| 摘要 |
<p>An abrasive sheet uses as its backing a unified paper sheet comprising a compressed paper web on whose surfaces have been simultaneously applied a compressive force parallel to the faces of the web and a pressure perpendicular to these faces, the web having compressively distored fibres between its surfaces and having incorporated in it a fibre-bonding extensible material. Such a sheet has a binder layer firmly adhered to one side, and to a layer of abrasive grits embedded in it. In an example, paper is impregnated with a latex of a copolymer of acrylonitrile and butadiene, tetrasodium ethylenediamine-tetraacetate and red pigments, and compacted. One side is then coated with polyvinyl chloride plasticized with a copolymer of butadiene and acrylonitrile, and then a binder coat of phenolformaldehyde resin to which granules of sand are applied. A conventional sand size is applied after the binder coat has dried.ALSO:Compositions used to bond a stretchable paper (see Division D2) comprise: (Example 1) an aqueous emulsion comprising butadieneacrylonitrile copolymer (72 : 28), butadienestyrene copolymer (50 : 50), butadiene-styrene copolymer (10 : 90), phenol-formaldehyde resin, tetrasodium salt of ethylenediamine-tetracetic acid and antioxidant; (Example V) a similar composition but without the high-styrene copolymer and the antioxidant; and (Example VIII) acrylonitrile-butadiene copolymer, tetrasodium ethylenediaminetetracetate and red pigments. This paper may be coated with a pressure-sensitive adhesive. In Example II, a paper impregnated as in Example I is back-sized with a composition comprising vinyl chloride-acetate copolymer, polyester plasticizer, epoxy resin, titanium dioxide, sorbitan monostearate, toluene diisocyanate, triethylamine and toluene, and then coated on the other side with an adhesive composition comprising polyisoprene, butadiene-styrene copolymer, diethylene glycol ester of dehydroabietic acid, p-octylphenol-formaldehyde, zinc oxide, 2,5-ditertamyl-hydroquinone, tetrasodium salt of ethylene-diaminetetraacetic acid and 2,6-ditertbutyl-p-cresol. In another Example (V) the adhesive composition comprises polyisoprene, butadiene-styrene copolymer (77 : 23), thermoplastic terpene tackifier, rosin-modified maleic ester, aluminium hydroxide, 2,5 - ditert - amylhydroquinone, 2,6-ditertbutyl-paracresol and toluene diisocyanate.ALSO:Four improvements in or modifications of the parent Specification are described and claimed. In the first, the process and product are modified in that the amount of fibre-bonding material is less than 30% but not less than 10% of the paper sheet. Bonding compositions used in the examples are: (Example I) an aqueous emulsion comprising butadiene-acrylonitrile copolymer (72:28), butadiene-styrene copolymer (50:50), butadiene-styrene copolymer (10:90), phenol-formaldehyde resin, tetrasodium salt of ethylenediamine-tetraacetic acid and antioxidant; (Example V) a similar composition but without the high-styrene copolymer and the antioxidant; and (Example VIII) acrylonitrile-butadiene copolymer, tetrasodium ethylenediamine-tetraacetate and red pigments. Other bonding materials referred to are: natural rubber; diene polymers such as those of butadiene, isoprene or chloroprene; copolymers of these with styrene, acrylonitrile, acrylamide, or acrylic or methacrylic acid or their esters; isobutylene polymers or copolymers; alkyl acrylate polymers or copolymers; polyvinyl ethers; and glue-glycerine. This paper may be coated with a pressure-sensitive adhesive as in the parent case. In Example II, a paper impregnated as in Example I is backsized with a composition comprising vinyl chloride-acetate copolymer, polyester plasticizer, epoxy resin, titanium dioxide, sorbitan monostearate, toluene diisocyanate, triethylamine and toluene, and then coated on the other side with an adhesive composition comprising polyisoprene, butadiene-styrene copolymer, diethylene glycol ester of dehydroabietic acid, p-octylphenol-formaldehyde, zinc oxide, 2,5-ditertamyl-hydroquinone, tetrasodium salt of ethylenediamine-tetraacetic acid and 2,6-ditertbutyl-p-cresol. In another example (V) the adhesive composition comprises polyisoprene, butadiene-styrene copolymer (77:23), thermoplastic terpene tackifier, rosin-modified maleic ester, aluminium hydroxide, 2,5-ditertamylhydroquinone, 2,6-diterbutyl-paracresol and toluene diisocyanate. In the second modification the bonding material is a polymer or copolymer having a modulus of elasticity greater than 107 dynes/cm.2 and in the transition range of viscoelastic behaviour, and is used in amounts less than 30% but not less than 10% of the paper sheet. Suitable binders are: unplasticized polymers and copolymers of vinyl acetate, copolymers of butadiene and styrene with a high styrene content, polymethacrylate esters, polyvinyl alcohol, polyvinylchloride, polyvinylidene chloride, polyvinyl acetals, polyurethanes, polyesters; and elastomers of low modulus of elasticity compounded with large amounts of phenol-formaldehyde resins. Suitable elastomers are polymers and copolymers of chloroprene, isoprene, butadiene-styrene, butadiene-acrylonitrile, or alkyl acrylate esters. The strength and modulus of elasticity of the impregnant may be increased by polyisocyanates or blocked polyisocyanates. This paper too may be coated with pressure-sensitive adhesive. In the third modification, an artificial leather comprises the paper of the parent Specification or of the first modification coated with a flexible polymeric film-forming material and having a piping factor of at least 100. This piping factor is the thickness of the specimen measured in mils divided by the diameter in inches of the smallest mandrel around which the sheet may be bent without causing measurable piping. The layer of flexible polymeric film-former may be embossed to simulate leather. A suitable film-former is nitrocellulose. The fourth modification relates to an abrasive paper (see Division C4).</p> |
