JPS6234051B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a novel polyesterimide containing an isocyanurate ring. Currently, polyester varnishes are often used as electrical insulating varnishes, especially varnishes for enameled wires, because they have relatively well-balanced mechanical properties, electrical properties, heat resistance, etc. However, recently, in order to reduce the size and weight of electrical equipment, a varnish for enameled wires with even better heat resistance is required. Varnishes for enameled wires with good heat resistance include varnishes with high heat resistance such as polyimide varnishes and polyamide-imide varnishes, but the resins themselves are expensive and pose a major cost problem. Therefore, in order to improve the heat resistance of polyester-based varnishes for enameled wires, so-called polyester imide varnishes containing imide groups as part of the resin component have been proposed. However, although polyesterimide has improved thermal shock resistance compared to polyester, it has a drawback in heat softening properties. The present inventors have completed the present invention as a result of intensive studies on the application of isocyanurate ring-containing polyisocyanates to electrically insulating materials. The present invention relates to an isocyanurate ring-containing polyimidecarboxylic acid obtained by reacting an isocyanurate ring-containing polyisocyanate obtained by trimerization of isocyanate groups with a carboxylic acid containing an acid anhydride group, a polyhydric alcohol, and the necessary The present invention relates to a method for producing a polyesterimide containing an isocyanurate ring, in which a polyhydric alcohol is reacted with another carboxylic acid in an excess of 5 to 80 equivalents relative to the acid component. The outline of the content of the present invention is shown in the following reaction formula. This is to assist in understanding the content of the present invention, and is not intended to limit the scope of the present invention. In the above formula, R ₁ is an alkylene group, aromatic group, etc., R ₂ is an alkylene group, alicyclic group, etc., and X is

[Formula] R ₃ is hydrogen or an alkyl group, R ₄ is an alkylene group, aromatic group, etc., Ar is an aromatic group, and n is an integer. The isocyanurate ring-containing polyisocyanate used in the present invention is a polyisocyanate containing an isocyanurate ring obtained by trimerizing isocyanate groups. This reaction is carried out in the presence of a solvent that does not react with the isocyanate groups.
In order to proceed with the reaction effectively, it is desirable to use an isocyanate group trimerization catalyst. As the solvent, aliphatic and aromatic hydrocarbons, halogenated aromatic hydrocarbons, esters,
It can be arbitrarily selected from ketone, ether, ethylene glycol monoalkyl monoacetate solvents, dimethyl sulfoxide, and the like. As trimerization catalysts for isocyanate groups, alkali metal acetates, metal salts and organometallic compounds such as iron, magnesium, nickel, zinc, tin, lead, panadium, and titanium, N-methylmorpholine,
1,8-diazabicyclo(5.4.0)undecane-7.2-(dimethylaminomethyl)-4.6-
Mannitz bases of phenols such as dimethylphenol, tertiary amines such as N.N-bis-(dimethylaminoethyl)-N-methylamine, etc. can be used, and there are no particular limitations. The reaction temperature for trimerizing isocyanate groups is, for example, in the range of 50 to 150°C. The actual trimerization reaction of isocyanate groups is complex, and does not necessarily selectively produce only isocyanate adducts containing only one isocyanurate ring in one molecule; unreacted isocyanate and isocyanurate rings are A mixture with two or more isocyanate adducts in one molecule is obtained. This mixture can also be used in the present invention. The amount of catalyst and reaction temperature can be determined depending on the number of isocyanurate rings contained in the isocyanate adduct, but generally the proportion of residual isocyanate groups is 50%.
For example, when conducting a reaction in which the amount of tertiary amine is about 0.01 to 2%,
Weight % and reaction temperature of 80 to 160°C are preferred. Isocyanates include ethane-1,2-diisocyanate, transvinylene diisocyanate, butane-1,4-diisocyanate, pentane-1,5-diisocyanate, and hexane-1,5-diisocyanate.
1,6-diisocyanate, diphenylsilane diisocyanate, ω・ω′-1,4-dimethylcyclohexane diisocyanate, ω・ω′-1・
4-Dimethylbenzenediisocyanate, ω・
ω'-1,4-dimethylnaphthalene diisocyanate, cyclohexane-1,4-diisocyanate, 1,4-phenylene diisocyanate, diphenyl ether-4,4'-diisocyanate, naphthalene-1,4-diisocyanate, biphenyl-4, 4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, 4,
4′-dimethoxydiphenylmethane-3・3′-diisocyanate, diphenylsulfide-4・
4'-diisocyanate, diphenyl sulfone-
Diisocyanates such as 4,4'-diisocyanate are used, and monoisocyanates, polymethylene polyphenyl isocyanate, triphenylmethane triisocyanate, tris (4-phenyl isocyanate thiophosphate), 3,3',
A trivalent or higher valent polyisocyanate such as 4,4'-diphenylmethanetetrisocyanate may be used in combination. In consideration of cost and heat resistance, aromatic diisocyanates, particularly 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, and xylylene diisocyanate are preferred. The reaction between the isocyanenute ring-containing polyisocyanate and the acid anhydride group-containing carboxylic acid may be carried out by adding the acid anhydride group-containing carboxylic acid to the reaction solution of the isocyanate ring-containing polyisocyanate. Isocyanurate ring-containing polyisocyanates can be used with different numbers of isocyanurate rings depending on the application, but they are heat resistant,
In terms of flexibility, etc., it is preferable to have a residual isocyanate group content of 10 to 70% (assuming the isocyanate group content in the diisocyanate to be 100). As the carboxylic acid containing an acid anhydride group, for example, compounds represented by the general formulas () and () are used, and the carboxylic acid containing an acid anhydride group that reacts with an isocyanate group or its derivative (R=H alkyl group, phenyl group, etc.) (X= _-CH2- , -CO-, _-SO2- , -O-, etc.) There is no particular restriction as long as it is a body. In consideration of heat resistance, cost, etc., trimellitic acid anhydride is preferred. The amount used may be selected so that the isocyanate group and the acid anhydride group are approximately equivalent. As the reaction solvent, the solvent used in the synthesis of the isocyanurate ring-containing polyisocyanate can be used as is, but phenol, cresols, dimethylacetamide, N-methylpyrrolidone, etc. may also be used. The reaction temperature is 130
~180°C is preferred. The progress of the reaction can be checked by observing the bubbles of carbon dioxide gas generated. The reaction of polyimide carboxylic acids, polyhydric alcohols, and other carboxylic acids is an esterification reaction. In addition to the above-mentioned isocyanurate ring-containing polyimide carboxylic acid, other carboxylic acids used in the esterification reaction include benzoic acid, terephthalic acid, isophthalic acid, trimellitic acid, succinic acid, adipic acid, pyromellitic acid, and benzophenonetotetra. Derivatives such as carboxylic acid, butanetetracarboxylic acid, esters thereof, acid anhydrides, etc. may be used in combination. The isocyanurate ring-containing polyimide carboxylic acid can be used alone, but in consideration of heat resistance and flexibility, the content of the isocyanurate ring-containing polyimide carboxylic acid in the acid component is preferably about 10 to 80 equivalent %. If the content is too small, no improvement in heat resistance can be expected, and if the content is too large, the flexibility will decrease and it will be difficult to obtain a suitable coating film, which is not preferable. Polyhydric alcohols generally include polyesters, alcohols used in synthesis, such as ethylene glycol, diethylene glycol, nuopentyl glycol, 1,4-butanediol,
Dihydric alcohols such as 1,6-hexanediol and 1,4-cyclohexanedimethanol, and trihydric or higher alcohols such as glycerin, trimethylolpropane, tris(2-hydroxyethyl)isocyanurate, and pentaerythritol are used. The amount of polyhydric alcohol to be used is preferably 5 to 80 equivalent percent excess relative to the acid component from the viewpoint of heat resistance and the like. As for the synthesis method, it is also possible to mix the isocyanurate ring-containing polyimide carboxylic acid, a polyhydric alcohol, and if necessary, another carboxylic acid, and synthesize without a solvent, but it is preferable to use a high boiling point solvent such as cresol. , N-methylpyrrolidone, xylenol, etc. are preferably used in combination. Synthesis can also be carried out by adding a polyhydric alcohol and other carboxylic acids as necessary to the reaction solution used in the previous step, and further adding the above-mentioned high boiling point solvent as appropriate. Other carboxylic acids can also be added later for the purpose of speeding up the reaction. The synthesis temperature is
A range of 160°C to 250°C is preferred. The progress of the reaction can be determined by the amount of condensed water, viscosity, etc. As the synthesis catalyst, general esterification and transesterification catalysts such as tetrabutyl titanate, lead acetate, cobalt naphthenate, and dibutyltin oxide are used. The isocyanurate ring-containing polyesterimide obtained in this way or its solution can be used in cresol, xylenol, N-methylpyrrolidone,
It is diluted to a resin content of 20 to 50% by weight with a solvent such as dimethylformamide or dimethylacetamide. In this case, xylene, ethylene glycol dimethyl ester, NISSEKI HISOL are used as co-solvents.
-100 (trademark of aromatic hydrocarbon manufactured by Nippon Petrochemical Co., Ltd.), ethylene glycol monoethyl monoacetate, etc. may be used in combination. Titanium, which is generally used as a curing agent for polyester resin, is added to the resin solution obtained in this way.
An organometallic compound such as aluminum, such as tetrabutyl titanate, tetrapropyl titanate, aluminum tris (acetylacetonate), etc. is added, and an organometallic compound such as zinc cobalt is added as a surface smoothing agent, such as zinc naphthenate, cobalt naphthenate. etc. are added. In addition, as a curing agent, blocking isocyanate,
For example, Desmodyur CT Stable (manufactured by Nippon Polyurethane Industries Co., Ltd.) or the like may be added. The coating film created using the varnish thus obtained exhibits good heat resistance. The present invention will be explained by means of comparative examples and examples. Comparative example 1

[Table] Place the above ingredients in a four-necked flask equipped with a thermometer, stirrer, and fractionator tube, and place in a nitrogen stream.
The temperature is increased to 170°C and then to 230°C at a rate of 10°C/hour. The mixture was kept at 230°C and the reaction was allowed to proceed until the gelation time on a 250°C hot plate became 120 seconds or less. Next, cresol/xylene (weight ratio = 7/
3) Make the resin concentration 30% by weight with a solution. Tetrabutyl titanate (5% by weight based on the resin content) and zinc naphthenate (0.2% by weight based on the resin content) were added to the obtained resin solution to obtain a varnish. Comparative example 2

[Table] Put the above ingredients into a four-necked flask equipped with a thermometer, stirrer, and fractionator tube, and adjust the temperature in a nitrogen stream.
increased to 170°C, then 210°C at a rate of 10°C/hour
The temperature rises to The mixture was kept warm at 210°C, and the reaction was allowed to proceed until the gelation time on a hot plate at 210°C became 100 seconds or less. Next, cresol/xylene (weight ratio = 7/
3) Make the resin concentration 30% by weight with a solution. Tetrabutyl titanate (5% by weight based on the resin content) and zinc naphthenate (0.2% by weight based on the resin content) were added to the obtained resin solution to obtain a varnish. Comparative Example 3 (1) Synthesis of aromatic diimide dicarboxylic acid

[Table] Put the above ingredients into a 4-necked flask equipped with a thermometer and a stirrer, react in a nitrogen stream at 100℃ for 3 hours, then raise the temperature to 150℃, and at the same temperature no carbon dioxide gas is generated. The reaction proceeded until. After cooling to room temperature, 5 times the volume of methanol was added to this solution to remove a pale yellow precipitate, 2% by weight NaOH aqueous solution was added, the mixture was stirred well, the treated product was thoroughly washed with water and dried to give 350 g of diimide dicarboxylic acid. I got it. In the infrared spectrum of this product, imide group absorption was observed at 1780 cm ^-1 .
No absorption of isocyanate groups was observed. (2) Synthesis of polyesterimide

[Table] The above ingredients were placed in a four-necked flask equipped with a thermometer, stirrer, and fractionator tube, and reacted in a nitrogen stream at 180 to 200°C until almost no methanol was distilled out by the reaction. ℃, and gelation time on a 250℃ hot plate at the same temperature.
The reaction was allowed to proceed until the time was 120 seconds or less. Add cresol to the hot resin to make the resin concentration 30% by weight.
Further, the resin solution was kept at 110°C, and 5% by weight of tetrabutyl titanate based on the resin content was gradually added, and stirring was continued for 30 minutes to obtain a varnish. Example 1 (1) Synthesis components of aromatic diisocyanate trimer Gram tolylene diisocyanate 600 Xylene 600 2-dimethylaminoethanol (catalyst) 1.8 Place the above ingredients in a four-necked flask equipped with a thermometer and a stirrer. The temperature was raised to 140°C in a nitrogen stream, and the reaction was allowed to proceed at the same temperature until the content of isocyanate groups (initial concentration: 48% by weight) reached 20% by weight. The infrared spectrum of this thing has 1710cm
^-1 , absorption of isocyanurate rings was observed at 1410 cm ^-1 , and absorption of isocyanate groups was observed at 2260 cm ^-1 . (2) Synthesis of polyimide carboxylic acid

[Table]
The above ingredients were placed in a four-necked flask equipped with a thermometer and a stirrer, and the temperature was raised to 150°C in a nitrogen stream. Then, xylene was distilled off, and the reaction was continued at 160-180°C until no carbon dioxide gas was generated. I proceeded. After the reaction, 200 g of cresol was added. In the infrared spectrum of this product, absorption of isocyanurate rings was observed at 1710 cm ^-1 and 1410 cm ^-1 , and absorption of imide group was observed at 1780 cm ^-1 . No absorption of isocyanate groups was observed. (3) Synthesis of isocyanate ring-containing polyesterimide

[Table] The above ingredients were placed in a four-necked flask equipped with a thermometer, stirrer, and fractionator tube, and reacted in a nitrogen stream at 160 to 170°C until almost no methanol was distilled out by the reaction. ~220℃
The reaction was continued at the same temperature until the gelation time on a 250°C hot plate became 120 seconds or less. Add cresol to the hot resin to make the resin concentration 30% by weight. Further, the resin solution was maintained at 110° C., and 5% by weight of tetrabutyl titanate based on the resin content was gradually added, and stirring was continued for 30 minutes to obtain a varnish. In the infrared spectrum of the resin component of this product, absorption of isocyanurate rings was observed at 1710 cm ^-1 and 1410 cm ^-1 , absorption of imide group was observed at 1780 cm ^-1 , and absorption of ester bond was observed at 1720 cm ^-1 . was recognized. Example 2 (1) Synthesis components of aromatic diisocyanate trimer Gram tolylene diisocyanate 600 Xylene 600 2-dimethylaminoethanol (catalyst) 1.8 Place the above ingredients in a four-necked flask equipped with a thermometer and a stirrer. The temperature was raised to 140°C in a nitrogen stream, and the reaction was allowed to proceed at the same temperature until the content of isocyanate groups (initial concentration: 48% by weight) reached 25% by weight. The infrared spectrum of this thing has 1710cm
^-1 , absorption of isocyanurate rings was observed at 1410 cm ^-1 , and absorption of isocyanate groups was observed at 2260 cm ^-1 . (2) Synthesis of polyimide carboxylic acid

[Table] The above ingredients were placed in a four-necked flask equipped with a thermometer and a stirrer, and the temperature was raised to 140°C in a nitrogen stream, and then the reaction was allowed to proceed at 150-170°C until no carbon dioxide gas was generated. In the infrared spectrum of this product, absorption of isocyanurate rings was observed at 1710 cm ^-1 and 1410 cm ^-1 , and absorption of imide group was observed at 1780 cm ^-1 . No absorption of isocyanate groups was observed. (3) Synthesis of isocyanurate ring-containing polyesterimide

[Table] The following was synthesized in the same manner as in Example 1 (3), and then a varnish was prepared. Example 3 Synthesis of isocyanurate ring-containing polyesterimide

[Table] Polyimide carboxylic acid, ethylene glycol,
Place the catalyst and cresol into a four-necked flask equipped with a thermometer, stirrer, and fractionator tube, and place in a nitrogen stream.
After reacting at 200 to 220°C for 4 to 5 hours, add tris(2-hydroxyethyl)isocyanurate and dimethyl terephtate, and react at 180 to 200°C until almost no methanol is distilled out by the reaction, and then continue to react. Raised the temperature to 220℃, then 250℃ at the same temperature
The reaction was allowed to proceed until the gelation time on the hot plate was 120 seconds or less. Add cresol to the hot resin to make the resin concentration 30% by weight. Further, the resin solution was kept at 110°C, and 5% by weight of tetrabutyl titanate based on the resin content was gradually added, and stirring was continued for 30 minutes to obtain a varnish. Example 4 Synthesis of isocyanurate ring-containing polyesterimide

[Table] The following was synthesized in the same manner as in Example 1 (3), and then a varnish was prepared. Example 5 Synthesis of isocyanurate ring-containing polyesterimide

[Table] After synthesizing according to Example 3, a varnish was prepared. Example 6 (1) Synthesis component of aromatic diisocyanate trimer Gram Diphenylmethane 4,4'-diisocyanate
150 Ethylene glycol monoethyl ether monoacetate 150 1,8-diaza-bicyclo(5.4.0) undecene-7 (catalyst) 0.45 Place the above ingredients in a four-necked flask equipped with a thermometer and stirrer in a nitrogen stream. The temperature was raised to 160°C, and the reaction was continued at the same temperature until the content of isocyanate groups (initial concentration: 34% by weight) reached 15.5% by weight. The infrared spectrum of this thing has 1710
cm ^-1 , absorption of isocyanurate rings was observed at 1410 cm ^-1 , and absorption of isocyanate groups was observed at 2260 cm ^-1 . (2) Synthesis of polyimide carboxylic acid

[Table] The above ingredients were placed in a four-neck flask equipped with a thermometer and a stirrer, and the temperature was raised to 140°C in a nitrogen stream, and then the reaction was allowed to proceed at 150-180°C until no carbon dioxide gas was generated. In the infrared spectrum of this product, absorption of isocyanurate rings was observed at 1710 cm ^-1 and 1410 cm ^-1 , and absorption of imide group was observed at 1780 cm ^-1 . No absorption of isocyanate groups was observed. (3) Synthesis of isocyanurate ring-containing polyesterimide

【table】

[Table] The following was synthesized in the same manner as in Example 1 (3), and then a varnish was prepared. Table 1 shows the properties of the cured varnish film obtained as described above.

[Table] Compared to the polyester of Comparative Example 1 and the polyester imide of Comparative Examples 2 and 3, all of Examples 1 to 5 have a higher thermal softening temperature of 20 to 55°C, which is an important property of heat-resistant insulating materials. Looking at the thermogravimetric loss rate, which indicates the difficulty of decomposition, it can be seen that it is about 15 to 40 degrees Celsius higher. The same can be said about Example 6. As can be seen from the above examples, polyesterimide using isocyanurate rings is a resin with excellent heat resistance.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus used for measuring thermal softening temperatures in Examples. Explanation of symbols, 1...Load, 2...Supporting metal fittings, 3
... Sample, 4 ... Painted surface, 5 ... Steel ball, 6 ... Washer, 7 ... Steel plate, 8 ... Insulating plate, 9 ... AC power supply.

Claims (1)

[Scope of Claims] 1. Isocyanurate ring-containing polyimide carboxylic acid, polyvalent, obtained by reacting an isocyanurate ring-containing polyisocyanate obtained by trimerization of isocyanate groups with a carboxylic acid containing an acid anhydride group. 1. A method for producing a polyesterimide containing an isocyanurate ring, which comprises reacting an alcohol and, if necessary, another carboxylic acid with the polyhydric alcohol in an excess of 5 to 80 equivalents relative to the acid component. 2. Claims in which the isocyanurate ring-containing polyisocyanate obtained by trimerizing isocyanate groups is an isocyanurate ring-containing polyisocyanate obtained from 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, or xylylene diisocyanate. A method for producing a polyesterimide containing an isocyanurate ring according to item 1. 3. Isocyanurate ring-containing polyisocyanate obtained by trimerization of isocyanate groups is
A method for producing an isocyanurate ring-containing polyesterimide according to claim 1 or 2, which is an isocyanurate ring-containing polyisocyanate having a residual isocyanate content of 10 to 70 percent. 4. Claims 1 and 2, wherein the carboxylic acid containing an acid anhydride group is trimellitic anhydride.
A method for producing a polyesterimide containing an isocyanurate ring according to item 1, 3 or 4. 5 Claims 1 and 2, in which the acid component contains 10 to 80 equivalent % of polyimide carboxylic acid;
A method for producing a polyesterimide containing an isocyanurate ring according to item 3 or 4.