Finely cut paper product for use in mixing with resin, ecologically sound resin composition comprising the same, and ecologically sound molded resin article using the composition

Abstract

An object of the invention is to provide a finely cut paper product exhibiting a good workability in the production of a paper-resin composition comprising a mixture of a resin and a natural fiber, and improve the fluidity of an ecologically sound paper-resin composition using the finely cut paper product, so as to improve the moldability thereof when the composition is subjected to a working such as injection molding. An other object thereof is to restrain the generation of yellowing or the generation of an odor.The finely cut paper product for use in mixing with resin according to the invention is obtained by pulverizing neutral or alkaline pigment-free coated paper which comprises 70 to 100% by mass of hardwood bleached chemical pulp, 0 to 20% by mass of softwood bleached chemical pulp and 0 to 20% by mass of an inorganic filler, and has an ISO brightness of 70% or more. The ecologically sound paper-resin composition comprising it comprises 50% or more by mass of the above-mentioned finely cut paper product for use in mixing with resin, wherein the balance is made mainly of a synthetic resin, or wherein the main component is made of the above-mentioned finely cut paper product for use in mixing with resin and a biodegradable resin.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This is a U.S. national phase application under 35 U.S.C. §371 of International Patent Application No. PCT / JP2005 / 016129, filed Sep. 2, 2005 and claims the benefit of Japanese Application No. 2005-083994, filed Mar. 23, 2005. The International Application was published in Japanese on Sep. 28, 2006 as International Publication No. WO 2006 / 100793 under PCT Article 21(2). The contents of the above applications are incorporated herein in their entirety.TECHNICAL FIELD[0002]The present invention relates to a finely cut paper product suitable when a paper-resin composition comprising a mixture of a resin and a natural fiber is produced, and an ecologically sound paper-resin composition using the finely cut paper product. More specifically, this finely cut paper product is a product having an improved workability when the product is compounded into a resin. The paper-resin composition, into which the finely cut paper product is incorporated, is ...

AI Technical Summary

Benefits of technology

[0028]The paper in use is preferably paper comprising 70 to 100% by mass of hardwood bleached chemical pulp, 0 to 20% by mass of softwood bleached chemical pulp and 0 to 20% by mass of an inorganic filler. The paper may contain additives such as a paper strength additive, a sizing agent, a retention aid, and a drainage aids to such an extent that the advantageous effects of the invention are not hindered. The paper may be surface-treated with various starches, a surface sizing agent, or the like by means of a size press, a gate roll or some other device.

[0029]The brightness of the paper in used needs to be an ISO brightness of 70% or more. If the brightness is lower than 70%, yellowing based on water is caused. The ISO brightness is more preferably 75% or more. As the brightness is higher, a more preferred result is obtained. If the brightness of the paper in used itself is low, it is impossible to avoid a problem of yellowing based on water even if a manner for raising the brightness, such as addition of a highly white filler, is performed in a subsequent production of a paper-resin composition.

[0030]The paper in used is preferably neutral or alkaline pigment-free coated paper. If the paper is acidic, at the time of molding the paper-resin composition, a bad effect, such as corrosion of the mold, may be produced onto the molding. If pigment coated paper is used, synthetic binders, in particular, various latexes used in its coated layer cause the generation of a bad odor or a harmful gas when the paper is heated.

[0031]The apparent bulk specific gravity of the finely cut paper product obtained by pulverizing the above-specified paper is preferably 0.1 or more. When the above-mentioned paper is used, a finely cut paper product having an apparent bulk specific gravity of 0.1 can be obtained with relative ease by controlling conditions for the pulverization. If the apparent bulk specific gravity is less than 0.1, the workability may lower remarkably when the finely cut paper product is compounded into a resin.

[0032]The finely cut paper product is kneaded into one or more out of various resins, whereby the product is turned into a paper-resin composition. When the proportion of the finely cut paper product is set to 50% or more by mass, an ecologically sound paper-resin composition is obtained. When a biodegradable resin is used as the resin, an ecologically sound paper-resin composition is obtained.

[0033]Examples of the synthetic resin used in the invention include general-use resins such as polyethylene resin, polypropylene resin, polystyrene resin, acrylonitrile / butadiene / styrene resin, acrylonitrile / styrene resin, urethane resin, polyester resin, polycarbonate resin, and modified resins thereof. These synthetic resins may be newly-synthesized products, or pulverized products or recycled products of used molded products, and may each be a single product or a mixture.

Problems solved by technology

Thus, a bad effect given onto the lifespan of the blade of any pulverizer is small.