JP2903420B2 - Method for forming stone-like or cloth-like fine speckled pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides a beautiful stone-like or cloth-like texture on the surface of a resin molded product by uniformly dispersing carbon fibers in a thermoplastic resin together with dyes and pigments. The present invention relates to a method for forming a fine spot pattern, thereby obtaining a thermoplastic resin molded article giving a decorative feeling.

<Prior Art> Conventionally, various methods have been attempted for the purpose of imparting a speckled pattern such as a stone pattern or a cloth pattern to a thermoplastic resin molded product. As one of the methods, a spot pattern is formed on the surface of a molded product by melting and kneading several kinds of thermoplastic resins colored in different hues and molding them in an unevenly colored state before they are uniformly kneaded. There is a way to make it happen. However, kneading properties are improved in recent screw-type injection molding machines, hollow molding machines, and the like, and it is difficult to obtain a spot pattern by uneven kneading on the surface of a resin molded product using such a molding machine. Also,
It is well known that it is difficult to obtain an appropriately spotted pattern due to an inhomogeneous kneading state even if colored resins having incompatibilities with each other are used, and it is also well known that various problems occur in the physical properties of molded articles.

On the other hand, when mixing and dispersing different kinds of colored synthetic resin particles having a high softening temperature, the temperature range in the resin melt-kneading step is limited, and further, due to an unexpected temperature rise during kneading, the colored resin particles soften, It is difficult to obtain a stable pattern because the speckle pattern on the surface of the molded article flows.

For this reason, surface coating such as print coating, hot stamping, sinking, etc. has been used as a method of applying a spotted pattern such as stone texture and cloth texture to the surface of a molded product without giving various problems to the physical properties of the molded product. It is used in various fields.
However, since all of these techniques involve surface treatment as secondary processing, the production cost is high, and the ground pattern inside the molded product is easily exposed due to external damage, and there is a risk of abrasion and discoloration. It had various disadvantages.

Further, as a method of using a fibrous substance, JP-A-51-123
No. 248 is described about a thermoplastic resin composition having a fine spot pattern by uniformly dispersing the cellulosic colored fibers in the thermoplastic resin,
In this method, the fibers emerge in the form of lint on the surface of the colored molded product, so that fine spots are unlikely to occur, and it is difficult to sufficiently reproduce the decorative feeling of the stone-grain tone and the cloth-grain tone.

<Problems to be solved by the present invention> In view of such circumstances, expensive secondary processing or a mold
Easily and reproducibly gives a stone-pattern or cloth-tone dot pattern with a normal extrusion molding machine or injection molding machine without requiring any work on the molding machine, limiting the molding temperature range and unexpectedly increasing the temperature during molding There is a strong demand for the appearance of a thermoplastic resin composition which can improve poor reproducibility due to differences in kneading properties of molding machines and molding machines and can be adapted to various thermoplastic resins.

<Means for Solving the Problems> The inventors of the present invention have conducted intensive studies to obtain a thermoplastic resin composition which gives a spot pattern easily and with good reproducibility. As a result, the molding temperature of a normal thermoplastic resin (normally 150 to 300 ° C.) In the case of (1), if stainless steel or carbon fiber that does not soften and deform is used, and it is uniformly mixed and dispersed together with the dye and pigment in the resin, there are no such disadvantages as described above, and the stone tone is reproducible by ordinary extrusion molding or injection molding. The present inventors have found that a thermoplastic resin composition which can easily give a molded product having a spot pattern such as a cloth texture can be obtained, and have completed the present invention.

That is, the present invention provides a thermoplastic resin (A), a dye / pigment (B), and a fiber which does not soften and deform at the molding temperature of the thermoplastic resin, based on 100 parts by weight of the thermoplastic resin (A).
0.1 to 5 parts by weight, fiber diameter 5 to 30 μm, fiber length 0.1 to
A 10-mm carbon fiber (C) is plasticized at the molding temperature of the thermoplastic resin, kneaded, and molded to form a fine grained or cloth-like fine spot pattern on the surface of the molded article. It provides a way to:

The present invention also provides a thermoplastic resin (A) and a dye / pigment (B)
And 0.1 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin (A) as fibers which do not soften and deform at the molding temperature of the thermoplastic resin.
A carbon fiber (C) having a fiber diameter of 5 to 30 μm and a fiber length of 0.1 to 10 mm by weight is plasticized and kneaded at a processing temperature of the thermoplastic resin. It is intended to provide a method for producing a thermoplastic resin composition for molding a molded article having a fine-spot pattern of a tone or cloth texture.

Examples of the thermoplastic resin (A) used in the present invention include polystyrene, polypropylene, polyethylene, AS resin, ABS resin, acrylic resin, and vinyl chloride resin.
S resins are preferred.

The dye / pigment (B) is not particularly limited, and various dyes and pigments can be used.
Known organic pigments, inorganic pigments, extender pigments and the like can all be used. For example, azo-based, anthraquinone-based, thioindigo-based, perylene-based, perinone-based, quinacridone-based, phthalocyanine-based, dioxazine-based, isoindolinone-based organic pigments, carbon black, titanium oxide, red iron oxide,
Ultramarine, graphite, inorganic pigments such as other calcined pigments, tankal,
Extender pigments such as barium sulfate and talc may be mentioned, and these may be used alone or in combination of two or more.

As the fiber (C) which does not soften and deform at the molding temperature of the thermoplastic resin (A), the molding temperature of the thermoplastic resin (normally 150
Carbon fibers are indispensable because they do not soften or deform when left at −300 ° C.) because of their excellent extrudability.

As carbon fiber, the fiber diameter is 5 to 30 μm and the fiber length is 0.
It is appropriate to use the one having a diameter of 1 to 10 mm in that there is no entanglement between fibers, a beautiful spot pattern can be easily obtained, and there is no decrease in productivity or workability.

If desired, a stainless steel fiber can be used in combination with the carbon fiber.In this case, a stainless fiber having a fiber length of about 1 to 10 mm and a binder resin of 500 to 2
It is appropriate to use it after collecting 0000 pieces. As the binder resin, ethylene-vinyl acetate copolymer, polyethylene terephthalate, ethylene-ethyl acrylate copolymer, polyethylene wax, metal stearate and the like are used.

The amount of the fiber (C) is usually in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin, but when used as a master batch or the like, it is 3 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin. It is in the range of 30 parts by weight.

As a method of obtaining a molded article having a beautiful spot pattern,
For example, the fiber (C) is premixed with a part of the thermoplastic resin (A) to be a substrate to sufficiently entangle the fibers in advance, and then the remaining thermoplastic resin and the dye / pigment (B) are mixed. Then, this is directly supplied to a molding machine having high kneading performance to be molded, or melt-kneaded with a screw-type extruder or the like to form pellets, and then pelletized, or a method of dyeing with thermoplastic resin (A). After pre-mixing the pigment (B) and the fiber (C), the mixture is melt-kneaded by an extruder or the like, pelletized, and then formed into pellets. As a result, a stable and beautiful spot pattern can be formed on the surface of the molded article with almost no influence of fluctuations in the molding temperature.

In the composition of the present invention, various additives such as a surfactant, a dispersant, an antistatic agent, an antioxidant, an ultraviolet absorber, a metal soap, and a polyethylene wax may be added as necessary. it can.

<Example> Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. All parts and percentages in the examples are on a weight basis.

Example 1 100 parts of a polystyrene resin [Idemitsu Styrol NF-20 manufactured by Idemitsu Petrochemical Co., Ltd.] was mixed with pitch-based carbon fiber [Ltd.
Donac Carbo S-242, fiber diameter: 13 μm, fiber length: 0.37 mm) 0.4 parts and titanium oxide 0.6 parts, and further, magnesium stearate 0.2 parts as a dispersant, and premix for 3 minutes with a tumble mixer. went. Next, this mixture was melt-kneaded at 230 ° C. with a 40 m / m screw-type vented extruder to form pellets. The obtained colored thermoplastic resin composition pellets were used as molding materials for 75
Molding was performed at 230 ° C. using a ton screw type injection molding machine.
The surface of the obtained molded product had a beautiful stone tone with a black spot pattern on a light gray background.

Comparative Example 1 Coloring was performed in the same manner as in Example 1 except that sofu fiber (Suf Black manufactured by Kyoto Fiber Pulp and Paper Co., Ltd., fiber diameter: 15 denier, fiber length; 3 mm) was used instead of the pitch-based carbon fiber. Thermoplastic resin composition pellets were obtained and then molded in the same manner. In the obtained molded product, the fibers protruded in the form of lint on the surface, it was hard to say that it was a fine speckled pattern, and the stone-like decorative feeling was poor.

Example 2 Pitch-based carbon fiber [Donnacarbo S-342, manufactured by Donac Co., Ltd., fiber diameter: 18 μm] relative to 100 parts of a polypropylene resin [Hypole J840F manufactured by Mitsui Petrochemical Industry Co., Ltd.]
m, fiber length: 0.5 mm] 1.3 parts, titanium oxide 0.52 parts, calcined yellow pigment 0.12 parts, red iron oxide 0.01 parts, and magnesium stearate 0.3 parts are further added, and premixed for about 3 minutes by a tumble mixer. Was. Then, mix this mixture with 40
The mixture was melt-kneaded at 220 ° C. by a m / m screw-type vent extruder and pelletized. The obtained colored thermoplastic resin composition pellets were molded at 220 ° C. using a 75-ton screw injection molding machine as molding materials. The surface of the obtained molded article had a beautiful cloth tone having a black spot pattern on a beige background.

Example 3 0.2 part of pitch-based carbon fiber (Donacarbo S-242), 1.5 parts of a bundled tip of a stainless steel fiber (susmix fiber bundled tip) and 0.6 part of titanium oxide were added to 100 parts of a polystyrene resin (Idemitsu Styrol NF-20). In addition, 0.35 parts of magnesium stearate was further added as a dispersant, and the mixture was preliminarily mixed by a tumble mixer for 3 minutes. The following procedures were the same as in Example 1 to obtain a colored molded product. The surface of this molded product had a beautiful stone tone with a black spot pattern on a light gray background.

<Effects of the Invention> By using the pattern forming method of the present invention, it is possible to easily obtain a resin molded product having a spotted pattern such as a stone-grained tone or a cloth-grained tone, which has been difficult to date, with good reproducibility. There are also the following advantages.

Since the fiber does not melt at the molding temperature of the thermoplastic resin, it can be used at a wide range of molding temperatures and can be applied to various resins.

Since the influence of the fluctuation of the molding temperature on the pattern is small, there is no problem even in the case of unexpected temperature rise.

There is no need to cause poor dispersion and the reproducibility of molded products is high.

By simply mixing and dispersing uniformly with a usual extrusion molding machine or injection molding machine, a stone-grained or cloth-grained pattern can be easily provided.

There is no need for secondary processing.

The effect on the physical properties as in the case of mixing different resins is small.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Junichi Kumabe 3-2-2-22 Kamogahara, Higashinada-ku, Kobe-shi, Hyogo (56) References JP-A-59-196333 (JP, A) JP-A-61-190557 (JP, A) JP-A-63-12663 (JP, A) JP-A-1-301748 (JP, A) JP-A-2-178356 (JP, A) JP-A-2-36266 (JP, A) No. 61-10502 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08K 3/00 C08K 5/00 C08K 7/06 C08L 101/00

Claims (2)

(57) [Claims] 1. A thermoplastic resin (A), a dye / pigment (B),
As a fiber that does not soften and deform at the molding temperature of the thermoplastic resin, carbon fiber having a fiber diameter of 5 to 30 μm and a fiber length of 0.1 to 10 mm is used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin (A). (C) plasticizing at the molding temperature of the thermoplastic resin, kneading and molding, and forming a fine spot pattern of stone-like or cloth-like on the surface of the molded product. 2. A thermoplastic resin (A), a dye / pigment (B),
As a fiber that does not soften and deform at the molding temperature of the thermoplastic resin, carbon fiber having a fiber diameter of 5 to 30 μm and a fiber length of 0.1 to 10 mm is used in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin (A). And (C) plasticizing at a processing temperature of the thermoplastic resin and kneading the mixture, wherein the thermoplastic resin composition for forming a molded article having a fine-spotted or cloth-like fine spot pattern on the surface thereof. Manufacturing method.