Film Membrane with Excellent Weather-Resistant Properties, High Transmission of Solar Thermal Radiation, Effective Retention of Thermal Radiation Emitted by the Earth and High Degree of Mechanical Strength and Method for Producing Said Film Membrane
The invention relates to a film membrane which has excellent weathering resistance and high permeability to thermal insolation, and is an effective barrier to thermal radiation emitted from the ground and has high mechanical strength, and also to a process for the production of the film membrane. The properties are achieved via a composite of a base film of thermoplastic and an outer layer of poly(meth)acrylate. The adhesion is achieved via copolymers with polar character. One or more layers of the plastics moulding may also have been equipped with flame retardants.
1 . Plastics moulding of multilayer structure, where the individual layers are composed of the following materials:
layer 1 of an olefinic polymer or of an ethyl-vinyl acetate polymer or of a copolymer of an olefin and ethyl-vinyl acetate,
layer 2 of a textile of oriented fibres of a thermoplastic polymer,
layer 3 of an olefinic polymer or of an ethyl-vinyl acetate polymer or of a copolymer of an olefin and ethyl-vinyl acetate,
layer 4 of an adhesion promoter,
layer 5 of a polymethyl methacrylate.
2 . Plastics moulding according to claim 1 ,
characterized in that
layer 1 has a thickness of from 20 to 100 μm,
layer 2 is composed of a textile of oriented fibres with dimensions from 8 mm×8 mm to 12 mm×12 mm fibres per inch (4.54 cm) 1400 to 800 dernier,
layer 3 has a thickness of from 0 μm to 100 μm,
layer 4 has a thickness of from 2 μm to 100 μm,
layer 5 has a thickness of from 5 μm to 150 μm.
3 . Plastics moulding according to claim 1 ,
characterized in that
layer 2 is composed of a high-density polyethylene (HDPE).
4 . Plastics moulding according to claim 1 ,
characterized in that
layer 1 and layer 3 are composed of
a) a polar copolymer of EVA and LDPE or
b) of EVA or
c) of LDPE or
d) of copolymers of LDPE and polar comonomers or
e) of copolymers of PE and polar comonomers.
5 . Plastics moulding according to claim 1 ,
characterized in that
layer 4 is composed of copolymers of PE and other, polar monomers.
6 . Plastics moulding according to claim 1 ,
characterized in that
layer 4 is composed of a solvent-based adhesive.
7 . Plastics moulding according to claim 1 ,
characterized in that
layer 4 is composed of a modified PE.
8 . Plastics moulding according to claim 1 ,
characterized in that
layer 5 is composed of a PMMA copolymer of the following constitution: of polymerized monomer mixtures a, b and, if appropriate, c, where a. comprises:
A) from 20 to 100% by weight of methyl meth-acrylate,
B) from 0 to 80% by weight of a (meth)acrylate of the formula I, other than methyl meth-acrylate,
where
R 1 is hydrogen or methyl and
R 2 is a linear or branched alkyl radical or cycloalkyl radical having from 1 to 18 carbon atoms or is phenyl or naphthyl,
C) from 0 to 40% by weight of a further unsaturated monomer other than a.A) and a.B), but copolymerizable with these, where (a.A) to (a.C) together give 100% by weight, and from 0 to 80 parts by weight of further polymers, and also amounts of from 0 to 150 parts by weight of conventional additives, are added to 100 parts by weight of this polymerized mixture;
and b. comprises:
A) from 20 to 99% by weight of a methyl (meth)-acrylate of the formula I,
where
R 1 is hydrogen or methyl and
R 2 is a linear or branched alkyl radical or cycloalkyl radical having from 1 to 18 carbon atoms, or is phenyl or naphthyl,
B) from 1 to 80% by weight of one or more ethylenically unsaturated “reactive monomers” other than b.A) but copolymerizable with (b.A), where (b.A) and (b.B) together give 100% by weight, and where from 0 to 80 parts by weight of further polymers, and also amounts of from 0 to 150 parts by weight of conventional additives, are added to 100 parts by weight of this polymerized mixture
and the ratio by weight between a. and b. can be from 50:50 to 100:0,
and the optionally present component c. can be a polymer.
9 . Plastics moulding according to claim 8 ,
characterized in that
the PMMA polymer has been rendered impact-resistant.
10 . Plastics moulding according to claim 8 ,
characterized in that
the component c. used comprises a polymer from the group consisting of polyvinylidene fluoride, polyvinyl chloride, polyethylene, polypropylene, polyester or polyamides, and the polymer a is replaced either completely or to some extent by the polymer c.
11 . Process for the extrusion coating of plastics mouldings,
characterized in that
a first layer composed of a further plastic is applied to the lower side of the plastics moulding, and optionally, in a second step preferably to be carried out simultaneously with the first step, a second plastics layer is applied to the upper side of the plastics moulding, and then a third plastics layer is applied to the upper side of the second plastics layer, and then the PMMA layer is applied as final layer.
12 . Process for the extrusion coating of plastics mouldings according to claim 11 ,
characterized in that
one or more flame retardants is/are added to one or more of the layers 1 to 5.
13 . Process for the extrusion coating of plastics mouldings according to claim 11 or 12 ,
characterized in that
the layers 4 and 5 are applied in the form of a multilayer melt film.
14 . Process for the extrusion coating of plastics mouldings according to any of claims 11 to 13 ,
characterized in that,
preferably in one simultaneous operation, layer 1 is extruded onto the lower side of layer 2 and layers 3 to 5 are extruded in the form of a multi-layer melt film (coextrudate) onto the upper side of layer 2.
15 . Plastics moulding according to claim 8 ,
characterized in that
use is made of light stabilizers, such as UV absorbers and HALS (hindered amine light stabilizers).
16 . Plastics moulding according to claim 15 ,
characterized in that
the UV absorbers used comprise triazines.
17 . Use of the plastics moulding according to claim 1 in outdoor applications, such as greenhouse films and architectural membranes.