Abstract:
An abrasive sheet is made from paper or cloth impregnated with a polyurethane which is chemically bonded to the cellulose of the sheet material (see Divisions D1 and D2). In Example VII, kraft paper is impregnated with the polyurethane and then coated on one side with a butadiene-acrylonitrile latex. It is then coated on the same side with a conventional alkyd varnish and silicon carbide applied. It is finally coated with a conventional alkyd resin. In Example VIII, jeans-cloth is impregnated with the polyurethane and then coated successively with a phenol-formaldehyde make coat, aluminium oxide and a phenol-formaldehyde size.ALSO:Compositions for impregnating paper or cloth to form a polyurethane in situ and to bond it chemically to the cellulose of the sheet material comprise a secondary hydroxyl-terminated polyether polyol and a polyisocyanate. A catalyst for the reaction may be included in the composition or may be incorporated into the sheet before the composition is applied. In the examples: (I) the composition comprises polypropylene glycol, a secondary hydroxyl-terminated triol formed by reacting 1,2,6-hexanetriol with propylene oxide, toluene - 2,4 - diisocyanate, xylene, a polyallyl - polyphenol antioxidant and lead isooctoate; (II) the composition omits the triol but otherwise comprises the same ingredients as in Example (I); (III) the composition comprises a polypropylene glycol, a poly-propylene ether triol and toluene-2,4-diisocyanate, but no solvent or catalyst, paper is first impregnated with a solution of lead octoate, and then with the composition; (IV) the composition comprises polypropylene glycol, polypropylene ether triol, xylene, toluene-2,4-diisocyanate, calcined clay, phenyl mercuric acetate and lead octoate; (V) the composition comprises a polyether triol, toluene-2,4-diisocyanate, xylene and bismuth naphthenate; (VI) the composition comprises a polypropylene glycol, an ethyl acetate solution of the product of reaction of one mole of trimethylol-propane and three moles of toluene diisocyanate, xylene and lead octoate; (VII) the composition comprises a blend of two poly-propylene glycols of different molecular weight, three polyether triols of different molecular weight, toluene-2,4-diisocyanate, TiO2, green pigment, carbon black, xylene and lead octoate; and (VIII) the composition comprises a polyether triol, xylene, toluene-2,4-diisocyanate, and lead octoate.ALSO:A pressure sensitive adhesive tape is made from paper impregnated with a polyurethane which is chemically bonded to the cellulose of the sheet material (see Division D2). In an example, a creped kraft paper is impregnated with the polyurethane and then coated on one side with a butyurea-aldehyde, and on the other with a neoprenephenolic resin containing magnesium and zinc oxide as curing agents. The second side is then again coated with a conventional rubber-resin adhesive.ALSO:Fibrous cellulosic sheet material is impregnated with a polyurethane which is chemically bonded to the cellulose of the sheet material, and is formed by reaction between the hydroxyl groups of the cellulose and of a secondary hydroxyl-terminated polyether polyol with a polyisocyanate sufficient to provide at least one NCO group for each OH group of the polyether. The cellulosic sheet may be paper, e.g. creped kraft, or jeans-cloth. The impregnation may be carried out using a liquid composition containing the secondary hydroxyl-terminated polyol, the polyisocyanate and a catalyst for the reaction, e.g. lead iso-octoate or bismuth naphthamate. Alternatively the sheet may be impregnated first with a solution of the catalyst, dried and p then impregnated with the polyol and polyisocyanate. The polyol and the polyisocyanate may each be bifunctional, e.g. polypropylene glycol and toluene-2,4-diisocyanate, or trifunctional, or contain more than three functional groups. Several examples are given. The impregnating composition may contain a filled e.g. clay, and by suitable choice of filler, the product may be made transparent, e.g. for tracing paper, or opaque. The product may be coated with pressure-sensitive adhesive and used as a pressure-sensitive adhesive tape, or may be coated with adhesive and abrasive to make an abrasive sheet.
Abstract:
A vinyl ester of an organic acid such as acetic or propionic acid is copolymerized with a neutral ester of an ethylene a b -dicarboxylic acid with a saturated alcohol R111-A-C(R1.R11)-CHR.OH, where R, R1 and R11 are hydrogen or saturated alkyl groups, A is oxygen, methylene or an alkyl methylene and R111 is a saturated alkyl or alkoxy-alkyl group. Esters specified are 2-ethylbutyl-, 2-butoxyethyl-, 2-ethoxyethyl- and butyl maleates. In aqueous emulsion alkyl sulphates, aryl sulphonic acid salts, amine salts and soaps, methyl cellulose, gelatine, methyl starch, polyvinyl alcohol, sodium alginate, ammonium or potassium persulphate, p hydrogen peroxide or sodium perborate may be used. Small amounts of acrylic acid, or cross-linking agents such as allyl, methallyl, and crotyl esters of succinic, maleic, fumaric, adipic, sebacic, phthalic, acrylic, methacrylic, crotonic and cinnamic acids, glycol diacrylate and dimethacrylate, divinyl ether, tung oil and diamyl ethylene dimaleate and other monomers such as isoprene, butadiene, isobutylene, vinyl ethers, vinyl chloride, vinylidene chloride, acrylate and methacrylate esters, acrylonitrile, styrene and methyl vinyl ketone may be added to the monomers. The copolymers so prepared are used to impregnate porous paper and other fibrous material (see Group VIII).