JPS6136535B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing porous resin.

As a manufacturing method for porous materials, fine particles are uniformly dispersed inside the resin, and after compression molding,
There is a method of producing porous resin by extracting calcium carbonate from the resin with a mixed solution of hydrochloric acid and nitric acid. However, since this method uses calcium carbonate, the acid used is limited to hydrochloric acid, nitric acid, or a mixture of both, since calcium sulfate is produced when sulfuric acid is used. Moreover, these acids are volatile, emit smoke in the air, give off a pungent odor and are harmful, and are also extremely corrosive, which is a very serious drawback, especially when mixed.

The present invention provides a method for producing a safe resin for stamps that does not generate harmful substances except for the above-mentioned drawbacks. Sodium carbonate, potassium carbonate, magnesium carbonate, finely powdered ethylene vinyl acetate copolymer that can be injection molded without the need for sulfur.
Mix nickel carbonate or any mixture of two or more thereof, then cyclohexane,
After adding a solvent for ethylene-vinyl acetate copolymer such as benzene, acetone, and aluminum acetate and stirring uniformly, ethylene glycol, diethylene glycol, propylene glycol, etc. are added to improve the dispersibility of the added carbonate. Add a hydrophilic solvent such as and mix well with stirring, heat this mixture to 80 to 110°C to change the hardness and improve moldability, roll it to uniformly disperse the carbonate, and then shape it into a sheet. Treat with acid.
As the acid used, sulfuric acid, which cannot be used when calcium carbonate is used, can be used, and
Many other organic acids, including the related sulfamic acids, can also be used, and there is no limit to the acids used.

In particular, it is a great advantage to be able to use non-volatile acids such as sulfuric acid or sulfamic acid over volatile acids such as hydrochloric acid and nitric acid, and it also has the advantage of being able to be used with low concentration acids. . In particular, when treatment is carried out at 40 to 60°C to promote decarbonation, smoke generation due to the above-mentioned volatilization is significant when treatment is performed with hydrochloric acid, nitric acid, or a mixture thereof.
Furthermore, since these acids have a strong pungent odor and are highly corrosive, they must be carried out at low temperatures and decarbonation requires a long time. However, sulfuric acid or sulfamic acid is not volatile, and not only can high-temperature decarbonation treatment be performed, but when an ultrasonic device or the like is used to promote decarbonation treatment, it may corrode the device. The use of sulfamic acid is most advantageous for this purpose.

In addition, when using either sodium carbonate or potassium carbonate or a mixture thereof among the carbonates, not only is it extremely easy to remove the decarbonate with an acid, but it is also possible to remove the decarbonate with an acid, although it takes some time. It has the advantage that it can be extracted even if After extraction of the above decarbonate, the resin is washed with water, immersed in an organic solvent to maintain constant shrinkage and soften, and then dried, resulting in strong elasticity, less expansion deformation due to water and oil absorption, and a porous resin. A high quality resin is obtained. Further, compression molding is possible even after making the resin porous, and a porous resin having arbitrary elasticity can be obtained by controlling the acid treatment. The resin thus obtained is ideal for stamp materials, and can also be used for soundproofing materials, furnace materials, etc. The present invention will be explained below with reference to Examples.

Example 1 20 parts of ethylene-vinyl acetate copolymer (same ratio below) was thoroughly mixed with 60 parts of sodium carbonate, which was calcined as a fine powder at 500 to 650°C, and then 25 parts of cyclohexane was added thereto and stirred uniformly. After that, leave it for about 20 minutes.

Next, 20 parts of ethylene glycol was added, stirred well and left to stand for a while, and the mixture was heated to 80-110°C.
After repeating this operation for about 15 minutes on an open-type mixing roll heated to , the width of the roll is adjusted to form a sheet of desired thickness.

Next, if necessary, this is heated and molded into any shape, immersed in 20% monosulfuric acid for 24 hours, and then washed in running water for 1 hour.

Next, 30 parts of butyl alcohol, 30 parts of xylene,
A porous resin can be created by immersing it in an organic solvent of 10 parts of nitrobenzene and 5 parts of cresol for 20 minutes to keep the resin shrinkage constant. Note that the organic solvent treatment described above is secondary to the process of forming a porous structure according to the present invention.

Example 2 A resin obtained by treatment and heat molding in the same manner as in Example 1 was subjected to decarbonation treatment for 4 hours using a 13% monosulfamic acid solution and an ultrasonic cleaning device. Next, water washing was carried out five times for 5 minutes each time using an ultrasonic washing device and using fresh water each time. The resulting porous resin was the same as the resin of Example 1. Similar results were also obtained when a 20% solution of citric acid was used instead of sulfamic acid.

Example 3 A resin obtained by processing in the same manner as in Example 1 except that 60 parts of potassium carbonate was used was treated using the apparatus and method according to Example 2. The resin was the same as the resin in Example 1.

Example 4 A resin obtained by the same treatment as in Example 1 except that a mixture of 30 parts of sodium carbonate and 30 parts of magnesium carbonate was used was treated using the apparatus and method according to Example 2. The resin obtained was the same as in Example 1.

Example 5 A resin obtained by the same treatment as in Example 1 except that a mixture of 30 parts of sodium carbonate and 30 parts of nickel carbonate was used was treated using the apparatus and method according to Example 2. The resin obtained was the same as in Example 1.

Claims (1)

[Claims] 1. Ethylene-vinyl acetate copolymer that does not require vulcanization and either magnesium carbonate or nickel carbonate,
or a method for producing a porous resin, which comprises dispersing and mixing a mixture of two or more thereof, followed by compression molding, and after molding, treating with sulfuric acid, sulfamic acid, or an organic acid to extract the dispersed carbonate. .