Production of redispersible polymer powder is mainly divided into two steps: The first step is the production of the polymer emulsion through emulsion polymerization; the second step is spray- drying the mixture prepared by the polymer emulsion to obtain the polymer powder.
Drying process: The polymer emulsions prepared are delivered into a spray- drier by a screw pump for drying , the inlet temperature of dryer generally to be 100 ~ 200ºC, at the outlet generally to be 60 ~ 80 ºC. Since spray- drying occurs within a few seconds , then the distribution of the particles are "frozen" , and the protective colloid as the spacer particles play a role in isolation , thereby preventing the polymer particles from irreversible coalescence. In order to prevent redispersible powder from “caking” during transportation and storage, the anti-caking agent must be added in the spray drying process or later.
Basic parameters of redispersible emulsion powder spray drying equipment:
1.Materials: polymer emulsion
2.Dried powder production: 100 kg/h ~700kg/h
3.Solid content: 5%~55%
4.Heating source: gas furnace, diesel combustion furnace, superheated steam, biological particles combustion furnace, etc. (To be changed according to customers)
5.Way of atomizing: high Speed centrifugal atomizer
6.Material recovery: two-level bag filter is adopted; the recovery rate is 99.8% which is in line with the national emission standards.
7.Receiving: centralized receiving is adopted. After powder discharging from the bottom of tower body to the bag dust remover, powders are sent to the receiving bag by an wind conveying system, and then through the sieve vibrating to a stock bin, finally removing iron to automatic packing machine for receiving.
8.Material adding way: quantitative addition is done by two automatic feeding machines in two tops, and the feeding machine has weighing system that accurately charging any amount can be carried out.
9.Electrical control: Using PLC program control. (automatic control for inlet air temperature and outlet air temperature, alarm for oil temperature and oil pressure of atomizer, display for negative pressure inside the tower) or full computer DCS control.
For urea resin adhesive, its bonding strength is high, temperature resistance; water resistance and corrosion resistance are good. In addition, because the resin itself is transparent or milky white, the made-up shaving board and fiberboard with medium density show beautiful colors, and the made-up plywood would not produce pollution, so use in the wood products do not affect the appearance. Urea resin powder is made of liquid resin through spray drying, it is an one-component adhesive powder, with such excellent performances as water resistant, mildew proof, anti-yellowing, strong adhesion, anti-aging, capable cold or hot pressing, not easy to deformation, convenient use, long period of storage etc.. Suitable for bending wood, skinning, assembling, thin wood veneer, edging, particleboard, bonded between medium density fiberboards, which is an ideal adhesive for assembling furniture, wood gluing etc.
Drying process: The resin emulsions prepared are delivered into a high-speed centrifugal atomizer by a screw pump, and are atomized into a large number of small droplets with uniform size. Contacting with the hot air in the drying tower, water is quickly evaporated, and then water vapor and powders enter into the cloth bag dust remover. Water vapor passes through a filter bag into the induced draft fan for emptying, the dry powders which fall down at the bottom of the bag dust remover due to pressure drop, are concentrated into the small bags for material receiving through the rotary valve and the air conveying pipes. and then through the sieve vibrating to a stock bin, finally removing iron to automatic packing machine for receiving. In order to prevent redispersible powder from “caking” during transportation and storage, the anti-caking agent must be added with a screw feeder in the spray drying process.
Basic Parameters of the urea-formaldehyde resin spray drying equipment:
1.Materials: polymer emulsion
2.Dried powder production: 100 kg/h ~700kg/h
3.Solid content: 5%~55%
4.Heating source: gas furnace, diesel combustion furnace, superheated steam, biological particles combustion furnace, etc. (To be changed according to customers)
5.Way of atomizing: high Speed centrifugal atomizer
6.Material recovery: two-level bag filter is adopted; the recovery rate is 99.8% which is in line with the national emission standards.
7.Receiving: centralized receiving is adopted. After powder discharging from the bottom of tower body to the bag dust remover, powders are sent to the receiving bag by an wind conveying system, and then through the sieve vibrating to a stock bin, finally removing iron to automatic packing machine for receiving.
8.Material adding way: quantitative addition is done by two automatic feeding machines in two tops, and the feeding machine has weighing system that accurately charging any amount can be carried out.
9.Electrical control: Using PLC program control. (automatic control for inlet air temperature and outlet air temperature, alarm for oil temperature and oil pressure of atomizer, display for negative pressure inside the tower) or full computer DCS control.