JPS636036A - Vacuum formed product having crest pattern - Google Patents

Abstract

PURPOSE:To increase productivity, to improve the degree of freedom of shaping and to obtain a crest pattern having a good product appearance, by molding a sheet of a composite resin composed of a polyolefin resin and a specified org. filler incorporated therein by using a crested vacuum forming mold. CONSTITUTION:A molded product having a crest pattern is obtd. by extruding a composite resin composed of a polyolefin resin and the following org. filler incorporated therein into a sheet and molding the resin sheet into a desired shape by using a crested vacuum forming mold. The org. filler is particulate cellulosic fillers and used in an amount of 5-20wt% based on the total amount of the composite resin. Polypropylene is particularly preferred as the org. filler from the viewpoints of the balance of cost, extrudability and mechanical strength. Examples of the particulate cellulosic fillers are woodmeal, rice hull, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a vacuum-formed product having a drawing pattern suitable for various automotive interior parts such as a wheel house trim and a rear/trunk room trim.

(Prior Art and its Problems) Recently, interior parts with curved shapes have come to be frequently used as various interior parts installed in the interior of an automobile.

This kind of interior parts are injection molded products of ABS resin or A
Thermoformed products made of BS resin sheets were the mainstream, but polyolefin resin materials such as polypropylene and polyethylene are suitable from a cost perspective, and vacuum forming is advantageous in terms of processing, and this vacuum forming mold If you carve a shibori pattern,
Vacuum forming can produce a drawing pattern comparable to injection molding, and vacuum forming has various advantages in that it can be performed at a much lower cost than injection molding.

In particular, these polyolefin composite resin plates mixed with inorganic fillers and extruded into sheet shapes are heated and softened, and then molded into the desired curved shape using vacuum forming. Its practical value is high in terms of strength.

However, the polyolefin resin plate or polyolefin composite resin plate has a large drawdown (a sagging phenomenon due to a decrease in viscosity due to preheating) during preheating, and usually 1 to 1.
5 seconds, and such a large drawdown limited the shape of the product, creating a problem that stable mass production was not possible.

Furthermore, polyolefin resin plates or polyolefin composite resin plates cool down quickly after preheating, so they tend to have uneven luster or uneven drawing due to the difference in mold contact time with the vacuum forming mold, and vice versa. It was also pointed out that it was difficult to form deep drawing patterns and was prone to poor appearance on the product surface.

(Objective of the Invention) This invention was made in view of the above-mentioned circumstances, and the object of the present invention is to suppress the rapid drawdown phenomenon, increase productivity, and improve the degree of freedom of modeling. It is an object of the present invention to provide a vacuum-formed product that has a drawing pattern that can be used in a variety of ways, and that also has a good product appearance.

(Structure and Effects of the Invention) In order to achieve the above object, the present invention provides a composite resin plate obtained by extruding a composite resin material in which an organic filler is mixed into a polyolefin resin into a sheet shape using a crested vacuum forming mold. In the vacuum-formed product having a drawn pattern formed into a shape, the organic filler is a granular cellulose-based filler, and its mixing ratio is 5 to 2 when the total is 100.
It is characterized by a maximum weight of 0%.

As the polyolefin resin, polypropylene,
Although polyethylene, polystyrene, etc. can be arbitrarily selected, polypropylene, which has been conventionally used, is most preferable because it has a good balance of cost, extrusion moldability, mechanical strength, etc.

In addition, as particulate cellulose organic filler, wood flour,
Using rice husk, etc., the mixing ratio of this cellulose-based organic filler to the polyolefin-based resin is 100% as a whole.
In this case, it is preferably 5 to 20 weight ffi%, and if it is less than 5%, the drawdown phenomenon described below cannot be suppressed and the heat storage property is not sufficient. Conversely, 20% by weight
If it exceeds the above range, there are problems such as the surface of the product becomes rough due to the presence of particulate cellulose-based acidic fillers such as wood flour and rice husk, the surface is highly receptive, and it is difficult to control the coloration of the product.

The above components (polyolefin resin and granular cellulose acid filler) are uniformly diffused and mixed using a tumbler mixer or Henschel mixer, then put into an extruder, melted inside the extruder, and shaped into a plate using a T-die. Extruded. This extruded composite resin plate can be used as a suitable vacuum forming material for the following reasons.

In other words, because the particulate cellulose organic filler is uniformly mixed and dispersed in the polyolefin resin, the polyolefin composite resin plate becomes uniformly softened during preheating, and the drawdown phenomenon can be prevented as much as possible ( It is possible to extend the time from the start of drawdown until the sheet is cut in 4 to 6 seconds), which has the advantage of not imposing restrictions on the product shape and allowing stable mass production.

Furthermore, due to the heat storage properties of this granular cellulose-based acidic filler, the speed at which the polyolefin-based composite resin plate itself is cooled and solidified by the vacuum molding mold is slowed down, so that the grain patterns etc. transferred to the product surface are It can be formed uniformly over the entire surface, resulting in an extremely good surface appearance.

In addition, because the drawdown phenomenon described above is small, the time difference between the center and end portions of the composite resin plate when they contact the vacuum molding die is small, and as a result, uneven gloss, drawing patterns, etc. are uniformly formed on the surface. It can be formed with a rough surface appearance.

As described above, in the vacuum-formed product with a drawing pattern according to the present invention, the drawdown phenomenon is suppressed by mixing a predetermined amount of granular cellulose-based organic filler, and the heat storage properties of the composite resin plate are increased, thereby making the product It has various effects such as an increased degree of freedom in shaping, stable mass production, and a significantly better surface appearance than conventional products.

(Description of Examples) A polyolefin composite resin plate having a thickness of 2 mm was obtained according to the compounding ratio shown in Table 1 below.

Table 1 Next, the physical property values of the polyolefin composite resin plates of each composition type were compared as shown in Table 2. Note that the wood flour used here is hardboard flour.

314-4-2) As a result, as is clear from Table 2, the vacuum-formed product according to the present invention has a lower specific gravity, higher impact resistance than polypropylene alone, and improved overall performance. Recognize.

Next, the reception properties for dividing the upper and lower parts of the granular cellulose-based organic filler according to the present invention will be explained.

That is, when the difference in surface color of various composite resin plates obtained using the compounding ratios shown in Table 1 is expressed as 8E, E = normal.
7 is considered the limit of susceptibility as a product, and from the viewpoint of susceptibility, the upper limit of granular cellulose-based organic filler is set at 20.
It was expressed as weight%.

In addition, if the particulate cellulose-based organic filler exceeds 20% by weight, the coloring cannot be controlled effectively if a coloring agent is mixed into the composite resin material.

In addition, the lower limit of granular cellulose-based filler is 5% by weight.
The reason for this is that if the amount is less than 5% by weight, the drawdown phenomenon of the composite resin plate cannot be suppressed to a small level, and heat storage properties cannot be imparted to the entire composite resin plate.

Based on the above study results, a polyolefin composite resin board in which 5 to 20% by weight of granular cellulose organic filler such as wood flour or rice husk is mixed into a polyolefin resin such as polypropylene has a high resistance to vacuum forming when softened. Drawdown phenomenon can be prevented as much as possible, cooling time can be slowed due to increased heat storage, good formability, transferability of drawing patterns, and surface appearance with no unevenness such as drawing unevenness or gloss unevenness. This is an extremely practical invention as it provides extremely good results.

Claims (1)

[Claims] (1) A vacuum-formed product having a drawing pattern in which a composite resin plate obtained by extruding a composite resin material in which an organic filler is mixed into a polyolefin resin into a sheet is molded into a desired shape using a crested vacuum molding mold, wherein the organic filler is a granular cellulose filler, and its mixing ratio is 5 to 2 when the total is 100.
A vacuum-formed product having a drawing pattern characterized by 0% by weight.