KR950009738B1 - Papermaking process and papermaking additive - Google Patents

Abstract

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Description

[Name of invention]

Papermaking method and paper additive

Detailed description of the invention

[Technical Field]

The present invention relates to a papermaking method, and more specifically, to using a cationic acrylamide polymer obtained by Hoffman decomposition reaction in a short time at a high temperature and a cationic polyacrylamide produced by anionic inorganic material or copolymerization. It relates to a paper or a method characterized in that the paper and the cationic acrylamide polymer obtained by Hoffman decomposition reaction, and an anionic inorganic material or cationic polyacrylamide produced by copolymerization.

[Background]

In recent years, due to the worsening of raw material situation, the ratio of used paper as a pulp raw material tends to increase, and it is required to increase the strength of the intellect with respect to the strength enhancer. On the other hand, also in the operation surface, the chemical | medical agent which improves the dehydration rate of a pulp, and forms the filtrate more, or the chemical | medical agent which improves drying property by reducing the usage-amount of steam is called for.

Hoffman decomposition reaction product of polyacrylamide (hereinafter Hoffman PAM) is a cationic resin having a primary amino group directly bonded to the polymer main chain, and has been used as a filtrate enhancer or an intelligence enhancer in the paper manufacturing process. The characteristic of Hoffman PAM is the strength of cohesion, but it does not only improve the freeness but also improves the strength between fibers by hydrogen bonding of the primary amino group, which is also a cation. However, when Huffman PAM is used alone, effective fixation to pulp fibers may not be achieved depending on the papermaking conditions, and sometimes the characteristics of Hoffman PAM cannot be sufficiently exhibited. In such a case, the aspect of the freeness is solved by increasing the amount of Hoffman PAM added, but on the other hand, the paper quality is deteriorated, and thus, the results of paper strength and printing characteristics are not necessarily satisfactory.

[Initiation of invention]

In view of the above, the present inventors have studied various additives having a co-adding effect with Hoffman-decomposed PAM, and as a result, in combination with an anionic inorganic material or a cationic acrylamide polymer produced by copolymerization, The present invention was found by finding that controllability can be controlled without lowering.

That is, the present invention is a cationic acrylamide polymer and an anionic inorganic material obtained by reacting acrylamide polymer and hypohalogen acid salt in a alkaline range in a temperature range of 50-110 ° C for a short time, or (a) general formula (I) )

And a cationic monomer represented by (wherein, R ₁ is hydrogen or methyl group, R ₂ , R ₃ is hydrogen or alkyl group having 1-6 carbon atoms, X is O or NH, n is an integer of 2-4) and / or Quaternary ammonium salts obtained by reaction of salts of these organic to inorganic acids or of general formula (1) with a quaternizing agent, (b) α, β-unsaturated carboxylic acids and / or their Salts, and (c) general formula (II)

CH ₂ = C (R ₅ ) -CONH ₂

A cationic polyacrylamide obtained by copolymerizing an acrylamide monomer represented by formula (wherein R ₅ represents hydrogen or a methyl group) is added to the pulp slurry in combination with a papermaking method and an acrylamide system under an alkaline region. Cationic acrylamide-based polymer and anionic inorganic material obtained by reacting polymer and hypohalogenate in temperature range of 50-110 ° C in a short time, or (a) general formula (I)

And a cationic monomer represented by (wherein R ₁ is hydrogen or methyl group, R ₂ , R ₃ is hydrogen or alkyl group of 1-6 carbon atoms, X is O or NH, n is an integer of 2-4) and / or Quaternary ammonium salts obtained by reaction with salts of these organic to inorganic acids or with general formula (I) and a quaternizing agent, (b) alpha, beta -unsaturated carboxylic acid and / or salts thereof, (c) ) Formula (II)

CH ₂ = C (R ₅ ) -CONH ₂

The formula relates to a papermaking additive composed of a cationic polyacrylamide obtained by copolymerizing an acrylamide monomer represented by (wherein R ₅ represents hydrogen or a methyl group).

Hereinafter, the present invention will be described in detail.

The acrylamide polymer used in the present invention is a homopolymer of acrylamide (or methacrylamide), a copolymer of at least one unsaturated monomer copolymerizable with acrylamide (or methacrylamide), or a water-soluble polymer such as starch. It refers to the graft copolymer to.

As a monomer which can be copolymerized, a hydrophilic monomer, an ionic monomer, a lipophilic monomer, etc. are mentioned, One or more types of those monomers are applied. Specifically as a hydrophilic monomer, for example, diacetone acrylamide, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N-ethyl methacryl amide, N-ethyl acrylamide, N, N-di Ethyl acrylamide, N-propyl acrylamide, N-acryloyl phyllolidine, N-acryloyl piperidine, N-acryloyl morpholine, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxy Propyl methacrylate, hydroxypropyl acrylate, various methoxy polyethylene glycol (meth) acrylates, N-vinyl-2-pyrrolidone, and the like.

As the ionic monomer, for example, acrylic acid, methacrylic acid, vinyl sulfonic acid, allyl sulfonic acid, metharyl sulfonic acid, styrene sulfonic acid, 2-acrylic amido-2-phenyl propane sulfonic acid, 2-acrylic amido-2-methylpropanesulfonic acid Acids and salts thereof, such as N, N-dimethyl aminoethyl methacrylate, N, N-diethyl aminoethyl methacrylate, N, N-dimethyl aminoethyl acrylate, N, N-dimethyl amino propyl methacrylamide And amines such as N, N-dimethylamino propyl acrylamide and salts thereof.

Examples of lipophilic monomers include N, N-di-n-propylacrylamide, Nn-butyl acrylamide, Nn-hexyl acrylamide, Nn-hexyl methacrylamide, Nn-octyl acrylamide, and Nn-octyl-meta. N-alkyl (meth) acrylamide derivatives such as krylamide, N-tert-octyl acrylamide, N-dodecyl acrylamide, Nn-dodecyl methacrylamide, N, N-diglycidyl acrylamide, N, N-diglycidyl methacrylamide, N- (4-glycidoxybutyl) acrylamide, N- (4-glycidoxybutyl) methacrylamide, N- (5-glycidoxypentyl) acrylamide, N- (W-glycidoxyalkyl) (meth) acrylamide derivatives such as N- (6-glycidoxyhexyl) acrylamide, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acryl (Meth) acrylates such as lauryl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate Derivatives, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, olefins such as ethylene, propylene, butene, styrene, divinylbenzene, α-methylstyrene, butadiene, isoprene, and the like. .

The amount of the unsaturated monomers provided for the copolymerization varies depending on the type of unsaturated monomers and combinations thereof, and can not be generally stated, but is generally in the range of 0-50% by weight.

Moreover, as a water-soluble polymer which graft-polymerizes the said monomer, any natural type and synthetic type can be used. Modified products such as starch and oxidized starch, carboxyl starch, dialdehyde starch, cationic starch derived from various kinds of natural origin, cellulose derivatives such as methyl cellulose, ethyl cellulose, carboxy methyl cellulose, hydroxy ethyl cellulose, arginic acid, agar, Pectin, carrageenan, dextran, fururan, konjac, gum arabic, casein, gelatin and the like. Examples of the synthetic system include polyvinyl alcohol, polyvinyl ether, polyvinylpyrrolidone, polyethyleneimine, polyethylene glycol, polypropylene glycol, polymaleic acid copolymer, polyacrylic acid, polyacrylamide, and the like. The amount of the monomer added to the above water-soluble polymer is in the range of 0.1-10.0 times based on the weight of the water-soluble polymer.

Next, the above monomers are polymerized to produce polyacrylamide. As the polymerization method, radical polymerization is preferable, and as the polymerization solvent, polar solvents such as water, alcohol, dimethylformamide and the like are applicable. However, aqueous solution polymerization is preferable because Hoffman decomposition reaction is performed in an aqueous solution. The monomer concentration at that time is 2-30 weight%, Preferably it is 5-30 weight%. The polymerization initiator is not particularly limited as long as it is water-soluble, and is usually used after being dissolved in an aqueous monomer solution. Specifically, in a peroxide type | system | group, ammonium persulfate, potassium persulfate, hydrogen peroxide, tert- butyl peroxide etc. are mentioned, for example. In this case, although it can use alone, it is used also as a redox-type polymerizer in combination with a reducing agent. Examples of the reducing agent include salts of metals with low ionization tendency, such as sulfite, hydrogen sulfite, iron, copper, and cobalt, and organic amines such as N, N, N ', and N'-tetramethyl ethylenediamine, aldose, ketose, and the like. And reducing sugars.

Moreover, as an azo compound, 2, 2'- azobis-2- amidino propane hydrochloride, 2, 2'- azobis-2, 4-dimethyl valeronitrile, 4, 4'- azobis-4- cyano Valeric acid and its salts can be used. Moreover, it is also possible to use 2 or more types of said polymerization initiators together. In the case of graft polymerization to a water-soluble polymer, in addition to the polymerization initiator described above, it is also possible to use transition metal ions such as second cerium ions and ferric ions, and may be used in combination with the polymerization initiator. . The amount of the initiator added is 0.01-10% by weight, preferably 0.02-8% by weight based on the monomers. In the case of the redox system, the amount of the reducing agent added to the initiator is 0.1-100% on the molar basis, preferably 0.2-80%.

The polymerization temperature is somewhat lower at about 30-90 ° C. for homopolymerization initiators and is usually lower at −5-50 ° C. for redox-based polymerization initiators. Moreover, it is not necessary to maintain the same temperature during superposition | polymerization, You may change arbitrarily according to the progress of superposition | polymerization, and generally raises the temperature by the heat of superposition | polymerization which generate | occur | produces with advancing of superposition | polymerization. At this time, the atmosphere in the polymerization reactor is not particularly limited, but in order to accelerate the polymerization, it is better to substitute an inert gas such as nitrogen gas. The polymerization time is not particularly limited but is usually 1-20 hours.

Next, the polyacrylamide prepared by the above method undergoes Hoffman decomposition reaction. In that case, when the preparation is made into aqueous solution, the polyacrylamide used as a raw material can be diluted as it is or as needed, and can be used for reaction. In the case of the graft copolymer, ungrafted polyacrylamide is also a by-product, but since it is usually not separated, it is used for the reaction as it is.

The Hoffman decomposition reaction is performed by acting a halogenated acid salt on the amide group of polyacrylamide in the presence of an alkaline substance. Examples of the hypohalogenated acid include hypochlorous acid, hypobromic acid and hypoiodic acid. Examples of the hypochlorite include metals of hypochlorous acid and alkaline earth metal salts, and specific examples thereof include sodium hypochlorite, potassium hypochlorite, lithium hypochlorite, calcium hypochlorite, magnesium hypochlorite and barium hypochlorite. Likewise, for the hypobromite and hypoiodic salts, there may be mentioned alkali metal or alkaline earth metal salts of hypobromite and hypoiodine. It is also possible to blow halogen gas into the alkaline solution to produce hypohalogenate. Alkali metal hydroxides, alkaline earth metal hydroxides, alkaline earth metal hydroxides, alkali metal carbonates and the like are exemplified by the alkaline substances. Among them, alkali metal hydroxides are preferable, and sodium hydroxide, potassium hydroxide, lithium hydroxide and the like can be given. . The amount of the above-mentioned substance added to the polyacrylamide is 0.05-2.0 mol, preferably 0.1-1.5 mol, with respect to the amide group as hypohalogen acid, and 0.05-4.0 mol, preferably 0.1-3.0, with respect to the amide group as the alkaline substance. It's a mole. The pH at that time is usually in the range of 11-14. The concentration of polyacrylamide at that time is usually 0.1-17.5% by weight, but in consideration of the difficulty in stirring and the gelation that easily causes gelation when the reaction temperature is high, it is usually preferably in the range of 0.1-10% by weight. . In addition, when the reaction concentration is less than 1%, there is a problem that the reaction rate is slow, and therefore it is more preferable that it is 1-10% by weight.

On the other hand, the reaction temperature is in the range of 50-110 ° C, preferably in the range of 60-100 ° C. The Hoffman decomposition reaction is performed in a short time within the above temperature range. Since the reaction time depends on the reaction temperature and the polymer concentration in the reaction solution, it cannot be said uniformly. For example, when the polymer concentration is 1% by weight, it is within 10 minutes at 50 ° C, within minutes at 65 ° C, and at 80 ° C. Within tens of seconds is enough. The higher the polymer concentration, the shorter the reaction time.

The relationship between reaction time and reaction temperature should just be in the range between the following two relational formulas, and if it reacts in the range, a preferable result will be obtained.

T: reaction temperature (℃)

50≤T≤110

Cationic polyacrylamides prepared under the above conditions usually have a cation equivalent measured by colloid titration at pH 2 in the range of 0-10.0 meq / g, and the cation equivalent can be controlled by the addition amount of hypohalogenate. There is a number. In addition, since the reaction takes place in the alkaline region, the amide group is hydrolyzed to produce a carboxyl group. The by-product amount is expressed as anion equivalents measured by colloid titration at pH 10, usually in the range of 0-10.0 meq / g. The amount of by-product becomes controllable by the amount of alkaline substance to add.

After the reaction under the above conditions, it is preferable to stop the reaction in order to suppress the progress of the side reaction. However, when used immediately after the reaction may not need to stop the reaction.

As a method of stopping the reaction, (1) a reducing agent is added. It can be used individually or in combination, such as (2) cooling, and (3) reducing the pH of a solution by acid addition. (1) is a method of inactivating residual hypohalogenate etc. by reaction with a reducing agent. In general, at the end of the Hoffman decomposition reaction, compounds having an active chlorine such as unreacted hypohalogenate remain. When such a reaction solution is used as an intelligence agent, it causes a rust of the paper machine. Therefore, in general, active chlorine is inactivated by using a reducing agent. However, hypohalogenate reacts with the number of moles of acrylamide units of the polymer at less than molar moles, and when reacted at a high temperature, almost unreacted hypohalogenate remains at the end of the reaction. Therefore, it is also possible to use it as an intelligent agent, without deactivating active chlorine using a reducing agent. (2) is a method of suppressing reaction progress by cooling, in which the method is cooled by using a heat exchanger. And dilution with cold water. The temperature at that time is 50 degrees C or less normally, Preferably it is 45 degrees C or less. In (3), the Hoffman decomposition reaction is stopped by reducing the pH using an acid in the solution at the end of the reaction which usually shows an alkalinity of pH 12-13, and at the same time, the progress of the hydrolysis reaction is suppressed. PH at this time should just be neutral or less, Preferably it is the range of pH 4-6. The reaction stopping method can be arbitrarily selected according to the reaction conditions from (1)-(3), and these methods may be combined.

The anionic inorganic material co-added with Hoffman's decomposed PAM prepared by the above method is oxygen silicate. Anionic particulate inorganic materials or mixtures thereof. Sodium silicate is obtained by melting silicon dioxide and sodium carbonate or caustic soda at high temperature, and what is usually sold as water glass can be used. The structure is represented by the general formula below,

NaOnSiO ₂ xH ₂ O

Where n is 1-4. Specific examples thereof include sodium metasilicate, sodium orthosilicate, No. 1, No. 2 and No. 3 water glass. These shapes may be used by dissolving flakes, powders, and the like in water, or those sold as aqueous solutions.

In addition, the anionic particulate inorganic material element may be water insoluble, and may be charged as anionic in water, and various kinds can be used. Specifically, for example, oxides such as silicon dioxide, aluminum oxide, antimony oxide, titanium oxide and montmorillonite, bentonite, kaolin, activated clay, silica, alumina silicates such as diatomaceous earth, clay minerals such as magnesia silicates such as talc, or calcium carbonate Carbonate, such as these, etc. are mentioned.

When the particle size is too large, the compounding effect is low, and the particle size is usually 100 µm or less, preferably 50 µm or less, and more preferably 10 µm or less.

The co-addition ratio of Hoffman's degraded PAM with anionic inorganic material is by weight, 1-500%, preferably 2-400%, more preferably 3-300% relative to Hoffman's degraded PAM. If the ratio is too small, no combined effect is observed, while if too large, the Hoffman decomposition PAM property is impaired. The Hoffman decomposition rate at that time is not particularly limited, but is usually 5-60 mol%, preferably 10-50 mol%.

Specifically, a method of using an anionic inorganic material in combination is used, but the Hoffman decomposed PAM used in the present invention can be used as it is by reacting at a high temperature and a short time, and the reaction solution at that time is strongly alkaline. It can also be used together. Specifically, in (i) Hoffman decomposition reaction, the solution is dissolved in advance in caustic soda, hypochlorite oxygen, or a mixture thereof, and then Hoffman decomposition reaction is performed using this, or (ii) reaction after Hoffman decomposition reaction. It adds in a liquid, or (iii) adds individually.

In the present invention, the addition rate of the Hoffman decomposed PAM and the anionic inorganic substance to the pulp is usually in the range of 0.005-5.0%, preferably 0.01-2.0% per pulp dry weight. In addition, the ratio of Hoffman-decomposed PAM and anionic inorganic substance at that time changes with papermaking conditions. Specifically, for example, when increasing the papermaking speed and increasing the papermaking speed, the ratio of the anionic inorganic substance is kept low, while the purpose of producing a homogeneous paper by preparing the paper quality composition is reversed. The addition ratio may be increased.

In the method of this invention, when an aluminum sulfate and water-soluble anionic resin are used together, the effect may increase further. The water-soluble anionic resin used at this time is water-soluble resin containing anionic substituents, such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group, or their salts, For example, anionic acrylamide type resin, anionic polyvinyl alcohol type resin, and carboxy Methyl cellulose, carboxymethylated starch, sodium arginate, etc. are mentioned. The addition step is not particularly limited and may be added to the pulp slurry before or after the addition of Hoffman decomposed PAM and sodium silicate to the pulp slurry. Moreover, it is also possible to mix with Hoffman-decomposed PAM and sodium silicate, or to mix them with the liquid mixture.

The addition step can be anywhere before the wet sheet is formed. The drug is preferably diluted and mixed with the pulp slurry and added at a place close to the papermaking wire, for example, at a machine chest, mixing box, seed box, white wort pit, screen outlet, or the like. The paper machine used for papermaking may be any one of a long paper machine and a long paper machine. After adding the present papermaking additive to the pulp slurry having a concentration of 0.5-5.0%, pH 4.0-9.0, and temperature of 20-70 ° C, a wet sheet is formed in the wire section, and then water is squeezed in the press section. The nip pressure in the press section is in the range of 20-400 kg / cm. The wetland which passed the press part moves to a dry part, and drying by steam is performed. At this time, the vapor pressure is about 2-15kg / cm ² , it is dried by a drum of 80-200 ℃. Subsequently, processing by chemicals for the purpose of improving printability, surface strength, water resistance and water repellency in size presses and calendars is also possible.

In addition, the papermaking additive in this invention is a water-soluble mixed liquid which uses Hoffman-decomposed PAM and an anionic inorganic substance as an active ingredient, and an active ingredient concentration is 0.001-50% of range. The mixing ratio of the anionic inorganic material to the Hoffman decomposed PAM is 1-500% by weight, preferably 2-400%, more preferably 3-300%. If the mixing ratio is too small, no mixing effect is observed, while if too large, the properties of the Hoffman decomposed PAM are impaired. Hoffman decomposition rate at that time is not particularly limited, but is usually 5-60 mol%, preferably 10-50 mol%. As the mixing method of Hoffman decomposition PAM and an anionic inorganic substance, (i) When Hoffman decomposition reaction is carried out, it is previously added and dissolved in caustic soda, sodium hypochlorite or a mixture thereof, and it is used for Hoffman decomposition reaction, (Ii) mixing with the reaction solution after the Hoffmann decomposition reaction; The solution after the Hoffmann decomposition reaction is usually in the range of pH 12-13, but may be lowered with an inorganic acid or an organic acid before mixing with the anionic inorganic material, or lowered after mixing with the anionic inorganic material. The papermaking additive in is in the range of pH 2-14.

In this invention, the cationic monomer represented by general formula (I) is the (meth) acrylic acid ester derivative represented by dimethylaminoethyl (meth) acrylate, diethyl amino ethyl (meth) acrylate, and dimethylaminopropyl ( (Meth) acrylamide derivative etc. which correspond to meta) acrylamide or diethylaminopropyl (meth) acrylamide are illustrated. Salts of organic to inorganic acids mean salts of inorganic acids such as sulfuric acid, hydrochloric acid, phosphoric acid, or acetic acid, ureic acid, and the like. The quaternary ammonium salts obtained by the reaction between the general formula (I) and the quaternizing agent include a vinyl monomer having a tertiary amino group, methyl chloride, methyl bromide, methyl iodide, dimethyl sulfate, and epichlorohydrin. Vinyl monomer etc. which have quaternary ammonium salt obtained by reaction with quaternization agents, such as benzyl chloride, can be illustrated. In the present invention, a vinyl monomer having a tertiary amino group or salts of organic or inorganic acids thereof may be mixed with quaternary ammonium salts obtained by reaction with a quaternizing agent. These mixing ratios are not specific ratios.

The amount of these cationic monomers is 0.5-70 mol% normally, Preferably it is 2-50 mol%.

Α, β-unsaturated carboxylic acids or salts thereof of the present invention, such as alkali metal salts or ammonium salts, are vinyl monomers having anionic properties, such as maleic acid, fumaric acid, itaconic acid, (meth) acrylic acid, Unsaturated carboxylic acids, such as crotonic acid or citraconic acid, or alkali metal salts, such as sodium salt or potassium salt, ammonium salt, etc. can be illustrated. The amount of monomers used thereof is 0.5-20 mol%, preferably 2-20 mol%.

The monomer represented by general formula (II) of this invention contains acrylamide and methacrylamide, and if it is marketed in the state of powder or aqueous solution, and is industrially used, it is enough. Their amount of monomer used is 10-90 mol%.

In this invention, a crosslinkable monomer (d) can also be used as a 4th component besides (a)-(c). As a crosslinkable monomer, the monomer which has at least 2 or more double bond in a molecule | numerator, and an N-alkoxy methyl (meth) acrylamide derivative are mentioned. Specific examples of the former include methylenebisacrylamide, triacylformal, diallylacrylamide, triacylformal, diacryloimide, ethylene glycol acrylate, ethylene glycol dimethacrylate, and propylene glycol di. Acrylate, 1, 3-butylene glycol dimethacrylate, 1, 4-butylene glycol methacrylate, glycerol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, divinylbenzene , Diallyl phthalate, etc. can be used. N-alkoxymethyl (meth) acrylamide derivative includes N-hydroxymethyl (meth) acrylamide, for example, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, Nn-butoxymethyl (meth) acrylamide, N-tert-butoxymethyl (meth) acrylamide, etc. can be used. The amount of these crosslinking agents used depends on the type of crosslinkable monomer and can not be said uniformly, but is usually 0.0001-20 mol%, preferably 0.001-10 mol%. If it is less than 0.0001mol%, there is a problem that the intelligence effect cannot be sufficiently expressed, and if it exceeds 20mol%, there is a problem that gelation occurs.

Moreover, as a method of obtaining the cationic polyacrylamide (B) of this invention, the conventionally well-known method used for superposition | polymerization of this kind of water-soluble vinyl monomer is used.

For example, radical polymerization is preferable as the polymerization method. The monomer concentration is 2-30% by weight, preferably 5-30% by weight. The polymerization initiator is not particularly limited as long as it is water-soluble, and is usually used after being dissolved in an aqueous monomer solution. Specifically, hydrogen peroxide, peroxides such as benzoyl peroxide, sodium persulfate, potassium persulfate, persulfates such as ammonium persulfate, sodium bromide, bromates such as potassium bromide, sodium perborate, potassium perborate, perborate Perborate such as ammonium acid, sodium percarbonate, potassium percarbonate, percarbonate such as ammonium percarbonate, sodium perphosphate, potassium perphosphate, superphosphate such as ammonium perphosphate, and tert-butylperoxide. In this case, although it can be used alone, it can also be used as a redox-type polymer in combination with a reducing agent. Examples of the reducing agent include salts of metals with low ionization deficiencies such as sulfite, hydrogen sulfite, iron, copper, and cobalt, organic amines such as N, N, N ', N'-tetramethyl ethylene diamine, or aldose, Reducing sugars such as ketose; and the like.

Moreover, as an azo compound, 2, 2'- azobis-4- amidino propane hydrochloride, 2, 2'- azobis-2, 4 dimethyl valelonitrile, 4, 4'- azobis-4- cyano valer Acids and salts thereof can be used. Moreover, it is also possible to use 2 or more types of said polymerization initiators together. The polymerization temperature is somewhat lower at about 30-90 ° C. for homopolymerization initiators and is usually lower at 5-50 ° C. for redox-based polymerization initiators. Moreover, it is not necessary to maintain the same temperature during superposition | polymerization, and it may change suitably with progress of superposition | polymerization, and generally heats up by the heat of superposition | polymerization which generate | occur | produces with advancing of superposition | polymerization. The atmosphere in the polymerization reactor at that time is not particularly limited, but in order to speed up the polymerization, it is better to substitute an inert gas such as nitrogen gas. The polymerization time is not particularly limited but is usually 1-20 hours.

The method of the present invention is used in the process of papermaking pulp, and has a great effect in improving the fidelity for water drainage during papermaking, and strengthening the paper to enhance the mechanical strength of paper.

In the present invention, the use ratio of Hoffman decomposed PAM and cationic polyacrylamide (B) is arbitrary depending on the pulp material or white water, but considering the mixing effect is 95: 5-5: 95, preferably The following is 80: 20-20: 80. In addition, the method of adding cationic polyacrylamide or the like adds Hoffman decomposed PAM and cationic polyacrylamide (B) alone to the pulp slurry. Alternatively, there is a method of adding Huffman decomposed PAM and a cationic polyacrylamide (B) to the pulp slurry, and any method may be used.

Also in the combination of Hoffman-decomposed PAM and cationic polyacrylamide (B), when an aluminum sulfate and water-soluble anionic resin are used together, the effect may increase further. The water-soluble anionic resin used at this time is water-soluble resin containing anionic substituents, such as a carboxyl group, a sulfonic acid group, and a phosphoric acid group, or their salts, For example, anionic acrylamide type resin, anionic polyvinyl alcohol type resin, and carboxy Methyl cellulose, carboxymethylated starch, sodium arginate, etc. are mentioned. The addition step is not particularly limited, and Huffman decomposed PAM and cationic polyacrylamide (B) can be added to the pulp slurry before and after or simultaneously with the pulp slurry. Moreover, it is also possible to mix with Hoffman-decomposed PAM and cationic polyacrylamide (B), or to mix with Hoffman-decomposed PAM and cationic polyacrylamide (B).

The addition step may be any place before the wet sheet is formed, and it is preferable that the medicine is sufficiently mixed with the pulp slurry and added at a place close to the papermaking wire. Specifically, the machine chest, mixing box, seed box, white warm feet , Screen exit and so on. As the paper machine used for papermaking, any of a long paper machine and a long paper machine can be used. After adding the present papermaking additive to the pulp slurry having a concentration of 0.5-5.0%, pH 4.0-9.0, and temperature of 20-70 ° C, a wet sheet is formed in the wire part, and then water is squeezed in the press part. Nip front at the press section is in the range of 20-400 kg / cm. The wetland which has passed through the press part moves to the dry part and is dried by steam. At this time, the vapor pressure of 2-15kg / cm ² is used, it is dried by a drum of 80-200 ℃. Subsequently, processing by chemicals for the purpose of improving printability, surface strength, water resistance and water repellency in size presses and calendars is also possible.

Moreover, the papermaking additive in this invention is a water-soluble mixed liquid which uses Hoffman-decomposed PAM and cationic polyacrylamide (B) as an active ingredient, and an active ingredient concentration is in the range of 0.001-50%. The mixing ratio of cationic polyacrylamide (B) to Hoffman decomposed PAM is 95: 5-5: 95 by weight, preferably 80: 20-20: 80. If the mixing ratio is too small, no mixing effect is observed, while if too large, the property of Hoffman decomposed PAM is impaired. The Hoffman decomposition rate at that time is not particularly limited, but is usually 5-60 mol%, preferably 10-50 mol%. As a method of mixing Hoffman decomposition PAM with cationic polyacrylamide (B), the solution after Hoffman decomposition reaction is usually in the range of pH 12-13, but before mixing with cationic polyacrylamide (B) with an inorganic acid or an organic acid, It is also possible to lower the pH, and to reduce the pH after mixing with the cationic polyacrylamide (B), and the papermaking additive in the present invention is in the range of pH 2-14.

By producing in the above manner, it is possible to improve the freeness without causing a decrease in the strength of strength, specifically, the bursting strength, the Z-axis strength, the compressive strength, or the like. Therefore, if the method of the present invention is applied, it is very effective to use paper having a high ratio of used paper to raw materials, such as corrugated paper or newspaper, and it is possible to manufacture paper having high strength. In addition, the present invention is not limited to corrugated paper or newspaper, and when the present invention is applied when fidelity is required in a papermaking process, it is possible to produce a paper having excellent strength strength with good productivity.

Best Mode for Carrying Out the Invention

Next, although an Example demonstrates this invention, this invention is not necessarily limited to a following example. Also, the percentages are all% by weight unless otherwise indicated.

[Production Example 1]

24.0 g of an aqueous 10% by weight polyacrylamide solution (Brookfield viscosity at 25 ° C: 3.400 cps) was taken in a 500 ml beaker, diluted with 36.0 g of distilled water, and heated to 80 ° C while stirring the solution. 14.8 g of a mixed solution of NaOH (sodium hypochlorite concentration: 10 mol / kg, NaOH concentration: 2.0 mol / kg) was added, and after 15 seconds, 225.2 g of cold water at 5 ° C. was added to stop the reaction. A system polymer was obtained (Hoffman PAM (A)). A portion of the reaction product was taken up in an aqueous solution of pH 2 and subjected to colloid titration with 1 / 400N-polyvinylsulfonic acid potassium aqueous solution using toluidine blue as an indicator. The cationic value was 4.4 meq / g. In the test below, Hoffman PAM (A) was used immediately after preparation.

[Production Example 2]

24.0 g of 12.5 wt% aqueous polyacrylamide solution (Brookfield viscosity at 25 ° C: 12.400 cps) was taken in a 500 ml beaker, diluted with 36.0 g of distilled water, and the solution was stirred at 20 ° C. with sodium hypochlorite. 14.8 g of a mixed solution of NaOH and sodium hypochlorite (1.0 mol / kg, NaOH concentration: 2.0 mol / kg) was added. After 2 hours, 225.2 g of 0.001% sodium sulfite aqueous solution was added to stop the reaction. An amide polymer was obtained (hereinafter Hoffman PAM (B)). A part of the reaction product was taken in an aqueous solution of pH 2, and colloid titration was performed with an aqueous 1 / 400N-polyvinylsulfonic acid solution using toluidine blue as an indicator, and the cationic value was 4.4 meq / g.

Example 1

Even if the old cardboard is hardened (used by Canadian Standard Priness), it is treated with a commercially available rosin emulsion sizing agent on a dry weight of 0.15% on a pulp slurry of 1% pulp slurry. Added and stirred for 2 minutes. Next, aluminum sulfate was added by 1.0% by dry weight and stirred for 1 minute. PH of the pulp slurry at this time was 5.1. Subsequently, 0.30% of No. 3 water glass was added on a dry weight basis, and 0.60% of Hoffman PAM (A) obtained in Preparation Example 1 was added after stirring for 1 minute. After continuing stirring for 1 minute, a part of the obtained pulp slurry was taken, CSF was measured according to JIS-P-8121, and the remainder was paper-cut by the TAPPI square sheet machine. Subsequently, the resultant was dried with a blower at 110 ° C. for 2 hours to obtain a herbaceous paper having a weight of 150 ± 3 g / m ² . This sheet was measured using "uncompressed strength" in accordance with JIS-P-8126, and "Z-axis strength" using "non-rupture strength" and the Kudani Nigyo Kogyo internal bond tester in accordance with JIS-P-8112. It was. The results are shown in Table 1.

Example 2

The papermaking test was carried out in the same manner as in Example 1, except that 0.60% of No. 3 water glass was added on a dry weight basis.

The results are shown in Table 1.

Example 3

The papermaking test was carried out in the same manner as in Example 1 except that 0.90% of No. 3 water glass was added based on the dry weight.

The results are shown in Table 1.

Example 4

The papermaking test was conducted in the same manner as in Example 1 except that 1.50% of No. 3 water glass was added based on the dry weight.

The results are shown in Table 1.

Comparative Example 1

The papermaking test was conducted in the same manner as in Example 1 except that No. 3 water glass was added in an amount of 0.003% based on the dry weight.

The results are shown in Table 1.

Comparative Example 2

The papermaking test was conducted in the same manner as in Example 1, except that 5.00% of water No. 3 was added on a dry weight basis.

The results are shown in Table 1.

[Comparative Examples 3 and 4]

The papermaking test was carried out in the same manner as in Comparative Examples 1 and 2 except that Hoffman PAM (A) used in Comparative Examples 1 and 2 was replaced with Hoffman PAM (B).

The results are shown in Table 1.

Example 5

0.5% of aluminum sulfate was added to a pulp slurry having a concentration of 543 ml of 1.0% pulp treated with high degree of corrugated cardboard (write Canadian Standard Priness, hereinafter referred to as C.S.F) and stirred for another 1 minute. PH of the pulp slurry at this time was 5.8.

Next, 0.25% of colloidal silica (Snotex 40, 10-20 mm particle diameter, manufactured by Nissan Kagaku Kogyo Co., Ltd.) was added, and stirred for 30 seconds, and Hoffman PAM (A) obtained in Preparation Example 1. Added. After continuing stirring for 30 second, a part of the obtained pulp slurry was taken, CSF was measured according to JIS-P-8121, and the remainder was paper-cut by TAPPI square sheet machine. Subsequently, the resultant was dried for 2 hours using a blower at 110 ° C. to obtain a paper sheet having a weight of 150 ± 3 g / m ² . This sheet was measured for the non-compressive strength according to JIS-P-8126, and the Z-axis strength using the non-rupture strength and the Kumagayariki internal bond tester according to JIS-P-8112.

The results are shown in Table 2.

Example 6

The papermaking test was conducted in the same manner as in Example 5 except that 0.50% of the colloidal silica was added on a dry weight basis.

The results are shown in Table 2.

Example 7

The papermaking test was conducted in the same manner as in Example 5 except that 1.00% of the colloidal silica was added on a dry weight basis.

The results are shown in Table 2.

[Comparative Example 5]

The papermaking test was conducted in the same manner as in Example 5 except that 0.001% of the colloidal silica was added on a dry weight basis.

The results are shown in Table 2.

Comparative Example 6

The papermaking test was conducted in the same manner as in Example 5 except that 10.0% of the colloidal silica was added on a dry weight basis.

The results are shown in Table 2.

[Manufacture example 3]

40%, 675 g (94 mol%) acrylamide, 23.1 g (4 mol%) dimethylaminoethyl methacrylate, 5.8 g (2 mol%) acrylic acid, in a four-necked flask equipped with a stirrer, a reflux cooling tube, a thermometer and a nitrogen gas introduction tube. 62.3 mg (0.01 mol%) of bismethylene acrylamide and 1.004 g of water were added thereto, followed by adjusting to pH 4.5 with 10% aqueous sulfuric acid solution. After this, while blowing nitrogen gas, the internal temperature was raised to 40 ℃. While stirring, 10% aqueous ammonium persulfate solution and aqueous sodium hydrogen sulfite solution were added to initiate polymerization. Thereafter, the mixture was kept at 85 ° C and water was added 3 hours after the start of the polymerization to complete the polymerization reaction. Thus, a stable acrylamide-based polymer aqueous solution having a non-volatile content of 15.3% and a Brookfield viscosity of 6,800 cps at 25 ° C and a pH of 4.3 was obtained. .

[Production Example 4]

30 g of 10 wt% aqueous polyacrylamide solution (Brookfield viscosity at 25 ° C .: 3400 cps) was taken in a 500 ml beaker, diluted with 30.0 g of distilled water, and the solution was heated to 80 ° C. with stirring, sodium hypochlorite and NaOH. 14.3 g of a mixed solution of sodium hypochlorite (1.0 mol / kg, NaOH concentration: 2.0 mol / kg) was added, and after 15 seconds, 225.7 g of cold water at 5 ° C. was added to stop the reaction. (Hoffman PAM (C)) was obtained. A part of the reaction product was taken in an aqueous solution of pH 2 and colloid titrated with an aqueous 1 / 400N-polyvinylsulfonic acid potassium solution using toluidine blue as an indicator, and the cationic value was 3.8 meq / g. In the test below, Hoffman PAM (C) was used immediately after preparation.

Example 8

A commercially available rosin emulsion sizing agent was added to 400 ml of 10% pulp slurry treated with high degree of corrugated paper (referred to as Canadian Standard Priness, hereinafter referred to as CSF), and stirred for 2 minutes by adding 0.15% to the pulp on a dry weight basis. . Next, aluminum sulfate was added by 1.0% by dry weight and stirred for 1 minute. PH of the pulp slurry at this time was 5.1. The acrylamide polymer obtained in Preparation Example 3 was added to 0.30% by dry weight. After stirring for 1 minute, Hoffman PAM (C) obtained in Preparation Example 4 was added by 0.10% by dry weight. After continuing stirring for 1 minute, a part of the obtained pulp slurry was taken, CSF was measured according to JIS-P-8121, and the remainder was paper-cut by TAPPI square sheet machine. Then, the resultant was dried for 2 hours using a blower dryer at 110 ° C. to obtain a paper sheet having a weight of 125 ± 3 g / m ² . This sheet was measured for specific compressive strength in accordance with JIS-P-8112, and Z-axis strength using non-rupture strength and an internal bond tester manufactured by Kumagi Riki Kogyo Co., Ltd. in accordance with JIS-P-8126. The results are shown in Table 3.

Example 9

The resin paper was prepared in the same manner as in Example 8 except that 0.20% of the polyacrylamide polymer obtained in Production Example 3 was added on a dry weight basis, and 0.20% of Hoffman PAM (C) obtained in Production Example 4 was added on a dry weight basis. Test was made.

The results are shown in Table 3.

Example 10

The resin sheet was prepared in the same manner as in Example 8 except that 0.10% of the polyacrylamide polymer obtained in Preparation Example 3 was added on a dry weight basis, and 0.30% of Hoffman PAM (C) obtained in Preparation Example 4 was added on a dry weight basis. Test was made.

The results are shown in Table 3.

Comparative Example 7

The same test as in Example 8 was conducted except that 0.40% of the acrylamide polymer obtained in Preparation Example 3 was added and Hoffman PAM (C) obtained in Preparation Example 4 was not added.

The results are shown in Table 3.

Comparative Example 8

The same test as in Example 8 was carried out except that Hoffman PAM (C) obtained in Production Example 4 was added 0.40% and acrylamide-based polymer obtained in Production Example 3 was not added.

The results are shown in Table 3.

As shown in Tables 1 and 2, the papers produced under the conditions of the present invention showed a change in the freeness by the addition of the anionic inorganic material, but the strength of the paper tended to be improved by the addition of the anionic inorganic material. When an appropriate amount of the anionic inorganic material is present, the cohesion force of Hoffman PAM is moderately lowered, and thus, the cohesive force is shifted in the direction to prepare the paper material, and thus excellent in intellective performance such as non-rupture strength, incompressive strength, and Z-axis strength. It is assumed that. This effect is remarkable when the Hoffman decomposition reaction is performed for a short time in the temperature range of 50 ° C-110 ° C. The strength of the PAM that Hoffman decomposition reaction is performed at high temperature and in a short time by using an anionic inorganic material for its functional mechanism Clearly, the effect can be enhanced.

Therefore, even if sacrificing some degree of freeness, if the present invention is applied to produce a paper having excellent strength by adjusting the paper quality, it can bring a great effect.

In addition, as shown in Table 3, the paper made under the conditions within the claims of the present invention was prepared in Preparation Example 3 or 4 while maintaining the level of freeness when the acrylamide polymer obtained in Preparation Example 4 was used alone. Compared with the case where the obtained acrylamide polymer is used alone, excellent effects can be obtained in performances such as non-rupture strength, non-compressive strength and Z-axis strength.

TABLE 1

TABLE 2

TABLE 3

Industrial availability

Paper made by the method of the present invention is excellent in intellective performance, such as non-rupture strength, incompressive strength, Z-axis strength.

In the case of the addition of the anionic inorganic substance, the paper quality is adjusted to produce paper having excellent strength, even if the degree of freeness is sacrificed to some extent.

When the cationic polyacrylamide is added, acrylamide-based polymers are used alone without being affected by deterioration of quality as expected in the hydrophobicity, while maintaining the level of freeness when acrylamide-based polymers are used alone. It is superior in intellect performance compared to the case.

Claims (4)

Wet pulp sheet is obtained by adding together the cationic acrylamide polymer and anionic inorganic material obtained by reacting acrylamide polymer and hypohalogenate under alkaline conditions for a short time in the temperature range of 50-110 ° C. And a dehydration treatment by a press, followed by drying with a dryer. The acrylamide-based polymer and the hypohalogen acid salt according to claim 1, wherein the acrylamide-based polymer and the hypohalogenate can be represented by the following formula in the range of reaction temperature T (° C): 50 ° C≤T≤110 ° C. Cationic acrylamide-based polymer and anionic inorganic material obtained by the reaction within the same short reaction time t (sec) are added to the pulp slurry, and a wet pulp sheet is formed. The press is dehydrated and dried in a dryer. Paper making method, characterized in that for doing. A papermaking additive composed of a cationic acrylamide polymer and an anionic inorganic material obtained by reacting an acrylamide polymer and a hypohalogenate under alkaline conditions in a temperature range of 50-110 ° C. for a short time. The acrylamide-based polymer and the hypohalogen acid salt according to claim 3, wherein the acrylamide-based polymer and the hypohalogenate can be represented by the following formula in the range of reaction temperature T (° C): 50 ° C≤T≤110 ° C. A papermaking additive comprising a cationic acrylamide-based polymer and an anionic inorganic material obtained by reacting within the same short reaction time t (sec).