JP2007146188A - Method for producing modified polyimide resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing modified polyimide resin sufficiently satisfying required properties as an overcoat agent for wiring circuits requiring flexibility, such as a flexible wiring circuit substrate and a film carrier. <P>SOLUTION: The method for producing a modified polyimide resin comprises reacting a component [1] comprising an isocyanate-containing product (isocyanate equivalent number: X equivalent), obtained by reacting a bifunctional hydroxy-terminated polybutadiene having 800-5,000 number-average molecular weight with a diisocyanate compound at a ratio of hydroxy:isocyanate=1:1.5-2.5 based on equivalent number, with a component [2] comprising a tetrabasic acid dianhydride (acid anhydride equivalent: Y equivalent) in a condition range in which the equivalent numbers are Y>X≥Y/3, 0<X and 0<Y. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a modified polyimide resin useful for imparting heat resistance, flexibility and low shrinkage during curing.

  Conventionally, the surface protection film of flexible printed circuit boards has been made by punching a die that matches a pattern with a polyimide film called a coverlay film, and then pasting it with an adhesive, or by applying ultraviolet light with flexibility. It has been formed by a method in which an overcoat agent mainly composed of a curable resin or a thermosetting resin is applied and cured by a screen printing method. However, the coverlay film method is not preferable in terms of workability, and the method using an overcoat agent is still insufficient in terms of warping during curing and flexibility, and is flexible enough to satisfy the required performance. A method for forming a surface protective film on a printed circuit board has not been found.

On the other hand, in recent years, a TAB method using a film carrier suitable for high density and thinning as a package for a liquid crystal driving IC has been increasingly used. The basic structure of a film carrier mainly consists of a heat-resistant insulating film substrate such as polyimide and a conductor such as copper foil bonded via an adhesive mainly composed of epoxy resin. The wiring pattern is formed by etching. The film carrier device is manufactured by connecting an IC to this tape carrier and sealing it with a sealing resin. However, before the IC connection, the film carrier device is reliable due to pattern short circuit, corrosion, migration, and whisker. In order to prevent the deterioration of the property, it is common to form a surface protective film on this film carrier with an overcoat agent. As the overcoat agent used for the film carrier, an epoxy type or a polyimide type is used. The former is a warp during curing and the flexibility of the coating film, and the latter is an adhesive property with an IC sealing resin. There is nothing that is satisfactory in terms of operating characteristics and work characteristics, and the current situation is that a plurality of overcoat agents are used together to make up (Patent Document 1).
JP-A-6-283575

  Thus, the object is to develop a method for producing a modified polyimide resin that sufficiently satisfies the required characteristics as an overcoat agent for wiring circuits that require flexibility, such as flexible wiring circuit boards and film carriers.

As a result of intensive studies to solve the above problems, the present inventors have found that the general formula (4)
(Where R1 is a residue excluding the acid anhydride group of tetrabasic acid dianhydride, R2 is a residue excluding the isocyanate group of the diisocyanate compound, and R3 is a residue excluding the hydroxyl group of the hydroxyl-terminated polybutadiene. L2 and M2 represent the composition ratio of the polybutadiene unit and the polyimide unit, and n3 represents the degree of polymerization, where L2 + M2 = 1, 0 <L2 <1, 0 <M2 <1, and 1 ≦ n3 ≦. 1000.)
The modified polyimide resin having a polybutadiene skeleton represented by is found to be very useful as a component of an overcoat agent used for a flexible printed circuit board or a tape carrier, and (A) the number average molecular weight is 1000 to 8000 per molecule. A polybutadiene polyol having 2 to 10 hydroxyl groups, (B) a modified polyimide resin represented by the general formula (4), and (C) a number average molecular weight of 1000 to 8000 and 2 to 10 hydroxyl groups per molecule. Resin with performance that can sufficiently satisfy various characteristics such as flexibility, low shrinkage during curing, adhesion, electrical insulation, chemical resistance, heat resistance, etc. by mixing polybutadiene polyblock isocyanate at a predetermined ratio It has been found that a composition can be obtained.

That is, in the present invention, the component component [1] is reacted with a bifunctional hydroxyl-terminated polybutadiene having a number average molecular weight of 800 to 5000 and a diisocyanate compound in an equivalent number of hydroxyl group: isocyanate group = 1: 1.5 to 2.5. The isocyanate group-containing product (isocyanate equivalent number: X equivalent) and the component [2] tetrabasic acid dianhydride (acid anhydride equivalent number: Y equivalent) obtained when the equivalent number is Y> X ≧ Y / 3, The present invention relates to a method for producing a modified polyimide resin, characterized by reacting in the range of 0 <X, 0 <Y.

Component [1] A general formula (1) obtained by reacting a bifunctional hydroxyl-terminated polybutadiene having a number average molecular weight of 800 to 5000 with a diisocyanate compound in an equivalent number and hydroxyl group: isocyanate group = 1: 1.5 to 2.5. 3)
(Here, R2 is a residue excluding the isocyanate group of the diisocyanate compound, R3 is a residue excluding the hydroxyl group of the hydroxyl-terminated polybutadiene, and n2 represents the degree of polymerization. In this case, 0 ≦ n2 ≦ 100. is there.)
And an isocyanate group-containing product (isocyanate equivalent number: X equivalent) and [2] general formula (1)
(R1 represents a residue obtained by removing the acid anhydride group of tetrabasic acid dianhydride.)
Wherein the tetrabasic acid dianhydride (acid anhydride equivalent number: Y equivalent) is reacted in the range of the equivalent number Y> X ≧ Y / 3, 0 <X, 0 <Y, General formula (2)
(L1 and M1 represent the composition ratio of the polybutadiene unit and the polyimide unit, and n1 represents the degree of polymerization. At this time, L1 + M1 = 1, 0 <L1 <1, 0 <M1 <1, and 1 ≦ n1 ≦ 10000. is there.)
And a method for producing a modified polyimide resin in which component [3] an isocyanate group-containing product or / and a diisocyanate compound (isocyanate equivalent number: Z equivalent) are reacted.

  The overcoat agent containing the modified polyimide resin obtained by the production method of the present invention is particularly excellent in flexibility, warping upon curing, and excellent in chemical resistance, heat resistance, electrical insulation, adhesion, and flexible circuit. It is suitable as an overcoat agent, and can be expected sufficiently as an overcoat agent for a film carrier.

Hereinafter, the present invention will be described in detail. The modified polyimide resin in this invention is mainly composed of [a] tetrafunctional dianhydride [c] diisocyanate compound represented by the general formula (1), bifunctional hydroxyl-terminated polybutadiene [b] having a number average molecular weight of 800 to 5000. In order to show the modified polyimide resin represented by the general formula (2) obtained by reacting the components and efficiently incorporate the polyimide unit into the resin, it is preferably synthesized by the following method. That is, the modified polyimide resin represented by the general formula (2) is a hydroxyl group: isocyanate group = 1: 1.5-2.2 with a bifunctional hydroxyl-terminated polybutadiene having a number average molecular weight of 800-5000 and a diisocyanate compound in an equivalent number. 5 to obtain an isocyanate group-containing product (isocyanate equivalent number: X equivalent) represented by the general formula (3), and this and a tetrabasic acid dianhydride (acid anhydride) represented by the general formula (1) Equivalent number: Y equivalent). In some cases, in the above reaction, the amount of the compound represented by the general formula (3) and the compound represented by the general formula (1) is set to the number of equivalents of Y> X ≧ Y / 3, 0 <X, 0 <Y. To obtain a modified polyimide resin represented by the general formula (4), followed by [3] an isocyanate group-containing product represented by the general formula (3) and / or a diisocyanate described in [c]. A modified polyimide resin represented by the general formula (2) can also be produced by reacting a compound (isocyanate equivalent number: Z equivalent) with this. In addition, although the number of equivalents of the isocyanate to be reacted with the general formula (4) is expressed as Z equivalent, this is a single use of the isocyanate group-containing product represented by the general formula (3) and the diisocyanate compound described in [c]. Or the total number of equivalents when used together. Thus, if the reaction conditions are not taken into account, various side reactions such as the reaction between the acid anhydride group and the hydroxyl group and the reaction between isocyanates occur, or the reaction between the isocyanate group and the acid anhydride group takes precedence and only the polyimide unit is present. Since precipitation may occur, the polyimide unit cannot be efficiently incorporated into the resin skeleton, and it may not be possible to obtain a resin having excellent characteristics such as mechanical characteristics and hydrolysis resistance. .

  In general, when the molecular weight of the polymer is too large, the viscosity of the resin solution increases, so that it becomes difficult to use the polymer as a resin composition such as an overcoat agent. For this reason, it is preferable that the resin raw material component ratio is appropriately broken so that the molecular weight does not increase too much. That is, [1] an isocyanate group-containing product represented by the general formula (3) (isocyanate equivalent number: X equivalent), and [2] a tetrabasic acid dianhydride (acid anhydride equivalent) represented by the general formula (1). The amount charged in the reaction with (number: Y equivalent) is preferably in the range of the equivalent number of Y> X ≧ Y / 3. In addition, when [3] the isocyanate group-containing product represented by the general formula (3) or / and the diisocyanate compound described in [c] (number of isocyanate equivalents: Z equivalent) is further reacted, [1] [2] The addition amount of [3] is preferably in the range of the number of equivalents of Y> (X + Z) ≧ Y / 3 and 0.2 ≦ (Z / X) ≦ 5. In the case of Y <X or Y <(X + Z), polymerization is performed in an isocyanate group-excess system, so that a side reaction is likely to occur and the reaction control is difficult. In the case of X <Y / 3, (X + Z) <Y / 3, Since the anhydride is excessively large, a sufficient molecular weight for exhibiting performance cannot be obtained. In the case of 0.2> (Z / X), since the ratio of the flexible butadiene skeleton is increased, a highly flexible resin is obtained, but it is insufficient in terms of heat resistance. In the case of / X)> 5, since the ratio of the polyimide skeleton is increased, the solubility in the solvent is poor, and the solution becomes highly viscous and the imide component is precipitated, making it difficult to handle.

  The bifunctional polybutadiene having a number average molecular weight of 800 to 5000 used for the synthesis of the isocyanate group-containing product represented by the general formula (3), which is the raw material [1] for synthesizing the modified polyimide resin in the present invention, Examples include hydrogenated unsaturated bonds such as G-1000, G-3000, GI-1000, GI-3000 (above, Nippon Soda Co., Ltd.), R-45EPI (Idemitsu Petrochemical Co., Ltd.) However, it is not limited to this.

  Examples of the diisocyanate compound used in the synthesis of the isocyanate group-containing product represented by the general formula (3), which is the raw material [1] for synthesizing the modified polyimide resin in the present invention, include toluene-2,4-diisocyanate and toluene-2,6. -Diisocyanate compounds such as diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and the like, are not limited thereto.

  Examples of the tetrabasic acid dianhydride represented by the general formula (1) used for the raw material [2] for synthesizing the modified polyimide resin in the present invention include pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, and biphenyl. Tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-cyclohexene-1,2-dicarboxylic anhydride, 3,3′-4, 4'-diphenylsulfonetetracarboxylic dianhydride, 1,3,3a, 4,5,9b-hexahydro-5- (tetrahydro-2,5-dioxo-3-furanyl) -naphtho [1,2-C] Examples include, but are not limited to, furan-1,3-dione.

  Examples of the diisocyanate compound described in [c] used for the synthetic polyimide resin raw material [3] in the present invention include toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, diphenylmethane. Although diisocyanates, such as diisocyanate and isophorone diisocyanate, are mentioned, it is not limited to this.

  The modified polyimide resin in the present invention is obtained by reacting three components of [a] a bifunctional hydroxyl-terminated polybutadiene having a number average molecular weight of 800 to 5000, [b] tetrabasic acid dianhydride, and [c] diisocyanate compound. Preferably, first, a bifunctional hydroxyl-terminated polybutadiene having a number average molecular weight of 800 to 5000 and a diisocyanate compound are charged in an equivalent number of hydroxyl groups: isocyanate groups = 1: 1.5 to 2.5, The reaction is carried out in an organic solvent at a reaction temperature of 80 ° C. or lower for 1 to 8 hours, and then the isocyanate group-containing polybutadiene resin solution obtained by this reaction is cooled to room temperature, and then in an equivalent ratio, it is in excess of the isocyanate groups. Add tetrabasic dianhydride, reaction catalyst, and organic solvent if necessary, and react at 120-150 ° C for 2-24 hours. Either complete the reaction of all isocyanate groups, or add a diisocyanate compound dropwise to the reaction product, and perform a polymerization reaction at 120 to 150 ° C. for 2 to 24 hours. It can be suitably obtained by setting the point that has been completed as the end. At this time, the number of equivalents of acid anhydride groups exceeds the same amount as the number of equivalents of isocyanate groups, and the number of equivalents of isocyanate groups is equal to or more than one third of the number of equivalents of acid anhydride. It is preferable.

  Examples of the organic solvent in the above reaction include N, N′-dimethylformamide, N, N′-diethylformamide, N, N′-dimethylacetamide, N, N′-diethylacetamide, dimethyl sulfoxide, diethyl sulfoxide, N Polar solvents such as methyl-2-pyrrolidone, tetramethylurea, γ-butyrolactone, cyclohexanone, diglyme, triglyme, carbitol acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate can be used alone or as a mixture . Further, these polar solvents can be used in combination with nonpolar solvents such as aromatic hydrocarbons.

  As a reaction catalyst in the above reaction, for example, tetotamethylbutanediamine, benzyldimethylamine, triethanolamine, triethylamine, N, N′-dimethylpiperidine, α-methylbenzyldimethylamine, N-methylmorpholine, triethylenediemine Tertiary amines such as dibutyltin laurate, dimethyltin dichloride, cobalt naphthenate, zinc naphthenate and the like can be used alone or in combination. Triethylenediamine is most preferred.

  Moreover, the modified polyimide resin-containing resin composition in the present invention has (A) a polybutadiene polyol having a number average molecular weight of 1000 to 8000 and 2 to 10 hydroxyl groups per molecule, and (B) the general formula (4). The modified polyimide resin shown, and (C) a polybutadiene polyblock isocyanate having 2 to 10 blocked isocyanate groups per molecule with a number average molecular weight of 1000 to 8000, and (A) component and The weight ratio of component (B) is (A) :( B) = 40: 60 to 90:10 as the solid content, and the amount of polyblock isocyanate is the number of hydroxyl equivalents of component (A) and acid anhydride of component (B). It is preferable that the equivalent number is 0.8 to 3.5 times the sum of the number of equivalents.

  The polybutadiene polyol (A) having a number average molecular weight of 1000 to 8000 in the above composition and having 2 to 10 hydroxyl groups per molecule has characteristics such as heat resistance and chemical resistance, and flexibility and flexibility. It is important for imparting both of the properties found in flexible resins such as low shrinkage. When the molecular weight is smaller than this range, or when the number of hydroxyl groups per molecule is larger than this range, the crosslink density at the time of curing increases, resulting in a harder cured product and the flexibility of the cured coating film. In addition, sufficient physical properties cannot be obtained with respect to low shrinkage during curing. On the other hand, when the molecular weight is larger than this range, or when the number of hydroxyl groups per molecule is smaller than this range, the crosslinking density at the time of curing is lowered, so that a more flexible cured product is obtained, but curing is performed. The heat resistance and chemical resistance of the coating film are significantly reduced. In addition, since the component (A) is a polybutadiene skeleton, there is an effect of further improving flexibility and low shrinkage during curing.

  The modified polyimide resin represented by the general formula (4) in the composition has few functional groups, has an appropriate molecular weight, and possesses flexibility derived from a butadiene skeleton. It is important to give low shrinkage at the time. In addition, since it has an imide skeleton that imparts heat resistance and chemical resistance, it is also important for achieving a certain degree of compatibility between flexibility, heat resistance, and chemical resistance. In addition, since this resin has a polybutadiene unit, (A) the number average molecular weight is 1000 to 8000, polybutadiene polyol having 2 to 10 hydroxyl groups per molecule, and (C) the number average molecular weight is 1000 to 8000. 8000, because it is very homogeneously mixed with polybutadiene polyblocked isocyanate having 2 to 10 blocked isocyanate groups per molecule, it is characterized by being firmly incorporated into the crosslinking system made by component (A) and component (C) . For this reason, with regard to heat resistance, chemical resistance, moisture resistance, etc., which are excellent characteristics of the cross-linking system formed by the component (A) and the component (C), the addition of the component (B) is flexible while minimizing the deterioration of its physical properties. It is more effective in imparting low shrinkage during curing and curing.

  The polybutadiene polyblock isocyanate (C) having a number average molecular weight of 1000 to 8000 in the above composition and having 2 to 10 blocked isocyanate groups per molecule has characteristics such as heat resistance and chemical resistance found in rigid resins. It is important for imparting both of the properties found in flexible resins such as flexibility and low shrinkage. When the molecular weight is smaller than this range, or when the number of hydroxyl groups per molecule is larger than this range, the crosslink density at the time of curing increases, resulting in a harder cured product and the flexibility of the cured coating film. In addition, sufficient physical properties cannot be obtained with respect to low shrinkage during curing. On the other hand, when the molecular weight is larger than this range, or when the number of hydroxyl groups per molecule is smaller than this range, the crosslinking density at the time of curing is lowered, so that a more flexible cured product is obtained, but curing is performed. The heat resistance and chemical resistance of the coating film are significantly reduced. In addition, since the component (A) is a polybutadiene skeleton, there is an effect of further improving flexibility and low shrinkage during curing.

  When only the polybutadiene polyol (A) is cured alone with the polybutadiene polyisocyanate (B), the cured product has a relatively good balance of heat resistance, chemical resistance and flexibility, and low shrinkage during curing. It is necessary to combine with the modified polyimide resin (B) because it is a level that cannot be said to be fully satisfactory in terms of flexibility and low shrinkage during curing. That is, (A) :( B) = 40: 60 to 90:10 are preferably mixed and used, and when the polyol (A) is less than this range, the crosslinking density is too low, so the coating film The properties such as heat resistance and chemical resistance are significantly reduced. Moreover, the quantity of polybutadiene polyblock isocyanate (C) shall be 0.8-3.5 times equivalent number with respect to the sum of the hydroxyl equivalent number of a component (A), and the acid anhydride equivalent number of a component (B). The crosslink density is too low in both cases where the amount is higher and lower than this, and the properties such as heat resistance and chemical resistance of the coating film are remarkably reduced.

  Any polybutadiene polyol (A) may be used as long as it has a number average molecular weight of 1000 to 8000, a number of hydroxyl groups of 2 to 10 per molecule, and a butadiene skeleton. -1000, GI-1000, GQ-1000 (above, manufactured by Nippon Soda Co., Ltd.), R-45EPI (produced by Idemitsu Petrochemical Co., Ltd.), etc., but are not limited thereto. .

  The polybutadiene polyblock isocyanate (C) is obtained by blocking an isocyanate group-containing polybutadiene polyisocyanate with a blocking agent. Examples of the polybutadiene polyisocyanate include toluene-2,4-diisocyanate, toluene-2,6. -Diisocyanates such as diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, those obtained by making the diisocyanate trifunctional or more utilizing the cyclization trimerization reaction of the isocyanate group, and various isocyanate groups A polyfunctional butadiene having a number average molecular weight of 600 to 7000, and a polybutadiene having a number average molecular weight of 3 or more. TP-1002 and (manufactured by Nippon Soda Co. (Ltd.)), HTP-9, HTP-5MLD, UNIMAX P (manufactured by Idemitsu Petrochemical Co., Ltd.) and the like. The blocking agent is preferably a compound having only one active hydrogen in one molecule capable of reacting with an isocyanate group and dissociating again at a temperature of 170 ° C. or less after reacting with the isocyanate group, ε-caprolactam, Examples include diethyl malonate, ethyl acetoacetate, acetoxime, methyl ethyl ketoxime, phenol, cresol and the like. However, it is not limited to this

  In addition to the above essential elements, the present invention may add a polyol and isocyanate curing accelerator, a filler, an additive, a thixotropic agent, a solvent, and the like as necessary. In particular, in order to further improve the bending resistance, it is preferable to add rubber fine particles, and to further improve the adhesion to the base copper circuit, the base substrate such as polyimide and polyester film, and the adhesive layer. Therefore, it is preferable to add polyamide fine particles.

  As the rubber fine particles, what is a fine particle of a resin that is chemically insoluble and infusible in an organic solvent by subjecting a resin exhibiting rubber elasticity such as acrylonitrile butadiene rubber, butadiene rubber, acrylic rubber, etc. For example, XER-91 (made by Nippon Synthetic Rubber Co., Ltd.), Staphyloid AC3355, AC3832, IM101 (above, Takeda Pharmaceutical Co., Ltd.) Paraloid EXL2655, EXL2602 (above, Kureha Chemical Industry) However, it is not limited to these.

  The polyamide fine particles may be any fine particles of resin having an amide bond, such as an aliphatic polyamide such as nylon, an aromatic polyamide such as Kevlar, and a polyamideimide, and the like, for example, , VESTOSINT 2070 (manufactured by Daicel Huls Co., Ltd.), SP500 (manufactured by Toray Industries, Inc.) and the like, but are not limited thereto.

  Hereinafter, the production examples of the modified polyimide resin and polyblock isocyanate in the present invention and the examples of the present invention will be described below together with comparative examples to explain the present invention more specifically.

<Production of modified polyimide resin represented by general formula (4) (varnish E)>
In a reaction vessel, 50 g of G-3000 (OH-terminated polybutadiene, Mn = about 3000, OH equivalent = 1798 g / eq., Solid content 100 w%: Nippon Soda Co., Ltd.) and Ipsol 150 (Idemitsu Petrochemical Co., Ltd.) (Made) 23.5 g and dibutyltin laurate 0.007 g are mixed and dissolved uniformly. When the temperature becomes uniform, the temperature is raised to 50 ° C., and while stirring, 4.8 g of toluene-2,4-diisocyanate (NCO equivalent = 87.08 g / eq.) Is added and the reaction is performed for 2 to 4 hours. The reaction was then cooled to room temperature and 8.83 g benzophenone tetracarboxylic dianhydride (acid anhydride equivalent 161.1), 0.07 g triethylenediamine and 74.09 g triglyme were added to it. While stirring, the temperature is raised to 130 ° C. and the reaction is carried out for 2 to 6 hours. When the disappearance of the NCO peak at 2250 cm −1 was confirmed by FT-IR, 1.42 g of toluene-2,4-diisocyanate (NCO equivalent = 87.08 g / eq.) Was further added, and again at 130 ° C., 2 Confirm disappearance of NCO by FT-IR while stirring for ˜6 hours. The confirmation of NCO disappearance is regarded as the end point of the reaction, and this is cooled to room temperature and then filtered through a 100 mesh filter cloth to obtain a modified polyimide resin (varnish E) (FIG. 1) shown by the general formula (4). It was.
Properties of resin varnish E: logarithmic viscosity = 0.31 (30 ° C, NMP solution)
Acid anhydride equivalent (including solvent) = 14708 g / eq.
Solid content = 40w%
*) The polymer solution used for the logarithmic viscosity measurement was prepared by pouring varnish E into methanol to precipitate only the resin solids, filtering and drying, and then dissolving in N-methyl-pyrrolidone at a concentration of 0.5 g / dL. Prepared.

<Production of blocked isocyanate (varnish F)>
In a reaction vessel, 1000 g of HTP-9 (NCO-terminated polybutadiene, NCO equivalent = 467 g / eq., Solid content = 100 w%: manufactured by Idemitsu Petrochemical Co., Ltd.) and ethyl diglycol acetate (manufactured by Daicel Chemical Industries, Ltd.) ) 216 g and dibutyltin laurate 0.1 g are mixed and dissolved uniformly. When the temperature became uniform, the temperature was raised to 70 ° C., 224 g of methyl ethyl ketoxime (molecular weight 87.12) was added dropwise over 2 hours while stirring, and further maintained for 1 hour, 2250 cm− from FT-IR shown in FIG. When disappearance of NCO peak 1 was confirmed, the temperature was lowered to obtain blocked isocyanate (varnish F).
Properties of resin varnish G: NCO equivalent = 672.5 g / eq.
Solid content = 85w%

(Evaluation method of coating film)
(1) Warpage amount due to curing shrinkage: It was applied on a polyimide film of 35 mm × 60 mm × 75 μm at 25 mm × 35 mm × 25 μm, and the amount of warpage after curing was measured.
(2) Bending resistance test: Mandrel test. The bending test is performed in the range of 1 to 1/8 inch diameter. → The display shows the minimum diameter where cracks do not occur.
(3) Electrical insulation: It is applied to a comb-shaped electrode having a conductor width of 0.318 mm, and the electrical resistance after 1 hour of boiling is measured.
(4) Chemical resistance: The coating film is rubbed with a cloth soaked with acetone or isopropanol. → ○: No abnormality, ×: Coating film deterioration
(5) Solder heat resistance: Flux JS-64MS-S was applied to the coating film and immersed in a solder bath at 260 ° C. for 10 seconds.
→ ◎: No abnormality, ○: Slight swelling, x: Severe swelling
(6) Bending resistance: Performed according to JIS C5016. The radius of the bending surface is 0.38 mm, and the number of bendings until a crack occurs is measured.
→ ×: 10 times or less, Δ: 10 to 1000 times, ○: 1000 to 2000 times, ◎: 2000 times or more
(7) Adhesiveness (IC sealing resin): Copper is etched, and the resin composition is applied to a TAB tape having an exposed adhesive layer to a thickness of about 25 μm and cured. An IC sealing resin is applied on this coating film to a thickness of about 200 μm and cured to create a test piece. The test piece is bent by hand and the sealing resin is peeled off.
IC sealing resin A: XS8103 (manufactured by NAMICS Co., Ltd.)
IC sealing resin B: XS8107 (manufactured by NAMICS Co., Ltd.)
→ ×: Interfacial peeling between composition coating film / sealing resin Δ: Cohesive failure and interfacial peeling between the composition coating film and sealing resin coexist,
Cohesive failure as a ratio <interface peeling ○: cohesive failure and interface peeling of the composition coating film and the sealing resin coexist,
Cohesive failure as a ratio> Interfacial debonding
A: Cohesive failure in each of the composition coating film and the sealing resin
(8) Adhesion (on copper and polyimide): Conforms to JIS D0202.
Polyimide: Upilex S (manufactured by Ube Industries, Ltd.)
→ ×: 0/100 to 50/100,
Δ: 51/100 to 99/100,
○: 100/100

<Preparation of curable resin composition>
Component A: Polybutadiene polyol / GQ-2000 (OH-terminated polybutadiene, Mn = about 2500, OH equivalent = 1042 g / eq., Solid content = 45 w%: manufactured by Nippon Soda Co., Ltd.)
Component B: Modified polyimide resin / resin varnish E (acid anhydride terminal resin, acid anhydride equivalent (including solvent) = 14708 g / eq., Solid content = 40 w%)
Polyols other than A and B components, LIR-506 (OH group-containing polyisoprene, Mn = about 25000, OH equivalent = 4237 g / eq. Solid content 100 w%)
Component C: Polybutadiene polyblock isocyanate / resin varnish F (NCO-terminated polybutadiene, NCO equivalent = 672.5 g / eq., Solid content = 85 w%)
The above polyol, modified polyimide resin, and polyblock isocyanate are appropriately blended, and as other components, dibutyltin laurate as a curing accelerator, Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) as an anti-sagging agent, and a viscosity adjusting solvent Carbitol acetate was added in an appropriate amount for each formulation, mixed, and kneaded using three rolls to prepare Samples A1 to A3 shown in Table 1. This sample A1-3 was apply | coated to arbitrary base materials so that it might become a film thickness of about 25 micrometers at the time of drying, and it hardened | cured on the conditions for 150 degreeC x 60 minutes, and produced the test sample. The measurement results are shown in Table 2. In addition, the numerical value in a table | surface represents the weight part containing the solvent content in a raw material.

*) The numerical values in the table represent parts by weight including the solvent content in the raw material.

(Comparative Examples 1-4)
In accordance with the examples, each sample B1-2 was prepared with the formulation shown in Table 1, and as an example of an overcoat agent generally used in current film carriers, CCR-232GF (Epoxy system manufactured by Asahi Chemical Research Laboratory) ) In Comparative Example B3, FS-100L (manufactured by Ube Industries, polyimide system) in Comparative Example 4, and the results are also shown in Table 2.

The infrared absorption spectrum (FT-IR) of the modified polyimide resin represented by the general formula (4) of the present invention is shown.

Claims (5)

Component [1] Contains an isocyanate group obtained by reacting a bifunctional hydroxyl-terminated polybutadiene having a number average molecular weight of 800 to 5,000 with a diisocyanate compound in an equivalent number of hydroxyl group: isocyanate group = 1: 1.5 to 2.5. When the product (isocyanate equivalent number: X equivalent) and component [2] tetrabasic acid dianhydride (acid anhydride equivalent number: Y equivalent) are used, the equivalent number is Y> X ≧ Y / 3, 0 <X, 0 < A method for producing a modified polyimide resin, characterized by reacting in the range of Y. Component [1] A general formula (1) obtained by reacting a bifunctional hydroxyl-terminated polybutadiene having a number average molecular weight of 800 to 5000 with a diisocyanate compound in an equivalent number and hydroxyl group: isocyanate group = 1: 1.5 to 2.5. 3)
(Here, R2 is a residue excluding the isocyanate group of the diisocyanate compound, R3 is a residue excluding the hydroxyl group of the hydroxyl-terminated polybutadiene, and n2 represents the degree of polymerization. In this case, 0 ≦ n2 ≦ 100. is there.)
And an isocyanate group-containing product (isocyanate equivalent number: X equivalent) and [2] general formula (1)
(R1 represents a residue obtained by removing the acid anhydride group of tetrabasic acid dianhydride.)
Wherein the tetrabasic acid dianhydride (acid anhydride equivalent number: Y equivalent) is reacted in the range of the equivalent number Y> X ≧ Y / 3, 0 <X, 0 <Y, General formula (2)
(L1 and M1 represent the composition ratio of the polybutadiene unit and the polyimide unit, and n1 represents the degree of polymerization. At this time, L1 + M1 = 1, 0 <L1 <1, 0 <M1 <1, and 1 ≦ n1 ≦ 10000. is there.)
The manufacturing method of the modified polyimide resin shown by these. The diisocyanate compound is a diisocyanate compound selected from the group consisting of toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, and tetrabasic acid dianhydride The product is pyromellitic dianhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3 -Methyl-cyclohexene-1,2-dicarboxylic anhydride, 3,3'-4,4'-diphenylsulfone tetracarboxylic dianhydride and 1,3,3a, 4,5,9b-hexahydro-5- ( Tetrahydro-2,5-di Kiso-3-furanyl) - naphtho is [1,2-C] tetrabasic acid dianhydride selected from the group consisting of furan-1,3-dione, according to claim 1 or 2 The method according. After obtaining the modified polyimide resin according to the method according to any one of claims 1 to 3, the modified polyimide resin is further mixed with a component [3] isocyanate group-containing product or / and a diisocyanate compound (isocyanate equivalent number: Z equivalent) is reacted, a method for producing a modified polyimide resin. The method according to claim 4, wherein the number of equivalents is such that Y> (X + Z) ≥Y / 3, 0.2≤ (Z / X) ≤5, 0 <X, 0 <Y, 0≤Z.