Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-07-26
2002-04-30
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S047000, C524S062000, C524S112000, C524S198000, C524S364000, C524S423000, C524S437000, C524S501000, C106S238000
Reexamination Certificate
active
06380299
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to novel aqueous dispersions for paper sizing. In particular, the invention relates to aqueous dispersions which essentially comprise reinforced or nonreinforced, esterified or nonesterified colophonium, a synthetic surfactant, a polymer that is water-soluble or can be dispersed in water, optionally an extender, optionally a synthetic sizing agent, optionally an aluminum-containing fixative, and water. The individual components of the novel dispersions will be described in further detail hereinafter. The novel dispersions of this invention are intended for use for finishing paper or cardboard.
In U.S. Pat. No. 3,966,654, aqueous dispersions are described that substantially comprise reinforced colophonium, a water-soluble cationic resin-based dispersant, and water. The dispersant is selected from among the following products: water-soluble aminopolyamide epichlorohydrin resins, water-soluble alkylenepolyamine epichlorohydrin resins, and water-soluble poly(diallylamine) epichlorohydrin resins. The reinforced colophonium is the addition reaction product of colophonium and an acid compound that contains the group
Methods for preparing these dispersions are also disclosed.
In European Patent 0 056 876, aqueous dispersions are described that substantially comprise reinforced colophonium, a cationic starch-based dispersant that is water-soluble or can be dispersed in water, an anionic surfactant, and water. Two methods for preparing these dispersions are described: First, the dispersal can be done from a solution of the resin in an organic solvent (methylene chloride is used in the examples) by evaporation of the solvent in a vacuum, or secondly, by direct mixing of the hot, molten resin with an emulsifier and starch solution in a dispergator at high temperatures and with high shear forces.
In European Patent 0 074 544, aqueous dispersions are described that substantially comprise reinforced colophonium, water-soluble cationic nitrogen-containing dispersants, a synthetic sizing agent that reacts with cellulose, and water.
In European Patent 0 200 755, an aqueous dispersion in a non-saponified, preferably reinforced resin acid is described. This dispersion contains cationic organic compounds, preferably a cationic starch, cationic polyacrylamide, cationic polyamine, cationic polyamidamine, or cationic polyethylenimine. In the aqueous phase, the dispersion contains an aluminum salt, which is a polyaluminum chloride or a polyaluminum sulfate.
In European Patent 0 275 851, a mixture of a resin dispersion with synthetic sizing agent and a polyaluminum compound is claimed. This aqueous dispersion is characterized in that the dispersed phase comprises particles which contain a mixture of resin material and a synthetic sizing agent, and that the dispersion contains a polyaluminum compound in which ion contains at least four aluminum atoms. The mixture of resin material and synthetic sizing agent contains from 10 to 96% of the resin material. The synthetic sizing agent is carbamoyl chloride or ketene dimer. The polyaluminum compound is polyaluminum chloride or polyaluminum sulfate.
European Patent 0 200 002 claims colophonium-based paper sizing agents that are characterized in that the cationization of a stable anionic glue is done with polyaluminum chloride and optionally with the addition of a cationic polymer. International Patent Disclosure WO 90/08852 also describes a method for producing a cationic glue by adding polyaluminum chloride to a stable dispersion of maleic acid anhydride-reinforced colophonium. Both methods have in common the fact that they are based on a stable aqueous dispersion, which must accordingly contain a relatively high proportion of emulsifier, which can adversely affect the sizing action and the cationization behavior.
European Patent 0 150 754 claims colophonium resins reinforced in a special way with formaldehyde and/or &agr;,&bgr;-unsaturated carbonyl compounds and at the same time esterified with tertiary amino alcohols, and aqueous anionic dispersions of these resins.
The use of aqueous dispersions that contain colophonium resins for sizing papers has long been known and is described for instance in Casey, Pulp and Paper, 2nd Edition, Volume II: Papermaking, pages 1043-1066, Interscience Publishers, New York, 1961. The colophonium resins, such as wood rosin, balsamic resin, tall resin and the like, are typically reinforced, that is, reacted with &agr;, &bgr;-unsaturated carbonyl compounds, before they are processed into dispersions. The reaction of the colophonium resins with &agr;, &bgr;-unsaturated carbonyl compounds, such as acrylic acid, fumaric acid, maleic acid or their accessible anhydrides, is based on an adduct formation described by Diels-Alder with resin acids of suitable structure contained in the colophonium resin, and are intended to enhance the yield of the sizing agent. The thus-modified colophonium resins can then be processed into dispersions, for instance by a reversal process.
In German Published, Unexamined Patent Disclosure DE 37 08 854 A1, a sizing agent for use in the neutral range is described, which involves an aqueous dispersion of a colophonium esterified with at least one multivalent alcohol comprising carbon, hydrogen and oxygen, or reinforced colophonium. This sizing agent, in the presence of a very good retention system, does sometimes exhibit good sizing action in the neutral range when bleached sulfate cellulose is employed, but fails completely when so-called “difficult materials” are used, such as sulfite cellulose, ground wood pulp, used paper, TMP, CTMP, etc.
In German Published, Unexamined Patent Disclosure DE 44 12 136 A1, a sizing agent of reinforced colophonium, esterified with triethanolamine, is described which is dispersed with an emulsifier system comprising sodium lignin sulfonate and cationic starch. This sizing agent is intended for body or surface sizing of paper in a pH range of from 4.5 to 8.5. For producing this sizing agent, the use of high-pressure homogenizer at approximately 100° C. is prescribed. Under these dispersing conditions, both severe thermal and mechanical loading on the cationic starch used as an emulsifier or protective colloid occurs, causing a breakdown in its molecular weight. The result is poorer dispersion stability and reduced self-retention of the sizing agent when used in the papermaking machine.
In European Patent 0 259 671 B1, an aqueous dispersion of a sizing agent of reinforced, unreinforced, hydrogenated or disproportionated colophonium, optionally also esterified with amino alcohol, is described, which is dispersed with a dispersant that contains digested caseine and cationic starch. In U.S. Pat. No. 4,983,257, an aqueous dispersion of a sizing agent of reinforced, hydrogenated, disproportionated colophonium, optionally also esterified with amino alcohol, is described which is dispersed with caseine or anionic emulsifier and with cationic starch as a dispersant. For the use of the cationic starch and its effectiveness as a protective colloid and retention agent, the same objections pertain both to European Patent 0 259 671 B1 and U.S. Pat. No. 4,983,257, as have already been discussed in connection with German Patent Disclosure DE 44 12 136 A1.
In U.S. Pat. No. 5,201,994, an aqueous dispersion of a mixture of colophonium esterified with amino alcohol and reinforced colophonium, which is dispersed with a mixture of anionic emulsifier and caseine as a dispersant, is described.
It is also known that the use of resin sizings based on reinforced and/or unreinforced colophonium resin for paper sizing in the neutral range in the presence of chalk as a filler is associated with major disadvantages. For instance, the resin component, with its free carboxyl groups, can enter into reaction with the chalk, which is associated with a considerable loss of the sizing action. Furthermore, the mode of operation with dispersions on the basis of reinforced and/or unreinforced colophonium resins is associated with the use of considerable
Fallmann Johannes
Fischer Kurt
Sychra Marcel
Krems Chemis Aktiengesellschaft
Sanders Kriellion A.
Spencer George H.
Venable
Wells Ashley J.
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