Additive composition and process for using the same

Abstract

An additive composition comprises a wax and a nucleating agent. The nucleating agent can be dispersed in the wax. A process for producing a nucleated polymer comprises the steps of (a) providing a reactor; (b) providing an additive composition comprising a wax and a nucleating agent; (c) providing an extruder; (d) reacting in the reactor a reactant mixture comprising an olefin monomer and hydrogen to produce a polyolefin polymer; (e) collecting and recovering the polyolefin polymer produced by the reaction; (f) conveying the polyolefin polymer to the extruder; (g) conveying the additive composition to the extruder; and (g) extruding the polyolefin polymer and the additive composition to produce a nucleated polymer composition.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims, pursuant to 35 U.S.C. §119(e), the benefit of the filing date of U.S. Patent Application No. 61 / 740,588, which was filed on Dec. 21, 2012.TECHNICAL FIELD OF THE INVENTION[0002]This application relates to additive compositions and processes for producing a nucleated polymer composition.BACKGROUND[0003]Several nucleating agents for thermoplastic polymers are known in the art. These nucleating agents generally function by forming nuclei or providing sites for the formation and / or growth of crystals in the thermoplastic polymer as it solidifies from a molten state. The nuclei or sites provided by the nucleating agent allow the crystals to form within the cooling polymer at a higher temperature and / or at a more rapid rate than the crystals will form in the virgin, non-nucleated thermoplastic polymer. These effects can then permit processing of a nucleated thermoplastic polymer composition at cycle times that are shorte...

AI Technical Summary

Benefits of technology

The invention provides a way to make polyolefin polymers that have nucleating agents evenly distributed throughout. This is important because nucleating agents help improve the performance and efficiency of polymers. The process involves using an additive composition made of a wax and the nucleating agent. This additive can be fed into the manufacturing process as a solid or a liquid. This process makes it easier to create high-quality nucleated polymers.

Problems solved by technology

While there are many benefits associated with the use of nucleating agents in thermoplastics, there are some difficulties associated with their use.

However, it can be difficult to adequately disperse the nucleating agent in the polymer using the equipment available during the polymer manufacturing process.

For example, many polymer manufacturing operations do not have dispersive mixing capabilities in their extrusion process that can adequately disperse a powdered nucleating in the manufactured polymer.

Accordingly, resin manufacturers have resorted to the use of masterbatch compositions to incorporate nucleating agents, which is a procedure that can be costly and complex as discussed below.

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