Use of dispersions of cationic copolymers for paper sizing

    公开(公告)号:GB976548A

    公开(公告)日:1964-11-25

    申请号:GB4415362

    申请日:1962-11-22

    Applicant: BASF AG

    Abstract: A dispersion for the stock sizing or surface sizing of paper comprises a polymer of (a) 4 to 40% of a quaternary vinylimidazolinium salt of formula where R2 is an alkyl, aralkyl or hydroxyalkyl group, R1 is aryl or R2 and Y is a radical of a strong acid which salt may be substituted in the 4- and 5-positions with low molecular weight alkyl groups and (b) at least 20% of an ester of formula where R3 is hydrogen or a C1-4 alkyl and R4 is a C2- 8 alkyl, (c) acrylonitrile and/or (d) one or more other ethylenically unsaturated polymerizable compounds. Preferred proportions are 7-20% of the salt, 40-80% of the ester and 20-50% of the acrylonitrile. Details of the preparation are given in Specification 976,547. Specification 897,804 also is referred to.ALSO:Paper is stock sized or surface sized with a dispersion of a copolymer of (a)4-40% of a quaternary vinylimidazolinium salt of formula:- where R2 is an alkyl, aralkyl or hydroxyalkyl group, R1 is R2 or aryl and Y is a radical of a strong acid, which salt may be substituted in the 4-or 5-position with low molecular weight alkyl groups and (b) at least 20% of an ester of formula:- where R3 is hydrogen or a C1-4 alkyl and R4 is a C2-3 alkyl (c) acrylonitrile and/or (d) one or more other ethylenically unsaturated polymerizable compounds. Preferred proportions are 7-20% of the salt 40-80% of the ester and 20-50% of the acrylonitrile. Specified paper are kraft, writing, printing and tissue papers and papers containing plastics fibres. The solids content of the dispersion may be from 2 to 20% for stock sizing and 0 5 to 5% for surface sizing. The dispersions may be added to the aqueous paper pulp, or at any point in the paper machine. It is particularly simple to apply the dispersion by means of a sizing press incorporated in the dry end of the paper machine. Also, finished paper if undersized, may be resized in a simple aftertreatment e.g. in a coating machine. In examples the dispersions are used to treat strips of unsized paper from 100% bleached sulphite pulp by dipping the paper in the dispersion and the dispersion is added to an aqueous suspension of bleached sulphite pulp and the mixture made into paper. Specifications 897,804 and 976,547 are referred to.

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