Melamine-urea-methyl aldehyde copolycondensation resin lumber adhesive and preparation thereof

A wood adhesive and copolycondensation resin technology, applied in the direction of adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve the problems of poor storage stability, limited resin performance, and high manufacturing costs, and achieve storage stability. , the effect of excellent performance

Active Publication Date: 2008-11-12
SOUTHWEST FORESTRY UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] UMF co-condensation resins can only be used in indoor glued products and non-structural fields. It is an urgent market demand to develop high-performance MUF resins and produce glued products used in outdoor and harsh environments, especially the production of wood structure building components. UMF Co-condensation resins cannot meet their performance requirements, while traditional phenolic resins have the defects of slow curing speed and high production cost
Melamine-urea-formaldehyde polycondensation resin (MUF) is considered to be one of the most promising high-performance resins, but there are defects such as poor storage stability and high manufacturing cost in the manufacture and use of MUF. The key to technology
[0007] At present, UMF co-condensation resin usually starts from the initial polymer of urea-formaldehyde resin, that is, urea-formaldehyde resin is synthesized first, and then co-condensation resin is synthesized on this basis. Such a synthetic route hinders the co-condensation between melamine, urea and formaldehyde. And have a negative impact on the stability of the resin
It should be pointed out that under the above synthetic route, with the increase of the amount of melamine, the stability of the resin gradually decreases. Therefore, the synthetic route limits the amount of melamine, so the performance of the resin is also limited.
[0008] Through literature search, there is no public report identical with the present invention

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The adhesive is formed by polycondensation of melamine, urea and formaldehyde, of which:

[0025] a. Take 2.9 moles of formaldehyde, adjust the pH value to 9.0, add 1 mole of urea for the first time and 0.05 moles of melamine for the first time under stirring, and heat up to 90 ° C after 10 minutes of reaction;

[0026] b. After incubating and reacting for 60 minutes at 90°C, adjust the pH value to 7.5, and incubate for 120 minutes;

[0027] c. Adjust the pH value to 8.5, control the temperature at 85°C, add 0.35 moles of melamine for the second time, and keep warm until the water number is 5;

[0028] d. Maintain the pH value at 8.5, lower the system temperature at 55°C, and add 0.2 moles of urea for the second time;

[0029] e. After continuing to react for 50 minutes, cool naturally to obtain a melamine-urea-formaldehyde co-condensation resin wood adhesive.

Embodiment 2

[0031] The adhesive is formed by polycondensation of melamine, urea and formaldehyde, of which:

[0032] a. Take 3.3 moles of formaldehyde, adjust the pH value to 9.2, add 1.04 moles of urea for the first time and 0.06 moles of melamine for the first time under stirring, and heat up to 94 ° C after 20 minutes of reaction;

[0033] b. After incubating and reacting at 94°C for 40 minutes, adjust the pH value to 4.5, and incubate for 60 minutes;

[0034] c. Adjust the pH value to 9.0, control the temperature at 90°C, add 0.40 moles of melamine for the second time, and keep warm until the water number is 2;

[0035] d. Maintain the pH value at 9.0, lower the system temperature at 65°C, and add 0.2 moles of urea for the second time;

[0036] e. After continuing to react for 35 minutes, cool naturally to obtain a melamine-urea-formaldehyde co-condensation resin wood adhesive.

Embodiment 3

[0038] The adhesive is formed by polycondensation of melamine, urea and formaldehyde, of which:

[0039] a. Take 3.3 moles of formaldehyde, adjust the pH value to 9.5, add 1.04 moles of urea for the first time and 0.06 moles of melamine for the first time under stirring, and heat up to 99 ° C after 30 minutes of reaction;

[0040] b. After incubating and reacting at 99°C for 20 minutes, adjust the pH value to 5.5, and incubate for 30 minutes;

[0041] c. Adjust the pH value to 9.5, control the temperature at 95°C, add 0.40 moles of melamine for the second time, and keep warm until the water number is 4;

[0042] d. Maintain the pH value at 9.5, reduce the system temperature to 75°C, and add 0.2 moles of urea for the second time;

[0043] e. After continuing to react for 20 minutes, cool naturally to obtain a melamine-urea-formaldehyde co-condensation resin wood adhesive.

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Abstract

The invention relates to melamine-urea-formaldehyde copolycondensation resin (MUF) wood adhesives and a method for preparing the same, belonging to the wood processing and production technical field. The adhesives are formed by copolycondensation of melamine (M), urea (U) and formaldehydes (F) and are characterized in that: the formaldehydes are added at a time and the urea and the melamine are added for a plurality of times, and the amount of the formaldehydes is over 40 percent of the total amount of the urea and the melamine, wherein, the formaldehydes are added at a time during the initial reaction stage, and urea for the first time and melamine for the first time are added during the initial reaction stage; after the urea for the first time is added, the mole ratio of the formaldehydes and the urea is controlled to be over 2.9; melamine for the second time is added during the intermediate reaction stage; and urea for the second time is added during the late reaction stage. The melamine-urea-formaldehyde copolycondensation resin (MUF) wood adhesives have the advantages of good stability, excellent performance and so on, are used for producing hard boards and particularly high-performance hard boards, laminwood and so on, and also can be used for producing impregnated paper.

Description

Technical field: [0001] The invention relates to a melamine-urea-formaldehyde polycondensation resin (MUF) wood adhesive and a preparation method thereof, belonging to the technical field of wood-based panel production in wood processing. Background technique: [0002] Phenolic resin (PF), urea-formaldehyde resin (UF) and melamine-formaldehyde resin (MF) are the most important adhesives for wood-based panel production, among which phenolic resin is mainly used in the production of structural wood-based panels and outdoor wood-based panels. Although phenolic resin has a series of Advantages, but its curing rate is low, and cost is high at the same time, urea-formaldehyde resin has significant advantages such as fast curing speed and low manufacturing and use cost, but there are defects such as easy hydrolysis and formaldehyde release, while melamine-formaldehyde resin has fast curing speed and good water resistance Performance, but the adhesive layer is brittle and the cost i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09J161/20C08G8/38B27D1/04
Inventor 杜官本雷洪
Owner SOUTHWEST FORESTRY UNIVERSITY
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