SYNTHETIC FILM PRIMARILY CONSISTING OF BIODEGRADABLE POLYMERS
The present invention relates to a single- or multi-layered synthetic film primarily consisting of biodegradable polymers, said synthetic film consisting of one or more layers (a) of at least one biodegradable polymer and 1-35% by weight, relative to the total weight of the layer (a), of at least one modified, thermoplastic copolymer of α,β-unsaturated olefins having 2-10 carbon atoms and (meth)acrylic acid and/or at least one (meth)acrylic acid derivative that is grafted, preferably with cyclic anhydride groups and/or carboxyl groups and/or ester groups, said invention further relating to a use of such a synthetic film as packaging material.
1 . A predominantly biodegradable, single-layer or multilayer polymer film consisting of
at least one layer (a) made up of a mixture of at least one biodegradable polymer and up to a maximum of 35% by weight, based on the total weight of the layer (a), of at least one modified, thermoplastic copolymer composed of α,β-unsaturated olefins having 2-10 carbon atoms and (meth)acrylic acid and/or at least one (meth)acrylic acid derivative, which is grafted, of optionally at least one plasticizer and of optionally one or more commonly used additives; and
additionally optionally other layers;
whereby the other layers which are optionally present consist of at least one biodegradable polymer, of optionally a modified, thermoplastic copolymer of α,β-unsaturated olefins having 2-10 carbon atoms and (meth)acrylic acid and/or at least one (meth)acrylic acid derivative, which is grafted, of optionally at least one plasticizer and of optionally one or more commonly used additives,
whereas the total proportion of the modified, thermoplastic copolymers of the polymer film, based on the total weight of the polymer film, is not more than 15% by weight and
the polymer film comprises no adhesion promoting layer.
2 . A polymer film as claimed in claim 1 , wherein the polymer film is a multilayer film.
3 . A polymer film as claimed in claim 1 , wherein the modified, thermoplastic copolymer is at least one polymer selected from the group consisting of copolymers of ethylene and methacrylic acid, copolymers of ethylene and methacrylate, copolymers of ethylene and acrylic acid and copolymers of ethylene and acrylate, in each case grafted.
4 . A polymer film as claimed in claim 1 , wherein the modified thermoplastic copolymer is present in an amount of 1-30% by weight, based on the total weight of the respective layer (a).
5 . A polymer film as claimed in claim 1 , wherein the total proportion of the modified thermoplastic copolymer in the polymer film is not more than 10% by weight, based on the total weight of the polymer film.
6 . A polymer film as claimed in claim 1 , wherein each layer is predominantly biodegradable.
7 . A polymer film as claimed in claim 1 , wherein the biodegradable polymer is at least one biodegradable synthetic polymer selected from the group consisting of lactic acid homopolymers and copolymers, polyhydroxyalkanoates, polyesters derived from lactones having 4 to 10 carbon atoms, and copolymers of at least two monomers of the polymers mentioned and mixtures of at least two of the polymers mentioned.
8 . A polymer film as claimed in claim 7 , wherein the biodegradable polymer is at least one polylactide, and the polylactide is a poly-L-lactide, poly-D-lactide, poly-DL-lactide or an isomeric, optionally racemic, mixture of poly-L-lactide and poly-D-lactide.
9 . A polymer film as claimed in claim 1 , wherein the polymer film contains at least one plasticizer in one or more layers.
10 . A polymer film as claimed in claim 9 , wherein the plasticizer is present in at least one layer (a) in an amount of 1-20% by weight, based on the total weight of the layer (a).
11 . A polymer film as claimed in claim 1 , wherein the plasticizer content in at least one interior layer is greater than in the surface layers.
12 . A polymer film as claimed in claim 1 , wherein the polymer film was produced as cast film.
13 . A polymer film as claimed in claim 1 , wherein the polymer film is transparent or is provided with a layer of self-adhesive material.
14 . A method of packaging a consumer good, said method comprising packaging the consumer good in a polymer film as claimed in claim 1 .
15 . A method of using a polymer film as claimed in claim 1 as viewing window for otherwise nontransparent packaging, as viewing window of envelopes, as stickers which are optionally provided with a pressure-sensitive adhesive layer, as inscribed or uninscribed labels or optionally printed as protective or decorative film for books and cartons.
16 . A package comprising a consumer good packaged within a packaging comprising a polymer film as claimed in claim 1 .
17 . A viewing window, a sticker, a label or a protective or decorative film composed of a polymer film as claimed in claim 1 .