JPS5810420B2 - The horned horn of the hunter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a resin composition for powder coating, which is composed of special ingredients and has a heat resistance higher than that of other materials. An object of the present invention is to provide a thermosetting resin composition for powder coating that is highly tough and flexible.

Conventionally, epoxy resins and polyester resins are most commonly used as thermosetting powder coating resins.

These resins are powdered, and this resin powder is used to form a resin film on the object to be coated using powder coating methods such as fluidized dipping, electrostatic powder coating, thermal spraying, and spray coating. be.

This material has excellent electrical insulation properties and mechanical properties, so it is used as insulation for various electrical equipment, but recently, as electrical equipment has become smaller and more sophisticated, it has become increasingly important to There is now a strong demand for the electrically insulating materials used to have excellent heat resistance.

Therefore, conventional epoxy resins or polyester resins cannot meet the above requirements in terms of heat resistance.

Although various studies have been made to develop resins for powder coating with excellent heat resistance, at present no product that can be put to practical use has been obtained.

Polyimide is already known as a resin with excellent high-temperature properties, but this is unsuitable as a powder coating resin for the reasons described below.

The above polyimide is produced by reacting diamine and tetracarboxylic dianhydride to obtain polyamic acid, which is then subjected to dehydration and ring closure by means such as heating, and is used as a resin for powder coating. One possible application is to separate a polyimide precursor, ie, polyamic acid, and then use the powdered product.

However, since the polyamic acid has a high melting point (800° C. or higher), it has drawbacks such as poor workability.

In view of the above-mentioned current situation, the present inventors have conducted various studies and found that an imidized glycol compound and an alcohol or (and) carboxylic acid (or its acid anhydride) having at least three functional groups. The resin composition obtained by carrying out the alcoholysis reaction and/or esterification reaction by heating has excellent heat resistance and a relatively low melting point (50 to 200°C).
The present inventors have discovered that not only can it be used in powder form, but also that it can be made into a cured product with an insoluble and infusible network structure, leading to the completion of the present invention.

That is, the present invention provides (1) general formula (A) (In the formula, R is an aliphatic or aromatic divalent group.

) and at least 3 functional groups per mol of at least one glycol compound of the imidized glycol compound represented by the general formula (B) (wherein R is the same as above) 0.05 to 0.7 mol, preferably 0.2 to 0.6 mol of polyhydric alcohols or (and) polyhydric carboxylic acids (or acid anhydrides) having
A solid resinous composition with a melting point of 50 to 200°C is obtained by adding and mixing the moles and reacting while heating and melting at 200 to 260°C, and then using a pulverizer such as a hammer mill or a ball mill. It can be easily crushed and sieved to obtain a powder with the desired particle size and long pot life.

Another manufacturing method of the present invention is that when manufacturing the resin composition for powder coating in the above (1), up to 80 mol% of the imidized glycol compounds represented by the general formulas (A) and (B) are By replacing it with (β-hydroxyethyl) telecrate, a resin composition for powder coating with even better flexibility and a longer pot life can be obtained.

When 80 mol% or more of the imidized glycol compound is replaced with bis(β-hydroxyethyl) teretocrate, the resultant powder coating resin composition does not have satisfactory heat resistance.

Incidentally, instead of bis(β-hydroxyethyl) teleclate, a product obtained by polycondensation of bis(β-hydroxyethyl) teleclate may be used.

The imidized glycol compound represented by the general formula (A) is a primary diamine having 2 moles of trimellitic acid or trimellitic anhydride and the general formula H2N-R-NH2 (wherein R is the same as above). By carrying out a heating reaction with 1 mole of ethylene glycol in excess ethylene glycol, it can be obtained in good yield without producing any side reactants.

Further, the imidized glycol compound represented by the general formula (B) is one of trimellitic acid or trimellitic anhydride.
It can be obtained in good yield by reacting 1 mole of a monoaminocarboxylic acid having the general formula H2N-R-COOH (wherein R is the same as above) in excess ethylene glycol.

Examples of polyhydric alcohols having at least three functional groups that can be used in the present invention include glycerin, tris(2-hydroxyethyl)in cyanurate, trimethylolpropane, trimethylolethane, 1,3.6-
Hexandriol, pentaerythol, etc.

In addition, examples of polycarboxylic acids (or their acid anhydrides) having at least three functional groups include trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid,
2,3,4-butanetetracarboxylic acid and their mono- and di-acid anhydrides.

The polyhydric alcohol or (and) polyhydric carboxylic acid (
If the blending amount of (or acid anhydride) is 0.05 mol or less per 1 mol of the imidized glycol compound, the number of functional groups in the resulting resinous composition will be too small, making it difficult to finally obtain a cured resin. Moreover, if the amount is 0.7 mol or more, the number of functional groups becomes too large, which tends to cause troubles such as gelation during the heating reaction, and also reduces the mechanical properties of the resulting resinous composition, making it unsuitable. It is.

In addition, in order to obtain the resinous composition according to the present invention, if necessary, a catalyst such as lead oxide, antimony trioxide, calcium acetate, tetra-iso-propyl titanate, tetrabutyl titanate, etc. may be added to the starting amount. It can be appropriately blended in a range of 0.1 to 5% by weight.

The resinous composition obtained by the production method of the present invention is pulverized using a pulverizer such as a hammer mill or a ball mill, and sieved to obtain a desired particle size. A curing accelerator such as stabilized isocyanates blocked with phenol, metal chelates such as tetra-iso-propyl titanate, tetrabutyl titanate, etc. is blended and mixed uniformly using a stirrer such as a ball mill or ribbon mixer to form a powder. It may be used as a resin composition for body coating, or it may be used as a resin composition for powder coating by adding colorants, fillers, plasticizers, etc.

The particle size of the resin composition for powder coating is preferably 350 microns or less, but a particle size of 20 microns or less is not preferred because dust tends to stand up during coating.

Since the resin composition for powder coating obtained by the present invention is thermosetting, a cured product can be obtained by curing the composition after melting it at a temperature equal to or higher than the melting point.

The curing temperature at this time varies depending on the melting point of the resin component and the type and amount of the catalyst, but is approximately 130 to 250°C.

For example, the object to be coated is heated in advance to a temperature higher than the melting point of the resin component in the resin composition for powder coating, the resin composition for powder coating is melted and coated, and then the coated object is heated afterward. Allow to harden completely.

The film thus obtained has a smooth and tough surface, and has excellent heat resistance, electrical insulation, mechanical properties, and chemical resistance.

The resin composition obtained by the present invention can be applied to various powder coating methods,
For example, various objects can be easily coated using a fluidized dipping method, an electrostatic powder coating method, a thermal spraying method, a spray coating method, or the like.

Next, the present invention will be explained by giving examples.

In addition, in giving examples, general formula (3) and (
The structural formula and abbreviation of the imidized glycol compound represented by B) are shown below.

Reference Example 1 (Manufacture of BIG-1) 19.8 g (0.1 mol) of 4,4'-diaminodiphenylmethane, 38.4 g (0.2 mol) of trimellitic anhydride, -lead oxide in a 300 ml four-way flask. 0.0
Add 4 g and 150 g of ethylene glycol, stir while blowing nitrogen, and dissolve at a temperature from room temperature to 150°C. After stirring at 150 to 180°C for 1 hour, a yellow precipitate due to imidization will precipitate. .

During this time, water produced by the reaction is distilled out of the system.

Then, by stirring for 3 hours at the reflux temperature of ethylene glycol, the precipitate is dissolved by esterification to form a homogeneous solution.

After continuing to reflux for about 1 to 2 hours, the mixture was cooled.

Upon cooling, pale yellow crystals begin to precipitate.

The precipitated crystals were separated in a furnace, thoroughly washed with acetone, and then vacuum dried to obtain BIG-1 with a yield of 96%.

The melting point of this product was 254°C to 255°C.

Elemental analysis value Actual value as C35H26N2O10
C, 66, 12%; H, 4, 26%; N, 4.31% Theoretical value C, 66, 24%; H, 4, 13%; N, 4.4
1% Reference Example 2 (Manufacture of BIG-2) 4.4'-diaminodiphenyl ether 20g (0,1
mol), trimellitic anhydride 38.4g (0.2 mol)
, 0.1 g of tetra-iso-propyl titanate and 130 g of ethylene glycol were placed in a 300 ml Yotsuro flask, and B was prepared in a yield of 98% in the same manner as in Reference Example 1.
IG-2 was obtained.

The melting point of this product was 216-218°C.

Elemental analysis value Actual value as C34H24N2O11 C
, 64,03%; H, 3,88%; N, 4.32% theoretical value C, 64,15%; H, 3,80%; N, 4.40
% Reference Example 3 (Manufacture of EIG-1) P-aminobenzoic acid 13.
7 g (0.1 mol) trimellitic anhydride 19.2 g (0
, 1 mol), - Add 0.03 g of lead oxide and 70 g of ethylene glycol, stir while blowing nitrogen gas, and dissolve at a temperature from room temperature to 150°C, then increase the temperature to the reflux temperature of ethylene glycol. After stirring for about 3 hours, it was cooled.

The precipitated crystals were filtered, thoroughly washed with distilled water and methanol, and vacuum dried to obtain EIG-
I got 1.

The melting point of this product was 184-185°C.

Elemental analysis value Actual value as C20H17NO8 C, 60, 22%; H, 4, 33%; N, 3.
56% theoretical value C, 60, 15%; H, 4, 29%; N
, 3.51% Reference Example 4 (Production of EIG-2) m-aminobenzoic acid 13.7 g (0.1 mol), trimellitic anhydride 19.2 g (0.1 mol), -lead oxide 0.
03g and 80g of ethylene glycol were charged into a 30M four-way flask, and EIG-2 was obtained in a yield of 95% by the same operation as in Reference Example 3.

The melting point of this product was 141°C.

Elemental analysis value Actual value as C2OH17NO8 C, 59,93%; H, 4,12%; N, 3.
37% theoretical value C, 60, 15%; H, 4, 29%; N
, 3.51% Comparative Example 1 2% by weight of silica powder (Aerosil #30
0, Nippon Aerosil ■ (trade name) was added, ground in a ball mill, and sieved to obtain a powder composition of 100 μm or less.

Using this composition, a coating film was formed on a chromium-plated iron plate with a thickness of 0.3 mm by electrostatic powder coating.

This was heated at 200° C. for 1 hour to cure the coating film.

The thickness of the coating film formed was 70μ.

The results of the film peeled off from the iron plate using a thermobalance (in air, heating rate 10°/min) were as follows.

10% weight loss Temperature change: 280°C Weight loss rate at 500°C: 90-100% Further, the tensile strength of this film at room temperature after aging at 250°C for 500 hours was 1 kg/mm2 or less.

Comparative Example 2 2% by weight of Aerosil #300 was added to polyester resin powder (VAN-16, trade name of Hoechst), ground in a ball mill, and sieved to obtain a powder composition of 100 μm or less.

Using this composition, a coating film was formed on a chromium-plated iron plate with a thickness of 0.3 mm by electrostatic powder coating.

This was heated at 200°C for 1 hour to cure the coating film.

The thickness of the coating film formed was 70μ.

The results of the film peeled off from the iron plate using a thermobalance (in air, heating rate 10°/min) were as follows.

10% weight loss Temperature change: 310°C Weight loss rate at 500°C: 90-100% Further, the tensile strength of this film at room temperature after aging at 250°C for 500 hours was 1 kg/mm2 or less.

Example 1 1 mol of the imidized glycol (BIG-1) and 0.4 mol of glycerin were mixed while stirring while blowing nitrogen gas, stirred at 250°C for about 30 minutes, and then rapidly cooled to reduce the melting point. A resinous composition was obtained at 130°C (hot plate method).

Example 2 1 mol of the imidized glycol (BIG-2) and 0.4 mol of trimellitic anhydride were mixed under nitrogen gas blowing, stirred at 250°C for about 10 minutes, and then rapidly cooled. A resinous composition with a melting point of about 120°C was obtained.

Example 3 1 mol of the above imidoglycol (BIG-1), Tris (
0.2 mol of 2-hydroxyethyl) isocyanurate,
0.2 mol of trimellitic anhydride was mixed while blowing nitrogen gas, stirred at 250°C for about 10 minutes, and then rapidly cooled to obtain a resinous composition with a melting point of about 140°C.

Example 4 1 mole of the above imidoglycol (BIG-2), 0.6 mole of glycerin, and 1 mole of bis(β-hydroxyethyl) terephthalate were mixed while blowing nitrogen gas, and 250
After stirring at ℃ for about 20 minutes, the melting point was 1.
A resinous composition at 00°C was obtained.

Example 5 Nitrogen gas was blown into 1 mol of the imidoglycol (BIG-1), 1 mol of glycerin, 0.5 mol of trimellitic acid, 2 mol of bis(β-hydroxyethyl) terephthalate, and 1-1 g of tetraisopropyl titanium. After stirring at 250°C for about 10 minutes, the mixture was rapidly cooled to obtain a resinous composition with a melting point of 70°C.

Example 6 1 mol of the imidoglycol (EIG-1), 1 mol of glycerin, 0.5 mol of trimellitic anhydride, bis(β
2 moles of -hydroxyethyl) terephthalate and 2 g of tetraisopropyl titanate were mixed while blowing nitrogen gas, stirred at 250°C for about 15 minutes, and then rapidly cooled to obtain a resinous composition with a melting point of 50°C.

Example 7 1 mole of the imidized glycol (EIG-2), 0.1 mole of glycerin, 0.1 mole of pyromellitic acid, and 1 g of lead monoxide were mixed while blowing nitrogen gas, and stirred at 250°C for about 5 minutes. After that, it is rapidly cooled to a melting point of 110℃.
A resinous composition was obtained.

The resinous compositions obtained in Examples 1 to 7 were coarsely pulverized in a ball mill, two cycles of Aerosil+300 were added, pulverized again in the ball mill, and then sieved to obtain a powder composition of 100 μm or less.

A coating film was formed using the powder composition on a chromium-plated iron plate with a thickness of 0.3 mm by electrostatic powder coating method, and this was heated at 250°C for 24 hours to form a cured resin coating film with a thickness of 70 μm. I got it.

The properties of the film obtained by peeling from the iron plate are as shown in the table.

As is clear from the above results, the resin composition for powder coating obtained by the production method of the present invention has a relatively low melting point and can be put to practical use. It is smooth and strong, and has particularly good heat resistance, so it is suitable for electrical insulation materials such as electrical equipment.

Claims (1)

[Scope of Claims] 1 An imidized glycol compound represented by the general formula (A) (wherein R is an aliphatic or aromatic divalent group), and a general formula (B) (in the formula , R is the same as above) polyhydric alcohols or (and) polyhydric carboxylic acids (or their acid anhydrides) having at least 3 functional groups per mole of at least one glycol compound of the imidized glycol compound represented by 1. A method for producing a resin composition for powder coating, which comprises heating 0.05 to 0.7 mol of the resin composition and pulverizing the obtained resin composition. 2. The general formula (A) and (
A part of the imidized glycol compound shown in B) was converted into bis(
1. A method for producing a resin composition for powder coating, which comprises pulverizing a resin composition obtained by heating the resin composition in place of β-hydroxyethyl) terephthalate.