JP2963190B2 - Method for producing polyester imide and wire enamel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel method for producing polyesterimide and a method for producing wire enamel using the same.
More specifically, in the synthesis of a polyesterimide having an isocyanurate bond in the molecular structure, glycol, aromatic tricarboxylic acid and / or anhydride thereof, aromatic diamine, and cyanuric acid or an isomer thereof are used as a starting material thereof, and The present invention relates to a novel method for producing a polyesterimide, which is characterized by causing a heat reaction with a dicarboxylic acid, and a method for producing a wire enamel using the same.

(Prior Art) Conventionally, polyester resins have been awarded as general-purpose wire enamels because of their excellent electrical, thermal and mechanical properties. In recent years, the demand for wire enamel has increased with the miniaturization and high performance of electrical equipment, and the demand for wire enamel using polyesterimide as a polyester resin with high heat resistance and good balance of properties has increased. doing.

As a method of imparting heat resistance to polyesterimide, it has been found that an isocyanurate bond is arranged in the molecular structure, and tris (2-hydroxyethyl) isocyanurate (hereinafter abbreviated to THEIC) is used as a polyhydric alcohol segment. The method has been implemented for at least the last 20 years. The effectiveness of using THEIC as a raw material for heat-resistant polyesterimide is fully described in U.S. Pat. No. 3,426,098 and JP-B-45-33,146.

THEIC, a raw material of heat-resistant polyesterimide, is produced on a commercial scale by the reaction of cyanuric acid and ethylene oxide.To avoid accidents that may occur due to the use of ethylene oxide, the place where THEIC is produced is It is very limited and therefore has a limited number of THEIC manufacturing plants around the world and is expensive.

(Problems to be Solved by the Invention) Accordingly, an object of the present invention is to provide a novel method for producing a heat-resistant polyesterimide having an isocyanurate bond in a molecular structure without using THEIC in the production of a polyesterimide. An object of the present invention is to provide a method for producing a used wire enamel.

The entire range to which the present invention can be applied will be clear from the following detailed description and examples. However, the detailed description and the preferred embodiments of the present invention are illustrative only, and it will be apparent to those skilled in the art that various changes and modifications can be made within the spirit and scope of the present invention. It is.

(Means for Solving the Problems) These objects are to provide an isocyanurate bond in the molecular structure of polyester imide, using cyanuric acid or its isomer as a starting material instead of THEIC, glycol, aromatic By reacting with tricarboxylic acid and / or its anhydride, aromatic diamine and dicarboxylic acid by heating, 1 mol of THEIC can be replaced by 1 mol of cyanuric acid and at least 3 mol of ethylene glycol. This is achieved by a method for producing a polyesterimide having substantially the same molecular structure as that used.

(1) A molecular structure characterized by reacting cyanuric acid or its isomer, glycol, dicarboxylic acid, aromatic tricarboxylic acid and / or anhydride and aromatic diamine in the presence or absence of a solvent. A method for producing a polyesterimide having an isocyanurate bond therein, (2) cyanuric acid or an isomer thereof, an aromatic tricarboxylic acid and / or an anhydride thereof, and a pre-condensate obtained by previously reacting a glycol and a dicarboxylic acid; (1) The method for producing polyesterimide according to the above (1), wherein the reaction is carried out by adding an aromatic diamine, and (3) glycol, dicarboxylic acid, aromatic tricarboxylic acid and / or anhydride thereof, and aromatic diamine in advance. To a precondensate obtained by reacting (1) The method for producing a polyesterimide according to (1), wherein the glycol is ethylene glycol, the dicarboxylic acid is terephthalic acid, an aromatic tricarboxylic acid and / or This is a method for producing a polyesterimide in which the anhydride is trimellitic anhydride and the aromatic diamine is 4,4'-diaminodiphenylmethane.

Further, in the presence or absence of a solvent, at least one glycol selected from the group consisting of cyanuric acid or an isomer thereof, ethylene glycol, propylene glycol, and neopentyl glycol, a dicarboxylic acid, an aromatic tricarboxylic acid, and / or an anhydride thereof. Products and aromatic diamines react to imidize 20-40%
Thus, a polyester imide having an isocyanurate bond in the molecular structure is obtained, and the polyester imide is dissolved in a solvent.

(Action) The method for producing a polyesterimide according to the present invention is based on THEI
A method for producing a heat-resistant polyesterimide having an isocyanurate bond in a molecular structure by heat-reacting C, glycol, an aromatic tricarboxylic acid and / or an anhydride thereof, an aromatic diamine and a dicarboxylic acid,
A novel method for producing a heat-resistant polyesterimide characterized by using cyanuric acid or an isomer thereof and glycol in place of THEIC, and a wire enamel containing the heat-resistant polyesterimide obtained by this method. It is.

In the production of the heat-resistant polyester imide of the present invention,
The reaction components are brought to a temperature of 150 ° C. or higher, preferably
It is preferable to react by heating to 50 to 270 ° C.

The composition of the reaction components in the present invention is as described above, but when introduced in detail, the glycols that can be used include ethylene glycol, propylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and 1,6. -Hexanediol, N, N'-bishydroxyethyl-5,5 -'- dimethylhydantoin, diethylene glycol, dipropylene glycol, bishydroxyethyl terephthalate, etc., but ethylene is considered to give the same molecular structure as THEIC. Glycol is optimal.

Cyanuric acid has a tautomeric relationship as shown in the following formula, and takes a structure of isocyanuric acid when heated to 150 ° C. or more. Therefore, any structure of isomers can be used when compounding.

As the imide-forming component, an aromatic tricarboxylic acid or its anhydride and an aromatic diamine are blended, and as the aromatic tricarboxylic acid or its anhydride, trimellitic acid or its anhydride, 3,4,4'-benzophenone tricarboxylic acid is used. Acid anhydrides and 3,4,4'-biphenyltricarboxylic anhydrides are preferred, but trimellitic acid or its anhydride is most preferred from the viewpoint of versatility.

As aromatic diamines, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'diaminodiphenylether, 4,4'-diaminodiphenyl Cyclohexane, 4,4'-diaminodiphenylsulfone, 1,4-phenylenediamine, 1,3-phenylenediamine and the like, but 4,4'-diaminodiphenylmethane, 4,4 '
-Diaminodiphenyl ether can be preferably used.

An imide-forming component, such as trimellitic acid or its anhydride, reacts with an aromatic diamine to produce a carboxylic acid containing an imide bond. Acid or anhydride 2 thereof. Both components produce a diimide dicarboxylic acid having the following structural formula.

(The formula is a case where the diamine is 4,4'-diaminodiphenylmethane.) From this fact, the aromatic tricarboxylic acid or its anhydride is calculated as monovalent when calculating the OH / COOH ratio. The mixing ratio of the aromatic tricarboxylic acid or its anhydride is preferably the same as described above.
A blending width of about 2.1 moles is acceptable. If the diamine is excessive, an amide bond is partially formed, and if the aromatic tricarboxylic acid or its anhydride is excessive, it reacts with glycol as a trivalent carboxylic acid to form a triester.

Dicarboxylic acids include terephthalic acid, isophthalic acid,
Naphthalenedicarboxylic acids or lower alkyl esters thereof, for example, dimethyl terephthalate, diethyl terephthalate, dipropyl terephthalate and their corresponding isophthalates, naphthalates, as well as mixtures of their esters and acids can be used,
Terephthalic acid and terephthalate are preferred from the viewpoint of heat resistance and versatility.

As the dicarboxylic acid, in addition to the above compounds, adipic acid, azelaic acid, sebacic acid, decandioic acid and the like can be blended as required. Further, as a source of the aliphatic glycol and the dicarboxylic acid component, a high molecular polyester such as polyethylene terephthalate, isophthalate, naphthalate or a copolymer thereof can be used. In this case, it is necessary to calculate the composition by adding the value obtained by dividing the amount used by the basic units of the dicarboxylic acid component and the glycol component constituting the high molecular polyester to the equivalent number of each component.

Hydroxyl group in the production of the polyesterimide of the present invention /
The ratio of the acid groups is 1.2 to 2.0 as the ratio of the total hydroxyl groups of the glycol used to the total acid groups of the cyanuric acid, dicarbic acid and diimide dicarboxylic acid formed by the imide-forming component described above.

If it is less than 1.2, the viscosity of the reaction system is high and the progress of the reaction is not smooth.If it is more than 2.0, the molecular weight of the reaction product is too small, and the coating stability as a wire enamel is difficult, and good curing is obtained. I can't. More preferably
1.3 to 1.8.

The imide content in the polyesterimide can be arbitrarily changed, but is preferably 10% or more, particularly preferably 20 to 40%, for the purpose of maintaining the properties as the polyesterimide. The calculation method is disclosed in UK Patent No. 1,082,181 and is well known to those skilled in the art.

In the present invention, as a method of arranging an isocyanurate bond in the molecular structure of polyesterimide, cyanuric acid or an isomer thereof is reacted with glycol instead of the conventional THEIC, and cyanuric acid or dicarboxylic acid having an acid group of cyanuric acid is used. And the ratio to the total acid groups of the diimidedicarboxylic acid formed by the imide-forming component is 20 to 60% by weight.

If it is less than 20 equivalent%, the heat resistance is inferior, and the paint stability as a wire enamel is difficult. If it exceeds 60 equivalent%, the reaction system has high viscosity, so it is difficult to control the reaction and the cured film is brittle. , It is difficult to obtain good characteristics. More practically, 40 to 55 equivalent% is a preferable range.

In the present invention, the production of the polyesterimide can take the following embodiments. In these embodiments, a normal solvent such as cresylic acid or N-methylpyrrolidone can be used as a reaction solvent, and the generated water is promptly removed from the reaction system by azeotropic distillation of hydrocarbons. Can be used for

Furthermore, in the production of these polyesterimides,
It is possible and preferred to use a catalyst to promote the reaction. Examples of catalysts that can be used include tetrapropyl titanate, tetrabutyl titanate, tetracresyl titanate, titanates such as triethanolamine titanate, and tin compounds such as dibutyltin oxide and stannas oxide, and zinc acetate and lead acetate. And organic metal lead such as zinc propionate, and these can be used in combination of two or more. Usually, it is used in an amount of 2% by weight or less based on the total of the reaction components.

(1) In the presence or absence of a catalyst, glycol, cyanuric acid, dicarboxylic acid and an imide-forming component are charged into a reaction vessel together with a reaction solvent as necessary, and heated and reacted at 150 to 270 ° C. to obtain a polyesterimide. Provide for wire enamel preparation.

(2) Glycol and dicarboxylic acid are charged to a reaction vessel in the presence or absence of a catalyst and heated at 170 to 230 ° C to obtain a polyester, and then the batch is cooled to 150 ° C or lower to form cyanuric acid and imide forming components. And, if necessary, a reaction solvent is added. The batch is heated and reacted at 150 to 270 ° C. to obtain a predetermined polymerized polyesterimide, which is subjected to wire enamel preparation. The solvent for the reaction may be charged from the beginning.

(3) A part of glycol and the entire amount of dicarboxylic acid are charged into a reaction vessel in the presence or absence of a catalyst, and
C. to obtain the polyester, then the batch is
The mixture is cooled to 0 ° C. or lower, and the remainder of the glycol, cyanuric acid, imide-forming components and, if necessary, a solvent for reaction are added.
The batch is heated and reacted at 150 to 270 ° C. to obtain a predetermined polymerized polyesterimide, which is subjected to wire enamel preparation. The solvent for the reaction may be charged from the beginning.

(4) In the presence or absence of a catalyst, glycol, dicarboxylic acid and / or imide-forming components and, if necessary, a reaction solvent are charged into a reaction vessel and heated at 180 to 230 ° C. to obtain a polyesterimide. Batch 20
After cooling to 0 ° C. or lower, cyanuric acid is added, and the mixture is heated and reacted at 150 to 270 ° C. to obtain a polymerized polyesterimide, which is provided for wire enamel preparation.

The production mode of the above polyester imide is an example,
It is to be understood that the order of addition of the reaction components and the order of the reaction, like the batch temperature during the reaction, can be varied without being limited to the above examples.

Polyester imide produced by the above method,
It can be collected as a solid or semi-solid, and these resins are finally dissolved in a solvent and used as wire enamel. Instead of collecting as a solid or semi-solid, these resins are dissolved in the same solvent as the wire enamel forming solvent at the end of the reaction. In this case, the reaction system is cooled to 240 ° C. or lower, the solvent is directly added to the reaction vessel, and the mixture is uniformly mixed at 180 to 240 ° C. Then transfer to another container or 15 in the same container
By cooling the mixture to 0 ° C. or lower and mixing an additional solvent, the solid content and viscosity can be adjusted to target ranges to obtain a wire enamel.

Solvents that can be used as a wire enamel forming solvent include N-methylpyrrolidone, dimethylacetamide, dimethylformamide, dimethylsulfoxide, N-
Methylcaprolactam, cresylic acid, m- and p-
A cresol mixture, acetophenone, methyl benzoate, γ-butyrolactone, glycol ethers, lower alkyl esters of aliphatic dicarboxylic acids such as dimethyl adipate can be used, but commercially available cresylic acids are generally preferred. In addition, aromatic hydrocarbons such as aliphatic and aromatic naphtha and xylene can be used in combination as diluents.

The polyester imide wire enamel thus prepared can be subjected to enamel wire production as it is, but a curing agent and a modifier used in a conventional polyester imide wire enamel can be mixed and used to obtain better properties, For example, zinc naphthenate, metal salts of organic acids such as zinc octylate, and titanates such as tetraisopropyl titanate, tetrabutyl titanate, tetracresyl titanate, and triethanolamine titanate can be used as a curing catalyst. 0.5 to 15% by weight, especially 1
A range of 〜10% by weight is preferred.

It can be modified by blending a cresol-formaldehyde resin in a solid content ratio of up to 20% by weight with respect to the polyesterimide resin content. Also, instead of cresol-formaldehyde resin, phenol-formaldehyde resin, xylenol-formaldehyde resin,
Alternatively, a mixture of formaldehyde resins of phenols can be used.

It can be modified by blending a stabilized polyisocyanate in a solid content ratio of up to 20% by weight with respect to the polyesterimide resin component. Examples of the stabilized polyisocyanate include phenol-blocked diphenylmethane diisocyanate, phenol-blocked product of 3 mol of diphenylmethane diisocyanate or adduct of toluylene diisocyanate and trimethylolpropane, and phenol block of cyclic trimer of toluylene diisocyanate. There are monsters. From the viewpoint of heat resistance, a cyclic trimer of toluylene diisocyanate is preferable,
As a commercial product, Bayer's Desmodur CT (Desmodur CT)
CT), Mobay Chemical's Mondur SH
SH) can be used equally.

(Example) In order to explain the present invention in more detail, an example is shown below.

 The following abbreviations are used in the examples.

EG = ethylene glycol PG = propylene glycol NPG = neopentyl glycol CA = cyanuric acid TPA = terephthalic acid TMA = trimellitic anhydride DAM = 4,4'-diaminodiphenylmethane TPT = tetraisopropyl titanate TBT = tetrabutyl titanate TET = triethanol Amine titanate THEIC = Tris (2-hydroxyethyl) isocyanurate PET = Polyethylene terephthalate SW1000 = Aromatic naphtha “Swazol 10 manufactured by Maruzen Oil Co., Ltd.
00 "Desmodur CT = cyclic trimer phenol block of toluylene diisocyanate manufactured by Bayer Co. Mondur SH = cyclic trimer phenol block of toluylene diisocyanate manufactured by Mobay Chemical Co. Example 1 Stirrer, thermometer and water produced EG500.5g, CA225.7g, in a flask with a capacity of 2 equipped with a fractionation cooling tube for recovery
TPA344g, TMA303g, DAM156g and TBT1.5g as a catalyst were charged, and stirring and heating were started. The reaction system is 110 ° C
Around this area, the product becomes a cake-like form, and the generated water starts to distill at around 150 ° C.
The reaction was continued at 235 ° C. Sampling was started when the CA crystals disappeared from the reaction system, and the concentration of 30% by weight m-, p
-Gardner viscosity of the cresol solution at 25 ° C is U1 / 2
, Heating was stopped, the reaction product was transferred to a tin can, cooled and pulverized to obtain a target polyesterimide resin.

Next, the polyesterimide resin obtained above was placed in another flask having a capacity of 2 and equipped with a stirrer, a thermometer and a cooling tube.
600 g, m-cresylic acid 558 g, and SW1000 naphtha 100 g were charged and heated to 140 ° C. to be uniformly dissolved. Thereafter, the mixture was cooled to 100 ° C., and 50% by weight of cresol-formaldehyde resin was used.
24 g of cresol solution, 50 wt% cresol solution of TPT
After adding 48 g, stirring and mixing, the mixture was cooled to 90 ° or lower, and filtered using a qualitative filter paper.
A polyester imide wire enamel having a viscosity of 55 poise at ° C was obtained.

Reference Example EG175.1g, THEIC457g, T
PA344g, TMA303g, DAM156Og, and TBT1.5g as a catalyst were charged, stirring and heating were started, and the temperature was raised in sequence while collecting fresh water, and the reaction was continued at a maximum temperature of 235 ° C. When the TPA disappeared from the reaction system, sampling was started, and when the Gardner viscosity at 25 ° C. of the 30% by weight concentration m-, p-cresol solution at 25 ° C. became U1 / 2, the heating was stopped.
The reaction product was transferred to a tin can, cooled and pulverized to obtain a desired polyesterimide resin.

Next, the polyesterimide resin obtained in the same manner as in Example 1 was treated to obtain a polyesterimide wire enamel having a viscosity of 56 poise at 30 ° C. at a resin content of 45.2% by weight measured.

Example 2 A polyesterimide resin was obtained in the same manner as in Example 1, except that PG (613.5 g) was used instead of EG as glycol.

Next, 650 g of the polyesterimide resin obtained above, 604 g of m-cresylic acid and 106 g of SW1000 naphtha were placed in another flask having a capacity of 2 and equipped with a stirrer, a thermometer and a condenser.
And heated to 140 ° C. to dissolve uniformly. Then one
After cooling to 00 ° C., the same amount of the modifying agent as in Example 1 was added, and the same treatment was carried out to obtain a polyesterimide wire enamel having a resin content of 43.5% by weight measured and a viscosity of 50 poise at 30 ° C.

Example 3 A polyesterimide resin was obtained in the same manner as in Example 1, except that 420 g of NPG and 250.3 g of EG were used as glycols instead of EG.

Next, the polyesterimide resin obtained above was placed in another flask having a capacity of 2 and equipped with a stirrer, a thermometer and a cooling tube.
670 g, m-cresylic acid 622 g and SW1000 naphtha 110 g were charged and heated to 150 ° C. to be uniformly dissolved. Then 100
C., the same amount of the modifier as in Example 1 was added, and the same treatment was carried out. The measured resin content was 43% by weight, and the viscosity at 30 ° C.
A 60 poise polyester imide wire enamel was obtained.

Example 4 EG was added to a flask having a capacity of 3 and equipped in the same manner as in Example 1.
424 g, TPA 323 g, and TBT 2 g as a catalyst were charged, and stirring and heating were started. The temperature of the reaction system was maintained at 200 to 210 ° C., and when 55 g of produced water was recovered, 235 g of cresylic acid was added and cooled to 150 ° C. or lower. Next, CA219 g, TMA286 g and DAM147 g were added to the precondensate, and heating and heating were started again. The reaction system became a cake soon after the imide-forming component was dispersed, but gradually became loose as the reaction proceeded. The temperature was raised gradually while collecting the produced water, and the reaction was continued at the maximum temperature of 235 ° C. Sampling was started when the CA crystals disappeared from the reaction system, and the concentration was 30% by weight.
When the Gardner viscosity of the-, p-cresol solution at 25 ° C reached Z4, heating was stopped, 936 g of m-cresylic acid was added, and the mixture was stirred and mixed uniformly. The recovered amount of generated water was about 227 g.

The mixture was transferred to another 5 volume flask equipped with a stirrer, thermometer and condenser, and 555 g of cresylic acid and
After adding 300 g of SW1000 naphtha and mixing uniformly, the mixture was cooled to 100 ° C., and 117 g of a 50% by weight cresol solution of cresol / xylenol formaldehyde resin was added to this mixture, and 5 g of TPT was added.
117 g of a 0% by weight cresol solution was added and mixed with stirring.
The mixture was cooled to 0 ° C. or lower, and filtered using a qualitative filter paper to obtain a polyesterimide wire enamel having a measured resin content of 35% by weight and a viscosity of 50 poise at 30 ° C.

Example 5 In a flask having a capacity of 2 similar to that of Example 1, 435 g of EG and PET resin 379 were used as feed components of dicarboxylic acid and glycol.
g and 1.5 g of TBT as a catalyst, heating and stirring were started, and the temperature of the reaction system was maintained at 200 to 210 ° C. for 2 hours to completely dissolve the PET resin, followed by cooling to 150 ° C. or lower. Next, 215 g of CA, 288 g of TMA, and 148 g of DAM were added, and heating and heating were started again.
The reaction was continued at 235 ° C. Sampling was started when the CA crystals disappeared from the reaction system, and the concentration of m-, p was 40% by weight.
When the Gardner viscosity at 25 ° C. of the cresol solution reached near Y, the heating was stopped, and the reaction product was transferred to a tin can, cooled and pulverized to obtain the desired polyesterimide resin. The recovered amount of generated water was 145 g.

Next, the polyesterimide resin obtained above was placed in another flask having a capacity of 2 and equipped with a stirrer, a thermometer and a cooling tube.
600 g, m-cresylic acid 654 g and SW1000 naphtha 164 g were charged, heated to 150 ° C., and uniformly dissolved and mixed. Then one
After cooling to 00 ° C, 22 g of TBT, 48 g of a 50% by weight cresol solution of cresol-formaldehyde resin, and 54 g of Mondur SH polyisocyanate were added and completely dissolved and mixed. A polyester imide wire enamel having an actual resin content of 40% by weight and a viscosity of 15 poise at 30 ° C. was obtained.

Example 6 738 g of cresylic acid, 1250 g of EG, and 3.6 g of TBT as a catalyst were charged into a flask equipped with the same equipment as in Example 1 and having a capacity of 5, and heating and stirring were started. TPA around 100 ° C during heating
463 g, 1249 g of TMA and 644 g of DAM were added and dispersed. The reaction system became a hard cake at around 120 ° C., and at around 150 ° C., the distilling of produced water started. The temperature was raised sequentially while collecting the produced water, and the reaction was continued at a maximum temperature of 210 ° C. The cake state gradually loosened with the progress of the reaction, and eventually became a yellow-brown slurry. Collected 250 g of generated water and once 15
Cooled to below 0 ° C. Next, CA537 g was added to this precondensate.
, And heating and heating were started again. The temperature was raised sequentially while collecting the produced water, the reaction was continued at the maximum temperature of 235 ° C., and sampling was started when the CA crystals disappeared from the reaction system. Heating was stopped near the temperature at which the Gardner viscosity reached Z1, and the reaction product was transferred to a tin can of No. 4 and cooled and pulverized to obtain a polyesterimide resin. The recovered amount of generated water was 580 g.

Next, the polyesterimide resin obtained above was placed in another flask having a capacity of 2 and equipped with a stirrer, a thermometer and a cooling tube.
723 g, m-cresylic acid 465 g and SW1000 naphtha 104 g were charged, heated to 140 ° C., and uniformly dissolved and mixed. Then, the mixture was cooled to 100 ° C., and 48 g of a 50% by weight cresol solution of p-tert-butylphenol formaldehyde resin was added.
42 g of a 50% by weight cresol solution of PT and 54 g of Desmodur CT were added, and the mixture was uniformly dissolved and cooled. The mixture was cooled to 90 ° C. or lower, and filtered using a qualitative filter paper.
A polyester imide wire enamel having a viscosity of 65 poise at ° C was obtained.

The polyester imide wire enamel obtained in Examples and Reference Examples was obtained by using an electric furnace having an effective furnace length of 3 m and a central baking temperature of 430.
The coating was baked on a soft copper wire having a diameter of 1 mm at a temperature of 6 ° C. and a coating speed of 6.0 m / min. Table 1 shows the line performance measurement results. The polyester imide wire enamel of the present invention using cyanuric acid as the supply component of the isocyanurate bond in place of the polyhydric alcohol component THEIC has excellent characteristics comparable to the reference example using THEIC. I have.

(Effect of the Invention) From the characteristics of the polyesterimide wire in the examples, cyanuric acid and ethylene glycol are used in place of THEIC, and isocyanurate bonds are arranged in the molecular structure, so that heat-resistant polyesterimide wire enamel of comparable quality. Can be prepared. In addition, since inexpensive cyanuric acid and ethylene glycol are used without using expensive THEIC, the cost can be extremely reduced.
Furthermore, since cyanuric acid is used without using THEIC, a polyesterimide having a tris (hydroxy lower alkyl) isocyanurate structure corresponding to the glycol used in the reaction can be easily produced.

Claims (6)

(57) [Claims] (1) at least one glycol selected from the group consisting of cyanuric acid or an isomer thereof, ethylene glycol, propylene glycol and neopentyl glycol in the presence or absence of a solvent, dicarboxylic acid,
A method of producing a polyesterimide having an imidation ratio of 20 to 40% and having an isocyanurate bond in a molecular structure, characterized by reacting an aromatic tricarboxylic acid and / or an anhydride thereof and an aromatic diamine. 2. A precondensate obtained by previously reacting a glycol and a dicarboxylic acid with cyanuric acid or an isomer thereof,
The method for producing a polyesterimide according to claim 1, wherein an aromatic tricarboxylic acid and / or an anhydride thereof and an aromatic diamine are added and reacted by heating. 3. A precondensate obtained by reacting a glycol, a dicarboxylic acid, an aromatic tricarboxylic acid and / or an anhydride thereof, and an aromatic diamine in advance with cyanuric acid or an isomer thereof and reacting by heating. The method for producing a polyesterimide according to claim 1, wherein 4. Glycol is ethylene glycol, dicarboxylic acid is terephthalic acid, aromatic tricarboxylic acid and / or
Or the anhydride thereof is trimellitic anhydride and the aromatic diamine is 4,4'-diaminodiphenylmethane. The method for producing a polyesterimide according to any one of claims 1 to 3, wherein 5. At least one glycol selected from the group consisting of cyanuric acid or an isomer thereof, ethylene glycol, propylene glycol and neopentyl glycol, in the presence or absence of a solvent, dicarboxylic acid,
An aromatic tricarboxylic acid and / or an anhydride thereof and an aromatic diamine are reacted to obtain an imidation ratio of 20 to 40%.
And obtaining a polyesterimide having an isocyanurate bond in the molecular structure, and dissolving the polyesterimide in a solvent. 6. The method for producing a wire enamel according to claim 5, further comprising mixing a curing agent and / or a modifying agent.