JPH047373B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a resin composite composition using paper, particularly waste paper and paper scraps, and is advantageous for use in industrial materials such as car air conditioner casings. . [Prior Art] In recent years, resource and energy conservation has been studied in various fields, and the results have been shown to be effective. Among these, various studies have been made regarding methods for producing resin composite compositions using paper, particularly waste paper and waste paper as waste. When paper is mixed with resin and used as a filler, plant fibers mainly composed of cellulose serve as a reinforcing material, and molded products using this resin composite composition can be expected to have good mechanical properties. Plant fibers mainly composed of cellulose obtained from paper are inexpensive and good fillers. However, vegetable fibers mainly composed of cellulose have the disadvantage that they easily break and become short fibers when subjected to large shearing forces, and are subject to thermal deterioration when exposed to high-temperature atmospheres. Therefore, when producing a resin composite composition using paper, it is necessary to be careful of such drawbacks. However, conventional methods for producing resin composite compositions using paper, such as those described in Japanese Patent Publication No. 56-9576, do not take such drawbacks into consideration at all. For example, in the manufacturing method described in the above publication, waste paper is crushed into pieces with a diameter of about 3 to 6 mm, a thermoplastic resin is added, and high-speed stirring is applied while keeping it warm, the resin is melted, and the waste paper is crushed in the molten resin phase. The method used is to perform beating and impregnate the beaten waste paper fibers with resin to form a composite material. When a resin composite composition containing waste paper is formed by such a method, the thermoplastic resin is first added to the coarsely crushed waste paper and then stirred at high speed while keeping it warm, and the waste paper is mixed in the molten resin phase. Due to the beating process, significant shear forces and heat are applied to the waste paper before the composite composition is formed.
As a result, the waste paper is defibrated into plant fibers mainly composed of cellulose, but due to excessive shearing force and heat, the fibers are subsequently broken and become short fibers.
It also deteriorates due to heat. Plant fibers mainly composed of cellulose that have been shortened and heat eroded cannot fully exhibit their properties as a reinforcing material in a resin composite composition. For example, when a molded article is molded using such a molding material using injection molding, which is currently the most commonly used method, thin and complicatedly shaped articles cannot be ejected from the mold. Therefore, up to now, it has been limited to a narrow range of applications such as vacuum forming. [Object of the Invention] Therefore, the present invention defibrates paper in advance to form plant fibers mainly composed of cellulose, impregnates this with a molten resin, and then cools it to make the plant fibers into short fibers. , which is designed to prevent thermal deterioration. [Configuration of the Invention] The configuration of the present invention includes the steps of defibrating paper and impregnating the defibrated material with molten resin. In the present invention, the step of defibrating paper involves a method of defibrating the paper by first cutting the paper into small pieces with a diameter of about 3 to 6 mm and stirring them at high speed with a high-speed fluid mixer;
Alternatively, there are two methods: defibrating small pieces of paper using a pulverizer such as a turbo mill, or defibrating paper using a pulverizer such as a high-speed fluid mixer or a grain mixer without cutting the paper into small pieces. It is valid. Furthermore, in all of these methods except for the method using a turbo mill, by adding an appropriate amount of water for defibration, the defibration condition is improved and the influence of frictional heat during defibration is also reduced. It can be reduced. The paper used here includes newspaper, cardboard, copy paper, etc.
Any kind of paper is fine. Furthermore, in the present invention, in the step of impregnating the defibrated material with molten resin, the defibrated material is impregnated by hot-pressing a resin sheet, or the defibrated material is arranged in a sheet shape and resin powder is added thereto. It is effective to heat the resin by stirring the defibrated material and the resin at high speed, and melt and impregnate the resin into the defibrated material by increasing the temperature due to frictional heat. In this method, a method such as high-speed stirring in a high-speed fluid mixer is effective, but in this case, the rotation speed is reduced as soon as impregnation is completed, and high-speed stirring in the molten state is not performed. It is better to impregnate the molten resin quickly; if it takes too long, the fibers will become short and the above-mentioned problem will likely occur. The resin used in the present invention may be any thermoplastic resin that is normally used as a molding material, but it is better to use a relatively low melting point resin such as polyolefin resin such as polyethylene or polypropylene, polystyrene, or polyvinyl chloride. The cellulose-based plant fibers are less susceptible to thermal deterioration when impregnated with resin, and exhibit their characteristics as reinforcing materials. Further, in this impregnation step, by adding an additive or a resin as a third component in addition to the fiber and resin to improve the adhesion between the fiber and the resin, even better mechanical properties can be exhibited. For example, when a defibrated material and a polyolefin resin are stirred at high speed and the temperature rises due to frictional heat, the polyolefin resin is melted and impregnated into the defibrated material. When polyolefin is added and the fibers and polyolefin resin are stirred at high speed, the modified polyolefin resin with a low melting point is first melted and impregnated into the fibers, improving the wettability of the fibers, and then the polyolefin resin is melted and impregnated. The properties of the resulting fibrous material are better. It is also possible to add additives depending on the purpose. The resin as the third component is, for example,
Those disclosed in Japanese Patent Publication No. 53-1319 and Japanese Patent Publication No. 45-36421 can be used. In the present invention, in the step of cooling the resin at the same time as the completion of impregnation, it may be allowed to cool by leaving it at room temperature, but it is effective to transfer the impregnated material to a cooling tank. The stirred and impregnated material can be granulated into particles of appropriate size at the same time as cooling by lowering the rotation speed and discharging it into a cooling mixer such as a cooling mixer to cool it. This can also be used as a molding material as it is. [Effects of the Invention] The resin composite composition using paper according to the present invention can be produced by separating the paper fibrillation process and the impregnation process during the production of the paper resin composite composition, and producing vegetable fibers mainly composed of cellulose. damage and thermal deterioration can be controlled. Since the resin is melted and impregnated into the defibrated material by the frictional heat generated by high-speed stirring between the defibrated material and the resin, both steps of dissolving the resin and impregnating the resin can be performed simultaneously. In the step of resin impregnation, mechanical properties can be further improved by adding a third component to the defibrated material and the resin to improve the adhesion between the fibers and the resin. [Example] Examples according to the present invention and examples according to the conventional method as comparative examples thereof are shown below, and the mechanical properties of test pieces as molded products are compared. Example 1 30% by weight of newspaper cut into small pieces with a diameter of about 3 to 6 mm is pulverized in a turbo mill to obtain a defibrated material. 70% by weight of a polypropylene block copolymer having a melt index of 20 is added to this defibrated material, and the mixture is stirred at high speed using a high-speed fluid mixer. At this time, the temperature rise due to frictional heat causes the resin to melt and impregnate the defibrated material. At the same time as the impregnation was completed, the rotation speed was reduced, and the mixture was immediately discharged to a cooling mixer and granulated to obtain a resin composite composition using paper. Example 2 40% by weight of newspaper cut into small pieces with a diameter of about 3 to 6 mm is pulverized in a turbo mill to obtain a defibrated material. 60% by weight of a polypropylene block copolymer having a melt index of 20 is added to this defibrated material, and the mixture is stirred at high speed using a high-speed fluid mixer. In the subsequent steps, the same method as in Example 1 was used to obtain a resin composite composition using paper. Example 3 30% by weight of newspaper is put into a grain mixer as it is without being cut into small pieces, water is added in the same weight as the newspaper, and the mixture is defibrated by stirring at high speed. Thereafter, a resin composite composition using paper was obtained using the same method as in Example 1. Example 4 40% by weight of newspaper is put into a grain mixer as it is without being cut into small pieces, water is added in the same weight as the newspaper, and the mixture is defibrated by stirring at high speed. Thereafter, a resin composite composition using paper was obtained using the same method as in Example 1. Example 5 30% by weight of newspaper cut into small pieces with a diameter of about 3 to 6 mm is placed in a high-speed fluid mixer and defibrated by stirring at high speed. To this defibrated material, 56% by weight of a polypropylene block copolymer with a melt index of 20 was added, and in order to improve the adhesion between the resin and paper fibers, an endo-bicyclo copolymer with a melt index of 15 and an olefin component of 99.8% by weight was added. 14% by weight of a modified polyolefin to which 0.2% by weight of 2,2,1)-5-heptene-2,3-dicarboxylic anhydride has been added is charged and stirred at high speed. At this time, the temperature rise due to frictional heat causes the resin to dissolve and impregnate the defibrated material. At the same time as the impregnation was completed, the rotation speed was reduced, and the mixture was discharged into a cooling mixer and granulated to obtain a resin composite composition using paper. Example 6 30% by weight of newspaper cut into small pieces with a diameter of about 3 to 6 mm was ground in a turbo mill to obtain a defibrated material. After the impregnation step, a high-speed fluid mixer was used in Example 5.
A resin composite composition using paper was obtained using the same ingredients and method. Example 7 40% by weight of newspaper was put into a grain mixer without being cut into small pieces and defibrated by stirring at high speed. After the impregnation step, a resin composite composition using paper was obtained using the same components and method as in Example 5 using a high-speed fluid mixer. Example 8 30% by weight of newspaper was put into a high-speed fluid mixer without being cut into small pieces, and defibrated by stirring at high speed. After the impregnation step, the same ingredients and method as in Example 5 were used to obtain a resin composite composition using paper. Example 9 30% by weight of newspaper cut into small pieces with a diameter of about 3 to 6 mm is put into a high-speed fluid mixer, water is added in the same weight as the newspaper, and the mixture is defibrated by stirring at high speed. After the impregnation step, the same ingredients and method as in Example 5 were used to obtain a resin composite composition using paper. Example 10 30% by weight of newspaper is put into a grain mixer as it is without being cut into small pieces, water is added in the same weight as the newspaper, and the mixture is defibrated by stirring at high speed. After the impregnation step, a resin composite composition using paper was obtained using the same components and method as in Example 5 using a high-speed fluid mixer. Comparative Example 1 30% by weight of newspaper cut into small pieces of about 3 to 6 mm in diameter and 70% by weight of a polypropylene block copolymer with a melt index of 20 are placed in a high-speed fluid mixer and stirred at high speed. The frictional heat generated at this time raises the temperature and melts the resin. The paper is beaten in this resin-dissolved state. Thereafter, it was discharged into a cooling mixer and cooled to obtain a resin composite composition using paper. Comparative Example 2 40% by weight of newspaper cut into small pieces of about 3 to 6 mm in diameter and 60% by weight of a polypropylene block copolymer with a melt index of 20 are placed in a high-speed fluid mixer and stirred at high speed. The frictional heat at this time raises the temperature and melts the resin. The paper is beaten in this resin-like state. Thereafter, it was discharged into a cooling mixer and cooled to obtain a resin composite composition using paper. A test piece was formed using a resin composite composition using paper obtained by the manufacturing method described in the above Examples and Comparative Examples, and the mechanical properties thereof were compared. The results are shown in Table 1. As shown in Table 1, the test pieces using the paper-based resin composite composition according to the present invention exhibit better mechanical properties than those made using the conventional method. Therefore, according to the present invention, the characteristics of paper fibers mainly composed of cellulose can be fully exhibited. Moreover, when a third component was added to improve the adhesion between the fiber and the resin in the impregnation step, the effect could be further enhanced. The method for measuring each physical property is as follows. (1) Tensile strength ASTM D-638 (2) Flexural modulus ASTM D-790 (3) Izot impact strength ASTM D-256 The elongation was conducted in accordance with ASTM D-638, but the crosshead of the tensile test device It was calculated by dividing the amount of movement by the length of the parallel part of the specimen. Furthermore, in the impact strength column of Table 1, "notch" refers to a groove provided in the test piece.

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Claims (1)

[Scope of Claims] 1. A method for producing a resin composite material composition, comprising the steps of defibrating paper, impregnating the defibrated material with molten resin, and cooling after completion of the impregnation. 2. The method for producing a resin composite composition according to claim 1, wherein an appropriate amount of water is added to the defibration step. 3. Claims that the impregnation step includes a configuration in which the defibrated material from the defibrating step and the resin are stirred at high speed and the resin is melted and impregnated into the defibrated material by a temperature rise due to frictional heat between the two. 2. A method for producing a resin composite composition according to item 1. 4. The method for producing a resin composite composition according to claim 3, wherein an appropriate amount of water is added to the defibration step. 5. A patent that includes a configuration in which the impregnation step involves melting the resin and a third component that improves the adhesion between the resin and the fibers of the defibrated product obtained in the defibrating step, and impregnating the defibrated product with the melt. A method for producing a resin composite composition according to claim 1. 6. Manufacturing a resin composite composition according to claim 5, wherein the resin and the third component are melted in the impregnation step by frictional heat caused by high-speed stirring of the resin, the third component, and the defibrated material. Method. 7. The method for producing a resin composite composition according to claim 5 or 6, wherein an appropriate amount of water is added to the defibration step.