Stock material or miscellaneous articles – Composite – Of fluorinated addition polymer from unsaturated monomers
Reexamination Certificate
2001-10-22
2004-08-17
Tarazano, D. Lawrence (Department: 1773)
Stock material or miscellaneous articles
Composite
Of fluorinated addition polymer from unsaturated monomers
C428S482000, C428S483000, C428S518000, C428S520000, C428S522000
Reexamination Certificate
active
06777089
ABSTRACT:
The invention relates to a radiation-curable composite layered sheet or film comprising at least one substrate layer and one outer layer, said outer layer being composed of a radiation-curable composition having a glass transition temperature of more than 40° C.
The specification further relates to a process for producing the radiation-curable composite layered sheet or film and to a process for producing moldings coated with said sheet or film.
DE-A-196 28 966 and DE-A-196 54 918 disclose dry-paint films where the paint has a glass transition temperature of less than 40° C. Curing requires two steps: a partial cure before the film is adhesively bonded to substrates, and the final cure thereafter.
EP-A-361 351 likewise discloses a dry-paint film. Here, the film is radiation-cured before being applied to the substrate moldings.
DE-A-196 51 350 (O.Z. 47587) describes composite layered sheets and films which consist of thermoplastic materials and do not have a radiation-curable coating.
A disadvantage of the radiation-curable dry-paint films known to date is that two or more steps are frequently required to effect the radiation cure, as described in DE-A-196 28 966. Where the film is fully radiation-cured prior to the coating operation, it often becomes brittle and difficult to deform, which is deleterious to its further processing.
With existing radiation-curable films, the coated moldings often lack sufficient scratch resistance and sufficient elasticity when worked on mechanically. It is an object of the present invention to provide radiation-curable composite layered sheets or films which are easy to process and which lend themselves to the coating of moldings by extremely simple techniques. The coated moldings are to have good mechanical properties, effective resistance to external influences, such as a good weathering stability, for example, and in particular are to be mechanically stable—having, for example, good scratch resistance and high elasticity.
We have found that this object is achieved by the radiation-curable composite layered sheet or film defined at the outset and referred to for short as film hereinafter. We have also found processes for coating moldings with the film, and the coated moldings.
The film must include a substrate layer and an outer layer which is applied to the substrate layer directly or, where there are further interlayers, indirectly.
Outer Layer
The outer layer is radiation-curable. Accordingly, the outer layer composition used is radiation-curable and comprises groups curable by a free-radical or ionic mechanism (curable groups for short). Preference is given to free-radically curable groups.
The radiation-curable composition is preferably transparent. After curing has been accomplished, as well, the outer layer is preferably transparent: that is, it is a clearcoat layer.
A key constituent of the radiation-curable compositions is the binder, which by filming forms the outer layer.
The radiation-curable composition preferably comprises a binder selected from
i) polymers containing ethylenically unsaturated groups
ii) mixtures of i) with ethylenically unsaturated compounds of low molecular mass
iii) mixtures of saturated thermoplastic polymers with ethylenically unsaturated compounds.
i)
Examples of suitable polymers include those of ethylenically unsaturated compounds, but also polyesters, polyethers, polycarbonates, polyepoxides or polyurethanes.
They suitably include unsaturated polyester resins, which consist essentially of polyols, especially diols, and polycarboxylic acid, especially dicarboxylic acid, where one of the esterification components contains a copolymerizable, ethylenically unsaturated group. Examples of the components in question include maleic acid, fumaric acid, and maleic anhydride.
Preference is given to polymers of ethylenically unsaturated compounds, such as are obtained in particular by means of free-radical addition polymerization.
The free-radical addition polymers include, in particular, polymers composed of more than 40% by weight, with particular preference more than 60% by weight, of acrylic monomers, particularly C
1
-C
8
, preferably C
1
-C
4
, alkyl (meth)acrylates. By way of ethylenically unsaturated groups, the polymers include in particular (meth)acrylic groups. These groups may be attached to the polymer by, for example, reacting (meth)acrylic acid with epoxide groups in the polymer (e.g., by using glycidyl (meth)acrylate as a comonomer).
Preference is likewise given to polyurethanes. Their unsaturated groups are again preferably (meth)acrylic groups, attached to the polyurethane by reacting hydroxyalkyl (meth)acrylates with isocyanate groups, for example.
The polymers i) per se can be processed as thermoplastics.
ii)
The unsaturated polymers i) may also be used in mixtures with ethylenically unsaturated compounds of low molecular mass.
Low molecular mass compounds in this context are compounds having a number average molecular weight of less than 2000 g/mol (as determined by gel permeation chromatography using a polystyrene standard).
Suitable examples include free-radically polymerizable compounds containing only one ethylenically unsaturated, copolymerizable group.
By way of example, mention may be made of C
1
-C
20
alkyl (meth)acrylates, vinylaromatics having up to 20 carbon atoms, vinyl esters of carboxylic acids containing up to 20 carbon atoms, ethylenically unsaturated nitriles, vinyl ethers of alcohols containing from 1 to 10 carbon atoms, and aliphatic hydrocarbons having from 2 to 20, preferably from 2 to 8, carbon atoms and 1 or 2 double bonds.
Preferred alkyl (meth)acrylates are those with a C
1
-C
10
alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate.
Also suitable, in particular, are mixtures of the alkyl (meth)acrylates.
Examples of vinyl esters of carboxylic acids having from 1 to 20 carbon atoms are vinyl laurate, vinyl stearate, vinyl propionate, and vinyl acetate.
Examples of suitable vinylaromatic compounds are vinyltoluene, &agr;-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, and preferably styrene.
Examples of nitrites are acrylonitrile and methacrylonitrile.
Examples of suitable vinyl ethers are vinyl methyl ether, vinyl isobutyl ether, vinyl hexyl ether, and vinyl octyl ether.
As nonaromatic hydrocarbons having from 2 to 20, preferably from 2 to 8, carbon atoms and one or two olefinic double bonds, mention may be made of butadiene, isoprene, and also ethylene, propylene, and isobutylene.
Compounds contemplated include preferably free-radically polymerizable compounds containing two or more ethylenically unsaturated groups.
The compounds in question are particularly (meth)acrylate compounds, with preference being given in each case to the acrylate compounds: i.e., the derivatives of acrylic acid.
Preferred (meth)acrylate compounds contain from 2 to 20, more preferably from 2 to 10, and with very particular preference from 2 to 6, copolymerizable, ethylenically unsaturated double bonds.
As (meth)acrylate compounds mention may be made of (meth)acrylates and in particular acrylates of polyfunctional alcohols, especially those which contain no functional groups other than the hydroxyl groups or, if having further functional groups, contain only ether groups. Examples of such alcohols include difunctional alcohols, such as ethylene glycol and propylene glycol, and their higher condensation analogs, such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, etc., butanediol, pentanediol, hexanediol, neopentyl glycol, alkoxylated phenolic compounds, such as ethoxylated and/or propoxylated bisphenols, cyclohexanedimethanol, alcohols with a functionality of three or more, such as glycerol, trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol, dimethylolpropane, dipentaerythritol, sorbitol, mannitol, and the corresponding alkoxylated alcohols, especially ethoxylated and propoxylated alcohols.
The alkoxylation products are obtainable conventionally by reacting the above alcoh
Aichholzer Walter
Beck Erich
Grefenstein Achim
Gruber Thomas
Holdik Karl
BASF - Aktiengesellschaft
Tarazano D. Lawrence
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