Polymer blend

The present invention relates to a polymer blend comprising one or more cycloolefin copolymers and one or more types of core-shell particles or one or more copolymers which are composed to some extent of rubbers with low glass transition temperatures, or a combination of one or more types of core-shell particles and of one or more copolymers which are composed to some extent of rubbers with low glass transition temperatures.

The present invention relates to polymer blends made from cycloolefin
 copolymers (COC) and from impact modifiers. The novel polymer blends are
 impact-resistant and have high flexural strength and elongation at break,
 and improved processability.
 Impact-modified polymers are well known and are suitable for a wide variety
 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 also known that the impact resistance and the elongation at break of
 polymers can be improved by blending. For example, the impact resistance
 of brittle polymers can be improved by blending with polymer systems which
 are composed entirely or partially of rubbers with low glass transition
 temperatures, or by blending with core-shell particles, or by combining
 these modifiers. The morphologies obtained here, and therefore also the
 mechanical properties, are highly dependent on the processing conditions
 used (G. H. Michler, Kunststoff-Mikromechanik [Micromechanics of
 Plastics], Hanser, Munich 1992, page 281 et seq.; A. E. Platt, Rubber
 Modification of Plastics, Advances in Polymer Science, page 437; P. A.
 Lovell et al., Polymer, 34 (1993), page 61).
 Polymer blends of cycloolefin copolymers are also known. EP-A-0 647 677 and
 EP-A-0 647 676 describe blends with core-shell particles. EP-A-0 661 345
 combines core-shell particles with copolymers which are composed to some
 extent of rubbers with low glass transition temperatures.
 PCT 97/46617 describes polymer blends of cycloolefin copolymers with
 copolymers which are composed to some extent of rubbers with low glass
 transition temperatures.
 The materials obtained by blending the cycloolefin copolymers described do
 not have the impact resistance required for industrial applications.
 The object of the present invention is to prepare a polymer with impact
 resistance sufficiently high for industrial applications.
 It has been found that a novel polymer blend which comprises one or more
 cycloolefin copolymers and
 a) one or more types of core-shell particles, or
 b) one or more copolymers which are composed to some extent of rubbers with
 low glass transition temperatures, or
 c) a combination of one or more types of core-shell particles and of one or
 more copolymers which are composed to some extent of rubbers with low
 glass transition temperatures
 has impact resistance which is sufficiently high for industrial
 applications.
 The novel polymer blend comprises at least one cycloolefin copolymer which
 is prepared by polymerizing from 0.1 to 99.9% by weight, based on the
 total amount of the monomers, of at least one polycyclic olefin of the
 formula I, II, II', III, IV or V
 ##STR1##
 where R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and
 R.sup.8 are identical or different and are a hydrogen atom or a
 hydrocarbon radical, where the same radicals in the different formulae may
 have a different meaning, and from 0 to 99.9% by weight, based on the
 total amount of the monomers, of at least one monocyclic olefin of the
 formula VI
 ##STR2##
 where n is a number from 2 to 10, and from 0.1 to 99% by weight, based on
 the total amount of the monomers, of at least one acyclic 1-olefin of the
 formula VlI
 ##STR3##
 where R.sup.9, R.sup.10, R.sup.11 and R.sup.12 are identical or different
 and are a hydrogen atom or a hydrocarbon radical, preferably a C.sub.6
 -C.sub.10 -aryl radical or a C.sub.1 -C.sub.8 alkyl radical.
 Preference is given to cycloolefins of the formulae I or III, where
 R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8
 are identical or different and are a hydrogen atom or a hydrocarbon
 radical, in particular a (C.sub.6 -C.sub.10)-aryl radical or a (C.sub.1
 -C.sub.8)-alkyl radical, where the same radicals in the different formulae
 may have a different meaning.
 If desired, the polymerization may use one or more monocyclic olefins of
 the formula VI.
 Preference is also given to an acyclic olefin of the formula VII, where
 R.sup.9, R.sup.10, R.sup.11 and R.sup.12 are identical or different and
 are a hydrogen atom or a hydrocarbon radical, preferably a C.sub.6
 -C.sub.10 -aryl radical or a C.sub.1 -C.sub.8 -alkyl radical, for example
 ethylene or propylene.
 The copolymers prepared are in particular those of polycyclic olefins,
 preferably of the formulae I and III, with ethylene.
 Particularly preferred polycyclic olefins are norbornene and
 tetracyclododecene, where these may have C.sub.1 -C.sub.6 -alkyl
 substitution. They are preferably copolymerized with ethylene. Very
 particular preference is given to ethylene-norbomene copolymers and
 ethylene-tetracyclododecene copolymers.
 The novel polymer blend is characterized in that the cycloolefin
 copolymer(s) present are prepared by the process described below. The
 process for preparing the cycloolefin copolymers present in the novel
 polymer blend is described in detail in DE-A-196 52 340, which is
 expressly incorporated herein by way of reference.
 The process according to the invention for preparing a cycloolefin
 copolymer encompasses the polymerization of from 0.1 to 99.9% by weight,
 based on the total amount of the monomers, of at least one polycyclic
 olefin, and from 0 to 99.9% by weight, based on the total amount of the
 monomers, of at least one monocyclic olefin, and from 0.1 to 99.9% by
 weight, based on the total amount of the monomers, of at least one acyclic
 1-olefin, in the presence of a catalyst system. The catalyst system to be
 used for preparing the cycloolefin copolymer present in the novel polymer
 blend comprises at least one transition metal compound. Preference is
 given to the use of one or more metallocenes as transition metal compound.
 The polymerization is carried out in the liquid cycloolefin itself or in a
 cycloolefin solution. The pressure is usefully above 1 bar.
 The catalyst system to be used in preparing the cycloolefin copolymer
 present in the novel polymer blend may moreover comprise one or more
 cocatalysts.
 The catalyst system to be used for preparing the cycloolefin copolymer
 present in the novel polymer blend is a high-activity catalyst for olefin
 polymerization. Preference is given to using a metallocene and a
 cocatalyst. It is also possible to use mixtures of two or more
 metallocenes, particularly for preparing reactor blends or polyolefins
 with a broad or multimodal molar mass distribution.
 The process for preparing the cycloolefin copolymer present in the novel
 polymer blend, and also the catalyst system to be used for this process,
 are described in detail in DE-A-1 96 52 340, which is expressly
 incorporated herein by way of reference.
 The cocatalyst present in the catalyst system to be used for preparing the
 cycloolefin copolymer present in the novel polymer blend preferably
 comprises an aluminoxane.
 Examples of the metallocenes to be used according to the invention are:
 isopropylene(1-indenyl)(3-methylcyclopentadienyl)zirconium dichloride,
 diphenylmethylene(1-indenyl)(3-methylcyclopentadienyl)zirconium dichloride,
 methylphenylmethylene(1-indenyl)(3-methylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(1-indenyl)(3-isopropylcyclopentadienyl)zirconium dichloride,
 diphenylmethylene(1-indenyl)(3-isopropylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3-isopropylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(1-indenyl)(3-tert-butylcyclopentadienyl)zirconium dichloride,
 diphenylmethylene(1-indenyl)(3-tert-butylcyclopentadienyl)zirconium
 dichloride
 methylphenylmethylene(1-indenyl)(3-tert-butylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(1-indenyl)(3-trimethylsilylcyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(3-trimethylsilylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3-trimethylsilylcyclopentadienyl)-zirconiu
 m dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-trimethylsilylcyclopentadienyl
 )-zirconium dichloride,
 diphenylmethylene(1-indenyl)(3-trimethylsilylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3-trimethylsilylpentadienyl)zirconium
 dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-trimethylsilylcyclopentadienyl
 )-zirconium dichloride;
 isopropylene(1-indenyl)(3,4-dimethylcyclopentadienyl)zirconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1
 -indenyl)(3-trimethylsiiyicyclopentadienyl)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-trimethylsilylcyclope
 ntadienyl)zirconium dichloride,
 isopropylene(1-indenyl)(3,4-di-trimethylsilylcyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(3,4-di-trimethylsiiylcyclopentadienyl)-zirconi
 um dichloride,
 methylphenylmethylene(1-indenyl)(3,4-di-trimethylsilylcyclopentadienyl)-zir
 conium dichloride,
 isopropylene(1-indenyl)(2,3-di-trimethylsiiylcyclopentadienyi)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(2,3-di-trimethylsilylcyclopentadienyl)-zirconi
 um dichloride,
 methylphenylmethyiene(1-indenyl)(2,3-di-trimethylsilylcyclopentadienyl)-zir
 conium dichloride,
 isopropylene(1-indenyl)(3,4-dimethyl(cyclopentadienyl)zirconium dichloride,
 diphenylmethylene( 1-indenyi)(3,4-dimethylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3,4-dimethyicyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(3,4-diethylcyclopentadienyi)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3,4-diethylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(1-indenyl)(3,4-diisopropylcyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(3,4-diisopropylcyclopentadienyl)zirconium
 dichioride,
 methylphenylmethylene(1-indenyl)(3,4-diisopropylcyclopentadienyl)-zirconium
 dichloride,
 isopropylene(1-indenyl)(3,4-diethylcyclopentadienyl)zirconium dichloride,
 isopropylene(1-indenyl)(3,4-di-tert-butylcyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(3,4-di-tert-butylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3,4-di-tert-butylcyclopentadienyl)-zirconi
 um dichloride,
 isopropylene(1-indenyl)(2,3-dimethyicyclopentadinyl)zirconium dichloride,
 diphenylmethylene(1-indenyl)(2,3-dimethylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(2,3-dimethylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(1-indenyl)(2,3-diethylcyclopentadienyl)zirconium dichloride,
 diphenylmethylene(1-indenyl)(2,3-diethylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(2,3-diethylcyclopentadienyi)zirconium
 dichloride,
 isopropylene(1-indenyl)(2,3-diisopropylcyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(2,3-diisopropylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(2,3-diisopropylcyclopentadienyl)-zirconium
 dichloride,
 isopropylene(1-indenyl)(2,3-di-tert-butylcyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(2,3-di-tert-butylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(2,3-di-tert-butylcyclopentadienyl)-zirconi
 um dichloride,
 isopropylene(1-indenyi)(tetramethylcyclopentadienyl)zirconium dichloride,
 diphenylmethylene(1-indenyl)(tetramethylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl) (tetramethylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-methylcyclopentadienyl)-zircon
 ium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-methylcyclopentadienyl)zi
 rconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-methylcyclopentadieny
 l)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-ethylcyclopentadienyl)-zirconi
 um dichloride, diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)
 (3-ethylcyclopentadienyl)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)
 (3-ethylcyclopentadienyl)zirconium dichloride,
 (isopropylcyclopentadienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-isopropylcyclopentadienyi)-zir
 conium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-isopropylcyclopentadienyl
 )zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)
 (3-isopropylcyclopentadienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-tert-butylcyclopentadienyl)-zi
 rconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-tert-butylcyclopentadieny
 l)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-tert-butylcyclopentad
 ienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-dimethylcyclopentadienyl)-zi
 rconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-dimethyicyclopentadieny
 l)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-dimethylcyclopentad
 ienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-diethylcyclopentadienyl)-zir
 conium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-diethylcyclopentadienyl
 )zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-diethylcyclopentadi
 enyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-diisopropylcyciopentadienyl)
 zirconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-diisopropylcyclopentadi
 enyl)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-diisopropylcyclopen
 tadienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-dibutylcyclopentadienyl)-zir
 conium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3,4-di-tert-butylcyclopenta
 dienyl)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)
 (3,4-di-tert-butyicyclopentadienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-dimethylcyclopentadienyl)-zi
 rconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-dimethylcyclopentadieny
 l)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-dimethylcyclopentad
 ienyl)zirconium dichioride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-methylcyclopentadienyl)zirco
 nium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-diethylcyclopentadienyl
 )zirconium dichloride,
 methylphenyimethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-diethylcyclopentadi
 enyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-diisopropylcyclopentadienyl)
 zirconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-diisopropylcyclopentadi
 enyl)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-diisopropylcyclopen
 tadienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-di-tert-butyicyclopentadieny
 l)-zirconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-di-tert-butylcyclopenta
 dienyl)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(2,3-di-tert-butylcyclop
 entadienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(tetramethylcyclopentadienyl)-zir
 conium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(tetramethylcyclopentadienyl
 )zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(tetramethylcyciopentadi
 enyl)zirconium dichloride.
 Particular preference is given to:
 isopropylene(1-indenyl)(3-isopropylcyclopentadienyl)zirconium dichloride,
 diphenyimethylene(1-indenyl)(3-isopropylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3-isopropylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(1-indenyl)(3-tert-butylcyclopentadienyl)zirconium dichloride,
 diphenylmethylene(1-indenyl)(3-tert-butylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3-tert-butylcyclopentadienyl)zirconium
 dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-isopropylcyclopentadienyl)-zir
 conium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-isopropylcyclopentadienyl
 )zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-isopropylcyclopentadi
 enyl)zirconium dichloride,
 isopropylene(1-indenyl)(3-trimethylsilylcyclopentadienyl)zirconium
 dichloride,
 diphenylmethylene(1-indenyl)(3-trimethylsilylcyclopentadienyl)zirconium
 dichloride,
 methylphenylmethylene(1-indenyl)(3-trimethylsilylcyclopentadienyl)-zirconiu
 m dichioride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-tert-butylcyclopentadienyl)-zi
 rconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-tert-butylcyclopentadieny
 l)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-tert-butylcyclopentad
 ienyl)zirconium dichloride,
 isopropylene(4,5,6,7-tetrahydro-1-indenyl)(3-trimethylsilylcyclopentadienyl
 )-zirconium dichloride,
 diphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-trimethylsilylcyclopentad
 ienyl)zirconium dichloride,
 methylphenylmethylene(4,5,6,7-tetrahydro-1-indenyl)(3-trimethylsilylcyclope
 ntadienyl)zirconium dichloride.
 Another possible embodiment of the process according to the invention uses
 a salt-type compound of the formula R.sub.x NH.sub.4-X BR'.sub.4 or of the
 formula R.sub.3 PHBR'.sub.4 as cocatalyst instead of or in addition to an
 aluminoxane.
 Here, x=1, 2 or 3, R=alkyl or aryl, identical or different, and R'=aryl,
 which may also have been fluorinated or partially fluorinated. In this
 case the catalyst is composed of the reaction product of a metallocene
 with one of the compounds mentioned (EP-A-0 277 004).
 Any solvent added to the reaction mixture is a common inert solvent, such
 as an aliphatic or cycloaliphatic hydrocarbon, a gasoline fraction or
 hydrogenated diesel oil fraction, or toluene.
 The metallocenes are preferably used in the form of their racemates. The
 metallocene is preferably used at a concentration, based on the transition
 metal, of from 10.sup.-1 to 10.sup.-8 mol, preferably from 10.sup.-2 to
 10.sup.-7 mol, particularly preferably from 10.sup.-3 to 10.sup.-7 mol, of
 transition metal per dm.sup.3 of reactor volume. The aluminoxane is used
 at a concentration of from 10.sup.-4 to 10.sup.-1 mol, preferably from
 10.sup.-4 to 2.10.sup.-2 mol, per dm.sup.3 of reactor volume, based on the
 aluminum content. In principle, however, higher concentrations are also
 possible.
 The cycloolefin copolymers suitable for the purposes of the invention have
 glass transition temperatures of from 0 to 250.degree. C., preferably from
 20 to 200.degree. C., particularly preferably from 50 to 180.degree. C.
 The COCs suitable for the purposes of the invention have viscosity numbers
 (determined in decalin at 135.degree. C.) of from 25 to 200 ml/g,
 preferably from 40 to 120 ml/g, particularly preferably from 40 to 100
 ml/g.
 The cycloolefin copolymers present in the novel polymer blend have a
 particular structure, which has been described in detail in a dissertation
 by J. Ruchatz, Dusseldorf 1997.
 Accordingly, the cycloolefin copolymers present in the novel polymer blend
 may have sequences of two norbornene units incorporated one after the
 other. Two norbornene units also correspond to the maximum possible
 sequence length of the cycloolefin copolymers present in the novel polymer
 blend.
 Surprisingly, it has been found that the blend of the cycloolefin
 copolymers described with conventional impact modifiers gives materials
 with particularly high impact resistance.
 The cycloolefin copolymers present in the novel polymer blend also have an
 elongation at break E
 of E.gtoreq.-0.0375.cndot.Tg+12, preferably
 of E.gtoreq.-0.0375.cndot.Tg+17, particularly preferably
 of E.gtoreq.-0.0375.cndot.Tg+22.
 The cycloolefin copolymers present in the novel polymer blend also have a
 plateau modulus G'p given by
 log G'p.gtoreq.-0.0035.cndot.Tg+6, preferably
 log G'p.gtoreq.-0.0035.cndot.Tg+6.03, particularly preferably
 log G'p.gtoreq.-0.0035.cndot.Tg+6.06.
 The core-shell particles present in the novel polymer blend have two (core
 and one shell) or more (core and more than one shell) alternating layers
 of different polymers. A feature of all of these particles is that the
 individual layers are composed of polymers with different glass transition
 temperatures Tg. Polymers with a low glass transition temperature are
 termed rubber phase here and polymers with a high glass transition
 temperature are termed hard phase. Particles of this type may be prepared
 by emulsion polymerization, for example. One or more layers may be
 crosslinked chemically during the preparation in order that the shape and
 size of the core-shell particle do not alter during subsequent blending
 with COC.
 Possible uncrosslinked base materials for the crosslinked rubber phases are
 polymer systems whose glass transition temperatures are below 0.degree.
 C., preferably below -20.degree. C. and particularly preferably below
 -40.degree. C. Suitable polymers are in principle all of those which have
 glass transition temperatures of this type and are suitable for
 synthesizing core-shell particles.
 Core-shell particles whose rubber phases have particularly low glass
 transition temperatures Tg are particularly suitable for preparing polymer
 blends which are used for low-temperature applications.
 The glass transition temperatures of the rubber phases can frequently not
 be measured individually, but can be determined by preparing and isolating
 an emulsion polymer of the relevant monomeric composition and determining
 the glass transition temperature. Another method for determining the glass
 transition temperatures of the rubber phases is to measure dynamic
 mechanical properties of the novel polymer blends and those of the matrix
 polymers alone. Maxima in the mechanical loss factor curves can be taken
 as a measure of the glass transition temperatures.
 The percentage by volume of rubber phases present in core-shell particles
 suitable for the purposes of the invention, based on the total volume of
 the particles, is from 10 to 90, preferably from 20 to 70 and particularly
 preferably from 30 to 60.
 The percentage by volume of hard phases present in core-shell particles
 suitable for the purposes of the invention, based on the total volume of
 the particles, is from 90 to 10, preferably from 80 to 30 and particularly
 preferably from 70 to 40.
 The preparation of core-shell particles is well known and described in
 detail in, for example, U.S. Pat. No. 3,833,682, U.S. Pat. No. 3,787,522,
 DE-A-2 116 653, DE-A-22 53 689, DE-A-41 32 497, DE-A-41 31 738, DE-A-40 40
 986, U.S. Pat. No. 3,125,1904 and DE-A-33 00 526.
 The polymers used as rubber phase of the core-shell particles may be homo-
 or copolymers composed of two or more types of monomer. A feature shared
 by these homo- and copolymers is a glass transition temperature below that
 of COC.
 The homo- or copolymers here may derive from the following monomers:
 Conjugated diene monomers, such as butadiene, isoprene and chloroprene,
 monoethylenically unsaturated monomers, such as alkyl and aryl acrylates,
 where the alkyl radicals may be linear, cyclic or branched and the aryl
 radicals may themselves have substitution, alkyl and aryl methacrylates,
 where the alkyl radicals may be linear, cyclic or branched and the aryl
 radicals may themselves have substitution, substituted alkyl and aryl
 methacrylates and acrylates, where the substituents may be linear, cyclic
 or branched alkyl radicals or substituted aryl radicals, acrylonitrile and
 substituted acrylonitriles (e.g. methacrylonitrile,
 alpha-methyleneglutaronitrile, alpha-ethylacrylonitrile,
 alpha-phenylacrylonitrile), alkyl- and arylacrylamides and substituted
 alkyl- and arylacrylamides, vinyl esters and substituted vinyl esters,
 vinyl ethers and substituted vinyl ethers, vinylamides and substituted
 vinylamides, vinyl ketones and substituted vinyl ketones, vinyl halides
 and substituted vinyl halides, olefins with one or more double bonds, as
 used, for example, for preparing olefinic rubbers, in particular ethylene,
 propylene, butylene and 1,4-hexadiene, and also vinylaromatic compounds,
 such as styrene, alpha-methylstyrene, vinyltoluene, halostyrenes and
 tert-butylstyrenes.
 Rubber phases based on organopolysiloxanes of the formula below may also be
 used for building up core-shell particles:
 ##STR4##
 where R are identical or different alkyl or alkenyl radicals having from 1
 to 10 carbon atoms, aryl radicals or substituted hydrocarbon radicals. The
 alkyl and alkenyl radicals here may be linear, branched or cyclic.
 It is also possible to use rubber phases based on fluorinated
 monoethylenically unsaturated compounds, such as tetrafluoroethylene,
 vinylidene fluoride, hexafluoropropene, chlorotrifluoroethylene and
 perfluoro(alkyl vinyl) ethers.
 The rubber phases may also have crosslinking, and for this use may be made
 of polyfunctional unsaturated compounds, such as those described in DE-A-1
 116 653, U.S. Pat. No. 3,787,522 and EP-A-0 436 080. Also described in
 these publications is the use of grafting-on monomers. These compounds are
 used for chemical linking, if desired, of a possible further shell to the
 phase underlying this.
 To obtain polymer blends with good impact resistance, even at low
 temperatures, preference is given to core-shell particles whose rubber
 phases are based on butadiene.
 To obtain polymer blends with good weathering resistance, preference is
 given to core-shell particles whose rubber phases are based on acrylates.
 Core-shell particles whose rubber phases are based on organosiloxanes are
 preferred if the polymer blend is to combine good impact resistance at low
 temperatures, good weathering resistance and good stability during
 preparation and processing from the melt.
 The polymers which may be used for the hard phases of the novel core-shell
 particles are homo- and copolymers. The copolymers here may be composed of
 two or more monomers. A feature shared by appropriate homo- and copolymers
 is a glass transition temperature above 50.degree. C.
 The homo- and copolymers here may derive from the following monomers:
 Monoethylenically unsaturated compounds, such as alkyl and aryl acrylates,
 where the alkyl radicals may be linear, cyclic or branched and the aryl
 radicals may themselves have substitution, alkyl and aryl methacrylates,
 where the alkyl radicals may be linear, cyclic or branched and the aryl
 radicals may themselves have substitution, substituted alkyl and aryl
 methacrylates and acrylates, where the substituents may be linear, cyclic
 or branched alkyl radicals or substituted aryl radicals, acrylonitrile and
 substituted acrylonitriles (e.g. methacrylonitrile,
 alpha-methyleneglutaronitrile, alpha-ethylacrylonitrile,
 alpha-phenylacrylonitrile etc.), alkyl- and arylacrylamides, vinyl esters
 and substituted vinyl esters, vinyl ethers and substituted vinyl ethers,
 vinylamides and substituted vinylamides, vinyl ketones and substituted
 vinyl ketones, vinyl halides and substituted vinyl halides, olefins (e.g.
 ethylene, propylene, butylene), cyclic olefins (e.g. norbomene,
 tetracyclododecene, 2-vinyinorbomene), fluorinated monoethylenically
 unsaturated compounds, such as tetrafluoroethylene, vinylidene fluoride,
 hexafluoropropene, chlorotrifluoroethylene and perfluoro(alkyl vinyl)
 ethers, and also vinylaromatic compounds of the formula:
 ##STR5##
 where R.sub.1, R.sub.2, and R.sub.3 are hydrogen, or linear, branched or
 cyclic alkyl radicals, or substituted or unsubstituted aryl radicals,
 which may be identical or different, and Ar is an aromatic C.sub.6
 -C.sub.18 radical which may additionally bear substituents, such as alkyl
 or halogen radicals.
 The hard phases may have crosslinking, and to this end use may be made of
 polyfunctional unsaturated compounds, such as those described in DE-A-2
 116 653, U.S. Pat. No. 3,787,522 and EP-A-0 436 080. Also described in
 these publications is the use of grafting-on monomers. These compounds are
 used for chemical linking, if desired, of a possible further shell to the
 phase underlying this.
 Polymers which are possible uncrosslinked base materials for the hard
 phases have glass transition temperatures above 50.degree. C., preferably
 above 80.degree. C. and particularly preferably above 100.degree. C.
 The novel polymer blend may also comprise commercially available core-shell
 particles, such as Staphyloid grades from TAKEDA Chem. Industries, for
 example those described in JP 17514 or JP 129266, Kane-Ace grades from
 KANEKA, described, for example, in the Kane ACE-B product brochure,
 Metablen C, Metablen W and Metablen E grades from METABLEN Company BV,
 described in the Metablen product brochure, Blendex grades from GE
 PLASTICS or Paraloid grades from ROHM and HAAS, described, for example, in
 Gachter/Muller Kunststoff-Additive [Plastics Additives], Carl Hanser,
 Munich (1983) pages XXIX et seq. or in the ALOID BTA 733 brochure,
 Impact Modifiers for Clear Packaging (1987) from Rohm and Haas or in the
 ALOID BTA-III N2 BTA-702 BTA 715 brochure (1989) from Rohm and Haas.
 If core-shell particles are used as impact modifiers, the novel polymer
 blends comprise from 2 to 50% by weight, preferably from 10 to 40% by
 weight and particularly preferably from 10 to 25% by weight, of core-shell
 particles, based on the entire blend.
 As an alternative to core-shell particles, the impact modifiers used may be
 copolymers which are composed to some extent of rubbers with low glass
 transition temperatures.
 The block polymers present in the novel blend contain one or more block
 types with a glass transition temperature &gt;40.degree. C. and one or more
 block types with a glass transition temperature &lt;-20.degree. C. Preference
 is given to structural COC polymers which have alternating blocks of
 different cycloolefin content (EP-A-0 560 090, expressly incorporated
 herein by way of reference) and to block polymers obtained by anionic
 polymerization. Di-and triblock copolymers are preferred.
 The block types with a glass transition temperature &gt;40.degree. C. are
 preferably composed of polymers which are prepared by anionic
 polymerization, for example polystyrene, polyesters or polyurethanes. The
 block types with a glass transition temperature &lt;-20.degree. C. are
 preferably composed of homo- or copolymers which contain polybutadiene,
 polysiloxane, polyisoprene, hydrogenated polybutadiene or hydrogenated
 polyisoprene.
 If the copolymers used are composed to some extent of rubbers with low
 glass transition temperatures, the novel polymer blends comprise, based on
 the entire blend, from 2 to 50% by weight, preferably from 10 to 40% by
 weight, particularly preferably from 10 to 25% by weight, of copolymers as
 impact modifiers.
 Other impact modifiers which may be used for the purposes of the invention
 include combinations of one or more of the core-shell particles described
 above and one or more of the copolymers described above which are composed
 to some extent of rubbers with low glass transition temperatures.
 If this combination of impact modifiers is used, the novel polymer blends
 comprise from 2 to 50% by weight, preferably from 10 to 40% by weight,
 particularly preferably from 10 to 25% by weight, of the combination,
 based on the entire blend, and the constituents of the combination may be
 present in any desired mixing ratio.
 To achieve very high transparency of the polymer blends, suitable
 core-shell particles and copolymers which are composed to some extent of
 rubbers with low glass transition temperatures are those with average
 refractive indices (volume-average) of from 1.52 to 1.55, preferably from
 1.53 to 1.54. The selection of ideal refractive indices and radius
 relationships for the particles in any particular case is determined as in
 Makromol. Chem. 183 (1990), 221 for particles made from a core and one
 shell or as in M. Kerker, The Scattering of Light, Academic Press (1969),
 Chapter 5.4 for particles with more than one shell. Core-shell modifiers
 with a multilayer structure, composed of a core and of more than one
 shell, are particularly suitable for obtaining transparent impact-modified
 polymer blends.
 The novel polymer blends are prepared at temperatures above the glass
 transition temperature of the cycloolefin polymer at from 60 to
 350.degree. C., preferably from 100 to 150.degree. C. and particularly
 preferably from 110 to 130.degree. C.
 The novel polymer blends may be prepared by conventional processes (D. D.
 Walsh, Comprehensive Polymer Science, Pergamon Press (1989), Chapter 5.2;
 J. L. White and K. Min, Comprehensive Polymer Science, Pergamon Press,
 (1989), page 285 et seq.) In particular, the components in the form of
 powders or pellets may be processed by extruding them together from the
 melt to give pellets or chips which can then be converted into molded
 structures, e.g. by compression molding, extrusion or injection molding.
 The novel polymer blend is particularly suitable for producing moldings by
 injection molding, injection blow molding, extrusion blow molding or
 extrusion. The novel polymer blend may also be used to produce films or
 fibers.
 The novel polymer blends may in particular be prepared via masterbatches.
 For this, core-shell particles and/or copolymers which are composed to
 some extent of rubbers with low glass transition temperatures are mixed in
 amounts of from 20 to 80% by weight, based on the weight of the entire
 polymer blend, with one or more cycloolefin copolymers (preferably by
 extruding them together) and then brought to the desired final
 concentration by further mixing with one or more cycloolefin copolymers
 (preferably by extruding them together). This method gives good dispersion
 of the impact modifiers and is preferred for producing polymer blends with
 contents of from 3 to 25% by weight of impact modifiers, based on the
 weight of the entire polymer blend.
 The novel polymer blend has an elongation at break of from 4 to 200%,
 preferably from 5 to 100%, particularly preferably from 10 to 30%, and
 notched impact strength of from 2.5 to 100 KJ/m.sup.2, preferably from 4
 to 50 KJ/m.sup.2, particularly preferably from 10 to 30 KJ/m.sup.2. The
 novel polymer blend comprising at least one amorphous cycloolefin
 copolymer has high resistance to temperature variation and chemicals
 resistance.
 The polymer blends may contain conventional amounts of additives, such as
 plasticizers, UV stabilizers, optical brighteners, antioxidants, antistats
 and heat stabilizers, or reinforcing additives, such as glass fibers,
 carbon fibers, or high-modulus fibers, such as polyaramids or
 liquid-crystalline polyesters or the like. They may also comprise fillers,
 such as inorganic materials, talc, titanium dioxide or the like.
 The novel polymer blend is suitable for a wide variety of applications,
 such as containers, bottles and drinking cups, and applications in medical
 technology, such as blister packs and injection moldings for anesthesia,
 artificial respiration, pediatrics and equipment for medical care,
 household products, such as cutlery, microwave cookware, freezer
 containers, bowls, troughs, trays and tubs, in particular bathtubs,
 clothes pegs, toilet seats, water faucets, furniture, luggage, in
 particular shell-type luggage, flower vases, lids and closures for
 bottles, toys, such as building blocks and pedal cars, lamp housings,
 percussion drills, belt grinders, vibrating grinders and sanders, buzz
 saws, and low-temperature applications, such as refrigerator inserts or
 freezer parts, cable sheathings, pipes, sports equipment, such as safety
 helmets, ship's hulls and surfboards, internal fittings for automobiles,
 such as trims or dashboards, external fittings for automobiles, such as
 bumpers, door paneling and wheel caps, and semifinished products, such as
 gaskets, pipe connectors and cable ties.
 The novel polymer blend has high flexural strength and high environmental
 stress cracking resistance, and also good melt stability. It has good
 weldline strength and good flowabiiity, particularly advantageous for
 injection molding applications. Its mechanical properties, such as heat
 distortion temperature, elongation at break and notched impact strength,
 can be varied within a wide range to give access to a wide variety of
 applications.
 The glass transition temperatures Tg given in the examples which follow
 were determined using DSC (Differential Scanning Calorimetry) with a
 heating rate of 20.degree. C./min. The viscosity numbers VN given were
 determined to DIN 53728 in dichlorobenzene at 135.degree. C. The
 weight-average molar mass and polydispersity were determined using GPC.
 Elongations at break and yield stresses were determined from tensile tests
 in accordance with ISO 527 Parts 1 and 2, the speed for the test being set
 at 50 mm/min.
 The melt rheology properties for plateau modulus determination were
 determined in a dynamic vibration test using Rheometrics
 shear-rate-controlled equipment with plate-plate geometry at frequencies
 of 10.sup.-1 to 5C10.sup.2 5.sup.-1.
 The yield of polymer per unit of time and per mmol of metallocene is
 utilized to measure the activity of the catalyst:
 ##EQU1##

The following examples describe the invention in more detail:
 EXAMPLES
 Blend preparation
 The mixtures were prepared on a Haake TW 100 laboratory extruder, a conical
 twin-screw extruder, with intensive-mixing screws and a 1.7 mm die. For
 Examples 3 to 7 and Comparative Examples 3 to 7 processing ;temperatures
 were 140/200/210/205.degree. C. and rotation rate was 75 rpm. For Examples
 8 to 14 and Comparative Examples 8 to 14 processing temperatures were
 160/230/240/235.degree. C. and rotation rate was 100 rpm. Test specimens
 were produced on a Kraus-Maffei KM 90-210 injection molding machine. For
 Examples 3 to 7 and Comparative Examples 3 to 7 the temperature profile
 was 250/250/245/240.degree. C., injection pressure was 37 bar, hold
 pressure time was 10 s, mold temperature was 60.degree. C., hold pressure
 was 36 bar and cooling time was 90 s. For examples 8 to 14 and Comparative
 Examples 8 to 14 temperature profile was 270/270/265/265.degree. C.,
 injection pressure was 35 bar, hold pressure time was 10 s, mold
 temperature was 110.degree. C., hold pressure was 36 bar and cooling time
 was 90 s.
 Preparation of the cycloolefin copolymers
 Examples 1 and 2
 A 40% strength by weight solution of norbornene in toluene was charged to a
 70 dm.sup.3 autoclave which had previously been flushed with ethene. The
 solution was saturated with ethene by repeated exposure to ethene under
 pressure. A toluene solution of methylaluminoxane (10% strength by weight
 of methylaluminoxane of molar mass 1300 g/mol determined cryoscopically)
 was metered countercurrently into the reactor prepared in this way,
 followed by stirring at 70.degree. C. for 30 minutes. After 30
 minutes'preactivation, a solution of 9 mg in total of the metallocene
 isopropylene (1-indenyl)(3-isopropylcyclopentadienyl)zirconium dichloride
 in toluene was added.
 Polymerization was carried out for one hour with stirring and with further
 feed of ethylene to hold the ethylene pressure constant at 20 bar.
 After the end of the reaction time, the polymerization mixture was
 discharged into a vessel and immediately introduced into 300 dm.sup.3 of
 acetone and stirred for 30 minutes, and the precipitated product was then
 filtered. The filter cake was washed three times, in each case alternately
 with 10% strength hydrochloric acid and acetone, and the residue was
 slurried in acetone and filtered again. The purified product obtained was
 dried in vacuo (0.2 bar) at 40.degree. C. for 24 hours.
 This gave 4.9 kg of a colorless polymer with a VN of 67 ml/g, a glass
 transition temperature of 82.degree. C. and a plateau modulus G'p of
 600,000. This product is termed COC 1 below. COC 2 was prepared using the
 same catalyst, but in contrast to the procedure given above 39 mg of
 catalyst were used, the total pressure was 7 bar, the ethylene pressure
 was 1.1 bar and the total ethylene consumption was 2000 g. This gave 6.5
 kg of a polymer with a glass transition temperature of 137.degree. C., a
 viscosity number of 53 ml/g and a plateau modulus G'p of 480,000.
 Comparative Examples 1 and 2
 Comparative Example 1 was prepared from a 46% strength by weight norbomene
 solution in toluene with 30 mg of the metallocene
 isopropylenebis(1-indenyl)zirconium dichloride. The ethylene pressure was
 20 bar and the hydrogen pressure was 2000 ppm. The resultant polymer has a
 glass transition temperature of 86.degree. C., a viscosity number of 62
 ml/g and a plateau modulus G'p of 420,000. This product is termed COC 3.
 Comparative Example 2 was prepared from a 60% strength by weight norbomene
 solution in decalin with 70 mg of isopropylene(cyclopentadienyl)
 (1-indenyl)zirconium dichloride. The ethylene pressure was 12 bar. The
 resultant polymer has a glass transition temperature of 140.degree. C., a
 viscosity number of 63 ml/g and a plateau modulus G'p of 300,000. This
 product is termed COC 4.
 Description of the modifiers used
 Kane Ace B582 is a core-shell modifier with a core-shell ratio of 70:30,
 purchased from Kaneka. The core is composed of an uncrosslinked
 butadiene-styrene copolymer and the shell of methyl
 methacrylate-styrenebutyl acrylate.
 Paraloid EXL 2600 is a core-shell modifier based on MBS
 (methyacrylate-butadiene-styrene), obtainable from Rohm & Haas.
 Kraton D 1184 CS is a commercial product from German Shell. It is a
 branched styrene-butadiene block copolymer with a proportion of 30% of
 styrene, a Shore A hardness of 75 and 820% elongation at break.
 Septon 1050 is a product of Kuraray Europe GmbH. It is a
 styrene-ethylene-propylene block copolymer with a proportion of 50%
 styrene, a Shore A hardness of 97 and greater than 100% elongation at
 break.
 Septon 2104 is another product from Kuraray Europe GmbH. It is a
 styrene-ethylene-propylene-styrene block copolymer with a styrene content
 of 65%, a Shore A hardness of 98 and greater than 100% elongation at
 break.