JPH048558B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for making acid-free paper that improves the retention of fillers, fine fibers, etc. during paper making, and improves freeness on wires. [Prior Art] In general papermaking, it is customary to mix 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. Particularly in neutral papermaking, a filler mainly composed of calcium carbonate is used. The main reasons why fillers are used are: firstly, pulp costs can be reduced by replacing a portion of the pulp with fillers; secondly, it improves paper whiteness, opacity, smoothness, and printing performance. can give. However, the use of filler as a papermaking raw material causes several problems because a significant portion of the filler passes through the wire during the escape process on the wire. The first point is that wire wear in the paper machine increases and the wire life is shortened, and the second point is that the load on circulating white water and wastewater increases due to the low filler yield. On the other hand, with the exception of paper for special purposes, the strength of the paper is increased by passing a pipe through a beating machine to fibrillate it and then forming a paper layer on a wire. However, since pulp beating reduces freeness on the wire, various operational and economical problems occur. 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 improvers and freeness improvers has been proposed in order to improve the yield of calcium carbonate, etc., or to improve the freeness on the paper machine. As a recent example, a system using a cationic polymer and anionic polyacrylamide in combination is disclosed in JP-A-60-185900. On the other hand, the following techniques are similar to the present invention using zeolite. JP-A No. 58-60097 describes the use of substances (natural zeolite, synthetic zeolite,
Diatomaceous earth, activated clay, synthetic aluminum silicate,
A method is disclosed in which a nonionic polymer (polyacrylamide, polyethylene oxide) is added after the addition of synthetic calcium silicate, synthetic magnesium silicate, and then a nonionic polymer (polyacrylamide, polyethylene oxide) is added. In addition, a papermaking method in which this method was applied to mechanical pulp was published in Japanese Unexamined Patent Publication No. 1983-
60098. Also, JP-A-58-180696
In this method, inorganic substances with ion exchange ability (bentonite, zeolite, activated clay, diatomaceous earth, synthetic aluminum silicate, synthetic calcium silicate, synthetic magnesium silicate) and anionic polyacrylamide are added to the paper stock suspension. A method for making paper by adding Although relatively high yields can be obtained in all of these methods, the aggregation effect of cationic, nonionic, or anionic properties is too strong and deterioration of the paper's texture is unavoidable. Also, the freeness is insufficient. As described above, it can be said that a neutral paper making method that can satisfy sufficiently high yield and good freeness and formation has not yet been completed. [Problems to be Solved by the Invention] An object of the present invention is to provide a neutral paper making method that provides sufficiently high yield and freeness on a paper machine and has good formation. [Means for Solving the Problems] As a result of extensive research into a method that can achieve high yield and good freeness and formation in neutral papermaking, the present inventors have developed a method that uses a cationic water-soluble polymer and zeolite in combination. The present inventors have discovered that a high yield and good freeness and formation can be obtained by doing so, and have completed the present invention. The present invention will be described below. As a raw material for the cationic starch, any material such as corn, wheat, tapioca, potato, waxy maize, etc. can be used. Furthermore, a substituent containing a tertiary amino group or a quaternary ammonium group can be used.
Among them, it especially has a quaternary ammonium group,
And those with a degree of substitution (DS/glucose unit) of 0.02 or more are preferred. As the cationic polyacrylamide, Huffmann decomposition product or Mannitz reaction product of polyacrylamide, or (meth)acrylamide and 3
Examples include copolymers with various (meth)acrylate monomers and/or (meth)acrylamide monomers containing a grade amino group or a quaternary ammonium group. The molecular weight is preferably about 100,000 to 10,000,000. As a general guideline, the amount of cationic water-soluble polymer added is 0.01 to 2.0% based on the solid content of paper stock.
is possible. Regarding zeolites, natural zeolites and synthetic zeolites can be used. Natural zeolites include analcime, cha-bazite, clinoptilolite, heulandite, erionite, ferrierite, and laumo-ntite. Examples include zeolites containing , mordenite, etc. as components. On the other hand, synthetic zeolites include A, NA,
X, Y, hydroxy sodalite, ZK-5, B, Ω,
R, G, D, T, L, hydroxy cancrinite, W,
Various types of zeolites such as Zeolon, C are used. The average particle diameter of the zeolite is preferably 5 microns or less in order to reduce wire abrasion, and the additive is considered to be 0.5 to 5% based on the solid content of the paper stock. In the present invention, a cationic water-soluble polymer and zeolite are added to the paper stock slurry, but the method of addition is not particularly defined and may be done at any stage of paper stock preparation, sequentially or They may be added at the same time. In particular, a method of adding zeolite after adding a cationic water-soluble polymer is more suitable. However, if the two are mixed and then added to the paper stock slurry, both will coagulate and the yield and freeness will drop significantly. Zeolite can also be added in a premixed state with calcium carbonate, etc., which is a filler for neutral papermaking. In the present invention, other chemicals such as dyes, slime control agents, sizing agents, paper strength enhancers,
Any commonly used papermaking chemicals such as sulfuric acid can be used in combination without special consideration. [Function] Cationic water-soluble polymers are adsorbed to the pulp and filler in paper stock slurry and have the effect of improving yield and freeness, but since they are originally water-soluble, their adsorption is not complete. A portion of it remains unadsorbed and flows out into white water during the dehydration process.
Although the action of zeolite is not completely understood, it is thought that it forms a complex with cationic water-soluble polymers due to its anionic surface charge. As a result, the fixation of the cationic water-soluble polymer in the paper layer becomes complete, and it is thought that the effects of improving yield and freeness are maximized. In addition, it is thought that good formation can be maintained by lowering the solid content concentration of paper stock due to improved yield. [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 amount of the chemical added is expressed in weight percent of the solid content relative to the solid content of the paper stock. Filler retention was measured using a blitzer tester. The stirring speed was 1000 R.PM, and the experiment was conducted using a 200 mesh wire. Freeness was measured using a Canadian freeness meter. The bottom hole of the freeness meter was closed, and the number of seconds required to obtain 800 ml of drainage was measured. The smaller the number of seconds, the better the freeness. Handmade paper was prepared using a TAPPI standard sheet machine and its texture was visually evaluated. Example 1 350 ml of CSF L-BKP was used as pulp, and commercially available heavy calcium carbonate for paper manufacturing (trade name: Escalon #800, manufactured by Sankyo Seifun Co., Ltd.) was used as filler.
It was used. A paper stock was prepared so that the ratio of pulp to filler was 3:2 and the mixed slurry concentration of both was 0.7%. A cationic modified starch containing a quaternary ammonium group (trade name: Perfectamyl PW, manufactured by Matsutani Chemical Co., Ltd.) was added as a cationic water-soluble polymer to this paper stock slurry, and then natural zeolite (Nihon Geokagakusha Co., Ltd.) was added. We wet-crush mineral specimens on sale with a sand glider to determine the average particle size.
1.8 μm, main component is clinoptilolite) or synthetic zeolite (trade name: Zeolum A-3, manufactured by Wako Pure Chemical Industries, Ltd., type A zeolite,
Wet grinding with a sand grinder average particle size 1.8μ
A predetermined amount of m) was added. Example 2 The same procedure as in Example 1 was carried out except that the cationically modified starch used in Example 1 was replaced with cationic polyacrylamide (trade name: Hiholder-301, manufactured by Kurita Water Industries, Ltd.). Example 3 Cationically modified starch containing a quaternary ammonium group (Example 1) was used as a cationic water-soluble polymer.
The same procedure as in Example 1 was carried out except that cationic polyacrylamide (same as in Example 2) and cationic polyacrylamide (same as in Example 2) were used in combination. Comparative Examples In each example, cases in which natural zeolite or synthetic zeolite was not added were shown as Comparative Examples 1, 2, and 3. Comparative Examples 4 and 5 show cases in which a cationic water-soluble polymer and anionic polyacrylamide (trade name: Hireten 501, manufactured by Deik Hercules Co., Ltd.) were used in combination. On the other hand, using the same zeolite as in the example,
Polyethylene oxide (manufactured by Wako Pure Chemical Industries, Ltd.) in place of the cationic water-soluble polymer of the present invention,
Comparative Examples 6 and 7 show cases where anionic polyallylamide (average molecular weight: 4 million) or anionic polyallylamide (trade name: Hireten 501) was used.

[Table] * Condition ◎…Very good ○…Good △
…Slightly poor, ×…Poor

【table】

【table】

〔Effect of the invention〕

The tables shown in Examples 1 to 3 and Comparative Examples 1 to 9 (Tables 1 to 4) show that the present invention improves filler yield and paper machine performance while maintaining good paper formation compared to the conventional technology. The effect of increasing freeness in water is remarkable, and its industrial value is extremely high.

Claims (1)

[Claims] 1. In the process of manufacturing paper from an aqueous suspension of pulp containing a filler and having a pH of 6 to 9.5, a cationic water-soluble polymer and zeolite are added before paper making. Neutral paper making method. 2. The neutral papermaking method according to claim 1, wherein the filler is calcium carbonate. 3. The neutral papermaking method according to claim 1, wherein the cationic water-soluble polymer is a cationic starch containing a tertiary amino group or a quaternary ammonium group. 4. The neutral papermaking method according to claim 1, wherein the cationic water-soluble polymer is cationic polyacrylamide. 5. The neutral papermaking method according to claim 1, wherein the cationic water-soluble polymer is a cationic starch and a cationic polyacrylamide containing a tertiary amino group or a quaternary ammonium group.