Nucleating Agents
“Nucleating agents are added to provide the user with some degree of control over this initiation of crystallization; the addition of a nucleating agent to a polymer melt results, on cooling, in the appearance of a substantial increase in heterogeneous nucleation and thus a reduction in the size of crystalline structures.” [Fairgrieve, Nucleating Agents Report:9 (2007) 3/14/2011]
“Typical nucleating agents known in the art include minerals, such as chalk, clay, kaolin, talc, silicates, and the like. Organic nucleating agents, such as salts of aliphatic or aromatic carboxylic acids, aromatic salts, metallic salts of aromatic phosphorus compounds, quinaridones, aromatic amides, and polymers having melting points are more efficient.” (Ma et al, Chemtura Corporation, US Patent 7,569.630, 8/4/2009)
“Nucleating and clarifying agents are chemical compositions that may be added to thermoplastic polymers to facilitate formation of the polymer as it changes from molten to solid form in the process of crystallization. Such additives may assist in reducing haze of polymeric structures. Many different chemical compositions are known for this purpose. One major issue in the use of such agents is the amount or degree of clarity that the agent or additive imparts to a finished polymeric article. Reducing haze and thereby increasing clarity of such articles is a constant endeavor in the plastics industry.”
“In general, the use of nucleating agents is a highly unpredictable technology area. Small or slight changes in a molecular structure can drastically change the ability of a given nucleating composition to nucleate or clarify effectively a polymer composition. There is a large amount of unpredictability in the art of nucleating agents. There are many unknowns regarding the effect of a given substance on polymer morphology during recrystallization of thermoplastics.”
[Hanseen, US Patent 7,879,933 (2/1/2011)]
Compounding
Polylactic Acid (PLA) Nucleating Agents
Polypropylene (PP) Nucleating Agents
Super-Nucleators
Recent US Patents
9/27/2011
8,026,305
Articles formed from nucleated polyethylene
A linear polyethylene formed by metallocene catalysis has been developed as a nucleation agent for crystalline polymers with improved clarity and deformability. (RDC 10/3/2011)
2/1/2011
7,879,933
Blended nucleating agent compositions and methods
Hanseen of Milliken & Company, South Carolina,have devlope a blended nucleating agent consisting of combinations of a phosphate salt and a dicarboxylate salt. This combination or blend may be provided in various ratios. (RDC 8/17/2011)