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Modified urea-formaldehyde resin adhesive for concrete formwork and production method of adhesive

A technology of concrete formwork and urea-formaldehyde resin, applied in the direction of adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., to achieve the effect of convenient control of the process and easy operation

Active Publication Date: 2012-03-28
GUANGXI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the related reactants under strong acid are very sensitive to temperature, feeding rate, molar ratio, pH value and residence time, so it is difficult to control the low temperature or add a polymerization inhibitor

Method used

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  • Modified urea-formaldehyde resin adhesive for concrete formwork and production method of adhesive
  • Modified urea-formaldehyde resin adhesive for concrete formwork and production method of adhesive
  • Modified urea-formaldehyde resin adhesive for concrete formwork and production method of adhesive

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] 1. Formula composition

[0021] The molar ratio of formaldehyde to urea is F / U=2.04, 530 parts of formaldehyde (concentration 37%), 197 parts of urea (purity 98%), 65 parts of melamine, 1.4 parts of polyvinyl alcohol, 1 part of hexamethylenetetramine, 2 parts of dicyandiamide.

[0022] 2. Glue making process

[0023] Put 530 parts of formaldehyde solution and 1.4 parts of polyvinyl alcohol into the reaction kettle, start the agitator, start heating and heating, stop heating when the temperature rises to 38-40 °C, and when the temperature inertia rises to 48 °C, use 31-36% hydrochloric acid to adjust the pH value to 1.7-2.0;

[0024] When the temperature rises to 51°C, add 140 parts of the first batch of urea evenly within 7-10 minutes, and the temperature rises to 83-85°C;

[0025] Immediately use 25-30% sodium hydroxide aqueous solution to adjust the pH to 5.8-6.2. When the temperature is 83-85°C, add 35 parts of the second batch of urea evenly, stir for 10 minut...

Embodiment 2

[0040] 1. Formula composition

[0041] The molar ratio of formaldehyde to urea is F / U=1.82, 590 parts of formaldehyde (concentration 37%), 245 parts of urea (purity 98%), 75 parts of melamine, 1.5 parts of polyvinyl alcohol, 1 part of hexamethylenetetramine, 2 parts of dicyandiamide;

[0042] 2. Glue making process

[0043] Put 590 parts of formaldehyde solution and 1.5 parts of polyvinyl alcohol into the reaction kettle, start the agitator, start heating and heating, stop heating when the temperature rises to 38-40°C, and when the temperature inertia rises to 48°C, use 31-36% hydrochloric acid to adjust the pH value to 1.7-2.0;

[0044] When the temperature rises to 51°C, evenly add 156 parts of the first batch of urea within 7-10 minutes, and the temperature rises to 81-85°C.

[0045] Immediately use 25-30% sodium hydroxide aqueous solution to adjust the pH to 5.5-6.0, and add 38 parts of the second batch of urea evenly when the temperature is 83-85 °C, and add 30 parts o...

Embodiment 3

[0060] 1. Formula composition

[0061] The molar ratio of formaldehyde to urea is F / U=2.107, 1200 parts of formaldehyde (concentration 37%), 430 parts of urea (purity 98%), 115 parts of melamine, 3 parts of polyvinyl alcohol, 2 parts of hexamethylenetetramine, 4 parts of dicyandiamide;

[0062] 2. Glue making process

[0063] Put 1200 parts of formaldehyde solution and 3 parts of polyvinyl alcohol into the reaction kettle, start the agitator, start heating and heating, stop heating when the temperature rises to 37-38 °C, and when the temperature inertia rises to 47 °C, use 30-36% hydrochloric acid to adjust the pH value to 1.7-2.0;

[0064] When the temperature rises to 51°C, evenly add 312 parts of the first batch of urea within 10-12 minutes, and the temperature rises to 83-85°C.

[0065] Immediately use 25-30% sodium hydroxide aqueous solution to adjust the pH to 5.5-6.0, and add 76 parts of the second batch of urea evenly when the temperature is 83-85 °C, and add 40 p...

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Abstract

The invention discloses a modified urea-formaldehyde resin adhesive for a concrete formwork, which is mainly prepared from the following raw materials in parts by weight: 50 to 60 parts of formaldehyde with the mass concentration of 37 percent, 20 to 30 parts of urea with purity of 98 percent, 6 to 8 parts of melamine, 0.1 to 0.2 part of tackifier and 0.2 to 0.3 part of accelerant. The adhesive has an Uron-ring improved structure, so that the waterproofness of the formwork can be improved. The invention also discloses a production method of the adhesive, which comprises three steps of strong acid, weak acid and weak base. The reaction between the formaldehyde and the urea under a strong acid reaction condition can be effectively controlled by controlling temperature, pH value, charging speed, charging time and molar ratio. Meanwhile, two endpoint control indexes which are simple and convenient and are easy to operate are provided, and therefore processing implementing can be controlled conveniently and accurately.

Description

technical field [0001] The invention belongs to the field of modified urea-formaldehyde resin adhesives, in particular to a modified urea-formaldehyde resin adhesive for concrete templates and a production method thereof. Background technique [0002] In recent years, my country has become the world's largest producer of wood-based panels. In 2009, the national output of wood-based panels reached 115.4665 million cubic meters, of which plywood accounted for 44.5124 million cubic meters. Concrete (construction) formwork is the main purpose of plywood. It is mainly used outdoors. It must not only bear load but also withstand the sun exposure and sudden shower without cracking. At the same time, the concrete formwork must be disassembled and reusable for many times. Reduce infrastructure construction costs and wood consumption. In order to detect the bonding strength of concrete formwork, the national standard GB / T 17656-2008 for plywood for concrete formwork adopts the detect...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09J161/30C08G12/38B27D1/04
Inventor 刘幽燕张运明蒋林斌唐爱星
Owner GUANGXI UNIV
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