JPS581686B2 - Heat resistant resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a heat-resistant resin composition mainly useful for electrical insulation.

Conventionally, compositions mainly composed of crosslinked terephthalic acid polyester have been used as low-cost insulating compositions for general-purpose electric wires.

However, when an electric wire insulated with this composition is incorporated into electrical equipment and used at high temperatures, it is impossible to satisfy thermal properties such as heat life, thermal shock resistance, and thermal softening temperature.

In recent years, there has been a strong demand for an electrically insulating composition that is more thermally stable than this crosslinked terephthalic acid polyester, and in response to this demand, various heat-resistant resin compositions have been proposed to date.

For example, electrical insulating compositions such as polyester using tris(2-hydroxyethyl) isocyanurate as an alcohol component, polyester-imide and polyester-amide-imide made by further modifying this polyester with imide or amide-imide are known. It is being

In addition, the inventors have developed a heat-resistant resin composition containing a novel polyester-amide-imide by first using a polyester consisting of an aromatic dicarboxylic acid or its ester derivative and a polyhydric alcohol of dihydric or higher valence. The molar ratio of tricarboxylic acid monoanhydride and primary diamine is 0.3 to
Modified with a polyamide-imide condensate with a ratio of 0.7/1,
This is further reacted with a modifying polyester having an acid value residual rate of 10 to 60% derived from an aromatic polycarboxylic acid component such as an aromatic polycarboxylic acid anhydride and a polyhydric alcohol of dihydrity or more. proposed a heat-resistant resin composition (hereinafter referred to as the prior application composition).

All of these compositions have superior thermal properties compared to those made of conventional crosslinked terephthalic acid polyesters,
It can greatly improve reliability when used under high temperatures, and in particular, the composition of the earlier application has a wider range of permissible baking conditions when coating electric wires, improving coating workability and improving the quality of the product. It has also been found that it has the advantage of being able to stabilize the thermal properties, mechanical, chemical, and electrical properties of the material.

On the other hand, these proposed compositions have the disadvantage of requiring a large amount of organic solvent to obtain a viscosity that allows coating on electric wires due to their resin content.

For example, according to the composition of the prior application mentioned above, there is a tendency that the amount of solvent can be reduced compared to other compositions, but it is still necessary to use about 50% by weight of the solvent in the entire composition, and if it is less than this, it is practically impossible. It becomes difficult to cover the wires.

Since the oil shock, the supply of petroleum-based raw materials has become increasingly difficult, and the use of such large amounts of solvents is not desirable in terms of resource conservation.

Furthermore, the need to increase the amount of solvent inevitably leads to a decrease in the resin solid content concentration, which affects the number of times of coating when coating electric wires, causing problems in coating workability and productivity.

The object of the present invention is not only to form a film having good mechanical, chemical and electrical properties and excellent thermal properties generally required for an electrically insulating composition, but also to provide The object of the present invention is to obtain a heat-resistant resin composition that has a viscosity that can be coated even when the amount of solvent is reduced, that is, a heat-resistant resin composition that has a high resin solid content concentration and a low viscosity.

As a result of intensive studies to achieve the above object, this invention further improves the composition of the prior application and uses a specific polyester, polyamide-imide condensate, and modified polyester in this composition. , when these are mixed without substantially reacting, or when mixed with the polyamide-imide condensate reacted with only one of the three components, the polyester or the modified polyester, the coating is possible. A very small amount of solvent is required to obtain the viscosity, and when the composition obtained by this method is finally treated at high temperature, it has good heat resistance properties and other properties that are almost comparable to those of the composition of the prior application. It was discovered that it was possible to form a film with

That is, this invention provides (a) a polyester whose main acid component is an aromatic dicarboxylic acid or an ester derivative thereof and which is derived from this and a polyhydric alcohol of dihydric or higher valence;
b) Aromatic tricarboxylic acid monoanhydride and primary diamine with the above anhydride/diamine (molar ratio) of 0.3 to 0.7.
A polyamide-imide condensate reacted at a ratio of /1, and (c) an aromatic polycarboxylic acid component such as an aromatic polycarboxylic acid anhydride and a polyhydric alcohol of dihydric or higher valence. Modifying polyester having an acid value residual rate of 10 to 60% without substantially reacting with each other, or (
This relates to a heat-resistant resin composition obtained by mixing either component (a) or component (c) with component (b) in a reacted state.

The acid component of the polyester as component (a) used in this invention is mainly aromatic dicarboxylic acid or its ester derivative, and these include terephthalic acid, isophthalic acid, penzophenone dicarboxylic acid or these. dicarboxylic acid and carbon number is 1 to 5
monoesters or diesters with alcohols or glycols.

Optionally, along with these dicarboxylic acids or their ester derivatives, small amounts (usually within the range of up to 20 mol% of the aromatic dicarboxylic acids or their ester derivatives) of aliphatic dicarboxylic acids or Its ester derivatives can also be used in combination.

Ester derivatives of aliphatic dicarboxylic acids include monoesters or diesters of alcohols or glycols having 1 to 5 carbon atoms.

The most desirable acid component is terephthalic acid or its ester derivative, and it is also preferable to use these together with up to 80 mol% of isontal acid or its ester derivative.

On the other hand, the alcohol component used is a polyhydric alcohol with a valence of more than 2, such as tris(2-hydroxyethyl).
trihydric alcohols such as incyanurate, glycerin, and trimethylolpropane, low molecular weight polyethylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol, 1,3-propanediol, 1,4-butadiol, 1. Dihydric alcohols such as 5-pentanediol, 1,6-hexanediol, and neopentyl glycol can be used.

The usage ratio of these polyhydric alcohols is generally determined by the total amount of hydroxyl groups (
equivalent) is a reactive acid group (carboquine group or ester group) of an aromatic dicarboxylic acid or its ester derivative
The ratio is usually 1.1 to 20 times, preferably 1.2 to 1.6 times.

In this invention, these polyester-forming components are generally used at a ring softening point (Japanese Industrial Standard JISK2531
-66 Measured value based on petroleum asphalt softening point test method (ring and ball method) Ring softening point means a similar measurement value of 70 to 130°C, preferably 90 to 120°C
of polyester.

If the polyester has a ring softening point that is too low, the final composition of the present invention will have poor film-forming ability and will tend to lack various properties such as mechanical strength, heat resistance, and flexibility when formed into a film. On the other hand, if the ring softening point becomes too high, there is a risk that the number of unreacted reactive acid groups will be very small, or that the appearance of the coating will be poor due to contamination of gel components due to excessive polymerization.

To synthesize such a polyester, it is sufficient to heat the acid component and the alcohol component to react at a temperature of usually 150 to 230°C until the ring softening point reaches 70 to 130°C, and the reaction time is For the purpose of shortening the reaction time, the reaction may be carried out under reduced pressure when the ring softening point reaches 45 to 65°C.

In addition, zinc acetate, manganese acetate, lead acetate,
Metal salts of acetic acid such as copper acetate, alkyl titanates, and metal salts of octenoic acid, naphthenic acid or lauric acid can also be used.

A solvent is usually not required, but when it is used, it is preferably used within a range that provides a concentration of up to 70% by weight of the polyester-forming component.

The polyamide-imide condensate as component (b) used in this invention consists of an aromatic tricarboxylic acid monoanhydride represented by trimellitic anhydride and a primary diamine, and Anhydrides are much cheaper than aromatic tetracarboxylic dianhydrides such as pyromellitic acid, and special and expensive solvents such as N-methylpyrrolidone, dimethylacetamide, dimethylformamide, etc. can be used as solvents for polymers. This has the advantage that general-purpose solvents such as cresol and phenol can be used without the need for special solvents.

The primary diamine may be either an aliphatic diamine or an aromatic diamine, or a combination of both, but it is preferable to use an aromatic diamine from the viewpoint of improving heat resistance.

Aromatic diamines include metaphenylene diamine, paraphenylene diamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ethane, 4,4'
-Cyaminodiphenylpropane, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, benzidine, 3,3'-dimethoxybenzidine,
4,4'-diaminodiphenyl sulfide, 4,4'-
Diaminodiphenyl sulfone, parabis(4-aminophenoxy)benzene, parabis(4-aminophenoxy)benzene, metabis(4-aminophenoxy)
Examples include benzene, 4,4'-diaminobiphenyl, metaxylene diamine, and paraxylene diamine.

Examples of the aliphatic diamine include ethylene diamine, trimethylene diamine, tetramethylene diamine, pentamethylene diamine, and hexamethylene diamine.

In this invention, the molar ratio of the aromatic tricarboxylic acid monoanhydride and the primary diamine is such that the anhydride/diamine ratio is 0.3 to 0.7/1, preferably 0.45 to 0.60.
It is important to set the ratio to be /1.

According to this molar ratio, a polyamide-imide condensate having amine groups at both ends of the molecule is mainly produced.

This condensate generally has a low degree of condensation (the average molecular weight per amino group located at the terminal is usually 125 to 1300).
) and has amine groups at both ends of the molecule, so when the composition of the present invention is produced by reacting with the above-mentioned polyester, it is relatively easy to react with the reactive acid groups of this polyester. can be done.

In addition, if such a reaction is not carried out during the production stage, good results can be obtained in terms of solubility in polyester.

On the other hand, if the anhydride/diamine ratio is set to a molar ratio exceeding 0.7/1, for example, a molar ratio of about 0.8 to 1.2/1 as found in primary amide-imide modified polyesters, , a polyamide-imide condensate having a carboxyl group and an amine group at both ends is mainly produced by condensation polymerization at a ratio of 1 mole of diamine to 1 mole of anhydride, and this condensate generally has a degree of condensation. This is not preferable because the polymer has a very high molecular weight, that is, the average molecular weight per amine group located at the end is about 1,500 to 2,900, and the solubility and reactivity with respect to the polyester decreases.

In addition, the anhydride/diamine ratio can be further increased to, for example, about 2/diamine as found in general imide-modified polyester.
When the molar ratio is approximately 1, 1 mole of diamine is condensed to 2 moles of anhydride, resulting in a polyimide condensate with carboxyl groups at both ends and no or almost no amide bonds in the molecule. Primarily generated.

As mentioned above, this condensate has poor solubility in polyester, and even when reacted with polyester, only ester bonds are introduced during the reaction, and amide bonds, which contribute to improving heat resistance, cannot be introduced. Since the imide bonds contained in the polyamide condensate are mainly introduced, it is necessary to use large amounts of expensive solvents such as N-methylpyrrolidone and dimethylacetamide, and in any case, the composition The intended purpose of reducing the solids content of the product cannot be achieved.

On the other hand, if the anhydride/diamine ratio is smaller than 0.3/1, it may cause thermal deterioration of the film after baking of the composition of the present invention, resulting in disadvantages such as a significant decrease in thermal properties, especially heating life. let

Thus, in this invention, the anhydride/diamine ratio is set to 0.
The ratio of 3 to 0.7/1 is set to a low molecular weight polyamide having amine groups at both ends, which has relatively excellent solubility in polyester and reactivity with reactive acid groups contained in this polyester. This is because imide condensates are mainly formed.

In order to synthesize such a polyamide-imide condensate in the present invention, an aromatic tricarboxylic anhydride and a primary diamine are generally used together with an appropriate organic solvent such as phenol or cresol, and an azeotropic solvent such as xylene or naphtha. What is necessary is just to mix it and heat-react this at the temperature of 120-210 degreeC until the reaction product water no longer distills out.

After this reaction, the remaining azeotropic solvent is distilled off to obtain the low molecular weight polyamide-imide condensate having amino groups at both ends.

In this invention, especially when adopting a form in which such a polyamide-imide condensate and the above-mentioned polyester are reacted, the reactivity between the aromatic tricarboxylic acid anhydride and the primary diamine is extremely high. Alternatively, a method may be adopted in which a polyamide-imide forming component is added to the aforementioned polyester synthesis system and the required condensate is produced within this system.

In this case, the condensate produced can be reacted sequentially into polyester, which is an industrially advantageous method.

The modified polyester as the component (c) used in this invention is derived from an aromatic polycarboxylic acid component such as an aromatic polycarboxylic acid anhydride and a polyhydric alcohol of dihydric or higher valence. 10 to 60%, preferably 30 to 50%, and generally consists of a polyester with a low degree of condensation containing monoesters, diesters, triesters, etc. of aromatic polyhydric carboxylic acid components,
In some cases, some unreacted polyhydric alcohol is also included.

The purpose of using this modifying polyester is to ensure that the polyamide-imide condensate has amine groups at both ends, and usually has an excess of amine groups in order to sufficiently modify the high molecular weight polyester. Therefore, when a composition consisting only of this condensate and the above-mentioned polyester is finally heat-treated at a high temperature to form a heat-resistant film, free amino groups generally tend to remain and the film deteriorates. The purpose is to avoid this drawback, that is, to reliably convert the above-mentioned free amine groups into amide bonds and imide bonds using the modifying polyester.

It is also possible to use an acid component such as an aromatic polycarboxylic acid anhydride alone instead of such a modifying polyester, but in this case, the reactivity with free amine groups is poor, and the above-mentioned The reaction with hydroxyl groups contained in high molecular weight polyester cannot be ignored, and it is also disadvantageous in terms of the molecular chain length of the polyester-amide-imide that is finally formed, and unreacted acid components remain. There is a large risk that it will cause a loss of adhesion and slipperiness to the copper wire when formed into a coating.

The polyester for modification of the present invention is very advantageous in these respects, and in particular, the reactivity toward amino groups of the condensate is higher than that of the acid component alone, or the aromatic dicarboxylic acid or its ester derivative as the component (a) described above. It has a high molecular weight compared to polyester, which has a sufficiently high molecular weight to satisfy various properties such as flexibility derived from dihydric or higher polyhydric alcohols, and this feature makes it possible to fully achieve the above purpose of use. be.

On the other hand, it is necessary for such a polyester for modification to have an acid value residual rate in the range of 10 to 60%, and polyesters that deviate from this range will cause various problems.

In other words, polyester with an acid value residual rate of less than 10% becomes a polymer with a high degree of condensation, and its reactivity with amine groups is extremely reduced, resulting in poor thermal properties such as thermal shock resistance and thermal deterioration wrapability. It will no longer contribute to improvement.

On the other hand, in a polyester with a content of more than 60%, the number of free carboxyl groups increases, and in addition to the reaction with amino groups, the esterification reaction with the hydroxyl groups contained in the polyester proceeds at the same time. It is not possible to lead the group preferentially into an amide bond or an imide bond, resulting in a decrease in thermal properties such as thermal softening temperature.

In this specification, the acid value residual rate refers to the acid value before and after esterification (assuming the acid anhydride group is difunctional), and when the acid value before esterification is Avo and the acid value after esterification is Avs, Avs /Avo×100 (%).

The aromatic polycarboxylic acid components used in the modified polyester include aromatic dicarboxylic acid anhydrides such as phthalic anhydride, aromatic tricarboxylic acid monoanhydrides such as trimellitic anhydride, and pyromellitic dianhydride. compound, benzophenonetetracarboxylic dianhydride, naphthalene-2
・3,6,7-tetracarboxylic dianhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, diphenyl-2,3,2',3'-tetracarboxylic dianhydride, 2,2-bis(3',4'-dicarboxyphenyl)
Aromatic tetracarboxylic acids such as propanetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)sulfonetetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride There are dianhydrides and the like, and free carboxylic acids corresponding to the above-mentioned anhydrides can also be used in some cases.

Among these acid components, one or two tri- or tetracarboxylic acid anhydrides or corresponding free carboxylic acids that can lead a free amino group to an imide bond together with or in place of an amide bond are preferably used.
Use more than one species.

It is also preferable to use aromatic tricarboxylic acid monoanhydride, which is relatively inexpensive, alone or together with the above-mentioned anhydride for the purpose of improving thermal shock resistance, solvent resistance, flexibility, etc. It is preferable to use up to 50 mol% of aromatic dicarboxylic anhydride, aromatic tetracarboxylic dianhydride, or the corresponding free carboxylic acid.

Examples of polyhydric alcohols of dihydric or higher type used in the modified polyester include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentadiol, 1, Dihydric alcohols such as 6-hexanediol and neopentyl glycol, glycerin, trimethylolpropane, and tris(
Examples include trihydric alcohols such as 2-hydroxyether) isocyanurate.

In the synthesis of polyester for modification, the above-mentioned aromatic polycarboxylic acid component and polyhydric alcohol are usually mixed at 100 to 200%
The reaction may be carried out by heating at a temperature of .degree. C. until the desired acid value residual rate is obtained.

Of course, the reaction proceeds even at temperatures lower than 100°C, but in this case the reaction time must be increased.

At the temperature of 100 to 200℃ mentioned above, it is generally 0.5 to 200℃.
The reaction is complete in 48 hours.

Particularly desirable reaction conditions are 130 to 160°C.
It is best to select conditions for ~24 hours.

The ratio of the polyhydric alcohol and the aromatic polycarboxylic acid component used in this reaction is such that the amount of hydroxyl groups is equivalent or more to the carboxyl group (in the case of anhydrous acid group, it is calculated as a difunctional group) of the acid component, usually 1 to 1. The ratio should preferably be 5 times the amount, preferably 2 to 3 times the amount.If the amount of hydroxyl groups is less than the amount of carboxyl groups and there are many carboxyl groups that are not esterified, the reaction will occur rather than reacting with the amine group. The esterification reaction with the hydroxyl groups contained in the polyester tends to proceed, making it difficult to achieve the main purpose of modifying free amine groups.

In this invention, the above-mentioned polyester as component (a), polyamide-imide condensate as component (b), and modifying polyester as component (c) are used without reacting with each other, or with polyester or The polyamide-imide condensate is reacted with one of the modified polyesters and then mixed, and the mixing ratio of the three components is as follows.

The mixing ratio of the polyester as the component (a) and the polyamide-imide condensate as the component (b) varies depending on the degree of heat resistance required for electrical insulation. Better heat resistance properties can be obtained by increasing the amount of the polyamide-imide condensate to 100 parts by weight of polyester, but it is generally preferable that the amount of the polyamide-imide condensate be 10 to 300 parts by weight, preferably 50 to 150 parts by weight. .

If the amount of condensate is too small, the heat resistance level will be low, while if it is too large, it will become expensive and industrially disadvantageous.

Furthermore, considering the purpose of use of the modifying polyester as component (c), the reactive acid groups (mainly The active ester group at the end of the polyester is preferably used in an amount equal to or more than the equivalent amount, usually 1.4 to 8.4 times, preferably 2 to 4 times, but it is necessary to determine such a quantitative ratio. It is not easy at all.

According to the findings of the inventors, when an aromatic tricarboxylic acid component such as aromatic tricarboxylic acid monoanhydride is used to form a modified polyester, this acid component and the polyamide-imide condensate are usually synthesized. It has been found that a molar ratio of about 1:1 to about 2:1 with respect to the primary diamine used provides good results in improving thermal properties.

On the other hand, if the acid component such as anhydride is too small or too large, the thermal properties such as thermal shock resistance, thermal deterioration wrapability, and heating life will deteriorate due to the presence of free amino groups. There is a tendency for similar deterioration of thermal properties due to deterioration or the presence of excess modifying polyester, both of which are undesirable.

Next, regarding the means for mixing the three components, first of all, if the three components are not to substantially react with each other, it is preferable to use normal mixing means generally known in the industry to avoid excessive mixing that hardly causes any reaction. What is necessary is to uniformly dissolve and mix them under heating.

This unreacted mixing has the advantage of increasing the resin solid content concentration to achieve a coating-enabled viscosity.

Also, among the three components, polyester as component (a) and component (b)
When reacting with a polyamide-imide condensate as a component, the temperature of both is usually 100°C or higher, preferably 180°C or higher.
The time until the reaction product (water or alcohol) is no longer extracted at a temperature of 230°C, generally 0.5 to 8 hours, preferably 1 to 5 hours, particularly preferably 1.5 to 3 hours
The reaction may be carried out by heating for a certain period of time.

In addition, when adopting such a reaction form and adding a polyamide-imide forming component to the polyester synthesis system as described above and reacting continuously following the polyester production reaction and condensate production reaction, the reaction conditions are the same as above. It's the same.

Furthermore, when reacting the modifying polyester as component (c) of the three components with the polyamide-imide condensate as component (b), the two are usually reacted at a temperature of 100°C or higher, preferably 180 to 230°C. The time until the product (water or polyhydric alcohol) stops distilling out, generally 0
．． The reaction may be carried out by heating for 5 to 8 hours, preferably 1 to 3 hours.

In this way, when either component (a) or component (e) is reacted with component (b) and mixed, the mixed composition contains an intermediate consisting of polyester-amide-imide. It's coming.

This intermediate provides better results in improving various properties such as flexibility and heat resistance of the coating than when the three components are mixed in an unreacted state.

Note that the components (c) to (a) that are not involved in the reaction are mixed by a conventional mixing means after the above-mentioned mixing reaction.

As described above, in this invention, by adopting an embodiment in which the three components are not allowed to react with each other, a very high resin solid content concentration can be obtained, and in addition, either one of component (a) or component (c), especially (c) Since better results can be obtained in terms of film properties by adopting an embodiment in which component (b) is reacted and mixed with the components, an appropriate embodiment may be selected depending on the purpose of use.

On the other hand, when obtaining the composition of this invention, component (a) and (c)
Reaction with component (e) would defeat the original purpose of component (e), so this reaction must be avoided.

Also, as is clear, (a) and (b) like the composition of the earlier application
, (c) When each component is reacted, the amount of solvent required to obtain a coatable viscosity increases, resulting in a decrease in the resin solid content concentration.

The heat-resistant resin composition of the present invention is made by mixing polyester, polyamide-imide condensate, and modified polyester by such a method, and a curing agent that is usually applied to general heat-resistant polyester is added to the composition. For example, organic titanium compounds, typified by tetraalkyl titanates whose alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc., can be added alone or in combination. .

The amount of this curing agent used is usually 0.5 to 10% by weight, preferably 3 to 7% by weight, based on the resin solid content in the composition.

Further, a curing accelerator can be added together with the above curing agent as necessary.

Effective curing accelerators for organic titanium compounds include metal salts of octenoic acid, naphthenic acid, or lauric acid such as calcium, manganese, iron, cobalt, nickel, copper, zinc, tin, and lead. One type or a combination of two or more types can be used.

The amount used may be within the range of 0.01 to 5% by weight based on the solid content of the resin.

Furthermore, the heat-resistant resin composition of the present invention usually contains various optional components in order to improve various properties when formed into a film.
It can be contained in an amount of ~40% by weight, preferably 3-30% by weight, and representative optional components include blocked isocyanates, polyincyanates, which are a type of resin solid content, phenolic resins, leveling agents, etc. It will be done.

Blocked isocyanates and polyisocyanates are added to the composition under heating to form polyester-
It shows activity on the functional groups remaining in the amide-imide and has the function of modifying it into a more effective polymer.

A specific example of blocked incyanate is 2.4-(
and 26-) tolylene diisocyanate in a cresol block or trimethylolpropane block, and metaphenylene diisocyanate or diphenylmethane diisocyanate in a xylenolic acid block. 6-) Trimer of tolylene diisocyanate and the like.

These blocked isocyanates and polyisocyanates are usually used in an amount of 1 to 20% by weight, preferably 3 to 1% by weight based on the resin solid content.
It may be used in a proportion of 0% by weight.

Phenolic resins are produced by addition condensation of phenols such as phenol, ortho-, meta- or para-coordinated cresol, meta- and para-coordinated cresol mixtures, ortho-, meta- or para-coordinated alkyl-substituted phenols, and phenols such as cresylic acid with formaldehyde. These are usually 1 to 20% by weight, preferably 3 to 10% by weight in the resin solid content.
It may be added preferably without heating.

The heat-resistant resin composition of the present invention produced in this manner generally contains the organic solvent used in its production stage, particularly during the synthesis of the polyamide-imide condensate, and often exhibits a viscosity that allows it to be coated as is. However, if necessary, a considerable amount of organic solvent may be added to adjust the resin solid content to an appropriate concentration.

As the organic solvent in this invention, general-purpose solvents such as ortho-cresol, meta-cresol, para-cresol, mixtures of meta- and para-cresol, phenol, and cresylic acid can be used, and in addition to these solvents, toluene and xylene can be used as diluents. It is also possible to use aromatic high-boiling naphthas and the like.

It goes without saying that polar solvents such as N-methyl-2-pyrrolidone, N.N'-dimethylacetamide, and N.N'-dimethylformamide can be used alone or in combination with the above-mentioned general-purpose solvents.

As detailed above, the heat-resistant resin composition of the present invention is
It is made by mixing a specific polyester, a polyamide-imide condensate, and a modified polyester using a specific method, and it has excellent thermal properties and mechanical properties that are almost comparable to the composition of the prior application. Not only can a film with various properties such as chemical and electrical properties be formed, but also the viscosity can be made to be easily coated even when the amount of organic solvent used is smaller than that of the prior application composition or other proposed compositions. In addition to being very advantageous in terms of resource conservation, the solid content of the resin can be increased to about 70% by weight or more, leading to a reduction in the number of times of coating when coating electric wires, improving workability and productivity. It has the advantage of greatly improving the

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A polyester, a polyamide-imide condensate, and a modified polyester were each synthesized by the following methods.

<Polyester> In a 3-liter three-necked flask equipped with a thermometer, steam cooler, and stirring device, 992.0 g (6.0 mol) of terephthalic acid, 414.0 g of glycerin, and 1 mol of ethylene glycol were added.
1.6 g (1.8 mol) was added and rapidly heated to 150°C.

At this time, 7.0% calcium acetate was used as an esterification catalyst.
8g was added, and then the temperature was raised to 200°C for 3 hours.

After heating and stirring at 200° C. for 1 hour, the system became a pale yellow transparent homogeneous system.

Subsequently, the temperature was gradually raised to 230°C until the reaction system became viscous to proceed with the esterification reaction, and the ring softening point reached 95.
The reaction was stopped when the temperature reached ℃.

By-product (distilled water) up to this point was 207.0 g.

<Polyamide-imide condensate> 576.0 g of trimellitic anhydride (3
．． 0 mol), 4,4-diaminodiphenylmethane 118
8.0 g (6.0 mol), 1200.0 g of a meta- and para-cresol mixture, and 66.0 g of xylene were added and rapidly heated to 120° C. under a nitrogen stream.

At 120°C, the reaction system begins to become reddish-orange turbid, but at 20°C
When the temperature was raised to 0° C. over 2 hours, the system became red and uniformly transparent.

The reaction was stopped when 93.0 g of reaction product water was distilled out,
The xylene was then distilled off.

The time required during this time was 3 hours.

The residual amino groups in the obtained polyamide-imide condensate were determined to be 49.3% of the initial concentration by a quantitative method using perchloric acid.

The quantitative method using perchloric acid is titration with perchloric acid using a mixture of meta and para-cresol as a solvent.
In this titration, both indicator titration and potentiometric titration using crystal violet as an indicator can be employed, but the former indicator titration method was employed here.

<Polyester for modification> 576.0 g of trimellitic anhydride (3
．． 0 mol) and 558 g (9.0 mol) of ethylene glycol were added, and the reaction was terminated by heating and stirring at 160° C. for 2 hours.

The acid value of the obtained modified polyester was 180, corresponding to an acid value residual rate of 40.5%.

Next, a heat-resistant resin composition of the present invention was obtained by the following operations using the three components synthesized by the above method.

First, a 3L unit equipped with a thermometer, a cooler with a side tube, and a stirring device.
307 g of polyester and 476 g of polyamide-imide condensate (solution containing meta and para-cresol) (the ratio of both used is 100 g of polyester)
(equivalent to 90 parts by weight of polyamide-imide condensate), and to this, 56 parts by weight of polyester for modification was added.
7 g (corresponding to a molar ratio of trimellitic anhydride used in this polyester and primary diamine used in the polyamide-imide condensate of 1.5:1),
The mixture was stirred and mixed at 0°C for 1 hour.

Thereafter, 240 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabuter titanate was gradually added dropwise to obtain a heat-resistant resin composition of the present invention.

The resin solid content concentration of this composition was 71.7% by weight, and the viscosity was 75 poise (30°C).

Example 2 A heat-resistant resin composition of the present invention was prepared by the following operations using the polyester synthesized by the method described in Example 1, a polyamide-imide condensate (a solution containing meta- and para-cresol), and a modifying polyester. I got it.

First, a 3L unit equipped with a thermometer, a cooler with a side pipe, and a stirring device.
218 g of polyester and 476 g of polyamide-imide condensate (the ratio of both is 12 parts by weight of polyamide-imide condensate to 100 parts by weight of polyester).
This was heated and stirred at 200° C. for 2 minutes to react, and then cooled to 70° C., 567 g of the modified polyester was added, and the mixture was stirred and mixed at 70° C. for 1 hour.

Thereafter, 220 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabutyl titanate was gradually added dropwise to obtain a heat-resistant resin composition of the present invention.

The resin solid content concentration of this composition was 67.9% by weight, and the viscosity was 80 poise (30°C).

Example 3 Using the polyester synthesized by the method described in Example 1, a polyamide-imide condensate (a solution containing meta- and para-cresol), and a modified polyester, a heat-resistant resin composition of the present invention was prepared by the following operations. I got it.

First, a 3L unit equipped with a thermometer, a cooler with a side tube, and a stirring device.
Polyamide-imide condensate 476 in a three-necked flask.
1 and 567 g of modified polyester were added, and the mixture was heated and reacted at 220° C. for 2 hours.

Next, this was cooled to 70°C, and 218 g of polyester was mixed and dissolved.

Thereafter, 220 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabutyl titanate was gradually added dropwise to obtain a heat-resistant resin composition of the present invention.

The resin solid content concentration of this composition was 68.3% by weight, and the viscosity was 82 poise (30°C).

This composition is exactly the same as Example 2 with respect to the amounts of polyester, polyamide-imide condensate, modifying polyester, and tetrabutyl tignate solution used.

Comparative Example 1 Using the same amounts of the polyester polyamide-imide condensate (solution containing meta- and para-cresol) synthesized by the method described in Example 1 and the modifying polyester as in Example 1, heat resistance was determined by the following procedure. A resin composition was made.

First, 307 g of polyester and 476 g of polyamide-imide condensate were added to the same three-necked flask as in Example 1, and the mixture was heated and reacted at 180°C for 2 hours. Next, 567 g of polyester for modification was added and heated at 200°C for 3 hours. Made it react.

Add 70% of the meta- and para-cresol mixture to this reaction solution.
0 g was added, and the system was cooled until the temperature within the system reached 60°C.

Thereafter, 240 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabutyl titanate was gradually added dropwise to obtain a heat-resistant resin composition.

The resin solid content concentration of this composition was 44.9% by weight, and the viscosity was 50 poise (30°C).

On the other hand, when preparing the above composition, if 700 g of the meta- and para-cresol mixture is not added after heating the modifying polyester, the viscosity of the reaction solution after cooling becomes very high, and tetrabutyl tetanate is added to the reaction solution after cooling. Even if one were to drop 240 g of the above solution, it would take a long time to mix, and the viscosity of the composition thus obtained was 3.
500 poise (at 30° C.), making it difficult to apply to wire coatings.

Comparative Example 2 The polyester synthesized by the method described in Example 1, the polyamide-imide condensate (liquid containing meta- and para-cresol), and the modified polyester were synthesized in Example 2 and
3 was used in the same amount as Comparative Example 1, and the resin solid concentration was 43.2% by weight and the viscosity was 47 poise (30°C).
A heat-resistant resin composition was prepared.

Note that 20% by weight of tetrabuter titanate added after the reaction.
The amount of meta and para-cresol mixture solution used is 2
The weight was 20g.

On the other hand, when preparing the above composition, when 700 g of the meta- and para-cresol mixture was not added after heating the modifying polyester, the result was the same as that described in Comparative Example 1, and the low It was not possible to obtain a viscosity composition.

Using each of the heat-resistant resin compositions obtained in Examples 1 to 3 and Comparative Examples 1 and 2 above, a vertical hot-air baking furnace with a furnace length of 3 m was used at a furnace temperature of 420°C and a linear speed of 6 m/min. The coating was applied to a copper wire with a core wire diameter of 1.0 mm under the following conditions and baked to obtain a coated wire.

Although the compositions of Examples 1 to 3 were applied three times,
The compositions of Comparative Examples 1 and 2 were applied 6 times.

This is because in Comparative Examples 1 and 2, when the number of applications was three times, the resulting coating had a foamed structure and was non-uniform in thickness, resulting in a very poor appearance and could not be used as a product.

The results of examining various properties such as flexibility and heat resistance of the coated wire thus obtained are shown in Table 1 below.

In the table, d indicates the double diameter of the wire, for example, 2d means 2
This means that the magnification is good.

As is clear from the above table, with the compositions with high resin solid content concentrations according to Examples 1 to 3, results almost comparable to those of Comparative Examples 1 and 2 were obtained even if the number of applications was reduced. I know that there is.

Example 4 Using a polyester synthesized by the method described in Example 1 and a polyamide-imide condensate (a solution containing meta and para-cresol), and using a modified polyester synthesized by the following method, A heat-resistant resin composition of the present invention was prepared in the following manner.

<Polyester for modification> In a three-necked flask similar to Example 1, 576 g (3.0 mol) of trimellitic anhydride and 372 g of ethylene glycol were added.
g (6.0 mol) and tris(2-hydroxyethyl)in cyanurate 548 g (2.1 mol) were added, and 1
The reaction was stopped by heating and stirring at 60° C. for 2 hours.

The acid value of the obtained modified polyester was 135, corresponding to an acid value residual rate of 40%.

Next, 307 g of polyester and 476 g of polyamide-imide condensate were added to the same three-necked flask as in Example 1.
In addition to this, 749 g of the modified polyester produced by the above method (corresponding to a molar ratio of trimellitic anhydride used in this polyester and primary diamine used in the polyamide-imide condensate was 1.5:1) ) and stirred and mixed at 70°C for 1 hour.

Thereafter, 250 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabutyl titanate was gradually added dropwise to obtain a heat-resistant resin composition of the present invention.

The resin solid content concentration of this composition was 75.2% by weight, and the viscosity was 80 poise (30°C).

Example 5 Using the polyester and polyamide-imide condensate (solution containing meta- and para-cresol) synthesized by the method described in Example 1, and the modified polyester synthesized by the method described in Example 4, A heat-resistant resin composition of the present invention was prepared in the following manner.

First, 218 g of polyester and 476 g of polyamide-imide condensate were added to the same three-necked flask as in Example 1, and the mixture was heated and stirred at 200°C for 2 hours to react. After cooling to 70°C, 749 g of polyester was added and mixed with stirring at 70° C. for 1 hour.

Thereafter, 264 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabuter titanate was gradually added dropwise to obtain a heat-resistant resin composition of the present invention.

The resin solid content concentration of this composition was 681% by weight, and the viscosity was 8.
The temperature was 2 poise (30°C).

Example 6 Using a polyester synthesized by the method described in Example 1, a polyamide-imide condensate (a solution containing meta and para-cresol), and a modified polyester synthesized by the method described in Example 4, A heat-resistant resin composition of the present invention was prepared in the following manner.

First, 476 g of polyamide-imide condensate and 749 g of modified polyester were placed in a three-necked flask similar to that in Example 1, and the mixture was heated and reacted at 220° C. for 2 hours.

Next, this was cooled to 70°C, and 218 g of polyester was mixed and dissolved.

Thereafter, 264 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabutyl titanate was gradually added dropwise to obtain a heat-resistant resin composition of the present invention.

The resin solid content concentration of this composition was 69.5% by weight, and the viscosity was 81 poise (30°C).

Comparative Example 3 The polyester and polyamide-imide condensate (solution containing meta- and para-cresol) synthesized by the method described in Example 1 and the modified polyester synthesized by the method described in Example 4 were tested. A heat-resistant resin composition was prepared using the same amount as in Example 4 and the following operations.

First, 307 g of polyester and 476 g of polyamide-imide condensate were added to the same three-neck flask as in Example 1, and the mixture was heated and reacted at 180°C for 2 hours. Next, 749 g of polyester for modification was added and heated at 220°C for 1 hour. The reaction was carried out by heating.

Add 70% of the meta- and para-cresol mixture to this reaction solution.
0 g was added, and the system was cooled until the temperature within the system reached 60°C.

Thereafter, 250 g of a meta- and para-cresol mixture solution containing 20% by weight of tetrabutyl titanate was gradually added dropwise to obtain a heat-resistant resin composition.

The resin solid content concentration of this composition was 49.2% by weight, and the viscosity was 61 poise (30°C).

On the other hand, when preparing the above composition, if 700 g of the meta- and para-cresol mixture is not added after heating the modifying polyester, the viscosity of the reaction solution after cooling becomes very high, and the viscosity of the reaction solution becomes very high, and the viscosity of the reaction solution after cooling becomes very high. Even if one were to drop 240 g of the solution, it would take a long time to mix, and the viscosity of the composition thus obtained was 4.
000 poise (at 30° C.), making it difficult to apply to electric wire coatings.

Comparative Example 4 The polyester and polyamide-imide condensate (solution containing meta- and para-cresol) synthesized by the method described in Example 1 and the modified polyester synthesized by the method described in Example 4 were tested. A heat-resistant resin composition having a resin solid concentration of 45.7% by weight and a viscosity of 49 poise (30° C.) was prepared using the same amount as in Examples 5 and 6 and the same operation as in Comparative Example 3.

The heating reaction conditions for the modified polyester are 220℃ and 2
The amount of the meta- and para-cresol mixture solution containing 20% by weight of tetrabutyl titanate added after the reaction was 264 g.

On the other hand, when preparing the above composition, when 700 g of the meta- and para-cresol mixture was not added after heating the modifying polyester, the result was the same as that described in Comparative Example 3, and the low It was not possible to obtain a viscosity composition.

Using each of the heat-resistant resin compositions obtained in Examples 4 to 6 and Comparative Examples 3 and 4 above, coated electric wires were prepared in the same manner as in Examples 1 to 3 and Comparative Examples 1 and 2 described above. Obtained.

Although the compositions of Examples 4 to 6 were applied three times,
In Comparative Examples 3 and 4, the number of applications was 6 times.

This is due to the same reason as in Comparative Examples 1 and 2 above.

The results of examining the characteristics of the coated wire thus obtained are shown in Table 2 below.

From this table, it can be seen that the same good results as Examples 1-3 were obtained even with the compositions of Examples 4-6 with high resin solid content concentrations.

Claims (1)

[Scope of Claims] 1(a) A polyester whose main acid component is an aromatic dicarboxylic acid or its ester derivative and which is derived from this and a polyhydric alcohol of dihydric or higher valence; and (b) an aromatic tricarboxylic acid monoanhydride. and the primary diamine in an anhydride/diamine (molar ratio) of 0.3 to
A polyamide-imide condensate reacted at a ratio of 0.7/1; (C) an aromatic polycarboxylic acid component such as an aromatic polycarboxylic acid anhydride and a dihydric or higher polyhydric alcohol; A modified polyester having an induced acid value residual rate of 10 to 60% is substantially not reacted with each other, or component (b) is added to either component (a) or component (c). A heat-resistant resin composition obtained by mixing in a reacted state.