JPH1135689A - Production of resin composition and production of resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the economical obtaining of subject lightweight composition, excellent in strength and having a low calorie of combustion heat at the time of incineration without damaging an incineration furnace by kneading natural or synthetic fibers with a synthetic resin, providing resin particles and then pulverizing the resultant resin particles. SOLUTION: This composition is produced by kneading natural or synthetic fibers with a synthetic resin so as to provide (90/10) to (30/70) weight ratio of the synthetic resin/fibers, providing resin particles and then pulverizing the resultant resin particles. Shredded pieces or roughly crushed materials of waste paper or old clothes can be used as the fibers. The shredded pieces of the fibers preferably have 3 mm×3 mm to 1 mm×1 mm size. A particle diameter of passing about 20 mesh is preferred as the particle diameter of the roughly crushed materials. For example, polyethylene and polypropylene are cited as the synthetic resin. The synthetic resin particles are preferably finely pulverized at normal temperatures by using a usual pulverizer when the fiber content is high. When the fiber content is low and the resin is soft, the pulverization is preferably carried out at low temperatures.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin composition and a method for producing a resin molded product, and more particularly, to an incinerator having excellent strength and light weight, and low heat of combustion during incineration. The present invention relates to a method for producing a tree resin composition and a method for producing a resin molded product that are not damaged.

[0002]

2. Description of the Related Art Conventionally, various molded products made of various synthetic resins have been produced and used in large quantities. Various fillers are added and mixed to these resin molded products according to various purposes. There are various purposes for adding the filler, and one of them is to reduce the calorie burned during incineration after use of the molded product. That is, since the heat of combustion of the synthetic resin is usually very high, the incinerator may be damaged at the time of incineration. Therefore, an inorganic filler such as calcium carbonate is added to reduce the heat of combustion. However, when a molded article containing a large amount of the above-mentioned inorganic filler is incinerated, a large amount of ash remains after incineration, which causes another problem of treating this ash.

[0003]

As a method of solving the above-mentioned problems, there is a method of using wood powder, paper powder or the like as a filler, but organic substances such as wood powder and paper powder are mainly composed of cellulose. Therefore, it is difficult to pulverize, and when a large amount of these wood powder and paper powder are mixed with the synthetic resin, the mixing properties of the two are poor, and there is a problem that the quality of the obtained molded product is significantly reduced. . When a strong kneader is used to improve the kneading properties, frictional heat is remarkably generated, and there is a problem that ignition occurs. When a small amount of wood powder, paper powder, or the like is mixed, the above problem does not occur, but in this case, the combustion heat at the time of incineration cannot be reduced.

Further, conventional synthetic resin films are used in large quantities as various packaging materials such as shopping bags and garbage bags, as agricultural films, and the like. If these materials are abandoned and not collected, they are naturally decomposed. It has no properties (microbial degradability) and is a major cause of environmental pollution. The inventor has
For the purpose of solving the above-mentioned problems, a method of preparing a film or the like by pulverizing waste paper and kneading it with a synthetic resin has been proposed before (see Japanese Patent Application No. 6-337622).

The above-mentioned method by the present inventor is an effective method for solving the problems of the prior art. However, the pulverization of waste paper requires a lot of energy, and the waste paper fine powder is extremely lightweight and bulky. Therefore, it is difficult to mix a high concentration into the synthetic resin in a weight ratio. Especially when forming into a thin film later, coarse particles are not allowed to be present in the used paper fine powder, and the classification of the used paper fine powder is costly. Was high. In particular, when the used paper is a certain material such as newsprint, the above problem is not significant.However, when the used paper is a mixed kind of used paper, it is possible to produce a used paper fine powder containing no coarse particles. An object of the present invention was to provide a resin composition and a resin molded product which are excellent in strength and light in weight, and have low calorie in combustion heat and do not damage an incinerator. It is.

[0006]

The above object is achieved by the present invention described below. That is, the present invention provides a method for producing a fiber-containing resin composition, which comprises kneading natural or synthetic fibers and a synthetic resin into resin particles, and pulverizing the resin particles, and a method for producing a resin molded product. is there. According to the present invention, fibrous materials such as waste paper are shredded or coarsely pulverized without being finely pulverized, and the chopped or coarsely pulverized fibers are kneaded with a resin to form resin particles. By,
The resin composition containing fibers in the finally pulverized state can be obtained without requiring a difficult fiber pulverization step.

Although it is difficult to finely pulverize the fiber itself, it is easy to shred or coarsely pulverize the fiber, and it is also easy to knead the fine fragment or coarsely pulverized product with a resin. Since the thus chopped or coarsely crushed fiber is hardened by the resin, the bulkiness of the fiber is eliminated, and the finely chopped or coarsely crushed fiber is hardened by the resin. Can be easily pulverized together with the resin. Therefore, even if there are some coarse particles or foreign matter in the chopped or coarsely pulverized fiber, a composition comprising the finely pulverized fiber and the resin, which is finely pulverized together with the resin when the resin particles are pulverized. It can be. Therefore, by using this resin composition, for example, molding of a thin film or the like can be performed without any problem.

[0008]

Next, the present invention will be described in more detail with reference to preferred embodiments. The synthetic resin used in the present invention is a general-purpose resin such as low-density polyethylene, high-density polyethylene, polyvinyl chloride, polystyrene, polypropylene, and polyethylene terephthalate, particularly when used for packaging films such as garbage bags. And low-density polyethylene are preferably used. When a biodegradable resin is used as the resin, the biodegradability of the obtained film is further improved, and it is particularly useful as an agricultural film.

The fibers used in the present invention include papers such as waste paper,
Waste of woven or non-woven fabrics generated in the used clothing, spinning and woven industries, wood flour, woody materials such as sawdust, plant fibers such as straw, etc. can be used. , Such as a commercially available shredder or a Super Cyclone crusher manufactured by Murata Co., Ltd. At the time of this shredding or coarse pulverization, it is not necessary to finely pulverize the fiber, and it may be fine or coarse pulverization that can be mixed with a synthetic resin powder or pellets.
× 5mm to 0.5mm × 0.5mm, preferably 3mm
× 3 mm to 1 mm × 1 mm, and 5 for grinding
Any fine pieces or coarsely pulverized material having a mesh pass, preferably about 20 mesh passes may be used.

[0010] With such fine pieces or coarsely crushed products,
It can be mixed with synthetic resin powder and pellets of similar particle size, since it forms a fluffy dust and does not become excessively bulky. For mixing, a Henschel mixer or a tumbler mixer, which is generally widely used in powder mixing, can be used as it is. The mixing ratio is not particularly limited, but in order to effectively achieve the object of the present invention, the ratio between the synthetic resin and the fiber is 95 / weight ratio (synthetic resin / fiber).
It is in the range of 5-20 / 80, preferably 90 / 10-30 / 70.

In the present invention, it is necessary to heat and knead the mixture of the above-mentioned fine fiber fragments or coarsely pulverized material and the synthetic resin to form pellets. This kneading can be easily performed by using an extruder usually used for pelletizing a synthetic resin. The size of the pellet to be formed is not particularly limited, and may be the same as the pellet of a general synthetic resin.

In the present invention, the finely divided or coarsely ground fiber-containing resin particles obtained as described above are finely ground to finely pulverize the finely or finely ground fiber fixed in the resin particles. It has the greatest features. Due to this feature, the finely pulverized fibers are hardened by the resin, so that they do not become fluffy and dusty, but rather are fine particles having a specific gravity somewhat lower than that of the resin used in the composition. In the case of pulverization, when the fiber content is high (for example, 40% by weight or more), fine pulverization can be performed at room temperature by a normal pulverizer such as a jet mill or a polishing pulverizer.

On the other hand, when the fiber content is low and the resin is soft, it is preferable to pulverize at low temperature, for example, freeze pulverization. In the case of low-temperature pulverization, the fiber-containing resin particles are cooled to a temperature equal to or lower than the glass transition temperature of the resin, for example, to about −10 ° C. to −100 ° C. with liquid nitrogen, and mechanically pulverized. Done by For this pulverization, many commercially available frozen pulverizers can be used as they are. The particle size of the crushed resin particles is 10 to 50.
It is preferably in the range of about 0 μm.

In the finely pulverized material obtained as described above, the fine fiber fragments or coarsely pulverized material surrounded by the resin are also pulverized at the same time. Does not cause any problems. This finely pulverized material can be used as it is for a molding material such as a film, and may be further pelletized by an extruder or other means if necessary in terms of handleability. For example, when a film is formed using the powdered resin composition, when the content of the fiber in the resin composition exceeds 50% by weight, the fiber content is 5 to 50%.
Diluted with natural resin to give a weight percent
The film can be formed on a film having an arbitrary thickness, for example, about 10 to 100 μm, using a conventional technique such as an inflation method or a T-die method. The film thus obtained is suitable as a raw material for shopping bags, garbage bags, agricultural films and the like in retail stores.

The resin composition of the present invention may include other additives such as a colorant, an antioxidant, an antistatic agent, and other fillers as long as the object of the present invention is not hindered. . Further, the resin composition of the present invention is not limited to film molding, and can be used as a molding raw material in various injection moldings, extrusion moldings, and other molding methods.

[0016]

Next, the present invention will be described more specifically with reference to examples and comparative examples. In the following, "parts" and "%" are based on weight unless otherwise specified. Example 1 200 parts of coarsely crushed waste paper (10 mesh pass) and 100 parts of low-density polyethylene resin powder (10 mesh pass) obtained by crushing using a matcha crusher Super Cyclone manufactured by Murata Co., Ltd. After light mixing with a mixer, a 40 m / m extruder (L / D = 28, CR =
3.1, screw with dull mage, cylinder temperature 1
Kneading at 30 ° C. and a screw rotation speed of 70 rpm)
The resin particles were pelletized. The resin particles were finely pulverized by a grinding pulverizer to obtain a resin powder having a particle size of about 50 μm.

Next, 10 parts per 100 parts of the above resin composition
0 parts of a natural resin, and the mixture was put into an inflation apparatus (40 m / m extruder, inner diameter of 50 m / m inflation die, cylinder temperature of 140 ° C., screw rotation speed of 60 rpm) to give a light gray film having a thickness of 50 μm. A polyethylene film (with a fiber content of 33%) was obtained. The surface of this film is smooth and strong enough,
The heat of combustion was less than about 7,000 Kcal.

Example 2 In Example 1, the used newspaper was shredded to 1 mm.
A polyethylene film having a thickness of 20 μm was obtained in the same manner as in Example 1 except that paper shredded to × 1 mm was used. Examples 3 to 8 and Comparative Example 1 Several fiber shreds or coarsely pulverized products were prepared in the same manner as in Example 1 or 2, and these fiber shredded or coarsely pulverized materials were used. In the same manner as in Example 1, a resin composition and a film of the present invention were produced. The physical properties of these films are shown in Table 1 below.

[0019]

[Table 1] * 1: Biodegradable (film was very fragile when taken out after burying in field soil for 6 months).

[0020]

According to the present invention as described above, a resin composition and a film which are excellent in strength and light in weight, have low calorie during combustion and do not damage the incinerator, and are provided with excellent economic efficiency. .

Claims (10)

[Claims] 1. A method for producing a fiber-containing resin composition, comprising kneading natural or synthetic fibers with a synthetic resin to form resin particles, and pulverizing the resin particles. 2. The fiber according to claim 1, wherein the fiber is a fine or coarsely crushed product of paper, a fine or coarsely crushed material of woven or non-woven fabric, a finely divided or coarsely crushed plant or a coarsely crushed rice husk. A method for producing a fiber-containing resin composition according to the above. 3. The fine particle or coarsely crushed fiber has a particle size of 5
The method for producing a fiber-containing resin composition according to claim 2, wherein the size is 5 mm x 5 mm or less or 5 mesh passes. 4. The method for producing a fiber-containing resin composition according to claim 1, wherein the pulverization of the fiber-containing resin particles is performed at a normal temperature or a low temperature. 5. The method for producing a fiber-containing resin composition according to claim 1, wherein the weight ratio (synthetic resin / fiber) of the synthetic resin to the fiber is in the range of 95/5 to 20/80. 6. The particle size of the crushed resin particles is from 10 to 50.
The method for producing a fiber-containing resin composition according to claim 1, wherein the thickness is 0 µm. 7. The method for producing a fiber-containing resin composition according to claim 1, wherein the synthetic resin is polyethylene, polypropylene, polyester, a biodegradable resin, or a mixture thereof. 8. A method for producing a resin molded article, comprising molding the fiber-containing resin composition according to claim 1. 9. The method for producing a resin molded product according to claim 8, wherein the molded product is a film. 10. The method according to claim 9, wherein the film contains 5 to 50% by weight of a fiber component.