JP2002309096A - Crushed cork particle composition and crushed cork particle molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crushed cork particle composition excellent in processability, and to provide injection molding products of the crushed cork particle composition suitable for daily sundries such as, in the beginning, cores for footwear, parts for industrial products and the like. SOLUTION: This crushed cork particle composition is characterized by comprising crushed cork particle having 0.2-5 mm particle size and 10-100 pts.wt. thermoplastic polymer adhesive per 100 pts.wt. crushed cork particle, and the other objective crushed cork particle composition molded product is provided by injection-molding of the crushed cork particle composition in a forming mold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a crushed cork composition containing crushed cork and a thermoplastic polymer adhesive. Further, the present invention relates to a cork crushed granule composition suitable for daily miscellaneous goods such as a core of footwear and parts for industrial products, and a molded product of a cork crushed granule composition injection-molded into a molding die.

[0002]

2. Description of the Related Art Cork is a natural material obtained from the epidermis of a cork oak, which is a plant, and is composed of a fibrous tissue containing many air bubbles. Cork having such a structure has a small specific gravity of 0.12 to 0.20, is lighter than other wood materials, and is not only excellent in heat insulation, soundproofing, elasticity, abrasion resistance, etc. Because of its high decorativeness, it is widely used for building materials such as flooring materials and wall materials, sealing materials such as cork stoppers, daily miscellaneous goods, and decorative accessories by utilizing its features.
As described above, cork is used for various purposes. However, there is a drawback in that the workability of the cork is inferior to other wood materials in the thickness and strength of cork bark.

[0003] For example, in the manufacture of the core of Japanese dressing sandals, a large cork block is first made, the block is cut into small blocks, and the small blocks are cut into the shape of the sandals core. The process involves handwork and machining, intermingling forty steps.More specifically, the adhesive is evenly dispersed in the crushed cork raw material, and filled into a container that makes a large block of cork, A block making process in which drying is performed over a long period of time while applying pressure so that the volume becomes half. The block is subdivided into the size of the core of the sandals, and one small block is divided in the diagonal direction to form a rough sandstone-shaped block. When each process such as shaving, warping, rounding into the shape of sandals, drilling, etc., is completed, the entire part is polished. Fine work such as pattern pasting, drying, and nailing is also added during these steps, but the core of Japanese dressed sandals is generally made through the above steps. As described above, in the production of a conventional cork molded product, an adhesive is added to the crushed cork granules, and the step of molding the block by heat and pressure requires a long time to cure the adhesive and requires a number of processing steps, There was a problem that the working efficiency was remarkably low and mass production could not be handled.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to an injection molded article of a crushed cork composition excellent in processability and a crushed cork composition suitable for daily miscellaneous goods such as the core of footwear and parts for industrial products. Is provided.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, mixed cork crushed granules having a fixed particle size and a thermoplastic polymer adhesive at various ratios. The present inventors have found that a desired molded product can be easily obtained by injecting into a mold at a high pressure by an injection molding machine and hardening the same, thereby completing the present invention. That is, the present invention provides a crushed cork having a particle diameter of 0.2 to 5 mm and a crushed cork 100
A cork crushed granule composition comprising 10 to 100 parts by weight of a thermoplastic polymer adhesive per part by weight, and a cork crushed granule composition molded article obtained by injection-molding the cork crushed granule composition into a molding die. Hereinafter, a specific manufacturing method will be described.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The cork crushed granules of the present invention are not particularly limited, but crush a thickly grown epidermal portion of a cork oak generally used as a cork material to reduce the particle size from 0.2 mm to 5 mm. It refers to a sized product, and furthermore, crushed chips obtained as a by-product during cork processing, small pieces not suitable for processing, and the like can be used in the same manner.
It is more preferable to use chips and small pieces because they are effective for effective use of resources and reduction of raw material costs. The method of crushing and the method of sizing are not particularly limited, and a commonly used crusher or sieving machine can be used.

The particle size of the crushed cork particles of the present invention is preferably from 0.2 mm to 5 mm, more preferably from 0.5 mm to 5 mm, in order to give fluidity at the time of injection molding and a texture peculiar to cork.
mm to 3 mm, most preferably 1 mm to 3 mm. If the particle size is smaller than 0.2 mm, a texture unique to cork cannot be obtained.

[0008] The thermoplastic polymer adhesive of the present invention refers to a polymer material having plasticity at a certain temperature or higher, and it does not matter whether the origin is synthetic or natural. Examples of the synthetic thermoplastic polymer adhesive include polyolefins such as polyethylene and polypropylene, and polyethylene is preferred in terms of melting point, texture, cost, and the like. Starch, as a biodegradable thermoplastic polymer adhesive derived from natural products
Examples include water-soluble polymer adhesives such as glue and casein, and polylactic acid. In the case of a water-soluble polymer adhesive such as starch, glue, casein, etc., although there is a defect that the molded product has poor water resistance, it has a high biodegradability and is environmentally friendly. On the other hand, polylactic acid has characteristics such as excellent water resistance and strength of the molded product and excellent biodegradability. In the present invention, a thermoplastic polymer adhesive can be appropriately selected and used according to the purpose.

The crushed cork composition of the present invention is not particularly limited as long as it contains 10 to 100 parts by weight of the thermoplastic polymer adhesive per 100 parts by weight of the crushed cork, and if necessary, it may be colored. It does not preclude the inclusion of other excipients within a range that does not impair the pigment or physical properties of the composition. The mixing ratio of the cork crushed granules and the thermoplastic polymer adhesive is to provide the moldability during injection molding and the texture, heat insulation, soundproofing, elasticity, abrasion resistance, etc. unique to cork to the molded product.
Preferably, the thermoplastic polymer adhesive is 10 to 100 parts by weight, more preferably 5 to 100 parts by weight, per 100 parts by weight of cork crushed granules.
0 to 100 parts by weight, more preferably 80 to 100 parts by weight. When the blending ratio of the thermoplastic polymer adhesive is less than 10 parts by weight, the thermoplasticity of the composition is significantly reduced, and molding becomes difficult. On the other hand, when the blending ratio of the thermoplastic polymer adhesive exceeds 100 parts by weight, the obtained molded product does not exhibit cork characteristics, and the object of the present invention cannot be achieved.

In addition, the water contained in cork, which is a constituent of the crushed cork composition of the present invention, becomes steam when heated to 100 ° C. or higher at the time of injection molding, and forms a cavity inside the composition to form a molded product. In some cases, it may be adversely affected on the tissue, and it is desirable that the material be dried in advance so that the content is preferably 10% or less, more preferably 3% or less. The drying method may be a commonly used method, for example, 1 hour in an oven.
It may be appropriately selected such as heating to around 00 ° C.

The molded product of the present invention can be easily obtained by injection-molding the above-mentioned cork crushed granule composition into a desired molding die using a general plastic injection molding machine. There is no limitation.

The molding temperature in injection molding is appropriately determined according to the melting point of the thermoplastic polymer adhesive in the composition. In order to prevent coloring and burning of the cork powder due to heat, it is preferably 140 to 220 ° C. Preferably 150 to 190
It is in the range of ° C. The thus obtained molded product of cork crushed granules can be suitably used for a shoe core as it is by using a molding die having the shape of a shoe core such as Japanese sandals. Furthermore, by changing the shape of the molding die, a cork molded product for use in daily goods and industrial product parts can be easily obtained. The molded article may be used after polishing or coloring the surface according to the purpose. Examples are shown below, but the present invention is not limited by these examples.

[0013]

Example 1 Cork crushed particles having a particle size of 1 mm to 2 mm and 2 mm to 3 mm were mixed in equal amounts, and 5 Kg of the cork crushed particles and 5 kg of polypropylene resin powder were uniformly mixed to obtain a crushed cork composition of the present invention. 10 kg of the product were obtained. Example 2 The crushed cork composition of Example 1 was dried with hot air at 140 ° C. for 5 hours. Next, the above-described cork crushed granule composition is put into a hopper of an injection molding machine, and is heated by an external heating cylinder with a heating cylinder so that the product temperature becomes 150 ° C. while being transferred in the direction of the molding die by rotation of a helical cylinder. While imparting fluidity to the composition, the composition was injected at a high pressure into a molding die for obtaining the shape of the core of the shoe, to obtain a molded cork granule having the shape of the shoe core of the present invention. The molded product not only has a preferable texture peculiar to cork, but also has properties such as durability, a flexural strength of 3.59 kg / mm ² and an elastic limit point of 26.
0 kg / mm ² , which was higher than the conventional value.

[0014]

Industrial Applicability The crushed cork composition of the present invention not only facilitates the molding of footwear and other parts for daily miscellaneous goods and industrial products, but also can significantly improve the production process, It can provide a highly degradable molded product, and greatly contributes to the promotion of the cork industry.

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Claims (5)

[Claims] 1. A cork crushed particle composition comprising: a cork crushed particle having a particle diameter of 0.2 to 5 mm; and 10 to 100 parts by weight of a thermoplastic polymer adhesive per 100 parts by weight of the cork crushed particle. 2. The cork crushing composition according to claim 1, wherein the thermoplastic polymer adhesive is polypropylene. 3. The method according to claim 1, wherein the thermoplastic polymer adhesive is a biodegradable thermoplastic polymer derived from a natural product.
A crushed cork composition as described in the above. 4. A molded article of a crushed cork composition obtained by injection-molding the crushed cork composition according to claim 1 into a molding die. 5. The molding die is a footwear die.
A molded article of the crushed cork composition according to the above.