Cyanurotriamide modified urea resin and prepn. process

A melamine, urea-formaldehyde resin technology, applied in the direction of aldehyde/ketone condensation polymer adhesives, adhesive types, adhesives, etc. The effect of boiling water, low cost and simple manufacturing process

Inactive Publication Date: 2006-09-20
EVERFIRST WISEFUND TECH BEIJING +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the melamine urea-formaldehyde resin adhesive has the disadvantages of high formaldehyde emission, poor boiling water resistance, and high production cost.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Concrete reaction steps are as follows:

[0028] 1) Add 37% industrial formaldehyde into the reaction kettle, and adjust the pH value to 3.2-3.4 with formic acid;

[0029] 2) Heat to 50°C to activate formaldehyde for 20 minutes, then add the first batch of urea U127.7 parts by weight, and react at 50°C for 20 minutes;

[0030] 3) Use sodium hydroxide to adjust the pH=7.2-7.8, and add 14.1 parts by weight of the second batch of urea U2;

[0031] 4) Heat up to 90°C within 30-40 minutes and keep warm for 60 minutes;

[0032] 5) Use formic acid to adjust the pH value to 4.2-4.8, react to viscosity: 25°C, apply -4 cups for 22-26 seconds;

[0033] 6) Adjust the pH value to 7.0-7.5 with sodium hydroxide, add 10.7 parts by weight of the third urea U3, add melamine in an amount of 10% of the total amount of urea, and react at 90°C for 20 minutes;

[0034] 7) Cool down to 70°C, add the fourth batch of remaining urea U4, and react for 30 minutes;

[0035] 8) Add industr...

experiment example 1

[0062] Nine-layer plywood specimens 1 and 2 were produced using the melamine-modified urea-formaldehyde resin adhesive obtained by the method of Example 1 of the present invention and the urea-formaldehyde resin adhesive obtained by the method of Comparative Example 1, respectively. Among them, 10% flour and 0.5% ammonium chloride by weight of melamine modified urea-formaldehyde resin are added when coating; the veneer is 10-year-old poplar veneer; the hot pressing process is: pressure 1.0-1.5MPa, temperature: 105-115 ℃; time: 40s / mm.

[0063] Measure the formaldehyde emission of test pieces 1 and 2 with the dryer method, and measure the boiling water resistance bonding strength of test pieces 1 and 2 according to the provisions of GB / T17657-1999 "Physical and Chemical Properties of Wood-based Panels and Decorated Wood-based Panels". The release amount and bonding strength are shown in Table 1.

[0064] Specimen

[0065] As seen from Table 1, utilize the melamine m...

experiment example 2

[0067] Nine-layer plywood specimen 3 was produced by using common urea-formaldehyde resin (molar ratio 1:1.3, solid content 56%) through the same plywood process as above.

[0068] The phenolic resin used in the factory (alkaline water-soluble phenolic resin, the molar ratio is 1: 2.1, and the solid content is 42%) is used to produce the nine-layer plywood specimen 4 by hot pressing; wherein, 10% flour of the resin weight is added when the glue is applied ; The veneer is 10-year-old poplar veneer; the hot pressing process is: pressure 1.5-1.8MPa, temperature: 125-135°C; time: 70s / mm.

[0069] The test pieces 1, 2, 3 and 4 were used as cement formwork respectively, and the actual use effect is shown in Table 2:

[0070] Specimen

[0071] Practical application experiments show that when the multi-layer plywood produced by the melamine-modified urea-formaldehyde resin adhesive of the present invention is used as a cement formwork, the number of times of use can be grea...

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Abstract

This invention provides a method for manufacturing melamine-modified urea-formaldehyde resin adhesive used on wood cement templates. The method adopts formaldehyde and urea at a molar ratio of 1.2-1.4 as the raw materials, and urea is added into formaldehyde in four times. Before the first time of urea addition, formaldehyde is activated at 50 minus or plus 5 deg.C for 15-25 min. in the third time of urea addition, melamine 3-20 wt. % of total urea is also added. After the fourth time of urea addition, ammonia solution is added for post treatment so that the content of free formaldehyde in the modified urea-formaldehyde resin adhesive is below 0.2 wt. %. at the same time the boiling water-resistance of the urea-formaldehyde resin adhesive can be improved. This invention can be used as a substitute for expensive phenol-formaldehyde resin adhesive; therefore the cost is reduced while the performance of wood cement templates can be guaranteed.

Description

technical field [0001] The invention relates to a modified urea-formaldehyde resin and a preparation method thereof, in particular to a melamine-modified urea-formaldehyde resin for wood cement formwork and a preparation method thereof. Background technique [0002] With the rapid development of my country's economy, urban and rural buildings are developing rapidly, and the demand for cement formwork is increasing rapidly. Wood cement formwork has been widely used due to its low price. Because phenolic resin adhesives have good water resistance and weather resistance, phenolic resin adhesives are often used in the manufacture of multi-layer plywood for wood cement formwork. However, due to the high price of phenol, the price of phenolic resin adhesives is also high, and the price of glued products is relatively high. In order to reduce the manufacturing cost of wood-cement formwork, many factories began to use cheap urea-formaldehyde resin adhesives. However, the water-re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09J161/28C09J161/14
Inventor 李建章周文瑞倪潇潇蒋伟张德荣陈欣母军金小娟赵永虎
Owner EVERFIRST WISEFUND TECH BEIJING
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