JPS63275793A - Papermaking method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Objective of the invention] (Industrial application field) The present invention significantly improves the strength of paper, and also improves the yield of fine fibers, fillers, sizing agents, and other additives in papermaking raw materials. The present invention relates to a paper manufacturing method that increases the amount of water and makes it possible to clarify white water.

(Prior art) Papermaking additives used in the papermaking process include sizing agents that improve the writability and water resistance of paper, paper strength enhancers that increase paper strength, and yield agents that improve the yield of fillers and fine fibers. Various additives are used, such as improvers, water filtering agents to promote water drainage on paper machine wires, etc.For example, water-soluble polymeric substances are generally used as paper strength enhancers and retention aids, i.e. starches and modified Water-soluble natural polymer substances such as starch and cellulose derivatives, polyacrylamide and its derivatives, polyvinyl alcohol and its derivatives, polyethyleneimine,
Polyamide polyamine-ebichlorohydrin resins, styrene-maleic resins and various other water-soluble polymers have been used.

At present, the various papermaking additives described above are facing many challenges due to the advancement of papermaking technology.

For example, in the paper manufacturing process, especially in the paper manufacturing process for printing paper and writing paper, fillers are added for the purpose of improving the whiteness and opacity of the paper and reducing raw material costs. There is a problem that paper strength decreases when the filler content in paper increases, and a solution to this problem is urgently needed. In addition, from the viewpoint of long-term shelf life of printed matter, there is a strong demand for so-called neutral paper, which is obtained by making paper in a neutral or weakly alkaline pH range without using sulfuric acid, and paper mills are now replacing the conventional paper that uses sulfuric acid in large amounts. Although the conversion from acidic papermaking to neutral papermaking is being actively carried out,
The effects of the neutral papermaking additives used for this purpose are still insufficient, and improvements are strongly desired.

Various solutions to these problems have been proposed, but recent patents show that starches have been modified with cationic agents such as quaternary ammonium and/or cationic starches. Alternatively, a paper manufacturing method using gastric guar gum and colloidal silicic acid as additives for paper manufacturing has been proposed (Japanese Patent Application Laid-open No. 51900/1983, published in 1986-5).
No. 02004), it is not fully satisfactory in terms of effects such as improvement in paper strength and improvement in filler yield.

On the other hand, the present inventors previously proposed a paper manufacturing method in which an acrylamide polymer having a cationic group and colloidal silicic acid are used as paper manufacturing additives in pulp slurry as a raw material for paper manufacturing (Japanese Patent Application Laid-open No. 15391-1982). issue).

Although the improvements in filler retention and paper strength are satisfactory, the effect of fixing the sizing agent is not fully satisfactory.

(Problems to be Solved by the Invention) As mentioned above, the requirements for the performance of papermaking additives have become increasingly strict due to the deterioration of the raw material pulp situation9, for example, the use of recycled pulp from waste paper and the decline in the water quality of papermaking water. The development of more effective papermaking additives is desired.

In particular, the effects of papermaking additives used in neutral papermaking are still not satisfactory, and improving the yield of calcium carbonate used as a filler and increasing paper strength are important issues.

Calcium carbonate is abundantly produced in Japan, and is an excellent paper-making filler that is inexpensive and has good properties, and it is extremely meaningful from an economic and industrial perspective to incorporate a high amount of calcium carbonate. However, in order to obtain neutral paper containing a large amount of calcium carbonate filler, it is necessary to increase the content of calcium carbonate in the raw material slurry to a very high level, which leads to worsening of drainage on the paper machine wire and abrasion of the wire. This has caused some operational problems, such as frequent paper breaks due to increased speed and reduced wet paper strength. The use of filler retention agents can alleviate these problems, but their effectiveness is still insufficient. Furthermore, neutral paper with a high calcium carbonate content has low paper strength and filler easily falls off the surface, which causes various problems during printing.

An object of the present invention is to provide a new paper manufacturing method that solves the above problems. More specifically.

In addition to the various chemical pulps, mechanical pipes, and regenerated waste paper pulp of the present invention, all materials made from all known types of pulp such as pulp materials made of inorganic or organic natural or synthetic fibrous materials and mixtures thereof, etc. This papermaking method is intended to provide a papermaking method that can be applied to the papermaking process, but there are some papermaking methods that can be expected to produce even better results when applied to papermaking processes that require the addition of fillers, such as the production of printing paper and writing paper. However, the present invention aims to provide a paper manufacturing method suitable as a neutral paper manufacturing method using calcium carbonate filler.

[Structure of the invention]

(Means for Solving the Problems) As a result of intensive studies to solve the above problems, the present inventors have discovered that a specific vinyl monomer mixture can be used as a papermaking additive in a starch aqueous solution. The present inventors have discovered that the above object can be achieved by using a cationic group-containing graft starch copolymer obtained by copolymerization together with colloidal silicic acid, and have completed the present invention.

To summarize the present invention, the present invention involves adding (A) a cationic group-containing grafted starch copolymer and (B) colloidal silicic acid to a papermaking raw material pulp slurry, making paper according to a conventional method,
This paper-making method is characterized by drying.

Hereinafter, the configuration of the present invention will be explained in detail.

(i) Regarding the cationic group-containing grafted starch copolymer component: (A) The cationic group-containing grafted starch copolymer component used in the present invention is a cationic group-containing grafted starch copolymer component in an aqueous solution containing starches. It is obtained by polymerizing a heptamer mixture that essentially contains a monomer containing a functional group.

The starch used in the present invention is starch and/or modified starch, more specifically wheat and rice.

Examples include various starches made from corn, potatoes, Japanese yam, tapioca, etc., and modified products thereof, such as cationic starches, etherified starches, oxidized starches, enzyme-modified starches, etc. Two or more types can be used. Among these, it is particularly preferable to use cationic starch.

The cationic group-containing monomer used in the present invention includes mono- or di-alkylaminoalkyl (meth)
Examples include acrylamide, mono- or di-alkylaminoalkyl (meth)acrylate, vinylpyridine, vinylimidazole, seven- or di-acrylamine, mixtures thereof, and quaternary ammonium salts thereof.

Among these, dialkylaminoalkyl (meth)acrylamide, more specifically dimethylaminoethyl (meth)acrylamide, dimethylaminopropyl (meth)
Acrylamide, dichelaminoethyl (meth)acrylamide, diethylaminopropylene (meth)acrylamide, and their acid salts or quaternary ammonium salts are preferred, and one or more of these monomers can be used. Among these, use of dimethylaminopropyl (meth)acrylamide and its acid salts is particularly preferred.

In the present invention, in addition to the cationic group-containing monomer, monomers such as (meth)acrylamide and (meth)acrylic acid can be used in combination. Preferred embodiments of the composition of the 7-mer mixture that essentially contains the cationic group-containing monomer of the present invention are: (1) 2 to 25 mol% of dialkylaminoalkyl (meth)acrylamide or its quaternized product, (2) (meth) Acrylic acid: 2 to 10 mol%; (meth)acrylamide: 65 to 96 mol%.

In each composition of the monomer mixture described above, (1) paper strength enhancement effect when the amount of dialkylaminoalkyl (meth)acrylamide used is less than 2 mol%;

The yield improvement effect becomes insufficient, and if it exceeds 25 mol %, it is not only economically disadvantageous, but also causes the disadvantage that the stability of the papermaking additive over time is poor. On the other hand, if the amount of (meth)acrylic acid used is less than 2 mol%, the stability over time will be poor, and if it exceeds 10 mol%, the 5 paper strength enhancement effect, 2 yield improvement effect, and size effect may be insufficient. Become.

In the present invention, the amount of starch and/or modified starch used in preparing the cationic grafted starch copolymer is preferably 20 parts by weight to 60 parts by weight. If the amount exceeds 60 parts by weight, and correspondingly if the amount of the cationic group-containing monomer mixture used is less than 40 parts by weight, it will be difficult to obtain a stable product and the paper strength enhancement effect will be reduced. 9. Yield improvement effect becomes insufficient. On the other hand, if the amount of starch used is less than 20 parts by weight, and if the amount of the cationic group-containing monomer mixture is 80 parts by weight, the additives become expensive and cannot be used industrially. In this process, economic constraints cannot be avoided.

The cationic group-containing grafted starch copolymer of the present invention is obtained by dispersing 20 to 60 parts by weight of the above starch in water, and then dissolving the starch by heating. It is obtained by adding 40 to 80 parts by weight of the mixture, stirring and mixing thoroughly, and then adding a polymerization initiator and polymerizing according to a conventional method. Specific examples of such polymerization initiators include hydrogen peroxide, potassium persulfate, ammonium persulfate, peroxides such as alkyl hydroperoxides, arbitrary redox initiator systems consisting of combinations of these with reducing agents, and azo-based initiators. Agents, etc. can be mentioned.

In addition, simply mixing a copolymer prepared by prepolymerizing the above polymer mixture with starch will result in poor stability over time;
Also, the effect is insufficient.

The amount of the cationic group-containing grafted starch copolymer may be changed arbitrarily depending on the purpose and the degree of the expected effect, but it is generally 0.05 to 5. %, preferably from 0.1 to 3%.

(ii) Regarding the colloidal silica component: The colloidal silica used in the present invention preferably has a particle size of 50 mμ or less, particularly 20+ mμ or less. Various products commercially available under the trade name Snowtex from Co., Ltd. all have particle diameters of 50 μm or less and can be suitably used.

In carrying out the present invention, the amount of colloidal silicic acid added is generally 0.01 to 2% by weight of silicic anhydride (Sin, equivalent) based on the pulp dry weight of the raw material pulp slurry. However, the range of 0.05 to 0.5% is preferable. Colloidal silicic acid can exhibit remarkable effects through interaction with the cationic group-containing grafted starch copolymer used in combination, and is not effective at all on its own; therefore, the amount added is determined to be effective. It is desirable to keep it to a minimum.

(iii) Regarding the m1 paper method: In the paper manufacturing method of the present invention, other paper manufacturing additives 1 such as sizing agents can be added in a conventional manner.

However, in the papermaking method according to the present invention, very high yield effects, excellent paper strength enhancement effects, and size effects are achieved, so it is hardly necessary to use other papermaking additives for this purpose. 1. It goes without saying that the present invention does not preclude the combined use of these other papermaking additives.

In the paper manufacturing method of the present invention, a paper manufacturing additive consisting of the above-mentioned cationic group-containing grafted starch copolymer and colloidal silicic acid is added to a papermaking raw material pulp slurry, and paper is made and dried according to a conventional method. , both can be added in any order or simultaneously.

(Talk) Regarding the interaction between the cationic group-containing grafted starch copolymer and colloidal silicic acid The mechanism of interaction between the two components has not been fully elucidated by the inventors, but both There is no doubt about the existence of an interaction between the two since the latter exhibits a tremendous synergistic effect when used alone and when both are used in combination. It is currently being speculated as if it were a law. Colloidal silicic acid, especially colloidal silicic acid sol, which is preferably used in the practice of the present invention, has a very small particle size and exhibits strong anionic properties. is thought to be absorbed almost instantaneously. On the other hand, grafted starch copolymers having cationic groups are gradually adsorbed onto the surface of ordinary pulp fibers and fillers, which exhibit weak anionic properties. When both of these are added to the raw pulp slurry, the above reactions occur simultaneously or sequentially, forming an organic-inorganic composite of the cationic groups of the cationic group-containing grafted starch copolymer and colloidal silicic acid. It is thought that a strong bond between the pulp fibers and the filler is formed through this process. In addition, when an anionic group is contained in the grafted starch copolymer containing a cationic group, the ionic group and the anion of the colloidal silicic acid particles and the grafted starch copolymer containing a cationic group are combined. It is presumed that the molecules form a network structure through ionic cross-linking with the cationic groups therein, thereby producing the amazing paper strength increasing effect, yield improving effect, and size effect of the present invention.

(Example) Hereinafter, the present invention will be described in more detail based on Adjustment Examples, Examples, and Comparative Examples, but these do not limit the scope of the present invention in any way.

Preparation Example 1 100 g of a commercially available cationic starch (AMYLOFAX15. manufactured by AVEBE) aqueous solution with 10% concentration, cooked at 90° to 100°C, 45 g of a 40% aqueous acrylamide solution, 4.
5g, 0.4g of acrylic acid, and 67g of water at 10%
Adjust the pH to 4.0 using 14.2 g of sulfuric acid solution. First, adjust the temperature to 50°C by adding 0.6 cc of 2% ammonium persulfate (APS) aqueous solution and 0.6 cc of 2% sodium bisulfite (SBS) aqueous solution. The reaction was carried out at 60 to 70°C for 3 hours to obtain a cationic group-containing grafted starch polymer (A) shown in Table 1 below.

Preparation Example 2 157 g of a 10% concentration commercially available cationic starch (AMYLOFAX15. manufactured by AVEBE) aqueous solution, 40 g of a 40% concentration acrylamide aqueous solution, dimethylaminopropylacrylamide 6.
A mixture of 6 g of acrylic acid, 1 g of acrylic acid and 146 g of water was adjusted to pH 4.0 using 18.4 g of 10% sulfuric acid. Next, the mixture was heated to 50°C with 0.8 cc of a 2% ammonium persulfate (APS) solution and 2% Sodium sulfite (SBS) aqueous solution 0
．． 8 cc was added and reacted at a temperature of 60-70°C for 3 hours to obtain a cationic group-containing grafted starch polymer (B) shown in Table 1 below.

Examples 1-2 Niscalon #800 (heavy calcium carbonate) 30 to 1% pulp slurry of L-BKP (c-3-F330cc)
% by weight, neutral sizing agent (Colopal X-11K, alkene succinic anhydride) 0.2% by weight, then Preparation Example 1
After adding 0.3% by weight of the cationic group-containing grafted starch copolymers (A) and (B) obtained in Steps 2 and 2 and mixing thoroughly, colloidal silicic acid sol (Snowtex 30
, particle size 10-20 mμ, manufactured by 8san Kagaku Kogyo) 0.1%
(Sin, converted) wt % was added and thoroughly mixed. Each adjusted valve slurry TAPP1 thus obtained
Paper was made and dried using a standard sheet machine in a conventional manner. After conditioning the humidity of each of the obtained handmade papers, the filler in the paper, the filler retention rate, the internal strength (IB), and the Stekkicht were measured. The results are also shown in Table 3 below.

Comparative Examples 1 to 3 Instead of using the cationic group-containing grafted starch copolymers (A) and CB) in Example 1, cationic group-containing polymers (a) and (b) in Table 2 below were used. A handmade paper was obtained in the same manner as in Example 1 except that cationic starch (c) was used. Similar paper quality tests were conducted on these handmade papers. The results are also listed in Table 3.

(Left below) Example 3.4 20% by weight of Niscalon #800 (ground calcium carbonate), neutral sizing agent (Corobar x-11K,
Alkenylsuccinic anhydride) 0.2% by weight, adjustment example■
After adding 0.3% by weight of the cationic grafted starch copolymers (A) and (B) obtained in (1) and (2) and thoroughly mixing them, colloidal silicic acid (Snowtex S, particles 0.1% by weight (diameter 7-9+sμ, made by 8san Kagaku Kogyo)
Sun, equivalent) was added and mixed thoroughly. Each of the prepared pulp slurries thus obtained was made into paper using a TAPP 1 standard sheet machine and dried in a conventional manner.

After conditioning the humidity of each of the obtained handmade papers, the filler in each paper, filler retention rate, internal strength (IB), and Stekkicht were measured. The results are also shown in Table 4.

Comparative Example 4.5 Colloidal silicic acid (Snowtex S1) in Example 3
A hand-made paper was obtained in the same manner as in Example 3, except that the particle size was 7 to 9μ, ml of Nichiryo Kagaku Kogyo was not added. Similar paper quality tests were conducted on these handmade papers. 4th result
Also listed in the table.

Comparative Example 6 All <
A handmade paper was obtained in the same manner as in Example 3. Similar paper quality tests were conducted on these handmade papers. The result is the fourth
It is also listed in the table.

(See margin below) (Note) Test method> Paper filler: Calculated from the ash content measurement results of dry paper using the following formula. Filler in paper (%) = Ash content in paper (%) ÷ 0.564 Internal strength (IB): J-TAPPI paper pulp test method No. 18 @ Stekicht: JIS P-8122 Based on the results of the above-mentioned example and comparative example 1 When the paper manufacturing method according to the present invention is adopted, that is, when paper is manufactured by adding a cationic group-containing grafted starch copolymer and colloidal silicic acid to the papermaking raw material pulp slurry, cationic group-containing acrylamide-based Alone, cationic-containing grafted starch copolymer alone.

The filler retention effect and internal strength (I
B) It can be seen that an excellent paper with well-balanced effects and size effects was obtained.

〔Effect of the invention〕

According to the paper making method of the present invention, a very high filler retention effect can be obtained, and paper with high strength and good size effect can be obtained. Therefore, even in paper manufacturing that uses expensive neutral sizing agents, or when producing paper with a high recirculation content, neutral sizing agents and fillers adsorb well to pulp fibers, so sizing agents for raw pulp slurry, or The addition rate of filler can be minimized, which improves water drainage on the paper machine wire, reduces wire abrasion, improves wet paper strength, prevents paper breakage, and prevents pitch stains on wire blankets, etc. Various operability will be improved, such as prevention of In addition, improving the filler retention rate reduces solid particles (SS) suspended in white water, which helps to effectively utilize raw materials and reduce the burden of wastewater treatment. Furthermore, since the paper produced by the paper manufacturing method of the present invention has extremely high strength, it is possible to further increase the filler content in the paper, making it possible to save pulp resources and significantly reduce paper manufacturing costs. It has excellent industrial value.

Patent applicant Seiko Kagaku Kogyo Co., Ltd. Agent Patent attorney Yoshio Mizuno Procedural notice (spontaneous) June 8, 1988

Claims (1)

[Scope of Claims] 1) Adding (A) a cationic group-containing grafted starch copolymer and (B) colloidal silicic acid to a pulp slurry as a raw material for papermaking, followed by papermaking and drying according to a conventional method. Characteristic paper manufacturing method. 2) The papermaking method according to claim 1, wherein the papermaking raw material pulp slurry contains a filler. 3) The paper manufacturing method according to claim 2, wherein the filler is calcium carbonate. 4) The cationic group-containing grafted starch copolymer co-contains (a) a cationic group-containing monomer and (b) monomers containing (meth)acrylamide as essential components in an aqueous starch solution. The paper manufacturing method according to claim 1, 2, or 3, which is obtained by polymerization. 5) In an aqueous solution containing 20 to 60 parts by weight of starch, the cationic group-containing grafted starch copolymer (a) 2 to 25 mol% of the cationic group-containing monomer (b) (
Claim 1, which is obtained by copolymerizing 40 to 80 parts by weight of a monomer mixture containing 65 to 96 mol% of meth)acrylamide and 2 to 10 mol% of (c) (meth)acrylic acid. The paper manufacturing method described in Section 4. 6) The paper manufacturing method according to claim 4 or 5, wherein the starch is a cationic starch. 7) The paper manufacturing method according to claim 4 or 5, wherein the cationic group-containing monomer is dialkylaminoalkyl (meth)acrylamide. 8) The paper manufacturing method according to claim 7, wherein the dialkylaminoalkyl (meth)acrylamide is dimethylaminopropyl (meth)acrylamide. 9) Claims 1, 2, and 3, wherein the colloidal silicic acid has a particle size of 5 to 20 mμ.
The paper manufacturing method according to item 4 or 5.