JPH0214096A - Method for papermaking - Google Patents

Abstract

PURPOSE:To provide the title method so designed that an aqueous solution of modified cationic starch is added to a papermaking process at a specified proportion, thereby significantly improving the yield of cellulose fiber and inorganic filler in the papermaking process, enhancing water filterability, and also improving paper strength. CONSTITUTION:(A) 0.1-5.0wt.% (calculated as a solid component), based on cellulose fiber plus inorganic filler, of an aqueous solution of a modified cationic starch prepared by cooking a composition comprising (i) cationic starch prior to cooking, (ii) 0.2-15wt.%, based on the component (i), of an anionic polymer and (iii) water is added to a papermaking process followed by dehydration and drying, thus obtaining the objective paper. Furthermore, it is preferable to incorporate (B) 0.01-2.0wt.%, based an the cellulose fiber plus inorganic filler, of an anionic polymer into said papermaking process.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention aims to improve a method for producing paper containing cellulose fibers or cellulose fibers and inorganic fillers as main components, and in particular to improve the yield of cellulose fibers and inorganic fillers in the papermaking process. The present invention relates to a paper manufacturing method which significantly improves the freeness and also improves the paper strength of a dry sheet.

(Prior Art) Paper mainly composed of cellulose fibers or cellulose fibers and inorganic fillers is generally obtained by dispersing and disintegrating cellulose pulp in water, adjusting the concentration, and adding fillers and other additives as desired. The papermaking stock solution is supplied to the paper machine, and is produced through dehydration and drying processes. Improvements have been made, such as improvements in various additives such as cationic starch, and improvements in papermaking processes.

Conventionally, an acidic paper making method using aluminum sulfate as a flocculant and a fixing agent for sizing agents and an anionic organic polymer as a paper strength enhancer and a retention improver has been called ``boat fishing''. In recent years, the amount of inorganic fillers added has increased in order to reduce costs and improve paper quality, and due to the lack of high-quality pulp, the use of low-quality pulp has increased to reduce costs. The speed was increasing. In addition, the acidic papermaking method, which uses large amounts of aluminum sulfate, reduces the durability of the paper, lacks the reuse of white water, corrodes equipment, and makes it impossible to use the inorganic filler calcium carbonate, so the neutral papermaking method is increasingly being adopted. It has become. For these reasons, the methods and additives established in conventional acidic papermaking do not provide sufficient effects, so the development of retention improvers and improvement methods has been particularly desired and various proposals have been made.

The use of cationized starches to produce favorable agglomeration in papermaking and to improve paper strength has been known for some time. Japanese Patent Publication No. 55-6587 discloses a method using a combination of cationic components such as cationized starch and acrylamide copolymer with anionic components such as natural starch and carboxymethyl starch; Japanese Patent Publication No. 55-12824 discloses A method using a combination of a cationic resin emulsion and an anionic water-soluble polymer has been proposed. JP-A No. 57-51900 discloses that colloidal silica easily adsorbs to cellulose fibers and inorganic fillers and strongly aggregates with cationic substances. A paper-making method has been proposed in which a four-component agglomerated composite of fibers, inorganic filler, cationized starch, and colloidal silica is formed.

Furthermore, Japanese Patent Application Laid-open No. 191598/1983 proposes a method of improving the yield by combining a cationic polymer and bentonite. JP-A-62-15391 discloses a method of adding an acrylamide polymer having a cationic group and colloidal silicic acid, and JP-A-62-110998 discloses a method of adding an acrylamide polymer having a cationic group and colloidal silicic acid.
A method of adding colloidal silicic acid, a cationic or amphoteric polyacrylamide derivative, and cationized starch is proposed in the issue.

[Problem to be solved by the invention]

The method of using a combination of a cationic organic polymer and an anionic organic polymer as proposed in JP-A-55-6587 and JP-A-55-42824 achieves the same yields of cellulose fibers and inorganic fillers as above, and improves the yield of paper. Although it is possible to improve mechanical strength, productivity is low due to poor freeness, and paper quality such as formation deteriorates.

The combination of cationic starch and anionic silica sol proposed in JP-A-57-51900 has a good yield (high productivity due to good freeness, good paper quality such as formation, and high paper strength). However, depending on the paper-making conditions, a sufficient yield may still not be obtained.

A method of adding a combination of a cationic polymer and bentonite proposed in JP-A-62-191598, and a method of adding a combination of a cationic group-containing acrylamide polymer and colloidal silicic acid proposed in JP-A-62-15391. Both the method and the method of adding a combination of colloidal silicic acid, a cationic or amphoteric polyacrylamide derivative, and cationic starch proposed in JP-A No. 62-110998 still provide sufficient improvement in yield, drainage, etc. not achieved.

The purpose of the present invention is to sufficiently increase the yield of cellulose fibers and inorganic fillers in the papermaking process without deteriorating the paper strength and quality of the product, and to increase the production efficiency in the papermaking process and drying process by increasing freeness. The objective is to propose a paper-making method that achieves this goal.

[Means to solve the problem]

The paper manufacturing method of the present invention is a paper manufacturing method in which a paper making stock solution containing cellulose fibers or cellulose fibers and an inorganic filler is made into paper, dehydrated and then dried, and the paper making stock solution includes cationic starch and the cationic starch before wrapping. Te 0.
An aqueous solution of a modified cationic starch obtained by adding 2 to 15% by weight of an anionic polymer to water and then cumming, has a solid content of 0% relative to the total amount of cellulose fibers and inorganic filler in the papermaking stock solution. A more preferable papermaking method of the present invention is characterized in that the papermaking method of the present invention is characterized by adding cationic starch in an amount of 0.2 to 15% by weight based on the cationic starch and the cationic starch before sewing to the papermaking stock solution. An aqueous solution of modified cationic starch obtained by adding an anionic polymer to water and cooking, and an anionic polymer were added in an amount of 0.1 to 5.0% to the space between cellulose fibers and inorganic filler in the above-mentioned stock solution, respectively. Weight% and 0.
It is characterized in that it is added in an amount of 01 to 2.0% by weight.

The cellulose fibers used in the paper manufacturing method of the present invention are obtained by beating cellulose pulp, which is used in ordinary paper manufacturing, with a beater or the like. The cellulose pulp may be any of chemical pulp, mechanical pulp, thermo-mechanical pulp, and groundwood pulp. Waste paper is also used as a partial substitute for these new pulps.

The inorganic filler used in the present invention may be a normal papermaking mineral filler having a negatively charged particle surface in the papermaking stock solution, such as kaolin clay, clay, titanium oxide, anionic heavy calcium carbonate, light calcium carbonate. , fired clay, wollastonite, synthetic silica, talc, aluminum hydroxide, mineral fiber, glass fiber, perlite, etc.

Further, cationic calcium carbonate and the like can also be used together.

The papermaking stock solution used in the present invention is a liquid obtained by dispersing the above-mentioned ordinary papermaking cellulose fiber or the same and the above-mentioned inorganic filler in water. The inorganic filler is preferably added to the stock solution in an amount of 150 ft 1% or less based on the cellulose fibers in the paper of the product, but the content may be higher than this. Also in the present invention, the concentration of cellulose fibers in the papermaking stock solution may be the same as the concentration of cellulose fibers in the papermaking stock solution in a normal papermaking method. As long as the purpose of the present invention is achieved, sizing agents, fixing agents, antifoaming agents, slime control agents, dyes, and other additives may be added to the papermaking stock solution. Its pl+ is 4
~10 are applicable.

The cationic starch used in the present invention is common raw material starch,
For example, potato starch, corn starch, wheat starch, tapioca starch, their oxidized starches, hydrolyzed starches, etc., are treated with a regular cationizing agent such as quaternary ammonium chloride, quaternary ammonium sulfate, and quaternary ammonium sulfamate. It is obtained by cationization by a method such as a wet method, a dry method, an organic solvent method, etc., and is not subjected to a cushioning treatment.

The degree to which starch is cationized by these cationizing agents is generally expressed by the degree of substitution, which is defined as the ratio of the number of hydroxyl groups replaced by ether bonds to the number of glucose units in the starch molecule. be done. Preferred cationic starches used in the present invention include those having a degree of substitution of 0.01 to 0.05. Therefore, commercially available cationic starch may be used.

Examples of anionic polymers used to make the modified cationic starch used in the present invention include anionic colloidal silica, anionic colloidal silica alumina, anionic colloidal antimony pentoxide, bentonite, acpargite, synthetic mica, etc. Anionic inorganic polymers and anionic polyacrylamides, water-soluble salts of copolymers of acrylic acid and acrylic esters, such as acrylic acid and methyl acrylate, ethyl acrylate,
Sodium salts of copolymers with alkyl acrylates such as isopropyl acrylate, butyl acrylate, octyl acrylate, water-soluble salts of copolymers of acrylic acid and methacrylic acid esters, such as acrylic acid and methyl methacrylate, methacrylate ethyl acid, isopropyl methacrylate,
Examples include sodium salts of copolymers with alkyl methacrylates such as butyl methacrylate and octyl methacrylate, sodium polyacrylates, melamine formaldehyde condensate salts containing sulfonic acid groups, galactomannan, and other anionic organic polymers such as anionic resins. It will be done.

These anionic polymers are usually used as a stable aqueous dispersion such as an aqueous solution, an aqueous sol, an aqueous emulsion, or a powder, and may also be a mixture thereof. Examples of preferred anionic polymers include anionic silica aqueous sol with a particle size of 2 to 20 millimicrons, anionic antimony pentoxide aqueous sol, and a molecular weight of 2 x 1.
Spray-dry a powder, aqueous solution, and aqueous emulsion of the organic polymer described above, a mixture of an anionic silica aqueous sol or anionic antimony pentoxide aqueous sol and an anionic organic polymer aqueous solution or aqueous emulsion of about 0.03 to 2 × 106. Examples include powders obtained by this method.

The modified thione starch aqueous solution used in the present invention contains cationic starch that has not been subjected to the above-mentioned cooking treatment and 0.2 to 15.0% by weight, preferably 0.5 to 8.0% by weight based on the cationic starch. It is obtained by adding an amount of the above-mentioned anionic polymer to water and curing, and is stable. The amount of cationic starch added to this water is
Concentration in water is about 0.1-15% by weight, preferably 0.3-15%
5.0% by weight is good. The temperature of the cationic starch may be above the gelatinization temperature and below the decomposition temperature of the cationic starch, usually 100°C.
Shoes are heated at nearby temperatures. The higher the heating temperature is, the shorter the heating time is.
~20 minutes is sufficient. This tucking can be easily carried out using a conventional device such as a jet tucking machine. By this cooking, a transparent to lukewarm modified cationic starch aqueous solution is obtained.

In the paper manufacturing method according to the present invention, the above-mentioned modified cationic starch aqueous solution is added to the papermaking stock solution before papermaking, with a solid content of 0.1% relative to the total amount of cellulose fibers and inorganic filler in the stock solution.
Including adding amounts of ~5.0% by weight. A more preferable papermaking method according to the present invention includes adding the modified cationic starch aqueous solution and an anionic polymer to the papermaking stock solution.
0.1 to 5.0% by weight and 0.01 to 2.0% by weight, respectively, based on the total amount of cellulose fibers and inorganic filler in the papermaking stock solution.
This includes adding 0% by weight. The amount of anionic polymer added to the papermaking stock solution is preferably 1 to 100% by weight based on the modified cationic starch,
Particularly preferred anionic polymers include alkaline aqueous silica sol with a particle size of 2 to 20 millimicrons.

Either the modified cationic starch aqueous solution or the anionic polymer added to the above papermaking stock solution may be added to the stock solution first, but when paper is made from an acidic stock solution, the anionic polymer is added first and then the modified cationic starch aqueous solution is added. is preferable. In addition, as long as the purpose of the present invention is achieved, when adding the modified cationic starch aqueous solution to the papermaking stock solution, other cationic substances such as cationic polyacrylamide, alumina sol, basic aluminum chloride, cationic silica sol, Aluminum sulfate, basic aluminum sulfate, etc. may be added.

The modified cationic starch aqueous solution according to the present invention and the papermaking stock solution to which the anionic polymer has been added are thoroughly mixed and then fed to a paper machine by a conventional method, and the resulting wet sheet is then subjected to a dewatering process and a drying process. The product paper is manufactured through this process.

[For production]

The modified cationic starch aqueous solution significantly improves the yield of cellulose fibers and inorganic filler in the papermaking process, compared to the conventionally used solution obtained by cutting cationic starch. In addition, the yield improvement effect of this modified cationic starch aqueous solution is due to the addition of the anionic polymer in an amount of 0.2 to 15% by weight based on the cationic starch in the conventionally used solution of cationic starch subjected to kunking treatment. This is much higher than the yield improvement effect shown by the additional liquid.

The aqueous solution obtained by cooking cationic starch in water forms a colloidal aqueous solution of cationic starch, and the size of the colloidal particles is the same as that of normal papermaking stock solution, for example, 0.01% by weight. In the NaCl aqueous solution, the size is approximately 200 to 500 millimicrons, whereas the size of the colloidal particles of the modified cationic starch in the modified cationic starch aqueous solution used in the present invention is 0.01% by weight in the NaCl aqueous solution. As a result of particle size measurement using a dynamic light scattering method, it was found that the particle size was 400 to 2000 millimicrons. It is thought that stable colloidal particles with a large particle size are formed in this modified cationic starch aqueous solution, in which the cationic starch colloidal particles are cross-linked by the anionic polymer added during its preparation. It will be done. It is believed that these large-diameter colloidal particles exhibit a strong agglomerating effect on anionically charged cellulose fibers and inorganic fillers.

When preparing a modified cationic starch aqueous solution, the amount of anionic polymer added is 0.2% by weight based on the cationic starch.
Below or above 15% by weight, the resulting modified cationic starch aqueous solution does not exhibit a high yield improvement effect. The amount of anionic polymer added is 0.5 to cationic starch.
When the weight ratio is 8 to 8, a modified cationic starch aqueous solution exhibiting a particularly high yield improvement effect is obtained.

If the solid content of the modified cationic starch aqueous solution added to the papermaking stock solution is less than 0.1% by weight based on the total of cellulose fibers and inorganic filler in the stock solution, a sufficient yield improvement effect cannot be obtained in the papermaking process.

The higher the amount added is 0.1% by weight or more, the higher the yield is, but if it is added at more than 5% by weight, the paper manufacturing cost will increase, which is not preferable. Further improvement of the yield can be achieved by adding the modified cationic starch aqueous solution and the anionic polymer in a specific ratio to the papermaking stock solution. The ratio that brings about this improvement in yield is that the amount of anionic polymer is 100% by weight based on the solid content of the modified cationic starch aqueous solution.
In particular, the amount of anionic polymer is 50 to 1% by weight, and the amount of anionic polymer is 0.01 to 2.0% by weight based on the total amount of cellulose fibers and inorganic filler in the papermaking stock solution, and the modified cationic starch aqueous solution The solid content is 0.1-5.
It was found that 0% by weight.

The preferably used aqueous anionic silica sol not only improves the above-mentioned yield in the papermaking process, but also improves freeness, product paper texture, paper quality, etc.

In particular, an alkaline aqueous silica sol with a particle size of 2 millimicrons or more has good stability and is advantageous for producing paper with a constant yield and a constant paper quality. However, if the particle size of this silica sol exceeds 20 millimicrons, it tends to reduce the yield in the papermaking process. In the present invention, the effect of improving yield, freeness, etc. is good regardless of the order in which modified cationic starch and anionic polymer are added. However, when paper is made from an acidic papermaking stock solution, anionic polymer If the modified cationic starch aqueous solution is added after the addition of the modified cationic starch, the yield is highly effective. Furthermore, if the degree of substitution of the cationic starch used to prepare the modified cationic starch aqueous solution is less than 0.01, it will not bring about a sufficient yield improvement effect, and on the other hand, if it is higher than 0.05, it will become expensive and impractical. Poor.

〔Example〕

The cationic starches and anionic polymers used in Examples and Comparative Examples before packing are shown in (a) and (b) below.

(・B) Cationic starch before shoeing (1) Cationic starch obtained by cationizing potato starch with quaternary ammonium cloide to a degree of substitution of 0.03 (
C3-1).

(2) Cationic starch (C3
-2).

(3) Cationic starch (C3-3) in which corn starch is cationized with quaternary ammonium chloride to a degree of substitution of 0.03.

(b) Anionic polymer (1) Anionic silica aqueous sol (AP-1) with a sio□ concentration of 15.0% by weight, a BET particle size of 5.0 millimicrons, and a pH of 9.5.

(2) sbzos concentration 14.0% by weight, B
ET method particle size 15 millimicrons, pFI7. Anionic antimony pentoxide aqueous sol (AP-2) of O.

(3) Sodium polyacrylate concentration 30% by weight, pH
Viscosity 3600c at 7, 9, 25°C, p.

Aqueous solution of sodium polyacrylate (AP-3).

(4) Solid content concentration 35% by weight, p) 1B, 5,25°C
An aqueous sodium salt solution of a sulfonic acid group-containing melamine formaldehyde condensate (A P
-4).

(5) Powder of sodium salt of sulfonic acid group-containing melamine formaldehyde condensate containing 7% by weight of water (AP
-5).

(6) Anionic polyacrylamide powder (AP-
6).

(7) Add a caustic soda aqueous solution to the anionic antimony pentoxide aqueous sol of AP-2 to make p119, then add the sodium polyacrylate of AP-3 to this,
Sighs/sodium polyacrylate weight ratio is 80
/20 powder (AP-7) obtained by spray drying the mixture.

(8) Mix 80 parts by weight of the anionic antimony pentoxide aqueous sol of AP-2 as sb, o and 20 parts by weight of the sodium salt aqueous solution of the sulfonic acid group-containing melamine formaldehyde condensate of AP-4 as solid content. After that, the powder obtained by spray drying (AP-8
).

(9) The anionic silica aqueous sol of AP-1 was
Powder (AP-9) obtained by mixing 33 parts by weight (ng) and 67 parts by weight (solid content) of the sodium salt aqueous solution of the sulfonic acid group-containing melamine formaldehyde condensate of AP-4 and spray drying the mixture. .

Example 1 This example demonstrates the preparation and measured properties of a modified cationic starch aqueous solution, a cationic starch cooking liquid and a mixture of this cooking liquid and an anionic polymer for addition to a papermaking stock solution.

(B) Preparation of modified cationic starch aqueous solution To 1.0 g of the cationic starch from C3-1 to C3-3 before cooking, add an anionic polymer and water in the weight percent amount shown in Table 1 based on the cationic starch. 200 g of the resulting mixture was stirred in a glass flask for 1 hour.
After heating at 00''C for 20 minutes, cooling, and adding water for concentration adjustment, a modified cationic starch aqueous solution with an initial cationic starch concentration of 0.5% by weight was obtained (solutions Nα1 to Nα1 in Table 1). 25).

(b) Preparation of cationic starch cooking liquid C3-1 above
~C3-3 cationic starch 1. 200 g of the mixture obtained by adding water to Og was heated in the same manner as in (a) above, then cooled and the concentration was adjusted to make cationic starch with an initial cationic starch concentration of 0.5% by weight. A liquid was obtained (first surface liquid Nα26-28).

(c) Preparation of a mixture of cationic R-type cooking liquid and anionic polymer Cationic starch of C3-1 1. 200 g of the mixture obtained by adding water to Og was heated in a glass flask with stirring at 100° C. for 20 minutes, cooled, and added with the anion of AP-1 in the weight % amount shown in Table 1 based on the cationic starch. By adding aqueous silica sol and water for concentration adjustment, the initial cationic starch concentration was 0.5% by weight.
A mixture was obtained (Table 1 Liquid No. 29).

(d) Measurement of properties Regarding the liquids obtained in (a), (b) and (c) above,
Table 1 shows the results of measuring the viscosity and pH at 25°C.

Furthermore, after adding a small amount of the above solution to a 0.01% by weight NaCl aqueous solution, the modified cationic starch and cations in the solution were measured using a dynamic light scattering particle size measuring device called N4 manufactured by Coulter Co., Ltd. The results of measuring the diameter of starch particles are
Shown in the table.

However, properties of liquid Nos. 23 to 25 were not measured because aggregates were formed in the liquid. Also, liquid No. 1~
No. 22 and No. 27 to No. 28 had a slight temperature in appearance, and No. 26 and Na No. 29 were transparent.

Table 1 Example 2 In this example, after preparing a beaten pulp slurry, an acidic papermaking stock solution was prepared by adding required additives to the slurry, and the modified cationic starch aqueous solution obtained in Example 1 was further added to this. After adding the above, paper was made and the yield of fine components was measured.

(a) Preparation of pulp slurry 90 g of softwood bleached kraft dry pulp and 270 g of hardwood bleached kraft dry pulp were added to 25 kg of water and left to stand day and night. ) is 350
mj! A pulp slurry was prepared by beating the pulp to give a pulp slurry.

(b) Preparation of papermaking stock solution Add aluminum sulfate aqueous solution, rosin sizing agent, kaolin (China clay) as a fixing agent to the above pulp slurry,
Add water and sulfuric acid, pulp concentration 0.35% by weight, kaolin 0.15% by weight, aluminum sulfate (18 hydrate) 0
．． 0035% by weight, rosin sizing agent 0.0015% by weight
A papermaking stock solution having a kaolin/pulp ratio of 43% by weight and a pH of 4.5 was prepared.

(c) Measuring method of yield of fine components The yield is measured using dynamic drainage di+
(Britt-Jar) Magazine Tappi as a test method
Written in! ! (Britt, W.: Tappi,
56 (10), 46-50 (1973), and in the following manner.

- Total concentration of pulp and filler in paper stock solution C weight %
Calculate accurately.

■ The papermaking stock solution, which was adjusted by adding a surfactant to make it easier for fine components to pass through, was passed through a 200-mesh wire mesh, and the weight of the components that did not pass through was measured. The ratio F weight % of the total fine components passing through the wire mesh to the total pulp content and filler content is calculated in advance. The concentration of all fine components in the papermaking stock solution is calculated as CxF/100% by weight.

■Pour 500 mj2 of stock solution into a jar and
A predetermined amount of a modified thionic starch aqueous solution is added to this while stirring at a speed of rpm, and timing is started. After 45 seconds, drainage is started and white water is collected for 30 seconds. If the anionic polymer is added to the papermaking stock solution after adding the modified cationic starch, add the modified cationic starch to the papermaking stock solution and start timing,
After 0 seconds, the anionic polymer is added, and after another 15 seconds, drainage is started and white water is collected for 30 seconds. If the order of addition is reversed, the modified cationic starch is added 40 seconds after the start of timing, and after another 5 seconds, drainage is started and white water is collected for 30 seconds.

Measure the volume of the collected white water and set it as Xll1l.

In addition, by using a 200-mesh wire mesh and adjusting the diameter of the drain port, the amount of water drained in 30 seconds can be approximately 100+.
nj! I made it so that

(2) Prepare a quantitative filter paper with a dry weight Wl g, filter the white water collected in (2) through this filter paper, dry the filter paper, and then weigh it to obtain Wzg. Wz-Wl represents the weight of fine components in the white water Xme that has passed through the wire mesh.

■ The ratio of fine components retained on the wire mesh to the total fine components in the paper stock solution, that is, the yield of fine components (weight %), is calculated using the following formula: Yield of fine components (weight %)
) − given by XF.

(d) Measurement of yield of fine components and results The ratio F of the total fine components in the papermaking stock solution prepared in (b) above was 35% by weight. Aqueous solutions No. 1 to 22 and No. 26 to 2 prepared in Example 1 were added to 500 g of this papermaking stock solution.
9 was added, and the yield (wt%) of fine components was measured using the yield measurement method described in (c) above.
The results shown in the table were obtained. Examples using liquids No. 1 to 21 are examples, and examples using liquids No. 22 and No. 26 to 29 are comparative examples. The yield of fine components in the papermaking stock solution itself was 5.8% by weight.

The Nα22 solution is a solution in which 0.1% by weight of an anionic polymer is added to the cationic starch when preparing modified cationic starch, but this added amount of anionic polymer does not have a sufficient yield improvement effect. I understand. Also, Sou 2
Solution No. 9 is a mixed solution in which an anionic polymer is added to a cationic starch cooking solution, but this solution also does not have a yield improvement effect.

It is recognized that the yield is significantly improved when Nα1-21, which is an aqueous solution of modified cationic starch, is used, compared to the yield when Nα26-28, which is a cationic starch cooking liquid, is used.

Example 3 In this example, the paper stock prepared in Example 2
After adding 5 g each of the aqueous solutions of Nα1 to 22 and 26 to 29 prepared in Example 1 to 500 g, anionic polymer AP-1 was diluted with water to give a SiO□ concentration of 0.5% by weight. Add 1.5 g of the prepared solution and proceed to (c) of Example 2.
This is an example in which the papermaking yield was measured using the method described in . No,
Examples using liquids No. 1 to 21 are examples, and examples using liquids No. 22 and Nα26 to 29 are comparative examples.

The results are shown in Table 2, and it can be seen that all the examples of the present invention had a significant yield improvement effect.

Example 4 In this example, the addition of the aqueous solution in Example 3 was carried out after the addition of the anionic polymer, and the method for measuring the yield of fine components described in Example 2 was also slightly modified. That is, anionic polymer AP-1 was diluted with water to 500 g of the paper stock solution prepared in Example 2, and the SiO□ concentration was 0.5% by weight.
Add 1.5 of the solution adjusted to Example 1 after 40 seconds.
Nos. 1 to 22 and Nos. 26 to 29 prepared in
Drainage was initiated 5 seconds after the addition of 5 g of each aqueous solution. Other conditions were the same as above, and the results are shown in Table 2. However, Nα1. No, 2°No, 13
In the examples using solutions No. 22 and No. 29, the anionic polymer AP-1 added to the papermaking stock solution
The amount of SiO□ was adjusted to be 0.3% by weight based on the total amount of cellulose fibers and filler.

The results in Table 2 show that all of the Examples of the present invention showed a remarkable yield improvement effect, and that the addition method of Example 4 gave an even higher yield than the addition method of Example 3. It shows.

Example 5 Heavy calcium carbonate, water and sulfuric acid were added to the pulp slurry prepared in Example 2 (a) to give a pulp density of 0.3.
5% by weight, heavy calcium carbonate concentration 0.15% by weight, p
A neutral papermaking stock solution of H7,1 was prepared. The proportion F of the total fine components in this stock solution was 35% by weight. Further, the yield of fine components in this stock solution itself was 21.3% by weight.

Next, the aqueous solution Nα1. prepared in Example 1 was added to 500 g of this papermaking stock solution with stirring. Nα7-11. Ni113, Nα
15. Nα17. Nα20-22 and No.

Add 5 g of each of Nos. 26 to 29, and then add 1.5 g of diluted solution of anionic polymer AP-1 (SiO□0.5% by weight).
In addition, the yield of fine components was measured in the same manner as in Example 2. The results are shown in Table 2, and the comparison example Nα22
and Nα of the example, than when using a solution with Nα of 26 to 29.
α1. No, 7~11°No, 13. No, 15.
In the examples using Nα17 and Nos. 20 to 21, a remarkable improvement in yield is observed.

Second surface liquid No. Example 2 Example 3 Example 4 Example 5
In the Examples, freeness was tested.

A papermaking stock solution having a total concentration of pulp and filler components of 0.3% by weight was prepared by diluting the papermaking stock solution prepared in Example 2 with water.
NO,1,Nα prepared in Example 1 under stirring at 0 rp.
7-8. No, 13. No, i°5. No, 17°No
, 21-22 and N (add 6g each of solutions 126-29,
After 30 seconds, a diluted solution of anionic polymer AP-1 (S
iO2 concentration 0.5%) was added, and the freeness (m 1.) was immediately measured at 20°C using a C3F tester. The amount of anionic polymer added is 0% by weight relative to the total amount of pulp and filler.

0.1 wt%, 0.3 wt% and 0.5 wt%.

The results are shown in Table 3. Comparative examples Nα22 and No.
, Nos. 26 to 29 were used, the freeness was significantly improved in all cases when the other above-mentioned liquids of Examples were used. It has also been shown that adding a modified cationic starch aqueous solution and an anionic polymer to the papermaking stock solution further improves freeness. The freeness of the papermaking stock solution itself was 466 mN.

Table 3 [Effects of the Invention] In the papermaking stock solution to which the modified cationic starch aqueous solution is added according to the present invention, composite aggregates of cellulose fiber-mineral filler-modified cationic starch are formed, and the modified cationic starch aqueous solution and anionic In the papermaking stock solution to which polymer is added, composite aggregates of cellulose fibers, inorganic filler, modified cationic starch, and anionic polymer are formed.
All of these composite aggregates have stronger cohesive force than the conventionally used composite aggregates of cationic starch or anionic polymers, and have sufficient resistance against the effects of electrolytes, shearing forces, etc. in the stock solution. It exhibits toughness and stably improves yield and freeness in the papermaking process. This improvement in yield and drainage improves the productivity of paper products, reduces white water treatment costs, increases the efficiency of white water reuse, reduces thermal energy in the drying process, and improves the durability of paper making machines. It brings great benefits to the paper production process, such as improving the paper production process. Furthermore, the product paper obtained by the paper manufacturing method of the present invention has good qualities such as paper strength, paper quality, and texture.

In addition, the modified cationic starch aqueous solution used in the present invention is
．． In addition to being used in the paper manufacturing method described in F, it can also be advantageously used as a flocculant for producing inorganic fiber paper, inorganic fiber molded articles, etc., and as a flocculant in other fields. Since the modified cationic starch aqueous solution used in the present invention has a high cohesive force, even if cationic starch with low performance is used, the performance can be improved by preparing it as a modified cationic starch aqueous solution, and these cationic starches can also be used as raw materials. Can be used.

The use of the modified cationic starch aqueous solution used in the present invention improves the quality of the paper product, so if it is sufficient to produce paper with the same quality as conventional paper, it is possible to improve the quality of the paper product. Part or all of it can be replaced by cellulose fibers derived from waste paper.

Sender: Nissan Chemical Industries, Ltd.

Claims (4)

[Claims] (1) In a paper manufacturing method in which a papermaking stock solution containing cellulose fibers or cellulose fibers and an inorganic filler is made into paper, dehydrated, and then dried, the papermaking stock solution contains cationic starch before cooking and 0.2% of the cationic starch. ~15% by weight
An aqueous solution of modified cationic starch obtained by adding anionic polymer in an amount of 0.1 to 5.0% as a solid content based on the total amount of cellulose fibers and inorganic filler in the papermaking stock solution. A papermaking method characterized in that an amount of 0% by weight is added. (2) In a paper manufacturing method in which a papermaking stock solution containing cellulose fibers or cellulose fibers and an inorganic filler is made into paper, dehydrated, and then dried, the papermaking stock solution contains cationic starch before cooking and 0.2% of the cationic starch. ~15% by weight
An aqueous solution of modified cationic starch obtained by adding an amount of anionic polymer to water and cooking the anionic polymer in an amount of 0.1 to 0.1 to 0.1 to the total amount of cellulose fiber and inorganic filler in the above-mentioned stock solution, respectively. 5.0% by weight
A papermaking method characterized by adding 0.01 to 2.0% by weight of . (3) The anionic polymer is anionic colloidal silica, anionic colloidal antimony pentoxide, bentonite, anionic polyacrylamide, a water-soluble salt of a copolymer of acrylic acid and an alkyl ester of acrylic acid, acrylic acid and methacrylate. According to claim (1) or claim (2), which is a water-soluble salt of a copolymer with an alkyl ester of an acid, sodium polyacrylate, a sulfonic acid group-containing melamine formaldehyde condensate salt, or a mixture thereof. Paper making method. (4) The degree of substitution of cationic starch before cooking is 0.01
The paper manufacturing method according to claim (1) or claim (2), which contains a quaternary ammonium group in the range of 0.05 to 0.05.