WO2010041644A1

WO2010041644A1 - Polyamideimide resin, adhesive composition using the resin, ink for printed circuit board using the adhesive composition, cover lay film, adhesive sheet and printed circuit board

Info

Publication number: WO2010041644A1
Application number: PCT/JP2009/067379
Authority: WO
Inventors: 忠司犬飼; 武久家根
Original assignee: 東洋紡績株式会社
Priority date: 2008-10-10
Filing date: 2009-10-06
Publication date: 2010-04-15
Also published as: TW201026750A; JPWO2010041644A1

Abstract

Disclosed is an adhesive composition which enables bonding at low temperatures, while having excellent adhesiveness, solder resistance after humidification, and migration resistance characteristics under high temperature, high humidity conditions. The adhesive composition is particularly useful for circuit boards. Also disclosed are an adhesive sheet and a printed circuit board using the adhesive composition or the adhesive sheet. Specifically disclosed is a polyamideimide resin having a logarithmic viscosity of not less than 0.2 dl/g and an acid value of from 400 equivalent weight/10⁶ g to 1000 equivalent weight/10⁶ g, said polyamideimide resin containing a carboxyl group in a side chain.

Description

Polyamideimide resin, adhesive composition using the resin, printed circuit board ink using the adhesive composition, coverlay film, adhesive sheet, and printed circuit board

The present invention relates to a novel polyamideimide resin, an adhesive composition using the same, a heat resistant ink, an adhesive sheet, a coverlay film, a glass cloth impregnated prepreg, and a printed circuit board using these. In particular, the present invention relates to a heat-resistant ink and an adhesive composition suitable for a printed circuit board excellent in solder heat resistance and high-temperature flexibility after humidification.

Conventionally, as a heat-resistant adhesive, a material mainly composed of a polyimide resin or an epoxy resin has been used, but there are some problems in using these resins.
One of them is the compatibility between heat resistance and low-temperature adhesiveness. Conventionally, polyimide has excellent heat resistance, and therefore requires strong equipment for bonding at high temperatures, and epoxy adhesives that can be bonded at low temperatures have a problem of poor heat resistance.
Several specific methods for achieving both the low-temperature adhesiveness and the heat resistance have been disclosed. For example, there are methods such as using a heat-resistant epoxy resin and a maleimide resin, but these resins are fragile due to their high curing density, and therefore their use is limited. In addition, Patent Document 1 shows that an epoxy resin is blended with a polyetherimide having a specific structure to achieve both low-temperature adhesion and heat resistance. If this is the case, an adhesive temperature of 200 ° C. is necessary, and it cannot be said that the adhesiveness is sufficiently low.
Polyamideimide heat-resistant adhesives have also been proposed. For example, Patent Document 2 and Patent Document 3 disclose polyamideimides copolymerized with acrylonitrile-butadiene and adhesives for semiconductors using the same. And Patent Document 5 propose a polyamideimide copolymerized with dimer acid and an adhesive for semiconductors using the same, all of which have low-temperature adhesion and heat resistance, particularly soldering resistance after humidification, and high temperature. None of the copper foil circuit parts under high humidity satisfy all the migration resistance due to the formation of dendrites.

JP-A 63-99280 JP-A-11-021455 JP 2001-011421 JP-A-11-021454 JP 2001-011420 A

The present invention was devised in view of the current state of the prior art, and its purpose is an adhesive composition containing a polyamide-imide resin that is excellent in low-temperature adhesion, migration resistance and heat resistance, particularly soldering resistance after humidification. Adhesives useful for printed circuit boards, in particular, inks, adhesive sheets, coverlay films, printed circuit board using them, and polyamideimide resins suitable for use in them Is to provide.

The inventor of the present invention has reached the present invention as a result of diligent research in order to achieve such an object. That is, the present invention

(1)
A polyamide-imide resin having a carboxyl group in a side chain having a logarithmic viscosity of 0.2 dl / g or more and an acid value of 400 equivalent / 10 ⁶ g to 1000 equivalent / 10 ⁶ g.
(2)
The polyamideimide resin according to (1), wherein 3 to 30 mol% of the acid component is trimellitic acid when the total acid component of the polyamideimide resin is 100 mol%.
(3)
The polyamideimide resin according to (2), wherein the trimellitic acid is a ring-opened trimellitic acid anhydride by adding water to the trimellitic acid anhydride.
(4)
The polyamideimide resin according to (1), wherein 3 to 30 mol% of the acid component is dimethylolbutanoic acid when the total acid component of the polyamideimide resin is 100 mol%.
(5)
(1) obtained by reacting trimellitic anhydride and / or tetracarboxylic anhydride with a diamine component and / or diisocyanate component to give a prepolymer, and then chain-extending the prepolymer with alkylene glycol. The polyamide-imide resin described.
(6)
The polyamideimide resin according to (5), wherein the alkylene glycol is at least one selected from the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene glycol having a number average molecular weight of 400 to 10,000.
(7)
An adhesive composition characterized in that the polyamideimide resin according to any one of (1) to (6) contains at least one compound selected from the group consisting of a polyfunctional epoxy compound, a polyfunctional isocyanate compound, and a melamine compound. object.
(8)
The adhesive composition as set forth in (7), wherein the organophosphorus compound is contained in an amount of 1% by weight or more and 3% by weight or less with respect to the total solid content of the adhesive composition.
(9)
An ink for printed circuit boards, wherein the adhesive composition according to (7) or (8) contains inorganic and / or organic fine particles and has a thixotropic index of 1.2 or more and 3.0 or less.
(10)
A coverlay film using the adhesive composition according to (7) or (8).
(11)
An adhesive sheet obtained by applying and drying the adhesive composition according to (7) or (8) on a polypropylene film, a release paper, or a release film.
(12)
A printed circuit board using the adhesive composition according to (7) or (8).

ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition excellent in the low temperature adhesiveness and soldering resistance to a metal or a polyimide film, especially the soldering resistance after a humidification process, and the anti-migration property in high temperature, high humidity, and a printed circuit Ink, adhesive sheets, and coverlay films useful for substrates, printed circuit boards using these, and polyamideimide resins suitable for use in these can be easily obtained.

INDUSTRIAL APPLICABILITY The present invention is capable of low-temperature adhesion, and has an adhesive composition excellent in migration resistance and heat resistance, particularly soldering resistance after humidification, and an adhesive sheet, coverlay film, glass cloth impregnated prepreg, and printed circuit formed therefrom. The present invention relates to a printed circuit board using these, and a polyamide-imide resin suitable for use in these.

1. Polyamideimide resin The polyamideimide resin used in the present invention can be produced by a known method such as an acid chloride method or an isocyanate method.

In addition to trimellitic acid and its anhydride and chloride, pyromellitic acid, biphenyltetracarboxylic acid, biphenylsulfonetetracarboxylic acid, benzophenonetetracarboxylic acid, biphenylethertetracarboxylic acid are used as the acid components used in the production of polyamideimide resin. Tetracarboxylic acids such as acids, ethylene glycol bis trimellitate and propylene glycol bis trimellitate and their anhydrides, oxalic acid, adipic acid, malonic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, dicarboxypolybutadiene, dicarboxypoly (Acrylonitrile-butadiene), aliphatic dicarboxylic acids such as dicarboxypoly (styrene-butadiene), 1,4 cyclohexane dicarboxylic acid, 1,3 cyclohexane dicarboxylic acid, 4,4 ′ dicyclo Examples include alicyclic dicarboxylic acids such as hexylmethane dicarboxylic acid and dimer acid, and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, and naphthalenedicarboxylic acid. Trimellitic anhydride is most preferable from the viewpoints of properties, adhesiveness, solubility, and the like, and a part of which is replaced with trimellitic acid, dicarboxypoly (acrylonitrile-butadiene) or dimer acid is more preferable.

Examples of the diamine or diisocyanate used in the production of the polyamideimide resin include aliphatic diamines such as ethylenediamine, propylenediamine, and hexamethylenediamine, and diisocyanates thereof, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, isophoronediamine, 4 Alicyclic diamines such as 4,4'-dicyclohexylmethanediamine and their diisocyanates, m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diamino Aromatic diamines such as diphenylsulfone, benzidine, o-tolidine, 2,4-tolylenediamine, 2,6-tolylenediamine, xylylenediamine, diaminopoly (acrylonitrile-butadiene Among them, 4,4′-diaminodiphenylmethane or 4,4′-diphenylmethane diisocyanate, isophoronediamine or isophorone diisocyanate, and diaminopoly (acrylonitrile-butadiene are preferred because of their heat resistance, adhesiveness, solubility and the like. Etc.) are preferred.

The polyamidoimide resin of the present invention can be copolymerized with a polyhydric alcohol component in addition to the acid component and the diamine or diisocyanate component. Polyhydric alcohol components include ethylene glycol, diethylene glycol, triethylene glycol, dimethylol butanoic acid, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, polyester diol, carbonate diol and other diols and pentaerythritol. Among these, polyester diol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol are preferable in view of adhesiveness and solubility. When a carboxyl group is introduced into the side chain, dimethylolbutanoic acid, polyethylene glycol having a number average molecular weight of 400 to 10,000, polypropylene glycol or polytetramethylene glycol are preferred.

The polyamide-imide resin of the present invention has a high acid value in spite of being a high molecular weight material in order to satisfy all of heat resistance when used for a printed circuit board, in particular, solder resistance after humidification, low-temperature adhesion and migration resistance. It is necessary to be. Specifically, the logarithmic viscosity of the polyamideimide resin, which is a measure of molecular weight, is 0.2 dl / g or more. When the logarithmic viscosity is less than 0.2 dl / g, the strength and elongation when formed into a film are low, so that sufficient adhesive force cannot be obtained. The upper limit is not particularly limited, but when the logarithmic viscosity becomes large, when mixing hardeners, flame retardants, and other additives, compatibility with them decreases or work viscosity decreases due to increased solution viscosity In other words, it may be substantially 1.5 dl / g or less. It is preferably 0.3 to 1.0 dl / g, more preferably 0.3 to 0.5 dl / g.
The logarithmic viscosity can usually be adjusted by adjusting the charging ratio of the acid component and the diamine component (diisocyanate component), the polymerization temperature, the concentration, the addition of a catalyst, etc. The diamine component (diisocyanate component) can be increased or the polymerization temperature and concentration can be adjusted. The logarithmic viscosity can be increased by increasing the viscosity or adding a catalyst.

The acid value of the polyamide-imide resin of the present invention is in the range of 400 equivalent / 10 ⁶ g to 1000 equivalent / 10 ⁶ g, preferably 450 equivalent / 10 ⁶ g to 1000 equivalent / 10 ⁶ g, more preferably 500 equivalents / 10 ⁶ g to 1000 equivalents / 10 ⁶ g. If the acid value exceeds the above upper limit, a carboxyl group may remain even after the adhesive composition is cured with a polyfunctional epoxy compound, polyfunctional isocyanate compound, melamine compound, etc., which will be described later, migration resistance and humidification Post solder resistance decreases. On the other hand, when the acid value is less than the above lower limit, the number of reaction points with the polyfunctional epoxy compound, polyfunctional isocyanate compound, melamine compound, etc. decreases, the curing density decreases, and the solder heat resistance after humidification becomes insufficient.
As shown in the following (1) to (4), by giving a carboxyl group to the side chain of the polyamideimide resin, a polyamideimide resin having an acid value in the above range can be obtained. However, it is not limited to the following method.
(1) When the total acid component of the polyamideimide resin is 100 mol%, the polyamideimide is polymerized so that 3 to 30 mol% of the acid component contains trimellitic acid.
For example, if trimellitic anhydride is used as the acid component, the polymerization is carried out by replacing 3 to 30 mol% of trimellitic anhydride with trimellitic acid. In this case, trimellitic acid and a diisocyanate compound of 0.9 to 1.2 equivalents of the trimellitic acid are reacted in advance at 80 ° C. or lower, and then the remaining raw materials (acid component and diisocyanate component) are added for polymerization. It is preferable to carry out. This is because trimellitic anhydride, trimellitic acid and diisocyanate compound are charged simultaneously from the beginning, and gelation may occur when polymerized at a high temperature. As the trimellitic acid, commercially available trimellitic acid may be used as it is, but before or during polymerization, water corresponding to 3 to 30 mol% of trimellitic anhydride is added to trimellitic acid. By ring-opening the acid anhydride, an equivalent amount of trimellitic acid corresponding to water can be produced and reacted with diisocyanate for use. In this case, it is preferable that trimellitic anhydride and water are reacted in advance at a temperature of 80 ° C. or less, and then a diisocyanate compound is added to polymerize the polyamideimide resin.
When the total acid component of the polyamide-imide resin is 100 mol%, 3-30 mol% of the acid component contains trimellitic acid, so that the side chain of the polyamideimide resin can have a carboxyl group, which is effective. In addition, a reaction with a polyfunctional compound such as a polyfunctional epoxy compound, a polyfunctional isocyanate compound, or a melamine compound is performed, and heat resistance such as humidified solder is improved. If it is less than 3 mol%, the acid value of the polyamide-imide resin is low, and when a polyfunctional compound such as a polyfunctional epoxy compound, polyfunctional isocyanate or melamine compound is added, sufficient crosslinking may not be performed, so heat resistance may be insufficient. If the amount exceeds 30 mol%, the film becomes hard and brittle and adhesion may be reduced, or carboxyl groups may be excessive and migration resistance may be reduced.
(2) When the total acid component of the polyamideimide resin is 100 mol%, the polymerization is carried out so that 3 to 30 mol% of the acid component contains dimethylolbutanoic acid.
For example, 3 to 30 mol% of trimellitic anhydride is replaced with dimethylolbutanoic acid and reacted with diisocyanate. In this case, dimethylol butanoic acid may be added at the same time as the other raw materials to be polymerized, but dimethylol butanoic acid and 0.9 to 1.2 moles of the diisocyanate compound are previously added at 80 ° C. or lower. It is also possible to carry out the polymerization by adding other raw materials after the reaction. When dimethylol butanoic acid is added from the beginning at the same time as other raw materials for polymerization, the polymerization is first performed at 80 ° C. or lower to react with dimethylol butanoic acid and a diisocyanate compound, and then polymerization is performed at a temperature of 100 ° C. or higher. It is preferable.
When the total acid component of the polyamide-imide resin is 100 mol%, 3-30 mol% of the acid component contains dimethylol butanoic acid, so that the side chain of the polyamide-imide resin can have a carboxyl group, which is effective. In particular, a reaction with a polyfunctional compound such as a polyfunctional epoxy compound, a polyfunctional isocyanate compound, or a melamine compound is performed, and heat resistance such as humidified solder is improved. If it is less than 3 mol%, the acid value of the polyamide-imide resin is low, and when a polyfunctional compound such as a polyfunctional epoxy compound, polyfunctional isocyanate or melamine compound is added, sufficient crosslinking may not be performed, so heat resistance may be insufficient. If the amount exceeds 30 mol%, the film becomes hard and brittle and adhesion may be reduced, or carboxyl groups may be excessive and migration resistance may be reduced.
(3) After synthesizing trimellitic anhydride and / or tetracarboxylic acid with a diamine component and / or diisocyanate component to synthesize a prepolymer, alkylene glycol is added to react with the remaining acid anhydride to extend the chain. And introducing a carboxyl group into the side chain.
The molecular weight of the prepolymer is not particularly limited, but the number average molecular weight is preferably 10,000 or less, more preferably 5000 or less. When synthesizing the prepolymer, the ratio of the acid component to the diamine component is preferably increased, and in the case of polyamideimide, it is preferably performed after preferential formation of amide bonds. The prepolymer synthesis is preferably performed at 80 ° C. or lower.
As the alkylene glycol, ethylene glycol, propylene glycol, tetramethylene glycol and oligomers thereof can be used. Among them, polyethylene glycol, polypropylene glycol having a number average molecular weight of 400 to 10,000, preferably 600 to 2000, It is preferable to use one or more alkylene glycols selected from the group consisting of polytetramethylene glycol from the viewpoint of adhesiveness. At this time, the chain can be extended with dimethylolbutanoic acid. Polymerization may be performed by adjusting the amount of alkylene glycol added so that the acid value of the whole polyamideimide resin is 400 equivalents / 10 ⁶ g to 1000 equivalents / 10 ⁶ g.
(4) A method of adjusting the acid value of the polyamideimide as a whole by combining the methods (1), (2), and (3) above may be used.

By the method described above, the polyamideimide resin of the present invention having a carboxyl group in the side chain can be obtained. Since it is expected that the polyamide-imide resin will be gelled if it is usually crosslinked, adding a trifunctional compound such as trimellitic acid during the polymerization is an operation that is not usually performed by those skilled in the art. However, as a result of extensive research on polymerization conditions such as temperature control, the present inventors have previously obtained trimellitic acid and a diisocyanate compound of 0.9 to 1.2 equivalents of the trimellitic acid in advance at 80 ° C. or less. It was found that a polyamideimide resin having a carboxyl group in the side chain can be obtained while the gelation is suppressed by carrying out the polymerization by adding the remaining raw materials (acid component and diisocyanate component) after the reaction. One or more compounds selected from the group consisting of a polyfunctional epoxy compound, a polyfunctional isocyanate compound and a melamine compound are added to the polyamideimide resin of the present invention and allowed to react, thereby causing low temperature adhesion and migration resistance under high temperature and high humidity. An adhesive composition excellent in heat resistance and heat resistance, in particular, solder resistance after humidification is obtained. In particular, it excels in migration resistance under high temperature and high humidity and solder resistance after humidification. By newly finding a polymerization method for introducing a carboxyl group into a side chain of a polyamide-imide resin, the number of cross-linking points of the polyamide-imide resin can be increased. The increase in the number of cross-linking points contributes to the improvement of the adhesion, whereby the moisture resistance can be greatly improved, and it is considered that the migration resistance and the solder resistance after humidification are excellent.

The polyamideimide resin of the present invention is stirred in a polar solvent such as N, N′-dimethylacetamide, N-methyl-2-pyrrolidone, N, N′-dimethylformamide, and γ-butyrolactone while heating to 60 to 200 ° C. Can be manufactured easily. In this case, a catalyst can be used if necessary. As the catalyst, metal salts such as sodium methylate and potassium fluoride, and amines such as triethylamine, triethylenediamine and diazabicycloundecene are used. In addition, a part of the above-mentioned polymerization solvent can be replaced with another relatively inexpensive solvent having a low boiling point. These solvents include alcohols such as methanol, ethanol and butanol, ketones such as acetone, butanone and cyclohexanone, esters such as methyl acetate and ethyl acetate, and hydrocarbons such as toluene and xylene as a whole. About 40% by weight, it is preferable to replace the polymerization solvent with these solvents.
The polymerization solution can be used by dissolving it in a solvent immiscible with the polymerization solution, preferably acetone or water, removing the polymerization solvent, washing, drying and re-dissolving in another solvent. Examples of the solvent used for redissolving include alcohols such as methanol, ethanol and butanol, aromatic hydrocarbons such as toluene and xylene, ethers such as tetrahydrofuran and dioxane, and ketones such as cyclopentanone and cyclohexanone.

2. Adhesive composition The adhesive composition of the present invention has a carboxyl group in a side chain having a logarithmic viscosity of 0.2 dl / g or more and an acid value of 400 equivalent / 10 ⁶ g to 1000 equivalent / 10 ⁶ g. The polyamidoimide resin has one or more compounds selected from the group consisting of polyfunctional epoxy compounds, polyfunctional isocyanate compounds and melamine compounds. In the polyamide-imide resin, one or more compounds selected from the group consisting of polyfunctional epoxy compounds, polyfunctional isocyanate compounds and melamine compounds can be blended, heated, and cured to form a highly crosslinked structure. Excellent adhesion and resistance to humidification and soldering can be expressed.
There is no restriction | limiting in particular as a polyfunctional epoxy compound combined with the polyamide-imide resin of this invention, Bisphenol A diglycidyl ether, a phenol novolak-type epoxy compound, an amine-type epoxy compound, etc. are mentioned. From the viewpoint of compatibility with the polyamide-imide resin and the crosslinking density, a phenol novolac type epoxy compound is particularly preferable.
The polyfunctional isocyanate compound is not limited, and examples include tolylene diisocyanate to trimethylolpropane, isophorone diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate triadduct, and hexamethylene diisocyanate cyclic trimer. From the viewpoints of adhesion and crosslink density, a cyclic trimer of hexamethylene diisocyanate is particularly preferable.
Examples of the melamine compound include trimethylolmelamine methyl ether and butyl ether.
These polyfunctional compounds such as polyfunctional epoxy compounds, polyfunctional isocyanate compounds, and melamine compounds are preferably blended in an amount of 3 to 200 parts by weight, more preferably 10 to 10 parts by weight based on 100 parts by weight of the polyamideimide resin. It mix | blends in 100 weight part. If the blending amount of the polyfunctional compound is less than 3 parts by weight, heat resistance and chemical resistance such as humidified solder may be insufficient, and if it exceeds 200 parts by weight, the film becomes hard and brittle so that the adhesiveness is reduced. There is a case.
In order to design in more detail, the number of epoxy groups and NCO groups of polyfunctional compounds such as polyfunctional epoxy compounds, polyfunctional isocyanate compounds, and melamine compounds / number of carboxyl groups of polyamide-imide resin in the previous stage of the curing reaction = 1 to 50 is preferable, and a range of 3 to 25 is more preferable. Since not all of the compounded epoxy compounds are usually involved in the curing reaction, it is preferable to add an equivalent amount or an excess amount with respect to the carboxyl group of the polyamide-imide resin. If the epoxy group is less than 1 with respect to the carboxyl group, the curing may be insufficient and the soldering resistance and migration resistance after humidification may be insufficient, and if it exceeds 50, the adhesive layer after curing is brittle and the adhesion is poor. There is a tendency to decrease.
The acid value of the polyamide-imide resin after the curing reaction is preferably 100 equivalents / 10 ⁶ g or less, more preferably 30 equivalents / 10 ⁶ g or less.

In addition, for these polyfunctional compounds, for example, in the case of epoxy compounds, polyvalent carboxylic acids and their anhydrides, imidazole compounds, and amine-based catalysts are used as curing aids and catalysts. A metal compound such as dibutyltin dilaurate or a catalyst such as p-toluenesulfonic acid can be used in the case of a melamine compound.

In order to impart flame retardancy when the polyamideimide resin of the present invention and an adhesive composition in which a polyfunctional compound such as a polyfunctional epoxy compound, polyfunctional isocyanate compound, or melamine compound is blended are used as an adhesive or a coating agent An organic or inorganic phosphorus compound can be blended with. There is no particular limitation on the phosphorus compound, and phosphoric acid esters and phosphazenes such as red phosphorus, various inorganic phosphates such as sodium phosphate, magnesium phosphate and calcium phosphate, triethyl phosphate, triphenyl phosphate, tricresyl phosphate, and phosphate ester condensates. Compounds, phosphinic acid derivatives and the like can be mentioned, and phosphazene compounds are particularly preferable from the viewpoint of moisture resistance. A phosphorus compound can be added so that the phosphorus content is 1% by weight or more and 3% by weight or less based on the solid content of the adhesive composition. If it is less than 1 weight, it tends to be difficult to obtain a flame-retardant effect.

The adhesive composition of the present invention includes silicone as a flame retardant other than fillers such as silica and calcium carbonate, inorganic and organic pigments, dyes, antistatic agents, leveling agents, and phosphorus compounds within a range that does not impair the content of the present invention. Compounds, aluminum hydroxide, urea compounds, and resins other than polyamideimide, such as polyester, polyamide, polyimide, polyurethane, and the like can be appropriately blended.

The adhesive composition of the present invention can be used as an adhesive solution in which the adhesive composition is dissolved in a solvent. For example, the adhesive solution is applied to an adherend, dried and then overlapped with the other adherend and bonded by a heating roll or heat press, and if necessary, used as an adhesive by performing a heat curing treatment. Can do.
As the solvent, solvents such as N, N′-dimethylacetamide, N-methyl-2-pyrrolidone, N, N′-dimethylformamide, and γ-butyrolactone used in the polymerization of polyamideimide resin can be used. If a solvent remains in the adhesive layer, it may cause undesired results due to firing at the time of adhesion processing or a decrease in heat resistance itself, so high-boiling polymerization solvents may be alcohols such as methanol, ethanol, butanol, methyl acetate, acetic acid. It is preferable to use those substituted with low boiling point solvents such as esters such as ethyl, aromatic hydrocarbons such as toluene and xylene, and ketones such as ether, acetone, butanone and cyclohexanone. It is preferable to replace the polymerization solvent with these solvents by about 40% by weight as a whole.
The solid content concentration in the adhesive solution can be appropriately set depending on the purpose of use, but is preferably 20 to 60% by weight, more preferably 30 to 50% by weight.

The use of the composition containing the polyamidoimide resin of the present invention and a polyfunctional compound such as a polyfunctional epoxy compound, polyfunctional isocyanate compound, and melamine compound is not particularly limited, but the most useful use is an adhesive for printed circuit boards. Or an insulating ink for circuit protection. Specifically, adhesives for bonding copper foil or aluminum foil to insulating base materials such as polyimide film, polyester film, glass-epoxy sheet, phenolic resin sheet, coverlay film adhesive, coverlay, etc. Examples thereof include insulating ink for protection, an adhesive for reinforcing a part of a circuit board with a reinforcing plate, an adhesive for mounting a semiconductor chip directly on the circuit board, and the like.

3. Insulating ink for printed circuit board When the polyamideimide resin of the present invention is used as an insulating ink for printed circuit board, inorganic particles such as silicon oxide and calcium sulfate and / or various kinds are used in a mixed solution of the polyamideimide resin and the polyfunctional compound. The organic fine particles are preferably mixed and dispersed in the mixed solution of the polyamidoimide resin and the polyfunctional compound in an amount of 0.5 to 10% by weight, more preferably 1 to 5% by weight. A thixo index represented by a viscosity ratio at 20 rpm and 25 ° C. is 1.2 or more and 3.0 or less, preferably a silicone-based or acrylic antifoaming agent or leveling agent is mixed with a polyamide-imide resin solution and the polyfunctional compound. It can be used by blending 0.5 to 5% by weight.

4). Cover lay film The cover lay film of the present invention comprises the adhesive composition of the present invention as an adhesive layer and is composed of two layers of an insulating film layer / adhesive layer, or an insulating film layer / adhesive layer / protective film layer. It consists of three layers. The insulating film is a film having a thickness of 5 to 200 μm made of a plastic film such as polyimide, polyester, polyphenylene sulfide, polyether sulfone, polyether ether ketone, aramid, polycarbonate, polyarylate, and the like. A film may be laminated.
In the method for producing a coverlay film, an adhesive solution obtained by dissolving the adhesive composition of the present invention in a solvent is applied to the above-described insulating film and dried to form an adhesive layer.
In this case, it is preferable that the adhesive layer is appropriately semi-cured, and the residual amount after dissolution of the dried adhesive layer in N-methyl-2-pyrrolidone at 100 ° C. for 2 hours is 2 to 70%, Preferably it is 5 to 50%. For this purpose, the drying temperature is preferably 100 to 170 ° C. and the drying time is 1 to 10 minutes. Further, after drying, if necessary, heat treatment may be performed at 50 to 100 ° C. for 10 to 24 hours. The thickness of the adhesive layer after drying is preferably about 5 to 40 μm. For storage and the like, when a three-layer structure is used, a releasable protective film is further laminated and laminated.

5). The adhesive sheet adhesive sheet refers to a composition having the adhesive composition of the present invention as an adhesive layer and having at least one or more peelable protective films. For example, a two-layer structure of protective film layer / adhesive layer or a three-layer structure of protective film layer / adhesive layer / protective film corresponds to this. The protective film layer here is not particularly limited as long as it can be peeled without impairing the form of the adhesive layer, but examples thereof include polypropylene film, polyester film, silicone, wax-treated polyester film, and paper. In addition, metals, ceramics, and the like can be used, and there is an advantage that new functions such as heat dissipation, electromagnetic shielding, reinforcement, and identification can be added as well as protection for the purpose of surface insulation and environmental resistance.
Adhesive solution is applied to a release substrate such as polypropylene film or polyester film, silicone or wax-treated polyester fill or paper, and dried, preferably in a semi-cured state by the same method as the above coverlay film An agent film or a sheet is sandwiched between two types of adherends, heated and pressed with a heating roll or a heat press, and cured if necessary.
Also in this case, as in the coating method, it is preferable to use a sheet dissolved in a low boiling point solvent in order to obtain a sheet having no residual solvent.

6). Printed circuit board The adhesive composition of the present invention is used as an adhesive layer, and an insulating film and a copper foil are laminated together with the adhesive layer, and the printed circuit board ink and coverlay film of the present invention are used for printed circuit. A substrate can be manufactured. As the copper foil, a rolled copper foil or an electrolytic copper foil conventionally used for printed circuit boards can be used. With an insulating film, what was demonstrated as an insulating film of the coverlay film mentioned above can be used.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.
In addition, the measured value in an Example was measured with the following method.

(1) Acid value of polyamideimide resin To a solution obtained by dissolving 0.4 g of polyamideimide in 20 ml of DMF, add 2 to 3 drops of thymolphthalein test solution and a methanol solution of 1/10 normal sodium methoxide to change the color. Determined by titration.

(2) A solution obtained by dissolving 0.5 g of a logarithmic viscosity dry polymer in 100 ml of NMP was measured at 25 ° C. using an Ubbelohde viscosity tube.

(3) Adhesive strength The samples of the examples were measured for peel strength at a peel angle of 90 degrees with Tensilon manufactured by Toyo Baldwin. In Examples 1 to 10 and Comparative Example 4, the adhesive force between the polyimide film and the electrolytic copper foil (mat surface) was used. In Examples 11 to 20 and Comparative Examples 1 to 3, the polyimide film and the rolled copper foil (shine surface) were used. In Examples 21 to 28, the adhesive force between the polyimide film and the aluminum plate reinforcing plate was measured.

(4) The same sample that was measured for the solder-resistant adhesive strength after humidification was allowed to stand for 48 hours in an atmosphere of 40 ° C. and 80% RH and then floated in a solder bath at 260 ° C. for 30 seconds. Observed. The judgment was as follows.
○: No swelling or peeling.
X: Dandruff or peeling occurred.

(5) Migration resistance Various copper-clad laminates prepared in Examples 1 to 10 and Comparative Example 4 were etched to form a circuit having a line / space of 70/70 μm. Niskan Kogyo CISV) was laminated at 150 ° C. for 2 minutes with a heat press and cured at 150 ° C. for 2 hours. While applying a terminal voltage of 50 V to these, the insulation resistance value was measured after being left in an atmosphere of 85 ° C. and 85% RH for 2 weeks.
On the other hand, in Examples 11 to 20 and Comparative Examples 1 to 3, the line / space becomes 70/70 μm in a copper-clad laminate Viroflex (manufactured by Toyobo) using an 18 μm rolled copper foil with an insulating layer of 20 μm. A circuit is formed, and a cover lay film coated with adhesives using various polyamideimide resin solutions is laminated on the circuit surface, and an atmosphere of 85 ° C. and 85% HR is applied with a voltage of 50 V applied between the terminals of the sample. The change in the insulation resistance value after being left for 2 weeks was measured.
The determination is as follows.
○: Insulation resistance value between lines is 1E + 08Ω or more ×: Insulation resistance value between lines is 1E + 08Ω or less

(6) Number average molecular weight of alkylene glycol The hydroxyl value is measured according to JISK-0070, and is determined by the following calculation.
Mn = 56110 × 2 / hydroxyl value

(7) Phosphorus atom content: (wet decomposition, determination of phosphorus by molybdenum blue colorimetric method)
The sample was weighed in an Erlenmeyer flask in accordance with the phosphorus concentration in the sample, 3 ml of sulfuric acid, 0.5 ml of perchloric acid and 3.5 ml of nitric acid were added, and the mixture was gradually decomposed by heating with an electric heater over a half day. When the solution becomes clear, it is further heated to produce white sulfuric acid smoke, allowed to cool to room temperature, this decomposition solution is transferred to a 50 ml volumetric flask, 5 ml of 2% ammonium molybdate solution and 2 ml of 0.2% hydrazine sulfate solution. Was added, and the contents were mixed well with pure water. After heating and coloring in a boiling water bath for 10 minutes, the solution is cooled to room temperature, degassed with ultrasonic waves, the solution is taken into an absorption cell 10 mm, and a blank test solution is controlled with a spectrophotometer (wavelength 830 nm). Then, the absorbance was measured. The phosphorus content was obtained from the calibration curve prepared previously, and the P concentration in the sample was calculated.

(8) Glass transition temperature Polyamideimide resin solution is applied to a polypropylene film so that the dry film thickness is about 30 μm, dried, and then peeled off from the propylene film. Was measured at a frequency of 110 Hz and obtained from the inflection point of the storage elastic modulus.

[Examples 1 to 10]
[Production of polyamideimide resin A]
Dicarboxypoly (acrylonitrile-butadiene) with 0.87 mol trimellitic anhydride (TMA), 0.1 mol trimellitic acid, and 3500 molecular weight (Ube Industries) in a four-necked flask with a condenser and nitrogen gas inlet CTBN 1300 × 13) 0.03 mol and diphenylmethane-4,4′-diisocyanate (MDI) 1.02 mol were charged with N, N′-dimethylacetamide (DMAc) to a solid content concentration of 40% and stirred. The temperature was raised to 80 ° C. for about 2 hours, and the temperature was further raised to 150 ° C. for about 3 hours. While cooling this solution, toluene was added to adjust the solid content concentration to 30%. This was designated as polyamideimide resin A solution. The obtained polyamideimide resin had a glass transition temperature of 205 ° C., a logarithmic viscosity of 0.35 dl / g, and an acid value of 588 eq / 10 ⁶ g.

[Production of polyamide-imide resin B]
A four-necked flask equipped with a condenser and a nitrogen gas inlet was charged with 0.97 mol of TMA, 0.03 mol of CTBN1300 × 13 and 0.1 mol of water together with DMAc so that the solid content concentration would be 40%. After stirring for 1 hour at ℃ to open a part of TMA, 1.02 mol of MDI was charged with DMAc so that the solid content concentration would be 40%, and the temperature was raised to 80 ℃ while stirring for about 2 hours. The mixture was reacted at 150 ° C. for about 3 hours. While this solution was cooled, toluene was added to adjust the solid content concentration to 30%. This was designated as polyamideimide resin B solution. The obtained polyamideimide resin had a glass transition temperature of 203 ° C., a logarithmic viscosity of 0.36 dl / g, and an acid value of 578 eq / 10 ⁶ g.

[Production of polyamide-imide resin C]
In a four-necked flask equipped with a condenser and a nitrogen gas inlet, 0.82 mol of TMA, 0.1 mol of polytetramethylene glycol (PTG850) having a molecular weight of 850, 0.03 mol of CTBN1300 × 13 and dimethylolbutanoic acid (DMBA) ) 0.05 mol, MDI, and 1.04 mol were charged together with DMAc so that the solid concentration would be 50%. The temperature was raised to 60 ° C. with stirring for 2 hours, and further raised to 120 ° C. for about 5 After reacting for a period of time, it was diluted with toluene so that the solid content concentration became 30% while cooling. This was designated as polyamideimide resin C solution. The obtained polyamideimide resin had a glass transition temperature of 201 ° C., a logarithmic viscosity of 0.43 dl / g, and an acid value of 488 eq / 10 ⁶ g.

[Production of polyamide-imide resin D]
The polyamideimide resin C was produced by the same method except that TMA was changed to 0.72 mol and DMBA was changed to 0.15 mol to obtain a polyamideimide resin D solution. Polyamideimide resin D thus obtained had a glass transition temperature of 185 ° C., a logarithmic viscosity of 0.48 dl / g, and an acid value of 736 eq / 10 ⁶ g.

[Production of polyamide-imide resin E]
Manufactured under the same conditions as in the polyamideimide resin C except that TMA was changed to 0.57 mol and DMBA was changed to 0.3 mol in the manufacture of the polyamideimide resin C, and a polyamideimide resin E solution was obtained. Polyamideimide resin E thus obtained had a glass transition temperature of 177 ° C., a logarithmic viscosity of 0.37 dl / g and an acid value of 976 eq / 10 ⁶ g.

[Polyamideimide resin F]
A reaction vessel equipped with a condenser and a nitrogen inlet was charged with TMA 0.97 mol, CTBN 1300 × 13 0.03 mol, MDI 0.9 mol together with DMAc so that the solid concentration would be 50%, and at 80 ° C. After reacting for 2 hours, 0.1 mol of PTG850 was added so that the solid concentration would be 40%, and the temperature was raised to 150 ° C. and reacted for 3 hours. While cooling, the mixture was diluted with toluene so that the solid content concentration became 30%. This was designated as polyamideimide resin F solution. The obtained polyamideimide resin F had a glass transition temperature of 192 ° C., a logarithmic viscosity of 0.36 dl / g, and an acid value of 824 eq / 10 ⁶ g.

[Polyamideimide resin G]
A polyamideimide resin G solution was obtained under the same conditions as the polyamideimide resin C except that TMA was changed to 0.84 mol and DMBA was changed to 0.03 mol in the production of the polyamideimide resin C. Polyamideimide resin G obtained from this had a glass transition temperature of 205 ° C., a logarithmic viscosity of 0.5 dl / g, and an acid value of 410 eq / 10 ⁶ g.

[Polyamideimide resin H]
Manufactured under the same conditions as the polyamideimide resin D except that MDI was changed to 1.07 mol in the manufacture of the polyamideimide D to obtain a polyamideimide resin H solution. The obtained polyamideimide resin H had a glass transition temperature of 188 ° C., a logarithmic viscosity of 0.95 dl / g, and an acid value of 433 eq / 10 ⁶ g.

<Manufacture of adhesive composition-1>
Polyamideimide resin A, B, C, D, E, F, G, H solution produced above 100g, phenol novolac epoxy compound (Japan Epoxy Epicoat 152) 15g, diaminodiphenylsulfone 1.5g, phosphinic acid 10 g of a derivative (a flame retardant BCA, manufactured by Sanko Co., Ltd.) and 5 g of a phosphazene compound (a flame retardant SPB100L) were blended to obtain adhesive compositions a, b, c, d, e, f, g, and h. The phosphorus content relative to the total solid content of each adhesive composition was 2.7% by weight.
<Manufacture of adhesive composition-2>
10 g of trifunctional isocyanate compound coronate EH (manufactured by Nippon Polyurethane) was blended with 100 g of the polyamideimide resin A and B solutions to obtain adhesive compositions a ′ and b ′.
<Manufacture of copper-clad laminates>
Adhesive composition a, b, c, d, e, f, g, h, a ′, b ′ was applied to a 1/2 oz electrolytic copper foil with a gap of 100 μm, dried at 60 ° C. for 5 minutes, and 130 ° C. for 10 minutes. After that, a polyimide film (Akane NPI 12.5 μm made by Kaneka) was superposed on the adhesive surface and pasted with a roll laminator at 180 ° C., and then left in a 150 ° C. oven for 15 hours while wound on a roll. A tension laminate was obtained. Table 1 shows the measurement results of adhesive strength, solder resistance after humidification, and migration resistance.

[Examples 11 to 20]
<Manufacture of adhesive composition-1>
Polyamideimide resins A, B, C, D, E, F, G, and H produced above are 100 g of phenol novolac epoxy compound (Japan Epoxy Epicoat 152), 1.5 g of diaminodiphenylsulfone, and phosphinic acid. 10 g of a derivative (a flame retardant BCA, manufactured by Sanko Co., Ltd.) and 5 g of a phosphazene compound (a flame retardant SPB100L) were blended to obtain adhesive compositions a, b, c, d, e, f, g, and h.
<Manufacture of adhesive composition-2>
10 g of trifunctional isocyanate compound coronate EH (manufactured by Nippon Polyurethane) was blended with 100 g of the polyamideimide resin A and B solutions to obtain adhesive compositions a ′ and b ′.
<Manufacture of coverlay film>
Adhesive composition a, b, c, d, e, f, g, h, a ′, b ′ was applied to a 12.5 μm polyimide film (Kaneka Apical NPI 12.5 μm) with a gap of 150 μm at 60 ° C. A coverlay film was prepared by drying for 5 minutes at 130 ° C. for 5 minutes. This cover lay film was laminated on the circuit surface of Toyobo copper-clad laminate Viroflex using an insulating layer of 20 μm and 18 μm rolled copper foil, heat-pressed at 150 ° C. for 2 minutes, and heat-treated at 150 ° C. for 2 hours. Of the prepared coverlay films, a, b, c, d, e, f, g, and h satisfy the VTM-0 of UL standard in flame retardancy. Table 1 shows the measurement results of adhesive strength, solder resistance after humidification, and migration resistance.

[Examples 21 to 28]
<Manufacture of adhesive sheet>
The adhesive compositions a, b, c, d, e, f, g, and h are applied to a 50 μm polypropylene film, dried at 60 ° C. for 5 minutes and 130 ° C. for 10 minutes, and then peeled off to give a film thickness of 20 μm. Adhesive sheets a ″, b ″, c ″, d ″, e ″, f ″, g ″, h ″.
Next, the adhesive sheets a ″, b ″, c ″, d ″, e ″, f ″, g ′ are applied to the polyimide film surface of the copper-clad laminate prepared using the adhesive composition b. A reinforcing plate made of 0.3 mm aluminum was overlapped through each of ', h'', and crimped for 2 minutes using a heat press at 150 ° C. Thereafter, heat treatment was performed for 2 hours under pressure at the same temperature. Table 1 shows the measurement results of adhesive strength, solder resistance after humidification, and migration resistance.

[Comparative Example-1]
In the production example of the polyamideimide resin C, the glass transition temperature obtained by producing the polyamideimide resin under the same conditions as in the polyamideimide resin production example C is 208 ° C., except that TMA is 0.85 mol and DMBA is 0.02 mol. Production of the adhesive composition of Example 1 using the polyamide-imide resin I having a logarithmic viscosity of 0.50 dl / g and an acid value of 329 eq / 10 ⁶ g. Coverlay films were prepared and tested as in Examples 11-20. Table 1 shows the measurement results of adhesive strength, solder resistance after humidification, and migration resistance. In addition, phosphorus content with respect to the total solid of an adhesive composition was 2.7 weight%.

[Comparative Example-2]
Manufactured under the same conditions except that TMA is 0.47 mol and DMBA is 0.40 mol in the production example of polyamide-imide resin C, glass transition temperature is 169 ° C., logarithmic viscosity is 0.29 dl / g, acid value is Production of adhesive composition of Example 1 using 1130 eq / 10 ⁶ g of polyamideimide resin J. An adhesive composition j having the same composition as in Example 1 was prepared, and coverlay film was prepared in the same manner as in Examples 11-20. Created and tested. Table 1 shows the measurement results of adhesive strength, solder resistance after humidification, and migration resistance. The phosphorus content relative to the total solid content of the adhesive composition was 2.7% by weight.

[Comparative Example-3]
A polyamide-imide resin K was produced in the same manner as the polyamide-imide resin A except that the amount of MDI charged in the production of the polyamide-imide resin A was 0.95 mol. The logarithmic viscosity of the obtained resin was 0.13 dl / g, and the acid value was 1866 eq / 10 ⁶ g. Since this resin has a low molecular weight and does not form a film, the glass transition temperature could not be measured. Using this polyamideimide resin K, the same adhesive composition k as in Production of the adhesive composition of Example 1 was prepared, and a coverlay film was prepared and tested in the same manner as in Examples 11 to 20. It was. Table 1 shows the measurement results of adhesive strength, solder resistance after humidification, and migration resistance. The phosphorus content relative to the total solid content of the adhesive composition was 2.7% by weight.

[Comparative Example 4]
TMA 0.7 mol, CTBN 1300 × 13 0.03 mol, dimer acid 0.25 mol, and MDI 1.02 mol were charged into the above reaction vessel together with DMAc so that the solid concentration would be 40%, and at 120 ° C. for 2 hours. The mixture was reacted at 150 ° C. for 3 hours, and then diluted with toluene so that the solid content concentration became 30% while cooling. The obtained polyamideimide resin L had a glass transition temperature of 164 ° C., a logarithmic viscosity of 0.47 dl / g, and an acid value of 187 eq / 10 ⁶ g. Using this polyamide-imide resin L, an adhesive composition 1 having the same composition as that of Example 1 was prepared, and a copper-clad laminate was prepared and tested in the same manner as in Examples 1 to 10. Went. Table 1 shows the measurement results of adhesive strength, solder resistance after humidification, and migration resistance. The phosphorus content relative to the total solid content of the adhesive composition was 2.7% by weight.

The results of the above examples are summarized in Table 1.

As is apparent from the results of the examples, according to the present invention, low temperature adhesion and heat resistance to metal and polyimide films, particularly solder resistance after humidification treatment and migration resistance characteristics under high temperature and high humidity. It is possible to provide excellent inks, adhesive compositions and adhesive sheets useful for circuit boards, coverlay films, glass cloth impregnated prepregs, and printed circuit boards using these.

Claims

A polyamide-imide resin having a carboxyl group in a side chain having a logarithmic viscosity of 0.2 dl / g or more and an acid value of 400 equivalent / 10 6 g to 1000 equivalent / 10 6 g.
The polyamideimide resin according to claim 1, wherein 3 to 30 mol% of the acid component is trimellitic acid when the total acid component of the polyamideimide resin is 100 mol%.
The polyamide-imide resin according to claim 2, wherein the trimellitic acid is obtained by opening the trimellitic acid anhydride by adding water to the trimellitic acid anhydride.
The polyamideimide resin according to claim 1, wherein 3 to 30 mol% of the acid component is dimethylolbutanoic acid when the total acid component of the polyamideimide resin is 100 mol%.
Claim 1 obtained by reacting trimellitic anhydride and / or tetracarboxylic anhydride with a diamine component and / or diisocyanate component to form a prepolymer, and then chain-extending the prepolymer with alkylene glycol. The polyamide-imide resin described.
6. The polyamideimide resin according to claim 5, wherein the alkylene glycol is at least one selected from the group consisting of polyethylene glycol, polypropylene glycol and polytetramethylene glycol having a number average molecular weight of 400 to 10,000.
An adhesive composition comprising the polyamide-imide resin according to any one of claims 1 to 6 containing at least one compound selected from the group consisting of a polyfunctional epoxy compound, a polyfunctional isocyanate compound, and a melamine compound.
The adhesive composition according to claim 7, comprising an organic phosphorus compound in a phosphorus content of 1 wt% or more and 3 wt% or less based on the total solid content of the adhesive composition.
An ink for printed circuit boards, wherein the adhesive composition according to claim 7 or 8 contains inorganic and / or organic fine particles, and has a thixotropic index of 1.2 or more and 3.0 or less.
A coverlay film using the adhesive composition according to claim 7 or 8.
An adhesive sheet obtained by applying and drying the adhesive composition according to claim 7 or 8 on a polypropylene film, a release paper, or a release film.
A printed circuit board using the adhesive composition according to claim 7.