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Calenderable propylene polymer compositions |
| T973011 |
Calenderable propylene polymer compositions
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| Inventor: |
Waghorn |
| Date Issued: |
August 1, 1978 |
| Application: |
05/812,439 |
| Filed: |
July 1, 1977 |
| Inventors: |
Waghorn; Peter Ernest (Welwyn Garden City, Hertfordshire, GB2)
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| U.S. Class: |
524/101; 524/291; 524/342; 524/349; 524/350; 524/400 |
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| Abstract: |
crystalline polypropylene compositions of low melt flow index which can be calendered into foils having a melt flow index of below 5 are obtained by using a soap and a particulate inorganic material together with highly effective stabilizer systems. Low melt flow index polypropylene polymers and copolymers are rendered adequately resistant to degradation while in the molten state associated with a calendering process. A composition calenderable into foils and which comprises:A. a crystalline homopolymer of propylene and/or a crystalline copolymer of propylene with up to 25%, preferably from over 5 up to 17%, by weight of ethylene,B. from 0.1 to 1.5%, preferably 0.15 to 0.3%, by weight of a "highly effective stabilizer system" as defined below,C. from 0.1 to 2.0%, preferably 0.15 to 0.8%, by weight of a soap as described, andD. 10 to 60%, preferably 15 to 45% by weight of a solid particulate inorganic material is described.The percentages quoted are based on the weight of the polymer and/or copolymer present in the composition.Preferred highly efficient stabilizers are pentaerythritol tetra-.beta.-3,5-ditertiary butyl-4-hydroxyphenyl propionate and tris(3,5-ditertiary butyl-4-hydroxybenzyl) isocyanurate but stabilizers such as 2,6-ditertiary butyl-4-methyl phenol or 1,1,3-tris(2'-methyl-5'-tertiary butyl-4-hydroxy phenyl) butane are also effective. |
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