A two-component adhesive and its application in wood-based panels

An adhesive, two-component technology, applied in the direction of adhesives, layered products, adhesive types, etc., can solve the decline of adhesive bonding performance, the reduction of water resistance and bonding strength of adhesives, and the increase of moisture absorption of products. issues of sex

Active Publication Date: 2022-04-15
SOUTHWEST FORESTRY UNIVERSITY
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  • Abstract
  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

Reducing the molar ratio of formaldehyde to urea can greatly reduce the release of formaldehyde; however, reducing the molar ratio of formaldehyde to urea will affect the performance of the adhesive, causing the adhesive to produce a higher degree of bonding defects, and the water resistance and adhesion of the adhesive. Reduced strength
Added scavengers (sodium bisulfite, sodium metabisulfite, sodium sulfite, sodium sulfamate, ammonium sulfamate, aniline salts, ammonium bisulfite, or ammonium sulfite) can bind free formaldehyde or the formaldehyde released during the curing of the adhesive, thereby reducing the release of formaldehyde; however, the adhesive's bonding performance can also be reduced by adding a scavenger
Treating the surface to be glued with a solution containing ammonium salt before applying the adhesive can also effectively reduce the release of formaldehyde in the product. The ammonium salt on the surface to be glued will react with free formaldehyde to form non-volatile substances, reducing formaldehyde release; however, this method increases the moisture absorption of the product

Method used

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  • A two-component adhesive and its application in wood-based panels

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preparation example Construction

[0031] In the present invention, the preparation method of the two-component adhesive described in the above technical solution preferably includes the following steps:

[0032] Degrading after mixing the tannin and the degrading agent, mixing the obtained degraded tannin and the cross-linking agent to perform a cross-linking reaction to obtain component 2;

[0033] Mix components 1 and 2 before using the two-component adhesive to obtain a two-component adhesive.

[0034] In the present invention, the tannin is mixed with a degrading agent for degradation, and the obtained degraded tannin is mixed with a crosslinking agent for crosslinking reaction to obtain component 2. In the present invention, water is preferably added to the mixing of tannin and degradation agent. In the present invention, the mass ratio of the water and tannin is preferably (25-60):(15-60), more preferably (25-40):(16-20), in an embodiment of the present invention , the mass ratio of water to tannin is ...

Embodiment 1

[0059] Preparation of phenolic resin:

[0060] After heating up 95g (1.0mol) phenol to 80°C, mix it with a sodium hydroxide solution with a mass concentration of 10%, and adjust the pH of the phenol to 10.5; The heating rate was raised to 90°C, and the addition reaction was carried out for 60 minutes;

[0061] Cool the addition reaction product to 60°C and mix it with 0.3mol formaldehyde, raise the temperature to 90°C at a heating rate of 1°C / min, carry out polycondensation reaction for 30 minutes, then cool down to room temperature; dehydrate the product cooled to room temperature under negative pressure , to obtain a phenolic resin with a solid content of 60%.

[0062] To prepare a two-component adhesive:

[0063] The phenolic resin that 300g above-mentioned method is made is directly as component 1;

[0064] After mixing 100g of tannin, 186mL of water, 5g of sodium bisulfite and 3g of sodium sulfite, it was degraded at 120°C for 10h; the degraded product was cooled to ro...

Embodiment 2

[0071] Preparation of urea-formaldehyde resin:

[0072] 86g of formaldehyde solution with a mass concentration of 37% was heated up to 50°C and mixed with a 10% sodium hydroxide solution to adjust the pH value to 8.5, and the adjusted pH value of the formaldehyde solution was mixed with 30g of urea and 3g of melamine and then heated up Addition reaction at 90°C for 45 minutes; mix the product after the addition reaction with formic acid solution with a mass concentration of 10% to adjust the pH value to 4.8, and polycondense the solution with a pH value of 4.8 at 90°C for 30 minutes; Mix with 20g urea and carry out the second-step polycondensation reaction at 80°C for 30min, the product of the second-step polycondensation reaction is cooled to 30°C, and the pH of the second-step polycondensation reaction product is lowered by a sodium hydroxide solution with a mass concentration of 10%. The value was adjusted to 8.5 to obtain a urea-formaldehyde resin with a solid content of 6...

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Abstract

The invention belongs to the technical field of adhesives, and in particular relates to a two-component adhesive and its application in artificial boards. The two-component adhesive provided by the present invention includes independently packaged component 1 and component 2, wherein the component 1 includes formaldehyde-based resin; the component 2 is degraded tannin modified by a crosslinking agent, so The degraded tannin is prepared by degrading the tannin through a degrading agent; the degraded tannin modified by the crosslinking agent is obtained by modifying the degraded tannin by the crosslinking agent; the mass ratio of the tannin and the crosslinking agent is (100 ~80):(15~40); the mass ratio of the component 1 and component 2 is 1:(0.01~0.5). The degraded tannin reduces the steric hindrance of the tannin and increases the reactive sites of the tannin; during the curing process, the degraded tannin modified by the cross-linking agent polymerizes with the formaldehyde-based resin, which improves the performance of the two-component adhesive. Excellent cohesiveness, reducing the decomposition of formaldehyde-based resins makes the two-component adhesive have lower formaldehyde emission.

Description

technical field [0001] The invention belongs to the technical field of adhesives, and in particular relates to a two-component adhesive and its application in artificial boards. Background technique [0002] Formaldehyde-based resin has high bonding strength, water resistance, heat resistance, abrasion resistance and chemical stability, and its price is relatively low, so it is widely used as an adhesive for wood-based panels. However, this type of adhesive will continue to release toxic gas formaldehyde during use. Through research and analysis, it is known that the way of releasing formaldehyde from wood-based panels produced by formaldehyde-based resin adhesives is mainly the following two aspects: 1. The formaldehyde-based resin adhesive itself contains free formaldehyde, that is, unreacted formaldehyde, and Free formaldehyde will be gradually released during and after curing if it is not effectively removed; 2. Formaldehyde-based resins will decompose and release forma...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09J161/14C09J161/32C08G8/28C08G12/40B32B7/12B32B21/13B32B21/14
CPCC09J161/14C09J161/32C08G8/28C08G12/40B32B7/12B32B21/13B32B21/14
Inventor 田珩雷洪徐高翔梁坚坤曹龙
Owner SOUTHWEST FORESTRY UNIVERSITY
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