Films from polymer blends
AssigneeExxonMobil Chemical Patents Inc.
InventorsAspy K. Mehta, Sudhin Datta, Wen Li, Srivatsan Srinivas Iyer
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Abstract
This invention relates to a film comprising a heterogeneous blend of: 1) from 60 to 99 wt % of one or more semi-crystalline polymers; and 2) from 1 to 40 wt % of one or more semi-amorphous polymers; where the blend has: an MFR of 0.5 to 100 dg/min, a haze of 20% or less, and a permanent set of greater than 65%; and where the film is 2.5 to 635 microns thick and has: a haze of 10% or less, a 1° Secant tensile modulus of 100,000 to 30,000 psi, an Elmendorf tear in the machine direction and transverse direction of 45 g/mil or more, a total energy impact of 3 J or more; and a 45 degree gloss of 82 or more.
Claims77
A film comprising a heterogeneous blend of:
- 1) from 60 to 99 weight percent of one or more semi-crystalline polymers (based upon the weight of the semi-crystalline and semi-amorphous polymers), each semi-crystalline polymer comprising propylene and from 0 to 5 weight % alpha-olefin comonomer (based upon the weight of the polymer), said semi-crystalline polymers each having a melting point between 100 and 170° C. and a melt flow rate of 200 dg/min or less;
- and
- 2) from 1 to 40 weight % of one or more semi-amorphous polymers (based upon the weight of the semi-crystalline and semi-amorphous polymers), each semi-amorphous polymer comprising propylene and from 10 to 25 weight % of one or more C2 and or C4 to C10 alpha-olefin comonomers, said semi-amorphous polymers each having:
- a) heat of fusion of 4 to 70 J/g;
- b) a melt flow rate of 0.1 to 200 dg/min;
- c) an intermolecular composition distribution as determined by thermal fractionation in hexane such that 85% by weight or more of the polymer is isolated as one or two adjacent, soluble fractions with the balance of the polymer in immediately preceding or succeeding fractions;
- and wherein each of these fractions has a wt % comonomer content with a difference of no greater than 20 wt % relative to the average wt % comonomer content of the copolymer;
- d) an Mw/Mn of 1.5 to 4,
- e) a propylene triad tacticity, as measured by 13C NMR, of 75% or greater;
- where the blend has:
- i) a melt flow rate of 0.5 to 100 dg/min;
- and
- ii) 0 to 5 weight % filler, based upon the weight of the polymers and the filler;
- and
- iii) a haze of 20% or less measured on a 1 mm thick injection molded chip;
- and
- iv) a permanent set of greater than 65%;
- and
- where the film is 0.1 to 25 mil (2.5 to 635 micron) thick and has:
- a haze of 10% or less,
- a 1° Secant tensile modulus of 100,000 to 30,000 psi,
- an Elmendorf tear in the machine direction of 45 g/mil or more,
- an Elmendorf tear in the transverse direction of 45 g/mil or more,
- a total energy impact of 3 J or more;
- and
- a 45 degree gloss of 82 or more.
The film of any of the above claims wherein the semi-crystalline polymer has a melting point of 120 to 170° C.
Dependencies are inferred from the claim text.