JPS593142B2 - Manufacturing method for resin molded products with wood grain patterns on the surface - Google Patents

Description

[Detailed Description of the Invention] This invention provides a method for producing a resin molded product having a wood grain pattern on the surface;
In particular, the present invention relates to a method of manufacturing a thermoplastic resin molded product having a wood grain pattern on the surface by extrusion molding.

Conventionally, granules or powder of thermoplastic resin serving as a base material have been mixed with thermoplastic resin granules of the same type or a different type from the base resin, and colored darker or different than the base resin. A well-known method is to produce a molded product with a wood grain pattern by extrusion molding a material (hereinafter referred to as color pellets) added thereto, or by introducing color pellets from the vent hole of an extruder and extrusion molding.

However, according to the conventional method, small grain patterns that can be seen as cloud patterns are dispersed, and only a pattern with a single, fixed shape is obtained.

As a result of careful investigation into the main cause of such patterns, the inventors of the present invention found that the pattern on the surface of the molded product is simply due to the flow of molten resin within the extruder, and that the breaker plate has many holes in it. It has been found that among the circular small holes provided, the effect is caused by the channel holes drilled at the periphery of the molten resin channel.

In other words, the flow of resin that has passed through the breaker plate is almost unaffected by the rotating screw and forms a laminar flow, so the surface of the molded product is composed of the resin that has passed through the periphery of the breaker plate. It is something.

In this way, if flow paths of various shapes are provided in the vicinity of the breaker plate to regulate the resin flow and give a speed difference, the speed difference will be memorized until it exits the nozzle. - A pattern of any size can be created at any position on the surface of the molded product by providing a slit-like flow path of any length at an appropriate position along the outer edge of the resin flow path, including the plate. The present invention has been completed based on the discovery that it is possible to impart the above-mentioned properties.

The present invention aims to provide a method for producing a wood grain pattern of any size at any position on the surface of an extruded product, and the gist thereof is to Then, this resin and a different color resin are mixed and extruded,
In a method for manufacturing a molded product having a wood grain pattern, at least one slit hole is formed at a predetermined location in a resin flow path from the cylinder head of an extruder to the die land inlet along the outer edge of this flow path. The present invention relates to a method for producing a synthetic resin molded product having a wood grain pattern, which comprises attaching a flow regulating plate having a flow regulating plate and extrusion molding the product.

Hereinafter, the present invention will be described in detail in conjunction with the accompanying drawings.

The base resin and color pellet resin used in the method of the present invention may be the same or different, and such resins include styrene resins (e.g. polystyrene, rubber-modified polystyrene, ABS resin, etc.), vinyl resins (vinyl chloride resin, vinyl chloride copolymer resin, etc.), polyolefin (polyethylene, polypropylene, etc.), acrylic resin (methyl methacrylate resin, methyl acrylate resin, etc.)
Examples include.

Further, in the method of the present invention, any conventionally known type of extrusion molding machine can be used.

In the method of the present invention, a flow regulating plate having at least one slit hole is installed at a predetermined location in the resin flow path from the cylinder head of the extruder to the inlet of the die land.

A first specific example of this flow regulating plate is to use the breaker plate itself as a flow regulating plate.

FIG. 1 is a front view of an example of a flow regulating plate used in the method of the present invention, in which a breaker plate is used as the flow regulating plate.

In the figure, 1 is a flow adjustment plate that also serves as a breaker plate, 2 is a peripheral edge of this 1, 3 is a resin flow hole in the breaker plate, and 4 is a slit hole, which in this example is located in the upper half of the periphery. There are three.

The location where the flow adjustment plate 1 which also serves as the breaker plate is installed is the location where the breaker plate is normally installed.
That is, it is held between the cylinder head and the mouthpiece.

This situation is shown in FIG. FIG. 2 is a schematic longitudinal sectional side view of this part, in which the same reference numerals as in FIG. 1 refer to the same parts, 5 is a cylinder, and 6 is a base.

As shown in this figure, the slit 4 is positioned along the outer edge of the resin flow path so that the resin flowing between the slit 4 and the cylinder 5 does not stagnate, that is, no dead center is formed. The flow adjustment plate is arranged as follows.

As shown in FIG. 3, another example of a flow regulating plate is one that has a large cavity 9 in the center, is formed separately from the breaker plate, and is used only for flow regulation.

In the figure, 4 is a slit, 7 is a flow regulating plate, 8 is a peripheral edge of the flow regulating plate 7, and 9 is a passage through which the molten resin freely flows.

This flow regulating plate may be installed at any location between the cylinder head and the inlet of the die land.

That is, it may be located either upstream or downstream of the resin flow path when viewed from the breaker plate.

In the case of this flow regulating plate as well, as explained with reference to FIG. 2, it is necessary to install it so that no dead center is formed on the outer peripheral edge of the slit 4.

As mentioned above, when providing slits at the outer edge of the molten resin flow path, whether using a breaker plate or a separate flow regulating plate, the size should be determined according to the arc length and number of the slits. A wood grain pattern of various sizes and numbers appears on the surface of the molded product.

These results will be made clear from the Examples described below.

However, when using the flow regulating plate shown in Fig. 1 above and when using the flow regulating plate shown in Fig. 3, a grain pattern corresponding to the arc length and number of slits appears. However, in the former case, the individual curves of the wood grain pattern are clear and straight curves, and in the latter case, the individual curves are less sharp and have fine wavy curves than the former. .

Therefore, it is only necessary to select one of the cases according to each person's wishes.

The width of the slit is usually about 10 mrIL or less.

Of course, it may be 10 mm or more, but since the wood grain pattern only needs to appear on the surface of the molded product, there is no point in making it larger than necessary.

When the flow regulating plate shown in Fig. 1 also serves as a breaker plate, a small circular hole similar to that of a normal breaker plate is bored in the part other than the slit to create an appropriate back pressure inside the extruder. All you have to do is make it so.

Next, the present invention will be explained in detail.

Example 1 A breaker plate of an extruder having the shape shown in FIG. 4a was used as a flow regulating plate.

Note that Figure A is simplified and shows only the slits, and circular small holes in other parts are omitted from the figure.

This omission also applies to each of the following embodiments.

The outer diameter of the breaker plate is 55mm, and the inner diameter is 40mm.
.

The width of the slit is 6 mm, and the diameter of the small circular hole is 4 mm.

Using this flow adjustment plate, a single shaft with a diameter of 40 mm and an L/D ratio of 2
Using the extruder No. 2, a mixture of 100 parts of light yellow vinyl chloride resin (parts by weight, also in the following examples, parts represent parts by weight) and 3 parts of brown polymethyl methacrylate granules was extruded at the extrusion temperature. At 200℃, thickness 200μ
When extruded into a sheet, a sheet having a wood grain pattern shown in Figure 4 was obtained.

Example 2 A breaker plate having the shape shown in Fig. 5a (outer diameter 85 mm, inner diameter 65 mm, slit width 6 mm) was used as a flow regulating plate, and a single-screw extruder with a diameter of 65 m11 and an L/D ratio of 18 was used. Accordingly, when 5 parts of brown colored polystyrene granules were mixed at a ratio of 5 parts to 100 parts of pale yellow polystyrene and extruded into a sheet with a width of 400 mm at an extrusion temperature of 200°C, the resultant mixture was as shown in Figure 5. A sheet with the pattern shown was obtained.

Example 3 A breaker plate (outer diameter 85 mm) shown in FIG.
, inner diameter 65 mm, slit width 6 x m), 100 parts of black low-pressure polyethylene was supplied to one part of the hopper, and 2.5 parts of white low-pressure polyethylene was supplied to the ventro, At extrusion temperature 180℃, width 200℃
It was extruded into a sheet of 1tTIL.

As a result, a sheet having a wood grain pattern shown in FIG. 6 was obtained.

Example 4 A breaker plate of the shape shown in Figure T (outer diameter 97 mm, inner diameter 75 mm, slit width 6 ms), 100 parts of brown-colored ABS resin was placed in a part of the hopper, and brown-colored ABS resin was placed in one part of the hopper.
BS resin was supplied to the ventro at a ratio of 5 parts, and the extrusion temperature was 2.
The deck material was extruded at 30°C.

As a result, a deck material having a wood grain pattern shown in FIG. 7 was obtained.

Example 5 A breaker plate having the shape shown in Fig. 8a was installed in an extruder with two shafts rotating in opposite directions (screw diameter 75 mm), a vent type, and an L/D ratio of 18, and a polychloride colored pale yellow was prepared. 100 parts of vinyl is supplied to one part of the hopper, and 2 parts of brown colored polybutadiene is supplied from the vent.
A pipe with a diameter of 1001L and 11L was extruded at an extrusion temperature of 200°C.

As a result, a pipe having a wood grain pattern shown in FIG. 8 was obtained.

Example 6 An extruder with two co-rotating shafts (screw diameter 75 mm) and an L/D ratio of 16 was equipped with a breaker plate having the shape shown in FIG. 9a (outer diameter 97 mm, inner diameter 75 mm).

Using a slit width of 6 mm), 100 parts of light yellow colored polypropylene was supplied to one part of the hopper and 0.5 part of brown colored polypropylene was supplied to the vent hole, and the extrusion temperature was 240°C. (40m
When the plate was extruded to a size of 100 mm x 100 mm, a wood grain pattern as shown in Figure 9 was obtained on the surface and side surfaces of the plate.

Example 7 An extruder with two shafts rotating in opposite directions (screw diameter 75 mm) and an L/D ratio of 18 was equipped with a breaker plate shown in FIG.
m), 100 parts of brown vinyl chloride resin was fed into one part of the hopper, and 3 parts of brown vinyl chloride resin was fed into the ventro to extrude the irregular shaped product.

As a result, a molded article having a wood grain pattern shown in C on the opposite side of FIG. 10 b1 was obtained on the surface.

As described above, various wood grain patterns can be obtained by changing the number, size, and position of the slits.

These examples are cases in which slits are provided in the breaker plate, but it is also possible to install a flow regulating plate as shown in Figure 3 on the upstream or downstream side of the resin flow from the installation position of the breaker plate. Similar results can be obtained in terms of the size and number of wood grain patterns.

However, each curve in the pattern appears more blurry than in the case of a breaker plate, and the individual curves have a wavy shape.

Although various examples have been described above, the method of the present invention is not limited to these examples, and various other changes and modifications can be made within the scope of the claims.

[Brief explanation of drawings]

Fig. 1 is a front view of one example of the flow regulating plate used in the method of the present invention, Fig. 2 is a longitudinal cross-sectional side view of the installation part of the flow regulating plate, and Fig. 3 is another example of the flow regulating plate used in the method of the present invention. Figures 4 to 10 show each example of the method of the present invention, and in these figures, Figure A is a schematic front view of the flow regulating plate used, and Figures B and C are extrusion molded products. This is a drawing showing the wood grain pattern of. In the figure, 1 and 7 are flow regulating plates, 3 is a small circular hole for regulating the flow in the breaker plate, and 4 is a slit for regulating the flow.

Claims (1)

[Claims] 1. A method for manufacturing a molded product having a wood grain pattern by mixing a base resin and a resin of a different color by extrusion molding, from the cylinder head of the extruder to the inlet of the die land. A synthetic resin molded product having a wood grain pattern, characterized in that a flow regulating plate having at least one slit hole is attached along the outer edge of the resin flow path at a predetermined location of the resin flow path, and extrusion molding is performed. manufacturing method. 2. The method according to claim 1, wherein the flow regulating plate is a breaker plate provided with at least one slit along the outer edge of the resin flow path.