JPH0153975B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat-resistant resin composition that has a high resin concentration, has good storage stability, and provides molded products such as coatings and films that have good heat resistance. It is well known that polyamide-imide resins have excellent heat resistance, chemical resistance, and mechanical properties, and are widely used in practical applications such as heat-resistant wire coatings, metal surface protection coatings, and films. However, this resin is generally soluble only in expensive and special solvents such as N-methyl-2-pyrrolidone and N,N-dimethylformamide, which makes the resin composition as a product expensive. In some cases, there may be restrictions on usage. If the amount of solvent that cannot be used as a coating film-forming component can be reduced and the resin concentration can be increased, substantial cost reductions can be achieved, and at the same time, it can also contribute to resource conservation. One method for increasing the resin concentration is to lower the molecular weight of the resin. Polyamide-imide resin compositions currently in practical use have a reduced viscosity of resin exceeding 0.4 and a resin concentration of 10 to 30% by weight.
(When the viscosity is 30±5 poise at 30°C). If the reduced viscosity is 0.4 or less, especially 0.35 or less, the resin concentration can be reduced to 35% by weight.
You can do more than that. However, if the molecular weight is simply lowered in this way, even though the resin concentration increases, the terminal functional group concentration of the resin increases, so the viscosity of the resin composition increases over time, and eventually gels. leading to. If the viscosity increases over time, for example, when used as a metal surface protection paint, the viscosity must be adjusted by changing the initially set coating conditions or diluting the thickened resin composition with a solvent. In addition, the properties of the protective coating formed by volatilizing the solvent may change. Particularly when applied to circuit boards for electronic components, it is necessary to form a film with a thickness of several microns, and viscosity change is a big problem. In order to improve such storage stability, a method has been proposed in which an alcohol is added and a heating reaction is caused to block the terminal groups. but,
The composition obtained by this method has a narrow baking range, and when applied to the production of enamelled wire, the flexibility and adhesion are significantly reduced, especially when the baking speed is slow, and the required performance as a product is not met. Therefore, it is necessary to pay close attention to controlling the furnace temperature and baking speed, and even then, defects may occur in some cases.
A serious problem arises in terms of practical productivity. One of the reasons for this is that alcohols that have reacted with terminal isocyanate groups are difficult to dissociate even at high temperatures.
It is thought that the molecular weight does not increase sufficiently during baking. As a result of various studies to solve this problem,
The present inventors have discovered that significant effects can be obtained by adding a very small amount of melamine or melamine derivatives, and have completed the present invention. That is, the present invention provides a heat-resistant resin having a reduced viscosity of 0.10 to 0.40 obtained by reacting a polyvalent isocyanate having two or more isocyanate groups in one molecule with a tribasic acid anhydride or a functional derivative thereof. After adding 0.1 to 10 parts by weight of alcohol to 100 parts by weight of resin and causing a heating reaction, heat-resistant resin
The present invention relates to a heat-resistant resin composition obtained by adding 0.01 to 5 parts by weight of melamine or a melamine derivative to 100 parts by weight and dissolving these in a solvent. In the production of heat-resistant resin in the present invention,
From the viewpoint of heat resistance, mechanical properties, chemical properties, etc., it is preferable to use the equivalent of the isocyanate group in a slight excess with respect to the sum of the equivalents of the carboxyl group and the acid anhydride group. Even if the addition reaction is carried out, the storage stability will be poor. Considering the balance between the two, it is preferable that the equivalent of the isocyanate group is 0.8 to 1.1 relative to the sum of the equivalents of the carboxyl group and the acid anhydride group. ,
It is more preferred to react in substantially equal equivalent ratios of 0.95 to 1.08. Polyvalent isocyanates having two or more isocyanate groups in one molecule include aliphatic, alicyclic,
Aroaliphatic, aromatic and heterocyclic polyisocyanates, such as ethylene diisocyanate, 1,4-
Tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, cyclobutene-1,3-diisocyanate, cyclohexane 1,3- and 1,
4-diisocyanate, isophorone diisocyanate 1,3 and 1,4-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanate and mixtures of these isomers, diphenylmethane-2,4'-diisocyanate, diphenylmethane- 4,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, xylylene diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methoxybenzene-2,4-diisocyanate, diphenyl diisocyanate Enylsulfone-4,4'-
Diisocyanates and compounds having three or more isocyanate groups in one molecule obtained by multiplying these diisocyanates, polyphenylmethylene polyisocyanates (for example, obtained by treating a condensate of aniline and formaldehyde with phosgene), etc. It can be used without any particular restriction. Examples of tribasic acid anhydrides include general formulas (i) and
A compound shown in (ii) is used. (X is _-CR2- (R is H or _CH3 ), -CO-, _SO2
-, -O-, etc.) Specific examples of compounds represented by the structural formula of formula (i) or formula (ii) include trimellitic anhydride, 2-(3,4
-dicarboxyphenyl)-2-(3-carboxyphenyl)propane anhydride, (3,4-dicarboxyphenyl)(3-carboxyphenyl)methane anhydride, (3,4-dicarboxyphenyl) )(3
-carboxyphenyl)ether anhydride, 3,
Examples include 3',4-tricarboxybenzophenone anhydride. In addition, 1,2,4-butanetricarboxylic anhydride, 2,3,5-naphthalenetricarboxylic anhydride, 2,3,6-naphthalenetricarboxylic anhydride, 1,2,4-naphthalenetricarboxylic anhydride, Examples include 2,2',3-biphenyltricarboxylic anhydride. From the viewpoint of heat resistance and cost, it is preferable to use trimellitic acid anhydride. If necessary, polybasic acids or functional derivatives thereof other than the above tribasic acid anhydrides or functional derivatives thereof can be used in combination. Examples of polybasic acids include tribasic acids such as trimesic acid and tris(2-carboxyethyl)isocyanurate, dibasic acids such as terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid;
2,3,4-butanetetracarboxylic acid, cyclopentanetetracarboxylic acid, ethylenetetracarboxylic acid, bicyclo-[2,2,2]-oct-(7)-ene-2:3,5:6-tetracarboxylic acid Aliphatic and alicyclic tetrabasic acids such as acids, pyromellitic acid,
3,3',4,4'-benzophenonetetracarboxylic acid, bis(3,4-dicarboxyphenyl)ether, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6 - naphthalenetetracarboxylic acid, ethylene glycol bistrimelitate,
2,2'-bis(3,4-dicarboxyphenyl)
Propane, 2,2',3,3'-diphenyltetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic acid, bis(3,4-dicarboxyphenyl)
Aromatic tetrabasic acids such as sulfone, bis(3,4-dicarboxyphenyl)methane, thiophene-
Examples include heterocyclic tetrabasic acids such as 2,3,4,5-tetracarboxylic acid and pyrazinetetracarboxylic acid. In the present invention, functional derivatives of tribasic acid anhydrides or functional derivatives of polybasic acids are monoanhydrides, dianhydrides derived from tribasic acid anhydrides or polybasic acids,
Means ester, amide, chloride, etc. When reacting a polyvalent isocyanate having two or more isocyanate groups in one molecule with a tribasic acid anhydride or its functional derivative and, if necessary, with a polybasic acid or its functional derivative, it must be carried out in an organic solvent. is preferred, and examples of organic solvents include N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphonamide, N-methyl-caprolactam,
Nitrobenzene, acetophenone, anisole, etc. are used. From the viewpoint of reactivity and performance of the resulting resin, it is preferable to use N-methyl-2-pyrrolidone as the synthesis solvent. The monomer concentration during synthesis is 40-80% by weight, especially 50-80% by weight.
It is preferable to carry out the reaction at 60% by weight. If the monomer concentration is less than 40% by weight, excess solvent must be evaporated after synthesis in order to obtain a composition with a high resin content, which is one of the objects of the present invention, which tends to be economically disadvantageous. Moreover, if it exceeds 80% by weight, the reaction tends to progress too quickly and become difficult to control. Here, the monomer concentration refers to the polyvalent isocyanate having two or more isocyanate groups in one molecule at the start of the reaction, the tribasic acid anhydride or its functional derivative, and the polybasic acid or its functional derivative used as necessary. The sum of the weights represents the weight fraction occupied in the system. The reduced viscosity of the resin obtained by reacting a polyvalent isocyanate having two or more isocyanate groups in one molecule with a tribasic acid anhydride or its functional derivative is 0.10 to 0.40, and can be 0.15 to 0.35. More preferred. If the reduced viscosity is less than 0.10, storage stability, heat resistance, and other practical performance will be insufficient.
If it exceeds 0.40, the resin concentration will decrease, making it impossible to satisfy one of the objects of the present invention. To adjust the reduced viscosity, prepare a calibration curve between the viscosity of the solution sampled from the reaction system (Gardner viscosity, absolute viscosity, etc.) and the reduced viscosity of the resin, and then measure the viscosity as appropriate during the reaction. can be done. Reduced viscosity is measured as follows. That is, 15 g of the resin solution (concentration approximately 10% by weight) immediately after synthesis is poured into water or methanol to form a precipitate.
Heat and dry at ℃ for 8 to 12 hours. Next, this solid resin was diluted with N,N-dimethylformamide to obtain a solution with a concentration of 0.5 g/dl, and the following was carried out using a conventional method.
Calculated by measuring the flow time using an Ostwald viscometer or Canon Fuenske viscometer at 30°C. If the reduced viscosity exceeds 0.40, the composition should be
Almost no change in viscosity is observed even after storage at 60°C for several months. On the other hand, if the reduced viscosity is set to 0.40 or less, especially if it is 0.35 or less, the viscosity increases or gels during storage as described above, causing a serious problem in practice. In order to solve such storage stability problems, it is extremely effective to add and react alcohols. At that time, simply adding and mixing alcohols does not improve the storage stability, and the temperature is preferably 40°C or higher, more preferably 50 to 150°C, even more preferably 80 to 120°C, and preferably 0.1 to 20 hours. , more preferably 0.5-10
It is necessary to carry out the heating reaction for a period of time, preferably 1 to 6 hours. The reason why storage stability is improved by addition of alcohol is not fully clear, but as shown in the following formula, the isocyanate group at the end of the molecular chain is blocked and stabilized by alcohol. It is. 〜〜〜(Resin)〜〜〜NCO+ROH→ 〜〜〜(Resin)〜〜〜NHCOORSimply adding and mixing alcohols at around room temperature does not improve storage stability, but the reason for this is that this terminal isocyanate This is thought to be because the groups are not sufficiently blocked. Furthermore, if the reaction is carried out at a mixed temperature or by heating for a longer time than necessary, heat resistance and other practical performance will deteriorate. One reason for this is that if the reaction is carried out at too high a temperature or for a long time, the amide and imide bonds in the molecular chain undergo an alcoholysis reaction with the alcohol, causing the bonds to cleave, as shown in the following formula. I wonder if there is. 〜〜〜CONH〜〜〜＋ROH→ 〜〜〜COOR＋H ₂ N〜〜〜 The amount of alcohol added is preferably 0.1 to 10 parts by weight, more preferably 100 parts by weight of the resin.
The amount is 0.5 to 5 parts by weight, more preferably 1 to 3 parts by weight. If it is less than 0.1 part by weight, the effect of improving storage stability is poor, and if it exceeds 10 parts by weight, practical properties such as heat resistance will deteriorate. Alcohols include methanol, ethanol, n-propanol, isopropanol, n-
Butanol, i-butanol, t-butanol,
Methyl cellosolve, ethyl cellosolve, methyl carbitol, benzyl alcohol, cyclohexynol, etc. are used. Among these, methanol, ethanol, propanol or butanol are effective. Melamine or a melamine derivative is added to the heat-resistant resin thus obtained, as described above. These melamines or melamine derivatives may be used alone or in combination. The amount of melamine or melamine derivative added is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 0.9 parts by weight, based on 100 parts by weight of the heat-resistant resin. As shown in the examples below, it is surprising that even addition of only about 0.2 part by weight can produce a remarkable effect. If the amount added exceeds 0.9 parts by weight, properties such as deterioration resistance and abrasion resistance tend to deteriorate when applied to enameled wire. The addition temperature is 30 to 100℃ to avoid side reactions.
is preferred. The melamine derivative used in the present invention has one melamine nucleus and one or more methylol groups in one molecule, and in some cases, the methylol group is etherified with an alcohol having 1 to 4 carbon atoms. Preferred compounds include monomethylolmelamine, dimethylol, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine, hexamethylolmelamine, etc., and all or part of the methylol groups of these compounds are methanol. Examples include those etherified with lower alkyl groups such as , ethanol, propanol, isopropanol, butanol, and isobutanol. As an example of a product, for example, ML- manufactured by Hitachi Chemical Co., Ltd.
520, ML-521, ML-243, etc. As a compound similar to the melamine derivative used in the present invention, there is a so-called melamine resin in which two or more melamine nuclei having one or more methylol groups are bonded by an ether bond, a methylene bond, etc.; Addition of a small amount of 1 part by weight or less has no effect, and conversely, it has a large negative effect of reducing deterioration resistance and wear resistance, so it cannot be used. Examples of solvents include those mentioned above as examples of solvents for synthesizing heat-resistant resins, as well as benzene, toluene, xylene, high-boiling aromatic hydrocarbons (for example, Nippon Oil's Hysol 100, Hysol 150, etc.),
In addition to γ-butyrolactone, polyhydric alcohol derivatives represented by the following general formula can be used. R ₃ COO (CHR ₄ CH ₂ O) _o H R ₃ COO (CHR ₄ CH ₂ O) _o COR ₅ R ₃ O (CHR ₄ CH ₂ O) _o R ₆ R ₃ O (CHR ₄ CH ₂ O) _o H R ₃ COO(CHR ₄ CH ₂ O) _o R ₇ (However, in the above formula, R ₃ , R ₅ , R ₆ , and R ₇ are lower alkyl groups, aryl groups, or aralkyl groups,
R ₄ is hydrogen or a methyl group, and n is an integer from 1 to 3. ) Specific examples of compounds represented by this general formula include ethylene glycol monoacetate, propylene glycol monoacetate, diethylene glycol monoacetate, ethylene glycol diacetate, propylene glycol diacetate,
Diethylene glycol diacetate, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether , ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether,
Diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monoisopropyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate , diethylene glycol monoisopropyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoisopropyl ether acetate, dipropylene glycol monomethyl ether acetate, and the like. Further, compounds represented by the following general formula can also be used. R ₁ OOC(CH ₂ ) _o COOR ₂ (However, in the above formula, R ₁ and R ₂ are lower alkyl groups, and n is an integer from 1 to 10.) Specific examples of compounds represented by this general formula include malon Dimethyl acid, diethyl malonate, diisopropyl malonate, dibutyl malonate, dibentyl malonate, dimethyl succinate, diethyl succinate, diisopropyl succinate, dibutyl succinate, dipentyl succinate, dimethyl glutarate,
Diethyl glutarate, dipropyl glutarate, dibutyl glutarate, dibentyl glutarate, dimethyl adipate, diethyl adipate, dipropyl adipate, dibutyl adipate, dipentyl adipate, dimethyl maleate, diethyl maleate, dipropyl maleate, maleic acid Examples include dibutyl, dipentyl maleate, dimethyl fumarate, diethyl fumarate, dipropyl fumarate, dibutyl fumarate, dipentyl fumarate, dimethyl pimelic acid, diethyl pimelic acid, and the like. The heat-resistant resin composition of the present invention has a solution viscosity of
When set at 25 to 30 poise (30℃), the resin concentration will be approximately 35 to 55% by weight, which is approximately 30% by weight of conventional products.
It is highly concentrated compared to The present invention will be explained in more detail below using Examples and Comparative Examples. Comparative Example 1 Diphenylmethane-4,4'-diisocyanate
1.67 kg of trimellitic anhydride, 1.28 kg of N-methyl-2-pyrrolidone, and 3.61 kg of N-methyl-2-pyrrolidone were placed in 10 synthesizers equipped with a thermometer, a stirrer, and a nitrogen inlet tube, and heated at 90°C.
The mixture was reacted for 1.5 hours, at 100°C for 1.5 hours, and at 120°C for 1.5 hours, and diluted by adding 1.45 kg of N,N-dimethylformamide. A small amount of this resin was sampled and the reduced viscosity of the resin was measured using the method described above, and the reduced viscosity was 0.31. Furthermore, add 46g of methanol and heat at 90°C.
The mixture was heated and reacted for an hour. The resulting composition had a resin concentration of 38.1% by weight and an initial viscosity of 33 poise, and the viscosity remained unchanged at 33 poise after being stored at room temperature for one month. Comparative Example 2 Methanol was not added to the heat-resistant resin synthesized in the same manner as in Comparative Example 1 and the reaction was not carried out, and the results were directly summarized in Table 1 below.
A final composition was prepared by adding the melamine derivative at the blending ratio shown in . The initial viscosity of the resulting composition was 33 poise, but it thickened after being stored at room temperature for one month.
It became 49 poise. Comparative Example 3 A final composition was prepared by adding a melamine derivative to the heat-resistant resin obtained in Comparative Example 1 at a blending ratio shown in Table 1 below. Examples 1 to 5 The heat-resistant resin obtained in Comparative Example 1 and melamine or various melamine derivatives were combined at the blending ratio shown in Table 1 to prepare a final composition. The composition of Example 1 was applied to a copper wire with a diameter of 1 mm by a conventional method so that the coating thickness was 40 μm, and the furnace temperature was 260/2.
The properties (measured according to JISC300) of the enamelled copper wire obtained by repeating coating and baking at 360/400°C (inlet/center/outlet) seven times were compared to Comparative Example 1,
Comparative example 3 and the characteristics of enamelled copper wire obtained in the same manner using a conventional commercially available polyamide-imide varnish (HL-405-30, manufactured by Hitachi Chemical Co., Ltd.) and different baking speeds are compared in the table below. Shown in 2. Furthermore, enamelled copper wires were obtained in the same manner using the compositions obtained in Examples 2 to 5, and the same tests were conducted, and the results are shown in Table 3.

【table】

【table】

[Table] Measure the length of minutes.

[Table] As described above, the heat-resistant resin composition of the present invention has excellent heat resistance, high resin concentration, good storage stability, and a wide range of baking operations. It can be widely applied industrially as surface protection paints, films, laminated products, adhesives, etc.

Claims (1)

[Claims] 1. Reduced viscosity obtained by reacting a polyvalent isocyanate having two or more isocyanate groups in one molecule with a tribasic acid anhydride or a functional derivative thereof.
Add 0.1 to 10 parts by weight of alcohol per 100 parts by weight of the heat resistant resin to a heat resistant resin of 0.10 to 0.40, heat the reaction, and then add 0.01 to 5 parts by weight per 100 parts by weight of the heat resistant resin. A heat-resistant resin composition obtained by adding melamine or a melamine derivative and dissolving them in a solvent. 2. The heat-resistant resin composition according to claim 1, wherein the polyvalent isocyanate having two or more isocyanate groups in one molecule is diphenylmethane diisocyanate or tolylene diisocyanate. 3. The heat-resistant resin composition according to claim 1 or 2, wherein the tribasic acid anhydride or its functional derivative is trimellitic anhydride. 4. The heat-resistant resin composition according to claim 1, 2, or 3, wherein the alcohol is methanol, ethanol, isopropanol, or butanol. 5. The heat-resistant resin composition according to claim 1, 2, 3, or 4, wherein the heating reaction conditions of the heat-resistant resin and alcohol are a temperature of 50 to 150°C and a time of 1 to 6 hours. thing. 6 The melamine derivative is monomethylolmelamine,
Claim 1 which is dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine, hexamethylolmelamine, or a compound in which the methylol group of these compounds is etherified with an alcohol having 1 to 4 carbon atoms. , the heat-resistant resin composition according to item 2, item 3, item 4, or item 5.