JPH0674338B2 - Surface decoration method for polyolefin resin molded products - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decorating the surface of a polyolefin resin molded product, more specifically, a surface material such as fiber, cloth, non-woven fabric, leather or foil is transplanted on the surface of the polyolefin resin molded product. Alternatively, the present invention relates to a method of attaching and decorating the surface of a molded product with high adhesive strength.

[0002]

2. Description of the Related Art In recent years, due to the development of synthetic resin technology, synthetic resins have been used in various fields such as automobile parts, home electric appliances and electronic devices. To increase the added value of these products, the surface of resin molded products is flocked, cloth, non-woven fabric,
Surface decoration such as attaching leather or foil is performed. Currently, ABS resins, polyolefin resins, etc. are used as typical resins for which surface decoration is performed. Adhesion between the resin and the adhesive is required as one of the important characteristics required when decorating the surface of the molded product. However, since the ABS resin has a polar group in the resin structure, the adhesion with the adhesive is relatively good, while the polyolefin resin has no polar group and the surface is extremely inactive. Therefore, the adhesiveness with the adhesive is poor. Therefore, before applying the adhesive to the surface of the molded product, a primer containing chlorinated polypropylene or the like is applied to enhance the adhesive force. Further, as other methods for improving the adhesion between the polyolefin resin molded product and the adhesive, various methods such as a chemical oxidation method, a radiation graft polymerization method, a plasma treatment method, and an ultraviolet pre-irradiation method have been proposed. For example, in the chemical oxidation method, a waste liquid treatment of the used chemical is burdened, and in the radiation graft polymerization method, the processing speed is slow and the process is complicated, which is economically problematic. The plasma processing method has a problem in that stable quality is difficult to obtain, it takes time, and the equipment is expensive. The conventional ultraviolet pre-irradiation method uses ultraviolet rays having a wavelength of 300 nm or more as a main wavelength, the irradiation takes time, and the effect of adhesion is insufficient. In addition, as an adhesive, a water-dispersed adhesive is required rather than a solvent-based adhesive due to safety and hygiene problems. Polyolefin resin has a large contact angle with water, and the adhesiveness with a water-dispersed adhesive is inferior to that of a solvent-based adhesive, and the above method does not sufficiently improve the adhesiveness. When the material is flocked or attached, the adhesive strength is weak and it cannot be put to practical use. As mentioned above, ABS resin is
Although the adhesion with the adhesive is relatively good, the ABS resin itself is expensive, while the polyolefin resin is inexpensive, but the primer coating is required, which increases the cost in the production process. I have a problem.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to improve the adhesion between a molded article and an adhesive, and to implant a fiber or a skin material on the surface of the molded article. Alternatively, it is to provide a surface decoration method for strengthening the adhesive force when applied.

[0004]

According to the present invention, the surface of a polyolefin resin molded article is preheated at a temperature of 45 ° C. or higher and lower than its melting point, and after contacting with an organic solvent near room temperature, the irradiation wavelength It is a surface decoration method for a polyolefin resin molded article, which comprises irradiating with ultraviolet rays having a main wavelength of 185 nm and attaching a flock or a skin material through a water-dispersible adhesive.

The polyolefin resin referred to in the present invention is
It includes the following: (A): Low, medium, high density polyethylene, polypropylene,
Α-Olefin homopolymer such as poly 1-butene and poly 4-methyl-1-pentene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer , Α-1-olefin copolymers such as ethylene-1-hexene copolymer, propylene-1-butene copolymer, ethylene-propylene-1-butene copolymer and mixtures thereof. (B): Component (A) and rubbers such as natural rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, butyl rubber, chloroprene rubber, butadiene rubber,
Mixtures of isoprene rubber, fluorine rubber, ethylene-propylene rubber, urethane rubber, acrylic rubber, etc. (C): ethylene- (meth) acrylic acid copolymer, ethylene- (meth) in the composition of the component (A) or the component (A) and the component (B)
Acrylic ester copolymer, a composition in which a copolymer of ethylene and an unsaturated carboxylic acid or a derivative thereof such as an ionomer resin is blended, or the component (A) and (B)
A resin or composition in which a component is modified with a monobasic acid such as methacrylic acid or acrylic acid, a dibasic acid such as maleic acid, maleic anhydride, or itaconic acid. (D): Inorganic filler or organic filler in the above components (A), (B) and (C), for example, calcium oxide, magnesium oxide, calcium hydroxide, magnesium hydroxide,
Inorganic fillers such as aluminum hydroxide, magnesium carbonate, calcium silicate, magnesium silicate, calcium sulfate, calcium carbonate, barium sulfate, calcium sulfite, talc, clay, glass, basic magnesium carbonate, dolomite, and vilsonite and / or wood flour , Mixtures with organic fillers such as cellulose fibers, synthetic fibers and melamine powder. Among the above resins or compositions, polypropylene-based or polyethylene-based resins are most preferable in terms of mechanical strength and cost. The polyolefin-based resin molded article of the present invention, using the above resin or composition, extrusion molding, injection molding,
Sheet, by rotational molding, compression molding, blow molding, etc.
It is molded into plates, tubes, containers, dolls, and odd-shaped products.

In the present invention, the light with which the polyolefin resin molded article is irradiated is ultraviolet light having a main working wavelength near 185 nm, where the energy of light having a short wavelength accounts for 85% or more of the total energy. The material of the ultraviolet irradiation lamp is preferably one having a high transmittance of ultraviolet rays having a short wavelength, and synthetic quartz glass having a higher purity than natural quartz glass is preferable. In the present invention, the surface of the polyolefin resin can be more activated by using such short wavelength ultraviolet rays. According to the present invention, even for a highly crystalline polyolefin resin such as high-density polyethylene or polypropylene, the molded product is heated in advance, and the short-wavelength ultraviolet ray (185 nm is applied after contact with an organic solvent). By irradiating the main wavelength), the adhesive strength after surface decoration can be significantly improved.

As the organic solvent used in the present invention, the solubility parameter (SP
Value), and those having an ultraviolet absorbing property are preferred, for example, benzene, toluene, xylene, decalin, aromatic hydrocarbon solvents such as tetralin, carbon tetrachloride, trichloroethylene, tetrachloroethylene, chloroform, Halogenated hydrocarbon solvents such as trichloroethane, tetrachloroethane, trichlorotrifluoroethane, brombenzene, chlorobenzene and dichlorobenzene are used. Of these, a mixture of benzene or tetrachloroethylene and carbon tetrachloride is particularly preferable. The above mixing ratio is tetrachloroethylene 10-98.
The range of vol% and carbon tetrachloride 2 to 90 vol% is more preferable, and the range of tetrachloroethylene 50 to 98 vol% and carbon tetrachloride 2 to 50 vol% is preferable. Benzene is opened by ultraviolet irradiation in an oxygen atmosphere to form a long-chain conjugated double bond type dialdehyde. This aldehyde is bonded to the chain of the polyolefin resin, and the conjugated double bond part absorbs ultraviolet rays to accelerate the photooxidation reaction, thereby activating the surface,
It is considered that the adhesive strength is improved. In the case of a halogenated hydrocarbon solvent, chlorine radicals are generated by ultraviolet irradiation, which binds to the polyolefin chain, also abstracts hydrogen radicals from the polyolefin chain, and oxygen atoms bond to the radical atoms generated on the polyolefin chain. ,
It is considered that oxygen-containing groups are generated. It is considered that such oxygen-containing groups activate the surface and improve the adhesive strength.

The method of contacting the polyolefin resin molded product with the above solvent is not particularly limited, and a usual method such as a wiping method or a immersing method may be used. The contact time varies depending on the type of resin and the type of solvent and is appropriately selected. In the present invention, it is important to heat only the molded product without heating the solvent. This heating temperature is in the range of 45 ° C. or higher and its melting point or lower. This heating temperature is 45
If the temperature is lower than ℃, the adhesive strength will not be improved, and if it is higher than the melting point, the molded product will be deformed, which is not preferable. When the molded product is preheated and brought into contact with the organic solvent, since the molded product has already been heated, a short contact treatment provides a high modifying effect of the organic solvent on the surface of the molded product.
The evaporation amount of the organic solvent can also be suppressed to a low level. further,
Since only the molded product is heated, there are advantages in that it requires less heat energy and that the heating device can be small.

The water-dispersible adhesive referred to in the present invention includes synthetic rubber latex, resin emulsion and water-soluble resin.
One kind or two or more kinds are used, and specifically, synthetic rubber latex such as chloroprene, SBR, NBR, MBR, natural rubber, polyvinyl acetate, polyvinylidene chloride, polyvinyl chloride, polyacrylate, polyurethane, etc. Examples thereof include water-soluble resins such as homo- or copolymer synthetic resin emulsions, water-soluble acrylic resins, water-soluble polyester resins, and water-soluble polyurethane resins.

The surface decoration referred to in the present invention is specifically,
The above-mentioned adhesive is used to perform flocking on the surface of the molded product, or to apply a surface material such as cloth, non-woven fabric, leather or foil. The flocking method may be any of a mechanical type, a hand-planting type, and an electrostatic type, but the electrostatic type is preferable. Pile used for flocking is natural fiber such as rayon, cotton, wool, vinyl chloride fiber, acrylonitrile copolymer fiber, polyacrylic fiber, urethane fiber, polyester fiber,
Synthetic fibers such as nylon fibers, leather, pulp,
Fibrous fine powder such as urethane synthetic leather can be used. Also,
The thickness and length of the pile are similar to those used for normal electrostatic flocking, but the thickness is 0.5 to 30 denier and the length is 0.2 to 10 mm.
Is effective, but mechanical flocking and hand flocking are not limited to this.As cloth, leather and foil to be applied to the surface of the molded body,
Natural fibers such as wool, hemp and cotton, recycled artificial fibers such as rayon and protein fibers, polyurethane-based, polyvinyl chloride-based,
Polyvinyl alcohol-based, polyvinylidene chloride-based, polyamide-based, acrylonitrile polymer and copolymer synthetic fibers and their mixed-spun fabrics, woven fabrics, knitted fabrics, non-woven fabrics such as rayon, nylon, polyester, etc. Examples of the metal foil include iron, zinc, and the like.

In the present invention, an antioxidant or a heat stabilizer (a hindered phenol type, a phosphite type, a hydroquinone type, a thioether type, etc.), an ultraviolet ray, or an ultraviolet ray is added to the above resin or composition as long as the object of the present invention is not impaired. Absorbents (benzotriazole-based, resorcinol-based, salicylate-based, etc.), dyes or pigments, flame retardants, antistatic agents, nucleating agents (crystallization accelerators), lubricants or release agents can be added. Several kinds of the above additives may be combined.

[0012]

EXAMPLES The present invention will be specifically described with reference to the following examples. The polyolefin resin used in this example is as follows. (Sample number) A-1: Propylene-ethylene block copolymer MFR = 8.0 g / 10min (JIS K 6758) Density = 0.90 to 0.91 g / cm ³ (JIS K 6758) (Nippon Petrochemical Co., Ltd.) A- 2: Propylene-ethylene random copolymer MFR = 7.0 g / 10min (JIS K 6758) Density = 0.90-0.91 g / cm ³ (JIS K 6758) (Nippon Petrochemical Co., Ltd.) A-3: Propylene homopolymer MFR = 8.0 g / 10min (JIS K 6758) Density = 0.90-0.91 g / cm ³ (JIS K 6758) (Nippon Petrochemical Co., Ltd.) B-1: Low density polyethylene MFR = 5.0 g / 10min (JIS K 6760) ) Density = 0.921 g / cm ³ (JIS K 6760) (Nippon Petrochemical Co., Ltd.) B-2: High density polyethylene MFR = 5.3 g / 10min (JIS K 6760) Density = 0.963 g / cm ³ (JIS K 6760) ) (Nippon Petrochemical Co., Ltd.) B-3: Linear low-density polyethylene MFR = 8.0 g / 10min (JIS K 6760) Density = 0.923 g / cm ³ (JIS K 6760) (Nippon Petrochemical Co., Ltd.) C-1: Propylene polymer / Propylene-ethylene rubber mixture MFR = 5.0 g / 10min (JIS K 6758) Dense ^{= 0.90~0.91 g / cm 3 (JIS} K 6758) propylene copolymer (A-1) 75wt% propylene - ethylene rubber 25wt% (EP-O2P Japan Synthetic Rubber Co., Ltd.) C-2: propylene polymer / talc Mixture MFR = 8.0 g / 10min (JIS K 6758) Density = 0.90 to 0.91 g / cm ³ (JIS K 6758) Propylene copolymer (A-1) 80wt% Talc 20wt%

Example 1 An injection-molded plate (thickness of 3 mm, 100 × 200 mm) was prepared using the polyolefin resin shown in Table 1. This molded plate was preheated for 5 minutes in an electric heating type constant temperature bath kept at a predetermined temperature, then immersed in an organic solvent kept at 30 ° C for 5 minutes, and 1 minute later, a low pressure mercury lamp Special Light Source Co., Ltd.
It was placed in front of an ultraviolet irradiation device equipped with SUV-110), the distance between the light source and the surface of the molding plate was kept at 5 cm, and ultraviolet irradiation was performed for 5 minutes in an air atmosphere. The low-pressure mercury lamp used here is made of synthetic quartz having a light transmittance of 85% or more at a wavelength of 185 nm. Acrylic emulsion (Kanebo NSC Co., Ltd., Iodozol 2A644) was spray-coated on this molded plate at 200 g / m ² (wet), and 3 denier, 1.0 mm nylon pile (manufactured by Toray Industries, Inc.) was used to measure the distance between the electrodes. Electrostatic flocking was performed at 15 cm, flocking voltage of 50 KV, and flocking time of 10 seconds. Then, warm air dryer at 80 ℃ for 30
It was dried for 1 minute and then aged at room temperature for 48 hours to obtain a flocked molded article.
The flocked molded article was evaluated by a wear test according to JIS L1084. However, the radius of curvature of the friction element is 45 mm and the load is 500 gf.
After rubbing 4000 times at a stroke of 100 mm and a reciprocating speed of 30 times per minute, the surface condition was visually evaluated. In the same manner, a polyolefin resin molded product was brought into contact with an organic solvent and UV-irradiated to a molded plate, and then an acrylic emulsion (Kanebo NSC Co., Ltd. Iodosol 2A644)
Was spray-applied at 150 g / m ² (wet) and a cotton cloth was applied. After drying at 80 ° C. for 30 minutes in a warm air dryer and curing at room temperature for 48 hours, the 180 ° peel strength was measured.

The above measurement results are shown in Tables 1 to 4 in relation to the heating temperature of the molded plate. Table 4 is for comparison,
If the heating temperature of the molded plate is too low, the sufficient effect of improving the adhesiveness by the organic solvent cannot be obtained.

[0015]

[Table 1 (1)]

[0016]

[Table 1 (2)]

[0017]

[Table 2 (1)]

[0018]

[Table 2 (2)]

[0019]

[Table 3 (1)]

[0020]

[Table 3 (2)]

[0021]

[Table 4]

Reference Example Using an ABS resin (Styrac 100, manufactured by Asahi Dow Co., Ltd.), flocking and application of cotton cloth were performed in the same manner as in Example 1 except that the solvent was not contacted and the ultraviolet irradiation was not performed. It was
In this case, the flocking wear test result was ⊚, and the peel strength was 2.8 kg / 2.5 mm.

[0023]

EFFECTS OF THE INVENTION According to the present invention, strong adhesion can be achieved when a skin material is flocked or attached to a polyolefin resin molded product. It is comparable to conventional ABS resins and can be used practically without any problems. Further, in the present invention, since the molded product is preheated and brought into contact with an organic solvent to perform surface modification of the molded product, a high surface modification effect of the molded product can be obtained by a short-time organic solvent treatment, Moreover, since the entire organic solvent is not heated to a high temperature, the evaporation of the organic solvent is suppressed, and as a result, the deterioration of the working environment is prevented and the cost of the apparatus is reduced.

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Claims (4)

[Claims] 1. A surface of a polyolefin resin molded article is
After preheating at a temperature not lower than 5 ° C. and not higher than its melting point and contacting with an organic solvent near room temperature, the irradiation wavelength is 185 n
A method for decorating the surface of a polyolefin resin molded article, which comprises irradiating with ultraviolet rays having a main wavelength of m and attaching a flock or a skin material through a water-dispersible adhesive. 2. The surface decoration method for a polyolefin resin molded article according to claim 1, wherein the organic solvent is an aromatic hydrocarbon and / or a halogenated hydrocarbon solvent. 3. The surface decoration method for a polyolefin resin molded article according to claim 1, wherein the organic solvent is benzene. 4. The method for decorating the surface of a polyolefin resin molded article according to claim 1, wherein the organic solvent is a mixture of tetrachloroethylene and carbon tetrachloride.