JPH0768390B2 - Antifogging fatty acid cellulosic plastic injection molded products - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fatty acid cellulose plastic injection-molded article having saponification treatment and having antifogging properties.

(Prior Art) Fatty acid cellulose plastic is a plastic that is light and has excellent properties of transparency, toughness, luster and molding processability, has high safety when broken, and has long-lasting anti-fogging properties due to saponification treatment. Therefore, it is suitable for use as an optical component such as a lens for ski goggles, a lens for underwater glasses, a peep window, etc.

Conventionally, these anti-fogging molded products are manufactured by saponifying an extruded sheet, punching and press-molding.

(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 anti-fog injection molded product, the surface of the plastic is wet and rubbed by rubbing. There was a problem of delamination.

INDUSTRIAL APPLICABILITY The present invention solves the above-mentioned conventional problem that delamination occurs when a fatty acid cellulose plastic injection-molded product is saponified, and can be produced with a simple method with good productivity without being restricted by the shape of the molded product. It is intended to provide a fatty acid cellulose plastic injection-molded article having antifogging property.

(Means for Solving Problems) The present inventor has conducted extensive studies in order to achieve the above-mentioned object and, as a result, before applying a saponification treatment to a fatty acid cellulose plastic injection-molded product, a solution of fatty acid cellulose was applied and dried,
Conventionally, it is possible to solve the problem of surface peeling due to rubbing in a wet state after saponification, which is a conventional problem by forming a film on the surface of the injection-molded product and then performing saponification. The present invention has been completed based on a new finding that has not been obtained.

That is, the present invention, a solution of fatty acid cellulose is applied to the surface of a fatty acid cellulose plastic injection-molded article and dried,
It is a fatty acid cellulose plastic injection-molded article having anti-fogging property, which is characterized by being subjected to saponification treatment.

The fatty acid cellulose plastic injection molded product used in the present invention includes cellulose acetate plastic,
Examples include injection molded articles 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 a fatty acid cellulose plastic containing a plasticizer, a stabilizer, or the like, or a fatty acid cellulose not containing them (raw material flakes) is dissolved in a solvent.

As the organic solvent used in this solution, for example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, alcohols such as methanol, ethanol, isopropanol, diacetone alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, methylphthalyl glycol, etc. , Ethyl acetate, isobutyl acetate,
One or more ester solvents such as isoamyl acetate and cellosolve acetate are used. In using the solvent, it is necessary to select a solvent that can dissolve the fatty acid cellulose plastic and does not impair the appearance of the molded article substrate.

The concentration of fatty acid cellulose in the solution is preferably 15 to 45% by weight, and it is necessary to adjust the viscosity so that the smoothness and adhesion of the coating film are good, and the range of 200 to 900 cps is appropriate. is there.

The type of the fatty acid cellulose plastic injection-molded product may be different from the type of the fatty acid cellulose to be applied, but the same type is preferable in terms of physical properties.

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

Application to fatty acid cellulose plastic injection molded products,
For example, it is carried out by a usual coating method such as a dipping method, brush coating, spraying method, roll coating method or flow coating method. After application, the coating film is dried. The drying temperature is not higher than the heat distortion temperature of the fatty acid cellulose plastic, and is preferably 60 ° C or lower.

The film thickness after drying is 10 μm or more, preferably 30 μm.
m or more is suitable, and if it is 10 μm or less, the effect of the present invention cannot be obtained.

Next, the saponification treatment may be carried out by an ordinary method with an alkali or an acid, but a method of immersing in a warm alkaline aqueous solution is usually suitable. As an alkaline aqueous solution, 1/8 rule-1
A 0N sodium hydroxide aqueous solution and / or a potassium hydroxide aqueous solution are preferably used.

When the alkali concentration is low, it takes a long treatment time, and the immersion treatment for a long time causes the coated injection-molded article to be deformed due to water absorption and the surface to be whitened. On the other hand, if the concentration is too high, the saponification reaction will occur rapidly, and the surface of the coating will be rough, which is not suitable.

As a saponification accelerator, methanol, ethanol,
Lower alcohols such as isopropanol and triacetin,
A water-soluble plasticizer such as triethyl phosphate can be added.

Further, for the purpose of uniform reaction, water-soluble inorganic salts such as sodium chloride, sodium sulfate and sodium nitrate, and a surfactant may be added for the purpose of improving the wettability of the film surface.

A suitable saponification temperature is 10 ° C to 70 ° C. If the temperature is lower than 10 ° C, the saponification reaction proceeds slowly, and if the temperature is higher than 70 ° C, the coating-treated injection-molded product may be deformed. It is not suitable because the surface of the film may be rough and rough.

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

It is necessary to appropriately combine the alkali strength, the treatment temperature, and the treatment time within the above range depending on the type of the coated fatty acid cellulose or the type and amount of the contained plasticizer.

After the saponification treatment, the product is washed with water and dried by a conventional method.

(Function) The present invention applies a solution of fatty acid cellulose to the surface of a fatty acid cellulose plastic injection-molded product to form a film with almost no physical anisotropy, and saponifies the film to give a saponification treatment. The present invention makes it possible to obtain a fatty acid cellulose plastic injection-molded article having anti-fogging property without surface peeling.

(Examples) Next, the present invention will be further described with reference to Examples. Example 1
2 and Comparative Example A solution of the fatty acid cellulose shown in Table 2 was applied to the spectacle lens (diameter 75 mm, thickness 2 mm) injection-molded using the fatty acid cellulose plastic shown in Table 1 by the dipping method, and then the temperature was 52 ° C. It was dried at a relative humidity of 72% for 2 hours. Then, saponification treatment was carried out by the method shown in Table 3, thoroughly washing with water and drying. In order to examine the releasability of the saponified eyeglass lens, it was immersed in water at 25 ° C for 15 minutes and then rubbed with a dry waste cloth at a pressure of 6 kg / cm ² . The results are shown in Table 1.

The comparative examples in Table 1 were saponified without coating the solution of fatty acid cellulose, and delamination was caused by rubbing with a waste cloth. On the other hand, the product of the present invention did not cause delamination and had good anti-fogging properties.

(Effect of the Invention) The present invention can be applied to fatty acid cellulose plastic injection-molded products such as windshields, spectacle lenses, goggles, underwater glasses, and mirrors, and has excellent productivity, is not restricted by the shape of the molded product, and is beautiful. It is possible to provide a fatty acid cellulose plastic injection-molded product having anti-fogging property without surface peeling, and has high practical value.

Claims (1)

[Claims] 1. A fatty acid cellulose plastic injection-molded article having anti-fogging properties, which is obtained by applying a solution of fatty acid cellulose on the surface of a fatty acid cellulose plastic injection-molded article, drying it, and then saponifying it.