Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2001-04-09
2003-12-16
Tentoni, Leo B. (Department: 1732)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S272200, C264S293000, C264S485000, C264S544000
Reexamination Certificate
active
06663738
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a method for the preparation of a foil from a mass with a content of a non-interlaced polyolefin, of compound structures and shaped bodies made from same, as well as their utilization, for example as interior coverings of motor vehicles, in particular as dashboard foil.
Polyolefin foils are currently utilized in the most diverse sectors of the industry. Of particular significance is their utilization as packing material, as cover foil or in combination with other flat-shaped articles as compound structures. Another area of utilization is their further processing into shaped bodies, for example via deep-draw method. Frequently, the polyolefin foils and/or the composite structures and shaped bodies made from same are intended to also fulfill aesthetic functions. The mentioned areas of application require polyolefins to have a particular property spectrum, whereby said foils, in particular in connection with further processing by deep-draw method, shall at the same time have high mechanical stability and resistance toward aging and be embossable and capable of being laminated and have excellent grain stability.
According to the present state of the art, the polyolefin foil with the named properties is prepared by using partially interlaced polyolefin raw materials in mixture with other thermoplastic polyolefins. The partially interlaced raw materials are not obtainable as reactor products. In order to manufacture them it is, therefore, necessary to perform another reaction step after the polymerization. This additional reaction definitely raises the price for these products above the price level of polyolefin commodities. Another drawback of the previously employed method consists in that the polyolefin foil made from the mixture of partially interlaced polyolefin raw materials with other thermoplastic polyolefins is fixed with respect to its interlacing degree and thus with respect to its properties. A foil made of a given mixture is therefore only suitable for a given application spectrum.
SUMMARY OF THE INVENTION
The treatment by electron beams of polyolefin-containing flat-shaped articles for purposes of modification of mechanical properties is known from the state of the art. Thus, EP-A-0 425 695 describes an electron-beam interlaced path-shaped foam, which was obtained via a method which comprises an electron-beam hardening of a mixture of a polyolefin-containing homo- and copolymers and a gas-developing agent and subsequent foaming via thermal treatment. The technical purpose of electron-beam treatment consists in preventing the escape of the gas which develops during the thermal decomposition of the expanding agent by means of interlacing of the polymers on the surface of the foam. The developed foam has a density of 0.005 to 0.1 g/cm
3
. The subsequently described invention-specific method excludes foaming conditions.
Proceeding from said state of the art, it is the object of the present invention to make available a method for the preparation of polyolefin foils, which are embossable and capable of being laminated, which have excellent grain stability, and in addition, which, in comparison with foils prepared according to previous methods, can definitely be produced more cost-effectively. Furthermore, the invention-specific method shall open up the possibility of also influencing, within certain limitations, the mechanical properties of the polyolefin foils after forming the foils from the starter substances. Moreover, beneficial utilization of these polyolefin foils and/or of the composite structures made from same is being proposed.
According to the invention, this object is solved by means of a method for the preparation of a grained foil from a mass with a content of a non-interlaced polyolefin and, possible, another additive, whereby the obtained foil is treated with electron beams, characterized in that the foil obtained in the conventional manner is treated with electron beams in order to achieve a graining stability suitable for deep-drawing and the grained foil having a density of approximately 0.7 to 1.2 g/cm
3
is then deep drawn. As a result of targeted treatment with electron beams, a corresponding interlacing takes place with respect to the previously non-interlaced polyolefin.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The spectrum of the employed non-interlaced polyolefin is, on principle, not subject to any restriction. Preferably employed as non-interlaced polyolefins are: polyolefins such as PP, PE, poly(I-butene), polyisobutylene, poly(4-methylpentene), PP-copolymers or -terpolymers with C
2
, C
4
-C
12
-&agr;-olefins, PE-co-polymers or -terpolymers with C
3
to C
12
-&agr;-olefins or mixtures thereof, whereby diene monomers may also be employed as co or ter-monomers, which contain non-conjugated dual bonds, such as, for example, 1.4 hexadiene, 5-methyl-1.5-hexadiene, 5-ethylidene-2-norbornene, 5-butyliden-2-norbonene, dicyclopentadiene, 1.4-octadiene, cyclohexadiene or cyclo-octadiene; co-polymers of propylene and/or ethylene with polar co-monomers like acrylic acid and/or its C
1
-C
12
esters, methyl acrylic acid and/or its C
1
-C
12
esters, vinyl-esters, saturated C
2
-C
8
carbonic acids, optionally with carbon monoxide as ter-monomer, graft copolymers of propylene and/or ethylene with 8-45% grafted on units of unsaturated carbonic acids, dicarbonic acids, their esters and/or anhydrides as well as mixtures of the named polymers. Particularly preferentially employed are polypropylene, polyethylene, polypropylene-co-polymers or terpolymers with C
2
, C
4
-C
12
-&agr;-olefins and/or polyethylene-co-polymers or terpolymers with C
3
-C
12
-&agr;-olefins.
The polyolefins are preferably characterized prior to interlacing by a melt flow index MFI (230° C., 2.16 kg) of approximately 0.1 to 800 g/10 min., in particular approximately 0.1 to 200 g./10 min., most particularly preferred approximately 0.1 to 20 g/10 min.
In addition to the non-interlaced polyolefins, the mass employed for developing the foil can also contain additional components. There may thus also be present a percentage of pre-interlaced polymers, whereby said percentage is to be set up so that the above formulated object will be adequately complied with. These pre-interlaced polymers are preferably employed in a quantity which is smaller than 10%, preferably smaller than approximately 5% and in particular smaller than 3%.
In addition to the polymer constituents, the mass employed for the preparation of the foil preferably contains a series of auxiliary agents, such as interlacing substances, anti-oxidation means, light protection means and/or aging protection means. So as to obtain, for example, an adequate interlacing degree during the subsequent electron beam treatment, an interlacing auxiliary is preferably employed. This applies in particular to polyolefins for which the chain fission, which takes place as a concurrent reaction to the interlacing, produces notable effect. Affected are, in particular, polyolefins with tertiary and quaternary C-atoms. Employed as interlaing auxiliaries are, in particular, singly- or multiply-unsaturated compounds, such as acrylate of 1- or multi-valent alcohols, such as, for example, trimethylolpropantriacylate, methacrylate of 1 or multi-valent alcohols, such as, for example, trimethylolpropantrimethacrylate, vinyl-functional components, such as styrene and di-vinyl-benzol, allyl-compounds, such as triallycyanurate, triallylisocyante, sulfur, p-chinodioxime, N-methyl-N, 4-dinitrosaniline, nitrobenzol, diphenylguandine, trimethylolpropane-N,N′-m-phenylen-dimaleimide.
Trimethylolpropantrimethacrylate is particularly preferred as interlacing agent. In a beneficial specific embodiment, interlacing agents are employed in a quantity of up to approximately 20% by weight, preferably up to approximately 10% by weight, and, more particularly, of approximately 2 to 6% by weight in proportion to the contents of the mass of non-interlaced polyolefins. Preferably included are antioxidation means, espe
Bühring Jürgen
Ohlinger Rainer
Schäfer Burkhard
Benecka-Kaliko AG
Fay Sharpe Fagan Minnich & McKee LLP
Tentoni Leo B.
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