Binder for high wet-strength substrates
First Claim
1. A fibrous substrate comprising chemically bonded fibers wherein said fibers are bonded by a polymeric binder wherein said binder is present in an amount which is sufficient to bind the fibers together to form a self-sustaining web, and wherein said binder is characterized as having an average cross-machine direction (CMD) wet tensile strength of greater than 4500 grams per inch (g/in) when measured at a 20 percent add-on using Whatman #4 CHR Chromatography paper which is drum dried for 90 seconds at 210 to 215°
- F. and cured for 2 minutes at 300 to 325°
F.
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Accused Products
Abstract
The present invention is directed to a fibrous substrate made of chemically bonded fibers, where the fibers are bound with a polymeric binder in an amount which is sufficient to bind the fibers together to form a self-sustaining web, and where the binder is characterized as having a wet tensile strength of greater than 4500 grams per inch (g/in) when measured at a 20 percent add-on on Whatman #4 CHR chromatography paper which is drum dried for 90 seconds at 210 to 215° F. and cured for 2 minutes at 300 to 325° F. Preferably the level of free formaldehyde in the fibrous substrate is less than 15 ppm. The emulsion binders of the invention may be used to bind fibers together in a substrate; may be used to bind pigment, colors or other substances to a substrate; may be used as a backing material; or may be used to finish or surface-treat a substrate. Because of the high level of crosslinking, substrates bound, or treated with the emulsion polymer have excellent wet strength and good durability/weatherability and water/solvent resistance.
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Citations
20 Claims
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1. A fibrous substrate comprising chemically bonded fibers wherein said fibers are bonded by a polymeric binder wherein said binder is present in an amount which is sufficient to bind the fibers together to form a self-sustaining web, and wherein said binder is characterized as having an average cross-machine direction (CMD) wet tensile strength of greater than 4500 grams per inch (g/in) when measured at a 20 percent add-on using Whatman #4 CHR Chromatography paper which is drum dried for 90 seconds at 210 to 215°
- F. and cured for 2 minutes at 300 to 325°
F. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- F. and cured for 2 minutes at 300 to 325°
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9. A bonded substrate comprising
a) a substrate comprising fibers; - and
b) a polymeric binder comprising at least 6 percent by weight of cross-linking monomer units, wherein said bonded substrate is characterized as having less than 15 ppm of free formaldehyde, and wherein said binder is present in an amount which is sufficient to bind the fibers together to form a self-sustaining web. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A non-woven product comprising a non-woven web of fibers bonded together with an emulsion polymer binder comprising
a) at least 50 percent by weight percent of vinyl ester units; -
b) 0 to 40 percent by weight of ethylene units;
c) 5 to 20 percent by weight of crosslinking monomer units;
d) 0.1 to 5 percent by weight of acrylamide, methacrylamide, or a mixture thereof. e) 0 to 40 percent by weight of other co-monomers wherein said non-woven product has a free formaldehyde content after drying of less than 15 ppm. - View Dependent Claims (18, 19, 20)
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Specification