KR20050052363A - Dispersin agent for paper pulp - Google Patents

Abstract

A papermaking agent comprising an acrylamide copolymer copolymerized with a vinyl monomer having at least an anionic group in an acrylamide, wherein the acrylamide copolymer is a saline solution containing 4% by mass of an acrylamide copolymer and a salt solution. The viscosity is higher than the viscosity of the pure solution containing the acrylamide copolymer of the same concentration as the saline solution.

Description

Papermaking agent {DISPERSIN AGENT FOR PAPER PULP}

The present invention relates to a papermaking agent. This application claims priority with respect to Japanese Patent Application No. 2003-398922 for which it applied on November 28, 2003, and uses the content here.

Background Art [0002] Papermaking methods that use disperse viscous agents have been practiced in the past to improve the dispersibility of paper materials in papermaking, such as traditional Japanese paper, toilet paper, toilet paper, and towel paper. This dispersing viscous agent is called a papermaking viscous, and for example, natural products such as extractive mucus of the root of the roots are known. However, it is rarely used industrially because of the drawbacks such as the deterioration and quality of corruption, unstable extraction, unstable price, etc. due to corruption.

Moreover, a synthetic high molecular compound can also be used as a dispersing viscosity, For example, polyethylene oxide and anionic acrylamide type polymer are used.

When papermaking a toilet paper or towel paper, cationic high molecular weight compounds, such as a wet strength enhancer, are added to a paper material in many cases, and cationic agents, such as a softening agent, dye, and a pigment, may be added. Therefore, when a papermaking agent containing an anionic acrylamide polymer is used in a paper containing a cationic high molecular compound or a cationic drug, the paper fibers are agglomerated by the action of electric charge, which makes dispersion of papermaking difficult. Had a problem. In addition, in the case of toilet paper for toilets with relatively low use of the above additives, anionic acrylamide-based polymer may be used. However, when the toilet paper for toilet paper and toilet paper are produced together with one kind of papermaking agent, wet paper strength When white water containing an enhancer is mixed, there is a problem in that anionic acrylamide polymer cannot be used.

In general, nonionic papermaking agents without charge action have been used. As a specific nonionic papermaking agent, the polyethylene oxide type papermaking agent is mentioned, for example. Currently, polyethylene oxide is used in most cases as a nonionic papermaking agent.

In addition, a method using a combination of polyethylene oxide and a nonionic polymer polyacrylamide has been proposed in that it is possible to obtain paper with significantly improved quality than when using polyacrylamide alone (for example, Japanese Patent Publication No. 1977). -15681).

Also, a papermaking viscous comprising a copolymer comprising an acrylamide monomer unit and an N-vinylcarboxylic acid amide monomer unit has been proposed (for example, Japanese Patent Laid-Open No. 2000-290892).

Furthermore, the viscosity of the saline solution containing the acrylamide nonionic (co) polymer and the saline solution is higher than the viscosity of the pure solution containing the acrylamide nonionic (co) polymer in the same concentration as the saline solution. It has been proposed to use a amide nonionic (co) polymer to form a papermaking viscosity using an acrylamide nonionic (co) polymer whose hydrolysis is suppressed (see Japanese Patent Laid-Open No. 2003-253587).

However, the addition of polyethylene oxide as a papermaking agent has problems such as the difficulty in stable papermaking and its high price since polyethylene oxide causes a viscosity decrease depending on the dissolution conditions. In addition, since polyethylene oxide foamed during the papermaking process, a large amount of antifoaming agent that suppressed foaming had to be added.

In the invention described in Japanese Patent Publication No. 1977-15681, the foaming of polyethylene oxide is reduced, but as the paper containing a cationic high molecular compound or a cationic agent, such as paper on toilet paper or towel paper, polyethylene oxide alone It was not possible to obtain a sufficiently uniform paper quality as compared to the above. Moreover, the molecular weight of polyacrylamide was low, and there existed a fault which the addition amount of the papermaking viscous increased.

In the invention described in Japanese Patent Application Laid-Open No. 2000-290892, there are problems such that N-vinyl carboxylic acid amide is expensive or it is difficult to obtain N-vinyl carboxylic acid amide of stable quality. Also, compared with polyethylene oxide, the aggregation of the stock fibers tended to be slightly stronger, and the papermaking performance was not sufficient.

Since the paper-based viscous agent of Unexamined-Japanese-Patent No. 2003-253587 has a dissolution rate and requires a long time for melt | dissolution, when it is used when it is inadequate, there existed a problem that paper troubles generate | occur | produced by unsealed seafood.

In addition, nonionic polyacrylamide-based papermaking agents have a slow dissolution rate compared to polyethylene oxide papermaking agents. For this reason, when mixing and using a polyethylene oxide papermaking agent and a polyacrylamide type papermaking agent, it is necessary to prolong the stirring time more than the case of polyethylene oxide alone. If the stirring force of the aqueous solution containing polyethylene oxide is enhanced or the stirring time is extended, the shear force due to stirring is exerted more than necessary on the polyethylene oxide portion, which causes a decrease in viscosity, and the setting of the dissolution conditions is difficult. There was a flaw that was difficult.

The present invention has been made in view of the above circumstances. For example, in papermaking such as toilet paper and toweling paper, even if a cationic polymer or a cationic agent is added, dispersibility can be imparted to the paper fiber, and thus the stability of papermaking It is possible to improve manufacturing efficiency. It is an object of the present invention to provide a papermaking point which is inexpensive, high performance and easy to handle.

MEANS TO SOLVE THE PROBLEM As a result of investigating variously in order to solve the said subject, the present inventors obtained the acrylamide type copolymer which the dissolution rate improved dramatically by copolymerizing an extremely small amount of anionic monomer with an acrylamide. Using acrylamide copolymer, it is possible to prepare a papermaking viscous agent which does not generate or hardly aggregate paper fibers even when used in combination with a cationic polymer or a cationic agent. The present invention was completed by finding a point related to the viscosity and the viscosity value of the pure solution.

That is, the papermaking viscous agent of the present invention comprises an acrylamide copolymer copolymerized with a vinyl monomer having at least an anionic group in the acrylamide, wherein the acrylamide copolymer satisfies the following viscosity conditions.

(Viscosity condition)

The viscosity of the saline solution containing 4% by mass of the acrylamide copolymer and the saline solution is higher than the viscosity of the pure solution containing the acrylamide copolymer of the same concentration as the saline solution.

Here, the amount of the vinyl monomer having an anionic group can be arbitrarily selected, but it is preferable to have 0.1 to 1.5 mol% of the vinyl monomer relative to 100 mol% of the acrylamide copolymer.

The vinyl monomer may be arbitrarily selected, but is preferably acrylic acid (salt) and / or acrylamide-2-methylpropanesulfonic acid (salt).

It is preferable that the viscosity of the 1 mass% pure water solution which contains 1 mass% of said acrylamide type copolymers in pure water is 2000 mPa * s or more.

Moreover, it is preferable that the papermaking viscosity of this invention contains a polyethylene oxide further. In addition, the acrylamide copolymer is preferably 20 to 75% by mass and polyethylene oxide is 25 to 80% by mass.

Hereinafter, the present invention will be described in detail.

The papermaking viscosity of the present invention includes a water-soluble acrylamide copolymer.

As an acrylamide type copolymer, the viscosity of the saline solution containing the said acrylamide type copolymer and 4 mass% of salts contains the viscosity of the pure solution which contains the acrylamide type copolymer of the same density | concentration in the pure water as the viscosity of the said saline solution. The higher one is used.

In addition, salt as used herein refers to sodium chloride. In addition, in this application, the acrylamide copolymer copolymerized with the vinyl monomer which has an anionic group at least in an acrylamide may be described simply as an acrylamide copolymer.

In the present invention, for example, the viscosity of a 1 mass% saline solution containing 1 mass% of an acrylamide copolymer and 4 mass% of salt is the viscosity of a 1 mass% pure solution containing 1 mass% of an acrylamide copolymer in pure water. The acrylamide type copolymer higher than 100 mPa * s can be used. Moreover, it is more preferable to use the acrylamide type copolymer high 150 mPa * s or more, and it is still more preferable to use the acrylamide type copolymer high 200 mPa * s or more.

In the present invention, "viscosity" means an acrylamide-based copolymer is added to 4 mass% saline or pure water and stirred for 3 hours, and the resulting solution is a type B viscometer (rotor No. 2, rotating at 25 ° C). 6 rpm).

As described above, by measuring the viscosity of the saline solution and the pure water solution of the acrylamide-based copolymer, the degree of anionic group content of the acrylamide-based copolymer can be known from the following reasons, and the acrylamide-based copolymer is a cationic component. It is possible to obtain a criterion of a tendency to aggregate with and cause aggregation of the stock.

That is, when the acrylamide copolymer has anionic groups such as carboxyl group and sulfonic acid group, when the acrylamide copolymer is dissolved in pure water, the acrylamide copolymer molecule is elongated by the intramolecular electrostatic repulsion of the anionic group. As a result, the area of the molecule in the aqueous solution increases, and the viscosity of the liquid increases. On the other hand, when dissolved in an electrolyte solution such as saline, the intramolecular electrostatic repulsion of the anionic group in the molecule is suppressed, so that the increase in the liquid viscosity due to the elongation of the molecule is suppressed. On the other hand, when the acrylamide copolymer does not contain an ionic group, electrostatic repulsion in the pure water does not occur originally, and the viscosity increase when dissolved in the pure water does not occur. Therefore, compared with the case where the acrylamide copolymer is dissolved in an aqueous solution containing 4% by mass of an electrolyte such as saline, the viscosity of the pure solution is lower.

The more anionic groups contained in the acrylamide-based copolymer, the greater the electrostatic repulsion, and the higher the viscosity increase in pure water.

Generally, the acrylamide-based copolymer used in papermaking viscosities does not have an anionic group in terms of preventing the reaction with cationic materials. On the other hand, in the case of pure nonionics, the dissolution rate tends to be slow. .

The inventors of the present invention have examined the conditions for satisfying this yield rate, and as a result, the solubility of the acrylamide-based copolymer is rapidly improved by containing a very small amount of ionic groups, while any limited amount of anionic groups in the actual papermaking system It was found that the point of not causing rapid agglomeration and its degree of agglomeration are related to the viscosity of the saline solution and the viscosity value in pure water. That is, when comparing the viscosity of the said saline solution with the viscosity of the said pure water solution with respect to the acrylamide type | system | group copolymer, when the viscosity of the said saline solution is high, agglomeration of a paper material will not produce severely.

The acrylamide-based copolymer having a viscosity of the saline solution higher than that of the pure water solution specifically includes 0.1 to 1.5 mol% of a vinyl monomer having an anionic group with respect to 100 mol% of the acrylamide-based copolymer. You can get it.

When the amount of the vinyl monomer having an anionic group is less than 0.1 mol%, the effect of improving the dissolution rate of the papermaking viscous agent is small, and when the amount of the vinyl monomer exceeds 1.5 mol%, the viscosity of the pure water solution is increased, and the aggregation of the paper in the practical use example Cause. The amount of the vinyl monomer is more preferably 1.0 mol% or less, and most preferably 0.8 mol% or less. Moreover, it is more preferable that a lower limit is 0.4 mol% or more.

In addition, the acrylamide copolymer of the present application may contain a nonionic vinyl monomer having no other anionic group.

Examples of the vinyl monomer having an anionic group include acrylic acid, acrylamide-2-methylpropanesulfonic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, salts thereof, and the like. Or 2 or more types can be used. Among them, acrylic acid (salt) and / or acrylamide-2-methylpropanesulfonic acid (salt) are preferable because industrially inexpensive and high-quality ones can be obtained, and acrylic acid (salt) is most preferred, but contains anionic groups. If it is a monomer, it is not limited to this.

In addition, in this invention, acrylic acid (salt) and acrylamide-2-methylpropanesulfonic acid (salt) are acrylic acid and / or acrylate, acrylamide-2-methylpropanesulfonic acid, and / or acrylamide-2- Methyl propane sulfonate is shown, respectively.

Moreover, although it is preferable that the anionic group takes the form of a salt, it does not need to be partially neutralized. The vinyl monomer having such an anionic group is introduced into the acrylamide copolymer by copolymerization. In addition, it is also possible to introduce an anionic group into the acrylamide copolymer by the method of hydrolysis of the acrylamide residue, but since the target amount of introduction is small and the allowable width is narrow, the hydrolysis is suppressed as much as possible. It is preferable to introduce an anionic group.

The acrylamide copolymer may be a copolymer of only a vinyl monomer containing an acrylamide and an anionic group, or may be a copolymer with other nonionic monomers. As said nonionic monomer, methacrylamide, N-vinyl acetoamide, N-vinyl formamide, N-vinyl-N-methylacetoamide, N-vinyl-N-methylformamide, and N-methyl (meth) acrylamide , N, N-dimethyl (meth) acrylamide, methyl (meth) acrylate, vinyl acetate, allyl alcohol, N-vinylpyrrolidone, isopropyl acrylamide, diacetone acrylamide, acrylonitrile and the like Can be. Nonionic monomers other than acrylamide may be used alone or in combination of two or more.

As for the acrylamide, 50 mass% or more is preferable with respect to the total monomer which comprises a copolymer, 70 mass% or more is more preferable, Especially 90 mass% or more is preferable. Generally, the higher the proportion of acrylamide, the more likely the molecular weight of the polymer to be obtained is, and a highly viscous acrylamide copolymer is obtained.

In addition, since the acrylamide copolymer is used as a papermaking agent, the higher the viscosity in the range that does not deteriorate the solubility, the more preferable. Specifically, the viscosity of the 1 mass% pure water solution is preferably 2000 mPa · s or more. More preferably, it is 2500 mPa * s or more, More preferably, it is 3000 mPa * s or more. Moreover, it is preferable that the viscosity of the saline solution containing the said acrylamide type copolymer and 4 mass% of salts is also 2000 mPa * s or more.

The papermaking viscosity of the present invention may further contain components other than the acrylamide-based copolymer, and may include, for example, polyethylene oxide, camphor extract, or the like, which are usually used for papermaking applications, alone or in combination of two or more thereof. It may be. However, in order to express the effect of this invention, it is preferable that components other than an acrylamide type copolymer are nonionic substances.

The papermaking viscous agent of this invention contains a polyethylene oxide further, It is preferable that the said acrylamide type copolymer is 20-75 mass%, and the polyethylene oxide is 25-80 mass%.

Since the acrylamide-based copolymer used in the present invention has a high dissolution rate, when the acrylamide-based copolymer and polyethylene oxide are mixed and used as a papermaking agent, the acrylamide-based copolymer has a dissolution rate of the acrylamide-based copolymer. The difference is small and there is no need to overextend the time to dissolve. For this reason, deterioration of the polyethylene oxide at the time of melt | dissolution is suppressed to the minimum. In addition, when the acrylamide copolymer and polyethylene oxide are included, a synergistic effect may be obtained that the performance of dispersing the stock is improved compared to the acrylamide copolymer alone or polyethylene oxide alone. Moreover, the problem of foaming of polyethylene oxide does not arise either.

When the content ratio of polyethylene oxide is 80 mass% or less, the cost of the papermaking viscosity becomes low. Moreover, when the content rate of polyethylene oxide is 25 mass% or more, the value of the pipette viscosity of the papermaking viscosity which shows the performance as papermaking viscosity becomes larger than the value of polyethylene oxide alone. In other words, stable papermaking can be achieved with a smaller amount of papermaking agent.

33 mass% is more preferable, and, as for the minimum of a polyethylene oxide content rate, 40 mass% is especially preferable. 75 mass% is more preferable, and, as for the upper limit of the content rate of polyethylene oxide, 67 mass% is especially preferable.

In addition, as the content ratio of polyethylene oxide and acrylamide copolymer is close to one to one, the pipette viscosity of the polyethylene oxide aqueous solution alone, the pipette viscosity of the acrylamide copolymer alone aqueous solution, or the polyethylene oxide and acrylamide copolymer The synergistic effect by which the pipette viscosity of the papermaking viscosity improves rather than the average value according to the content rate in the papermaking viscosity.

The method for producing the acrylamide-based copolymer used in the present invention is not particularly limited as long as an acrylamide-based copolymer having a viscosity of the saline solution is higher than that of a pure solution can be obtained, and known polymerization methods such as aqueous solution polymerization and suspension polymerization are known. Can be adopted. Although the general polymerization method of an acrylamide type copolymer is aqueous solution polymerization using a radical polymerization initiator and a photoinitiator, aqueous solution polymerization using a photoinitiator is especially preferable.

In aqueous polymerization, the concentration of acrylamide in the aqueous solution (hereinafter abbreviated as "monomer concentration") is usually 10 to 75 mass%, but the lower limit of the monomer concentration is preferably 15 mass% or more, more preferably 20 mass% or more. desirable. On the other hand, as for the upper limit of monomer concentration, 50 mass% or less is preferable.

When the monomer concentration is high, the productivity tends to be improved, and when the monomer concentration is low, the solubility of the polymer obtained tends to be improved.

Usually, as a polymerization initiator, a photoinitiator, an azo initiator, a redox initiator, etc. can be used.

As a photoinitiator, (alpha)-hydroxy ketones, an acyl phosphine oxide compound, etc. can be used. Examples of these compounds include azobisisobutyronitrile, azobisisovaleronitrile, 2,2-azobis (2-amidinopropane) dihydrochloride, 2,2-azobis [2-methyl-N -(2-hydroxyethyl) -propionamide], 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- [4- (2-hydroxy Ethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethyl Benzoyl diphenyl phosphine oxide, benzoin, benzoin ethyl ether, benzophenone and the like.

Azo initiator can be used as a photoinitiator or a thermal decomposition polymerization initiator, for example, azobisisobutyronitrile, azobisisovaleronitrile, 2,2'-azobis (2-amidinopropane) dihydrochloride , 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl)- Propionamide, and the like.

Examples of redox-based initiators include peroxides such as persulfate, t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide and lauryl peroxide, sulfite, hydrogen sulfite, thiosulfate, sodium formaldehyde sulfoxylate and ferrous sulfate. And combinations with reducing agents such as glucose and amines.

The polymerization initiators may be used alone or in combination of two or more thereof. The addition amount of a polymerization initiator is determined by the combination of the molecular weight of a polymer obtained, superposition | polymerization time, or residual monomer amount, for example, in the case of a photoinitiator, it is about 1-1000 ppm normally with respect to all monomers.

Usually, since the papermaking viscous is used as a powder, the obtained acrylamide copolymer can be dried and powdered. Although a drying method is not specifically defined, In order to prevent the hydrolysis or the deterioration of the solubility of an acrylamide type copolymer, it is preferable to take the drying method with a small heat load.

The acrylamide-based copolymer is followed by drying to pulverize to powder. The particle size is not particularly specified. If the particle size is too large, it takes time to dissolve, and if it is small, problems such as powder generation may occur.

In addition, the acrylamide copolymer of the present invention may be used in any state as long as there is no problem in use, and may be used in any shape or size.

It is preferable that the obtained acrylamide copolymer has good solubility. Here, the solubility was measured by adding 0.1% by mass of the acrylamide-based copolymer to 3 kg of water, stirring the mixture for 3 hours, filtering it with a mesh of 180 μm mesh, and measuring the mass of the hydrous gel supplemented with the mesh. The smaller the quantity, the better. Usually, the hydrogel mass is 20 g or less, preferably 10 g or less, and more preferably 6 g or less.

The powder of the acrylamide-based copolymer obtained in the present invention can be used alone or in combination with polyethylene oxide as a viscous agent for papermaking.

In the papermaking point of the present invention, when the polyethylene oxide is further contained as described above, the mixing of the polyethylene oxide and the acrylamide-based copolymer is pre-mixed between the powders, or the powders are separately supplied at the time of dissolution to dissolve the bath. You can also mix inside. In addition, the polyethylene oxide and the acrylamide copolymer may be dissolved separately and the aqueous solutions may be mixed. In the case of mixing in an aqueous solution state, stirring and mixing are necessary to make it more uniform.

Moreover, the papermaking viscosity of this invention can also be comprised only by the said acrylamide type copolymer. This papermaking agent may be distributed, and other commercially available papermaking agents such as polyethylene oxide papermaking agents and powders may be mixed with each other during papermaking, or may be mixed in a dissolution tank for use in papermaking. Thus, even if it is mixed with another papermaking viscosity, the papermaking viscosity of this invention can exhibit a favorable performance, without causing deterioration of another papermaking viscosity.

As mentioned above, since the viscosity of the said saline solution of the acrylamide type copolymer which contains the acrylamide type copolymer of this invention is higher than the viscosity of a pure water solution, there are few monomeric units which have an anionic group in an acrylamide type copolymer.

As a result, aggregation of the paper fiber when used together with a cationic agent is prevented, dispersion in papermaking becomes favorable, and stability of papermaking and manufacturing efficiency can be improved. In addition, there is an advantage that the dissolution rate is fast and easy to use due to the action of the monomer unit having an anionic group present in a small amount, and the insolubles are small. It is also inexpensive and has excellent papermaking performance.

Moreover, the papermaking point of the present invention does not cause the same problem of deterioration of polyethylene oxide as in the case of further containing polyethylene oxide. Since the polyethylene oxide can be further included, the thickening effect and the performance of dispersing the paper fibers are further improved, so that not only the stability of papermaking and the production efficiency are improved, but also the amount of papermaking viscous used is reduced.

Example

Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these.

Example 1

[Preparation of Acrylamide Copolymer]

A 0.4 mol% acrylate-containing acrylamide copolymer composed of a copolymer of acrylamide and sodium acrylate was prepared as follows.

In a 1 liter Erlenmeyer flask, 329.05 g of 50 mass% acrylamide aqueous solution, 1.35 g of 50 mass% acrylic acid aqueous solution, 1.14 g of 33 mass% aqueous sodium hydroxide solution, and 50 ppm of disodium phosphite (hereinafter, the ppm notation indicates the mass ratio to the total liquid volume) 413 g of aqueous solution containing was added to adjust the aqueous monomer solution.

Under shading, 10 ppm of 2-hydroxy-2-methyl-1-phenylpropane-1-one and 150 ppm of 2,2'-azobis (2-amidinopropane) dihydrochloride were added to the aqueous monomer solution, and the Erlenmeyer flask was added. The solution was placed in a constant temperature water bath at 10 ° C, and dissolved oxygen in the aqueous solution was replaced with nitrogen gas for 30 minutes as it is.

At the circumferential edge of the stainless plate having a thickness of 1 mm, a container was prepared in which a rubber rod having a 24 mm side was attached to the inner bottom of the stainless plate to have a square of 200 × 200 mm. Into the inside of the vessel was a 16 μm thick transparent film (laminated film consisting of 12 μm thick polyethylene terephthalate and 4 μm thick polyvinylidene chloride), and the aqueous solution of the polymerizable monomer was supplied onto the film. The surface of the aqueous solution was covered with a light transmitting film of the same kind as described above so as to contact the aqueous solution. The thickness of the layer consisting of aqueous monomer solution was 10 mm. Further, the rear of the stainless steel plate was cooled by spraying water at 10 ° C before supplying the aqueous monomer solution, and the temperature of the stainless steel plate was adjusted to 10 ° C. Moreover, 10 degreeC water was sprayed continuously until completion | finish of superposition | polymerization.

The 20 W type fluorescent chemical lamp was installed above the container supplied with the aqueous monomer solution. The fluorescent chemical lamp adjusted so that irradiation intensity might be 5 W / m <^2> previously in aqueous solution surface was turned on for 10 minutes. Next, the fluorescent chemical lamp adjusted so that irradiation intensity might be 10 W / m <^2> on the surface of aqueous solution was turned on for 20 minutes. Moreover, the fluorescent chemical lamp adjusted so that irradiation intensity might be 60 W / m <^{2> on the} surface of aqueous solution was turned on for 30 minutes, superposition | polymerization was completed and the hydrous gel sheet containing a polymer was obtained. The peak temperature at the time of superposition | polymerization which aqueous solution or hydrous gel-like sheet reached was 55 degreeC.

The obtained hydrous gel sheet was cut with scissors and dried with a hot air dryer at 60 deg. Further, the dried product was pulverized with a wiley grinder to obtain a powdery acrylamide copolymer.

[Evaluation of Aqueous Physical Properties of Acrylamide Copolymer]

(1) Measurement of the viscosity of pure water solution

The viscosity of the 1 mass% pure water solution of the obtained acrylamide type copolymer was measured.

495 g of pure water was put into a 500 ml beaker, and 5 g of the acrylamide copolymer obtained above was added under stirring, and stirring was continued for 3 hours, and the viscosity was measured with the Brookfield viscometer at 25 degreeC. At this time, the rotor No. 2 was set to 6 rpm.

(2) Viscosity measurement of saline solution

The viscosity of the 1 mass% saline solution of the obtained acrylamide copolymer was measured. 475 g of pure water was added to a 500 ml beaker, and 5 g of acrylamide copolymer was added under stirring, followed by stirring for 3 hours. Furthermore, after adding 20 g of salt and stirring for 30 minutes, the viscosity was measured with the Brookfield viscometer at 25 degreeC. The rotor used at this time was the same as above.

(3) Measurement of water insoluble components

2997 g of tap water was added to a 3000 ml beaker, and 3 g of an acrylamide-based copolymer was added thereto under stirring to dissolve for 3 hours, filtered through a mesh screen of 180 μm of mesh scale, and left for 10 minutes before measuring mass. And the mass of the gold network measured beforehand was subtracted and it was set as the mass of a water-insoluble component.

(4) measurement of dissolution time

2997 g of tap water was added to a 3000 ml beaker, and 3 g of acrylamide-based copolymer was added thereto under stirring to dissolve for a predetermined time, and then filtered through a mesh screen of 180 μm of mesh, and left for 10 minutes. Was measured. The mass minus the mass of the previously measured gold net was measured. The measurement was carried out at a dissolution time of 30 minutes, 60 minutes, 90 minutes, 120 minutes, 150 minutes, and 180 minutes, and the dissolution time was defined as the time at which the mass did not substantially change.

[Adjustment of Paper Slurry]

0.2 mass% pulp slurry was adjusted using NBKP (softwood pulp) of 650 ml CFS (Canada Standard Yeosu) as a raw material. At this time, 0.2 mass% of polyamide polyamine epichlorohydrin, which is a cationic wet strength enhancer, was added to the pulp as an additive agent, and the mixture was sufficiently stirred to obtain a pulp slurry.

[Performance evaluation of papermaking point]

The performance was evaluated for the paper-based viscosity of the acrylamide-based copolymer powder obtained above.

A papermaking viscous aqueous solution dissolved at a concentration of 0.1% by mass with respect to the paper slurry was added so as to be 2 ppm as a net component of the papermaking viscous, and the paper coagulability and freeness of the slurry solution mixed with stirring were measured.

(1) stock cohesiveness

The shape of the paper material when the paper slurry solution to which the papermaking agent was added was stirred with a Jar tester was visually determined. Evaluation criteria are shown below. In addition, the following reference | standard is so preferable that it exists in the upper part (for example, (as follows) shows the most preferable thing).

(Double-circle): Since there is no cohesion, there is no problem at the time of use.

(Circle): Although it aggregates slightly, there is no problem at the time of use.

(Triangle | delta): There exists a possibility that the quality of a papermaking product may be disturbed by being aggregated slightly.

X: Agglomerated and cannot be used for papermaking.

(2) Yeosu

A Buchner funnel having a diameter of 62 mm with a filter cloth was installed on a 500 ml measuring cylinder, and the stock slurry mixed with a papermaking agent was poured into the Buchner funnel to measure the amount of water.

Here, the smaller the amount of free water, the better the dispersibility of the paper stock, and the smaller the amount of the viscous agent necessary for providing a constant dispersibility to the paper.

(3) the quality of the paper

The paper of 13.0 g / m <^2> basis weights which were paper-making by the continuous Yankee paper machine was visually judged using the paper slurry solution which added the papermaking agent directly without passing through a filter etc. Evaluation criteria are shown below.

◎: uniform and excellent.

○: good.

(Triangle | delta): Unevenness.

X: It is a paper which cannot be made paper due to defect or a hole was punched.

(4) foamability

Air was blown into the aqueous solution in which the papermaking agent was dissolved at a concentration of 0.1% by mass, and the presence or absence of foaming was visually evaluated. Evaluation criteria are shown below.

○: no foaming.

(Triangle | delta): It foams to some extent and the addition of the defoaming agent is needed for papermaking.

X: Foaming is large and a large amount of antifoamer is needed for papermaking.

The evaluation result of the papermaking agent was shown in Table 2 collectively.

Example 2

The polymerization was carried out in the same manner as in Example 1 except that 328.38 g of a 50 mass% acrylamide aqueous solution, 2.02 g of a 50 mass% acrylic acid aqueous solution and 1.70 g of a 33 mass% sodium hydroxide aqueous solution were polymerized in the same manner as in Example 1 to contain 0.6 mol% of acrylate. An acrylamide copolymer was obtained. Evaluation results of the aqueous solution properties of the acrylamide-based copolymer are shown in Table 1, and evaluation results of the paper-based viscous agent composed of the obtained acrylamide-based copolymer are shown in Table 2, respectively.

Example 3

The polymerization was carried out in the same manner as in Example 1 except that 327.72 g of a 50% by mass acrylamide aqueous solution, 2.68g of a 50% by mass aqueous acrylic acid solution and 2.25g of a 33% by mass sodium hydroxide aqueous solution were polymerized in the same manner as in Example 1 to contain 0.8 mol% of an acrylate. An acrylamide copolymer was obtained. Evaluation results of the aqueous solution properties of the acrylamide-based copolymer are shown in Table 1, and evaluation results of the paper-based viscous agent composed of the obtained acrylamide-based copolymer are shown in Table 2, respectively.

Example 4

The polymerization was carried out in the same manner as in Example 1, except that 327.06 g of a 50% by mass acrylamide aqueous solution, 3.34 g of a 50% by mass aqueous acrylic acid solution and 2.81g of a 33% by mass aqueous sodium hydroxide solution were polymerized in the same manner as in Example 1 Got. Evaluation results of the aqueous solution properties of the acrylamide-based copolymer are shown in Table 1, and evaluation results of the paper-based viscous agent composed of the obtained acrylamide-based copolymer are shown in Table 2, respectively.

Example 5

The polymerization was carried out in the same manner as in Example 1 except that 325.38 g of 50 mass% acrylamide aqueous solution, 5.02 g of 50 mass% acrylic acid aqueous solution and 4.23 g of 33 mass% sodium hydroxide aqueous solution were polymerized in the same manner as in Example 1, and the acrylamide-containing acrylamide copolymer containing 1.5 mol% Got. Evaluation results of the aqueous solution properties of the acrylamide-based copolymer are shown in Table 1, and evaluation results of the paper-based viscous agent composed of the obtained acrylamide-based copolymer are shown in Table 2, respectively.

Comparative Example 1

Polymerization was carried out in the same manner as in Example 1 except that 330.40 g of 50 mass% acrylamide aqueous solution, 0 g of 50 mass% acrylic acid aqueous solution, and 0 g of 33 mass% sodium hydroxide aqueous solution were obtained, thereby obtaining an acrylamide-containing acrylamide copolymer containing 0 mol% of acrylate. . Evaluation results of the aqueous solution properties of the acrylamide-based copolymer are shown in Table 1, and evaluation results of the paper-based viscous agent composed of the obtained acrylamide-based copolymer are shown in Table 2, respectively.

Comparative Example 2

The polymerization was carried out in the same manner as in Example 1 except that 323.69 g of 50 mass% acrylamide aqueous solution, 6.71 g of 50 mass% acrylic acid aqueous solution and 5.65 g of 33 mass% sodium hydroxide aqueous solution were polymerized in the same manner as in Example 1, and the acrylamide-containing acrylamide copolymer containing 2.0 mol% Got. The evaluation results of the aqueous solution properties of the acrylamide copolymer are shown in Table 1, and the evaluation results of the papermaking viscosities are shown in Table 2, respectively.

Comparative Example 3

The polymerization was carried out in the same manner as in Example 1 except that 313.65 g of 50 mass% acrylamide aqueous solution, 16.75 g of 50 mass% acrylic acid aqueous solution, and 14.10 g of 33 mass% sodium hydroxide aqueous solution were polymerized in the same manner as in Example 1, and 5.0 mol% of acrylamide-based acrylamide copolymer was obtained. Got. Evaluation results of the aqueous solution properties of the acrylamide-based copolymer are shown in Table 1, and evaluation results of the paper-based viscous agent composed of the obtained acrylamide-based copolymer are shown in Table 2, respectively.

As shown in Table 1 and Table 2 above, a saline solution containing an acrylamide copolymer copolymerized with a vinyl monomer having an anionic group in the acrylamide and containing 4% by mass of the acrylamide copolymer and salt In Examples 1 to 5 whose viscosity is higher than the viscosity of a pure solution containing an acrylamide copolymer having the same concentration as that of the saline solution in pure water, the paper cohesiveness and freeness are low, the quality of paper is excellent, and the dissolution time This short and excellent paper-cutting agent was obtained.

On the other hand, Comparative Example 1, which had no anionic group, was excellent in papermaking performance, but was difficult to handle because of its slow dissolution rate and time consuming dissolution. In addition, in Comparative Examples 2 and 3, which contained many anionic groups and the viscosity of the pure water solution of the acrylamide-based copolymer was higher than that of the saline solution, paper cohesiveness and freeness were high, and paper quality was poor.

Examples 6 to 10 and Comparative Example 4

The polyethylene oxide and the acrylamide copolymer used in Example 2 were mixed in the mixing | blending ratio shown in Table 3, it was set as the papermaking viscosity, and these papermaking viscosity was evaluated similarly to Example 1. As the polyethylene oxide, a commercially available alkox (trade name, manufactured by Meisei Chemical Works, Ltd.) was used.

The results are summarized in Table 3. In addition, in Table 3, PEO and PAM represent the polyethylene oxide and the acrylamide type copolymer used in Example 2, respectively.

As shown in Table 3, the papermaking viscosities of Examples 6 to 10 containing polyethylene oxide and the acrylamide copolymer of Example 2 were excellent in paper cohesiveness, free water, paper quality, and foamability was reduced. It was a papermaking agent.

On the other hand, the comparative example 4 which consists only of polyethylene oxide fell in terms of foamability.

As is apparent from the above, the papermaking viscosities of Examples 1 to 10 can impart high dispersibility by the paper in the same amount compared to the papermaking viscosities obtained in Comparative Examples 1 to 4, thereby realizing good papermaking and handling. The castle was excellent.

Industrial availability

Papermaking viscosities of the present invention can be preferably used in industries where polyethylene oxide, polyacrylamide, and anionic acrylamide-based polymers are used as thickeners, and in particular, toilets that have previously been difficult to apply one type of papermaking viscous. It can also be preferably used universally among production items such as toilet paper and toilet paper. That is, it can be used for imparting dispersibility to the paper fiber when papermaking toilet paper, towel paper, toilet paper, and the like. For example, in papermaking such as toilet paper and toweling paper, even if a cationic polymer or a cationic agent is added, dispersibility can be imparted to the paper fiber, and it is possible to improve the stability and manufacturing efficiency of papermaking. In addition, it provides a papermaking agent that is easy to handle.

Papermaking viscosities of the present invention in papermaking such as toilet paper and towel paper, even if a cationic polymer or a cationic agent is added, the same or more than the nonionic papermaking viscous described in Japanese Patent Laid-Open No. 2003-253587 The acidity is imparted to the paper fiber, the papermaking stability and the production efficiency can be improved, and the dissolution rate is dramatically improved. By improving the dissolution rate, it is possible to reduce the problem due to insoluble components during use and to shorten the dissolution time.

Moreover, when polyethylene oxide is contained in the papermaking viscosity of this invention, deterioration can be stopped to the minimum and the performance which disperse | distributes a paper material can be improved.

Claims (8)

An acrylamide copolymer copolymerized with a vinyl monomer having at least an anionic group in the acrylamide, A viscous agent for papermaking, wherein the viscosity of the saline solution containing 4% by mass of the acrylamide copolymer and saline satisfies the viscosity condition higher than the viscosity of the pure solution containing the acrylamide copolymer having the same concentration as the saline solution. . The method of claim 1, The papermaking viscosity agent which has 0.1-1.5 mol% of vinyl monomers with respect to 100 mol% of acrylamide copolymers. The method of claim 1, The paper-based viscosity of the vinyl monomer is at least one selected from the group consisting of acrylic acid, acrylate, acrylamide-2-methylpropanesulfonic acid, and acrylamide-2-methylpropanesulfonic acid salt. The method of claim 1, The papermaking viscosifier whose viscosity of the 1 mass% pure water solution which contains 1 mass% of acrylamide type copolymer in pure water is 2000 mPa * s or more. The method of claim 1, The papermaking viscosifier which further contains polyethylene oxide, is 20-75 mass% of acrylamide type copolymers, and 25-80 mass% of polyethylene oxide. The method of claim 1, The viscosity of 1 mass% saline solution containing 1 mass% of acrylamide copolymer and 4 mass% of salt is 100 mPa * s more than the viscosity of 1 mass% pure water solution containing 1 mass% of acrylamide copolymer in pure water High grass paper additives. The method of claim 1, The manufacturing agent for papermaking whose 50 mass% or more is acrylamide with respect to the total monomer which comprises an acrylamide type copolymer. The method of claim 1, Papermaking agent wherein the anionic group is a carboxyl group.