Non-fogging material

Claim 2

A material in accordance with claim 1 in which the cross-linking compound contains functional groups capable of reacting with the polyalkylene imine selected from a nonaromatic ethylenic unsaturated group, an epoxy group, a halo group, a carboxylic acid or anhydride group, an aldehyde group, a ketonic group, an isocyanato or isothiocyanato group or a phenolic hydroxy group.

Claim 3

A material in accordance with claim 2 in which the polyalkylene imine is polyethylene imine.

Claim 4

cooling the reaction solution of step (2) if necessary to prevent an exothermic runaway reaction;

Claim 5

after thermally stabilizing the reaction of step (2), adding at least one cross-linking compound to the solution which is capable of reacting with and cross-linking the polyalkylene imine polymer, said cross-linking compound being present in quantities sufficient to yield a water insoluble coating upon complete reaction;

Claim 6

A material in accordance with claim 1 in which the mono-functional reactive compound containing a polar functional group contains such a group selected from a cyano group, an amido group, an acetyl group and an aryl group.

Claim 7

A material in accordance with claim 4 in which the polyalkylene imine is polyethylene imine.

Claim 8

heating the solution containing the cross-linking compound to partially react it with the polyalkylene imine without cross-linking the imine polymer to a degree that the polymer will gel or come out of solution;

Claim 9

cooling the partially cross-linked polyalkylene imine solution to stabilize it;

Claim 10

A material in accordance with claim 1 in which there are at least three reactive compounds attached to the polyalkylene imine, two of said reactive compounds functioning as cross-linking compounds and another being a monofunctional reaCtive compound containing a polar functional group to promote adhesion to the substrate.

Claim 11

A material in accordance with claim 6 in which the cross-linking compounds are present in amounts of about 0.3 to 2.5 moles per equivalent weight of the alkylene imine repeating unit and the compound containing the polar functional group is present in an amount up to about 0.80 mole per equivalent weight of the alkylene imine repeating unit.

Claim 12

applying the partially cross-linked polyalkylene imine solution to at least one surface of the substrate; and

Claim 13

heating the coated substrate to cause the solvent to be driven off and the cross-linking reaction to be completed whereby substantially all of the nitrogen atoms of the polyalkylene imine are attached to a plurality of reactive compounds so as to provide a non-fogging, water-insoluble, hydrophilic coated substrate.

Claim 14

A material in accordance with claim 7 in which the polyalkylene imine is polyethylene imine, two of the cross-linking compounds are epichlorohydrin and N,N''-methylene bisacrylamide and the mono-functional compound containing a polar group is acrylonitrile.

Claim 15

A material in accordance with claim 8 in which the substrate is polycarbonate.

Claim 16

A material in accordance with claim 7 in which two of the cross-linking compounds are epichlorohydrin and glycidyl methacrylate and the mono-functional compound containing a polar group contains an acrylamide group.

Claim 17

A material in accordance with claim 10 in which the polyalkylene imine is polyethylene imine and the compound containing an acrylamide group is isopropyl acrylamide.

Claim 18

A material in accordance with claim 10 in which the substrate is polycarbonate.

Claim 19

A material in accordance with claim 7 in which the substrate is polycarbonate.

Claim 20

A material in accordance with claim 6 in which the substrate is polycarbonate.

Claim 22

The method of claim 15 in which the cross-linking compound is added to the polyalkylene imine solution in step (4) in an amount of about 0.3 to 2.5 moles per equivalent weight of the alkylene imine repeating unit.

Claim 23

The method of claim 15 in which the polyalkylene imine is polyethylene imine.

Claim 24

The method of claim 15 in which the mono-functional reactive compound containing a polar functional group is selected from the group consisting of acrylonitrile, an acrylamide, a methacrylamide, a methacrylate and an acrylate.

Claim 25

The method of claim 15 in which the cross-linking compound contains functional groups capable of reacting with the polyalkylene imine selected from a nonaromatic ethylenic unsaturated group, an epoxy group, a halo group, a carboxylic acid or anhydride group, an aldehyde group, a ketonic group, an isocyanato or isothiocyanato group and a phenolic hydroxy group.

Claim 26

The method of claim 15 in which the substrate is a polymer whose surface is oxidized or sulfonated prior to applying the coating in step (7).

Claim 27

The method of claim 15 in which the substrate is polycarbonate whose surface is treated with a dilute solution of chromic acid in concentrated sulfuric acid prior to applying the coating in step (7).

Claim 28

The method of claim 15 in which the cross-linking compound is added and reacted with the polyalkylene imine in at least two parts by: 4A. adding a first cross-linking compound to the polyalkylene imine solution to react with the polyalkylene imine without causing the polyalkylene imine to cross-link to a degree that the imine polymer will gel or come out of solution; 4B. adding a second cross-linking compound to the solution containing the polyalkylene imine and the first cross-linking compound, said second cross-inking compound being capable of reacting with both the amine hydrogen and the nitrogen of the polyalkylene imine; and 4C. reacting the first and second cross-linking compounds with the polyalkylene imine to increase the molecular weight without cross-linking the imine polymer to a degree that the imine polymer will gel or come out of solution.

Claim 29

The method of claim 22 in which the first cross-linking compound is glycidyl methacrylate and the second cross-linking compound is epichlorohydrin

Claim 30

The method of claim 23 in which the polyalkylene imine is polyethylene imine with a molecular weight in the range of about 400 to about 1,000.