Use of polymers for starch modification
Polymers stabilized by protective colloids and/or emulsifiers and consisting of at least one comonomer unit from the group consisting of vinyl esters of utinbranched or branched alkyl carboxylic acids containing between 1 and 18 C atoms, acrylic acid esters or methacrylic acid esters of branched or unbranched alcohols containing between 1 and 15 C atoms, dienes, olefins, vinyl aromates and vinyl halogenides, optionally containing between 0.1 and 20 wt. % more of functional comonomer units from the group comprising carboxyl-functional, hydroxyl-functional and NH-functional, ethylenically unsaturated comonomers, are useful as additives to moldable starch compositions.
1 - 19 . (canceled)
20 . In a starch molding composition or molding prepared therefrom, wherein optionally modified starch is combined with at least one polymer additive, the improvement comprising selecting as at least one polymer additive, a polymer stabilized with protective colloid(s) and/or emulsifier(s), said polymer comprising one or more comonomer units selected from the group consisting of vinyl esters of straight-chain and branched alkylcarboxylic acids having 1 to 18 carbon atoms, acrylates and methacrylates of branched and straight-chain alcohols having 1 to 15 carbon atoms, dienes, olefins, vinylaromatics and vinyl halides, said polymers optionally also containing from 0.1 to 20.0% by weight of at least one functional comonomer unit selected from the group consisting of carboxyl-, hydroxyl-, epoxy- and NH-functional, ethylenically unsaturated comonomers, and hydroxyalkyl acrylates and hydroxyalkyl methacrylates having a C 1 - to C 8 -alkyl radical, and optionally, olefin comonomer(s), the data in % by weight being based on the total weight of the polymer.
21 . The starch molding composition or molding prepared therefrom of claim 1 , wherein polymers comprising one or more comonomer units selected from the group consisting of vinyl esters of straight-chain or branched carboxylic acids having 1 to 18 carbon atoms are used.
22 . The starch molding composition or molding prepared therefrom of claim 1 , wherein the N-alkylol-functional comonomer units having a C 1 - to C 4 -alkylol radical are contained.
23 . The starch molding composition or molding prepared therefrom of claim 3 , wherein one or more comonomer units derived from N-methylolacrylamide (NMA), N-methylolmethacrylamide, N-methylolallylcarbamate, C 1 - to C 4 -alkyl ethers of N-methylolacrylamide, N-methylolmethacrylamide and N-methylolallylcarbamate, and C 1 - to C 4 -alkyl esters of N-methylolacrylamide, of N-methylolmethacrylamide and of N-methylolallylcarbamate are employed.
24 . The starch molding composition or molding prepared therefrom of claim 20 , wherein the polymers are vinyl acetate polymers, vinyl acetate/ethylene copolymers, vinyl acetate/ethylene/vinyl chloride copolymers or vinyl ester/acrylate copolymers, each further containing said functional comonomer.
25 . The starch molding composition or molding prepared therefrom of claim 20 , wherein the polymers have a glass transition temperature of from −30° C. to +120° C.
26 . The starch molding composition or molding prepared therefrom of claim 20 , wherein the amount of protective colloid is from 1 to 30% by weight, based on the weight of the polymer.
27 . The starch molding composition or molding prepared therefrom of claim 20 , wherein one or more protective colloids from the group consisting of polyvinyl alcohols, polyvinyl acetals, polyvinylpyrrolidones, celluloses, cellulose derivatives, poly(meth)acrylic acid, copolymers of (meth)acrylates with carboxy-functional comonomer units, poly(meth)acrylamide, polyvinylsulfonic acids and copolymers thereof, melamineformaldehydesulfonates, naphthaleneformaldehydesulfonates, styrene/maleic acid and vinyl ether/maleic acid copolymers, starch and dextrins are contained as the protective colloid.
28 . The starch molding composition or molding prepared therefrom of claim 27 , wherein polyvinyl alcohols having a degree of hydrolysis of from 85 to 94 mol % and a Höppler viscosity, in 4% strength aqueous solution, of from 3 to 15 mPa·s at 20° C. according to DIN 53015 are contained as the protective colloid.
29 . The starch molding composition or molding prepared therefrom of claim 20 , wherein the starch is used in natural form, as destructured starch, as chemically modified starch, or a mixture thereof.
30 . The starch molding composition or molding prepared therefrom of claim 20 , which is an adhesive.
31 . A molding of claim 20 , prepared by a molding process of extrusion, extrusion blow molding, foam extrusion, injection molding, calendering or thermoforming.
32 . The molding of claim 31 , wherein the starch composition further comprises an additional binder comprising biodegradable polyester.
33 . The molding of claim 31 , wherein the starch composition further comprises cellulose fractions in the form of wood particles, wood fibers and woodmeal.
34 . The molding of claim 31 , wherein said molding is a rottable molding.
35 . The molding of claim 31 , which is a rottable film.
36 . A process for producing a molding of claim 20 , comprising:
providing starch, mixing said at least one polymer with said starch, and molding at a temperature of from 70° C. to 150° C.
37 . The process of claim 36 , wherein water is present prior to molding.
38 . The process of claim 36 , wherein a wood product selected from the group consisting of wood particles, wood fibers, wood meal, and mixtures thereof are present prior to molding.