Views: 152 Author: Site Editor Publish Time: 2020-09-02 Origin: Site
Table of Contents:
The polystyrene resin, nucleating agent, combustion aid, etc. enter the first-stage plastic extruder through the feeder.
After being fully plasticized in the extruder, the foaming agent is injected (freon, gas, and environmentally friendly carbon dioxide foaming agents are also commonly used). The foaming agent is fully mixed with other raw materials in the second-stage extruder and extruded through the die after cooling.
After the die is extruded, the pressure is released rapidly, and the foaming agent wrapped in plastic expands rapidly to form closed cells. Under the action of the cells, the polystyrene plastic forms a foamed plate with honeycomb-shaped closed cells.
Then the plate is shaped to the required thickness and width through the shaping tractor and then cut into shape.
Auxiliary equipment also includes an extruded board surface roughening machine, recycling granulator, edge forming machine, slotting machine, automatic packaging machine, etc.
Polystyrene resin, foaming agent, nucleating agent, flame retardant, color masterbatch, foam stabilizer, etc.
Over time, the blowing agent in the extruded board will be replaced by air.
Foaming agent dissolution→bubble nucleation→bubble growth and stabilization→curing and molding.
Increase the speed and density of nucleation as much as possible. The nucleation density is a key factor in determining the blasthole density.
The formation of bubbles in a single homogeneous phase is called homogeneous nucleation. The formation of bubbles under the catalysis of the interface of fine particles is called heterogeneous nucleation.
Cooling rate, gas precipitation from the melt, decomposition, and gasification of the blowing agent.
The general extruded board production line 24H can produce 200+m³ of extruded boards.
Flame retardants are divided into the additive type and reactive type. Mainly include inorganic, halogen, phosphorus, and nitrogen. The most used is hexabromododecane (HBCD).
The addition amount of B2 grade extruded board is 5%-6%, and the addition amount of B1 grade is 10%+.
Yes, but because the price is too high, there is basically no enterprise use. HBCD has been banned in developed countries such as Europe and the United States.
HCFC-22, HCFC-142b, carbon dioxide, butane, ethanol, dimethyl ether, liquefied petroleum gas, etc.
It can be divided into physical blowing agents and chemical blowing agents, as well as organic blowing agents and inorganic blowing agents.
Commonly used are talc, calcium carbonate, citric acid, metal powder, etc., as well as gaseous nucleating agents such as nitrogen and carbon dioxide. Nucleating agents affect the structure and density of the foam.
The new extruded board without any color masterbatch is white. The extruded boards on the market are white, blue, red, yellow, green, etc., among which white is the highest end.
There are usually constant volume type quantitative feeding system and weight type quantitative feeding system.
The foaming agent is delivered from the storage tank to the metering pump under a fixed pressure.
The viscosity and elasticity of the melt, gas permeability, vapor pressure, solubility, and decomposition temperature of the blowing agent.
Quantitative: The constant and balanced input of raw materials ensures that the machine head has a constant amount of material extrusion.
Constant temperature: The viscosity of the melt, whether the foaming is sufficient, and the molding are all related to the temperature.
Constant pressure: reasonable system pressure comes from a balanced quantitative and suitable temperature range.
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