JPH0790082A - Granule of polyamic acid, its mixture and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject granule for producing polyimide, excellent in solubility in organic solvents and hardly causing lowering of molecular weight by reacting a tetracarboxylic acid dianhydride with diamine, etc., having a siloxane bond in an inert solvent and then, removing the solvent. CONSTITUTION:A tetracarboxylic dianhydride (e.g. pyromellitic dianhydride) is made to react with a diamine having a siloxane bond [e.g. 1, 3-bis(3- aminopropyl)-tetramethyldisiloxanel or the diamine having the siloxane bond together with a diamine having no siloxane bond (e.g. diaminodiphenyl ether) in a solvent (e.g. tetrahydrofuran) which does not strongly interact with a polyamic aid having a siloxane bond on a main chain to afford a suspension of polyamidic acid of formula I (R<1> is a quadrivalent aromatic residue; R<2> is a divalent hydrocarbon residue containing a siloxane bond) or formula I and formula II (R<3> is a divalent aromatic residure) and then, the solvent is removed to provide the objective granule of polyamic acid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamic acid powder having a siloxane bond in the main chain, a mixture thereof, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, polyamic acid having a siloxane bond in the main chain is N, N-dimethylformamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide,
N-methylcaprolactam, dimethyl sulfoxide, N
It has been produced by a solution polymerization method in which a tetracarboxylic acid and a diamine are reacted at a low temperature in a so-called aprotic polar solvent such as -acetyl-2-pyrrolidone or N, N-dimethylacetamide. At this time, the aprotic polar solvent has a large dipole moment, a strong interaction with the polyamic acid as a solute, and a strong association with the polyamic acid, as described in the following documents ( J. Pol
ymer Sci. A-1, vol. 4, 2607 ~ 2616, 1966, ibid.
A, vol. 25, 2005-2020, 1987, same magazine A, vol. 25,
2479 ~ 2491, 1987, Proceedings of ANTEC '91, 1742 ~ 174
Page 5).

As described above, since the solvent and the solute are strongly associated with each other, when a polyamic acid, a polyimide molded product or a coating is obtained from the polyamic acid solution obtained by the low temperature solution polymerization method, the solvent should be removed. There was a problem that it was difficult. Further, in the solution of polyamic acid, there is also a problem that the hydrolysis of polyamic acid progresses due to the moisture absorption of the solvent and the degree of polymerization of polyamic acid decreases (J. Appl.
Polymer Sci, vol. 8, 1039-1051, 1964).

Therefore, in order to solve these problems,
The following references describe a method of producing a polyamic acid by carrying out a polymerization reaction using a solvent having a low boiling point such as tetrahydrofuran (THF) and capable of easily removing the solvent (Industrial Chemistry, Vol. 71). , No. 9, pp. 1559-1564,
1968, J. Appl. Polymer Sci., Vol. 11,609-627,19
67 years). In addition, the present applicant previously filed Japanese Patent Application No. 4-21368.
No. 9 proposes a granular material of aromatic polyamic acid having a sufficiently high degree of polymerization obtained by using a low boiling point solvent such as THF. However, a polyamic acid powder having a siloxane bond in the main chain has not been obtained here.

Further, Japanese Patent Publication No. 39-22196, Japanese Patent Publication No. 39-30060, and Japanese Unexamined Patent Publication No. 60-22142.
5, JP-A 61-234, JP-A 61-2
In Japanese Patent No. 50030 and Japanese Patent Laid-Open No. 2-18420,
It is disclosed that a polyimide powder is obtained by adding a poor solvent such as acetone or ethyl acetate and a ring-closing agent such as acetic anhydride or pyridine to an aprotic polar solution of a polyamic acid. However, in these polyimide powders, most of the repeating constitutional units are imidized, so even if it is attempted to directly mold these powders, the heat fluidity is extremely poor, and the dynamics of the resulting polyimide molded product. The physical characteristics were not satisfactory either. Further, the solubility in an organic solvent was extremely low, and a solution could not be obtained from this powder or granular material.

[0006]

SUMMARY OF THE INVENTION The first object of the present invention is to provide a polyamic acid powder having a siloxane bond in the main chain, which has good solubility in organic solvents, and secondly, a polyamide. Providing a mixture of polyamic acid powders having a siloxane bond in the main chain with a small decrease in the molecular weight of the acid, and third, polyamic acid powders having a siloxane bond in the main chain from which the solvent can be easily removed. It is to provide a method for manufacturing a body.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that an aromatic tetracarboxylic dianhydride is dissolved or suspended in a solvent that does not interact strongly with a polyamic acid. Then, a diamine having a siloxane bond or a diamine having a siloxane bond and an aromatic diamine are added and polymerized to obtain a suspension of an aromatic polyamic acid having a siloxane bond in the main chain. From this suspension, The solvent can be easily removed and can be recovered as a powder or granular material, and the powder or granular material was found to have excellent solubility in an organic solvent.
It was found that in the mixture of the granular particles of the aromatic polyamic acid having a siloxane bond in the main chain and the solvent that does not strongly interact with the aromatic polyamic acid, the decrease in the molecular weight of the aromatic polyamic acid is small. The present invention has been reached based on such knowledge.

That is, the gist of the present invention is, firstly, a polyamic acid powder having a siloxane bond in the main chain, and secondly, a polyamic acid powder having a siloxane bond in the main chain. A mixture of a polyamic acid comprising a solvent which does not strongly interact with a polyamic acid having a siloxane bond in the main chain, and thirdly, a tetracarboxylic acid in a solvent which does not strongly interact with a polyamic acid having a siloxane bond in the main chain. A dianhydride is reacted with a diamine having a siloxane bond or a diamine having a siloxane bond and a diamine having no siloxane bond to obtain a suspension of a polyamic acid having a siloxane bond in the main chain, and then removing the solvent. And a method for producing a polyamic acid powder or granular material.

The present invention will be described in detail below. In the present invention, the polyamic acid having a siloxane bond in the main chain is a polyimide having a siloxane bond in the main chain by ring closure by heating or a chemical action, and is 60 mol% or more, preferably 70 mol% of repeating units of a polymer chain. % Or more, and more preferably 80 mol% or more means an organic polymer having a polyimide structure. As a method of ring-closing, a conventionally known method such as a method by heating or a method using a ring-closing agent such as acetic anhydride or pyridine can be applied.

In the present invention, a preferable polyamic acid having a siloxane bond in the main chain is represented by the general formula (1),
Alternatively, a homopolymer or copolymer of a polyamic acid having the structural units represented by the general formulas (1) and (2) is preferable.

[0011]

[Chemical 1]

[0012]

[Chemical 2]

Here, R ₁ represents a tetravalent aromatic residue containing at least one carbon 6-membered ring, and two valences of the tetravalent are paired with each other and adjacent carbons in the carbon 6-membered ring are paired. Bound to an atom. Specific examples of R ₁ include the following.

[0014]

[Chemical 3]

Particularly, R ₁ is preferably the following.

[0016]

[Chemical 4]

R ₂ represents a divalent hydrocarbon residue having a siloxane bond as shown below.

[0018]

[Chemical 5]

Here, R ₄ represents a divalent hydrocarbon residue, and R ₅ represents an alkyl group having 1 to 3 carbon atoms or a phenyl group. n shows the integer of 1-30. The following may be mentioned as specific examples of R ₂ .

[0020]

[Chemical 6]

Particularly, R ₂ is preferably the following.

[0022]

[Chemical 7]

R ₃ represents a divalent aromatic residue having 1 to 4 carbon 6-membered rings. Specific examples of R ₃ include the following.

[0024]

[Chemical 8]

[0025]

[Chemical 9]

The following are particularly preferred as R ₃ .

[0027]

[Chemical 10]

The polyamic acid powder having a siloxane bond in the main chain of the present invention is obtained by reacting the tetracarboxylic dianhydride with a diamine in a solvent that does not interact strongly with the polyamic acid having a siloxane bond in the main chain. And a suspension is obtained, and then the solvent is removed. Here, the solvent that does not strongly interact with the polyamic acid having a siloxane bond in the main chain refers to a solvent that does not dissolve the polyamic acid having a siloxane bond in the main chain, and has a solubility of less than 1 g per 100 ml of the solvent.

Among the solvents which do not strongly interact with the polyamic acid having a siloxane bond in the main chain, preferred solvents are those which do not dissolve the polyamic acid but dissolve at least one of tetracarboxylic dianhydride and diamine. As specific examples of such a solvent, tetrahydrofuran (THF), dioxane, trioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, 2-methoxyethanol, 2-ethoxyethanol, 2- ( (Methoxymethoxy) ethoxyethanol, 2
-Isopropoxyethanol, 2-butoxyethanol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monoethyl ether, tetraethylene glycol, 1-methoxy-2-propanol, 1- Water-soluble ether compounds such as ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, polypropylene glycol, water-soluble compounds such as acetone, methyl ethyl ketone, methyl isobutyl ketone Ketone compound, toluene, benzene, o-xylene, m Xylene, p- xylene, 1,
2,3, -trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, 1,2,3-triethylbenzene, 1,2 ，
Aromatic hydrocarbons such as 4-triethylbenzene and 1,3,5-triethylbenzene are listed, and one kind or a mixed solvent of two or more kinds of these groups is used. Of these, THF, dioxane, acetone, and toluene are particularly preferable.

The polyamic acid powder having a siloxane bond in the main chain of the present invention is a suspension obtained by reacting the aromatic tetracarboxylic dianhydride with a diamine in a solvent that does not interact strongly with the polyamic acid. After the above is obtained, it is obtained by removing the solvent. The reaction temperature is -20 to 5
0 degreeC, especially 0-30 degreeC are preferable. At this time, the polyamic acid produced is not dissolved in the solvent used, but is in a suspended state in the solvent. Therefore, the solvent is removed by a usual method such as filtration and drying to remove the polyamic acid powder particles. Since the solvent used does not strongly interact with the polyamic acid, the solvent can be easily removed, and a polyamic acid powder or granule having a low solvent content can be obtained. In particular, when THF, dioxane, acetone or toluene having high volatility is used as the solvent, the drying can be easily performed. The weight average molecular weight of the polyamic acid in the obtained polyamic acid powder is 500.
0 or more is preferable and 10000 or more is more preferable. If the weight average molecular weight is less than 5,000, it is difficult to obtain a suspension and it is difficult to obtain a polyamic acid powder.

Further, when the polyamic acid powder is produced, the solvent is not completely removed, or the polyamic acid powder is mixed with a solvent which does not strongly interact with the polyamic acid again and stored in this state. Then, the decrease in the molecular weight of the polyamic acid is small and the stability over time is maintained. That is, in the mixture of the polyamic acid powder and the solvent which does not strongly interact with the polyamic acid, the decrease in the molecular weight of the polyamic acid powder is small. The polyamic acid powder in the present invention may have any shape such as spherical shape, irregular shape, and fibrous shape. It is preferable that the particle size of the particles is 500 μm or less and 80% by weight or more.

The polyamic acid powder obtained as described above can be used in various applications as a uniform solution by dissolving it in a solvent. As the solvent used for forming a uniform solution, a water-soluble ether compound, a water-soluble alcohol compound, a mixed solvent selected from water-soluble ketone compounds and water, or an ether group and an alcoholic hydroxyl group in the same molecule A single solvent of the compound can be mentioned as a preferable one. Further, an aprotic polar solvent generally used as a solvent for polyamic acid can also be used.

As a combination of mixed solvents for obtaining a uniform solvent, a combination of a water-soluble ether compound and water, a water-soluble ether compound and a water-soluble alcohol compound, and a water-soluble ketone compound and water are preferable. The mixing ratio of the solvent in the mixed solvent is 99.9: 0.1 to 65:35 in the case of a water-soluble ether compound and water, particularly 96: 4.
To 70:21 are preferable, and 99.9: 0.1 to 2 in the case of a water-soluble ether compound and a water-soluble alcohol compound.
5:75, particularly 90:10 to 56:44 are preferable, and 99.9: in the case of a combination of a water-soluble ketone compound and water.
0.1-40: 60, especially 90: 10-65: 35 (all are weight ratios) are preferable. Examples of the water-soluble ether compound include THF, dioxane, trioxane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, and the like, and THF is particularly preferable.

Examples of the water-soluble alcohol compound include methanol, ethanol, 1-propanol and 2-
Propanol, tert-butyl alcohol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentane All, 2-butene-1,4-diol, 2-methyl-2,4-pentanediol, glycerin, 2-ethyl-2-hydroxymethyl-1,3-propanediol,
1,2,6-hexanetoluol and the like can be mentioned, with particular preference given to methanol, ethanol and ethylene glycol. Examples of the water-soluble ketone compound include acetone and methyl ethyl ketone, with acetone being particularly preferred.

As a solvent having an ether group and an alcoholic hydroxyl group in the same molecule, 2-methoxyethanol,
2-ethoxyethanol, 2- (methoxymethoxy) ethoxyethanol, 2-isopropoxyethanol, 2
-Butoxyethanol, tetrahydrofurfuryl alcohol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monoethyl ether, tetraethylene glycol, 1-methoxy-2-propanol, 1-ethoxy -2-Propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, polyethylene glycol, polypropylene glycol and the like can be mentioned, among which 2-methoxyethanol, tetrahydrofurfuryl Alcohol is particularly preferred.

As the aprotic polar solvent, N, N-
Dimethylformamide, N-methyl-2-pyrrolidone,
Hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfoxide, N-acetyl-2-pyrrolidone, N, N-dimethylacetamide and the like can be mentioned.
By the way, a polyimide having a siloxane bond in its main chain is different from other polyimides, and depending on its composition, THF may be used.
It is known to dissolve in low boiling point solvents such as and dioxane. Therefore, since the polyimide powder obtained by heating or chemically treating the polyamic acid powder having a siloxane bond in the main chain of the present invention is also dissolved in the low boiling point solvent, it is used as a polyimide solution, and as a varnish or the like. It can be used and can be dried after application to form a film or film.

The polyamic acid powder having a siloxane bond in the main chain obtained in the present invention and the polyimide powder obtained by imidizing the polyamic acid are dissolved in a solvent to form a uniform solution. , Heat resistant insulation tape, heat resistant adhesive tape, high density magnetic recording base, capacitor,
Used in the manufacture of films for FPC. Also, for example, a sliding member filled with fluororesin or graphite,
It is used to manufacture molding materials and molded products such as structural members reinforced with glass fibers and carbon fibers, bobbins for small coils, sleeves, and tubes for terminal insulation. It is also used for manufacturing laminated materials such as insulating spacers for power transistors, magnetic head spacers, spacers for power relays, and spacers for transformers. It is also used for the insulation coating of electric wires and cables, solar cells, low temperature storage tanks, space insulation materials, integrated circuits, enamel for slot liners, and coating materials. Further, it is used for manufacturing ultrafiltration membranes, gas separation membranes and the like.

[0038]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto. The weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene. Also, the logarithmic viscosity (ηinh) is 30 ° C., and the concentration of the polyimide precursor is N-methyl-2-, which is 0.5 g / dl.
It was measured with a pyrrolidone (NMP) solution.

Example 1 Pyromellitic dianhydride (hereinafter PMDA) 2.181
g is dissolved in 50 ml of THF, and 0.099 g of 1,3-bis (3-aminopropyl) -tetramethyldisiloxane (hereinafter, APTMDS) and 1.922 g of diaminodiphenyl ether (hereinafter, DADE) are dissolved in 5 g thereof.
A diamine solution dissolved in 0 ml of THF was added at a temperature of 30
Gradually add not to exceed ℃, react for 60 minutes,
A suspension of polyamic acid having a siloxane bond in the main chain was obtained. This suspension was filtered to obtain a mixture of polyamic acid and THF. The Mw of this mixture is 1.22 × 1
It was 0 ⁵ . Further, this mixture was dried under reduced pressure to obtain a polyamic acid powder containing no solvent. At this time,
The Mw of the polyamic acid was 1.01 × 10 ⁵ . When this polyamic acid powder was dissolved in a mixed solvent of THF and methanol at a weight ratio of 6: 4, it was easily dissolved to obtain a yellow transparent solution.

Example 2 2.942 g of biphenyltetracarboxylic dianhydride (hereinafter, BPDA) as tetracarboxylic dianhydride, 0.087 g of APTMDS as diamine component, and DADE
Polymerization was performed in the same manner as in Example 1 except that 1.932 g was used to obtain a suspension. This suspension was filtered to obtain a mixture of polyamic acid and THF. The Mw of this mixture was 8.01 × 10 ⁴ . Further, this mixture was dried under reduced pressure to obtain a polyamic acid powder containing no solvent. At this time, the Mw of the polyamic acid was 6.70 × 10 ⁴ . When this polyamic acid powder was dissolved in a mixed solvent of THF and methanol at a weight ratio of 6: 4, it was easily dissolved to obtain a yellow transparent solution.

Example 3 1.2834 g of 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride (hereinafter referred to as BTDA) was dispersed in 30 ml of dry toluene. APTMDS 0.9
A solution prepared by dissolving 900 g in 25 ml of dry toluene was gradually added so that the temperature did not exceed 30 ° C., and reacted for 30 minutes to obtain a suspension of polyamic acid powder having a siloxane bond in the main chain. This suspension was filtered to take out powdery particles containing toluene. M of polyamic acid at this time
The w was 1.46 × 10 ⁴ . Further, it was dried under reduced pressure to obtain a polyamic acid powder containing no solvent. At this time, the Mw of the polyamic acid was 1.23 × 10 ⁴ . In addition, ηinh was 0.133.

Example 4 0.7919 g of APTMDS as a diamine component,
4,4'-diaminodiphenylmethane (DADM) 0.
Polymerization was performed in the same manner as in Example 3 except that 1579 g was used to obtain a polyamic acid powder. The Mw of the polyamic acid powder containing the solvent was 1.36 × 10 ⁴ , and the Mw after drying was 1.20 × 10 ⁴ . ηinh is 0.09
It was 2.

Example 5 2.578 g of BTDA was dispersed in 60 ml of dry toluene. APTMDS 0.994g, DADM
A solution prepared by dissolving 0.793 g in 50 ml of dry toluene was gradually added so that the temperature did not exceed 30 ° C., and reacted for 60 minutes to obtain a suspension of polyamic acid powdery particles having a siloxane bond in the main chain. . This suspension was filtered to take out powder and granules and dried under reduced pressure to obtain solvent-free polyamic acid powder and granules. The Mw of the obtained polyamic acid powder was 1.36 × 10 ⁴ . Also, ηinh is 0.092
Met.

[0044]

INDUSTRIAL APPLICABILITY The polyamic acid powder having a siloxane bond in the main chain of the present invention has a small residual solvent and excellent solubility in an organic solvent, and therefore can be used as a solution in various applications. Further, in the mixture of the polyamic acid powder particles having a siloxane bond in the main chain of the present invention, the decrease in the molecular weight of the polyamic acid is small. Further, according to the production method of the present invention, it is possible to easily produce a polyamic acid powder having a siloxane bond in the main chain, which has been difficult so far.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiaki Echigo 23 Uji Kozakura, Uji City, Kyoto Prefecture Unitika Ltd. Central Research Laboratory

Claims (3)

[Claims] 1. A powder of polyamic acid having a siloxane bond in the main chain. 2. A mixture of a polyamic acid comprising a polyamic acid powder having a siloxane bond in the main chain and a solvent which does not strongly interact with the polyamic acid having a siloxane bond in the main chain. 3. A tetracarboxylic dianhydride and a diamine having a siloxane bond or a diamine having a siloxane bond and a diamine having no siloxane bond are reacted in a solvent that does not strongly interact with a polyamic acid having a siloxane bond in the main chain. The method for producing a polyamic acid powder granule according to claim 1, wherein the solvent is removed after the suspension of the polyamic acid having a siloxane bond in the main chain is obtained.