Urea-formaldehyde resin adhesive for artificial boards and preparation method thereof

Abstract

The invention relates to a urea-formaldehyde resin adhesive for artificial boards and a preparation method thereof. The urea-formaldehyde resin adhesive is prepared from, by weight, 1351-1650 kg of formaldehyde, 900-1500 kg of urea, 131-400 kg of melamine, 10-60 kg of a high-effective water-proofing agent, 3-4 kg of PVA, 29-30 parts of NaOH and 4-5 kg of formic acid. In the formula, the condensation polymerization synthesis degree between hydroxymethyl melamine and hydroxymethyl urea is high under an acidic condition during preparation, so that quantity of hydrophilic groups in the resin is greatly reduced, and heat resistance and water resistance of the hydrophilic group are improved. The urea-formaldehyde resin adhesive has further reinforced non-melting and non-dissolving three-dimensional structure, so that the adhesive is better in performances.

Description

technical field

[0001] The invention relates to the production field of adhesives, in particular to a urea-formaldehyde resin adhesive for wood-based panels and a preparation process thereof. Background technique

[0002] Formaldehyde, urea, melamine, high-efficiency compounding agent, sodium hydroxide and formic acid are used to prepare urea-formaldehyde resin adhesive for wood-based panels. The ratio of each component is different, which directly affects the acidic conditions of methylol melamine and methylol urea in the preparation process. The degree of polycondensation synthesis under the lower degree, and the degree of polycondensation synthesis determines the content of hydrophilic groups in the resin, the less the hydrophilic groups, the infusible and insoluble body structure of the prepared urea-formaldehyde resin adhesive will be enhanced, and the heat resistance and water resistance will be improved. the better.

[0003] The Chinese invention patent with the pate...

Examples

Embodiment 1

[0018] A preparation process of urea-formaldehyde resin waterproof and boiling-resistant adhesive for wood-based panels, comprising the following steps:

[0019] (1) Weigh the following components respectively: formaldehyde: 1450kg, urea: 1145kg, melamine 131-400kg, high-efficiency waterproofing agent: 35kg, PVA: 3.5kg, sodium hydroxide: 29-30kg and formic acid: 4.5kg, And the weighed urea is divided into four parts to be fed: the first part of urea is 700kg, the second part of urea is 175kg, the third part of urea is 150kg, the fourth part of urea is 120kg, and the formic acid is adjusted into 20% formic acid aqueous solution.

[0020] (2) Add formaldehyde and the first portion of urea to the reaction kettle, open the steam valve to raise the temperature to 40-70°C, add 40-100kg of melamine, then add 3-6kg of sodium hydroxide to adjust the pH value to 7.5-9.0, add After PVA heats up to 85-95°C, close the steam valve and keep warm for 30-70 minutes. In the early stage, urea a...

Embodiment 2

[0030] Weigh each component by weight as follows:

[0031] Formaldehyde: 1351kg, urea: 900kg, melamine 131-400kg, high-efficiency waterproofing agent: 10kg, PVA: 3kg, sodium hydroxide: 29-30kg and formic acid: 4kg, and divide the weighed urea into four parts, the first part of urea For 600kg, the second part of urea 100kg, the third part of urea 100kg, the fourth part of urea 100kg; all the other steps can make the wood-based panel urea-formaldehyde resin adhesive of the present invention equally according to the same process of embodiment one.

Embodiment 3

[0033] Weigh each component by weight as follows:

[0034] Formaldehyde: 1650kg, urea: 1500kg, melamine 131-400kg, high-efficiency waterproofing agent: 60kg, PVA: 4kg, sodium hydroxide: 29-30kg and formic acid 5kg, and the urea weighed is divided into four parts, of which the first urea is 900kg, the second part of urea 250kg, the third part of urea 200kg, the fourth part of urea 150kg; all the other steps can make the wood-based panel urea-formaldehyde resin adhesive of the present invention equally according to the same process of embodiment one.

[0035] Through the ratio of the above components (formaldehyde: 1351-1650kg, urea: 900-1500kg, melamine 131-400kg, high-efficiency waterproofing agent: 10-60kg, PVA: 3-4kg, sodium hydroxide: 29-30kg and formic acid 4 -5kg), the quality indicators of the wood-based panel urea-formaldehyde resin waterproof and boiling-resistant adhesive prepared by the adhesive are as follows:

[0036] Water solubility: 0.61

[0037] Curing time (...

technical field

[0001] The invention relates to the production field of adhesives, in particular to a urea-formaldehyde resin adhesive for wood-based panels and a preparation process thereof. Background technique

[0002] Formaldehyde, urea, melamine, high-efficiency compounding agent, sodium hydroxide and formic acid are used to prepare urea-formaldehyde resin adhesive for wood-based panels. The ratio of each component is different, which directly affects the acidic conditions of methylol melamine and methylol urea in the preparation process. The degree of polycondensation synthesis under the lower degree, and the degree of polycondensation synthesis determines the content of hydrophilic groups in the resin, the less the hydrophilic groups, the infusible and insoluble body structure of the prepared urea-formaldehyde resin adhesive will be enhanced, and the heat resistance and water resistance will be improved. the better.

[0003] The Chinese invention patent with the pate...

Examples

Embodiment 1

[0018] A preparation process of urea-formaldehyde resin waterproof and boiling-resistant adhesive for wood-based panels, comprising the following steps:

[0019] (1) Weigh the following components respectively: formaldehyde: 1450kg, urea: 1145kg, melamine 131-400kg, high-efficiency waterproofing agent: 35kg, PVA: 3.5kg, sodium hydroxide: 29-30kg and formic acid: 4.5kg, And the weighed urea is divided into four parts to be fed: the first part of urea is 700kg, the second part of urea is 175kg, the third part of urea is 150kg, the fourth part of urea is 120kg, and the formic acid is adjusted into 20% formic acid aqueous solution.

[0020] (2) Add formaldehyde and the first portion of urea to the reaction kettle, open the steam valve to raise the temperature to 40-70°C, add 40-100kg of melamine, then add 3-6kg of sodium hydroxide to adjust the pH value to 7.5-9.0, add After PVA heats up to 85-95°C, close the steam valve and keep warm for 30-70 minutes. In the early stage, urea a...

Embodiment 2

[0030] Weigh each component by weight as follows:

[0031] Formaldehyde: 1351kg, urea: 900kg, melamine 131-400kg, high-efficiency waterproofing agent: 10kg, PVA: 3kg, sodium hydroxide: 29-30kg and formic acid: 4kg, and divide the weighed urea into four parts, the first part of urea For 600kg, the second part of urea 100kg, the third part of urea 100kg, the fourth part of urea 100kg; all the other steps can make the wood-based panel urea-formaldehyde resin adhesive of the present invention equally according to the same process of embodiment one.

Embodiment 3

[0033] Weigh each component by weight as follows:

[0034] Formaldehyde: 1650kg, urea: 1500kg, melamine 131-400kg, high-efficiency waterproofing agent: 60kg, PVA: 4kg, sodium hydroxide: 29-30kg and formic acid 5kg, and the urea weighed is divided into four parts, of which the first urea is 900kg, the second part of urea 250kg, the third part of urea 200kg, the fourth part of urea 150kg; all the other steps can make the wood-based panel urea-formaldehyde resin adhesive of the present invention equally according to the same process of embodiment one.

[0035] Through the ratio of the above components (formaldehyde: 1351-1650kg, urea: 900-1500kg, melamine 131-400kg, high-efficiency waterproofing agent: 10-60kg, PVA: 3-4kg, sodium hydroxide: 29-30kg and formic acid 4 -5kg), the quality indicators of the wood-based panel urea-formaldehyde resin waterproof and boiling-resistant adhesive prepared by the adhesive are as follows:

[0036] Water solubility: 0.61

[0037] Curing time (...

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