| 摘要 |
<p>Novel graft copolmers comprise 5 to 40% by weight of a grafting substrate (A) which is a saturated copolymer of 1 to 30% by weight of p-isopropyl-a -methylstyrene and 99 to 70% by weight of an ester of acrylic or methacrylic acid with an alcohol moiety containing 1 to 10 carbon atoms, with 95 to 60% by weight of a grafted component (B) which comprises at least one ester of acrylic acid with 1 to 10 carbon atoms in the alcohol moiety, the overall proportion of p-isopropyl-a -methylstyrene in the graft copolymer being at least 0.3% by weight. The grafted component (B) preferably comprises up to 50% by weight of one or more other compounds having a CH2=C=group, which are copolymerizable with the acrylic ester monomer. The alcohol moieties of the ester constituents of components (A) and (B) may be, for example, methanol, ethanol, n-propanol, n-butanol, 2-ethyl-hexanol, n-decanol and cyclohexanol. As the optional comonomer constituent of component (B) there are specified methyl methacrylate, acrylamide, methacrylamide, methacrylonitrile, styrene and substituted styrenes, acrylic, methacrylic and styrene-sulphonic acids, vinylpyridine, N,N-dimethylaminoethyl methacrylate, vinyl chloride, vinylidene chloride and, particularly, compounds containing spontaneously cross-linking groups such as methylol ether, Mannich base and methylol ester derivatives of acrylamide and methacrylamide (many examples of these cross-linking monomers are listed). The graft copolymers may be prepared by polymerizing component (B) monomers in the presence of component (A) copolymer in aqueous emulsion or in organic solvents using a free-radical catalyst, e.g. a peroxy or redox catalyst. In examples, component (A) is a copolymer of p-isopropyl-a -methylstyrene with n-butyl or ethyl acrylate, prepared by the emulsion polymerization of the appropriate monomers using a potassium persulphate-sodium pyrosulphite (metabisulphite) catalyst. The graft copolymers are particularly suitable for consolidating fleeces, coating fabrics and as adhesives in laminating, being used in the form of powders, solutions or aqueous emulsions. Such compositions may include cross-linking agents, e.g. urea-formaldehyde or melamine-formaldehyde prepolymers and hydrogen ion donors, surfactants, e.g. alkyl benzenesulphonates, foam stabilizers, e.g. KA1(SO4)2, ammonium polyacrylate and dibutyl phthalate.ALSO:Solutions and aqueous emulsions of novel graft copolymers are suitable for various coating applications, particularly in the coating of textile materials. The graft copolymers comprise 5 to 40% by weight of a grafting substrate which is a copolymer of p-isopropyl-a -methylstyrene and an ester of a C1-C10 alcohol with acrylic or methacrylic acid, and 95 to 60% by weight of a grafted component comprising at least one ester of a C1-C10 alcohol with acrylic acid and, optionally, up to 50% by weight of one or more other compounds containing a CH2=C= group, the overall proportion of p-isopropyl-a -methylstyrene in the graft copolymer being at least 0.3% by weight. The compositions may optionally include cross-linking agents, e.g. urea-formaldehyde or melamine-formaldehyde prepolymers and acid compounds such as phosphoric, maleic and tartaric acids, ammonium phosphate, ammonium nitrate or ammonium thiocyanate, surfactants, e.g. alkylbenzene sulphonates, foam stabilizers, e.g. KAl(SO4)2, ammonium polyacrylate, and dibutyl phthalate. In Examples (11) a graft copolymer emulsion is applied with a doctor blade to a roughened textile fabric and a 2 mm./10 den. polyamide flock is applied electrostatically thereon and fixed for 10 minutes at 120-140 DEG C (13) a graft copolymer emulsion is applied with a floating doctor to a cotton fabric and dried for 2 minutes at 80 DEG C, and further coatings are applied with rubber cloth doctors, the coatings being finally cured for 3 minutes at 140 DEG C.ALSO:Fleeces of various fibres are consolidated by means of novel graft copolymers comprising 5 to 40% by weight of a grafting substrate which is a copolymer of p-isopropyl-a -methylstyrene and an ester of a C1-C10 alcohol with acrylic or methacrylic acid, and 95 to 60% by weight of a grafted component comprising at least one ester of a C1 - C10 alcohol with acrylic acid and, optionally, up to 50% by weight of one or more other compounds containing a CH2 = C = group, the overall proportion of p-isopropyl-a -methylstyrene in the graft copolymer being at least 0.3% by weight. The polymers may be applied in the form of powders, solutions or aqueous emulsions. In such compositions, optional ingredients include cross-linking agents, e.g. urea-formaldehyde or melamine-formaldehyde prepolymers and acid compounds such as phosphoric, maleic and tartaric acids, ammonium phosphate, ammonium nitrate or ammonium thiocyanate, surfactants, e.g. alkylbenzenesulphonates, foam stabilizers, e.g. K Al (SO4)2, ammonium polyacrylate, and dibutyl phthalate. The fleeces may be derived from, for example, cellulose, cellulose derivatives, proteins or modified proteins, polyamides, polyesters, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyolefines, vinylidene-chloride-acrylonitrile copolymers, vinylidene cyanide-vinyl acetate copolymers, polyvinyl alcohol, glass and asbestos. The fleeces may also be composed of mixtures of fibres. Fibrous materials such as paper and leather may also be treated with the graft copolymers. The polymers, in emulsion, can be applied to the fleeces by impregnation, spraying or foaming, or by using a two-step procedure of (i) spraying a loose fleece and (ii) finally consolidating by impregnation. Drying of the fleeces is generally effected at 100-200 DEG C. Examples illustrate the treatment of needle-loomed fleeces of crossed layers of copper cellulose, with several graft copolymers of the invention.</p> |
