CN113201965A - Preparation method of paper stiffness agent, paper and preparation method thereof - Google Patents

Abstract

The application discloses a preparation method of a paper stiffness agent, paper and a preparation method thereof, wherein the preparation method of the paper stiffness agent comprises the following steps: obtaining a sodium silicate solution; adding a dilute acid solution into the sodium silicate solution to adjust the pH value of the sodium silicate solution; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution; and adding the cationic high molecular polymer into the first solution, and stirring to obtain the paper stiffness agent. The application utilizes the silicic acid that sodium silicate is replaced under the acid condition to form silicic acid sol to make silicic acid sol and cationic high molecular polymer react, so as to form paper stiffness agent, and the generated paper stiffness agent is added into paper pulp, so that the bonding strength of fibers can be improved, the toughness of fibers can be increased, and the stiffness of paper can be effectively improved.

Description

Preparation method of paper stiffness agent, paper and preparation method thereof

Technical Field

The application relates to the field of papermaking, in particular to a preparation method of a paper stiffness agent, paper and a preparation method of the paper stiffness agent.

Background

In recent years, with the continuous development of economy, the paper demand has been increasing year by year. Due to the shortage of raw materials, the pursuit of low cost by paper mills, and the environmental requirements of green production, the amount of secondary fibers used in paper is also increasing, resulting in poor paper strength.

Stiffness is an important strength index of paper strength, and the printing performance of paper is seriously affected by the stiffness variation, so that the printing efficiency is poor. In the prior art, physical methods are generally used to improve the paper stiffness.

However, the stiffness of the paper cannot be effectively improved only by a physical method, the quality and the use of the paper are seriously influenced, and the printing requirement and the use requirement of the paper cannot be met.

Disclosure of Invention

The technical problem mainly solved by the application is to provide a preparation method of a paper stiffness agent, paper and a preparation method of the paper stiffness agent, silicic acid replaced by sodium silicate under an acidic condition is utilized to form silicic acid sol, the silicic acid sol reacts with a cationic high molecular polymer to generate the paper stiffness agent, and the prepared paper stiffness agent is added in the subsequent paper making process, so that the problem that the paper stiffness cannot be effectively improved can be solved.

In order to solve the technical problems, a first technical scheme adopted by the application is to provide a preparation method of a paper stiffness agent, and the preparation method comprises the following steps: obtaining a sodium silicate solution; adding a dilute acid solution into the sodium silicate solution to adjust the pH value of the sodium silicate solution; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution; and adding the cationic high molecular polymer into the first solution, and stirring to obtain the paper stiffness agent.

Wherein the concentration of the obtained sodium silicate solution is 1-10%.

Wherein, dilute acid solution is added into the sodium silicate solution, and the step of adjusting the pH value of the sodium silicate solution specifically comprises the following steps: and adding a dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 3-7.

Wherein the dilute acid solution comprises dilute sulfuric acid and/or dilute hydrochloric acid.

Wherein the cationic high molecular polymer comprises polyaluminium chloride, and/or cationic polyacrylamide, and/or polyethyleneimine, and/or cationic starch.

Wherein the addition amount of the cationic high molecular polymer is 1-10% of the oven-dried sodium silicate salt in the first solution.

Wherein the stirring time is 30-60 min.

In order to solve the technical problems, the second technical scheme adopted by the invention is to provide a preparation method of paper, which comprises the following steps: preparing a paper stiffness agent by using the preparation method of the paper stiffness agent; preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding a paper stiffness agent with a set weight into the mixed paper pulp, uniformly stirring, and adding a filler and cationic starch to obtain the paper.

Wherein the set weight is 0.1-1% of the weight of the oven-dried pulp in the mixed paper pulp

In order to solve the technical problems, a third technical scheme adopted by the application is to provide paper, and the paper is prepared by the preparation method of the paper.

The beneficial effect of this application is: different from the prior art, the application provides a preparation method of a paper stiffness agent, paper and a preparation method thereof, silicic acid replaced by sodium silicate under an acidic condition is utilized to form silicic acid sol, and the silicic acid sol reacts with a cationic high molecular polymer to form the paper stiffness agent, the paper stiffness agent is a network-shaped cationic high molecular compound, and after the cationic high molecular compound is added into paper pulp and combined with fibers in the paper pulp, the combination strength of the fibers can be improved, the toughness of the fibers can be increased, and the stiffness of the paper can be effectively improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic flow diagram of one embodiment of a process for producing a paper stiffness agent according to the present application;

FIG. 2 is a schematic flow chart of an embodiment of a method of making a sheet of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plural" includes at least two in general, but does not exclude the presence of at least one.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that the terms "comprises," "comprising," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

In recent years, with the continuous development of economy, the paper demand has been increasing year by year. Due to the shortage of raw materials, the pursuit of low cost by paper mills, and the environmental requirements of green production, the amount of secondary fibers used in paper is also increasing, resulting in poor paper strength. Stiffness is an important strength index of paper strength, and the printing performance of paper is seriously affected by the stiffness variation, so that the printing efficiency is poor. In the prior art, physical methods are generally used to improve the paper stiffness. However, the stiffness of the paper cannot be effectively improved only by a physical method, the quality and the use of the paper are seriously influenced, and the printing requirement and the use requirement of the paper cannot be met.

Based on the situation, the application provides a preparation method of a paper stiffness agent, paper and a preparation method of the paper stiffness agent, silicic acid replaced by sodium silicate under an acidic condition is utilized to form silicic acid sol, the silicic acid sol reacts with a cationic high molecular polymer to generate the paper stiffness agent, and the prepared paper stiffness agent is added during subsequent paper making, so that the problem that the paper stiffness cannot be effectively improved can be solved.

The present application will be described in detail below with reference to the drawings and embodiments.

Referring to fig. 1, fig. 1 is a schematic flow chart of an embodiment of a method for preparing a paper stiffness agent according to the present application. As shown in fig. 1, in the present embodiment, the preparation method includes:

s11: obtaining the sodium silicate solution.

In the present embodiment, the concentration of the sodium silicate solution obtained is 1 to 10%.

Specifically, sodium silicate is divided into solid and liquid. The solid sodium silicate is colorless, white or off-white crystal flaky or agglomerated substance with molecular formula of Na₂SiO₃The corresponding molecular mass is 122. Liquid sodium silicate, also known as water glass, is usually nine molecules of bound water, with the molecular formula Na₂SiO₃·9H₂O, corresponding molecular mass 284.

If the sodium silicate used for preparing the sodium silicate solution with the set concentration is solid, calculating the mass of the required solid sodium silicate and the volume of the clear water or the pure water according to the set concentration, and weighing the solid sodium silicate with the corresponding mass to be dissolved in the clear water or the pure water with the corresponding volume to obtain the sodium silicate solution with the concentration of 1-10%.

If the sodium silicate used for preparing the sodium silicate solution with the set concentration is liquid, the concentration of the water glass is usually higher than 10%, and the water glass is diluted to obtain the sodium silicate solution with the concentration of 1-10%.

S12: and adding a dilute acid solution into the sodium silicate solution to adjust the pH value of the sodium silicate solution.

In the present embodiment, the sodium silicate solution is adjusted to a pH value (pH) of 3 to 7 using a dilute acid solution.

In a preferred embodiment, the pH of the sodium silicate solution is adjusted to 3-5 using a dilute acid solution.

Wherein the dilute acid solution comprises dilute sulfuric acid and/or dilute hydrochloric acid.

Specifically, since silicate ions are hydrolyzed to be alkaline, the sodium silicate solution is alkaline, and in order to form a silicate sol, the sodium silicate solution needs to be adjusted to be acidic, so that the silicate is replaced with silicic acid under acidic conditions (silicate ions react with hydrogen ions to form silicic acid), and the formed silicic acid is further reacted with hydrogen ions to form a silicate sol.

Because the dilute acid solution has little influence on the pH of the solution, the pH is adjusted by using the dilute acid solution, the pH of the sodium silicate solution cannot be instantly changed, and the pH of the sodium silicate solution can be gradually adjusted to a required pH value.

S13: and stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution.

In the present embodiment, the stirring time is 30 to 60 min.

Specifically, the sodium silicate solution after the addition of the dilute acid solution is stirred to complete the reaction, so that the silicic acid sol is preferably generated.

S14: and adding the cationic high molecular polymer into the first solution, and stirring to obtain the paper stiffness agent.

In this embodiment, the cationic high molecular polymer includes polyaluminum chloride, and/or cationic polyacrylamide, and/or polyethyleneimine, and/or cationic starch.

In this embodiment, the amount of the cationic polymer added is 1 to 10% of the oven-dried sodium silicate salt in the first solution.

When the sodium silicate used for preparing the sodium silicate solution with the set concentration is solid, the adding amount of the cationic high molecular polymer is 1-10% of the weight of the weighed sodium silicate solid; when the sodium silicate used for preparing the sodium silicate solution with the set concentration is liquid, calculating the mass of the sodium silicate in the water glass according to the concentration, wherein the adding amount of the cationic high molecular polymer is 1-10% of the mass of the sodium silicate in the water glass.

In a preferred embodiment, the cationic high molecular polymer is added in an amount of 1 to 2% of the oven-dried sodium silicate salt in the first solution.

In the present embodiment, the stirring time is 30 to 60 min.

Specifically, the silicate sol to which the cationic polymer is added is stirred to make the reaction between the polymer and the silicate sol more uniform, so as to form a cationic polymer compound having a network structure, i.e., a paper stiffness agent.

The paper stiffness agent is added into paper pulp, and after the cationic polymer compound is combined with fibers in the paper pulp in a reconstruction mode, the combination of adjacent fibers and fillers is promoted, so that the combination strength of the fibers can be improved, the toughness of the fibers can be improved, and the stiffness of the paper can be effectively improved.

Different from the prior art, the embodiment utilizes silicic acid replaced by sodium silicate under an acidic condition to form silicic acid sol, and the silicic acid sol reacts with the cationic high molecular polymer to form the paper stiffness agent, wherein the paper stiffness agent is a network-shaped cationic high molecular compound, and after the cationic high molecular compound is added into paper pulp and combined with fibers in the paper pulp, the combination strength of the fibers and the toughness of the fibers can be improved, so that the stiffness of the paper is effectively improved.

Correspondingly, the application provides a preparation method of the paper.

Specifically, please refer to fig. 2, fig. 2 is a schematic flow chart of an embodiment of a method for preparing a paper sheet according to the present application. As shown in fig. 2, in the present embodiment, the preparation method includes:

s21: the paper stiffness agent is prepared by the preparation method of the paper stiffness agent.

S22: preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp.

In the present embodiment, 20 parts by weight of bleached sulfate softwood pulp, 60 parts by weight of bleached sulfate hardwood pulp, 10 parts by weight of alkaline peroxide mechanical pulp, and 10 parts by weight of recycled broke pulp all refer to oven dry pulp.

S23: carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp.

S24: adding a paper stiffness agent with a set weight into the mixed paper pulp, uniformly stirring, and adding a filler and cationic starch to obtain the paper.

In the present embodiment, the amount of the binder is set to 0.1 to 1% by weight of the oven-dried slurry in the mixed pulp.

In a preferred embodiment, the setting amount is 0.3 to 0.5% by weight of the oven dried pulp in the mixed pulp.

In this embodiment, the filler added comprises ground calcium carbonate.

Wherein the adding amount of the filler is 15-25% of the weight of the oven-dried pulp in the mixed paper pulp.

Wherein the adding amount of the cationic starch is 0.8-1.2% of the weight of the oven-dried pulp in the mixed paper pulp.

The paper stiffness agent with the set weight is added into the paper pulp, and the cationic polymer compound is combined with the fiber in the paper pulp in a reconstruction mode, so that the combination of adjacent fibers and fillers is promoted, the strength of the fibers can be improved, the toughness of the fibers can be improved, and the stiffness of the paper can be effectively improved.

Different from the prior art, the paper stiffness agent prepared by adding the paper stiffness agent into the paper pulp is combined with the reconstruction of the paper stiffness agent and the paper pulp fibers, so that the combination strength of the fibers can be improved, the toughness of the fibers can be increased, and the stiffness of the paper can be effectively improved.

Correspondingly, the application also provides paper which is prepared by the preparation method of the paper.

Different from the prior art, including paper stiffness agent in the paper of this application, paper stiffness agent can promote the combination of adjacent fibre and filler to improve fibrous bonding strength and increase fibrous toughness, thereby make the stiffness of paper improve.

The following non-limiting examples are provided to facilitate an understanding of the embodiments of the present application and are set forth in the detailed description to provide further explanation of the embodiments of the present application.

Example 1

Obtaining a sodium silicate solution, wherein the concentration of the sodium silicate solution is 1%; adding a dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 3; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution, wherein the stirring time is 60 min; adding polyaluminium chloride into the first solution, and stirring to obtain a paper stiffness agent A, wherein the adding amount of the polyaluminium chloride is 1% of the absolute dry sodium silicate salt in the first solution, and the stirring time is 60 min; preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp, wherein the raw materials are all absolute dry pulp; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding a paper stiffness agent A with a set weight into the mixed paper pulp, uniformly stirring, adding heavy calcium carbonate and cationic starch, and making paper to obtain 60g/m²The amount of the cationic starch is 1 wt% of the oven-dried pulp in the mixed pulp, and the amount of the heavy calcium carbonate added is 20 wt% of the oven-dried pulp in the mixed pulp％。

Example 2

Obtaining a sodium silicate solution, wherein the concentration of the sodium silicate solution is 2%; adding a dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 4; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution, wherein the stirring time is 40 min; adding polyaluminium chloride into the first solution, and stirring to obtain a paper stiffness agent B, wherein the adding amount of the polyaluminium chloride is 2% of the absolute dry sodium silicate salt in the first solution, and the stirring time is 40 min; preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp, wherein the raw materials are all absolute dry pulp; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding a paper stiffness agent B with a set weight into the mixed paper pulp, uniformly stirring, adding heavy calcium carbonate and cationic starch, and making paper to obtain 60g/m²The amount of the heavy calcium carbonate added is 0.4% of the weight of the oven-dried pulp in the mixed pulp, and the amount of the cationic starch added is 1% of the weight of the oven-dried pulp in the mixed pulp.

Example 3

Obtaining a sodium silicate solution, wherein the concentration of the sodium silicate solution is 10%; adding a dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 5; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution, wherein the stirring time is 30 min; adding polyaluminium chloride into the first solution, and stirring to obtain a paper stiffness agent C, wherein the adding amount of the polyaluminium chloride is 10% of the absolute dry sodium silicate salt in the first solution, and the stirring time is 30 min; preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxideMechanical pulp; 10 parts by weight of recycled broke pulp, wherein the raw materials are all absolute dry pulp; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding paper stiffness agent C with set weight into the mixed paper pulp, uniformly stirring, adding heavy calcium carbonate and cationic starch, and making paper to obtain 60g/m²The amount of the added heavy calcium carbonate is 1% of the weight of the oven dry pulp in the mixed pulp, and the amount of the added cationic starch is 1% of the weight of the oven dry pulp in the mixed pulp.

Example 4

Obtaining a sodium silicate solution, wherein the concentration of the sodium silicate solution is 1%; adding a dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 3; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution, wherein the stirring time is 60 min; adding cationic polyacrylamide into the first solution and stirring to obtain a paper stiffness agent D, wherein the adding amount of the cationic polyacrylamide is 1% of the absolute dry sodium silicate salt in the first solution, and the stirring time is 60 min; preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp, wherein the raw materials are all absolute dry pulp; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding paper stiffness agent D with set weight into the mixed paper pulp, uniformly stirring, adding heavy calcium carbonate and cationic starch, and making paper to obtain 60g/m²The amount of the heavy calcium carbonate added is 0.1% of the weight of the oven-dried pulp in the mixed pulp, and the amount of the cationic starch added is 1% of the weight of the oven-dried pulp in the mixed pulp.

Example 5

Obtaining a sodium silicate solution, wherein the concentration of the sodium silicate solution is 2%; adding a dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 4; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution, wherein the stirring time is 40 min; adding cationic polyacrylamide into the first solution and stirring to obtain a paper stiffness agent E, wherein the adding amount of the cationic polyacrylamide is 2% of the oven-dried sodium silicate salt in the first solution, and the stirring time is 40 min; preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp, wherein the raw materials are all absolute dry pulp; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding a paper stiffness agent E with a set weight into the mixed paper pulp, uniformly stirring, adding heavy calcium carbonate and cationic starch, and making paper to obtain 60g/m²The amount of the added heavy calcium carbonate is 0.4% of the weight of the oven-dried pulp in the mixed pulp, and the amount of the added cationic starch is 1% of the weight of the oven-dried pulp in the mixed pulp.

Example 6

Obtaining a sodium silicate solution, wherein the concentration of the sodium silicate solution is 10%; adding a dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 5; stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution, wherein the stirring time is 30 min; adding cationic polyacrylamide into the first solution and stirring to obtain a paper stiffness agent F, wherein the adding amount of the cationic polyacrylamide is 10% of the absolute dry sodium silicate salt in the first solution, and the stirring time is 30 min; preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp, whereinThe raw materials are absolute dry slurry; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding a paper stiffness agent F with a set weight into the mixed paper pulp, uniformly stirring, adding heavy calcium carbonate and cationic starch, and making paper to obtain 60g/m²The amount of the added heavy calcium carbonate is 1% of the weight of the oven dry pulp in the mixed pulp, and the amount of the added cationic starch is 1% of the weight of the oven dry pulp in the mixed pulp.

Blank control group

Preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp, wherein the raw materials are all absolute dry pulp; carrying out pulp dispersing on bleached sulfate softwood pulp, bleached sulfate hardwood pulp, alkaline peroxide mechanical pulp and recycled broke pulp according to the raw material proportion to obtain mixed pulp; adding heavy calcium carbonate and cationic starch into the mixed paper pulp, and making into paper with a pulp to obtain 60g/m²The amount of the heavy calcium carbonate added is 20% of the weight of the oven dry pulp in the mixed pulp, and the amount of the cationic starch added is 1% of the weight of the oven dry pulp in the mixed pulp.

For examples 1, 2, 3, 4, 5, and 6 and the blank control group, the addition amount of the cationic polymer in the paper stiffness agent and the addition amount of the paper stiffness agent in the mixed pulp were recorded, and the stiffness of the paper was measured, and the test results are shown in table 1:

TABLE 1

As can be seen from the above table, the stiffness of the paper sheets obtained by paper making is increased to some extent by adding the paper stiffness agent to the mixed pulp in examples 1, 2, 3, 4, 5 and 6, compared with the blank control group; the greater the amount of cationic polymer added to the paper stiffness agent, and the greater the amount of paper stiffness agent added to the mixed pulp, the greater the stiffness of the paper.

Further, when the addition amount of the cationic polymer in the paper stiffness agent is 2% and the addition amount of the paper stiffness agent in the mixed pulp is 0.4%, the stiffness of the paper is greatly improved compared with that of the blank control group, and in view of the process cost, the addition amount of the cationic polymer in the paper stiffness agent can be controlled to be 2% or less, and the addition amount of the paper stiffness agent in the mixed pulp can be controlled to be 0.5% or less.

Different from the prior art, the embodiment utilizes silicic acid replaced by sodium silicate under an acidic condition to form silicic acid sol, and the silicic acid sol reacts with the cationic high molecular polymer to form the paper stiffness agent, wherein the paper stiffness agent is a network-shaped cationic high molecular compound, and after the cationic high molecular compound is added into paper pulp and combined with fibers in the paper pulp, the combination strength of the fibers and the toughness of the fibers can be improved, so that the stiffness of the paper is effectively improved.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.

Claims (10)

1. A preparation method of a paper stiffness agent is characterized by comprising the following steps:

obtaining a sodium silicate solution;

adding a dilute acid solution into the sodium silicate solution to adjust the pH value of the sodium silicate solution;

stirring the sodium silicate solution added with the dilute acid solution to obtain a first solution;

and adding a cationic high molecular polymer into the first solution, and stirring to obtain the paper stiffness agent.

2. The method for producing a paper stiffness agent according to claim 1,

the concentration of the obtained sodium silicate solution is 1-10%.

3. The method for preparing the paper stiffness agent according to claim 1, wherein the step of adding a dilute acid solution to the sodium silicate solution to adjust the pH value of the sodium silicate solution specifically comprises the steps of:

and adding the dilute acid solution into the sodium silicate solution, and adjusting the pH value of the sodium silicate solution to 3-7.

4. The method for producing a paper stiffness agent according to claim 1,

the dilute acid solution comprises dilute sulfuric acid, and/or dilute hydrochloric acid.

5. The method for producing a paper stiffness agent according to claim 1,

the cationic high molecular polymer comprises polyaluminium chloride, and/or cationic polyacrylamide, and/or polyethyleneimine, and/or cationic starch.

6. The method for producing a paper stiffness agent according to any one of claims 1 or 5,

the addition amount of the cationic high molecular polymer is 1-10% of the oven-dried sodium silicate salt in the first solution.

7. The method for producing a paper stiffness agent according to claim 1,

the stirring time is 30-60 min.

8. A method of making paper, comprising:

preparing a paper stiffness agent using the process of claims 1-7;

preparing the following raw materials in one hundred parts by weight: 20 parts by weight of bleached sulfate softwood pulp; 60 parts by weight of bleached sulfate hardwood pulp; 10 parts by weight of an alkaline peroxide mechanical pulp; 10 parts by weight of recycled broke pulp;

dispersing the bleached sulfate softwood pulp, the bleached sulfate hardwood pulp, the alkaline peroxide mechanical pulp and the recycled broke pulp according to a raw material ratio to obtain mixed pulp;

and adding a set amount of the paper stiffness agent into the mixed paper pulp, uniformly stirring, and adding a filler and cationic starch to obtain the paper.

9. The method for producing paper according to claim 8,

the set component is 0.1-1% of the weight of the oven-dried pulp in the mixed paper pulp.

10. Paper, characterized in that it is made by the process for the preparation of paper according to any one of claims 8 to 9.

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