Wash-off film containing synthetic amphoteric polymers

Claim 2

A wash-off film for tanning development comprising at least one unhardened gelatin-containing layer of which at least one gelatin-containing layer is an unhardened silver halide emulsion with a gelatin binder, the improvement wherein 5 to 60% by weight of the gelatin in at least one of the gelatin-containing layers is replaced with a water soluble synthetic acrylic amphoteric addition polymer consisting essentially of at least one of each of three constituents: (a) carboxylic acid selected from the group consisting of acrylic acid and methacrylic acid, (b) acrylic alkyl primary amine, and (c) acrylic secondary and/or tertiary amine, constituents (a), (b) and (c) being present in 10 to 60 mole percent, 1 to 20 mole percent, and 10 to 60 mole percent, respectively, based on the total moles of the amphoteric polymer whereby a sharper wash-off image is obtained by incorporation of the amphoteric polymer.

Claim 3

A wash-off film according to claim 1 wherein 10 to 20% by weight of gelatin is replaced by synthetic acrylic amphoteric polymer.

Claim 4

A wash-off film according to claim 1 wherein a tanning developer is present in at least one of the gelatin-containing layers.

Claim 5

A wash-off film according to claim 1 wherein stabilized carbon black is present in at least one of the gelatin-containing layers.

Claim 6

A wash-off film according to claim 1 wherein the acrylic amphoteric polymer has an isoelectric point of 4 to 8.

Claim 7

A wash-off film according to claim 1 wherein the acrylic amphoteric polymer contains aminopropylacrylate.

Claim 8

A wash-off film according to claim 1 wherein component (b) is an alkyl primary amine taken from the group consisting of 2-aminopropyl acrylate, 2-aminopropyl methacrylate, aminoethyl acrylate and aminoethyl methacrylate.

Claim 9

A wash-off film according to claim 1 wherein component (c) is a secondary and/or tertiary amine taken from the group consisting of dimethylaminoethyl methacrylate, morpholinoethyl methacrylate, diethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, and piperidinoethyl methacrylate.

Claim 10

A process for preparing a wash-off film for tanning development which comprises (a) preparing by emulsion polymerization in a reaction medium a prepolymer by reacting methyl acrylate and one or more acrylic monomers having secondary and/or tertiary amine functionality: (b) hydrolyzing the methyl acrylate moiety of the prepolymer to acrylic acid groups; (c) neutralizing the reaction medium; (d) reacting acrylic acid groups of the prepolymer with ethyleneimine or propyleneimine to form an amphoteric polymer with pendant alkyl primary amine groups; (e) separating the acrylic amphoteric polymer from the reaction medium: (f) incorporating the acrylic amphoteric polymer into an unhardened gelatino-silver halide wash-off emulsion, the acrylic amphoteric polymer replacing 5 to 60% of the gelatin binder of the unhardened gelatino-silver halide emulsion.

Claim 11

A process for preparing a wash-off film for tanning development which comprises (a) preparing by emulsion polymerization in a reaction medium a prepolymer by reacting methyl acrylate and one or more acrylic monomers having secondary and/or tertiary amine functionality: (b) hydrolyzing the methyl acrylate moiety of the prepolymer to acrylic acid groups; (c) neutralizing the reaction medium; (d) reacting acrylic acid groups of the prepolymer with ethyleneimine or propyleneimine to form an amphoteric polymer with pendant alkyl primary amine groups; (e) separating the acrylic amphoteric polymer from the reaction medium: (f) incorporating the acrylic amphoteric polymer into an unhardened gelatino-silver halide wash-off emulsion, the acrylic amphoteric polymer replacing 5 to 60% of the gelatin binder of the unhardened gelatino-silver halide emulsion.

Claim 12

A process according to claim 9 wherein in step (a) the prepolymer is prepared with at least one of the following monomers: dimethylaminoethyl-methacryalte, diethylaminoethyl methacrylate, morpholino- ethyl methacrylate, piperidinoethyl methacrylate and t-butylaminoethyl methacrylate.

Claim 13

A process according to claim 10 wherein the hydrolyzing step (b) is carried out with potassium hydroxide.

Claim 14

A process according to claim 11 wherein the neutralizing step (c) is carried out with nitric acid.

Claim 15

A process according to claim 12 wherein the reacting step (d) is carried out at a temperature of at least 60° C.

Claim 16

A process according to claim 13 wherein acetone or ethanol is used in the separating step (e).

Claim 17

A wash-off film prepared according to the process of claim 9 wherein the gelatino-silver halide emulsion in addition to the acrylic amphoteric polymer contains stabilized carbon black and a tanning developer.

Claim 18

A process according to claim 9 wherein the secondary or tertiary amine monomers are prepared by transesterification of methyl methacrylate and a secondary or tertiary amine compound.

Claim 19

A process according to claim 9 wherein the tertiary amine monomers are prepared by reaction between isocyanatoethyl methacrylate and a tertiary amine compound with an alcoholic functionality.

Claim 20

A process according to claim 9 wherein the secondary and/or tertiary amine monomers are taken from the group consisting of dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, morpholinoethyl methacrylate, t-butylaminoethyl methacrylate, piperidinoethyl methacrylate, 2-((2-dimethylaminoethyl) carbamamido)ethyl methacrylate, 2-((diethylaminoethyl) carbamamido)ethyl methacrylate. 2-((2-morpholinoethyl) carbamamido)ethyl methacrylate, and 2-((2-piperidinoethyl)carbamamido)-ethyl methacrylate.

Claim 21

A process for preparing a wash-off film for tanning development which comprises (a) preparing a solution of at least one acrylic monomer having a primary amine functionality and at least one acrylic monomer having a secondary and/or tertiary amine functionality; (b) adding acid to protonate the amine monomers; (c) adding acrylic and/or methacrylic acid monomer; (d) heating the solution of monomers in the presence of a polymerization initiator to react the monomers and cooling to ambient temperature whereby an acrylic amphoteric polymer is formed; (e) neutralizing excess acid from the acrylic amphoteric polymer; (f) separating the acrylic amphoteric polymer from the solution; and (g) incorporating the acrylic amphoteric polymer into an unhardened gelatino-silver halide wash-off emulsion, the acrylic amphoteric polymer replacing 5 to 60% of the gelatin binder of the unhardened gelatino-silver halide emulsion.

Claim 22

A process for preparing a wash-off film for tanning development which comprises (a) preparing a solution of at least one acrylic monomer having a primary amine functionality and at least one acrylic monomer having a secondary and/or tertiary amine functionality; (b) adding acid to protonate the amine monomers; (c) adding acrylic and/or methacrylic acid monomer; (d) heating the solution of monomers in the presence of a polymerization initiator to react the monomers and cooling to ambient temperature whereby an acrylic amphoteric polymer is formed; (e) neutralizing excess acid from the acrylic amphoteric polymer; (f) separating the acrylic amphoteric polymer from the solution; and (g) incorporating the acrylic amphoteric polymer into an unhardened gelatino-silver halide wash-off emulsion, the acrylic amphoteric polymer replacing 5 to 60% of the gelatin binder of the unhardened gelatino-silver halide emulsion.

Claim 23

A process according to claim 19 wherein in step (a) the acrylic monomer present has solely secondary and/or tertiary amine functionality and after step (e) the acid group of the amphoteric polymers are reacted with ethyleneimine or propyleneimine to form an acrylic amphoteric polymer with pendant alkyl primary amine groups.

Claim 24

A process according to claim 19 wherein the acrylic monomer having amine functionality is placed in a water-alcohol solution.

Claim 25

A process according to claim 19 wherein the polymerization initiator is potassium persulfate.

Claim 26

A process according to claim 19 wherein the acid used in step (b) is nitric acid.

Claim 27

A process according to claim 23 wherein potassium hydroxide is used to neutralize excess acid in step (e).

Claim 28

A process according to claim 19 wherein the acrylic monomer having secondary and/or tertiary amine functionality is taken from the group consisting of dimethylaminoethyl methacrylate, morpholinoethyl methacrylate, diethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, piperidinoethyl methacrylate, and mixtures thereof.

Claim 29

A process according to claim 25 wherein the acrylic monomer having primary amine functionality is taken from the group consisting of aminoethyl methacrylate, aminoethyl acrylate, 2-aminopropylacrylate and 2-aminopropylmethacrylate.