Slow rebound sponge is also called inert sponge, memory sponge, low rebound sponge, slow rebound sponge and zero pressure sensing sponge. Because of the special polyether, the sponge produced has a certain memory function and is widely used in pillows, mattresses and packaging. According to different processes, it can be divided into free foaming sponge series and MDI molding series.
"Slow rebound" is a term specially designed for slow rebound sponge. It means mechanical property: when the slow rebound sponge is compressed and deformed by an external force, it will not rebound immediately, but will be delayed for a few seconds to recover slowly. Therefore, when we press the slow rebound sponge with our hands, we can see our fingerprints, as if the slow rebound sponge can remember the shape of the thing pressing it, so the name "slow rebound sponge" comes from this.
Main components of slow rebound composite polyether
Mixture of at least two polyether polyols
Generally speaking, polyethers are selected by matching macromolecules with low molecules. At present, polyethers with low molecular weight, multi-function and high hydroxyl value include K-1030, V-2070, SR-308, GLR-2000, etc; High molecular weight, highly active polyether polyol (molecular weight 4500-6500); Polymer polyol (molecular weight about 6000); Low functional polyether polyol (molecular weight 1000-4000); Mix two or more together.
Crosslinking agent (usually low molecular alcohol or amine compound)
It is usually some low molecular weight alcohols or amine compounds with bifunctional or greater functions, such as 1,4-butanediol, propylene glycol, dipropylene glycol, diethylene glycol, glycerin, diethanolamine, triethanolamine, etc. Crosslinking agent is mainly used to adjust the proportion of soft segment and hard segment in the molecular structure of the product, so as to improve the slow rebound property of the product.
Catalyst, mostly composed of polyamine catalyst
Polyether used for slow rebound is more active than general polyether, and gel reaction in the reaction system is relatively fast, so tertiary amine catalyst with strong catalytic effect on foaming reaction is selected, and organotin catalyst is generally not used
Foaming agent
At present, chemical foaming agent water is mainly used. Sometimes, physical foaming agent HCFC-141b can be added to reduce product density and improve skin appearance and touch. 141b should be included in the scope of prohibited use, and those who are still using it should look for alternatives in a timely manner.
foam stabilizer and open cell silicone oil
Generally, foam stabilizer with low activity and hydrolysis resistance is selected. At present, in terms of slow rebound silicone oil, Maitu has developed a new type of slow rebound silicone oil with a certain opening.
When selecting polyether, it is often impossible to find a suitable high activity polyether in the market, and only ordinary high activity polyether can be selected. In this case, it is generally necessary to add a certain amount of pore opening agent to make up for the deficiencies in the formula.
