JPS6051427B2 - composite structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of a composite structure in which a cellulose acetate resin molded product is combined with another plastic molded product.

More specifically, the acetic acid cellulose resin molded product is made of acrylic resin,
In composite structures formed by combining one or more types of plastic moldings selected from polycarbonate resins and styrene resins, acrylic resins and polycarbonate resins are combined with plasticizers contained in acetic acid cellulose resins. The object of the present invention is to provide a composite structure having excellent properties by eliminating adverse effects such as whitening and glaze formation that occur in resin and styrene resin molded products. In recent years, a large number of plastics have been used, and as their uses have expanded, plastics are not only used alone, but also two or three types of plastics are being used in combination to take advantage of the characteristics of each plastic.

Acetate cellulose resin is known for its hardness, transparency, gloss, toughness,
Although plastics have excellent properties such as moldability, conventionally, when used in contact with other plastics, the plasticity contained in cellulose acetate resin can cause the plasticity of the other plastics to deteriorate. There have been many cases of glaze generation or whitening, and the use of it in contact with other plastics has been extremely limited. Acetate cellulose resin is a useful plastic material for eyeglass frames because of its hardness, gloss, moldability, and economical efficiency. On the other hand, in recent years, plastics such as polycarbonate resin and acrylic resin have been used instead of glass as materials for eyeglass lenses.

Plastic lenses have the advantage that they are less likely to break, are lighter in weight, and are easier to color than glass lenses. Therefore, eyeglasses using cellulose acetate resin as eyeglass frames and plastic lenses as lenses should be excellent eyeglasses. However, the cellulose acetate resin used for eyeglass frames contains a plasticizer during the molding process, and the plasticizer has an adverse effect on plastic lenses, causing them to whiten or form a glaze. In addition, for miscellaneous goods and toys such as buttons, combs, and head accessories, acrylic resin, casein resin, polystyrene resin, AS resin,
A wide variety of plastics, such as ABS resin, are used, and they are not only used alone, but also by combining two or three types of plastic materials, making use of the characteristics of each plastic. This helps increase the commercial value of the molded product. However, cellulose acetate resin has a negative effect on other plastics due to its plasticizer, so the gloss, transparency, and good feel of cellulose acetate resin may be affected.
Even if one wanted to take advantage of their excellent properties and use them in combination with other plastics, the reality was that they could not be used. In the future, as the amount of plastics used increases and the applications for which they are used expand, the applications for combining various plastics are expected to expand. It has been desired to invent an acetic acid cellulose resin molded product that does not cause any problems even when used as a structure.

Conventionally, as a method for solving the problem of plasticizer bleeding in cellulose acetate resin as described above, there is a method of incorporating a specific plasticizer into cellulose acetate resin.

For example, Japanese Unexamined Patent Publication No. 46-7875, No. 46-7875
Publication No. 3 discloses that trimellitic acid trialkyl ester having an alkyl group having 1 to 2 carbon atoms or alkylphthalyl alkyl glycolate having an alkyl group having 1 to 3 carbon atoms is contained in an acetic acid cellulose resin. A cellulose acetate resin composition for polycarbonate molded articles is described. Also, Japanese Unexamined Patent Publication No. 52-81366, No. 52-8916
4 and 53-58559 respectively disclose a cellulose acetate resin composition for molding styrenic resins, a cellulose acetate composite structure for acrylic resin, and a cellulose acetate composite structure for acrylic resin, each containing a diglycerin ester compound in a cellulose acetate resin. Composite structures for use are described. However, the composite structures obtained by these methods had the following drawbacks.

1. Since the desired effect is weak, the above-mentioned problems still occur in harsh environments, such as high temperature and high humidity.

2. Some plasticizers have poor hue, making it impossible to obtain cellulose acetate resin moldings with excellent hue and transparency.

3. Some plasticizers have poor water resistance, and when molded from acetic acid cellulose resin, they have poor heat resistance and moisture resistance.

4.Plasticizers are expensive.

Yet another method is to suppress the bleeding of the plasticizer by coating the surface of the plasticizer-containing plastic molded product with a specific special paint.

For example, Japanese Patent Publication No. 53-15865 describes a method for modifying the surface of a plasticized vinyl chloride resin molding by directly coating the plasticized vinyl chloride resin molding with a special polyester urethane resin. .

The present inventors attempted to suppress the bleeding of the plasticizer by coating the surface of the acetic acid cellulose resin molded product with a paint, but they were unable to obtain good results.

The present inventors have developed a composite structure by integrating a cellulose acetate resin molding containing a plasticizer with one or more types of plastic moldings selected from acrylic resin, polycarbonate resin, and styrene resin. We have conducted extensive research to eliminate the negative effects of the plasticizer contained in acetic acid cellulose resin, such as whitening and craze generation, that can be brought on acrylic resin, polycarbonate resin, and styrene resin molded products when used as a plasticizer. As a result, we have arrived at the present invention.

That is, the present invention provides an integrated product that is combined with at least one of an acrylic resin, a polycarbonate resin, and a styrene resin molded product by saponifying the surface of the acetic acid cellulose resin molded product and then coating it with a paint. This is based on the knowledge that even when used in composite structures, acrylic resins, polycarbonate resins, or styrene resins have almost no adverse effects such as whitening and craze formation.

Cellulose acetate, which is the main component of the cellulose acetate resin used in the present invention, mainly includes cellulose diacetate and cellulose triacetate, with a degree of acetylation of 50 to 57% and a degree of polymerization of 100 or more. It is preferable to use one.

Furthermore, the blending ratio of the plasticizer, which is the main component of the cellulose acetate resin used in the present invention, is 5 to 1 (by weight) per 100 parts by weight of cellulose acetate.
1) Parts by weight. Examples of such plasticizers include phthalate esters such as dimethyl phthalate, diethyl phthalate, dimethoxyethyl phthalate, and dimethoxyhexyl phthalate, phosphate esters such as triphenyl phosphate and tricresyl phosphate, and glycerin derivatives such as triacetin and triptyline. , glycolic acid derivatives such as methyl phthalyl ethyl glycolate, ethyl phthalyl ethyl glycolate, butylphthalyl butyl glycolate, sulfonic acid derivatives such as P-toluenesulfonamide, toluenesulfone-N-ethylamide, and other adipic acid derivatives,
Azelaic acid derivatives, diglycerin, polyglycerin,
Polyhydric alcohol lower fatty acid esters of pentaerythritol, dipentaerythritol, trimethylolpropane, trimethylolethane, ditriethylolethane, ditrimethylolpropane, sorbitore, mannitol and tris(2-hydroxylethyl)isocyanurate, 1,2,3 Plasticizers commonly used in acetic acid cellulose resins, such as butane tricarboxylic acid triester and bisphenol A type epoxy resin, can be used. In addition, various stabilizers are added to the cellulose acetate resin to prevent thermal deterioration and heat discoloration during thermoforming, but the cellulose acetate resin used in the present invention also contains phosphite and epoxidized resin. General commercially available stabilizers such as soybean oil, epoxy resin, hindered phenol, and thioether can be added in necessary amounts to prevent thermal deterioration and thermal discoloration. Further, as the dyes and pigments used for coloring to a desired color, known dyes and pigments for acetic acid cellulose resin may be used, and various fillers may be added depending on the purpose.

Next, the acetic acid cellulose resin molded product may be produced by any known technique, but the following method is usually used.

1. A method called the casting method.

2 A method called the wet method or block method.

3. A method called a dry method, that is, a method of obtaining a cellulose acetate resin molded product using a thermoforming machine such as an injection molding machine or an extrusion molding machine, and further processing such as cutting, cutting, bending, etc. is added as necessary.

The acrylic resin used in the present invention is preferably one produced by polymerizing a methacrylic acid ester, particularly methyl methacrylate, as a main component using heat, catalyst, light, radiation, etc., and has an average molecular weight of 800 to 30.
,00 degree is preferable.

In addition, polycarbonate resin is 4,4-dioxyalkane,
In particular, it is produced by a phosgene method or a transesterification method using bisphenol A as a main raw material, and its average molecular weight is preferably about 15,000 to 100,000. Furthermore, examples of styrene resins include polystyrene resins, impact-resistant polystyrene resins, acrylonitrile, styrene copolymer resins, acrylonitrile butadiene styrene copolymer resins, methyl methacrylate styrene copolymer resins, α-methylnetylene styrene copolymer resins, and the like.

The saponification treatment of a molded product of cellulose acetate resin may be carried out by any known technique, but a method of immersing it in a heated aqueous alkaline solution is usually suitable.

As the alkali, preferably an aqueous caustic alkali solution is used, and lower alcohols such as methanol and ethanol, as well as salts such as sodium sulfate, can be used in combination as saponification promoters. Normally, a solution with an alkali concentration of 111 (1) standard to W standard is appropriate for saponification treatment, and if the alkali concentration is low, the treatment will take a long time, and the acetic acid cellulose resin molded product will be deformed due to water absorption due to long-term immersion. arise.

If the concentration is too high, the saponification reaction will occur rapidly, resulting in a rough surface of the acetic acid cellulose resin molding, which is not suitable.
The appropriate temperature for the saponification treatment is 10°C to 70'C; at temperatures lower than 10°C, the saponification reaction proceeds easily, and at temperatures higher than 70°C, the acetic acid cellulose resin molded product may deform, so both are not suitable. .

The saponification treatment time is 3 or more, preferably 1 minute to 4 minutes.
The time range is appropriate. If the processing time is extremely short,
This is not appropriate because the surface of the acetic acid cellulose resin molded product is not uniformly saponified. It is necessary to suitably combine the alkali concentration, treatment temperature, and treatment time within the above range depending on the type and amount of the plasticizer contained in the acetic acid cellulose resin molding and the shape of the molding.

After the saponification treatment, the acetic acid cellulose resin molded product may be immersed in a dilute aqueous solution of a weak acid such as acetic acid for the purpose of removing alkaline components adhering to the surface and removing the surface. In the present invention, the paint for coating the acetic acid cellulose resin molded product is as follows:
There are oil-based paints, alcoholic paints, cellulose derivative paints, and synthetic resin paints.

More specifically, oil-based paints include drying oil paints, natural resin paints, and oil-based lacquer paints. Further, as cellulose derivative paints, there are nitrocellulose resin paints, acetyl cellulose resin paints, and acetyl butyl cellulose resin paints. In addition, synthetic resin paints include phenol resin paint, alkyd resin paint, amino resin paint, amino alkyd resin paint, vinyl acetate resin paint, acrylic resin paint, epoxy resin paint, unsaturated polyester resin paint, polyurethane resin paint, phthalate resin paint, There are melamine resin paints and paints that are chemically modified from these synthetic resin paints. Among these paints, adhesion to the surface of acetic acid cellulose resin moldings, gloss, alcohol resistance, abrasion resistance, moisture resistance, weather resistance,
One or more of them are selected in consideration of the effect on the skin, texture, curing temperature, curing time, etc., and they are used in combination or alone. These paints can contain silicon oxide, barium sulfate, calcium carbonate, titanium oxide, etc. to adjust gloss and abrasion resistance, and various dyes and pigments can also be added for coloring. A silane coupling agent may also be added to improve adhesion.

Benzophenone and salicylic acid derivatives can also be added as ultraviolet absorbers. When coating the surface of a saponified cellulose acetate resin molded product with paint, a solvent may be used to adjust the viscosity of the paint, but the compatibility with the paint, the solvent resistance of the cellulose acetate resin, and the solvent It is necessary to decide the composition by taking into account the evaporation rate, etc.

Hydrocarbons, ketones, alcohols, esters, nitrated and halogenated hydrocarbons, organic acids and water are usually used.

If this solvent composition is not appropriate, defects such as poor adhesion, whitening of the coating film, and orange skin will appear, so care must be taken.

The method of applying the paint can be freely selected from among dipping, brushing, spatula painting, and spray painting.

It is efficient to dry and cure at a high temperature within a range that does not cause thermal deformation of the material, and the performance of the coating film is also improved.

Usually, it is dried and hardened at a temperature ranging from room temperature to 100'C. Depending on the type of paint, infrared rays, ultraviolet rays, electron beams, radiation, etc. can also be used. The coating film needs to have a thickness of at least 1 micron, preferably 5 microns or more.

In the present invention, the surface of the acetic acid cellulose resin molded product is saponified and then coated with paint to prevent the plasticizer from bleeding.
This is not only because it does not adversely affect other plastics, but also because the paint improves the surface of the molded product.

The most preferred use of the composite structure of the present invention is eyeglasses,
There are miscellaneous goods and toys such as buttons, combs, headdresses, etc., but when used as eyeglasses, the lens surface is coated with melamine, for example, for lenses made of polycarbonate resin, in order to improve the abrasion resistance of the eyeglass lenses. - Lenses coated with polymers such as formaldehyde resin, polyalkylene glycol diester polymer of α,β monounsaturated carboxylic acid, and lenses made of acrylic resin, for example, a hard coating of polyorganosiloxane is formed. Although coated lenses are used, lenses with their surfaces coated can also be used as components of the composite structure described above.

Next, the present invention will be explained with reference to Examples and Comparative Examples. Examples 1 to 11 and Comparative Examples 1 to 7 Cellulose acetate (degree of acetylation 55.0%, degree of polymerization 153) 100
An extruded plate made of acetic acid cellulose resin (thickness: 8T! Rln) having a composition containing 1 part by weight of dimethyl phthalate and 45 parts by weight of diethyl phthalate as a plasticizer per part by weight was prepared.
0TWL×307077! It was cut into pieces and saponified under the conditions shown in Table 1.

Next, the coating solution shown in Table (1) was dipped in seconds, and then dried at 50° C. for 3 hours.

Acetic acid cellulose resin moldings and acrylic resin (product name: Mitsubishi Rayon Co., Ltd. AcryPets MD#001) and polycarbonate resin (product name: Teijin Kasei Co., Ltd., Panlite Ll25O) are saponified and coated as described above.
), polystyrene resin (product name: Stylon 666 manufactured by Asahi Tau Co., Ltd.), AS resin (product name: Sebian N#200 manufactured by Taicel Co., Ltd.), ABS resin (product name: Daicel (product name)
The molded product manufactured by SEVIAN Co., Ltd. (#020) was placed in close contact with the molded product and left in a constant temperature and humidity chamber at 40'C x 80% RH for one week. After that, it was taken out and cooled to room temperature, and the condition of the contact surface between the acetic acid cellulose resin molding and other plastic resins was visually observed, and the results are shown in Table 3.

As is clear from Table ■, in Comparative Example 1, in which the acetic acid cellulose resin molded product was not treated at all, the plasticizer contained in the acetic acid cellulose resin had a significant adverse effect on other plastic resin molded products. . Also, for comparison, in Comparative Examples 2 to 7, in which the surface of the cellulose acetate resin molding was treated with the paint shown in Table 1, the results were not significantly different from those in Comparative Example 1, and the surface of the cellulose acetate resin molding was treated with the paint. It is not possible to prevent the adverse effects caused by the migration of plasticizers by simply coating them with . However, in Examples 1 to 11, acetic acid cellulose resin *8
Since the surface of the molded product was saponified and further coated with paint, no adverse effects were caused by the plasticizer contained in the cellulose acetate resin.

Claims (1)

[Claims] 1. A composite structure formed by combining a cellulose acetate resin molding with one or more plastic moldings selected from acrylic resin, polycarbonate resin, and styrene resin, the surface of which is saponified and further coated with paint. A composite structure characterized by using a cellulose acetate resin molded product coated with.