WO2021120176A1

WO2021120176A1 - Manufacturing method for high-strength white kraft paper

Info

Publication number: WO2021120176A1
Application number: PCT/CN2019/127029
Authority: WO
Inventors: 陈传勇; 施彩莲; 陈奥; 陈欢欢; 吴飞燕; 童含信; 张维海
Original assignee: 浙江金龙纸业有限公司
Priority date: 2019-12-17
Filing date: 2019-12-20
Publication date: 2021-06-24
Also published as: CN110965391B; CN110965391A

Abstract

A coating composition for producing white kraft paper, a preparation method for the coating composition, and white kraft paper prepared using the coating composition. The coating composition is composed of the following components: 40-120 parts of calcium carbonate, 5-30 parts of kaolin, 0.8-1.2 parts of sodium polyacrylate, 7.8-13 parts of anionic styrene-butadiene latex, 1-8 parts of oxidized konjac glucomannan, 0.1-1.5 parts of citrus pectin, 1-4 parts of silicon dioxide nano-modified soybean protein, 0.1-0.7 part of carboxymethylcellulose, 0.15-0.3 part of polyethylene glycol, 0.2-0.5 part of glyoxal, 0.1-0.3 part of an organic silicon defoaming agent, 0.03-0.05 part of sodium hydroxide, and 50-80 parts of water. According to the coating composition, industrial synthetic latex is substantially replaced with a bio-natural adhesive, thereby solving the problems that the industrial synthetic latex is difficult to degrade, causes environmental pollution, etc.; in addition, the printing performance of white board paper can be effectively improved by adding modified konjac polysaccharide, citrus pectin and nano-modified soybean protein.

Description

Method for manufacturing high-strength white-faced cow cardboard

Technical field

The present invention relates to the technical field of pulping and papermaking production, in particular to a method for manufacturing high-strength white-faced cattle cardboard. Specifically, the present invention uses a coating composition and a gray-bottomed whiteboard wood chip pulp to prepare white-faced cattle cardboard, and particularly relates to coating Cloth white paper, gray-bottom white paper or white paper.

Background technique

Coated whiteboard paper generally includes a surface layer, a lining layer, a core layer and a bottom layer. The first layer is a surface layer pulp, which requires high whiteness and certain strength. Usually, bleached kraft wood pulp or partially bleached chemical straw pulp is used. And white paper edge waste paper pulp; the second layer is the lining layer, which also requires a certain degree of whiteness, usually 100% mechanical wood pulp or light-colored waste paper pulp; the third layer is the core layer, which is mainly used for filling to increase the cardboard Thickness, generally used mixed waste paper pulp or straw pulp, the last layer is the bottom layer, which can improve the appearance of the cardboard and increase the strength. It is usually made with high-yield pulp or better waste paper pulp as raw materials. The color of the bottom of the cardboard is gray.

Generally speaking, the surface layer of the coated whiteboard will be covered with a layer of paint with good ink absorption, in order to obtain a paper surface with good uniformity and smoothness. The paper coating process is to fill and cover the uneven surface formed by criss-crossing and crisscrossing the fibers of the coated base paper with the pigment in the coating. The pigment in the coating has appropriate whiteness and particle size, which can improve the whiteness, smoothness and gloss of the coated paper, while giving it good ink absorption. At present, as the main component pigments of paint, there are three types of natural mineral pigments, artificial pigments and synthetic pigments. The natural mineral raw materials are mainly calcium carbonate, china clay, and kaolin; artificial pigments are mainly aluminum hydroxide, wrought white, titanium white, and silicon. Acid aluminum; synthetic pigments are mainly polystyrene resin and urea resin, of which calcium carbonate is the most widely used as paint pigment and the largest amount. The type and performance of the pigment determine the performance and quality of the coated base paper.

Coating adhesive, as a coating component second only to pigment, directly affects the quality of coatings and coated paper. Coating adhesives can be divided into two categories according to their sources: natural adhesives such as animal glue, starch and casein, and synthetic adhesives such as styrene-acrylic latex, styrene-butadiene latex and polyvinyl alcohol. Compared with natural adhesives, synthetic latex adhesives have better elasticity and plasticity. The coated paper produced by using it as a coating adhesive can easily produce higher gloss and high smoothness of the paper surface after calendering. , Good flexibility, strong water resistance, good paper dimensional stability. At present, in the prior art, synthetic latex adhesives are mostly used in coating whiteboard paper.

However, due to the improvement of people's living standards and environmental protection awareness, the composition of cardboard adhesives has attracted more and more attention. Adhesives artificially synthesized by petroleum have the problems of toxic volatilization, refractory degradation and non-renewability. Renewable and environmentally friendly adhesives have become increasingly popular substances. In order to solve the various deficiencies in the use of natural adhesives, the prior art usually adopts the method of adding auxiliary adhesives to solve them, for example, by adding soy protein polymer to improve the rheological properties and solid content of the coating. , The single addition of soybean protein polymer can improve the performance of the coating only and cannot fully meet the requirements of industrial production. The whiteness, smoothness, ink absorption and other properties of the coated white paper produced need to be further improved.

It can be seen that obtaining a coating composition with good performance for producing coated white paper, and then producing high-quality, low-cost coated white paper, is an urgent problem in this field.

Summary of the invention

In order to solve the problems of the prior art, the present invention provides a coating composition for producing white-faced cow cardboard and a preparation method thereof. The coating composition is modified by adding modified konjac polysaccharide, citrus pectin and nano-modified Soy protein improves the performance of the coating, and the coated white paper produced from it has good whiteness and printing performance.

In one embodiment, the present invention provides a coating composition for the production of white-faced cow cardboard, characterized in that the coating composition consists of the following components: 40-120 parts of calcium carbonate and 5-30 parts of kaolin , 0.8-1.2 parts of dispersant, 7.8-13 parts of latex, 1-8 parts of oxidized konjac glucomannan, 0.1-1.5 parts of citrus pectin, 1-4 parts of nano-modified soy protein, rheology modifier 0.1- 0.7 part, lubricant 0.15-0.3 part, water repellent 0.2-0.5 part, defoaming agent 0.1-0.3, sodium hydroxide 0.03-0.05 part, water 50-80 part.

In one embodiment, the coating composition is composed of a pre-coated coating and a top coating. The pre-coated coating components are 83 parts of calcium carbonate, 21 parts of kaolin, 1.1 parts of sodium polyacrylate, and 6.5 parts of anionic styrene butadiene latex. 1-8 parts of oxidized konjac glucomannan, 0.1-1.5 parts of citrus pectin, 1-4 parts of silicon dioxide nano-modified soy protein, 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, ethylene two 0.3 parts of aldehyde, 1.5 parts of silicone defoamer, 0.03 parts of sodium hydroxide, 75 parts of water;

In one embodiment, the ingredients of the top coat paint are 68 parts of calcium carbonate, 43 parts of kaolin, 1 part of sodium polyacrylate, 5.5 parts of anionic styrene butadiene latex, 1-8 parts of oxidized konjac glucomannan, and citrus pectin. 0.1-1.5 parts, 1-4 parts of nano-modified soy protein, 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, 0.3 parts of glyoxal, 1.5 parts of silicone defoamer, 0.03 parts of sodium hydroxide , 70 parts of water.

In one embodiment, the silica nano soy protein in the pre-coating paint is 2.6 parts, the oxidized konjac glucomannan is 7.5 parts, and the addition amount of citrus pectin is 1 part.

In one embodiment, the silica nano soy protein in the top coating is 3.4 parts; the oxidized konjac glucomannan is 5.5 parts, and the citrus pectin is 1.2 parts.

In one embodiment, soy protein is widely used in the papermaking industry as an adhesive for the preparation of coating whiteboards. For example, soy protein polymer Pro-Cote4610 is used as an additive to prepare whiteboard coatings, usually In order to further improve the performance of soy protein as a coating additive, the art will adopt modified methods for soy protein, such as nano-modification. Compared with the original soy protein, the adhesive properties of silica nano-soy protein will be improved. Is further improved. The preparation method of the silica nano-soy protein adopts conventional methods in the field, for example, refer to the method described in "Study on the Effect of Nanomaterials on Soy Protein Bioadhesive, Zhang Xuejun, Master's Thesis of Jiangnan University, 2008", And make corresponding adjustments, the specific steps are:

Disperse the soy protein isolate in water, stir for 30 minutes, and then maintain a certain temperature, add 1.2% nano-silica, stir at 10000 rpm for 2 minutes, and ultrasonically treat for 0.5 h to obtain a silica nano-modified soy protein.

In one embodiment, the konjac glucomannan is a kind of konjac polysaccharide, which has some characteristics, such as poor sol stability and poor fluidity. In order to improve the performance of konjac glucomannan, it is usually Glucomannan is modified, such as deacetylation, crosslinking, esterification, oxidation, graft copolymerization, etc. The modified konjac glucomannan is mostly used to prepare wood glue. In the present invention, konjac glucomannan is oxidatively modified, and the modification method can refer to the methods known in the prior art, for example, refer to "Research on Konjac Polysaccharide Wood Adhesive, Mao Jie, Fujian Agriculture and Forestry University , Master's thesis, 2009" and make corresponding adjustments to the modification methods, the specific steps are:

Add konjac refined distilled water into the flask, stir at room temperature for a period of time with a motor, and let it swell into a paste; take 1mol/L NaOH solution and 30% H ₂ O ₂ solution and add the swollen konjac powder paste In a three-necked flask, placed in a water bath at 50℃ and reacted with stirring for 30min, add an appropriate amount of anhydrous sodium sulfite solution to stop the oxidation reaction, then slowly add the remaining NaOH solution for gelatinization for 10min, then add dilute hydrochloric acid and dilute Sodium hydroxide adjusts the pH to 6.5, cools and discharges.

In one embodiment, the preparation method of the citrus pectin can be any method known in the art for preparing citrus pectin, for example, take the citrus peel, boil it in water for 5 minutes, add a 1:1 hydrochloric acid solution and water reflux For half an hour, filter to remove solids to obtain citrus pectin solution.

In one embodiment, the present invention provides a preparation method of a coating composition for producing white-faced cow cardboard, and the preparation steps are as follows:

Mix a portion of kaolin, calcium carbonate and sodium polyacrylate, stir at a speed of 1600r/min for 8min, after stirring, the stirring speed will be reduced to 1000r/min, and then add oxidized konjac glucomannan citrus pectin, anionic styrene butadiene latex, For nano-modified soy protein, stir for 10 minutes after each component is added, and finally add carboxymethyl cellulose, polyethylene glycol, glyoxal, silicone defoamer, sodium hydroxide, and each component Stir for 4 minutes after dividing to prepare the coating.

In one embodiment, the present invention provides a use of a coating composition for producing white-faced cow cardboard in the preparation of coated white paper

In one embodiment, the present invention provides a coated whiteboard paper prepared from a coating composition for producing white-faced cow cardboard.

In other embodiments, the present invention also provides a method for preparing high-grade coated whiteboard paper using the coating composition and gray-bottomed whiteboard wood chip pulp; the gray-bottomed whiteboard wood chip pulp includes ONP pulp, DIP pulp and OCC pulp.

Compared with the prior art, the present invention has the following advantages: the coating composition for producing coated white paper of the present invention uses biological natural adhesive to largely replace the industrially synthesized latex, and solves the problem that the industrially synthesized latex is difficult to degrade. Environmental pollution. At the same time, the addition of modified konjac polysaccharide, citrus pectin and nano-modified soybean protein can effectively improve the printing performance of white paper. Through exploration, the optimal addition amount has been determined, and it has a good market expectation.

Detailed ways

Hereinafter, the effect of the coating composition for coating white paper of the present invention will be described in detail through the best embodiment of the present invention. However, the following content should not be construed as limiting the scope of protection of the present invention.

Example 1 A manufacturing method of high-strength white-faced cattle cardboard

This embodiment provides a method for preparing a coating composition for coating white paper with excellent performance by adding modified konjac polysaccharide, citrus pectin, and nano-modified soybean protein.

Specific steps are as follows:

1. Preparation of oxidized konjac glucomannan:

(1) Put 45 g of refined konjac powder and 3 L of distilled water into the flask, stir with a motor for a period of time at room temperature and then let it stand to swell into a paste.

(2) Take 10ml of 1 mol/L NaOH solution and 10ml of 30% H ₂ O ₂ solution into a three-necked bottle of swollen konjac flour paste, place it in a water bath at 50°C and stir for 30 min. , Add an appropriate amount of anhydrous sodium sulfite solution to stop the oxidation reaction, then slowly add the remaining 20ml of NaOH solution for gelatinization for 10 minutes, add dilute hydrochloric acid and dilute sodium hydroxide to adjust the pH to 6.5 after a period of time, cool and discharge, and set aside .

2. Preparation of citrus pectin:

Take 100 grams of citrus peel, boil it in water for 5 minutes, add 50ml 1:1 hydrochloric acid solution and 400ml of water to reflux for half an hour, filter to remove solids, and obtain citrus pectin solution for use.

3. Preparation of soy protein modified by silica nanometer:

Disperse 100 g of soy protein isolate in 1 L of water, stir for 30 minutes, and then maintain a certain temperature, add 1.2% nano-silica, stir at 10000 rpm for 2 minutes, and ultrasonically treat for 0.5 h to prepare nano-modified soy protein.

4. Preparation of pre-coated paint:

Mix 68 parts of kaolin, 21 parts of calcium carbonate and 1 part of sodium polyacrylate, stir for 8 minutes at a speed of 1600r/min. After the stirring is even, the stirring speed is reduced to 1000r/min, and then 1-8 parts of oxidized konjac glucomannan are added in sequence. Sugar, 0.1-1.5 parts of citrus pectin, 4.5 parts of anionic styrene-butadiene latex, 1-4 parts of nano-modified soy protein, after adding each component, stir for 10 minutes, and finally add 0.48 parts of carboxymethyl cellulose, poly 0.22 parts of ethylene glycol, 0.3 parts of glyoxal, 1.5 parts of organosilicon defoamer, 0.03 parts of sodium hydroxide, each component is added and stirred for 4 minutes to prepare a pre-coated paint.

5. Preparation of top coating:

Mix 83 parts of kaolin and 43 parts of calcium carbonate with 1.1 parts of sodium polyacrylate, stir at a speed of 1600r/min for 8min, after stirring, the stirring speed will be reduced to 1000r/min, and then add 1-8 parts of oxidized konjac glucomannan Sugar, 0.1-1.5 parts of citrus pectin, 4.5 parts of anionic styrene-butadiene latex, 1-4 parts of nano-modified soy protein, after adding each component, stir for 10 minutes, and finally add 0.48 parts of carboxymethyl cellulose, poly 0.22 parts of ethylene glycol, 0.3 parts of glyoxal, 1.5 parts of organosilicon defoamer, 0.03 parts of sodium hydroxide, each component is added and stirred for 4 minutes to prepare a top coating.

Example 2 Method for preparing coated white paper using the coating composition prepared in Example 1

This embodiment provides the use of the coating composition obtained in Example 1 to prepare coated white paper to obtain high-grade coated white paper with excellent printing performance. The specific steps are as follows:

1. Preparation of various slurries:

(1) Preparation of ONP pulp: Take Japan 3# and Mei Waste 8# as raw materials, and the weight ratio of Japan 3# and Mei Waste 8# is 3:7. After crushing, screening, slag removal, deinking, and concentration, OCC slurry is obtained by thermal dispersion; the ONP deinking slurry has a freeness of 210 csf, a brightness value of 40 ISO, and a content of impurity points of 980 mm ² /m ² ;

(2) Preparation of DIP pulp: Using Mei Waste 3# and Mei Waste 8# as raw materials, the weight ratio of Mei Waste 3# and Mei Waste 8# is 1:1, after crushing, screening, slag removal, deinking, Concentrate and thermally disperse to obtain OCC slurry for use. The freeness of the DIP slurry is 230csf, the brightness value is 55ISO, and the impurity point content is 800mm ² /m ²

(3) Preparation of OCC pulp: using domestic waste corrugated paper as a raw material, OCC pulp is obtained through crushing, screening, deslagging, concentration, and thermal dispersion; the beating degree of the OCC pulp is 48.5°SR.

2. Different levels of slurry preparation

Surface layer slurry preparation: the ONP slurry and DIP slurry prepared by the above steps are the surface layer slurry, wherein the ratio of ONP slurry and DIP slurry is 2:1, and the slurry weight is 32.9g/m ² ;

Preparation of lining slurry: use the ONP slurry and OCC slurry prepared in the above steps as lining slurry, wherein the ratio of ONP slurry to OCC slurry is 1:1, and the slurry weight is 21.2g/m ² ;

Preparation of core layer slurry: the OCC slurry prepared in the above steps is used as the core layer slurry, and the core layer slurry has a basis weight of 96g/m ² ;

Bottom slurry preparation and slurry preparation: the ONP slurry and OCC slurry prepared in the above steps are used as lining slurry, wherein the ratio of ONP slurry and OCC slurry is 1:3, and the slurry weight is 31.6g/m ² ;

3. Copymaking of base paper:

Each layer of slurry is conveyed to the headbox of the paper machine through its own feeding system, and the above-mentioned layers of slurry of a certain concentration are applied to the four-layer forming net to form a wet paper sheet. After pressing, the front drying section, and the surface sizing , Hard calendering to make raw paper;

4. Coating

The coated base paper after hard calendering is sent to a curtain coater, and on the front sizing layer of the coated base paper, the pre-coating paint prepared in Example 1 is used for curtain coating to form a pre-coating layer , And then send the coating base paper forming the curtain coating to the knife coater, and use the topcoat paint prepared in Example 1 to knife coat to form the topcoat, wherein the coating amount of the precoat is 8g/m ^2. The coating amount of the top coat is 11g/m ² .

5. Soft calendering and coiling:

After coating, it will be soft calendered, coiled and recoiled into storage.

Example 3 Effect of the addition amount of different oxidized konjac glucomannan and citrus pectin on the properties of white paper

In order to explore the effect of different oxidized konjac glucomannan and citrus pectin on the properties of white paper, and strive to find the most suitable oxidized konjac glucomannan and citrus pectin, the following experimental design is used in this example :

In the preparation of top coating and pre-coating coatings, different amounts of oxidized konjac glucomannan and citrus pectin are used for treatment, and the addition of silica nano-modified soybeans to top coatings and pre-coating coatings is eliminated. Protein steps to analyze and determine the most appropriate amount of oxidized konjac glucomannan and citrus pectin. The specific amounts are shown in Table 1.

Table 1 Addition of oxidized konjac glucomannan and citrus pectin

For the above different concentrations, 3 parallel experiments are set up in each group. The specific steps are as follows

1. Preparation of oxidized konjac glucomannan:

(2) Take 10ml of 1mol/L NaOH solution and 10ml of 30% H ₂ O ₂ solution into a three-necked flask of swollen konjac flour paste, and place it in a water bath at 50°C for 30 minutes with stirring. Add an appropriate amount of freshly prepared anhydrous sodium sulfite solution to terminate the oxidation reaction, then slowly add the remaining 20ml of NaOH solution for gelatinization for 10 minutes, add dilute hydrochloric acid and dilute sodium hydroxide to adjust pH 6.5 after a period of time, cool and discharge, and set aside.

2. Preparation of citrus pectin:

3. Preparation of pre-coated paint:

Mix 68 parts of kaolin, 21 parts of calcium carbonate and 1 part of sodium polyacrylate, and stir for 8 minutes at a speed of 1600r/min. After stirring, the stirring speed is reduced to 1000r/min, and then add oxidized konjac glucomannan and citrus fruit in sequence. Gum, 4.5 parts of anionic styrene-butadiene latex, stir for 10 minutes after each component is added, and finally add 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, 0.3 parts of glyoxal, 1.5 parts of silicone defoamer , 0.03 parts of sodium hydroxide, each component is added and stirred for 4 minutes to prepare a pre-coated paint. Among them, the addition amounts of oxidized konjac glucomannan and citrus pectin are shown in Table 1. The control group does not contain oxidized konjac Glucomannan, citrus pectin, anionic styrene-butadiene latex add 9.5 parts.

4. Preparation of top coating:

Mix 83 parts of kaolin, 43 parts of calcium carbonate and 1.1 parts of sodium polyacrylate, stir at 1600r/min for 8min, after stirring uniformly, the stirring speed will be reduced to 1000r/min, and then add oxidized konjac glucomannan and part of citrus. Pectin, 4.5 parts of anionic styrene-butadiene latex, stir for 10 minutes after each component is added, and finally add 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, 0.3 parts of glyoxal, and 1.5 parts of silicone defoamer. Sodium hydroxide 0.03 parts, each component is added and stirred for 4 minutes to prepare a top coating. Among them, the addition amount of oxidized konjac glucomannan and citrus pectin is shown in Table 1, and the control group does not contain oxidized konjac glucomannan and citrus pectin. Konjac glucomannan and citrus pectin, anionic styrene-butadiene latex add 9.5 parts.

5. Preparation of various slurries:

6. Preparation of different levels of slurry

7. Copying of base paper:

8. Coating

The hard calendered coated base paper is sent to a curtain coater, and on the front sizing layer of the coated base paper, the pre-coating paint prepared in step 3 is used for curtain coating to form a pre-coating layer, Then the coated base paper forming the curtain coating is sent to a knife coater, and the topcoat paint prepared in step 4 is used for knife coating to form a topcoat, wherein the coating amount of the precoat is 8g/m ² , The coating amount of the top coat is 11 g/m ² .

9. Soft calendering and coiling:

After coating, it will be soft calendered, coiled and recoiled into storage.

10. Whiteboard paper test results

The performance of the whiteboard paper 1-whiteboard paper 9 prepared by the above method and the control group were tested. The specific testing indicators were whiteness, gloss, PPS roughness, ink absorption, and printing surface strength, among which,

The whiteness of coated white paper shall be tested in accordance with GB/T 7974-2004;

The gloss of coated white paper shall be tested according to GB/T8941.3-1988;

The PPS roughness of the coated white paper is tested according to GB/T 2679.9-1993;

The ink absorbency of coated white paper shall be tested in accordance with GB/T12911-991);

The printing surface strength of coated white paper shall be tested in accordance with GB/T10341-1989;

The effects of different oxidized konjac glucomannan and citrus pectin on the properties of white paper are shown in Table 2.

Table 2 Performance of Whiteboard Paper 1-Whiteboard Paper 9

From the results shown in Table 2, it can be seen that the addition of oxidized konjac glucomannan and citrus pectin has improved various parameters related to printing and surface performance compared with the control group. This shows that the oxidized konjac glucomannan and citrus pectin have improved Sugar and citrus pectin help to improve the printing and surface properties of the white paper prepared by them. Furthermore, from the results in Table 2, it can be concluded that the addition amount of oxidized konjac glucomannan in the precoat paint is 7.5 parts, the addition amount of citrus pectin is 1 part, and the addition amount of oxidized konjac glucomannan in the topcoat paint is 5.5 parts and 1.2 parts of citrus pectin (ie white board 6), the prepared white paper has the best printing and surface properties.

Example 4 Effect of the addition amount of silica nano-modified soy protein on the properties of white board paper

In order to explore the influence of the addition amount of different silica nano-modified soybean protein on the performance of whiteboard paper, and strive to find the most suitable addition amount of silica nano-modified soybean protein, this example adopts the following experimental design:

In the preparation of top coating and pre-coating coatings, different addition amounts of silica nano-modified soy protein are used for processing, and the addition of oxidized konjac glucomannan and citrus pectin to top coatings and pre-coating coatings is eliminated. To analyze and determine the most suitable silica nano-modified soy protein, the specific addition amount is shown in Table 1.

Table 3 Addition amount of silica nano-modified soy protein

1. Preparation of soy protein modified by silica nanometer:

2. Preparation of pre-coated paint:

Mix 68 parts of kaolin, 21 parts of calcium carbonate and 1 part of sodium polyacrylate, and stir for 8 minutes at a speed of 1600r/min. After the stirring is uniform, the stirring speed is reduced to 1000r/min, and then the silica nano-modified soybean protein is added in sequence , 4.5 parts of anionic styrene-butadiene latex, stir for 10 minutes after each component is added, and finally add 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, 0.3 parts of glyoxal, 1.5 parts of silicone defoamer, Sodium hydroxide 0.03 parts, each component is added and stirred for 4 minutes to prepare a pre-coated paint. Among them, the addition amount of silica nano-modified soy protein is shown in Table 3, and the control group does not contain silica nano-modified For the soybean protein, the addition amount of anionic styrene-butadiene latex is 9.5 parts (same as the control group in Example 3, the adhesive is only anionic styrene-butadiene latex).

3. Preparation of top coating:

Mix 83 parts of kaolin, 43 parts of calcium carbonate and 1.1 parts of sodium polyacrylate, stir at 1600r/min for 8min, after stirring uniformly, the stirring speed will be reduced to 1000r/min, and then add oxidized konjac glucomannan and part of citrus. Pectin, 4.5 parts of anionic styrene-butadiene latex, stir for 10 minutes after each component is added, and finally add 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, 0.3 parts of glyoxal, and 1.5 parts of silicone defoamer. Sodium hydroxide 0.03 parts, each component is added and stirred for 4 minutes to prepare a top coat paint. The addition amount of silica nano-modified soy protein is shown in Table 3. The control group does not contain silica For the nano-modified soybean protein, the addition amount of anionic styrene-butadiene latex is 9.5 parts (same as the control group in Example 3, and the adhesive is only anionic styrene-butadiene latex).

4. Preparation of various slurries:

5. Preparation of different levels of slurry

6. Copying of base paper:

7. Coating

8. Soft calendering and coiling:

After coating, it will be soft calendered, coiled and recoiled into storage.

9. Whiteboard paper test results

The performance of the whiteboard paper 10-whiteboard paper 13 prepared by the above method and the control group were tested. The specific testing indicators were whiteness, gloss, PPS roughness, ink absorption, and printing surface strength. Among them,

The gloss of coated white paper shall be tested according to GB/T8941.3-1988;

The influence of silica nano-modified soy protein on the properties of white paper is shown in Table 4.

Table 4 Performance of White Board Paper 10-White Board Paper 13

It can also be seen from the results in Table 4 that the addition of silica nano-modified soy protein is beneficial to improve the roughness of the cardboard PPS and increase the gloss of the cardboard, and the silica nano soy protein will promote the rapid curing of the coating and increase The coating structure with high pore volume improves the ink absorption of the coated paper. Furthermore, from the result of 4, it can be concluded that the addition amount of silica nano soy protein in the pre-coating paint is 2.6 parts, and the silica nano soy protein in the top coat paint is 3.4 parts (ie, white board paper 11). Whiteboard paper has the best printing and surface performance.

Example 5 The synergistic effect of adding silica nano soy protein, oxidized konjac glucomannan and citrus pectin at the same time on the properties of white paper

It can be seen from the above examples that the addition of silica nano soy protein, or oxidized konjac glucomannan and citrus pectin can improve the printing and surface properties of white paper to a certain extent. This example is an improvement. To explore whether the simultaneous addition of silica nano-soy protein, oxidized konjac glucomannan and citrus pectin can synergistically improve the physical properties of white paper. The experimental design is as follows:

The addition amount of silica nano soy protein, oxidized konjac glucomannan and citrus pectin determined in the above examples is selected, that is, the addition amount of silica nano soy protein in the pre-coating paint is 2.6 parts, and the addition amount of the silica nano soy protein in the top coat Silica nano soy protein is 3.4 parts; the addition amount of oxidized konjac glucomannan in the pre-coating paint is 7.5 parts, the addition amount of citrus pectin is 1 part, and the addition amount of oxidized konjac glucomannan in the top coating paint is 5.5 parts. The amount of citrus pectin added is 1.2 parts, and the corresponding coated white paper 14 is prepared. The specific steps are as follows:

1. Preparation of oxidized konjac glucomannan:

2. Preparation of citrus pectin:

Take 100 grams of citrus peel, boil it with water for 5 minutes, add 50ml 1:1 hydrochloric acid solution and 400ml of water to reflux for half an hour, filter to remove solids, and obtain citrus pectin solution for use.

3. Preparation of soy protein modified by silica nanometer:

4. Preparation of pre-coated paint:

Mix 68 parts of kaolin, 21 parts of calcium carbonate and 1 part of sodium polyacrylate, and stir for 8 minutes at a speed of 1600r/min. After stirring, the stirring speed is reduced to 1000r/min, and then add oxidized konjac glucomannan and citrus fruit in sequence. Gum, silica nano soy protein, 4.5 parts of anionic styrene-butadiene latex, stir for 10 minutes after each component is added, and finally add 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, and 0.3 parts of glyoxal. 1.5 parts of organosilicon defoaming agent, 0.03 parts of sodium hydroxide, each component is added and stirred for 4 minutes to prepare a pre-coated paint. Among them, the addition amount of silica nano-soy protein is 2.6 parts, and the konjac glucomannan is oxidized. The addition amount is 7.5 parts, and the addition amount of citrus pectin is 1 part.

5. Preparation of top coating:

Mix 83 parts of kaolin and 43 parts of calcium carbonate with 1.1 parts of sodium polyacrylate. Stir at a speed of 1600r/min for 8min. After stirring, the stirring speed is reduced to 1000r/min, and then add oxidized konjac glucomannan and part of citrus. Pectin, silica nano soy protein, 4.5 parts of anionic styrene-butadiene latex, stir for 10 minutes after each component is added, and finally add 0.48 parts of carboxymethyl cellulose, 0.22 parts of polyethylene glycol, and 0.3 parts of glyoxal , 1.5 parts of organosilicon defoaming agent, 0.03 parts of sodium hydroxide, each component is added and stirred for 4 minutes to obtain a top coat paint. Among them, the silicon dioxide nano soy protein in the top coat paint is 3.4 parts, and the top coat paint The added amount of mid-oxidized konjac glucomannan is 5.5 parts, and the added amount of citrus pectin is 1.2 parts.

6. Preparation of various slurries:

7. Preparation of different levels of slurry

8. Copymaking of base paper:

9. Coating

10. Soft calendering and coiling:

After coating, it will be soft calendered, coiled and recoiled into storage.

11. Whiteboard paper test results

The gloss of coated white paper shall be tested according to GB/T8941.3-1988;

The effect of adding silica nano soy protein, oxidized konjac glucomannan and citrus pectin to the properties of white paper is shown in Table 5.

Table 5 Performance of Whiteboard Paper 14

As shown in Table 5, the addition of silica nano soy protein, oxidized konjac glucomannan and citrus pectin at the same time improves the surface and factor performance of the white paper is significantly better than the single addition of silica nano soy protein or the single addition of oxidation Konjac glucomannan and citrus pectin, which produce a synergistic effect.

In the above, the present invention has been described in detail with general descriptions and specific embodiments, but on the basis of the present invention, some modifications or improvements can be made, which is obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of the present invention.

Claims

A coating composition for producing white-faced cow cardboard, characterized in that the coating composition is composed of the following components: 40-120 parts of calcium carbonate, 5-30 parts of kaolin, 0.8-1.2 parts of sodium polyacrylate, anionic 7.8-13 parts of styrene-butadiene latex, 1-8 parts of oxidized konjac glucomannan, 0.1-1.5 parts of citrus pectin, 1-4 parts of soy protein modified by silica nanometer, 0.1-0.7 parts of carboxymethyl cellulose , 0.15-0.3 parts of polyethylene glycol, 0.2-0.5 parts of glyoxal, 0.1-0.3 parts of organosilicon defoamer, 0.03-0.05 parts of sodium hydroxide, 50-80 parts of water.
The coating composition for producing white-faced cattle cardboard of claim 1, wherein the coating composition is composed of a pre-coated coating and a top-coating coating, and the pre-coating coating composition is 83 parts of calcium carbonate and kaolin. 21 parts, 1.1 parts of sodium polyacrylate, 6.5 parts of anionic styrene butadiene latex, 1-8 parts of oxidized konjac glucomannan, 0.1-1.5 parts of citrus pectin, 1-4 parts of silica nano-modified soy protein, carboxylate 0.48 parts of methyl cellulose, 0.22 parts of polyethylene glycol, 0.3 parts of glyoxal, 1.5 parts of silicone defoamer, 0.03 parts of sodium hydroxide, 75 parts of water; the composition of the top coating is 68 parts of calcium carbonate , 43 parts of kaolin, 1 part of sodium polyacrylate, 5.5 parts of anionic styrene-butadiene latex, 1-8 parts of oxidized konjac glucomannan, 0.1-1.5 parts of citrus pectin, 1-4 parts of nano-modified soy protein, carboxymethyl 0.48 parts of base cellulose, 0.22 parts of polyethylene glycol, 0.3 parts of glyoxal, 1.5 parts of silicone defoamer, 0.03 parts of sodium hydroxide, and 70 parts of water.
The coating composition for producing white-faced cow cardboard as claimed in claim 1-2, characterized in that the silica nano-soy protein in the pre-coated coating is 2.6 parts, and the oxidized konjac glucomannan is 7.5 parts, The amount of citrus pectin added is 1 part.
The coating composition for producing white-faced cow cardboard according to any one of claims 1 to 3, wherein the silica nano-soy protein in the top coating is 3.4 parts; the oxidized konjac glucomannan is 5.5 parts and 1.2 parts of citrus pectin.
The coating composition for producing white-faced cow cardboard according to any one of claims 1 to 4, wherein the preparation method of silica nano soy protein is to disperse the soy protein isolate in water, stir for 30 minutes, and then Maintaining a certain temperature, adding 1.2% nano-silica, stirring at 10000 rpm for 2 mins, and ultrasonic treatment for 0.5 h, to obtain a silica nano-modified soybean protein.
The coating composition for the production of white-faced cow cardboard according to any one of claims 1-5, wherein the preparation method of the oxidized konjac glucomannan is to add konjac refined powder and distilled water into a flask, and use it at room temperature. After the motor is stirred for a period of time, let it stand to swell into a paste; take 1mol/L NaOH solution and 30% H 2 O 2 solution into a three-necked bottle of swollen konjac powder paste, and place it in a water bath at 50°C Stir the reaction in the pot for 30 minutes, add an appropriate amount of anhydrous sodium sulfite solution to stop the oxidation reaction, then slowly add the remaining NaOH solution for gelatinization for 10 minutes, then add dilute hydrochloric acid and dilute sodium hydroxide to adjust the pH to 6.5, and cool the material.
The coating composition for producing white-faced cow cardboard according to any one of claims 1-6, the preparation method of the citrus pectin is to take the citrus peel, boil it with water for 5 minutes, add a 1:1 hydrochloric acid solution and water reflux For half an hour, filter to remove solids to obtain citrus pectin solution.
The preparation method of the coating composition for producing white-faced cow cardboard according to claims 1-7, the preparation steps are as follows:

Mix part of kaolin, calcium carbonate and sodium polyacrylate, stir at 1600r/min for 8min, after stirring, the stirring speed is reduced to 1000r/min, add oxidized konjac glucomannan citrus pectin, anionic styrene butadiene latex in sequence For nano-modified soybean protein, stir for 10 minutes after each component is added, and finally add carboxymethyl cellulose, polyethylene glycol, glyoxal, silicone defoamer, sodium hydroxide, and each component. Stir for 4 minutes after dividing to prepare the coating.
Use of the coating composition for producing white-faced cow cardboard according to any one of claims 1-7 in the preparation of coated white paper
Coated whiteboard paper prepared from the coating composition for producing white-faced cow cardboard according to any one of claims 1-7.