JP5978782B2 - Thermosetting adhesive composition, thermosetting adhesive sheet and reinforced flexible printed wiring board - Google Patents

Description

  The present invention relates to a thermosetting adhesive composition containing an acrylic copolymer, an epoxy resin, and a curing agent for epoxy resin.

  A terminal portion or the like of a flexible printed wiring board made of a polyimide film is lined with a reinforcing base material such as a polyimide film, a glass epoxy plate, or a metal plate to increase its strength. Here, the adhesion between the polyimide film of the flexible printed wiring board and the reinforcing substrate is generally performed by curing a thermosetting adhesive provided therebetween. And as a thermosetting adhesive, in order to obtain good reflow heat resistance, a resin composition in which an acrylic polymer containing both a carboxyl group and an epoxy group contains a resol type phenol resin and an epoxy resin as curing components And a resin composition (Patent Document 2) in which an acrylic polymer containing a carboxyl group and an acrylic polymer containing an epoxy group contain a resole phenolic resin and an epoxy resin as curing components. Are known.

  However, since these thermosetting adhesives contain a large number of functional groups that form a three-dimensional network structure such as carboxyl groups, epoxy groups, and resol type phenolic resins, they have good adhesiveness, but during storage. Since the reaction proceeds, there is a problem that adhesiveness and heat resistance are lowered when stored for several months at room temperature. In addition, even when a flexible printed wiring board is lined with a reinforcing substrate using a thermosetting adhesive immediately after manufacture, the cured thermosetting adhesive is stored during storage of the flexible printed wiring board lined with the reinforcing substrate. There is a problem of moisture-absorbing solder heat resistance that foaming occurs during reflow mounting due to moisture absorption of the agent.

  Therefore, a thermosetting composition used for adhesion and fixation between the flexible printed wiring board and the reinforcing substrate is composed of (A) an acrylic copolymer, (B) an epoxy resin, and (C) a curing agent for epoxy resin. This (A) acrylic copolymer is an acrylic copolymer obtained by copolymerizing (a) an epoxy group-free acrylic monomer, (b) an acrylonitrile monomer, and (c) an epoxy group-containing acrylic monomer. It has been proposed to use a copolymer and to use organic acid dihydrazide particles having a specific particle diameter as a curing agent for epoxy resin (C) (Patent Document 3).

Japanese Patent Laid-Open No. 2007-9058 Japanese Patent Laid-Open No. 2007-9057 JP 2011-79959 A

  The present invention provides stable storage for a thermosetting composition (Patent Document 3) containing the above-mentioned (A) acrylic copolymer, (B) epoxy resin, and (C) a curing agent for epoxy resin. In addition to improving heat resistance and heat-absorbing solder heat resistance, even after storing a flexible printed wiring board backed with a reinforcing substrate in a high-humidity environment such as in summer, foaming does not occur during reflow mounting With the goal.

  The present inventor, in a thermosetting composition containing (A) an acrylic copolymer, (B) an epoxy resin, and (C) a curing agent for epoxy resin, (A) as an acrylic copolymer, When using a partially crosslinked epoxy group with a thiol group-containing compound, the storage stability of the thermosetting composition is improved, and the moisture absorption solder heat resistance of the cured product is significantly improved, The present invention has been completed.

That is, the present invention is a thermosetting adhesive composition containing (A) an acrylic copolymer, (B) an epoxy resin, and (C) a curing agent for an epoxy resin,
(A) Acrylic copolymer is (a) 65-75 mass% of (meth) acrylic acid ester monomer not containing epoxy group, (b) 20-35 mass% of acrylonitrile monomer, (c) epoxy group containing (meth) The epoxy group is partially crosslinked by reacting 3 to 15% by mass of the acrylate monomer and 0.05 to 0.5% by mass of the thiol group-containing compound having 1 to 3 thiol groups in one molecule. And
(C) A thermosetting adhesive composition in which the epoxy resin curing agent is an organic acid dihydrazide having an average particle size of 0.5 to 15 μm is provided.

  The present invention also provides a thermosetting adhesive sheet in which a thermosetting adhesive layer formed from the above-mentioned thermosetting adhesive composition is formed on a base film, and the flexible printed wiring board is a reinforcing substrate. A reinforced flexible printed wiring board lined with a material, wherein the flexible printed wiring board and the reinforcing base material are bonded and fixed with a thermosetting material of the thermosetting adhesive composition described above. provide.

  The thermosetting adhesive composition of the present invention adheres a flexible printed wiring board formed of a polyimide film or the like and a reinforcing substrate such as a polyimide film, a glass epoxy board, or a stainless steel plate with high peel strength. Can do. Moreover, even if it stores for 6 months at normal temperature and humidity 60% RH, it has the outstanding normal temperature storage characteristic that the fall of peeling strength is less than 10%. Therefore, facilities such as refrigeration are not required for storing the thermosetting adhesive composition, and handling and handling properties are improved.

  Furthermore, a flexible printed wiring board, for reinforcement, can be obtained by storing a base material for reinforcement bonded to a flexible printed wiring board with a thermosetting adhesive composition at a temperature of 40 ° C. and a humidity of 90% RH for 4 days. Excellent moisture-absorbing solder heat resistance, in which foaming does not occur when reflow mounting or floating in a solder bath, even when both the substrate and the adhesive layer formed of a thermosetting adhesive composition are absorbed to saturation Have Therefore, even when lead-free solder reflow where the reflow temperature is higher than that of leaded solder reflow is performed under high humidity such as in summer, lead-free solder reflow resistance during mounting is good.

Hereinafter, the present invention will be described in detail.
The thermosetting adhesive composition of the present invention contains (A) an acrylic copolymer, (B) an epoxy resin, and (C) a curing agent for epoxy resin.

  Here, the acrylic copolymer of component (A) is for imparting film-forming properties at the time of film formation, and for imparting flexibility and toughness to the cured product. ) Acrylic acid ester monomer 65-75% by mass, (b) Acrylonitrile monomer 20-35% by mass, (c) Epoxy group-containing (meth) acrylic acid ester monomer 3-15% by mass, and (d) Thiol group in one molecule The epoxy group is partially crosslinked by reacting 0.05 to 0.5% by mass of 1 to 3 thiol group-containing compounds.

  Among the monomers constituting the acrylic copolymer of component (A), the (a) component non-epoxy group-containing (meth) acrylic acid ester monomer is a conventional acrylic thermosetting material applied in the field of electronic components. It can be appropriately selected from those used in adhesives, such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, i-butyl acrylate, n-hexyl acrylate, n-octyl. Acrylate, i-octyl acrylate, 2-ethylhexyl acrylate, i-nonyl acrylate, stearyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, i Octyl methallyl rate, 2-ethylhexyl methallyl rate, i- nonyl methacrylate, n- dodecyl methacrylate, i- dodecyl methacrylate, stearyl methacrylate and the like, may be used in combination of one or more appropriate. Of these, butyl acrylate or ethyl acrylate is preferably used.

  (A) The usage-amount of the (a) epoxy-group-free (meth) acrylic acid ester monomer at the time of preparation of the acrylic copolymer of a component is 65-75 mass%, Preferably it is 65-70 mass%. If the amount is too small, the peel strength decreases, and if the amount is too large, the heat resistance decreases.

  On the other hand, the acrylonitrile monomer of component (b) is used for improving heat resistance.

  The amount of (b) acrylonitrile monomer used in the preparation of the (A) component acrylic copolymer is 20 to 35% by mass, preferably 25 to 30% by mass. If the amount is too small, the heat resistance will decrease, and if it is too large, it will be difficult to dissolve in the solvent, and as will be described later, when producing a thermosetting adhesive sheet by forming a thermosetting adhesive composition on the substrate film, It becomes difficult to apply the curable adhesive composition by diluting it with a solvent.

  In the thermosetting adhesive composition of the present invention, the epoxy group-containing (meth) acrylic acid ester monomer of component (c) is added to the acrylic copolymer of component (A) in addition to the epoxy resin of component (B). The epoxy resin is used to allow the epoxy resin to react with the epoxy resin curing agent (C) to form a three-dimensional crosslinked structure in the cured product of the thermosetting adhesive composition. When a three-dimensional cross-linked structure is formed, the moisture resistance and heat resistance of the cured product are improved. For example, a reinforced flexible printed wiring board with a reinforcing resin sheet lined by fixing with a cured product of a thermosetting adhesive composition Even when a soldering process (for example, a solder reflow process) at 260 ° C. or higher is performed, it is possible to prevent the swollen phenomenon caused by moisture absorption from occurring in the adhesive fixing portion. Such (c) component epoxy group-containing (meth) acrylic acid ester monomer is appropriately selected from those used in conventional acrylic thermosetting adhesives applied in the field of electronic components. Examples thereof include glycidyl acrylate (GA) and glycidyl methacrylate (GMA). Among these, glycidyl methacrylate (GMA) is preferably used from the viewpoint of safety and market availability.

  The amount of the (c) epoxy group-containing (meth) acrylic acid ester monomer used in the preparation of the (A) component acrylic copolymer is 3 to 15% by mass, preferably 5 to 9% by mass. When the amount is too small, the heat resistance is lowered. When the amount is too large, the peel strength tends to be lowered.

  The thiol group-containing compound having 1 to 3 thiol groups in one molecule of component (d) is an epoxy group of (c) an epoxy group-containing (meth) acrylate monomer in the acrylic copolymer of component (A). Is partially cross-linked and used to improve moisture-absorbing solder heat resistance. In the thiol group-containing compound, it is not preferable that the number of thiol groups in one molecule is 4 or more because the room temperature storage property is lowered. This is because when a thiol group-containing compound having 4 or more thiol groups in one molecule is used, the crosslinking of the epoxy group of the (c) epoxy group-containing (meth) acrylate monomer proceeds excessively, and the thermosetting adhesive composition Since the thermosetting adhesive sheet formed from the material becomes too hard, when the heat-resistant adhesive sheet is heated and adhered to the reinforcing base material, the reinforcing base material is insufficiently wetted so that the peel strength is reduced or the reinforcing base material is This is because bubbles remain due to insufficient embeddability.

  (d) Specific examples of the thiol group-containing compound having 1 to 3 thiol groups in one molecule include, for example, 1-butanediol, bismuthiol, 2,4,6, -trimercapto-1,3,5- Triazine and the like can be mentioned, and among them, bismuthiol is preferable.

  The amount of (d) the thiol group-containing compound having 1 to 3 thiol groups in one molecule at the time of preparing the acrylic copolymer (A) is 0.05 to 0.5% by mass, preferably 0. 0.1 to 0.3% by mass. If the amount is too small, the epoxy group of the (meth) epoxy group-containing (meth) acrylic acid ester monomer cannot be sufficiently crosslinked, so that the heat resistance of the hygroscopic solder cannot be improved. Since the crosslinking of the epoxy group of the (meth) acrylic acid ester monomer proceeds excessively, the elastic modulus increases, and the step cannot be embedded during press bonding.

  The acrylic copolymer (A) comprises the above-mentioned (a) epoxy group-free (meth) acrylic acid ester monomer, (b) acrylonitrile monomer, and (c) epoxy group-containing (meth) acrylic acid ester monomer. The epoxy group of the copolymer can be obtained by (c) partial crosslinking with a thiol group-containing compound having 1 to 3 thiol groups in one molecule and an amine catalyst. In this case, the degree of partial crosslinking of the epoxy group depends on the amount of the thiol group-containing compound added, and is preferably 1 to 15% of the epoxy group contained in the acrylic copolymer of the component (A).

(A) component acrylic copolymer is not have an epoxy group remaining by partial crosslinking of the above, the functional groups other than epoxy groups, for example, -COOH, -OH, as much as possible -NH _2, etc. Those are preferred.

  The acrylic copolymer of the component (A) is preferably a weight-average molecular weight because if the molecular weight is too small, the peel strength and heat resistance are lowered, and if it is too large, the solution viscosity tends to increase and the applicability deteriorates. 500,000 to 700,000, more preferably 550000 to 650000.

  On the other hand, the epoxy resin of component (B) is used to cure the thermosetting adhesive composition by forming a three-dimensional network structure by heating at a predetermined temperature, and the cured product has good heat resistance and adhesiveness. Is done.

  The component (B) epoxy resin can be appropriately selected from liquid or solid epoxy resins used in conventional epoxy resin-based thermosetting adhesives applied in the field of electronic components. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, hydrogenated bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, polyalkylene polyol (such as neopentyl glycol) Polyglycidyl ether, tetraglycidyl diaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, tetraglycidyl-m-xylenediamine, diglycidyl phthalate, diglycidyl Xahydrophthalate, diglycidyltetrahydrophthalate, vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl (3,4-epoxycyclohexane) carboxylate, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate One or more of these can be used in appropriate combination.

  The amount of the epoxy resin used as the component (B) in the thermosetting adhesive composition of the present invention is too small, the heat resistance is lowered. Preferably it is 5-30 mass parts with respect to 100 mass parts of a system copolymer, More preferably, it is 10-20 mass parts.

  The (C) component epoxy resin curing agent comprises (c) an epoxy group-derived (meth) acrylic acid ester monomer derived from the (A) component acrylic copolymer, and (B) the component (B) component. It is contained as a curing agent for the epoxy group of the epoxy resin. In the present invention, an organic acid dihydrazide is used as the curing agent. Since the organic acid dihydrazide is solid at room temperature, the room temperature storage characteristics of the thermosetting adhesive composition can be improved by using it as a curing agent for the thermosetting adhesive composition.

  The organic acid dihydrazide as component (C) can be appropriately selected from organic acid dihydrazides conventionally used as curing agents for epoxy resins, such as oxalic acid dihydrazide, malonic acid dihydrazide, and succinic acid. Acid dihydrazide, iminodiacetic acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecanedihydrazide, hexadecanedihydrazide, maleic acid dihydrazide dihydrazide dihydrazide Acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4'-bisbenzenedihydrazide, 1,4-naphtho Acid dihydrazide, Amicure VDH, Amicure UDH (trade name, Ajinomoto Co.), citric acid trihydrazide, 7,11-octadecadienoic 1,18 dicarbohydrazide, and the like. These can be used alone or in combination of two or more. Among these, adipic acid dihydrazide or 7,11-octadecadien-1,18-dicarbohydrazide is used because it has a relatively low melting point, excellent balance of curability, and is easily available. preferable.

  Further, as the organic acid dihydrazide as the component (C), particles having an average particle diameter of 0.5 to 15 μm, preferably 1 to 5 μm are used. If the average particle size of the organic acid dihydrazide particles is too small, when the thermosetting adhesive composition is diluted with an organic solvent and applied, the organic acid dihydrazide particles are dissolved in the organic solvent, and the thermosetting adhesive composition There is a concern that the room temperature storage characteristics of the thermoset may be reduced. On the other hand, if the average particle size of the organic acid dihydrazide is too large, the applicability of the thermosetting adhesive composition is reduced, and the acrylic copolymer (A) or the epoxy resin (B) is sufficient. It becomes difficult to mix.

  In the thermosetting adhesive composition of the present invention, if the amount of the organic acid dihydrazide (C) used is too small, unreacted epoxy groups remain and crosslinking is not sufficient, resulting in poor heat resistance and adhesiveness. Too much excess curing agent remains unreacted, and heat resistance and adhesiveness tend to be reduced. Therefore, it is preferable for a total of 100 parts by mass of (A) acrylic copolymer and (B) epoxy resin. Is 4 to 20 parts by mass, more preferably 6 to 15 parts by mass.

  The thermosetting adhesive composition of the present invention includes, in addition to the components described above, a metal deactivator and an antifoaming agent that do not promote the dissolution of the organic acid dihydrazide as necessary within the range not impairing the effects of the present invention. Well-known additives such as a rust inhibitor and a dispersant can be blended.

  The thermosetting adhesive composition of the present invention comprises (A) an acrylic copolymer, (B) an epoxy resin, (C) a curing agent for an epoxy resin, and additives used as necessary according to a conventional method. It can be prepared by mixing uniformly. The form can be a paste, a film, a dispersed liquid, or the like. Among them, from the viewpoint of storage properties and handling properties at the time of use, a base film such as a polyethylene terephthalate film or a polyimide film, or a base film that has been subjected to a release treatment with silicone or the like, if necessary, is used for the present invention. It is preferable to use the thermosetting adhesive composition as an embodiment of a thermosetting adhesive sheet formed by coating the thermosetting adhesive composition to a thickness of 10 to 50 μm.

  This thermosetting adhesive sheet can be produced through a thermosetting adhesive layer forming coating preparation step and a thermosetting adhesive layer forming step as follows.

  First, in the thermosetting adhesive layer forming coating preparation step, the thermosetting adhesive composition of the present invention is charged into an organic solvent such as methyl ethyl ketone and toluene in an amount that provides a viscosity corresponding to the coating method to be prepared. . As a result, (A) the acrylic copolymer and (B) the epoxy resin, which are the constituent components of the thermosetting adhesive composition, were dissolved in the organic solvent, and (C) the organic acid dihydrazide (curing agent for the epoxy resin). ) Is dispersed in an organic solvent to obtain a thermosetting adhesive layer forming coating. In this case, it is preferable that at least 70% by mass of all organic acid dihydrazide particles are dispersed as solid particles in the thermosetting adhesive layer-forming coating material at room temperature. This is for improving the room temperature storage property of the thermosetting adhesive sheet.

  Next, in the thermosetting adhesive layer forming step, the above-mentioned thermosetting adhesive layer forming coating is applied on the base film by a bar coater, a roll coater or the like so that the dry thickness becomes 10 to 50 μm. A thermosetting adhesive layer is formed by drying by the method. Thus, a thermosetting adhesive sheet in which a thermosetting adhesive layer is formed on the base film can be obtained.

  The thermosetting adhesive composition of the present invention can be preferably used in the field of electronic components. That is, the thermosetting adhesive layer (for example, the thermosetting adhesive layer of the above-mentioned thermosetting adhesive sheet) formed from the thermosetting adhesive composition of the present invention is connected to the terminal portion of the flexible printed wiring board and the like. It is interposed between a reinforcing substrate with a thickness of 50 μm to 2 mm, such as polyethylene terephthalate film, polyimide film, glass epoxy plate, stainless steel plate, aluminum plate, etc. for backing, heat-pressed, flexible printed wiring board and reinforcing material By bonding and fixing to the base material, a reinforced flexible printed wiring board excellent in adhesive strength and moisture absorption solder heat resistance can be produced with high productivity.

  Hereinafter, the present invention will be described specifically by way of examples.

Examples 1-3, Comparative Examples 1-3
(1) Production of thermosetting adhesive composition A thermosetting adhesive composition comprising the monomers shown in Table 1 was produced.
In this case, first, (a) an epoxy group-free (meth) acrylic acid ester monomer, (b) an acrylonitrile monomer, and (c) an epoxy group-containing (meth) acrylic acid ester monomer were copolymerized, and the resulting copolymer was obtained. (D) A thiol group-containing compound having 1 to 3 thiol groups in one molecule was reacted with a tertiary amine catalyst to obtain an acrylic copolymer of component (A). Next, the epoxy resin of (B) component and the hardening | curing agent for epoxy resins of (C) component were added and mixed uniformly to this acrylic copolymer, and the thermosetting adhesive composition was manufactured.

(2) Preparation of paint for forming thermosetting adhesive layer A diluent solvent was added to the thermosetting adhesive composition obtained in (1) and mixed uniformly to prepare a paint for forming a thermosetting adhesive layer.

(3) Production of thermosetting adhesive sheet A polyethylene terephthalate film that has been subjected to a release treatment is prepared as a base film, and the thermosetting adhesive layer-forming paint obtained in (2) is applied to the polyethylene terephthalate film. A thermosetting adhesive sheet was prepared by drying in a drying oven at 0 ° C. to form a thermosetting adhesive layer having a thickness of 35 μm.

(4) Evaluation
(4-1) Preparation of test piece The thermosetting adhesive sheet immediately after obtained in (3) is cut into a strip (5 cm × 10 cm), and the thermosetting adhesive layer is formed into a 175 μm-thick polyimide film (175AH, Kaneka). Was temporarily attached with a laminator set to 80 ° C., and then the base film was removed to expose the thermosetting adhesive layer. A 50 μm thick polyimide film (Kapton 200H, DuPont) of the same size is superimposed on the exposed thermosetting adhesive layer from above, and heated and pressurized at 170 ° C. and a pressure of 2.0 MPa for 60 seconds, then 140 The test piece 1 was obtained by holding in an oven at 60 ° C. for 60 minutes.

  In addition, after the thermosetting adhesive layer of the thermosetting adhesive sheet cut into a strip (5 cm × 10 cm) is pressed against a 0.5 mm SUS304 plate or a 1 mm thick glass epoxy plate, the substrate film is temporarily attached. Was removed to expose the thermosetting adhesive layer. A strip-shaped polyimide film (5 cm × 10 cm) having a thickness of 50 μm is superimposed on the exposed thermosetting adhesive layer, heated and pressurized at 170 ° C. and a pressure of 2.0 MPa for 60 seconds, and then heated at 140 ° C. The test pieces 2 and 3 were obtained by holding in an oven for 60 minutes.

(4-2) Peel strength
A 90 ° peel test was performed on the 50 μm-thick polyimide films of test pieces 1 to 3 obtained in (4-1) at a peel rate of 50 mm / min, and the force required for peeling was measured. The results are shown in Table 1. Peel strength is desired to be 10 N / cm practically.

(4-3) Moisture absorption reflow heat resistance
The test piece 1 obtained in (4-1) was left in a humid heat oven at 140 ° C. and 90% RH for 96 hours. The test piece 1 after the wet heat treatment was passed through a reflow furnace set at a top temperature of 260 ° C. and 30 seconds, and the presence or absence of foaming in the test piece 1 was observed. The results are shown in Table 1. In Table 1, “260 ° C. Pass” means that no foaming was observed.

(4-4) Hygroscopic solder float heat resistance
The test piece 1 obtained in (4-1) was floated on the liquid surface of the solder bath set at a predetermined temperature for 1 minute, and the upper limit temperature at which foaming did not occur on the test piece 1 was measured. The results are shown in Table 1. In Table 1, “260 ° C Pass” means that no foaming was observed in the solder bath at 260 ° C, and “230 ° C” or “240 ° C” means the upper limit temperature at which no foaming was observed. To do.

  Even if the temperature of the reflow furnace in the moisture absorption reflow heat resistance test and the temperature of the solder bath in the moisture absorption solder float heat resistance test are the same, the moisture absorption solder float heat resistance test is directly and instantaneously higher in temperature. Become.

(4-5) Room temperature storage
The test piece 1 obtained in (4-1) was stored at 25 ° C. for 6 months (humidity 65% RH), and the peel strength before and after storage was measured. In general, this difference is desired to be less than 30%. However, in the present invention, a more strict evaluation standard is used, and the difference is less than 10%, preferably less than 2 N / cm, and more than 2 N / cm. Was rated as bad.

  From the results of Table 1, the thermosetting adhesive compositions of Examples 1 to 3 have sufficient peel strength with polyimide films, which are formed of any of polyimide, stainless steel, and glass epoxy as a reinforcing base material. Excellent adhesion, and room temperature storage stability is excellent with less than 10% decrease in peel strength after 6 months storage at room temperature, and moisture absorption solder heat resistance is excellent in a rigorous test called moisture absorption solder float heat resistance test. You can see that

  On the other hand, in the thermosetting adhesive composition of Comparative Example 1, since the epoxy copolymer is not contained in the acrylic copolymer of the component (A), the room temperature storage property and the hygroscopic solder heat resistance are inferior. In the thermosetting adhesive composition, the acrylic copolymer of the component (A) contains an epoxy group, but the epoxy group is not crosslinked, so that the heat resistance of the hygroscopic solder is inferior. In the curable adhesive composition, the acrylic copolymer of the component (A) contains an epoxy group, but the epoxy group is crosslinked with a tetrafunctional thiol group-containing compound, so that the storage stability at room temperature may be inferior. Recognize.

  The thermosetting adhesive composition and the thermosetting adhesive sheet of the present invention can satisfactorily bond a resin substrate such as a polyimide film and a reinforcing substrate such as a polyimide film, a stainless steel plate, a glass epoxy plate, and the like. It exhibits excellent room temperature storage characteristics over a long period of months, and also has excellent moisture-absorbing solder heat resistance. Therefore, it is useful as an adhesive in the field of electronic components that frequently use polyimide materials.

Claims (5)

A thermosetting adhesive composition containing (A) an acrylic copolymer, (B) an epoxy resin, and (C) a curing agent for epoxy resin,
(A) Acrylic copolymer is (a) 65-75 mass% of (meth) acrylic acid ester monomer not containing epoxy group, (b) 20-35 mass% of acrylonitrile monomer, (c) epoxy group containing (meth) The epoxy group is partially crosslinked by reacting 3 to 15% by mass of the acrylate monomer and 0.05 to 0.5% by mass of the thiol group-containing compound having 1 to 3 thiol groups in one molecule. And
(C) A thermosetting adhesive composition in which the epoxy resin curing agent is an organic acid dihydrazide having an average particle size of 0.5 to 15 μm.   (A) A partially cross-linked epoxy group in an acrylic copolymer is (a) an epoxy group-free (meth) acrylic acid ester monomer, (b) an acrylonitrile monomer, and (c) an epoxy group-containing (meth) acrylic acid ester. The thermosetting adhesive composition according to claim 1, wherein the epoxy group of the monomer copolymer is crosslinked with (d) a thiol group-containing compound and an amine catalyst. The thermosetting adhesive composition according to claim 1 or 2 , wherein the organic acid dihydrazide is adipic acid dihydrazide or 7,11-octadecadiene-1,18-dicarbohydrazide.   The thermosetting adhesive sheet in which the thermosetting adhesive layer formed from the thermosetting adhesive composition in any one of Claims 1-3 is formed on a base film.   The thermosetting adhesive composition according to any one of claims 1 to 3, wherein the flexible printed wiring board is a reinforced flexible printed wiring board that is backed by a reinforcing substrate. Reinforced flexible printed wiring board that is bonded and fixed with a thermosetting product.