Claims
- 1. A stabilized grafted polyethylene exhibiting a standard density (measured according to ISO standard 1183-1987) of 930 to 960 kg/m.sup.3, a melt index (measured according to ISO standard 1133-1991 under a 5 kg load and at 190.degree. C.) of 0.05 to 20 g/10 min, a graftable functional monomer content of 0.01 to 10 parts by weight per 100 parts by weight of polyethylene and a total antioxidant additive content of 0.01 to 10 parts by weight per 100 parts by weight of polyethylene.
- 2. A continuous process for grafting a polyolefin within a melt including the polyolefin, a graftable functional monomer and a radical-generator, in an extruder including at the entry a feed zone into which the polyolefin, the graftable functional monomer and the radical-generator are introduced at least partially, and at its exit a discharge zone and including, between the discharge zone and the spot situated midway along the extruder, one or several blending members followed by one or several lefthanded conveying members.
- 3. The process according to claim 2, wherein the extruder additionally comprises a melting zone situated immediately after the feed zone, and a compression zone preceding the discharge zone.
- 4. The process according to claim 3, wherein the melting zone consists of blending members, and the compression zone of righthanded conveying members.
- 5. The process according to claim 3, wherein the extruder additionally comprises an additional reaction zone arranged immediately after the melting zone, and a degassing zone situated after the reaction zone and before the compression zone.
- 6. The process according to claim 5, wherein the additional reaction zone is made up of righthanded conveying members and of blending members, and the degassing zone of righthanded conveying members.
- 7. The process according to claim 6, wherein, the total length of the blending members in the additional reaction zone, does not exceed 20% of the total length of the righthanded conveying members.
- 8. The process according to claim 2, wherein the extruder includes, at its exit, a compression zone preceding the discharge zone, and wherein at least one antioxidant additive is introduced into the melt not later than before the latter enters the compression zone.
- 9. The process according to claim 8, wherein the sequence of one or several blending members which are followed by one or several lefthanded conveying members is arranged between the place where the antioxidant additive is introduced and the discharge zone.
- 10. A process for the treatment of granules of a grafted polyolefin, according to which the granules of grafted polyolefin are brought into contact with a gaseous medium saturated with water vapor at a temperature of at least 80.degree. C. for at least one (1) minute.
- 11. The process according to claim 10, wherein the partial pressure of water vapor in the gaseous medium is approximately 0.1 Mpa.
- 12. The process according to claim 10, wherein the granules are brought into contact with a gaseous medium containing water vapour at a temperature of at least 90.degree. C. and not more than 200.degree. C.
- 13. The process according to claim 10, wherein the graftable functional monomer is chosen from the group consisting of unsaturated anhydrides of a mono- or dicarboxylic acid.
- 14. The process according to claim 10, wherein the grafted polyolefin is prepared in an extruder within a melt including the polyolefin, a graftable functional monomer and a radical-generator.
- 15. The process according to claim 14, wherein the grafted polyolefin is prepared in an extruder including, at its exit, a compression zone preceding a discharge zone, and wherein at least one antioxidant additive is introduced into the melt not later than before the latter enters the compression zone of the extruder.
- 16. The process according to claim 14, wherein the extruder includes, at the entry, a feed zone into which the polyolefin, the graftable functional monomer and the radical-generator are introduced at least partially, a discharge zone at its exit and, between the discharge zone and the spot situated midway along the extruder, one or several blending members followed by one or several lefthanded conveying members.
- 17. Granules of grafted polyolefin exhibiting a melt index of stability of at least 0.90, defined as the ratio of, on the one hand, the melt index measured after storage of the granules for 48 hours at ambient temperature, at atmospheric pressure and in a gaseous medium saturated with water vapour, to, on the other hand, the melt index measured immediately after the manufacture of the granules (the manufacture including any subsequent treatment following the granulation) and before storage.
- 18. The Granules according to claim 17, being obtained from polyethylene and exhibiting a standard density (measured according to ISO standard 1183-1987) of 930 to 960 kg/m.sup.3, a melt index (measured according to ISO standard 1133-1991 under a 5 kg load and at 190.degree. C.) of 0.05 to 20 g/10 min and a grafted functional monomer content of 0.01 to 10 parts by weight per 100 parts by weight of polyethylene.
- 19. The granules according to claim 17 obtained by a process according to which the granules of grafted polyolefin are brought into contact with a gaseous medium containing water vapour.
- 20. A stabilized grafted polyolefin exhibiting a grafted functional monomer content from 0.01 to 10 parts by weight and a total antioxidant content from 0.01 to 10 parts by weight, each per 100 parts by weight of polyolefin, an antioxidant being introduced into a melt of polyolefin, functional monomer, and radical-generator not later than before said melt enters a compression zone in an extruder including an exit and a discharge zone preceding said compression zone at said extruder's exit.
- 21. The process according to claim 10, wherein the polyolefin polyethylene.
- 22. The process according to claim 13, wherein the graftable functional monomer is maleic anhydride.
Priority Claims (1)
Number |
Date |
Country |
Kind |
09301469 |
Dec 1993 |
BEX |
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of application Ser. No. 08/361,809 filed Dec. 22, 1994, the entire disclosure of which is incorporated herein by reference.
US Referenced Citations (10)
Foreign Referenced Citations (3)
Number |
Date |
Country |
2026900 |
Apr 1991 |
CAX |
62-011703 |
Jun 1987 |
JPX |
5002919 |
Jan 1993 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Chemical Abstracts, Abstract No. 105:154162c; vol. 105, No. 9, p. 45, "Propylene Polymer Compositions", Hamada Yoshinori et al. (Nov. 1, 1986). |
Continuations (1)
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Number |
Date |
Country |
Parent |
361809 |
Dec 1994 |
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