New glue technologies for plywood production

Wood-based panels are mainly divided into plywood, block board, particle board, medium-density fiberboard, etc. The plywood is made of veneer sheets and glue through heating and lamination. Generally, horizontal and firm cross lamination are used for lamination to increase the strength. Glue in the production process of plywood is one of the main raw materials. In the traditional production of E2 grade products, formaldehyde and urea are mainly used as the main raw materials. However, the production process takes a long time and requires a large amount of materials and consumption of energy.

The new solution of making glues is to reduce the amount of urea and formaldehyde in the glue, it also reduce the consumption of raw materials, gas steam and electricity,but the glue bonding keep same with before. In order to achieve the above object, the present invention adopts the following technical scheme: A preparation method of glue for plywood, the production steps of making glue for this type technology are as follows

1) first time feeding: add 0.1 parts of polyethylene, 60 parts of formaldehyde, 24 parts of urea, 9 parts of ammonia water in sequence, stir and heat to 90 degrees Celsius, keep warm for half an hour, adjust the pH value to 4.8-5.1 after the heat preservation is completed, and the glue is dripping Bowl speed reaches about 5-6 seconds;

2) For the second feeding: add 6 parts of urea and 2 parts of melamine, heat and stir for half an hour, then add an appropriate amount of 40% alkaline water stops the reaction and cools down to 80 degrees Celsius to ensure a pH value of 6-6.5;

3) For the third feeding:add 4 parts of urea and continue stirring to cool down to 70 degrees Celsius to increase the viscosity of the glue;

4) For the fourth feeding:add a certain amount of urea and continue stirring to cool down for half an hour before gelling.

5) detect: sampling part glue;

6) Storage, ready for use: Store the qualified glue in the glue storage tank for use.

In the described process, stirring is not stopped from feeding to gelling process, so that material evenly reacts.

Benefits of the present invention: shortened operating time, reduced raw material consumption, steam consumption and power consumption, also greatly reduced the pollution of environment simultaneously, increased the productivity of enterprise.

A preparation method of glue for plywood, the production steps are as follows:

1) for the first feeding:add polyethylene 2kg, formaldehyde 1200kg, urea 480kg, ammonia water 180kg in turn, stir and heat to 90°C, keep warm for half an hour, adjust the PH value to 5 after the heat preservation is completed, at this time, the speed of the glue dripping bowl reaches about 6 seconds;

2) For the second feeding,:add 120kg of urea and 2kg of melamine, heat and stir for half an hour, then add an appropriate amount of 40% alkaline water stops the reaction and cools down to 80°C to ensure the pH value is 6.5;

3) For the third feeding:add 80kg of urea and continue stirring to cool down to 70°C to increase the viscosity of the glue;

4) For the fourth feeding:add 20kg of urea and continue stirring to cool down for half an hour before gelling;

5) Testing: sampling part of the glue;

6) Storage, ready for use: store the qualified glue in the glue storage tank for use.

Above an embodiment of the present invention has been described in detail, but described content is only preferred embodiment of the present invention, can not be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the application scope of the present invention shall still belong to the scope covered by the patent of the present invention.