JPH10251990A - Additive for paper making and production of paper or cardboard paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a paper or a cardboard paper excellent in paper strength by adding an additive for paper making, obtained by blending starches containing phosphoric acid group with a (meth)acrylamide derivative containing phosphoric acid group, into a pulp slurry. SOLUTION: This method for preparing an additive for paper making, it to blend 50-98wt.% starches containing phosphoric acid group such as a urea phosphoric acid ester starch liquid based on its solid portion with 50-2wt.% (meth)acrylamide derivative containing phosphoric acid group, obtained by copolymerizing (meth)acrylamide with 1-20mol% monomer containing phosphoric acid group such as mono [2-(meth)acyloyloxyethyl] acid phosphate based on its solid portion to obtain the additive for the paper making, having 100-20000cps viscosity (at 25 deg.C) in the case of having 10wt.% concentration of the mixed liquid. The additive is added to a pulp slurry for obtaining a paper or a cardboard paper having an extremely marked paper strength reinforcing effect.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a papermaking additive and a method for producing paper or paperboard. The papermaking additive of the present invention can be used as a papermaking filtration agent, paper strength enhancer, filler retention agent, size fixing agent, and the like. In particular, the papermaking additive of the present invention has a high paper strength improving effect as a paper strength enhancer.

[0002]

2. Description of the Related Art Conventionally, starches have been used as paper strength agents. In many cases, starches are gelatinized and added to the pulp slurry in the form of a sizing solution. However, since starch starch liquid has poor storage stability, there is a problem in that the starch liquid gels with time or degrades due to water separation. Therefore, not only the desired paper strength effect cannot be obtained, but also it is necessary to gelatinize the starch powder on site,
This has led to a decline in productivity and workability of paper companies.

[0003] In order to solve these problems, attempts have been made to improve the storage stability of the paste in the form of a paste by adding a surfactant to the starch paste. However, in the case where the storage stability of the starch paste solution was improved by adding a surfactant, the paper strength effect inherently possessed by starch was reduced, and the one in which the storage stability and the paper strength effect were compatible was still found. It has not been. In addition, studies have been made on the graft polymerization of acrylamide to starch, but when the blending ratio of starch is high, it cannot be said that the storage stability of the starch paste solution and the paper strength effect are also compatible. However, the above problems have not been solved.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a papermaking additive which has a long-term storage stability in the state of a starch paste solution and which can maintain the excellent paper strength enhancing effect inherent to starch. The purpose was to.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a starch-containing solution containing a phosphate group was added to a poly (meth) acrylamide containing a phosphate group. They have found that a water-soluble or water-dispersible starch paste solution obtained by mixing derivatives can solve the above-mentioned problems, and have completed the present invention.

That is, the present invention provides a papermaking additive comprising a mixed solution containing (A) a starch containing a phosphate group and (B) a poly (meth) acrylamide derivative containing a phosphate group. And papermaking after adding the papermaking additive to a pulp slurry.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION (A) Starches containing a phosphate group include those originally containing a phosphate group, such as potato starch, or raw starch such as wheat, rice, corn, tapioca, etc. Dextrin or urea phosphate modified starch such as oxidized starch into which a phosphate group is introduced can be used. In the present invention, among these (A) starches containing a phosphate group, viscosity (viscosity measured immediately at 25 ° C. after gelatinization after cooling to a concentration of 10% by weight).
Is preferably 100 cps or more from the viewpoint of the paper strength enhancing effect. It is preferable to use one having a viscosity of 20,000 cps or less from the viewpoint of workability when a mixed solution mixed with (B) poly (meth) acrylamide containing a phosphate group is sent to a pulp slurry.

[0008] The (B) poly (meth) acrylamide derivative containing a phosphate group is a polymer obtained by polymerizing (meth) acrylamide as a main component, and the phosphate group is contained in the polymer. Refers to those contained. The content of the monomeric unit having a phosphate group in such a polymer is 1 mol% with respect to the total mole of the monomers constituting the polymer.
It is preferable that the amount be not less than about in order to improve the storage stability after mixing with (A) a starch containing a phosphate group. In consideration of the paper strength effect, the content is preferably about 20 mol% or less.

(B) The method for producing the poly (meth) acrylamide derivative containing a phosphate group is not particularly limited. For example, a method of introducing a phosphate group into a poly (meth) acrylamide derivative by a modification method appropriately selected, And a method of copolymerizing (meth) acrylamide and a phosphoric acid group-containing monomer. A method of copolymerizing (meth) acrylamide and a phosphoric acid group-containing monomer is preferable from the viewpoint of easy introduction of a phosphoric acid group. Hereinafter, a method of copolymerizing (meth) acrylamide and a phosphoric acid group-containing monomer will be described.

[0010] (Meth) acrylamide refers to acrylamide and / or methacrylamide, which can be used alone or in combination. However, from the viewpoint of economy, acrylamide is preferably used alone.

Specific examples of the phosphoric acid group-containing monomer include polyethylene glycol (meth) acrylate phosphate, 2-((diethoxyphosphyl) oxy) ethyl (meth) acrylate, and bis ((meth) acryloyloxyethyl). ) Hydrogen phosphate, mono (2-
(Meth) acryloyloxyethyl) acid phosphate, diphenyl-2- (meth) acryloyloxyethyl phosphate, 2-hydroxyethyl (meth) acryloylphosphonic acid, 2- (meth) acrylamide-2
-Methylpropanephosphonic acid and alkali metal salts thereof.

When (meth) acrylamide and a phosphoric acid group-containing monomer are copolymerized, the proportion of (meth) acrylamide is usually from 80 to 99 to the total mole of the monomer.
Mol%, and about 1 to 20 mol% of a phosphoric acid group-containing monomer.

The (B) phosphoric acid group-containing poly (meth) acrylamide derivative of the present invention includes, in addition to the (meth) acrylamide and the phosphoric acid group-containing monomer,
Any copolymer of an anionic monomer other than the phosphoric acid group-containing monomer, a cationic monomer, and other copolymerizable monomers can be used as appropriate.

The anionic monomers other than the phosphoric acid group-containing monomer include α, β-unsaturated carboxylic acids and / or salts thereof, for example, monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid; Dicarboxylic acids such as acid, fumaric acid, itaconic acid, muconic acid and citraconic acid; and salts of these various organic acids such as sodium salt and potassium salt. Α, β-unsaturated sulfonic acid and / or
Or a salt thereof, for example, vinyl sulfonic acid, styrene sulfonic acid, methallyl sulfonic acid, 2-acrylamide-2
Organic sulfonic acids such as -methylpropanesulfonic acid; or their sodium and potassium salts.
The use amount of these anionic monomers is preferably about 0 to 10 mol% based on the total moles of the monomers. If it exceeds 10 mol%, the effect of improving the stability of the liquid mixed with the starch is not sufficient, probably because the properties of the phosphate groups are hindered.

The cationic monomers include (C) N,
Tertiary amino group-containing monomers such as N-dialkylaminoalkyl (meth) acrylamide and / or N, N-dialkylaminoalkyl (meth) acrylate, for example, N, N-dimethylaminoethyl (meth) acrylate, N , N-Diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth)
Acrylamide and the like; inorganic or organic acid salts thereof such as hydrochloric acid, sulfuric acid and acetic acid, or methyl chloride;
Examples include quaternary ammonium salt-containing monomers obtained by reaction with quaternizing agents such as benzyl chloride, dimethyl sulfate, and epichlorohydrin. By using these cationic monomers, a higher paper strength effect can be imparted when the papermaking pH is used as a paper strength enhancer for the production of paper having a neutral or weakly acidic papermaking pH. The amount of the cationic monomer used is preferably from 0 to 15 mol% based on the total number of moles of the monomers constituting the polymer. 15 mol%
No further improvement in paper strength is observed even when used in excess, and it is not economical.

Other copolymerizable monomers include:
There are a crosslinkable monomer, a chain transfer substituent and the like. Examples of the crosslinkable monomer include bifunctional monomers such as ethylene glycol di (meth) acrylate, diallylamine, and N-methylolacrylamide; trifunctional monomers such as triallyl isocyanate and N, N-diallylacrylamide; Examples include tetrafunctional monomers such as allyloxyethane. Examples of the monomer having a chain transfer substituent include allyl (meth) acrylate, diethylene glycol mono (meth) acrylate, and dimethylacrylamide. When a crosslinkable monomer, a monomer having a chain transfer substituent, or the like is used, the amount used is generally about 5 mol% or less, preferably 2 mol% or less, based on the total mol of the monomers. If it exceeds 5 mol%, the obtained copolymer becomes gel-like, which is not preferable.

Other copolymerizable monomers include, for example, N-substituted (meth) acrylamides such as t-octylacrylamide, and anionic monomers such as (meth) acrylic acid and maleic acid, and alcohols. Esters, styrene, α-methylstyrene, vinyl toluene, acrylonitrile, methyl vinyl ether, isopropylacrylamide, vinyl acetate, α-olefin and the like can be mentioned. The use amount of these other monomers is preferably about 30 mol% or less based on the total molar amount of the monomers. 3
If it exceeds 0 mol%, it is difficult to obtain a paper having a sufficient paper strength effect.

It is to be noted that anionic monomers other than the phosphoric acid group-containing monomer, cationic monomers, and other copolymerizable monomers are copolymerized to form a poly (B) containing a phosphoric acid group. Even when the (meth) acrylamide derivative is used, the amount of the phosphoric acid group-containing monomer to be used is about 1 to 20 mol% based on the total mole of the monomer components constituting the polymer. Further, in order to obtain a desired paper strength improving effect, the amount of (meth) acrylamide used is preferably 50 mol% or more based on the total mol of the monomer components constituting the polymer.

Various methods known in the art can be employed to obtain the (B) poly (meth) acrylamide derivative containing a phosphoric acid group of the present invention by copolymerizing the monomer. For example, a predetermined amount of the monomer and water are charged into a predetermined reaction vessel, and redox polymerization in the form of a persulfate such as potassium persulfate or ammonium persulfate, or a combination thereof with a reducing agent such as sodium hydrogen sulfite. An ordinary radical polymerization initiator such as an initiator or an azo initiator is added, and the mixture is heated with stirring to obtain the aqueous solution of the poly (meth) acrylamide derivative (B) containing a phosphate group of the present invention. .

The weight average molecular weight of the poly (meth) acrylamide derivative (B) containing a phosphate group of the present invention is preferably 100,000 or more in order to obtain a desired paper strength effect.
The weight average molecular weight is such that the aqueous solution does not become highly viscous (A)
From the viewpoint of productivity at the time of mixing with a starch containing a phosphate group, the content is preferably 5,000,000 or less.

The mixing ratio of (A) the starch containing a phosphate group and (B) the poly (meth) acrylamide derivative containing a phosphate group improves the storage stability and paper strength of the mixed solution. In addition, the determination is made with sufficient consideration so as to maintain the characteristics of starches, such as good re-dispersibility of paper reuse and low cost. Normally,
(A) starch containing phosphate group 50 to 50%
It is preferable to mix (B) a poly (meth) acrylamide derivative containing a phosphate group at a ratio of 2 to 50% by weight with respect to about 98% by weight. In particular, from the viewpoint of storage stability of the obtained mixed solution, the content of the poly (meth) acrylamide derivative (B) containing a phosphate group is preferably 5% by weight or more.

(A) starch containing a phosphate group and (B)
As a method for mixing the poly (meth) acrylamide derivative containing a phosphate group, any method can be adopted as long as a uniform mixed state is achieved. For example, there is a method in which an aqueous solution of gelatinized (A) starch containing a phosphate group and (B) an aqueous solution of a poly (meth) acrylamide derivative containing a phosphate group are mixed in a container having a stirring device. Alternatively, mixing may be performed using a line mixer or the like instead of such a container. Further, an aqueous solution of (A) a starch containing a phosphate group and (B) an aqueous solution of a poly (meth) acrylamide derivative containing a phosphate group before gelatinization are mixed in advance, and the mixture is gelatinized. By doing so, the mixed solution of the present invention can be obtained.

The viscosity of the mixed solution is not particularly limited, but the viscosity of the aqueous solution or the aqueous dispersion at which the concentration of the mixed solution becomes 10% by weight, measured at 25 ° C., is about 100 cps or more. Is preferred in view of Also 20000
Those showing about cps or less are preferable in that the storage stability of the mixed solution is excellent. The viscosity of the mixture is determined by a combination of (A) the viscosity of the starch paste containing phosphate groups and (B) the viscosity of the aqueous solution of the poly (meth) acrylamide derivative containing phosphate groups. The viscosity of the mixed solution is appropriately adjusted at the time of preparing the mixed solution so as to fall within the above range.

The method for producing paper or paperboard of the present invention is characterized in that the pulp slurry contains (A) a starch containing a phosphate group and (B) a poly (meth) acrylamide derivative containing a phosphate group. It is characterized in that papermaking is performed after adding a papermaking additive comprising a liquid as a paper strength enhancer, except that the specific papermaking additive of the present invention is used as the paper strength enhancer. The same conditions as in the method of producing paper or paperboard can be employed.

That is, the paper strength enhancer is usually added at a usage ratio of about 0.1 to 3% by weight (solid content) based on the pulp solid content. The timing of adding the paper strength enhancer can be appropriately set, and the pH of the papermaking system can be applied over a wide range from an acidic range to an alkaline range. Further, the type of pulp and the type of papermaking white water only need to be appropriately determined according to the papermaking conditions, and a sizing agent, a fixing agent, a filler and the like can be appropriately compounded and added.

[0025]

The papermaking additive of the present invention has a high paper strength enhancing effect inherent to starch and also has a long-term storage stability.

[0026]

The present invention will now be described more specifically with reference to examples and comparative examples. Unless otherwise specified, parts and% are based on weight.

Production Example 1 A flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube was charged with 89.0 parts of acrylamide, 900 parts of ion-exchanged water, and mono (2-methacryloyloxyethyl) acid phosphate 11.0 parts. And 1 part of isopropyl alcohol, and replaced with air in the reaction system through nitrogen gas. The mixture was heated to 70 ° C. under stirring, 1 part of an azo-based initiator V-50 manufactured by Wako Pure Chemical Industries, Ltd. was added as a polymerization initiator, polymerization was performed at 85 to 90 ° C. for 180 minutes, and then cooled to room temperature. , Solid content 10.3%, viscosity (25 ° C) 1800
An aqueous solution of cps anionic polyacrylamide derivative was obtained.

Production Examples 2 to 8 In Production Example 1, at least one of the kind of the monomer component and the amount used was changed as shown in Table 1, and the amount of the initiator was changed so as to obtain a desired viscosity. Otherwise in the same manner as in Production Example 1, an anionic polyacrylamide derivative aqueous solution was obtained. Table 1 shows the property values of the obtained aqueous solutions.
Shown in

[0029]

[Table 1]

The abbreviations in Table 1 are: AM: acrylamide, PM: mono (2-methacryloyloxyethyl) acid phosphate, AA: acrylic acid, AN:
Acrylonitrile, IA: Itaconic acid.

Production Example 9 In a flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 77.2 parts of acrylamide, 900 parts of ion-exchanged water, and dimethylaminopropylacrylamide were added.
5 parts, and 15.2 parts of mono (2-methacryloyloxyethyl) acid phosphate were charged, and the pH was adjusted using sulfuric acid.
Was adjusted to 4 to 3, and oxygen in all reaction systems was removed through nitrogen gas. The mixture was heated to 60 ° C. with stirring, 0.21 part of ammonium persulfate and 0.09 part of sodium bisulfite were added as polymerization initiators, and polymerization was carried out at 85 ° C. for 120 minutes. %, An aqueous solution of an amphoteric polyacrylamide derivative having a viscosity (25 ° C.) of 6900 cps was obtained.

Production Examples 10 to 12 In Production Example 9, at least one of the kind of the monomer component and the amount used was changed as shown in Table 2, and the amount of the initiator was changed so as to obtain a desired viscosity. Otherwise in the same manner as in Production Example 9, an amphoteric polyacrylamide derivative aqueous solution was obtained. Table 2 also shows the property values of the obtained aqueous solutions.

[0033]

[Table 2]

In Table 2, AP: dimethylaminopropyl acrylamide, DM: dimethylaminoethyl methacrylate are shown. Others are the same as Table 1.

Production Example 13 860 parts of ion-exchanged water and 140 parts of urea phosphate ester starch (Oji Ace P340, manufactured by Oji Cornstarch Co., Ltd.) were placed in a flask equipped with a stirrer, thermometer, and reflux condenser, and stirred. The mixture was heated below and maintained at 85 to 90 ° C. for 1 hour to perform gelatinization. After cooling, pH 4 ~ with 10% sulfuric acid
It was adjusted to 5 and taken out. Solids concentration 13.2
% And a viscosity (25 ° C.) of 2000 cps to obtain a urea phosphate starch paste solution.

Production Examples 14 and 15 The same operation as in Production Example 13 was carried out except that the types of starch were changed as shown in Table 3 and the solid content concentration of the size liquid was adjusted as shown in Table 3. To obtain a starch paste solution. Table 3 shows the properties of the obtained starch paste solution.

[0037]

[Table 3]

Example 1 In a beaker equipped with a stirrer, 125 parts of the urea phosphate starch paste solution of Production Example 13, 40 parts of the aqueous solution of anionic polyacrylamide derivative of Production Example 1, and 35 parts of deionized water were weighed, and the contents were measured. The mixture was stirred until the mixture became uniform, and the urea phosphate starch / anionic polyacrylamide was mixed at a mixing ratio of 80/20 (weight of solid content) and the solid concentration was 10.1
%, And a mixed solution having a viscosity (25 ° C.) of 1550 cps was obtained. The mixture was homogeneously cloudy and viscous.

Examples 2 to 10 and Comparative Examples 1 to 6 In Example 1, the types of the starch paste solution and the aqueous solution of the polyacrylamide derivative were changed as shown in Table 4,
Other than adjusting the amount used so that the mixing ratio (solid content weight) and the solid content concentration of the polyacrylamide derivative are as shown in Table 4,
The same operation as in Example 1 was performed to obtain a mixed solution containing starch and a polyacrylamide derivative. Table 4 shows the properties of the obtained mixed solution.

[0040]

[Table 4]

(Evaluation 1: Storage stability of mixed solution) Production Example 1
The starch paste obtained in 3 to 15, the starch paste obtained in Examples 1 to 10 and the mixed liquid containing the polyacrylamide derivative obtained in Comparative Examples 1 to 6 were allowed to stand at 20 ° C for 30 days. The change in the state was visually observed. Table 5 shows the results.

[0042]

[Table 5]

(Manufacture of paper 1) BKP was beaten with a Niagara beater to obtain Canadian Standard Free.
Pulp adjusted to 550 ml of Ness (CSF)
After adding sodium carbonate as an H adjuster, a sulfuric acid band was further added to 1.0% with respect to pulp, and then a paper strength enhancer shown in Table 6 was added with 0.5% to pulp, followed by stirring and uniform mixing. . The obtained pulp slurry (pH 6.5) was diluted to 0.5%, and the basis weight was 1 using a tappi sheet machine.
The paper was made to be 00 g / cm ² and press-dewatered at 5 kg / m ² for 2 minutes. Then, it is dried at 100 ° C. for 4 minutes in a rotary dryer, and dried at 20 ° C. and 65% R.C. H. For 24 hours. In addition, the same papermaking was performed on the above-mentioned (Evaluation 1: long-term stability of the mixture), which was stored for 15 days after mixing the mixture of starch and the polyacrylamide derivative.

The T-peel strength (g / cm) of the paper obtained in Paper Production 1 was measured. Table 6 shows the results.

(T-peel strength) Tappi No.
It measured according to 19-m.

[0046]

[Table 6]

(Manufacture of paper 2)
Manufacture of paper except that sodium carbonate was not added as a modifier, calcium carbonate was added to pulp at 20% (calcium ion concentration in pulp slurry was 100 ppm), and those shown in Table 7 were used as paper strength agents. Paper was made in the same manner as in No. 1.

The breaking length (km) of the paper obtained in Paper Production 2 was measured. Table 7 shows the results.

Breaking length: A method for testing the tensile strength of paper and paperboard based on JIS P8113.

[0050]

[Table 7]

(Manufacture of paper 3) Used corrugated paper and used magazine paper were mixed at a weight ratio of 1: 1 and beaten with a Niagara beater, Canadian Standard Freeness (CSF). After adding 2% of the sulfuric acid band to the pulp adjusted to 420 ml, the paper strength enhancer shown in Table 8 with respect to the pulp was added by 0.5%, stirred and uniformly mixed. The resulting pulp slurry (pH 5.6, calcium ion concentration 28
0 ppm) to 0.5%, and the paper is made with a tappy sheet machine to a basis weight of 160 g / cm ^2, and 5 kg
/ M ² for 2 minutes. Next, 1
Dry at 10 ° C for 4 minutes, 2 ° C, 65% R. H. For 24 hours.

The specific burst strength (kPa) of the paper obtained in Paper Production 3 was measured. Table 8 shows the results.

Specific burst strength: A method for testing the burst strength of paper and paperboard based on JIS P8112 using a Mullen low-pressure tester.

[0054]

[Table 8]

Claims (5)

[Claims] 1. A papermaking additive comprising a mixed solution containing (A) a starch group containing a phosphate group and (B) a poly (meth) acrylamide derivative containing a phosphate group. 2. The solid content ratio of (A) a starch group containing a phosphate group to (B) a poly (meth) acrylamide derivative containing a phosphate group is (A) 50 to 98% by weight, B) 50 to 2% by weight of the papermaking additive according to claim 1. 3. The viscosity (25 ° C.) at a concentration of 10% by weight of the mixture is 100 to 20,000 cps.
Or the papermaking additive according to 2. 4. (A) Poly (meth) containing a phosphate group
The papermaking additive according to claim 1, 2 or 3, wherein the acrylamide derivative contains 1 to 20 mol% of a monomer structural unit having a phosphoric acid group based on the total molar amount of the monomer. 5. A method for producing paper or paperboard, comprising adding the papermaking additive according to claim 1 to a pulp slurry and then making the paper.