Moldable engineered stone
AssigneeSafas Corporation
InventorYifang Zhao
Life of this patent
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Abstract
This invention provides a moldable engineered stone composition comprising an ethylenically unsaturated acrylic polymer capable of being covalently crosslinked, a mineral particulate, and an ionic crosslinking agent which forms ionic bonds within the syrup of unsaturated acrylic polymer via unreacted acid groups, causing thickening prior to curing and prior to the formation of covalent bonds via the double bonds of the polymer chain. The composition is then capable of being extruded and molded in a press. Articles formed by curing the composition and methods for producing the composition are also disclosed.
Claims13
A moldable engineered stone composition, comprising:
- (a) 15 to 20% by weight of the composition of a matrix resin comprising a syrup of an unsaturated acrylic polymer containing from 1 to 10% by weight of the polymer of an acrylic carboxylic acid copolymerized with monounsaturated esters and having unreacted acid groups, and from 1 to 5% by weight of the polymer of a crosslinking acrylic monomer,
- (b) from 80 to 85% by weight of the composition of a mineral particulate,
- (c) from 0.20 to 5% by weight of the composition of an ionic crosslinking agent, said ionic crosslinking agent forming ionic bonds with said unreacted acid groups, said ionic bonds causing a thickening prior to covalent crosslinking, and
- (d) a free radical polymerization initiator.
A method of preparing a molded engineered stone composition which comprises:
- (i) forming a composition of:
- (a) from 15 to 20% by weight of the composition of an unsaturated acrylic polymer in the form of a syrup, containing from 1 to 10% by weight of the acrylic polymer of an acrylic carboxylic acid copolymerized with monounsaturated esters and having unreacted acid groups, and from 1 to 5% by weight of the acrylic polymer of a crosslinking acrylic monomer,
- (b) from 80 to 85% by weight of the composition of a mineral particulate,
- (c) from 0.25 to 0.5% by weight of the composition of an ionic crosslinking agent, and
- (d) a free radical polymerization initiator,
- (ii) forming such composition into a sheet,
- (iii) allowing the viscosity of the sheet to increase until the sheet has been solidified, said viscosity increasing via a formation of ionic bonds between said ionic crosslinking agent and said unreacted acid groups, and
- (iv) molding the sheet into a formed article at elevated temperatures to cause curing of the molded article.
Dependencies are inferred from the claim text.