JPS63205329A - Fogging-resistant fatty acid cellulose plastic injection molding - Google Patents

Abstract

PURPOSE:To obtain the title molding which undergoes no surface delamination and can be produced in good productivity by a simple process, by applying a fatty acid cellulose solution to the surface of a fatty acid cellulose plastic injection molding, drying it and saponifying it. CONSTITUTION:A fatty acid cellulose plastic injection molding (e.g., an injection molding of a cellulose acetate plastic) is coated with a fatty acid cellulose solution and dried to form film on its surface and then subjected to saponification. In this way, a fogging-resistant fatty acid cellulose plastic injection molding free of surface delamination can be obtained simply in good productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a fatty acid cellulose plastic injection molded article having antifogging properties and subjected to saponification treatment.

(Prior art) Fatty acid cellulose plastic is a plastic that is lightweight, has excellent transparency, toughness, gloss, and moldability.It is highly safe when broken, and has a long durability after saponification treatment. Because of its antifogging properties, it is suitably used as optical components such as ski goggle lenses, underwater goggles lenses, and viewing windows.

These antifogging molded products have conventionally been produced by saponifying an extruded sheet, then punching it out and press-molding it.

(Problems to be Solved by the Invention) On the other hand, when a fatty acid cellulose plastic is molded by an injection molding method and then subjected to saponification treatment to produce an antifogging injection molded product, when the surface is wet, there is no abrasion. There was a problem that delamination occurred.

The present invention solves the above-mentioned conventional problem of delamination occurring when a fatty acid cellulose plastic injection molded product is saponified, and can be manufactured with high productivity by a simple method without depending on the shape of the molded product. The present invention provides a fatty acid cellulose plastic injection molded article having antifogging properties.

(Unfavorable Means to Solve the Problems) As a result of intensive studies to achieve the above object, the inventor of the present invention has found that, before saponifying a fatty acid cellulose plastic injection molded product, a solution of fatty acid cellulose is applied and dried.
By forming a film on the surface of the injection molded product and then applying saponification treatment, it is possible to solve the conventional problem of surface layer peeling due to abrasion in a wet state after saponification treatment. The present invention was completed based on novel findings that were previously unknown.

That is, the present invention involves applying a solution of fatty acid cellulose to the surface of a fatty acid cellulose plastic injection molded product, drying it,
This is a fatty acid cellulose plastic injection molded product having antifogging properties, which is then subjected to saponification treatment.

The fatty acid cellulose plastic injection molded products used in the present invention include cellulose acetate plastic,
Examples include injection molded products such as cellulose acetate propionate plastic and cellulose acetate butyrate plastic.

The fatty acid cellulose solution used in the present invention refers to a solution in which fatty acid cellulose plastic containing a plasticizer, stabilizer, etc., or fatty acid cellulose (raw material flakes) containing no such additives is dissolved in a solvent.

Examples of organic solvents used in this solution include ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, methanol, ethanol, isopro iR alcohol, diacetone alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, and methyl phthalyl glycol. Alcohols, ethyl acetate, isobutyl acetate,
One or more ester solvents such as isoamyl acetate and cellosolve acetate are used. When using a bath agent, it is necessary to select a solvent that can dissolve the fatty acid cellulose plastic and does not damage the appearance of the molded product base material.

The concentration of fatty acid cellulose in the solution should preferably be between 15 and 45% by weight, and the viscosity should be adjusted to a level that improves the smoothness and adhesion of the coating film, which is between 200 and 90%.
A range of 0 cps is appropriate.

Although the type of fatty acid cellulose plastic injection molded product and the type of fatty acid cellulose coated may be different, they are preferably of the same type in terms of physical properties.

For example, for cellulose acetate plastic injection molded articles, it is preferred to use a solution of cellulose acetate.

Method 9 is carried out to produce fatty acid cellulose plastic injection molded articles. After application, the coating is dried.

The drying temperature is below the heat distortion temperature of fatty acid cellulose plastic, preferably below 60°C.

Also, the film thickness after drying is 10 μm or more, preferably 3 μm or more.
A thickness of 0 μm or more is suitable, and the effect of the present invention cannot be obtained with a thickness of 10 μm or less.

Next, the saponification treatment may be carried out by a conventional method using an alkali or an acid, but a method of immersion in a heated aqueous alkaline solution is usually suitable. As the alkaline aqueous solution, a 1/8 normal to 10 normal sodium hydroxide aqueous solution and/or potassium hydroxide aqueous solution is preferably used.

If the alkali concentration is low, the processing time will be long, and the coated injection molded product will be deformed due to water absorption due to long immersion, and the surface will become white. Also, if the concentration is too high, the saponification reaction will occur rapidly, resulting in a rough surface of the film, which is not suitable.

In addition, methanol, ethanol,
Lower alcohols such as isoglono 4-nol and water-soluble plasticizers such as triacetin and triethyl phosphate can be added.

Furthermore, water-soluble inorganic salts such as sodium chloride, sodium sulfate, and sodium nitrate may be added for the purpose of homogeneous reaction, and surfactants may be added for the purpose of improving the wettability of the film surface.

The appropriate saponification temperature is 10°C to 70°C, and 1
At temperatures as low as 0°C, the progress of the saponification reaction is slow, and at temperatures as high as 70°C, the coated injection molded product may become deformed, and furthermore, the saponification reaction occurs rapidly and the coating surface becomes rough. Both things are inappropriate.

The appropriate saponification treatment time is 30 seconds or more, preferably 1 minute to 48 hours.

Depending on the type of fatty acid cellulose coated or the type and amount of plasticizer contained, it is necessary to suitably combine the alkaline strength, treatment temperature, and treatment time within the above ranges.

After the saponification treatment, the product is washed with water and dried in a conventional manner.

(Function) The present invention applies a solution of fatty acid cellulose to the surface of a fatty acid cellulose plastic injection molded product, forms a complete film with almost no physical anisotropy, and then subjects the film to saponification treatment. It is possible to obtain a fatty acid cellulose plastic injection molded product having antifogging properties that does not cause surface peeling.

(Example) Next, the present invention will be further explained using examples.

Examples 1-2 and Comparative Examples Eyeglass lenses (75 diameter) injection-molded using fatty acid cellulose plastics shown in Table 1.

After coating a bath solution of fatty acid cellulose shown in Table 2 on a 2 ml thick film by dipping method, the temperature was 52°C, the relative humidity was 7.
It was dried at 2% for 2 hours. Next, the sample was subjected to a saponification treatment according to the method shown in Table 3, thoroughly washed with water, and then dried. To examine the releasability of saponified eyeglass lenses, they were immersed in water at 25°C for 15 minutes, and then pressed with a dry rag for 6k.
It was rubbed at g/cm2. The results are shown in Table 1.

The comparative examples in Table 1 were saponified without applying a fatty acid cellulose solution, and delamination occurred due to friction with a cloth. In contrast, the product of the present invention did not cause delamination and had good antifogging properties.

Notes to Table 2 1) Cellulose acetate flakes manufactured by Daicel Chemical Industries, Ltd. (degree of acetylation 54.5% 1 degree of polymerization 178) 2) Cellulose acetate propionate plastic CP manufactured by Bayer AG
-M 3) Shin-Etsu Chemical Co., Ltd. products Table 3 (Effects of the invention) The present invention can be applied to fatty acid cellulose plastic injection molded products such as windshields, eyeglass lenses, goggles, underwater glasses, mirrors, etc., and improves productivity. This makes it possible to provide a fatty acid cellulose plastic injection molded product that has excellent properties, does not conform to the shape of the molded product, is beautiful, and has antifogging properties without surface peeling, and is of high practical value.

Claims (1)

[Claims] 1. A fatty acid cellulose plastic injection molded product having antifogging properties, which is obtained by applying a solution of fatty acid cellulose to the surface of the fatty acid cellulose plastic injection molding product, drying it, and then saponifying the product.