Heat resistant, flame retardant polylactic acid compounds
View Patent ↗Significant disadvantages of the use of polylactic acid (PLA), lack of good heat stability and flame retardance, have been overcome by the use of resorcinol bis(diphenyl phosphate) in combination with talc. The compound achieves a threshold of 65° C. in heat deflection temperature and V-0 flame retardance at 1.6 mm thickness.
1. A heat resistant, flame retardant, polylactic acid compound, comprising:
(a) polylactic acid in an amount from about 30 to about 35 weight percent of the compound;
(b) polycarbonate in an amount from about 50 to about 60 weight percent of the compound;
(c) talc in an amount from about 2 to about 5 weight percent of the compound; and
(d) resorcinol bis (diphenyl phosphate) in an amount from about 10 to about 13 weight percent of the compound;
wherein the compound has a heat distortion temperature of greater than 75 degrees C. when tested according to ASTM D-648 at 66 PSI; and
wherein the compound has a V-0 rating when tested according to ASTM Test No. D-635 at both 3.2 mm and 1.6 mm thicknesses.
2. The compound of claim 1 , wherein an acrylic impact modifier is present in an amount of from about 1 to about 15 weight percent of the compound.
3. The compound of claim 1 , wherein the polylactic acid comprises poly-D-lactide, poly-L-lactide, or a combination of both.
4. The compound of claim 2 , wherein the impact modifier is a core/shell acrylic polymer.
5. The compound of claim 1 , further comprising one or more optional additives selected from the group consisting of adhesion promoters; biocides; anti-fogging agents; anti-static agents; bonding, blowing and foaming agents; dispersants; initiators; lubricants; pigments, colorants and dyes; plasticizers; processing aids; release agents; slip and anti-blocking agents; stabilizers; stearates; ultraviolet light absorbers; viscosity regulators; waxes; and combinations of them.
6. A plastic article shaped from a compound of claim 1 .
7. The article of claim 6 , wherein the article is molded or extruded and wherein the article is shaped for use in transportation, appliance, electronics, building and construction, packaging, or consumer markets.
8. A method of making the compound of claim 1 , comprising the steps of
(a) gathering ingredients including polylactic acid, polycarbonate, talc, and resorcinol bis (diphenyl phosphate),
(b) melt-mixing them into a compound.
9. The article of claim 7 , wherein before molding or extrusion the compound has been dried to a moisture content of less than 0.2%.