Damping thermoplastic elastomer blends exhibiting clarity
A thermoplastic elastomer compound includes polyester-type thermoplastic polyurethane and no greater than about 30 weight percent of styrene-isobutylene-styrene block copolymer. The compound has good clarity, as exhibited by a haze of no greater than about 60%, or 50%, or 30%, according to ASTM D 1003. Additionally, the compound has good damping properties, as exhibited by a resilience or vertical rebound of less than about 25% according to ASTM D2632.
1. A thermoplastic elastomer compound comprising:
(a) about 70 weight percent or more and no greater than about 90 weight percent, by weight of the compound, of polyester-type thermoplastic polyurethane; and
(b) about 10 weight percent or more and no greater than about 30 weight percent, by weight of the compound, of styrene-isobutylene-styrene block copolymer;
wherein the compound has a haze of no greater than about 60% when injection molded and tested at a thickness of 3 mm according to ASTM D1003,
wherein the compound has a vertical rebound of less than about 25% when injection molded and tested at a thickness of 3 mm according to ASTM D2632, and
wherein the compound is essentially free of styrenic block copolymer selected from the group consisting of styrene-ethylene/butylene-styrene block copolymer (SEBS), styrene-ethylene/propylene-styrene block copolymer (SEPS), styrene-ethylene/ethylene/propylene-styrene block copolymer (SEEPS), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), and combinations thereof.
2. The compound of claim 1 , wherein the compound has a haze ranging from about 20% to about 30% when injection molded and tested at a thickness of 3 mm according to ASTM D1003.
3. The compound of claim 1 , wherein the compound has a Shore A hardness of less than about 83 when tested with a 10 second delay according to ASTM D2240.
4. The compound of claim 1 , wherein the compound further comprises at least one additive selected from the group consisting of adhesion promoters; antioxidants; biocides; anti-fogging agents; anti-static agents; blowing and foaming agents; bonding agents and bonding polymers; dispersants; flame retardants and smoke suppressants; impact modifiers; initiators; lubricants; micas; pigments, colorants and dyes; plasticizers, processing aids; release agents; silanes, titanates and zirconates; slip and anti-blocking agents; stabilizers; stearates; ultraviolet light absorbers; viscosity regulators; waxes; and combinations thereof.
5. The compound of claim 1 , wherein the compound comprises:
(a) from about 80 to about 90 weight percent, by weight of the compound, of polyester-type thermoplastic polyurethane;
(b) from about 10 to about 20 weight percent, by weight of the compound, of styrene-isobutylene-styrene block copolymer; and
(c) from about 0.1 to about 0.5 weight percent, by weight of the compound, of one or more additives selected from the group consisting of antioxidants, waxes, and combinations thereof.
6. The compound of claim 1 , wherein the polyester-type thermoplastic polyurethane is a reaction product of reactants comprising polyester polyol and diisocyanate and, optionally, chain extender.
7. The compound of claim 1 , wherein the compound is essentially free of polyether-type polyurethane.
8. The compound of claim 1 , wherein the compound is essentially free of high softening point tackifier.
9. The compound of claim 1 , wherein the compound consists of:
(a) from about 80 to about 90 weight percent, by weight of the compound, of polyester-type thermoplastic polyurethane;
(b) from about 10 to about 20 weight percent, by weight of the compound, of styrene-isobutylene-styrene block copolymer; and
(c) from about 0.1 to about 0.5 weight percent, by weight of the compound, of one or more additives selected from the group consisting of antioxidants, waxes, and combinations thereof.
10. A plastic article formed from the compound of claim 1 .
11. The article of claim 10 , wherein the article is a molded article, an extruded article, a thermoformed article, a laminated article, a calendered article, or an additive 3-D printed article.