GB1406336A - Process for the treatment of paper pulp - Google Patents

Abstract

1406336 Treatment of paper pulp RHONEPOULENC SA 25 May 1973 [26 May 1972] 25047/73 Heading D2B [Also in Division C3] Paper pulp is treated directly on a paper making machine with an aqueous emulsion containing at least one organosilicon polymer wherein the emulsion contains in an amount of 5-40% of the weight of the total organosilicon polymer content an organic condensate which can be cured for sizing the paper. The organic condensate is obtained by reacting (a) an amine type polymer containing units of the general formula: wherein X is an integer from 1 to 7, R is a hydrogen atom or an alkyl radical with 1 to 4 carbon atoms and may be the same or different in each C n H 2n NR group when X is greater than 2, and A is a divalent radical of the formula -CO-, -CS-, -CO-Q- or -CO-Q'-CO- in which Q is an alkylene radical with 2 to 6 carbon atoms and Q' is a saturated or unsaturated linear or branched, divalent organic radical; with (b) an epihalohydrin or a compound containing at least one halohydrin group. The organosilicon polymer can be chosen from (a) methylhydrogenopolysiloxanes of viscosity ranging from 2 cPo at 25‹C to 5000 cPo at 25‹C corresponding to the general formula in which R', which may be the same or different represents a methyl group or a hydrogen atom, a represents an integer in the range 3 to 600, and b represents zero or an integer in the range 1 to 200; (b) dimethylpolysiloxane oils and rubbers corresponding to the general formula in which R", which may be the same or different, represents a methyl group, a hydroxyl radical or a lower alkoxy radical with 1-4 carbon atoms, and c represents an integer in the range 5-20000; and (c) methylpolysiloxane resins which are liquid, solid or paste like products which may .be dissolved in toluene, xylene, cumene, cyclohexane, methylcyclohexane and alkenes with 5 to 20 carbon atoms. They are formed from a succession of units of formula SiO 2 , CH 3 SiO 1 . 5 , (CH 3 ) 2 SiO and (CH 3 ) 3 SiO 0 . 5 , which are distributed so that the resins possess 0.9 to 1.9 methyl group per silicon atom. They can further contain up to 25% by weight of hydroxyl and/or alkoxy groups such as methoxy, ethoxy, isoproxy, n-butoxy and isobutoxy groups bonded to silicon atoms. Emulsifying agents of an amount up to 20% of the weight of the organo silicon polymer may be used to facilitate emulsification of the polymers, possible agents including (1) non- ionic agents such as alkyl-phenyl monoethers of polyalkylene glycol, the products of the reaction between fatty alcohols of amides of fatty acids and ethylene oxide, and a polyvinyl alcohol and (2) cationic agents such as salts of aliphatic amines and quarternary ammonia, pyridinium salts which possess long hydrocarbon chains, and the products of the reaction of fatty acids with N, N-dialkyl-amino-alcohols. The curing of the organosilicon polymers which contain hydroxyl or alkoxy groups may be accelerated by the addition of catalysts of weight 0.1-80% that of the polymers. The catalysts are preferably added seperately to the paper pulp in the form of aqueous emulsions or solution. The catalysts used include metal and organometallic salts of carboxylic acids such as zinc, lead, cobalt, tin, iron and dialkyl-tin salts of carboxylic acids e.g. acetates, zinc, lead, tin, or iron 2-ethyl-hexanoate, dibutyl-tin dilaurate or dioctyl-tin dilaurate, dibutyl or dioctyl-tin diacetate and dibutyl-tin maleate; chelates prepared from beta-diketones or beta-keto-esters and metal derivatives such as iron and totanium acetylacetonates, alkyl titanates such as propyl, isopropyl, butyl, isobutyl, hexyl, 2-ethyl hexyl and octyl titinate; and complexes obtained by reacting alkyl titanates or titanium tetrachloride with carboxylic acid anhydrides or alkanolamines such as the titanates of acetic anhydride and of triethanolamine. When resinous organosilicon polymers are incorporated, they may be, prior to emulsification, dissolved in toluene, xylene, cyclohexane or methylcyclohexane. The paper pulp may be natural or regenerated cellulosic fibres and may originate from the wood of deciduous trees or conifers, from rags or from straw and may be bleached. Synthetic fibres may also be incorporated. The paper product preferbaly contains 0.1 to 3% by weight of organosilicon polymers, and possesses hydrophobic, non-stick and electrical insulating properties.