Paper making and fiber liberation – Processes and products – Non-fiber additive
Reexamination Certificate
2000-09-20
2002-02-12
Woodward, Ana (Department: 1711)
Paper making and fiber liberation
Processes and products
Non-fiber additive
C162S164600, C162S175000, C162S177000, C162S178000, C162S180000
Reexamination Certificate
active
06346170
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to dry strength additives for paper and more particularly it relates to polyamidoamine/epichlorohydrin resins bearing polyol sidechains.
2. Description of the Prior Art
Strength is a very important property of paper products. At constant basis weight, the use of dry strength additives increases strength. Dry strength agents enable the papermaker to use less pulp, less expensive pulp and/or more filler while making sufficiently strong, stiff and opaque paper products. Benefits to the users of paper products include stronger packaging and lower shipping or postage costs. Conventional dry strength agents include starch, urea/formaldehyde resins, melamine/formaldehyde resins, acrylamide copolymers and polyamidoamine/epichlorohydrin resins.
U.S. Pat. No. 3,962,159 (Ray-Chaudhuri, et al.) discloses copolymerization of water dispersible starches, polyamidoamines and epichlorohydrin. The weight ratio of starch to polyamidoamine is between 1:9 and 9:1. While Ray-Chaudhuri uses the term “graft copolymer” in fact he is making block copolymers of the polyamidoamines and starch using epichlorohydrin as a condensing agent. All U.S. Pat. No. 3,962,159 preparations form carbon-oxygen bonds between the starch and the polyamidoamine except for the one in Example 19 where a quaternary ammonium bond is formed.
U.S. Pat. No. 3,314,897 (Gaertner) discloses treating polysaccharide substrates (starch, textiles, such as cotton, linen, rayon, and cellulose paper products) with a minor amount of a prepolymer composed of aliphatic amine/epichlorohydrin adduct reacted with an amine having at least 2 amino hydrogens. In other words Gaertner uses a minor amount of his prepolymer to modify the polysaccharide substrates instead of modifying a polyamidoamine/epichlorohydrin resin by including polyol sidechains and obtaining a water soluble product.
U.S. Pat. No. 3,320,066 (Garth) discloses the separate addition of polyamide-epichlorohydrin resin, dialdehyde carbohydrate and optionally carboxymethyl cellulose and/or cationic starch to paper pulp, i.e., to the dilute slurry of paper pulp obtained after the beating operation.
South African Patent 695018 discloses starch/polymeric polyamine compositions wherein the polyamine is formed by a reaction of an alkylene dihalide, e.g. ethylene dichloride, and an amine, e.g., diethylenetriamine. There is no disclosure of making a polyaminoamide or a polyaminoamide/epichlorohydrin resin.
French Patent 1,488,141 (which corresponds to Canadian patent 797,130) discloses improving the strength of cellulosic material by (a) treating an aqueous suspension of cellulose fibers with a cationic wet strength resin (such as cationic urea-formaldehyde resin, and cationic polyamides, obtained from the reaction of polyalkylenepolyamine and dicarboxylic acid which are crosslinked with epichlorohydrin) (b) adjusting the pH of the suspension to 4.0-5.5, (c) treating the suspension with a dialdehyde polysaccharide, (d) adjusting the pH of the suspension to 4.0-5.5 and (e) forming a web from the treated cellulose fibers.
U.S. Pat. No. 4,097,427 (Aitken) discloses the interaction of polyalkylenepolyamine/epichlorohydrin resins with starch for improved wet strength. It does not disclose polyamidoamine/epichlorohydrin resins.
U.S. Pat. No. 3,763,060 (Hamerstrand et al.) discloses the interaction of sodium starch xanthate with polyamide polyamine-epichlorohydrin (PAE) resin wherein the bond between the starch xanthate and the PAE resin is a carbon-sulphur bond.
U.S. Pat. No. 4,940,514 ( Stange, et al.) discloses the interaction of vinyl polymers with enzymatically digested starch. There is no disclosure of polyamidoamine/epichlorohydrin resins.
U.S. Pat. No. 4,818,341 (Degen, et al.) discloses the interaction of vinyl polymers with enzymatically digested starch. There is no disclosure of polyamidoamine/epichlorohydrin resins.
U.S. Pat. No. 5,334,287 (Hartmann, et al.) discloses the use of N-vinylcarboxamide free radical graft copolymers of mono-, oligo- or poly-saccharides. It does not disclose polyamidoamine/epichlorohydrin resins.
SUMMARY OF THE INVENTION
According to the present invention there are provided compositions for improving the dry strength of paper comprising water-soluble, azetidinium ion-containing polyamidoamine/epichlorohydrin resins bearing polyol sidechains wherein the weight fraction of the polyol in the resin is less than 50% by weight and the polyol sidechain is attached to the polyamidoamine/epichlorohydrin resin by a carbon-nitrogen bond.
According to the present invention there are provided processes for the preparation of the water-soluble polyamidoamine/epichlorohydrin resins bearing polyol sidechains.
According to the present invention there is provided paper having improved dry strength characteristics containing water soluble polyamidoamine/epichlorohydrin resins bearing polyol sidechains.
According to the present invention there is further provided the process to enhance the dry strength of paper by adding to the aqueous pulp the water-soluble polyamidoamine/epichlorohydrin resins bearing polyol sidechains.
DETAILED DESCRIPTION OF THE INVENTION
It has been discovered that water-soluble, azetidinium ion-containing polyamidoamine/epichlorohydrin resins bearing polyol sidechains, wherein the weight fraction of the polyol in the resin is less than 50% by weight and the polyol sidechain is attached to the polyamidoamine/epichlorohydrin resin by amide, secondary amine or tertiary amine carbon-nitrogen bonds, will improve the dry strength of paper and as such will have an economic benefit for both the papermaker and the paper user.
The polyamidoamines are prepared by the method described in U.S. Pat. No. 2,926,116 and EPA 488,767. Polyamidoamine/epichlorohydrin resins having aminochlorohydrin, azetidinium and/or epoxide functionality may be prepared as described in U.S. Pat. Nos. 2,926,116; 5,171,795; EPA 488,767; GB 865,727; U.S. Pat. Nos. 4,605,709; and 4,537,657. The disclosure of these patents is incorporated herein by reference.
Polyol sidechains are defined as organic residues containing two or more hydroxyl groups, wherein at least half of the carbon atoms in the polyol sidechain bear hydroxyl groups. In order to be useful as starting materials for the compositions of the present invention, the precursor molecule of a polyol sidechain must also have one, and only one, functional group selected from the group consisting of carboxylic acid, lactone, amine and aldehyde. Carbohydrates, including monosaccharides, disaccharides, oligosaccharides and polysaccharides, glycerol, glyceraldehyde, 3-amino-1,2-propanediol, 3-alkylamino-1,2-propanediol,3-hydroxyethylamino-1,2-propanediol, threose, erythrose, xylose, arabinose, ribose, fructose, glucose, galactose, mannose, sucrose, maltbiose, maltotriose, lactose, cellobiose, hemicellulose, cellulose, starch, dextrin, pyrodextrin, alginate, glycogen, inulin, furcellaran, agar, carrageenan, microbial gum, locust bean gum, fucoidan, guar, laminaran, gum arabic, ghatti gum, karaya gum, tragacanth gum, okra gum, tamarind gum, xanthan, scleroglucan, psyllium gum, pectin, dextran, methylcellulose, ethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose and chitin are polyol sidechain precursors or they may be converted to polyol sidechain precursors. If not already present, a carboxylic acid, lactone, amine or aldehyde functional group can be provided to the structure of the starting material using conventional synthetic methods. For example, chitin may be depolymerized and deacetylated to form glucosamine, or alginate may be completely decarboxylated to give a terminal monoaldehyde.
Preferred polyol residues are threityl, erythrityl, xylityl, arabinityl, ribityl, fructityl, glucityl, galactityl, mannityl, maltobiotyl, maltotriotyl, lactobiotyl, cellobiotyl and pryrodextrinityl. For example, the term “glucityl polyol residue” refers to the 6-carbon polyol sidechain attached by means of the precursors 1-amino-1-deoxysorbitol, 1-methylamino-1-deox
Greenblum & Bernstein P.L.C.
Hercules Incorporated
Woodward Ana
LandOfFree
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