摘要:
A process for producing polycarboxylic acids or their salts from polysaccharides is provided. Solid particulate polysaccharides having at least one primary alcohol group in the polysaccharides are oxidized with nitrogen dioxide in a fluid bed. The fluidizing gas contains nitrogen dioxide and the process is operated at a pressure of from 0.5 to 12 bars and a temperature between the boiling point of nitrogen dioxide and 160.degree. C. At least two moles of nitrogen dioxide for the equivalent of the primary alcohol groups reacted over the entire reaction are provided.
摘要:
A process for producing polycarboxylic acids or salts thereof by contacting a polysaccharide with nitrogen dioxide and dinitrogen tetroxide at a charging temperature in the range from the boiling point of nitrogen dioxide under a particular pressure to a temperature which is 50.degree. C. higher than said boiling point, oxidizing the primary alcohol groups of the polysaccharide at a temperature which is at least about 10.degree. C. above said charging temperature to convert the primary alcohol groups into carboxyl groups, and optionally, at least partially neutralizing the carboxylic acid groups formed.
摘要:
The invention relates to a contact adhesive based on a polyurethane of at least one diisocyanate and at least one low molecular weight polyethylene glycol, the polyethylene glycol having a molecular weight of up to 2,000 and the polyurethane having a degrees of crystallization of less than 20%. The contact adhesive can be applied from the melt or from an aqueous solution or dispersion. Surprisingly, it is suitable not only for polar plastic surface, but above all for PE and PP surfaces and of course for paper. Accordingly, the contact adhesive is preferably useful for applying paper labels to PE bottles.
摘要:
A process for producing solid polycarboxylic acid salts from polysaccharides with gaseous nitrogen dioxide and dinitrogen tetroxide to at least partially convert the primary alcohol groups of the polysaccharides into carboxyl groups and form a solid polycarboxylic acid and then mixing the polycarboxylic acid with a solid neutralizing agent to at least partially neutralized the carboxylic acid groups of the polycarboxylic acid.
摘要:
The process of controlling foam in a foam-generating system by adding to the system a foam-inhibiting effective amount of a block copolymer containing alkylene oxide units obtained by reacting a homopolymer or copolymer of alkylene oxides with a diisocyanate or a dicarboxylic acid derivative containing 2 to 44 carbon atoms.
摘要:
A method for increasing an adhesive to a substrate is disclosed which utilizes a hydrophilic, high molecular weight, nonionic polyurethane adhesive. The polyurethane adhesive is soluble in water and a 1% by weight solution of the adhesive in water at 20% has a specific viscosity of at least 0.4. The nonionic polyurethane contains the following structural units: a) —O—(CH2—CH2O)n where n is 8 to 500; b) —CO—NH—X—NHCO— where X is an aliphatic or cycloaliphatic group; and c) —O—Y—O— wherein Y comprises a hydrophobic moiety from the groups (—CH2—CH(CH3)—O)m—CH2—CH(CH3)—, (—CH2 CH(C2H5)—O)m—CH2—CH(C2H5)—, (—CH2—CH2—CH2—CH2O)m—CH2CH2CH2CH2—, alkylene groups having from 2 to 44 carbon atoms, cycloalkylene groups having from 6 to 44 carbon atoms and mixtures thereof.
摘要:
A method of applying an adhesive to a substrate is disclosed which utilizes a hydrophilic, high molecular weight, nonionic polyurethane adhesive. The polyurethane adhesive is soluble in water and a 1% by weight solution of the adhesive in water at 20% has a specific viscosity of at least 0.4. The nonionic polyurethane contains the following structural units: a) —O—(CH2—CH2O)n where n is 8 to 500; b) —CO—NH—X—NHCO— where X is an aliphatic or cycloaliphatic group; and c) —O—Y—O— wherein Y comprises a hydrophobic moiety from the groups (—CH2—CH(CH3)—O)m—CH2—CH(CH3)—, (—CH2 CH(C2H5)—O)m—CH2—CH(C2H5)—, (—CH2—CH2—CH2—CH2 O)m—CH2 CH2 CH2 CH2—, alkylene groups having from 2 to 44 carbon atoms, cycloalkylene groups having from 6 to 44 carbon atoms and mixtures thereof
摘要:
A hydrophilic, high molecular weight nonionic polyurethane, characterized by solubility in water and by a specific viscosity of at least 0.4 (1% by weight solution at 20° C.) is provided. Examples of such polyurethanes are those characterized by the following structural units: a) —O(—CH2—CH2—O)n—, where n=8 to 500, and b) —CO—NH—X—NH—CO—, where X is an aliphatic or cycloaliphatic radical. Also provided are methods of using the polyurethane as an adhesive, more particularly a hotmelt adhesive or a solvent-based adhesive, for example a wallpaper adhesive and labelling adhesive, of using polyurethane as a stabilizer in the emulsion polymerization of, in particular, vinyl acetate and vinyl chloride and in the copolymerization of ethylene and vinyl acetate, and of using the polyurethane as a thickener for aqueous systems, more particularly together with nonionic surfactants.
摘要:
The invention relates to block copolymers produced by means of controlled polymerization and that have at least one block A or B comprising (meth)acrylate monomers and copolymerizable monomers, and a block P on the basis of functionalized polymers.
摘要:
Hot-melt adhesives containing at least one aromatic modified polyethylene and/or polypropylene (co)polymer, a further ethylene or propylene/C4 to C20 alpha-olefin copolymer, and at least one tackifying resin are useful for the adhesive bonding of package and paperboard products.
摘要翻译:含有至少一种芳族改性聚乙烯和/或聚丙烯(共)聚合物,另外的乙烯或丙烯/ C 4至C 20α-烯烃共聚物和至少一种增粘树脂的热熔粘合剂可用于包装和纸板的粘合 产品。