A kind of preparation method of whole process alkaline synthetic urea-formaldehyde resin wood adhesive

A technology for synthesizing urea-formaldehyde resins and wood adhesives, which is applied in the fields of adhesives, adhesive types, aldehyde/ketone condensation polymer adhesives, etc., and can solve problems that have not been reported and cannot be synthesized with urea-formaldehyde resins.

Active Publication Date: 2022-03-29
GUIZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This patent provides a method for the whole alkaline synthesis of melamine urea-formaldehyde resin, but it cannot be used for the synthesis of urea-formaldehyde resin
At present, there is no report on the research on the whole process of alkaline synthesis of urea-formaldehyde (UF) resin.

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  • A kind of preparation method of whole process alkaline synthetic urea-formaldehyde resin wood adhesive

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Embodiment 1

[0026] A kind of preparation method of whole course alkaline synthetic urea-formaldehyde resin wood adhesive:

[0027] (1) Add the first metered formaldehyde solution into the reaction kettle, adjust the pH value to 7.5-9.0; add the first urea under stirring, control the molar ratio of formaldehyde to urea at 1.0, and then gradually raise the temperature of the reactant to 90-95°C; the stirring speed is 1500r / min;

[0028] (2) After heat preservation and reaction at 90-95°C for 30 minutes, cool down to 80-85°C, adjust the pH value to 9.0-10.0 with a compound base, add the second formaldehyde solution, and control the molar ratio of formaldehyde to urea is 1.8;

[0029] (3) Add a batch of formaldehyde at 80-85°C for every 30 minutes of heat preservation reaction until the molar ratio of formaldehyde to urea is 2.0, adjust the pH value to 10.0-11.0, then raise the temperature to 90-95°C, keep warm React for 90 minutes;

[0030] (4) Cool down to 70-80°C, adjust the pH value to...

Embodiment 2

[0033] A kind of preparation method of whole course alkaline synthetic urea-formaldehyde resin wood adhesive:

[0034] (1) Add the first metered formaldehyde solution into the reaction kettle, adjust the pH value to 7.5-9.0; add the first urea under stirring, control the molar ratio of formaldehyde to urea at 1.2, and then gradually raise the temperature of the reactant to 90-95°C; where the stirring speed is 2000r / min;

[0035] (2) After heat preservation and reaction at 90-95°C for 60 minutes, lower the temperature to 80-85°C, adjust the pH value to 9.0-10.0 with a compound base, add the second formaldehyde solution, and control the molar ratio of formaldehyde to urea in 1.8;

[0036] (3) At 80-85°C, add a batch of formaldehyde after every 30 minutes of heat preservation reaction until the molar ratio of formaldehyde to urea is 2.1, adjust the pH value to 10.0-11.0, then raise the temperature to 90-95°C, keep warm React for 90-180 minutes;

[0037] (4) Cool down to 70-80°...

Embodiment 3

[0040] A kind of preparation method of whole course alkaline synthetic urea-formaldehyde resin wood adhesive:

[0041] (1) Add the first metered formaldehyde solution into the reaction kettle, adjust the pH value to 7.5-9.0; add the first urea under stirring, control the molar ratio of formaldehyde to urea at 1.4, and then gradually raise the temperature of the reactant to 90-95°C; the stirring speed is 3000r / min;

[0042](2) After heat preservation and reaction at 90-95°C for 90 minutes, cool down to 80-85°C, adjust the pH value to 9.0-10.0 with a compound base, add the second formaldehyde solution, and control the molar ratio of formaldehyde to urea in 2.0;

[0043] (3) At 80-85°C, add a batch of formaldehyde after every 30 minutes of heat preservation reaction until the molar ratio of formaldehyde to urea is 2.2, adjust the pH value to 10.0-11.0, then raise the temperature to 90-95°C, keep warm React for 180 minutes;

[0044] (4) Cool down to 70-80°C, adjust the pH value...

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Abstract

The invention belongs to the technical field of wood-based panel production, in particular to a method for preparing a whole-process alkaline synthetic urea-formaldehyde resin wood adhesive. The present invention uses a composite base catalyst in the synthesis process, and the whole synthesis process is carried out under alkaline conditions, and formaldehyde and urea are added in multiple times, specifically: first, the formaldehyde solution is added to the reactor in batches to react with urea for the first time , and then add the second urea reaction in batches to the reactor. The urea-formaldehyde resin wood adhesive synthesized by the present invention has similar structural properties to the urea-formaldehyde resin synthesized by the alkali-acid-alkali process, and solves the problem of the acid reaction of the primary polymer generated in the alkaline reaction stage in the synthesis process of the alkali-acid-alkali process. Phase will be partially rearranged into methylene bridges, reducing the content of ether bonds in urea-formaldehyde resins. The invention refutes the industry consensus that all-alkali cannot synthesize urea-formaldehyde resin, and fills in the blank of all-alkali synthesis of urea-formaldehyde resin.

Description

technical field [0001] The invention belongs to the technical field of wood-based panel production, in particular to a method for preparing a whole-process alkaline synthetic urea-formaldehyde resin wood adhesive. Background technique [0002] Urea-formaldehyde resin is the most important basic adhesive in the production of wood-based panels, which has significant advantages such as fast curing speed and low manufacturing cost. [0003] At present, the synthesis process of urea-formaldehyde resin is mainly a three-stage synthesis process of weak base-weak acid-weak base. The formaldehyde-urea molar ratio (F / U) of the process in the first alkaline reaction stage is generally controlled above 2 / 1, and the final molar ratio is reduced by adding the second urea in the final alkaline reaction stage, while achieving the reduction of free The purpose of formaldehyde content. The traditional theory holds that methylolation reaction mainly occurs in the initial alkaline reaction st...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08G12/12C09J161/24
CPCC08G12/12C09J161/24
Inventor 吴志刚梁坚坤李涛洪杜官本张本刚余丽萍曹明
Owner GUIZHOU UNIV
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