Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2001-12-19
2004-02-10
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S063000, C525S069000, C525S230000, C525S233000
Reexamination Certificate
active
06689838
ABSTRACT:
The invention relates to molding compositions, moldings, products, recycled materials, and also laminates, and to the use of these.
Moldings made from polymeric materials and used in particular in the interior of motor vehicles have to meet high requirements, especially in relation to their mechanical properties, their surface properties, their aging performance, and also their emission performance or odor performance. Various polymeric materials have been used hitherto for producing moldings for automotive construction and automotive interior applications.
One material used is ABS. This material has poor UV resistance, poor heat-aging resistance and poor heat resistance (Vicat B softening point <110° C.).
Another material used is ABS/PC (a polymer blend made from acrylonitrile/butadiene/styrene copolymer and polycarbonate). However, this material has inadequate UV resistance, poor heat-aging performance (toughness and elongation at break after heat-aging), poor environmental stress cracking resistance, for example with respect to plasticizer, poor flowability, and also in particular poor emission properties and poor odor performance. For the purposes of the present invention, odor performance is the tendency of materials to release volatile constituents with detectable odor after the material has been stored for a specified time under particular conditions of temperature and of humidity.
Another material used is ABS/PA (a polymer blend made from ABS and polyamide). ABS/PA, too, has poor UV resistance, poor heat resistance (Vicat B softening point <110° C.), poor heat-aging resistance, poor dimensional stability due to high moisture absorption, and also poor flowability.
Another material used is PPE/HIPS (a polymer blend made from polyphenylene oxide and impact-modified polystyrene). Disadvantages of this material are poor flowability, poor UV resistance, foam adhesion and heat-aging resistance, and also its poor odor performance.
Use is also made of PET/PC (a polymer blend made from polyethylene terephthalate and polycarbonate). Disadvantages of this material are poor environmental stress cracking resistance, for example with respect to plasticizers, and also its poor flowability.
Another material used is PBT/PC, which has poor flowability and environmental stress cracking resistance.
Most of the abovementioned materials have poor heat resistance, expressed in terms of a low Vicat B softening point (Vicat B <130° C.), and also poor heat-aging resistance. However, good heat resistance and heat-aging resistance are essential in the materials used, since the interior of a motor vehicle can be subject to considerable heating, in particular when exposed to insolation.
The materials currently available also have shortcomings for external applications. For example, blends made from PPE and PA have poor dimensional stability due to moisture absorption, and poor processibility.
It has been possible to remove the abovementioned disadvantages using polymeric materials based on PBT/ASA/PSAN (polymer blends made from polybutylene terephthalate, acrylonitrile/styrene/acrylate copolymer and polystyrene/acrylonitrile copolymer). A general disclosure of materials of this type is made in DE-A 39 11 828. The examples relate to molding compositions with high acrylonitrile content in the PSAN copolymers. However, moldings made from these molding compositions, like the majority of the abovementioned materials, have poor emission performance and odor performance.
In addition, when processed by injection molding these polymeric materials have disadvantages. Freshly produced injection moldings have relatively high adhesion to the mold walls, for example due to incomplete crystallization. This relatively high adhesion makes it necessary to provide the surfaces of the injection molds with appropriate adhesion-reducing agents, in order to avoid unnecessary prolongation of the cycle times for the individual injection-molding procedures as a result of the tendency of the molding composition to adhere. Another way of keeping the cycle time very low is to admix adhesion-reducing agents with the molding composition itself. However, the use of adhesion-reducing agents either in the injection mold, or else in the molding composition itself, mostly causes undesirable deposits on the surface of the injection mold, and these have, for example, an adverse effect on the surface of the molding. The cycle time is defined as the period from injection of the melt of the molding composition to demolding of the injection molding. The cycle time has a direct effect on the number of units produced on each injection molding plant, and therefore on the cost of the injection molding. It is, of course, possible to reduce the tendency of the molding composition to adhere by cooling the injection molds. However, this is firstly attended by high technical costs and secondly means that cooling has to be repeated for each cycle, and over a large number of cycles the attendant temperature variations bring about relatively rapid materials fatigue in the injection mold, which then has to be replaced more frequently.
It is an object of the present invention to provide molding compositions suitable for producing moldings Which are used in the interior of motor vehicles and for exterior body parts and have an advantageous property profile with respect to their mechanical, optical and surface properties, and also in particular have good heat resistance and heat-aging resistance and good emission performance and/or odor performance. The molding compositions should also have very low density. The low density is particularly advantageous with regard to fuel saving in motor vehicles. The moldings should also be easy to recycle. A further object is to reduce the adhesion of the molding compositions in injection molding and to avoid any impairment of the other properties as a result of this reduction. A further object is that there should be very little need to cool the surface of the injection mold in order to remove the molding from the mold. A further object is that the amount of adhesion-reducing agent used on the surface of the injection mold and, respectively, in the molding composition should be kept very low, especially so that no deposits of this adhesion-reducing agent develop on the surface of the injection mold.
We have found that this object is achieved by a molding composition comprising, based on the total of components A to G, which is 100% by weight,
a) as component A of the molding composition, from 1 to 99.59% by weight of at least one polycondensate,
b) as component B, from 0.1 to 20% by weight of at least one particulate graft copolymer with a glass transition temperature of the soft phase below 0° C. and with a median particle size of from 50 to 1000 nm,
c) as component C, from 0.1 to 20% by weight of at least one copolymer. made from the following monomers
c1) as component C1, from 50 to 90% by weight of at least one vinylaromatic monomer, and
c2) as component C2, from 10 to 50% by weight of acrylonitrile and/or methacrylonitrile, in each case based on component C,
d) as component D, from 0 to 20% by weight of a copolymer similar to component C, where the content in % by weight of acrylonitrile and/or methacrylonitrile in component C differs from that in component D,
e) as component E, from 0.1 to 20% by weight of a polyester other than component A,
f) as component F, from 0.01 to 10% by weight of at least one nucleating agent and of at least one transesterification stabilizer, where the ratio by weight of nucleating agent to transesterification stabilizer is from 1:100 to 100:1, preferably from 1:10 to 10:1 and particularly preferably from 1:3 to 3:1, and
g) as component G, from 0.1 to 10% by weight of customary additives, such as carbon black, UV stabilizers, oxidation retarders, lubricants and mold-release agents.
Each of the components differs from the others and is described in detail below.
The novel molding composition comprises, as complementary constituent component A, up to 99.59% by weight based on th
Fischer Michael
Rau Walter
Asinovsky Olga
BASF - Aktiengesellschaft
Keil & Weinkauf
Seidleck James J.
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