JPH0325338B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention involves roughening the surface of the resin molded product after molding and removing part of the surface resin when producing a resin molded product by mixing resin and wood flour. The present invention relates to a method for decorating a resin molded article, which comprises performing a pretreatment to expose wood powder, and then applying an uneven pattern or a colored pattern to the upper surface of the resin molded article.

(Prior art) In a method for decorating resin moldings in which resin and wood flour are mixed and the surface is decorated, the mixed resin is extruded from a textured mold, etc., or during the rolling process using embossing rolls. Decorating.

(Problem) In the above method, since the decoration process is performed before the mixed resin has cooled down, the volume of the decorated part shrinks due to cooling after the decoration process, resulting in so-called "shrinkage" (shrinkage). mark) occurs. This "shrinking" causes the uneven pattern to lose its clarity, so-called sharpness, and to cause distortion in the pattern shape.

Furthermore, on the surface of the resin molded product, a surface resin is formed on the mixed wood flour, and there is a problem that the woody feel of the wood flour cannot be fully exhibited.

(Means for Solving the Problems) The present invention was invented to solve the above problems, and involves roughening the surface of a resin molded product cooled after the molding process, and removing the surface resin to form wood powder. By performing pre-treatment to expose the resin and then adding an uneven pattern such as a wood grain pattern, we can eliminate the "shrinkage" that occurs during molding, and further improve the wood texture of the wood grain pattern formed on the surface of the resin molded product. It is made larger and has a clear pattern.

The method for decorating a resin molded article of the present invention will be explained below.

(Example) Resin and wood flour are used as the main materials for forming a resin molded article.

As the resin, vinyl chloride resin (PCV), phenol resin, polyethylene, polypropylene, etc. are used.

Saw shavings or crushed wood chips are used as wood flour.
The moisture content of this wood flour is preferably about 5% in order to minimize the occurrence of shrinkage marks.

In the process of mixing the resin and wood flour, the resin is usually melted in a heated cylinder (barrel),
In this, 10 to 50% (preferably 25 to 30% by weight)
%) and knead.

Next, the molten resin is extruded from the heating cylinder by a screw, and a predetermined shape is given by a die (mold) at the tip. To form a sheet-like resin molded product, it is continuously molded into an endless long material while being cooled and solidified with water or air.

In addition to the extrusion molding method using a die, for example, calender molding may be used, in which the molten resin from a heating cylinder is rolled with hot rolls to form a predetermined shape, and then cooled in the same manner as described above.

Next, the surface of the resin molded product molded by the above-mentioned appropriate method is roughened and a part of the surface resin is removed. A specific method is to rotate a brush or buff roll and bring it into contact with the surface of the resin molding to smooth out any unnecessary unevenness that may have occurred during formation, as well as to avoid many fine scratches and to remove the surface resin of the resin molding. removed.

The main purpose of this process is to eliminate the surface gloss that occurs when it is rolled with a die or roll, but if a brush with an uneven tip is used, the roughness of the surface will vary, which will be explained later in the coloring process. It is possible to improve the wood texture due to color unevenness, etc. Furthermore, by removing the surface resin, the mixed wood flour is exposed on the sheet surface, further enhancing the wood texture and improving the penetration of the colorant. In particular, the wood powder exposed on the surface is not just long enough to visually appeal to the woody feel, but also increases the woody feel when touching the resin molded product.

After the above pretreatment step, a decoration step by embossing is performed. In embossing, a resin molded product is rolled between embossing rolls to continuously form an uneven pattern.

After the above-mentioned decoration step, a coloring agent is applied to make the wood grain pattern clear, and excess coloring agent on the surface is wiped off with a roll wrapped with nonwoven fabric or the like.

Pigments and dyes are usually used as coloring agents.

In addition, if the base material of the resin molded product mixed with a coloring agent in the heating cylinder is colored in advance in the same way as the surface coloring, the base material will not be exposed at the cut surface or damaged part of the surface of the resin molded product. However, the wood quality will not deteriorate.

The surface of the resin molded product formed through the above steps is subjected to a treatment such as a so-called top coat, and if necessary, it is cut to a required width and length to complete the entire molding process. Note that cutting can also be performed after extrusion molding and before the decorating process.

Although the method for decorating the surface of a resin molded article has been described with respect to the case where a wood grain pattern is applied, the gist of the present invention is not limited to this, and the same applies to the case where a resin surface that simply has a wood texture instead of a wood grain pattern is formed. It can be manufactured by the following steps.

(Effects) After being molded and cooled, all processing steps are carried out for decoration, so there is no "shrinking" and the shape of the pattern is always sharp, and the presence of the pattern is increased, even when used for example in building materials. It harmonizes with other wood-based materials and is widely used as a building material with great added value.

In this method, the process from forming a resin molded article to forming an uneven pattern using an embossing roll to applying and wiping off a coloring agent can be carried out continuously, resulting in an extremely efficient decorating process.

Claims (1)

[Claims] 1 Wood flour with a moisture content of about 5%, weight ratio of about 25 to 30%
After mixing with molten resin and forming a long sheet-like resin molding by extrusion or rolling, the resin molding is cooled, and then the surface of the resin molding is brushed with a rotating wire brush. The resin molded product is brought into contact with embossing rolls to smooth out unnecessary irregularities and roughen the surface, and the surface resin is removed to expose the wood powder on the surface.The resin molding is then rolled between embossing rolls to smooth out the necessary irregularities. A method for decorating the surface of a resin molded article, which comprises forming a pattern, then applying a coloring agent to the surface, and wiping off the excess coloring agent with a wiping roller.