JP3221949B2 - Sizing composition for papermaking - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sizing composition for papermaking, and more particularly to a rosin-dispersed papermaking size in which the dispersed particles have a cationic property and are excellent in effect and stability. It relates to the agent.

[0002]

2. Description of the Related Art Conventionally, in the papermaking industry, for the purpose of water resistance (sizing) of paper, a saponified or dispersed rosin-based sizing agent is fixed in paper as aluminum salt of rosin using aluminum sulfate. Have been.

[0003] In recent years, however, it has become common in the papermaking industry to perform neutral or alkaline papermaking using calcium carbonate as a filler. Also, calcium carbonate as a coating pigment is mixed into papermaking systems through recycling of waste paper or waste paper, and the pH of papermaking becomes neutral or alkaline in many cases.

In such cases, conventional rosin-based sizing agents have only a poor sizing effect and are unusable. Therefore, when the papermaking pH is neutral or alkaline, AKD (alkyl ketene dimer) or ASA (alkenyl succinic anhydride) based sizing agent is used.

[0005]

However, these AKs
The use of D and ASA sizing agents has caused various problems in terms of paper quality such as slipperiness, toner adhesion, and the like, and has completely solved the problem of stains in the paper making process due to the use of these agents. It is hard to say.

[0006] From this point of view, attempts have been made to improve the rosin-based sizing agent, which has been widely used in the papermaking industry, to use it in a neutral pH range. Attempts have been made to obtain cationic rosin-based dispersions for the purpose of improving fixability.

Use of a cationized starch as a dispersant (JP-A-57-135860 and JP-A-56-45950);
Those using a specific polyacrylamide resin (Japanese Unexamined Patent Publication
JP-A-56-169898 and JP-A-3-227481) have been proposed, but sufficient effects have not yet been obtained.

The present inventors have conducted intensive studies to obtain a dispersion of a cationic rosin-based material having excellent effects in the neutral papermaking pH range and excellent dispersion stability. When a grafted cationized starch (hereinafter referred to as a grafted cationic starch) prepared by graft-polymerizing monomers containing (meth) acrylamide to the cationized starch is used, excellent dispersibility is obtained in a neutral pH range. The present inventors have found that a dispersion-type sizing composition of a cationic rosin-based substance having excellent effects can be obtained, and have completed the present invention.

[0009]

SUMMARY OF THE INVENTION In general, the present invention relates to a papermaking sizing composition obtained by emulsifying and dispersing a rosin-based substance with a dispersant, wherein the dispersant is added to a cationic starch. A sizing composition for papermaking, which is a grafted cationic starch prepared by graft polymerization of monomers containing (meth) acrylamide. Hereinafter, the technical configuration of the present invention will be described in detail.

The rosin-based substance used in the paper-making sizing composition of the present invention refers to a rosin-based material which has been processed by various methods in order to impart suitability as a paper-making sizing agent to an unsaturated material. Acid-added rosin, partially esterified product of unsaturated acid-added rosin with alcohols, similarly amidated with amines, aldehyde-modified rosin,
Phenol aldehyde precondensate addition rosin, hydrogenated rosin, esterified rosin and the like and mixtures thereof are included.

That is, the present invention relates to a paper sizing composition obtained by dispersing the above-mentioned modified rosins in water with a specific dispersing agent. It is a modified starch prepared by graft-polymerizing monomers containing (meth) acrylamide, that is, it is composed of a grafted cationic starch.

In preparing the novel dispersants of the present invention, the basis of the graft polymerization is cationized starch. As the cationized starch, various ones can be used. For example, a low-viscosity starch obtained by reacting a cationizing reagent with a starch having a polymerization degree reduced by oxidation or enzyme modification is advantageously used.

The cationized starch used in the present invention will be described in more detail. As the cationized starch, raw starch such as corn, potato, tapioca, sweet potato, wheat, rice, etc. can be used as a primary or secondary cationized starch by known means. Various cationized modified starches having a basic nitrogen atom in a form into which one or more selected from a tertiary amine and a quaternary ammonium group are introduced are used.

For example, as a method for producing a cationized starch containing a quaternary ammonium group, there are a wet method using an aqueous medium and a dry method using a solid / liquid phase reaction, but the wet method is usually employed. Is done. In this method, a cationizing agent comprising a reaction product of a dialkylamine or a trialkylamine and epichlorohydrin is reacted with starch in an aqueous medium in the presence of an alkali, thereby efficiently producing a cationized starch. be able to.

In the present invention, the monomers to be graft-polymerized to the cationized starch need to be monomers containing (meth) acrylamide.
In the present invention, it goes without saying that other copolymerizable monomers can be used in addition to the above-mentioned monomers.

The above-mentioned (meth) acrylamide is an important graft monomer for imparting non-foaming properties and stability of emulsion particles to the prepared dispersant. That is, by using (meth) acrylamide which is a hydrophilic monomer, the grafted cationic starch prepared for the first time becomes a non-foaming and a dispersant excellent in stability of emulsion particles.

In this respect, when the main graft monomer is not water-soluble, a combined use of a surfactant and an organic solvent is required at the time of graft polymerization, so that the resulting grafted cationic starch becomes foamable, and the rosin-based material dispersion Impairs liquid stability.

On the other hand, even when the main monomer is a water-soluble monomer other than (meth) acrylamide, the above-mentioned tendency of foamability is the same, and the stability of the dispersed particles also becomes poor.

The grafted cationic starch of the present invention can be prepared by various methods using the above graft monomer in the presence of the cationized starch. For example, a method using a so-called grafting catalyst such as a cerium salt is one of the methods, but the purpose can be easily achieved by graft-polymerizing the graft monomers using a known polymerization catalyst in the presence of a cationized starch. Is obtained.
The grafted cationic starch as the dispersant of the present invention generally comprises 10 to 95% by weight of the cationized starch, and 5 to 90% by weight of (meth) acrylamide and other monomers.

In the present invention, when the amount of the cationized starch is more than 95% by weight or less than 10% by weight, both of them show insufficient dispersibility, so that a sufficient effect cannot be obtained. The papermaking size composition of the present invention, that is, the papermaking size composition comprising the rosin-based substance and the grafted cationic starch as a dispersant prepared as described above, has a solid content of (1) a rosin-based substance ... 50-99% by weight, preferably 80-97% by weight (2) Grafted cationic starch ... 1-50% by weight, preferably 3-20% by weight; Starch
If the amount is less than 1% by weight, sufficient dispersion stability cannot be obtained, and the size effect is reduced.

The sizing composition for papermaking of the present invention contains the above-mentioned rosin-based material as an essential size component, but other sizing agents, such as hydrocarbons, as long as the effect of the rosin-based material is not impaired. Needless to say, an appropriate amount of resin, ASA, AKD, an oil or fat derivative and the like can be blended.

Further, the sizing composition for papermaking of the present invention comprises:
Although the above grafted cationic starch is used as an essential dispersant, other dispersants such as sodium naphthalenesulfonate formalin condensate, ligninsulfonate, or various surfactants may be used in combination. It goes without saying that you can do it.

[0023]

The present inventors have not sufficiently clarified the reason why the paper sizing composition of the present invention exhibits excellent stability and excellent effects, but presume as follows.

The rosin-based material particles themselves are negatively charged. The grafted cationic starch has hydrophilic and water-retentive polymer chains oriented outward on the cationic starch. Therefore, in the dispersion liquid, the grafted cationic starch having the polymer chains directed to the outside is dispersed on the dispersed particles of the rosin-based substance, thereby stabilizing the particles. -The dispersed particles of the rosin-based substance have cationic properties due to the action of the grafted cationic starch, and are effectively firmly fixed to the negatively charged pulp fibers. From the synergistic effects of the above points, it is considered that excellent results are expressed.

[0025]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but it goes without saying that the present invention is not limited by these Examples. In each of the following examples, unless otherwise specified,% indicates% by weight and part indicates parts by weight.

Production Example 1 285 parts of water was added to 100 parts of the absolute dry matter of an oxidized modified tapioca starch having a paste solution viscosity of 30 cps at 20% 30 ° C., heated at 85 ° C. for 1 hour, cooled, and then cooled at 60 ° C. to 50 parts. % Caustic soda 3.4 parts, glycidyl trimethyl ammonium chloride equivalent to pure content 1
After adding 5.3 parts and reacting at the same temperature for 4 hours, cool and
12 parts of a 5% sulfuric acid aqueous solution was added, and water was further added to make a total amount of 460 parts. The prepared cationized starch had a solid content of 25%, a degree of substitution (DS) of 0.15, and a pH of 4.5. Hereinafter, this is referred to as cationic starch I.

[0027] 40% solution 90 parts of acrylamide in a 25% solution 240 parts of the cationic starch I, 4 parts of di-methylamino-propyl acrylamide, adding 15% aqueous sulfuric acid solution was prepared in pH 4.0, water was added, The total amount was adjusted to 360 parts, and the mixture was brought to 35 ° C., and then 0.8 parts of ammonium persulfate and 0.2 parts of sodium bisulfite dissolved in 10 parts of water were added to carry out polymerization. 3 hours 50
After polymerization at ~ 65 ° C, water was added to make the total amount 400 parts to obtain a 25% solution of the grafted cationic starch I. The viscosity of the obtained solution (25 ° C.) was 340 cps.

Production Example 2 255 parts of water was added to 100 parts of absolute dry matter of the oxidized modified tapioca starch used in Production Example 1, heated at 85 ° C. for 1 hour, cooled, and cooled to 50 ° C.
And 3.4 parts of a 50% sodium hydroxide solution and 29.3 parts of glycidyltrimethylammonium chloride in terms of pure content were added.
After reaction at the same temperature for 5 hours, the mixture was cooled. At 30 ° C., 11 parts of a 15% aqueous sulfuric acid solution was added, and water was further added to make a total amount of 440 parts.
The obtained cationic starch has a solid content of 30% substitution degree (DS) of 0.
3, pH 4.0. This is designated as cationic starch II.

[0029] The 40% aqueous solution 60 parts of acrylamide in a 30% solution 233 parts of cationic starch II, di methyl amino propyl acrylamide 6 parts was added, the pH in 15% aqueous sulfuric acid
After adjusting to 4.0, water was added to bring the total amount to 360 parts, heated to 55 ° C., 1 part of ammonium persulfate dissolved in 10 parts of water, and added.
Polymerization at 0 to 75 ° C. for 1 hour, further dissolving 0.3 part of ammonium persulfate in 10 parts of water, adding 2 hours of polymerization at the same temperature, adding water, and adding the whole amount to 400 parts to grafted cationic starch II. To give a 25% solution. The viscosity of the resulting solution (25 ° C)
It was 550 cps.

Production Example 3 Production Example 1 except that 14.7 parts of glycidyltrimethylammonium chloride in terms of pure content was used, using an oxidized modified corn starch having a 20% paste viscosity (25 ° C.) of 40 cps.
25% solids, degree of substitution (DS) 0.15, pH
A cationic starch of 4.5 was obtained. Hereinafter, this is called cationic starch
III.

To 160 parts of the 25% solution of the cationic starch III, 135 parts of a 40% solution of acrylamide, 6 parts of trimethylaminoethyl acrylate hydrochloride and 65 parts of water were added, and the pH was adjusted to 4.0 with a 15% sulfuric acid solution. Warm to 55 ° C, add 2 parts of ammonium persulfate dissolved in 10 parts of water, polymerize at 70-75 ° C for 1 hour, and further add 0.6 parts of ammonium persulfate in 10 parts of water.
The resulting solution was added to the solution, and the mixture was polymerized at the same temperature for 2 hours, and then water was added to make a total amount of 400 parts to obtain a 25% aqueous solution of grafted cationic starch III having a viscosity (25 ° C.) of 2500 cps.

Production Example 4 The same operation as in Production Example 1 was conducted except that only 100 parts of a 40% aqueous solution of acrylamide was used instead of 90 parts of a 40% aqueous solution of acrylamide and 4 parts of dimethylaminopropylacrylamide in Production Example 1. Thus, a 25% aqueous solution of the grafted cationic starch IV having a viscosity (25 ° C.) of 270 cps was obtained.

Production Example 5 (Production of fumarized rosin) 800 parts of gum rosin having an acid value of 165 were heated and melted, and then heated with stirring. At 135 ° C., 30 parts of formalin were added over 20 minutes, and then 1 hour was required. After heating to 170 ° C., 48 parts of fumaric acid was added, and the mixture was reacted at 180 to 200 ° C. for 4.5 hours and taken out to obtain a fumaric acid-added modified rosin (hereinafter referred to as modified rosin A). The resulting modified rosin A has an acid value
200 and softening point 101 ° C.

Production Example 6 (Production of Triethanolamine Esterified and Maleated Rosin) 750 parts of gum rosin having an acid value of 165 was melted by heating, and then heated while stirring. At 180 ° C., 60 parts of triethanolamine was added for 10 minutes. After adding over 1 hour, the temperature was raised to 200 ° C. over 1 hour, and after reacting at 200 ± 5 ° C. for 2 hours, maleic anhydride 67.
Five parts were added over 10 minutes, and the mixture was further reacted at 200 ± 5 ° C. for 1 hour and 30 minutes, and taken out to obtain triethanolamine esterified maleic acid-modified rosin (hereinafter referred to as modified rosin B). The resulting modified rosin had an acid value of 124 and a softening point of 90 ° C.

Production Example 7 (Production of Glycerin Esterified and Maleated Rosin) Glycerin (24 parts) was added to 500 parts of a gum rosin having an acid value of 165, and the mixture was reacted at 250 ± 5 ° C. for 5 hours in a nitrogen stream. ° C
In, 45 parts of maleic anhydride was added over 10 minutes,
After further reacting at 200 ± 5 ° C. for 1 hour and 30 minutes, the reaction mixture was taken out to obtain glycerin-esterified maleic acid-modified rosin (hereinafter referred to as modified rosin C). The resulting modified rosin had an acid value of 125 and a softening point of 97 ° C.

[0036] 40% aqueous solution of 90 parts of Comparative Production Example 1 acrylamide, 4 parts of di-methylamino-propyl acrylamide, a mixture of 90 parts of water, pH with sulfuric acid
Was adjusted to 4.0, a solution prepared by dissolving 1.0 part of ammonium persulfate and 1.0 part of sodium bisulfite in 5 parts of water at 30 ° C. was added, and polymerization was started.The polymerization was maintained at an internal temperature of 65 to 70 ° C. for 3 hours. In addition, the total amount was 200 parts, and a polymer I having a concentration of 20% and a viscosity (25 ° C.) of 120 cps was obtained.

Comparative Production Example 2 100 parts of a 40% aqueous solution of acrylamide and 85 parts of water were mixed,
After adjusting the pH to 4.0 with sulfuric acid and heating to 35 ° C, 1.0 part of ammonium persulfate and 0.3 part of sodium bisulfite dissolved in 5 parts of water were added, and polymerization was started. Water was added after the heat-remaining polymerization, and the total amount was adjusted to 200 parts to obtain a polymer II having a concentration of 20% and a viscosity (25 ° C.) of 450 cps.

Comparative Production Example 3 90 parts of a 40% aqueous solution of acrylamide, 4 parts of trimethylaminoethyl acrylate hydrochloride and 90 parts of water were mixed, the pH was adjusted to 4.0 with sulfuric acid, and 1.0 part of ammonium persulfate at 30 ° C.
A solution prepared by dissolving 1.0 part of sodium bisulfite in 5 parts of water was added, and polymerization was started. After the polymerization was carried out at an internal temperature of 65 to 70 ° C. for 3 hours, water was added to make the total amount 200 parts, the concentration was 20%, and the viscosity ( 25 ° C) 450 c
Polymer III having ps was obtained.

Example 1 Fifty parts of the modified rosin A of Production Example 5 was heated and melted at 150 ° C.
To 20 parts of a 25% solution of the grafted cationic starch I of Production Example 1, 2.5 parts of polyoxyethylene nonylphenyl ether sulfate ammonium salt and 17.5 parts of water were mixed and mixed at 85 ° C.
The heated solution was added with vigorous stirring to form a water-in-oil emulsion, and then hot water was added to transfer the mixture into an oil-in-water emulsion. A sizing agent for papermaking was obtained.

Example 2 The procedure of Example 1 was repeated except that the modified rosin A was replaced with the modified rosin B of Production Example 6 and that 2 parts of polyoxyethylene nonylphenyl ether sulfate ammonium were used.
In the same manner as in the above, a sizing agent for papermaking having a chaotic rosin-based dispersion type of the present invention having a solid content of 35% was obtained.

Example 3 The same procedure as in Example 2 was carried out except that the modified rosin C of Preparation Example 7 was used instead of the modified rosin B, and the cationic rosin-based dispersion type papermaking of the present invention having a solid content of 35% was used. A sizing agent was obtained.

Example 4 The procedure of Example 2 was repeated, except that the grafted cationic starch I was replaced by a 25% solution of the grafted cationic starch II of Preparation Example 2. The cationic rosin-based dispersion type paper sizing agent of the present invention was obtained.

Example 5 The procedure of Example 2 was repeated, except that a 25% solution of the grafted cationic starch III of Preparation Example 3 was used instead of the grafted cationic starch I. The cationic rosin-based dispersion type paper sizing agent of the present invention was obtained.

Example 6 A cationic rosin dispersion having a solids content of 35% was prepared in the same manner as in Example 2 except that the grafted cationic starch IV of Preparation Example 4 was used instead of the grafted cationic starch I. A sizing agent for type papermaking was obtained.

Example 7 70 parts of the modified rosin A of Production Example 4 was dissolved in 70 parts of toluene, and a 25% solution of the grafted cationic starch I of Production Example 1 was added.
Part, water 180 parts dissolved lignin sulfonate sodium 1.4 parts was added, and after stirring and emulsification, 300 kg / cm with a high-pressure homogenizer.
After emulsifying by passing through 3 times by applying the pressure of ² , the toluene is distilled off under reduced pressure, water is added to adjust the concentration, and the cationic rosin dispersion type of the present invention having a solid content of 35% is used. A sizing agent for papermaking was obtained.

Comparative Examples 1 to 3 The procedure of Example 1 was repeated except that 25 parts of a 20% aqueous solution of the polymers I, II and III of Comparative Production Examples 1 to 3 was used instead of the grafted cationic starch I of Example 1. The same operation was performed. The resulting dispersions were each adjusted to a solid content of 35% by adding water.

Comparative Examples 4 to 6 Example 2 was repeated except that 17 parts of a 30% aqueous solution of the cationized starches I, II and III of Preparation Examples 1 to 3 was used instead of the grafted cationic starch I of Example 2. Operate in the same manner as
A cationic rosin-based dispersion-type papermaking sizing composition for comparison of 35% was obtained.

Comparative Examples 7 and 8 Instead of the grafted cationic starch of Example 1, 12 parts of a 25% aqueous solution of the cationic starch of Production Example 1 and 10 parts of a 20% aqueous solution of the polymers of Comparative Production Examples 1 and 2 were used. except,
The same operation as in Example 1 was performed. The resulting dispersions were adjusted to 35% solids by adding water.

Performance Evaluation Each of the sizing compositions of Examples 1 to 6 and Comparative Examples 1 to 8 was evaluated for the properties of the dispersion and the sizing effect when applied as a paper-making sizing agent in the following manner. (a) Properties of dispersion: The state of particles of the obtained dispersion was evaluated by microscopic observation.

(B) Size effect: 1% pulp slurry (L
-BKP, CSF 400ml) with 10% heavy calcium carbonate as filler, cationized starch (pearl gum HMS) 0.3
% Aluminum sulfate _{[AL 2 (SO 4) 3} · 13~14H 2 O] 1.5
%, And the above sizing compositions are added in order of 0.5% and 1.0% (addition rates are air-dry pulp, solid content% by weight), and wet paper is prepared by a TAPPI standard sheet machine as usual. did. Wet paper with a 90 ° C rotary dryer
It was dried for 1 minute to obtain a paper having a basis weight of 60 g / m ² . The pH of the pulp slurry after the addition of the chemical was approximately neutral at 7.65. After conditioning at 20 ° C. and a humidity of 65% for 24 hours, the degree of Stekigto sizing (JIS P-8122) was measured. Table 1 shows the evaluation results.
Shown in

[0051]

[Table 1]

As is evident from Table 1, the sizing composition for papermaking of the present invention has excellent dispersibility and is a dispersion having a stable particle diameter. Is better.

[0053]

Industrial Applicability The present invention relates to an improvement in a rosin dispersion as a sizing agent for papermaking, and it has been proposed to obtain a cationic rosin-dispersed sizing agent effective at a high pH or a neutral range. Has been proposed, but still,
In practice, a practical cationic rosin dispersion sizing agent having both good dispersibility and excellent size effect has not been obtained. However, the present invention uses (meth) acrylamide as a dispersing agent in a cationic starch, By using as a dispersant a grafted cationic starch prepared by graft polymerization of a monomer containing the same, a cationic rosin dispersion sizing agent having both good dispersibility and an excellent size effect in a neutral region can be obtained.

Claims (4)

(57) [Claims] 1. A paper sizing composition obtained by emulsifying and dispersing a rosin-based substance with a dispersant, wherein the dispersant is prepared by graft-polymerizing monomers containing (meth) acrylamide to cationized starch. A sizing composition for papermaking, which is a cationized starch. 2. The grafted cationized starch is prepared by graft polymerization of 10 to 95% by weight of cationic starch and 5 to 90% by weight of monomers containing (meth) acrylamide. Item 7. A sizing composition for papermaking according to Item 1. 3. The emulsified dispersion contains 0.5 to 50% by weight of a grafted cationic starch in a solid content, and 50 to 99.5% by weight of a rosin-based substance.
The sizing composition for papermaking according to claim 1, comprising: 4. The sizing composition for papermaking according to claim 1, wherein the dispersant comprises a grafted cationic starch and a surfactant.