Method for preparing oxidization starch modified urea-formaldehyde resin

A technology for oxidizing starch and urea-formaldehyde resin, which is applied in the field of modification and preparation of urea-formaldehyde resin, can solve the problems of increased production cost and expensive raw materials, and achieves the effects of good stability, reducing free aldehyde content and increasing cross-linking reaction.

Inactive Publication Date: 2008-02-13
JIANGSU UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Forest product industry, 2003, 30 (I): 11-14 has reported a kind of development and the application of indoor wood-based panel and low formaldehyde release urea-formaldehyde resin adhesive, although t

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Under vigorous stirring, weigh 405 g of 37% formaldehyde aqueous solution and 0.004 g of catalytic ammonia water, add them into a three-necked flask and mix them. After mixing evenly, add 60g of urea, 1653g of water and 2.1g of perchloric acid oxidized starch, heat up to 45°C, add 0.02g of acetic acid during reflux, and continue the reaction for 40 minutes to maintain the pH of the solution at about 6.5. Then use 0.02g of sodium bicarbonate to adjust the pH value to about 7.2, continue to stir for 15 minutes, then stop heating, and the reaction ends to obtain a modified urea-formaldehyde resin product UF1 with a solid content of 10%.

Embodiment 2

[0018] Under vigorous stirring, 243 g of 37% formaldehyde solution and 0.04 g of catalyst ammonium chloride were weighed, added to a three-necked flask and mixed. After mixing evenly, add 60g of urea, 10g of water and 7.5g of hydrogen peroxide oxidized starch, heat up to 85°C, add 0.1g of formic acid during the reflux process, and continue the reaction for 1.5 hours to maintain the pH value of the solution at about 4.8. Then adjust the pH value to about 8.2 with 0.1g ammonium chloride, stop heating after continuing to stir for 15 minutes, and the reaction ends to obtain a modified urea-formaldehyde resin product UF2 with a solid content of 49%.

Embodiment 3

[0020] Under strong stirring, 105 g of 37% formaldehyde solution and 0.03 g of catalyst diethanolamine were weighed, added to a three-necked flask and mixed. After mixing evenly, add 60g of urea and 7g of water, raise the temperature to 90°C, add 0.2g of formic acid during the reflux process, and continue the reaction for 2 hours to maintain the pH value of the solution at about 3.0. Then adjust the pH value to about 9.8 with 0.2g sodium bicarbonate, add 9.9g potassium permanganate oxidized starch, stop heating after continuing to stir for 15 minutes, and the reaction ends to obtain a modified urea-formaldehyde resin product UF3 with a solid content of 60%.

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PUM

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Abstract

The invention relates to a preparation technology of the modified urea-formaldehyde resin; with the strong agitation and the presence of the catalyst, the urea, formaldehyde, water and oxidized starch are added at a time according to the stoichiometric ratio; or first the urea and formaldehyde are used to make the urea-formaldehyde resin with the presence of the catalyst, and then the oxidized starch is used to do the cross-linking step-by-step polymerization; after mixing well, the temperature is raised to be 45 to 110 Celsius system; the acid of a certain amount in the return process is added; the reaction is kept for 40 minutes to 3 hours at a constant temperature; the pH value of the solution is maintained between 3.0 and 6.5. Then the alkaline substance is used to adjust the pH value to be between 7.2 and 9.8; the method is to continue to stir for 15 minutes and stop heating; after the reaction, the modified urea-formaldehyde resin product can be made with a certain solid content. The invention has the advantages of the reduction of the cost and at the same time, the increase of the cross-linking reaction, which further lowers the free-formaldehyde content in the resin, lengthens the time for storage, and reduces the environmental pollution. The product produced in the invention has the advantages of a good stability, a high solid content, the saving of energy and so on.

Description

technical field [0001] The invention relates to a modified preparation technology of urea-formaldehyde resin, in particular to a preparation method of urea-formaldehyde resin modified by oxidized starch. The modified urea-formaldehyde resin has the properties of stable storage, excellent heat resistance, low free formaldehyde content, low methylol content, good adhesive strength and the like. Background technique [0002] Urea-formaldehyde resin (UF) glue is an adhesive widely used in industries such as bamboo and wood processing, paper bonding, tempered coatings, etc. In recent years, people's demand for environmentally friendly adhesives is increasing. Adhesives are mostly high molecular polymers containing benzene rings and formaldehyde monomer structures. These harmful ingredients will slowly release strong irritating toxic gases during production and practical application, irritating the eyes and trachea. Among them, formaldehyde not only It has stimulating effects on ...

Claims

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Application Information

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IPC IPC(8): C08G12/40C08G12/36
Inventor 邱凤仙孙丽丽杨冬亚
Owner JIANGSU UNIV
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