JPH0457994A - Additive for paper-making process - Google Patents

Abstract

PURPOSE:To obtain a paper-making additive suitable as an additive for pulp slurry to improve the paper strength by reacting a specific cationic copolymer with a hypohalite under alkaline condition. CONSTITUTION:The objective additive can be produced by copolymerizing (A) 0.1-20mol% of a diallylamine derivative monomer of formula I (R1 and R2 are H or CH3; R3 and R4 are H or 1-6C alkyl; X is anion of inorganic or organic acid) and (B) 80-99.9mol% of an acrylamide monomer of formula II (R5 is H or CH3) and reacting the resultant cationic copolymer with (C) a hypohalite at 50-110 deg.C under alkaline condition in a short time.

Description

[Detailed description of the invention] [Industrial application field] Book! ! The present invention relates to additives for papermaking. More specifically, a cationic acrylamide polymer obtained by copolymerizing a diallylamine derivative monomer and an acrylamide monomer and subjecting the copolymer to a Hofmann decomposition reaction at high temperature in a short time is used as a papermaking additive, This product is characterized by being less affected by fluctuations in PL during paper making, and exhibiting stable effects against dissolved components present in the pulp slurry, such as msa salts such as sodium sulfate and calcium sulfate. The present invention relates to such an additive for paper, and a method for increasing paper strength and a method for improving drainage using the additive for paper manufacturing.

[Prior art and its problems]

Conventionally, cationic acrylamide-based polymers (hereinafter acrylamide-based polymers are simply referred to as polyacrylamide) include Hoffmann-decomposed polyacrylamide, Mannich-modified polyacrylamide, and copolymers of cationic monomers and acrylamide. It is used for various purposes such as a reinforcing agent, a polymer N-curing agent, and a drainage improver, or its use is being considered.

Among the above, although Hofmann-decomposed polyacrylamide has excellent characteristics not found in Mannich-modified polyacrylamide and copolymers with cationic monomers, it is said that its cationic properties disappear over time in an aqueous solution. Due to the problem of deterioration over time, it has not been widely put into practical use.

Conventionally, various studies have been made to improve this point. One of these attempts is to perform the Hofmann decomposition reaction of polyacrylamide at a low temperature to suppress side reactions and thereby suppress deterioration over time. That is, to Polymer Paper Collection 339, No. 6, 309-316, 19
In 1976, it was pointed out that in the Hofmann decomposition reaction of polyacrylamide C, conversion to amino groups easily occurs even at low temperatures due to the reaction promoting effect of adjacent groups, and side reactions (hydrolysis,
Generally 2 to suppress lactam ring formation*, depolymerization, etc.
It is disclosed that it is desirable to carry out the reaction at a temperature of 5° C. or less in order to obtain a high performance aminated PAM.

Similarly, regarding the advantages of conducting the Hofmann decomposition reaction of polyacrylamide at low temperatures, JP-A No. 61-200103
, JP-A-58-152004, JP-A-58-10820
6, JP-A-57-165404, JP-A-55-6556
, Japanese Patent Publication No. 52-152493. Japanese Patent Publication No. 51-12218
It is also listed in 8th grade. However, simply carrying out the Hofmann decomposition reaction at a low temperature does not improve the change over time to a level that is suitable for practical use.

Another method is to coexist a hydroxyl-substituted compound with a cationic group such as a quaternary ammonium salt, or an N,N-dialkyl-substituted diamine, guanidine, polyamine, etc. during the Hofmann decomposition reaction. fJ (Special R.Sho 62-59602
, Toku Ill 1146l-1208 (17, Tokukai II!
157-192408, JP-A-58-144295, JP-A-54-145790, JP-A-53-109594, etc. However, the reality is that even with such methods, satisfactory results have not been obtained.

[Problem that the invention seeks to solve]

In the present invention, dialkyldiallylammonium chloride is introduced into the main chain in order to be effective in a wide papermaking pH range and to provide resistance to inorganic salts present in pulp slurry, and the Hofmann decomposition reaction is carried out at high temperature. ,
The purpose of the present invention is to provide a papermaking additive having stable performance and high paper strength by performing the process in a short period of time. Furthermore, the present invention provides a method for increasing paper strength and a method for improving drainage by performing a Hofmann decomposition reaction at a high temperature and in a short time and adding it to paper.

[Means to solve the problem]

In view of the above points, the present inventors have conducted a detailed study on the Hofmann decomposition reaction of polyacrylamide.

We have discovered that by extremely shortening the reaction time in the single-temperature reaction of Hoffmann decomposition, which has not been considered in the past, it is possible to produce cationic polyacrylamide having properties equivalent to or superior to those of Hoffmann decomposition polyacrylamide produced by low-temperature reaction. This led to the present invention.

That is, the present invention basically involves mixing an acrylamide polymer and a hypohalite in an alkaline region at a concentration of 50 to 50%.
This is a cationic polyacrylamide obtained by performing a reaction in a short period of time in a temperature range of 110"C. This product has low dependence on l)H fluctuations during paper making, and is present in pulp slurry. It is characterized in that it has little effect on inorganic salts.It is characterized in that it is used as an additive for paper manufacturing.It is also characterized in that it is added immediately after production to strengthen paper strength and improve drainage. The present invention enables a completely new production system for cationic polyacrylamide that is different from the conventional ones, and by utilizing this production system, it is possible to avoid the problem of deterioration over time of Hoffmann decomposed polyacrylamide, and it can be widely used in paper manufacturing. This made it possible to develop its application as an additive for industrial use.

The present invention will be explained in detail below.

The diallylamine derivative monomer used in the present invention is -
Ship bottom (1) In formula C, R1 and R2 represent hydrogen or a methyl group, and R-
Each R represents hydrogen or an alkyl group having 1-6 carbon atoms, and X- represents an anion of an inorganic acid or an organic acid. Specifically, diallylamine,
Inorganic or organic acid salts of secondary amines such as dimethallylamine, diallylmethylamine, diallylethylamine,
Examples include inorganic or miscellaneous organic acid salts of tertiary amines such as diallylbutylamine, diallyldimethylammonium chloride, diallyldimethylammonium bromide, diallyldiethylammonium chloride, diallyldibutylammonium chloride, diallylmethylethylammonium chloride, and the like.

The acrylamide monomer copolymerized with formula (1) is
-Bottom (n) refers to a monomer represented by CH=C(Rs)-CON H2(II) (in the formula, R5 represents hydrogen or a methyl group), specifically, acrylamide and methacrylamide. I can do it.

In the present invention, the diallylamine derivative monomer represented by formula (I) and the acrylamide monomer represented by formula (II) are copolymerized, and one or more monomers copolymerizable with acrylamide (or methacrylamide) are also added. It is also possible to copolymerize with saturated monomers.

Examples of copolymerizable monomers include hydrophilic monomers, ionic monomers, and lipophilic monomers, and one or more of these monomers can be used. Specifically, as a hydrophilic monomer, for example, diacetone acrylamide, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-ethylmethacrylamide, N-ethylacrylamide, N,N-diethylacrylamide, N -propylacrylamide, N-acryloylpyrrolidine, N-acryloylpiperidine, N-acryloylmorpholine,
Hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, various methoxypolyethylene glycol (meth)acrylates, N-vinyl-2
- Examples include pyrrolidone.

Examples of ionic monomers include acrylic acid, methacrylic acid, vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, and 2-acrylamide-2 - Acids such as methylpropanesulfonic acid and their salts, N.

Amines and salts thereof such as N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, N,N-dimethylahanoethyl acrylate, N,N-dimethylaminopropylmethacrylamide, N,N-dimethylaminepropylacrylamide, etc. etc. can be given.

In addition, examples of the lipophilic monomer include acrylonitrile, N,N-di-n-propylacrylamide, N-n-
Butylacrylamide, N-n-hexylacrylamide, N-n-hexylmethacrylamide, N-n-octylacrylamide, N-n-octylmethacrylamide, N-tert-octylacrylamide, N-dodecyl acrylamide, N-n- N-alkyl (meth)acrylamide derivatives such as dodecylmethacrylamide,
N,N-diglycidyl acrylamide, N,N-diglycidyl methacrylamide, N-(4-glycidoxybutyl)acrylamide, N-(4-glycidoxybutyl)
Methacrylamide, N-(5-glycidoxypentyl)acrylamide, N
-N such as (6-gelicidoxyhexyl)acrylamide
-(ω-Glycidoxyalkyl) (meth)acrylamide derivative, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)
Acrylate, glycidyl (meth)acrylate, etc. (
meth)acrylate derivatives, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, vinylidene chloride, olefins such as ethylene, propylene, butene,
Examples include styrene, divinylbenzene, α-methylstyrene, butadiene, and isoprene. The amount of unsaturated monomers used for copolymerization varies depending on the type of unsaturated monomers and their combination, and is generally in the range of 0 to 50% by weight2.

Furthermore, both natural and synthetic water-soluble polymers can be used for craft copolymerization of the above-mentioned monomers. Starch and oxidized starch derived from various natural sources,
Modified products such as carboxyl starch, dialdehyde starch, cationized starch, cellulose derivatives such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, alginic acid, agar, pectin, carrageenan, dextran, pullulan, konjac, 7-rabiya gum, casein, gelatin, etc. can be given. Examples of synthetic systems include polyvinyl alcohol, polyvinyl ether, polyvinylpyrrolidone, polyethyleneimine, polyethyleneimine, polyethylene glycol, polypropylene glycol, polymaleic acid copolymer, polyacrylic acid, polyacrylamide, and the like.

The amount of the above-mentioned monomer added to the above-mentioned water-soluble polymer is in the range of 0.1 to 10.0 times based on the water-soluble polymer.

Next, the above-mentioned monomers are polymerized to produce cationic polyacryl 7mide. Radical polymerization is preferable as the polymerization method, and water, alcohol,
Although polar solvents such as dimethylformamide are applicable, aqueous solution polymerization is preferred since the Hofmann decomposition reaction is carried out in an aqueous solution.

The monomer concentration at that time is 2 to 30% by weight, preferably 5 to 3% by weight.
The 0% by weight 1 polymerization initiator is not particularly limited as long as it is water-soluble, and it is usually used after being dissolved in an aqueous monomer solution. Specifically, examples of peroxides include ammonium persulfate, potassium persulfate, aqueous peroxide, and tert-butyl peroxide. In this case, it can be used alone, but it can also be used as a redox polymerization agent in combination with a reducing agent. Examples of reducing agents include sulfites, hydrogen sulfites, salts of lower ionization such as iron, sea bream, and cobalt, organic amines such as N, N, N', N'-tetramethylethylenediamine, and aldoses and ketoses. Examples include reducing sugars such as

In addition, as an azo compound, 2.2°-azobis-2-
Amidinopropane hydrochloride, 2,2°-7zobisu2.4
-dimethylvaleronitrile, 4,4'-azobis-4-
Ciatsuvaleic acid and its salts, etc. can be used. Furthermore, it is also possible to use two or more of the above-mentioned polymerization initiators in combination. In addition, when graft polymerizing a water-soluble polymer, it is also possible to use transition metal ions such as ceric ions and ferric ions in addition to the above-mentioned polymerization initiators. It may be used in combination with a polymerization initiator. The amount of initiator added is 0.0 relative to the monomer.
It is 1 to 10% by weight, preferably 0.02 to 8% by weight. In the case of a redox system, the amount of reducing agent added to the initiator is 0.1 to 200%, preferably 0.2 to 150%, on a molar basis.

In the case of a single polymerization initiator, the polymerization initiation temperature is lower, approximately 30 to 90°C, and in the case of a redox polymerization initiator, it is lower, approximately 5 to 50°C. Further, it is not necessary to maintain the temperature at a temperature during the polymerization, and it may be changed as appropriate as the polymerization progresses, and the temperature is generally raised by the polymerization heat generated as the polymerization progresses. The atmosphere inside the polymerization vessel at that time is not particularly limited, but in order to speed up the polymerization, it is better to replace the atmosphere with an inert gas such as hydrogen gas.The polymerization time is not particularly limited, but is approximately 1 ~20 hours. In this way, a copolymer of a diallylamine derivative having a cationic group on the main plate and an acrylamide monomer, and/or a copolymer obtained by copolymerizing this with various monomers, is produced as a cationic polyacrylamide. Become.

Next, the cationic polyacrylamide produced by such a method is subjected to a Hoffman decomposition reaction. At this time, when the cationic polyacrylamide used as a raw material is produced in an aqueous solution, it can be used for the reaction as it is or diluted if necessary. In addition, in the case of graft copolymers, non-grafted polyacrylamide is also produced as a by-product.
Usually, it is used for the reaction as is without being separated.

The Hofmann decomposition reaction is carried out by allowing hypohalite to act on the amide group of polyacrylamide in the presence of an alkaline substance. Hypohalous acids include hypochlorous acid,
Examples include hypobromous acid and hypoiodic acid. 81: Examples of salts of chlorite include metal or alkaline earth metal salts of hypochlorous acid, specifically sodium hypochlorite, potassium hypochlorite, lithium hypochlorite, and hypochlorite. Examples include calcium chlorate, magnesium hypochlorite, barium hypochlorite, etc. Similarly, hypobromite and hypoiodite include alkali metal or alkaline earth metal salts of hypobromite and hypoiodite. It is also possible to generate hypohalite by blowing halogen gas into the alkaline solution.

On the other hand, alkaline substances include alkali metal hydroxides,
Examples include alkaline earth metal hydroxides and alkali metal carbonates. Among them, alkali metal hydroxides are preferred, and examples include sodium hydroxide, potassium hydroxide, lithium hydroxide, and the like.

The amount of the above-mentioned substance added to polyacrylamide is 0.05 to 2.0 per amide group for hypohalous acid.
mol, preferably 0.1 to 1.5 mol, and for alkaline substances 0.05 to 4.0 mol, preferably 0.1 to 3.0 mol, based on the amide group. The pH at that time is generally in the range of 11-14.

Under the above conditions, the concentration of cationic polyacrylamide is approximately 0.1 to 17.5% by weight, but as the reaction concentration increases, stirring becomes difficult and gelation tends to occur, so it is usually 0.1 to 17.5% by weight. It is preferably in the range of .1 to 10% by weight. Further, if the reaction concentration is less than 1.chi., there are problems such as a slow reaction rate, so it is more preferably 1 to 10% by weight.

On the other hand, the reaction temperature is in the range of 50 to 110°C, preferably in the range of 60 to 100°C.

In the present invention, the Hofmann decomposition reaction is then carried out within the above concentration range in a short period of time, but the reaction time may vary depending on the reaction temperature and the polymer concentration in the reaction solution. If the amount is about 1 to 10% by weight, within a few minutes at 50°C, within a few minutes at 65°C, 8
At 0°C, several tens of seconds or less is sufficient. Furthermore, the higher the polymer concentration, the shorter and cleaner the reaction time. The relationship between the reaction time and the reaction temperature is generally within the range between the following two relational expressions, and a suitable result can be obtained if the reaction is carried out within this range.

T: Reaction temperature ("C) 5 o ≦ T ≦ 110 The cationic polyacrylamide produced under the above conditions has a cation equivalent measured by colloid titration at PH2, which is approximately in the range of D to 10.0 eq/g. The cation equivalent can be controlled by the amount of hypohalite added.Also, since the reaction is carried out in an alkaline region, the amide group is hydrolyzed and a carboxyl group is produced as a by-product.The amount of the by-product is Indicated by anion equivalent measured by colloid titration at pH 10, approximately 0-10.0*eq/g
within the range of The amount of by-product can be controlled by the amount of alkaline substance added.

Next, after carrying out the reaction under the above-mentioned conditions, in the present invention, it is preferable to stop the reaction in order to suppress the progress of side reactions. However, if the reaction is used immediately after the reaction as described below, the reaction does not necessarily have to be stopped.

Methods for stopping the reaction include (1) adding a reducing agent;
Methods such as (2) cooling to a low temperature, and (3) lowering the pH of the solution by adding an acid can be used alone or in combination. (1) is a method in which remaining hypohalite and the like are deactivated by reaction with a reducing agent. Reducing agents used include sodium sulfite, sodium thiosulfate, ethyl malonate, thioglycerol, and triethylamine. The amount of reducing agent used is usually 0.00% relative to the hypohalous acid used in the reaction.
05 to 0.15 times the mole, preferably 0.01 to 0.10
It is twice the mole. Generally, when the Hofmann decomposition reaction is completed, unreacted compounds containing active chlorine such as hypohalite salts remain. If such a reaction solution is used as a paper strength agent, it may cause rust in the paper machine, so normally a reducing agent is used to deactivate the active chlorine. however,
The hypohalite reacts in a molar amount equal to or less than the number of moles of acrylamide units in the polymer, and if the reaction is carried out at a high temperature, almost no unreacted hypohalite remains at the end of the reaction. Therefore, if such conditions are adopted, it is also possible to use active chlorine as a paper strength agent without deactivating it using a reducing agent. (2) is a method of suppressing the reaction progress by cooling, which includes methods such as cooling using a heat exchanger and diluting with cold water. The temperature during cooling is usually 50°C or less, preferably 45''C or less, more preferably 40°C or less.

There is no limit to the temperature below, but temperatures above freezing are preferred. (
In step 3), the pH of the solution at the end of the reaction, which is usually alkaline at pH 12 to 13, is lowered using an acid to stop the Hofmann decomposition reaction and at the same time suppress the progress of the hydrolysis reaction. The pH at that time should just be neutral or lower, preferably in the range of pH 4 to 6. Examples of acids used for pH adjustment include mineral acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid, and organic acids such as formic acid, acetic acid, and citric acid.

The reaction termination method can be appropriately selected from among (1) to (3) depending on the reaction conditions, and these methods may be combined.

In the present invention, the reaction solution stopped by the above method can be used as it is as an aqueous solution of cationic polyacrylamide, or the aqueous solution can be poured into a solvent such as methanol that does not dissolve cationic polyacrylamide to precipitate the polymer. It can also be dried and made into a powder. Moreover, the cationic polyacrylamide aqueous solution obtained by the above method can be stored in a tank and used as needed. The temperature at which the aqueous solution is stored may be as low as not freezing, preferably 10 to 15°C. However, if it is to be used within a relatively short period of time, it can be stored at room temperature, and can be stored for about one month.

As mentioned above, the cationic polyacrylamide of the present invention can be produced in an extremely short time, so it can be used at any place where it is used (
On-site production, such as installing manufacturing equipment near the plant, becomes possible. This point is a major feature of the paper strength increasing method and drainage improving method of the present invention. At this time,
If the reaction is carried out under conditions in which the amount of hypohalite used is less than the amide group of polyacrylamide, it is possible to prevent free hypohalite ions from remaining in the solution. In this case, it can be added to pulp slurry or the like without stopping the reaction.

The cationic polyacrylamide produced according to the present invention can be applied to fields in which ordinary water-bathable cationic polymers are used, and among these, the main applications are in the field of chemicals and polymer flocculants used in paper making. etc. In the field of paper chemicals, cationic polymers are used in various areas of the paper manufacturing process, and the cationic polyacrylamide produced by the method of the present invention is used in the process of making paper valves. Its addition brings great effects, such as improving drainage to improve water drainage and increasing paper strength to increase the mechanical strength of paper. Furthermore, the cationic polyacrylamide of the present invention is particularly resistant to changes in pH 1 or ionic strength during papermaking, and is therefore effective as a papermaking chemical in a wide range of applications. These effects may be further enhanced when used in combination with a water-soluble anionic resin. The water-soluble anionic resin used at this time is a water-soluble resin containing anionic substituents such as carboxyl groups, sulfonic acid groups, phosphoric acid groups, or salts thereof, such as anionic acrylamide resins, Examples include anionic polyvinyl alcohol resin, carboxymethyl cellulose, carboxymethylated starch, and sodium alginate.

The method of using the cationic polyacrylamide of the present invention for the purpose of a drainage improver may be carried out according to a conventionally known method.However, the feature of the method of the present invention is that the cationic polyacrylamide and hypohalogen After reacting with the acid salt at high temperature and short time, it is added to the pulp slurry immediately. Here, "immediately" means that the aqueous solution after the reaction is taken out from inside the pipe, transported within the same pipe and added to the pulp slurry without being transferred to the outside. More specifically, the aqueous solution after the reaction may be directly added to the pulp slurry through a pipe, or a stock tank may be provided between the reactors and the aqueous solution may be temporarily retained there, and then the amount may be adjusted and added. 1m of reaction liquid in the pipe
The time may be within a range in which the aqueous solution after the reaction does not deteriorate; however, if it is too long, the device for retaining the liquid will become large and the features of the present invention will not be utilized. Therefore, in order to suitably carry out the present invention, it is preferable to add within 5 hours after the reaction, more preferably within 1 hour, and even more preferably within 10 minutes.

Further, at that time, it may be added after being diluted with water depending on the concentration of the cationic polyacrylamide after the reaction. The dilution is
It may vary depending on the type of valve, speed of paper making, etc.
The concentration of cationic polyacrylamide when added is approximately 0.1 to 10% by weight, preferably 0.5 to 5% by weight.
% by weight, more preferably 0.8 to 2% by weight. At this time, although the cationic polyacrylamide of the present invention can be used alone, it is also preferable to use it in combination with sulfuric acid, an anionic resin, etc., as necessary. These drugs can be added in any order or at the same time. Moreover, it can also be added after mixing the cationic polyacrylamide and the water-soluble anionic resin at pH 9 or higher. The addition ratio of cationic polyacrylamide and water-soluble anionic resin can be selected arbitrarily, and is 100:0 to 10 in solid content weight ratio.
: In the range of 90. The amount added is in the range of 0.005 to 3% by weight, preferably 0.01 to 1% by weight, based on the dry solid weight of the bulb. The addition location can be anywhere before the wet sheet is formed, and it is usually better to add it to a location near a part of the papermaking wire.The present invention involves terminating the reaction of the solution immediately after the Hofmann decomposition reaction, or terminating the reaction. Pulp slurry can be added without the need for In either case, the solution can be added without dilution, but if necessary, the polymer solids content may be 0.1 to 1.
It is preferable to add it after diluting it with water to 0%.

The cationic polyacrylamide of the present invention can be used as a paper strength agent by a conventionally known method. At this time, the cationic polyacrylamide of the present invention can be used alone, but if necessary Paper-making is performed in combination with sulfuric acid, anionic resin, etc., depending on the requirements.These agents can be added in any order or at the same time. It can also be added after mixing the cationic polyacrylamide and the 7-ionic resin at pH 9 or higher. The addition ratio of cationic polyacrylamide and anionic resin can be arbitrarily selected, and is in the range of 100:0 to 10:90 in terms of solid content weight ratio. The amount added is 0 for each dry solid weight of the valve.
．． 01-5% by weight, preferably 0.05-2% by weight. The addition site can be added before the wet sheet is formed, but even after the wet sheet is formed, especially when manufacturing laminated paper, it can be added by spraying or applying with a roll coater. It is also possible. In addition, in the present invention, cationic polyacrylamide is heated at high temperature.
The Hofmann decomposition reaction is carried out in a short period of time to produce a cationic polyacrylamide with even higher performance, but surprisingly, it is better than the cationic polyacrylamide obtained by carrying out the same reaction at a lower temperature for a longer period of time. The inventors have found that the paper exhibits far superior paper strength. The reason for this is not necessarily clear, but the effect was particularly remarkable when added to pulp slurry without performing a reaction termination operation, and diallylamine derivatives copolymerized with the main chain and It is thought that the N-chloro group, which is a reaction intermediate, and other functional groups generated due to high temperature directly or indirectly contribute to the development of paper strength. Therefore, it is more desirable to add the compound without stopping the reaction, but if the reaction is not stopped, it will deteriorate over time, so in that case, it is preferable to add it immediately after the reaction. "Immediately" here means that the aqueous solution after the reaction is taken out of the pipe, transported within the same pipe and added to the pulp slurry without transferring to the outside.
More specifically, the aqueous solution after the reaction may be added directly to the pulp slurry through the pipe, or a stock tank may be provided in between and temporarily 7111! After distillation, the amount may be adjusted and added. of the reaction liquid in the piping? l!
The distillation time may be within a range in which the aqueous solution after the reaction does not deteriorate. However, if the length is too long, the device for storing the liquid in S becomes large, and the features of the present invention cannot be utilized.

Therefore, in order to suitably carry out the present invention, it is preferable to add within 5 hours after the reaction, more preferably within 1 hour, and even more preferably within 10 minutes. Also,
At that time, it may be diluted with water and added depending on the concentration of cationic polyacrylamide after the reaction.It varies depending on the type of valve, speed of paper making, etc. The concentration of cationic polyacrylamide is approximately 0.1 to 10% by weight, preferably 0.5 to 10% by weight.
It is 5% by weight, more preferably 0.8-2% by weight.

Paper produced by the method described above has excellent paper strength, specifically bursting strength, biaxial strength, compressive strength, and the like. Therefore, if the paper strength enhancing agent of the present invention is applied to the paper strength increasing method of the present invention, it will be very effective when used for materials with a high proportion of waste paper such as cardboard and newspaper, and the paper strength It becomes possible to produce paper with high strength. Furthermore, by applying the present invention to papers that require strength, not just corrugated paper and newspaper, it becomes possible to produce paper with excellent paper strength. Also, if freeness is required in the paper making process, this book is for you! ! By applying this technique, it becomes possible to produce paper with high productivity and excellent paper strength.

[Effect]

According to the present invention, there is provided a paper strength enhancer that has a high paper strength effect, has a small change in effect with respect to changes in papermaking pH, and has a small change in effect with respect to dissolved components present in pulp slurry. was completed.

The reason for this is not necessarily clear, but while conventional polyacrylamide-based papermaking additives have a relatively linear structure, the polyacrylamide-based papermaking additive of the present invention has 4 chains in the main chain. Due to the introduction of class cationic polymers and the introduction of a high-temperature, short-time Hofmann decomposition reaction process, there are many partially branched structures and structures in which polymers envelop polymers. It is assumed that the 0 paper has a structure in which valves WA are intertwined with diameters of several microns to several tens of microns and lengths of hundreds of microns to several millimeters. It is said that the improvement in the paper strength effect of polyacrylamide YF, a papermaking additive, is due to the reinforcement of hydrogen bonds between valve TA fibers, and paper has a very rough structure compared to polyacrylamide papermaking additives. It is presumed that a three-dimensional structure is more suitable for reinforcing the hydrogen bonds between valve Il fibers than conventional polyacrylamide-based papermaking additives, and the polyacrylamide-based papermaking additive of this patent It is presumed that this leads to an improvement in the paper strength effect.

In addition, it is said that electrical attraction acts mainly on paper-making additives when they are fixed to pulp, and the polyacrylamide-based paper-making additive of this patent has quaternary cationic polymers in the main chain. , which further improves the chemical fixation on the valve, and the synergistic effect with the primary amino groups introduced by the Hofmann decomposition reaction reduces the effect against fluctuations in papermaking pH. It is inferred that this gives the pulp slurry the characteristics of small fluctuations in its effect on the dissolved components present in the pulp slurry.

〔Effect of the invention〕

The cationic polyacrylamide obtained by the method of the present invention is not only obtained in a short time, but also has excellent effects when applied in various industrial fields. By the way, 1
This is also clear from the examples described later.

Incidentally, the method of the present invention allows production of cationic polyacrylamide of extremely high quality in a short reaction time at high temperatures, and it goes without saying that it also has the following effects.

(1) Since the reaction time is extremely short, the reaction apparatus can be made lighter and smaller.

(2) Since the reactor can be miniaturized, the reactor can be installed at the site where cationic polyacrylamide is used, making it possible to conduct the reaction on-site.

(3) By simply changing the composition of the reaction solution, cationic polyacrylamide with varying degrees of cationicity can be produced in a short time.

(4) Furthermore, it is also possible to produce paper itself with excellent paper strength.

(5) Particularly, the effect has small fluctuations with respect to changes in papermaking pH, and also has the characteristics of small fluctuations in effect with respect to dissolved components present in the pulp slurry.

[Example] The present invention will be described below with reference to Examples. In addition, the following [2%
means % by weight unless otherwise specified.

Production example 1 250 g of 40% acrylamide aqueous solution and 700 g of distilled water
4 g while stirring and purging the inside with nitrogen gas.
Heated to 0°C. Then, a 10% aqueous RM ammonium solution and a 10% aqueous sodium bisulfite solution were added, and the polymerization reaction immediately started and the temperature of the solution rose to 85°C. After that, it was kept warm at 85°C for 1 hour, and the polymer component was 10%.
Brookfield viscosity at 25℃ is 3.200c
An aqueous polyacrylamide solution of ps was obtained.

Production Example 2 A 40% acrylamide aqueous solution (199.5 g), distilled water (771.7 g), and 70% dimethyldiallylammonium chloride (28.8 g) were placed in a four-piece flask equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen gas inlet tube. The mixture was heated to 40"C while stirring and purging the inside with nitrogen gas. Next, a 10% 1M aqueous ammonium solution and a 10% sodium bisulfite aqueous solution were added, and the polymerization reaction started immediately, and the liquid temperature rose to 85°C. After that, it was kept warm at 85°C for 2 hours, and the polymer component was 10% at 25°C.
A cationic polyacrylamide aqueous solution having a Brookfield viscosity of 3,350 cps was obtained.

Example 1 The aqueous cationic polyacrylamide polymer solution produced in Production Example 2 was reprecipitated using 10 times the volume of methanol, and 10 g of the dried powdered polyacrylamide polymer was dissolved in 140 g of distilled water. I let it happen. This solution was heated to 80° C., and while stirring, a mixed solution of 17.7 g of a 12.5% blown sodium chlorite solution, 7.5 g of a 30% sodium hydroxide solution, and 24.8 g of distilled water was added at once. Five seconds after the addition, the reaction mixture was poured into an aqueous solution containing excess sodium [sodiumite] to stop the reaction. This product is referred to as sample [A].

Example 2.3 Samples were obtained by following the same method as in Example 1, except that the Hofmann decomposition reaction was carried out at the reaction temperature and reaction time shown in Table 1. Sample each of these [
B] [C].

Table 1 Comparative Example 1 A sample was obtained in accordance with the method of Example 1 except that the polyacrylamide polymer aqueous solution produced in Production Example 1 was subjected to a Hoffman decomposition reaction at 20° C./180 seconds.

This is designated as sample [D].

Comparative Example 2 A sample was obtained in accordance with the method of Example 1 except that the aqueous solution of the polyacrylamide polymer produced in Production Example 1 was subjected to Hoffmann decomposition at 20°C/7200 seconds.

This is designated as sample [E].

Comparative Example 3 A sample was obtained in accordance with the method of Example 1, except that the aqueous solution of the cationic polyacrylamide polymer produced in Production Example 2 was subjected to a Hofmann decomposition reaction at 20"C for 180 seconds.

This is designated as sample [F].

Comparative Example 4 A sample was obtained in accordance with the method of Example 1, except that the aqueous solution of the cationic polyacrylamide polymer produced in Production Example 2 was subjected to a Hofmann decomposition reaction at 20°C/7200 seconds.

This is designated as sample [G].

Application example 1 Freeness (CSF) 390m1 Jli Lf:
pj;t Sulfuric acid band was added to a 1% pulp slurry of Neil's late H to adjust the pH to three levels. 0.1%, 1.0%, 2% sulfuric acid band to the valve of 1% pulp slurry
．． 0% added pH is 6.8, 5, 7.4 respectively
-6.

The papermaking additives produced in Examples 1 to 3 and Comparative Examples 1 to 4 were added to each of these 1% pulp slurries! 2 Paper additives were added to the bulb so that the solid content was □ and 50%. These pulp slurries were made into 150 g/g paper using a Tarapee standard sheet machine and dried. At the same time, take a part of this pulp slurry and
Freeness was measured according to P-8121. Furthermore, JIS-
The bursting strength was measured using P-8112, and the biaxial strength was measured using an internal bond tester manufactured by Kumagai Riki Kogyo. The results are shown in Table-2. Note that blank indicates that no papermaking additives were added.

Application example 2 CS F 1 piece of cardboard waste paper beaten to 420 m1
% pulp slurry was added with sulfuric acid band to adjust the pH to 5.5. When 0.2,000.4.000pp of sodium sulfate was added to this 1% pulp slurry, the electrical conductivity of each 1% pulp slurry was 0.18.
It became 2.76.5.18sS/cs. The papermaking additives produced in Examples 1 to 3 and the papermaking additives produced in Comparative Examples 1 to 4 were added to each of these 1% pulp slurries so that the solid content was 0.50% relative to the valve. did. These pulp slurries were made into paper with a basis weight of 150 g/rrr using a Tarapee standard sheet machine and dried. At the same time, take a part of this pulp slurry and
Freeness was measured according to P-8121. Furthermore, J.I.
Bursting strength is determined by S-3-P8112, JIS-P-
Compressive strength was measured using 8126. The result is 5-3
The blank indicates that no papermaking additives were added.

Application Example 3 Sulfuric acid was added to a 1% pulp slurry of cardboard waste paper beaten in 450 liters of C9F, and the pH was adjusted to 5.5. 0.100.200 PPJ of sodium lignin sulfonate was added to this 1% pulp slurry.

The papermaking additives produced in Examples 1 to 3 and the papermaking additives produced in Comparative Examples 1 to 4 were added to each of these 1% pulp slurries so that the solid content was 0.50% relative to the valve. did. These 1% pulp slurries were made into paper with a basis weight of 150 g/rrr using a Tarapee standard sheet machine and dried. At the same time, a portion of this pulp slurry was taken and its freeness was measured according to JIS-P-8121.

Furthermore, the bursting strength was determined according to JIS-P-8112.
- Compressive strength was measured using P-8126.

The results are shown in Table 4. Note that blank indicates that no papermaking additives were added.

Claims (3)

[Claims] (1) General formula (I) ▲Mathematical formula, chemical formula, table, etc.▼(I) (In the formula, R_1 and R_2 represent hydrogen or methyl group,
R and R each represent hydrogen and an alkyl group having 1 to 6 carbon atoms. X^- represents an anion of an inorganic or organic acid)
Diallylamine derivative monomer represented by 0.1 to 20
mol% and 80 to 99.9 mol% of an acrylamide monomer represented by the general formula (II) CH=C(R_5)-CONH_2(II) (in the formula, R_5 represents hydrogen or a methyl group). A papermaking additive obtained by reacting the resulting cationic copolymer with a hypohalite salt in an alkaline region at a temperature range of 50 to 110°C for a short time. (2) A method for increasing paper strength, which comprises adding the papermaking additive according to claim 1 to a pulp slurry immediately after production. (3) A method for improving drainage, which comprises adding the papermaking additive according to claim 1 to pulp slurry immediately after production.