Method and composition re polyurethane seating
This invention relates to a coating comprising prepolymer and monomers for application onto polyurethane for chemical resistance, abrasion resistance, water proof etc. Usually polyurethane is porous and does not have sufficient stain, abrasion and chemical resistance. The said coatings developed using technology of chemical grafting that involves the use of prepolymers, monomers, catalyst, graft initiator, wetting agents, fillers and other ingredients of the composition. The coating thus obtained when applied on the polyurethane allows obtaining graft polymerization, thereby forming a polymeric film chemically attached to the substrate. The polyurethane substrate is reacted with graft initiator which creates the reaction sites on the substrate via free radical mechanism. This in turn renders the substrate receptive to attachment of monomers/prepolymers forming polymeric film that is chemically bonded to the substrate which has then the desired property in terms of stain resistance, abrasion wear, crock, water, chemical resistance and other properties.
1. A method of grafting a coating onto a substrate selected from the group consisting of a chair, arm rests, beds, mats, commodes, mattresses and cushions comprising:
(a) spraying an admixture of prepolymers and monomers onto the substrate in a graft solution including water, a graft initiator in an amount of about 0.001% to about 0.01% by weight of the solution, and a catalyst in an amount of 0.001% to 0.01% by weight of the solution;
(b) wherein said graft solution comprises from 40 to 50 percent solids in an aqueous solution; and
(c) drying said sprayed admixture for about 10 to 15 minutes and curing the sprayed admixture at 125 to 150 degrees centigrade for about 5 to 10 minutes.
2. A method according to claim 1 wherein said substrate includes a seam.
3. A method according to claim 1 wherein said admixture comprises a first component that has a functional group for reaction and covalent bonding with an active site for the substrate.
4. A method according to claim 3 wherein the first component is a water dispersible polymer.
5. A method according to claim 4 wherein said water dispersible polymer comprises an epoxy prepolymer, a urethane prepolymer, and acrylic prepolymer.
6. A method according to claim 5 wherein said water dispersible polymer includes at least one functional group selected from a carboxyl, hydroxyl, epoxy, amino, melamine, and acrylic group.
7. A method according to claim 6 wherein said monomers are acrylate, methacrylate or urethane acrylate.
8. A method according to claim 6 wherein said graft initiators comprise metallic salts.
9. A method according to claims wherein said metal salts comprise silver nitrate, silver perchlorate, ferrous ammonium sulphate, or silver acetate.
10. A method according to claim 9 wherein said catalyst ionizes the metal salts to provide activating metal ions and said substrate includes brackets or clips which are sprayed with the admixture.
11. A method according to claim 10 wherein said catalyst is a peroxide of urea, hydrogen, benzoyl or an admixture thereof.
12. A method according to claim 11 wherein said catalyst ionizes the metal salts into silver and iron or other metals.
13. A method according to claim 1 wherein said graft solution comprises:
PART BY WEIGHT
NAME OF CHEMICAL
OF THE SOLUTION
Polyurethane prepolymer
200.00
Urethane prepolymer
100.00
Finely micronized poly
30.00
tetra fluro ethylene
Polyaziridine
10.00
Deionised water
100.00
Urethane acrylate
0.50
Monomer coatosil 1770
0.20
(β-(3,4-epoxycyclohexyl)
ethyltriethoxysilane)
Cationic carbon 6 based fluoro polymer
20.00
Poly tetra fluoro ethylene emulsion 298
10.00
Urea peroxide 1.0% solution in water
0.10
Silver perchlorate 0.1% solution in water
0.10.
14. A method according to claim 1 wherein the substrate is either polyurethane, vinyl or nylon.
15. A method according to claim 1 wherein said graft solution comprises:
PART BY WEIGHT
NAME OF CHEMICAL
OF THE SOLUTION
D. B. Solvent
60.00
Monomer coatosil 1770
0.20
(β-(3,4-epoxycyclohexyl)
ethyltriethoxysilane)
Surfactant
2.00
Fluro polymer emulsion
500.00
consisting of alternating
fluoroethylene and alkyl
vinyl ether segments
Silica disperson comprising silica,
150.00
amorphous, precipitated and gel
25-50% weight %; 5-Decyne-
4,7-diol, 2,4,7,9-tetramethyl < 2.5%
weight %; polyethylene glycol
branced nonyl phenyl ether < 2.5%
weight %
Deionised water
300.00
Polyisocyanate DA
40.00
Monomer sodium vinyl sulfonate
1.00
Urea peroxide 1.0% in water
1.00
Silver perchlorate 0.1% in water
0.20.
16. A method of grafting a coating onto a substrate selected from the group consisting of a chair, arm rests, beds, mats, commodes, mattresses and cushions, the method comprising:
(a) applying an admixture of prepolymers and monomers onto the substrate in a graft solution including water, a graft initiator in an amount of about 0.001% to about 0.01% by weight of the solution, and a catalyst in an amount of 0.001% to 0.01% by weight of the solution: wherein said admixture comprises a first component that has a functional group for reaction and covalent bonding with an active site for the substrate;
(b) wherein said graft solution comprises from 40 to 60 percent solids in an aqueous solution
wherein the step of applying said admixture onto said substrate is spraying, wherein the method further comprises drying said sprayed admixture for about 10 to 15 minutes and curing the sprayed admixture at 125 to 150 degrees centigrade for about 5 to 10 minutes.