# US 4,395,306 A · Method for preparing fibrous mats from a fibrous suspension

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- Number: US 4,395,306 A
- Document ID: US4395306A
- Status: Granted
- Kind: A
- Application number: 06/337,923
- Filed: 1982-01-08
- Granted: 1983-07-26
- Earliest claimed: 1980-01-31
- Assignees: The Dow Chemical Company
- Inventors: George R. Killat
- Web page: https://patentgrep.com/patent/US4395306A

## CPC

- D21H 13/40: vitreous, e.g. mineral wool, glass fibres
- C04B 26/04: obtained by reactions only involving carbon-to-carbon unsaturated bonds
- D21F 11/004: {by modification of the viscosity of the suspension}
- D21H 17/375: {Poly(meth)acrylamide}
- H01M 50/117: Inorganic material
- H01M 50/121: Organic material
- H01M 50/122: Composite material consisting of a mixture of organic and inorganic materials
- H01M 50/131: characterised by physical properties, e.g. gas permeability, size or heat resistance
- Y02E 60/10: Energy storage using batteries
- Y10T 442/2992: Coated or impregnated glass fiber fabric
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- D21F: PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Nonwoven mats or sheets having improved tensile strengths are prepared from a fibrous suspension of synthetic fibers thickened with a synthetic, addition polymer bearing pendant carboxamide groups and a cross-linking agent for the polymeric thickener. For example, a fibrous suspension comprising glass fibers, a polymer of acrylamide and a water-soluble hypohalite can be employed to prepare strong, glass fiber mats useful as effective reinforcement for roofing shingles.

## Claims

### Claim 1

An improved method for preparing a fibrous mat or sheet by depositing a layer of a thickened fibrous suspension of synthetic fibers and an aqueous suspending medium thickened by a carboxamide synthetic addition polymer on a support, removing substantially all of said suspending medium to leave a fibrous mat with a residuum of a minor amount of said carboxamide polymer on the fibers, the improvement wherein said carboxamide polymer is reacted with a hypohalite to form a reaction product in said suspending medium, which as said residuum will cross-link to provide a fibrous mat of improved strength.

### Claim 2 (depends on 1)

The improved method of claim 1 wherein the synthetic addition polymer is a water-soluble polymer of an ethylenically unsaturated carboxamide or an N-substituted ethylenically unsaturated carboxamide.

### Claim 3 (depends on 1)

The improved method of claim 1 wherein the synthetic, addition polymer is derived from an ethylenically unsaturated carboxamide and the cross-linking agent is an ammonium or alkali metal hypohalite.

### Claim 4 (depends on 1)

The improved method of claim 1 wherein the cross-linking agent is employed in an amount of from about 0.01 to about 0.5 equivalent per equivalent of the polymeric thickener.

### Claim 5 (depends on 2)

The improved method of claim 2 wherein the N-substituted ethylenically unsaturated carboxamide is an N-substituted (N', N'-dialkylaminoalkyl)acrylamide.

### Claim 6 (depends on 5)

The improved method of claim 5 wherein at least about 50 mole percent of the polymerized monomer units comprising the polymeric thickener bear pendant groups which are N-substituted carboxamides of the formula: ##STR3## wherein R is individually hydrogen, alkyl, aminoalkyl or dialkylaminomethyl provided both R's are not hydrogen.

### Claim 7 (depends on 6)

The improved method of claim 6 wherein each R is a dialkylaminomethyl group.

### Claim 8 (depends on 7)

The improved method of claim 7 wherein each R is dimethylaminomethyl.

### Claim 9 (depends on 8)

The improved method of claim 8 wherein the cross-linking agent is an ammonium or alkali metal hypochlorite and is employed in an amount of from about 0.01 to about 0.5 equivalent per equivalent of the polymeric thickener.

### Claim 10 (depends on 9)

The method of claim 9 wherein the cross-linking agent is sodium hypochlorite.

### Claim 11 (depends on 1)

The improved method of claim 1 wherein the fibrous mat or sheet is prepared from a thickened, fibrous suspension comprising synthetic fibers and an aqueous suspending medium thickened by a carboxamide polymer which suspension further comprises a cross-linking agent for the polymeric thickener, the cross-linking agent being in an amount which does not cause precipitation of the polymer.

### Claim 12 (depends on 1)

The improved method of claim 1 wherein the fibers are contacted with the cross-linking agent for the polymeric thickener by spraying an aqueous solution of the cross-linking agent on the fibrous mat or sheet prepared from the thickened, fibrous suspension.

### Claim 13 (depends on 12)

The improved method of claim 12 which further comprises applying a binder to the fibrous mat or sheet.

### Claim 14 (depends on 1)

The improved method of claim 1 wherein said synthetic fibers are glass fibers.

### Claim 15

A thickened, fibrous suspension comprising an aqueous suspension of synthetic fibers thickened with a synthetic carboxamide polymer and an amount of a water-soluble hypohalite cross-linking agent for the polymeric thickener such that a fibrous mat or sheet prepared from the thickened, fibrous suspension exhibit increased tensile strength.

### Claim 16 (depends on 15)

The suspension of claim 15 wherein said fibers are glass fibers.