JPH0322409B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to the provision of a reinforced resin molded product that has a low coefficient of thermal expansion, less molding or molding distortion, and has excellent abrasion characteristics and bending strength characteristics. It is.

[Prior Art] Conventional methods for strengthening resin molded products include mixing inorganic materials such as glass fibers and lock fibers, but there is a need to provide resin molded products with a more natural feel.ゝ、
For the purpose of keeping molding costs low, various attempts have recently been made to mix wood powder into materials such as polyvinyl chloride, polyethylene, acrylonitrile-butadiene-styrene, and the like.

Mixing the required amount of wood powder into such molding resin increases the strength of the resin molded product, especially the bending strength, approximately twice that of the non-mixed resin molded product, and also reduces distortion during resin molding and after molding. It has a significantly low wear resistance and particularly improved abrasion resistance, and is particularly meaningful in providing an ideal and inexpensive reinforced resin molded product.

[Problem to be solved by the invention] However, despite such excellent properties of the molded product, the inherent properties of the wood flour material mixed in gently reduce the molding properties of the resin, resulting in a relatively expensive product. It is considered a product.

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. In addition, the moldability per unit time is particularly reduced.

This also causes particular wear and tear on the inside surface of the molding machine, reducing the service life of the molding machine, as well as causing excessive pressure on the die or mold surface, causing breakage and wear of the die or damage and wear of the inside surface of the mold. At the same time, the surface roughness of the molded product itself was induced.

In addition, in the conventional case, mixed wood powder generates a large amount of wood acid, acetic acid, etc. during hot molding, and this wood acid induces corrosion of the molding machine cylinder, screw, die, mold inner surface, etc. This significantly reduces the frequency of use of molding machines, molds, etc., and also induces roughening of the surface of the molded product.

[Means for Solving the Problems] The reinforced resin molded product according to the present invention was specially devised in view of the inconveniences in the conventional precedent, and the wood powder to be mixed is mixed with wood chips, etc., and this is prepared in advance. After heat-curing a thermosetting resin, especially a urea resin or melamine resin that generates alkaline gas during thermosetting, it is crushed or polished into powder or chunks to neutralize the wood acid generated. At the same time, we use aggregate that has almost the same frictional resistance inherent in wood flour as that of the molded resin material, and add 15% to 50% of this into the resin material.
This is a molded product made of reinforced resin by mixing an equivalent amount of 50% of the above-mentioned resin, eliminating the disadvantages of the previous examples mentioned above, and providing a molded product with excellent properties such as bending strength at a low price.

[Example] Hereinafter, a typical example of the reinforced resin molded product according to the present invention will be explained in detail. Wood chips or wood flour, etc. are mixed with a thermosetting resin material, and the mixture is heated using a hot pressing method or the like. It is heated and hardened to form plates, blocks, bars, etc., and is first used to neutralize wood acids such as acetic acid produced when wood flour or wood chips are heated. Therefore, the thermosetting resin material used is particularly one that contains aldehydes and generates alkaline gas when heated and hardened, such as urea resin or melamine resin.

The thus neutralized wood chips, wood flour, etc. are the main components of the board, bar, or lump material, which is cut, crushed, or other means into mixed aggregate with an appropriate particle size. Wood chips used as aggregate have a resin material impregnated and hardened in the wood composition, so that the frictional resistance of the crushed surface exhibits a resistance value similar to that of chips made of molded resin material.

As a result, during molding, extrusion or injection pressure is not required more than necessary, and it is possible to provide molded products of almost the same size using a normal molding machine. This eliminates the risk of wear and tear on the molding machine cylinder, screw, die, mold, etc. caused by the generation of internal pressure.

That is, the aggregate provided in the above is neutralized with the thermosetting resin material in the previous pretreatment, and the surface smoothness is guaranteed, and the frictional resistance is reduced. It promises molding properties similar to those of aggregate.

The aggregate thus provided ranges from 15% to 50%,
In particular, about 30% is made up of vinyl chloride, polystyrene,
It is mixed into materials such as ABS resin and molded into reinforced resin molded products using methods such as injection or extrusion.

In addition, the preparation of the aggregate exemplified in the above is intended to create the aggregate specifically, but the abrasive powder generated during the surface polishing of particle boards that are normally produced and commercially available can be used as an example. It was also planned to be used as mixed aggregate, and its molding method and composition are the same as the mixed aggregate in the above case.

The use of such particulate board abrasive powder promises to further reduce the molding cost for the aggregate molding in the case described above. In other words, particle boards made under pressure 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.

The aggregate mentioned above is made from wood chips, wood flour, etc. whose moisture content has been reduced to around 13% through a series of pretreatment processes such as heating, compression, and curing. By mixing a certain amount of aggregate, the generation of water vapor during molding is minimized, and the molded surface is prevented from becoming rough and various air bubbles are prevented from forming.

[Effects of the Invention] The reinforced resin molded product according to the present invention has the above-mentioned characteristic structure, which makes it possible to 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 and after molding.

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 allows for perfect surface treatment with lacquer, paint, etc., and at the same time, the unique color tones of wood can be achieved by mixing 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 conventional wood-like materials made by spraying, molding, or pasting with decorative sheets, there is no hint that it is a synthetic resin material. It was effective.

In addition, the amount of abrasive powder generated by particle board, which is subjected to single-sided or double-sided abrasion of aggregate mixed into resin molded products, is extremely large, and there are many difficulties in disposing of the generated abrasive powder. However, in the case of abrasive powder for particle board, it not only makes effective use of resources, but also promises to reduce the cost of molded products, and can also help with recycling, which has become an issue in recent years. It is.

Claims (1)

[Claims] 1. A thermosetting resin material that generates alkaline gas when cured by heating and wood chips are mixed, and the resulting cured product is crushed or polished to form a molded resin material using crushed powder, lumps, or polished powder 15% during
Reinforced resin molded product made by mixing ~50%.