JP2022138123A - Polyimide block copolymer, epoxy resin composition, and cured product thereof, semiconductor sealing material and method for producing polyimide block copolymer - Google Patents

Abstract

To provide a polyimide block copolymer that has excellent hydrolysis resistance and high dispersibility in an epoxy resin composition and a method for producing the same; and also provide a cured epoxy resin and a semiconductor making it possible to suppress bleedout and achieve reduced stress and increased toughness when adding the polyimide block copolymer to the epoxy resin composition.SOLUTION: A polyimide block copolymer has a constitutional unit having a silicone skeleton and a constitutional unit having a polyalkylene glycol skeleton and includes imide bonds.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a polyimide block copolymer, an epoxy resin composition containing the block copolymer, a cured product thereof, and a semiconductor sealing material.

A semiconductor encapsulant that protects a semiconductor from heat and impact generally comprises an epoxy resin, a curing agent, a filler, and various additives such as a stress reducing agent and a flame retardant. 2. Description of the Related Art In recent years, semiconductors have become more highly integrated, and the chip size of semiconductors has correspondingly increased. On the other hand, electronic devices that serve as semiconductor packages have become smaller and thinner. Therefore, there is a problem that cracks are likely to occur due to thermal shock during package molding, and damage to the package is likely to occur due to peeling of the lead frame or chip from the sealing resin. Against this background, further improvements in low stress, fluidity, heat resistance, etc. are required for encapsulants for semiconductors that operate at higher temperatures, such as automotive semiconductors and power semiconductors, which will increase in the future. It is Under such circumstances, as a stress reducing agent, a polysiloxane block that has both flexibility and good dispersibility in epoxy resin, has a functional group, is incompatible with epoxy resin but has excellent flexibility, A technique for reducing the elastic modulus of a semiconductor encapsulant using a multi-block copolymer having a polyalkylene glycol block that has a functional group, is compatible with epoxy resin and has excellent flexibility has been disclosed (Patent Document 1 ).

In addition, polyimide has excellent properties such as high heat resistance, high chemical resistance, and excellent mechanical strength. Polyimide copolymers obtained by copolymerizing an aromatic diamine component as a hard segment and a polyalkylene glycol component or a polysiloxane component as a soft component have been disclosed (Patent Documents 2 to 4).

WO2018/221373 Japanese Patent Application Laid-Open No. 2005-330421 JP 2009-224460 A JP 2005-120176 A

However, although the block copolymer described in Patent Document 1 is excellent in flexibility and dispersibility in epoxy resin, it has a problem in hydrolysis resistance in applications such as power semiconductors that require stability during high heat use. rice field.

In addition, the block polyimide-polysiloxane copolymers described in Patent Documents 2 and 3 have a siloxane component introduced as a soft segment, but have poor compatibility with epoxy resins and bleed out from cured epoxy resins. There was a problem of hoarding. Furthermore, the polyimide in which the polysiloxane component and the polyalkylene glycol component are introduced as the soft segment described in Patent Document 4 contains 55% by weight or more of the aromatic component in the polymer, and the polysiloxane component is 15% by weight or less. It was not flexible enough to be used as a stress agent.

Therefore, in view of these problems of the prior art, the present invention provides a polyimide block copolymer that has excellent hydrolysis resistance and high dispersibility in an epoxy resin composition. In addition, when the polyimide block copolymer is added to an epoxy resin composition, bleedout is suppressed, and an epoxy resin cured product and a semiconductor capable of exhibiting low stress and high toughness are provided.

In order to solve the above problems, the present inventors made intensive studies, and as a result, arrived at the following invention. That is, the present invention provides a polyimide block copolymer obtained from a precursor represented by any one of general formula (1), (2) or (3).

(n represents 2 to 30, m represents 5 to 100, p and r represent the number of repeating units of 0 or 1. R ₁ is a linear or branched alkyl group having 2 to 10 carbon atoms. R ₂ is is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and R ₃ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group, or a divalent group having 1 to 10 carbon atoms. is a group selected from the hydrocarbon ether groups of R ₄ is a phenyl group, a biphenyl group, a diphenyl ether group, a benzophenone group, and a linear, branched or cyclic aliphatic alkylene group having 1 to 40 carbon atoms; A plurality of R ₁ , R ₂ , R ₃ and R ₄ may be the same or different.)

An epoxy resin composition obtained by blending the above polyimide block copolymer with an epoxy resin, an epoxy resin cured product obtained by curing the epoxy resin composition, and a semiconductor sealing material.

ADVANTAGE OF THE INVENTION According to this invention, the polyimide block copolymer which is excellent in hydrolysis resistance and high dispersibility to an epoxy resin composition can be provided. In addition, when the polyimide block copolymer is added to an epoxy resin composition, it is possible to suppress bleeding out, and to provide an epoxy resin cured product and a semiconductor capable of exhibiting low stress and high toughness.

The present invention will be described in detail below.

(1) Polyimide block copolymer The polyimide block copolymer of the present invention is
A polyimide block copolymer obtained from a precursor represented by any one of general formula (1), (2) or (3).

(n represents 2 to 30, m represents 5 to 100, p and r represent the number of repeating units of 0 or 1. R ₁ is a linear or branched alkyl group having 2 to 10 carbon atoms. R ₂ is is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and R ₃ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group, or a divalent group having 1 to 10 carbon atoms. is a group selected from the hydrocarbon ether groups of R ₄ is a phenyl group, a biphenyl group, a diphenyl ether group, a benzophenone group, and a linear, branched or cyclic aliphatic alkylene group having 1 to 40 carbon atoms; A plurality of R ₁ , R ₂ , R ₃ and R ₄ may be the same or different.)

The multi-block copolymer referred to in the present invention contains two or more repeating structures derived from the precursor represented by any one of the general formulas (1), (2) and (3). AB type diblock copolymers and ABA type triblock copolymers containing one each are not called multiblock copolymers.

The polyimide block copolymer of the present invention is obtained by dehydrating and ring-closing the polyamic acid structure of the precursor represented by the general formula (1), (2) or (3), for example, general formulas (4) and (5) Or a polyimide block copolymer represented by (6) can be obtained, preferably general formula (7), (8) or (9).

(n represents 2 to 30, m represents 5 to 100, p and r represent the number of repeating units of 0 or 1. R ₁ is a linear or branched alkyl group having 2 to 10 carbon atoms. R ₂ is is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and R ₃ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group, or a divalent group having 1 to 10 carbon atoms. is a group selected from the hydrocarbon ether groups of R ₄ is a phenyl group, a biphenyl group, a diphenyl ether group, a benzophenone group, and a linear, branched or cyclic aliphatic alkylene group having 1 to 40 carbon atoms; A plurality of R ₁ , R ₂ , R ₃ and R ₄ may be the same or different.)

As the bonding mode of the structure derived from the block copolymer polysiloxane (A) and the structure derived from the polyalkylene glycol (B) of the present invention, it is derived from the amic acid structure generated by the reaction of the carboxylic anhydride group and the amino group. an amide bond formed by dehydration ring closure of amic acid, and an ester bond formed by reaction between a carboxylic anhydride group and a hydroxyl group. In the reaction between a carboxylic anhydride group and an amino group and the reaction between a carboxylic anhydride group and a hydroxyl group, a carboxyl group is produced as a result of these reactions. The block copolymer of the present invention has an amide bond or imide bond derived from an amic acid structure as a bond, and thus has high hydrolysis resistance. On the other hand, since the amic acid structure contains a carboxyl group, it is presumed that it is likely to react with the epoxy resin, but the elastic modulus of the epoxy resin composition tends to increase. Therefore, by dehydrating and ring-closing the amic acid structure to convert it to an imide bond to reduce the amount of carboxyl groups, it is possible to maintain high hydrolysis resistance derived from the excellent stability of the imide bond and achieve excellent flexibility. An imide bond is preferred as a bond in the block copolymer because a copolymer can be easily obtained. However, if there are too many imide bonds, the flexibility of the copolymer is impaired due to the rigidity of the imide bonds, so it is preferred that both the ester bonds and the imide bonds coexist in the polymer. The imide group in the polymer can be confirmed by detecting a peak derived from the imide group obtained by infrared spectroscopy (IR) measurement.

The weight average molecular weight (Mw) of the polyimide block copolymer of the present invention is 5,000 to 100,000 from the viewpoint of flexibility and heat resistance. The lower limit is preferably 7,000 or more, more preferably 10,000 or more, particularly preferably 15,000 or more, from the viewpoint of imparting flexibility when blended in an epoxy resin or the like. Preferably it is 20,000 or more. In addition, the upper limit is preferably 100,000 or less, more preferably 80,000 or less, from the viewpoint of obtaining good dispersibility in the epoxy resin and suppressing a decrease in fluidity of the epoxy resin composition. is more preferably 60,000 or less, particularly preferably 50,000 or less, and most preferably 40,000 or less. The weight-average molecular weight of the polyimide block copolymer referred to herein refers to the weight-average molecular weight measured by gel permeation chromatography using tetrahydrofuran (THF) as a solvent and converted to polymethyl methacrylate as a standard sample.

If it cannot be measured with tetrahydrofuran (THF), use dimethylformamide as a solvent, and if it still cannot be measured, use hexafluoroisopropanol.

The polyimide block copolymer of the present invention preferably has a molecular weight distribution (Mw/Mn) of 5 or less, more preferably 3 or less, and still more preferably 2 or less. Also, its lower limit is 1. The molecular weight distribution (Mw/Mn) is calculated from the weight average molecular weight (Mw) and number average molecular weight (Mn) measured as described above using gel permeation chromatography.

The functional group content of the polyimide block copolymer of the present invention, from the viewpoint of obtaining high flexibility and mechanical properties, and from the viewpoint of suppressing the bleeding out of the block copolymer from the epoxy resin cured product, the lower limit The value is 0.1 mmol/g or more, preferably 0.2 mmol/g or more, more preferably 0.3 mmol/g or more, still more preferably 0.5 mmol/g or more, and particularly preferably 0.6 mmol/g or more. be. In addition, if the content of the functional group is too high, it is presumed that the reaction with the epoxy resin becomes too strong, but it is preferable because the flexibility and the fluidity of the epoxy resin composition decrease. From the viewpoint that the content is not high, the upper limit is preferably 3.0 mmol/g or less, more preferably 2.5 mmol/g or less, still more preferably 2.2 mmol/g or less, and particularly preferably 2.0 mmol/g or less.

The term "functional group" as used herein refers to a terminal group derived from the copolymerization component of the block copolymer and a functional group newly generated by the reaction of the copolymer component, and the functional group content is It is the total content of all of these functional groups. The functional group possessed by the block copolymer of the present invention is at least one selected from a carboxyl group, a carboxylic anhydride group, a hydroxyl group and an amino group. For example, when the block copolymer contains only carboxyl groups as functional groups, the content of the carboxyl groups is the functional group content. When the block copolymer contains a plurality of functional groups such as a carboxyl group and a hydroxyl group, the sum of the respective functional group contents is taken as the functional group content contained in the block copolymer. Among them, the functional group is preferably a carboxyl group or a carboxylic acid anhydride group, and particularly preferably a carboxyl group, from the viewpoint that the effect of lowering the elastic modulus of the epoxy resin composition can be easily obtained.

The functional group content in the polyimide block copolymer can be determined by a known titration method. For example, when quantifying the carboxyl group, the block copolymer is dissolved in toluene or tetrahydrofuran (THF) and titrated with 0.1 mol/L of alcoholic potassium hydroxide using phenolphthalein as an indicator. Moreover, when quantifying a hydroxyl group, it can quantify by the method according to JISK0070.

Furthermore, it is possible to adjust the content of functional groups before and after synthesizing the block copolymer, depending on the intended use. For example, adjusting the weight average molecular weight of polysiloxane (A) having a functional group and / or polyalkylene glycol (B) having a functional group as a raw material, or adjusting the conversion rate to an imide bond by dehydration ring closure of the amic acid structure. By doing so, it is possible to adjust the functional group content of the resulting block copolymer.

As described above, the block copolymer of the present invention has the effect of not causing bleeding out from the cured epoxy resin. The presence or absence of bleeding out of the block copolymer from the cured epoxy resin is calculated by measuring the mass of the block copolymer dissolved in chloroform after immersing the cured epoxy resin in chloroform for one day and calculating the composition. If the mass of the block copolymer dissolved in chloroform is 5% by mass or more relative to the mass of the block copolymer in the epoxy resin cured product, bleeding out occurs, and if it is less than 5% by mass, bleeding occurs. Judge that there is no out. Less bleed-out is preferable from the viewpoint of quality improvement, in addition to reduction in elastic modulus and improvement in toughness of the cured epoxy resin product. Bleed-out is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.

The content of the structure derived from polysiloxane (A) in the block copolymer of the present invention is 100% by mass of the entire block copolymer, and the lower limit is 20% by mass or more, more preferably 30% by mass or more. be. The upper limit is 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less. If the content of the structure derived from polysiloxane (A) is too small, even if the block copolymer is added to the epoxy resin to prepare a cured product, the effect of lowering the elastic modulus due to the addition of the block copolymer is sufficient. It may not be exhibited and the function as a stress reducing agent may not be sufficient. In addition, when the content of the structure derived from polysiloxane (A) is too large, when the block copolymer is added to the epoxy resin, the dispersibility in the epoxy resin composition is not sufficient, and the block copolymer is If it is not finely dispersed, even if it is cured to produce a cured product, the effect of improving toughness by adding the block copolymer cannot be sufficiently exhibited. Otherwise, it causes bleeding out and cannot obtain a cured epoxy resin. The content of the structure derived from polysiloxane (A) in the polyimide block copolymer of the present invention can be calculated, for example, from a spectrum obtained by nuclear magnetic resonance (NMR).

The polyimide block copolymer of the present invention comprises a polysiloxane (A) having a hydroxyl group, an amino group, or a carboxylic anhydride group, and a hydroxyl group, an amino group, or a carboxylic anhydride group. In the case of a combination in which the functional groups of polysiloxane (A) and polyalkylene glycol (B) do not react directly, it has two carboxylic anhydride groups. A precursor of a polyimide block copolymer can be obtained by further reacting the compound (C) as a linking agent. The reaction between an amino group and a carboxylic anhydride group produces a carboxyl group and an amide bond, which is an amic acid structure, and the reaction between a hydroxyl group and a carboxylic anhydride group produces a carboxyl group and an ester bond. Therefore, the block copolymer precursor represented by the general formula (1) includes, for example, the polysiloxane (A) having a carboxylic anhydride group as a functional group and the polyalkylene having an amino group as a functional group. By reacting the glycol (B), the polysiloxane (A) having a hydroxyl group as a functional group, the polyalkylene glycol (B) having an amino group as a functional group and the compound having two carboxylic anhydride groups ( Combinations in which C) is reacted are preferred. Further, the block copolymer precursor represented by the general formula (2) includes, for example, the polysiloxane (A) having an amino group as a functional group and the polyalkylene glycol (B) having an amino group as a functional group. and the compound (C) having two carboxylic anhydride groups. Further, the block copolymer precursor represented by the general formula (3) includes, for example, the polysiloxane (A) having an amino group as a functional group, the polyalkylene glycol (B) having a hydroxyl group as a functional group, and the A combination of reacting compounds (C) having two carboxylic anhydride groups is preferred. An imide bond can be obtained by dehydrating and ring-closing the amic acid structure produced by these reactions.

(2) Polysiloxane (A)
Polysiloxane (A) used in the present invention is represented by general formula (10).

In the formula, m represents the number of repeating units of 5 to 100. R ₂ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group. R ₂ does not have a reactive functional group and does not react with any functional group present in the reaction system, because if R ₂ reacts with the functional group, the polymerization reaction is inhibited or the cross-linking reaction proceeds. , unfavorable. On the other hand, if the chain length of _R2 is too long, the resulting polysiloxane block copolymer is likely to be less fluid when added to the epoxy resin, which is not preferred. _R2 is preferably a propyl group, an ethyl group or a methyl group, most preferably a methyl group. R ₃ is a group selected from a divalent aliphatic or aromatic hydrocarbon group having 1 to 10 carbon atoms and a divalent hydrocarbon ether group having 1 to 10 carbon atoms. From the viewpoint of improving the dispersibility in the epoxy resin composition _, R3 is preferably butylene, propylene or ethylene, most preferably propylene or ethylene. The divalent hydrocarbon ether group is preferably a group represented by -(CH ₂ ) _a -O-(CH ₂ ) _b -, where 1≤a+b≤10. K represents any functional group selected from a hydroxyl group, an amino group and a carboxylic acid anhydride group. A plurality of R ₂ , R ₃ and K may be the same or different.

The weight average molecular weight of the polysiloxane (A) used in the present invention is not particularly limited, but the lower limit is preferably 500 or more, more preferably 800 or more, and still more preferably 1,000 or more. be. The upper limit of the weight average molecular weight is preferably 8,000 or less, more preferably 5,000 or less, still more preferably 4,000 or less, and most preferably 3,000 or less. When the weight-average molecular weight of the polysiloxane (A) having functional groups is small, the effect of lowering the elastic modulus is low even if the obtained block copolymer is added to the epoxy resin. Further, when the polysiloxane (A) having a functional group has a large weight-average molecular weight, the polysiloxane (A) having a functional group and the polyalkylene glycol (B) having a functional group undergo phase separation and react in a homogeneous state. does not proceed, the reactivity with the polyalkylene glycol (B) having a functional group deteriorates. Moreover, since the functional group content of the block copolymer to be obtained is low, the effect of improving the dispersibility in the epoxy resin described below is low. The weight average molecular weight of polysiloxane (A) having a functional group refers to the weight average molecular weight measured by gel permeation chromatography using tetrahydrofuran (THF) as a solvent and converted to polymethyl methacrylate.

The polysiloxane (A) used in the present invention is commercially available from Shin-Etsu Chemical Co., Ltd., X-22-168AS, KF-105, X-22-163A, X-22-163B, X-22- 163C, KF-8010, X-22-161A, X-22-161B, KF-8012, X-22-169AS, X-22-169B, X-22-160AS, KF-6001, KF-6002, KF- 6003, X-22-1821, X-22-162C, X-22-167B, X-22-167C, X-22-163, KF-6000, PAM-E, KF-8008, X-22-168A, X-22-168B, X-22-168-P5-B, X-22-1660B-3, X-22-9409, commercially available from Dow Corning Toray, BY16-871, BY16-853U, BY16-855, BY16-750, BY16-201 and the like.

(3) Polyalkylene glycol (B)
As the polyalkylene glycol (B) used in the present invention, it is preferable to use a polyalkylene glycol represented by general formula (11).

In the formula, n represents the number of repeating units from 2 to 30. R ₁ is a linear or branched C 2-10 alkyl group. When the number of carbon atoms in R ₁ is greater than 10, the polyalkylene glycol (B) is not compatible with the epoxy resin, and the resulting polysiloxane copolymer and the epoxy resin have poor dispersibility, resulting in poor dispersibility of the polysiloxane copolymer of the present invention. It becomes difficult to obtain the toughness improvement effect originally obtained by adding the polymer. Moreover, when the number of carbon atoms in R ₁ is small, the flexibility is lowered, which is not preferable. R ₁ preferably has 3 or 4 carbon atoms. K represents any functional group selected from a hydroxyl group, an amino group and a carboxylic acid anhydride group. A plurality of R ₁ may be the same or different.

As the polyalkylene glycol (B), when it has a polytetramethylene glycol and/or polypropylene glycol structure, it has excellent reactivity with the polysiloxane (A) used in the present invention, and does not use a metal catalyst as a reaction accelerator. It is preferable because the reaction proceeds and the polysiloxane (A) and the polyalkylene glycol (B) react to obtain a homogeneous block copolymer without using an organic solvent.

The weight average molecular weight of the polyalkylene glycol (B) used in the present invention is not particularly limited, but the lower limit is preferably 300 or more, more preferably 500 or more, and still more preferably 1,000 or more. is. The upper limit of the weight average molecular weight is preferably 20,000 or less, more preferably 10,000 or less, still more preferably 5,000 or less, and most preferably 3,000 or less. When the weight average molecular weight of the polyalkylene glycol (B) is small, the effect of improving the toughness when the obtained block copolymer is added to the epoxy resin is low. In addition, when the weight average molecular weight of the polyalkylene glycol (B) is large, the polysiloxane (A) and the polyalkylene glycol (B) used in the present invention undergo phase separation, and the reaction in a homogeneous system does not proceed, so the polysiloxane Reactivity with (A) becomes worse. Moreover, since the functional group content of the block copolymer to be obtained is low, the effect of improving dispersibility in the excellent epoxy resin is low. The weight average molecular weight of polyalkylene glycol (B) refers to the weight average molecular weight measured by gel permeation chromatography using tetrahydrofuran (THF) as a solvent and converted to polymethyl methacrylate.

The polyalkylene glycol (B) used in the present invention includes "Jeffamine" (registered trademark) D-400, "Jeffamine" (registered trademark) D-2000 and "Jeffamine" (registered trademark) XTJ-500 manufactured by Huntsman Corporation. (ED-600), "Jeffamine" (registered trademark) XTJ-502 (ED-2003), "Jeffamine" (registered trademark) EDR-148, "Jeffamine" (registered trademark) TJ-542, "Jeffamine" (registered trademark) ) XTJ-533, “Jeffamine” (registered trademark) XTJ-536, and the like. These polyalkylene glycols may be used alone or in combination of two or more.

Further, as the polyalkylene glycol (B) of the present invention, polyethylene glycol, polytetramethylene glycol, polypropylene glycol, polyneopentyl glycol and the like can be used.

(4) compound (C) having two carboxylic anhydride groups
In the polyimide block copolymer of the present invention, in the case of a combination in which the functional groups of polysiloxane (A) and polyalkylene glycol (B) do not react directly, the compound (C) having two carboxylic anhydride groups is linked. Further reacting as an agent, a polyimide block copolymer can be obtained.

The compound (C) having two carboxylic anhydride groups used in the present invention has two carboxylic anhydride groups that react with the functional groups of the polysiloxane (A) and/or the functional groups of the polyalkylene glycol (B). It is a molecule that possesses The obtained block copolymer has a structure derived from the compound (C) having two carboxylic anhydride groups in addition to the structure derived from the polysiloxane (A) and the structure derived from the polyalkylene glycol (B). Become.

It is preferable that the compound (C) dissolves in both the polysiloxane (A) and the polyalkylene glycol (B) during the reaction, because the reaction proceeds easily. Moreover, you may use multiple types of a compound (C).

Specific examples of the compound (C) having two carboxylic anhydride groups include pyromellitic dianhydride, 4,4'-oxydiphthalic anhydride, 3,3',4,4'-biphenyltetra Carboxylic acid dianhydride, 2,2'-dimethyl-3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 5,5'-dimethyl-3,3',4,4'-biphenyltetra Carboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, 2,2',3,3'-biphenyltetracarboxylic dianhydride, 3,3',4,4 '-diphenyl ether tetracarboxylic dianhydride, 2,3,3',4'-diphenyl ether tetracarboxylic dianhydride, 2,2',3,3'-diphenyl ether tetracarboxylic dianhydride, 3,3' ,4,4′-benzophenonetetracarboxylic dianhydride, 2,2′,3,3′-benzophenonetetracarboxylic dianhydride, 2,3,3′,4′-benzophenonetetracarboxylic dianhydride, Carboxylic acid dianhydrides containing aromatic rings such as diol bis (trimellitic dianhydride) such as ethylene glycol bis (trimellitic dianhydride), hexane glycol bis (trimellitic dianhydride), etc. 1,2 ,3,4-butanetetracarboxylic acid, 2,3,5-tricarboxycyclopentylacetic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentane Tetracarboxylic dianhydride, 1,2,3,5-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-bicyclohexanetetracarboxylic dianhydride, 1,2,4,5-cyclohexane Tetracarboxylic dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, meso-butane-1,2,3,4-tetracarboxylic Acid dianhydride, 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, 4-(2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic anhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, ethylenediamine tetracarboxylic anhydride Carboxylic dianhydrides containing aliphatic chains such as acetic dianhydride, diethylenetriaminepentaacetic dianhydride and the like.

Among them, from the viewpoint of reactivity, the compound (C) includes pyromellitic dianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride, 4,4′-oxydiphthalic anhydride, 3 ,3′,4,4′-biphenyltetracarboxylic dianhydride is preferred, is easily dissolved in the polysiloxane (A) and the polyalkylene glycol (B), and is homogeneous in the system, In addition, pyromellitic dianhydride is preferred because the reaction proceeds without using a metal catalyst as a reaction accelerator. These compounds (C) may be used alone or in combination of two or more.

The amount of the compound (C) having two carboxylic anhydride groups to be added is not particularly limited, but is preferably as small as possible so as not to affect the physical properties of the block copolymer of the present invention. The upper limit is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the block copolymer. By setting the addition amount of the compound (C) within this range, flexibility of the obtained block copolymer can be easily obtained, which is preferable. If the amount added is more than the above preferable range, the unreacted compound (C) tends to remain in the obtained polysiloxane copolymer, and the presence of the unreacted compound (C) causes the epoxy resin to It is not preferable because the curing reaction is accelerated, the fluidity is lowered, and the effect of improving the toughness is lowered.

(5) Method for producing a polyimide block copolymer The block copolymer of the present invention has (i) the polysiloxane (A), the polyalkylene glycol (B) and/or the two carboxylic anhydride groups. A step of reacting compound (C) to produce a polyamic acid block copolymer, which is a precursor of the polyimide block copolymer of the present invention, (ii) imide ring closure of the amic acid structure of the polyamic acid block copolymer It can be manufactured by the process of
As a reaction method in step (i), polysiloxane (A) and polyalkylene glycol (B) and/or a compound (C) having two carboxylic anhydride groups are mixed and heated to react. etc., and may be carried out in an organic solvent if necessary. Moreover, if necessary, the reaction may be carried out under a nitrogen atmosphere, or may be carried out under reduced pressure in order to promote the reaction.

In addition, the mixing ratio of polysiloxane (A), polyalkylene glycol (B) and divalent carboxylic acid anhydride (C) can be adjusted as appropriate. The equivalent ratio of the number of moles of the carboxylic acid anhydride groups to the total number of moles of the groups is preferably 0.2 to 5, more preferably 0.5 to 3, more preferably 0.8 to 1.5. 5 is most preferred, and 1 is highly preferred. When the equivalent ratio of the number of moles of the functional groups is within the above range, it is difficult for unreacted raw materials to remain in the polyamic acid block copolymer obtained in step (i), and the polyamic acid block copolymer has a high molecular weight. easy to convert.

In addition, since the precursor of the polyimide block copolymer of the present invention contains an amic acid structure generated by the reaction between an amino group and a carboxylic anhydride group, the reactive functional group of the raw material is an amino group and a carboxylic anhydride group. physical groups and may contain hydroxyl groups. Although the ratio of hydroxyl groups to amino groups can be adjusted as appropriate, the equivalent number of moles of hydroxyl groups to the number of moles of amino groups is 0.1-10. If there are too many amino groups, the flexibility of the block copolymer of the present invention tends to decrease. 0.5 or more is more preferable. Also, if the number of amino groups is too small, it becomes difficult to obtain high hydrolysis resistance derived from the amide bonds and imide bonds of the block copolymer of the present invention.

In order that the content of the structure derived from polysiloxane (A) contained in 100% by mass of the obtained block copolymer is 20% by mass or more and 90% by mass or less, the polysiloxane (A), the poly The total amount of the alkylene glycol (B) and/or the compound (C) having two carboxylic anhydride groups is 100% by mass, and the amount of the polysiloxane (A) is 20% by mass or more and 90% by mass or less. In addition, it is preferable to mix the raw materials and react them.

When an organic solvent is used for the reaction, the organic solvent is preferably a good solvent for polysiloxane (A) having a functional group and polyalkylene glycol (B) having a functional group. For example, hydrocarbon solvents such as toluene, xylene, benzene, and 2-methylnaphthalene; ester solvents such as ethyl acetate, methyl acetate, butyl acetate, butyl propionate, butyl butyrate, and ethyl acetoacetate; chloroform, bromoform, methylene chloride. , carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, chlorobenzene, 2,6-dichlorotoluene, 1,1,1,3,3,3-hexafluoroisopropanol and other halogenated hydrocarbons Solvent; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl butyl ketone; alcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol; N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide ( DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), propylene carbonate, trimethyl phosphate, 1,3-dimethyl-2-imidazolidinone, aprotic polar solvents such as sulfolane carboxylic acid solvents such as formic acid, acetic acid, propionic acid, butyric acid, and lactic acid; ether solvents such as anisole, diethyl ether, tetrahydrofuran, diisopropyl ether, dioxane, diglyme, and dimethoxyethane; 1-butyl-3-methylimidazolium acetate, ionic liquids such as 1-butyl-3-methylimidazolium hydrogen sulfate, 1-ethyl-3-imidazolium acetate, 1-ethyl-3-methylimidazolium thiocyanate; or mixtures thereof.

Among them, from the viewpoint that the polyimide block copolymer precursor generated by the reaction rate and reaction is easy to dissolve, N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethyl Acetamide (DMA) is preferred. Moreover, these organic solvents may be used alone or in combination of two or more.

However, if the organic solvent is not used, the purification process for removing the organic solvent is not required, the manufacturing process is simple, and the heat deterioration of the block copolymer due to the heating process for solvent removal is reduced. It is preferable from the viewpoint that it can be avoided. In particular, the polyimide block copolymer of the present invention has an aliphatic alkyl group in the molecule, but by using a method that does not use an organic solvent, thermal decomposition and oxidation due to heat treatment are less likely to occur, which is preferable.

The temperature at which the polysiloxane (A) having a functional group and the polyalkylene glycol (B) having a functional group are reacted is not particularly limited because it depends on the combination of the functional groups possessed by each, but suppresses side reactions and decomposition of the polymer. For this purpose, the temperature is preferably 220° C. or lower, more preferably 200° C. or lower, more preferably 180° C. or lower, and still more preferably 150° C. or lower. The lower limit of the reaction temperature is preferably 50° C. or higher, more preferably 70° C. or higher, and still more preferably 100° C. or higher.

In addition, a reaction accelerator or the like may be added during the reaction, but the functional group of polysiloxane (A) and the functional group of polyalkylene glycol (B) and / or the compound (C) having two acid anhydride groups Depending on the combination, it is possible to easily obtain the target block copolymer without adding a reaction accelerator. However, when a metal catalyst is used as a reaction accelerator, for example, when the obtained block copolymer is used as various additives such as semiconductor encapsulants, if the metal catalyst remains, the electrical properties may deteriorate. is not preferred because it may adversely affect Therefore, as described above, it is preferable to carry out the reaction without using a metal catalyst as a reaction accelerator.

The reaction time depends on the combination of the functional groups of the polysiloxane (A) and the polyalkylene glycol (B), but from the viewpoint of productivity, it is preferably within 20 hours, more preferably within 15 hours. , and more preferably within 10 hours.

In addition, as the imide ring-closing treatment in the step (ii), a generally known method can be used, and the precursor of the polyimide block copolymer obtained in the step (i) is heated to (1) 200 ° C. or higher. (2) heating in the presence of a small amount of an azeotropic solvent to azeotropically distill off the water produced; and (3) using a compound having a dehydrating action such as acetic anhydride. (1) The method of heating to 200 ° C. or higher requires a high temperature and is not economical, and the heat treatment easily causes thermal decomposition and oxidation of the aliphatic alkyl group structure in the block copolymer. ) and (3) are preferred, and the method (2) is particularly preferred from the viewpoint of ease of operation.

The azeotropic solvent used in the method (2) is not particularly limited, but organic solvents such as toluene, ethanol, ethyl acetate, hexane, cyclohexane, benzene and m-xylene can be used.

The heating temperature for imide ring closure is not particularly limited because it depends on the structure of the block copolymer, but is preferably 200° C. or less, more preferably 180° C., in order to suppress side reactions and decomposition of the polymer. °C or less is more preferable.
The reaction time for imide ring closure is not particularly limited because it depends on the structure of the block copolymer, but from the viewpoint of productivity, it is preferably within 20 hours, more preferably within 15 hours, and even more preferably within 15 hours. is within 10 hours.

(6) Epoxy resin composition The block copolymer of the present invention is produced by reacting two or more flexible polymers. And the effect of improving toughness can be expressed.

The epoxy resin composition of the present invention is a mixture of the epoxy resin described later and the block copolymer of the present invention, and refers to the mixture before curing reaction.

A preferable amount of the block copolymer contained in the epoxy resin composition of the present invention is 0.1 to 50 parts by mass, preferably 0.1 to 40 parts by mass, based on 100 parts by mass of the epoxy resin. , more preferably 0.5 to 30 parts by mass, more preferably 0.5 to 20 parts by mass. By including the block copolymer within this range in the epoxy resin composition, it is possible to efficiently relax the internal stress in the epoxy resin cured product obtained by curing the epoxy resin composition.

The epoxy resin is not particularly limited, but for example, a glycidyl ether type epoxy resin obtained from a compound having a hydroxyl group in the molecule and epichlorohydrin, a compound having an amino group in the molecule and epichlorohydrin. glycidylamine type epoxy resin, glycidyl ester type epoxy resin obtained from a compound having a carboxyl group in the molecule and epichlorohydrin, alicyclic epoxy resin obtained by oxidizing a compound having a double bond in the molecule, Alternatively, an epoxy resin or the like in which two or more types of groups selected from these are mixed in the molecule is used.

Specific examples of glycidyl ether type epoxy resins include bisphenol A type epoxy resin obtained by reaction of bisphenol A and epichlorohydrin, bisphenol F type epoxy resin obtained by reaction of bisphenol F and epichlorohydrin, 4, 4. Bisphenol S type epoxy resin obtained by reaction of '-dihydroxydiphenyl sulfone and epichlorohydrin, biphenyl type epoxy resin obtained by reaction of 4,4'-biphenol and epichlorohydrin, resorcinol and epichlorohydrin Resorcinol type epoxy resins obtained by reaction, phenol novolac type epoxy resins obtained by reaction of phenol and epichlorohydrin, other polyethylene glycol type epoxy resins, polypropylene glycol type epoxy resins, naphthalene type epoxy resins, and positional isomers thereof , an alkyl group, or a halogen-substituted product.

Commercially available bisphenol A epoxy resins include "jER" (registered trademark) 825, "jER" (registered trademark) 826, "jER" (registered trademark) 827, and "jER" (registered trademark) 828 (the above, Mitsubishi Chemical Co., Ltd.), "Epiclon" (registered trademark) 850 (manufactured by DIC Corporation), "Epotote" (registered trademark) YD-128 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), D.I. E. R-331™ (Dow Chemical Company), “Bakelite”™ EPR154, “Bakelite”™ EPR162, “Bakelite”™ EPR172, “Bakelite”™ EPR173, and "Bakelite" (registered trademark) EPR174 (manufactured by Bakelite AG) and the like.

Commercially available bisphenol F type epoxy resins include "jER" (registered trademark) 806, "jER" (registered trademark) 807, "jER" (registered trademark) 1750 (manufactured by Mitsubishi Chemical Corporation), "Epiclon ” (registered trademark) 830 (manufactured by DIC Corporation), “Epotato” (registered trademark) YD-170, “Epototo” (registered trademark) YD-175 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), “Bakelite” (registered Trademark) EPR169 (manufactured by Bakelite AG), "Araldite" (registered trademark) GY281, "Araldite" (registered trademark) GY282, and "Araldite" (registered trademark) GY285 (manufactured by Huntsman Advanced Materials), etc. is mentioned.

Commercial products of biphenyl-type epoxy resins include “jER” (registered trademark) YX4000, “jER” (registered trademark) YX4000K, “jER” (registered trademark) YX4000H, “jER” (registered trademark) YX4000HK, “jER” ( (Registered Trademark) YL6121H, "jER" (Registered Trademark) YL6121HN (manufactured by Mitsubishi Chemical Corporation), and the like.

Commercially available resorcinol epoxy resins include "Denacol" (registered trademark) EX-201 (manufactured by Nagase ChemteX Corporation).

Commercially available phenolic novolac epoxy resins include "jER" (registered trademark) 152, "jER" (registered trademark) 154 (manufactured by Mitsubishi Chemical Corporation), and "Epiclon" (registered trademark) 740 (DIC ( (manufactured by Huntsman Advanced Materials), EPN179, EPN180 (manufactured by Huntsman Advanced Materials).

Specific examples of glycidylamine type epoxy resins include tetraglycidyldiaminodiphenylmethanes, aminophenol glycidyl compounds, glycidylanilines, and xylenediamine glycidyl compounds.

Commercially available products of tetraglycidyldiaminodiphenylmethanes include "Sumiepoxy" (registered trademark) ELM434 (manufactured by Sumitomo Chemical Co., Ltd.), "Araldite" (registered trademark) MY720, "Araldite" (registered trademark) MY721, "Araldite" ( Registered trademark) MY9512, “Araldite” (registered trademark) MY9612, “Araldite” (registered trademark) MY9634, “Araldite” (registered trademark) MY9663 (manufactured by Huntsman Advanced Materials), “jER” (registered trademark) 604 (Mitsubishi Chemical Co., Ltd.), "Bakelite" (registered trademark) EPR494, "Bakelite" (registered trademark) EPR495, "Bakelite" (registered trademark) EPR496, and "Bakelite" (registered trademark) EPR497 (above, Bakelite manufactured by AG) and the like.

Commercially available glycidyl compounds of aminophenol include "jER" (registered trademark) 630 (manufactured by Mitsubishi Chemical Corporation), "Araldite" (registered trademark) MY0500, and "Araldite" (registered trademark) MY0510 (both from Huntsman Advanced Materials Co., Ltd.), “Sumiepoxy” (registered trademark) ELM120, and “Sumiepoxy” (registered trademark) ELM100 (both of which are manufactured by Sumitomo Chemical Co., Ltd.).

Commercially available glycidylanilines include GAN, GOT (manufactured by Nippon Kayaku Co., Ltd.) and "Bakelite" (registered trademark) EPR493 (manufactured by Bakelite AG).

Glycidyl compounds of xylenediamine include TETRAD-X (manufactured by Mitsubishi Gas Chemical Co., Ltd.).

Specific examples of the glycidyl ester type epoxy resin include diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl isophthalate, diglycidyl dimer and various isomers thereof.

Examples of commercially available diglycidyl phthalates include "Epomic" (registered trademark) R508 (manufactured by Mitsui Chemicals, Inc.) and "Denacol" (registered trademark) EX-721 (manufactured by Nagase ChemteX Corporation). be done.

Commercial products of diglycidyl hexahydrophthalate include "Epomic" R540 (manufactured by Mitsui Chemicals, Inc.) and AK-601 (manufactured by Nippon Kayaku Co., Ltd.).

Examples of commercial products of dimer acid diglycidyl ester include "jER" (registered trademark) 871 (manufactured by Mitsubishi Chemical Corporation) and "Epotato" (registered trademark) YD-171 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.). be done.

Commercially available alicyclic epoxy resins include "Celoxide" (registered trademark) 2021P (manufactured by Daicel Corporation), CY179 (manufactured by Huntsman Advanced Materials), and "Celoxide" (registered trademark) 2081 (manufactured by ) manufactured by Daicel), and “Celoxide” (registered trademark) 3000 (manufactured by Daicel Corporation).

As the epoxy resin, a resin selected from biphenyl type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin and bisphenol S type epoxy resin is preferable from the viewpoint of heat resistance, toughness and low reflow property, and biphenyl type epoxy resin. Alternatively, a bisphenol A type epoxy resin is more preferred, and a biphenyl type epoxy resin is even more preferred. The above epoxy resins may be used alone or in combination of two or more.

A curing agent and/or a curing accelerator can be added to the epoxy resin composition.

Epoxy resin curing agents include aliphatic polyamine-based curing agents such as diethylenetriamine and triethylenetriamine; alicyclic polyamine-based curing agents such as menzenediamine and isophoronediamine; and aromatic polyamine-based curing agents such as diaminodiphenylmethane and m-phenylenediamine. Curing agents; acid anhydride-based curing agents such as polyamide, modified polyamine, phthalic anhydride, pyromellitic anhydride and trimellitic anhydride; polyphenol-based curing agents such as phenol novolac resins and phenol aralkyl resins; polymercaptan, 2,4 , 6-tris(dimethylaminomethyl)phenol, anionic catalysts such as 2-ethyl-4-methylimidazole and 2-phenyl-4-methylimidazole; cationic catalysts such as boron trifluoride/monoethylamine complex; dicyandiamide, Examples include latent curing agents such as aromatic diazonium salts and molecular sieves.

A curing agent selected from an aromatic amine curing agent, an acid anhydride curing agent and a polyphenol curing agent is preferably used from the standpoint of providing an epoxy resin cured product having particularly excellent mechanical properties. A curing agent selected from phenol novolac resins and phenol aralkyl resins is particularly preferred because of its excellent storage stability.

Specific examples of the aromatic amine curing agent include metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, metaxylylenediamine, diphenyl-p-dianiline, various derivatives such as alkyl-substituted products thereof, and amino group-positioned curing agents. Different isomers are included.

Specific examples of acid anhydride curing agents include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, and tetrahydrophthalic anhydride. acids, hexahydrophthalic anhydride, dodecenyl succinic anhydride, benzophenonetetracarboxylic dianhydride, and the like.

Specific examples of polyphenol-based curing agents include phenol novolac resins, phenol aralkyl resins, 1-naphthol aralkyl resins, o-cresol novolac epoxy resins, dicyclopentadiene phenol resins, terpene phenol resins, and naphthol novolac type resins.

The optimum amount of the curing agent to be added varies depending on the type of epoxy resin and curing agent, but the stoichiometric equivalent ratio is 0.5 to 1.5 to the total epoxy groups contained in the epoxy resin composition. It is preferably between 4 and more preferably between 0.6 and 1.4. If the equivalent ratio is less than 0.5, the curing reaction may not occur sufficiently, resulting in poor curing or requiring a long time for the curing reaction. If the equivalence ratio is greater than 1.4, the curing agent that is not consumed during curing may become defective and degrade the mechanical properties.

The curing agent can be used in either monomer or oligomer form, and can be in powder or liquid form when mixed. These curing agents may be used alone or in combination of two or more. Moreover, you may use a hardening accelerator together.

Curing accelerators include amine compound curing accelerators typified by 1,8-diazabicyclo(5.4.0)undecene-7; imidazoles typified by 2-methylimidazole and 2-ethyl-4-methylimidazole. Compound-based curing accelerator: Phosphorus compound-based curing accelerator represented by triphenylphosphite, etc. can be used. Among them, the phosphorus compound-based curing accelerator is most preferred.

Various additives other than the epoxy resin and the block copolymer, such as flame retardants, fillers, colorants, release agents, and the like, may be added to the epoxy resin composition of the present invention, if necessary.

The filler is not particularly limited, but powders and fine particles of fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, silicon carbide, aluminum nitride, boron nitride, beryllia and zirconia are used. These fillers may be used alone or in combination of two or more. Among them, it is preferable to use fused silica because it lowers the coefficient of linear expansion. The shape of the filler is preferably spherical from the viewpoints of fluidity and wear resistance during molding.

The amount of the filler compounded is preferably 20 parts by mass to 2000 parts by mass, more preferably 50 to 2000 parts by mass, with respect to 100 parts by mass of the epoxy resin, from the viewpoint of lowering the moisture absorption rate, lowering the coefficient of linear expansion, and improving strength. parts, more preferably 100 to 2000 parts by mass, particularly preferably 100 to 1000 parts by mass, most preferably 500 to 800 parts by mass.

Examples of other additives include carbon black, calcium carbonate, titanium oxide, silica, aluminum hydroxide, glass fibers, hindered amine-based antidegradants, hindered phenol-based antidegradants, and the like.

These additives are preferably added before the epoxy resin composition is cured, and may be added in the form of powder, liquid, or slurry.

The epoxy resin composition of the present invention can be prepared by adding the block copolymer to an epoxy resin and/or a curing agent and kneading the mixture using a generally known kneader. Examples of kneaders include a three-roll kneader, a rotation-revolution mixer, and a planetary mixer.

The epoxy resin cured product of the present invention is obtained by subjecting the above epoxy resin composition to a curing reaction.

In order to advance the curing reaction for obtaining the epoxy resin cured product, temperature may be applied as necessary. The temperature at that time is preferably room temperature to 250°C, more preferably 50 to 200°C, even more preferably 70 to 190°C, and particularly preferably 100 to 180°C. Also, if necessary, a temperature raising program may be applied. The rate of temperature increase at that time is not particularly limited, but is preferably 0.5 to 20°C/min, more preferably 0.5 to 10°C/min, and still more preferably 1.0 to 5°C. / minutes.

The pressure during curing is preferably 1 to 100 kg/cm ² , more preferably 1 to 50 kg/cm ² , still more preferably 1 to 20 kg/cm ² , particularly preferably 1 to 5 kg/cm ² .

The semiconductor encapsulant of the present invention comprises the cured epoxy resin of the present invention. The epoxy resin cured product of the present invention is used as a suitable material for semiconductor encapsulants because the block copolymer dispersed therein acts as a stress reducing agent. The term "semiconductor encapsulating material" as used herein refers to a material for encapsulating electronic components such as semiconductor elements to protect them from external stimuli.

As described above, the block copolymer of the present invention has a repeating unit obtained from a precursor represented by any of the general formulas (1), (2) or (3) containing an imide bond, and has flexibility and epoxy properties. A multi-polyimide block copolymer that exhibits high dispersibility in resins and excellent hydrolysis resistance.

(n is 2 to 30, m is 5 to 100, p and r are 0 or 1; R ₁ is a linear or branched alkyl group having 2 to 10 carbon atoms; R ₂ is a hydrogen atom; an alkyl group or a phenyl group having a number of 1 to 5. R ₃ is selected from a divalent aliphatic or aromatic hydrocarbon group having 1 to 10 carbon atoms and a divalent hydrocarbon ether group having 1 to 10 carbon atoms. _R4 is a phenyl group, a biphenyl group, a diphenyl ether group, a benzophenone group, or a group having 40 or less carbon atoms composed of a linear, branched or cyclic aliphatic alkylene group. ₁ , R ₂ , R ₃ and R ₄ may be the same or different.)
In addition, the epoxy resin cured product obtained by curing the epoxy resin composition containing the block copolymer and the epoxy resin of the present invention suppresses bleeding out of the added block copolymer, and the elastic modulus of the epoxy resin cured product is lowered. In addition, the effect of improving toughness is also exhibited. For these reasons, the polyimide block copolymer of the present invention is also useful as various additives such as surfactants and resin modifiers, and is particularly suitable as a stress reducing agent for semiconductor encapsulants. .

EXAMPLES Next, the present invention will be described in more detail based on examples. The invention is not limited to these examples. The measurement methods used in the examples are as follows.

(1) Measurement of weight-average molecular weight The weight-average molecular weights of the polysiloxane (A) having a block copolymer and a functional group and the polyalkylene glycol (B) having a functional group were measured using gel permeation chromatography under the following conditions. and compared with a polymethyl methacrylate calibration curve to calculate the molecular weight.
Apparatus: Shimadzu Corporation LC-20AD series Column: Showa Denko KF-806L × 2
Flow rate: 1.0 mL/min
Mobile phase: Tetrahydrofuran Detection: Differential refractometer Column temperature: 40°C.

(2) Quantification of functional group content 0.5 g of the block copolymer is dissolved in 10 g of tetrahydrofuran and titrated with 0.1 mol/L alcoholic potassium hydroxide using phenolphthalein as an indicator to quantify the carboxylic acid content. did.

(3) Measurement of flexural modulus and strain at break A test piece was obtained by cutting the epoxy resin cured product in which the block copolymer was dispersed into a width of 10 mm, a length of 80 mm and a thickness of 4 mm. Using a Tensilon universal testing machine (TENSIRON TRG-1250, manufactured by A&D), according to JIS K7171 (2008), a three-point bending test was performed under the conditions of a distance between fulcrums of 64 mm and a test speed of 2 mm / min. Modulus and strain at break were measured. The measurement temperature was room temperature (23° C.), the number of measurements was n=5, and the average value was obtained.

(4) Method for confirming the presence or absence of bleeding out 10 g of cured epoxy resin in which the block copolymer is dispersed is immersed in 20 g of chloroform for one day, then the chloroform is separated and the solvent is removed by evaporation to dissolve in chloroform. The mass of the resulting block copolymer was measured. If the mass of the block copolymer dissolved in chloroform is 5% by mass or more relative to the mass of the block copolymer in the epoxy resin cured product calculated from the composition, there is bleeding out, and if it is less than 5% by mass It was evaluated as having no bleed out.

(5) Molecular weight reduction rate after adding water and heating To 1 g of block copolymer, 1 g of ion-exchanged water was added, and the mixture was heated to 100°C for 12 hours while stirring. After heating, the weight-average molecular weight of the polymer obtained by vacuum drying was measured by the method described in (1) above. The weight average molecular weights before and after the hydration/heat treatment were respectively defined as Mw (before) and Mw (after), and the molecular weight reduction rate was calculated by the following formula. The smaller the calculated molecular weight reduction rate, the better the hydrolysis resistance.
Molecular weight reduction rate (%) = 100-Mw (after) / Mw (before)

(6) Infrared absorption spectrum (confirmation of imide group formation)
The infrared absorption spectrum was measured under the following conditions.
A block copolymer was coated on a NaCl plate so as to have a film thickness of about 1 to 5 μm, and an infrared absorption spectrum was measured. The presence or absence of imide bond formation was confirmed from the peak near 1790 cm ⁻¹ derived from the imide bond in the obtained IR spectrum.
Apparatus: Shimadzu Corporation FT-IR IRPRESTIGE-21
Resolution: 2 cm ^-1
Accumulated times: 32 times

(7) ¹ H-NMR measurement (calculation of content of structure derived from polysiloxane (A))
It was measured using a nuclear magnetic resonance (NMR) apparatus (JNM-ECZ500R type) manufactured by JEOL Ltd. Heavy DMSO was used as the solvent.

[Production Example 1] (Polyimide Block Copolymer-1)
In a 200 mL two-neck flask, 10.0 g of maleic anhydride-modified silicone oil at both ends (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-168AS, weight average molecular weight 1000), amine-modified polypropylene glycol at both ends (Huntsman (Huntsman), 20.0 g of "JEFFAMINE" (registered trademark) D-2000, weight average molecular weight 2000) was added and nitrogen substitution was performed. Thereafter, the mixture was heated to 60° C. and reacted for 4 hours to obtain a block copolymer precursor as a yellow transparent liquid.

After adding 5 mL of toluene to 20 g of the obtained block copolymer precursor, the mixture was heated at 160° C. for 7 hours while distilling off the generated water to obtain a yellow transparent liquid. The resulting yellow transparent liquid was dried under reduced pressure at 80° C. for 12 hours to obtain a polyimide block copolymer-1. The resulting polyimide block copolymer-1 was a yellow transparent liquid, and the IR spectrum was measured to confirm absorption at 1790 cm ⁻¹ due to the imide group. The content of the structure derived from polysiloxane (A) was 33% by mass, the weight average molecular weight was 28,000, the carboxylic acid content was 0.21 mmol/g, and the molecular weight reduction rate after hydration and heating was 3%. rice field.

[Production Example 2] (Polyimide Block Copolymer-2)
In a 200 mL two-necked flask, 10.0 g of both terminal hydroxyl group-modified silicone oil (manufactured by Dow Toray Industries, BY16-201, weight average molecular weight 2000), both terminal amine-modified polypropylene glycol (Huntsman) 10.0 g of "JEFFAMINE" (registered trademark) D-2000, weight average molecular weight 2000) and 4.4 g of pyromellitic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and nitrogen substitution was performed. Thereafter, the mixture was heated to 100° C. and reacted for 2 hours, and further heated to 140° C. and reacted for 3 hours to obtain a block copolymer precursor as a yellow transparent liquid.

After adding 5 mL of toluene to 20 g of the obtained block copolymer precursor, the mixture was heated at 160° C. for 7 hours while distilling out the generated water to synthesize a yellow transparent liquid. The synthesized yellow transparent liquid was dried under reduced pressure at 80° C. for 12 hours to obtain a polyimide block copolymer-2. The obtained polyimide block copolymer-2 was a yellow transparent liquid, and when the IR spectrum was measured, absorption based on the imide group was confirmed at 1790 cm ⁻¹ . The content of the structure derived from polysiloxane (A) was 41% by mass, the weight average molecular weight was 23,000, and the carboxylic acid content was 0.50 mmol/g. The molecular weight reduction rate after adding water and heating was 2%.

[Production Example 3] (Polyimide Block Copolymer-3)
In a 200 mL two-neck flask, 15.0 g of both terminal hydroxyl group-modified silicone oil (manufactured by Dow Toray Industries, BY16-201, weight average molecular weight 2000), both terminal amine-modified polypropylene glycol (Huntsman) 5.0 g of "JEFFAMINE" (registered trademark) D-2000 (manufactured by Tokyo Chemical Industry Co., Ltd., weight average molecular weight 2000) and 4.4 g of pyromellitic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and nitrogen substitution was performed. Thereafter, the mixture was heated to 100° C. and reacted for 2 hours, and further heated to 140° C. and reacted for 3 hours to obtain a block copolymer precursor as a yellow transparent liquid.

After adding 5 mL of toluene to 20 g of the obtained block copolymer precursor, the mixture was heated at 160° C. for 7 hours while distilling out the generated water to synthesize a yellow transparent liquid. The synthesized yellow transparent liquid was dried under reduced pressure at 80° C. for 12 hours to obtain a polyimide block copolymer-3. The obtained polyimide block copolymer-3 was a yellow transparent liquid, and when the IR spectrum was measured, absorption based on the imide group was confirmed at 1790 cm ⁻¹ . The content of the structure derived from polysiloxane (A) was 60% by mass, the weight average molecular weight was 25,000, and the carboxylic acid content was 0.72 mmol/g. The molecular weight reduction rate after adding water and heating was 2%.

[Production Example 4] (Polyimide Block Copolymer-4)
In a 200 mL two-necked flask, 5.0 g of both terminal hydroxyl group-modified silicone oil (manufactured by Dow Toray Industries, BY16-201, weight average molecular weight 2000), both terminal amine-modified polypropylene glycol (Huntsman) 15.0 g of "JEFFAMINE" (registered trademark) D-2000, weight average molecular weight 2000) and 4.4 g of pyromellitic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and nitrogen substitution was performed. Thereafter, the mixture was heated to 100° C. and reacted for 2 hours, and further heated to 140° C. and reacted for 3 hours to obtain a block copolymer precursor as a yellow transparent liquid.

After adding 5 mL of toluene to 20 g of the obtained block copolymer precursor, the mixture was heated at 160° C. for 7 hours while distilling out the generated water to synthesize a yellow transparent liquid. The synthesized yellow transparent liquid was dried under reduced pressure at 80° C. for 12 hours to obtain a polyimide block copolymer-4. The obtained polyimide block copolymer-4 was a yellow transparent liquid, and when the IR spectrum was measured, absorption based on the imide group was confirmed at 1790 cm ⁻¹ . The content of the structure derived from polysiloxane (A) was 20% by mass, the weight average molecular weight was 21,000, and the carboxylic acid content was 0.21 mmol/g. The molecular weight reduction rate after adding water and heating was 1%.

[Production Example 5] (Polyimide Block Copolymer-5)
In a 200 mL two-neck flask, 17.5 g of both terminal amino group-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., silicone diamine KF-8010, weight average molecular weight 870), both terminal amine-modified polypropylene glycol glycol (Huntsman ( Huntsman), "JEFFAMINE" (registered trademark) D-2000), weight average molecular weight 2000) 0.4 g, pyromellitic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) 4.4 g was added, and nitrogen substitution was performed. gone. Thereafter, the mixture was heated to 100° C. and reacted for 2 hours, further heated to 140° C. and reacted for 4 hours to obtain a block copolymer precursor as a yellow transparent liquid.

After adding 5 mL of toluene to 20 g of the obtained block copolymer precursor, the mixture was heated at 160° C. for 7 hours while distilling out the generated water to synthesize a yellow transparent liquid. The synthesized yellow transparent liquid was dried under reduced pressure at 80° C. for 12 hours to obtain a polyimide block copolymer-5. The obtained polyimide block copolymer-5 was a yellow transparent liquid, and when the IR spectrum was measured, absorption based on the imide group was confirmed at 1790 cm ⁻¹ . The content of the structure derived from polysiloxane (A) was 73% by mass, the weight average molecular weight was 10,000, and the carboxylic acid content was 0.20 mmol/g. The molecular weight reduction rate after adding water and heating was 1%.

[Production Example 6] (Polyimide Block Copolymer-6)
In a 200 mL two-necked flask, 15.0 g of both terminal amino group-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., silicone diamine KF-8010, weight average molecular weight 870), polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd. , polypropylene glycol, diol type, 2000, weight average molecular weight 3350) and 4.4 g of pyromellitic dianhydride (manufactured by Tokyo Kasei Kogyo Co., Ltd.) were added to perform nitrogen substitution. Thereafter, the mixture was heated to 100° C. and reacted for 2 hours, further heated to 140° C. and reacted for 4 hours to obtain a block copolymer precursor as a yellow transparent liquid.

After adding 5 mL of toluene to 20 g of the obtained block copolymer precursor, the mixture was heated at 160° C. for 7 hours while distilling out the generated water to synthesize a yellow transparent liquid. The synthesized yellow transparent liquid was dried under reduced pressure at 80° C. for 12 hours to obtain a polyimide block copolymer-6. The obtained polyimide block copolymer-6 was a yellow transparent liquid, and when the IR spectrum was measured, absorption based on the imide group was confirmed at 1790 cm ⁻¹ . The content of the structure derived from polysiloxane (A) was 60% by mass, the weight average molecular weight was 26,000, and the carboxylic acid content was 0.71 mmol/g. The molecular weight reduction rate after adding water and heating was 1%.

[Production Example 7] (Copolymer-7)
In a 200 mL two-necked flask, 7.5 g of hydroxyl-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-6001, weight average molecular weight 3000), polypropylene glycol (manufactured by Wako Pure Chemical Industries, Ltd., polypropylene glycol , diol type, 2000, weight average molecular weight 3350) and 1.5 g of pyromellitic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and nitrogen substitution was performed. Thereafter, the mixture was heated to 160° C. and reacted for 8 hours to obtain Copolymer-7 as a colorless transparent liquid. The content of the structure derived from polysiloxane (A) was 50% by mass, the weight average molecular weight was 106,000, and the carboxylic acid content was 0.98 mmol/g. The molecular weight reduction rate after adding water and heating was 8%.

[Production Example 8] (Copolymer-8)
In a 200 mL two-necked flask, 4.0 g of both terminal amine-modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., silicone diamine KF-8010, weight average molecular weight 870), both terminal amine-modified polypropylene glycol (Huntsman ) company, “JEFFAMINE” (registered trademark) XTJ-542, weight average molecular weight 1000) 14.0 g, 3,3′,4,4′-diphenylsulfonetetracarboxylic dianhydride (manufactured by Tokyo Chemical Industry Co., Ltd. ) and 50 g of N-methyl-2-pyrrolidone were added to perform nitrogen substitution. After that, the mixture was heated to 180° C. and reacted for 5 hours while distilling out the generated water to obtain a reaction solution. The reaction solution was dried at 60° C. under reduced pressure for 12 hours to obtain a copolymer precursor. The content of the structure derived from polysiloxane (A) was 16% by mass, and the weight average molecular weight was 15,000.

After adding 2.5 mL of toluene to 10 g of the obtained copolymer precursor, dehydration was performed by heating at 160° C. for 7 hours to synthesize a yellow solid. The synthesized yellow solid was dried under reduced pressure at 80° C. for 12 hours to obtain a copolymer. The resulting copolymer was a yellow solid, and the IR spectrum was measured to confirm absorption at 1790 cm ⁻¹ due to the imide group. The resulting copolymer was insoluble in the solvent, and the carboxylic acid content and molecular weight reduction rate after adding water and heating could not be measured.

[Example 1] (Production of cured epoxy resin)
4.5 g of the block copolymer obtained in Production Example 1, 19.12 g of a biphenyl-type epoxy resin (manufactured by Mitsubishi Chemical Corporation, "jER" (registered trademark) YX4000H) as an epoxy resin, and a phenol novolak-type curing agent as a curing agent. (manufactured by Meiwa Kasei Co., Ltd., H-1) 10.88 g was weighed in a 150 cc stainless steel beaker and dissolved in an oven at 120° C. to homogenize. After that, 0.3 g of tetraphenylphosphonium tetra-p-tolyl borate as a curing accelerator and 80.5 g of silica spherical fine particles (HS-208, manufactured by Nippon Steel Chemical & Materials Co., Ltd.) as a reinforcing agent were added, and the mixture was easily cured with a stirring rod. After mixing, using a revolution mixer "Awatori Mixer" (manufactured by Thinky Co., Ltd.), mix once at 2000 rpm, 80 kPa, 1.5 minutes, stir once at 2000 rpm, 50 kPa, 1.5 minutes. The mixture was stirred twice at 2000 rpm and 0.2 kPa for 1.5 minutes to obtain an uncured epoxy resin composition.

This uncured epoxy resin composition was cast into an aluminum mold set with a 4 mm thick “Teflon” (registered trademark) spacer and a release film, and placed in an oven. The temperature of the oven was set to 80° C., held for 5 minutes, then heated to 175° C. at a rate of 1.5° C./min, and cured for 4 hours to obtain a cured epoxy resin having a thickness of 4 mm.

The obtained epoxy resin cured product was cut into a width of 10 mm and a length of 80 mm, and a Tensilon universal tester (TENSILON TRG-1250, manufactured by A&D) was used to measure 3 points according to JIS K7171 (2008). A bending test was performed to measure the bending elastic modulus and the breaking point strain. As a result of confirming the occurrence of bleed out, the soluble content was 0.1% and no bleed out occurred.

[Example 2] (Production of epoxy resin cured product-2)
A cured epoxy resin was obtained in the same manner as in Example 1, except that 4.5 g of the block copolymer obtained in Production Example 2 was added together with a curing accelerator.

The obtained epoxy resin cured product was cut into a width of 10 mm and a length of 80 mm, and a Tensilon universal tester (TENSILON TRG-1250, manufactured by A&D) was used to measure 3 points according to JIS K7171 (2008). A bending test was performed to measure the bending elastic modulus and the breaking point strain. As a result of confirming the occurrence of bleed out, the soluble content was 0.1% and no bleed out occurred.

[Example 3] (Production of epoxy resin cured product 3)
A cured epoxy resin was obtained in the same manner as in Example 1, except that 4.5 g of the block copolymer obtained in Production Example 3 was added together with a curing accelerator.
The flexural modulus and strain at break of the obtained cured epoxy resin were measured to find that the flexural modulus was 9.8 GPa and the strain at break was 2.9%. As a result of confirming the occurrence of bleed out, the soluble content was 0.1% and no bleed out occurred.

[Example 4] (Production of epoxy resin cured product 4)
A cured epoxy resin was obtained in the same manner as in Example 1, except that 4.5 g of the block copolymer obtained in Production Example 4 was added together with a curing accelerator.
The flexural modulus and strain at break of the obtained cured epoxy resin were measured to find that the flexural modulus was 9.5 GPa and the strain at break was 3.2%. As a result of confirming the occurrence of bleed out, the soluble content was 0.1% and no bleed out occurred.

[Example 5] (Production of epoxy resin cured product 5)
A cured epoxy resin was obtained in the same manner as in Example 1, except that 4.5 g of the block copolymer obtained in Production Example 5 was added together with a curing accelerator.
The flexural modulus and strain at break of the epoxy resin cured product obtained were measured to find that the flexural modulus was 9.8 GPa and the strain at break was 3.6%. As a result of confirming the occurrence of bleed out, the soluble content was 0.1% and no bleed out occurred.
[Example 6] (Production of epoxy resin cured product 6)
A cured epoxy resin was obtained in the same manner as in Example 1, except that 4.5 g of the block copolymer obtained in Production Example 6 was added together with a curing accelerator.
The flexural modulus and strain at break of the obtained cured epoxy resin were measured to find that the flexural modulus was 10.0 GPa and the strain at break was 3.6%. As a result of confirming the occurrence of bleed out, the soluble content was 0.1% and no bleed out occurred.

[Comparative Example 1]
A cured epoxy resin was obtained in the same manner as in Example 1, except that no copolymer was added.

Bleed-out did not occur, and the flexural modulus and strain at break of the obtained epoxy resin cured product were measured to find a flexural modulus of 13.1 GPa and a strain at break of 2.1%.

[Comparative Example 2]
A cured epoxy resin was obtained in the same manner as in Example 1, except that 4.5 g of the copolymer obtained in Production Example 7 was added together with a curing accelerator.

The flexural modulus and strain at break of the obtained cured epoxy resin were measured to find that the flexural modulus was 10.1 GPa and the strain at break was 3.2%. As a result of confirming the occurrence of bleed out, the soluble content was 0.1% and no bleed out occurred.

[Comparative Example 3]
Mixing was carried out in the same manner as in Example 1, except that 4.5 g of the copolymer obtained in Production Example 8 was added together with a curing accelerator. Therefore, a uniform epoxy resin cured product could not be obtained.

Production Examples 1 to 6 show that the polyimide block copolymers of the present invention are excellent in hydrolysis resistance. Further, by comparing Examples 1 to 6 with Comparative Examples 1 and 3, it was found that the cured product obtained by adding the block copolymer of the present invention had a reduced elastic modulus and excellent toughness. I understand.

Claims (9)

A polyimide block copolymer obtained from a copolymer precursor represented by any one of general formula (1), (2) or (3).

(n represents 2 to 30, m represents 5 to 100, p and r represent the number of repeating units of 0 or 1. R ₁ is a linear or branched alkyl group having 2 to 10 carbon atoms. R ₂ is is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a phenyl group, and R ₃ is a divalent aliphatic hydrocarbon group having 1 to 10 carbon atoms, an aromatic hydrocarbon group, or a divalent group having 1 to 10 carbon atoms. is a group selected from the hydrocarbon ether groups of R ₄ is a phenyl group, a biphenyl group, a diphenyl ether group, a benzophenone group, and a linear, branched or cyclic aliphatic alkylene group having 1 to 40 carbon atoms; A plurality of R ₁ , R ₂ , R ₃ and R ₄ may be the same or different.) 2. The polyimide block copolymer according to claim 1, which has a carboxyl group content of 0.1 mmol/g to 3.0 mmol/g and a weight average molecular weight of 5,000 to 100,000. 3. The polyimide block copolymer according to claim 1, which is obtained from a copolymer precursor in which R ₄ in any one of general formulas (1) to (3) is represented by a phenyl group. 4. The polyimide block copolymer according to any one of claims 1 to 3, obtained from a copolymer precursor in which p in general formula (1) or (2) is 0. The polyimide block copolymer according to any one of claims 1 to 4, wherein the structure derived from the siloxane block in the polyimide block copolymer is 20% by mass or more and 90% by mass or less. An epoxy resin composition comprising the polyimide block copolymer according to any one of claims 1 to 5. A cured epoxy resin obtained by curing the epoxy resin composition according to claim 6 . A semiconductor sealing material comprising the epoxy resin cured product according to claim 7 . The method for producing a polyimide block copolymer according to any one of claims 1 to 5, wherein the copolymer precursor represented by any one of the general formulas (1), (2) or (3) is subjected to dehydration ring closure.