Stock material or miscellaneous articles – Hollow or container type article – Glass – ceramic – or sintered – fused – fired – or calcined metal...
Reexamination Certificate
2001-06-22
2003-06-17
Woodward, Ana (Department: 1711)
Stock material or miscellaneous articles
Hollow or container type article
Glass, ceramic, or sintered, fused, fired, or calcined metal...
C428S035700, C428S475500, C525S066000, C525S179000, C524S514000
Reexamination Certificate
active
06579581
ABSTRACT:
CROSS REFERENCES TO RELATED APPLICATIONS
This application claims priority to German Patent Application No. 10030716.7, filed on Jun. 23, 2000, and which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a material having good low-temperature impact strength and comprising, besides polyamide (PA) as matrix polymer, at least two other polymers which act synergistically to improve the impact strength of the material. The present invention further relates to moldings made from this material.
2. Discussion of the Background
Engineering components such as those used in the automotive industry sector, for example fuel lines which are tubes having one or more layers, nowadays have to fulfill very strict requirements with respect to low-temperature impact strength. To this end, tests are carried out using a variety of methods at a test temperature of −40° C., for example.
It is known that when plasticizers are added to the polyamides frequently used for engineering components of this type, e.g. nylon-4,6; nylon-6,6; nylon-4,12; nylon-6,12; nylon-6; nylon-11; or nylon-12, the materials have poor low-temperature impact strength and it is therefore essential that these materials are modified appropriately.
WO 95/22579 describes the impact-modification of polyamides using two impact modifiers, one modifier used being a modified EPM rubber or a modified EPDM rubber, while the other modifier used is a terpolymer made from ethylene and from an acrylic ester and glycidyl (meth)acrylate. This publication says nothing about the amino end group content of the polyamide. This is not surprising, since even if there is a considerable deficit of amino end groups, the bonding achieved between maleic-anhydride-functionalized EPM rubber or maleic-anhydride-functionalized EPDM rubber and polyamide is normally good.
The use of similar molding compositions as materials for layers in tubes having two or more layers has been described in EP-A-O 731 308, where again nothing is said about the amino end group content of the polyamide.
SUMMARY OF THE INVENTION
Accordingly, it is one object of the present invention to provide molding compositions and, respectively, moldings with particularly high low-temperature impact strength.
It is another object of the present invention to provide molding compositions and, respectively, moldings with good low-temperature impact strength but with the lowest possible content of impact modifiers, so that there is the smallest possible effect on other important properties.
It is another object of the present invention to provide a means of counteracting the effect of the plasticizer, which reduces low-temperature impact strength in plasticized polyamide molding compositions.
These and other objects, which will become apparent during the following detailed description, have been achieved by means of a molding composition which comprises the following components:
(I) from 60 to 96.5 parts by weight of polyamide;
(II) from 3 to 39.5 parts by weight of an impact-modifying component which comprises anhydride groups, where the impact-modifying component is selected from the group consisting of ethylene/&agr;-olefin copolymers and styrene-ethylene/butylene block copolymers; and
(III) from 0.5 to 20 parts by weight of a copolymer which comprises monomer units of the following monomers:
(a) from 20 to 94.5% by weight, based on the total weight of (a), (b), and (c), of one or more &agr;-olefins having from 2 to 12 carbon atoms,
(b) from 5 to 79.5% by weight, based on the total weight of (a), (b), and (c), of one or more acrylic compounds, selected from the group consisting of:
(i) acrylic acid and methacrylic acid and salts thereof;
(ii) esters of acrylic acid and/or of methacrylic acid with a C
1
-C
12
alcohol, said esters optionally bearing a free hydroxyl or epoxide function;
(iii) acrylonitrile and methacrylonitrile; and
(iv) acrylamides and methacrylamides; and
(c) from 0.5 to 50% by weight, based on the total weight of (a), (b), and (c), of an olefinically unsaturated epoxide, carboxylic anhydride, carboximide, oxazoline or oxazinone,
wherein the total of the parts by weight of components I, II, and III is 100, and wherein the polyamide has more amino end groups than carboxyl end groups.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Thus, in a first embodiment, the present invention provides molding compositions which comprise:
(I) from 60 to 96.5 parts by weight of polyamide;
(II) from 3 to 39.5 parts by weight of an impact-modifying component which comprises anhydride groups, where the impact-modifying component is selected from the group consisting of ethylene/&agr;-olefin copolymers and styrene-ethylene/butylene block copolymers; and
(III) from 0.5 to 20 parts by weight of a copolymer which comprises monomer units of the following monomers:
(a) from 20 to 94.5% by weight, based on the total weight of (a), (b), and (c), of one or more &agr;-olefins having from 2 to 12 carbon atoms,
(b) from 5 to 79.5% by weight, based on the total weight of (a), (b), and (c), of one or more acrylic compounds, selected from the group consisting of:
(i) acrylic acid and methacrylic acid and salts thereof;
(ii) esters of acrylic acid and/or of methacrylic acid with a C
1
-C
12
alcohol, said esters optionally bearing a free hydroxyl or epoxide function;
(iii) acrylonitrile and methacrylonitrile; and
(iv) acrylamides and methacrylamides; and
(c) from 0.5 to 50% by weight, based on the total weight of (a), (b), and (c), of an olefinically unsaturated epoxide, carboxylic anhydride, carboximide, oxazoline or oxazinone,
wherein the total of the parts by weight of components I, II, and III is 100, and wherein the polyamide has more amino end groups than carboxyl end groups.
In preferred embodiments, the present molding composition comprises:
(I) from 65 to 90 parts by weight, particularly preferably from 70 to 85 parts by weight, of the polyamide;
(II) from 5 to 30 parts by weight, particularly preferably from 6 to 25 parts by weight, and more particularly preferably from 7 to 20 parts by weight, of the impact-modifying component; and
(III) from 0.6 to 15 parts by weight, and particularly preferably from 0.7 to 10 parts by weight, of the copolymer, which preferably comprises monomer units of the following monomers:
(a) from 30 to 80% by weight, based on the total weight of (a), (b), and (c), of &agr;-olefin(s);
(b) from 7 to 70% by weight, particularly preferably from 10 to 60% by weight, based on the total weight of (a), (b), and (c), of the acrylic compound(s): and
(c) from 1 to 40% by weight, particularly preferably from 5 to 30% by weight, based on the total weight of (a), (b), and (c), of the olefinically unsaturated epoxide, carboxylic anhydride, carboximide, oxazoline, or oxazinone.
Polyamides which may be used are mainly aliphatic homo- or copolycondensates, such as nylon-4,6; nylon-6,6; nylon-6,8; nylon-6,10; nylon-6,12; nylon-4,10; nylon-8,10; nylon-10,10; nylon-4,12; nylon-10,12; nylon-12,12; nylon-6; nylon-7; nylon-8; nylon-9; nylon-10; nylon-11; and nylon-12. (The naming of the polyamides corresponds to an international standard according to which the first numeral(s) give(s) the number of carbon atoms in the starting diamine, and the final numeral(s) give(s) the number of carbon atoms in the dicarboxylic acid. If only one numeral is mentioned, that means that the starting material was an &agr;,&ohgr;-aminocarboxylic acid or the lactam derived therefrom. Reference may also be made to H. Domininghaus,
Die Kunststoffe und ihre Eigenschaften [Plastics and their properties],
pp. 272 et seq. VDI-Verlag, 1976, which is incorporated herein by reference).
If use is made of copolyamides, these may contain adipic acid, sebacic acid, suberic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid, for example, as coacid and, respectively, bis(4-aminocyclohexyl)methane, trimethylhexamethylenediamine, hexamethylenediamine or the like as codiamine. Lactams, such as caprolact
Bartz Wilfried
Baumann Franz-Erich
Haeger Harald
Oenbrink Georg
Schmitz Guido
Degussa - AG
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Woodward Ana
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