Grafted nano ambary fiber crystal whisker modified urea formaldehyde resin adhesive and preparation method thereof

A technology of kenaf fiber and urea-formaldehyde resin, applied in the direction of adhesives, aldehyde/ketone condensation polymer adhesives, adhesive types, etc., can solve the problems of poor water resistance, reduced bonding strength, increased product cost, etc., to reduce The amount of formaldehyde released, the effect of increasing the content of the crystalline region, and reducing the viscosity of the resin

Active Publication Date: 2014-12-10
BEIJING FORESTRY UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For example: 1) Although the use of low molar ratio modified urea-formaldehyde resin adhesives can effectively reduce the formaldehyde emission of wood-based panel products, the bonding strength of the products is often reduced, which cannot meet the requirements of use; and it can lead to prolonged curing time and reduced production efficiency; 2) Adding formaldehyde scavenger to urea-formaldehyde resin adhesives for wood-based panels can effectively reduce the release of free formaldehyde from wood-based panels, but it often reduces the bonding strength of wood-based panels at the same time; at the same time, the price of general formaldehyde scavenger is often much higher than that of urea-formaldehyde resin adhesives. Adding improves product cost and reduces product competitiveness; 3) Carry out post-processing to wood-based panels, as the invention patent application with publication number CN1526528 discloses a method for preparing E1 / EO grade environment-friendly wood-based panels using ammonia vacuum method. Manufacturing process; the utility model patent with publication number CN2394770 discloses a treatment device for reducing formaldehyde emission from wood-based panels. These post-processing methods not only make the manufacturing process of wood-based panels complicated, but also require huge investment in post-processing equipment and significantly increase production costs. ; 4) The use of other environmentally friendly adhesives, such as isocyanate adhesives, has led to a substantial increase in the production cost of wood-based panels and increased difficulty in the production process, which is difficult for enterprises and users to accept; the use of ordinary protein adhesives to prepare wood-based panels has low bonding strength and poor water resistance , easy to mold, poor sizing performance, easy to open glue for wood-based panels
In summary, although the above measures can effectively reduce the release of free formaldehyde from wood-based panels, they cannot completely solve the problem of formaldehyde release, or cannot be popularized due to reasons such as high production costs.

Method used

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  • Grafted nano ambary fiber crystal whisker modified urea formaldehyde resin adhesive and preparation method thereof
  • Grafted nano ambary fiber crystal whisker modified urea formaldehyde resin adhesive and preparation method thereof
  • Grafted nano ambary fiber crystal whisker modified urea formaldehyde resin adhesive and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] A grafted nano kenaf fiber whisker modified urea-formaldehyde resin adhesive, prepared from formaldehyde, urea, polyvinyl alcohol and a reaction enhancer, wherein the molar ratio of formaldehyde to urea is 1.07: 1, each raw material See Table 1 below:

[0027] Table 1 The molar ratio of formaldehyde to urea is 1.07︰1 Raw material ratio of urea-formaldehyde resin

[0028]

[0029] Wherein, the reaction enhancer (i.e. cross-linking enhancer) is acrylic acid grafted nano kenaf fiber whiskers;

[0030] The solid content of the reaction enhancer is 100%.

[0031] A kind of preparation method of above-mentioned grafted nanometer kenaf fiber whisker modified urea-formaldehyde resin adhesive, comprises the following steps:

[0032] 1) Put 591.2 parts by weight of 37% industrial formaldehyde into the reaction kettle, adjust the pH value to 7.0 with lye, add 5 parts by weight of reaction enhancer, heat up to 50°C, add 30 parts by weight of polyvinyl alcohol solution, and kee...

Embodiment 2

[0051] A grafted nano kenaf fiber whisker modified urea-formaldehyde resin adhesive is prepared from formaldehyde, urea, polyvinyl alcohol and a reaction enhancer, wherein the mol ratio of the formaldehyde to urea is 1:0.98, each raw material See Table 3 below:

[0052] raw material moles content,% weight fraction Remark formaldehyde 7.12 37 569.8 response enhancer 100 10 polyvinyl alcohol 10 50 urea 7.04 99.8 430.2 U1=210.8 copies U2=140.5 parts U3=78.9 parts Acid solution (formic acid + ammonium chloride) 30 Appropriate amount 50% each Lye (sodium hydroxide + triethanolamine) 30 Appropriate amount 50% each

[0053] It is 1:0.98 to prepare raw materials by formaldehyde and urea molar ratio, and reaction step comprises:

[0054] 1) Put 569.8 parts by weight of 37% industrial formaldehyde into the reaction kettle, adjust the pH value to 7.0 with lye, ...

experiment example

[0069] Add 0.5% ammonium chloride and 0.3% citric acid to the urea-formaldehyde resins of Example 1-2 and Comparative Example 1-2 respectively, and then add 30% flour to make three-layer plywood of 400×400mm.

[0070] Poplar veneer: dry to 6-10% moisture content; thickness 1.5mm;

[0071] The veneer adhesive used the product of Example 1-2 of the present invention and the product of Comparative Example 1-2.

[0072] Plywood is prepared according to the normal process as follows:

[0073] (1) Glue sizing: Glue is applied on both sides of the core board, and the amount of glue applied is 320-360g / m 2 ;

[0074] (2) Aging method and time: closed aging, 20-30 minutes;

[0075] (3) Pre-compression pressure and time: pre-compression for 40 minutes, pressure 0.9MPa;

[0076] (4) Hot pressing pressure: 1.0MPa, hot pressing temperature is 120-130oC, hot pressing time is high pressure 90s / mm.

[0077] According to the test method of GB / T17657-1999 "Physical and Chemical Properties ...

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Abstract

The invention discloses a grafted nano ambary fiber crystal whisker modified urea formaldehyde resin adhesive and a preparation method thereof. The grafted nano ambary fiber crystal whisker modified urea formaldehyde resin adhesive is prepared from formaldehyde, urea, polyvinyl alcohol and a reaction enhancer, wherein the mole ratio of the formaldehyde to the urea is (1.1-0.95):1, and the addition amount of the polyvinyl alcohol is 0.1-0.8% of the total weight. The addition amount of the reaction enhancer is 0.1-3.0% of the total weight. The preparation method comprises the following steps: adding the reaction enhancer, adding the first batch of urea according to a mole ratio of (2.0-2.2):1, adding the second batch of urea according to the mole ratio of (1.4-1.2):1, and finally, adding the third batch of urea according to the mole ratio of (0.95-1.1):1. By using the formaldehyde and urea in a low mole ratio as the raw materials, the self-made acrylic acid grafted nano ambary fiber crystal whisker is added to increase the molecule branching degree and molecular weight of the resin, so that the low-mole-ratio urea formaldehyde resin has the advantages of low formaldehyde content, high adhesion strength and low cost.

Description

technical field [0001] The invention relates to an adhesive, in particular to a grafted nano-kenaf fiber whisker-modified urea-formaldehyde resin adhesive and a preparation method thereof, belonging to the field of adhesives. Background technique [0002] With the improvement of people's living standards and the continuous and stable development of construction, decoration, packaging and other industries, the output of wood-based panels in my country has grown rapidly. The total output of wood-based panels, plywood, furniture, and wood flooring has ranked first in the world for many years in a row. In 2013, the total output of wood-based panels in my country was 272 million m 3 , accounting for about 50% of the world's total production. Average production of 9m per ton of adhesive 3 According to the calculation of wood-based panels, the consumption of wood adhesives in my country in 2013 was about 30 million tons (solid content 50%), among which urea-formaldehyde resin an...

Claims

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Application Information

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IPC IPC(8): C09J161/24C09J11/08C08G12/12C08F251/02
Inventor 李晓娜高强李建章张世锋周文瑞张伟陈惠
Owner BEIJING FORESTRY UNIVERSITY
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