Medium density polyethylene compositions for film applications
First Claim
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1. A coextruded film consisting of:
- (i) a first layer of a composition comprising a low density polyethylene (LDPE) prepared with a non-metallocene catalyst and/or a linear low density polyethylene (LLDPE) prepared with either a non-metallocene or a metallocene catalyst;
(ii) a second layer of a homogeneous blend of a low density polyethylene (LDPE) with a metallocene catalysed medium density polyethylene (mMDPE), this blend essentially consisting of from 0.5 to 99.5% by weight of mMDPE and from 99.5 to 0.5% by weight of LDPE, based on the total weight of the blend, and having a density of from 0.925 to 0.955 g/cm3, and the metallocene catalyst system essentially consisting of a bridged metallocene compound, alone or in combination with another metallocene catalyst which contributes less than 80% by weight of said metallocene;
(iii) a third layer of a composition comprising a low density polyethylene (LDPE)prepared with a non-metallocene catalyst and/or a linear low density polyethylene (LLDPE) prepared either with a non-metallocene or a metallocene catalyst, said third layer being the same as or different from the first layer;
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Abstract
Use of a homogeneous blend of a metallocene-catalysed medium density polyethylene (mMDPE) with low density polyethylene (LDPE), to produce blown films, this composition essentially consisting of from 0.5 to 99.5 % by weight of mMDPE and from 99.5 to 0.5 % by weight of LDPE, based on the total weight of the blend. The blend is optionally coextruded between layers of LDPE.
The compositions of this invention have good processability and are used to make blown films which have the good optical properties of LDPE and the good mechancial and processing properties of MDPE.
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12 Claims
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1. A coextruded film consisting of:
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(i) a first layer of a composition comprising a low density polyethylene (LDPE) prepared with a non-metallocene catalyst and/or a linear low density polyethylene (LLDPE) prepared with either a non-metallocene or a metallocene catalyst;
(ii) a second layer of a homogeneous blend of a low density polyethylene (LDPE) with a metallocene catalysed medium density polyethylene (mMDPE), this blend essentially consisting of from 0.5 to 99.5% by weight of mMDPE and from 99.5 to 0.5% by weight of LDPE, based on the total weight of the blend, and having a density of from 0.925 to 0.955 g/cm3, and the metallocene catalyst system essentially consisting of a bridged metallocene compound, alone or in combination with another metallocene catalyst which contributes less than 80% by weight of said metallocene;
(iii) a third layer of a composition comprising a low density polyethylene (LDPE)prepared with a non-metallocene catalyst and/or a linear low density polyethylene (LLDPE) prepared either with a non-metallocene or a metallocene catalyst, said third layer being the same as or different from the first layer;
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification