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Preparation method of E0-grade urea-formaldehyde adhesive

A technology of urea-formaldehyde glue and formaldehyde solution, applied in the direction of adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve problems such as affecting production capacity, avoid pollution, increase viscosity, and achieve good bonding performance.

Inactive Publication Date: 2020-11-27
广西诺信化工科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Common urea-formaldehyde resins on the market are graded according to viscosity, and are divided into E0, E1 and E2, etc. The common E0 grade is the best with a viscosity of 0.25-0.4 / (Pa·s). , in order to make the viscosity of urea-formaldehyde glue reach the E0 level, it is necessary to modify the viscosity of urea-formaldehyde resin during the preparation process, but the existing modifiers require higher temperature for modification, and melamine is easy to decompose at high temperature. affect overall productivity

Method used

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  • Preparation method of E0-grade urea-formaldehyde adhesive

Examples

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Effect test

Embodiment 1

[0023] A preparation method of E0 grade urea-formaldehyde glue, comprising the following steps:

[0024] (1) Mixing and heating stage: first use a metering pump to put 37% formaldehyde solution into the reaction kettle, add sodium hydroxide solution to adjust the pH value between 7.0, then start stirring after adding polyvinyl alcohol and melamine, and react under normal pressure Introduce steam into the kettle jacket to raise the temperature to 55° C., and react for 40 minutes. In this step, the ratio of parts by weight of formaldehyde solution, polyvinyl alcohol and melamine is 57.6:1:1;

[0025] (2) Addition stage: add urea to the reaction kettle after mixing and heating up, then raise the temperature of the reaction kettle to 70°C through steam, stop adding steam, and wait for the temperature to rise to 82°C naturally, then cover the outer layer of the reaction kettle to keep warm Set, heat preservation reaction for 30 minutes, add urea and formaldehyde contained in interm...

Embodiment 2

[0032] A preparation method of E0 grade urea-formaldehyde glue, comprising the following steps:

[0033] (1) Mixing and heating stage: first use a metering pump to put 37% formaldehyde solution into the reaction kettle, add sodium hydroxide solution to adjust the pH value between 7.2, then start stirring after adding polyvinyl alcohol and melamine, and react under normal pressure Introduce steam into the kettle jacket to raise the temperature to 58° C., and react for 40 minutes. The ratio of formaldehyde solution, polyvinyl alcohol and melamine in parts by weight is 57.6:1:1 in this step;

[0034] (2) Addition stage: add urea to the reaction kettle after mixing and heating, then raise the temperature of the reaction kettle to 70°C by steam, stop adding steam, and wait for the temperature to rise naturally to 83°C, then cover the outer layer of the reaction kettle to keep warm Set, heat preservation reaction for 30 minutes, add urea and formaldehyde contained in intermediate A ...

Embodiment 3

[0041] A preparation method of E0 grade urea-formaldehyde glue, comprising the following steps:

[0042] (1) Mixing and heating stage: First, use a metering pump to pour 37% formaldehyde solution into the reaction kettle, add sodium hydroxide solution to adjust the pH value between 7.5, and then start stirring after adding polyvinyl alcohol and melamine, and react under normal pressure Pass steam into the still jacket to raise the temperature to 60° C., and react for 40 minutes. In this step, the ratio of formaldehyde solution, polyvinyl alcohol and melamine in parts by weight is 57.6:1:1;

[0043](2) Addition stage: add urea to the reaction kettle after mixing and heating, then raise the temperature of the reaction kettle to 70°C by steam, stop adding steam, wait for it to naturally heat up to 84°C, and keep warm on the outer layer of the reaction kettle Set, heat preservation reaction for 30min, add urea and formaldehyde contained in intermediate A with a molar ratio of ≤1, ...

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Abstract

The invention discloses a preparation method of an E0-grade urea-formaldehyde adhesive. The preparation method comprises a mixing and heating stage, an addition stage, a polycondensation reaction stage, an European water removing stage and a cooling stage, according to the invention, active hydroxymethyl is contained in hydroxymethyl urea generated by condensation polymerization, and further condensation is carried out to generate a polymer, so that the molecular weight of the obtained urea-formaldehyde glue polymer is about 700, while the molecular weight of the traditional urea-formaldehydeglue is about 120, the molecular structure with larger molecular weight is more stable, and the gluing performance is better; according to the invention, oxidized starch is added as a modifier in thecondensation polymerization process; carboxyl groups at other positions in the oxidized starch can react with hydroxyl groups in the urea-formaldehyde resin; the urea-formaldehyde resin forms a tightcross-linked body structure, intermolecular winding is compact, intermolecular gaps become small, the viscosity of the urea-formaldehyde resin is increased, meanwhile, the oxidized starch can react with formaldehyde which does not react completely, and the content of free formaldehyde in the urea-formaldehyde resin is reduced.

Description

Technical field [0001] The present invention relates to the field of urea-formaldehyde resin adhesive, specifically a preparation method of E0 grade urea-formaldehyde adhesive. Background technique [0002] Urea-formaldehyde resin is also called urea-formaldehyde resin. The English abbreviation UF is the polycondensation of urea and formaldehyde under the action of a catalyst (alkaline or acidic catalyst) to form an initial urea-formaldehyde resin, and then under the action of a curing agent or additive, it forms an insoluble and infusible final thermosetting resin. Cured urea-formaldehyde resin is lighter in color than phenolic resin, translucent, resistant to weak acids and weak alkali, has good insulation properties, excellent wear resistance, and is cheap. It is the most commonly used variety among adhesives. [0003] Common urea-formaldehyde resins on the market are classified according to their viscosity and are divided into E0, E1 and E2. The common E0 grade is the o...

Claims

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Application Information

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IPC IPC(8): C09J161/32C08G12/44C08G12/38
CPCC08G12/38C08G12/44C09J161/32
Inventor 冯大强
Owner 广西诺信化工科技有限公司
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