JPH10195305A - Plastic molding and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plastic molding improved in fabricability (such as sawability and nailability), adherability, resistance to dimensional change due to temp., disposability, etc., and usable in a wide range of applications such as household electric appliances, building materials, and automotive materials and to provide a process for producing the same. SOLUTION: This molding is produced by mixing 100 pts.wt. plastic having a coefficient of linear thermal expansion as high as 1×10<-4> / deg.C or higher (e.g. a polyolefin resin) with 5-40 pts.wt. paper powder having a major diameter of 6mm or lower and contg. pulp having a fiber length of 1mm or lower, pelletizing resultant mixture, and molding the pellets by a known molding method. The surface of the molding is pref. decorated by direct or transfer printing or by lapping. When the molding is produced by injecting molding, it is pref. decorated by simultaneous printing and injection molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molded product and a method for producing the same, and more particularly, to a home appliance,
The present invention relates to a plastic molded product having improved processability, dimensional stability, and adhesiveness so as to be widely used in fields such as furniture, vehicle members, and architectural members, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, when plastic molded articles are used for architectural members, home electric appliances, vehicle members, and the like, they have the advantages of being water-resistant and hardly generating mold.
There are problems with workability such as difficulty in sawing or nailing at construction sites, etc.Depending on the material, the coefficient of linear expansion due to temperature changes is large, and dimensional stability is lacking. When it is used for fittings such as, for example, there are problems that opening and closing becomes difficult due to a change in temperature and that a gap is easily formed. In addition, regarding processing suitability and dimensional stability, similarly, when used for home appliances and vehicle components,
Problems such as deformation such as warpage, gaps, and adhesiveness when decorating the surface occur, and the range of use is limited.

There are many types of plastics in terms of material, and various types are used taking advantage of their respective characteristics. However, in recent years, recycling has been demanded due to the problem of waste disposal. Inexpensive and easily recyclable polyolefin-based resins have attracted attention. However, polyolefin-based resins have poor dimensional stability, in addition to the above-mentioned processability, and also have a problem in adhesiveness when decorating the surface of a molded product, and in fact, they are well accepted in the market. Not.

[0004] In order to solve such a problem, some attempts have been made to utilize plastics blended with wood flour. However, when wood powder is blended with plastic, the suitability for processing such as sawing and nailing is improved, but the surface of the molded product becomes blackish and becomes cloudy, which impairs the appearance of the molded product. However, even when the surface is decorated, there is a problem that the design is deteriorated due to the influence.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has been made to improve the common drawbacks of plastics, such as sawing and nailing, and to provide a polyolefin. When the coefficient of linear thermal expansion of a base resin or the like is as large as 1 × 10 ⁻⁴ / ° C. or more, it is reduced to improve the dimensional stability with temperature and to improve the adhesiveness of the surface of the molded product. Then, when ink, paint, or decorative sheet for decoration is laminated on the surface, it adheres with sufficient strength, and it can be easily crushed, incinerated or recycled even at the time of disposal. , Performance,
It is an object of the present invention to provide a plastic molded article which is excellent in processability and disposability and can be used in a wide range of fields, such as home appliances, furniture, vehicle members, architectural members, and a method for producing the same.

[0006]

As a result of intensive studies to solve the above-mentioned problems, the following objects have been achieved by the present invention. That is, the invention described in claim 1 comprises a plastic molded product characterized by being formed of a composition obtained by kneading paper powder with a plastic having a linear thermal expansion coefficient of 1 × 10 ⁻⁴ / ° C. or more. . In the present invention, the coefficient of linear thermal expansion is a value measured in accordance with JIS K6911, applicable clause 5.25.

By adopting such a configuration, even a plastic having a large linear thermal expansion coefficient of 1 × 10 ⁻⁴ / ° C. or more can be reduced in value, so that the size of the plastic molded product due to a temperature change can be reduced. The stability is improved, and the applicable range of applications can be expanded. In addition, by incorporating paper powder into the plastic, when the molded product is sawed, the resin does not stick to the saw blade due to frictional heat, and can be cut smoothly. Further, even when the molded article is nailed, the molded article is not broken because the distortion of the molded article is absorbed, and the workability of the molded article is improved. Further, the surface of the plastic molded product becomes porous and roughened, and at the same time, a part of the paper powder is exposed on the surface, so that the adhesiveness with a printing ink, a paint, or a decorative sheet is improved. Furthermore,
The cost is reduced by containing paper powder, and the disposability by incineration is also improved.

[0008] In the invention described in claim 2, the paper dust is:
The plastic molded article according to claim 1, wherein the length of the major axis is 6 mm or less, and the fiber length of the pulp contained is 1 mm or less. By using such paper powder, kneading with plastic becomes easy and uniform dispersion becomes possible, so that the effect of improving the plastic can be reliably obtained.

According to a third aspect of the present invention, the composition is characterized in that the paper powder 5
The plastic molded product according to claim 1, wherein the plastic molded product is formed in a mixing ratio of 40 parts by weight. By forming a plastic molded article with a composition having such a compounding ratio, while maintaining bending strength and other mechanical strength at a practical level, the dimensional stability, workability, and adhesion suitability are improved. And cost reduction,
Improved disposability can be achieved.

According to a fourth aspect of the present invention, there is provided the plastic molded product according to any one of the first to third aspects, wherein the plastic is a polyolefin resin. By adopting such a configuration, the dimensional stability due to the temperature, which is a drawback of the polyolefin resin, the suitability for processing, the suitability for adhesion are improved, and further, its advantages such as light weight, ease of molding, chemical resistance, Solvent resistance and disposability (easy volume reduction by pulverization, no harmful gas generated even when incinerated, no burning remains), recyclability, economy (low cost) Therefore, it can be used for a wide range of applications.

The invention described in claim 5 is the plastic molded product according to any one of claims 1 to 4, wherein the surface of the plastic molded product is decorated. As described above, by decorating the surface of the plastic molded product, in addition to the respective functions and effects described in the first to fourth aspects of the present invention, the appearance and the design are improved. It can be used preferably.

In the invention described in claim 6, the decoration is:
The plastic molded product according to claim 5, wherein the plastic molded product is decorated by a simultaneous painting method of injection molding. By adopting such a configuration, surface decoration is performed at the same time as molding, so that the production process is simplified and productivity is improved, and at the same time, heat and pressure required for decoration are automatically adjusted according to molding conditions. Is sufficiently added, the adhesiveness of the decoration applied to the surface of the plastic molded product is improved.

[0013] The invention described in claim 7 has a long diameter of 6 mm or less and is contained in 100 parts by weight of plastic having a linear thermal expansion coefficient of 1 × 10 ^-4 / ° C. or more. Pulp fiber length of 1mm or less 5 ~ 40
It comprises a method for producing a plastic molded product, which comprises preparing a composition kneaded in a mixing ratio of parts by weight, and molding the composition. By adopting such a manufacturing method,
A composition in which a required amount of paper powder is uniformly dispersed in plastic can be easily produced, and further, by molding the composition by a known molding method, processability such as sawing and nailing, A plastic molded product having excellent dimensional stability against temperature, surface adhesiveness, and the like, and excellent in disposability by pulverization or incineration can be produced at low cost and high productivity.

An eighth aspect of the present invention is a method for producing a plastic molded product according to the seventh aspect, wherein a polyolefin resin is used as the plastic. By adopting such a manufacturing method, it has been possible to improve dimensional stability against temperature, workability such as sawing and nailing, and surface adhesiveness, which were disadvantages of the conventional polyolefin resin molded product. Some lightness, ease of molding,
Excellent resistance, such as chemical resistance and solvent resistance, and recyclability (easy volume reduction by pulverization, no harmful gas generated by incineration, no burning) It is possible to produce a plastic molded product that can be used for a wide range of applications by making use of economy (low cost).

Further, the invention according to claim 9 is characterized in that the molding is performed simultaneously with the molding by using an injection molding simultaneous painting method in which a transfer film or a laminate film provided with a picture layer is placed in a mold. The method for manufacturing a plastic molded product according to claim 7 or 8, wherein the method is a decoration. By adopting such a manufacturing method, in addition to the functions and effects of the invention described in claim 7 or 8, the molding of the plastic molded product can be performed by a simplified manufacturing process and the surface can be freely designed. Since the decoration can be applied with good adhesiveness, it is possible to produce a plastic molded product having excellent design properties with good productivity.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention, such as a material used for a plastic molded product of the present invention and a manufacturing method, will be described.

(1) Material In the present invention, the plastic used is a plastic having a linear thermal expansion coefficient of 1 × 10 ⁻⁴ / ° C. or more. For example, in addition to polyolefin resins such as polypropylene, polyethylene and polybutene, Examples thereof include polyamide resins such as nylon 11 and nylon 12. Each of these resins may be used alone, but may be a mixed resin in which one or more other resins are blended, or may be a copolymer. By kneading paper dust with these plastics, as described above, the suitability for processing such as sawing and nailing, the suitability for adhesion, and the dimensional stability due to temperature can be improved. It should be noted that even if a plastic other than the above, that is, a plastic having a coefficient of linear thermal expansion of less than 1 × 10 ⁻⁴ / ° C. and having relatively good dimensional stability with temperature, sawing is performed by kneading paper powder. Since the suitability for processing such as pulling and nailing, the suitability for surface adhesion, and the like can be improved, plastics other than those described above can be used freely for such purposes.

The paper powder kneaded with the plastic is
White paper cutting waste generated by cutting or the like may be crushed and used, but a large amount of paper powder generated during milling processing (surface facing with a rotary blade) such as bookbinding can be used.
Paper powder itself is indefinite in shape, but its major axis is 6 mm or less,
The pulp preferably has a fiber length of 1 mm or less. When the major diameter of the paper powder is 6 mm or more, and the fiber length is 1 mm or more, the kneading property with the plastic decreases, the kneading requires time, and the paper powder is less likely to be further subdivided, so that it tends to be non-uniform, which is not preferable. . If the major diameter of the paper powder is 6 mm or less and the fiber length is 1 mm or less, kneading with plastic is possible, and the kneading is easier as the length is smaller. Use of such paper powder is advantageous in terms of effective use of waste and effective use of pulp resources, and it is inexpensive and easy to obtain raw materials.

(2) Manufacturing Method The above-mentioned plastic (resin) and paper powder are kneaded to produce pellets used for molding. As a device for kneading and pelletizing, it is efficient to use a device in which a pelletizer is incorporated in an intensive mixer (Banbury mixer) having a strong shearing force. By heating the resin with this device and kneading the paper powder in a softened state, the paper powder is further crushed and uniformly dispersed. The resin obtained by kneading the paper powder is cooled and pelletized through a pelletizer.

In kneading, the amount of paper powder to be added to the resin is in the range of 5 to 40 parts by weight of paper powder with respect to 100 parts by weight of resin. It is preferable in terms of improving the suitability for adhesion, improving the dimensional stability by lowering the coefficient of linear thermal expansion, and further improving the disposability and reducing the cost. When the added amount is less than 5 parts by weight, all of the above effects are insufficient,
If the amount exceeds 40 parts by weight, the workability, dimensional stability and cost reduction are obtained, but the smoothness of the molded product surface is significantly reduced by molding, and the mechanical strength is also reduced. Not preferred.

The pellets produced as described above can be molded by a molding machine to produce a plastic molded product.
The molding method itself is not particularly limited. For example, any of known methods such as injection molding, extrusion molding, compression molding, and transfer molding can be used, and a method suitable for a shape of a molded product is appropriately selected and used. Can be.

In the case of decorating the surface of a plastic molded product, usually, the surface is decorated in a separate step after molding, but when the molding method is injection molding, a known injection molding simultaneous painting method is used. Decoration can be performed simultaneously with molding. In the case of decorating the surface after molding of the molded article, a method of directly printing by known silk screen printing, gravure offset printing, tampo printing, etc., a method of transfer printing, or Japanese Patent Publication No. Sho 61-5895, Japanese Patent Publication No. 1-3333
No. 2, JP-B-3-2666, etc., any method such as a so-called wrapping film lamination method may be used, and embossing may be performed.

In particular, the lapping process involves laminating a roll-shaped film, which has been decorated in advance by printing or the like, on the surface of a molded product. A heat-sensitive adhesive may be applied, and this surface may be thermocompressed with a heating roll or the like according to the surface of the molded product. May be removed by hot-air drying or the like, and then directly bonded to the surface of the molded product by thermocompression bonding. When the surface of the molded article is decorated after molding as described above, the surface of the molded article is subjected to a known surface treatment such as corona discharge treatment, ozone treatment, flame (flame) treatment, primer coating, or the like. By performing the pretreatment, the adhesiveness of the decoration can be further improved or stabilized.

When using the simultaneous painting method of injection molding, a decorative film provided with a picture layer in advance by printing or the like is placed in a molding die, resin is injected, and molded simultaneously with molding. There is a method of decorating by decorating, or a method in which a transfer film provided with a picture layer is placed in a mold, and at the same time of molding, only the picture layer is adhered to the surface of the molded article and decorated. Can be used. By adopting such a method, the manufacturing process can be simplified and the productivity can be increased.

[0025]

The present invention will be described in detail below with reference to examples and comparative examples. However, the present invention is not limited to these examples.

Example 1 Polypropylene (hereinafter PP)
100 parts by weight of resin [Polypropylene J-700G manufactured by Idemitsu Petrochemical Co., Ltd.] is mixed with 20 parts by weight of a paper powder having a major axis of 6 mm or less and a fiber length of 1 mm or less in a blending ratio of 20 parts by weight. After heating and kneading with a mixer, the powder containing the paper powder is dispersed through a pelletizer.
P pellets were prepared. Using the above-mentioned pellets, a lid-shaped molded product having a thickness of 5 mm and a substantially rectangular flat portion having a width of 400 mm and a length of 600 mm formed on the upper portion by an injection molding method. Next, a wood-grain pattern was printed on the flat part of the above-mentioned molded product by a silk-screen printing method using a polyurethane-based ink to produce a plastic molded product having a wood-grain pattern in Example 1.

(Example 2) In the structure of the plastic molded product of Example 1, only the mixing amount of the paper powder was increased, and the amount of the paper powder was reduced by 3 with respect to 100 parts by weight of the PP resin.
Except that the pellets were prepared by mixing at a ratio of 0 parts by weight, all were processed in the same manner as in Example 1 to prepare a wood-molded plastic molded product of Example 2.

(Example 3) In the structure of the plastic molded product of Example 1, pellets were produced by replacing the PP resin kneaded with paper powder with a polyethylene (hereinafter PE) resin (polyethylene 110J manufactured by Idemitsu Petrochemical Co., Ltd.). Except for the above, all were processed in the same manner as in Example 1 to produce a wood-molded plastic molded article of Example 3. (The mixing ratio of PE resin and paper powder is 100: 20)

(Example 4) In the structure of the plastic molded product of Example 3, only the mixing amount of the paper dust was increased, and the amount of the paper dust was reduced to 100 parts by weight of the PE resin.
Except that the pellets were prepared by mixing at a ratio of 0 parts by weight, all were processed in the same manner as in Example 3 to prepare a wood-molded plastic molded article of Example 4.

(Comparative Example 1) In the structure of the plastic molded product of Example 1, all processes were the same as in Example 1 except that kneading of the paper powder with the PP resin was stopped and pellets of the PP resin alone were used. Thus, a plastic molded article having a wood grain pattern in Comparative Example 1 was produced.

(Comparative Example 2) In the construction of the plastic molded product of Example 3, all processes were the same as in Example 3 except that the kneading of the paper powder with the PE resin was stopped and the pellets of the PE resin alone were used. Thus, a plastic molded article having a wood grain pattern in Comparative Example 2 was produced.

(Comparative Example 3) As a molding pellet, an ABS resin having a coefficient of linear thermal expansion of less than 1 × 10 ⁻⁴ / ° C. [J
SR ABS57 Nippon Synthetic Rubber Co., Ltd.] Using a single pellet, molding and printing were carried out in the same manner as in Example 1 to produce a plastic molded article with a grain pattern in Comparative Example 3. As described above, in the injection molding of each of the plastic molded products of Examples 1 to 4 and Comparative Examples 1 to 3, the respective moldability was favorably molded without any problem.

(Tests and Results) The plastic molded products having the woodgrain pattern prepared in Examples 1 to 4 and Comparative Examples 1 to 3 prepared as described above, and the pellets separately prepared by injection molding the pellets of the respective blends. Measurements and tests of the following items were performed on the molded articles for testing dimensions, and the results are shown in Table 1.
Are shown together.

(1) Measurement of coefficient of linear thermal expansion For each molded product, the coefficient of linear thermal expansion was determined according to JIS K6911.
Measured in accordance with applicable clause 5.25.

(2) Processability of Molded Product Each plastic molded product was subjected to a sawing and nailing test, and the processability was evaluated according to the following criteria. ○: During sawing, the resin cuts smoothly without sticking to the blade,
No cracking or poor retention due to nailing. ×: When sawing, is the resin sticking to the blade and difficult to cut?
Or, those with cracking or poor retention due to nailing.

(3) Adhesive aptitude of molded product surface (Evaluated by adhesiveness of wood-grain pattern ink layer printed with polyurethane-based ink on the surface of each plastic molded product) Examples 1-4 and Comparative Examples 1-3 After leaving each of the wood-molded plastic molded products prepared in step 3 at room temperature for 3 days,
Cuts are made at intervals of 1 mm on the printed surface of each sample with a cutter in a grid pattern of eleven in length and width, and cellophane adhesive tape [Cellotape LD-18 made by Nichiban Co., Ltd.]
, And a 180 ° peel test was performed. The results are shown in Table 1 by symbols according to the following criteria. ○: No peeling of printed pattern ×: Peeling of printed pattern

(4) Measurement of bending strength The bending strength of each molded product was measured according to JIS K7203. Numerical values are shown in units of [kgf / cm ² ].

[0038]

[Table 1] (Note) In Table 1, parentheses indicate the mixing ratio of resin and paper powder.

As is evident from the test results shown in Table 1, paper powder was kneaded with PP resin, molded, and the grain pattern was printed on the surface thereof using a polyurethane ink. As can be seen from the comparison with the plastic molded product of Comparative Example 1 in which the paper dust was not kneaded, the linear thermal expansion coefficient of the plastic molded product was reduced from about 1/2 to 1/3, and the dimensional stability due to temperature was reduced. In addition to the improved properties, the workability of the molded product and the adhesiveness of the surface of the molded product were also improved.
Although the bending strength has been reduced, it is not particularly remarkable, and is of a level that does not cause any practical problems.

Further, the plastic molded products of Examples 3 and 4, which were similarly prepared by kneading paper powder with the PE resin, also showed linear heat as compared with the plastic molded product of Comparative Example 2 using only the PE resin. The expansion coefficient was reduced from about 1/2 to 1/4, the dimensional stability with temperature was improved, and the workability of the molded product and the adhesiveness of the molded product surface were also improved. Also in this case, the bending strength is reduced, but there is no practical problem. The plastic molded products of Comparative Examples 1 and 2 made of the PP resin or PE resin alone have large linear thermal expansion coefficients, and are inferior in both the workability of the molded products and the adhesiveness of the molded product surface. Not preferred. In addition, the plastic molded product of the ABS resin alone of Comparative Example 3 was:
Although the coefficient of linear thermal expansion is small and the adhesive suitability of the surface of the molded product is good, the workability of the molded product is inferior, and the overall plastic surface is inferior to the plastic molded products of the examples.

[0041]

As described in detail above, the invention described in claim 1 is formed of a composition in which paper powder is kneaded with a plastic having a coefficient of linear thermal expansion of 1 × 10 ⁻⁴ / ° C. or more. This is a plastic molded product characterized by the following features. By adopting such a configuration, the following effects can be obtained.

By kneading paper powder with a plastic having a large linear thermal expansion coefficient of 1 × 10 ⁻⁴ / ° C. or more,
The linear thermal expansion coefficient of the plastic molded product is reduced, and the dimensional stability with temperature is improved. Therefore, the plastic molded article can be used for a wider range of applications. Even when sawing a plastic molded product, the resin can be easily cut without sticking due to frictional heat. improves. By kneading the paper powder, the surface of the plastic molded product becomes porous and roughened, and at the same time, a part of the paper powder is exposed on the surface, improving the adhesiveness of the surface and facilitating surface processing such as decoration. become. By kneading the paper powder, the cost can be reduced and the disposability by incineration can be improved.

According to a second aspect of the present invention, paper powder kneaded with the plastic has a major axis of 6 mm or less,
In addition, the fiber length of the pulp contained is 1 mm or less, and the use of such a paper powder facilitates kneading with a resin and enables uniform dispersion. The effect of improving each performance of the plastic molded product can be more reliably obtained.

According to a third aspect of the present invention, a plastic molded product is formed from a composition obtained by kneading the paper powder in a mixing ratio of 5 to 40 parts by weight with respect to 100 parts by weight of the plastic. By adopting such a configuration,
While maintaining mechanical strength such as bending strength at a practicable level, the dimensional stability, workability, improvement of adhesive suitability,
In addition, cost reduction and improvement in disposability can be achieved.

According to a fourth aspect of the present invention, a plastic molded product is formed by using a polyolefin-based resin for the plastic. By adopting such a structure, the size of the polyolefin-based resin, which is a drawback of temperature, is a disadvantage. Stability, processability of molded products, and adhesive suitability have been improved. In addition, the advantages of ease of molding, chemical resistance, solvent resistance, light weight, and disposal, recyclability, economic efficiency, etc. are utilized. Therefore, the plastic molded product can be used for a wide range of applications.

According to the invention described in claim 5, the surface of the plastic molded product is decorated, whereby the appearance and design of the plastic molded product are improved, and the plastic molded product can be preferably used for a wider range of applications. Become like

According to a sixth aspect of the present invention, the decorating is a plastic molded article applied by a simultaneous painting method of injection molding, and by adopting such a decorating method, the surface is decorated simultaneously with the molding. Is performed, the productivity is improved, and at the same time, the heat and pressure required for decorating are sufficiently applied automatically according to the molding conditions, so that decorating with good adhesiveness can be obtained on the surface of the plastic molded product.

According to the seventh aspect of the present invention, the long diameter is not more than 6 mm and is contained in 100 parts by weight of the plastic having a linear thermal expansion coefficient of 1 × 10 ⁻⁴ / ° C. or more. Pulp fiber length of 1mm or less 5 ~ 40
A method for producing a plastic molded product, comprising preparing a composition kneaded in a blending ratio of parts by weight, and molding the composition. By adopting such a manufacturing method, mechanical strength such as bending strength is maintained at a practicable level, and dimensional stability by temperature is good, and the workability and adhesion suitability are excellent, and inexpensive incineration etc. It is possible to produce a plastic molded product having excellent disposability.

The invention according to claim 8 is the method for producing a plastic molded product according to claim 7, wherein a polyolefin resin is used for the plastic.
By adopting such a production method, the dimensional stability due to the temperature, processability, and adhesion suitability, which are disadvantages of the polyolefin resin, are improved, and at the same time, its advantages such as ease of molding, chemical resistance, and Solvent properties, light weight, and disposal (easy volume reduction by pulverization, no harmful gas generated even when incinerated, no burning remains), recyclability, economy (low cost) Since it is utilized, it is possible to produce a polyolefin-based resin molded product that can be used for a wide range of applications.

The invention according to claim 9 is characterized in that the molding is performed simultaneously with molding by using a simultaneous injection molding painting method in which a transfer film or a laminate film provided with a picture layer is placed in a mold. The method for manufacturing a plastic molded product according to claim 7, wherein the plastic molded product is decorated. By adopting such a manufacturing method, it is possible to form a plastic molded product and decorate the surface thereof with a free design with good adhesiveness in a simplified manufacturing process. In addition to the effects of the invention described in (1), a plastic molded product excellent in design can be produced with high productivity.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 23/00 B29C 67/16 // B29K 23:00 105: 16 511: 12 B29L 9:00

Claims (9)

[Claims] 1. A plastic molded product comprising a composition in which paper powder is kneaded with a plastic having a coefficient of linear thermal expansion of 1 × 10 ⁻⁴ / ° C. or higher. 2. The paper powder according to claim 1, wherein said paper powder has a major axis of 6 mm or less.
The plastic molded product according to claim 1, wherein the fiber length of the pulp contained is 1 mm or less. 3. The plastic molded article according to claim 1, wherein the composition is formed in a mixing ratio of 5 to 40 parts by weight of paper powder with respect to 100 parts by weight of the plastic. 4. The plastic molded article according to claim 1, wherein said plastic is a polyolefin resin. 5. The plastic molded product according to claim 1, wherein a decoration is applied to a surface of the plastic molded product. 6. The plastic molded product according to claim 5, wherein the decorating is performed by an injection molding simultaneous painting method. 7. A paper having a major axis of 6 mm or less and a pulp fiber length of 1 mm or less with respect to 100 parts by weight of a plastic having a linear thermal expansion coefficient of 1 × 10 ⁻⁴ / ° C. or more. A method for producing a plastic molded product, comprising preparing a composition in which powder is kneaded at a mixing ratio of 5 to 40 parts by weight, and molding the composition. 8. The method according to claim 7, wherein a polyolefin resin is used as the plastic. 9. The molding is performed simultaneously with molding using a simultaneous injection molding painting method in which a transfer film or a laminate film provided with a picture layer is placed in a mold. A method for producing a plastic molded product according to claim 7.