Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J153/00—Adhesives based on block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
  • C09J153/02—Vinyl aromatic monomers and conjugated dienes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J163/00—Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins

Definitions

• the present disclosure relates to an adhesive composition, a laminate with an adhesive layer, a flexible copper-clad laminate, and a flexible flat cable. More specifically, the present disclosure relates to an adhesive composition suitable for bonding electronic components and the like, particularly for the manufacture of products related to flexible printed wiring boards, a laminate with an adhesive layer using the same, and a flexible copper-clad laminate and a flexible flat cable using the same.
• FPCs Flexible printed circuit boards
• coverlay film When manufacturing the FPC, a laminate with an adhesive layer, called a "coverlay film,” is usually used to protect the wiring portion.
• This coverlay film comprises an insulating base film and an adhesive layer formed on its surface, with polyimide resin being widely used as the material for the base film.
• a flexible printed wiring board is then manufactured by attaching the coverlay film via the adhesive layer to the surface having the wiring portion, for example, using a heat press or the like. At this time, the adhesive layer of the coverlay film needs to have strong adhesion to both the wiring portion and the base film.
• Epoxy adhesive compositions containing an epoxy resin and a thermoplastic resin that is reactive with this epoxy resin are widely used as adhesive compositions for such FPC-related products.
• adhesive compositions that have easy peelability and strong adhesion to FPCs have also been proposed, such as adhesive compositions that are made by mixing a conductive filler with a resin component that is composed of a flame-retardant resin that has been given flame retardancy to an epoxy adhesive and a crosslinking agent.
• the adhesive compositions described above are generally used to bond desired substrates together, and are often used in layers from the viewpoint of production, etc.
• a B-stage adhesive layer formed from the adhesive composition is bonded to the desired substrate. If misalignment occurs during this bonding, it becomes necessary to peel the adhesive layer from the adherend and readjust the position. Furthermore, if the adhesive layers accidentally come into contact and stick to each other during the bonding process, it is necessary to be able to peel them off easily. For this reason, the adhesive composition is required to be removably.
• the present disclosure has been made in consideration of such problems, and aims to provide an adhesive composition that can improve removability without using a filler, a laminate with an adhesive layer that uses the same, and a flexible copper-clad laminate or flexible flat cable that uses the same.
• [1] Contains a styrene-based resin (A) and an epoxy resin (B),
• the styrene-based resin (A) contains a styrene-ethylene-butylene/styrene-styrene copolymer (A2), the content of the styrene-ethylene-butylene/styrene-styrene copolymer (A2) is 3 parts by mass or more and 99.9 parts by mass or less per 100 parts by mass of the resin component,
• the content of the modified resin which is a resin having a reactive functional group that reacts with an epoxy group introduced therein, is 25 parts by mass or more and 99.9 parts by mass or less out of 100 parts by mass of the resin component.
• Adhesive composition [2] The styrene content of the styrene-ethylene-butylene/styrene-styrene copolymer (A2) is 40% by mass or more. The adhesive composition according to the above [1]. [3] The styrene-based resin (A) further contains a styrene-based elastomer (A1). The adhesive composition according to the above [1] or [2]. [4] The reactive functional group is introduced at least into the styrene-ethylene-butylene/styrene-styrene copolymer (A2). The adhesive composition according to any one of the above [1] to [3].
• a flexible copper-clad laminate comprising the adhesive layer-attached laminate according to the above-mentioned [7], the base film being provided on one side of the adhesive layer, and a copper foil being provided on the other side of the adhesive layer.
• a flexible flat cable comprising the base film on one side of the adhesive layer in the laminate with an adhesive layer according to [7] above, and a copper wiring on the other side of the adhesive layer.
• the adhesive layer of the laminate with adhesive layer is formed using the adhesive composition with good removability. Therefore, even if the adhesive layer of the laminate with adhesive layer is misaligned when it is bonded, the adhesive layer can be easily peeled off from the adherend and repositioned. Furthermore, even if the adhesive layers of the laminate with adhesive layer accidentally come into contact with each other and stick to each other during the bonding operation, the two can be easily peeled off.
• the flexible copper-clad laminate has the above-mentioned configuration. Therefore, the flexible copper-clad laminate can suppress the deterioration of the adhesive layer's adhesion and solder heat resistance due to the deterioration of filler dispersion by reducing the filler in the adhesive layer, and also makes it difficult for filler aggregates to occur, making it possible to reduce the thickness of the adhesive layer.
• Adhesive Composition contains a styrene-based resin (A) and an epoxy resin (B), and the styrene-based resin (A) contains a styrene-ethylene-butylene/styrene-styrene copolymer (A2).
• the adhesive composition of this embodiment contains styrene-ethylene-butylene/styrene-styrene copolymer (A2) in an amount of 3 parts by mass or more and 99.9 parts by mass or less per 100 parts by mass of the resin component, and contains a modified resin, which is a resin having a reactive functional group that reacts with an epoxy group introduced therein, in an amount of 25 parts by mass or more and 99.9 parts by mass or less per 100 parts by mass of the resin component.
• A2 styrene-ethylene-butylene/styrene-styrene copolymer
• the styrene-ethylene-butylene/styrene-styrene copolymer (A2) may be a modified styrene-ethylene-butylene/styrene-styrene copolymer (modified SEBSS) into which a reactive functional group that reacts with an epoxy group has been introduced in whole or in part, which will be described in detail in relation to the modified resin described later.
• modified SEBSS modified styrene-ethylene-butylene/styrene-styrene copolymer
• the styrene content of the styrene-ethylene-butylene/styrene-styrene copolymer (A2) is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, even more preferably 55% by mass or more, and most preferably 60% by mass or more, from the viewpoint of ensuring adhesion when the adhesive layer in the B stage is bonded.
• the styrene-based resin (A) may further contain a styrene-based elastomer (A1) (excluding the above-mentioned styrene-ethylene-butylene/styrene-styrene copolymer (A2)).
• A1 styrene-based elastomer
• styrene-based elastomers include styrene-butadiene block copolymers (SB), styrene-ethylene propylene block copolymers (SEP), styrene-butadiene-styrene block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS), styrene-ethylene butylene-styrene block copolymers (SEBS), styrene-ethylene propylene-styrene block copolymers (SEPS), and styrene-(ethylene-ethylene/propylene)-styrene block copolymers (SEEPS).
• SB styrene-butadiene block copolymers
• SEP styrene-ethylene propylene block copolymers
• SBS styrene-butadiene-styrene block copoly
• the styrene-based elastomer (A1) may be a modified styrene-based elastomer in which a reactive functional group that reacts with an epoxy group has been introduced into the styrene-based elastomer (A1), in whole or in part, but this will be described in detail in relation to the modified resin described below.
• styrene polymer components include, for example, polystyrene. These styrene polymer components may be used alone or in combination of two or more types.
• the epoxy resin (B) is a component that reacts with a reactive functional group that reacts with an epoxy group, such as a carboxy group, contained in the modified resin described below, and that imparts adhesion to an adherend and heat resistance to a cured product of the adhesive composition.
• examples of the epoxy resin (B) include brominated bisphenol A type epoxy resin, phosphorus-containing epoxy resin, dicyclopentadiene skeleton-containing epoxy resin, naphthalene skeleton-containing epoxy resin, anthracene type epoxy resin, tertiary butyl catechol type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, biphenyl type epoxy resin, bisphenol S type epoxy resin, etc.
• These epoxy resins (B) may be used alone or in combination of two or more.
• epoxy resins (B) epoxy resins without glycidylamino groups are preferred. This is because the storage stability of the laminate with the adhesive layer is improved.
• polyfunctional epoxy resins with alicyclic skeletons are preferred, and epoxy resins with dicyclopentadiene skeletons are more preferred, since they provide an adhesive composition with excellent dielectric properties.
• epoxy resin (B) one having two or more epoxy groups in one molecule is preferred. This is because it is possible to form a crosslinked structure by reacting with the modified resin described below, thereby achieving high heat resistance. Furthermore, when an epoxy resin having two or more epoxy groups is used, the degree of crosslinking with the modified resin described below is sufficient, resulting in sufficient heat resistance.
• the modified resin is a resin in which a reactive functional group that reacts with an epoxy group is introduced among the resin components in the adhesive composition.
• the modified resin may be a styrene-based resin (A) in which a reactive functional group is introduced, or a resin component other than the styrene-based resin (A) and the epoxy resin (B) (hereinafter referred to as resin component (C)) in which a reactive functional group that reacts with an epoxy group is introduced.
• the modified resin is a resin that does not contain the epoxy resin (B). The amount of the resin component in the adhesive composition that needs to be modified will be described later.
• Reactive functional groups that react with epoxy groups include groups having active hydrogen, active ester groups, etc., and examples of groups having active hydrogen include carboxy groups, amino groups, hydroxyl groups, acid anhydride groups, and thiol groups. These can be used alone or in combination of two or more. From the standpoint of reactivity, etc., the reactive functional groups that react with epoxy groups are preferably carboxy groups and amino groups, and more preferably carboxy groups.
• the modified resin is a styrene-based resin (A) to which a reactive functional group has been introduced
• the reactive functional group can be introduced into at least all or part of the styrene-ethylene-butylene/styrene-styrene copolymer (A2). In this case, it becomes easier to ensure removability when bonding the B-stage adhesive layer and peel adhesion strength of the laminate formed using the adhesive composition.
• Reactive functional groups that react with epoxy groups can be introduced by modifying the unmodified desired resin (including elastomers, omitted below) with a modifying agent.
• the modified resin can be said to be a resin in which the unmodified desired resin has been modified with a modifying agent having a reactive functional group that reacts with epoxy groups.
• the modified resin can be a resin that has a portion derived from the unmodified desired resin and a graft portion derived from the modifying agent, and is preferably a resin in which the unmodified desired resin has been graft-modified with a modifying agent containing an ⁇ , ⁇ -unsaturated carboxylic acid or a derivative thereof.
• the modifier may include ⁇ , ⁇ -unsaturated carboxylic acids and their derivatives.
• ⁇ , ⁇ -unsaturated carboxylic acids include maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, aconitic acid, and norbornene dicarboxylic acid.
• derivatives of unsaturated carboxylic acids include acid anhydrides, acid halides, amides, imides, and esters.
• itaconic anhydride, maleic anhydride, aconitic anhydride, and citraconic anhydride are preferred, and itaconic anhydride and maleic anhydride are particularly preferred in terms of adhesiveness.
• a modifier when used, it is sufficient to use one or more selected from ⁇ , ⁇ -unsaturated carboxylic acids and their derivatives, and it may be a combination of one or more ⁇ , ⁇ -unsaturated carboxylic acids and one or more derivatives thereof, a combination of two or more ⁇ , ⁇ -unsaturated carboxylic acids, or a combination of two or more derivatives of ⁇ , ⁇ -unsaturated carboxylic acids.
• the modifying agent may contain other compounds (other modifying agents) in addition to the ⁇ , ⁇ -unsaturated carboxylic acid, etc., depending on the purpose.
• the other compounds (other modifying agents) include (meth)acrylic acid esters represented by the following formula (1), (meth)acrylic acid, other (meth)acrylic acid derivatives, aromatic vinyl compounds, cyclohexyl vinyl ether, etc. These other compounds may be used alone or in combination of two or more.
• CH2 CR1COOR2 ( 1 ) (In formula (1), R 1 is a hydrogen atom or a methyl group, and R 2 is a hydrocarbon group.)
• R 1 is a hydrogen atom or a methyl group, preferably a methyl group.
• R 2 is a hydrocarbon group, preferably an alkyl group having 8 to 18 carbon atoms.
• the modified resin can have at least a graft portion derived from the modifying agent.
• graft mass the content ratio of the graft portion contained in the modified resin
• Solvents include, for example, alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and mesitylene; esters such as methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; and aliphatic hydrocarbons such as hexane, heptane, cyclohexane, and methylcyclohex
• the adhesive composition contains a solvent and is a solution or dispersion (resin varnish) in which each component is dissolved or dispersed in the solvent, coating on the substrate film and formation of the adhesive layer can be smoothly performed, and an adhesive layer of the desired thickness can be easily obtained.
• a test piece was obtained by cutting the substrate 3 into a 20 mm square. Next, the test piece was floated in a solder bath at 288°C for 10 seconds under certain conditions (temperature 23°C, substrate 2 side up) to check the foaming state of the test piece. When no foaming was observed in the test piece for 10 seconds or more, the solder heat resistance was deemed good and marked as "A”. When foaming was observed in the test piece for less than 10 seconds, the solder heat resistance was deemed poor and marked as "C”.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Laminated Bodies (AREA)

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Citations (3)

• 2023
  • 2023-12-20 JP JP2024567688A patent/JPWO2024143120A1/ja active Pending
  • 2023-12-20 WO PCT/JP2023/045750 patent/WO2024143120A1/ja not_active Ceased
  • 2023-12-27 TW TW112151009A patent/TW202438627A/zh unknown

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