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...
Patent
1991-12-09
1994-11-22
Lovering, Richard D.
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...
106236, 106238, 162180, 252311, 252312, 252314, 252356, 252357, C08J 321, C08L 9300, B01F 1718, B01J 1300
Patent
active
053670094
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a dispersant composition containing a defined polymer, which is suitable for the production of aqueous rosin emulsion, and an aqueous rosin emulsion containing said dispersant composition. The invention further relates to an emulsion size containing said aqueous rosin emulsion as an active ingredient.
BACKGROUND ART
Rosins have heretofore been employed in a diversity of applications including, inter alia, paper size, tackifier, rubber emulsifier, coatings, printing ink and so on. Recently, from the standpoints of safety and environmental protection, much attention has been focused on the technology of providing rosins in aqueous emulsion forms. Particularly in the field of sizing agents, improvements have been sought in aqueous rosin emulsions.
Cellulosic fiber products such as paper, cardboard, wood fiber board, etc. are generally manufactured in web-forming systems using size-containing aqueous dispersions of cellulosic fibers, and with regard to the sizing agents used for this purpose, saponified and fortified rosin sizes are commonly employed because they impart water resistance, resistance to bleeding, etc. to final sheets. However, such fortified rosin sizes cannot be properly used in high-temperature web-making processes. The recent rigorous control over effluent disposal calls for a closed papermaking system but the resulting increase in the temperature of papermaking water detracts from the effect of sizes. In the case of neutral paper which is lean in alum, i.e. aluminum sulfate, too, the effect of sizes is inadequate.
Therefore, in recent years, as substitutes for such fortified rosin sizes, rosin emulsion sizes which resolve many of the above problems have been used in preponderance in this field. Several methods are known for the production of such emulsion sizes. They include the method which comprises dispersing a fortified rosin in water in the presence of a suitable dispersing agent using a high-pressure shear homogenizer, the method in which a molten fortified rosin is subjected to phase inversion using a suitable dispersing agent and water, and the method comprising dissolving a fortified rosin in a solvent and emulsifying the solution with a dispersing agent and water. Among the dispersing agents which are generally used in the production of such emulsion sizes are sodium alkylsulfate, sodium alkylbenzenesulfonate, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylphenyl ether sulfate, etc. However, emulsion sizes prepared with these known dispersing agents, which are invariably of low molecular weight, have the drawback of producing a copious foam in the process of web formation, although in sizing effect they are superior to said saponified and fortified rosin sizes. Moreover, these emulsion sizes are not satisfactory enough in sizing effect in high-temperature or high-pH systems.
More recently, much research and development work has been undertaken in the field of rosin emulsion sizes employing polymeric dispersing agents (Examined Japanese Patent Publication No. 48031/1984 and Unexamined Japanese Patent Publications No. 169898/1981 and No. 108796/1986). Rosin emulsion sizes obtainable with such polymeric dispersing agents are satisfactory in that they produce no appreciable foam but are still deficient in sizing effect in a high-temperature or high-pH web formation system.
BRIEF SUMMARY OF THE INVENTION
It is an object of the invention to provide a dispersant composition for use in the production of an aqueous rosin emulsion, an aqueous rosin emulsion containing said dispersant composition, and an emulsion size containing said aqueous rosin emulsion as an active ingredient, all overcoming the disadvantages of the prior art technologies mentioned hereinbefore.
It is another object of the invention to provide a rosin emulsion size which can be effective over a broad pH range, does not suffer a decrease in sizing performance even in high-temperature web-forming systems, and features a low foam profile and an improved ease of
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Inoue Tetsuya
Sasaki Yoshihiro
Yoshimura Hirofumi
Arakawa Chemical Industries Ltd.
Lovering Richard D.
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