CN1696181A - Surface modification method of sodium polyacrylate water-absorbing resin - Google Patents

Abstract

A process for modifying the surface of hydroscopic sodium polyacrylate resin in order to improve its water permeability, hydroscopic speed, water-preserving nature and gel strength includes preparing the treating liquid A from methanol or ethanol, dichloroisopropanol or epoxy chloropropane and DMP-30 through mixing and stirring, preparing the treating liquid B from hot deionized water, multi-valence metal salt, and the second cross-coupling agent through stirring, stirring hydroscopic resin while sequentially spraying the treating agent A and B, and cross-linking reaction.

Description

Surface modification method of sodium polyacrylate water-absorbing resin

Field

The invention relates to the production field of sodium polyacrylate water-absorbent resin, in particular to a method for surface modification of sodium polyacrylate water-absorbent resin.

Background technique

Sodium polyacrylate water-absorbent resin, due to its excellent water absorption, has been successfully added to various papers and fibers for many years to manufacture hygienic products with excellent performance, such as baby diapers, sanitary napkins, etc., in agriculture, It has broad application prospects in various aspects such as industry, construction, medicine, daily necessities, food, and light industry.

There are many ways to produce water-absorbent resins, such as: (1) Synthetic water-absorbent resins are easy to absorb moisture and become damp in the air, stick to each other and form a group, and have poor liquid permeability. , resulting in a significant reduction in the water absorption rate and water absorption speed, which affects the actual water absorption performance of the water-absorbent resin. (2) The resin produced by the aqueous solution polymerization method is convenient and fast, but the water-absorbing resin produced by the aqueous solution polymerization needs to be surface-treated to make it have better performance. In order to obtain high-quality water-absorbing materials, appropriate methods must be adopted to improve performance. But there is no effective surface treatment method at present.

Contents of the invention

The object of the present invention is to provide a method for surface modification of sodium polyacrylate water-absorbent resin, which can significantly improve the liquid permeability, water absorption speed, water retention, Increased gel strength to obtain water-absorbent materials with good thermal stability and excellent comprehensive performance.

The technical scheme of the present invention is: the surface modification method of sodium polyacrylate water-absorbing resin, which is characterized in that the steps are as follows:

1), preparation of treatment solution A:

Choose methanol, ethanol, isobutanol, acetone, pentanone any one or a mixture of two or more as a dispersant; choose dichloroisopropanol, epichlorohydrin, glycerin, butylene glycol, diglycidyl ether, Any one of bisphenol A epoxy, ethylene glycol, diglycidol or epoxy resin is used as a cross-linking agent, and DMP-30 is used as a cross-linking accelerator; put the dispersant, cross-linking agent, and cross-linking accelerator in a glass container Stir in medium to prepare treatment solution A;

2), preparation of treatment solution B:

Put the deionized water in a glass container and heat it to 70°C-120°C, weigh the polyvalent metal salt and the second crosslinking agent, add it into the above deionized water and stir, and prepare the treatment solution B;

3) Treatment of the water-absorbing resin by the treatment liquid:

Take a certain amount of water-absorbing resin and place it in a high-speed mixer. While stirring, spray the treatment solution A and treatment solution B on the surface of the water-absorbing resin in sequence. After stirring, put the resin in a tray and heat it in an oven for cross-linking reaction. The reaction temperature is 100-135° C., and the reaction time is 90-120 minutes, that is, the surface modification of the sodium polyacrylate water-absorbing resin is completed.

Aforesaid dispersant adopts ethanol;

Aforesaid linking agent adopts epichlorohydrin;

The aforementioned polyvalent metal salt adopts aluminum salt;

The second crosslinking agent adopts polyhydric alcohol;

Therefore, the beneficial effect of the present invention is: the present invention is divided into two stages, using different surface treatment agents to coat the water-absorbing resin, through the optimization of the surface treatment agent, combined with the control of the surface cross-linking reaction conditions, the water-absorbing capacity does not occur In the case of a significant decrease, the liquid permeability, water absorption speed, water retention, and gel strength of the resin are significantly improved, and a water-absorbing material with good thermal stability and excellent comprehensive performance is obtained.

The performance and surface morphology of the modified resin obtained:

1. Performance comparison of modified resins

sample Saline absorption ratio g/ Water absorption speed Particle dispersion Particle surface dryness Liquid permeability Comparative example 1 64.2 slow Adhesive into a group free water on the surface Difference Example 1 57.4 quick well dispersed dry good Example 2 57.7 faster Good dispersion drier better Example 3 57.3 quick Good dispersion dry good Example 4 57.5 faster Good dispersion dry better Example 5 54.3 quick well dispersed dry good Example 6 57.6 quick well dispersed dry good Example 7 56.8 quick well dispersed dry better

2. For comparison of surface morphology of modified products, see attached drawings 1-5.

Description of drawings

Fig. 1 is the SEM of the surface morphology of the water-absorbing resin of Example 1 of the present invention;

Fig. 2 is an SEM of the surface morphology of the existing water-absorbent resin.

Detailed ways

The surface modification method of sodium polyacrylate water-absorbing resin has the following steps:

1), preparation of treatment solution A:

Methanol was selected as the dispersant, epichlorohydrin was selected as the cross-linking agent, and DMP-30 was used as the cross-linking accelerator; the dispersant, cross-linking agent, and cross-linking accelerator were placed in a glass container and stirred to prepare treatment liquid A;

2), preparation of treatment solution B:

Put deionized water in a glass container and heat to 90°C, weigh aluminum sulfate or aluminum sulfate aluminum oxide and the second crosslinking agent glycerin, add to the above deionized water and stir, and prepare treatment solution B;

3) Treatment of the water-absorbing resin by the treatment liquid:

Take 60-100KG of water-absorbing resin and place it in a mixer at 200-380 rpm. While stirring, spray the treatment solution A and treatment solution B on the surface of the water-absorbing resin in sequence. After stirring, put the resin into the tray and enter The cross-linking reaction is carried out by heating in an oven, the reaction temperature is 120° C., and the reaction time is 100 minutes, that is, the surface modification of the sodium polyacrylate water-absorbent resin is completed.

Claims (4)

1. A method for surface modification of sodium polyacrylate water-absorbing resin, characterized in that the steps are as follows: 1), preparation of treatment solution A: Choose methanol, ethanol, isobutanol, acetone, pentanone any one or a mixture of two or more as a dispersant; choose dichloroisopropanol, epichlorohydrin, glycerin, butylene glycol, diglycidyl ether, Any one of bisphenol A epoxy, ethylene glycol, diglycidol or epoxy resin is used as a cross-linking agent, and DMP-30 is used as a cross-linking accelerator; put the dispersant, cross-linking agent, and cross-linking accelerator in a glass container Stir in medium to prepare treatment liquid A; 2), preparation of treatment solution B: Put the deionized water in a glass container and heat it to 70°C-120°C, weigh the polyvalent metal salt and the second crosslinking agent, add it into the above deionized water and stir, and prepare the treatment solution B; 3) Treatment of the water-absorbent resin by the treatment liquid: Take a certain amount of water-absorbing resin and place it in a high-speed mixer. While stirring, spray the treatment solution A and treatment solution B on the surface of the water-absorbing resin in sequence. After stirring, put the resin in a tray and heat it in an oven for cross-linking reaction. The reaction temperature is 100-135° C., and the reaction time is 90-120 minutes, that is, the surface modification of the sodium polyacrylate water-absorbing resin is completed. 2. The method for modifying the surface of sodium polyacrylate water-absorbent resin according to claim 1, characterized in that ethanol is used as the dispersant. 3. The method for surface modification of sodium polyacrylate water-absorbent resin according to claim 1, characterized in that epichlorohydrin is used as the cross-linking agent. 4. The method for modifying the surface of sodium polyacrylate water-absorbent resin according to claim 1, characterized in that the polyvalent metal salt is aluminum salt.

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