JP3192695B2 - Coating material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating solution for coating a solution used for coating wires such as electric wires and wires, and a coating method.

[0002]

2. Description of the Related Art Hitherto, a method of coating a wire such as an electric wire and a wire by applying a polymer solution and drying and removing a solvent has been used to obtain a coating film. However, it is generally difficult to make a concentrated solution of a polymer,
It must be heated or take a long time. Moreover,
Concentrated solutions of polymers have high viscosity and are difficult to handle. On the other hand, when the concentration is lowered, the preparation of the solution becomes easier and the handling becomes easier. On the other hand, in order to obtain a desired film thickness, it is necessary to repeat the application and drying many times to recoat.

As a result of intensive studies to solve such a problem, the present inventor has used a resin which has a relatively low molecular weight as a coating material, but is easily repolymerized by heating to become a high molecular weight. Thus, they have found that the present invention can solve the problem, and have completed the present invention.

[0004]

That is, the present invention provides a method of
A coating material solution containing, as a coating material, a polyamide having a relative viscosity of 0.5% meta-cresol solution at 5 ° C. of 1.8 or less, wherein the content molar ratio between terminal carboxyl groups and terminal amino groups in the solution is plural. 1: 4 to 4: 1 by the combined use of polyamide or the addition of diamine or dicarboxylic acid
To provide a coating material solution for solution coating, which is adjusted to the range described above. The present invention also provides a coating method, wherein the coating material solution is applied to a coating substrate, and the coating material is repolymerized by heating.

The polyamide used in the present invention includes nylon 6, nylon 66, nylon 11, nylon 12, and copolymers thereof. Further, the polyamide used in the present invention preferably has a relative viscosity of 0.5% meta-cresol solution at 25 ° C. of 1.8 or less. If the relative viscosity of the 0.5% meta-cresol solution at 25 ° C. is higher than 1.8, it becomes difficult to prepare a concentrated solution, and the solution viscosity also becomes high, resulting in a decrease in workability.

On the other hand, the molar ratio of the terminal carboxyl group to the terminal amino group in the solution is desirably 1: 1. However, since the terminal group having a smaller content is polymerized until the terminal group is completely reacted, the molar ratio is increased. The ratio may be in the range of 1: 4 to 4: 1. That is, a solution of a polyamide in which one end of a molecular chain is a carboxyl group and a multi-end is an amino group is most preferable, but a polyamide in which both ends of a molecular chain are a carboxyl group and a polyamide in which both ends of a molecular chain are an amino group are in the above range. Or a polyamide and a diamine having carboxyl groups at both ends of the molecular chain, or a polyamide and dicarboxylic acid having amino groups at both ends of the molecular chain in the above-described range of the functional group content. May be adjusted.
However, monoamines and monocarboxylic acids cannot be used for the purpose of the present invention because they do not contribute to the progress of polymerization. Further, when the content ratio of the terminal functional group is out of the above range,
A smaller amount is not preferred because the molecular weight does not increase until it has sufficient strength even if the polymerization is carried out until the reaction is completed. Further, a catalyst such as phosphoric acid may be added to increase the speed of repolymerization.

[0007] The coating method using the coating material of the present invention comprises:
The coating material is dissolved in an alcohol such as methanol, ethanol, or isopropanol and a mixed solvent obtained by adding a halogenated hydrocarbon such as trichlene thereto, or an appropriate solvent such as meta-cresol to prepare a coating material solution. The coating material concentration in the solution depends on the molecular weight of the polyamide used, but is preferably in the range of 1 to 20% by weight. Below 1% by weight, the viscosity of the coating material solution is low,
The workability of coating is good, but in order to obtain a desired film thickness, repeated coating and drying are required to be repeated. On the other hand, when the content is 20% by weight or more, the viscosity of the coating material solution is too high, so that handling such as dissolution and application becomes difficult.

Next, the coating material solution is applied to a coating substrate, and the solvent is removed by drying to obtain a polyamide coating film. By heating during the drying step or heating after the drying step,
The polyamide coating film is re-polymerized into a coating film having a high molecular weight and sufficient strength. The heating temperature for repolymerization is slightly different depending on the type of polyamide,
In the temperature range of 5 to 5 hours, the repolymerization is sufficiently performed.
A range of 60 minutes is preferred. The present invention provides an electric wire, a wire,
Any coating substrate, such as a metal plate, that can withstand heating during repolymerization can be applied to any substrate. However, when a reheating step is performed after coating such as a fused wire, a greater effect can be expected.

[0009]

The coating material of the present invention is a polyamide having a medium molecular weight, so that it is easily dissolved in a solvent, and its viscosity is not so high even in a concentrated solution, so that it is excellent in coating workability.

After coating, the terminal carboxyl group and the terminal amino group in the polyamide easily react by heating and repolymerize, so that a film having sufficient strength can be obtained as a polymer. It is used as a covering material in a wide range of fields, such as electric wires, wires, and fused electric wires.

[0011]

Next, the present invention will be further described with reference to examples.

Example 1 A polymerization reaction of 50 molar equivalents of lauryl lactam and 1 molar equivalent of 1,10-dodecanedioic acid has a terminal carboxyl group concentration of 190 mmol / kg and a terminal amino group concentration of 5 mol / kg.
5 mmol of a polyamide having a relative viscosity of 1.4 mmol / kg of a 0.5% meta-cresol solution at 25 ° C. was polymerized with 50 molar equivalents of lauryl lactam and 1 molar equivalent of 1,6-hexamethylenediamine. Of a terminal carboxyl group of 5 mmol / kg and a terminal amino group concentration of 190 mmol / kg
% Meta-cresol solution and 5 parts by weight of a polyamide having a relative viscosity of 1.4 were added to 90 parts by weight of meta-cresol together with 0.1 part by weight of phosphoric acid, followed by stirring at 75 ° C. for 2 hours to complete dissolution. . A wire having a diameter of 1 mm was immersed in the coating material solution thus obtained, pulled up, and then dried at 350 ° C. for 1 minute. This operation was defined as one coating, and the coating was repeated five times. However, the drying time for the fifth application was 5 minutes. The wire was bent at 90 degrees along a 1 mm R-angle, and no cracking or peeling was observed in the coating film.

Comparative Example 1 A terminal carboxyl group concentration of 190 mmol / kg and a terminal amino group concentration of 5 mol equivalent obtained by polymerizing 50 mol equivalents of lauryl lactam and 1 mol equivalent of 1,10-dodecanedioic acid were obtained.
10 parts by weight of a polyamide having a relative viscosity of 1.4 mmol / kg of a 0.5% meta-cresol solution at 25 ° C. at 1.4 ° C. are added to 90 parts by weight of meta-cresol together with 0.1 part by weight of phosphoric acid. To dissolve completely for 2 hours. A wire of 1 mmφ was immersed in the coating material solution thus obtained, pulled up, and dried at 350 ° C. for 1 minute. This operation was defined as one coating, and the coating was repeated five times. However, the drying time for the fifth application was 5 minutes. This wire is 1mm
When the film was bent at 90 degrees along the corner of R, fine cracks were formed in the coating film.

Comparative Example 2 A terminal carboxyl group concentration was 80 mmol / kg and a terminal amino group concentration was 3 obtained by polymerizing 120 molar equivalents of lauryl lactam and 1 molar equivalent of 1,10-dodecanedioic acid.
10 parts by weight of a polyamide having a relative viscosity of 1.9 mmol / kg of a 0.5% meta-cresol solution at 25 ° C. are added to 90 parts by weight of meta-cresol together with 0.1 part by weight of phosphoric acid. For 16 hours, but did not completely dissolve.

Example 2 20 molar equivalents of lauryl lactam, 15 molar equivalents of caprolactam, 15 molar equivalents of 1,10-dodecanedioic acid-1,6-hexamethylenediamine salt and 1 molar equivalent of 1,10-dodecanedioic acid were polymerized. The terminal carboxyl group concentration obtained is 170 mmol / kg and the terminal amino group concentration is 10 mmol
1 / kg of 5 parts by weight of a 0.5% solution of metacresol at 25 ° C. having a relative viscosity of 1.5 at 1.5 ° C., 20 molar equivalents of lauryl lactam, 15 molar equivalents of caprolactam, 1,10-dodecane diacid-1 A terminal carboxyl group concentration obtained by polymerizing 15 molar equivalents of 1,6-hexamethylenediamine salt and 1 molar equivalent of 1,6-hexamethylenediamine is 10 mmol / kg, and a terminal amino group concentration is 17 mol / kg.
0 mmol / kg of 5% by weight of a 0.5% solution of meta-cresol at 25 ° C. and 1.5 parts by weight of a polyamide having a relative viscosity of 1.5 are added to 90 parts by weight of methanol together with 0.1 part by weight of phosphoric acid. And stirred for 1 hour to completely dissolve, thereby obtaining a coating material solution. On the other hand, a coil was prepared by winding a 1 mmφ copper wire around a pencil. The coil was immersed in the coating material solution, pulled up, and dried at 350 ° C. for 1 minute. This operation was defined as one coating, and the coating was repeated five times. However,
The drying time in the fifth application was 5 minutes. further,
While applying a load from above and below the coil, the copper wire and the copper wire were pressure-bonded via the coating film, and were fused at 200 ° C. for 10 minutes. Next, the coil was pulled up and down at a rate of 5 mm / min, and the peel strength between the copper wire and the copper wire at this time was measured. The breaking strength of the copper wire at this time was 1
Since it was 2.1 kg, the peel strength between the copper wire and the copper wire was 1
It was a large value exceeding 2.1 kg.

Comparative Example 3 20 mol equivalents of lauryl lactam, 15 mol equivalents of caprolactam, 15 mol equivalents of 1,10-dodecandioic acid-1,6-hexamethylenediamine salt and 1 mol equivalent of 1,10-dodecane diacid were polymerized. The terminal carboxyl group concentration obtained is 170 mmol / kg and the terminal amino group concentration is 10 mm
ol / kg, 10 parts by weight of a polyamide having a relative viscosity of 0.5% meta-cresol solution at 25 ° C. of 1.5 are added to 90 parts by weight of methanol together with 0.1 part by weight of phosphoric acid. The mixture was stirred for 1 hour to be completely dissolved to obtain a coating material solution. On the other hand, a coil was prepared by winding a 1 mmφ copper wire around a pencil. Immerse this coil in the coating material solution,
After pulling up, it was dried at 350 ° C. for 1 minute. This operation was defined as one coating, and the coating was repeated five times. However, the drying time in the fifth application was 5 minutes. Further, a load was applied from above and below the coil, and the copper wire and the copper wire were fused at 200 ° C. for 10 minutes in a state where the copper wire and the copper wire were press-bonded through the coating film. Next, the coil was pulled up and down at a rate of 5 mm / min, and the peel strength between the copper wire and the copper wire at this time was measured. The maximum value was 8.2 kg. .

Comparative Example 4 40 molar equivalents of lauryl lactam, 30 molar equivalents of caprolactam, 30 molar equivalents of 1,10-dodecane diacid-1,6-hexamethylenediamine salt and 1 molar equivalent of 1,10-dodecane diacid were polymerized. The terminal carboxyl group concentration was 85 mmol / kg and the terminal amino group concentration was 5 mmol
l / kg, 10 parts by weight of a polyamide having a relative viscosity of 0.5% meta-cresol solution at 25 ° C. of 1.9,
The mixture was added to 90 parts by weight of methanol together with 0.1 parts by weight of phosphoric acid and stirred at 50 ° C. for 16 hours, but was not completely dissolved.

Continuation of the front page (56) References JP-A-55-52357 (JP, A) JP-A-2-248432 (JP, A) JP-A-2-107665 (JP, A) Edited by The Chemical Society of Japan Vol. 28, Polymer Synthesis, Maruzen Co., Ltd., 1992 (pp. 260-263) Japan Society for Analytical Chemistry, Polymer Analysis Handbook, edited by Polymer Analysis Handbook, Asakura Shoten, 1985, 165 page - 169 pages Fukumoto Osamuhen, "polyamide resin Handbook", Nikkan Kogyo Shimbun, 1988, the first 63 pages - 65 pages (58) investigated the field (Int.Cl. ^7, DB name) C09D 1/00-201/10

Claims (2)

(57) [Claims] 1. A coating material solution containing, as a coating material, a polyamide having a relative viscosity of a 0.5% meta-cresol solution at 25 ° C. of 1.8 or less, comprising a terminal carboxyl group and a terminal amino group in the solution. A coating material solution for solution coating, wherein the molar ratio is adjusted to a range of 1: 4 to 4: 1 by a combination of a plurality of polyamides or addition of a diamine or dicarboxylic acid. 2. A coating method, wherein the coating material solution according to claim 1 is applied to a coating substrate, and the coating material is repolymerized by heating.