JPH0345799A - Production of paper - Google Patents

Abstract

PURPOSE:To increase yield of pulp fine fiber and filler, to improve filtering characteristics and to obtain high-quality and middle-quality neutral paper by blending paper stock containing pulp and filler with amphoteric starch, water-swelling cationic polymer and bentonite. CONSTITUTION:Paper stock comprising pulp containing 10-50% high-yield pulp and filler is blended with amphoteric starch starch [e.g. starch such tapioca replaced with tertiary or quaternary amine, having 0.2-0.3 degree of substitution (DS)], a water-swelling cationic polymer, bentonite (preferably having >=10meq/100g cation demand and preferably a water-soluble aluminum salt or cationic fixing agent and made into paper in a neutral range to give the aimed paper.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper manufacturing method, in particular, a paper manufacturing method using a raw material containing filler, high-yield pulp and raw material containing filler, and high-speed papermaking in a neutral region. The present invention relates to a method for producing high-quality and medium-quality neutral paper, which improves the yield of pulp fine fibers and filler and freeness, and improves operability.

[Conventional technology] Several types of chemicals are used in the production of paper.

These chemicals provide additional filli value to the paper and
This is to improve operability. For example, sizing agents such as alkyl ketene dimers can be used to improve ink bleeding, dry strength agents such as starch and polyacrylamide can be used to improve physical strength, and dry strength agents such as starch and polyacrylamide can be used to improve wet strength. wet paper strength agents such as polyamide polyamine-epichlorohydrin are used. Fillers such as talc, kaolin, calcium carbonate or titanium dioxide are also added to improve the opacity and whiteness of the paper.

Furthermore, various yield improvers are used for the purpose of improving the yield of pulp fine fibers and fillers in order to reduce production costs and improve operability by maximizing the characteristics of the chemicals and fillers mentioned above. .

As a method for improving yield in neutral paper making, JP-A-63
JP-A-275793 discloses a method using a cationic group-containing grafted starch copolymer and colloidal silicic acid, and JP-A-63-295749 discloses a method using a cationic water-soluble polymer and aqueous sodium silicate. Method, JP-A-1-9
No. 2498 discloses a method of using bentonite, colloidal silicic acid and starch in combination, and JP-A-63-235.
No. 596 discloses a method using a water-swellable cationic copolymer and an acrylamide polymer.

[Problems to be Solved by the Invention] In order to reduce paper manufacturing costs and improve operability, a good yield of pulp fine fibers and filler is an essential condition. In order to efficiently retain the fine fibers and filler in the paper stock in the paper layer during high-speed papermaking, the fine fibers and filler are adsorbed by physical and chemical forces to the long pulp fibers that do not pass through the paper layer forming wire. things are necessary.

Various yield improvement methods are known for this purpose. Specifically, high molecular weight water-soluble electrolytes such as cationic and anionic high molecular weight polyacrylamide and polyethylene oxide (nonionic) are added, or as mentioned above, cationic water-soluble polymers or cationic starch and anionic Two types of chemicals, cationic and anionic, have been used in combination, such as a combination of colloidal silicic acid.

However, these existing yield improvement methods have not yielded fully satisfactory results. That is, as the paper weight becomes lighter and the speed increases, the yield deteriorates, and as a result, the operability also deteriorates. As a countermeasure to this problem, a method of increasing the amount of a high molecular weight retention improver causes the formation of the paper to deteriorate, so the upper limit of the amount added is limited, and a sufficiently satisfactory yield cannot be obtained.

Furthermore, even when two existing chemicals are used together, it has not been possible to satisfy both formation and good yield. In addition, high-yield pulp contains many anionic impurities that inhibit the effectiveness of retention aids, further complicating the problem.

The purpose of the present invention is to reduce the yield of pulp fine fibers and filler during high-speed papermaking in a neutral region using paper stock containing filler or paper stock containing filler and high-yield pulp. An object of the present invention is to provide a method for producing high-quality and medium-quality neutral paper that has improved drainage properties and improved workability.

[Means for Solving the Problems] As a result of repeated studies on retention improvers for paper stocks containing pulp and fillers in the neutral to weakly alkaline range of pH 7 to 9, the present invention has developed an amphoteric starch, water We have discovered that the combination of a swellable cationic copolymer and bentonite is extremely effective in improving yield under high shear forces, with almost no deterioration of the formation observed. In addition, in the case of paper stocks containing high-yield pulp and a large amount of filler, good yield and formation can be obtained in the same system as bleached pulp by adding a cationic fixing agent to the high-yield pulp. I discovered that pitch troubles can also be avoided.

The present invention will be explained in detail below.

The pulp referred to in the present invention is pulp obtained by cooking wood by the kraft method or sulfide method and then bleaching it.

In the present invention, high-yield pulp refers to pulp that has a higher yield during production than chemical pulp, such as kraft pulp, and includes stone ground wood pulp (GP), refined ground wood pulp (RGP), and thermoplastic pulp. Mechanical pulp (TMP), chemical ground pulp (C
GP), Chemothermomechanical pulp (CTMP)
, refers to pulp such as waste paper pulp (DIP). These pulps always contain organic and inorganic impurities generated during production, and it is known that these are one of the causes of poor yield and operability. Furthermore, if 50% or more by weight of these high-yield pulps is added, the surface becomes rough and is not suitable as a high-grade coated base paper.

The fillers used in the present invention include common mineral fillers such as light calcium carbonate, heavy calcium carbonate, kaolin, calcined kaolin, titanium dioxide, talc, chalk, synthetic silica,
Refers to aluminum hydroxide.

Light calcium carbonate and heavy calcium carbonate are preferably used in neutral papermaking, but they can also be used in combination with other fillers. Furthermore, the stock contains fillers derived from broque and coat broque in addition to newly added fillers.

The amphoteric starch referred to in the present invention refers to starch of tapioca, corn, or horse yam substituted with a tertiary or quaternary amine, and preferably has a degree of substitution (DS) of 0°1 to 0.4, or more. Preferably it is from 0.2 to 0.3. Furthermore, it is preferable that this starch has cohesive properties with bentonite as described below.

The water-swellable cationic polymer referred to in the present invention is JP-A-63
It is a polymer gel as described in Japanese Patent No. 235596.

The bentonite referred to in the present invention is an ultrafine clay known as montmorillonite clay, which swells in water to form a layered silicate. Preferred bentonite for the present invention has a cation requirement of 6 meq/
100 g or more, more preferably 10 meq/100 g
That's all.

The water-soluble aluminum salt or cationic fixing agent referred to in the present invention refers to a fixing agent made of polyaluminum chloride, aluminum hydroxide, or a polyamine polymer and having cationic properties.

Specifically, amphoteric starch is added to the pulp slurry containing filler and block in an amount of 0.5 to 2%, more preferably 0.5 to 2%, based on the weight of the pulp. Add 7 to 1.2% and stir until uniform. If the amount added is less than 1.5%, the interaction with bentonite becomes weak, and if it is more than 2.0%, the interaction between the water-swellable cationic copolymer and bentonite and the stability within the papermaking system are disturbed, which is not preferable. Next, a water-swellable cationic copolymer is added in an amount of 0.01 to 0.08%, more preferably 0.02 to 0.05%, based on the weight of the pulp, and stirred until uniform. If the addition amount is less than 0.01%, a good yield cannot be expected, and if it is more than 0.08%, there is a high possibility that the formation will deteriorate, and furthermore, the cost will increase, which is not preferable. Finally, add 0.0% bentonite to the pulp weight. 1 to 0
．． 5%, more preferably 0.15 to 0.5%. Add 4% and stir until uniform. If it is less than 0.1%, a good yield cannot be expected, and if it is more than 0.5%, there is a high possibility that the formation will deteriorate. The above three types of chemicals may be used in any ratio as long as they are within the above range, and more preferably the zeta potential is in the range of -25 to 15 mV. Preferably, chemical addition is completed before the fan pump or screen.

In the case of paper stock containing high-yield pulp and filler, polyaluminum chloride (trade name PAC- 250A), polyaluminum hydroxide and activated alumina or polyamine-based polymer adhesion promoters to high yield pulp weight 0605 to 0.5%, more preferably 0.1 to 0.3%, other pulps and fillers Add and stir evenly before mixing. Although these fixing agents do not improve the yield even if added in excess of the necessary amount, it is possible to produce a good paper by using this high-yield pulp and fixing agent and using the same method as the paper manufacturing method that does not use the above-mentioned high-yield pulp. Yield can be obtained.

[Example] Preparation Example-1 The paper stock used in the test was prepared as follows. Lab beater for LBKP and NBKP respectively
It was beaten to a freeness of 400 ml and 450 ml. Light calcium carbonate is added as a filler to a pulp mixture in which the above pulps are mixed at a weight ratio of L/N=8/2 in an amount of ↓5% based on the weight of the pulp, and the mixture is stirred uniformly. Furthermore, solid content was added to this paper stock containing filler so that the weight ratio of the solid content that had passed through 100 meshes of this paper stock was 7/3 to prepare a sample with a concentration of approximately 0.6%. .

Preparation Example-2 CGP is refined to a freeness of 300 ml using a laboratory refiner. LBKP and N prepared under the same conditions as Preparation Example-1
Light calcium carbonate is added as a filler to a pulp mixture in which the weight ratio of BKP and CGP is 4/2/4 based on the weight of the pulp, and the mixture is stirred uniformly. Furthermore, white water solids were added so that the weight ratio of the filled paper stock and the solids passing through the 1°O mesh of this paper stock was 7/3, and the concentration was about 0.
The stock was adjusted to 6%.

Yield measurement method A: 500 ml of paper stock is placed in a Brit jar using a bronze wire (LV70 manufactured by Nippon Filcon Co., Ltd.) as a mesh, and stirred at 500 + pm.

B, 0.5% sulfate based on pulp weight, amphoteric starch,
Sizing agent (commercial name Barcon W manufactured by Dick Vercules)
) is 0.0% relative to pulp weight. 2%, water-swellable cationic copolymer, and bentonite were added at 30 second intervals.

C. After adding bentonite, increase the rotation speed to 3000.
Increase the temperature to +pm and stir for 15 seconds.

After lowering the rotation speed to 80 Ofpm, start draining. The drainage speed at this time was adjusted to 200 m1/min.

E. After starting drainage, collect 100ml of filtrate and filter it with quantitative filter paper (No5C manufactured by ADVANTEC).
Measure the bone dry weight at 5°C.

The F9 yield is determined by the following formula.

(1-Wastewater solid content concentration/paper stock concentration) X100 Zeta potential measurement method 40 The sample slurry after the yield measurement is filtered through a 150 mesh.

Insert the filtrate into PEN KEM LASERZEE
Measured using Model 1500.

Method for measuring cation demand: Dilute 0.2 g of silicate with 350 ml of ion-exchanged water, add TB indicator, and titrate with N/200 methyl glycol chitosan.

Examples 1 to 6 In Examples 1 to 6, amphoteric starch (trade name: Cat manufactured by Oji National Co., Ltd.) was added to the sample slurry of Preparation Example 1 as a retention improver.
o3210) in an amount of 0°25 to 3% based on the weight of the pulp, a water-swellable cationic copolymer (product name: Acuratsuku MG↓024, manufactured by Mitsui Suyanamitsu Co., Ltd.) in an amount of 0.005 to 0.05% based on the weight of the pulp, and bentonite (Allied). Colloid (trade name: Organosorb) to pulp weight ff10.
The filler yield was measured using the above-mentioned yield measuring method by adding the filler in an amount of 0.05% to 0.5% within the range shown in Table 1.

Comparative Examples 1 to 3 In Comparative Examples 1 to 3, Cato3210 was replaced with a degree of substitution of 0. 1 to 0. Example 2 except that the cationized starch (product name 0NL200, manufactured by Oji National Co., Ltd.) of Example 2 was used.
It was carried out under the same conditions as in 4.

The above results are shown in Table-1.

Examples 7 to 10 In Examples 7 to 10, the sample slurry of Preparation Example-1 was mixed with a retention improver in the same manner as in Example 3, and the sample slurry was not stirred at 3000 rpm, and the sample slurry was stirred for 10, 30, and 60 seconds. is the filler yield.

Comparative Examples 4 to 15 Comparative Examples 4 to 7 are Acurac MG1024 of Example 3.
The experiment was carried out under the same conditions as in Example 3, except that anionic polymer polyacrylamide (trade name: Organopol, manufactured by Allied Colloid Co., Ltd.) was added instead.

Comparative Examples 8 to 11 are Acurac MG102 of Example 3.
The experiment was carried out under the same conditions as in Example 3, except that cationic polymer polyacrylamide (trade name: Hydrocol 880, manufactured by Allied Colloids) was added instead of 4.

Comparative Examples 12 to t5 were conducted under the same conditions as Example 3 except that bentonite in Example 3 was removed.

The above results are shown in Table-2.

Examples 11 to 16 Examples 1 to ↓6 were carried out under the same conditions as Examples 1 to 6 except that the sample slurry of Preparation Example 2 was used.

Examples 17 to 21 are polyamine-based polymer type fixing agents (
Product name: Accurac 41 and below A manufactured by Mitsui Suiana Mitsudo Co., Ltd.
41) from 0.1 to 0.5% by weight of CGP pulp.
This is the filler yield when the amount of filler is added within the range shown in Table 3.

Comparative Examples 16 to 18 Comparative Examples 16 to 18 use 0N instead of Cato3210.
It was carried out under the same conditions as in Examples 11 to 4 except that L200 was used. The above results are shown in Table-3.

In Examples 21 to 25, a retention improver was blended with the sample slurry of Preparation Example-2 under the same conditions as in Example 18, and 3000
These are the filler yields without stirring at rpm and when stirring for 10.30 and 60 seconds.

Comparative Examples 19 to 30 Comparative Examples 19 to 22 are Accurac MG1 of Example 18.
The experiment was carried out under the same conditions as in Example 18 except that Organopol was added instead of 024.

Comparative Examples 23 to 26 are Accurac MG of Example 18.
It was carried out under the same conditions as in Example 18 except that Hydrocol 880 was added instead of 102.4.

Comparative Examples 27 to 30 were carried out under the same conditions as Example 18 except that no bentonite was added. The above results are shown in Table-4.

(Left below) From the results in Tables 1, 2, 3 and 4, it is possible to obtain paper with high filler retention and good texture, which cannot be obtained with a single type of retention improver, even under high shear force.

From the results in Tables 5, 6, 7, and 8, in the case of raw materials containing high-yield pulp, adding water-soluble aluminum salts and cationic fixing agents can provide high filler that cannot be obtained with a single type of retention improver. Paper with good yield and texture can be obtained even under high shear forces.

[Effect of the invention] Yield of pulp fine fibers and filler during high-speed papermaking in a neutral region using paper stock containing filler or paper stock containing filler and high-yield pulp. A method for producing high-quality and medium-quality neutral paper with improved freeness and operability was obtained.

Procedural amendment (spontaneous) 1.Display of the incident 2. Name of the invention Paper manufacturing method 3. Person who makes corrections Relationship with the incident Heisei 1 year Patent Application No. ↓79777

Claims (2)

[Claims] (1) A method for producing neutral paper from a paper stock containing pulp and filler, which is characterized by adding amphoteric starch, a water-swellable cationic polymer, and bentonite, and producing paper in a neutral range. Method. (2) In a method for producing neutral paper from a pulp containing 10 to 50% or less of high-yield pulp and a paper stock containing filler,
A method for producing paper, which comprises adding a water-soluble aluminum salt or a cationic fixing agent, an amphoteric starch, a water-swellable cationic copolymer, and bentonite to form paper in a neutral range.