At the initial of March, Manager Qian and Manager Zhou attended the New International Expo Center in Shanghai for 4 days. The New International Expo Centerhere is huge and there are so many enterprises and companies. They also met the people who are in the same indurstry and exchanged the cards with each other. What's more, they recommended and introduced our products to the clients. At the same time, they learned a lot from the various products of sponges.      Welcome to visit our factory any time!

The typical characteristic of slow rebound sponges is that when external forces are applied and withdrawn, the deformation process and recovery trajectory are not nearly instantaneous and synchronous response as common sponges. In particular, when reducing, it starts from the outer edge of the stress core point, gradually recovers from the outside, and finally recovers from the stress core point. According to this characteristic of slow rebound sponge, many cushioning products, cushion materials and crafts have been developed. This property of the slow rebound sponge can evenly distribute the pressure exerted on it by irregularly shaped objects, hence the name zero pressure sponge. At the same time, the weak rebound force can maintain the external objects pressed on the sponge to form the geometric shape, which is also the nickname of memory sponge. Formation mechanism of slow rebound sponge As we all know, sponge is made of polyether polyols and isocyanate as the main material, and add the necessary additives. Under normal circumstances, the use of relatively large molecular weight polyether polyols (such as molecular weight 3000 and above 3000) and polymer polyols (molecular weight 60000 and above 6000) and isocyanate reaction, the preparation is a fast rebound sponge, known as ordinary sponge in the industry. In the preparation of slow recovery sponges, high molecular weight polyether polyols/polymer polyols are al always used in combination with low molecular weight polyether polyols (such as molecular weight 700 and 550). In general, we mix polyethers with molecular weight 3000 or above and polyethers with molecular weight 550 or 700 and react with isocyanate to prepare slow recovery sponges. After the reaction of polyether with isocyanate, chain segments of different molecular weight will be formed. The substance produced by the reaction of high molecular weight polyether with isocyanate is called soft segment, and the substance produced by the reaction of low molecular weight polyether with isocyanate is called hard segment. These segments are held together by chemical and physical bonds, which both intertwine, pile up, and cause slight phase separation due to steric effects. As we all know, high molecular weight polyether has low hydroxyl value and low crosslinking density in reaction with isocyanate, so the soft segment has large intramolecular and intermolecular activity space, easy deformation and recovery, that is to say, the soft segment activity is high. However, low molecular weight polyether has high hydroxyl value, high crosslinking density with isocyanate reaction, small intramolecular and intermolecular activity space, and difficult deformation and recovery, that is, low hard segment activity. The above properties of the soft and hard segments, combined with the slight phase separation within the polymer, cause the slow rebound sponge to show asynchronous deformation and recovery of the soft and hard segments during the process of applying and withdrawing external forces. The reason is that soft section deformation and recovery speed is fast, hard section deformation and recovery speed is slow. This is how a slow rebound sponge is formed.

Polyurethane rigid foam with isocyanate and polyether as the main raw materials, under the action of foaming agent, catalyst, flame retardant and other additives, through special equipment mixed, through high pressure spraying site foaming polymer. There are two kinds of polyurethane foam: soft foam and hard foam. The instructions for the use of polyurethane foam, do not understand the hurry to see. a) Remove dirt and grease from the construction surface, and wet the parts to be filled with a little water. b) Use in the temperature range of 5℃-40℃, if construction in cold season, it is recommended to preheat the tank in an environment of 30℃. c) Shake vigorously for more than 1 minute before use. d) Remove the cover, screw on the special construction gun, invert the tank, slowly press the gun handle, the discharge can be normal construction. The tank is in an inverted state during construction. e) After construction, use cleaning agent to remove the residue on the nozzle and valve to avoid solidification and blockage. f) Surface drying in 20-30 minutes, forming an elastic filling structure within 24 hours. g) The molding filler can be cut, polished and sprayed, this product is not UV resistant, it is recommended to further paint.

Clear formation mechanism of slow rebound sponge, can be based on customer needs, design a reasonable formula. For example, the customer requires the sponge rebound speed to be fast, appropriate to reduce the amount of slow rebound polyether, increase the amount of ordinary polyether; The customer requires that the sponge hardness should be high. It can be satisfied by increasing the amount of slow rebound polyether, replacing part of ordinary polyether with white oil, and improving the TDI index. The problem that slow rebound sponge is easy to obturator can also be solved according to the formation mechanism of slow rebound sponge. Generally, the higher the sponge density, the easier to obturator; The higher the TDI index, the easier it is to obturate foramen. In the production of high-density slow rebound sponges, polyether with molecular weight of 550 and hydroxyl value of 306 is ly used. At this time, the crosslinking density increases, chain segment winding and packing are tight, the degree of phase separation is light, and hard segment is the dominant factor, to high obturator rate. Similarly, at a high TDI index, the cross-linking density increases, the hard segment becomes more concentrated, and the obturator tendency increases. The problem can be solved by increasing the amount of opening agent.