Preparation method of wet strength agent for papermaking

Abstract

The invention relates to a preparation method of a wet strength agent for papermaking and belongs to the technical field of preparation of wet strength agents. Chitosan is subjected to swelling treatment with anhydrous ethanol firstly and then modified with maleic anhydride and phosphoric acid, and modified chitosan is obtained; modified chitosan reacts with isocyanate, and a chitosan polymer is obtained; hydroxyl and amino in the chitosan polymer can form hydrogen bonds with cellulose in paper and can perform bridging and film formation among cellulose to enhance the wet strength and the tearing strength of paper; then, methyl benzene sulfonic chloride and other substances are utilized to modify hydroxypropyl guar gum, and modified guar gum is obtained; finally, modified guar gum is mixed with a chitosan polymer concentrated solution and other substances for ageing, and the wet strength agent for papermaking is obtained. The wet strength agent solves the problem that a conventional wet strength agent cannot improve the wet strength and the tear resistance of paper, improves the wet strength and the tear resistance of paper greatly, and can realize expanded production.

Description

technical field

[0001] The invention relates to a method for preparing a wet strength agent for papermaking, and belongs to the technical field of wet strength agent preparation. Background technique

[0002] As a raw material for papermaking, cellulose has the characteristics of being hydrophilic. When the paper is wetted with water, the cellulose will lose its corresponding strength. In the process of industrial papermaking, if a wet strength agent is added, the wet strength of the paper can be significantly improved. tensile strength. Wet strength agent is an important papermaking chemical that can not only improve the quality of paper sheets, but also make irreversible changes in the dry strength of paper sheets in a dry state and the wet strength after soaking. A long time ago, the way people endowed paper with wet strength was to put the paper into sulfuric acid to make it parchmentized. The parchmented paper fibers were denatured and bonded. After the treated paper w...

Examples

example 1

[0018] First weigh 200g of chitosan and add it to the flask, place the flask in a water bath, heat up to 90°C, then add 400mL of absolute ethanol, stir and mix for 30min with magnetic force, after the chitosan is completely swollen, add 30g of horseradish acid anhydride and 0.5g phosphoric acid, stirred and reacted for 2h, filtered, collected the filter cake, and washed 5 times with deionized water to obtain modified chitosan; the above modified chitosan was added to the flask, and the flask was placed in the oil In the bath, heat up to 130°C, then add 300mL of acetonitrile, stir for 5min, then add 30g of isocyanate and 0.5g of dibutyltin dilaurate, stir for 3h, then collect the reactant and place it in a distillation device. Heating to 90°C, distilling for 50min, transferring the distilled liquid to a rotary evaporator, and rotary evaporating to 3 / 4 of the original volume to obtain a chitosan polymer concentrate, which is set aside; weigh 20g of hydroxypropyl guar Put the glu...

example 2

[0021] First weigh 100g of chitosan and add it to the flask, place the flask in a water bath, heat up to 80°C, then add 300mL of absolute ethanol, stir and mix for 20min with magnetic force, after the chitosan is completely swollen, add 20g of horseradish acid anhydride and 0.3g phosphoric acid, stirred and reacted for 1 hour, filtered, collected the filter cake, and washed 3 times with deionized water to obtain modified chitosan; the above-mentioned modified chitosan was added to the flask, and the flask was placed in the oil In the bath, heat up to 120°C, add 250mL of acetonitrile, stir for 3 minutes, then add 20g of isocyanate and 0.3g of dibutyltin dilaurate, stir and react for 2 hours, collect the reactants, and place them in a distillation device. Heating to 85°C, distilling for 40min, transferring the distilled liquid to a rotary evaporator, and rotary evaporating to 3 / 4 of the original volume to obtain a chitosan polymer concentrate, which is set aside; weigh 10g of hyd...

example 3

[0024] First weigh 150g of chitosan and add it to the flask, place the flask in a water bath, heat up to 85°C, then add 350mL of absolute ethanol, stir and mix for 25min with magnetic force, after the chitosan is completely swollen, add 25g of Malay acid anhydride and 0.4g phosphoric acid, stirred and reacted for 1h, filtered, collected the filter cake, and washed 4 times with deionized water to obtain modified chitosan; the above-mentioned modified chitosan was added to the flask, and the flask was placed in the oil In the bath, heat up to 124°C, then add 260mL of acetonitrile, stir for 4min, then add 25g of isocyanate and 0.4g of dibutyltin dilaurate, stir for 2h, collect the reactants, and place them in a distillation device. Heating to 87°C, distilling for 45min, transferring the distilled liquid to a rotary evaporator, and rotary evaporating to 3 / 4 of the original volume to obtain a chitosan polymer concentrate, which is set aside; weigh 15g hydroxypropyl guar Put the glu...

technical field

[0001] The invention relates to a method for preparing a wet strength agent for papermaking, and belongs to the technical field of wet strength agent preparation. Background technique

[0002] As a raw material for papermaking, cellulose has the characteristics of being hydrophilic. When the paper is wetted with water, the cellulose will lose its corresponding strength. In the process of industrial papermaking, if a wet strength agent is added, the wet strength of the paper can be significantly improved. tensile strength. Wet strength agent is an important papermaking chemical that can not only improve the quality of paper sheets, but also make irreversible changes in the dry strength of paper sheets in a dry state and the wet strength after soaking. A long time ago, the way people endowed paper with wet strength was to put the paper into sulfuric acid to make it parchmentized. The parchmented paper fibers were denatured and bonded. After the treated paper w...

Examples

example 1

[0018] First weigh 200g of chitosan and add it to the flask, place the flask in a water bath, heat up to 90°C, then add 400mL of absolute ethanol, stir and mix for 30min with magnetic force, after the chitosan is completely swollen, add 30g of horseradish acid anhydride and 0.5g phosphoric acid, stirred and reacted for 2h, filtered, collected the filter cake, and washed 5 times with deionized water to obtain modified chitosan; the above modified chitosan was added to the flask, and the flask was placed in the oil In the bath, heat up to 130°C, then add 300mL of acetonitrile, stir for 5min, then add 30g of isocyanate and 0.5g of dibutyltin dilaurate, stir for 3h, then collect the reactant and place it in a distillation device. Heating to 90°C, distilling for 50min, transferring the distilled liquid to a rotary evaporator, and rotary evaporating to 3 / 4 of the original volume to obtain a chitosan polymer concentrate, which is set aside; weigh 20g of hydroxypropyl guar Put the glu...

example 2

[0021] First weigh 100g of chitosan and add it to the flask, place the flask in a water bath, heat up to 80°C, then add 300mL of absolute ethanol, stir and mix for 20min with magnetic force, after the chitosan is completely swollen, add 20g of horseradish acid anhydride and 0.3g phosphoric acid, stirred and reacted for 1 hour, filtered, collected the filter cake, and washed 3 times with deionized water to obtain modified chitosan; the above-mentioned modified chitosan was added to the flask, and the flask was placed in the oil In the bath, heat up to 120°C, add 250mL of acetonitrile, stir for 3 minutes, then add 20g of isocyanate and 0.3g of dibutyltin dilaurate, stir and react for 2 hours, collect the reactants, and place them in a distillation device. Heating to 85°C, distilling for 40min, transferring the distilled liquid to a rotary evaporator, and rotary evaporating to 3 / 4 of the original volume to obtain a chitosan polymer concentrate, which is set aside; weigh 10g of hyd...

example 3

[0024] First weigh 150g of chitosan and add it to the flask, place the flask in a water bath, heat up to 85°C, then add 350mL of absolute ethanol, stir and mix for 25min with magnetic force, after the chitosan is completely swollen, add 25g of Malay acid anhydride and 0.4g phosphoric acid, stirred and reacted for 1h, filtered, collected the filter cake, and washed 4 times with deionized water to obtain modified chitosan; the above-mentioned modified chitosan was added to the flask, and the flask was placed in the oil In the bath, heat up to 124°C, then add 260mL of acetonitrile, stir for 4min, then add 25g of isocyanate and 0.4g of dibutyltin dilaurate, stir for 2h, collect the reactants, and place them in a distillation device. Heating to 87°C, distilling for 45min, transferring the distilled liquid to a rotary evaporator, and rotary evaporating to 3 / 4 of the original volume to obtain a chitosan polymer concentrate, which is set aside; weigh 15g hydroxypropyl guar Put the glu...