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US 11,447,622 B2Granted
Molding composition and articles formed thereof
AssigneeKraton Polymers LLC
InventorsVenkat Raghavendran, Kathryn Wright, Aaron Brothers
Life of this patent
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Abstract
Articles having improved properties are disclosed. The articles are formed from a composition obtained by dry blending: a) 70-95 wt. % of a polyolefin polymer selected from polypropylene homopolymers, polypropylene copolymers, polypropylene impact copolymers, and mixtures thereof; and b) 5 to 30 wt. % of a free-flowing styrenic block copolymer coated with a functional dusting agent having a maximum particle size of 100 microns. The free-flowing styrenic block copolymer requires less than 400 lbs/ft2 of force to break in a blocking test. The molded article has improved impact strength and haze.
Claims20
A molding composition comprising:
- 75 to 95 wt. % of a polyolefin polymer selected from polypropylene homopolymers, polypropylene copolymers, polypropylene impact copolymers, and mixtures thereof;
- and
- 5 to 25 wt. % of a styrenic block copolymer coated with a functional dusting agent having a maximum particle size of 100 microns, in an amount of less than 1 wt. % and at least 0.01 wt. %, based on total weight of the styrenic block copolymer,
- wherein the functional dusting agent is selected from modified sorbitols, benzoic acid salts, substituted benzoic acid salts, dicarboxylate metal salts, hexahydrophthalic acid metal salts, phenylphosphonic acid salts, phosphate ester salts, glycerolate salts, norbornane carboxylic acid salts, diamides, trisamides and derivatives thereof, tetramides, pine rosin derivatives, acetals and derivatives thereof, di-acetal derivatives, 2,6-naphthalene dicarboxamides, polyvinylcyclohexanes and combinations thereof;
- wherein the functional dusting agent is used to coat the styrenic block copolymer forming a coated styrenic block copolymer prior to mixing the coated styrenic block copolymer with the polyolefin polymer to form the molding composition;
- wherein the coated styrenic block copolymer is free-flowing, requiring a force of less than 400 lbs/ft2 to break in a blocking test;
- wherein a molded article comprising the molding composition has a notched Izod impact strength of at least 42 J/m, measured at 23° C. in accordance with ASTM D 256, and a haze value, measured according to ASTM D 1003, of 95% or lower.
4 more elements
A process for forming an article, comprising:
- a) providing a polyolefin polymer selected from polypropylene homopolymers, polypropylene copolymers, polypropylene impact copolymers, and mixtures thereof;
- b) providing a styrenic block copolymer;
- c) providing a functional dusting agent selected from modified sorbitols, benzoic acid salts, substituted benzoic acid salts, dicarboxylate metal salts, hexahydrophthalic acid metal salts, phenylphosphonic acid salts, phosphate ester salts, glycerolate salts, norbornane carboxylic acid salts, diamides, trisamides and derivatives thereof, tetramides, pine rosin derivatives, acetals and derivatives thereof, di-acetal derivatives, 2,6-naphthalene dicarboxamides, polyvinylcyclohexanes and combinations thereof, and wherein the functional dusting agent has a maximum particle size of 100 microns;
- d) coating the styrenic block copolymer with the functional dusting agent forming a coated styrenic block copolymer;
- e) mixing the coated styrenic block copolymer with the polyolefin polymer forming a molding composition;
- and
- f) forming an article from the molding composition;
- wherein the molding composition has 5 to 25 wt. % of the coated styrenic block copolymer and 75 to 95 wt. % of the polyolefin;
- wherein the functional dusting agent for coating the stytenic block copolymer is present in an amount of less than 1 wt. % and at least 0.01 wt. %, based on the weight of the styrenic block copolymer;
- wherein the coated styrenic block copolymer requires force of less than 400 lbs/ft2 to break in a blocking test,
- wherein the article has a notched Izod impact strength of 42 J/m or higher, measured at 23° C. in accordance with ASTM D256, and a haze value of 95% or lower.
8 more elements
Dependencies are inferred from the claim text.