CN113930140A

CN113930140A - Polyester wire enamel and preparation method thereof

Info

Publication number: CN113930140A
Application number: CN202111438584.7A
Authority: CN
Inventors: 邵飞; 曹建强
Original assignee: Dikma New Material Technology Suzhou Co ltd
Current assignee: Dikma New Material Technology Suzhou Co ltd
Priority date: 2021-11-30
Filing date: 2021-11-30
Publication date: 2022-01-14

Abstract

The invention discloses polyester wire enamel which mainly comprises the following components: 27-47 parts of polyol, 20-36 parts of terephthalic acid, 4-9 parts of curing agent, 1-5 parts of mixed leveling agent, 12-40 parts of diluent, 22-37 parts of first solvent and 0.15-0.3 part of catalyst. The mixed leveling agent comprises a BYK leveling agent, modified acrylic resin and a second solvent, wherein the mass ratio of the BYK leveling agent to the modified acrylic resin to the second solvent is (1-5) to (15-39) to (60-85); the curing agent comprises butyl orthotitanate, modified phenolic resin and blocked isocyanate, wherein the mass ratio of the butyl orthotitanate to the modified phenolic resin to the blocked isocyanate is (1.5-3) to (2-4) to (0.5-2). The polyester wire enamel has good curing rate and leveling property, so that the problem of aluminum exposure of aluminum wires is solved. The invention also discloses a preparation method of the polyester wire enamel. The preparation method of the polyester wire enamel has the advantages of simple process and convenient operation.

Description

Polyester wire enamel and preparation method thereof

Technical Field

The invention relates to the field of insulating paint, in particular to polyester wire enamel and a preparation method thereof.

Background

The enameled wire industry has more and more prominent effect in national economic development, and the price of electrolytic copper continuously rises, so that huge impact is brought to related production of copper wire raw materials and enameled wire suppliers. The aluminum enameled wire can replace a pure copper enameled wire, thereby providing huge commercial opportunities and wide markets for the development of the enameled wire industry in China, and the aluminum wire has the advantages of small specific gravity, low price, rich resources, excellent high temperature resistance, mechanical property, electrical property, chemical property and excellent freezing resistance, and is widely applied to the occasions of microwave oven transformers and reactors, demagnetizing coils, electroacoustic devices, lighting rectifiers and the like.

However, in the drawing process of the aluminum wire, due to the low hardness and the easy scratching of the surface and the residual oil stain or aluminum powder on the surface during drawing, the coated enameled wire often has bright spots and aluminum exposure on the surface, and is very easy to have turn-to-turn short circuit after being wound into a coil, thereby causing the damage of electrical equipment.

Disclosure of Invention

Based on this, it is necessary to provide a polyester wire enamel and a preparation method thereof, aiming at the problem of avoiding the aluminum exposure of the aluminum wire enamel.

The polyester wire enamel comprises the following raw materials in parts by weight:

the mixed leveling agent comprises a BYK leveling agent, modified acrylic resin and a second solvent, wherein the mass ratio of the BYK leveling agent to the modified acrylic resin to the second solvent is (1-5) to (15-39) to (60-85);

the curing agent comprises butyl orthotitanate, modified phenolic resin and blocked isocyanate, wherein the mass ratio of the butyl orthotitanate to the modified phenolic resin to the blocked isocyanate is (1.5-3) to (2-4) to (0.5-2).

In one embodiment, the mass ratio of the BYK leveling agent, the modified acrylic resin and the second solvent is (2-3): (20-35): (65-75);

the raw materials for preparing the modified acrylic resin comprise acrylic resin and a third solvent, wherein the mass ratio of the acrylic resin to the third solvent is (1-3) to (9-13).

In one embodiment, the raw materials for preparing the polyester wire enamel comprise the following components in parts by mass:

the mixed leveling agent comprises a BYK leveling agent, modified acrylic resin and a second solvent, wherein the mass ratio of the BYK leveling agent to the modified acrylic resin to the second solvent is (2-3) to (20-35) to (65-75).

In one embodiment, the polyol comprises glycerol, ethylene glycol and diethylene glycol, the mass ratio of glycerol, ethylene glycol and diethylene glycol being (10-17): (12-20): (5-10).

In one embodiment, the raw materials for preparing the modified phenolic resin comprise phenol, xylenol, formaldehyde and a fourth solvent, and the mass ratio of the phenol, the xylenol, the formaldehyde and the fourth solvent is (20-40): (20-35): (10-20).

In one embodiment, the first, second, third and fourth solvents are phenolic solvents.

In one embodiment, the diluent is selected from at least one of xylene and mineral spirits; the catalyst is zinc acetate.

The implementation of the invention has the following beneficial effects:

1. experiments prove that the leveling performance and the curing speed of the polyester enameled wire paint on an aluminum wire can be improved by reasonably compounding the raw materials, so that the problem of aluminum exposure of the aluminum wire is solved.

2. In the polyester wire enamel provided by the invention, the hydroxyl value of the polyester resin is controlled to be 0.05-0.65 mol/g, and the polyester wire enamel has good mechanical property and high curing rate.

3. The polyester wire enamel provided by the invention has stronger process margin and can be suitable for coating wires with the diameter of 0.300-0.900 mm.

4. The polyester wire enamel provided by the invention has stronger process margin and better adaptability to both felt coating lines with low solid content and mold coating lines with high solid content.

The invention also provides a preparation method of the polyester wire enamel, which comprises the following steps:

according to the mass portion, evenly mixing the polyalcohol, the terephthalic acid and the catalyst, and obtaining the polyester resin after full reaction;

uniformly mixing polyester resin, a first solvent and a diluent to obtain a resin solution; uniformly mixing the resin solution, the curing agent and the mixed leveling agent to obtain polyester wire enamel;

In one embodiment, the polyol, terephthalic acid and catalyst are mixed uniformly and fully reacted by: mixing polyalcohol, terephthalic acid and a catalyst, gradually heating to 220-230 ℃, and then vacuumizing for 100-120 s;

the operation of uniformly mixing the polyester resin, the first solvent and the diluent comprises the following steps: mixing polyester resin with a first solvent, maintaining the mixing temperature at 180-200 ℃, and maintaining the mixing time at 3-5 h; then cooling to 100-120 ℃, adding the diluent, and uniformly mixing.

In one embodiment, the preparation method of the mixed leveling agent comprises the following steps:

mixing the third solvent with acrylic resin, and stirring for 3-5 h at 70-80 ℃ to obtain modified acrylic resin; and

and mixing the modified acrylic resin, the BYK flatting agent and the second solvent, and stirring for 1-2 h at the temperature of 50-60 ℃ to obtain the mixed flatting agent.

The implementation of the invention has the following beneficial effects:

1. the process is simple and convenient to operate.

2. The polyester wire enamel obtained by the method has good leveling property and curing rate, and can solve the problem of aluminum exposure of aluminum wires.

Detailed Description

The present invention will be described in detail with reference to the following embodiments in order to make the aforementioned objects, features and advantages of the invention more comprehensible. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In the raw materials, the catalyst zinc acetate can improve the condensation rate of carboxyl and hydroxyl.

In the raw materials, polyhydric alcohol and terephthalic acid are subjected to esterification reaction under the catalysis of a catalyst to obtain the polyester resin.

Among the raw materials, the polyester wire enamel prepared by taking terephthalic acid as the raw material has good temperature resistance and scratch resistance.

Among the raw materials, the flatting agent can reduce the surface tension of the polyester wire enamel, so that the coating can form a flat and uniform coating film in the process of drying and film forming. The BYK leveling agent is produced by Bick company and takes acrylic resin as a main active substance, the adhesion of a paint film on an aluminum wire can be improved, and the leveling performance of the polyester wire enamel is further improved by the modified acrylic resin.

In the raw materials, the curing agent can promote the curing rate of the wire enamel coated on the aluminum wire by reacting with the hydroxyl on the polyester resin. The n-butyl titanate has four binding sites with hydroxyl on the polyester resin and has strong crosslinking capacity. The modified phenolic resin can improve the drying speed and the temperature resistance of the polyester wire enamel. Blocking the isocyanate may increase the rate of cure.

Experiments prove that the leveling performance and the curing rate of the polyester enameled wire paint on an aluminum wire can be improved by reasonably compounding the raw materials, so that the problem of aluminum exposure of the aluminum wire is solved.

The polyester wire enamel provided by the invention has stronger process margin, and has better adaptability from felt coating lines with low solid content to die coating lines with high solid content.

By reasonably compounding the components in the mixed leveling agent, the leveling property of the polyester wire enamel can be improved.

In one embodiment, the raw materials for preparing the polyester wire enamel comprise the following components in parts by weight:

the mixed leveling agent comprises a BYK leveling agent, modified acrylic resin and a second solvent. The mass ratio of the BYK flatting agent to the modified acrylic resin to the second solvent is (2-3) to (20-35) to (65-75).

In the raw materials, the glycerol has three hydroxyl groups capable of reacting with terephthalic acid, and the glycerol can ensure that molecular chains form a net structure. Meanwhile, glycerin is relatively viscous and plays a role in crosslinking in the reaction. Ethylene glycol and diethylene glycol can increase the flexibility of the molecular chain. Polyester resins obtained by esterification of terephthalic acid, glycerol, ethylene glycol and diethylene glycol have good flexibility and ductility.

In the above raw materials, when phenol reacts with formaldehyde, the ortho-, meta-and para-positions can react to form network cross-linking. The chain formed by reacting xylenol with formaldehyde is a straight chain, and the generated resin has better flexibility. The formaldehyde and the above-mentioned phenol raw material are dehydrated and condensed, and the obtained resin has good symmetry and heat resistance.

In one embodiment, the first, second, third and fourth solvents are phenolic solvents. Phenolic solvents include, but are not limited to, m-p-cresol, phenol, and the like.

In one embodiment, the diluent is selected from at least one of xylene and mineral spirits. The viscosity of the polyester wire enamel can be reduced by using the diluent of the above kind.

In one embodiment, the catalyst is zinc acetate. The catalyst can improve the dehydration condensation reaction rate of hydroxyl and carboxyl and promote the synthesis of polyester resin.

and S10, uniformly mixing the polyol, the terephthalic acid and the catalyst in parts by weight, and fully reacting to obtain the polyester resin.

In step S10, the reaction of glycerin, ethylene glycol, diethylene glycol, and terephthalic acid is an esterification reaction, and water is produced as a by-product during the reaction, so that the degree of progress of the reaction can be detected by detecting the temperature of steam, and when the temperature of steam is higher than 100 ℃ to 110 ℃, it indicates that all of the water has been removed. Alternatively, the degree of progress of the reaction can be judged by observing the color of the solution, and when the solution becomes transparent from milky, it is confirmed that the terephthalic acid has been completely reacted.

In the present invention, an excess amount of alcohol is used, and after the reaction is completed, the excess reactant ethylene glycol may be removed by heating or vacuum pumping.

The polyester resin prepared by the reaction has a hydroxyl value of 0.05-0.065 mol/g, and shows good adhesion, mechanical properties and curing rate.

S20, uniformly mixing the polyester resin, the first solvent and the diluent to obtain a resin solution.

In step S20, the polyester resin is dissolved in m-cresol and p-cresol at a low speed, and the mixing temperature is maintained at 180-200 ℃ for 3-5 h to ensure that the polyester resin is fully dissolved.

S30, uniformly mixing the resin solution, the curing agent and the mixed leveling agent to obtain the polyester wire enamel.

In step S30, the above components are not chemically reacted during preparation, and are physically mixed. After the polyester wire enamel is coated on the aluminum wire, the mixed leveling agent can reduce the surface tension of the polyester wire enamel, so that the polyester wire enamel is more uniformly attached to the aluminum wire.

After the curing agent is coated, the curing agent and the polyester resin are subjected to a crosslinking reaction through heating, so that the curing of the polyester wire enamel is promoted.

In one embodiment, the polyol, terephthalic acid and catalyst are mixed uniformly and fully reacted by: mixing polyalcohol, terephthalic acid and catalyst, gradually heating to 220-230 ℃, and then vacuumizing for 100-120 s.

In one embodiment, the operation of uniformly mixing the polyester resin, the first solvent and the diluent is: mixing polyester resin with a first solvent, maintaining the mixing temperature at 180-200 ℃, and maintaining the mixing time at 3-5 h; then cooling to 100-120 ℃, adding the diluent, and uniformly mixing.

and mixing the third solvent with the acrylic resin, and stirring for 3-5 h at the temperature of 70-80 ℃ to obtain the modified acrylic resin. And

In the above steps, the acrylic resin is dissolved in the third solvent, the concentration of the acrylic resin can be reduced, and the temperature is controlled to be 70-80 ℃, so that the acrylic resin can be dissolved conveniently. And then cooling to 50-60 ℃ to prevent the BYK leveling agent from being damaged.

The implementation of the invention has the following beneficial effects:

1. the process is simple and convenient to operate.

With reference to the above implementation contents, in order to make the technical solution of the present invention more specific, clear and easy to understand, the technical solution of the present invention is exemplified, but it should be noted that the contents to be protected by the present invention are not limited to the following embodiment 1 to embodiment 7.

Example 1

And (3) mixing 20g of acrylic resin with 140g of a third solvent, namely m-cresol and p-cresol, controlling the reaction temperature at 75 ℃, and stirring for 3 hours to ensure that the solution turns from white to transparent, thereby obtaining the modified acrylic resin.

2g of modified acrylic resin, 0.2g of BYK-358N (BYK leveling agent) and 7.5g of second solvent m-cresol are mixed, the reaction temperature is controlled to be 55 ℃, and the mixture is stirred for 1 hour to obtain the mixed leveling agent.

Nitrogen gas is introduced into a reaction device, 160g of glycerol, 185g of ethylene glycol, 28g of diethylene glycol, 495g of terephthalic acid and 0.15g of zinc acetate are uniformly mixed, and the temperature is gradually increased to 230 ℃. When the solution turns from milky white to transparent, vacuum pumping is carried out for 100s, and the polyester resin is obtained.

550g of m-cresol and p-cresol are added into the reaction system, the reaction temperature is controlled at 190 ℃, and the reaction time is 3 hours. The temperature was reduced to 100 ℃ and 500g of xylene was added for dilution.

Adding 34g of n-titanium butyric acid, 30g of modified phenolic resin, 13g of blocked isocyanate and 9.7g of mixed leveling agent, and uniformly mixing.

Example 2

Example 2 differs from example 1 in that 14.6g of a mixed leveling agent prepared from 7g of a modified acrylic resin, 0.1g of BYK-358N and 7.5g of a second solvent, m-p-cresol, was added.

Example 3

Example 3 differs from example 1 in that 13.6g of a mixed leveling agent prepared from 6g of a modified acrylic resin, 0.1g of BYK-358N and 7.5g of a second solvent, m-p-cresol, was added.

Example 4

Example 4 differs from example 1 in that 12.6g of a mixed leveling agent prepared from 5g of a modified acrylic resin, 0.1g of BYK-358N and 7.5g of a second solvent, m-p-cresol, was added.

Example 5

Example 5 differs from example 1 in that 11.7g of a mixed leveling agent prepared from 4g of a modified acrylic resin, 0.2g of BYK-358N and 7.5g of a second solvent, m-p-cresol, was added.

Example 6

And mixing 4.4g of modified acrylic resin, 0.1g of BYK-358N and 7.5g of a second solvent, namely m-cresol and p-cresol, controlling the reaction temperature to be 55 ℃, and stirring for 1 hour to obtain the mixed leveling agent.

Introducing nitrogen into the reaction device, uniformly mixing 170g of glycerol, 200g of ethylene glycol, 15g of diethylene glycol, 485g of terephthalic acid and 0.15g of zinc acetate, and gradually heating to 230 ℃. When the solution turns from milky white to transparent, vacuum pumping is carried out for 100s, and the polyester resin is obtained.

480g of m-cresol and p-cresol are added into the reaction system, the reaction temperature is controlled at 190 ℃, and the reaction time is 3 hours. The temperature was reduced to 100 ℃ and 320g of xylene was added for dilution.

Adding 35g of n-titanium butyric acid, 36g of modified phenolic resin, 15g of blocked isocyanate and 12g of mixed leveling agent, and uniformly mixing.

Comparative example 1

Comparative example 1 is different from example 1 in that only 7.5g of m-p-cresol, a second solvent, is added, and BYK-358N and the modified acrylic resin are not added.

Comparative example 2

Comparative example 2 is different from example 1 in that 0.2g of BYK-358N and 7.5g of a second solvent, m-p-cresol, were added alone to obtain a mixed leveling agent, and no modified acrylic resin was added.

Comparative example 3

Comparative example 3 is different from example 1 in that a mixed leveling agent obtained by adding only 2g of the modified acrylic resin and 7.5g of the second solvent, m-p-cresol, was not added, and BYK-358N was not added.

And (3) performance testing:

the polyester paints prepared in examples 1-7 and comparative examples 1-3 were coated on round aluminum wires of 0.500mm by an enameling machine, and the surface condition, softening breakdown, breakdown voltage and dielectric loss, and continuity of paint film of each sample were tested for their performance, according to the following test methods and test results:

surface condition: observing whether the surface of the cured enameled wire has the phenomena of aluminum exposure, color difference and surface unevenness;

softening breakdown test method: testing according to JB/T7599.3-2013;

the breakdown voltage test method comprises the following steps: testing according to GB 4074.13-1983;

paint film continuity test method: testing was performed according to GB 4074.20-1991;

the dielectric loss test method comprises the following steps: testing was performed according to GB 4074.5-2008.

TABLE 1 comparison of the Performance data of the polyester wire enamels of examples 1 to 7 and of comparative examples 1 to 3

As can be seen from Table 1 above, the softening breakdown temperature of examples 1-7 can reach about 320 ℃, which reaches the national standard of 130-grade polyester paint. The softening breakdown temperature of the polyester wire enamel of the invention is shown to meet the national standard.

The paint film continuity and the average breakdown voltage of examples 1-7 are significantly better than those of comparative examples 1-3; and the paint film surfaces of examples 1-7 were smoother, flatter and consistent in color. The technical effect of avoiding the aluminum exposure of the polyester wire enamel to be realized by the invention is realized.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The polyester wire enamel is characterized by comprising the following raw materials in parts by mass:

the mixed leveling agent comprises a BYK leveling agent, modified acrylic resin and a second solvent, wherein the mass ratio of the BYK leveling agent to the modified acrylic resin to the second solvent is (1-5): (15-39): (60-85);

2. The polyester wire enamel according to claim 1, wherein the mass ratio of the BYK leveling agent, the modified acrylic resin and the second solvent is (2-3): (20-35): (65-75);

3. The polyester wire enamel according to claim 1, wherein the raw materials for preparing the polyester wire enamel comprise the following components in parts by mass:

the mixed leveling agent comprises a BYK leveling agent, modified acrylic resin and a second solvent, wherein the mass ratio of the BYK leveling agent to the modified acrylic resin to the second solvent is (2-3): (20-35): (65-75).

4. The polyester wire enamel according to claim 1, wherein the polyol comprises glycerin, ethylene glycol and diethylene glycol, and the mass ratio of the glycerin, the ethylene glycol and the diethylene glycol is (10-17): (12-20): (5-10).

5. The polyester wire enamel according to claim 1, wherein raw materials for preparing the modified phenolic resin comprise phenol, xylenol, formaldehyde and a fourth solvent, and the mass ratio of the phenol, the xylenol, the formaldehyde and the fourth solvent is (20-40): (20-35): (10-20).

6. The polyester wire enamel according to claim 5, wherein the first solvent, the second solvent, the third solvent and the fourth solvent are phenolic solvents.

7. The polyester wire enamel according to claim 1, wherein the diluent is selected from at least one of xylene and mineral spirits; the catalyst is zinc acetate.

8. A method for preparing the polyester wire enamel according to any one of claims 1 to 7, which comprises the steps of:

uniformly mixing the polyester resin, a first solvent and a diluent to obtain a resin solution; and

uniformly mixing the resin solution, the curing agent and the mixed leveling agent to obtain polyester wire enamel;

9. The method for preparing polyester wire enamel according to claim 8,

uniformly mixing the polyalcohol, the terephthalic acid and the catalyst, and fully reacting: mixing the polyalcohol, the terephthalic acid and the catalyst, gradually heating to 220-230 ℃, and then vacuumizing for 100-120 s;

the operation of uniformly mixing the polyester resin, the first solvent and the diluent is as follows: mixing the polyester resin and the first solvent, maintaining the mixing temperature at 180-200 ℃, and maintaining the mixing time at 3-5 h; then cooling to 100-120 ℃, adding the diluent, and uniformly mixing.

10. The method for preparing polyester wire enamel according to claim 8, wherein the method for preparing the mixed leveling agent comprises the steps of:

mixing a third solvent with acrylic resin, and stirring for 3-5 h at 70-80 ℃ to obtain the modified acrylic resin; and