Fluid containers having both relatively strong and relatively weak seals

Claim 2

A fluid container in accordance with claim 2 wherein said first polymer is selected from the group consisting of cellulose nitrate and alcohol soluble cellulose acetate butyrate, and wherein said second polymer is selected from the group consisting of styrene-methyl methacrylate copolymer, toluene soluble cellulose acetate butyrate, and polyvinyl butyral.

Claim 3

A fluid container in accordance with claim 3 wherein said first and second polymers are present in a ratio between 4 to 1 and 1 to 4 by weight.

Claim 4

A fluid container in accordance with claim 4 wherein said mixture consists essentially of styrene-methyl methacrylate copolymer and alcohol soluble cellulose acetate butyrate.

Claim 5

A fluid container in accordance with claim 4 wherein said mixture consists essentially of toluene soluble cellulose acetate butyrate and alcohol soluble cellulose acetate butyrate.

Claim 6

A fluid container in accordance with claim 4 wherein said mixture consists essentially of polyvinyl butyral and alcohol soluble cellulose acetate butyrate.

Claim 7

A fluid container in accordance with claim 4 wherein said mixture consists essentially of polyvinyl butyral and cellulose nitrate.

Claim 8

A fluid container in accordance with claim 1 wherein said walls at least over the marginally sealed areas thereof have a heat sealable coating comprising such an intimate mixture of a thermoplastic polymer selected from the group consisting of alcohol soluble cellulose acetate butyrate, toluene soluble cellulose acetate butyrate, and a polyhydroxy ether resulting from copolymerization of bisphenol A with epichlorohydrin; and a plasticizer selected from the group consisting of triphenyl phosphate and sulfonamide-formaldehyde resin; said misture being characterized by the ability to form a relatively strong seal when subjected to one set of conditions of temperature, pressure and time, and to form a relatively weaker seal when subjected to a different set of conditions.

Claim 9

A fluid container in accordance with claim 9 wherein said thermoplastic polymer is alcohol soluble cellulose acetate butyrate, and wherein said plasticizer is sulfonamide-formaldehyde resin.

Claim 10

A fluid container in accordance with claim 9 wherein said thermoplastic polymer is alcohol soluble cellulose acetate butyrate, and wherein said plasticizer is triphenyl phosphate.

Claim 11

A fluid container in accordance with claim 9 wherein said thermoplastic polymer is a polyhydroxy ether resulting from copolymerization of bisphenol A with epichlorohydrin, and wherein said plasticizer is sulfonamide-formaldehyde resin.

Claim 12

A fluid container in accordance with claim 9 wherein said thermoplastic polymer is a polyhydroxy ether resulting from copolymerization of bisphenol A with epichlorohydrin, and wherein said plasticizer is triphenyl phosphate.

Claim 13

A fluid container in accordance with claim 9 wherein said thermoplastic polymer is toluene soluble cellulose acetate butyrate, and wherein said plasticizer is triphenyl phosphate.

Claim 14

A method of forming a fluid container in accordance with claim 1, comprising providing a pair of opposed walls having the entire internal areas thereof provided with an underlayer of heat sealable resin and over at least marginal areas thereof on top of said underlayer an overcoating of a chemical composition comprising at least one thermoplastic polymer, said composition being selected from the group consisting of (a) a mixture of two polymers, the first one of said polymers being selected from the group consisting of cellulose nitrate and alcohol soluble cellulose acetate butyrate, the second one of said polymers being selected from the group consisting of styrene-methyl methacrylate copolymer, toluene soluble cellulose acetate butyrate, and polyvinyl butyrate, said first one of said polymers being characterized by inherent relatively weak heat sealability, said second one of said polymers being characterized by inherent relatively stronger heat sealability; and (b) a mixture of a polymer selected from the group consisting of alcohol soluble cellulose acetate butyrate, a polyhydroxy ether resulting from copolymerization of bisphenol A with epichlorohydrin, and toluene soluble cellulose acetate butyrate, with a plasticizer selected from the group consisting of triphenyl phosphate and sulfonamide-formaldehyde resin; placing said opposed walls together over said marginal areas; subjecting a first part of said marginal areas to one set of conditions of temperature, pressure, and time to form a relatively strong seal; and subjecting another part of said marginal areas to a different set of conditions of temperature, pressure, and time effective to form a relatively weaker seal, whereby liquid is releasable through said weaker seal upon application of pressure to said container.

Claim 15

A method in accordance with claim 15 wherein said composition comprises said first polymer selected from the group consisting of cellulose nitrate and alcohol soluble cellulose acetate butyrate, and said second polymer selected from the group consisting of styrene-methyl methacrylate copolymer, toluene soluble cellulose acetate butyrate, and polyvinyl butyral.

Claim 16

A method in accordance with claim 15 wherein said composition comprises a polymer selected from the group consisting of alcohol soluble cellulose acetate butyrate, toluene soluble cellulose acetate Butyrate, and a polyhydroxy ether resulting from copolymerization of bisphenol A with epichlorohydrin; and a plasticizer selected from the group consisting of triphenyl phosphate and sulfonamide-formaldehyde resin.

Claim 17

A method in accordance with claim 15, also comprising providing said coating by dissolving the selected composition in a solvent, coating the resulting solution on said areas, and permitting said solvent to evaporate.

Claim 18

A method in accordance with claim 15, wherein said first part of said area is sealed at a temperature between 200* and 400* F., and said other part of said area is sealed at a lower temperature between 150* and 350* F.

Claim 19

A fluid container in accordance with claim 1 wherein said selected part of said area having a relatively strong seal comprises two opposite sides of said fluid container, and wherein said other part of said area comprises the other two opposite sides, said other two opposite sides being sealed with seals of essentially the same relatively weaker strength.

Claim 20

A fluid container in accordance with claim 1 wherein said walls comprise a plurality of layers, one of said layers being lead foil, another of said layers being kraft paper adhering to the outside of said lead foil, and another of said layers being a polymeric resin adhering to the inside of said lead foil between said lead foil and said coating.

Claim 21

A fluid container in accordance with claim 5 wherein said walls comprise a plurality of layers, one of said layers being lead foil, another of said layers being kraft paper adhering to the outside of said lead foil, and another of said layers being a polymeric resin adhering to the inside of said lead foil between said lead foil and said coating.

Claim 22

A fluid container in accordance with claim 9 wherein said walls comprise a plurality of layers, one of said layers being lead foil, another of said layers being kraft paper adhering to the outside of said lead foil, and another of said layers being a polymeric resin adhering to the inside of said lead foil between said lead foil and said coating.

Claim 23

A method in accordance with claim 19 wherein said composition consists essentially of alcohol soluble cellulose acetate butyrate and styrene-methyl methacrylate copolymer in a ratio between 4 to 1 and 1 to 4 by weight.

Claim 24

A container in accordance with claim 22 filled with an alkaline photographic processing solution.

Claim 25

A fluid container for photographic processing liquid having a pair of opposed walls marginally sealed together over a substantial sealing area to provide a liquid retaining cavity, at least one of said walls being flexible and deformable, said opposed walls over the entire internal areas thereof each having a processing liquid-resistant thermoplastic polymeric vinyl resin layer; said opposed walls over at least a marginal area thereof each having a coating over said vinyl resin layer of a mixture of alcohol soluble cellulose acetate butyrate and styrene-methyl methacrylate copolymer in a ratio between 4 to 1 and 1 to 4 by weight; part of said sealing area comprising a relatively strong seal comprising vinyl resin of said layers fused together, the remainder of said sealing area comprising a relatively weaker seal comprising only said coatings fused together.