Crosslinked rubber/resin binders for chromium dioxide recording members

Claim 2

IN A MAGNETIC RECORDING COMPOSITION OF THE TYPE COMPRISING A PLURALITY OF FERROMAGNETIC CHROMIUM DIOXIDE PARTICLES DISPERSED IN A POLYMERIC RESN BINDER, THE IMPROVEMENT WHEREIN SAID BINDER IS FORMED BY THE REACTON OF A POLYOL AND A POLYFUNCTIONAL HYDROXYL-REACTIVE COMPOUND IN THE PRESENCE OF A PERFORMED ELASTOMER AND A PREFORMED HARD RESIN; SAID POLYOL BEING SELECTED FROM THE GROUP CONSISTING OF LINEAR OR BRANCHED ALIPHATIC DIOLS AND TRIOLS, POLYMERIC CARBOXYLIC ESTERS HAVING A MOLECULAR WEIGHT GREATER THAN 200 AND HYDROXYL NUMBERS IN THE RAGE OF 1 TO 500, AND ADDITION POLYMERS HAVING AVAILABLE PENDANT REACTIVE HYDROXYL GROUPS; SAID PREFORMED ELASTOMERS BEING SELECTED FROM THE GROUP CONSISTING OF NATURAL RUBBER, BUTADIENE/ACRYLONITRILE COPOLYMERS; BLOCK COPOLYMERS OF BUTADIENE/STYRENE; POLYCHLOROPRENE; CHLOROSULFONATED POLYETHYLENE; AND PERFORMED NON-REACTIVE POLYETHERPOLYURETHANES AND POLYESTERPOLYURETHANES; AND SAID PREFORMED HARD RESIN BEING SELECTED FROM THE GROUP CONSISTING OF EPOXY AND PHENOXY RESINS, POLYCARBONATES; POLYESTER; POLYACRYLIC AND POLYMETHACRYLIC ACIDS AND ESTERS THEREOF, CELLULOSE ETHERS AND ESTER, STYRENE POLYMERS AND COPOLYMERS, POLYAMIDES, VINYL POLYMERS AND COPOLYMERS, VINYLIDENE POLYMERS AND COPOLYMER, COPOLYMERS OF TWO OR MORE VINYL, VINYLIDENE OR ACRYLIC MONOMERS AND MIXTURES THEREOF; THE TOTAL BINDER COMPOSITION COMPRISING 1 TO 25% BY WEIGHT OF POLYOL, 2.5 TO 30% BY WEIGHT OF POLYFUNCTIONAL HYDROXYL-REACTIVE COMPOUNDS, 10 TO 60% BY WEIGHT OF PERFORMED ELASTOMERS AND 25 TO 70% BY WEIGHT OF PERFORMED HARD RESIN.

Claim 3

The magnetic recording composition of claim 1 wherein said preformed elastomer is a preformed, nonreactive polyurethane.

Claim 4

The magnetic recording composition of claim 2 wherein said preformed, nonreactive polyurethane is selected from the group consisting of polyesterpolyurethane and polyetherpolyurethane elastomers.

Claim 5

The magnetic recording composition of claim 2 wherein said preformed, nonreactive polyurethane is an organosoluble polyesterpolyurethane based on diphenylmethane diisocyanate, adipic acid and an alkanediol having 2-4 carbon atoms or mixtures of such alkanediols.

Claim 6

The magnetic recording composition of claim 1 wherein said preformed hard resin is a nonelastomeric, macromolecular film forming organic polymer selected from the group consisting of vinylidene chloride/acrylonitrile and vinyl chloride/vinyl acetate copolymers.

Claim 7

The magnetic recording composition of claim 1 wherein said binder contains from about 3.5 to about 55% by weight of said reaction product.

Claim 8

The magnetic recording composition of claim 6 wherein said polyol is selected from the group consisting of linear or branched aliphatic diols and triols, polymeric carboxylic esters, and addition polymers having available pendant reactive hydroxyl groups.

Claim 9

The magnetic recording composition of claim 6 wherein said polyfunctional hydroxyl-reactive compound is a polyfunctional isocyanate.

Claim 10

The magnetic recording composition of claim 8 wherein said polyfunctional isocyanate is selected from the group consisting of hexamethylene diisocyanate, diphenyl-methane diisocyanate, diphenylmethane triisocyanate, toluene diisocyanate, polyethylene polyphenylisocyanate, the C36 diisocyanate from linoleic dimer acids, 4,4''-methylene-bis-(cyclohexylisocyanate), and the product of 2,4-toluene diisocyanate and trimethylolpropane reacted in a ratio in the range of about 3 to 1 to about 5 to 2.

Claim 11

The magnetic recording composition of claim 1 wherein said binder comprises about 15 to about 40% by weight of said preformed elastomer, about 30 to about 60% by weight of said preformed hard resin and about 5 to about 40% by weight of said reaction product.

Claim 12

The magnetic recording composition of claim 10 wherein said preformed elastomer comprises an organosoluble polyesterpolyurethane resin based on diphenylmethane diisocyanate, adipic acid and an alkanediol having 2-4 carbon atoms or mixtures of said alkanediols; said preformed hard resin is selected from the group consisting of vinylidene chloride/acrylonitrile and vinyl chloride/vinyl acetate copolymers; said polyol is a polymeric carboxylic ester; said polyfunctional hydroxyl-reactive compound is the product of 2,4-toluene diisocyanate and trimethylolpropane reacted in a ratio in the range of about 3 to 1 to about 5 to 2; and said ferromagnetic particles are particles of acicular chromium dioxide.

Claim 13

In a process for making a magnetic composition of the type comprising admixing about 1 to about 98% by weight of ferromagnetic chromium dioxide particles with about 2 to about 99% by weight of a binder composition, the improvement wherein said ferromagnetic chromium dioxide particles are mixed with a mixture of a preformed elastomer, a preformed hard resin, a polyol and a polyfunctional hydroxyl-reactive compound in a manner such that said polyol and said polyfunctional hydroxyl-reactive compound react to form a reaction product after their admixture with the other ingredients; said polyol being selected from the group consisting of linear or branched aliphatic ciols and triols, polymeric carboxylic esters having a molecular weight greater than 200 and hydroxyl numbers in the range of 1 to 500, and addition polymers having available pendant reactive hydroxyl groups; said preformed elastomers being selected from the group consisting of natural rubber, butadiene/acrylonitrile copolymers; block copolymers of butadiene/styrene; polychloroprene; chlorosulfonated polyethylene; and preformed non-reactive polyetherpolyurethanes and polyesterpolyurethanes; and said preformed hard resin being selected from the group consisting of epoxy and phenoxy resins, polycarbonates; polyesters; polyacrylic and polymethacrylic acids and esters thereof, cellulose ethers and esters, styrene polymers and copolymers, polyamides, vinyl polymers and copolymers, vinylidene polymers and copolymers, copolymers of two or more vinyl, vinylidene or acrylic monomers and mixtures thereof; the total binder composition comprising 1 to 25% by weight of polyol, 2.5 to 30% by weight of polyfunctional hydroxyl-reactive compounds, 10 to 60% by weight of preformed elastomers and 25 to 70% by weight of preformed hard resin.

Claim 14

In a process for making a magnetic composition of the type comprising admixing about 1 to about 98% by weight of ferromagnetic chromium dioxide particles with about 2 to about 99% by weight of a binder composition, the improvement wherein said ferromagnetic chromium dioxide particles are mixed with a mixture of a preformed elastomer, a preformed hard resin, a polyol and a polyfunctional hydroxyl-reactive compound in a manner such that said polyol and said polyfunctional hydroxyl-reactive compound react to form a reaction product after their admixture with the other ingredients; said polyol being selected from the group consisting of linear or branched aliphatic ciols and triols, polymeric carboxylic esters having a molecular weight greater than 200 and hydroxyl numbers in the range of 1 to 500, and addition polymers having available pendant reactive hydroxyl groups; said preformed elastomers being selected from the group consisting of natural rubber, butadiene/acrylonitrile copolymers; block copolymers of butadiene/styrene; polychloroprene; chlorosulfonated polyethylene; and preformed non-reactive polyetherpolyurethanes and polyesterpolyurethanes; and said preformed hard resin being selected from the group consisting of epoxy and phenoxy resins, polycarbonates; polyesters; polyacrylic and polymethacrylic acids and esters thereof, cellulose ethers and esters, styrene polymers and copolymers, polyamides, vinyl polymers and copolymers, vinylidene polymers and copolymers, copolymers of two or more vinyl, vinylidene or acrylic monomers and mixtures thereof; the total binder composition comprising 1 to 25% by weight of polyol, 2.5 to 30% by weight of polyfunctional hydroxyl-reactive compounds, 10 to 60% by weight of preformed elastomers and 25 to 70% by weight of preformed hard resin.

Claim 15

The process of claim 12 wherein said preformed elastomer is a preformed, nonreactive polyurethane.

Claim 16

The process of claim 13 wherein said preformed, nonreactive polyurethane is selected from the group consisting of polyesterpolyurethane and polyetherpolyurethane elastomers.

Claim 17

The process of claim 13 wherein said preformed, nonreactive polyurethane is an organosoluble polyesterpolyurethane based on diphenylmethane diisocyanate, adipic acid and an alkanediol having 2-4 carbon atoms or mixtures of such alkanediols.

Claim 18

The process of claim 12 wherein said preformed hard resin is a nonelastomeric, macromolecular film forming organic polymer, selected from the group consisting of vinylidene chloride/acrylonitrile and vinyl chloride/vinyl acetate copolymers.

Claim 19

The process of cLaim 12 wherein said polyol is selected from the group consisting of linear or branched aliphatic diols and triols, polymeric carboxylic esters, and addition polymers having available pendant reactive hydroxyl groups.

Claim 20

The process of claim 12 wherein said polyfunctional hydroxyl-reactive compound is a polyfunctional isocyanate.

Claim 21

The process of claim 18 wherein said polyfunctional isocyanate is selected from the group consisting of hexamethylene diisocyanate, diphenylmethane diisocyanate, diphenylmethane triisocyanate, toluene diisocyanate, polyethylene polyphenylisocyanate, the C36 diisocyanate from linoleic dimer acids, 4,4''-methylene-bis-(cyclohexylisocyanate), and the product of 2,4-toluene diisocyanate and trimethylol-propane reacted in a ratio of about 3 to 1 to about 5 to 2.

Claim 22

The process of claim 12 wherein said binder composition comprises about 15 to about 40% by weight of said preformed elastomer, about 30 to about 60% by weight of said preformed hard resin, about 2 to about 15% by weight of said polyol, and about 3.0 to about 25% by weight of said polyfunctional hydroxyl-reactive compound.

Claim 23

The process of claim 20 wherein said binder contains about 5 to about 40% by weight of said reaction product.

Claim 24

The process of claim 21 wherein said magnetic composition contains from about 65 to about 85% by weight of said ferromagnetic chromium dioxide particles.

Claim 25

The process of claim 22 wherein said preformed elastomer comprises an organosoluble polyesterpolyurethane resin based on diphenylmethane diisocyanate, adipic acid and an alkanediol having 2-4 carbon atoms or mixtures of such alkanediols; said preformed hard resin is selected from the group consisting of vinylidene chloride/acrylonitrile and vinyl chloride/vinyl acetate copolymers; said polyol is a polymeric carboxylic ester; said polyfunctional hydroxyl-reactive compound is the product of 2,4-toluene diisocyanate, and trimethylolpropane reacted in a ratio of about 3 to 1 to about 5 to 2; and said ferromagnetic particles are particles of acicular chromium dioxide.