JPH03220397A - Papermaking method - Google Patents

Abstract

PURPOSE:To improve yield of filler and fine fibers and filtering properties on wires by co-adding amphoteric starch and colloidal silicic acid, etc., as an anionic auxiliary to an aqueous suspension of filler-containing pulp. CONSTITUTION:(A) Amphoteric starch (e.g. starch containing tertiary amino group or quaternary ammonium group as a cationic group and phosphate as an anionic group, especially starch having 0.01-0.08 substituting degree of cationic group and >=0.12% content of phosphorus is preferable) and (B) one of colloidal silicic acid, bentonite and zeolite as an anionic auxiliary are jointly added to an aqueous suspension of pulp containing filler (preferably calcium carbonate) and resultant suspension is subjected to papermaking to afford paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a paper making process that improves the retention of fillers, fine fibers and other additive chemicals during paper making and the water content on the wire.

[Conventional technology]

In general papermaking, it is customary to add filler in addition to pulp as the main papermaking raw material. As fillers for paper manufacturing, in addition to inorganic fillers such as talc, kaolin, calcium carbonate, aluminum hydroxide, and titanium dioxide, organic fillers such as urea formaldehyde resin are used.

The main reasons why fillers are used are: firstly, pulp cost can be reduced by replacing a portion of the pulp with fillers; secondly, it improves paper whiteness, opacity, smoothness,
Furthermore, printability is improved.

However, several problems arise when fillers are used as papermaking raw materials. First, with the introduction of high-speed paper machines in recent years, a significant portion of the filler passes through the wire during the unwinding process on the wire, reducing the filler yield, and this causes the wire life to decrease. As the length becomes shorter, the two-sided nature of the paper increases, and the load of circulating white water and waste water increases due to the low filler yield. As described above, the decrease in filler yield brings operational and economical disadvantages, and is also an environmental problem.

On the other hand, with the exception of paper for special purposes, for general paper, the pulp is passed through a beating machine to fibrillate it, and then a paper layer is formed on wires, which increases the hydrogen bonds in the pulp and increases the strength of the paper. . However, pulp beating reduces the reactor water properties on the wire, which causes various operational and economic problems.

For example, the paper making speed cannot be increased, the strength of the wet paper decreases and paper breaks increase, and the load of the drying process increases.

For this reason, the use of several retention aids or reactor water properties improvers has been proposed to improve filler retention and water properties on the wire. For example, a system that uses a cationic polymer substance and anionic polyacrylamide together (
JP-A No. 60-185900) is known, but although a high yield can be obtained, the agglomeration effect is too strong, resulting in a problem of deterioration of paper texture, and the reactor water resistance is also poor.

Furthermore, a method of improving the yield by using a combination of cation-modified starch and a Hofmann decomposition product of an acrylamide polymer is also known (Japanese Patent Laid-Open No. 60-65195). In this case, the yield effect will be insufficient unless a modifier having a quaternary ammonium group is added.

Furthermore, since the generated flocs are weak, they are easily destroyed by approaches to the paper machine, agitation in piping, dispersion of paper stock in the head box, etc., making it impossible to increase the yield. Furthermore, the reactor water resistance is also insufficient.

[Problem to be solved by the invention]

From the above, it can be said that an economically inexpensive paper making method that provides a high filler yield and high water resistance on the wire has not yet been established.

The purpose of the present invention is to significantly improve the filler yield on the wire and the water resistance, thereby increasing paper quality and productivity.

[Means to solve the problem]

As a result of intensive study by the present inventors on a method that can achieve a high yield of filler and fine fibers during paper making and high reactor water resistance,
The present invention was completed based on the discovery that high yield and reactor water resistance can be achieved by using amphoteric starch in combination with colloidal silicic acid, bentonite, or zeolite, and that it is also economically advantageous.

The present invention will be described below.

As the amphoteric starch, one containing a tertiary amino group or a quaternary ammonium group as a cation group and a phosphate ester as an anion group can be used. Among these, amphoteric starches having a degree of substitution of cationic groups of 0.01-0.08 and a phosphorus content of 0.12% or more are preferred.

Colloidal silicic acid, bentonite or zeolide can be used as anionic auxiliaries.

As colloidal silicic acid, one having a particle size of 50 pm or less is suitable.

The bentonite may be any one having anionic properties, and the zeolite may be either a natural zeolite or a synthetic zeolite.

In the present invention, the amount of amphoteric starch and anionic auxiliary agent added and the ratio of both need to be determined depending on the papermaking conditions 1, for example, the composition of the paper stock slurry such as the type of pulp and the type of filler, the pH of the paper stock slurry, etc. There is. - As a rough guide for fishing by boat, the amount of amphoteric starch is 0.0% relative to the solid content in the paper stock slurry.
Anionic auxiliaries are added in amounts of 0.01-0.5% for colloidal silicic acid and 0.05-5.0% for bentonites or zeolites.

In the present invention, amphoteric starch and anionic auxiliary agent are added together to the paper stock slurry, but the method of addition is not particularly specified and may be done at any stage of paper stock preparation. , may be added sequentially or simultaneously. In particular, it is preferable to add the amphoteric starch first and then add the anionic auxiliary agent. However, if the amphoteric starch and anionic auxiliary are mixed and then added to the paper stock slurry, the two will coagulate and will not form a good floc with the filler and pulp fibers, resulting in a decrease in yield and water resistance. Colloidal silica, bentonite or zeolide can also be used premixed with fillers such as calcium carbonate.

In the present invention, special consideration may be given to other commonly used papermaking chemicals such as water-soluble aluminum salts, dyes, slime control agents, sizing agents, paper strength agents, antifoaming agents, etc. It can be used without any

[Effect]

Fillers and pulp fibers carry anionic charges, and conventional retention systems neutralize these 7 anionic charges with cationic polymers, and by adding anionic polymeric substances, larger flocs can be created. Attempts have been made to improve formation yields and reactor water properties. However, there are problems in that the balance between cationic polymers and anionic substances is poor, and the effects are low unless high concentrations of these chemicals are added.

Although the function of the present invention is not completely understood, the use of amphoteric starch allows the action of cationic groups to neutralize the anionic charge of the filler and pulp fibers, while at the same time the action of anionic groups moderates agglomeration. It is believed that the combination of colloidal silicic acid, bentonite, or zeolide, which is added first, forms a strong bond between the filler, pulp fibers, and amphoteric starch.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to Examples.

However, the present invention is not limited in any way by the contents shown in the examples.

The yield of filler and fine fibers (hereinafter simply referred to as yield) was measured using a Brit jar tester.

The yield was determined by measuring the solid content in the reactor water for an initial 30 seconds from the start of stirring at a stirring speed of 1000 r, p, m, and 200 mesh wires.

The reactor water quality was determined by plugging the bottom hole using a Canadian freeness tester and measuring the number of seconds for an ip water amount of 800-.

Example 1 L-BKP of C, S, F 300- was used as the pulp, and commercially available heavy calcium carbonate for paper making (trade name: Niscalon #800, manufactured by Sankyo Seifun Co., Ltd.) was used as the filler. At this time, the paper stock was adjusted so that the ratio of pulp and filler was 3:21 and the mixed slurry concentration of both was 0.7%.

Amphoteric starch (trade name: Cato 3) is added to this stock slurry.
06JA), Cato 3210JB), manufactured by Oji Nashiyoshinal Co., Ltd.), and then colloidal silicic acid (trade name Snowtex S, manufactured by Nissan Chemical Industries, Ltd.).
A predetermined amount of each was added. The results are shown in Table 1, and the amount of chemicals added is expressed in weight percent of the solid content based on the solid content of the paper stock.

Example 2 The colloidal silicic acid used in Example 1 was replaced with natural zeolite (
Mineral specimens sold by Japan Geoscience Co., Ltd. are wet-pulverized with a sand grinder to an average particle size of 1.8p), or synthetic zeolite (Zeolum A-3, manufactured by Wako Pure Chemical Industries, Ltd.) is wet-pulverized with a sand grinder. Example 1 except that the material was wet-pulverized to have an average particle size of 1.8-
I did the same thing. The results are shown in Table 2.

Example 3 The same procedure as in Example 1 was carried out except that the colloidal silicic acid used in Example 1 was replaced with bentonite (trade name HN-1, manufactured by Kyoritsu Organic Chemical Research Institute, Inc.). The results are shown in Table 3.

Comparative Examples In Examples 1 to 3, Comparative Examples 1 and 2 were cases in which colloidal silicic acid, natural zeolite, synthetic zeolite, or bentonite were not used.

In addition, as a comparative example of the conventional technology, cationic starch (product name Hiplus 403, Sanwa Starch Industries Co., Ltd.!
! Comparative Example 3 was prepared by adding 1.0% of polyacrylamide and 0.07% of anionic polyacrylamide (trade name: Hiretin 501, manufactured by Dick Vercules Co., Ltd.).

Table 2 A Amphoteric starch: Trade name Cato 306 Amphoteric starch: Trade name Cato 3210 Table 3 Procedural amendment May 1990!

Claims (1)

[Scope of Claims] 1. In the process of manufacturing paper from an aqueous suspension of pulp containing filler, any one of: a) amphoteric starch; and b) colloidal silicic acid, bentonite, and zeolite. A papermaking method characterized by adding together as an anionic auxiliary agent. 2. The papermaking method according to claim 1, wherein the filler is calcium carbonate. 3. According to either claim 1 or 2, the amphoteric starch is an amphoteric starch containing a tertiary amino group or a quaternary ammonium group as a cationic modifying group and a phosphate ester as an anion modifying group. paper making method.