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 mod

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
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Example Embodiment

[0025] Example 1

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

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

[0028]

[0029] Wherein, the reaction enhancer (ie, crosslinking enhancer) is acrylic acid grafted nano-kenaf fiber whiskers;

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

[0031] A preparation method of the grafted nano-kenaf fiber whisker modified urea-formaldehyde resin adhesive includes the following steps:

[0032] 1) Put 591.2 parts by weight of 37% industrial formaldehyde into the reactor, adjust the pH 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 keep it warm for...

Example Embodiment

[0050] Example 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 molar ratio of formaldehyde to urea is 1:0.98, and each raw material is formulated For comparison, see Table 3 below:

[0052] raw material Moles content,% Weight fraction Remarks formaldehyde7.1237569.8 Response enhancer 10010 Polyvinyl alcohol 1050 Urea7.0499.8430.2 U1=210.8 copies U2=140.5 copies U3=78.9 copies Acid solution (formic acid + ammonium chloride) 30 Right amount 50% each Lye (sodium hydroxide + triethanolamine) 30 Right amount 50% each

[0053] Prepare materials according to the molar ratio of formaldehyde to urea of ​​1:0.98, and the reaction steps include:

[0054] 1) Put 569.8 parts by weight of 37% industrial formaldehyde into the reactor, adjust the pH to 7.0 with lye, add 10 parts by weight of reaction enhancer, heat up to 50°C, add 50 parts by wei...

Example Embodiment

[0068] Experimental 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, and then add 30% flour to make a three-layer 400×400 mm plywood.

[0070] Poplar veneer: moisture content is dried to 6-10%; 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] Prepare plywood according to the following normal process:

[0073] (1) Gluing: double-sided sizing of the core board, the amount of glue is 320-360g / m 2 ;

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

[0075] (3) Preload pressure and time: 40 minutes of preload, 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 GB / T17657-1999 "Experimental method of physical and chemical properties of wood-based panels and decorative wood-...

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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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