Nucleating agents for thermoplastic resins
AssigneeE. I. Du Pont de Nemours and Company
InventorsMarlin D. Buckmaster, Stuart K. Randa
Life of this patent
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Abstract
This invention relates to the use of a special class of sulfonic and phosphonic acids, and salts of the acids, to give improved nucleation for foam extrusion of thermoplastics using either dissolved gas or chemical blowing agents to produce foam.
Claims42
Foamable, thermoplastic resin extrusion composition containing as a nucleating agent a nucleating-effective amount of at least one thermally stable compound which is selected from the group consisting of sulfonic and phosphonic acids and salts thereof.
Foamed structure produced by the improved process for producing a foam of a thermoplastic resin composition, the improvement characterized in that the process is carried out with a nucleating-effective amount of the nucleating agent of the formula
- [Z(CF.sub.2).sub.x (CF.sub.2 CFX).sub.p (R').sub.y (CH.sub.2).sub.z RO.sub.3 ].sub.n M
- wherein:
- the bivalent groups, except for RO.sub.3, may be present in any sequence;
- Z is CCl.sub.3, CCl.sub.2 H, H, F, Cl or Br;
- each X independently, is selected from H, F, Cl and CF.sub.3 ;
- R is sulfur or phosphorus;
- M is H or a metallic, ammonium, substituted ammonium or quaternary ammonium cation;
- x is an integer and is 0 to 20;
- p is an integer and is 0 to 6;
- y is 0 or 1;
- z is an integer and is 0 to 20;
- x+y+z+p is a positive integer or, if x+y+z +p is 0, Z is CCl.sub.3 or CCl.sub.2 H;
- n is the valence of M;
- and
- R' is selected from
- a C.sub.5-6 perfluorinated alicyclic ring diradical;
- a C.sub.1-16 perfluorinated aliphatic polyether diradical with repeat units selected from [CF.sub.2 O], [CF.sub.2 CF.sub.2 O], and [CF.sub.2 CF(CF.sub.3)O];
- and a substituted or unsubstituted aromatic diradical, in which case, z is H;
- so as to produce a foam having uniformity of cell size, small cell size, and high void content.
Dependencies are inferred from the claim text.