阅读说明：本技术 一种改性玉米秸穰造纸干强剂及使用方法 (Modified corn straw papermaking dry strength agent and use method thereof ) 是由 张敏盛 张益盛 潘玉丽 于 2020-12-10 设计创作，主要内容包括：本发明公开了一种改性玉米秸穰造纸干强剂,包括以下重量百分比原料：改性玉米秸穰淀粉1-2％,2,2,6,6-四甲基哌啶氧自由基2-3％,磷酸酯淀粉1-2％,阳离子聚季铵盐45-70％,丙烯酰胺9-12％,丙烯酸9-12％,丙烯酸酯17-20％,引发1.2-2.4％,余量为pH调节剂。本发明制备所得的纸张的干纸强度大幅度提高,其中耐破指数提高15％-30％,耐折度提高50％,纸张环压指数提高15％～20％,纤维填料留着率提高15％以上。(The invention discloses a modified corn stalk paper-making dry strength agent, which comprises the following raw materials in percentage by weight: 1-2% of modified corn stalk starch, 2-3% of 2,2,6, 6-tetramethyl piperidinyloxy free radical, 1-2% of phosphate starch, 45-70% of cationic polyquaternary ammonium salt, 9-12% of acrylamide, 9-12% of acrylic acid, 17-20% of acrylate, 1.2-2.4% of initiator and the balance of pH regulator. The dry paper strength of the paper prepared by the method is greatly improved, wherein the bursting index is improved by 15-30%, the folding endurance is improved by 50%, the ring crush index of the paper is improved by 15-20%, and the retention rate of the fiber filler is improved by more than 15%.)

1. The modified corn straw papermaking dry strength agent is characterized by comprising the following raw materials in percentage by weight:

the balance is pH regulator.

2. The modified corn stalk paper-making dry strength agent according to claim 1, characterized in that the corn stalk starch is prepared by the following method:

crushing the corn straw spikes by a crusher, and sieving the crushed corn straw spikes by a 20-mesh sieve; extracting the benzene alcohol for 8-12 h; extracting for 4-8h with NaOH; washing; NaClO treatment (normal temperature, effective chlorine dosage is 7-12%, pH is 2-5, time is 55-80 min); washing; basic H₂O₂(the concentration is 8-16%, the temperature is 50-80 ℃, and the pH value is 9-11) for 6-8 h; washing; obtaining modified corn straw ears; drying at constant temperature of 60 ℃; crushing into powder of 200 meshes to obtain the corn stalk starch.

3. The modified corn stalk paper-making dry strength agent according to claim 1, wherein the pH regulator is one of sodium dihydrogen phosphate or sodium bicarbonate.

4. The modified corn straw papermaking dry strength agent according to claim 1, characterized in that the modified corn straw papermaking dry strength agent is a whitish or transparent viscous liquid.

5. The modified corn straw papermaking dry strength agent according to claim 1, wherein the solid content of the modified corn straw papermaking dry strength agent is 15 ± 1%.

6. The modified corn straw papermaking dry strength agent as claimed in claim 1, characterized in that the viscosity (25 ℃, mPa.s) of the modified corn straw papermaking dry strength agent is 3000-11000.

7. The modified corn stalk papermaking dry strength agent according to claim 1, wherein the water-insoluble content of the modified corn stalk papermaking dry strength agent is less than or equal to 0.01.

8. The modified corn straw papermaking dry strength agent according to claim 1, wherein the pH of the modified corn straw papermaking dry strength agent is 3.5-5.5.

9. The use method of the modified corn straw papermaking dry strength agent according to any one of claims 1 to 8 is characterized in that the modified corn straw papermaking dry strength agent is diluted by 10 to 20 times with clear water and is directly added into a pulping tank, a papermaking pulping tank, an inlet of a sizing pump and an overhead tank.

10. The use method of the modified corn straw papermaking dry strength agent according to any one of claims 1 to 8, characterized in that the modified corn straw papermaking dry strength agent is used for production of coated paper, boxboard paper, paper bag paper and kraft paper.

Technical Field

The invention belongs to the technical field of development and utilization of papermaking green chemicals, and particularly relates to a modified corn straw papermaking dry strength agent.

Background

The waste paper is mostly used for pulping or straw pulp for packaging in China, and the strength of the paperboard is low due to more short fibers in the pulp, so that the improvement of the strength of the paperboard is more and more important. The dry strength of paper or board, which is one of the structural properties of paper, is mainly obtained as a result of bonding between the fibres after the fibre network has been formed and dried, and is mainly determined by the strength of the individual fibres and the degree, number, distribution of the fibre bonds, etc. between the fibres. The dry strength agent is an important chemical for increasing the strength of paper in the paper industry, a plurality of water-soluble polymers which can form hydrogen bond with fibers can be used as the dry strength agent, and the method for improving the strength of paper or paperboard by using the dry strength agent is a very effective method.

Among the dry strength agents currently used, the starch-based dry strength agents account for almost the largest share of the market. Starch is used as a dry strength agent, and the dry strength agent is required to be gelatinized and diluted by steam in the using process, so that the manufactured dry strength agent has poor paper folding strength, ring crush strength and bursting strength. Meanwhile, the original starch has little effect on improving the dry strength of paper, and modified starch is generally added. The modified starch dry strength agent can achieve the best effect only by forming effective and rapid adsorption with fiber, and the charge density and the addition amount of the modified starch dry strength agent are in proper ranges, and simultaneously, the modified starch dry strength agent cannot have side reaction with other additives in the system. When the starch is added in larger amounts, dry strength tends to be increased, but unadsorbed starch will nucleate in the white water system. Since the starch is adsorbed to different components to different degrees and the adsorption is irreversible, it is a technical problem in the art to ensure that the starch is adsorbed to the fiber in an optimal state, i.e., to provide the best strength.

The corn straw is mainly composed of cellulose, hemicellulose, lignin and other fiber components, and is a high-quality papermaking raw material. The corn stalk peel has higher cellulose content, moderate hemicellulose content and higher lignin content than paper, and the high cellulose content ensures high paper pulp yield and good strength performance of the paper sheet; a certain amount of hemicellulose is advantageous for fiber swelling and beating of pulp; the bleaching consumption is reduced when the lignin content is low. However, from the practical situation, the basic theoretical research and the experiment in the aspect are few at home and abroad, and a large exploration space still exists.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a modified corn straw paper-making dry strength agent. The dry strength agent can effectively improve the burst strength and ring crush strength of paper and obviously improve the physical properties of the paper; the dosage is less, and the paper has the functions of retention and drainage, and can reduce the loss of fine fibers in the papermaking process.

The invention adopts the following technical scheme:

the modified corn straw papermaking dry strength agent comprises the following raw materials in percentage by weight:

preferably, the modified corn straw papermaking dry strength agent comprises the following raw materials in percentage by weight:

preferably, the modified corn straw papermaking dry strength agent comprises the following raw materials in percentage by weight:

further, the corn stalk starch is prepared by the following method:

crushing the corn straw spikes by a crusher, and sieving the crushed corn straw spikes by a 20-mesh sieve; extracting the benzene alcohol for 8-12 h; extracting for 4-8h with NaOH; washing; NaClO treatment (normal temperature, effective chlorine dosage is 7-12%, pH is 2-5, time is 55-80 min); washing; treating with alkaline H2O2 (concentration 8-16%, temperature 50-80 deg.C, pH 9-11) for 6-8H; washing; obtaining modified corn straw ears; drying at constant temperature of 60 ℃; crushing into powder of 200 meshes to obtain the corn stalk starch.

Further, 2,2,6, 6-tetramethyl piperidinyloxy free radical can selectively oxidize the primary hydroxyl at the C-6 position of the modified corn stalk starch into carboxyl. Carboxyl is introduced on the surface of the nanofiber through oxidation reaction, the existence and the content of the carboxyl directly influence the swelling property, the absorptivity, the softness and the bonding force among fibers, the retention rate of fine fibers can be improved, the drainage performance of pulp is improved, the good operation of a paper machine system is facilitated, and the strength performance of paper sheets can be obviously improved. Meanwhile, the treated fibers contain carboxyl, and ionic bonding exists, so that hydrogen chain bonding and electrostatic adsorption among the fibers are enhanced.

Further, the pH regulator is one of sodium dihydrogen phosphate and sodium bicarbonate.

Further, the modified corn straw papermaking dry strength agent is a slightly white or transparent viscous liquid.

Furthermore, the phosphate monoester starch has obvious reinforcing effect.

Further, the solid content of the modified corn straw papermaking dry strength agent is 15 +/-1%.

Further, the viscosity (25 ℃, mPa.s) of the modified corn straw papermaking dry strength agent is 3000-11000.

Further, the content of the water-insoluble substances in the modified corn straw papermaking dry strength agent is less than or equal to 0.01.

Further, the pH value of the modified corn straw papermaking dry strength agent is 3.5-5.5.

Further, the modified corn straw papermaking dry strength agent is suitable for production of paper such as coated paper, boxboard paper, paper bag paper, kraft paper and the like.

The invention has the beneficial effects that:

1. the dry paper strength can be greatly improved, wherein the bursting strength index is improved by 15-30%, the folding strength is improved by 50%, the paper ring crush index is improved by 15-20%, and the effect of improving the bursting strength of the craft paper is particularly obvious.

2. The retention rate of the fiber filler is improved by more than 15 percent.

Detailed Description

For better explanation of the present invention, the following specific examples are further illustrated, but the present invention is not limited to the specific examples.

Example 1

The modified corn straw papermaking dry strength agent comprises the following raw materials in percentage by weight:

further, the corn stalk starch is prepared by the following method:

corn straw spike → pulverizer for pulverization → 20 mesh sieve → benzyl alcohol extraction for 8H → NaOH extraction for 4H → washing → NaClO treatment (normal temperature, effective chlorine dosage is 7%, pH 2, time 55min) → washing → alkaline H₂O₂(concentration is 8 percent, temperature is 50 ℃, pH value is 9) for 6h → washing → modified corn straw spike → dried and crushed into 200-mesh powder at constant temperature of 60 ℃.

Diluting the modified corn stalk paper-making dry strength agent by 10 times with clear water, directly adding the diluted agent into a pulping tank, and preparing paper by adopting a conventional technical means.

Example 2

The modified corn straw papermaking dry strength agent comprises the following raw materials in percentage by weight:

further, the corn stalk starch is prepared by the following method:

corn straw spike → pulverizer for pulverization → 20 mesh sieve → 10H of benzyl alcohol extraction → 6H of NaOH extraction → washing → NaClO treatment (normal temperature, effective chlorine dosage is 8%, pH is 3, time is 60min) → washing → alkaline H₂O₂(the concentration is 10 percent, the temperature is 60 ℃, and the pH value is 10) for 7h → washing → modified corn straw spike → drying at the constant temperature of 60 ℃ and crushing into powder of 200 meshes.

Diluting the modified corn stalk paper-making dry strength agent by 15 times with clear water, directly adding the diluted agent into a pulp making pool, and preparing paper by adopting a conventional technical means.

Example 3

The modified corn straw papermaking dry strength agent comprises the following raw materials in percentage by weight:

further, the corn stalk starch is prepared by the following method:

corn straw spike → crusher crushing → rice straw20 mesh sieve → 11H of benzyl alcohol extraction → 7H of NaOH extraction → washing → NaClO treatment (normal temperature, effective chlorine dosage is 9%, pH 4, time 70min) → washing → alkaline H₂O₂(the concentration is 14 percent, the temperature is 65 ℃, and the pH value is 10.5) for 7.5h → washing → modified corn straw spike → drying at the constant temperature of 60 ℃ and crushing into powder of 200 meshes.

Diluting the modified corn stalk paper-making dry strength agent by 17 times with clear water, directly adding the diluted agent into an inlet of a pulp pump, and preparing paper by adopting a conventional technical means.

Example 4

The modified corn straw papermaking dry strength agent comprises the following raw materials in percentage by weight:

further, the corn stalk starch is prepared by the following method:

corn straw spike → pulverizer pulverization → 20 mesh sieve → benzyl alcohol extraction 12H → NaOH extraction 8H → washing → NaClO treatment (normal temperature, effective chlorine dosage 12%, pH 5, time 80min) → washing → alkaline H₂O₂(the concentration is 16 percent, the temperature is 80 ℃, and the pH value is 11) for 8h → washing → modified corn straw spike → 60 ℃ for drying and crushing into powder of 200 meshes.

Diluting the modified corn stalk paper-making dry strength agent by 20 times with clear water, directly adding into a high-level box, and preparing paper by adopting a conventional technical means.

Comparative example 1

The corn stalk paper-making dry strength agent comprises the following raw materials in percentage by weight:

diluting the modified corn stalk paper-making dry strength agent by 10 times with clear water, directly adding the diluted agent into a pulping tank, and preparing paper by adopting a conventional technical means.

Comparative example 2

The corn stalk paper-making dry strength agent comprises the following raw materials in percentage by weight:

diluting the modified corn stalk paper-making dry strength agent by 15 times with clear water, directly adding the diluted agent into a pulp making pool, and preparing paper by adopting a conventional technical means.

Comparative example 3

The corn stalk paper-making dry strength agent comprises the following raw materials in percentage by weight:

diluting the modified corn stalk paper-making dry strength agent by 17 times with clear water, directly adding the diluted agent into an inlet of a pulp pump, and preparing paper by adopting a conventional technical means.

Comparative example 4

The corn stalk paper-making dry strength agent comprises the following raw materials in percentage by weight:

diluting the modified corn stalk paper-making dry strength agent by 20 times with clear water, directly adding into a high-level box, and preparing paper by adopting a conventional technical means.

The burst index, folding endurance and sheet ring crush index of the sheets obtained in examples 1-4 and comparative examples 1-4 were measured according to GB/T454-2002, GB/T457 ISO9001:2000, GB T2679.8-1995 and the results are shown in Table 1.

TABLE 1

As can be seen from table 1, the dry paper strength of the paper sheets prepared in examples 1 to 4 is greatly improved, wherein the bursting index is improved by 15 to 30 percent, the folding endurance is improved by 50 percent, the ring crush index of the paper sheet is improved by 15 to 20 percent, and the retention rate of the fiber filler is improved by more than 15 percent, compared with comparative examples 1 to 4.

The above description is only exemplary of the present invention and is not intended to limit the scope of the present invention, which is defined by the claims appended hereto, as well as the appended claims.