JPH0582849B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Industrial Application Field The present invention relates to novel linear polyimide resins derived from tetracarboxylic acid anhydrides having an aliphatic structure and methods for producing them. More specifically, the present invention relates to a novel linear polyimide resin that has excellent heat resistance, transparency, chemical resistance, and adhesion to various substrates, and a method for producing the same. (b) Prior art Polyimide resin is a linear polymer obtained by the reaction of aromatic tetracarboxylic dianhydride such as pyromellitic dianhydride with aromatic diamine, and has high tensile strength and toughness. In addition to exhibiting excellent electrical insulation and chemical resistance, it also has excellent heat resistance. Therefore, it is suitable for use as heat-resistant films, adhesives, molding resins, laminating resins, and fibers.In recent years, these properties have been utilized to produce automobile parts, special mechanical parts, electrical and electronic materials, Applications to space and aircraft materials are becoming more popular. One of the external features of these heat-resistant aromatic polyimide resins is that they are colored a deep amber color. On the other hand, recently, a polyimide resin using a tetracarboxylic acid anhydride having an appropriate aliphatic structure and having excellent transparency and good heat resistance has been proposed (Japanese Patent Application Laid-open No. 6727-1989). However, the production of the raw material tetracarboxylic acid anhydride for this polyimide resin is relatively complicated;
This is not necessarily satisfactory in practice. (c) Problems to be Solved by the Invention The present invention solves the above-mentioned problems and provides a tetracarboxylic compound useful as a raw material for producing polyimide resins that are advantageous in industrial production and have excellent heat resistance, adhesion, and transparency. The present invention provides a novel polyimide resin having an aliphatic structure that is obtained from an acid anhydride and has excellent heat resistance, transparency, chemical resistance, and adhesion to various substrates, and a method for producing the same. (d) Means for Solving the Problems The present inventor has developed a method by polymerizing diphenoxyalkane-4,4'-bis(succinic anhydride) represented by the following general formula [] with an aromatic diamine. It has also been found that the polyimide resin obtained by subsequent dehydration and ring closure is transparent, tough, and has excellent heat resistance, chemical resistance, and adhesion to various substrates such as glass and metal. First, a method for producing diphenoxyalkane-4,4'-bis(succinic anhydride) used in the present invention will be described. General formula []

The method for producing diphenoxyalkane-4,4'-bis(succinic anhydride) represented by the following general formula []

4,4'-bis(β- ^cyano , β-alkoxy It can be produced by reacting carbonylvinyl)-diphenoxyalkane with alkali cyanide. In the above production method, the 4,4'-bis(β-cyano, β-alkoxycarbonylvinyl)-diphenoxyalkane represented by the general formula [] used as a starting material is represented by the general formula [] It can be produced by the reaction of 4,4'-diformyldiphenoxyalkane and cyanoacetic acid ester, and this reaction can be represented by the following formula.

[Chemical formula] (In the formula, n and R ² are the same as in the previous term) Here, 4,4'-bis(β-cyano, β-alkoxycarbonylvinyl) represented by the general formula []
-Diphenoxyalkanes can be produced by reacting p-hydroxyphenylaldehydes with methylene dihalides represented by the general formula []. This reaction can be expressed by the following formula.

[ka] (In the formula, X is halogen, n is the same as above)

[Formula] In the method for producing diphenoxyalkane-4,4'-bis(succinic anhydride) represented by the general formula [] above, alkali cyanide and 4,4' represented by the general formula [] It was found that the reaction of -bis(β-cyano, β-alkoxycarbonylvinyl)-diphenoxyalkane proceeded without a catalyst and an addition compound was produced. By acidically hydrolyzing this addition compound, diphenoxyalkane-4,4'-bis(succinic acid) represented by the general formula [] can be produced. This reaction can be expressed by the following formula.

[ka]

[Chemical formula] (In the formula, n and R ² are the same as above.) Diphenoxylated by boiling diphenoxyalkane-4,4'-bis(succinic acid) and acetic anhydride. Alkane-4,
4'-bis(succinic anhydride) can be produced.

embedded image (where n is the same as above) Next, the linear polyimide which is the object of the present invention will be described. The present invention first relates to a linear polyimide represented by the following repeating structural unit [ ].

(In the formula, n is an integer of 1 to 5, and R ¹ represents an aromatic diamine residue.) Furthermore, the present invention secondly provides the above repeating unit []
Regarding the manufacturing method of linear polyimide resin represented by
The manufacturing method is to polymerize diphenoxyalkane-4,4'-bis (succinic anhydride) represented by the general formula [] and aromatic diamine in a solvent, followed by dehydration and ring closure. The aromatic diamine to be reacted with diphenoxyalkane-4,4'-bis(succinic anhydride) is not particularly limited. Representative examples include p-phenylenediamine, m-phenylenediamine, diaminodiphenylmethane, diaminodiphenyl ether,
2,2-diaminodiphenylpropane, diaminophenyl sulfone, diaminobenzophenone, diaminonaphthalene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4' -di(4-aminophenoxy)diphenylsulfone, 2,2'-bis[4(4-aminophenoxy)phenyl]propane, and the like. These aromatic diamines are not limited to one type, and two or more types may be used. Furthermore, depending on the use of the polymide resin in the present invention, it is naturally preferable to select various aromatic diamines for the purpose of imparting specific properties, and for this purpose, some of the aromatic diamines are replaced with aliphatic diamines. , alicyclic diamine, etc. may be used without any problem. Furthermore, a portion of the diphenoxyalkane-4,4'-bis(succinic anhydride) may be added to other tetracarbons as long as the heat resistance, transparency, and adhesion to various substrates of the resulting polyimide resin are not impaired. Acid anhydrides, such as pyromellitic dianhydride,
There is no problem in using aromatic acid anhydrides such as benzophenonetetracarboxylic dianhydride, aliphatic acid anhydrides such as butanetetracarboxylic dianhydride, and the like. A polymerization method in which diphenoxyalkane-4,4'-bis (succinic anhydride) and aromatic diamine are polymerized in a solvent to form a so-called polyamic acid, which is then dehydrated and ring-closed to form a polyimide resin. This may be carried out in a one-step method in which a polyimide resin is obtained without isolating the polyamic acid, or in a two-step method in which the produced polyamic acid is isolated and then subjected to dehydration and ring closure to obtain a polyimide resin. The polymerization method used in the present invention is preferably a solution method. The solvent used in the solution method is not particularly limited as long as it dissolves the polyamic acid produced. Typical solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-
Methylpyrrolidone, N-methylcaprolactam,
Examples include dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethylphosphoramide, butyrolactone, and the like. These may be used alone or in combination. Furthermore, even if the solvent does not dissolve the polyamic acid, there is no problem in adding it to the above solvent as long as it can dissolve the polyamic acid. In the polymerization in the present invention, the molar ratio of diphenoxyalkane-4,4'-bis(succinic anhydride) to aromatic diamine is 0.5 to 2, preferably 0.9.
Any molar ratio between ~1.1 can be reacted.
As in normal polymerization reactions, the closer the molar ratio of these two components is to 1, the greater the molecular weight of the produced polyamic acid. The polymerization temperature for producing polyamic acid is −20~
Any temperature of 150℃ can be selected, especially from -5 to
A range of 100°C is preferred. In the present invention, in order to convert polyamic acid into polyimide resin, a method of dehydration and ring closure by heating is usually used. The temperature for this thermal dehydration ring closure can be selected from any temperature from 150 to 400°C, preferably from 170 to 350°C. The time required for this dehydration ring closure depends on the above reaction temperature, but is preferably 30 seconds to 10 hours, preferably 5 minutes to 5 hours.
It is appropriate to take your time. Further, as another method for converting polyamic acid into polyimide resin, a method of chemically ring-closing using a dehydration ring-closing catalyst can also be used. Regarding these methods, known methods used in the synthesis of ordinary polyimide resins can be used as they are, and the conditions are not particularly limited. (E) Effects of the invention Diphenoxyalkane-4 represented by the general formula [], which can be obtained relatively inexpensively by the method of the invention,
A polyimide resin obtained using 4'-bis(succinic anhydride) as one of the raw materials has not been known so far. Furthermore, the polyimide resin of the present invention has characteristics such as excellent transparency, heat resistance, and chemical resistance, and also excellent adhesion to various substrates such as glass and metal. Therefore, the polyimide resin of the present invention can be applied to display materials (for example, base films for transparent conductive films, liquid crystal alignment films), films, sheets, enamels, laminates, adhesives, laminating agents, and the like. (e) Examples The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. Examples 1 to 9 Production of polyamic acid and polyimide resin The reaction formula is shown below. The results are shown in Table 1.

[Chemical formula] (Y represents O, S, or CH ₂ as described in Table 1.)

[Chemical] 0.001 mol of diamine to 3.0 mol of dimethylacetamide
ml to make a homogeneous solution. Next, diphenoxyalkane-4,4'-bis(succinic anhydride) 0.001
mol was added little by little and allowed to react at room temperature for 24 hours. The reaction solution was cast on an aluminum sheet and dried under reduced pressure at 60 to 70°C for 4 hours to obtain a polyamic acid film. Furthermore, this film was heated at 220℃ under reduced pressure.
After heat treatment for 10 hours, the aluminum sheet was dissolved and removed with dilute hydrochloric acid to obtain a light yellow transparent polyimide resin film. Table 1 shows the measurement results of the reduced viscosity of the polyamic acid, the elemental analysis values of the polyimide resin, the thermal softening temperature, and the thermal stability. The measurement conditions are as follows. Polyamide acid reduced viscosity 0.2g/dl dimethylacetamide solution 30℃ Softening temperature Thermal stability 10% weight loss temperature of heating loss curve (heating rate 5℃/min) in air and nitrogen gas Figures 1, 2, 3, 4, 5, 6, 7, 8 and FIG. 9 show examples 1 (n=2, Y=O) and 2 (n=2, Y=
S), 3 (n=2, Y=CH ₂ ), 4 (n=3, Y=
O), 5 (n=3, Y=S), 6 (n=3, Y=
CH ₂ ), 7 (n = 4, Y = O), 8 (n = 4, Y =
Figure 3 shows charts of infrared absorption spectra (KBr tablet method) of polyimides of S) and Example 9 (n=4, Y= _CH2 ). The infrared absorption spectrum is 1770cm ^-1 and 1700cm
^-1 and 1290 cm ^{-1 ,} indicating that a 5-membered cyclic imide is produced. Moreover, Examples 1, 2,
The polyimide resins produced in Nos. 3, 4, 5, 6, 7, 8 and 9 are dimethylacetamide, N-methyl-
It was insoluble in 2-pyrrolidinone even when heated. Furthermore, FIGS. 13, 14, 15, 16, 17, 1
8, 19, 20 and 21, Examples 1, 2, 3,
4 shows heating loss curves of polyimide resins Nos. 4, 5, 6, 7, 8 and 9. The solid line is the measurement in air, and the dotted line is the measurement in nitrogen.

[Table] Reference Examples 1 to 3 Below, sialkane-4 used in the present invention,
An example of the production of 4'-bis(succinic anhydride) is shown for reference.

[ka]

[Chemical formula] 0.2 mol of 4,4'-bis(β-cyano, β-ethoxycarbonylvinyl)-diphenoxyalkane was dispersed in 1000 ml of ethanol, and 200 ml of an aqueous solution containing 42 g of potassium cyanide was added dropwise to the mixture at room temperature for 12 hours.
Stir for hours. After making the mixture strongly acidic with concentrated hydrochloric acid, ethanol and water were distilled off under reduced pressure using a rotary evaporator, 200 ml of concentrated hydrochloric acid was added to the residue, and the mixture was refluxed for 12 hours.
After cooling, the crystals were filtered off and recrystallized from a mixture of glacial acetic acid and water (9:1). 0.1 mol of this crystal was dispersed in 200 ml of acetic anhydride and refluxed for 4 hours.
Next, the product was allowed to cool to room temperature, the same volume of ethyl ether was added thereto, the product was filtered out, dissolved in heated acetic anhydride, and ethyl ether was added to crystallize the product.Diphenoxyalkane-4,4'- Bis(succinic anhydride)
I got it. Table 2 shows the yield, melting point, and elemental analysis values of the product. In addition, charts of infrared absorption spectra (KBr tablet method) corresponding to Reference Examples 1 (n = 2), 2 (n = 3) and Reference Example 3 (n = 4) are shown in Figures 10, 11 and 1.
Shown in 2.

【table】 [Brief explanation of the drawing]

Figures 1, 2, 3, 4, 5, 6, 7, 8 and 9 are
1 shows charts of infrared absorption spectra (KBr tablet method) of various polyimide resins produced in Examples 1, 2, 3, 4, 5, 6, 7, 8, and 9. Figures 10 and 11
and 12 show charts of infrared absorption spectra (KBr tablet method) of substituted diphenoxyalkane-4,4'-bis(succinic anhydride) of Reference Examples 1, 2, and 3. Also, Figures 13, 14, 15, 16, 1
7, 18, 19, 20 and 21 are Examples 1, 2,
Heating loss curves of various polyimides produced Nos. 3, 4, 5, 6, 7, 8, and 9 (solid lines are measurements in air, dotted lines are measurements in nitrogen, the vertical axis shows the weight remaining percentage, and the horizontal axis shows the temperature.

Claims (1)

[Scope of Claims] 1 The following structural unit [] [Chemical formula] (wherein, n is an integer of 1 to 5, and R ¹ represents an aromatic diamine residue), which is a precursor of polyamic acid A linear polyimide resin having a reduced viscosity of 0.1 to 2.0 dl/g (30°C, 0.2 g/dl dimethylacetamide solution). 2 Diphenoxyalkane-4,4'-bis(succinic anhydride) represented by the general formula [] [Chemical formula] (wherein n represents an integer of 1 to 5) and a diamine in a solvent. A repeating structural unit characterized by being polymerized and then subjected to dehydration ring closure [] [Chemical formula] (wherein n represents an integer of 1 to 5, and R ¹ represents an aromatic diamine residue) A method for producing linear polyimide resin.