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
2001-08-09
2003-03-11
Mullis, Jeffrey (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...
C525S071000, C525S085000, C525S086000
Reexamination Certificate
active
06531543
ABSTRACT:
The invention relates to thermoplastic molding compositions based on ASA (acrylonitrile-styrene-acrylate) and having improved flowability and improved extrusion properties. The invention further relates to a process for preparing these thermoplastic molding compositions and to their use, and also to films and moldings produced therefrom and to the use of these.
There is a wide variety of application sectors for thermoplastic molding compositions, and there is therefore a variety of known molding compositions with differing mixes for different application sectors.
EP-A 0 526 813 describes polymer blends for flexible films. These are made from a graft copolymer of vinyl monomers as graft shell on an acrylate rubber as graft base, a partially crosslinked copolymer rubber based on acrylate, an uncrosslinked polymer based on styrene compounds and/or on acrylic compounds and an ethylene-vinyl acetate copolymer. The plastic material which can be obtained, in which no PVC is present, is suitable for producing leather-like films. However, under molding conditions, to give films for example, these compositions tend to discolor undesirably. Films of this type also exhibit relatively severe fogging when processed by methods similar to those conventionally used.
DE-A 42 11 482 describes a surface film having one or more layers and made from a thermoplastic with good surface tension and good notch impact strength. The film has a very low level stress whitening. The “hard” component of the thermoplastic is a styrene-acrylonitrile (SAN) copolymer, and the “softer” component is an elastomer-modified styrene copolymer, in particular a rubber-grafted SAN copolymer. There may also be high-molecular-weight acrylates or acrylate copolymers present. This base film has an outer layer, for example made from polyacrylate, PVDF film, PVF film, polycarbonate film or polyester film. Conventional additives may also be present. However, the process to prepare graft polymers of this type is complicated, and it is therefore difficult to obtain consistent product quality. Nothing is said about the flow behavior of these molding compositions.
EP-A 0 693 530 describes impact-modified molding compositions based on polyisobutylene-containing polycarbonate. These molding compositions comprise an aromatic polycarbonate modified with polyisobutylene, a graft copolymer which has a core based on diene and/or on acrylate, and a shell made from styrene and acrylonitrile, for example, and, where appropriate, comprise another rubber and copolymer, and also, where appropriate, aromatic polycarbonate and polyolefins. The function of the polyisobutylene in these molding compositions is to provide molding compositions with particular high impact strength.
DE-A 20 20 478 teaches that polyisobutylene (=polyisobutene) improves the dielectric properties of molding compositions made from blends of thermoplastics.
The Amoco company publication “Amoco polybutenes”, published in 1994, describes the properties of “Amoco polybutenes”, isobutylene-butene copolymers whose precise makeup is not disclosed. Page 18 generally describes an improvement in the impact strength, elasticity and melt flow rate of a wide variety of thermoplastics.
The Amoco company publication “Acrylonitrile-butadiene-styrene modification using Amoco polybutenes” of June 1995 describes the use of the “Amoco polybutenes” mentioned in ABS and the effect on impact strength, flow rate, tensile strength and HDT (heat resistance) of adding “Amoco polybutene”. This company publication relates exclusively to ABS (acrylonitrile-butadiene-styrene) polymers and to the effect of “Amoco polybutene” on the properties of these polymers. No indication can be found in this company publication of the extrusion properties of ABS polymers modified with “Amoco polybutenes”.
EP-A 0 675 164 discloses thermoplastic molding compositions made from a graft copolymer and from a copolymer and, where appropriate, from a thermoplastic polymer, preferably SAN (styrene-acrylonitrile). These may readily be rolled to give films. However, flowability is too low for extrusion applications, in particular to give soft, reduced-gloss films.
The application with file reference number DE 198 17 218, which is not a prior publication, describes thermoplastic molding compositions which comprise a graft copolymer, a thermoplastic polymer, preferably SAN, and another copolymer made from styrene and/or &agr;-methylstyrene, butadiene and, where appropriate, from one or more other monomers whose double bonds have been almost completely hydrogenated. To improve flowability, these thermoplastic molding compositions comprise isobutene or an isobutene copolymer. However, these molding compositions are not matt.
It is an object of the present invention, therefore, to provide molding compositions based on the thermoplastic molding compositions disclosed in DE 198 17 218 and having particularly good flowability and good extrusion properties and capable of reliable extrusion to give films or moldings with a soft, matt surface, with consistent product quality. A further object was to provide a process for preparing these thermoplastic molding compositions, and also the use of the molding compositions of the invention for producing moldings or films, or as coextrusion compositions.
Other objects are to provide films and moldings made from the molding compositions of the invention which have good and balanced mechanical properties, and the use of these.
We have found that this object is achieved, as are the other objects described, by way of thermoplastic molding compositions, essentially comprising
(A) from 20 to 99% by weight of at least one graft copolymer, essentially obtainable from
(a1) from 30 to 90% by weight of a core, obtainable by polymerizing a monomer mixture, essentially consisting of
(a11) from 80 to 99.99% by weight of at least one C
1
-C
10
-alkyl acrylate,
(a12) from 0.01 to 20% by weight of at least one copolymerizable, polyfunctional, crosslinking monomer, and
(a13) from 0 to 40% by weight, based on the total weight of components (a11) and (a12), of at least one other copolymerizable, monoethylenically unsaturated monomer, and
(a2) from 10 to 70% by weight of a graft shell, obtainable by polymerizing a monomer mixture in the presence of the core (a1), and essentially consisting of
(a21) from 50 to 100% by weight of at least one styrene compound of the formula (I)
where R
1
and R
2
, independently of one another, are hydrogen or C
1
-C
8
-alkyl and/or of a C
1
-C
8
-alkyl (meth)acrylate, and
(a22) from 0 to 50% by weight of at least one monofunctional comonomer, and
(B) from 1 to 80% by weight of a copolymer obtainable from at least one alpha-olefin and from at least one polar comonomer, with the proviso that the monomers used are not vinyl acetate or any vinylaromatic monomer, and
(C) from 0 to 80% by weight of a thermoplastic polymer, obtainable by polymerizing a monomer mixture, essentially consisting of
(c1) from 50 to 100% by weight of at least one vinylaromatic monomer and/or of a C
1
-C
8
-alkyl (meth)acrylate, and
(c2) from 0 to 50% by weight of at least one monofunctional comonomer, and
(D) from 0.5 to 30% by weight of a (co)polymer made from
(d1) from 50 to 100% by weight of isobutene and
(d2) from 0 to 50% by weight of one or more other monomers,
where the overall total of components A to D is 100% by weight.
These molding compositions have excellent flowability and very good extrusion properties. They can be processed to give films or moldings with a soft, matt surface, with consistent product quality. The molding compositions of the invention are also suitable as soft coextrusion compositions with good flowability and reduced gloss.
The amount of component (A) present in the molding compositions of the invention, based on the total of components (A) to (D), is from 20 to 99% by weight, preferably from 30 to 98% by weight and particularly preferably from 50 to 95% by weight. This component is a particulate graft copolymer built up from an elastomeric graft core (a1) (“soft compone
Güntherberg Norbert
Lindenschmidt Gerhard
Rath Hans Peter
Weber Martin
BASF - Aktiengesellschaft
Keil & Weinkauf
Mullis Jeffrey
LandOfFree
Thermoplastic molding compositions based on... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermoplastic molding compositions based on..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermoplastic molding compositions based on... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3074166