Melt spinable concentrate pellets having enhanced reversible thermal properties
View Patent ↗A process for manufacturing extrudable/melt spinnable concentrate pellets which contain phase change materials (PCMs), whether the PCMs are micro-encapsulated absorbed into carrier polymers, or non-micro-encapsulated within the concentrate pellets. The polymer matrix within the concentrate pellets can be any thermoplastic polymer or combination of thermoplastic polymers, and the concentrate pellets can then be blended into similar thermoplastic polymers to form mono-filament melt spun fibers, extruded films, injection molded products, etc., or the concentrate pellets can be blended with other thermoplastic polymers to form bi-component or multi-component melt spun fibers, extruded films, injection molded products, etc.
1. A method of manufacturing polymer-based pellets useful in extrusion and melt spin manufacturing processes to form plastic articles, comprising the steps of:
providing at least one water-based phase change material;
providing a low molecular weight polymer having an affinity for the phase change material;
providing a high molecular weight polymer having an affinity for the low molecular weight polymer and having physical characteristics compatible with an intended use of the plastic articles;
melting the low molecular weight polymer to form a first melt;
uniformly blending the phase change material into the first melt to form a first blend;
cooling the first blend to form a first solid;
processing the first solid to form granules;
melting the high molecular weight polymer to form a second melt;
uniformly blending the granules into the second melt to form a second blend;
cooling the second blend to form a second solid; and
processing the second solid to form the polymer-based pellets.
2. The method of claim 1 wherein said polymer-based pellets each contain from about 10 to about 30 weight percent of said phase change material.
3. The method of claim 1 wherein said low molecular weight polymer is selected from the group homopolymers of polyethylene, polypropylene, Nylon 12, polybutylene terephthalate, and copolymers of polyethylene-co-vinyl acetate, polyethylene-co-acrylic acid, polybutylene terphthalate-co-polytetramethylene terephthalate, and polylauryllactam-block-polytetrahydrofuran; and said high molecular weight polymer is selected from the group polyamides, polyamines, polyimides, polyacrylics, polycarbonates, polydienes, polyepoxides, polyesters, polyethers, polyflourocarbons, formaldehyde polymers, natural polymers, polyolefins, polyphenylenes, silicon containing polymers, polyurethanes, polyvinyls, polyacetals, and polyarylates.
4. The method of claim 1 wherein said phase change material is an encapsulated phase change material.
5. The method of claim 1 wherein said phase change material is physically confined to a plurality of physical volumes by the addition of a material selected from the group silica, fumed silica and zeolite.
6. The method of claim 1 wherein said step of processing said first-solid and said step of processing said second-solid each include an extrusion step.
7. The method of claim 1 wherein said step of adding said phase change material to said first-melt includes adding a wetcake of said phase change material to said first-melt, and including the step of heating said fir melt until a water content of said first-melt is reduced to at least about 0.15 weight percent.
8. The method of claim 7 wherein said polymer-based pellets each contain from about 15 to about 25 weight percent of said phase change material.
9. The method of claim 1 wherein said phase change material is micro encapsulated within a plurality of hollow shells, and wherein said low molecular weight polymer includes a polymer-constituent having an affinity for material forming said hollow shells.
10. The method of claim 1 wherein said phase change material is encased in a plurality of nylon shells and wherein said low molecular weight polymer includes a nylon constituent.