JP2002337179A - Resin molded article and molding method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin molded article and a molding method therefore which can hold the appearance of an exterior wall surface excellent without bringing about a cost increase. SOLUTION: The resin molded article is molded of a mixture which has resin pieces 5 obtained in a state of including coat pieces 21 by crushing used resin molded articles, and has a colored master batch 8 mixed in the resin pieces 5 in a prescribed weight ratio. The article is so molded that the exterior wall surface (f) constituting an outward appearance at least is covered with an emboss S formed in the shape similar to that of the coat pieces 21 or gas burn marks 22 exposed on the exterior wall surface (f).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded product formed by recycling a used resin molded product, and more particularly, to a resin molded product formed by mixing a used resin molded product with a coating film piece or the like. The present invention relates to a method for molding a resin molded product.

[0002]

2. Description of the Related Art In recent years, from the viewpoint of protecting the earth by effectively utilizing resources, once produced resin molded products are collected, pulverized and recycled as a new resin base material to form new resin molded products. Technology development is progressing. For example, vehicles use many resin parts. In particular, the bumper is made of a recyclable resin such as PP (polypropylene), so that it is collected and crushed to form a new resin base material. It is possible to recycle. However, when the resin base material containing the coating film is newly molded separately from the resin base material containing the coating base material, the coating applied to the surface of the bumper is mixed into the resin chip. For example, as shown in FIG. 12, a resin molded product 100 such as a bumper including the recycled material has a coating film piece 120 or a gas burn mark 130 exposed on a front wall surface 110 thereof, and thus has an appearance characteristic as a resin molded product. Is inferior.

[0003] In molding a resin molded product of a bumper, the recycled resin piece 5 is used to form a coating piece 120.
If the elimination is not performed, the workability is low and a problem arises in cost. Therefore, when a recycled resin piece is used as a resin base material, it is possible to mold a resin molded product which is usually provided at a position that is hardly noticeable, such as a resin undercover at a lower part of a vehicle body, a part of a footrest and a heel pad. It is possible. Alternatively, using a resin piece obtained by crushing a used resin molded product, forming the core of the resin molded product, and using a sandwich structure by integrally sandwiching the front and back of the core with virgin material It is known to recycle used resin molded products.

[0004]

However, in the recycling of used resin molded products, even if the resin molded products are molded in a portion that is hardly noticeable or that is not concerned about dirt, the use range is narrowed by itself. It is not in a favorable state for increasing the recycling rate of the used resin molded product.
Moreover, the appearance of the resin molded product is low when viewed directly. Furthermore, when a sandwich structure is adopted, a special molding mechanism that suppresses the incorporation of each resin in the core made of recycled material and the front and back parts of the virgin material is required, reducing overall molding workability and increasing molding costs. Will be invited. Therefore, a resin molded product and a molding method that can improve appearance characteristics without causing excessive cost increase, can be used without discomfort even in a relatively noticeable place, expand the range of use, and increase the recycling rate are desired. It is rare.

[0005] An object of the present invention is to provide a resin molded product capable of maintaining a good appearance of a front wall surface without increasing the cost, and a method of molding the same, based on the above problems.

[0006]

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that a used resin molded article is pulverized to obtain a resin piece obtained in a state including a coating film piece. Molded with a mixture having a colored masterbatch mixed with a resin piece at a predetermined weight ratio, and covered with a grain having at least the outer wall surface constituting the appearance having the same shape as a coating film piece or a gas burn mark exposed on the outer wall surface. It is characterized by being molded so that it can be processed. Since the front wall surface of the resin molded product is covered with a grain that has the same shape as the gas burn marks exposed on the front wall surface,
These gas burn marks are regarded as part of the appearance of the grain, and the colored masterbatch can form a surface-side colored resin layer below the surface of the front wall surface, and the surface-colored resin layer can be formed under the surface of the surface wall. The presence or absence of the coating film piece embedded in the resin molded article can be hidden and the appearance of the resin molded article can be improved even though the used resin molded article is recycled. Preferably, the resin molded product is injection molded by an injection molding machine supplied with the mixture. In this case, it is possible to easily mold the resin molded product so that the front wall surface is covered with the grain by the injection molding machine and the mold having the grain.

According to a second aspect of the present invention, a used resin molded product is pulverized to form a resin piece including a coating film piece, and a colored master batch is mixed with the resin piece to form a molding mixture. By using an injection molding machine supplied with the above mixture under predetermined injection conditions, a resin molding having at least the outer wall constituting the outer surface has a grain of the same shape as a coating film piece or a gas burn mark exposed on the outer wall. It is characterized in that the product is molded. A process of mixing a colored masterbatch with a resin piece and a process of molding a resin molded product having a coating film piece or a grain having a shape equivalent to a gas burn mark on a front wall surface by an injection molding machine and a molding die subjected to graining are employed. This makes it possible to improve the appearance of the resin molded product despite recycling the resin fragments including the coating film fragments obtained from the used resin molded products.

[0008] Preferably, the colored masterbatch is mixed with the resin piece at about 3% by weight. In this case, the surface-side colored resin layer can be formed under the surface of the front wall surface constituting the appearance of the resin molded product using a relatively small amount of the colored master batch, and the surface-side colored resin layer is buried under the surface of the front wall surface. It is possible to cover the existence of the coating film pieces to be formed, and to improve the appearance of the resin molded product despite recycling the used resin molded product. Preferably, the grain having the same shape as the gas burn mark may be formed at a depth of 20 μm or more. In this case, the gas burn marks have the same appearance as a grain having a depth of 20 μm or more, can be regarded as a part of the grain, and the appearance of the resin molded article can be improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a method for forming a footrest 1 which is a resin molded product as an embodiment of the present invention.
FIG. 2 shows the appearance of the footrest 1, and FIG. 3 shows an enlarged cross-sectional view. The footrest 1 is mounted on a floor in front of the driver's seat of a vehicle (not shown), and holds the foot in a fixed position when the driver steps on the footrest. 2 are formed in parallel, the downwardly extending piece 3 extends downward from the edge of the front wall surface f, and is fastened to the floor side by a bolt (not shown) through a part of the hole 4 of the front wall surface f. In this method of forming a footrest, a resin piece collecting step A for collecting a resin piece 5 obtained by pulverizing a used resin molded product, and a material kneading process in which an additive is mixed into the resin piece 5 to form a molding mixture. Step B and injection molding step C in which the molding mixture is melted by an injection molding machine to form a footrest with a molding die are performed in this order.

Here, in the resin piece collecting step A, the skin portion “part mainly composed of PP (polypropylene)” is separated and taken out from the collected used resin bumper 10.
Next, the collected resin part of the bumper is separated, the resin part is put into a crusher 6 and crushed, and the resin piece 5 of the crushed bumper is washed and dried, and the resin piece 5 (the coating film piece is removed). Including)
Collect. In the material kneading step B, the resin pieces 5 are 97% by weight.
And 3% by weight of a colored master batch 8 which is a pellet containing carbon as a pigment and polypropylene is supplied to a hopper 11 of an injection molding machine 9 and a mixture for molding is produced in a mixture producing section a of the injection molding machine 9. .

The injection molding machine 9 includes a cylindrical injection machine 14 for rotating the screw 12 in the cylinder 13 to inject the molten resin material, a nozzle 15 for connecting the cylindrical injection machine 14,
The runner block 16 includes a runner block 16 connected to the nozzle 15, and a split mold 17 that is detachable from the runner block 16. The cylindrical injection machine 14 has a mixture generation part a for mixing the resin material supplied to the hopper 11, a melting part b, and an injection part c for injecting the molten resin material into the mold 17. The split mold 17 is a metal mold.
72. In the injection molding process C, the resin is transferred between the inner wall of the cylinder 13 and the screw 1 according to the rotation of the screw 12.
The resin is melted and kneaded in the resin flow path between the two, the resin is caused to flow through the molten portion b, the nozzle 15, the runner block 16, and the gate 18, and the molten resin material is injected into the cavity 173 of the split mold 17. After injection of the resin, the split mold 17 is subjected to a predetermined cooling treatment, the mold is divided, and the footrest 1 is taken out. After a predetermined post-processing such as deburring, a resin molded product of the footrest 1 is obtained.

Here, the inner wall surface f1 of the movable mold 172 forms a molding portion of the front wall surface f of the footrest 1. The front wall f of the footrest 1 has a plurality of non-slip beads 2 formed in parallel, and has a texture (see FIGS. 3 and 10) S on the upper surface of each bead 2, and a bead having the texture S is formed. As described above, the inner wall surface f1 of the movable die is subjected to surface processing. The grain S here has a pear-skin pattern, and the depth t of the grain S
(See FIG. 3) is formed here to about 20 μm. As shown in FIG. 3, the footrest 1 formed in this manner has a surface-side colored resin layer 1 below the upper surface f of the surface.
No. 9 was produced, and the carbon colored area did not reach the inner area. This is because the solubility and chargeability of the colored master batch 8 are different from those of the recycled resin pieces 5 between the time when the molten resin is injected into the molding die 17 and then cooled and solidified. It is considered that the molten components of the colored master batch 8 gather below the surface wall f where the cooling proceeds. At this time, 3% by weight of the carbon contained in the coloring master batch 8 is concentrated and dispersed in the surface-side coloring resin layer 19, and the amount of carbon, which is a coloring matter used as a blind, is suppressed, thereby eliminating waste. .

Next, the footrest 1 has a texture S on a front wall surface f that constitutes the appearance thereof. In addition, as shown in FIG. 3, the coating film pieces 21 mixed in the recycled resin pieces 5 are dispersed in the surface-side colored resin layer 19 below the front wall surface f, and a part thereof is exposed to the surface side. However, the gas burn marks 22 caused by excessively high temperature inside the cavity during molding are formed on the surface wall f.
Scattered around. However, the depth t of the grain S on the front wall surface f of the footrest 1 is formed to be about 20 μm, which is the same depth as the depth t1 of the gas burn mark 22, and is formed by the grain S having the same shape as the gas burn mark. Has a shape that is indistinguishable unless it is visually observed. Further, the surface-side colored resin layer 19 is formed of black carbon, thereby covering the buried portion of the coating film piece 21, and has a shape indistinguishable unless visually recognized.

For this reason, the grain S is formed, and the front side colored resin layer 19 is colored black so that the front wall f of the footrest 1 is colored.
Is a resin molded product having an appearance in which only the grain S is molded, and can hide or obscure the coating piece 21 or the gas burn mark 22 and does not recognize the presence of the gas burn mark 22 and the coat piece 21. And the appearance can be improved. Next, the appearance characteristics of a comparative specimen equivalent to a resin molded article molded by the resin molding method according to the present invention and having the surface-side colored resin layer 19 with the grain S will be described. Here, description will be given using photographs (see FIGS. 4 to 11) of the respective front wall surfaces f of the comparative specimen corresponding to the resin molded article and other comparative specimens. Here, the outer shape of each comparative test piece is formed into a rectangular plate (110 mm × 85 mm) having a thickness of 6 mm. that time,
Eight types of comparative specimens, "1" (see FIG. 4) to "8", with the difference between the presence and absence of coloring and the presence or absence of grain S
(See FIG. 11) Table 1 shows the differences among the eight types of comparative specimens "1" to "8" together with the determination results.

[0015]

[Table 1]

Here, "2", "5"-
“8” uses the same material as the footrest 1 of FIG. 1, that is, 97% by weight of the recycled resin pieces 5 and 3
The injection molding machine 9 was used for molding by weight%. On the other hand, the comparative test pieces "1", "3", and "4" were molded by the injection molding machine 9 without using the colored master batch, using 100% by weight of the recycled resin pieces 5.

Furthermore, the comparative specimens "1" and "2"
None, “3” has a grain depth of 15μ, “4” has a grain depth of 2
Injection molding was performed at 0μ, “5” at a grain depth of 10μ, “6” at a grain depth of 15μ, “7” at a grain depth of 20μ, and “8” at a grain depth of 25μ. As shown in FIG. 4, the comparative specimen "1" had no surface-side colored resin layer and no grain, so that the presence of the coating film pieces 21 and the gas burn marks 22 were clearly distinguished, the appearance characteristics were low, and It was confirmed that the property was low. As shown in FIG. 5, the comparative specimen "2"
Is a surface-side colored resin layer and has no grain,
Although the presence of 1 was weakened, the presence of the gas burn marks 22 was clearly discerned, and it was confirmed that the appearance characteristics were low and the commercial value was low.

As shown in FIGS. 6 and 7, the comparative specimen "3"
And "4" have no surface-side colored resin layer and is grained, but the surface-side colored resin layer is absent and the coating film piece 21 is conspicuous,
In the case of “3”, the grain depth is 15 μm, and in the case of “4”, the grain depth is 20 μm. It was confirmed that the film was easily attached and had low appearance characteristics, resulting in low merchantability. As shown in FIGS. 8 and 9, the comparative specimens “5” and “6” had the surface-side colored resin layer, and the presence of the coating film piece 21 was weakened by the surface-side colored resin layer. Since the depth of 10 μm and “6” have a relatively small unevenness change due to the grain depth of 15 μm, the existence of the gas burn marks 22 can be easily distinguished, the appearance characteristics are low, and the commercial value is low. confirmed.

As shown in FIGS. 10 and 11, the comparative specimens "7" and "8" have a colored resin layer on the surface side, "7" has a grain depth of 20 μm, and "8" has a grain depth of 25 μm. Large change in target unevenness. In this case, since the depth of the normal gas burn mark 22 is about 20 μm, the grain S having the same shape as the gas burn mark 22 is formed, and the existence of the gas burn mark 22 is discriminated by the grain S. The appearance of the coating film pieces 21 is reduced by the surface side colored resin layer 19 (see FIG. 3), and the appearance characteristics are improved. It was confirmed that a resin molded product that did not cause a decrease was obtained. The comparative specimen "7" and the footrest 1 of FIG. 1 were molded by the same resin molding method, and like the comparative specimen "7", the footrest 1 of FIG. Has been improved, and it has become clear that sufficient merchantability can be ensured even when used in a place relatively easily visible.

The footrest 1 of the first embodiment has a molding resin mainly composed of PP (polypropylene). Alternatively, the footrest 1 may be molded mainly of PET (polyethylene terephthalate). well,
In this case, the same resin (polyethylene terephthalate) is used for the used resin bumper and the colored masterbatch to be collected in the resin piece supply step A, and the same molding method is used to form the surface of the embossed grain, It is possible to obtain a footrest with an improved appearance without being aware of the presence of a coating film piece or a gas burn mark.

In the material kneading step B, in addition to the used resin bumper and the colored master batch, a virgin material, a wax and the like may be selectively added to improve the product characteristics.

The footrest 1 of the first embodiment is injection-molded by an injection molding machine 9. Alternatively, when the resin molded product is a container-like product, blow molding (not shown) may be used instead of the injection molding machine. The above-mentioned resin piece supply process A using a machine
And a material kneading step B, and a blow molding step C ′ of melting the molding mixture with a blow molding machine and molding a container-like resin molded product with a molding die. Also in this case, similarly to the footrest 1 in FIG. 1, the surface S of the resin molded product has a depth of 20 μm or more on the surface of the resin molded product by the molding die of the blow molding machine.
Is formed to make it difficult to distinguish the gas burn marks 22, and to make it difficult to distinguish the coating film pieces 21 by the surface side colored resin layer 19, thereby improving the external appearance characteristics and using it in a place that is relatively easily visible. Thus, a container-shaped resin molded product (not shown) that does not cause a decrease in commercial properties can be obtained.

In the above description, the grain S having a matte texture is formed on the front wall surface f constituting the external appearance of the footrest 1, but instead of the matte texture, other textures having irregularities are formed. May be formed at a depth of 20 μm or more. In this case, too, the footrest 1 which is the resin molded product of FIG.
The same operation and effect as described above can be obtained.

[0024]

As described above, according to the present invention, the surface of the resin molded product is covered with the coating film exposed on the surface or the grain having the same shape as the gas burn mark. The gas burn marks are regarded as a part of the appearance of the grain, and the colored masterbatch can form a surface-side colored resin layer below the surface of the front wall surface, and the surface-colored resin layer can be formed below the surface of the surface wall. The presence or absence of buried coating film pieces or gas burn marks can be hidden or made inconspicuous, and the appearance of the resin molded product can be improved despite the recycling of the used resin molded product.

A method according to a second aspect of the present invention is a step of mixing a colored masterbatch with a resin piece, and forming a resin molded article having a coating film or a grain having the same shape as a gas burn mark on a front wall surface by an injection molding machine. By adopting the step of performing, the appearance of the resin molded article can be improved despite the fact that the resin piece including the coating film piece obtained from the used resin molded article is recycled.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of steps performed in a molding method for molding a resin molded product as one embodiment of the present invention.

FIG. 2 is a perspective view of a footrest which is a resin molded product as one embodiment of the present invention.

FIG. 3 is an enlarged sectional view taken along line II of FIG. 2;

FIG. 4 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen “1” molded by a method different from the method of molding a resin molded product as one example of the present invention.

FIG. 5 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen “2” molded by a method different from the method of molding a resin molded product as one example of the present invention.

FIG. 6 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen "3" molded by a method different from the method of molding a resin molded product as one example of the present invention.

FIG. 7 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen “4” molded by a method different from the method of molding a resin molded product as one example of the present invention.

FIG. 8 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen “5” molded by a method different from the method of molding a resin molded product as one example of the present invention.

FIG. 9 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen “6” molded by a method different from the method of molding a resin molded product as one example of the present invention.

FIG. 10 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen “7” molded by a method of molding a resin molded product as one example of the present invention.

FIG. 11 is an enlarged view (enlarged photograph) of a front wall surface of a comparative specimen “8” molded by a method for molding a resin molded product as one example of the present invention.

FIG. 12 is an enlarged cross-sectional view of a main part of a bumper formed by a conventional forming method.

[Explanation of symbols]

 5 Resin Piece 8 Colored Master Batch 9 Injection Molding Machine 10 Used Bumper 21 Coating Piece 22 Gas Burn Trace f Surface Wall A Resin Piece Collection Step B Material Kneading Step C Injection Molding Step S Grain

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F070 AA15 AE04 FA03 FB03 4F206 AA50 AC08 AF07 AH17 JA07 JQ81

Claims (2)

[Claims] 1. A mixture comprising a resin piece obtained by pulverizing a used resin molded product and containing a coating film piece, and a coloring master batch mixed into the resin piece at a predetermined weight ratio. A resin molded product characterized in that at least the outer wall surface constituting the outer appearance is molded so as to be covered with the above-mentioned coating film piece exposed on the outer wall surface or a grain having a shape equivalent to a gas burn mark. 2. A resin piece including a coating film piece is produced by crushing a used resin molded product, and the resin piece is provided with a "predetermined weight ratio".
Mixing the colored masterbatch to form a molding mixture, and applying the mixture under a predetermined injection condition, the injection coating machine supplied with the mixture, at least the outer wall surface constituting the appearance is exposed to the outer wall surface. Alternatively, a method for molding a resin molded product, which comprises molding a resin molded product having a grain having a shape equivalent to that of a gas burn mark.