Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1997-11-17
1999-11-16
Hampton-Hightower, P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
525179, 525184, 525187, 4284745, C08L 7702, C08L 2712
Patent
active
059860057
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a composition comprising a fluoro elastomer and a thermoplastic polyamide, which is intended to improve the use of plastics. The invention also relates to a composition based on hydrocarbon polymers comprising a fluoro elastomer and a thermoplastic polyamide. The present invention moreover relates to a homogeneous thermoplastic film having improved optical and mechanical properties and comprising modifiers such as a fluoro elastomer and a thermoplastic polyamide.
BACKGROUND OF THE INVENTION
It is generally accepted that during the extrusion of plastic, irregularities in the flow appear at the die outlet when a critical shear rate is exceeded. Below this rate, the extrudates are smooth, whereas, above this critical rate, surface defects are observed. These defects, which are referred to as "melt fracture", are in several forms. At a shear rate slightly above the critical rate, the films obtained by extrusion-blow moulding lose their transparency and their sheen. For markedly higher rates, which correspond to a higher production efficiency, homogeneity defects with smooth zones in a rough surface appear. These defects significantly decrease the optical and mechanical properties of the film. The same phenomena may be observed on extruded rods. When the surface of the rods loses its sheen and becomes dull and rough, it is often compared to an "orange skin".
Among the various solutions proposed to overcome this drawback, the use of modifiers is of greater value industrially. Thus, in U.S. Pat. No. 3,334,157, the incorporation of polytetrafluoroethylene improves the optical properties of the polyethylene film. According to U.S. Pat. Nos. 4,855,360 and 5,015,693, a fluoro elastomer in combination with a polyoxyalkylene is used to improve the conversion of hydrocarbon polymers. Organophosphates or organophosphites in combination with a fluoro elastomer have been described in U.S. Pat. Nos. 4,983,677 and 4,863,983 in order also to improve the conversion of hydrocarbon polymers.
However, additives such as anti-blocking agents, fillers, pigments, dyes and stearates, which are essential for the conversion of plastics, interact with these fluoro elastomers and significantly reduce their efficacy. To attempt to overcome this drawback, one process consisting in firstly treating the extruder die with modifiers and then in converting the plastics has been described in patent WO 91/05007. The modifier used contains a functionalized fluoro copolymer comprising tetrafluoroethylene units and a functional group containing a fluoro monomer. This process has the drawback of taking place in two steps.
DESCRIPTION OF THE INVENTION
A composition has now been found which improves the conversion of plastics, during their use by extrusion, without, however, having the drawbacks mentioned above. This composition comprising a fluoro elastomer and a thermoplastic polyamide forms the subject of the present invention.
The present invention makes it possible not only to shift the "melt fracture" towards high shear rates but also to obtain homogeneous films with a reduced period of establishing the extruder conditions.
The present invention thus provides a composition of modifiers for improving the conversion of plastics, characterized in that it comprises
The thermoplastic polyamides are polymers containing polyamide blocks and polyether blocks.
The polymers containing polyamide blocks and polyether blocks result from the copolycondensation of polyamide sequences containing reactive ends with polyether sequences containing reactive ends, such as, inter alia: sequences containing dicarboxylic chain ends. polyoxyalkylene sequences containing diamine chain ends obtained by cyanoethylation and hydrogenation of alpha-omega-dihydroxy aliphatic polyoxyalkylene sequences, known as polyether diols. diols, the products obtained being, in this specific case, polyetheresteramides.
The polyamide sequences containing dicarboxylic chain ends originate, for example, from the condensation of alph
REFERENCES:
patent: 3334157 (1967-08-01), Larsen
patent: 4115475 (1978-09-01), Foy et al.
patent: 4195015 (1980-03-01), Deleens et al.
patent: 4230836 (1980-10-01), Canterino
patent: 4331786 (1982-05-01), Foy et al.
patent: 4332920 (1982-06-01), Foy et al.
patent: 4839441 (1989-06-01), Cuzin et al.
patent: 4855360 (1989-08-01), Duchesne
patent: 4863983 (1989-09-01), Johnson et al.
patent: 4864014 (1989-09-01), Cuzin et al.
patent: 4983677 (1991-01-01), Johnson et al.
patent: 5015693 (1991-05-01), Duchesne
patent: 5304422 (1994-04-01), Tanabe et al.
Jacquemet Regis
Labaig Jean-Jacques
Merziger Joachim
Elf Atochem S.A.
Hampton-Hightower P.
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