Blends of cycloolefin and core/shell polymers

Details Blends of cycloolefin and core/shell polymers Blends of cycloolefin and core/shell polymers

1997-11-10

2003-07-22

Niland, Patrick D. (Department: 1714)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

C525S064000, C525S075000, C525S210000, C525S211000, C525S902000

Reexamination Certificate

active

06596810

ABSTRACT:

The present invention relates to polymer alloys of cycloolefin copolymers (COC) and core/shell particles. The polymer alloys (mixtures) according to the invention are impact-resistant and are distinguished by a high flexural strength, elongation at break and improved processibility.
Impact-resistant polymers are sufficiently known and are suitable for a large number of applications (C. B. Bucknall, Toughened Plastics, Applied Science Publishers, London 1977; A. E. Platt, Rubber Modification of Plastics, Advances in Polymer Science, page 437).
It is furthermore known that the impact strength and the elongation at break of polymers can be improved by alloying. Thus, the impact strength of brittle polymers can be improved by alloying with polymer systems which are built up completely or partly or rubbers having low glass transition temperatures. However, this has the disadvantage that the morphology and therefore also the mechanical properties depend sensitively on the processing conditions (Polymer News, Vol. 16 (1991), page 198-206; A. E. Platt, Rubber Modification of Plastics, Advances in Polymer Science, page 437; P. A. Lovell et al., Polymer, 34 (1993) page 61).
In order to avoid this disadvantage, core/shell particles have been proposed for impact modification (Res. Discl. 323, pages 925-926; P. A. Lovell et al., Polymer 34 (1993) page 61; M. Lu et al., Polymer, 34 (1993) page 1874; C. B. Bucknall, Rubber-modified Plastics, Comprehensive Polymer Science, Pergamon Press (1989), page 27-49). These are used as impact modifiers, for example for PVC or PMMA (Gächter/Müller Kunststoff-Additive [Plastics Additives] XXIX; Carl Hanser, Munich, 1983 and C. B. Bucknall, Rubber-modified Plastics, Comprehensive Polymer Science, Pergamon Press (1989), page 27-49). However, since the mechanical properties of impact-modified polymers cannot be predicted additively from the properties of the individual components (D. R. Paul et al. in Encyclopedia of Polymer Science, Volume 12, 1984), impact modification of polymers is a largely empirical task. This means that core/shell particles have to be specifically tailor-made in expensive optimization tests for each polymer of which the impact strength is to be modified and for each application (J. Oshiima, Seni Gakkaishi, 48(5) (1992) page 274; M. Lu et al., Polymer, 34 (1993) page 1874). Commercially obtainable core/shell particles accordingly are in each case suitable only for quite specific polymers and applications.
An essentially prerequisite for achieving adequate impact strengths is good phase adhesion or miscibility between the matrix polymer and the rubber-containing polymer (D. R. Paul in Encyclopedia of Polymer Science Volume 12 (1984) page 437; A. E. Platt in Comprehensive Polymer Science, Pergamon Press N.Y. (1989) page 437, C. B. Bucknall in Toughened Plastics, Applied Science Publishers, London (1977) pages 209-210; M. Lu et al., Polymer, 34 (1993) page 1874). Like all polyolefins, COC (EP 203 799, EP 283 164, EP 407 870, EP 485 893, EP 503 422, DD 222 317, DD 231 070, DD 246 903, EP 156 464) are also poorly miscible with other polymers and therefore have a poor phase adhesion to other polymers. According to D. W. van Krevelen (Properties of Polymers, Elsevier, Amsterdam-Oxford-New York, 1976, chapter 4), the compatibility and therefore the phase adhesion can be estimated via the solubility parameter delta, values of about 13.5 J
½
cm
3/2
being obtained. These values are significantly below those of typical impact-modifiable polymers.
For impact modification of COC, it has thus hitherto been necessary to crosslink these with the rubber-containing polymer (JP 92-170453, JP 92-170454, JP 356353).
The morphologies and degrees of crosslinking and the associated impact strength and rheological properties can be established reliably and reproducibly by this procedure only with difficulty. In particular, the reproducibility of the properties mentioned depends sensitively on parameters such as, for example, processing conditions, crosslinking agent content, temperature and time.
The object was thus to provide an impact-resistant polymer which avoids the disadvantages of the prior art.
Surprisingly, it has now been found that polymer alloys of COC and core/shell particles are impact-resistant and have a good flexural strength. Furthermore, COC can be impactmodified with a large number of widely diverse core/shell particles without the particles having to be optimized in an expensive manner for the polymer and the particular application. Furthermore, the polymer alloys can be processed in an industrially simple manner.
The present invention thus relates to a polymer alloy which comprises a) one or more cycloolefin copolymers and b) one or more types of core/shell particles.
The polymer alloy according to the invention preferably comprises one COC and one or more types of core/shell particles, particularly preferably one COC and one type of core/shell particles.
The COC which are suitable for the purposes of the invention have glass transition temperatures of between 50 and 250° C., preferably between 100 and 200° C., particularly preferably between 100 and 150° C.
The polymer alloy (mixtures) according to the invention preferably comprises COC which comprise 0.1 to 99% by weight of structural units which are derived from polycyclic olefins, based on the total weight of the COC, preferably radical such as a linear or branched C
1
-C
8
-alkyl radical, a C
6
-C
18
-aryl radical, a C
7
-C
20
-alkylenearyl radical or a cyclic or acyclic C
2
-C
10
-alkenyl radical, or two or more radicals R
1
to R
8
form a ring, and the radicals R
1
to R
8
in the various formulae I to VI can have a different meaning,
0 to 95% by weight of structural units, based on the total weight of the COC, which are derived from one or more monocyclic olefins, preferably of the formula VII
 in which n is a number from 2 to 10, and
0 to 99% by weight of structural units, based on the total weight of the COC, which are derived from one or more acyclic olefins, preferably of the formula VIII
 in which R
9
, R
10
, R
11
and R
12
are identical or different and are a hydrogen atom or a C
1
-C
20
hydrocarbon radical such as C
1
-C
8
-alkyl radical or C
6
-C
12
-aryl radical.
The cycloolefin copolymers preferably comprise structural units which are derived from one or more cyclic olefins, particularly preferably polycyclic olefins of the formulae I or III, and one or more acyclic olefins preferably of the formula VIII, in particular &agr;-olefins having 2 to 20 carbon atoms. Cycloolefin copolymers which comprise structural units which are derived from a polycyclic olefin of the formula I or III and an acyclic olefin of the formula VIII are particularly preferred.
Preferred COC are those which comprise structural units of the formulae I, II, III, IV, V or VI,
in which R
1
, R
2
, R
3
, R
4
, R
5
, R
6
, R
7
and R
8
are identical or different and are a hydrogen atom or a C
1
-C
20
hydrocarbon which are derived from polycyclic olefins having a norbornene base structure, particularly preferably norbornene or tetracyclododecene. Preferred COC are also those which comprise structural units which are derived from acyclic olefins having terminal double bonds, such as &agr;-olefins, particularly preferably ethylene or propylene. Norbornene/ethylene and tetracyclododecene/ethylene copolymers are particularly preferred. The content of acyclic olefins preferably of the formula VIII is 0 to 99% by weight, preferably 5 to 80% by weight, particularly preferably 10 to 60% by weight, based on the total weight of the COC.
The COC are prepared at temperatures of −78 to 150° C. Under a pressure of 0.01 to 64 bar, in the presence of one or more catalysts, which comprise a transition metal compound and, if appropriate, a cocatalyst. Suitable transition metal compounds are metallocenes, especially stereorigid metallocenes, and compounds based on titanium and vanadium. Examples of catalyst systems appropriate to the preparation of the COC suitable for the purposes

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