JP4957583B2 - Solvent-soluble polyimide copolymer and polyimide varnish containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyimide copolymer having a high solvent solubility, an excellent balance of flexibility and flame retardance, a low coefficient of moisture absorption and suitably useful as electronic and electric component materials. <P>SOLUTION: The polyimide copolymer is obtained by subjecting a tetracarboxylic acid dianhydride mixture (A) containing a specific ester group-containing tetracarboxylic acid dianhydride and an aliphatic or alicyclic tetracarboxylic acid dianhydride and a diamine (B) containing a specific alkylene diamine and/or polyoxyalkylene diamine in the molar ratio of the component (A) to the component (B) in a range of (A):(B)=0.80-1.20 to imidation reaction. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a novel solvent-soluble polyimide copolymer and a polyimide varnish containing the same.

  In recent years, in the fields of electrical / electronic materials and optical materials, polyimide resin has been widely used as a resin that excels in heat resistance, stability, electrical properties, etc. due to the need for reduction in size, thickness, and weight. It is used for applications such as adhesion, insulation and protection of materials. The polyimide resin used in this application is usually supplied in the form of a varnish. Generally, it is roughly divided into two types: (i) a polyamic acid varnish which is a polyimide precursor, and (ii) a solvent-soluble polyimide varnish. Is done. In the former case, in order to obtain a cured product, it is necessary to perform solvent removal and imidization reaction. Therefore, a temperature of 300 ° C. or higher is necessary for the drying and curing treatment. Since there is a possibility of deterioration and damage, it is not preferable. Furthermore, the water generated during imidization causes defects in the polyimide cured product and causes voids, blisters, and gaps between the base material, causing adhesion failure and insulation failure. . On the other hand, in the latter case, since the imidization reaction is almost complete, a cured product can be obtained simply by volatilizing the solvent. Therefore, the treatment temperature can be lowered, and since there is no generation of water accompanying the imidization reaction, there is an advantage that a cured product with few defects is easily obtained.

  However, the conventionally known solvent-soluble polyimide resin has a rigid molecular chain, and thus has high heat resistance and low aqueous properties, but lacks flexibility and is inferior in flexibility and adhesion to a substrate is still insufficient. . In order to improve these performances, solvent-soluble polyimides using polysiloxane diamine as a diamine component have been proposed (Patent Documents 1 to 4). However, although this polyimide has improved flexibility and low water absorption, it has poor flame retardancy and has problems such as generation of siloxane-based outgas at high temperatures. Generation | occurrence | production of outgas causes a defect to a polyimide film, or causes the adhesiveness of a polyimide and a base material to fall. In addition, most of semiconductor components such as substrates are silicon-based inorganic materials, and siloxane-based outgas reacts easily with high affinity to these, causing a decrease in reliability as a semiconductor.

  Furthermore, polyimide varnish with a low solvent content, that is, a high polyimide resin concentration has been demanded in recent environmental awareness and demand for energy saving. However, if the concentration of the polyimide resin is increased, the stability of the varnish viscosity will deteriorate, causing problems such as precipitation during storage and increased viscosity, so that a polyimide varnish with a high polyimide resin concentration is obtained. Was difficult.

Japanese Patent Laid-Open No. 5-331285 Japanese Patent Laid-Open No. 9-40777 Japanese Patent Laid-Open No. 10-218993 JP 2000-103848 A

  An object of the present invention is to contain a polyimide copolymer that is highly soluble in a solvent, has a good balance between flexibility and flame retardancy, has a low water absorption rate, and does not substantially generate a siloxane-based outgas, and the polyimide copolymer. An object of the present invention is to provide a polyimide varnish and a polyimide molded body.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have obtained the following knowledge in the process of developing a polyimide copolymer.
(1) As a tetracarboxylic dianhydride component of a polyimide copolymer, the use of an ester group-containing tetracarboxylic dianhydride and an aliphatic or alicyclic tetracarboxylic dianhydride provides excellent flexibility. A polyimide copolymer having a low water absorption is obtained.
(2) By using an aliphatic diamine as the diamine component of the polyimide copolymer, the formation of a salt that inhibits the polymerization reaction is extremely small, and the polymerization becomes easy.
(3) The solvent solubility of polyimide that satisfies the requirements of (1) and (2) above is extremely high.
(4) A polyimide that satisfies the requirements of (1) and (2) above is excellent in flame retardancy.
(5) Furthermore, by copolymerizing a polyoxyalkylene diamine containing an ether group in the molecule as a diamine component, a more flexible polyimide copolymer can be obtained without impairing solvent solubility and flame retardancy. Be done.
This invention is completed based on the knowledge which concerns, and provides the polyimide copolymer and its polyimide varnish in the following items.

［式中、Ｘ^１は炭素数２〜１２の直鎖状若しくは分岐鎖状のアルキレン基、１，３−フェニレン基又は１，４−フェニレン基を表す。］
で表されるエステル基含有テトラカルボン酸二無水物（Ａ１）と炭素数８〜３０の脂肪族又は脂環族テトラカルボン酸二無水物（Ａ２）とを含むテトラカルボン酸二無水物混合物と、
（Ｂ）成分：
（i）炭素数２〜１８の直鎖状若しくは分岐鎖状のアルキレンジアミン（Ｂ１）を含むジアミン、又は、
（ii）炭素数２〜１８の直鎖状若しくは分岐鎖状のアルキレンジアミン（Ｂ１）と
一般式（２）

［式中、Ｒ^１、Ｒ^２及びＲ^３は、同一又は異なって、それぞれメチル基又は水素原子を表す。Ｘ^２は、炭素数２〜４の直鎖状若しくは分岐鎖状のアルキレン基を表す。ｈ、ｉ及びｊは、同一又は異なって、それぞれ０〜５０の整数を表し、且つ、ｈ＋ｉ＋ｊの合計が２〜５０の整数である。］
で表されるポリオキシアルキレンジアミン（Ｂ２）及び
一般式（３）

［式中、Ｘ^３は、炭素数２〜４の直鎖状若しくは分岐鎖状のアルキレン基を表す。ｋは１〜３０の整数である。］
で表されるポリオキシアルキレンジアミン（Ｂ３）からなる群より選ばれる少なくとも１種とを含むジアミンとを、
（Ａ）成分と（Ｂ）成分とのモル比を（Ａ）：（Ｂ）＝０．８０〜１．２０：１の範囲でイミド化反応に供して得られる溶剤可溶性ポリイミド共重合体。 (Item 1) Component (A):
General formula (1)

[Wherein, X ¹ represents a linear or branched alkylene group having ¹ to 12 carbon atoms, a 1,3-phenylene group, or a 1,4-phenylene group. ]
A tetracarboxylic dianhydride mixture containing an ester group-containing tetracarboxylic dianhydride (A1) and an aliphatic or alicyclic tetracarboxylic dianhydride (A2) having 8 to 30 carbon atoms,
(B) component:
(I) a diamine containing a linear or branched alkylene diamine (B1) having 2 to 18 carbon atoms, or
(Ii) C2-C18 linear or branched alkylenediamine (B1) and general formula (2)

[Wherein, R ¹ , R ² and R ³ are the same or different and each represents a methyl group or a hydrogen atom. X ² represents a linear or branched alkylene group having 2 to 4 carbon atoms. h, i, and j are the same or different and each represents an integer of 0 to 50, and the sum of h + i + j is an integer of 2 to 50. ]
The polyoxyalkylenediamine (B2) represented by the general formula (3)

Wherein, X ³ represents a linear or branched alkylene group having 2 to 4 carbon atoms. k is an integer of 1-30. ]
A diamine containing at least one selected from the group consisting of polyoxyalkylene diamines (B3) represented by:
A solvent-soluble polyimide copolymer obtained by subjecting the molar ratio of the component (A) to the component (B) in the range of (A) :( B) = 0.80 to 1.20: 1.

［式中、Ｘ^１は炭素数２〜１２の直鎖状若しくは分岐鎖状のアルキレン基、１，３−フェニレン基又は１，４−フェニレン基を表す。］
で表されるエステル基含有テトラカルボン酸二無水物（Ａ１）と炭素数８〜３０の脂肪族又は脂環族テトラカルボン酸二無水物（Ａ２）とを含むテトラカルボン酸二無水物混合物と、
（Ｂ）成分：
（i）炭素数２〜１８の直鎖状若しくは分岐鎖状のアルキレンジアミン（Ｂ１）を含むジアミン、又は、
（ii）炭素数２〜１８の直鎖状若しくは分岐鎖状のアルキレンジアミン（Ｂ１）と
一般式（２）

［式中、Ｒ^１、Ｒ^２及びＲ^３は、同一又は異なって、それぞれメチル基又は水素原子を表す。Ｘ^２は、炭素数２〜４の直鎖状若しくは分岐鎖状のアルキレン基を表す。ｈ、ｉ及びｊは、同一又は異なって、それぞれ０〜５０の整数を表し、且つ、ｈ＋ｉ＋ｊの合計が２〜５０の整数である。］
で表されるポリオキシアルキレンジアミン（Ｂ２）とを含むジアミンとを、
（Ａ）成分と（Ｂ）成分とのモル比を（Ａ）：（Ｂ）＝０．８０〜１．２０：１の範囲でイミド化反応に供して得られる、上記項１に記載の溶剤可溶性ポリイミド共重合体。 (Item 2) Component (A):
General formula (1)

[Wherein, X ¹ represents a linear or branched alkylene group having ¹ to 12 carbon atoms, a 1,3-phenylene group, or a 1,4-phenylene group. ]
A tetracarboxylic dianhydride mixture containing an ester group-containing tetracarboxylic dianhydride (A1) and an aliphatic or alicyclic tetracarboxylic dianhydride (A2) having 8 to 30 carbon atoms,
(B) component:
(I) a diamine containing a linear or branched alkylene diamine (B1) having 2 to 18 carbon atoms, or
(Ii) C2-C18 linear or branched alkylenediamine (B1) and general formula (2)

[Wherein, R ¹ , R ² and R ³ are the same or different and each represents a methyl group or a hydrogen atom. X ² represents a linear or branched alkylene group having 2 to 4 carbon atoms. h, i, and j are the same or different and each represents an integer of 0 to 50, and the sum of h + i + j is an integer of 2 to 50. ]
A diamine containing polyoxyalkylene diamine (B2) represented by:
Item 2. The solvent according to Item 1, obtained by subjecting the molar ratio of the component (A) to the component (B) in the range of (A) :( B) = 0.80 to 1.20: 1. Soluble polyimide copolymer.

(Claim 3) The above (B1) component is an alkylene diamine composed of a linear alkylene diamine (B1a) having 2 to 18 carbon atoms and a branched alkylene diamine (B1b) having 2 to 18 carbon atoms. Item 3. The solvent-soluble polyimide copolymer according to Item 1 or Item 2.

(Item 4) The solvent-soluble polyimide copolymer according to any one of Items 1 to 3, wherein the component (A2) is an alicyclic tetracarboxylic dianhydride having 10 to 18 carbon atoms.

［式中、Ｒ^４及びＲ^５は、同一又は異なって、それぞれ水素原子又はメチル基を表す。］
で表される脂環族テトラカルボン酸二無水物、
一般式（５）

［式中、Ｒ^６は水素原子又はメチル基を表す。］
で表される脂環族テトラカルボン酸二無水物、及び
一般式（６）

［式中、Ｒ^７は水素原子又はメチル基を表す。］
で表される脂環族テトラカルボン酸二無水物からなる群より選ばれる少なくとも１種（Ａ２ａ）であり、
（Ｂ１）成分が、炭素数２〜１８の直鎖状のアルキレンジアミン（Ｂ１ａ）と炭素数２〜１８の分岐鎖状のアルキレンジアミン（Ｂ１ｂ）とからなるアルキレンジアミンであり、
（Ｂ２）成分が、一般式（２）におけて、Ｘ^２が炭素数３又は４の直鎖状若しくは分岐鎖状のアルキレン基であり、ｈ＋ｉ＋ｊの合計が３〜３５の範囲であるポリオキシアルキレンジアミンである、上記項１〜４の何れかに記載の溶剤可溶性ポリイミド共重合体。 (Item 5) The component (A1) is an ester group-containing acid anhydride in which X ¹ in the general formula (1) is an ethylene group,
(A2) component is
General formula (4)

[Wherein, R ⁴ and R ⁵ are the same or different and each represents a hydrogen atom or a methyl group. ]
An alicyclic tetracarboxylic dianhydride represented by:
General formula (5)

[Wherein R ⁶ represents a hydrogen atom or a methyl group. ]
And an alicyclic tetracarboxylic dianhydride represented by the general formula (6)

[Wherein R ⁷ represents a hydrogen atom or a methyl group. ]
And at least one selected from the group consisting of alicyclic tetracarboxylic dianhydrides represented by (A2a),
The component (B1) is an alkylene diamine composed of a linear alkylene diamine (B1a) having 2 to 18 carbon atoms and a branched alkylene diamine (B1b) having 2 to 18 carbon atoms,
The component (B2) is a polyoxy compound in which, in the general formula (2), X ² is a linear or branched alkylene group having 3 or 4 carbon atoms, and the total of h + i + j is in the range of 3 to 35. Item 5. The solvent-soluble polyimide copolymer according to any one of Items 1 to 4, which is an alkylenediamine.

(Item 6) The component (A2a) is an alicyclic tetracarboxylic dianhydride represented by the general formula (4),
(B1b) The solvent-soluble polyimide copolymer of Item 5, wherein the component is at least one selected from the group consisting of 2,2,4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine Coalescence.

(Claim 7) The solvent-soluble polyimide copolymer according to any one of claims 1 to 6, wherein the water absorption of the polyimide copolymer is 1.5% by weight or less.

(Item 8) The glass transition temperature of the polyimide copolymer (the glass transition temperature is the maximum value of the loss tangent tan δ expressed by the ratio of the loss elastic modulus E ″ to the storage elastic modulus E ′ (E ″ / E ′)). 8.) The polyimide copolymer according to any one of Items 1 to 7, wherein the temperature is 100 ° C. or lower.

(Item 9) The solvent-soluble polyimide copolymer according to any one of Items 1 to 8, wherein the flame-out time of the polyimide copolymer is within 70 seconds.

(Item 10) A polyimide varnish containing the polyimide copolymer according to any one of Items 1 to 9 and an organic solvent.

(Item 11) The polyimide varnish according to Item 10, wherein the content of the polyimide copolymer is 1 to 120 parts by weight with respect to 100 parts by weight of the organic solvent.

(Item 12) Item 10 or Item 11, wherein the organic solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, methylpropylene glycol acetate and ethylene glycol monobutyl ether acetate. Polyimide varnish.

  In the present specification and claims, the number of moles of component (A) is the sum of the number of moles of component (A1) and the number of moles of component (A2). In addition, as the component (B), the number of moles when the component (B1) and the component (B2) are used in combination is the sum of the number of moles of the component (B1) and the number of moles of the component (B2). Furthermore, the number of moles when (B1a component) and (B1b component) are used in combination as the component (B1) is the sum of the component (B1a) and the component (B1b). Therefore, the molar ratio of the component (A) to the component (B) is the ratio between [(A1) component mole number + (A2) component mole number] and [(B1) component mole number + (B2) component mole number]. Refers to the ratio.

According to the present invention, the following excellent effects are exhibited.
(1) The polyimide copolymer obtained from the said (A) component and (B) component used by this invention is excellent in solvent solubility, the balance of a softness | flexibility and a flame retardance, and electrical insulation.
(2) The polyimide copolymer of the present invention has good water absorption resistance.
(3) When manufacturing a molded object from the polyimide copolymer of this invention, a siloxane system outgas does not generate | occur | produce substantially in an application | coating process or a drying process.
(4) When the component (B1) and the component (B2) are used in combination as the component (B), the flexibility of the polyimide copolymer is further improved.
(5) The polyimide varnish of the present invention is excellent in storage stability. Even when stored for a long period of time, precipitation of the present polyimide copolymer is suppressed, or gelation of the polyimide varnish is suppressed. Further, when the component (B1a) and the component (B1b) are used in combination as the component (B), the storage stability is further improved.
(6) The polyimide copolymer of the present invention has good heat resistance.

<Solvent-soluble polyimide copolymer>
In the presence of a reaction solvent, the polyimide copolymer of the present invention comprises a specific tetracarboxylic dianhydride mixture (A) and a specific diamine (B) at a specific charge ratio, preferably in an inert gas atmosphere. A solvent-soluble polyimide copolymer obtained by imidization reaction according to a conventional method while heating and stirring.
More specifically, the specific tetracarboxylic dianhydride mixture (A) is an ester group-containing tetracarboxylic dianhydride (A1) represented by the general formula (1) and a carbon number of 8 to 30. It means a tetracarboxylic dianhydride mixture containing an aliphatic or alicyclic tetracarboxylic dianhydride (A2).
The specific diamine (B) is (i) a diamine containing a linear or branched alkylene diamine (B1) having 2 to 18 carbon atoms, or (ii) the component (B1). It means a diamine containing polyoxyalkylene diamines represented by general formula (2) and / or general formula (3) (which are B2 and B3, respectively).
The specific charging ratio means that the molar ratio of the component (A) to the component (B) is in the range of (A) :( B) = 0.80-1.20: 1.
This polyimide copolymer has the basic structural unit (-[AB]-) of (A) component and (B) component, and each component is (A1) component, (A2) component, Since a plurality of components (B1), (B2) and (B3) are used, it is usually a random copolymer.
In the present specification and claims, the mixture means that during the imidation reaction, two components, for example, (A) component and (A1) component and (A2) component exist, It is not limited to mixing the two components in advance before being subjected to the imidization reaction.

[Tetracarboxylic dianhydride mixture: component (A)]
In producing the polyimide copolymer of the present invention, as the component (A), an ester group-containing tetracarboxylic dianhydride (A1) component and an aliphatic or alicyclic tetracarboxylic dianhydride having 8 to 30 carbon atoms are used. (A2) A component is used as an essential component.

The component (A1) is an ester group-containing tetracarboxylic dianhydride represented by the above general formula (1), and is not particularly limited, and commercially available products and those obtained by a conventionally known production method can also be used. X ¹ in the general formula (1) is a linear or branched alkylene group having ^{1 to} 12 carbon atoms, a 1,3-phenylene group or a 1,4-phenylene group, preferably 2 to 6 carbon atoms. A linear or branched alkylene group, more preferably a linear or branched alkylene group having 2 to 4 carbon atoms, particularly an ethylene group is recommended.
Specifically, 1,2-ethylene bis (anhydro trimellitate), 1,3-propylene bis (anhydro trimellitate), 1,4-tetramethylene bis (anhydro trimellitate), 1, 5-pentamethylene bis (anhydro trimellitate), 1,6-hexamethylene bis (anhydro trimellitate), 1,3-phenylene bis (anhydro trimellitate), 1,4-phenylene bis (an Hydrotrimellitate) and the like. Among these, 1,2-ethylenebis (anhydrotrimellitate) is recommended because it is particularly excellent in the balance between heat resistance and flexibility.
(A1) A component can be used for imidation reaction individually or in combination of 2 or more types.

The component (A2) is an aliphatic or alicyclic tetracarboxylic dianhydride having 8 to 30 carbon atoms, and is not particularly limited and may be a commercially available product or a product obtained by a conventionally known production method.
In the present specification and claims, an aliphatic tetracarboxylic dianhydride means an aliphatic carbon in which all carbon atoms to which four carboxyl groups are bonded are aliphatic carbons. Carboxylic dianhydride means that at least one carbon atom to which four carboxyl groups are bonded constitutes an alicyclic structure.
The number of carbon atoms in the component (A2) is the total number of carbon atoms including four carboxy groups.
Specific examples of the aliphatic tetracarboxylic dianhydride include 1,2,3,4-butanetetracarboxylic dianhydride and 1,2,4,5-pentanetetracarboxylic dianhydride.
Specific examples of the alicyclic tetracarboxylic dianhydride include 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride. Anhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 2,3,5-tricarboxycyclopentylacetic acid dianhydride, 3,5,6-tricarboxynorbonane-2-acetic acid dianhydride 1,2,4,5-cyclohexanetetracarboxylic dianhydride, 2,3,4,5-tetrahydrofurantetracarboxylic dianhydride, bicyclo [2,2,1] -heptane-2,3,5 , 6-tetracarboxylic dianhydride, bicyclo [2,2,2] -oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, etc., bicyclo [2,2,2]- Octene-2, 3, 5, 6 Tetracarboxylic dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 4- (2,5 -Dioxotetrahydrofuran-3-yl) -4-methyl-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -7-methyl-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuran-3-yl) -3-methylcyclohexane-1, -Dicarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuran-3-yl) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride and the like.

  Among the components (A2), an aliphatic or alicyclic tetracarboxylic dianhydride having 8 to 22 carbon atoms is preferable. From the viewpoint of heat resistance, alicyclic tetracarboxylic dianhydrides are preferable, and alicyclic tetracarboxylic dianhydrides having 10 to 18 carbon atoms are more preferable. Furthermore, from the viewpoint of balance between heat resistance and flexibility, the alicyclic tetracarboxylic dianhydrides represented by the above general formulas (4) to (6) are more preferable, and particularly represented by the general formula (4). Alicyclic tetracarboxylic dianhydrides are recommended.

Specific examples of the alicyclic tetracarboxylic dianhydrides represented by the general formulas (4) to (6) include 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3, 4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -4-methyl-1,2,3,4-tetrahydronaphthalene-1,2- Dicarboxylic dianhydride, 4- (2,5-dioxotetrahydrofuran-3-yl) -7-methyl-1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride, 5- ( 2,5-dioxotetrahydrofuran-3-yl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuran-3-yl) -3-methyl-3- Cyclohexe 1,2-dicarboxylic acid dianhydride.
As a commercial item of the alicyclic tetracarboxylic dianhydride, for example, “Rikacid TDA-100 (product name)” (4- (2,5-dioxotetrahydrofuran-3-yl) manufactured by Shin Nippon Rika Co., Ltd.) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride), “Epicron B-4400 (product name)” (5- (2,5-dioxotetrahydrofuran) manufactured by Dainippon Ink & Chemicals, Inc. -3-yl) -3-methyl-3-cyclohexene-1,2-dicarboxylic dianhydride) and the like.

  (A2) A component can be used for imidation reaction individually or in combination of 2 or more types.

  In the present specification and claims, the components (A1) and (A2) are described in the form of “tetracarboxylic dianhydride”, but instead of these, various derivatives thereof are used in the imidization reaction. Can be provided. For example, tetracarboxylic acid, which is a hydrous acid of the tetracarboxylic dianhydride, acid chloride of the tetracarboxylic acid, ester of the tetracarboxylic acid and a lower alcohol having 1 to 4 carbon atoms, and the like correspond to various derivatives. To do.

In the present invention, as long as the effects of the present invention are not impaired, a part of the component (A) can be replaced with another tetracarboxylic dianhydride.
Examples of other tetracarboxylic dianhydrides include aromatic tetracarboxylic dianhydrides. Specific examples include pyromellitic dianhydride, 4,4′-oxydiphthalic anhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetra. Carboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′- Dimethyldiphenylsilanetetracarboxylic dianhydride, 3,3 ′, 4,4′-tetraphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, 4,4 ′ -Bis (3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, 4,4'-bis (3,4-dicarboxyphenoxy) diphenylsulfone dianhydride, 4,4'-bis (3,4-di Carboxyphenoxy) di Phenylpropane dianhydride, 3,3 ′, 4,4′-perfluoroisopropylidenediphthalic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, bis (phthalic acid) Phenylphosphine oxide dianhydride, p-phenylene-bis (triphenylphthalic acid) dianhydride, bis (triphenylphthalic acid) -4,4′-diphenyl ether dianhydride, bis (triphenylphthalic acid) -4, 4'-diphenylmethane dianhydride etc. are mentioned.
When these other tetracarboxylic dianhydrides are used, the range is preferably 15 mol% or less, more preferably 10 mol% or less, and particularly preferably 5 mol% or less, based on the total number of tetracarboxylic dianhydrides. It is preferable that

[Diamine: component (B)]
In the production of the polyimide copolymer of the present invention, as the component (B), (i) a diamine containing a linear or branched alkylene diamine (B1) having 2 to 18 carbon atoms, or (ii) the At least one selected from the group consisting of the component (B1), the polyoxyalkylene diamine (B2) represented by the general formula (2) and the polyoxyalkylene diamine (B3) represented by the general formula (3); A diamine containing is used.

  The alkylene diamine according to the present invention comprises, as the component (B1), a linear alkylene diamine (B1a) having 2 to 18 carbon atoms and / or a branched alkylene diamine (B1b) having 2 to 18 carbon atoms. Specific examples are linear or branched diaminoethane, diaminopropane, diaminobutane, diaminopentane, diaminohexane, diaminoheptane, diaminooctane, diaminononane, diaminodecane, diaminoundecane, diaminododecane, diaminotridecane. Examples include decane, diaminotetradecane, diaminopentadecane, diaminohexadecane, diaminoheptadecane, and diaminooctadecane.

Specific examples of the component (B1a) include ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, and octamethylenediamine. Among these, from the viewpoint of the balance between flexibility and heat resistance, linear alkylene diamine having 8 to 12 carbon atoms is preferable, and decamethylene diamine is more preferable.
Specific examples of the component (B1b) include 2-methylpentamethylenediamine, 2-methyl-2,4-pentanediamine, 2,2-dimethylpropane-1,3-diamine, and 2,2,4-trimethylhexa. Examples include methylenediamine and 2,4,4-trimethylhexamethylenediamine. Among these, from the viewpoint of flexibility, a branched alkylenediamine having 6 to 10 carbon atoms, preferably 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine is more preferable. Recommended.
The combined use of the component (B1a) and the component (B1b) is a particularly preferable aspect in that the storage stability is further improved.

  (B1) A component can be used for imidation reaction individually or in combination of 2 or more types.

  The polyoxyalkylene diamine according to the present invention is at least one selected from the group consisting of the component (B2) and the component (B3).

In the component (B2), X ² in the general formula (2) is a linear or branched alkylene group having 2 to 4 carbon atoms, and a tetramethylene group is preferable from the viewpoint of flexibility.
Moreover, h, i, and j in General formula (2) are 0-50, respectively, Preferably it is an integer of 0-35, respectively, and the sum total of h + i + j is 2-50, Preferably 3-35 More preferably, it is an integer of 5 to 35. Within such a range, a significant difference is recognized particularly from the viewpoint of the balance between flexibility and heat resistance.
Specific examples of commercially available products of component (B2) include Jeffamine (English notation; JEFFAMIN) D-230, D-400, D-2000, XTJ00 (ED-) manufactured by Huntsman (English notation; manufactured by HUNTSMAN). 600), XTJ-502 (ED2003), EDR-148, XTJ-542, XTJ-533, XTJ-536 and the like.

In the component (B3), X ³ in the general formula (3) is a linear or branched alkylene group having 2 to 4 carbon atoms, and a tetramethylene group is preferable from the viewpoint of flexibility.
Moreover, k in General formula (3) is an integer of 1-30, Preferably it is an integer of 10-20.
Specific examples of the commercially available product (B3) include Elastomer 1000P manufactured by Ihara Chemical Industry Co., Ltd.

  When applying to the use for which the flexibility of a polyimide molded body is required, the aspect which uses (B2) component independently as a polyoxyalkylene diamine which concerns on this invention is more preferable.

  In the present specification and claims, the component (B) is described in the form of “diamine”, but an amino group is used instead of them for the purpose of improving reactivity and exhibiting the effects of the present invention. A compound obtained by converting a part or all of the above to an isocyanate group, a silylated compound, or the like can be used.

In the present invention, as long as the effects of the present invention are not impaired, a part of the component (B) can be replaced with another diamine component.
As another diamine component, the well-known diamine used in the said field | area can be used. For example, m-phenylenediamine, p-phenylenediamine, 4,4′-diaminobiphenyl, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxybenzene), 9,9- Bis (3-aminophenyl) fluorene, 9,9-bis (4-aminophenyl) fluorene, 4,4′-diamino-3,3′5,5′-tetramethyldiphenylmethane, 4,4′-diamino-3 , 3'5,5'-tetraethyldiphenylmethane, 4,4'-diamino-3,3'5,5'-tetrapropyldiphenylmethane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3 '-Diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiph Phenylsulfone, 4,4′-diaminodiphenyl sulfide, 3,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4 -Aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,3-bis (3-aminophenoxy) benzene and other aromatic diamines, 1,4-diaminocyclohexane, 4,4'-diamino Dicyclohexylmethane, 4,4′-diaminodicyclohexylethane, 4,4′-diaminodicyclohexylpropane, bisaminomethylcyclohexane, diaminobicyclo [2.2.1] heptane, bis (aminomethyl) -bicyclo [2.2.1 ] Aliphatic diamines such as heptane or aliphatic diamines containing alicyclic groups It is.
When these other diamine components are used, the amount used is preferably 15 mol% or less, more preferably 10 mol% or less, and particularly preferably 5 mol% or less of the total diamine components.

<Imidation reaction>
The polyimide copolymer of this invention can be manufactured from the said (A) component and (B) component according to a well-known method. For example, (i) a method in which the (A) component and the (B) component are heated, and the imidization reaction is performed while removing the generated water from the system, (ii) the polyamic acid of the (A) component and the (B) component And a method of chemically ring-closing using a compound having a dehydrating action such as acetic anhydride. In production, it is recommended to carry out in an inert gas atmosphere from the viewpoint of safety.

Of the above production methods, production method (i) is industrially preferred. As a preferable embodiment of the production method (i), for example, the component (A) and the component (B) are dissolved in a reaction solvent in the absence of a catalyst, and then heated to the reaction temperature of the imidization reaction, and then the reaction system is removed. Examples thereof include a method of performing the imidization reaction while removing generated water.
In order to efficiently remove the produced water from the reaction system, it is recommended to use a liquid or gas body accompanied with water. The accompanying liquid or gas body is generally referred to as a reflux liquid, an azeotropic agent, an accompanying agent, or an accompanying gas. Examples of the reflux liquid include aromatic hydrocarbons such as toluene, xylene, ethylbenzene, tetralin, and solvent naphtha, and alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, and trimethylcyclohexane. When the reflux liquid is used, the amount used is preferably 1 to 30% by weight, more preferably 5 to 20% by weight, based on the reaction solvent. The addition time is not particularly limited, and may be added to the reaction system from the time when the reaction solvent is charged, or may be added immediately before the imidization reaction. The liquid that accompanies water forms part of the reaction solvent, but is simply referred to as a reflux liquid for the purpose of use.

In the imidization reaction, the charged molar ratio of the component (A) and the component (B) which are reaction substrates at the start of the reaction is as follows.
The charged molar ratio of the component (A) to the component (B) is in the range of (A) :( B) = 0.80-1.20: 1. From the viewpoint of the storage stability of the polyimide varnish, the molar ratio of the component (A) to the component (B) is preferably (A) :( B) = 1.01-1.20: 1. In addition, from the viewpoint of mechanical properties of the obtained polyimide molded body, the molar ratio of the component (A) to the component (B) is in the range of (A) :( B) = 1.00-1.10: 1. preferable.
Although the preparation molar ratio of the component (A1) and the component (A2) is not particularly limited, (A1) :( A2) = 90: from the viewpoint of the flexibility of the obtained polyimide molded body and the storage stability of the polyimide varnish. A range of 10 to 10:90 is preferable, and a range of (A1) :( A2) = 75: 25 to 25:75 is more preferable.
In addition, when (B) component is used in combination with (B1) component and at least one (B2 · B3) selected from the group consisting of (B2) component and (B3) component (that is, ( In the case of embodiment ii), the charged molar ratio is not particularly limited, but preferably (B1) :( B2 · B3) = 99 from the viewpoint of the balance between flexibility and flame retardancy of the obtained polyimide molded body. : 1-35: 65, more preferably (B1) :( B2 · B3) = 95: 5-60: 40 is recommended.
In the component (B1), when the component (B1a) and the component (B1b) are used in combination, the charged molar ratio is not particularly limited, but from the viewpoint of flexibility of the obtained polyimide molded body, (B1a) :( The range of B1b) = 99: 1 to 35:65 is preferable, and the range of (B1a) :( B1b) = 75: 25 to 50:50 is more preferable from the viewpoint of flexibility and solvent solubility.
In the (B2 · B3) component, the charged molar ratio of the (B2) component and the (B3) component is preferably in the range of (B2) :( B3) component = 100: 0 to 50:50, more preferably 100: A range of 0-75: 25 is recommended.

  As the reaction solvent, an aprotic polar solvent is preferably used. Specifically, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, hexahexane Methyl phosphate triamide, 1,3-dimethylimidazolidone, diglyme, triglyme, cyclohexanone, cyclopentanone, γ-butyrolactone, methyl propylene glycol acetate, methyl ethylene glycol acetate, butyl propylene glycol acetate, methyl benzoate, ethyl benzoate, Isophorone, ethylene glycol diacetate, diethylene glycol butyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol diacetate, diethylene Recall ethyl ether acetate, dipropylene glycol methyl ether acetate and the like, they may be used alone or as a mixed system. Among these, N-methyl-2-pyrrolidone, γ-butyrolactone, methylpropylene glycol acetate, and ethylene glycol monobutyl ether acetate are preferable from the viewpoints of polymerizability and viscosity stability.

  The use amount of the reaction solvent is usually 100 to 1000% by weight, preferably 130 to 500% by weight, based on the total weight of the components (A) and (B) (total weight of the reaction substrate). The

  The reaction temperature of the imidization reaction is usually 100 to 250 ° C., more preferably 150 to 220 ° C., although it depends on the types of component (A) and component (B), the charged molar ratio thereof, and the like.

  Although reaction time is based also on the kind of (A) component or (B) component, those charged molar ratios, etc., 0.5 to 24 hours are preferable normally.

  The imidation rate in the imidization reaction is most preferably 100%. However, an effective imidation ratio from an industrial viewpoint is preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more.

  In addition, as long as the effects of the present invention are not impaired, known monofunctional acid anhydrides and monoamines used in this field are used in combination as end cap agents for the purpose of improving heat resistance, adhesion, and molecular weight control. can do. Specific examples of the end cap agent include phthalic anhydride, maleic anhydride, nadic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. for acid anhydrides, and aniline, methylaniline, allylamine, etc. for monoamines. The

  Thus, the reaction solution of the polyimide copolymer obtained by imidation reaction is a polyimide resin solution containing the polyimide copolymer of the present invention, and can be used as the polyimide varnish of the present invention. Further, when isolating the present polyimide copolymer from the resin solution, a method of removing the reaction solvent from the resin solution by a heating operation and / or a decompression operation or a method of reprecipitation by adding the resin solution to a poor solvent Etc. are exemplified.

<Polyimide varnish>
The polyimide varnish of the present invention contains the polyimide copolymer of the present invention and an organic solvent. The content of the polyimide copolymer is 1 to 120 parts by weight per 100 parts by weight of the organic solvent, and preferably 20 to 90 weights from the viewpoint of viscosity stability (storage stability) of the varnish and ease of handling. Parts, more preferably in the range of 40-80 parts by weight.

  As the polyimide varnish, a reaction solution obtained by imidization reaction can be used as the polyimide varnish of the present invention. Moreover, the reaction solvent used by imidation reaction can be substituted with a desired organic solvent to obtain a polyimide varnish, or the isolated polyimide copolymer can be dissolved in a desired organic solvent to obtain a polyimide varnish.

Examples of the organic solvent include the same organic solvents as those exemplified in the item of the reaction solvent.
Moreover, when it is desired to obtain a polyimide molded body in the form of a coating film or a film from the polyimide varnish, it is preferable to use an organic solvent having a low boiling point for the purpose of improving the drying efficiency in the drying step. Such low-boiling organic solvents include aromatic hydrocarbons such as toluene, xylene, and solvent naphtha, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and dimethylcyclohexane, propylene glycol monomethyl ether, or acetone, methyl ethyl ketone, and methyl isobutyl. Examples thereof include ketones such as ketones. When these low-boiling organic solvents are used, the amount used is recommended to be in the range of 1 to 30% by weight, preferably 5 to 20% by weight, based on the weight of the total organic solvent.

When an aprotic polar solvent is used as the organic solvent, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, sulfolane, hexamethylphosphoric triamide, 1,3 -Dimethylimidazolidone, diglyme, triglyme, cyclohexanone, cyclopentanone, γ-butyrolactone, methyl propylene glycol acetate, methyl ethylene glycol acetate, butyl propylene glycol acetate are recommended. These can be used alone or as a mixed system.
Among these, at least one selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, methylpropylene glycol acetate, and ethylene glycol monobutyl ether acetate is preferable from the viewpoint of viscosity stability and hygroscopicity of the polyimide varnish. In particular, a combination of at least one selected from the group consisting of N-methylpyrrolidone and γ-butyrolactone and ethylene glycol monobutyl ether acetate is recommended.

  To the polyimide varnish of the present invention, other components conventionally used in this field can be added as necessary within a range not impairing the effects of the present invention. Examples include polyester resins, other polyimide resins, polyamideimide resins, polymer compounds such as polyamide resins, flame retardants, antifoaming agents, and antioxidants.

Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, benzotriazole-based antioxidants, etc. Among them, the heat resistance (retention rate of elastic modulus after long-term heating) of the polyimide copolymer ) Is preferably used, and more preferably a phenolic antioxidant having 10 to 80 carbon atoms is recommended.
Specific examples of such phenolic compounds include 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, 4,4′-methylenebis (2,6-di-t -Butylphenol), 4,4-butylidenebis (3-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,2'-methylenebis (4-methyl- 6-t-butylphenol), 4,4'-isopropylidenebisphenol, 2,4-dimethyl-6-t-butylphenol, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6 -Tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, 2,2'-dihydroxy-3,3-di (α-methylcyclohexyl) -5,5'-dimethyldiphenylmethane, 2,2 '-Isobutylidenebis (4,6-dimethylphenol), 2,6-bis (2'-hydroxy-3'-tert-butyl-5'-methylbenzyl) -4-methylphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,5-di-t-amylhydroquinone, 2,5-di-t-butylhydroquinone, 1,4-dihydroxyanthraquinone, 3-t-butyl-4-hydroxyanisole, 2- t-butyl-4-hydroxyanisole, 2,4-dibenzoylresorcinol, 4-t-butylcacatechol, 2,6-di-t-butyl-4-ethylpheno 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,4,5-trihydroxybenzophenone, α-tocopherol, bis [2- (2 -Hydroxy-5-methyl-3-tert-butylbenzyl) -4-methyl-6-tert-butylphenyl] terephthalate, triethylene glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) ) Propionate], 1,6-hexanediol-bis [3- (3,5-di-tert-butyl 4-hydroxyphenyl) propionate] and the like. Among these, 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, 4,4′-methylenebis (2,6-di-t-butylphenol), 4,4-butylidenebis (3-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 4, 4′-isopropylidenebisphenol, 2,4-dimethyl-6-tert-butylphenol, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3 -Tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl- 4-hydroxybenzyl) benzene, 2,6-di-tert-butylphenol, bis [2- (2-hydroxy-5-methyl-3-tert-butylbenzyl) -4-methyl-6-tert-butylphenyl] terephthalate Triethylene glycol bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3- (3,5-di-t-butyl 4- Hydroxyphenyl) propionate] is preferred.

  Such antioxidants can be used alone or in admixture of two or more. When using antioxidant, the addition amount is 0.01-5 weight part with respect to 100 weight part of polyimide copolymers, Preferably the range of 0.1-2 weight part is recommended.

  The polyimide varnish thus obtained is excellent in storage stability and used for various purposes.

<Polyimide molded product>
The polyimide molded body according to the present invention is obtained from the polyimide varnish according to any one of Items 10 to 12 using a known molding method. Examples of the form of the polyimide molded body include a thin film, a coating film, a film form, and a sheet form, and the form is appropriately selected according to a desired application.

There is no restriction | limiting in particular as said shaping | molding method, The well-known method used in this field | area is applicable. For example, as a process of obtaining a thin film / coating-like polyimide molded body, usually, (1) coating process; the polyimide varnish of the present invention is coated or cast on an object to be coated (insulating paint, metal, plastic, etc.) Step, (2) Drying step; consisting of a step of drying the polyimide varnish. Moreover, as a process of obtaining a film-form / sheet-form polyimide molded body, usually, (1) coating process; a process of coating or casting the polyimide varnish of the present invention on a support (here, the support is a base material) ), (2) drying step; a step of drying the organic solvent from the polyimide varnish coated on the support to preferably 10% by weight or less (the standard of the degree of drying here is that the polyimide molded body is self-supporting) Or (3) peeling step; a step of peeling the polyimide molded body from the support; (4) a drying step; a step of drying the peeled polyimide molded body.
Furthermore, the polyimide copolymer of the present invention can be used as a base film for FPC or TAB, an adhesive film, a coating material for electric wires, and the like.

Although the physical property of a polyimide molded body is explained in full detail below, this is also description of the physical property of the polyimide copolymer of this invention.
The molecular weight of the polyimide molded body (polyimide copolymer) is not particularly limited, but is preferably 5,000 as the number average molecular weight from the viewpoint of the balance between solvent solubility, mechanical properties (particularly flexibility), and thermal characteristics. To 100,000, more preferably 8,000 to 50,000, especially 10,000 to 35,000, and the weight average molecular weight is preferably 10,000 to 200,000, more preferably 12,000 to A range of 100,000, in particular 20,000 to 100,000, more preferably 25,000 to 80,000 is recommended. The molecular weight is a value measured by the method described in the Examples section below.

  The glass transition temperature (Tg) of the polyimide molded body (polyimide copolymer) is preferably 100 ° C. or lower, more preferably in the range of 30 to 80 ° C., particularly 40 to 40 ° C. from the viewpoint of the balance between flexibility and heat resistance. A range of 70 ° C is recommended. When Tg is lower than 0 ° C., a tendency to be inferior in heat resistance is recognized, and when Tg is higher than 100 ° C., a tendency to be inferior in flexibility is recognized. In addition, Tg is a value measured by the method as described in the item of the below-mentioned Example.

  The elastic modulus of the polyimide molded body (polyimide copolymer) is preferably 0.3 to 2.5 GPa, more preferably 0.5 to 1.5 GPa from the viewpoint of flexibility.

  The water absorption of the polyimide molded body (polyimide copolymer) is preferably 1.5% by weight or less, and particularly preferably 1.2% by weight or less. The lower the water absorption, the better the whitening resistance and dimensional stability. In addition, a water absorption is a value measured by the method as described in the term of the below-mentioned Example.

  Many materials used for electrical and electronic parts are required to have flame retardance in order to ensure safety against fires. From such a viewpoint, the flame extinguishing time of the polyimide molded body (polyimide copolymer) is preferably within 70 seconds. In the case of 70 seconds or less, it is determined that the material is substantially flame retardant. The flame extinguishing time is a value measured by the method described in the Examples section described later.

  Since the polyimide molded body thus obtained has the above-mentioned excellent physical properties, it is useful in various fields such as electric and electronic fields.

  EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. In addition, the abbreviation of the compound in an Example and a comparative example and the evaluation method of each physical property are as follows.

1. Compound abbreviation (A1) component;
TMEG: 1,2-ethylenebis (anhydrotrimellitate) (trade name “Licacid TMEG-100”, manufactured by Shin Nippon Rika Co., Ltd.)
(A2) component;
TDA: 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dicarboxylic dianhydride (trade name “Licacid TDA-100”, New Japan (Rika)
(Other tetracarboxylic dianhydrides);
BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride PMDA: pyromellitic anhydride (B1a) component;
C10DA: decamethylenediamine C12DA: dodecamethylenediamine (B1b) component;
TMHDA: Mixture of 2,2,4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine (trade name “Trimethylenehexamethylenediamine”, manufactured by Tokyo Chemical Industry Co., Ltd.)
(B2) component;
XTJ-542: In the general formula (2), X ² is a tetramethylene group, R ^{1 to} R ³ are methyl groups, and a total of h + i + j is 14 polyoxyalkylenediamine (“Jefamine XTJ-542”, total amine value (109.8, manufactured by Huntsman)
D-400: a polyoxyalkylenediamine (trade name “Jefamine D” in which X ² is 1,2-propylene group, R ^{1 to} R ³ are methyl groups, and the total of h + i + j is 5 to 6 in the general formula (2) -400 ", total amine number 246.9, manufactured by Huntsman)
(B3) component;
Erasuma 1000P: In the general formula (3), ^{X 2} is a tetramethylene group, n = 10 to 20 in which polyoxyalkylene diamine (trade name "Erasuma 1000P", total amine value 90.4, manufactured by Ihara Chemical Industry Co., Ltd.)
The total amine value is expressed in terms of mg of potassium hydroxide equivalent to hydrochloric acid required to neutralize 1 g of the sample (standard oil analysis test method established by Japan Oil Chemical Association).
(Other diamines);
BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl] propane)
Reaction solvent / organic solvent;
NMP: N-methyl-2-pyrrolidone GBL: γ-butyrolactone

2. Evaluation method (1) Evaluation of solvent solubility Solvent solubility is evaluated by visually observing the state in the reaction system after completion of the imidization reaction. The criteria for the evaluation are as follows. On the basis of this criterion, ◯ is excellent in solvent solubility, and x is inferior in solvent solubility.
○: Neither generation of precipitate nor gelation of the reaction solution was observed.
Δ: Slight generation of precipitates or gelation of reaction solution was observed.
X: Generation of precipitates or gelation of the reaction solution was clearly observed.

(2) Evaluation of storage stability of polyimide varnish Storage stability is evaluated by visually observing a change in the appearance of a polyimide varnish in which a polyimide varnish having a resin concentration of 40% by weight is stored at 25 ° C. The criteria for the evaluation are as follows. According to this standard, ◎ is particularly excellent in storage stability, and × is inferior in storage stability. ○ and ◎ are evaluated as practical levels.
A: Generation of precipitates and varnish gelation were not observed for 4 months or more after the start of evaluation.
◯: Generation of precipitates and varnish gelation were not observed for 3 months or more after the start of evaluation.
Δ: Formation of precipitates or gelation of varnish was observed in less than 3 months after the start of evaluation.
X: Generation of precipitates or gelation of varnish was observed within 24 hours after the start of evaluation.

(3) Molecular Weight Measurement About 1 g of a polyimide copolymer reaction solution (polyimide varnish) is diluted with about 30 ml of dimethylformamide to prepare a sample solution for molecular weight measurement. The number average molecular weight (Mn) and weight average molecular weight (Mw) in terms of polyethylene oxide are determined under the following measurement conditions using gel permeation chromatography (GPC).
[Measurement condition]
Equipment: Shimadzu RID-6A
Column: Shodex GPC AD802-S, AD803-S, AD-804S and AD805S connected in series Column temperature: 40 ° C
Eluent: (10 mmol / L-lithium bromide + 10 mmol / L-phosphoric acid) / dimethylformamide Flow rate: 1.0 mL / min
Detector: RI

(4) Evaluation of flexibility Flexibility is evaluated using a glass transition temperature (° C). The lower the glass transition temperature (Tg), the higher the flexibility.
As a specific operation, a polyimide molded body is prepared by casting a polyimide varnish. Next, the glass transition temperature (° C.) of the molded product is obtained using a dynamic viscoelasticity measuring device under the following measurement conditions. For the glass transition temperature, the loss tangent tan δ represented by the ratio (E ″ / E ′) of the loss elastic modulus E ″ and the storage elastic modulus E ′ is measured, and the obtained peak tan δ is taken as the peak top (see FIG. 1). ).
[Measurement condition]
Apparatus: RHEOGEL-E4000 manufactured by UPM
Measurement conditions: Tensile mode Waveform: Sine wave Frequency: 10Hz
Temperature increase rate: 5 ° C / min

(5) Evaluation of electrical insulation Electrical insulation is evaluated by a volume resistivity (Ω · cm). The higher the resistance value, the higher the electrical insulation.
Specifically, a polyimide varnish was coated on a sheet of Teflon (registered trademark of DuPont, USA) and dried under reduced pressure at 120 ° C. for 1.5 hours, and a film-like polyimide having a thickness of about 50 μm. Create a compact. A test piece is prepared by cutting the film into 15 cm × 15 cm. Using a vibration capacity type electrometer TR8401, an insulation resistance measurement power supply TR300C and an insulation resistance meter TR43C manufactured by ADVANTEST, the volume specific resistance value of the test piece is measured under the conditions of an applied voltage of 500 V and 25 ° C. × 60% RH. taking measurement.

(6) Measurement of water absorption rate When the water absorption rate is 1.5% by weight or less, it is judged that the water absorption rate is low, and it is evaluated as a practical level.
Specifically, a polyimide varnish is applied onto a Teflon sheet and dried under reduced pressure at 120 ° C. for 1.5 hours to produce a film-like polyimide molded body having a thickness of about 50 μm. The weight of the film and W _1, the weight of the wiped film water droplets on the surface after immersion in distilled water for 24 hours at 25 ° C. and W _2, to calculate the water absorption according to the following calculation formula (1).
Water absorption rate (% by weight) = [(W ₂ −W ₁ ) / W ₁ ] × 100 (1)

(7) Evaluation of flame retardancy Flame retardance is evaluated with the extinction time (seconds). The criteria for the evaluation are as follows. According to this standard, ○ is flame retardant, and は is excellent as flame retardant. ◎ or ○ is judged to be practical.
A: Flame extinguishing time is within 70 seconds, and 55 mm or more above the sample remained unburned.
○: Flame extinguishing time extinguished within 70 seconds.
X: The flame extinguishing time exceeded 70 seconds.
Specifically, a polyimide varnish is applied onto a Teflon sheet and dried under reduced pressure at 120 ° C. for 1.5 hours to produce a film-like polyimide molded body having a thickness of about 50 μm. The extinction time of the film is measured according to ISO 6722 (Fire Propagation Test).

(8) Evaluation of heat resistance The heat resistance was evaluated by visually observing the warpage of the polyimide molded body and the state of peeling from Kapton (registered trademark of US DuPont). The criteria for the evaluation are as follows. According to this standard, ◎ is particularly excellent in heat resistance, and × is inferior in heat resistance. ○ and ◎ are evaluated as practical levels.
(Double-circle): The curvature of a polyimide molded object and peeling from a Kapton are not recognized.
◯: Almost no warpage of the polyimide molded body and no peeling from the Kapton.
Δ: Either warpage of the polyimide molded body or peeling from the kapton is slightly observed.
X: Warpage of the polyimide molded body or peeling from the Kapton is observed.
As a specific operation, a polyimide varnish is applied on Kapton and dried under reduced pressure at 120 ° C. for 1.5 hours to prepare a film-like polyimide molded body. The molded body is subjected to a heat test at 150 ° C. for 100 hours under test conditions.

(10) Resin concentration of polyimide varnish The resin concentration (% by weight) of the polyimide varnish is determined according to the following method. 10 mg of polyimide varnish is precisely weighed (to the second decimal place) and set in a TG-DTA device (device name manufactured by Seiko Instruments Inc .; EXSTAR6000, TG-DTA6200), and weight at 350 ° C. under the following measurement conditions. Measure. It calculates according to the following formula (2) using the obtained measured value.
Measurement conditions; heating rate: 5 ° C./min, circulating nitrogen amount: 100 ml / min, measurement start temperature: 30 ° C.
(a formula)
Resin concentration (% by weight) of polyimide varnish = (W ₁ / W ₀ ) × 100 (2)
W ₁ ; Weight of measurement sample at 350 ° C. (g)
W ₀ : Weight of measurement sample before starting measurement (g)
The resin concentration of the polyimide resin in the reaction solution at the end of imidization is also determined by the same measurement method.

[Example 1]
In a 500 ml four-necked flask equipped with a nitrogen inlet tube, a stirrer, a distillation outlet, and a thermometer, 116 g of NMP as a reaction solvent, 13 g of xylene as a reflux liquid, and 20.9 g (0.051 mol) of TMEG as a component (A) And TDA 15.3g (0.051mol) and C10DA 17.2g (0.100mol) were prepared as (B) component, and it heated up to 180 degreeC, stirring under nitrogen stream. While removing the produced water out of the system, the imidization reaction was performed at that temperature for 5 hours to obtain a reaction solution of the polyimide copolymer of the present invention (polyimide varnish of the present invention). The resin concentration of the reaction solution was about 40% by weight. This was adjusted with NMP to a resin concentration of 40%. Using the obtained polyimide varnish, test pieces, films, coating films and the like (polyimide molded bodies) used for evaluation of each physical property were prepared.

Using the polyimide varnish or the polyimide molding, the molecular weight, flexibility (glass transition temperature), electrical insulation (volume resistivity), water absorption, flame retardancy and heat resistance of the polyimide copolymer, and storage of the polyimide varnish. The stability was evaluated and the results are shown in Table 1. Further, no voids or blisters were visually observed during the process of producing the polyimide molded body.
A part of the resulting polyimide copolymer reaction solution was poured into methanol for reprecipitation. The reprecipitated polymer was dried at room temperature under reduced pressure, and the dried product was subjected to infrared absorption spectrum analysis. As a result, the characteristic absorption of the carbonyl group derived from the imide ring was confirmed at 1715 cm ⁻¹ and 1780 cm ⁻¹ . In the following Examples 2 to 16, the characteristic absorption of the carbonyl group derived from the imide ring was also confirmed.

[Examples 2 to 16]
The reaction solution of the polyimide copolymer of the present invention was carried out in the same manner as in Example 1 except that the composition / type / ratio of the reaction substrate and the type of reaction solvent were changed to those shown in Table 1 or Table 2, respectively. (Polyimide varnish of the present invention) was obtained. Using the obtained polyimide varnish, test pieces, films, coating films and the like (polyimide molded bodies) used for evaluation of each physical property were prepared.
The resin concentrations of the reaction solutions obtained in Examples 2 to 16 were all about 40% by weight. The resin concentration was adjusted to 40% with an organic solvent of the same kind and composition as each reaction solvent (in Examples 14 and 15, the concentration was adjusted using ethylene glycol monobutyl ether acetate).
In the process of preparing the polyimide molded bodies obtained in Examples 2 to 16, no voids or blisters were visually observed.
Using the polyimide varnish or the polyimide molding, the molecular weight, flexibility (glass transition temperature), electrical insulation (volume resistivity), water absorption, flame retardancy and heat resistance of the polyimide copolymer, and storage of the polyimide varnish. The stability was evaluated, and the results are shown in Table 1 and Table 2, respectively.

[Comparative Examples 1-5]
The reaction was performed in the same manner as in Example 1 except that the composition, type, and ratio of the reaction substrate and the type of reaction solvent were changed to those shown in Table 3, respectively. However, in any of the comparative examples, gelation occurred during the imidization reaction, making the reaction difficult. Therefore, each physical property could not be evaluated.

  From Examples 1 to 5 shown in Table 1, the polyimide copolymer obtained from the (A) component and the (B1) component according to the present invention is solvent-soluble and has low water absorption, flexibility and flame retardancy. It turns out that it is excellent. Moreover, the polyimide copolymer obtained by using together (B1) component and (B2) component as (B) component is flexible, without impairing various physical properties, such as a flame retardance, a water absorption rate, and electrical insulation. (For example, comparison between Example 5 and Example 6 and Example 7). Furthermore, from Examples 10 to 16 shown in Table 2, the storage stability is improved by using the (B1a) component and the (B1b) component according to the present invention in combination, and the low absorption rate, flexibility and flame retardancy are improved. It is clear that the excellent balance is also good.

  According to the present invention, the polyimide copolymer is highly soluble in a solvent, has an excellent balance between flexibility and flame retardancy, has a low water absorption, and does not substantially generate a siloxane-based outgas. Industrially useful as a useful material.

It is a measurement figure for demonstrating the measuring method of the glass transition temperature Tg (degreeC) which concerns on this invention.

Claims (12)

(A) component:
General formula (1)

[Wherein, X ¹ represents a linear or branched alkylene group having ¹ to 12 carbon atoms, a 1,3-phenylene group, or a 1,4-phenylene group. ]
A tetracarboxylic dianhydride mixture containing an ester group-containing tetracarboxylic dianhydride (A1) and an aliphatic or alicyclic tetracarboxylic dianhydride (A2) having 8 to 30 carbon atoms,
(B) component:
(I) a diamine containing a linear or branched alkylene diamine (B1) having 2 to 18 carbon atoms, or
(Ii) C2-C18 linear or branched alkylenediamine (B1) and general formula (2)

[Wherein, R ¹ , R ² and R ³ are the same or different and each represents a methyl group or a hydrogen atom. X ² represents a linear or branched alkylene group having 2 to 4 carbon atoms. h, i, and j are the same or different and each represents an integer of 0 to 50, and the sum of h + i + j is an integer of 2 to 50. ]
The polyoxyalkylenediamine (B2) represented by the general formula (3)

Wherein, X ³ represents a linear or branched alkylene group having 2 to 4 carbon atoms. k is an integer of 1-30. ]
A diamine containing at least one selected from the group consisting of polyoxyalkylene diamines (B3) represented by:
A solvent-soluble polyimide copolymer obtained by subjecting the molar ratio of the component (A) to the component (B) in the range of (A) :( B) = 0.80 to 1.20: 1. (A) component:
General formula (1)

[Wherein, X ¹ represents a linear or branched alkylene group having ¹ to 12 carbon atoms, a 1,3-phenylene group, or a 1,4-phenylene group. ]
A tetracarboxylic dianhydride mixture containing an ester group-containing tetracarboxylic dianhydride (A1) and an aliphatic or alicyclic tetracarboxylic dianhydride (A2) having 8 to 30 carbon atoms,
(B) component:
(I) a diamine containing a linear or branched alkylene diamine (B1) having 2 to 18 carbon atoms, or
(Ii) C2-C18 linear or branched alkylenediamine (B1) and general formula (2)

[Wherein, R ¹ , R ² and R ³ are the same or different and each represents a methyl group or a hydrogen atom. X ² represents a linear or branched alkylene group having 2 to 4 carbon atoms. h, i, and j are the same or different and each represents an integer of 0 to 50, and the sum of h + i + j is an integer of 2 to 50. ]
A diamine containing polyoxyalkylene diamine (B2) represented by:
The solvent according to claim 1, which is obtained by subjecting the molar ratio of the component (A) to the component (B) to an imidization reaction in the range of (A) :( B) = 0.80-1.20: 1. Soluble polyimide copolymer.   The component (B1) is an alkylene diamine composed of a linear alkylene diamine (B1a) having 2 to 18 carbon atoms and a branched alkylene diamine (B1b) having 2 to 18 carbon atoms. Item 3. A solvent-soluble polyimide copolymer according to Item 2.   The solvent-soluble polyimide copolymer according to any one of claims 1 to 3, wherein the component (A2) is an alicyclic tetracarboxylic dianhydride having 10 to 18 carbon atoms. The component (A1) is an ester group-containing acid anhydride in which X ¹ in the general formula (1) is an ethylene group,
(A2) component is
General formula (4)

[Wherein, R ⁴ and R ⁵ are the same or different and each represents a hydrogen atom or a methyl group. ]
An alicyclic tetracarboxylic dianhydride represented by:
General formula (5)

[Wherein R ⁶ represents a hydrogen atom or a methyl group. ]
And an alicyclic tetracarboxylic dianhydride represented by the general formula (6)

[Wherein R ⁷ represents a hydrogen atom or a methyl group. ]
Is at least one selected from the group consisting of alicyclic tetracarboxylic dianhydrides represented by (A2a),
The component (B1) is an alkylene diamine composed of a linear alkylene diamine (B1a) having 2 to 18 carbon atoms and a branched alkylene diamine (B1b) having 2 to 18 carbon atoms,
The component (B2) is a polyoxy compound in which, in the general formula (2), X ² is a linear or branched alkylene group having 3 or 4 carbon atoms, and the total of h + i + j is in the range of 3 to 35. The solvent-soluble polyimide copolymer according to any one of claims 1 to 4, which is an alkylene diamine. (A2a) component is an alicyclic tetracarboxylic dianhydride represented by the general formula (4),
The solvent-soluble polyimide co-polymer according to claim 5, wherein the component (B1b) is at least one selected from the group consisting of 2,2,4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine. Coalescence.   The solvent-soluble polyimide copolymer according to claim 1, wherein the polyimide copolymer has a water absorption of 1.5% by weight or less.   The glass transition temperature of the polyimide copolymer (the glass transition temperature is the maximum value of the loss tangent tan δ represented by the ratio (E ″ / E ′) of the loss elastic modulus E ″ to the storage elastic modulus E ′). The polyimide copolymer in any one of Claims 1-7 which is 100 degrees C or less.   The solvent-soluble polyimide copolymer according to any one of claims 1 to 8, wherein the flame extinguishing time of the polyimide copolymer is within 70 seconds.   A polyimide varnish containing the polyimide copolymer according to claim 1 and an organic solvent.   The polyimide varnish of Claim 10 whose content of a polyimide copolymer is 1-120 weight part with respect to 100 weight part of organic solvents.   The polyimide varnish according to claim 10 or 11, wherein the organic solvent is at least one selected from the group consisting of N-methyl-2-pyrrolidone, γ-butyrolactone, methylpropylene glycol acetate and ethylene glycol monobutyl ether acetate. .

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