Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1997-05-12
1998-11-17
Lipman, Bernard
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
515308, 5153303, 515387, C08F 800
Patent
active
058377778
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for the preparation of rubber-modified molding materials, in particular acrylonitrile/styrene/acrylate molding materials, in which a compound which contains peroxy groups is used, and to rubber-modified molding materials prepared by the process.
Rubber-modified molding materials are materials in which domains of elastomers, for example rubbers, are embedded in a matrix comprising a thermoplastic. There is considerable demand for rubber-modified molding materials which have surface gloss, impact strength and tensile strength. The characteristic domain structure is responsible for the desired mechanical properties.
The multiphase character and hence also the domain structure of rubber-modified molding materials is based on the fact that they are composed of different polymer components which are immiscible or only partly miscible with one another. The impact strength thereof results from increased energy absorption during deformation up to fracture. The energy is consumed for the formation of microcavities or for initiating sliding processes of the matrix polymer chains. The multiphase character is therefore essential for achieving high impact strengths.
The following are applicable below: of defined particle size, which neither exhibits phase separation in the thermoplastic melt (processing) nor tends to homogenization with formation of a macromolecular solution at high temperatures. it must be possible to transmit forces at the phase boundaries.
The most effective phase coupling at the boundaries of the elastomer particles is achieved by graft copolymerization. For example, in the preparation of acrylonitrile/styrol/acrylate (ASA) molding materials, the procedure generally adopted is one in which an acrylate rubber is initially taken and, by polymerization with a monomer mixture comprising styrol and acrylonitrile, copolymers based on the latter two monomers are then grafted on.
EP 0 095 919, DE 1 182 811, JA 7103 182, JA 60 21 0666, EP 0 143 991, EP 0 438 418 and B. Vollmert, Angewandte Makromolekulare Chemie, 3 (1968), 1-27, described the preparation of thermoplastics modified with acrylate rubber.
Starting from this, it is an object of the present invention to provide a process for the preparation of rubber-modified molding materials having improved mechanical properties, in particular higher impact strength and notched impact strength.
We have found that this object is achieved by the novel process, in which, in a first stage, a first mixture (A) which contains at least one alkyl acrylate or methacrylate (a) of the general formula (I) ##STR2## where R.sup.1 is hydrogen or methyl and R.sup.2 is alkyl of 1 to 32 carbon atoms, if required a first monomer (b) having two or more double bonds and, if required, a second monomer (c) or a plurality thereof is polymerized, preferably in solution, preferably with free radicals, to give a rubber (B), in a second stage, a third monomer (d) or a plurality thereof is added to the resulting rubber (B) to form a second mixture (C), and in a third stage, the second mixture (C) formed after dissolution or swelling is polymerized with free radicals to give the rubber-modified molding material (D).
In the second stage, the rubber (B), with or without the addition of a solvent, is preferably dissolved or swollen in the third monomer (c).
A graft copolymerization takes place in the third stage, the backbone of the resulting graft copolymer being formed by the rubber (B), and the grafts being composed of the third monomer (d). Because 100% grafting does not occur, some of the rubber remains ungrafted and at the same time a chain polymer is formed from the third monomer (d), so that three types of molecules are present in the molding material, ie. molecules of the rubber (B), of the polymer of (d) and of the rubber (B) grafted with (d).
During or after the polymerization of the third stage, the batch is treated at >120.degree. C. with a compound (e) which contains at least two peroxy groups. The compound (e) may be added at any tim
REFERENCES:
patent: 4342676 (1982-08-01), Ivanchev et al.
patent: 4397992 (1983-08-01), Johansson et al.
patent: 5367029 (1994-11-01), Fischer et al.
Vollmert et al., App. Macrom. Chem., No. 3, 1968, pp. 1-27.
Heckmann Walter
Larbig Harald
McKee Graham Edmund
Moors Rainer
Rosenau Bernhard
BASF - Aktiengesellschaft
Lipman Bernard
LandOfFree
Preparation of rubber-modified molding materials using peroxy-co does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Preparation of rubber-modified molding materials using peroxy-co, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Preparation of rubber-modified molding materials using peroxy-co will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-885087