KR0140484B1 - Method of alkylation of fibric plastic mould - Google Patents

Abstract

The present invention relates to a process for alkalizing a fiber- crab plastic molding, wherein a process for alkalizing a fiber-based plastic molding using an alkaline alcohol solution is carried out using an acidic aqueous solution immediately after the alkalizing treatment. It is supposed to be.

Description

[Name of invention]

Alkaline treatment of fibrous plastic molding

Detailed description of the invention

[Technical Field]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for alkalizing a fibrous plastic molding, and more particularly, to an alkalizing treatment method for an antifogging fibrous plastic molding having excellent smoothness, which is used in water glasses, ski goggles, mirrors, various shading protectors, and the like. .

[Background of invention]

Fibre-based plastic moldings have excellent transparency, toughness at low temperatures, gloss, weather resistance, and processing characteristics, and are used in water glasses, goggles, and the like, which require good antifogging properties by alkalizing the surface.

Background Art Conventionally, a method of using an alkali hydroxide (NaOH) or potassium hydroxide (KOH) is known as a method of alkalizing the surface of a fibrous plastic molded product to prevent fogging. However, in the conventional method of alkalizing treatment of fibrous plastic molding, the smoothness and gloss are damaged depending on the processing conditions, the appearance of spots, the appearance of stardust (a slight blur due to innumerable points), and the occurrence of optical distortion. There is a problem that a decrease in mechanical strength occurs.

[Purpose of invention]

The present invention has been made in order to solve the problem of the alkali treatment method of the conventional fiber-based plastic molding, the damage of gloss and smoothness, the appearance of stains, the generation of stardust, the decrease in mechanical strength and optical distortion does not occur. It is an object of the present invention to provide a method for alkalizing a fibrous plastic molding.

[Summary of invention]

In the alkali treatment method of the fibrous plastic molding of the present invention, the neutralization reaction is performed at a rapid rate using an acidic aqueous solution after a predetermined alkalizing treatment time elapses in which the alkalizing treatment is performed in a swollen state using an aqueous alkaline alcohol solution of the fibrous plastic molding. It is characterized in that the swelling surface is made dense and changed into a layer so as to be a molded article having excellent gloss and smoothness and excellent antifogging performance.

[Description of Specific Embodiment of the Invention]

Hereinafter, embodiments of the present invention will be described in detail.

As the cellulose-based plastic molding used in the present invention, moldings such as cellulose acetate plastic, cellulose triacetate plastic, cellulose acetate propionate plastic, cellulose acetate butylate plastic, and the like, may include cellulose-based plastic moldings.

In order to alkalinize the fibrous plastic molding using the alkaline alcohol demand solution, the molding must be brought into contact with the alkaline alcohol aqueous solution for a certain time. For example, the molded product is immersed in an alkaline aqueous alcohol solution, or an alkaline alcohol aqueous solution is sprayed or applied to the surface of the molded product. When the molded article and the alkaline alcohol aqueous solution are in contact with each other, the range of 10 ° C. to 60 ° C. is preferable. If the temperature is lower than 10 ° C., the alkalinization rate of the molding surface is slow. If the temperature is higher than 60 ° C., the molding may be a sheet. It may deform | transform, and also alcohol evaporates severely and the surface which is neither smooth nor uniform is obtained.

In addition, the contact time between the molding and the alkaline alcohol aqueous solution is suitable for 7 seconds to 30 minutes, preferably 7 seconds to 15 minutes. In 7 seconds or less, the surface of the molded article does not swell sufficiently and the alkalization reaction does not proceed sufficiently. In addition, if a high concentration of alkaline alcoholic solution is used for 30 minutes or more, the gloss and smoothness of the surface may be impaired.

The alkaline alcohol aqueous solution used in the present invention is a mixture of an alkaline aqueous solution and a lower alkyl alcohol, and the lower alkyl alcohol has a function of promoting swelling of a molded product, and methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol and the like are preferable. Do.

The mixing ratio of the lower alkyl alcohol in the alkaline alcohol aqueous solution is 10 to 50% by volume is good, less than 10% by volume, the swelling and alkalizing rate is slow and economically not practical. In addition, if it exceeds 50% by volume, solvent cracking or whitening is liable to occur, and the alkali used in the alkaline alcohol solution is preferably sodium hydroxide or potassium hydroxide, and the concentration of alkali is suitably in the range of 1 to 10. .

If the alkali concentration is low, the alkali treatment takes a long time. If the molding is deformed by prolonged immersion and the alkali concentration is high, the alkali reaction may occur rapidly, and the surface may be whitened and cracks may be undesirable. In addition, in order to advance the alkalizing process smoothly, a surfactant may be added to the alkaline alcohol aqueous solution. The amount of addition to the alkaline alcoholic solution is suitably 1 to 10% by weight.

In the present invention, the molded product is alkalized with an alkaline aqueous alcohol solution, and then neutralized with an acidic aqueous solution without performing other treatment such as washing immediately. The neutralization treatment may be performed for 5 seconds to 5 minutes at room temperature (20 to 30 ° C.) in a 1 to 10 N aqueous solution of inorganic acids such as sulfuric acid, hydrochloric acid, acetic acid, phosphoric acid, organic acids such as hydroxyl, aliphatic and aromatic sulfonic acid.

The acid may be sulfuric acid or hydrochloric acid, and depending on the shape of the molded product, neutralization treatment with an acidic aqueous solution may be performed by adding an acidic aqueous solution of an amount necessary to neutralize it to the alkaline alcohol aqueous solution. This alkaline treatment method is particularly effective for treating one side of molded products such as fibres, plastic water glasses, etc., and a predetermined amount of alkaline alcohol aqueous solution is injected into one side of molded products such as water glasses by using a divider. What is necessary is just to add the acidic aqueous solution of the quantity required for neutralization of the alkaline alcoholic aqueous solution which used after alkalizing to the alkaline alcoholic aqueous solution. In this way, since the neutralization reaction is completed, there is no need for a treatment tank or the like, the treatment can be performed on a line, and since the washing water is a minimum amount, it is an economically excellent treatment method.

Hereinafter, the present invention will be described in more detail with reference to Examples.

[Examples 1 to 14]

Alkaline aqueous solution of alkali concentration shown in Table 1 using a dispenser (approximately 0.01 ml) in a 45 mm x 30 mm x 1.5 mm lens section made of injection molded cellulose acetate propionate and a 3 mm deep water goggle. Is injected into the inner surface of a 2.5 ml lens and treated under alkaline conditions shown in Table 1.

The acidic aqueous solution (20 wt% aqueous hydrochloric acid solution) required for the neutralization reaction was immediately collected using a dispenser and added to the aqueous alkaline alcohol solution to carry out the neutralization reaction. After completion of the neutralization reaction, the temperature of the solution was increased to 20 ° C by the heat of neutralization. After the neutralizing solution was dumped, water washing was performed, and a molded article obtained by drying at a temperature of 50 ° C. for 30 minutes using a hot air dryer was tested. Table 2 shows the test conditions and Table 3 shows the test results.

[Comparative Examples 1 to 14]

Except for omitting the neutralization step, washing is performed immediately after the alkalizing treatment under the same conditions as in Examples 1 to 14. The molded article obtained by drying in the same way was tested.

Test conditions are shown in Table 2 and test results in Table 4.

Example 15

In Example 4, the same alkaline treatment and neutralization treatment as in Example 4 were conducted except that cellulose acetate butyl rattle was used in place of cellulose acetate propionate. Same as in Example 4, excellent results were obtained.

Example 16

In Example 4, the same alkaline treatment and neutralization treatment as in Example 4 were performed except that cellulose acetate was used in place of cellulose acetate propionate. In Example 4, the same alkaline treatment and neutralization treatment as in Example 4 were conducted except that cellulose triacetate was used instead of cellulose acetate propionate. Excellent results as in Example 4 were obtained.

Example 17

In Example 4, the same alkaline treatment and neutralization treatment as in Example 4 were performed except that cellulose triacetate was used in place of cellulose acetate propionate. Excellent results as in Example 4 were obtained.

Example 18

A 100 mm × 100 mm × 0.8 mm plate of cellulose acetate propionate was alkalized in a solution of 5 N potassium hydroxide containing 10% by weight of surfactant (10% by volume of methyl alcohol) at 40 ° C. for 7 minutes, Thereafter, the mixture was immersed in 20% aqueous hydrochloric acid solution at room temperature for 3 minutes without washing with water, and neutralized.

Next, the plate obtained by washing with water and drying at a temperature of 50 ° C. for 30 minutes using a hot air dryer was subjected to the same test as in Example 1. The same result as in Example 1 was obtained.

Comparative Example 15

In Example 18, operation similar to Example 18 was performed except having washed with water after the alkalization treatment, and neutralized. Some minor scratches occurred in the friction test.

[Effects of the Invention]

As described above, in the present invention, since the neutralization treatment is performed by the acidic aqueous solution immediately after the alkalizing treatment, it is possible to produce a fibrous plastic molded article having excellent antifogging and friction resistance. Further, the treatment does not impair the gloss and smoothness of the surface of the molded article, the occurrence of spot shapes, the generation of star dust, the generation of optical distortion, and the decrease in mechanical strength. Therefore, it is an excellent fiber-based plastic molding that can prevent the anti-fog has the effect that can be widely used in applications requiring a low cost and anti-fog performance.

Claims (3)

A method for alkalizing a cellulose-based plastic molding, wherein the cellulose-based plastic molding is subjected to a neutralization reaction immediately after alkalizing with an alkaline alcoholic solution. The alkali treatment method according to claim 1, wherein the alkaline compounds used in the aqueous alkaline alcohol solution are sodium hydroxide and potassium hydroxide. The method of claim 1, wherein the alcohol used as the alkaline alcohol aqueous solution is lower alkyl alcohol, the lower alkyl alcohol is at least one selected from methyl alcohol, ethyl alcohol, isopropyl alcohol and n-propyl alcohol fibrin system Alkaline treatment of plastic moldings.