JPS6367489B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) This invention provides a reinforced resin molded product that has a low expansion coefficient, less distortion during or after molding, and has excellent wear and bending strength properties. It is related.

(Prior art) Conventional methods for strengthening resin molded products include mixing inorganic materials such as glass fibers and lock fibers, but in order to give resin molded products a more natural feel, In recent years, wood powder or similar cellulosic substances have been mixed into materials such as polyvinyl chloride, polyethylene, acrylonitrile-butadiene-styrene, etc., in order to maintain reasonable molding costs.

(Problem to be Solved by the Invention) Mixing the required amount of wood powder into such a molding resin increases the strength of the resin molded product, especially the bending strength, approximately twice that of a resin molded product without the mixture, and , which significantly lowers the strain rate during resin molding and after molding, and has particularly improved wear resistance, and is particularly meaningful in providing ideal and inexpensive reinforced resin molded products, Despite the excellent properties of the molded product, the inherent properties of the wood flour material contained in the product significantly diminished the molding properties of the resin, resulting in a relatively high price.

That is, when wood powder is mixed in, the mixed wood powder itself extremely inhibits the fluidity of the molded resin material, and also significantly increases the frictional resistance against the inner wall surface of the molding machine cylinder or the sliding surface of the screw, etc. This requires a particularly low formability per unit time.

This also causes particular wear and tear on the inside of the molding machine, reducing the service life of the molding machine, as well as creating unnecessarily high internal pressure on the die or mold surface, causing breakage and wear of the die or damage and wear of the inside of the mold. At the same time, this caused surface roughness of the molded product itself.

In addition, in the prior art, mixed wood powder generates a large amount of wood acid, especially acetic acid, etc. during heat molding, and this wood acid significantly reduces the usage frequency of molding machine cylinders, screws, dies, mold machines, molds, etc. This also caused roughness on the surface of the molded product.

In addition, in the conventional method, a large amount of steam is induced by the mixed wood powder, etc., which adheres to the mold surface, causing problems of surface roughness of the molded product and deterioration of the strength of the molded product.

Furthermore, in such conventional methods, the mixed wood powder and the resin material did not become completely integrated, creating voids, air bubbles, etc. around the mixed wood powder, which significantly reduced the strength of the molded product. It is.

(Means for Solving the Problems) The reinforced resin molded product according to the present invention has been specially devised in view of the inconveniences in the prior art, and the reinforced resin molded product according to the present invention has Wood chips or similar cellulose materials are heated in advance with a thermosetting resin adhesive to harden the adhesive, and then this is cut or crushed into powder or chunks to volatilize the generated wood acid. At the same time, it brings the frictional resistance inherent in wood acid almost to that of the molding resin material itself, eliminates the generation of water vapor gas during molding, eliminates the disadvantages of the previous precedents mentioned above, and has excellent properties such as bending strength. This product provides molded products at low prices.

(Example) Hereinafter, a typical example of the reinforced resin molded product according to the present invention will be described in detail. and as an adhesive material 5~
Knead 15% by weight, heat and press at a temperature of 100 to 110°C for about 5 to 20 minutes using a hot press method, etc. to form a board, lump, stick, etc. First, as wood flour or wood chips are heated, It is produced by gasifying wood acids such as acetic acid and evaporating them.

The wood chips, rods, or lumps from which the wood acid has been removed are made from cellulose materials such as wood flour, and are simultaneously dried to a moisture content of 1 to 5% by the hot pressing process. It is made into neutral and extremely dry aggregate by cutting, crushing or other means to obtain mixed aggregate with an appropriate particle size.

Since the wood chips in such crushed aggregate are impregnated and hardened with a resin material in the wood composition, the frictional resistance of the crushed surface exhibits a resistance value similar to that of chips made of molded resin material. be.

This makes it possible to provide molded products of almost the same size using a normal molding machine without requiring excessive extrusion or injection pressure during molding. This eliminates the risk of wear and tear on the molding machine cylinder, screw, die, or mold caused by the generation of internal pressure.

That is, the aggregate provided in the above is heat-cured with a thermosetting resin material in the previous pretreatment to remove the wood acid in the wood powder in advance, and at the same time removes the moisture contained in the wood powder. It reduces moisture content to about 5%, suppresses moisture absorption after formation, and at the same time promises smooth surfaces and reduces frictional resistance, promising molding properties similar to those of general aggregates. be.

The aggregate thus provided is in the range of 3 to 50%, especially about 30% is made of vinyl chloride, polystyrene, ABS.
It is mixed into thermoplastic resin materials such as resins and molded by injection or extrusion, and compared to conventional wood flour, it blends well with the material and can produce molded products with the desired strength. It is something that was given.

In addition, when molding lightweight materials or moldings that require particular thickness, azodicarbonamide, azobisformamide, azobisisobutyronitrile, barium azobisformate, NN' dinitroso, NN' dimethyl terephthalate may be added to the thermoplastic resin material. It is planned to mix an appropriate foaming agent such as amide in accordance with the desired foaming mode.

In addition, the preparation of the aggregate exemplified in the above is based on the purpose of making the aggregate specifically, but the abrasive powder generated during the surface polishing of normally produced and commercially available particle boards can be used as an example. Naturally, it was planned to be used as mixed aggregate, and the molding method and composition were the same as the mixed aggregate in the above example.

The use of such particle board abrasive powder promises to further reduce the molding cost for the aggregate molding in the above case. That is, particle boards that are pressure-formed using a hot press are usually subjected to single-sided or double-sided polishing, and the amount of abrasive powder generated is extremely large, and there are many difficulties in disposing of the generated abrasive powder. It is something.

The use of particleboard abrasive powder is
In this dual sense, the cost reduction of molded products has been beneficial.

In addition, the aggregate mentioned above undergoes a series of pretreatment processes such as heating, pressing, and curing of cellulosic materials such as wood chips and wood powder to reduce the moisture content to 1 to 5%.
By mixing aggregate with such a low moisture content, we have minimized the generation of water vapor during molding, preventing roughening of the molded surface and also preventing the internal pressure of various bubbles. It is something.

(Effects of the Invention) The reinforced resin molded product according to the present invention has the above-mentioned characteristic structure and can provide a molded product having the above characteristics using the same molding method as in ordinary resin molding. In particular, it is possible to provide a good molded product with a low coefficient of thermal expansion and with little distortion due to changes in composition during molding and in a molding machine.

In addition, it has high bending strength as a mechanical property, and of course has sufficient hardness, and has significantly improved surface abrasion characteristics.

Furthermore, the inclusion of wood-based materials makes it possible to process them using ordinary woodworking machines and tools, and also makes it possible to perfect the surface treatment with lacquer, paint, etc., and at the same time, the wood-based mixture allows for the unique color tones of wood. , which promises a tactile feel in molded products.

In particular, as a woodworking material, the entire cut surface exhibits wood-like characteristics, and unlike previous wood-like materials such as open-holes, molding, or pasting of decorative sheets, the effect is such that no one will notice that it is a synthetic resin material. It has the following.

Claims (1)

[Claims] 1. A thermosetting resin material is added to wood chips or similar cellulosic material, heat-pressed and cured to remove wood acid and water content, and the cured wood material is cut or crushed to form powder or lumps. A reinforced resin molded product characterized in that the aggregate is mixed into a thermoplastic resin material equivalent to 3 to 50% by weight and molded.