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US 5,852,075 AGranted
Surfactant system for ink jet inks for printing on hydrophobic surfaces
AssigneeE. I. Du Pont de Nemours and Company
InventorRobert Paul Held
Life of this patent
Estimating the term…
Abstract
An ink for ink jet printers containing an aqueous carrier medium; a colorant; and a mixture of at least one siloxane surfactant; and at least one fluorinated surfactant exhibits excellent wetting on hydrophobic surfaces.
Claims10
An ink jet ink composition comprising:
- (a) an aqueous carrier medium;
- (b) a colorant comprising a pigment and a polymeric dispersant;
- and
- (c) 2.5 to 6%, based on the total weight of the ink composition, of a mixture of surfactants consisting essentially of
- (i) at least one siloxane surfactant selected from the group consisting of
- (1) a polyether modified siloxane of the formula:
- ##STR5## wherein R'=methyl;
- R"=hydrocarbon chain and R.sub.1 =H for ethylene oxide, CH.sub.3 for propylene oxide
- (2) a nonionic siloxane polyoxyalkylene copolymer, wherein each copolymer contains a siloxane polymer and at least one oxyalkylene polymer, comprising from 5% to 95% by weight of the block copolymer and having the general formula:
- (R')(SiO.sub.3).sub.x (R.sub.2 SiO).sub.y (C.sub.n H.sub.2n O).sub.z R"!.sub.a R'"!.sub.3x-a
- wherein R' is a hydrocarbon radical having a valence of x;
- R and R" are monovalent hydrocarbon radicals, R'" is a member of the group consisting of alkyl radicals and R.sub.2 Si-radicals;
- x.gtoreq.1;
- y.gtoreq.3;n=2-4;
- 1.gtoreq.a.ltoreq.3x and z.gtoreq.2,and
- (3) block copolymers composed of:
- (A) at least one siloxane unit represented by the formula:
- R.sub.b SiO.sub.(4-b)
- wherein R contains from one to about twenty-two carbon atoms inclusive and is selected from the class consisting of monovalent hydrocarbon groups and divalent hydrocarbon groups, and b has a value from 1 to 3 inclusive;
- said siloxane block containing at least one of said siloxane units wherein at least one R group is a divalent hydrocarbon group and
- (B) at least one oxyalkylene block containing at least two oxyalkylene groups represented by the formula:
- --R'O--
- wherein R' is an alkylene group containing from 2 to about 10 carbon atoms inclusive said siloxane and oxyalkylene blocks being interconnected by said divalent hydrocarbon group;
- (ii) at least one fluorinated surfactant of the formula:
- R(f)Q!.sub.n A
- wherein, R(f) is F(CF.sub.2 CF.sub.2).sub.3-8 ;
- Q is selected from the group consisting of CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 and CH.sub.2 CH.sub.2 ;
- A is a water soluble group selected from the group consisting of CO.sub.2 A;
- PO.sub.4 (A).sub.2 ;
- PO.sub.4 A and (OCH.sub.2 CH.sub.2).sub.x OH, where A is a counterion and x is 1-10;
- and n is 1 or 2;
- (iii) wherein the at least one siloxane surfactant is present in the amount of 15 to 75% by weight, based on the total weight of the surfactant mixture.
29 more elements
A process of printing an image on an untreated hydrophobic substrate comprising the step of ejecting an ink jet ink composition from an air brush sprayer onto a hydrophobic substrate, wherein said ink jet ink composition comprises:
- (a) an aqueous carrier medium;
- (b) a colorant comprising a pigment and a polymeric dispersant;
- and
- (c) 2.5 to 6%, based on the total weight of the ink composition, of a mixture of surfactants consisting essentially of
- (i) at least one siloxane surfactant selected from the group consisting of
- (1) a polyether modified siloxane of the formula:
- ##STR9## wherein R'=methyl;
- R"=hydrocarbon chain, and R.sub.1 =H for ethylene oxide, CH.sub.3 for propylene oxide
- (2) a nonionic siloxane polyoxyalkylene copolymer, wherein each copolymer contains a siloxane polymer and at least one oxyalkylene polymer, comprising from 5% to 95% by weight of the block copolymer and having the general formula:
- (R')(SiO.sub.3).sub.x (R.sub.2 SiO).sub.y (C.sub.n H.sub.2n O).sub.z R"!.sub.a R'"!.sub.3x-a
- wherein R' is a hydrocarbon radical having a valence of x;
- R and R" are monovalent hydrocarbon radicals, R'" is a member of the group consisting of alkyl radicals and R.sub.2 Si-radicals;
- x.gtoreq.1;
- y.gtoreq.3;n=2-4;
- 1.ltoreq.a.gtoreq.3x, and z.gtoreq.2;and
- (3) block copolymers composed of:
- (A) at least one siloxane unit represented by the formula:
- R.sub.b SiO.sub.(4-b)
- wherein R contains from one to about twenty-two carbon atoms inclusive and is selected from the class consisting of monovalent hydrocarbon groups and divalent hydrocarbon groups, and b has a value from 1 to 3 inclusive;
- said siloxane block containing at least one of said siloxane units wherein at least one R group is a divalent hydrocarbon group, and
- (B) at least one oxyalkylene block containing at least two oxyalkylene groups represented by the formula:
- --R'O--
- wherein R' is an alkylene group containing from 2 to about 10 carbon atoms inclusive, said siloxane and oxyalkylene blocks being interconnected by said divalent hydrocarbon group;
- (ii) at least one fluorinated surfactant of the formula:
- R(f)Q!.sub.n A
- wherein, R(f) is F(CF.sub.2 CF.sub.2).sub.3-8 ;
- Q is selected from the group consisting of CH.sub.2 CH.sub.2 SCH.sub.2 CH.sub.2 and CH.sub.2 CH.sub.2 ;
- A is a water soluble group selected from the group consisting of CO.sub.2 A;
- PO.sub.4 (A).sub.2 ;
- PO.sub.4 A;
- and (OCH.sub.2 CH.sub.2).sub.x OH, where A is a counterion and x is 1-10;
- and n is 1 or 2;
- (iii) wherein the at least one siloxane surfactant is present in the amount of 15 to 75% by weight, based on the total weight of the surfactant mixture.
30 more elements
Dependencies are inferred from the claim text.