|Title of Invention||
A COMPOSITION AND A METHOD OF STABILIZING POLYMERS
|Abstract||The present invention relates to a composition and a method of stablizing polymers, comprising: bis(2,4-dicumylphenyl) pentaerythritol disphosphite; and at least one metal salt of a lactic acid.|
|Full Text||The present invention relates to a composition and a method of stabilizing polymers comprising bis(2,4-dicumylphenyl) pentaerythritol diphosphite and at least one metal salt of a lactic acid.
The use of phosphites as polymer stabilizers is well known in the art. In particular, the use of penta erythritol diphosphites having superior hydrolytic stability over other phosphites has been shown to be desirable. More specifically, bis(2,4-dicumylphenyl) pentaerythritol diphosphite exhibits excellent hydrolytic stability and comparable polymer stabilizing capability as compared to other pentaerythritol disphosphites.
It is further known to add secondary antioxidants to enhance the stabilizing capability of phosphites in polymers. For example, calcium stearoyl lactate in combination with bis(2,6-di-t-butyl-4-methylphenyI)pentaerythritol diphosphite has been shown to stabilize a polymer composition during extrusion of the composition. Other phosphites, such as bis(2,4-di-t-butyphenyl) pentaerythritol diphosphite have also been proposed for use with calcium stearoyl lactate and other metal lactate salts.
The excellent hydrolytic stability of bis(2,4-dicumylphenyl) pentaerythritol in diphosphite makes its use desirable. However, a need exists for a bis(2,4-dicumylphenyl) pentaerythritol diphosphite composition that exhibits superior polymer stabilizing capability.
It has now been found that a composition comprising bis(2,4-dicumylphenyl) pentaerythritol diphosphite and a metal salt of a lactic acid gives unexpectedly superior performance as a polymer stabilizer as compared with prior art compositions comprising other phosphites. As one indicator of the unexpectedly superior performance, a composition comprising bis(2,4-dicumylphenyl) pentaerythritol diphosphite and a metal
prepared and was labeled Blend F. A second dry blend of 500 parts Ultranox 626 (bis(2,4-di-t-butylphenyl) pentaerythnlol diphosphite) and 300 parts Pationic 1240 was prepared and was labeled Blend G. A third dry blend of 667 parts Doverphos S9228T (bis(2,4-dicumylphenyl) pentaerythritol diphosphite) and 300 parts Pationic 1240 (overbased calcium lactate) was prepared and was labeled Blend H. A fourth dry blend of 667 parts Ultranox 626 (bis(2,4-di-t-butylphenyl) pentaerythritol diphosphite) and 300 parts Pationic 1240 was prepared and was labeled Blend I. These blends were added to high density Pro fax 6501 polyethylene (Montell) powder along with the antioxidant Dovemox 10 tetrakis[methylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane) and the acid neutralizer zinc stearate. The polyethylene powder was then subjected to multiple pass extrusion at 260 ° C and 60 rpm using a Brabender Model PL 2000 single screw laboratory extruder. The extruded resin was then tested for changes in melt flow and color. The results are given in Table 2.
Lower melt flow and lower yellowness index values are desirable and indicate better stability during processing. The results show that while all the formulations F, G, H, and I provide comparably good melt flow stability, the formulations F and H using the blends with bis(2,4-dicumylphenyl) pentaerythritol diphosphite and a metal lactate salt provide significantly lower 5-pass yellowness index values as compared with blends G and I using bis(2,4-di-t-butylphenyl) pentaerythritol diphosphite and a metal lactate salt. This result is suprisingly unexpected.
The invention has been described with reference to several embodiments. Obviously, modifications and alterations will occur to others upon the reading and understanding of the specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof
What is claimed is:
1.A com position encable of stabilizing polymers, comprising;
bis(2,4-dimethyphenyl) pentaerythritol disphosphite; and at least one metal salt of a lactic acid.
.tris(3,5-di-t-butyl-4-hydroxybenzyl)-1,3,5-triazinw-2,4,6(111,311,511) trione, and) α-
17 The method of claim: 10, further comprising adding at least one hindered phenol antioxidant.
about 10 ppm to about 10,000ppm, based on the weight of the polymer composition..
21. A composition capable of stabilizing polymers substantially
as herein described and exemplified.
22. A method of stabilizing a polymer composition substantially
as herein described and exemplified.
|Indian Patent Application Number||102/MAS/2000|
|PG Journal Number||35/2007|
|Date of Filing||08-Feb-2000|
|Name of Patentee||M/S. DOVER CHEMICAL CORPORATION|
|Applicant Address||3676 DAVIS ROAD, N.W. DOVER, OH 44622 USA|
|PCT International Classification Number||C 08 K 5/04|
|PCT International Application Number||N/A|
|PCT International Filing date|