Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
  • D21H17/44—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups cationic
  • D21H17/45—Nitrogen-containing groups
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/02—Chemical or chemomechanical or chemothermomechanical pulp
  • D21H11/04—Kraft or sulfate pulp
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/20—Macromolecular organic compounds
  • D21H17/33—Synthetic macromolecular compounds
  • D21H17/34—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D21H17/41—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups
  • D21H17/42—Synthetic macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing ionic groups anionic
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
  • D21H17/63—Inorganic compounds
  • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
  • D21H17/675—Oxides, hydroxides or carbonates
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/06—Paper forming aids
  • D21H21/10—Retention agents or drainage improvers
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/18—Reinforcing agents

Definitions

• the invention relates to the use of high molecular weight poly(vinyl­amines) in the papermaking process.
• Water soluble polymers such as poly(N-vinylamides), frequently re­quire high molecular weight to develop satisfactory properties for high performance applications.
• Low to medium molecular weight poly(N-vinyl­formamide) and poly(N-vinylacetamide) have been prepared by conventional solution polymerization in water and alcohols using oil-soluble and water-soluble initiators.
• poly(N-vinylamides) of high molecular weight are difficult to produce by conventional solution polymerization in that the polymer product obtained under useful conditions is a gel which is difficult to handle.
• problems with high solution viscosity and poor heat transfer make such synthesis impractical on a commercial scale.
• U.S. 3,597,314 discloses that dewatering of aqueous cellulose fiber suspension in the formation of paper is improved by adding to the suspen­sion from 0.05 to 4% of a water-soluble polymer consisting essentially of units derived from N-vinyl-N-methylformamide having 60-100% of the formic acid radicals of the polymer split off by acid hydrolysis.
• U.S. 4,623,699 discloses linear, basic polymer powders which con­tain units of the formula -CH2-CH(NH2)- and have a Fikentscher K value from 10 to 200 are prepared by eliminating the formyl groups from N-vinyl­formamide polymer powders with a gaseous hydrogen halide in the presence of not more than 5% by weight, based on the polymer used, of water.
• Polymers which contain 10-90 mole% of units of vinylamine and 10-90 mole% of units of vinyl formamide as well as poly(vinylamine) are said to be used as flocculents for waste waters and sludges and as retention agents, drainage aids and flocculents in papermaking.
• U.S. 4,500,437 discloses acrylamide copolymers and terpolymers con­taining N-vinylformamide and N-vinylacetamide prepared by inverse emul­sion polymerization in Examples 67-70 with the polymers of Examples 68 and 70 having a molecular weight below 100,000; i.e ⁇ 105.
• Example 20 shows the preparation of poly(vinylformamide) by solution polymerization.
• U.S. 4,421,602 discloses linear basic polymers containing from 90 to 10 mole% of copolymerized vinylamine units and from 10 to 90 mole% of copolymerized N-vinylformamide units.
• This patent teaches that the polymers can be prepared by solution polymerization in water, a water-­soluble solvent or a mixture of water and a water-soluble solvent and actually shows such solution polymerization in the examples. It is suggested that the polymerization can also be carried out as a water-­in-oil emulsion polymerization in a water-immiscible solvent, but there are no examples of such polymerization.
• U.S. 4,018,826 discloses the preparation of poly(vinylamine) salts of mineral acids by polymerizing vinylacetamide with a free radical poly­merization catalyst, and hydrolyzing the poly[vinylacetamide) to the de­sired amine salts by contacting the poly(vinylacetamide) with an aqueous solution of the corresponding mineral acid.
• Poly(vinylamine) product of about 3,000 to about 700,000 molecular weight (4,000 to about 1,000,000 for the salt product) is suggested.
• U.S. 3,558,581 discloses homo- and copolymers of N-vinyl-N-methyl­amine by hydrolysis of the corresponding polymers of N-vinyl-N-methyl­formamide with mineral acids.
• GB 2,152,929 is directed to a process for producing N-substituted formamides for use in producing N-vinylformamide by thermally decompos­ ing N-(alpha-alkoxyethyl)formamide in the gas phase. It is suggested that the N-vinylformamide can be bulk polymerized, solution polymerized using an aqueous solution or an organic solution, or emulsion polymerized singly or together with a monomer used conventionally for producing water-soluble polymers suitable for making flocculants, in the presence of a polymerization initiator of azo compounds. The thus obtained poly(vinylformamide) is hydrolyzed under acidic or basic conditions to obtain a cationic polymer of poly(vinylamines).
• U.S. 4,217,214 discloses that polyvinylamine hydrochloride having a molecular weight of about 5 x l05 or greater has been found to be particularly effective as a flocculating agent in wastewater systems.
• the examples disclose the use of a poly(vinylamine) hydrochloride having a molecular weight of 2 x 106 and state that the poly(vinylamine) hy­drochloride used is prepared as described in U.S. 4,018,826.
• JP 61/141712 discloses a method for producing N-vinylcarboxylic acid amide polymers by a procedure in which an aqueous solution of N-vinylcar­boxylic acid amide is dispersed in a hydrocarbon-type dispersing medium using an oil-soluble polymer dispersion stabilizer followed by radical polymerization.
• very high molecular weight poly(N-vinylamides) can be prepared by an inverse emulsion polymeriza­tion process.
• the method for preparing the inverse, or water-in-oil, emulsion involves colloidally dispersing an aqueous solution containing 10-90 wt% water-soluble N-vinylamide of the above formula in the hydrocarbon liquid using a surfactant having an HLB value from 4 to 9, the weight ratio of monomer-containing aqueous solution to hydrocarbon liquid being preferively in the range from 1:2 to 2:1, and polymerizing the monomer using an azo-type free radical initiator.
• the resultant very high molecular weight polymer emulsion has a low viscosity ranging from 2 to less than 10 cps at 15% solids, 60 rpm Brook­field and 20°C, thus eliminating problems of solution viscosity which arise when the polymer is prepared by a solution polymerization process.
• the low viscosity homopolymer emulsion is easy to handle and can be used directly.
• vinylamide homopolymer emulsions are in the pre­paration of vinylamine homopolymers of at least a 106 average molecular weight by acid or base catalyzed hydrolysis of the homopolymer, preferivelyably as the emulsion.
• the use of the mineral acid in the hydrolysis step or in acidifying the base hydrolysis product provides the poly(vinyl­amine) as the salt of such acid.
• the very high molecular weight derived poly(vinylamines) have appli­cation in the field of papermaking.
• the present invention also provides an increase in retention, drain­age rate and flocculation in a papermaking process comprising the depo­sition of a pulp stock, or cellulose fibers, to form a nonwoven sheet by adding to the pulp stock poly(vinylamines) according to the invention.
• Poly(N-vinylamides) of molecular weight at least 106, preferably 3 x 106 to 15 x 106, are prepared via an inverse emulsion polymeriza­tion process by reacting the following composition under an inert atmo­sphere:
• the aqueous solution comprising the first two components contains 10 to 90 wt%, preferably 50 to 70 wt%, of a water-soluble N-vinylamide of the formula where R and R1 represent hydrogen or an alkyl group having 1-4, preferivelyably 1-2, carbon atoms, especially a methyl group.
• the weight ratio of monomer-containing aqueous solution to hydrocarbon liquid may be varied widely depending upon the monomer used, but preferably is about 1:2 to 2:1.
• the suitable hydrocarbon liquids for use in the invention are im­miscible with water and do not significantly dissolve the monomers in the presence of water.
• Such hydrocarbon liquids are exemplified by acyclic and cyclic C5-C10 alkanes such as hexane, octane, decane, and deca­hydronaphthalene (decalin) and, in addition, certain aromatic hydro­carbons for N-vinylacetamides and the aromatic hydrocarbons toluene and xylene.
• Contemplated as the functional equivalent of toluene and xylene when R is an alkyl group in the monomer formula are ethylbenzene and tetrahydronaphthalene (tetralin).
• the preferred hydrocarbon liquids are the C5-C10 acyclic alkanes.
• the stabilizing system comprises suitable emulsifying agents, or surfactants, having a hydrophilic-lipophilic balance (HLB) value from 4 to 9, preferably 4 to 7.5, and include sorbitan fatty acid esters such as sorbitan monostearate, oleate, laurate or palmitate; polyoxyethylene-­sorbitan fatty acid esters, i.e. reaction products of one mole of the aforementioned sorbitan fatty acid esters with from 4 to 40 moles of ethylene oxide; polyoxyethylene sorbitol esters of fatty acids; and mix­tures thereof.
• the preferable quantity of surfactant is 5 to 20 wt% based on the monomer-containing aqueous solution.
• the free radical initiator should be one of the azo compounds well known in the polymerization art such as 2,2′-azobis(isobutyronitrile); 2,2′azobis(2-amidinopropane) hydrochloride; 4,4′-azobis(4′-cyano­pentanoic acid) and the like. Persulfates and hydrogen peroxide have been found not to be suitable in practicing the invention. Redox cat­alyst systems may also be used comprising the azo initiators with a reducing agent typically used in the art.
• the amount of free radical initiator can be varied widely depending upon reaction temperatures, rate of polymerization, degree of polymerization to be obtained, but preferivelyably is in the range of 0.001 to 0.5 mole% of the monomer used.
• the polymerization is usually carried out under an inert atmosphere, preferably under nitrogen.
• the reaction temperature is preferably in the range of 40-60°C.
• a high temperature, i.e. >60°C, may cause side reac­tions unfavorable to the polymer such as crosslinking or chain transfer.
• a lower temperature may be impractical because of long reaction times.
• the homopolymer product can be isolated from the emulsion by adding a flocculating agent and filtering. The precipitated product is then washed and dried. Generally, a polar organic solvent which is a good solvent for the surfactant but a poor solvent for the polymer, e.g. acetone, is used to aggregate the polymer. The precipitated polymer is filtered and washed to remove the surfactant. The dried and purified polymer of very high molecular weight is in the form of a fine powder and is water soluble.
• the vinylamide homopolymer products are hydrolyzed to vinylamine homopolymers of at least 106 average molecular weight in the presence of acids or bases. More desirably, vinylamine homopolymers of 1.8 x 106 to 9 x 106 molecular weight or more are obtained.
• the vinylamine poly­mers suitable for use as wet-end additives in the papermaking process are at least 10% hydrolyzed and desirably greater than about 50% hydrolyzed, preferably greater than about 90%, to about 99+% hydrolyzed.
• Suitable acids for the hydrolysis include mineral acids such as hydrochloric, hydrobromic, sulfuric, phosphoric and perchloric acid; and organic acids such as trifluoroacetic acids and methanesulfonic acid.
• the bases which can be employed include alkali and alkaline earth hy­droxides such as sodium hydroxide, potassium hydroxide, calcium hydroxide and barium hydroxide; and quaternary ammonium hydroxides such as tetra­methyl ammonium hydroxide.
• the quantity of the acid or base required may vary widely, depending upon the degree of hydrolysis desired and reaction conditions. Approximately, 1 to 3 equivalents of the acid or base per equivalent of the polymer is preferred to achieve essentially complete hydrolysis.
• the hydrolysis can be performed in various solvents, including water; liquid ammonia; alcohols such as methanol, ethanol, isopropanol, and t-butanol; amines such as methylamine, dimethylamine ethylamine and the like; and hydroxy amines such as ethanolamine.
• solvents including water; liquid ammonia; alcohols such as methanol, ethanol, isopropanol, and t-butanol; amines such as methylamine, dimethylamine ethylamine and the like; and hydroxy amines such as ethanolamine.
• the temperature of the hydrolysis may range from 20 to 200°C depending upon the type of polymer and hydrolysis employed. Generally, hydrolysis proceeds more rapidly for poly(N-vinylformamide) than for poly(N-vinylacetamide). Thus, hydrolysis of poly(N-vinylformamide) can be carried on under milder conditions, i.e. at lower temperatures and shorter reaction times than for poly(N-vinylacetamide).
• the preferable temperature range of a base hydrolysis is 70 to 100°C which is lower than that of acid or base hydrolysis of N-vinylacetamide in the range of 110 to 200°C.
• the hydrolyzed polymer products thus obtained comprise the repeating free amino-containing units of the formula in the case of base hydrolysis, and amino-containing units of the formula in the case of acid hydrolysis, where X ⁇ represents the anion corres­ponding to the acid employed in the hydrolysis.
• Poly(vinylamine) is preferably isolated in the salt form to prevent adsorption of atmospheric carbon dioxide.
• the polymer salt is isolated by acidifying the hydrolysis mixture to cause the polymer to precipitate.
• the precipitated polymer generally is a gum, but a fibrous material can be obtained after redissolving, followed by reprecipitation in methanol.
• the products of this invention are high molecular weight poly(N-­vinylamides), especially poly(N-vinylformamide) of 3-15 x 106 mol wt and poly(N-vinylacetamide) of 1.3-5 x 106 mol wt, and the derived poly(vinylamine) and poly(vinylamine) salts.
• polymeric materials may also contain up to 25 wt% copolymer­izable monomers such as, for example, acrylamide, N-vinyl-pyrrolidone, sodium vinyl sulfonate and acrylamidomethylpropane sulfonic acid (sodium salt), provided the polymer maintains sufficient water solubility.
• copolymer­izable monomers such as, for example, acrylamide, N-vinyl-pyrrolidone, sodium vinyl sulfonate and acrylamidomethylpropane sulfonic acid (sodium salt), provided the polymer maintains sufficient water solubility.
• aqueous cellulose fiber (wood pulp) suspension which may contain one or more rosin size and mineral constituents (fillers) depending on the prod­uct desired, being deposited and drained on a continuously moving wire cloth.
• the free water passes and drops off the cellulose fiber web which undergoes further processing to yield the desired paper product.
• the ad­dition of 0.05 to 0.5 wt%, preferably 0.1 to 0.2 wt%, vinylamine polymer, based on fiber, to the aqueous cellulose fiber slurry (wet-end) provides for an increase in the dry strength of the paper product and an increase in the retention of titanium dioxide in those papermaking processes that use TiO2.
• This Example shows a preparation of a very high molecular weight poly(N-vinylformamide) by inverse emulsion polymerization.
• Sorbitan monostearate (SPAN 60 surfactant, HLB 4.7, 2.5g) was dis­solved in octane (90g) and the resulting solution was transferred to a reaction kettle.
• the reactor was purged with nitrogen and kept in a nitrogen atmosphere throughout the polymerization.
• the N-vinylformamide solution (15g in 30g of water) was degassed and added to the reactor at the rate of 2.5 ml/min with vigorous agitation. (The N-vinylformamide was purified by vacuum distillation at 70°C, 1 torr, prior to use.) While the reaction mixture was heated to 50°C, 2,2′-azobis(2,4-dimethyl pentanitrile) (Vazo 52 initiator, 0.05g) was charged.
• the solid polymer product was recovered by breaking the emulsion by the addition of acetone.
• the isolated N-vinylformamide homopolymer had a molecular weight of 6.7 x 106 as measured by light scattering and a viscosity of 21,000 cps as a 5% aqueous solution.
• the vinylformamide homopolymer (10g) of Example 1 was dissolved in water (990g) and then mixed with 50% aqueous sodium hydroxide (11.3g). The resulting mixture was heated for 8 hours at 80°C under a nitrogen atmosphere. To the reaction mixture was added concentrated hydrochloric acid until the polymer precipitated. The acid solution was decanted. The precipitated polymer was redissolved in water and reprecipitated with methanol.
• the vinylamine homopolymer hydrochloride salt had a viscosity of 400 cps at 1% aqueous solution.
• This Example shows the preparation of a very high molecular weight poly(N-vinylacetamide) by inverse emulsion polymerization.
• the N-vinylacetamide was prepared according to the method taught in U.S. Patent 4,018,826.
• the N-vinylacetamide was purified as follows: The crude N-vinylacetamide (1 kg) was flash distilled at 70-74°C, 1 torr. Approximately two-thirds of the material was distilled to give a 70:30 N-vinylacetamide/acetamide mixture. This mixture (100g) and toluene (600g) were placed in a 1000 ml beaker and the resulting mixture was stirred well. The yellow toluene solution was decanted from insoluble solids which were washed twice with 50g of fresh toluene.
• the toluene solutions were combined and washed with 25g of brine. The yellow brine solution was discarded. The toluene solution was then extracted four times with 130 ml of water. The aqueous solution was back extracted with 25 ml of methylene chloride. The methylene chloride solution was dis­carded. The aqueous solution was saturated with sodium chloride and ex­tracted four times with 330 ml methylene chloride. After removing the methylene chloride under reduced pressure, 42g of pure N-vinylacetamide (60% recovery) was obtained.
• N-vinylacetamide 15g
• water 45g
• xylene 90g
• SPAN 60 surfactant 4g
• the N-vinylacetamide homopolymer was precipitated by addition of acetone, and had a molecular weight of 1.5 x 106, as determined by gel permeation chromatography.
• N-vinylacetamide homopolymer of Example 3 (10 g) was dissolved in water and mixed with concentrated hydrochloric acid (2 mole equiv­alents). The resulting mixture was heated to reflux (about 110°C) for 48 hours. To the reaction mixture was added concentrated hydrochloric acid until the polymer precipitated. The acid solution was decanted. The precipitated polymer was redissolved in water and reprecipitated with methanol yielding 8.8g of product having a viscosity of 324 cps as a 1 % aqueous solution.
• NVF N-vinylformamide
• This Example demonstrates the use of the vinylamine homopolymer as a dry strength additive in paper making application.
• Paper chromatography grade stock of uniform size was immersed in water, metered through squeeze rolls and weighed. Water pick-up was calculated and determined consistent from sheet to sheet. The weight of polymer required per unit water volume to impart 0.5% polymer pick-up on sheet weight (dry/dry) was determined.
• the low molecular weight (80M) vinylamine homopolymer and polyvinyl alcohol were applied at 0.75%.
• the high molecular weight (7MM) vinyl­amine homopolymer which was an extremely high 3200 cps in viscosity was diluted to 0.188% solids and assumed to be 0.125%, the add-on level of the others.
• the polymers were adjusted to pH 4.5 prior to sheet satura­tion.
• This Example shows the retention characteristics of the vinylamine homopolymer in papermaking.
• softwood and hardwood bleached kraft pulps were each suspended at 1.5% consistency in deionized water.
• the pulps were then blended 1:1 by weight and an amount equiv­alent to 30g (oven dry basis) was utilized in preparing each set of hand sheets.
• Ten percent of anatase TiO2 based on fiber weight was added followed by 5 minutes of stirring. (The TiO2 was predispersed at 10% solids in deionized water).
• Sufficient pulp to form a 2.5g hand sheet was removed and treated with polymer followed by 30 seconds of moderate stirring.
• the treated fiber suspension was then added to a Noble and Wood sheet mold containing sufficient deionized water to provide a form­ing consistency of 0.04%.
• Hand sheets formed from the fiber suspensions were pressed 5 minutes at 50 psig between blotter stock and then drum dried 7 minutes at 220°F in contact with one blotter.
• the present invention provides very high molecular weight poly(N-­vinylamides) by inverse emulsion polymerization and derived poly(vinyl amines) having application in the wet-end of the papermaking process.

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• 1989
  • 1989-02-24 EP EP89103305A patent/EP0331047A1/en not_active Withdrawn
  • 1989-03-02 FI FI890994A patent/FI890994A/fi not_active Application Discontinuation
  • 1989-03-03 JP JP5018189A patent/JPH026685A/ja active Pending

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