JPH04232704A - Method for regeneration and use of resin composite material - Google Patents

Abstract

PURPOSE:To prepare a stable product in good yield by using only the necessary material, in a flash at the time of the reutilization of the flash generated when a composite material using two or more kinds of resins or a resin and other material incapable of being uniformly melted and mixed is formed into a hollow product. CONSTITUTION:A flash is ground into a proper particle size by a grinder 1 to be introduced into a solution properly adjusted in density and the ground product is separated at every densities. As the grinder 1, for example, one grinding the flash charged from an upper hopper and capable of obtaining a desired grinding particle size by changing the mesh size of a lower grating may be used. Subsequently, when the suspended matter in the solution is regenerated and used, the suspended matter overflowing a weir 2a along with the solution is separated by a filter 3 and further dried by a dryer 4 to become a regenerated resin. When the matter settled in the solution is regenerated and used, the settled matter is taken out of a drain 2b to be separated from the solution and dried to be used. By this method, the effect due to a material of a different kind can be eliminated.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for recycling and using resin composite materials, and more specifically to hollow molded products of composite materials using multiple types of resins or resins and other materials that cannot be melted and mixed uniformly, or during blow molding. This invention relates to a method for efficiently recycling and using generated burrs.

0002

BACKGROUND OF THE INVENTION Conventionally, in the molding of resin products, non-standard products and molding burrs have been reused as raw materials in order to increase the yield of resin. Among these, in the case of products using resin composite materials, for example, systems in which polyolefin is blended with glass fiber, etc., systems in which highly crystalline plastic and polyolefin are blended, or systems laminated in layers with metal foil, etc., different materials Since it is dispersed in a sea-island structure or a laminated structure in the product or burr, if it is reused as is, the strength of the product may decrease.

[0003] In order to avoid such a situation, conventionally,
When reusing burrs, etc., we take measures to reduce the effects of using different materials by adding additives, avoiding the uneven distribution of different materials, and applying physical or chemical treatments such as dispersing them as highly as possible. was.

0004

[Problems to be Solved by the Invention] However, when these methods are used, for example, when physical dispersion is used, the basic physical properties of the recycled material itself may deteriorate due to heat, shearing force, etc. For example, in methods of adding chemical additives, it is often observed that the physical properties of the material itself change due to the additive. Further, these changes may not be constant, and there is a drawback that the conditions for molding the recycled material become unstable or that restrictions must be placed on the molding conditions. In particular, when high shear is applied to finely disperse burrs generated during blow molding or blow molding using the above-mentioned resin composite materials,
Recycling has traditionally been difficult because the resin heats up and deteriorates due to its self-heating.

[0005]

[Means for solving the problem] Therefore, the present inventors
When reusing multiple types of resins or composite materials made of resins and other materials that cannot be melted and mixed uniformly, or when reusing burrs generated during blow molding, the material itself is subjected to almost no physical or chemical history. We conducted extensive research to develop a method for recycling resin composite materials that would allow us to separate and use as many of the necessary materials as possible to produce more stable products. As a result, it has been found that the above object can be achieved by pulverizing the burr and the like into as fine a powder as possible and separating it into various densities in a density adjustment solution. The present invention was completed based on this knowledge.

That is, the present invention provides blow-molded products made of multiple types of resins or composite materials using resins and other materials that cannot be melted and mixed uniformly, or products in which burrs generated during blow-molding are pulverized into as fine a powder as possible. The present invention provides a method for recycling and using a resin composite material, which is characterized in that the material having a desired density is reused as a raw material after being separated into various densities in a density-adjusted solution.

First, the burrs to be recycled in the present invention are generated from composite materials using multiple types of resins that cannot be melted and mixed uniformly. As mentioned above, such composite materials include polyolefins such as polyethylene, polypropylene, polybutene, and polystyrene, as well as various fibers (glass, carbon, metal, etc.).
systems in which these polyolefins are blended with highly crystalline plastics such as polyamides, polyesters, polyacrylonitrile, and saponified ethylene-vinyl acetate alcohol copolymers together with compatibilizers; Examples include systems in which crystalline plastic or metal foil are laminated in layers. In these systems, different materials are dispersed in a sea-island structure (including fillers in addition to alloys) or a laminated structure.

[0008] In the present invention, first, the blow molded product made of the above composite material or the burrs generated during the blow molding are pulverized into as fine a powder as possible. The smaller the size of the crushed fine powder, the better, but when the material has a sea-island structure, it is preferably less than twice the particle size of the island phase, especially less than half the particle size of the island phase, and when the material has a laminated structure, it is preferably less than half the particle size of the island phase. It is preferable that the thickness be at most twice the layer thickness, particularly at most half the layer thickness. This pulverization can be carried out using a conventional pulverizer, and can be carried out either batchwise or continuously.

Next, the pulverized product pulverized to such a size is placed in a solution whose density has been appropriately adjusted, and in the case of a sea-island structure, a part mainly composed of sea phase and a part mainly composed of island phase are separated. In the case of a laminated structure, it is difficult to separate the original materials, such as each laminate with each laminate as the main component. Separate into As the solution whose density is appropriately adjusted, various solutions can be used as long as the solution has a density that allows the pulverized product to be separated into various densities. Use something close to the average value. However, slight modifications can be made depending on the purity of what is to be separated and the importance of recovery. Further, it is desirable to use a solution having a composition that is easy to adjust density and easy to dry, such as a mixed system of water and alcohol. In other words, the relationship between the size of the burr etc. after pulverization and the density of the solution is related to each other and varies depending on the type of raw material, but the finer the recycled product is pulverized, the more the parts mainly containing necessary components and the insoluble components are It is possible to increase the density difference between the main part and the main part, and it is possible to increase the probability of separation of the necessary materials in the solution.

By pulverizing burrs and the like into fine powder in this way and placing them in a solution whose density has been appropriately adjusted, materials with a density greater than the density of the solution will settle, and materials with a lower density will float in the solution. . Note that this operation can be repeated using solutions of different densities as necessary. In addition, the solution and the solid may be separated by a method such as a sedimentation tank that can separate the precipitate, liquid, and suspended matter, regardless of whether it is a batch method or a continuous method.

[0011] Next, the fine powder consisting of the desired material separated in the separation operation using the solution and the solution are separated using a filter or the like, and after drying if necessary, the obtained fine powder is used as a raw material. reuse as This makes it possible to remove unnecessary components that could not be separated in the past and recycle only the necessary components.

FIG. 1 shows an example of an apparatus for carrying out the above-mentioned recycling method. That is, after the above-mentioned burr is crushed to a suitable particle size by a crusher 1, it is placed in a solution 2 whose density has been appropriately adjusted, and the crushed products are separated into various densities as described above. The crusher 1 includes, for example, an upper hopper 1
It is sufficient to use a material that can obtain the desired pulverized particle size by introducing the burr from step a and changing the hole diameter of the perforated plate at the bottom. Next, when reusing the material floating in the solution 2, the floating material that has passed over the weir 2a and the solution are separated by a filter 3, and further dried by a drier 4 to obtain a resin for recycling. In addition, in the case of reusing what settles in the solution 2, it is sufficient to separate what is taken out from the drain 2b from the solution, dry it, and use it.

[0013]

[Examples] The present invention will be explained in more detail below with reference to Examples and Comparative Examples. Example 1 As a resin composite material, a 200 μm barrier material (nylon 66) was laminated between two high-density polyethylene resin plates with a 200 μm thick adhesive made of maleic anhydride modified polyethylene resin, with a thickness of 1 cm. A laminate was used. The burrs generated when molding the hollow molded product of this laminate are crushed to a diameter of approximately 200 μm, and placed in a solution of water and alcohol mixed to a density of 0.98 g/cm3, and the suspended matter is removed and removed from the solution. It was separated and further dried to obtain recycled material. Even when this recycled material was mixed into polyethylene, which is the raw material for the laminate, no decrease in the impact resistance of the manufactured laminate was observed, and even in the -40°C Izod test, the base value (i.e., high-density polyethylene resin own value) 32k
g cm/cm, it was 29 kg cm/cm.

Comparative Example 1 In Example 1, the burr was crushed into fine powder and mixed into polyethylene, which is the raw material for the laminate, without separating it and having an average particle size of 5 mm. As a result, a barrier material having a relatively large particle size as a main component was dispersed in the polyethylene molded article. When this product is subjected to impact, its impact resistance decreases significantly, probably due to stress concentrated on the relatively large barrier material mentioned above, and the base value is 31 kg in the -40°C Izod test.
cm/cm, it was about 1/3.

[0015]

[Effects of the Invention] As explained above, according to the present invention,
In the molding of resin composite material molded products and products using recycled materials made from burrs generated during molding, it becomes possible to recycle them without deteriorating their physical properties. That is,
When reusing multiple types of resin or composite materials using resin and other materials that cannot be melted and mixed uniformly, or when reusing burrs generated during blow molding, you can use only the necessary materials in the burrs, or only the necessary materials in the burrs. Since only the main component is separated and used, it is possible to produce more stable products with high yields with almost no physical or chemical history on the material itself, and the effects of dissimilar materials are almost eliminated. be able to.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an apparatus for carrying out the reuse method of the present invention.

[Explanation of symbols]

1 is the crusher 2 is a solution with appropriately adjusted density 3 is a filter 4 is a dryer

Claims (1)

[Claims] Claim 1: A hollow molded product made of multiple types of resin or a composite material using a resin and other materials that cannot be melted and mixed uniformly, or a product in which burrs generated during blow molding are pulverized into as fine a powder as possible, and the density is adjusted. 1. A method for recycling and using a resin composite material, which comprises separating the materials into various densities in a solution, and then reusing the material with a desired density as a raw material.