Sulfate lignin modified urea resin adhesive and preparation method thereof

A technology of sulfate lignin and urea-formaldehyde resin glue, applied in the direction of adhesive, aldehyde/ketone condensation polymer adhesive, adhesive type, etc., to achieve the effect of ensuring comprehensive performance, low formaldehyde emission and high bonding strength

Active Publication Date: 2018-09-14
CHANGSHU INSTITUTE OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] One purpose of the present invention is to solve the problem that traditional alkali lignin or lignosulfonate modified urea-formaldehyde resin adhesives cannot satisfy plywood formaldehyde emission to reach E 0 A kraft lignin modified urea-formaldehyde resin adhesive is provided to meet the use conditions of Class II plywood standard and bonding strength

Method used

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  • Sulfate lignin modified urea resin adhesive and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Add 74.5 grams of formaldehyde solution with a mass percentage concentration of 37% into a 500 mL four-necked flask, stir and heat up to 45 ° C, adjust the pH to 6.17 with a mass percentage concentration of 2% and 5% NaOH solution, and add the first batch of urea 27.5 grams , stir and heat up to 85°C, keep warm for 35min;

[0034] It is 8.55 to adjust pH with the NaOH solution of mass percentage concentration 20%, add the second batch of urea 10 grams, add 5 grams of kraft lignin again, then immediately adjust pH with the NaOH solution of mass percentage concentration 20% to be 8.86, then add poly Vinyl alcohol 0.5g, react for 40min;

[0035] Adjust the pH to 5.36 with a formic acid solution with a concentration of 40% by mass, add a third batch of 8.5 grams of urea, and react for 18 minutes;

[0036] Adjust the pH to 8.65 with a NaOH solution with a concentration of 20% by mass, add the fourth batch of 4 grams of urea and 1 gram of melamine, and react for another 30 m...

Embodiment 2

[0039] Add 76 grams of formaldehyde solution with a mass percentage concentration of 37% into a 500 mL four-neck flask, stir and heat up to 45°C, adjust the pH to 6.26 with a mass percentage concentration of 2% and 5% NaOH solution, and add the first batch of urea 29 grams , stir and heat up to 85°C, keep warm for 40min;

[0040] It is 8.68 to adjust pH with the NaOH solution of mass percentage concentration 20%, add the second batch of urea 9 grams, add 4 grams of kraft lignin again, then immediately adjust pH with the NaOH solution of mass percentage concentration 20% to be 8.78, then add poly Vinyl alcohol 0.6g, react for 38min;

[0041] Adjust the pH to 5.27 with a formic acid solution with a concentration of 40% by mass, add a third batch of 9 grams of urea, and react for 16 minutes;

[0042] Adjust the pH to 8.50 with a NaOH solution with a mass percentage concentration of 20%, add the fourth batch of 3 grams of urea and 1.25 grams of melamine, and react for another 35 ...

Embodiment 3

[0045] Add 77 grams of formaldehyde solution with a mass percentage concentration of 37% into a 500 mL four-neck flask, stir and heat up to 45°C, adjust the pH to 6.34 with a mass percentage concentration of 2% and 5% NaOH solution, and add the first batch of urea 30 grams , stir and heat up to 85°C, keep warm for 38min;

[0046] It is 9.15 to adjust pH with the NaOH solution of mass percentage concentration 20%, add the second batch of urea 7.5 grams, add 6 grams of kraft lignin again, then immediately adjust pH with the NaOH solution of mass percentage concentration 20% to be 8.50, then add poly Vinyl alcohol 0.8g, react for 37min;

[0047] Adjust the pH to 5.15 with a formic acid solution with a mass percentage concentration of 40%, add the third batch of urea 7.5 grams, and react for 14 minutes;

[0048] Adjust the pH to 8.90 with a 20% NaOH solution by mass percentage, add the fourth batch of 5 grams of urea and 1.50 grams of melamine, and react for another 40 minutes; ...

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Abstract

The invention belongs to the technical field of urea resin adhesive, and particularly relates to sulfate lignin modified urea resin adhesive and a preparation method thereof. The adhesive is preparedfrom the following raw materials in parts by weight: 100 parts of urea, 149 to 154 parts of formaldehyde solution, 8 to 15 parts of sulfate lignin, 2 to 3 parts of melamine, 1 to 2 parts of polyvinylalcohol, 0.36 to 0.41 part of alkaline catalyst, and 0.28 to 0.32 part of acidic catalyst. By selecting the sulfate lignin modified urea resin and adopting a weak acid-weak alkali-weak acid-weak alkali synthetic process, the content of a first portion of urea, a second portion of urea, a third portion of urea and a third portion of urea are reasonably configured, so that more dimethylol urea can be generated, the adhesion strength can be improved, little urea is added at the last time, the un-reacted free formaldehyde can be captured, the formaldehyde emission of the prepared plywood is ensured to reach grade E0, and the adhesion strength can reach the type-II plywood standard.

Description

technical field [0001] The invention belongs to the technical field of urea-formaldehyde resin adhesives, and in particular relates to a sulfate lignin modified urea-formaldehyde resin adhesive and a preparation method thereof. The adhesive is suitable for the adhesive required for plywood processing. Background technique [0002] Urea-formaldehyde resin (UF) has many advantages such as rich source of raw materials, low cost, fast curing, good operability, high bonding strength, simple manufacture and excellent comprehensive performance. More than 90% of the amount of glue used. However, due to the high content of free formaldehyde in UF, it has caused problems such as environmental pollution and human health. At the same time, it also makes UF adhesives have low water resistance and high brittleness after curing. Therefore, reducing the free formaldehyde content in UF adhesives and improving the comprehensive performance of UF adhesives are the most promising research dire...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09J161/32C08G12/40
CPCC08G12/40C09J161/32
Inventor 俞丽珍陈培军吴懂飞陈希腾左晓兵周弟
Owner CHANGSHU INSTITUTE OF TECHNOLOGY
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