Coating processes – Direct application of electrical – magnetic – wave – or... – Electrostatic charge – field – or force utilized
Reexamination Certificate
2001-08-27
2004-12-14
Berman, Susan (Department: 1711)
Coating processes
Direct application of electrical, magnetic, wave, or...
Electrostatic charge, field, or force utilized
C427S535000, C427S536000, C427S538000, C427S551000, C427S553000, C427S533000, C433S008000, C522S111000, C522S112000, C522S088000, C522S150000, C522S151000, C522S153000, C522S155000, C522S157000, C522S161000, C522S162000, C522S163000, C522S164000, C522S165000, C522S166000, C525S388000
Reexamination Certificate
active
06830782
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method of modifying the property of a polymeric material. More particularly, the invention relates to a method to improve the properties such as water absorption and adhesion, etc. of a polymeric material without lowering the practical strength of the material.
BACKGROUND ART
Because polyolefins such as polypropylene, polyethylene, etc. have excellent properties of light weight, large strength, good chemical resistance, etc., they are extensively used for films, non-woven fabrics, molded materials for automobile components and members of electrical apparatus, etc. On the other hand, polyolefin materials have a small polarity and a high crystallinity, which are derived from its chemical structure, thus they have a small hydrophilic property and a difficulty in chemical modification. Various surface activation treatments such as ozone treatment, plasma treatment, ultraviolet light irradiation, high voltage electric discharge, corona discharge, etc. have been carried out to improve the hydrophilic property and adhesive property of polyolefin materials. However, even if any method of them is employed to treat a polyolefin material, we cannot obtain an effective result that the treated material absorbs water as much as several times the weight of original material.
Various kinds of treatments have been proposed in order to improve the property of polymeric materials such as polypropylene, etc. For examples, the ozone oxidation treatment was examined to improve the property of metal plating, painting and adhesion (Japanese Laid-Open Patent Publication No. H3-103448 (1991)). However, when only the ozone treatment is employed to improve the property of the material, it needs very strict conditions which cause the lowering of the mechanical strength; this makes a problem that the treatment is not practical. Furthermore, it is impossible to give a large water absorption property to the material only by the ozone treatment.
Furthermore, it was proposed that vinyl monomers containing ester bonds were grafted to non-woven fabrics made of polyolefin and then, the ester bonds were hydrolyzed to form acid groups giving a hydrophilic property and an ion-exchange property (Japanese Laid-Open Patent Publication No. H11-7937 (1999)). However, the grafting of vinyl monomers to polyolefin to give a large hydrophilic property is not easily carried out by the proposed method. Still more, the method needs the hydrolysis treatment after the grafting, which causes a laborious problem.
On the other hand, a method to improve a hydrophilic property of non-woven fabrics made of polyolefin fibers by the treatment with hydrophilic resin in the presence of a persulfate was proposed (Japanese Laid-Open Patent Publication No. H11-67183 (1999)). Although this method gave practically a hydrophilic property to non-woven fabrics, the hydrophilic property is not durable in use. In addition, this method was not applicable for the improvement of hydrophilic property and adhesion property of films and molding materials except non-woven fabrics. For instance, the hydrophilicity given by this method is considerably lost by washing with a hot detergent solution.
It is known that a method to improve a hydrophilic property of non-woven fabrics by coating them with polyvinyl alcohol (Japanese Laid-Open Patent Publication No. H1-248460 (1989)). Although the hydrophilic property of the treated non-woven fabrics is high, its durability is very low because the treatment is only coating. In addition, the coated non-woven fabrics give a disadvantage in that when they are used as battery separators, they shrink and cause short-circuiting in the batteries.
The present inventor proposed a method to improve the surface property, or especially, the dyeability of polymeric materials, which is composed of activation treatment of the surface of polymeric materials, monomer grafting such as acryl amide, etc. on them and Hofmann rearrangement of the amide groups in grafts (Japanese Laid-Open Patent Publication No. H8-109228 (1997)). Although this method is available for improving the hydrophilic property of some polymeric materials, the kind of available polymeric materials is limited.
The present invention provides a method for improving a durable water absorption property, a hydrophilic property and an adhesion, etc. for a polymeric material without lowering the practical strength. The present invention also provides medical/sanitary/cosmetic supplies; disposable diapers, sanitary or other napkins, bandages, gauze and disinfectants and various water-absorption materials for cleaning, cleanser pack, etc., water retention materials useful for agriculture/greening in dry districts, materials for microorganism culture media, synthetic paper, filter media, battery separators with alkali/acid proofing, members of writing materials with an excellent absorption property of water-soluble ink, wiping/cleansing materials, orthodontic brackets, medical materials (artificial organs, artificial joints, medical tubes and the other molded materials with string or plate forms), polymeric materials with improved adhesive property and polymeric materials for composites.
DISCLOSURE OF INVENTION
The present inventor investigated the method for improving the property of polymeric materials such as a water adsorption property, a hydrophilic property, and an adhesion property, etc. and discovered that a combination of a solvent treatment, an activation treatment, a hydrophilic polymer treatment and a monomer grafting is effective for the improvement, and completed the present invention.
A first aspect of the present invention relates to the method for improving polymeric materials by (1) the step of activation-treatment and (2) the step of a hydrophilic polymer-treatment in this order.
A second aspect of the present invention relates to the method to improve polymeric materials by (1) the step of activation-treatment and (2) the step of a hydrophilic polymer-treatment and (3) the step of monomer grafting in this order.
A third aspect of the present invention relates to the method to improve polymeric materials by (1) the step of a solvent-treatment, (2) the step of activation-treatment and (3) the step of a hydrophilic polymer-treatment in this order.
A fourth aspect of the present invention relates to the method to improve polymeric materials by (1) the step of a solvent-treatment, (2) the step of activation-treatment, (3) the step of a hydrophilic polymer treatment and (4) the step of monomer grafting in this order.
The present invention also relates to the products prepared from the polymeric materials improved by the above methods; a water absorption material, a water retention material, a material for microorganism culture media, a synthetic paper, a filter medium, a battery separator, a member of writing materials (members made of polymer used for various kinds of pens with water-soluble ink, felt pens, brush pens, fountain pens and ball-point pens, etc.), a wiping/cleansing cloth, a disposal medical/sanitary/cosmetic supply (a diaper, a sanitary napkin, a bandage, a gauze, the other medical/sanitary supply and various cosmetic supplies for cleaning/cleansing pack), a material improved in adhesion property, an orthodontic bracket, a medical material (an artificial organ, an artificial joint, a medical tube and the other molding material of tube, string or plate), etc.
The present invention will be described in more detail. (Polymeric materials)
Polymeric materials used in the present invention include the polymer material contained in each of a single polymer or a mixture of synthetic or natural polymers, a modified single polymer or polymer mixture, a material prepared by mixing or conjugating the polymers with glass, metal and carbon fiber, etc.
Both thermoplastic polymers and thermosetting polymers are used as synthetic polymers. Various methods for the preparation of these polymers are exemplified, and all polymers prepared by these methods can be used. For example, the following polymers are available
Berman Susan
Scully Scott Murphy & Presser
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