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
1993-04-26
1994-02-22
Michl, Paul R.
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...
524563, 524564, C08L 9324, C08L 3102, C08L 3902, C08L 3100
Patent
active
052887820
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to novel rosin emulsion sizing agents for papermaking and more particularly to rosin emulsion sizing agents for papermaking which are prepared using a specific copolymer as a dispersant.
BACKGROUND ART
In view of the desirability for a closed papermaking system, rosin emulsion sizing agents for papermaking are in predominant use in recent years. Consequently extensive investigations have been made on dispersing agents for use in preparing the rosin emulsion sizing agents. Conventional dispersants include low-molecular-weight dispersants such as sodium alkylsulfonates, sodium alkylbenzenesulfonates, polyoxyethylene alkyl phenyl ethers and sulfuric acid ester salts of polyoxyethylene alkyl phenyl ethers. However, emulsion sizing agents prepared using the low-molecular-weight dispersant markedly bubble up when used for papermaking and fail to produce a satisfactory sizing effect when used for papermaking at high temperatures or high pH values. Rosin emulsion sizing agents have been developed in which a polymer dispersant is used to obviate the drawbacks of the low-molecular-weight dispersants. These sizing agents are substantially free of bubbling in papermaking, but still unsatisfactory in sizing effect when used for papermaking at high temperatures or high pH values.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a novel rosin emulsion sizing agent which is usable for papermaking free of the foregoing prior art drawbacks.
It is another object of the invention to provide a papermaking rosin emulsion sizing agent which is effectively usable over a wide pH range, serviceable without decrease of sizing degree even when used in papermaking at high temperatures, less susceptible to bubbling and easy to handle in use.
These and other objects of the invention will become more apparent from the following description.
According to the present invention, there are provided:
(1) a rosin emulsion sizing agent for papermaking, comprising a rosin substance, a dispersant and water, the sizing agent being characterized in that the dispersant is a copolymer comprising (A) 20 to 90% by weight of a vinyl carboxylate, (B) 1 to 60% by weight of an anionic unsaturated monomer and (C) 1 to 60% by weight of a cationic unsaturated monomer; and
(2) a rosin emulsion sizing agent for papermaking, comprising a rosin substance, a dispersant and water, the sizing agent being characterized in that the dispersant is a copolymer comprising (A) 20 to 90% by weight of a vinyl carboxylate, and (B) 10 to 80% by weight of an anionic unsaturated monomer or (C) 10 to 80% by weight of a cationic unsaturated monomer.
To overcome the foregoing prior art drawbacks, the present inventors conducted extensive research with attention directed to dispersants for use in dispersing a rosin substance in the preparation of a rosin emulsion sizing agent for papermaking. As a result, their research revealed the following. When a rosin substance is dispersed in water in the presence of said dispersant, namely the above-specified copolymer containing a vinyl carboxylate as an essential monomer, the papermaking rosin emulsion sizing agent obtained is less susceptible to bubbling or foaming, is suitably usable even in papermaking over a wide pH range and is serviceable without decrease of sizing degree even in papermaking at high temperatures. The present invention has been accomplished based on this novel finding.
The rosin substance to be dispersed in the present invention is one comprising 0 to about 95% by weight of a rosin, and about 5 to about 100% by weight of a rosin derivative, optionally together with up to 50% by weight of an extender.
Examples of useful rosins are gum rosin, wood rosin, tall oil rosin and the like. These rosins can be used singly or at least two of them are usable in mixture. Examples of useful rosin derivatives are hydrogenated rosins, disproportionated rosins, polymerized rosins, aldehyde-modified rosins and like modified rosins, fortified rosins, rosi
REFERENCES:
patent: 4115331 (1978-09-01), Tominaga et al.
patent: 4129711 (1978-12-01), Viout et al.
patent: 4294873 (1981-10-01), Hartmann et al.
patent: 4943608 (1990-07-01), Takahashi et al.
Nakajima Masato
Sakai Itsuro
Tani Nobuyuki
Arakawa Chemical Industries Ltd.
Michl Paul R.
Szekely Peter
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