Do You Want to Know What Happen to Your EPS Raw Material
what is the cause of this phenomenon?
Is there a problem with the raw materials?
Or other reasons?
What is the essence of this?
Entering the autumn and winter, the temperature is low, and the temperature is relatively
sensitive to the EPS production process. If the board is broken, the first thing to look at is
foaming. Once the foaming is not good, and the quality of the board is not good. Generally
speaking, we talk about the influencing factors and more about the temperature.
The temperature of the pellets just pre-event from the pre- expander is generally between
40 and 50 ° C, and some of the steam permeates into the interior of the pellet during the
pre-expansion process. Because the temperature difference between the foam particles
and the environment is large, the residual foaming agent and steam inside the foam
particles are quickly condensed into a liquid, and the liquid foaming agent is dissolved
into the polystyrene foam particles, and the internal pressure of the foam particles is
rapidly lowered. The inside presents a negative pressure (or partial vacuum). At this time,
the foam particles appear soft and are easily deformed. It is impossible to make an EPS
foam product, which must be matured after a while; after ripening, on the one hand, it
is dried, on the other hand, the air is made. It penetrates the inside of the bubble to
eliminate the negative pressure, balances the pressure inside and outside the bubble,
makes the bubble round and elastic, ensures the expansion of the bubble and the fusion
between the beads during the molding, thereby improving the quality of the EPS product.
Understand the mechanism of pre-fabrication and maturation, if the winter pre-fabrication
and maturation workshops have poor heat preservation effect, the temperature is low, the
thermal expansion and contraction, the easy particle collection is severe, and the bubble
structure is destroyed, so it cannot rebound when matured. At this time, the lighter weight
plate is used, and the plate is prone to shrinkage, cracking, and the board becomes heavier.
Generally, the curing temperature has the best value. Generally, the curing temperature is
18~22°C, and the air penetrates the inside of the bubble. The pentane inside the bubble
does not diffuse outward. The temperature exceeds 22 °C, and the air infiltration speed
increases and accelerates. At the same time, the rate of out- ward diffusion of pentane is
also accelerated; on the contrary, if the temperature is lower than 20 ° C, the air infiltration
rate is also significantly reduced, and the curing time is lengthened. For this reason, the
general curing temperature is controlled between 20 and 25 ° C. If the main production
of light board customers, the temperature of the curing workshop can be appropriately
increased to about 28 or so.
If the temperature of the curing chamber is too low, in some winters, some foam factory
insulation facilities do not do well, and the air leaks on all sides. Basic and outdoor
temperature is similar, winter temperature is low, basically 0, so the foaming agent inside
the bubble is liquid, can not be vaporized and expanded, resulting in shrinkage of the
bubble, poorly finished hand feeling.