JPH0274695A - Paper making method - Google Patents

Abstract

PURPOSE:To improve yield of cellulose and inorganic filler and simultaneously contrive improvement of drainage properties and production efficiency by adding a specific anionic silica sol and cationic group-containing polymer to a papermaking dope. CONSTITUTION:An anionic silica gel having nearly uniform thickness within the range of 5-20mmu and having fine and long shape stretched on only one plane and 40-300mmu particle size by dynamic light scattering method and cationic group-containing polymer are added to a papermaking raw material containing a cellulose fiber or cellulose fiber and inorganic filler. In the addition amount thereof, SiO2 of silica sol is used at a ratio of 0.1-10 pts.wt. based on 1 pts.wt. polymer and the polymer is used at an amount of 0.05-10.0wt.% based on the total amount of cellulose fiber or the cellulose fiber and inorganic filler.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is directed to improving a method for producing paper containing cellulose fibers or cellulose fibers and inorganic fillers as main components, and in particular improving the yield of cellulose fibers and inorganic fillers in the papermaking process. Concerning a paper manufacturing method.

<Prior art> Improvements in paper manufacturing methods include improving equipment, improving various additives such as cationic starch, and improving the papermaking process with the aim of improving the yield of cellulose fibers and fillers, improving paper strength, and improving productivity. Improvements have been made.

Conventionally, acidic papermaking methods have been common in which aluminum sulfate is used as a flocculant and a fixing agent for sizing agents, and anionic organic polymers are used as paper strength enhancers and retention improvers.

In recent years, the amount of inorganic filler added has been increased to reduce costs and improve paper quality, and the use of low-quality valves and waste paper has increased to compensate for the lack of high-quality pulp or to reduce costs. In addition, efforts have been made to increase the speed per second in order to further improve productivity.

In addition, acid papermaking methods that use large amounts of aluminum sulfate are often replaced by neutral papermaking methods to avoid problems such as decreased paper durability, inability to reuse white water, corrosion of equipment, and inability to use calcium carbonate as an inorganic filler. It has come to be. 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.

JP-A No. 55-6587 discloses a method in which a cationic component such as a cationic starch or an acrylamide copolymer is combined with an anionic component such as natural starch or carboxymethyl starch.
In this issue, a method using a cationic resin emulsion and an anionic water-soluble polymer in combination is proposed. JP-A No. 57-51900 discloses that colloidal silica easily adsorbs to cellulose fibers and inorganic fillers (and strongly aggregates with cationic substances, so by using this together with cationic starch and anionic silica sol) ,
A paper-making method has been proposed in which a four-component agglomerated composite of cellulose fibers, inorganic filler, cationic starch, and colloidal silica is formed.

JP-A-62-191598 also proposes a method of improving the yield by adding a combination of a cationic polymer and bentonite. JP-A No. 62-15391 describes a method of adding an acrylamide polymer having a cationic group and colloidal silicic acid, and JP-A No. 62-1109
No. 98 proposes a method of adding colloidal silicic acid, a cationic or amphoteric polyacrylamide derivative, and cationic starch.

<Problems to be Solved by the Invention> In the method of using a combination of a cationic organic polymer and an anionic organic polymer as described in JP-A-55-6587 and JP-A-55-12824, cellulose fibers and Although it is possible to improve the yield of inorganic filler and the paper 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 No. 57-51900 has a good yield and good drainage, resulting in high productivity (although the paper quality such as formation is good and the paper strength is high, 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-62-110998 still achieve sufficient improvement in yield and freeness. Not done.

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 improve the production efficiency in the papermaking process and drying process by increasing freeness. The objective is to provide a papermaking method that can be improved.

<Means for Solving the Problems> The paper manufacturing method of the present invention is a paper manufacturing method in which a paper manufacturing solution containing cellulose fibers or cellulose fibers and an inorganic filler is made into paper, dehydrated, and then dried. 2
The particle size is approximately uniform within the range of 0 mm and has an elongation in only one plane, and the particle size measured by dynamic light scattering is 4.
An elongated anionic silica sol having a size of 0 to 300 millimicrons and a cationic group-containing polymer are added to the SiO20.1 of the silica sol per 1 part by weight of the polymer.
The polymer is added to a ratio of 0.05 to 10.0 parts by weight based on the total amount of cellulose fiber or the inorganic filler in the papermaking stock solution.

The cellulose fibers used in the papermaking method of the present invention are those obtained by beating cellulose pulp, which is used in ordinary papermaking, with a beater or the like. Cellulose pulp is chemical pulp,
Any of mechanical pulp, thermo-mechanical pulp, groundwood pulp, etc. may be used. Waste paper can also be used as a partial replacement for these new pulps.

The inorganic filler used in the present invention may be any ordinary mineral filler for papermaking, such as kaolin clay, clay, titanium oxide,
Examples include heavy calcium carbonate, light calcium carbonate, calcined clay, wollastonite, synthetic silica, talc, aluminum hydroxide, mineral fiber, glass fiber, and perlite. All of these fillers, except aluminum hydroxide, have an anionic surface at the pl+ conditions used. Heavy calcium carbonate is weakly alkaline as it is and has cationic properties, but when it is neutralized with carbonic acid and made alkaline, it shows anionic properties and therefore is anionic under papermaking conditions. Calcium carbonate dispersed with a dispersant such as sodium polyacrylate is also anionic.

The inorganic filler is 15% of the cellulose fiber in the product paper.
It is preferable to add it to the stock solution so that it is 0% by weight or less, but the content may be higher than this. The appropriate pH of the papermaking stock solution is 4 to 10.

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 invention is achieved,
Additives such as fixing agents, sizing agents, antifoaming agents, slime control agents, dyes, and pigments may be added to the papermaking stock solution.

The cationic group-containing polymer used in the present invention is an organic high molecular weight polymer that is water-soluble or colloidally dispersible in water, and has a cationic group such as a quaternary ammonium cation group in its molecule. It is something that you have.

The polymer may also contain anionic groups, but is sufficiently cationic to exhibit electrical attraction to negatively charged particles such as cellulose fibers, inorganic fillers, and anionic colloidal silica particles in water. It has a group of Such polymers may be those conventionally used and are easily available as commercial products.

Examples of such cationic group-containing polymers include cationic or amphoteric starches.

These starch derivatives include potato starch, corn starch, wheat starch, tapioca starch,
Those which can be easily produced from such oxidized starch, hydrolyzed starch, etc. by a conventional method, for example, by reaction with quaternary ammonium chloride, and which contain a cationic group with a degree of substitution of 0.01 to 0.05 are preferred. Further, cationic or amphoteric guar gum, cationic galactomannan, etc. can also be used.

Further examples include cationic or amphoteric polyacrylamide, cationic or amphoteric modified polyacrylamide, cationic polyethyleneimine, cationic polyamide polyamine-epichlorohydrin resin, cationic urea formaldehyde resin, and the like. These synthetic resins preferably have a molecular weight of about 10,000 to 10 million, and preferably have a cationic group with a degree of substitution of about 0.02 to 0.5. A cationic group can be easily introduced into a polymer molecule by using an amide group such as a Hoffman reaction or a Mannich reaction.
Introducing an anionic group involves a carboxylation reaction,
This can be easily carried out by sulfomethylation reaction, etc., but it is convenient to use commercially available industrial products as polymers containing these cationic groups.

The elongated anionic silica sol used in the present invention has colloidal silica particles that have a substantially uniform thickness within the range of 5 to 20 mμ and elongate only in one plane, and are dynamic. It has an elongated shape with a particle diameter of 40 to 300 mμ as determined by the optical scattering method. The shapes of the many colloidal silica particles present in this sol are not limited to the same shape, but they all have an elongated shape, some are almost straight, some are bent, some have branches,
Although they have rings, most of them are bent or branched.

The silica sol used in the present invention is the following (a).

Each step of (b) and (C), (a) a water-soluble colloid of activated silicic acid containing 2 to 6 weight percent as SiOt, a water-soluble calcium salt;
A step of adding and mixing an aqueous solution containing a magnesium salt or a mixture thereof in an amount such that the weight ratio of CaO, MgO, or both of them is 1500 to 8500 ppm to 5 iOz of the activated silicic acid, (b) by step (a) An alkali metal hydroxide, an organic base, or a silicate thereof is added to the resulting aqueous solution using SiO
□/M, O (However, SiO□ represents the total amount of silica derived from the above-mentioned active silicic acid and silica of the above-mentioned silicate, and M represents the above-mentioned alkali metal atom or organic base molecule.)
A step of adding and mixing so that the molar ratio is 20 to 200, and (C) adding the mixture obtained in step (b) to 60 to 200.
It is produced as an alkaline aqueous silica sol by a method including heating at 150°C for 0.5 to 40 hours. An acidic silica sol can be produced by cation exchange of this alkaline aqueous silica sol. The silica sol having the above elongated shape has a pH of 2
-11 can be used, but alkaline sols with good storage stability are preferred.

In place of a part of the elongated anionic silica sol, or together with it, an anionic polymer, for example,
Conventionally known polymers such as anionic polyacrylamide, copolymers of acrylic acid and acrylic esters, and sulfonic acid group-containing melamine formaldehyde condensates can also be used.

In the papermaking method of the present invention, the amount of the cationic group-containing polymer added to the papermaking stock solution is 0.05% based on the total amount of cellulose fiber or the inorganic filler in the stock solution.
~1000% by weight is suitable.

Further, the amount of the anionic silica sol added is set at a weight ratio of Sin to the amount of the cationic group-containing polymer.
, and preferably 0.05 to 5.0% by weight based on the total amount of cellulose fiber or the inorganic filler in the above-mentioned stock solution.

The paper produced by the paper manufacturing method of the present invention is produced by adding the above-mentioned cationic group-containing polymer and an elongated anionic silica sol, and making a paper stock solution in which the cationic group-containing polymer and elongated anionic silica sol are thoroughly mixed by a normal paper-making method, followed by dehydration and drying. It can be easily obtained through a process.

<Function> According to the present invention, the anionic silica sol having a unique shape added to the papermaking stock solution is combined with the added cationic group-containing polymer in the papermaking stock solution by cellulose fibers, cationic polymer, and anionic silica sol. It works to form a strong aggregate consisting of particles or a strong aggregate consisting of cellulose fibers, inorganic filler, cationic polymer, and anionic silica particles. These aggregates exhibit high resistance to the presence of electrolytes in the papermaking stock solution and the action of shearing force from the solution, and are reliably held on ordinary papermaking nets to prevent cellulose fibers added to the papermaking stock solution. , the yield of inorganic fillers, etc. is significantly improved. Compared to the conventionally used spherical silica sol, the unique elongated shape of the elongated silica sol is considered to have an advantageous effect on the formation of strong aggregates during the formation of the aggregates.

If the amount of the cationic group-containing polymer added to the papermaking stock solution is 0.05% by weight or less based on the total amount of cellulose fibers or the inorganic filler in the stock solution, cellulose fibers,
Sufficient yield of fillers etc. is not achieved. Although the yield increases as the amount of the cationic group-containing polymer increases, adding a large amount of 1% by weight or more increases paper production costs and also causes deterioration of paper quality.

If the amount of the elongated anionic silica sol used in combination with the cationic group-containing polymer is less than 0.001 parts by weight as SiO It is hardly effective, and when the amount of silica sol added is up to 10 parts by weight of SiO
After all, adding a large amount increases the production cost of paper. The practically preferable addition amount is 0.05 to 5.0% by weight based on the total amount of cellulose fiber or the inorganic filler, assuming 5 int.

<Example> [Preparation of elongated anionic silica sol (A)] Commercially available JIS No. 3 sodium water glass (SiO□/N
azO molar ratio 3.22, Sin! 28.5% by weight) was diluted to a 5iOz concentration of 3.6% by weight, and then passed through a column packed with a cation exchange resin (Amberlite 120B) to obtain 5t (h concentration of 3.56%). %,
A colloidal aqueous solution of activated silicic acid having a pH of 2.81 and a conductivity of 730 as/cm was obtained. 2000 g of this colloidal aqueous solution of activated silicic acid was placed in a glass container, and 8.0 g of a 10% by weight aqueous calcium chloride solution was added at room temperature with stirring.
After 0 minutes, add 10% sodium hydroxide aqueous solution12.
0 g was added at room temperature with stirring. The pH of this mixed solution was 7.6.5 iOt/NatO molar ratio of 80.

Next, this mixed solution was charged into a stainless steel autoclave and heated at 130°C for 6 hours with stirring to form SiO23,5.
A silica sol of 2% by weight, a sio□/NazO titration molar ratio of 101, and a pH of 9.64 was obtained. Next, this silica sol was concentrated using an ultrafiltration device to obtain a concentrated silica sol (A) having a 5iOz concentration of 20%. This sol contains no free calcium ions, has a specific gravity of 1.129, and a pH of 9.2.
4. Viscosity 84c, p, 5iOz 20.2%, 5iQ
z/ Na10 titration method molar ratio 124, Ca00.113
Weight %, C1” 190ppm, 5O4-20pp
It was m. Moreover, the colloidal silica particles in this sol are elongated particles as observed by electron microscopy, and the thickness is 10
~14 mμ. The particle size determined by dynamic light scattering was 84.5 mμ, and the BET particle size was 12.1 mμ.

[Preparation of elongated anionic silica sol (B)]

Colloidal aqueous solution of the above activated silicic acid (SiO□3.56%,
pH 2,81) 2000g was placed in a glass container, 4.8g of a 10% aqueous magnesium chloride solution was added thereto with stirring, and then 13.5g of a 10% by weight aqueous sodium hydroxide solution was added with stirring. , S
A mixed solution with a tow/NazO molar ratio of 70 and a pH of 7.82 was obtained. Next, this was heated at 100° C. for 5 hours, and then this sol was concentrated to a silica concentration of 10 weight SiO□ using an ultrafiltration device, thereby obtaining a silica sol (B). The obtained sol has a specific gravity of 1.051, a pl+9.10, and a viscosity of 12.
c, p, SiO□10.2% by weight, 5t02/Naz
The molar ratio according to the O titration method was 95, and the MgO was 280 ppm. The colloidal silica particles of this sol were found to have an elongated shape and a thickness of 4 to 6I11μ when observed using an electron microscope. Particle diameter determined by dynamic light scattering method is 154 mμ, B
The ET particle size was 6.2111μ.

[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 after being left for day and night, this was milled in an experimental beating machine until the Canadian Standard Freeness (C3F) reached 350 mj! The pulp was beaten to give a pulp slurry.

Example 1 Aluminum sulfate aqueous solution, rosin sizing agent, kaolin (China clay), water and sulfuric acid aqueous solution were added as a fixing agent to the above beaten pulp slurry to give a pulp density of 0.35.
% by weight, 0.15% by weight of kaolin, aluminum sulfate (
18 hydrate) 0.0035% by weight, rosin sizing agent 0
．． A papermaking stock solution with a kaolin/pulp ratio of 43% by weight and a pH of 4.5 was prepared.

The fine component of the stock solution was 35% by weight. Next, 5.0 g of a 0.5% by weight aqueous solution of cationic starch obtained by cooking cationized potato starch with a degree of substitution of 0.04 at 100° C. for 20 minutes was added to 500 g of the above papermaking stock solution with stirring, and then a long and narrow shape was added. After adding 1.5 g of a diluted solution of silica sol (A) (diluted to a silica concentration of 0.5% by weight), the yield of fine components was measured by the following method.

In this example, cationic starch/(pulp + filler)
The ratio is 1.0% by weight, and the anionic colloidal silica with elongated shape/(pulp+filler) ratio is 0.3% by weight. The measurement results are shown in Table 1.

[Method for measuring yield of fine components]

Dynamic drainage jar (Br1tt-Jar)
) test method (Brltt, K, W,:Tappi,
56 (10) 46-50° 1973) as follows.

(1) Collect 500g of papermaking stock solution in a jar,
Stirring is carried out at rpm. Accurate dry solids content in paper stock solution (
Pulp + inorganic filler) concentration is set to 0%.

(2) Add an aqueous solution of a cationic group-containing polymer to this and start timing.

(3) Add anionic silica sol after 30 seconds.

(4) Start draining after another 15 seconds and collect white water for 30 seconds. The amount of white water during this time is defined as X mj2.

(A 200-mesh wire mesh was used, and the hole diameter of the glass tube was adjusted so that the flow rate for 30 seconds was approximately 100 mf!) (5) This white water was dried at 105°C in advance. weight(
Quantitative filter paper (Toyo Roshi Model 5C) for measuring W+g)
filter, dry at 105°C, and measure the weight (filter paper + fine components). Let this weight be W2g.

(6) All fine components in the original papermaking stock solution (fine valves +
The weight percent of the inorganic filler (inorganic filler) is determined in advance by another method. This value is defined as F%.

(7) The yield of fine components is calculated using the following formula.

Yield of Fine Component (% by Weight)

Example 2 Ground calcium carbonate, water and an aqueous sulfuric acid solution were added to the above beaten pulp slurry to obtain a pulp concentration of 0.35% by weight, a ground calcium carbonate of 0.15% by weight, a ground calcium carbonate/pulp ratio of 43% by weight, and A papermaking stock solution with a pH of 7.10 was prepared. The fine component of the stock solution was 35% by weight.

Next, 500 g of this papermaking stock solution was mixed with a degree of substitution of 0.04 while stirring.
Add 5.0 g of a 0.5% by weight aqueous solution of cationic starch obtained by heating the cationized potato starch at 100'C for 20 minutes, and then add anionic silica sol (A) having an elongated shape to a silica concentration of 0.5. After adding 1.5 g of the diluted product to the weight ratio, the yield of fine components was measured. Anionic silica sol (
Regarding B), the yield was measured in the same manner, and the results are shown in Table 1.

Example 3 In place of the cationic starch solution in Example 2,
The yield was measured in the same manner as in Example 2, except that 1.0 g of a cationic polyacrylamide aqueous solution (concentration 0.5%) with a degree of substitution of 0.15 was added. The results are shown in Table 1.

Comparative Examples 1 and 2 As Comparative Example 1, the yield of fine components was measured in the same manner as in Example 1 except that neither cationic starch nor anionic silica sol was added, and it was found to be 11.8% by weight.

Similarly, as Comparative Example 2, the yield was measured according to Example 2 without adding either cationic starch or anionic silica sol, and it was found to be 25.7% by weight.

Comparative Example 3 The yield was measured in the same manner as in Example 1 except that cationic starch was added but anionic silica sol was not added, and the yield was 24.1% by weight.

Comparative Examples 4 to 6 Conventionally used commercially available spherical silica sol (C) (
Specific gravity 1.129, pH 9.78, viscosity 2.5 c, p
,,5iOz 20.1% by weight, sio□/NazO titration method molar ratio 90, BET method particle size 12.0 mμ, dynamic light scattering method particle size 23 mμ) and the same commercially available spherical silica sol (D) (specific gravity 1.132 , pH 9.32, viscosity 4.2
c, p, 5t (h 20.2% by weight, sio, /Na
zO titration method molar ratio 54, BET method particle size 5.2 mμ,)
The yields of Comparative Example 4 were prepared in the same manner as in Example 1, the yields of Comparative Example 5 were determined in the same manner as in Example 2, and the yields of Comparative Example 6 were determined in the same manner as in Example 3. Measurements were taken. The results are shown in Table 1.

table Ma As a result, the results shown in Table 2 were obtained.

Comparative Example 7 The yield was measured in the same manner as in Example 4, except that spherical silica sols (C) and (D) were used instead of the elongated anionic silica sol. The results are shown in Table 2.

Table 2 Silica sol (A) used in Example 1 and Comparative Example 4, Example 2 and Comparative Example 5, and Example 3 and Comparative Example 6
From the comparison of case C) and the comparison of cases CB) and (C゛), it is recognized that the yield is significantly improved when an elongated silica sol is used instead of the conventional spherical silica sol.

Example 4 A liquid was prepared by diluting each of the elongated anionic silica sols (A) and (B) with water to a silica concentration of 0.5% by weight, and these were diluted with 5iOz based on the total amount of pulp and filler.
．． Example 1 except that amounts of 1% by weight and 0.5% by weight were used.
By measuring the yield in the same manner as above and comparing Example 4 and Comparative Example 7, it can be seen that the elongated silica sol significantly improves the yield both when the amount of silica sol added is small and when it is large. .

Example 5 A papermaking stock solution having the same composition as that used in Example 1 was prepared, except that the total concentration of pulp and inorganic filler was adjusted to 0.3% by weight. The freeness of 1000 g of this stock solution was measured at 20°C using a Canadian Standard Freeness Tester under stirring at 100°rpm, and it was found to be 510mj.
! Met.

Next, the same procedure as in Example 1 was carried out, except that the elongated silica sol (A) was added to the papermaking stock solution in an amount of 0.1% by weight (5 tots) based on the total amount of pulp and inorganic filler in this stock solution, and Immediately after this addition, freeness was measured in the same manner as above. The results are shown in Table 3.

Furthermore, the freeness was measured in the same manner as above when the amount of the silica sol (A) added was increased to 0.3% by weight and 0.5% by weight, and the results shown in Table 3 were obtained.

This time, the elongated silica sol (B) was used instead of the silica sol (A), and the amounts of SiO□ added were 0.1% by weight, 0.3% by weight, and 0.5% by weight as above.
The freeness was measured and the results shown in Table 3 were obtained.

Comparative Example 8 A papermaking stock solution in which 1.0% by weight of cationic starch was added to the papermaking stock solution prepared in Example 5 based on the total amount of pulp and inorganic filler in this stock solution, but no anionic silica sol was added. The freeness was measured in the same manner as in Example 5 and found to be 5331I11.

Comparative Example 9 In the case where the spherical silica sols (C) and CD) were used instead of the elongated silica sol, the freeness was measured in the same manner as in Example 5, and the results shown in Table 3 were obtained.

Comparing Example 5 and Comparative Example 9 above in the table, it is recognized that the freeness in the papermaking process can be significantly improved by using an elongated silica sol instead of the conventionally used spherical silica sol.

<Effects of the Invention> According to the paper manufacturing method of the present invention in which paper is made after adding a cationic group-containing polymer and an elongated anionic silica sol to a paper making stock solution, the yield of pulp or the pulp and inorganic filler in the paper making process is improved. Freeness can be significantly improved. This improvement results in reduced white water treatment costs, increased white water reuse rates, and reduced energy requirements for drying in the paper industry. Furthermore, the paper product obtained by the method of the present invention not only has good paper strength, paper quality, texture, etc., but also the method of the present invention allows paper to be produced with a constant quality.

Further, according to the paper manufacturing method of the present invention, the productivity of paper, the durability of the manufacturing machine, etc. can be improved, and the cost of producing paper can be reduced.

The numerous advantages of the present invention are that anionic colloidal silica particles having a unique elongated shape, having a substantially uniform thickness in the range of 5 to 20 millimeters and elongation only in one plane, can be immersed in a liquid. This is due to its ability to act on suspended fine charged particles and cause them to coagulate with strong cohesive force. Therefore, the elongated silica vines are useful not only for addition to papermaking stock solutions, but also for other technical fields that utilize the aggregation of finely suspended particles.

Applicant: Nissan Chemical Industries, Ltd.

Claims (2)

[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 has a substantially uniform thickness within the range of 5 to 20 millimeters. An elongated anionic silica sol that has elongation in one plane only and has a particle size of 40 to 300 millimicrons as measured by dynamic light scattering and a cationic group-containing polymer, and 1 part by weight of the above polymer. To this, the ratio of SiO_20.1 to 10 parts by weight of the silica sol, and the total amount of cellulose fiber or this and inorganic filler in the papermaking stock solution, the polymer is 0.0
A papermaking method characterized in that the addition is carried out at a ratio of 5 to 10.0% by weight. (2) The paper manufacturing method according to claim (1), wherein the amount of silica sol added is 0.05 to 5.0% by weight as SiO_2 based on the total amount of cellulose fibers or the inorganic filler in the papermaking stock solution. .