JPH0525246B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a flexible resin composition for cloth pipes that has improved flexibility, solvent resistance, bearing rust resistance, and the like. [Technical background of the invention and its problems] Conventionally, oil-based resins, oil-modified alkyd resins, and the like have been used as varnishes for cloth pipes. However, since all of these resins contain fatty acids, they have essential drawbacks: 1. Large coloration and change during heat drying 2. Large change in flexibility over time 3. Poor solvent resistance 4. Bearings High rust potential 5. May have an oily odor, etc. Up to now, various studies have been carried out to improve these drawbacks, but no satisfactory results have been obtained. [Object of the Invention] The object of the present invention was to eliminate the drawbacks of the conventional technology, and it has excellent flexibility, solvent resistance, and bearing rust resistance, and has little discoloration.
Another object of the present invention is to provide a flexible resin composition for cloth pipes that does not have an oily odor. [Summary of the Invention] As a result of extensive studies aimed at achieving the above object, the present inventor has developed an oil-free product in which a methylene long chain bond is introduced into the molecule to have an intramolecular plasticizing effect without using fatty acids. By using polyester resin, aminoaldehyde resin as a hardening agent, and caprolactone-modified epoxy resin at the same time, the disadvantages of conventional products are overcome, and the product has excellent flexibility, solvent resistance, bearing rust resistance, etc. This discovery led to the completion of the present invention. That is, the present invention provides (A) an aliphatic dibasic acid and an aliphatic glycol with 10
~40% by weight of polyester resin and (B) General formula (However, 1 to 6, n represents an integer of 1 to 9)
(C) an aminoaldehyde resin, the caprolactone-modified epoxy resin is 5 to 20% by weight based on the polyester resin, and the aminoaldehyde resin is the total resin amount [(A) + (B) +(C)], the flexible resin composition for cloth pipes is characterized by containing 5 to 25% by weight, respectively. The (A) polyester resin used in the present invention includes:
An aliphatic dibasic acid represented by the general formula HOOC(--CH ₂ ) _x -- (where x is an integer of 4 to 10) and a general formula HO(--CH ₂ ) _y -- (where y is 4 to 10) It is a polyester resin containing 10 to 40% by weight of aliphatic glycol (an integer of 10). Examples of aliphatic dibasic acids include adipic acid,
Examples include sebacic acid and dodecanniic acid, which may be used alone or in combination of two or more. In addition to aliphatic dibasic acids, acid components such as isophthalic acid, tetrahydrophthalic acid, fumaric acid, and maleic anhydride are also used. As aliphatic glycols,
1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, 1,10-
Examples include decanediol, which may be used alone or in combination of two or more. Furthermore, in addition to the aliphatic glycols mentioned above, for example, ethylene glycol,
propylene glycol, diethylene glycol,
Alcohol components such as neopene glycol, glycerin, trimethylolpropane, pentaerythritol, diglycerin, dipentaerythritol, sorbitol, etc. can be used. (A) The aliphatic dibasic acid and aliphatic glycol occupying the polyester resin are desirably in the range of 10 to 40% by weight based on the solid content of the polyester resin.
If it is less than 10% by weight, the flexibility will be significantly reduced, which is not preferable. Moreover, if it exceeds 40% by weight, the solvent resistance and film strength will decrease and it will not be suitable for practical use. The caprolactone-modified epoxy resin (B) used in the present invention is one obtained by addition-reacting ε-caprolactone to an epoxy resin. Specific compounds include Plaxel G103, Plaxel G104, and Plaxel G105 (all manufactured by Daicel, (trade name), and these may be used alone or in combination of two or more. The blending ratio of caprolactone-modified epoxy resin is 5 to 5 to the solid content of polyester resin.
A range of 20% by weight is desirable. If the amount is less than 5% by weight, the flexibility and anti-corrosion effect of the bearing will decrease, and if it exceeds 20% by weight, the drying properties will be decreased, which is not preferable. The aminoaldehyde resin (C) used in the present invention includes melamine resins, urea resins, benzoguanamine resins, etc., and these act as curing agents for the resin composition. Specifically, for example, melamine resins include Supervetsucomin J-820 (manufactured by Dainippon Ink & Chemicals Co., Ltd., trade name), Yuvan
20SE-60, Yuban 220 (manufactured by Mitsui Toatsu Chemical Co., Ltd., trade name), Vansemin 125-60 (manufactured by Harima Kasei Kogyo Co., Ltd.,
product name), etc., and these can be used singly or in combination.
Use by mixing more than one species. The blending ratio of the aminoaldehyde resin is preferably in the range of 5 to 25% by weight of the total resin solid content. If the amount is less than 5% by weight, drying properties and solvent resistance will decrease, and if it exceeds 25% by weight, the resin will become hard, both of which are undesirable. Therefore, it is limited to the above range. The flexible resin composition for cloth pipes of the present invention can be produced extremely easily by blending a polyester resin, a caprolactone-modified epoxy resin, and an aminoaldehyde resin. Usually, this resin composition is dissolved in a solvent and used as a varnish. Further, other additives may be added as necessary within a range that does not impede the effects of the present invention. The flexible resin composition for cloth pipes thus obtained is used to impregnate tubes with varnish used in electrical equipment and the like. [Examples of the Invention] Next, the present invention will be explained using Examples, but the present invention is not limited to these Examples. Examples 1-2 The polyester resin components shown in Table 1 are placed in a flask, and the temperature is gradually raised while stirring in the presence of nitrogen gas. The temperature rise rate is approximately 15°C per hour from 160°C to 230°C. If the temperature reaches 230℃,
Add a small amount of xylene and reflux the xylene while keeping it at a constant temperature of 230°C to cause an esterification reaction.
The generated condensation water is removed from the system. When the acid value became 3 or less, heating was stopped and the reaction was completed by cooling to complete a polyester resin. After adding a solvent to this polyester resin and dissolving it, predetermined amounts of caprolactone-modified epoxy resin and aminoaldehyde resin were added to prepare the varnishes of Examples 1 and 2, respectively. Comparative Examples 1-2 Polyester resins were obtained using the compositions shown in Table 1 in the same manner as in Examples. A solvent was added to this polyester resin to dissolve it, and then an aminoaldehyde resin was added to prepare the varnishes of Comparative Examples 1 and 2, respectively. In this way, using the varnishes obtained in Examples 1 and 2 and Comparative Examples 1 and 2, a 3φ polyester sleeve was treated and heat-dried for 20 minutes at 140°C four times to produce a varnish tube. Tests were conducted on bending resistance, oil resistance, heat and humidity resistance, dielectric breakdown voltage, solvent resistance, flexibility, and bearing rust resistance. The result is the second
As shown in the table, remarkable effects of the present invention were observed in all properties. Each test was conducted in the following manner. Bending resistance, oil resistance, heat and humidity resistance, and dielectric breakdown voltage are based on JIS-C-2347. Styrene resistance and xylene resistance were determined by immersing a varnish tube in styrene or xylene and determining changes in appearance. Flexibility was determined by fixing 5 cm of one end of a 20 cm varnish tube and suspending a 5 g load from the other end, and measuring the amount of deflection from the fixed part before heating and after heating at 150° C. for 24 hours.
Bearing rusting was determined by placing a bearing and varnish tube using NSK NS-7 grease in a beaker that was kept at a temperature of 70°C and relative humidity of 70%, and then placing it in a sealed beaker and placing it in a constant temperature bath at 70°C. The state of rust on the bearing surface after 2 months of installation is shown in terms of the surface rust area ratio (%).

【table】

【table】

[Table] [Effects of the invention] As is clear from the above explanation and Table 2,
The flexible resin composition for cloth pipes of the present invention does not lose its flexibility even over time and has excellent solvent resistance and bearing rust resistance. Since no fatty acids are used, there is no color change and no oily odor. Therefore, it is suitable for use in varnish tubes.

Claims (1)

[Scope of Claims] 1 (A) a polyester resin containing 10 to 40% by weight of an aliphatic dibasic acid and an aliphatic glycol; (B) a general formula (where m is an integer of 1 to 6 and n is an integer of 1 to 9); (C) an aminoaldehyde resin; 1. A flexible resin composition for cloth pipes, comprising 5 to 25% by weight of aminoaldehyde resin based on the total resin amount [(A)+(B)+(C)].