For the production of polyurethane sponges, the maturation process of new sponges is a high incidence of fire accidents. Because the internal temperature of the large sponge is high and the heat dissipation lasts for a long time, the time to reach the highest internal temperature is usually 30-60 minutes, and it will start to decline slowly in 3-4 hours or longer. During this period of time, all the new foams have left the production line and entered the mature storage section which is easily overlooked. If there is no good monitoring measures, it will easily cause a fire.
Therefore, sponge manufacturers should strictly pay attention to the maturation and storage procedures of sponges, strictly control the measurement accuracy of each component, and reduce measurement errors. In the production of continuous lumpy sponges, attention should be paid to adjusting the material discharge speed of the mixing head and the running speed of the conveyor belt to make them coordinated. It is necessary to avoid the influx of uninitiated materials due to slow conveyor belt speed or excessive discharge volume. The underflow phenomenon at the bottom of the material prevents the material from normally starting to collapse and the collapsed material is not easy to produce local "gas species", causing local heat accumulation and increasing the risk of scorching.
Adjust the formula to control the water consumption not to exceed 4.5 parts. If necessary, use a low-boiling liquid compound auxiliary foaming agent to replace the partial water. In order to prevent the spontaneous combustion of the sponge, the sponge manufacturer shall mature and store the newly produced sponge and the stacking time shall not exceed 3 layers, the spacing must be greater than 1 meter, and it is best to store them separately. When the sponge is found to smoke or spontaneously ignite, use water spray or use a fire extinguisher to extinguish the fire. Do not move the sponge or open doors and windows at will so as not to increase the air flow and expand the fire. For sponges that are likely to produce high temperatures, a large piece of sponge should be cut horizontally (such as a thickness of 20CM) as needed to facilitate the heat dissipation of the sponge. The maturation storage section should be equipped with full-time staff to strengthen monitoring, such as measuring the internal temperature of the sponge every 15 minutes for at least 12 hours or even longer and then storing normally. The highest temperature rise safety point for low-density sponges is 160°C which cannot exceed 170°C.
The newly produced sponge should be prevented from being compressed and deformed by external force. The reason is that when the sponge is not fully matured, the sponge network and sponge structure will be affected by external force compression. At the same time, it is also to avoid heat accumulation due to compression and increase the risk of spontaneous combustion of the sponge. Especially in the most sensitive stage of the sponge rising response, any manipulation errors and vibrations, such as the jerking motion caused by the excessively tight conveyor belt chain, excessively wrinkled separator paper and the bumps of the conveyor belt, will cause the compression of the mature sponge. Resulting in scorching.
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