JP2790497B2 - Papermaking additives - Google Patents

Description

The present invention relates to a papermaking additive. More specifically, under neutral conditions drainage improving action and filler,
The present invention relates to an amphoteric polymer additive for papermaking that enables additives such as a sizing agent to be uniformly retained in paper at a high yield.

[Related Art] In recent years, neutral papermaking has been performed in place of conventional acidic papermaking. The advantages of neutral papermaking include improved paper durability, reduced machine corrosion, use of inexpensive calcium carbonate for filler, and closed system.

On the other hand, there has been a problem in that the conventional drainage / retention agent used in acidic papermaking has no effect or insufficient effect by using neutral papermaking.

In order to solve these problems, a cationized polyacrylamide obtained by subjecting polyacrylamide to a Mannich reaction, a homopolymer of a polymerizable monomer containing a cationized starch, a tertiary amino group or a quaternary ammonium base, or a nonionic polymer A cationic polymer such as a copolymer with a hydrophilic monomer, polyvinylamine, polyallylamine, or polyethyleneimine is used.

More recently, amphoteric products such as an Annich reaction product of an acrylic acid-acrylamide copolymer, a copolymer of a polymerizable monomer containing a tertiary amino group or a quaternary ammonium group and acrylic acid, and a Hoffman decomposition product of polyacrylamide have been proposed. Polymers are being used.

[Problems to be Solved by the Invention] These cationic or amphoteric polymers are used as a drainage improver under neutral conditions and as a retention agent such as filling and sizing agents. There is a problem of insufficient or uneven retention in the paper.

[Means for Solving the Problems] The present inventors have intensively studied to solve these problems and completed the present invention. That is, the present invention (Wherein, n is a positive integer, R ₁ , R ₂ , and R ₃ are each a hydrogen atom or an alkyl group. R ₄ is a hydrogen atom, an alkyl group, or a hydroxylalkyl group.) In the amphoteric polyelectrolyte containing as an essential component, some or all of the amino groups are neutralized with an acid, the cation equivalent value (Cv) is 1.50 to 15.0 meg / g, and the anion equivalent value (Av) is 0.1 to 7.0meg / g, Cv / Av 0.2-45.0
And a paper additive.

The method for producing the papermaking additive in the present invention is not particularly limited, but the following method is preferred.

A salt of an aminoalkyl ester monomer of a reaction product of a vinyl carboxylic acid monomer and an alkylene imine, and a vinyl carboxylic acid monomer copolymerized with the salt.

The vinyl carboxylic acid monomer is polymerized, the resulting vinyl carboxylic acid polymer is reacted with an alkylene imine to aminoalkylate, and then neutralized with an acid.

A salt of an aminoalkyl ester monomer of a reaction product of a vinyl carboxylic acid monomer and an alkylene imine, and water and oil in the presence of a vinyl carboxylic acid monomer and water, a surfactant and a hydrophobic organic solvent. After emulsifying in a mold, copolymerization is carried out.

After emulsifying the vinyl carboxylic acid in water, a water-in-oil type in the presence of water, a surfactant and a hydrophobic organic solvent, the alkylene imine is reacted with the vinyl carboxylic acid polymer emulsion obtained by polymerization to obtain an aminoalkyl. And then neutralized with acid.

In addition, in the papermaking additive of the present invention, a nonionic monomer may be copolymerized for the purpose of adjusting the molecular weight or ion equivalent.

As the vinyl carboxylic acid monomer used here, acrylic acid, methacrylic acid or their ammonium salts, sodium salts, potassium salts and the like are preferable.

In particular, when synthesizing a papermaking additive using the above method, the neutralization ratio of the vinyl-based anionic monomer is in the range of 5 to 100 mol%, preferably 20 to 95 mol%.

Non-ionic monomers include (meth) acrylamide,
N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylamide, hydroxypropyl (meth) acrylamide, acrylonitrile, etc. Is used.

As the alkylene imine, 1,2-alkylene imine (aziridine) is preferable, and among them, 1,2-propylene imine and ethylene imine are particularly preferable because of their availability and relatively low cost. Other substituted 1,2-aziridines can be used if desired.

The polymerization in the above-mentioned and methods can be carried out by a usual method using a usual peroxide-based, azo-based, or redox-based polymerization initiator.

Examples of the peroxide-based initiator include ammonium persulfate, potassium persulfate, hydrogen peroxide, cumene hydroperoxide, and the like. Examples of the azo-based initiator include azobisisobutyronitrile and 2,2'-azobis (2 -Amidinopropane) dihydrochloride, 2,2'-azobis (2,4-dimethylvaleronitrile), 4,4'-azobis (4-cyanopentanoic acid) and the like. Redox initiators include peroxide initiators and formaldehyde sodium sulfoxylate, thioglycolic acid, L-ascorbic acid, dimethylaminopropionitrile, sodium bisulfite, β-mercaptoethanol, and divalent iron salts And the like. Further, a peroxide initiator or a redox initiator and an azo initiator can be used in combination.

Isopropyl alcohol, erythorbic acid, 2
-A known chain transfer agent such as mercaptoethanol may be added.

Examples of the surfactant used for the water-in-oil type emulsification in the above method include ordinary nonionic surfactants. For example, sorbitan monooleate, sorbitan monostearate, sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, glycerol monooleate and the like can be mentioned. These emergency ionic surfactants can be used alone or in a mixture.

Examples of the hydrophobic organic solvent include hydrophobic aliphatic or aromatic hydrocarbons, vegetable or animal oils, and modified oils thereof. Typical examples are normal paraffin, isoparaffin, cyclohexane, naphthene,
Toluene, xylene, kerosene, mineral oil, kerosene and the like.

The total amount of the salt of the aminoalkyl ester monomer and the total amount of the vinyl anionic monomer and the nonionic monomer in the method of the above, the total amount of the vinyl anionic monomer and the nonionic monomer in the method of the water The concentration for
80% by weight is desirable. The concentration of the surfactant used in the hydrophobic organic solvent is preferably 5 to 30% by weight. Also,
The ratio of hydrophobic organic solvent to water is 1:10 to 10: 1, preferably
1: 5 to 3: 1.

The polymerization concentration is preferably about 5 to 80% by weight. If it is less than 5% by weight, the productivity is low, so that it is not preferable. If it exceeds 80% by weight, a large amount of heat of polymerization is generated and the temperature of the system becomes too high. The polymerization temperature is preferably from 10 to 120 ° C. The polymerization time varies depending on the concentration of the monomer, the polymerization temperature, or the desired degree of polymerization, but is about 10 minutes to 10 hours, and more preferably about 1 to 7 hours.

The aminoalkylation reaction in the above method can be performed by reacting an alkyleneimine with a vinyl carboxylic acid polymer.

In this case, if necessary, a divalent metal ion is added to the vinyl carboxylic acid polymer in advance to partially form a chelate with the carboxylic acid, followed by aminoalkylation. Alternatively, a method may be used in which an alkylalkylamine and a neutralizing acid are alternately divided and added to the vinyl carboxylic acid copolymer to carry out aminoalkylation.

The aminoalkylation reaction is carried out at a temperature of preferably 65 ° C. or lower, and more preferably 10 to 55 ° C. If the reaction temperature exceeds 65 ° C., gelation occurs during the reaction, or the product becomes cloudy and insolubles are formed. Conversely, if the temperature is lower than 10 ° C., the reaction time becomes unlimitedly long and has no meaning.

The neutralization of the aminoalkyl group is carried out at 50 to 150 mol% with respect to the added alkyleneimine, and is carried out at one time or at the time of aminoalkylation. The neutralizing acid is not particularly limited, but hydrochloric acid, nitric acid, sulfuric acid and the like are preferable.

When producing the papermaking additive of the present invention, the cation equivalent value Cv is 1.0 to 15.0 meg / g, and the anion equivalent value Av is 0.1 to
7.0 meg / g, so that the Cv / Av is 0.2 to 45.0, the amount of a salt of a vinyl carboxylic acid monomer and an aminoalkyl ester monomer, or the amount of a vinyl carboxylic acid polymer and an alkyleneimine, or It is necessary to determine the amount of nonionic monomer. The cation equivalent value and the anion equivalent value referred to herein are based on the active ingredient obtained by removing the amounts of the neutralizing acid and the surfactant from the solid content of the sample.

In the papermaking additive of the present invention, when the Cv / Av is 20 or less, the filler is particularly excellent in retention.However, when the Cv / Av is less than 0.2, the interaction with the pulp is weak, the drainage is reduced, and the filler retention is further reduced. Is also non-uniform, which is undesirable. If Cv / Av exceeds 20, excellent drainage and retention of sizing agent are obtained. However, if Cv / Av exceeds 45, the cohesive strength of the filler is reduced and the yield is also undesirably reduced.

The 10% aqueous solution viscosity of the papermaking essential agent of the present invention is 50 to 100,000 cps, preferably 100 to 20,000 cps (pH 3.5,2
It is desirable to appropriately set the composition of each monomer, polymerization conditions, and the like so as to obtain (Brookfield viscosity at 5 ° C.).

The pulp to which the papermaking additive of the present invention can be applied can be any conventional pulp, for example, ground pulp, thermomechanical pulp, sulfite pulp, semi-chemical pulp, kraft pulp, various synthetic pulp and those obtained by disintegrating waste paper. . Further, it can be used in combination with various auxiliaries such as a sizing agent, a drainage improver, a retention agent, a slime control agent, an antifoaming agent, a bitch control agent and a pH adjuster.

The amount of the papermaking additive of the present invention to be added to pulp is suitably 0.01 to 0.2% based on dry pulp.

[Operation] By adding the papermaking additive thus obtained to the pulp slurry under neutral conditions, the drainage property is improved, and additives such as fillers and sizing agents are uniformly and at a high yield. It is possible to keep it inside.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto.

(Production of vinyl-based carboxylic acid polymer) Reference Examples 1 to 4 Charge the monomers so as to obtain a finish of 20% by weight based on the composition ratio of the monomers shown in Table 1, and maintain the temperature at 50 ° C after purging with nitrogen. 0.2% sodium for each monomer
Polymerization was carried out for 4 hours by adding by weight to obtain a vinyl carboxylic acid polymer aqueous solution.

(Manufacture of papermaking additive) Reference Example A 167 g of hydrochloride salt of aminoethyl methacrylate obtained from the reaction of methacrylic acid and ethyleneimine and acrylic acid 33
g was prepared so as to have a finish of 20% by weight, and maintained at 50 ° C. after replacement with nitrogen, and 0.2% by weight of 2,2′-azobis (2-amidinopropane) dihydrochloride was added to the monomer. Polymerization was performed for 4 hours to obtain a papermaking additive A of the present invention.

Reference Example B Vinyl carboxylic acid polymer aqueous solution synthesized in Reference Example 1
100 g and 73 g of ion-exchanged water were charged, and while stirring at room temperature, 6.0 g of ethyleneimine was added, and the mixture was reacted at 50 ° C. for 2 hours. Then, 10.1 g of 61% by weight of nitric acid was added and stirred for 30 minutes. Next, 6.0 g of ethyleneimine was further added and reacted for 1 hour, and then 10.1 g of 61% by weight nitric acid was added and stirred for 30 minutes.
An additive B for papermaking of the present invention was obtained.

Reference Examples C to H In Reference Example B, the same procedures were performed except for the conditions shown in Table 2.

Reference Example I Vinyl-based carboxylic acid polymer aqueous solution synthesized in Reference Example 3
After adding 6.6 g of a 40% calcium chloride aqueous solution to 100 g to make the mixture uniform, 4.2 g of ethyleneimine was added with stirring at room temperature, and the mixture was further reacted at 50 ° C. for 4 hours. Thereafter, 10.2 g of 35% by weight hydrochloric acid was added and the mixture was stirred for 30 minutes to obtain the papermaking additive I of the present invention.

Reference Examples J and K In Reference Example B, the same procedure was performed except for the conditions shown in Table-3.

Reference Example L In a four-necked flask equipped with a stirrer, a thermometer, a cooler, a dropping funnel, and a nitrogen gas inlet tube, 100 g of Isopar M (isoparaffin solvent manufactured by Exxon Chemical Co., Ltd.) was placed, and 11.6 g of sorbitan monooleate was dissolved therein. . 80 g of acrylic acid, 20 g of acrylamide, 52.9 g of 28% ammonia water, 33.9 g of ion-exchanged water
g mixture was added slowly to emulsify. After the inside of the system was sufficiently purged with nitrogen, the temperature was raised to 60 ° C, 0.7 g of azobis (dimethylvaleronitrile) was added as a catalyst, and the mixture was heated and stirred for 4 hours while maintaining the temperature at 60 ° C. A coalesced emulsion was obtained.

While maintaining the temperature at 50 ° C., 23.9 g of ethyleneimine was added dropwise and stirred for 30 minutes. Next, 57.4 g of 61% by weight nitric acid aqueous solution
The mixture was added dropwise and stirred for 30 minutes. Next, 76.1 g of ethyleneimine was added dropwise and stirred for 30 minutes. Then, a 61% by weight aqueous nitric acid solution was added to 110.
7 g was added dropwise and stirred for 30 minutes to obtain a papermaking additive L of the present invention.

Reference Example M 111.6 g of Isopar M (isoparaffin solvent manufactured by Exxon Chemical Co., Ltd.) was placed in a four-necked flask equipped with a stirrer, thermometer, cooler, dropping funnel and nitrogen gas inlet tube, and 22.3 g of sorbitan monooleate was added thereto. Melt it. To this, a mixture of 167 g of aminoethyl methacrylate hydrochloride obtained from the reaction of methacrylic acid and ethyleneimine prepared as a monomer aqueous solution, 33 g of acrylic acid, and 135 g of ion-exchanged water was slowly added and emulsified. After the system was sufficiently purged with nitrogen, the temperature was raised to 60 ° C, 0.4 g of 2,2'-azobis (dimethylvaleronitrile) was added as a catalyst, and the mixture was heated and stirred for 8 hours while maintaining the temperature at 60 ° C. Additive M was obtained.

Reference Example N Methacryloyloxyethyltrimethylammonium chloride (4DAM), AAm, and AA were charged at a weight ratio of 4DAM / AAm / AA = 30/60/10 so that the finish became 20% by weight. While keeping the mixture, 2,2'-azobis (2-amidinopropane) dihydrochloride was added at 0.2% by weight based on the monomer to carry out polymerization for 4 hours to obtain an amphoteric polymer aqueous solution of Reference Example N.

Table 4 shows the physical properties of the papermaking additives obtained in Reference Examples A to N.
It was shown to.

In addition, the cation equivalent value and the cation equivalent value shown in Table 4 and the text were determined by the following methods.

(1) Cation equivalent value Take 95 ml of distilled water in a beaker, and convert the active ingredient to 1000 ppm.
5 ml of a sample solution, and add 1% HCl or 1% NaOH to pH 3.
After adjusting to 0, the mixture was stirred for about 1 minute, and then 2 to 3 drops of a toluidine blue indicator solution was added, and the mixture was titrated with N / 400 PVSK (aqueous polyvinyl potassium sulfate). The titration speed is 2 ml per minute,
The point at which the test sample changed color from blue to reddish purple and held for 10 seconds or longer was defined as the end point.

Cation equivalent value (Cv) [meq / g] = (sample titer) [ml]-blank titer [m
l]) × N / 400 Potency of PVSK / 2 The active ingredient is a solid content of the sample excluding the neutralizing acid and the surfactant.

(2) Anion equivalent value 50 ml of distilled water was placed in a beaker, and about 0.3 g of a sample was precisely weighed and added. Titrate with N / 10 NaOH aqueous solution while stirring and read the conductivity. Read the titer corresponding to the last inflection point (point where all acids have been neutralized) out of some inflection points.

Anion equivalent value (Av) [meq / g] = 0.1 x titer of N / 10NaOH x (titration of N / 10NaOH [ml]-amount of neutralized acid in precisely weighed sample [meq]) / in precisely weighed sample [G] Examples 1 to 11 Papermaking was carried out using the papermaking additives obtained in Reference Examples A to I, L and M, and the yield of calcium carbonate and the dispersion of calcium carbonate in the paper. The properties were evaluated and the results shown in Table 5 were obtained.

Comparative Examples 1 to 6 Reference Examples J, K, and N. Papermaking was carried out using the papermaking additives obtained from J, K, and N, a commercially available polyacrylamide Hoffman degradation product and polyethyleneimine, and the yield of calcium carbonate and the calcium carbonate in paper The dispersibility was evaluated, and the results in Table 5 were obtained.

(Papermaking conditions) Papermaking using this test was performed under the following conditions.

Pulp: NBKP, filler: heavy calcium carbonate (commercially available), pulp / filler = 100/30 pH: 9.3, sizing agent: AKD sizing agent (commercially available) 0.2% vs. pulp slurry Addition order: pulp → filler → sizing agent → Papermaking additive of the present invention → papermaking Papermaking: tappy square sheet machine Press: 3.5 kg / cm ² × 2 minutes, drying: drum dryer 11
0 ° C × 150 seconds Weighing: 65 g / m ² (Evaluation method) Calcium carbonate yield: 600
It was determined from the ash content which was heat-treated for 20 minutes at ° C.

Calcium carbonate dispersibility: Paper was made under the above conditions after coloring calcium carbonate with a dye, and the dispersion state was visually evaluated.
Good ○, bad ×.

Stockigt sizing degree: Measured according to JIS, P8122.

Freeness: A papermaking additive was added to 0.3% NBKP pulp rally (pH 7.6) 1 and measured by Canadian Standard Freeness Tester.

(JIS P8121).

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-58-54097 (JP, A) JP-B-48-20240 (JP, B1) JP-B-47-30003 (JP, B1) JP-B-56 95906 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) D21H 11/00-27/42

Claims (1)

(57) [Claims] (1) (In the formula, n is a positive integer, R ₁ , R ₂ , and R ₃ are each a hydrogen atom or an alkyl group. R ₄ is a hydrogen atom, an alkyl group, or a hydroxylalkyl group.) In the amphoteric polyelectrolyte containing as an essential component, some or all of the amino groups are neutralized with an acid, the cation equivalent value (Cv) is 1.0 to 15.0 meg / g, and the anion equivalent value (Av) is 0.1 to 7. A papermaking additive, characterized in that 7.0 meg / g and Cv / Av are in the range of 0.2 to 45.0.