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
1999-12-17
2001-03-06
Michl, Paul R. (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...
Reexamination Certificate
active
06197872
ABSTRACT:
The invention relates to sheet-like wall elements and also fastening parts therefor. In particular the invention relates to sheet-like wall elements which have good dimensional stability together with low density and low weight, good chemicals resistance and high scratch resistance.
Various materials have hitherto been used for producing sheet-like wall elements, such as visual privacy partitions in the interior of buildings, for example changing cubicles in sports facilities and other installations. Use is made, for example, of timber products, such as plywood, particle board and other boards, and also, less frequently, of metal sheets. Polymeric materials, such as PVC (polyvinyl chloride), ABS (acrylonitrile-butadiene-styrene copolymer) and PP (polypropylene) are also used in place of naturally occurring materials.
It is an object of the present invention to provide sheet-like wall elements which can be produced in a single-step process without post-treatment and have good dimensional stability. A further object of the invention is to provide sheet-like wall elements which have low density and therefore low weight, but nevertheless are stable. A further object of the invention is to provide sheet-like wall elements which have good chemicals resistance and high scratch resistance. A further object of the present invention is to provide sheet-like wall elements which have properties superior to those of the wall elements used hitherto.
We have found that this object is achieved by using a thermoplastic molding composition differing from ABS and comprising, based on a total of 100% by weight of amounts of components A and B, and, if desired, C and/or D,
a: as component A, from 1 to 99% by weight of a particulate emulsion polymer with a glass transition temperature of below 0° C. and with a median particle size of from 50 to 1000 nm,
b: as component B, from 1 to 99% by weight of at least one amorphous or partly crystalline polymer,
c: as component C, from 0 to 50% by weight of polycarbonates, and
d: as component D, from 0 to 50% by weight of fibrous or particulate fillers or mixtures of these
for producing sheet-like wall elements and fastening parts therefor.
The sheet-like wall elements described are scratch-resistant, stable and resistant to chemicals and have very good dimensional stability. They have low density and thus a low weight.
The thermoplastic molding compositions used according to the invention for producing the novel sheet-like wall elements are known per se. Molding compositions which can be used according to the invention are described, for example, in DE-A-12 60 135, DE-C-19 11 882, DE-A-28 26 925, DE-A-31 49 358, DE-A-32 27 555 and DE-A-40 11 162.
In one embodiment, the molding compositions differing from ABS and used according to the invention for producing the novel sheet-like wall elements comprise the components listed below: A and B, and, if desired, C and/or D, as defined further below. Based on amounts of components A and B, and if desired, C and/or D, which give 100% in total, they comprise
a: as component A, from 1 to 99% by weight, preferably from 15 to 60% by weight, in particular from 25 to 50% by weight, of a particulate emulsion polymer with a glass transition temperature of below 0° C. and with a median particle size of from 50 to 1000 nm, preferably from 50 to 500 nm
b: as component B, from 1 to 99% by weight, preferably from 40 to 85% by weight, in particular from 50 to 75% by weight, of at least one amorphous or partly crystalline polymer,
c: as component C, from 0 to 50% by weight of polycarbonates, and
as component D, from 0 to 50% by weight of fibrous or particulate fillers or mixtures of these.
The invention is described in more detail below.
The molding compositions used for producing the novel sheet-like wall elements are firstly described together with the components of which these compositions are composed.
COMPONENT A
Component A is a particulate emulsion polymer with a glass transition temperature of below 0° C. and with a median particle size of from 50 to 1000 nm.
Component A is preferably a graft copolymer made from
a1: from 1 to 99% by weight, preferably from 55 to 80% by weight, in particular from 55 to 65% by weight, of a particulate graft base A1 with a glass transition temperature of below 0° C.,
a2: from 1 to 99% by weight, preferably from 20 to 45% by weight, in particular from 35 to 45% by weight, of a graft A2 made from the monomers, based on A2,
a21: as component A21, from 40 to 100% by weight, preferably from 65 to 85% by weight, of units of a vinylaromatic monomer, preferably of styrene, of a substituted styrene or of a (meth)acrylate or mixtures of these, in particular of styrene and/or of &agr;-methylstyrene, and
a22: as component A22, up to 60% by weight, preferably from 15 to 35% by weight, of units of an ethylenically unsaturated monomer, preferably of acrylonitrile or methacrylonitrile, in particular of acrylonitrile.
The graft A2 here is composed of at least one graft shell, and the overall graft copolymer A has a median particle size of from 50 to 1000 nm.
In one embodiment of the invention, component A1 is composed of the following monomers:
a11: as component A11, from 80 to 99.99% by weight, preferably from 95 to 99.9% by weight, of a C
1
-C
8
-alkyl acrylate, preferably n-butyl acrylate and/or ethylhexyl acrylate, and
a12: as component A12, from 0.01 to 20% by weight, preferably from 0.1 to 5.0% by weight, of at least one polyfunctional crosslinking monomer, preferably diallyl phthalate and/or DCPA.
In one embodiment of the invention the median particle size of component A is from 50 to 800 nm, preferably from 50 to 600 nm.
In another embodiment of the invention, the particle size distribution of component A is bimodal, where, based on the total weight of component A, from 60 to 90% by weight has a median particle size of from 50 to 200 nm and from 10 to 40% by weight has a median particle size of from 50 to 400 nm.
The median particle size and particle size distribution given are the sizes determined from the integral mass distribution. The median particle sizes according to the invention are in all cases the weight average of the particle sizes. The determination of these is based on the method of W. Scholtan and H. Lange, Kolloid-Z. and Z.-Polymere 250 (1972), pages 782-796, using an analytical ultracentrifuge. The ultracentrifuge measurement gives the integral mass distribution of the particle diameter of a specimen. From this it is possible to deduce what percentage by weight of the particles have a diameter identical to or smaller than a particular size. The median particle diameter, which is also termed the d
50
of the integral mass distribution, is defined here as the particle diameter at which 50% by weight of the particles have a diameter smaller than that corresponding to the d
50
. Equally, 50% by weight of the particles then have a larger diameter than the d
50
. To describe the breadth of the particle size distribution of the rubber particles, d
10
and d
90
values given by the integral mass distribution are utilized alongside the d
50
value (median particle diameter). The d
10
and d
90
of the integral mass distribution are defined similarly to the d
50
with the difference that they are based on, respectively, 10 and 90% by weight of the particles. The quotient
d
90
-
d
10
d
50
=
Q
is a measure of the breadth of the particle size distribution. Emulsion polymers A which can be used according to the invention as component A preferably have Q less than 0.5, in particular less than 0.35.
The glass transition temperature of the emulsion polymer A, and also of the other components used according to the invention, is determined using DSC (differential scanning calorimetry) in accordance with ASTM 3418 (midpoint temperature).
The rubbers which can be used as emulsion polymer A are the usual relevant rubbers such as, in one embodiment of the invention, epichlorohydrin rubbers, ethylene-vinyl acetate rubbers, polyethylene chlorosulfone rubbers, silicone rubbers, polyether rubbers, hydrogenated
Bernstorff Bernd-Steffen von
Brandstetter Franz
Endemann Ulrich
McKee Graham Edmund
Naarmann Herbert
BASF - Aktiengesellschaft
Keil & Weinkauf
Michl Paul R.
LandOfFree
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