Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2001-08-21
2003-10-28
Cain, Edward J. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S406000, C524S407000, C524S408000
Reexamination Certificate
active
06639001
ABSTRACT:
BACKGROUND OF THE INVENTION
Molded workpieces of any three-dimensional form, including polyolefin-based moldings, fibers and films, are used on a very wide scale in practice. An important problem area here is improving the surface properties of these structurally nonpolar hydrocarbon components. Thus, the poor adhesion of coatings and adhesives is a central problem which has remained unsolved for decades despite numerous attempts to find a solution.
It is known from the prior art that the compatibility of plastic surfaces with coatings and adhesives can be improved, for example, by oxidative aftertreatment processes, such as corona or plasma treatment. In processes such as these, the surface of the plastic is oxidized or chemically modified in the presence of gases and discharges, so that certain surface properties of the plastic can be modified. However, apart from their high energy consumption, processes such as these always involve an additional step and lead to ozone emissions in the manufacture of plastic parts. In addition, chemical pretreatment processes, including for example treatment with fluorine or chlorine gas, with chromosulfuric acid or fluorosulfonic acid, etc., have also been known for some time.
EP-B-372 890 describes polyolefin- or polyester-based fibers with a lubricant adhesively applied to their surface. This lubricant comprises a mixture of (1) fatty acid diethanolamide, (2) a polyether-modified silicone, (3) a sorbitan fatty acid ester and (4) a metal salt of an alkyl sulfonate. Components (1) to (4) are present in special quantity ratios. According to page 3, lines 20 to 26, the mixture of components (1) to (4) is applied to the surface. The technique by which the mixture containing the four components is applied to the surface of fibers is described in detail on page 4, lines 6 to 9. The application techniques mentioned include a) the use of rollers, b) spraying and c) immersion. Accordingly, the process according to EP-B-372 890 is a process in which a mixture of components (1) to (4) is applied to the surface of polyolefin moldings in an additional process step. Accordingly, the expression “adhesively applied to the fiber surface” used in claim 1 of EP-B-372 890 may be clearly interpreted by the expert to mean that any adhesion involved is loose and temporary, for example in the form of relatively weak adhesion forces, and cannot in any way to be considered to represent permanent anchorage.
In view of the very widely used traditional chemical aftertreatment processes, such as corona and plasma treatment, it is known to the expert that no exact statements can be made as to the various processes involved. However, it has been established that oxidative surface changes occur and result in the formation of certain “active centers”. Unfortunately, their concentration generally decreases with time so that the pretreatment effect also is only in evidence for a certain time, generally not more than 72 hours (cf. for example, Klaus Stoeckert (Editor), “Veredeln von Kunststoff-Oberflächen”, Munich 1974, page 137).
One feature common to all the known processes is that, in general, the desired surface effects are only temporarily present.
EP-B-616 622 relates to extrudable compostable polymer compositions comprising an extrudable thermoplastic polymer, copolymer or mixtures thereof containing a degradation-promoting system of an auto-oxidative component and a transition metal. The auto-oxidative system comprises a fatty acid, a substituted fatty acid or derivatives or mixtures thereof, the fatty acid having 10 to 22 carbon atoms and containing at least 0.1% by weight of unsaturated compounds and at least 0.1% by weight of free acid. The transition metal is present in the composition in the form of a salt in a quantity of 5 to 500 ppm and is selected from the group consisting of cobalt, manganese, copper, cerium, vanadium and iron. In the form of a film around 100 microns thick, the composition is said to be oxidatively degradable to a brittle material over a period of 14 days at 60° C. and at a relative air humidity of at least 80%.
WO 97/12694 and WO 98/42776 describe the use of amphiphiles for permanently improving the adhesive and/or coating compatibility of polyolefin-based moldings, fibers and films in which a mixture containing (a) predominantly one or more polyolefins, (b) one or more migratable amphiphiles and (c) of one or more transition metal compounds is subjected in the usual way to molding, for example by extrusion, at temperatures in the range from 180 to 320° C. It is disclosed that dialkanolamides of unsaturated fatty acids, for example oleic acid diethanolamide or linoleic acid diethanolamide, are particularly suitable for use as component (b). So far as the nature of component (c) is concerned, WO 97/12694 makes particular mention of Co, Zr, Fe, Pb, Mn, Ni, Cr, V and Ce while WO 98/42776 refers in particular to Ti and Sn as the transition metal present in that component.
BRIEF SUMMARY OF THE INVENTION
The present invention relates, in general, to methods of permanently improving the adhesive and/or coating compatibility of polyolefin-based moldings, fibers and films with the use of fatty acid amides.
The problem addressed by the present invention was to provide auxiliaries with which the adhesive and/or coating compatibility of polyolefin-based moldings, fibers and films could be lastingly and permanently improved. In other words, the object of the invention was to provide auxiliaries for permanently improving the affinity of polyolefin surfaces for adhesives and/or coatings. More particularly, the object of invention was to make it possible to establish high-strength bonds which would rule out unwanted adhesive failures and would ensure that the adhesive joint could only be destroyed by cohesive failure or by combined cohesive/adhesive failure. In particular, the effectiveness of the amphiphiles known from the prior art in permanently improving the adhesive and/or coating compatibility of polyolefin-based moldings, fibers and films would be quantitatively improved.
The present invention relates to the use of fatty acid amides for permanently improving the adhesive and/or coating compatibility of polyolefin-based moldings, fibers and films, a mixture containing
a) predominantly one or more polyolefins,
b) 0.01 to 20% by weight—based on the polyolefins—of one or more fatty acid amides and
c) 0.01 to 1000 ppm of one or more transition metal compounds—metal content of the transition metal compounds, based on the polyolefins—being subjected in known manner to molding by extrusion, calendering, injection molding, blow molding and the like at temperatures of 180 to 330° C., with the proviso that the fatty acid amides b) are selected from the class of compounds corresponding to general formula (I):
in which R
1
is a saturated alkyl group containing 5 to 21 carbon atoms, R
2
and R
3
independently of one another are hydrogen or alkyl groups containing 1 to 18 carbon atoms which may each be substituted by up to 6 OH groups, NH
2
groups or C
1-10
alkyl groups and in which up to three ethylene groups which are not immediately adjacent one another may be replaced by oxygen, with the proviso that R
1
and R
2
cannot both be hydrogen and the additional proviso that the mixture containing components a), b) and c) contains fatty acid amides based on unsaturated fatty acids at most in a quantity which corresponds to 40% by weight, based on the quantity of fatty acid amides b) based on saturated fatty acids.
“Transition metals” in the context of the present invention are any transition metals in the narrower sense (cf. for example Römpps Chemie-Lexikon, Stuttgart 1977, pp. 3717) and, in addition, the metals tin (Sn) and lead (Pb).
The fatty acid amides b) of general formula (I) to be used in accordance with the invention are derived from C
6-22
fatty acids. These fatty acids are characterized by the general formula (II) R
1
—COOH, in which R
1
is as defined above.
DETAILED DESCRIPTION OF THE INVENTION
In one embodiment, the fatty acid amides b) are fa
Birnbrich Paul
Klamann Joerg-Dieter
Tenhaef Rolf
Cain Edward J.
Cognis Deutschland GmbH & Co. KG
Drach John E.
Ettelman Aaron R.
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