Wood plywood phenolic glue

The production of glue has been around for hundreds of years and is mainly used in the leather industry. The main component of tannin is tannin, a natural polyphenolic compound with a large amount of active hydroxyl groups and carboxyl groups, which can replace phenol as a raw material for some industries. In the early 1990s, many research institutes in China carried out research on the use of plant tannins instead of phenol to obtain woodworking adhesives, including larch bark tannins and inkweed tannins.The production of glue has been around for hundreds of years and is mainly used in the leather industry. The main component of tannin is tannin, a natural polyphenolic compound with a large amount of active hydroxyl groups and carboxyl groups, which can replace phenol as a raw material for some industries. In the early 1990s, many research institutes in China carried out research on the use of plant tannins instead of phenol to obtain woodworking adhesives, including larch bark tannins and inkweed tannins.

In recent years, the formulation process has been improved and improved, and the liquid glue is made into powdered glue, thereby avoiding the self-polycondensation reaction during storage, so that the storage period of the adhesive is greatly extended, and packaging and transportation are also convenient. Laboratory studies have shown that this powdered larch tannin phenolic glue is easy to use and has good gluing properties.

2 Main performance indexes of powdered larch tannin phenolic glue

Appearance: Dark brown red powder Solid content: ≥ 90 %
Viscosity: 70 ~ 1 50s (coating - 4 cups 2 5 ° C)
Free phenol: ≤ 0.3% free formaldehyde: ≤ 0.2%
Can be bromide: ≥ 1 2 % water soluble multiple: 2 0
Storage period: 1 year or more pH value: 10.5~1 2

3 Application tests and results

3.1 Application on Pinus masson plywood formwork

3 . 1 . 1 Test conditions The test was carried out at the Jiangle Wood-based Panel Factory in Fujian Province. Specific test pieces:

1 Pinus masson veneer: thickness 2.0 mm, moisture content 8% ~ 10%.
2 Gluing process: Pour 40kg of warm water (water temperature about 50 °C) into the mixing cylinder, add 50kg of powdered larch tannin phenolic glue, stir for 20 minutes (stirring speed 1 50r min), then add 5kg of flour, stir Evenly.
3 Glued blank: The short core plate is coated on both sides with a glue amount of 2 3 0~2 50g m2; immediately after the glue is applied, the number of slab layers is 9 layers.
4 hot pressing: the slab directly enters the hot press without pre-pressing, hot pressing temperature: 1 40 ~ 1 45 ° C, unit pressure: 1.2 MPa, hot pressing time: 18 min.

3 . 1 . 2 Test results

Test batch: Specification 1 0 0 0mm × 2 0 0 0mm × 1 5mm A total of 46 sheets, counting 1.38 m3, a total of 50kg of powdered rubber was consumed. After the hot-pressed burrs were stacked for 25 hours, the edges were sawed and the test samples were randomly taken. The glue strength test is based on the concrete formwork plywood standard (GB9846.8-1 2). The test results are as follows:

The number of valid test pieces: 41, the number of qualified test pieces (gluing strength ≥0.8): 40, the number of unqualified test pieces: 1 Glue strength: Maximum value: 1.84MPa, minimum value: 0.78MPa, average value: 1. 1 6MPa, average wood breaking rate: 53%.