JPH06166986A - Paper-making method - Google Patents

Abstract

PURPOSE:To provide a paper-making method wherein a novel additive for paper-making is use to improve the yields of fine particles of pulp fibers and fillers in the pulp slurry and the paper formation. CONSTITUTION:This additive for paper making comprises (A) a cationic starch containing more than 0.15wt.% of basic nitrogen, (B) an acrylamide copolymer of (i) acrylamide and/or methacrylamide, (ii) itaconic acid and/or its salt and (iii) a cationic monomer and/or its salt, and (C) a water-soluble aluminum compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a papermaking method for improving the yield of fine pulp fibers and fillers in pulp slurry and improving the texture of papermaking.

[0002]

2. Description of the Related Art As a papermaking additive used in the papermaking process, a sizing agent that improves the writability and water resistance of papermaking, a paper strength enhancer that increases papermaking strength, and the yield of fine pulp fibers and fillers is improved. Various additives such as retention aids and drainage accelerators that accelerate drainage on paper machine wires are used. For example, neutral sizing agents such as rosin-based sizing agents, alkenylsuccinic anhydrides, alkyl ketene dimers, and synthetic sizing agents are used as the sizing agents. Further, as a paper-strengthening agent and a yield-improving agent, water-soluble natural polymer substances, acrylamide polymers and their derivatives, polyethyleneimine, polyamidopolyamine-epichlorohydrin resins and various other water-soluble polymers, or cationic polyacrylamides and anions are generally used. There are mentioned a dual polymer in which a water-soluble polyacrylamide is used in combination, and a method in which a water-soluble polymer and an inorganic polymer are used in combination.

However, at present, many problems have been raised by the above-mentioned various papermaking additives due to the advancement of papermaking technology. Let us consider this in the context of fillers, which are important additives for papermaking. That is, in the paper making process, particularly in the paper making process of printing paper, writing paper, and information paper, the whiteness, opacity, ink acceptability, printability, smoothness, writing characteristics, etc. of paper making are improved and the raw material cost is reduced. It is general to add a filler for the purpose of reducing the amount. From the viewpoint of long-term storage stability of printed matter, there is a strong demand for neutral paper obtained by making paper in a neutral to weakly alkaline pH range, and even in paper mills, conventional acidic papermaking and neutral papermaking that make heavy use of sulfuric acid bands are used. Is being actively converted to. However, the effect of the additive for neutral papermaking is still insufficient, and its improvement is strongly desired. Particularly in neutral papermaking, calcium carbonate is often used as the above-mentioned filler. In this case, how to improve the overall yield of alkenylsuccinic anhydride, alkylketene dimer type neutral sizing agent, fine fibers, etc. , It has become an important issue for dirt of paper making machine, wear of washer, and improvement of size effect.

To date, various proposals have been made for the above problems. For example, JP-A-57-5190
No. 0 discloses a method in which a cationic starch and colloidal silicic acid are used in combination to improve the yield of filler and the strength of paper. Further, JP-A-62-15391 discloses that a acrylamide polymer having a cationic group and colloidal silicic acid are used in combination to increase the yield of fine fibers, fillers and other additives. There is. Alternatively, JP-A-62-45798 discloses that a water-soluble copolymer obtained by using a water-soluble cationic monomer, (meth) acrylamide, and α, β-unsaturated carboxylic acid as essential constituent monomer components has a paper-strengthening effect and a filler. Yield and size yield effects are disclosed. Also, JP-A-62-125096
The publication discloses a method for improving the yield of fillers by using a zwitterionic acrylamide polymer and an aluminum compound such as alumina sol, polyaluminum chloride and polyaluminum hydroxide.

[0005]

As mentioned above, various proposals for improvement have been made in the prior art, but the demand for the performance of the additive for papermaking is the deterioration of the situation of raw pulp.
For example, the use of recycled pulp and the deterioration of the water quality of papermaking water have become more and more severe, and the development of more effective papermaking additives is desired. In particular, in order to succeed in neutral papermaking using calcium carbonate as a filler, it is essential to secure a fine pulp fiber in the pulp slurry and the yield of the filler. , Causing paper breaks and causing operational problems such as significantly deteriorating operability.

Therefore, various yield improvers and yield improvement systems have been proposed as described above, but the effect is still insufficient, and even if the yield is improved, the texture is deteriorated. There is also a drawback. Needless to say, formation is defined as the homogeneity of the distribution of pulp fibers in the paper. When the pulp fibers are non-uniformly dispersed and the transmitted light looks uneven and looks like a cloud, it is called that the texture is poor or rough. The formation characteristics described above are the appearance and physical properties of paper,
This is a very important property because it affects optical properties such as color, whiteness, and gloss. An object of the present invention is to provide a novel papermaking method for improving the yields of fine pulp fibers and fillers in a pulp slurry, and for obtaining a papermaking paper with excellent formation of the papermaking paper.

[0007]

Means for Solving the Problems To summarize the present invention, the present invention provides a pulp slurry containing a raw material pulp for papermaking and a filler, in a method of papermaking, drying and papermaking, wherein (A) ) Cationic starch containing 0.15% by weight or more of basic nitrogen, (B) an acrylamide-based copolymer comprising the following (i) and (ii) and / or (iii) a copolymerizable monomer: (i) Acrylamide and / or methacrylamide, (ii) Itaconic acid and / or its salts, (iii) Cationic monomers and / or their salts, (C) Water-soluble aluminum compound, and papermaking The present invention relates to a paper manufacturing method characterized by the above.

The technical constitution of the present invention will be described in detail below. First, the cationic starch containing the basic nitrogen as the component (A) will be described. In the present invention, the basic nitrogen-containing cationic starch (A), corn, potatoes, tapioca, sweet potato, wheat, rice, etc. by known means to raw starch, primary, secondary, tertiary Various cation-modified starches having a basic nitrogen atom in the form of one or more selected from amine and quaternary ammonium group are used. Among the above-mentioned ones, for example, as a method for producing a cationic starch containing a quaternary ammonium group, there are a wet method using an aqueous medium and a dry method utilizing a solid / liquid phase reaction. Is adopted.
The wet method is a method in which a cationizing agent consisting of a reaction product of dialkylamine or trialkylamine and epichlorohydrin is reacted with starch in the presence of an alkali in an aqueous medium, whereby the cationic starch is efficiently produced. Manufactured to. In the present invention, the cationic starch should contain a certain amount of nitrogen content. As demonstrated by the examples described below, 0.1 in relation to the action and effect.
Cationic starch with a nitrogen content of 5% by weight or more is recommended.

Next, the acrylamide-based copolymer which is the component (B) of the present invention is generally (i) acrylamide and / or methacrylamide ...
… 80-99 mol%, (ii) Itaconic acid and / or its salts …………………………
... 1 to 10 mol%, (iii) cationic monomer and / or salts thereof ...
It is obtained by copolymerizing a monomer mixture consisting of 0 to 10 mol%. When using the acrylamide-based copolymer (B) containing an anionic group and / or a zwitterionic group prepared under the above-mentioned monomer ratio, particularly excellent fine fiber and filler yield improving effect, and You can get the perfect paper.

As the anionic group of the acrylamide copolymer (B), itaconic acid and / or its salts are essential components. Other anionic monomers, for example, known anionic monomers such as acrylic acid, methacrylic acid, maleic acid and fumaric acid cannot achieve the object of the present invention. As the cationic monomer of the present invention, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate, dimethylaminopropyl acrylamide, a monomer having a tertiary amino group such as diethylaminopropyl methacrylamide and a mixture thereof,
Or a salt of an inorganic or organic acid such as hydrochloric acid, sulfuric acid, acetic acid or sulfonic acid, or a quaternary ammonium salt obtained by reacting the monomer having a tertiary amino group with a quaternizing agent. It can be illustrated.

To copolymerize the copolymerizable monomer,
For example, an aqueous solution having a monomer component concentration of 5 to 20% by weight is used, and a polymerization initiator is added in a nitrogen stream at 30 to 80 ° C.
The reaction may be performed within the range of 3 to 10 hours. As the polymerization initiator, potassium persulfate, ammonium persulfate, peroxides such as hydrogen peroxide, or redox type initiators or 2,2 ′ used in combination with these peroxides and a reducing agent such as sodium hydrogen sulfite or sodium sulfite. Azo compounds such as azobis-2 amidinopropane hydrochloride can be used.

Examples of the water-soluble aluminum compound which is the component (C) of the present invention include aluminum sulfate (sulfate band),
Examples thereof include aluminum chloride, polymerizable polyaluminum chloride, polyaluminum hydroxide, and alumina sol.

The main component of the polyaluminum chloride is represented by the following general formula (1) [Al ₂ (OH) n Cl _6-n ] (1), which is an aqueous solution or powder. Is commercially available, and any of them is preferably used.

The polyaluminum hydroxide is represented by the following general formula (2) [Al (OH) ₃ ] n AlCl ₃ (2), and the commercially available product has a value of n of about 20. It has a higher basicity and is distinguished from the above polyaluminum chloride.

The alumina sol is generally 5 to 200 m
It is a colloidal solution composed of an aggregate of feather-like particles having a size of about μ, and one having a specific surface area of 200 m ² / g or more is preferably used.

The use ratios of the three components (A to C) of the present invention may be appropriately determined, but the general addition amount is the component (A) with respect to the dry weight of the pulp. 2 to 2% by weight, component (B) ... 0.01 to 0.5% by weight, component (C) ... 0.1 to 2% by weight. In addition, when calcium carbonate is used as a filler, foaming tends to occur when the sulfuric acid band increases,
(C) is preferably used in the range of 0.1 to 1% by weight. The addition of the three components (A to C) of the present invention to the papermaking raw material,
It can be done in any order or simultaneously at any location before the wet sheet is formed.

The filler used in the present invention includes:
Any of various known fillers used in conventional papermaking processes can be used, for example, heavy calcium carbonate, light calcium carbonate, kaolin, titanium dioxide, clay, calcined clay, synthetic silica, aluminum hydroxide, etc. are used. You can Particularly, heavy calcium carbonate or light calcium carbonate is preferable. Alternatively, a mixture of the calcium carbonate and the other filler is also preferable.

Regarding the interaction of the above-mentioned three components (A to C) of the present invention, the mechanism has not been sufficiently elucidated by the inventors. In any case, as demonstrated in Examples described later, in comparison with the case where the three components are used alone or the case where the two components are used in combination, the combination of the three components of the present invention has a great synergistic effect. Since it does appear, its effect is unquestionable.

[0019]

EXAMPLES The present invention will be specifically described below based on preparation examples, examples and comparative examples. These do not limit the scope of the invention in any way.

Preparation Example (Preparation of Acrylamide Copolymer) Preparation Example No. 1: 40% in a 500 ml four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube.
Concentration acrylamide aqueous solution 91.0 g, itaconic acid 3.6 g, dimethylaminopropyl acrylamide 1.
7 g of water and 185.0 g of water are charged, and the pH is adjusted to 4.0 using a 10% aqueous potassium hydroxide solution. Then, while stirring while passing nitrogen gas, an internal temperature of 60 ° C. and a 5% concentration of 2,2 ′
-Azohis-2-amidinopropane hydrochloride 0.6 g aqueous solution was added to initiate polymerization, and the temperature was 60-
A polymer was obtained by keeping the temperature at 70 ° C. for 6 hours. The solid content of this product was 15.2%, and the viscosity at 25 ° C was 10 with a B-type viscometer.
It was 500 cps. This is designated as Preparation Example No. 1. The outline of Preparation Example No. 1 is shown in Table 1 below. Preparation Examples Nos. 2 to 14: As Preparation Examples Nos. 2 to 14, Table 1
A copolymer was obtained by the same procedure as in Preparation Example No. 1 with the monomer composition shown in 1. Table 1 shows the ratio (mol%) of the monomer and the solid content and viscosity of the copolymer. The symbols relating to the monomers in Table 1 below mean the following. -AAM: acrylamide-IA: itaconic acid-MA: maleic acid-AA: acrylic acid-MAA: methacrylic acid-DMAPAA: dimethylaminopropyl acrylamide-DM: dimethylaminoethyl methacrylate-DAA: dimethylaminoethyl acrylate-DAC: DAA Methyl chloride quaternary product of DMC: DM Methyl chloride quaternary product As described above, Preparation Examples Nos. 12 to 14 are preparation examples of copolymers serving as comparative examples.

[0021]

[Table 1]

Examples 1 to 26 / Comparative Examples 1 to 11 Hardwood bleached kraft pulp (L-BKLP, C.S.F4
(50 ml) based on the weight (% by weight) of the air-dried material, 0.6% L-BKP pulp slurry to which 2% of light calcium carbonate was added in advance, and various components shown in Table 2 were added to prepare a pulp slurry. It was prepared and the retention effect was evaluated. The results are shown in Table 2. In Table 2, the sulfuric acid band is the water-soluble aluminum compound component of the present invention. Cationic starch is a cationic starch containing basic nitrogen of the present invention, and the sources and nitrogen contents of those listed in the type column in the table are as follows. Pearl gum HMS: manufactured by Hoshiko Kagaku Kogyo Co., Ltd. N content 0.33% amylofax T-2200: manufactured by Matsutani Chemical Co., Ltd. N content 0.23% amylofax PW: manufactured by Matsutani Chemical Co., Ltd. N content 0.35% amylofax HS : Matsutani Chemical Co., Ltd. N content 0.45% Amylofax T-1100: Matsutani Chemical Co., Ltd. N content 0.12%

The evaluation of the yield effect was carried out according to the following procedure. (i) Yield measurement method (OPR-one-pass retention) A Brit jar tester was used. A 60-mesh plastic wire was used as the tester wire. (ii) Measurement procedure (1) 500 ml of the above pulp slurry was put into a jar and stirred at 1500 rpm, and a sulfuric acid band was added to start timing. If the sulfuric acid band is not added, start timing in the same manner. (2) After 40 seconds, add cationic starch. Continue stirring only when no cationic starch is added. (3) After 40 seconds, the preparation example copolymer is added. Continue stirring only if not added. (4) After 40 seconds, add 10% of light calcium carbonate to pulp. (5) After 20 seconds, reduce the rotation speed to 750 rpm. (6) After 20 seconds, add the final retention agent. (7) Start draining after 5 seconds and do not collect water for the first 10 seconds. The same operation is performed when the final retention agent is not added. (8) After 10 seconds from the start of drainage, start collecting the filtrate,
Collect ml of filtrate. (9) Quantitative filter paper of known weight (Toyo Filter Paper N
o.3) and then dried at 105 ° C. to obtain the weight of the solid content, which was designated as f. (10) Then, bake at 500 ℃ to make ash, obtain the ash weight,
Let this be t. (11) 0.6% of the original which added the light calcium carbonate of (4)
An accurate weight of solid content (fiber + filler) in 100 ml of pulp slurry is determined and designated as F. (12) Similarly, find the accurate ash content of (11) and set this as T. (13) The yield rate was calculated by the following formula. -Total yield (%) = {(F-f) / (F)}-100-Total yield (%) = {(T-t) / (T)}-100

[0024]

[Table 2]

Examples 27-32 / Comparative Examples 12-14 L-BKP, C.I. S. Based on the air-dried product of F470 ml (% by weight), L-containing 2% of light calcium carbonate in advance
The BKP pulp slurry was used and various components shown in Table 3 were added to prepare a pulp slurry, and the texture and size effect of the papermaking and the yield effect were evaluated. The results are shown in Table 3. In Table 3, as a sizing agent, Hercon 603 (manufactured by Dick Hercules Co., Ltd.) and as a polymer retention agent, HYMOLOCK NR-11L (HYMO Co., Ltd.)
Snow Tech. S (manufactured by Nissan Chemical Industries, Ltd.) was used as the colloidal silica.

The texture, size effect, and yield effect of the above-mentioned paper were tested in the following manner (handmade paper test). Various chemicals shown in Table 3 were sequentially added to the above 1% L-BKP pulp slurry, and after stirring, using a TAPPI standard sheet machine according to a conventional method,
A handmade sheet corresponding to a rice basis weight of 5 g / m ² was prepared.
Then after 5 minutes pressing handsheet sheet press ^{3.5Kg / cm 2, 1.5Kg / cm} 2 the pressure of each handsheet paper obtained by drying for 1 minute at a steam drier and more moisture-conditioned to JIS method, adult Paper texture and size effects and filler retention were tested. The filler yield rate was calculated by the following formula. <Yield measurement formula> Filler retention rate (%) = {(added filler 500 ° C ash content-formed paper 50
(0 ° C. ash content) / (added filler 500 ° C. ash content)} · 100 <Evaluation of texture of formed paper> The texture of the formed paper was visually evaluated according to the following evaluation criteria. ×× ………… Very inferior × ………… Inferior ○ ………… Good

[0027]

[Table 3]

[0028]

INDUSTRIAL APPLICABILITY The papermaking additive comprising a cationic starch containing a specific amount of nitrogen, a specific acrylamide copolymer, and a water-soluble aluminum compound of the present invention is particularly neutral using calcium carbonate as a filler. It is useful as a papermaking additive. The papermaking additive of the present invention not only improves the yield of the filler as compared with the conventional additive, but also has a favorable effect on the texture and size effect of the papermaking, and thus can be evaluated as a comprehensive additive.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 7199-3B D21H 3/68

Claims (3)

[Claims] 1. A method of papermaking, drying a pulp slurry containing a raw material pulp for papermaking and a filler to produce paper, wherein the pulp slurry contains (A) a cation containing 0.15% by weight or more of basic nitrogen. Starch, (B) an acrylamide-based copolymer comprising the following (i) and a copolymerizable monomer (ii) and / or (iii), (i) acrylamide and / or methacrylamide, (ii) itaconic acid and And / or a salt thereof, (iii) a cationic monomer and / or a salt thereof, and (C) a water-soluble aluminum compound are added to produce a paper. 2. The filler is calcium carbonate.
The paper manufacturing method described in. 3. The acrylamide copolymer is (i) acrylamide and / or methacrylamide ...
… 80-99 mol%, (ii) Itaconic acid and / or its salts …………………………
... 1 to 10 mol%, (iii) cationic monomer and / or salts thereof ...
The papermaking method according to claim 1, which comprises 0 to 10 mol%.