CN101899800A - Application of water glass compound starch as surface sizing agent to improve ring compressive strength of paper and paperboard - Google Patents

Abstract

The invention relates to a surface sizing agent for improving the ring compressive strength of paper and cardboard, which is characterized in that: the surface sizing agent is compounded with water glass or water glass and a curing agent and mixed with surface sizing starch in different proportions compounded. The compounding ratio of water glass and curing agent is 0-100% by weight of water glass; the compounding ratio of water glass and surface sizing starch is 99:1-1:99. The surface sizing agent sizing the surface of paper and paperboard can greatly improve the ring crush strength of paper and paperboard. On the one hand, it can improve the grade of the product; on the other hand, it can reduce the quantity and cost of the product without changing the quality of the product.

Description

Application of water glass compound starch as surface sizing agent to improve ring compressive strength of paper and paperboard

1. Technical field:

The invention relates to the technical field of surface sizing agents, in particular to a surface sizing agent for improving the ring compressive strength of paper and cardboard

2. Background technology:

Corrugated box is an excellent green packaging material, which can replace wood and plastic with paper, and paper materials can be recycled and reused. It has been valued by the environmental protection department and favored by the public, and has a good development prospect. The future development trend of the corrugated box industry is to develop corrugated base paper in the direction of low weight, high strength and light weight. The domestic consumption of high-strength corrugated base paper is very large, and we should vigorously develop local high-strength corrugated base paper and reduce the amount of imports.

The ring crush strength enhancers currently used for paper and paperboard mainly include: starch chemical additives, polyacrylamide (PAM) type enhancers, copolymer emulsion type enhancers, and starch and acrylamide graft copolymers.

Starch chemical additives used for corrugated base paper and cardboard reinforcement mainly include anionic starch, cationic starch and spray starch; polyacrylamide-type strengthening agents include cationic polyacrylamide (CPAM); cationic emulsion-type strengthening agents for papermaking include benzene Cationic copolymers of ethylene, acrylate, acrylamide, and quaternary ammonium salt emulsion polymerization; anionic emulsions include polyvinyl acetate; these strengthening agents have limited improvement in the stiffness and ring compression strength of paper and paperboard, and are added to pulp. There is a disadvantage that it will increase the pollution load of pulp wastewater to the environment, and the increasing sticky matter in the closed cycle of the system will also increase the number of paper breaks of the paper machine.

For corrugated base paper and container board, in order to obtain high ring compressive strength, surface strength and water resistance, surface sizing must be used. Surface sizing agents used for reinforcement can be roughly divided into two categories: starch-based surface sizing agents and synthetic surface sizing agents. At present, the commonly used starch surface sizing agents in my country are oxidized starch and phosphate starch, and now cationic oxidized starch and hydroxypropyl starch are also used as surface sizing starches; synthetic surface sizing agents mainly include polyvinyl alcohol (PVA), Carboxymethyl cellulose (CMC), fluoropropylene-based polymer compounds; and the combined use of starch-based surface sizing agents and synthetic surface sizing agents. This kind of surface sizing agent is more effective in improving the surface strength, printability and sheet shape stability of paper. On the one hand, because the viscosity of starch is limited, the amount of sizing can only reach 3-5g/ ^m2 per side , It is more difficult to increase the amount of sizing. On the other hand, after the starch sizing is dried and hardened, the stiffness of the starch glue layer itself is not enough, and it is limited to greatly increase the ring compressive strength of paper and cardboard. Therefore, it is very necessary to provide a special surface sizing agent which is very effective in improving the ring compressive strength of paper and cardboard.

3. Contents of the invention:

The purpose of the present invention is to provide a surface sizing agent for improving the ring compressive strength of paper and cardboard, which can overcome the shortcomings of insufficient ring compressive strength of paper and cardboard after the existing surface sizing agent is sized.

In order to achieve the above object, technical scheme of the present invention is:

1. The surface sizing agent is made of water glass or water glass and curing agent compounded and then mixed with surface sizing starch.

2. The mixing ratio of water glass and curing agent is 99:1~1:99.

3. The compounding ratio of the surface sizing agent and the surface sizing starch is 99:1-1:99.

4. Water glass can choose different modulus and different types of water glass.

5. Measurement of ring crush strength of paper and cardboard.

Measure the ring crush strength of paper and cardboard according to the test method of cardboard ring crush strength stipulated in the national standard GB/T2679.8-1995.

The ring compressive strength is calculated as follows:

R=F/152

In the formula, R-ring compressive strength, kN/m; F-the average value of the crushing force of the sample, N; 152-the length of the sample.

The ring pressure index is calculated according to the following formula:

_Rd = 1000R/g

In the formula, Rd-ring pressure index, N·m/g; R-ring pressure strength, kN/m; g-quantity, g/m ² ; 152-sample length.

4. Specific implementation

Example 1:

Get 10 grams of corn oxidized starch to gelatinize. After the starch is gelatinized, it is compounded with 5 grams of water glass with a modulus of 3.25 and mixed evenly. Apply surface sizing and dry at 105°C for a few minutes. The increase in ring compressive strength is as follows:

Sizing amount, g/m2 0 6 7 8 9 10 Ring pressure index, N*m/g 6.3 7.74 8.7 9.3 8.87 7.25 Enhancement percentage, % 0 22.9 38.1 47.6 40.8 15.1

Example 2:

Get 10 grams of corn oxidized starch to gelatinize. After the starch is gelatinized, compound with 10 grams of water glass with a modulus of 3.25 and mix evenly. Apply surface sizing and dry at 105°C for a few minutes. The increase in ring compressive strength is as follows:

Sizing amount, g/m2 0 7 8 10 12 13 Ring pressure index, N*m/g 6.3 9.7 10 9.3 8.13 7.7 Enhancement Percentage% 0 54.0 58.7 47.6 29.0 22.2

Example 3:

Get 5 grams of corn oxidized starch for gelatinization. After the starch is gelatinized, compound with 10 grams of water glass with a modulus of 3.25 and mix evenly. Apply surface sizing and dry at 105°C for a few minutes. The increase in ring compressive strength is as follows:

Sizing amount, g/m2 0 7 8 11 13 14

Ring pressure index, N*m/g 6.3 8.09 10.64 10.15 9.04 8.53 Enhancement percentage, % 0 28.9 68.9 61.1 43.5 35.4

Example 4:

Get 5 grams of corn oxidized starch for gelatinization. Take 10 grams of water glass with a modulus of 3.25 and mix evenly with 1 gram of sodium fluorosilicate, and then mix it with the above-mentioned gelatinized starch and mix evenly. Apply surface sizing and dry at 105°C for a few minutes. The increase in ring compressive strength is as follows:

Sizing amount, g/m2 0 6 7 8 9 10 Ring pressure index, N*m/g 6.3 9.64 9.13 9.08 8.78 8 Enhancement Percentage% 0 53.0 44.9 44.1 39.4 26.9

Example 5:

Get 10 grams of corn oxidized starch to gelatinize. Take 10 grams of water glass with a modulus of 3.25 and 1 gram of sodium fluorosilicate and mix them evenly, and then mix them with the above-mentioned gelatinized starch and mix them evenly. Apply surface sizing and dry at 105°C for a few minutes. The increase in ring compressive strength is as follows:

Sizing amount, g/m2 0 6 6.5 7 7.3 8 Ring pressure index, N*m/g 6.3 9.3 8.35 7.5 7.4 7 Enhancement percentage, % 0 47.6 32.5 19.0 17.5 11.1

Example 6:

Get 10 grams of corn oxidized starch to gelatinize. Take 5 grams of water glass with a modulus of 3.25 and 1 gram of sodium fluorosilicate and mix them evenly, and then mix them with the above-mentioned gelatinized starch and mix them evenly. Apply surface sizing and dry at 105°C for a few minutes. The increase in ring compressive strength is as follows:

Sizing amount, g/m2 0 6.5 7 8 9 10 Ring pressure index, N*m/g 6.3 7.34 7.83 8.27 7.86 7.65 Enhancement percentage, % 0 16.5 24.2 31.3 24.8 21.4

Example 7:

Get 5 grams of corn oxidized starch for gelatinization. Take 5 grams of water glass with a modulus of 3.25 and 1 gram of sodium fluorosilicate and mix them evenly, and then mix them with the above-mentioned gelatinized starch and mix them evenly. Apply surface sizing and dry at 105°C for a few minutes. The increase in ring compressive strength is as follows:

Sizing amount, g/m2 0 6 6.5 7 7.5 8 Ring pressure index, N*m/g 6.3 9.08 8.16 7.4 7 6.8 Enhancement percentage, % 0 44.1 29.5 17.5 11.1 7.9

Claims (15)

1. Cypres that is used to improve paper and cardboard ring crush intensity is characterized in that: this Cypres is to be 0～100% curing agent and surface sizing starch is composite mixes by waterglass or waterglass and its percentage by weight.

2. Cypres according to claim 1 is characterized in that: the compound proportion of waterglass and surface sizing starch is 99: 1～1: 99.

3. Cypres according to claim 1 is characterized in that: the modulus of water glass scope comprises 1～100.

4. Cypres according to claim 1 is characterized in that: waterglass comprises sodium silicate (Na ₂OnSiO ₂), KP1 (k ₂OnSiO ₂), lithium silicate (Li ₂OnSiO ₂), potassium receives waterglass (k ₂ONa ₂OnSiO ₂).

5. Cypres according to claim 1 is characterized in that: surface sizing starch comprises one or more the mixture in ative starch, enzyme converted starch, denaturated starch by acid, oxidized starch, esterification starch, etherification starch, the pre-gelatinized starch.

6. according to the described oxidized starch of claim 5, it is characterized in that oxidized starch comprises hypochlorite oxidation starch and hydrogen peroxide oxidation starch.

7. according to the described esterification starch of claim 5, it is characterized in that esterification starch comprises starch phosphate monoester, starch acetate, starch xanthate, starch alkenyl succinic acid ester.

8. according to the described etherification starch of claim 5, it is characterized in that etherification starch comprises hydroxyalkyl starch, carboxymethyl starch, cationic starch.

9. Cypres according to claim 1 is characterized in that: curing agent comprises one or more the mixture in condensed phosphate, inorganic acid, metal oxide, soluble metal salt, organic compound, the silicofluoride.

10. condensed phosphate curing agent according to claim 9 is characterized in that: the condensed phosphate curing agent is specific to comprise one or more mixture in polymer phosphate aluminium, aluminum phosphate, trbasic zinc phosphate and the magnesium phosphate.

11. inorganic acid curing agent according to claim 9 is characterized in that: the inorganic acid curing agent is specific to comprise one or more mixture in hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, the acetic acid.

12. metal oxide curing agent according to claim 9 is characterized in that: metal oxide curing agent is specific to comprise one or more mixture in zinc oxide, magnesia, the calcium oxide.

13. soluble metal salt curing agent according to claim 9 is characterized in that: the soluble metal salt curing agent is specific to comprise one or more mixture in carbonate, sulfate and the chloride of polyvalent metals such as zinc, calcium, magnesium, aluminium.

14. the organic compound curing agent of solubility according to claim 9 is characterized in that: organic compound is specific comprise glyoxal, one or more mixture in the ethylene glycol bisthioglycolate cellulose acetate, triacetyl glycerine, ethyl acetate.

15. the silicofluoride curing agent of solubility according to claim 9 is characterized in that: the silicofluoride curing agent is specific to comprise one or more mixture in prodan, potassium fluosilicate, magnesium fluosilicate, the calcium fluosilicate.