adhesive resin composition

Abstract

To provide an adhesive resin composition having good pot-life property since a polyester resin alone can be cured without a curing agent.SOLUTION: An adhesive resin composition includes a polyester resin (A), and satisfies the following requirements (i)-(v). (i) The acid value of the polyester resin (A) is 100 eq / ton or higher. (ii) The content of a curing agent in the adhesive resin composition is less than 1 pts.mass to 100 pts.mass of a solid content of the polyester resin (A). (iii) A diol (a) having two primary hydroxyl groups and no alicyclic structure, and further any or both of a diol (b) having an alicyclic structure, and a diol (c) having one primary hydroxyl group, one secondary hydroxyl group and no alicyclic structure are included as polyol constituents constituting the polyester resin (A). (iv) The polyester resin (A) has a branch structure. (v) The glass transition temperature of the polyester resin (A) is 5-50°C.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive resin composition, a laminate or adhesive sheet having an adhesive layer made of the adhesive resin composition, a printed wiring board or packaging material containing the laminate as a component, and a laminate film for decorating three-dimensional molded products or a film for laminating metal cans containing the adhesive sheet as a component. [Background technology]

[0002] In recent years, adhesives have been used in a variety of fields, but the diversification of their uses has led to a demand for even higher performance adhesives than those used traditionally, such as superior adhesion to substrates such as various plastic films, metals, and glass epoxy, as well as heat resistance. For example, adhesives for circuit boards, including flexible printed circuit boards (FPCs), require adhesion, processability, electrical properties, and shelf life. Traditionally, adhesives used for this purpose include epoxy / acrylbutadiene adhesives and epoxy / polyvinyl butyral adhesives.

[0003] In particular, in recent years, there has been a demand for adhesives with higher solder heat resistance in response to the shift to lead-free solder and the environment in which FPCs are used. Furthermore, there is a strong demand for solder heat resistance due to the increasing density of wiring, the multi-layering of FPC wiring boards, and workability. To address these issues, a resin composition for adhesives, primarily composed of polyester polyurethane and epoxy resin, has been disclosed (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-205370 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] However, the composition described in Patent Document 1 was not fully satisfactory in terms of lead-free solder heat resistance, and furthermore, the pot life after blending of the curing agent, which is important during use, was insufficient.

[0006] An object of the present invention is to provide an adhesive resin composition that can be cured by itself using a polyester resin without substantially containing a curing agent, and that has a good pot life, excellent solder heat resistance, and excellent adhesion to various substrates. [Means for solving the problem]

[0007]

[0006] As a result of extensive research aimed at solving the above problems, the present inventors have found that an adhesive resin composition containing a polyester resin having a predetermined acid value and a specific structure can be cured by the polyester resin alone, substantially without the use of a curing agent. Furthermore, the present inventors have discovered that by specifying the resin composition and controlling the amount of catalyst, an adhesive resin composition can be obtained that has an excellent balance of curability and adhesion to various substrates, does not generate harmful outgassing, has high solder heat resistance that is compatible with lead-free solder, and has significantly improved pot life, and have thereby completed the present invention.

[0008] That is, the present invention comprises the following configuration. [1] An adhesive resin composition comprising a polyester resin (A) and satisfying the following requirements (i) to (iii): (i) The acid value of the polyester resin (A) is 100 eq / ton or more. (ii) The adhesive resin composition is substantially free of a curing agent. (iii) The polyol component constituting the polyester resin (A) includes a diol (a) having two primary hydroxyl groups and no alicyclic structure, and further includes either or both of a diol (b) having an alicyclic structure and a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure. [2] The adhesive resin composition according to [1], wherein the polyester resin (A) has a branched structure. [3] The adhesive resin composition according to [1] or [2], wherein the polyol component constituting the polyester resin (A) contains 20 to 80 mol % of a diol (a) having two primary hydroxyl groups and no alicyclic structure, and further contains 5 to 50 mol % of a diol (b) having an alicyclic structure, or 5 to 75 mol % of a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure. [4] The adhesive resin composition according to [1] or [2], wherein the polycarboxylic acid component constituting the polyester resin (A) contains a polycarboxylic acid having a benzene skeleton, and further contains at least one selected from the group consisting of an aliphatic polycarboxylic acid, an alicyclic polycarboxylic acid, and a polycarboxylic acid having a naphthalene skeleton. [5] The adhesive resin composition according to [1] or [2], wherein the polyester resin (A) contains an unsaturated dicarboxylic acid (d) as a constituent unit. [6] The adhesive resin composition according to [1] or [2], further comprising one or more catalysts (B). [7] The adhesive resin composition according to [1] or [2], wherein the polyester resin (A) has a tetrahydrofuran insoluble content of less than 10 mass% when the polyester resin (A) is heat-treated at 120°C for 15 minutes. [8] A laminate having an adhesive layer made of the adhesive resin composition according to [1] or [2]. [9] An adhesive sheet having an adhesive layer made of the adhesive resin composition according to [1] or [2].

[10] A printed wiring board comprising the laminate according to [8] as a component.

[11] A packaging material comprising the laminate according to [8] as a component.

[12] A laminated film for decorating three-dimensional molded products, comprising the adhesive sheet according to [9] as a component.

[13] A film for laminating metal cans, comprising the adhesive sheet according to [9] as a component. [Effects of the Invention]

[0009] According to the present invention, an adhesive resin composition can be provided which is substantially free of a curing agent and therefore has an excellent pot life, high solder heat resistance, and excellent adhesion to various substrates. DETAILED DESCRIPTION OF THE INVENTION

[0010] The adhesive resin composition of the present invention is characterized by containing a polyester resin (A) and satisfying the following requirements (i) to (iii): (i) The acid value of the polyester resin (A) is 100 eq / ton or more. (ii) The adhesive resin composition is substantially free of a curing agent. (iii) The polyol component constituting the polyester resin (A) includes a diol (a) having two primary hydroxyl groups and no alicyclic structure, and further includes either or both of a diol (b) having an alicyclic structure and a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure.

[0011] <Requirement (i)> Requirement (i) stipulates that the acid value of the polyester resin (A) be 100 eq / ton or more. It is preferably 200 eq / ton or more, more preferably 250 eq / ton or more, and even more preferably 300 eq / ton or more. By having an acid value equal to or greater than the above-mentioned lower limit, sufficient carboxyl groups serving as crosslinking points can be secured, resulting in better curability. Furthermore, when the acid value is equal to or greater than the above-mentioned lower limit, the curing reaction tends to proceed more predominantly than the thermal decomposition reaction when heated to 200°C, improving adhesion and solder heat resistance. Furthermore, having an acid value equal to or greater than the above-mentioned lower limit facilitates aqueous dispersion. There is no particular upper limit for the acid value, but an acid value of 1200 eq / ton or less is preferred in order to reduce the amount of unreacted acid components and oligomers during the acid addition reaction.

[0012] The acid value of the polyester resin (A) can be imparted by any method, such as a method of subjecting a polycarboxylic acid anhydride to an addition reaction in the later stage of polycondensation, or a method of increasing the acid value of a prepolymer (oligomer) and then subjecting it to polycondensation to obtain a polyester resin having an acid value. The former addition reaction method is preferred because of its ease of operation and the ease of obtaining the target acid value.

[0013] Among the compounds having a polycarboxylic acid anhydride group in the molecule for imparting an acid value to the polyester resin (A), examples of carboxylic acid monoanhydrides include phthalic anhydride, succinic anhydride, maleic anhydride, trimellitic anhydride, itaconic anhydride, citraconic anhydride, 5-(2,5-dioxotetrahydrofurfuryl)-3-cyclohexene-1,2-dicarboxylic acid monoanhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, etc., and one or more of these can be selected and used. Among these, trimellitic anhydride is preferred from the standpoints of versatility and economy.

[0014] Among the compounds having a polycarboxylic acid anhydride group in the molecule for imparting an acid value to the polyester resin (A), examples of the carboxylic acid polyanhydride include pyromellitic anhydride, 1,2,3,4-butanetetracarboxylic acid dianhydride, 1,2,3,4-pentanetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, cyclopentanetetracarboxylic acid dianhydride, 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic acid dianhydride, and 1,2,5,6-naphthalenetetracarboxylic acid dianhydride. Examples of suitable dianhydrides include ethylene tetracarboxylic dianhydride, ethylene glycol bistrimellitate dianhydride, 2,2',3,3'-diphenyltetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, ethylene tetracarboxylic dianhydride, 4,4'-oxydiphthalic dianhydride, and 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride. One or more of these can be selected and used. Among these, ethylene glycol bistrimellitate dianhydride is preferred.

[0015] The compound having a polycarboxylic acid anhydride group in the molecule for imparting the acid value may be a carboxylic acid monoanhydride or a carboxylic acid polyanhydride, which may be used alone or in combination.

[0016] <Requirement (ii)> Requirement (ii) stipulates that the adhesive resin composition of the present invention is substantially free of a curing agent. This "substantially free of a curing agent" means that the curing agent content is less than 1 part by mass (solid content equivalent) per 100 parts by mass (solid content equivalent) of polyester resin (A). The adhesive resin composition of the present invention self-crosslinks upon heating, and therefore can be cured even if it is substantially free of a curing agent. Here, the curing agent refers to a known curing agent that reacts with the polyester resin (A) of the present invention to form a crosslinked structure, and the form of the crosslinked structure can be, for example, a reaction in which unsaturated double bonds in the polyester resin are reacted by radical addition reaction, cation addition reaction, anion addition reaction, etc. to form an intermolecular carbon-carbon bond, or the formation of an intermolecular bond by condensation reaction with polycarboxylic acid groups or polyhydric alcohol groups in the polyester resin, polyaddition reaction, transesterification reaction, etc. Examples of curing agents include phenolic resins, amino resins, isocyanate compounds, epoxy compounds, β-hydroxylamide compounds, unsaturated bond-containing resins, etc.

[0017] In the adhesive resin composition of the present invention, the content of the curing agent is less than 1 part by mass per 100 parts by mass of the polyester resin (A) (solid content). Less than 0.5 parts by mass is more preferable, less than 0.1 parts by mass is even more preferable, and it is most preferable that no curing agent is contained. If the content of the curing agent is higher than the above range, the pot life is poor. Furthermore, not only is economical, but there is also a risk of reduced adhesion due to a self-condensation reaction between the curing agents.

[0018] <Requirement (iii)> Requirement (iii) stipulates that the polyester resin (A) of the present invention contains, as its polyol components, a diol (a) having two primary hydroxyl groups and no alicyclic structure, and further contains either or both of a diol (b) having an alicyclic structure and a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure. (Hereinafter, each component may be referred to as component (a), component (b), or component (c), respectively.) Component (a) easily forms ester bonds, while components (b) and (c) have ester bonds that are more easily cleaved than those of component (a). Therefore, the presence of component (a) together with components (b) and (c) promotes rearrangement and recombination of ester bonds during heat treatment, resulting in good curability and improved adhesion and solder heat resistance.

[0019] Examples of the diol (a) having two primary hydroxyl groups and no alicyclic structure in the polyester resin (A) include aliphatic glycols such as ethylene glycol, 1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,4-butanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,8-octanediol, 3-methyl-1,6-hexanediol, 4-methyl-1,7-heptanediol, 4-methyl-1,8-octanediol, and 1,9-nonanediol; and polyether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. One or more of these can be selected and used. Among these, it is preferable to use ethylene glycol, 2-methyl-1,3-propanediol, and 1,6-hexanediol.

[0020] In the polyester resin (A), the copolymerization ratio of the diol (a) having two primary hydroxyl groups and no alicyclic structure is preferably 20 to 80 mol % of the total polyol components, more preferably 20 to 60 mol %, and even more preferably 20 to 40 mol %. When it is within the above range, the curability and solder heat resistance are good.

[0021] The polyester resin (A) preferably contains a diol (b) having an alicyclic structure as a polyol component. The presence of the diol (b) having an alicyclic structure facilitates achieving both adhesiveness and solder heat resistance. Examples of the diol (b) having an alicyclic structure that constitutes the polyester resin (A) include 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane glycols, and hydrogenated bisphenols, and one or more of these can be selected and used. Among these, the use of 1,4-cyclohexanedimethanol is preferred from the viewpoints of curability, adhesiveness, and solder heat resistance.

[0022] The copolymerization ratio of the diol (b) having an alicyclic structure constituting the polyester resin (A) is preferably 5 to 50 mol % of the total polyol components, more preferably 10 to 40 mol %, and even more preferably 20 to 30 mol %. When it is within the above range, good adhesiveness is obtained.

[0023] The polyester resin (A) preferably contains, as a polyol component, a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and not having an alicyclic structure. Examples of the diol (c) having one primary hydroxyl group and one secondary hydroxyl group and not having an alicyclic structure in the polyester resin (A) include 1,2-propylene glycol and 1,2-butanediol, and one or more of these can be selected and used. Among these, the use of 1,2-propylene glycol is preferred.

[0024] The copolymerization ratio of the diol (c) having one primary hydroxyl group and one secondary hydroxyl group but no alicyclic structure in the polyester resin (A) is preferably 5 to 75 mol % of the total polyol components, more preferably 10 to 65 mol %, and even more preferably 15 to 50 mol %. When it is within the above range, good curability and solder heat resistance are obtained.

[0025] The polycarboxylic acid component constituting the polyester resin (A) is not particularly limited, and examples thereof include polycarboxylic acids having a benzene skeleton, such as terephthalic acid, isophthalic acid, and orthophthalic acid, and polycarboxylic acids having a naphthalene skeleton, such as 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 1,8-naphthalenedicarboxylic acid. These can be used alone or in combination of two or more. Among these, a combination of a polycarboxylic acid having a benzene skeleton and a polycarboxylic acid having a naphthalene skeleton is preferred in terms of achieving both adhesiveness and solder heat resistance. When a polycarboxylic acid having a benzene skeleton and a polycarboxylic acid having a naphthalene skeleton are used in combination, the molar ratio of polycarboxylic acid having a benzene skeleton to polycarboxylic acid having a naphthalene skeleton is preferably 95 / 5 to 70 / 30, more preferably 90 / 10 to 75 / 25. By keeping the ratio within the above range, adhesiveness and solder heat resistance are improved, which is preferable. Furthermore, terephthalic acid is preferred as the polycarboxylic acid having a benzene skeleton, and 2,6-naphthalenedicarboxylic acid is preferred as the polycarboxylic acid having a naphthalene skeleton.

[0026] Other polycarboxylic acid components constituting the polyester resin (A) include aliphatic polycarboxylic acid components and alicyclic polycarboxylic acid components. Examples of aliphatic polycarboxylic acid components include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid. Examples of alicyclic polycarboxylic acid components include 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydroisophthalic acid, and 1,2-cyclohexenedicarboxylic acid. One or more of these can be selected and used. The inclusion of an aliphatic polycarboxylic acid component or an alicyclic polycarboxylic acid component can improve adhesion. Among these, adipic acid and 1,4-cyclohexanedicarboxylic acid are preferred in terms of reactivity and economy.

[0027] When the polyester resin (A) contains an aliphatic dicarboxylic acid component or an alicyclic dicarboxylic acid component as a constituent unit, the copolymerization ratio thereof is preferably 5 to 40 mol % of the total polycarboxylic acid components, and more preferably 15 to 35 mol %. If the ratio is outside the above range, the glass transition temperature of the polyester resin (A) may decrease significantly, and the solder heat resistance may decrease.

[0028] The polycarboxylic acid component constituting the polyester resin (A) preferably contains an unsaturated dicarboxylic acid (d) as a constituent unit. The presence of the unsaturated dicarboxylic acid (d) can improve curability and solder heat resistance by a reaction that generates an intermolecular carbon-carbon bond due to the cleavage of the unsaturated bond during heat treatment. Examples of the unsaturated dicarboxylic acid (d) include fumaric acid, maleic acid, itaconic acid, citraconic acid, 2,5-norbornanedicarboxylic acid, and tetrahydrophthalic acid, as well as their anhydrides. These can be used singly or in combination.

[0029] When the polyester resin (A) has an unsaturated dicarboxylic acid (d) as a constituent unit, the copolymerization ratio of the unsaturated dicarboxylic acid (d) is preferably 5 to 20 mol % of the total polycarboxylic acid components, and more preferably 10 to 15 mol %. By being within this range, both adhesiveness and solder heat resistance can be achieved.

[0030] The polyester resin (A) preferably has a branched structure. Having a branched structure refers to the presence of a branched structure in the polyester main chain. An example of a method for introducing a branched structure into the polyester resin (A) is to copolymerize a trifunctional or higher functional component as part of the polycarboxylic acid component and / or polyol component in the polyester polycondensation reaction. Examples of trifunctional or higher functional polycarboxylic acid components include trimellitic acid, pyromellitic acid, and benzophenone tetracarboxylic acid. Examples of trifunctional or higher functional polyols include glycerin, trimethylolethane, trimethylolpropane, mannitol, sorbitol, pentaerythritol, and α-methyl glucoside. The branched structure of the polyester resin (A) increases the crosslink density when ester bonds rearrange and recombine during heat treatment, thereby increasing the THF-insoluble content and improving curability, solder heat resistance, and adhesion.

[0031] The copolymerization ratio of the tri- or higher functional polycarboxylic acid component, when the total polycarboxylic acid components are taken as 100 mol%, is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, and even more preferably 1 mol% or more. It is also preferably 7 mol% or less, more preferably 6 mol% or less, even more preferably 5 mol% or less, and particularly preferably 4 mol% or less. The copolymerization ratio of the tri- or higher functional polyol component, when the total polyol components are taken as 100 mol%, is preferably 0.1 mol% or more, more preferably 0.5 mol% or more, and even more preferably 1 mol% or more. It is also preferably 5 mol% or less, more preferably 3 mol% or less, even more preferably 2 mol% or less, and particularly preferably 1 mol% or less. If the polycarboxylic acid component and the polyol component each exceed the above range, the polyester resin may lose flexibility, resulting in reduced adhesiveness or gelation during polyester polymerization.

[0032] The polycarboxylic acid component and polyol component constituting the polyester resin (A) can be derived from biomass resources. Biomass resources include the stored materials obtained by converting solar energy into starch, cellulose, etc. through photosynthesis in plants, the bodies of animals that grow by eating plants, and products made by processing plants or animals. Among these, plant resources are more preferred, including wood, rice straw, rice husks, rice bran, used rice, corn, sugarcane, cassava, sago palm, soybean pulp, corn cob, tapioca dregs, bagasse, vegetable oil cakes, potatoes, buckwheat, soybeans, oils and fats, waste paper, papermaking residues, seafood residues, livestock excrement, sewage sludge, and food waste. Corn, sugarcane, cassava, and sago palm are even more preferred.

[0033] Next, a method for producing the polyester resin (A) will be described. In the esterification / exchange reaction, all monomer components and / or oligomers thereof are heated, melted, and reacted. The esterification / exchange reaction temperature is preferably 180 to 250°C, more preferably 200 to 250°C. The reaction time is preferably 1.5 to 10 hours, more preferably 3 to 6 hours. The reaction time is the time from when the desired reaction temperature is reached until the subsequent polycondensation reaction begins. In the polycondensation reaction, the polyol component is distilled off from the esterified product obtained in the esterification reaction under reduced pressure at a temperature of 220 to 280°C, and the polycondensation reaction is continued until the desired molecular weight is reached. The polycondensation reaction temperature is preferably 220 to 280°C, more preferably 240 to 275°C. The degree of reduced pressure is preferably 130 Pa or less. Insufficient reduced pressure is undesirable because it tends to prolong the polycondensation time. The time required for reducing the pressure from atmospheric pressure to 130 Pa or less is preferably 30 to 180 minutes.

[0034] In the esterification / exchange reaction and polycondensation reaction, polymerization is carried out as necessary using an organic titanate compound such as tetrabutyl titanate, or an organic tin compound such as germanium dioxide, antimony oxide, or tin octoate. From the viewpoint of reactivity, organic titanate compounds are preferred, and from the viewpoint of resin coloration, germanium dioxide is preferred.

[0035] The glass transition temperature of the polyester resin (A) is preferably 5 to 50° C., more preferably 10 to 40° C., from the viewpoint of solder heat resistance and adhesiveness. When the glass transition temperature is within the above range, the solder heat resistance and adhesiveness to the substrate are improved.

[0036] The reduced viscosity of the polyester resin (A) is preferably 0.2 to 0.6 dL / g, more preferably 0.3 to 0.5 dL / g. When the reduced viscosity is equal to or greater than the lower limit, the cohesive force of the resin improves adhesion to substrates. On the other hand, when the reduced viscosity is equal to or less than the upper limit, the melt viscosity and solution viscosity become appropriate, improving workability. In addition, the number of hydroxyl terminal groups can be increased, making it easier to impart a sufficient acid value.

[0037] As described above, the adhesive resin composition of the present invention can be cured even if it does not substantially contain a curing agent because it undergoes self-crosslinking by heat treatment.

[0038] The adhesive resin composition of the present invention preferably has a tetrahydrofuran-insoluble content of 10% by mass or more when heated at 200°C for 1 hour. As described above, the adhesive resin composition of the present invention undergoes self-crosslinking upon heating. The amount of tetrahydrofuran-insoluble content during heat treatment is an indicator of the degree of self-crosslinking due to heating. When the tetrahydrofuran (THF)-insoluble content is 10% by mass or more, an adhesive resin composition and adhesive layer thereof exhibiting sufficient curability and an excellent balance between solder heat resistance and adhesiveness can be obtained. Here, the adhesive layer refers to a layer of the adhesive resin composition of the present invention after applying the adhesive resin composition of the present invention to a substrate and drying it. The THF-insoluble content is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 70% by mass. If it is less than 10% by mass, the curability may be insufficient, and the adhesiveness and solder heat resistance may be reduced. The amount of tetrahydrofuran insoluble matter during heat treatment (the degree of self-crosslinking due to heating) can be controlled by a conventionally known method, for example, by adjusting the type and blending ratio of each component of the polyester resin (A) or by blending a catalyst.

[0039] Here, "the tetrahydrofuran insoluble content when heat-treated at 200°C for 1 hour is 10% by mass or more" means that the THF insoluble content is 10% by mass or more when calculated by the following formula: The adhesive resin composition is applied to a copper foil so that the thickness after drying is 10 μm, and the composition is heated at 200°C for 1 hour to form a sample measuring 10 cm in length and 2.5 cm in width. The mass of the sample before immersion in THF is (X), and the mass of the sample after immersion in THF is (Y). The sample is then immersed in 60 ml of THF at 25°C for 1 hour and dried at 100°C for 10 minutes. THF insoluble content (mass%) = [{(Y)-mass of copper foil} / {(X)-mass of copper foil}]×100

[0040] On the other hand, before heat treatment, it is preferable that the resin contains as little cured product as possible from the viewpoint of handling, such as solvent solubility and resin aggregation. The content of such cured product can be determined using the tetrahydrofuran (THF) insoluble content during heat treatment at low temperatures as an indicator. Specifically, the polyester resin (A) used in the present invention preferably has a THF insoluble content of less than 10% by mass when heat treated at 120°C for 15 minutes. This is more preferably less than 5% by mass, even more preferably less than 1% by mass, and may even be 0% by mass. When the THF insoluble content is less than the above value under heating conditions at a relatively low temperature of about 120°C, the generation of aggregates can be suppressed when dissolved in a solvent or when formed into an aqueous dispersion. Here, "the tetrahydrofuran insoluble content after heat treatment at 120°C for 15 minutes is less than 10% by mass" means that the THF insoluble content is less than 10% by mass when calculated using the following formula: (X) is the mass of a sample obtained by applying a polyester resin to a copper foil so that the thickness after drying is 10 μm, heating it at 120°C for 15 minutes, and cutting it into a size of 10 cm long and 2.5 cm wide. The mass of the sample before immersion in THF is (X), and the mass of the sample after immersion in THF is (Y), which is the mass of the sample after immersion in THF. THF insoluble content (mass%) = [{(Y)-mass of copper foil} / {(X)-mass of copper foil}]×100

[0041] [Catalyst (B)] The adhesive resin composition of the present invention preferably further contains a catalyst (B). The inclusion of catalyst (B) promotes self-crosslinking of the polyester resin (A) during heat treatment, increasing the storage modulus E' and improving curing properties. Examples of catalysts include acid catalysts such as sulfuric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, camphorsulfonic acid, and phosphoric acid, as well as amine-blocked catalysts (partially neutralized by adding an amine), organotin compounds such as dibutyltin dilaurate, titanium compounds such as titanium tetrabutoxide, zinc compounds such as zinc acetate, hafnium compounds such as hafnium chloride-THF complex, and rare earth compounds such as scandium triflate. One or more of these catalysts can be used in combination. Among these, dodecylbenzenesulfonic acid and its neutralized products are preferred in terms of compatibility with the polyester resin (A) and hygiene.

[0042] The blending ratio of the polyester resin (A) to the catalyst (B) in the adhesive resin composition of the present invention is preferably (A) / (B)=100 / 0.01 to 0.5 (parts by mass), more preferably 100 / 0.05 to 0.4 (parts by mass), and most preferably 100 / 0.1 to 0.3 (parts by mass). By keeping the ratio within this range, the THF-insoluble content of the adhesive resin composition after heat treatment at 200°C for 1 hour can be increased.

[0043] In the adhesive resin composition of the present invention, the catalyst (B) may be contained in the polyester resin (A) or may be added later. From the viewpoint of avoiding gelation during polymerization of the polyester resin (A), the catalyst (B) is preferably added after the production of the polyester resin (A).

[0044] A radical polymerization inhibitor (C) may be added to the adhesive resin composition of the present invention. The radical polymerization inhibitor (C) is primarily used to prevent gelation due to unsaturated bond cleavage during polymerization of the polyester resin (A), but may also be added after polymerization to improve the storage stability of the polyester resin (A). Examples of the radical polymerization inhibitor (C) include known antioxidants such as phenol-based antioxidants, phosphorus-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, nitro compound-based antioxidants, and inorganic compound-based antioxidants.

[0045] Examples of phenolic antioxidants include 2,5-di-t-butylhydroquinone, 4,4'-butyldenbis(3-methyl-6-t-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-tris-methyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-t-butyl-4-hydroxyphenyl)isocyanurate, and derivatives thereof.

[0046] Examples of phosphorus-based antioxidants include tri(nonylphenyl)phosphite, triphenyl phosphite, diphenylisodecyl phosphite, trioctadecyl phosphite, tridecyl phosphite, diphenyldecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-t-butylphenylditridecyl phosphite), distearyl-pentaerythritol diphosphite, trilauryl trithiophosphite, and derivatives thereof.

[0047] Examples of the amine antioxidant include phenyl-beta-naphthylamine, phenothiazine, N,N'-diphenyl-p-phenylenediamine, N,N'-di-beta-naphthyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, aldol-alpha-naphthylamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer, and derivatives thereof.

[0048] Examples of sulfur-based antioxidants include thiobis(N-phenyl-beta-naphthylamine), 2-mercaptobenziazole, 2-mercaptobenzimidazole, tetramethylthiuram disulfide, nickel isopropyl xanthate, and the like, or derivatives thereof.

[0049] Examples of nitro compound antioxidants include 1,3,5-trinitrobenzene, p-nitrosodiphenylamine, p-nitrosodimethylaniline, 1-chloro-3-nitrobenzene, o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, p-nitrobenzoic acid, nitrobenzene, 2-nitro-5-cyanothiophene, and derivatives thereof.

[0050] Examples of inorganic compound antioxidants include FeCl3, Fe(CN)3, CuCl2, CoCl3, Co(ClO4)3, Co(NO3)3, and Co2(SO4)3.

[0051] As the radical polymerization inhibitor (C), among the above antioxidants, phenol-based antioxidants and amine-based antioxidants are preferred in terms of thermal stability, and those having a melting point of 120° C. or higher and a molecular weight of 200 or higher are more preferred, and those having a melting point of 170° C. or higher are even more preferred. Specific examples include phenothiazine and 4,4′-butyldenbis(3-methyl-6-t-butylphenol).

[0052] The blending ratio of the polyester resin (A) to the radical polymerization inhibitor (C) in the adhesive resin composition of the present invention is preferably (A) / (C)=100 / 0.001 to 0.5 (parts by mass), more preferably 100 / 0.01 to 0.1 (parts by mass), and most preferably 100 / 0.02 to 0.08 (parts by mass). By keeping the ratio within this range, gelation during the production of the polyester resin (A) can be suppressed.

[0053] The adhesive resin composition of the present invention may further contain other components as needed to meet the required properties. Specific examples of such components include known additives such as flame retardants, tackifiers, silane coupling agents, titanium oxide, and known inorganic fillers such as silica, phosphoric acid and its esters, surface smoothing agents, antifoaming agents, dispersants, and lubricants. Fillers such as silica are particularly preferred because their incorporation improves solder heat resistance. While hydrophobic and hydrophilic silica are commonly known as silica, hydrophobic silica treated with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, or the like is preferred here to impart moisture absorption resistance. When silica is incorporated, its amount is preferably 0.05 to 30 parts by mass per 100 parts by mass of polyester resin (A). By adjusting the amount to be equal to or greater than the lower limit, improved solder heat resistance can be achieved. By adjusting the amount to be equal to or less than the upper limit, poor silica dispersion is avoided, resulting in good solution viscosity and improved workability. Furthermore, adhesion is not reduced.

[0054] The adhesive resin composition of the present invention can be used in a state dissolved in a known organic solvent. Examples of organic solvents include toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, methyl cellosolve, butyl cellosolve, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol monoacetate, methanol, ethanol, butanol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, and Solvesso. One or more of these solvents are selected and used in consideration of solubility, evaporation rate, etc.

[0055] The adhesive resin composition of the present invention can be blended with other resins for the purpose of improving the adhesive layer by imparting flexibility, adhesion, etc. Examples of other resins include amorphous polyesters, crystalline polyesters, ethylene-polymerizable unsaturated carboxylic acid copolymers, and ethylene-polymerizable carboxylic acid copolymer ionomers. Blending at least one resin selected from these may impart flexibility and / or adhesion to the coating film.

[0056] The adhesive resin composition of the present invention can be applied to a substrate and then dried to form an adhesive layer. The substrate is not particularly limited, but examples thereof include resin substrates such as film-like resins, metal substrates such as metal plates and metal foils, and paper.

[0057] Examples of the resin substrate include polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluorine-based resin. A film-like resin (hereinafter also referred to as a substrate film layer) is preferred.

[0058] The metal substrate can be any conventionally known conductive material that can be used for circuit boards. Examples of materials include various metals such as SUS, copper, aluminum, iron, steel, zinc, and nickel, as well as their alloys, plated products, and metals treated with other metals such as zinc or chromium compounds. Metal foil is preferred, and copper foil is more preferred. The thickness of the metal foil is not particularly limited, but is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 10 μm or more. It is also preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. If the thickness is too thin, it may be difficult to obtain sufficient electrical performance of the circuit. On the other hand, if the thickness is too thick, processing efficiency during circuit fabrication may be reduced. Metal foil is usually provided in a roll form. The form of the metal foil used in producing the printed wiring board of the present invention is not particularly limited. When a ribbon-shaped metal foil is used, its length is not particularly limited. Its width is also not particularly limited, but is preferably about 250 to 500 cm.

[0059] Examples of the paper include fine paper, kraft paper, roll paper, glassine paper, etc. Examples of the composite material include glass epoxy, etc.

[0060] In view of adhesive strength and durability with the adhesive resin composition of the present invention, the substrate is preferably a polyester resin, a polyamide resin, a polyimide resin, a polyamideimide resin, a liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, a polyolefin resin, a fluorine-based resin, a SUS steel plate, a copper foil, an aluminum foil, or a glass epoxy.

[0061] The laminate of the present invention is a substrate to which an adhesive resin composition is laminated (a two-layer laminate of substrate / adhesive layer), or a substrate is further attached (a three-layer laminate of substrate / adhesive layer / substrate).The laminate of the present invention can be obtained by applying the adhesive resin composition of the present invention to various substrates according to a conventional method, drying the composition, and then laminating another substrate on the composition.

[0062] The adhesive sheet of the present invention is obtained by laminating the laminate and a release substrate via an adhesive resin composition. Specific configurations include laminate / adhesive layer / release substrate, or release substrate / adhesive layer / laminate / adhesive layer / release substrate. By laminating the release substrate, it functions as a protective layer for the substrate. Furthermore, by using a release substrate, the release substrate can be released from the adhesive sheet and the adhesive layer can be transferred to another substrate.

[0063] The adhesive sheet of the present invention can be obtained by applying the adhesive resin composition of the present invention to various laminates and drying them according to conventional methods. Furthermore, by attaching a release substrate to the adhesive layer after drying, the adhesive can be wound up without causing offset onto the substrate, resulting in excellent operability, and the adhesive layer is protected, resulting in excellent storage stability and ease of use. Furthermore, after application to a release substrate and drying, the adhesive layer itself can be transferred to another substrate by attaching another release substrate as needed.

[0064] The release substrate is not particularly limited, but examples include paper such as fine paper, kraft paper, roll paper, and glassine paper, with coating layers of clay, polyethylene, polypropylene, or other filler on both sides, and then a silicone-based, fluorine-based, or alkyd-based release agent coated on each of these coating layers. Other examples include various olefin films such as polyethylene, polypropylene, ethylene-α-olefin copolymer, and propylene-α-olefin copolymer alone, and films such as polyethylene terephthalate coated with the above-mentioned release agent. Due to factors such as the release force between the release substrate and the adhesive layer and the adverse effect of silicone on electrical properties, it is preferable to use a polypropylene-sealed film on both sides of fine paper and then apply an alkyd-based release agent thereon, or an alkyd-based release agent on polyethylene terephthalate.

[0065] In the present invention, the method for coating the adhesive resin composition on a substrate is not particularly limited, but examples include a comma coater and a reverse roll coater. Alternatively, if necessary, an adhesive layer can be formed directly or by transfer onto rolled copper foil or polyimide film, which are components of printed wiring boards. The curing conditions for the adhesive resin composition are typically in the range of about 150 to 260°C for about 1 minute to 3 hours, and more preferably in the range of about 180 to 210°C for about 30 minutes to 2 hours. The thickness of the adhesive layer after drying can be adjusted as needed, but is preferably in the range of 5 to 200 μm. An adhesive film thickness of less than 5 μm results in insufficient adhesive strength. A thickness of 200 μm or more results in insufficient drying, resulting in a large amount of residual solvent, which can cause blisters during pressing in the production of printed wiring boards. The drying conditions are not particularly limited, but a residual solvent content of 1% by mass or less after drying is preferred. A content exceeding 1% by mass can result in the residual solvent foaming during pressing of the printed wiring board, causing blisters.

[0066] The printed wiring board of the present invention includes, as a component, a laminate formed from a metal foil that forms a conductor circuit and a resin substrate. The printed wiring board is manufactured by a conventionally known method, such as a subtractive method, using a metal-clad laminate. The term "printed wiring board" collectively refers to so-called flexible circuit boards (FPCs), flat cables, circuit boards for tape automated bonding (TAB), etc., in which a conductor circuit formed from metal foil is partially or completely covered with a cover film, screen printing ink, etc., as necessary.

[0067] The printed wiring board of the present invention can have any laminated structure that can be used as a printed wiring board. For example, it can be a printed wiring board consisting of four layers: a base film layer, a metal foil layer, an adhesive layer, and a cover film layer. Alternatively, it can be a printed wiring board consisting of five layers: a base film layer, an adhesive layer, a metal foil layer, an adhesive layer, and a cover film layer.

[0068] Furthermore, if necessary, two or more of the above printed wiring boards may be stacked.

[0069] The adhesive resin composition of the present invention can be suitably used in each adhesive layer of a printed wiring board. In particular, when the adhesive resin composition of the present invention is used as an adhesive, it has high adhesion not only to conventional polyimide, polyester film, and copper foil that constitute printed wiring boards, but also to low-polarity resin substrates such as LCP (liquid crystal polymer), and has excellent solder heat resistance. Therefore, it is suitable as an adhesive composition for use in coverlay films, laminates, resin-coated copper foils, and bonding sheets.

[0070] The substrate film of the printed wiring board of the present invention can be any resin film that has conventionally been used as a substrate for printed wiring boards, including polyester resin, polyamide resin, polyimide resin, polyamideimide resin, liquid crystal polymer, polyphenylene sulfide, syndiotactic polystyrene, polyolefin resin, and fluorine-based resin.

[0071] The cover film may be any insulating film conventionally known for use in printed wiring boards. For example, films made from various polymers such as polyimide, polyester, polyphenylene sulfide, polyether sulfone, polyether ether ketone, aramid, polycarbonate, polyarylate, and polyamide-imide resins may be used. Polyimide films are more preferred.

[0072] The printed wiring board of the present invention can be manufactured by any conventionally known process, except for using the materials for each layer described above.

[0073] In a preferred embodiment, a semi-finished product is produced in which an adhesive layer is laminated on a cover film layer (hereinafter referred to as a "cover film-side semi-finished product"). On the other hand, a semi-finished product is produced in which a metal foil layer is laminated on a base film layer to form a desired circuit pattern (hereinafter referred to as a "base film-side two-layer semi-finished product"), or a semi-finished product is produced in which an adhesive layer is laminated on a base film layer and a metal foil layer is laminated on top of it to form a desired circuit pattern (hereinafter referred to as a "base film-side three-layer semi-finished product"). Hereinafter, the base film-side two-layer semi-finished product and the base film-side three-layer semi-finished product are collectively referred to as a "base film-side semi-finished product"). By bonding the cover film-side semi-finished product thus obtained and the base film-side semi-finished product together, a four-layer or five-layer printed wiring board can be obtained.

[0074] The substrate film semi-finished product can be obtained, for example, by a manufacturing method including: (A) a step of applying a solution of a resin that will become the substrate film to the metal foil and initially drying the coating; and (B) a step of heat-treating and drying the laminate of the metal foil and the initially dried coating obtained in (A) (hereinafter referred to as the "heat-treatment and desolvation step").

[0075] The circuit can be formed on the metal foil layer by a conventionally known method. Either an additive method or a subtractive method may be used. The subtractive method is preferred.

[0076] The obtained semi-finished product on the base film side may be used as it is for bonding to the semi-finished product on the cover film side, or may be used for bonding to the semi-finished product on the cover film side after a release film has been attached and stored.

[0077] The cover film semi-finished product is produced, for example, by applying an adhesive to the cover film. If necessary, a crosslinking reaction can be carried out in the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

[0078] The obtained cover film side semi-finished product may be used as it is for bonding to the base film side semi-finished product, or may be used for bonding to the base film side semi-finished product after a release film has been attached and stored.

[0079] The substrate film-side semi-finished product and the cover film-side semi-finished product are stored, for example, in the form of a roll, and then bonded together to produce a printed wiring board. Any bonding method can be used, and for example, they can be bonded together using a press or a roll. They can also be bonded together while heating them using a method such as a hot press or a hot roll device.

[0080] For example, in the case of a reinforcing material that is soft and can be wound up, such as a polyimide film, the reinforcing material semi-finished product is preferably produced by applying an adhesive to the reinforcing material. Furthermore, in the case of a reinforcing plate that is hard and cannot be wound up, such as a metal plate such as SUS or aluminum, or a plate made of glass fiber cured with an epoxy resin, it is preferably produced by transfer coating an adhesive that has been applied in advance to a release substrate. If necessary, a crosslinking reaction can be carried out in the applied adhesive. In a preferred embodiment, the adhesive layer is semi-cured.

[0081] The obtained semi-finished product on the reinforcing material side may be used as it is for bonding to the rear surface of a printed wiring board, or may be used for bonding to a semi-finished product on the base film side after a release film has been attached and stored.

[0082] The base film side semi-finished product, the cover film side semi-finished product, and the reinforcing material side semi-finished product are all laminates for printed wiring boards of the present invention.

[0083] The adhesive resin composition or adhesive sheet of the present invention can be suitably used in various applications, including printed wiring boards, as well as in each adhesive layer of a laminate film for decorating three-dimensional molded products. The laminate film for decorating three-dimensional molded products of the present invention is a film used in the decorative molding of three-dimensional molded products. That is, a decorative film is adhered to various molded products to impart design features and surface protection functions to the molded products. During this process, the film is deformed to conform to the surface of the three-dimensional shape for adhesion. In particular, when the adhesive resin composition of the present invention is used as an adhesive, it exhibits high adhesion to conventional resin substrates, such as soft vinyl chloride film, polycarbonate film, polyester film, and ABS, that constitute laminate films for decorating three-dimensional molded products, and also exhibits excellent sheet life. Therefore, the adhesive resin composition is suitable as an adhesive resin composition for use in laminate films for decorating three-dimensional molded products, such as automotive exterior components (side underskirts, side garnishes, door mirrors, etc.), automotive interior components (instrument panels, door switch panels, etc.), and the housings of home appliances (refrigerators, mobile phones, lighting fixtures, etc.).

[0084] The adhesive resin composition of the present invention and an adhesive sheet using the same can be used as each adhesive layer of a film for laminating metal cans or as a film for laminating metal cans. In particular, when the adhesive resin composition of the present invention is used as an adhesive, it has high adhesion to conventional polyester films that constitute films for laminating metal cans and metal substrates such as tinplate, tin-free steel, and aluminum that constitute metal cans, and also has an excellent pot life. Therefore, it is suitable as each adhesive layer of a film for laminating metal cans or as an adhesive sheet used in a film for laminating metal cans.

[0085] The adhesive resin composition of the present invention and a laminate using the same can be used as a packaging material. In particular, when the adhesive resin composition of the present invention is used as an adhesive, it has high adhesion to plastic films commonly used in packaging materials, such as polyethylene terephthalate, polyethylene naphthalate, vinyl chloride resin, ABS resin, acrylic resin, and polycarbonate resin, and gas barrier substrates such as aluminum foil, and also has excellent pot life. Therefore, it is suitable as each adhesive layer of a packaging material or a laminate used in a packaging material. [Example]

[0086] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Various properties were evaluated according to the following methods. In the examples, "parts" simply means "parts by mass," and "%" means "% by mass."

[0087] <Measurement of the characteristics of polyester resin (A)> (1) Measurement of resin composition A sample of polyester resin (A) was dissolved in deuterated chloroform and subjected to 1H-NMR analysis using a nuclear magnetic resonance (NMR) device 400-MR manufactured by VARIAN Corp. The molar ratio was determined from the ratio of the integral values.

[0088] (2) Measurement of reduced viscosity (unit: dl / g) A 0.1 g sample of polyester resin (A) was dissolved in 25 cc of a mixed solvent of phenol / tetrachloroethane (mass ratio 6 / 4), and the measurement was carried out at 30°C.

[0089] (3) Measurement of glass transition temperature (Tg) Measurement was performed using a differential scanning calorimeter (DSC-200, manufactured by SII Corporation). 5 mg of a sample of polyester resin (A) was placed in an aluminum container with a clamped lid, sealed, cooled to -50°C using liquid nitrogen, and then heated to 150°C at a rate of 20°C / min. In the endothermic curve obtained during this process, the glass transition temperature (Tg, unit: °C) was determined as the temperature at the intersection between the baseline before the endothermic peak and the tangent to the endothermic peak.

[0090] (4) Acid value measurement 0.2 g of a sample of polyester resin (A) was dissolved in 20 ml of chloroform and titrated with 0.01 N potassium hydroxide ethanol solution to obtain 10% of the polyester resin. 6 The equivalent weight per gram (eq / ton) was calculated using phenolphthalein as an indicator.

[0091] (5) Measurement of THF insoluble matter The THF-insoluble content after heat treatment at 120°C for 15 minutes was calculated by the following formula: a methyl ethyl ketone solution of polyester resin (A) (solid content 20% by mass) was prepared, applied to copper foil so that the thickness of polyester resin (A) after drying would be 10 μm, and heated at 120°C for 15 minutes to form a sample measuring 10 cm in length and 2.5 cm in width. The mass of the sample before immersion in THF was defined as (X), and the mass of the sample after immersion in THF was defined as (Y). The mass of the sample after immersion in THF was then calculated by the following formula: THF insoluble content (mass%) = [{(Y)-mass of copper foil} / {(X)-mass of copper foil}]×100

[0092] <Synthesis Example (a) of Polyester Resin (A)> 580 parts by weight of dimethyl terephthalate, 10 parts by weight of trimellitic anhydride, 60 parts by weight of fumaric acid, 310 parts by weight of ethylene glycol, 380 parts by weight of 1,2-propylene glycol, and 0.5 parts by weight of tetra-n-butyl titanate (hereinafter sometimes abbreviated as TBT) as a catalyst (0.03 mol% relative to the total polycarboxylic acid components) were charged into a 3 L four-neck flask, and the temperature was gradually raised to 230 °C over 3 hours to carry out a transesterification reaction. Next, 220 parts by weight of adipic acid was added, and the temperature was gradually raised to 240 °C over 1 hour to carry out an esterification reaction. After the reaction, the pressure in the system was gradually reduced, and polymerization was carried out under reduced pressure to 10 mmHg over 1 hour, while the temperature was raised to 245 °C. A post-polymerization was then carried out for 50 minutes under a vacuum of 1 mmHg or less. After reaching the target molecular weight, the mixture was cooled to 210 °C under a nitrogen atmosphere. Next, 20 parts by mass of trimellitic anhydride and 21 parts by mass of ethylene glycol bistrimellitate dianhydride were added, and stirring was continued for 30 minutes at 200 to 230°C under a nitrogen atmosphere. The mixture was removed to obtain a polyester resin (Synthesis Example (a)). The resulting polyester resin had a reduced viscosity of 0.30 dl / g, a glass transition temperature (Tg) of 20°C, and an acid value of 300 eq / ton.

[0093] Synthesis examples (b)~(o) Polyester resins (Synthesis Examples (b) to (o)) having the resin compositions and properties shown in Table 1 were produced by the same direct polymerization method as in Synthesis Example (a), except that the charged compositions were changed.

[0094] [Table 1]

[0095] <Evaluation of the properties of adhesive resin compositions> (1) Measurement of THF insolubles The THF insoluble content after heat treatment at 200°C for 1 hour was calculated by the following formula: the adhesive resin composition was applied to copper foil so that the thickness after drying would be 10 μm, and the sample was heated at 200°C for 1 hour to a size of 10 cm in length and 2.5 cm in width. The mass of the sample before immersion in THF was defined as (X), and the mass of the sample after immersion in THF (Y) was defined as the mass after immersion in THF. THF insoluble content (mass%) = [{(Y)-mass of copper foil} / {(X)-mass of copper foil}]×100

[0096] (2) Peel strength (adhesion to polyimide film or copper foil substrate) The adhesive resin composition described below was applied to a 12.5 μm thick polyimide film (Apical (registered trademark), manufactured by Kaneka Corporation) so that the thickness after drying would be 25 μm, and then dried at 130°C for 10 minutes. The adhesive film (B-stage product) thus obtained was laminated to a 12.5 μm thick polyimide film (PI) or an 18 μm thick rolled copper foil (BHY series, manufactured by JX Nippon Mining Corporation) (Cu). The lamination was carried out at 160°C and 40 kgf / cm with the shiny side of the rolled copper foil in contact with the adhesive layer. 2 The adhesive was then pressed under pressure for 30 seconds to bond the film. The film was then cured by heat treatment at 200°C for 1 hour to obtain a sample for peel strength evaluation. The peel strength was measured by a 90° peel test at 25°C, with the film pulled at a tensile speed of 50 mm / min. This test indicates the adhesive strength at room temperature. <Evaluation criteria> ◎:0.8N / mm or more ○: 0.6N / mm or more and less than 8.0N / mm △: 0.4N / mm or more and less than 0.6N / mm ×: Less than 0.4N / mm

[0097] (3) Peel strength (adhesion to polyester substrate, polycarbonate substrate, or aluminum vapor deposition substrate) The adhesive resin composition described below was applied to a 12.5 μm thick polyimide film (Apical (registered trademark), manufactured by Kaneka Corporation) so that the thickness after drying would be 25 μm, and then dried at 200°C for 1 hour. A 25 μm thick polyester film (E5107, manufactured by Toyobo Co., Ltd.) (PET), a 0.125 mm thick polycarbonate film (Panlite sheet, manufactured by Teijin Limited) (PC), or a 30 μm thick aluminum-deposited polyester film (Al, manufactured by Toyobo Co., Ltd.) was laminated to the adhesive layer (B-stage product) thus obtained. The lamination was carried out at 120°C and 40 kgf / cm , with the untreated surface of the polycarbonate film, the corona-treated surface of the polyester film, or the aluminum-deposited surface of the aluminum-deposited polyester film in contact with the adhesive layer. 2 The specimens were pressed and bonded under a pressure of 0.05 mm for 30 minutes to obtain a sample for peel strength evaluation. Peel strength was measured by performing a 90° peel test at 25°C with the polyimide film pulled at a tensile speed of 50 mm / min. This test indicates adhesive strength at room temperature. <Evaluation criteria> ◎:0.8N / mm or more ○: 0.6N / mm or more and less than 8.0N / mm △: 0.4N / mm or more and less than 0.6N / mm ×: Less than 0.4N / mm

[0098] (4) Solder heat resistance Samples were prepared in the same manner as for (2) Peel strength or (3) Peel strength above, and 2.0 cm x 2.0 cm sample pieces were aged at 23°C for 2 days, and then floated in a molten solder bath at 280°C for 10 seconds, and the presence or absence of any changes in appearance such as swelling was confirmed. <Evaluation criteria> ◎: No swelling ○: Some swelling △: Many swellings ×: Swelling and discoloration

[0099] (5) Pot life The pot life refers to the stability of the varnish immediately after blending the adhesive resin composition or after a certain time has passed since blending. When the pot life is good, the increase in viscosity of the varnish is minimal and it can be stored for a long period of time. When the pot life is poor, the viscosity of the varnish increases (thickens), and in severe cases, it gels, making it difficult to apply to a substrate and making it impossible to store for a long period of time. The solution viscosity of the adhesive resin composition prepared above was measured at 25°C using a Brookfield viscometer to determine the initial solution viscosity ηB0. The adhesive resin composition was then stored at 40°C for 7 days, and the solution viscosity ηB was measured at 25°C. The solution viscosity ratio was calculated using the following formula and evaluated as follows: Solution viscosity ratio = solution viscosity ηB / solution viscosity ηB0 <Evaluation criteria> ◎: Solution viscosity ratio is 0.5 or more and less than 1.5 ○: Solution viscosity ratio is 1.5 or more and less than 2.0 △: Solution viscosity ratio is 2.0 or more and less than 3.0 ×: Solution viscosity ratio is 3.0 or more, or viscosity measurement is impossible due to purinization

[0100] <Preparation of adhesive resin composition> 100 parts by mass (solid content) of polyester resin (A) was dissolved in methyl ethyl ketone to a viscosity suitable for application. According to the formulations in Tables 2, 3, and 4, adhesive resin compositions (solid content: approximately 20% by mass) were obtained.

[0101] The resulting adhesive resin compositions were evaluated for THF-insoluble content, adhesion to polyimide film and copper foil substrates, solder heat resistance, and pot life. The evaluation results are shown in Tables 2 and 3. Table 4 also shows the evaluation results for adhesion to polyester substrates, polycarbonate substrates, and aluminum-vapor-deposited substrates, which are suitable for use as laminate films for decorating three-dimensional molded products and as substrates for packaging materials, as well as pot life.

[0102] [Table 2]

[0103] [Table 3]

[0104] [Table 4]

[0105] As is clear from Tables 2 and 4, the adhesive resin composition of the present invention is excellent in all of its adhesion (peel strength), solder heat resistance, and pot life. On the other hand, in Comparative Example 1, the polyester resin did not contain components (b) and (c) as polyol components, so curing was poor and the adhesion (peel strength) and solder heat resistance were inferior. In Comparative Example 2, the polyester resin did not contain component (a) as a polyol component, so curing was poor and the adhesion (peel strength) and solder heat resistance were inferior. In Comparative Examples 3 and 4, the polyester resin had a low acid value, so curing was poor and the adhesion (peel strength) and solder heat resistance were inferior. In Comparative Examples 5 and 6, a curing agent was added, so the pot life was poor. [Industrial Applicability]

[0106] The present invention is an adhesive resin composition and adhesive sheet with excellent adhesion, solder heat resistance, and pot life, as well as a laminate containing the same, which are particularly useful as adhesives for circuit boards such as FPCs. They also have adhesion to polyester substrates, polycarbonate substrates, and aluminum-deposited substrates, and can be used as an adhesive for laminate films for decorating three-dimensional molded products and packaging materials.

Claims

1. An adhesive resin composition comprising a polyester resin (A) and satisfying the following requirements (i) to (v): (i) The acid value of the polyester resin (A) is 100 eq / ton or more. (ii) The content of the curing agent in the adhesive resin composition is less than 1 part by mass, calculated as solid content, per 100 parts by mass of the solid content of the polyester resin (A). (iii) The polyol component constituting the polyester resin (A) includes a diol (a) having two primary hydroxyl groups and no alicyclic structure, and further includes either or both of a diol (b) having an alicyclic structure and a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure. (iv) The polyester resin (A) has a branched structure. (v) The glass transition temperature of the polyester resin (A) is 10 to 50°C.

2. 2. The adhesive resin composition according to claim 1, wherein the polyol component constituting the polyester resin (A) contains 20 to 80 mol % of a diol (a) having two primary hydroxyl groups and no alicyclic structure, and further contains 5 to 50 mol % of a diol (b) having an alicyclic structure, or 5 to 75 mol % of a diol (c) having one primary hydroxyl group and one secondary hydroxyl group and no alicyclic structure.

3. 3. The adhesive resin composition according to claim 1, wherein the polycarboxylic acid component constituting the polyester resin (A) comprises a polycarboxylic acid having a benzene skeleton, and further comprises at least one selected from the group consisting of an aliphatic polycarboxylic acid, an alicyclic polycarboxylic acid, and a polycarboxylic acid having a naphthalene skeleton.

4. 3. The adhesive resin composition according to claim 1, wherein the polyester resin (A) contains an unsaturated dicarboxylic acid (d) as a constituent unit.

5. 3. The adhesive resin composition according to claim 1, wherein the polyester resin (A) has a tetrahydrofuran-insoluble content of less than 10% by mass when the polyester resin (A) is heat-treated at 120°C for 15 minutes.

6. A laminate having an adhesive layer made of the adhesive resin composition according to claim 1 or 2.

7. An adhesive sheet having an adhesive layer comprising the adhesive resin composition according to claim 1 or 2.

8. A printed wiring board comprising the laminate according to claim 6 as a component.

9. A packaging material comprising the laminate according to claim 6 as a component.

10. A laminated film for decorating three-dimensional molded products, comprising the adhesive sheet according to claim 7 as a constituent element.

11. A film for laminating metal cans, comprising the adhesive sheet according to claim 7 as a constituent element.

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