JPH04316684A - Leather-like formed article - Google Patents

Abstract

PURPOSE:To obtain the subject formed article having high hygroscopicity similar to natural leather by mixing spherical sericin having particle diameter smaller than a specific level into a synthetic rubber or a synthetic resin and heat- forming the mixture. CONSTITUTION:Sericin having spherical form of <=20mum in diameter is mixed into a synthetic rubber (e.g. butadiene or olefin rubber) or a thermoplastic resin (e.g. vinyl acetate resin) and the obtained compound is heat-formed by conventional method to obtain an excellent leather-like formed article resembling natural leather in the surface nature and having high hygroscopicity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like molded article having a surface condition similar to that of natural leather and having high hygroscopicity.

0002

BACKGROUND OF THE INVENTION Conventional synthetic resin molded products exhibit the surface feel of the resin used, and have no hygroscopicity or resistance, resulting in poor feel and texture. Therefore, various improvements have been made to improve these and bring the appearance, texture, feel, moisture absorption, etc. closer to those of natural leather. As one of the methods, a leather-like synthetic resin molded product, which is a synthetic resin mixed with leather powder, gelatin powder, etc., has been proposed.

0003

[Problem to be solved by the invention] However, when leather powder is mixed with synthetic resin, the particle size of the leather powder is large, and the resulting resin molded product has a low slipperiness in the mixed material and the resin fluidity is poor, making it difficult to extrude. The resistance becomes large and smooth extrusion is not possible. As a result, molding distortion is likely to occur due to pulsation during extrusion, and furthermore, it takes time and effort to uniformly knead the resin and powder.

Furthermore, when gelatin is used, gelatin powder is obtained by pulverization even if the particle size is minute, so agglomeration tends to occur, which causes the powder to be unevenly distributed within the resin, resulting in molding distortion and molded product strength. This was the cause of the unevenness of the parts.

Furthermore, gelatin powder is complicated to manufacture; first, it takes two to three months to remove impurities other than gelatin, such as lipids, from bones and skins of cows and pigs, and then gelatin is extracted. The process involves concentrating and drying the gelatin solution through various treatments, and then pulverizing it to form a fine powder, which poses a problem in that the manufacturing process is complex and time-consuming.

The object of the present invention is to solve the above-mentioned problems of the prior art, and in particular to provide a leather-like molded article having excellent properties that can be obtained using easily available materials.

[0007]

[Means for Solving the Problems] The leather-like molded article of the present invention is obtained by mixing spherical sericin with a particle size of 20 μm or less into a synthetic rubber or synthetic resin and heat-molding the mixture.

First, specific examples of synthetic rubber or resin used as a base material include butadiene-based synthetic rubber, olefin-based synthetic rubber, polysulfide rubber, fluororubber, chlorosulfonated polyethylene, silicone rubber, chlorinated rubber, etc. There are rubber elastic materials and thermoplastic resins such as vinyl chloride, vinyl acetate, ABS, polycarbonate, polyethylene, polystyrene, polyurethane, and polyacrylic ester.

[0009] The sericin mixed into such a base material has a particle size of 2
Spherical powder of 0μm or less, especially maximum particle size of 10μm
The average particle size below is preferably about 5 μm. These sericins are usually obtained from silk scouring liquid and have an average molecular weight of 600.
It has a value of 0 to 40,000.

[0010] The amount of sericin mixed into the base material is preferably 5 to 70% by weight of the entire composition; if it is too small, the effect of sericin mixing will not be sufficiently obtained, and if it is too large, the mechanical properties such as strength of the molded product will be affected. decreases.

[0011] If necessary, well-known plasticizers, stabilizers, fillers, lubricants, pigments or paints, blowing agents, mold release agents, etc. are added to the molding composition.

[0012] Sericin and the above-mentioned optional components are added to synthetic rubber or resin to form a compound, which is then molded by calender roll treatment, extrusion, injection, or other known heat molding means.

[0013] In this way, a molded article is obtained in which sericin is exposed on the surface of the molded article.

[0014] If the amount of sericin exposed on the surface of the obtained molded product is small, it is preferable to remove the surface by appropriate means such as sanding, shot plast, or slicing with a cutter.

[0015]Furthermore, by laminating the film or sheet-like molded product with a woven fabric or non-woven fabric as a reinforcing agent, its tear strength can be increased or distortion can be prevented.

As shown in FIG. 1, the molded product thus obtained is such that the micro spherical particles of sericin exposed on the surface of the molded product directly absorb water and swell, and the absorbed water is transferred into the molded product. It has the function of sequentially feeding deep into the molded object through evenly scattered sericin particles, which prevents a sticky feeling upon contact and makes the resistance similar to that of human skin. Moreover, since these particles contain a predetermined amount of water and are in a swollen state, the static electricity inherent in the synthetic rubber or resin is prevented, and unpleasant static electricity discharge does not occur.

[0017] Since spherical sericin with a particle size of 20 μm or less is used, its lubricity allows it to be easily and uniformly mixed into synthetic rubber and resin, making molding easy. It is also possible to suppress variations in strength.

The molded leather-like molded product has a soft feel due to its viscoelasticity, and has improved moisture absorption, prevention of dust adhesion due to static electricity, good coloring and surface coating treatment, ease of adhesive processing, anti-vibration effect, etc. effect can be obtained.

[0019] As a secondary effect, proteins that were discarded during the silk scouring process can be used effectively, and sericin can be separated and recovered, eliminating a very large burden on equipment and operating costs for wastewater treatment of these proteins. It can be greatly reduced by using it.

Due to the characteristics described above, the molded product of the present invention can be used for various purposes, such as use in areas where static electricity is likely to be generated, or in various electrical equipment where static electricity should not be generated. Effective in use.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a leather-like molded article in one embodiment of the present invention.

FIG. 2 is a cross-sectional view of a leather-like molded product mixed with gelatin.

FIG. 3 is a cross-sectional view of a leather-like molded product in which leather powder is mixed.

[Explanation of symbols]

1 Resin 2 Sericin 3 Gelatin 4 Leather powder

Claims (1)

[Claims] 1. A leather-like molded product obtained by mixing spherical sericin with a particle size of 20 μm or less into synthetic rubber or synthetic resin and heat molding the mixture.