic modulus (X) at 23 ° C. and the elastic modulus (Y) at 260 ° C. is in the range of 0.5-10. Inside Adhesive composition, characterized in that there.
[2] The (A) component is a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms and a monomer having a reactive functional group for the (C) component. The (B) component is a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 9 carbon atoms and a monomer having a reactive functional group for the component (C), and ( The pressure-sensitive adhesive composition according to [1], wherein both the component A) and the component (B) have a glass transition temperature in the range of -70 ° C to 50 ° C.
[3] The ratio of the functional group in the component (C) is 0.5 to 6 times in terms of the equivalent ratio with respect to the total amount of the reactive functional group in the adhesive compound of the component (A) and the component (B). The pressure-sensitive adhesive composition according to [1] or [2], which is an amount.
[4] The pressure-sensitive adhesive composition according to any one of [1] to [3], wherein the component (C) is a carbon six-membered ring compound having at least one diglycidylamino group.
[5] The pressure-sensitive adhesive composition according to [4], wherein the carbon six-membered ring compound having at least one diglycidylamino group is a compound represented by a specific chemical structural formula.
[6] A pressure-sensitive adhesive sheet, wherein a pressure-sensitive adhesive layer having a thickness of 1 to 200 μm comprising the pressure-sensitive adhesive composition according to [1] is provided on one side or both sides of a substrate.

In addition, the elasticity modulus and adhesive force in this invention are measured as follows.
That is, the elastic modulus was applied to a silicone sheet, dried, peeled off after forming a 50 μm thick adhesive layer, and the adhesive layer was laminated until the thickness reached 200 μm. A sample sheet is fabricated by processing to 0.0 mm and a length of 15.0 mm. One end of the sample sheet in the longitudinal direction is supported by a fixed chuck, and the other end is supported by a movable chuck. Under the set temperature conditions (measurement temperature range: −100 to 300 ° C.) and a load of −0.2 g to −0.5 g (cycle 5 seconds) by TMA tension mode method using MAC Science Co., Ltd. The measurement was performed in an air atmosphere at a heating rate of 5 ° C./min.

  In addition, the adhesive strength is based on JIS Z0237, and after the production, the adhesive sheets of Examples and Comparative Examples, which have not been subjected to heat treatment or ultraviolet irradiation treatment, have a width of 25 mm under an environment of 23 ° C. and 65% RH. A test piece cut to a length of 250 mm is bonded to both sides of a polyimide film having a thickness of 25 μm by reciprocating a rubber roller under the conditions of a pressing force of 2 kg and a speed of 300 mm / min. The test piece was allowed to stand for 20 minutes under the conditions of 65% RH, and the test piece was subjected to 180 ° direction at a tensile speed of 300 mm / min with a tensile tester under the temperature conditions of 23 ° C., 100 ° C., 150 ° C. and 200 ° C. The 180 degree peeling force when the polyimide film was peeled off from the test piece was measured, and this peeling force was taken as the peeling force of the test piece and indicated in unit N / 25 mm.

According to the present invention, it is possible to obtain a pressure-sensitive adhesive composition that does not cause foaming or peeling due to insufficient cohesive force or reduced adhesive strength even when used in a high-temperature environment, particularly with a solder temperature profile. Moreover, the adhesive sheet which made this adhesive composition into the sheet form or the tape form can be used in a high temperature environment. Also, by using this pressure-sensitive adhesive sheet, conventionally, it is easier than forming an adhesive layer by applying a liquid epoxy adhesive or polyimide adhesive to an adherend by spin coating or screen printing. An adhesive layer having a smoothness and a uniform coating thickness can be formed, and productivity, handleability of the adhesive, and workability can be improved. Also, because it has better adhesion to the adherend at room temperature than the case of using an adhesive sheet formed of epoxy resin or hot melt adhesive in sheet form, it can save energy and purchase processing tools such as jigs. Since there is no increase in cost or reduction in work efficiency due to use, it is advantageous in terms of production efficiency.

It is a graph which shows the temperature profile at the time of evaluating the temperature profile applicability of solder.

[Component A]
The component (A) used in the present invention is an acrylic adhesive compound having a mass average molecular weight of 300,000 or more and an acid value of 1 mgKOH / g or more and less than 5 mgKOH / g.

When the mass average molecular weight of the component (A) is less than 300,000, the cohesive force becomes insufficient, and the pressure-sensitive adhesive layer formed using this foams in a high-temperature atmosphere. Therefore, the mass average molecular weight of this component is 300,000 or more. Preferably, it is necessary to be in the range of 400,000 or more, more preferably in the range of 600,000 to 2,000,000. When the mass average molecular weight is 400,000 or more, sufficient cohesive force can be secured and heat resistance is excellent. On the other hand, when the mass average molecular weight exceeds 2 million, workability at the time of processing into a pressure-sensitive adhesive sheet is lowered.

The component (A) needs to have an acid value of 1 mgKOH / g or more and less than 5 mgKOH / g, preferably 1 to 4 mgKOH / g. This is because when the acid value is lower than 1 mgKOH / g, the heat resistance is lowered, and when it is 5 mgKOH / g or more, the peeling force in a high temperature (150 ° C.) atmosphere is lowered.

Examples of the acrylic pressure-sensitive adhesive compound that gives the mass average molecular weight and the acid value include a copolymer of a (meth) acrylic acid alkyl ester and a monomer copolymerizable therewith.
Here, the (meth) acrylic acid alkyl ester means an acrylic acid alkyl ester or a methacrylic acid alkyl ester. Among such (meth) acrylic acid alkyl esters, (meth) acrylic acid alkyl esters having an alkyl group having 1 to 4 carbon atoms, such as (meth) acrylic acid methyl ester, ethyl ester, n- Propyl ester, isopropyl ester, n-butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, etc. When forming the adhesive layer, there is no foaming even in a high temperature environment of 260 ° C. (Meth) acrylic acid alkyl esters having a C2-C4 alkyl group such as (meth) acrylic acid ethyl ester and butyl ester are preferred in that they exhibit good adhesion even under cooling in the environment and after heating. .

  Next, as a monomer copolymerizable with the above (meth) alkyl acid alkyl ester, for example, acrylic acid, methacrylic acid, β-carboxyethyl acrylate, itaconic acid, crotonic acid, fumaric acid, fumaric anhydride, Monomers containing carboxyl groups such as maleic acid, maleic anhydride, butyl maleate, or 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl Acrylate, 4-hydroxybutyl methacrylate, 6-hydroxyhexyl acrylate, 6-hydroxyhexyl methacrylate, 8-hydroxyoctyl acrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl acrylate Lilate, 10-hydroxydecyl methacrylate, 12-hydroxylauryl acrylate, 12-hydroxylauryl methacrylate, (4-hydroxymethylhexyl) -methyl acrylate, chloro-2-hydroxypropyl acrylate, chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate And monomers containing a hydroxyl group, such as diethylene glycol monomethacrylate, caprolactone-modified acrylates, caprolactone-modified methacrylates, polyethylene glycol acrylates, polyethylene glycol methacrylates, polypropylene glycol acrylates, and polypropylene glycol methacrylates.

  In addition, monomers containing amino groups such as aminomethyl acrylate, aminomethyl methacrylate, dimethylaminomethyl acrylate, dimethylaminomethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl acrylate, dimethylaminopropyl methacrylate, Monomers containing an amide group such as acrylamide, methacrylamide, N-acryloylmorpholine, N-substituted acrylamide, N-substituted methacrylamide, and N-vinylpyrrolidone can also be used. Alternatively, monomers containing a maleimide group such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide can be used.

  Other itaconimide groups such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, etc. Containing monomers, N-acryloyloxymethylenesuccinimide, N-methacryloyloxymethylenesuccinimide, N-acryloyl-6-oxyhexamethylenesuccinimide, N-methacryloyl-6-oxyhexamethylenesuccinimide, N-acryloyl-8-oxy Monomers containing succinimide groups such as octamethylene succinimide, N-methacryloyl-8-oxyoctamethylene succinimide, glycidyl acrylate, glycidyl methacrylate Such as monomers containing epoxy groups, such as over bets can also be used. These monomers may be used independently and may be used in combination of 2 or more type. In addition, when a monomer having a functional group capable of reacting with the component (C) described later, such as a carboxyl group or a hydroxyl group, is used as this monomer, the elasticity and adhesiveness of the pressure-sensitive adhesive composition can be adjusted. Convenient from Although the proportion of the (meth) acrylic acid alkyl ester and the copolymerizable monomer depends on the physical properties of the component (A) to be obtained, it is usually 99.9: 0.1 to 99 by mass ratio. : 1 range.

  Thus, as the component (A), a monomer having a functional group capable of copolymerizing with at least one of the alkyl acrylate ester and the alkyl methacrylate ester and capable of reacting with the component (C) described later. Are preferably copolymerized with (meth) acrylic acid alkyl ester, and a copolymer copolymerizable with both the monomer and copolymerizable monomer. You can also Examples of the monomer used at that time include vinyl acetate, styrene, methylstyrene, vinyltoluene, acrylonitrile and the like. The amount used is 0 to 30% by mass, preferably 0 to 10% by mass, based on the total amount of monomers. It is used in the range. This is because the use of these makes it easy to control the cohesion force within a desired range.

  The copolymer of component (A) can be obtained by radical copolymerization of the monomer component. In this case, the copolymerization method can be arbitrarily selected from conventionally used copolymerization methods such as an emulsion polymerization method, a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and a photopolymerization method. Moreover, as a glass transition temperature of (A) component, it is preferable to exist in the range of -70 degreeC-50 degreeC. When the glass transition temperature is higher than 50 ° C., the adhesion between the adherend and the pressure-sensitive adhesive layer decreases near room temperature, and when the glass transition temperature is less than −70 ° C., the adherend and the pressure-sensitive adhesive at high temperatures. Adhesive strength with the layer decreases. From the viewpoint of improving the adhesion between the adherend and the pressure-sensitive adhesive layer at room temperature (23 ° C.) to 260 ° C., the glass transition temperature of the acrylic pressure-sensitive adhesive is particularly preferably −50 ° C. to 0 ° C. .

[B component]
The component (B) used in the present invention is an acrylic adhesive having a mass average molecular weight of 3000 or more, a mass average molecular weight of the component (A) to be combined +200,000 or less, and an acid value of 30 mgKOH / g or more and 200 mgKOH / g or less. It is a sex compound.
By using this (B) component together with the (A) component, the elastic modulus and peeling force can be controlled within a predetermined range over the entire temperature range of 23 to 260 ° C.

When the mass average molecular weight of the component (B) is less than 3000, the cohesive force decreases. When the mass average molecular weight of this component exceeds the mass average molecular weight of the component (A) to be combined +200,000, the compatibility with the acrylic adhesive compound of the component (A) to be combined is lowered. In terms of cohesive force and compatibility, preferably 10,000 or more, the mass average molecular weight of the component (A) to be combined is particularly preferably 50,000 or more, and the mass average molecular weight of the component (A) to be combined is 200,000 or less. It is a range.

Moreover, when the acid value of (B) component is lower than 30 mgKOH / g, even if it reacts with (C) component mentioned later, cohesion force is insufficient, and the flow of the adhesive due to the decrease in elastic modulus at high temperature causes foaming and the like. Cause. When the acid value of this material exceeds 200 mgKOH / g, the pot life of the adhesive layer forming coating solution is shortened. In terms of the cohesive force of the pressure-sensitive adhesive layer when forming the pressure-sensitive adhesive layer, the modulus of elasticity adjustment and the pot life of the pressure-sensitive adhesive layer-forming coating liquid, it is preferably in the range of 40 to 100 mgKOH / g, particularly preferably in the range of 45 to 80 mgKOH / g. is there.

As the acrylic pressure-sensitive adhesive compound satisfying such physical properties, the (meth) acrylic acid alkyl ester mentioned above as the component (A), particularly a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 9 carbon atoms. And a copolymerizable monomer with an acid value satisfying the above range. Examples of the copolymerizable monomer include acrylic acid, methacrylic acid, β-carboxylethyl acrylate, itaconic acid, crotonic acid, fumaric acid, fumaric anhydride, maleic acid, maleic anhydride, and butyl maleate. And the like. These monomers may be used independently and may be used in combination of 2 or more type. Moreover, it is preferable to use a monomer having a functional group capable of reacting with the component (C) described later, because the elastic modulus of the pressure-sensitive adhesive composition can be easily adjusted.

As in the case of the component (A), the component (B) is preferably a copolymer of at least one (meth) acrylic acid alkyl ester described above and a monomer copolymerizable therewith, If desired, it can be copolymerized with both a (meth) acrylic acid alkyl ester and a monomer copolymerizable therewith, and a copolymer using a monomer other than these can also be used.

The proportion of the monomer that can be copolymerized with at least one (meth) acrylic acid alkyl ester depends on the physical properties of the component (B) to be obtained, but is usually 96: 4 to 90 in mass ratio. : 10 range. If it deviates from this range, the cohesive force required as the component (B) cannot be obtained, or conversely, an unnecessarily high acid value is imparted. This component (B) also preferably has a glass transition temperature in the range of -70 ° C to 50 ° C.

The mixing ratio of the component (A) and the component (B) needs to be in the range of 55:45 to 95: 5 by mass ratio. When the component (B) is more than this range, particularly when used in a solder temperature profile, foaming of the pressure-sensitive adhesive composition and peeling from the adherend occur, leading to a decrease in productivity and quality. Moreover, when this adhesive composition is applied to a substrate described later, the coatability deteriorates. Taking into consideration the suppression of foaming of the pressure-sensitive adhesive composition at high temperatures and the adhesion to the adherend, it is preferably in the range of 70:30 to 90:10.

[C component]
The component (C) is selected from the group consisting of an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent and an amino-based crosslinking agent, and undergoes a crosslinking reaction with at least one of the component (A) and the component (B). It is necessary to obtain. These crosslinking agents may be used alone or in combination of two or more.

Examples of the epoxy crosslinking agent include bisphenol A-epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol. Diglycidyl ether, trimethylolpropane triglycidyl ether, diglycidyl aniline, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N′-diglycidylaminomethyl) And cyclohexane. Among these, in particular, when a carbon six-membered ring compound having a glycidylamino group, for example, at least one selected from the following general formulas (1) to (6) is used, the adhesive can be used in a solder temperature profile. The composition is preferable since it is free from foaming and provides an adhesive composition having excellent adhesion to an adherend.

As the isocyanate-based crosslinking agent, any compound having two or more isocyanate groups in the molecule can be used without particular limitation. For example, tolylene diisocyanate, xylylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, Compounds having two isocyanate groups in the molecule such as tetramethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, compounds obtained by addition reaction with polyhydric alcohols such as trimethylolpropane and pentaerythritol, Examples thereof include compounds having isocyanurate bonds obtained by trimerization reaction thereof.

Examples of amino crosslinking agents include melamine crosslinking agents, benzoguanamine crosslinking agents, and urea crosslinking agents.

Examples of the melamine-based crosslinking agent include melamine, a methylolated melamine derivative obtained by condensing melamine and formaldehyde, a compound partially or completely etherified by reacting a methylolated melamine with a lower alcohol, and a mixture thereof. Can be used. Moreover, as a melamine type crosslinking agent, any of the condensate which consists of a monomer and a multimer more than a dimer may be sufficient, and these mixtures may be sufficient. More specifically, imino group type methylated melamine resin, methylol group type melamine resin, methylol group type methylated melamine resin, and completely alkyl type methylated melamine resin are exemplified.

Examples of the benzoguanamine-based crosslinking agent include benzoguanamine, a methylolated benzoguanamine derivative obtained by condensing benzoguanamine and formaldehyde, a compound partially or completely etherified by reacting a methylolated benzoguanamine with a lower alcohol, and a mixture thereof. Can be used. The benzoguanamine-based crosslinking agent may be any of a condensate composed of a monomer, a dimer or a multimer, or a mixture thereof. More specifically, a butylated benzoguanamine resin, a methylolated benzoguanamine resin and the like can be mentioned.

Examples of the urea-based crosslinking agent include methylolated urea derivatives obtained by condensing urea and formaldehyde, compounds partially or completely etherified by reacting methylolated urea with lower alcohol, and mixtures thereof. be able to. Further, the urea-based crosslinking agent may be a monomer or a condensate composed of a dimer or higher polymer, or a mixture thereof. More specific examples include butylated urea resins and methylolated urea resins.

About (C) component, the ratio of the reactive functional group in (C) component is equivalent ratio with respect to the reactive functional group in (A) component and (B) component, for example, the total amount of a carboxyl group and a hydroxyl group. When blended at a ratio of 0.5 to 6 times, preferably 1 to 3 times, it is advantageous because a high elastic modulus can be maintained even at high temperatures.
When the amount of the component (C) is less than the above proportion, the cohesive force is insufficient and the heat resistance becomes insufficient, and when it exceeds the above proportion, the unreacted component (C) which is a low molecular weight component. Therefore, the pressure sensitive adhesive fluidizes at a high temperature, resulting in insufficient heat resistance.

Next, the pressure-sensitive adhesive composition of the present invention is characterized by exhibiting an elastic modulus of 0.1 to 3 MPa and an adhesive force of 0.1 N / 25 mm or more over the entire temperature range of 23 to 260 ° C. .
By using together the component (A) and the component (B) in the pressure-sensitive adhesive composition of the present invention, the elastic modulus can be controlled within the above range over the entire temperature range of 23 to 260 ° C., and (A The adhesive strength can be controlled within the above range by using a low acid value acrylic adhesive compound as a component.

When the elastic modulus of the pressure-sensitive adhesive composition is lower than the above range, when processed into a pressure-sensitive adhesive sheet, when heated to a solder temperature, the pressure-sensitive adhesive composition is bonded to the adherend by foaming of the pressure-sensitive adhesive layer based on lack of cohesive force. If the temperature is higher than the above range, adhesion to an adherend is lacking even in an atmosphere at 23 ° C., and the peeling force particularly under heating deteriorates.
On the other hand, if the adhesive strength is less than 0.1 N / 25 mm, the adhesiveness with the adherend is lacking and adhesion abnormality occurs.

  Moreover, the pressure-sensitive adhesive composition of the present invention is such that the ratio (X) / (Y) of the elastic modulus (X) at 23 ° C. and the elastic modulus (Y) at 260 ° C. is between 0.5 and 10. It is necessary to select the composition. By selecting in this way, it becomes possible to suppress foaming of the adhesive layer at a high temperature when processed into a pressure-sensitive adhesive sheet, and to suppress blistering between the adherend and decrease in adhesion.

  In the pressure-sensitive adhesive composition of the present invention, various conventionally used additives such as a tackifier resin, a crosslinking accelerator, an antioxidant, a stabilizer, a viscosity modifier, or an organic or inorganic filling are used as desired. An agent or the like can be added. Preferable examples of the antioxidant include phenolic antioxidants, organic fillers such as acrylic or urethane spherical fine particles, and inorganic fillers such as silica, calcium carbonate, and alumina. it can.

Adjustment of the elastic modulus and adhesive strength in the pressure-sensitive adhesive composition of the present invention is performed by increasing or decreasing the blending ratio of the component (C) and its crosslinking rate.
If the amount of the component (C) is increased or the crosslinking rate is increased, the elastic modulus is increased and the adhesive strength is decreased. If the amount of the component (C) is decreased or the crosslinking rate is decreased, the modulus of elasticity is increased. The adhesive strength is improved with lowering.

  Next, in order to produce a pressure-sensitive adhesive sheet using the above-mentioned pressure-sensitive adhesive composition, it may be applied on a substrate having releasability, or on one or both surfaces of a substrate having no releasability. An adhesive layer-forming coating solution containing this adhesive composition may be applied.

The constituent material of the base material constituting the pressure-sensitive adhesive sheet is not particularly limited, and can be appropriately selected from materials conventionally used as a base material for pressure-sensitive adhesive sheets according to the use of the pressure-sensitive adhesive sheet. Specifically, synthetic resins such as polyethylene terephthalate, polyethylene naphthalate, polyethylene, polypropylene, polycarbonate, triacetyl cellulose, cellophane, polyimide, polyamide, polyphenylene sulfide, polyetherimide, polyethersulfone, aromatic polyamide, or polysulfone, It can be selected from glass, metal, ceramic and the like.
These substrates may be transparent or colored. Coloring can be performed by a method of blending various pigments and dyes into the constituent material of the substrate. Further, the surface of the substrate does not need to be smooth, and the surface may be processed into a mat shape.

  Moreover, when using the sheet | seat which has mold release property as a base material, what provided the resin layer which has mold release characteristics, such as a silicone type resin and a polypropylene resin, etc. can be used at least on one side, for example.

  The base material contains a conventionally known additive, specifically a heat resistance stabilizer, an oxidation resistance stabilizer, a weather resistance stabilizer, an ultraviolet absorber, an antistatic agent, etc. in the constituent material. Also good. Moreover, it is preferable to use what gave surface treatment for the purpose of improving adhesiveness with an adhesion layer. Examples of the surface treatment include discharge treatment such as corona discharge treatment and glow discharge treatment, plasma treatment, flame treatment, ozone treatment, ultraviolet treatment, electron beam treatment, radiation treatment, and other ionizing active ray treatment, sand mat treatment, anchor Examples thereof include surface roughening treatment such as treatment, hairline treatment, chemical treatment, and easy adhesion layer coating treatment. The thickness of the substrate may be appropriately selected according to the application field of the pressure-sensitive adhesive sheet, but is usually 12 to 250 μm, and preferably 25 to 150 μm from the viewpoint of followability to the adherend and transportability.

  The thickness of the adhesive layer is not particularly limited, but is preferably 1 to 200 μm, more preferably 2 to 100 μm, and particularly preferably 20 to 50 μm. When the thickness of the pressure-sensitive adhesive layer is less than the above range, it is not preferable because sufficient adhesion to the adherend cannot be obtained. When the thickness of the pressure-sensitive adhesive layer exceeds the above range, it is not preferable because it results in poor drying.

  For example, the pressure-sensitive adhesive layer is prepared by dissolving or dispersing the pressure-sensitive adhesive composition in an appropriate solvent to obtain a pressure-sensitive adhesive layer-forming coating solution having a solid content concentration of about 10 to 50% by mass. According to a conventional method, the liquid can be obtained by applying it so as to cover at least one surface of the substrate and drying it.

  At this time, the adhesive layer-forming coating liquid may be prepared by adding various conventionally used additives, for example, a crosslinking accelerator, an antioxidant, a stabilizer, a viscosity modifier, a tackifier resin, or an organic or inorganic as desired. The filler can be added. Examples of the crosslinking accelerator include triethylamine-based, cobalt naphthenate-based, and tin-based crosslinking accelerators, and in particular, stannous chloride, tetra-n-butyltin, trimethyltin hydroxide, dimethyltin chloride, dilaurate. It is preferable to use a tin-based crosslinking accelerator such as -n-butyltin. In addition, as antioxidants, phenolic antioxidants, etc., as tackifier resins, terpene resins, etc., as organic fillers, acrylic or urethane spherical fine particles, etc. as inorganic fillers are used. Silica, calcium carbonate, alumina and the like can be preferably used.

  There are no particular restrictions on the method of application, and conventionally known applications using wire bars, applicators, brushes, sprays, rollers, gravure coaters, die coaters, lip coaters, comma coaters, knife coaters, reverse coaters, spin coaters, etc. The method can be used. In addition, the surface of the base material to which the adhesive layer-forming coating solution is applied or the surface of the film having releasability can be subjected to surface treatment in advance as necessary.

  There is no restriction | limiting in particular also about a drying method, Conventionally well-known drying methods, such as hot air drying and reduced pressure drying, can be utilized. About drying conditions, what is necessary is just to set suitably according to the kind of adhesive, the kind of solvent used with coating liquid, the film thickness of an adhesion layer, etc., but it is common to dry at the temperature of about 60-180 ° C. Is. In the case where the raw material composition has a crosslinkable composition, the raw material composition can be crosslinked by this heating.

  Depending on the amount of volatile matter remaining in the adhesive layer (hereinafter referred to as “residual volatile matter amount”), the adhesiveness between the adhesive layer and the substrate or the peelability after cooling may be adversely affected. In particular, vaporization of residual volatile components at high temperatures may cause foaming and peeling. Accordingly, the residual volatile content in the adhesive layer is preferably 4% by mass or less, particularly preferably 2% by mass or less. In order to obtain the desired residual volatile content, the amount of solvent for preparing the adhesive layer forming coating solution, the drying time after coating, and the like are adjusted.

Hereinafter, although the adhesive composition of this invention and an adhesive sheet are demonstrated concretely using an Example, this invention is not limited at all by these.
The physical properties in each example were evaluated by the following methods.

(1) Elastic modulus (MPa)
The pressure-sensitive adhesive composition is applied onto a silicone sheet and dried to form a pressure-sensitive adhesive layer having a thickness of 50 μm, and then the peeling operation is repeated, and the pressure-sensitive adhesive layer is laminated until the thickness reaches 200 μm. Next, the pressure-sensitive adhesive layer is cut into a width of 3.0 mm and a length of 15.0 mm to produce a sample sheet. One end of the sample sheet in the longitudinal direction is supported by a fixed chuck, and the other end is supported by a movable chuck. In the air atmosphere by TMA tension mode using TMA4000S (manufactured by MAC Science). Under the respective set temperature conditions in the range of −100 ° C. to 300 ° C., a load of −0.2 to −0.5 g was applied at a cycle of 5 seconds, and the rate of temperature increase was measured at 5 ° C./min. In addition, the notation of x in Table 3 indicates that the elastic modulus was remarkably lowered at the time of measurement, and the test piece was completely stretched and could not be measured.

(2) Adhesive strength (N / 25mm)
By the method according to JIS Z0237, the pressure-sensitive adhesive sheets of Examples and Comparative Examples, which were not subjected to heat treatment or ultraviolet irradiation treatment after production, were made 25 mm wide and 250 mm long in an environment of 23 ° C. and 65% RH. A test piece was prepared by pressing a polyimide film having a thickness of 25 μm on both sides of the cut test piece by reciprocating a rubber roller under a pressure of 2 kg and a speed of 300 mm / min. The test piece was left for 20 minutes under the conditions of 23 ° C. and 65% RH, and then the test piece was placed under the temperature conditions of 23 ° C., 100 ° C., 150 ° C., and 200 ° C. with a tensile tester at a tensile rate of 300 mm / In minutes, the 180 ° peel force when the polyimide film was peeled from the test piece in the 180 ° direction was measured, and this peel force was defined as the adhesive strength of the test piece.
In addition, the polyimide film used the Toray DuPont Films company make and brand name: Kapton 100V (thickness 25 micrometers).

(3) Profile applicability at soldering temperature After manufacturing, the adhesive sheets of Examples and Comparative Examples, which were not subjected to heat treatment or ultraviolet irradiation treatment, had a width of 50 mm and a length of 50 mm in an environment of 23 ° C. and 65% RH. The polyimide surface of the non-adhesive type copper clad laminate (manufactured by Nippon Steel Chemical Co., Ltd., product name: Espanex SC12-25-00AE) and the polyimide film (manufactured by Toray DuPont Films, Inc., trade name: Kapton 500H ( And laminated with a laminator at a temperature of 23 ° C., a speed of 1 m / min, and a pressure of 0.3 MPa, and then heated to 110 ° C. and heated, and at that temperature for 1 hour After standing (after cure), put it in a reflow oven with a peak temperature of 260 ° C and observe the adhesive state of the adhesive layer to check for adhesive abnormalities such as bubbles, floats, wrinkles, peeling, and misalignment. The presence or absence of occurrence was evaluated visually according to the following criteria.
In addition, according to the temperature profile shown in FIG. 1, after the after cure, a reflow furnace was used, and it was performed at about 150 ° C. × 60 seconds to 260 ° C. × 30 seconds in an air environment.
○: No change in appearance.
X: Although bubbles (adhesion abnormality) were partially observed, there was no peeling of the polyimide film, and no irregularities were confirmed from the copper foil surface of the copper-clad laminate.
XX: Bubbles (adhesion abnormality) are observed on the entire surface. Air bubbles were generated between the polyimide film and the copper-clad laminate, and irregularities were also confirmed from the copper foil surface of the copper-clad laminate.

  (A) component, (B) component, and (C) component used by each Example and the comparative example are as follows.

Component (A1): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 900,000, an acid value of 1 mgKOH / g, and a glass transition temperature of -22 ° C.

Component (A2): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 900,000, an acid value of 2 mgKOH / g, and a glass transition temperature of -22 ° C.

Component (A3): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 900,000, an acid value of 3 mgKOH / g, and a glass transition temperature of -22 ° C.

Component (A4): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 900,000, an acid value of 4 mgKOH / g, and a glass transition temperature of -22 ° C.

Component (A5): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 900,000, an acid value of 8 mgKOH / g, and a glass transition temperature of -22 ° C.

Component (A6): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 400,000, an acid value of 3 mg KOH / g, and a glass transition temperature of −22 ° C.

Component (A7): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 600,000, an acid value of 3 mgKOH / g, and a glass transition temperature of −22 ° C.

(A8) Component: Ethyl acrylate, a copolymer of n-butyl acrylate and acrylic acid, having a weight average molecular weight of 900,000, an acid value of 3 mgKOH / g, and a glass transition temperature of -37 ° C.

Component (A9): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 100,000, an acid value of 3 mgKOH / g, and a glass transition temperature of -22 ° C.

Component (B1): a copolymer of methyl acrylate, 2-ethylhexyl acrylate and acrylic acid, having a mass average molecular weight of 300,000, an acid value of 47 mg KOH / g, and a glass transition temperature of -7 ° C.

Component (B2): a copolymer of n-butyl acrylate and acrylic acid, having a mass average molecular weight of 500,000, an acid value of 78 mgKOH / g, and a glass transition temperature of −45 ° C.

Component (B3): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 900,000, an acid value of 47 mgKOH / g, and a glass transition temperature of -17 ° C.

Component (B4): A copolymer of ethyl acrylate and acrylic acid, having a mass average molecular weight of 50,000, an acid value of 78 mgKOH / g, and a glass transition temperature of -13 ° C.

(C1) Component: Epoxy crosslinking agent composed of N, N, N ′, N′-tetraglycidyl-m-xylenediamine, epoxy equivalent of 95 to 105, tetrafunctional.

(C2) Component: An epoxy-based crosslinking agent composed of 3-bis (N, N′-diglycidylaminomethyl) cyclohexane, an epoxy equivalent of 100 to 110, and tetrafunctional.

Component (C3): epoxy-based crosslinking agent composed of diglycidyl toluidine, epoxy equivalent 133, bifunctional.

Component (C4): Isocyanate-based crosslinking agent (Evonik Degussa, product name VESTANAT T1890).

(C5) Ingredient: Amino-based crosslinking agent (manufactured by DIC, product name Beccamin G-1850)

(Tackifying resin): Alkylphenol-modified xylene resin, softening point 165 ° C., hydroxyl value 170 mgKOH / g, mass average molecular weight 1400.

Example 1
(A1) 90 parts by mass of component, (B2) 10 parts by mass of component, and (C1) 440 parts by mass of methyl isobutyl ketone are added to an adhesive composition comprising 4.7 parts by mass, followed by stirring and mixing to form an adhesive layer. A coating solution was prepared.
Next, this coating solution is applied to the surface of a release film (silicone-treated polyethylene terephthalate) having a thickness of 100 μm using a baker type applicator, 3 minutes at 80 ° C., then 1 minute at 130 ° C., and 180 An adhesive layer having a thickness of 50 μm was formed by drying at 1 ° C. for 1 minute. Another adhesive film (silicone-treated polyethylene terephthalate) having a thickness of 100 μm was attached to the opposite side of the adhesive layer from the release film, and cured at 40 ° C. for 7 days to prepare an adhesive sheet. The physical properties of this product are shown in Table 1.

Examples 2-10
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 using the pressure-sensitive adhesive composition having the composition shown in Table 1. Table 1 shows the physical properties of these pressure-sensitive adhesive sheets.

Examples 11-17
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 using the pressure-sensitive adhesive compositions having the compositions shown in Table 2. Table 2 shows the physical properties of these pressure-sensitive adhesive sheets.

Comparative Examples 1-9
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 using the pressure-sensitive adhesive compositions having the compositions shown in Table 3. Table 3 shows the physical properties of these pressure-sensitive adhesive sheets.

From the results of Tables 1 and 2, in Examples 1 to 17, the TMA viscoelastic modulus was in the range of 0.1 to 3 MPa at any temperature of 23 to 260 ° C., and the elastic modulus ratio was also 0.1. It is in the range of 5-10. Furthermore, it turns out that the peeling force (N / 25mm) in 23-200 degreeC is 0.1 N / 25mm or more.
As a result, it can be seen that the pressure-sensitive adhesive sheet of the example does not cause foaming of the pressure-sensitive adhesive layer in the solder temperature profile applicability evaluation, and does not float or peel off the adherend.
From this result, it can be presumed that the pressure-sensitive adhesive sheet of Examples 1 to 17 is a pressure-sensitive adhesive sheet that can be sufficiently used even in an operation with a solder reflow process by using it for sticking a reinforcing plate when manufacturing a flexible printed circuit board.

  Further, in Example 1, an adhesion abnormality occurs when the solder temperature profile applicability evaluation (reflow) is performed by mixing a low acid value (A1) component and a high acid value (B2) component as an acrylic pressure-sensitive adhesive. There wasn't.

  In Example 2, the (A1) component of Example 1 is changed to the (A3) component, and the (B2) component is changed to the (B1) component. As a result, the elastic modulus ratio is lower than that in Example 1. Even in this case, no adhesion abnormality occurred during reflow.

  Examples 3 and 4 are obtained by adding a tackifying resin to Example 2. As a result, both the elastic modulus ratio and the peeling force were larger than those in Example 2. Even in this case, no adhesion abnormality occurred during reflow.

  In Example 5, the (A3) component of Example 2 is changed to the (A4) component. As a result, the elastic modulus ratio is lower than that in Example 2. Even in this case, no adhesion abnormality occurred during reflow.

  In Examples 6 and 7, the component (A3) in Example 2 was changed to components (A6) and (A7), respectively. Although the elastic modulus of this pressure-sensitive adhesive sheet was lower than that of Example 2, no adhesion abnormality occurred during reflow.

  In Example 8, the (C1) component of Example 2 was changed to the (C2) component. Although the elastic modulus of this pressure-sensitive adhesive sheet is substantially the same as that of Example 2, it can be seen that the peel strength at 23 ° C. is high, and the adhesion to the adherend at room temperature is good.

  In Example 9, the crosslinking agent (C1) component of Example 2 was changed to the (C3) component. This shows that the temperature dependence of the elastic modulus is small compared to the others, and the peel force is as high as 1 N / 25 mm or more at each temperature.

  In Example 10, the component (B1) in Example 7 is changed to the component (B2). It can be seen that the elastic modulus of this pressure-sensitive adhesive sheet is somewhat higher than that of Example 7, and the peel force is somewhat lower.

  In Example 11, the blending amounts of the components (A3), (B1), and (C1) in Example 2 are changed. It can be seen that the elastic modulus of this pressure-sensitive adhesive sheet is higher than that of Example 2, and the peeling force is low except at 23 ° C.

  Example 12 changes the compounding quantity of (C1) component of Example 2. FIG. It can be seen that this has a somewhat lower elastic modulus than Example 2.

  Example 13 changes the compounding quantity of (C1) component of Example 2. FIG. It can be seen that this has a somewhat higher elastic modulus than Example 2.

  In Example 14, the component (A3) in Example 2 was changed to the component (A8). This shows that the elastic modulus is somewhat lower than that of Example 2, but the peel strength is high.

  In Example 15, the (C1) component of Example 2 was changed to the (C4) component. This material has a higher elastic modulus ratio because it has a higher elastic modulus at 23 ° C. than other materials, but no adhesion or more occurred during reflow.

  In Example 16, the component (C1) in Example 2 was changed to the component (C5). This material has a slightly smaller elastic modulus and peeling force than other materials, but no adhesion abnormality occurred during reflow.

  In Example 17, the component (B1) in Example 2 is changed to the component (B4). This material has a slightly smaller elastic modulus than the others, but no adhesion abnormality occurred during reflow.

In Comparative Example 1 shown in Table 3, the component (B2) in Example 1 is changed to the component (B1).
This had a lower elastic modulus than that of Example 1 and could not be measured particularly after 150 ° C. It can be seen that, due to the decrease in the elastic modulus, foaming occurs in the adhesive layer or the adherend is lifted off in the appropriate evaluation (reflow) of the solder temperature profile.

  The comparative example 2 changes the (A3) component of Example 2 into the (A2) component. This had a lower elastic modulus than that of Example 2 and could not be measured particularly after 200 ° C. It can be seen that, due to the decrease in the elastic modulus, foaming occurs in the adhesive layer in the proper evaluation of the temperature profile of the solder, and the adherend is lifted off.

  In Comparative Example 3, the amount of the tackifying resin of Example 3 was changed. This has an elastic modulus that is not in the range of 0.1 to 3 MPa, and the elastic modulus ratio is very large. Furthermore, the peeling force shows a value smaller than 0.1 N / 25 mm at 200 ° C. From these facts, it can be seen that foaming occurs in the adhesive layer in the proper evaluation of the temperature profile of the solder, and that the adherend is lifted off.

  In Comparative Example 4, the amount of the tackifying resin in Comparative Example 3 is changed. This had a lower elastic modulus and could not be measured particularly after 100 ° C. It can be seen that, due to the decrease in the elastic modulus, foaming occurs in the adhesive layer in the proper evaluation of the temperature profile of the solder, and the adherend is lifted off.

  The comparative example 5 changes the compounding quantity of the (A3), (B1), and (C1) component of Example 2. The elastic modulus after 150 ° C. exceeds 3 MPa, and the peeling force at a temperature of 100 ° C. or higher shows a value of 0.1 N / 25 mm or lower. From this, it can be seen that foaming occurs in the adhesive layer in the proper evaluation of the temperature profile of the solder, and that the adherend is lifted off.

  In Comparative Example 6, the component (A2) in Example 2 is changed to the component (A5). This has an elastic modulus in the range of 0.1 to 3 MPa in any temperature range and an elastic modulus ratio in the range of 0.5 to 10, but the peel force at temperatures of 100 ° C. and 150 ° C. Indicates a value of 0.1 N / 25 mm or less. From this, it can be seen that in the proper evaluation of the temperature profile of the solder, foaming is partially generated in the adhesive layer or the adherend is lifted off.

  Comparative Example 7 is an example in which the molecular weight of the B component is higher than the molecular weight of the A component + 200,000. This has an elastic modulus in the range of 0.1 to 3 MPa in any temperature range and an elastic modulus ratio in the range of 0.5 to 10, but the peel force at a temperature of 150 ° C. is 0. A value of 1 N / 25 mm or less is shown. From this, it can be seen that in the proper evaluation of the temperature profile of the solder, foaming is partially generated in the adhesive layer or the adherend is lifted off.

  The comparative example 8 changes the compounding quantity of the (C1) component of Example 2. FIG. It can be seen that this has a lower elastic modulus at 260 ° C. and a significantly lower peel force at a temperature of 100 ° C. or higher than Example 2. From this, it can be seen that foaming occurs in the adhesive layer in the proper evaluation of the temperature profile of the solder, and that the adherend is lifted off.

  In Comparative Example 9, the component (A3) in Example 2 is changed to the component (A9). This shows that the elastic modulus at 200 ° C. or higher is remarkably lowered as compared with Example 2. From this, it can be seen that foaming occurs in the adhesive layer in the proper evaluation of the temperature profile of the solder, and that the adherend is lifted off.

  INDUSTRIAL APPLICABILITY The present invention can be used as a pressure sensitive adhesive sheet such as a mask material for soldering process, a chip, various capacitors, a battery, a printed circuit board, transportation during manufacture, a backup, a plating mask, and a mask when baking various vehicles. . In particular, it is used as a pressure-sensitive adhesive sheet used when laminating a reinforcing plate (stiffener) on the surface of a flexible printed circuit board on which electronic components such as chips and capacitors are mounted and on the surface opposite to the circuit portion of a connector portion such as a power supply. be able to.

Claims (6)

(A) an acrylic adhesive compound having a mass average molecular weight of 300,000 or more and an acid value of 1 mgKOH / g or more and less than 5 mgKOH / g,
(B) Acrylic adhesive compound having a weight average molecular weight of 3000 or more, a weight average molecular weight of component (A) to be combined +200,000 or less, an acid value of 30 mgKOH / g or more and 200 mgKOH / g or less, and (C) an epoxy crosslinking agent , Comprising at least one crosslinking agent selected from the group consisting of isocyanate crosslinking agents and amino crosslinking agents,
The blending ratio of the component (A) and the component (B) is in the range of 55:45 to 95: 5, and the elastic modulus is 0.1 to 3 MPa and the adhesive strength is 0.1 N / over the entire temperature range of 23 to 260 ° C. A pressure-sensitive adhesive characterized by having a ratio (X) / (Y) of 25 mm or more and an elastic modulus (X) at 23 ° C. and an elastic modulus (Y) at 260 ° C. of 0.5 to 10 Agent composition. The (A) component is a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms and a monomer having a reactive functional group for the (C) component, (B ) Component is a copolymer of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 9 carbon atoms and a monomer having a reactive functional group for the component (C), and component (A) And the component (B) has a glass transition temperature in the range of -70 ° C to 50 ° C. The ratio of the reactive functional group in the component (C) is 0.5 to 6 times in terms of equivalent ratio with respect to the total amount of the reactive functional group in the adhesive compound of the component (A) and the component (B). The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition according to claim 1, wherein the component (C) is a carbon six-membered ring compound having at least one diglycidylamino group. The pressure-sensitive adhesive composition according to claim 4, wherein the carbon six-membered ring compound having at least one diglycidylamino group is a compound represented by any one of the following chemical structural formulas (1) to (6).






















(6)


A pressure-sensitive adhesive sheet, wherein a pressure-sensitive adhesive layer having a thickness of 1 to 200 μm comprising the pressure-sensitive adhesive composition according to claim 1 is provided on one side or both sides of a substrate.