Pre-processed thermoplastic compound
View Patent ↗A pre-processed polymer composite is disclosed comprising a heat-sensitive polymer resin particle; particles of colorant or functional additive in association with the heat-sensitive polymer resin particle; and a thermoplastic encapsulant to form a film around the associated polymer and colorant or functional additive particles. The method of making the polymer composite avoids a melting of the heat-sensitive polymer resin particles, which avoids contributing to heat history of the polymer prior to extrusion or molding into the form of the final plastic article.
1. A polymer composite, comprising:
(a) heat-sensitive polymer resin particles;
(b) particles of colorant or functional additive or both in association with the heat-sensitive polymer resin particles; and
(c) a thermoplastic encapsulant to form a film around the associated polymer resin particles and colorant or additive particles,
wherein the heat-sensitive polymer resin particles have a particle size ranging from about 500 to about 5,000 microns,
wherein the colorant can have a particle size ranging from about 0.01 to about 10,000 microns,
wherein the particles of heat-sensitive polymer resin particles and the particles of colorant or additive or both are affiliated as clusters of a discontinuous phase in a continuous phase of the thermoplastic encapsulant, and
wherein the thermoplastic encapsulant has a solids content and is an emulsion of a styrene/acrylate copolymer or an aqueous dispersion of a biopolymer, wherein the solids content of the emulsion or the dispersion ranges from about 20 to about 60 weight percent.
2. The composite of claim 1 , wherein the heat-sensitive polymer resin is selected from the group consisting of polyphenylene sulfide (PPS); polylactic acid (PLA); polycarbonate (PC); polyethylene terephthalate (PET); polybutylene terephthalate (PBT); acrylonitrile butadiene styrene (ABS) and combinations thereof.
3. The composite of claim 1 , wherein the heat-sensitive polymer resin has a weight average molecular weight ranging from about 3000 to about 3×10 6 .
4. The composite of claim 1 , wherein the heat-sensitive polymer resin has a glass transition temperature ranging from about −30 to about 300° C.
5. The composite of claim 1 , wherein the colorant comprises a pigment, a dye, a combination of pigments, a combination of dyes, a combination of pigments and dye, a combination of pigment and dyes, or a combination of pigments and dyes.
6. The composite of claim 1 , wherein the colorant is organic or inorganic.
7. The composite of claim 1 , wherein the thermoplastic encapsulant can be a solvent-based liquid emulsion or a solution of film-forming polymer.
8. The composite of claim 1 , wherein the thermoplastic encapsulant is translucent or transparent in the visible spectrum.
9. The composite of claim 1 , wherein the functional additive is selected from the group consisting of anti-oxidants, anti-stats, acetaldehyde scavengers, blowing agents, surfactants, biocides, exfoliated nanoclays, ultraviolet stabilizers, and combinations of them.
10. The composite of claim 1 , wherein the composite further comprises optional special effect features selected from the group consisting of granite, translucent, pearls, metallics, fluorescents, iridescents, marbles, and combinations of them.
11. The composite of claim 1 , wherein heat-sensitive polymer resin particles comprise from about 40 to about 99 weight percent of the composite, wherein the colorant particles or additive particles or both comprise from about 0.0001 to about 10 weight percent of the composite, and wherein the thermoplastic encapsulant solids content comprises from about 0.1 to about 5 weight percent of the composite.
12. A method of making a polymer composite of claim 1 , comprising the steps of
(a) mixing heat-sensitive polymer resin particles and particles of colorant, additive, or both at a temperature below the melting point of the polymer resin particles to form a dry blend of mixed particles; and
(b) mixing the dry blend of particles with a thermoplastic encapsulant at a temperature below the melting point of the polymer resin particles to form an encapsulated, dry blended particle mixture.
13. The method of claim 12 , further comprising step (c) of drying the encapsulated dry blended particle mixture at a temperature below the melting point of the polymer resin particles.
14. The method of claim 13 ,
wherein the mixing of both steps (a) and (b) comprises agitation in a range of from about 10 rpm to about 1000 rpm for mixing times ranging from about 1 to about 30 minutes and
wherein the drying of step (c) ranges in temperature from about 20° C. to about 50° C.