Additive package for thermoplastic condensation polymers
View Patent ↗The invention is directed to a thermoplastic condensation polymer chain extender additive package for reducing the molecular weight loss of a thermoplastic condensation polymer during a heated process comprising a chain extender composition selected from the group consisting of (a) a mixture of a chain extending agent and a water-bearing particulate material (b) a water-bearing particulate material surface treated with a chain extending agent or (c) a combination of (a) and (b). The water-bearing particulate material can be titanium dioxide pigment, the chain extending agent can be a multifunctional epoxy compound and the condensation polymer can be polyethylene terephthalate, polybutylene terephthalate or polycarbonate.
1. A method for forming a thermoplastic condensation polymer susceptible to molecular weight loss during a heated process, comprising:
metering a liquid composition comprising a chain extending agent into a flow restrictor and injecting a gas stream through the flow restrictor to create a zone of turbulence at the outlet of the flow restrictor thereby atomizing the liquid composition and adding a water-bearing particulate material to the zone of turbulence concurrently with metering of the liquid composition and the injection of the gas to mix the particulate material with the atomized liquid composition to form a chain extender composition;
introducing the thermoplastic condensation polymer to an extruder;
adding to the thermoplastic condensation polymer the chain extender composition; and
heat processing the thermoplastic condensation polymer in the extruder, wherein adding the chain extender composition reduces molecular weight loss of the thermoplastic condensation polymer during the heat processing.
2. The method of claim 1 further comprising pelletizing the condensation polymer after heat processing.
3. The method of claim 1 further comprising adding the heat processed condensation polymer as a masterbatch into a thermoplastic melt.
4. The method of claim 1 further comprising forming the condensation polymer into a container, fiber or film.
5. The method of claim 1 in which the thermoplastic condensation polymer is selected from the group consisting of vinyl acetate; polyvinyl ester, amino resin; polyamide; polyamideimide; polyetherimide; polyurethane; polycarbonate; polyester; polyphenylene oxides; amino resins; and combinations thereof.
6. The method of claim 1 in which the water-bearing particulate material is titanium dioxide.
7. The method of claim 1 in which the chain extending agent is selected from the group consisting of an epoxy compound, acrylic acid-derived polymer and copolymer, methacrylic acid-derived polymer and copolymer, polyol, multifunctional acid anhydride, polyacid, polyamine, isocyanate, phosphate ester, aziridine, oxazoline, multivalent metal compound wherein the metal has a valence of not less than 2, phosphite ester and combinations thereof.
8. The method of claim 1 in which chain extending agent is selected from the group consisting of a reaction product of epichlorohydrin and bisphenol-A, a tetraglycidyl ether of tetraphenolethane and an epoxy-modified styrene acrylic polymer and combinations thereof.