Polymer mixture containing an amorphous polyolefin which...

Details Polymer mixture containing an amorphous polyolefin which... Polymer mixture containing an amorphous polyolefin which...

2002-10-31

2004-07-27

Nutter, Nathan M. (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...

C525S241000

Reexamination Certificate

active

06767966

ABSTRACT:

The present invention relates to a novel transparent polymer mixture with modified relaxation behavior and modified shrinkage behavior, comprising cycloolefin polymers.
The relaxation behavior of polymers is a description of change in modulus of elasticity as a function of temperature and frequency. The relaxation behavior of a cycloolefin polymer or of a known cycloolefin mixture exhibits a steep fall-off in modulus of elasticity within a narrow temperature range, what is known as the glass transition range or softening range.
Shrinkage behavior is a description of the change in length of mono- or biaxially oriented test specimens as a function of temperature or time.
Delfolie et al., Macromolecules 32, 1999, 7781-7789, studies the miscibility of ethylene-norbornene copolymers. DSC is used to indicate the limits of miscibility: the occurrence of a single glass transition temperature is regarded as a measure of miscibility, while immiscibility is apparent in the occurrence of two separate glass transitions.
Utracki, Polymer Alloys and Blends—Thermodynamics and Rheology, 2
nd
edition, Munich, Hanser 1989, 3 et seq., gives a general description of modulus of elasticity as a function of temperature for 50/50 polymer mixtures in the vicinity of the glass transition temperature. For homogeneously miscible polymers, a steep fall-off in the modulus is found at a central glass transition temperature. For immiscible polymers, two steps in the modulus of elasticity, and therefore two glass transition temperatures, are observed, corresponding to those of the starting materials. For partially miscible polymers, two steps in the modulus of elasticity, and therefore two glass transition temperatures, are observed, and are slightly different from those of the starting materials. For immiscible polymers with fine dispersion below 15 nm, referred to as compatible polymers, a broad glass transition temperature range is found, with a slight fall-off in the modulus of elasticity.
Hsiue and Ye, J. Appl. Pol. Sci. 37, 1989, 2803-2836, describe the shrinkage behavior of oriented polyester films above the glass transition temperature. It is shown that shrinkage behavior of amorphous polymers in this range is determined by the degree of intertwining of the polymer chains. An increase in the molecular weight and a lowering of the orientation temperature lead to greater shrinkage.
U.S. Pat. No. 5,824,398 and U.S. Pat. No. 5,589,126 indicate that addition of a plasticizer to polyester shifts the temperature of shrinkage onset in oriented films to lower temperatures.
A substantial disadvantage of the steep fall-off in the modulus of elasticity with temperature is that there is only a narrow possible temperature range for the elongation of test specimens. This is relevant, for example, in the case of mono- or bi-axial orientation of films. The steep fall-off in modulus of elasticity as a function of temperature also brings about rapid change in the shrinkage of oriented films with temperature. As a result, the films produced give unsatisfactory results when shrunk onto irregularly shaped test specimens. The marked change in length of oriented test specimens with temperature acts together with a high degree of intertwining of the polymer chains to exert a strong shrinkage force on the test specimen, and if wall thickness is low this can lead to undesired volume change. There has therefore been a longstanding desire to find a way of influencing the temperature-dependency of modulus of elasticity in the glass transition region, and of shrinkage, while at the same time retaining transparency.
The object of the present invention is to provide a novel transparent polymer mixture, comprising cycloolefin polymers, with modified relaxation behavior and modified shrinkage behavior.
The object of the present invention is achieved by way of a polymer mixture comprising at least one amorphous polyolefin. Surprisingly, addition of an amorphous polyolefin brings about an unexpected change in the modulus of elasticity and in the shrinkage behavior in relation to temperature.
The mixture of the invention preferably comprises at least one cycloolefin polymer. Addition of at least one amorphous polyolefin to the cycloolefin polymer brings about good results in terms of change in modulus of elasticity and in shrinkage behavior in relation to temperature.
The mixture of the invention preferably comprises at least one amorphous cycloolefin polymer. Addition of at least one amorphous cycloolefin polymer to a cycloolefin polymer brings about particularly good results in terms of change in modulus of elasticity and in shrinkage behavior in relation to temperature.
The mixture of the invention comprises at least one cycloolefin polymer, containing from 0.1 to 100% by weight, preferably from 0.1 to 99.9% by weight, based on the total weight of the cycloolefin copolymer, of polymerized units which derive from at least one polycyclic olefin of the formulae I, II, II′, III, IV, V or VI
where 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 radical, such as a linear or branched C
1
-C
8
-alkyl radical, C
6
-C
18
-aryl radical, C
7
-C
20
-alkylene-aryl radical, or a cyclic or acyclic C
2
-C
20
-alkenyl radical, or form a saturated, unsaturated, or aromatic ring, where the same radicals R
1
to R
8
in the various formulae I to VI may have a different meaning, and where n can assume values from 0 to 5, and containing from 0 to 99.9% by weight, preferably from 0.1 to 99.9% by weight, based on the total weight of the cycloolefin copolymer, of polymerized units which derive from one or more acyclic olefins of the formula VII
where R
9
, R
10
, R
11
, and R
12
are identical or different and are a hydrogen atom, or a linear or branched, saturated or unsaturated C
1
-C
20
-hydrocarbon, radical, such as a C
1
-C
8
-alkyl radical or a C
6
-C
18
-aryl radical.
The cycloolefin copolymers used according to the invention may moreover contain from 0 to 45% by weight, based on the total weight of the cycloolefin copolymer, of polymerized units which derive from one or more monocyclic olefins of the formula VIII
where m is a number from 2 to 10.
The cyclic olefins likewise include derivatives of these cyclic olefins having polar groups, such as halogen groups, hydroxy groups, ester groups, alkoxy groups, carboxy groups, cyano groups, amido groups, imino groups, or silyl groups.
For the purposes of the invention, preference is given to cycloolefin copolymers which contain polymerized units which derive from polycyclic olefins of the formulae I or III, and contain polymerized units which derive from acyclic olefins of the formula VII.
Particular preference is given to cycloolefin copolymers which contain polymerized units which derive from olefins with underlying norbornene structure, very particularly preferably from norbornene and tetracyclo-dodecene, and, where appropriate, vinylnorbornene or norbornadiene.
Particular preference is also given to cycloolefin copolymers which contain polymerized units which derive from acyclic olefins having terminal double bonds, such as &agr;-olefins having from 2 to 20 carbon atoms, very particularly preferably ethylene or propylene. Very great preference is given to norbornene-ethylene copolymers and tetracyclododecene-ethylene copolymers.
Among the terpolymers, particular preference is given to norbornene-vinyl-norbornene-ethylene terpolymers, norbornene-norbornadiene-ethylene terpolymers, tetracyclododecene-vinyinorbornene-ethylene terpolymers, tetracyclododecene-vinyltetracyclododecene-ethylene terpolymers, and norbornene-dicyclopentadiene-ethylene. The proportion of the polymerized units which derive from a polyene, preferably vinylnorbornene or norbornadiene, is from 0.1 to 50 mol %, preferably from 0.1 to 20 mol %, and the proportion of the acyclic monoolefin of the formula VII is from 0 to 99.9 mol %, preferably from 5 to 80 mol %, based on the total makeup of the cycloolefin polymer. In the terpolymers described, the

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