Preparation And The Properties Of Slow Rebound Polyurethane Viscoelastic Foam

Slow rebound polyurethane foam,because of its good shape memory characteristics,strong energy absorption and shock absorption and other properties,has been widely used in many fields.Such as the sealing and shock absorption for components and parts in computers,mobile phones and other electronic products;the cushion material for shoe and clothing;the cushion material for medical equipment;the buffer sealing materials for automotive interior and other fields.However,because of its own serious closed-cell structure(foam perforation rate is less than 50%),the compressive strength of foam suffers a sharp rise under the high compression rate,which limits the use of slow rebound polyurethane foam.In order to solve this problem,foreign scholars have developed a slow rebound opening agent,resulting in promoting the foam openings.However,the bubble can easily collapse,and the pore size is large and inhomogeneous when the opening rate is too high.Therefore,how to effectively control the foam opening rate and pore size to ensure that the foam material has a very good slow resilience and maintains a low strength under high-magnification compression is the key issue in the preparation of slow rebound polyurethane foams.In this paper,based on the shortcomings of the high rate of obturator for the slow recovery of polyurethane foam and the instability caused by the addition of the opening agent,the structure of the foam is controlled by water,composite catalyst,foam stabilizer and the opening agent at the same time and finally a half-open slow rebound polyurethane foam is prepared with a uniform distribution of the pore,the pore diameter of 100 to 200?m,and the porosity of 50% to 70%.It can act as the role of shock absorption after its application in the automotive interior and electronic products.And also it looks forward to solving the current domestic vacancy in ultra-thin mobile phone problems for slow rebound polyurethane foam.Firstly,the effects of water,composite catalyst and foam stabilizer on the structure and properties of slow rebound polyurethane foam were discussed.The optimum conditions for preparing slow rebound polyurethane foam were determined:the total number of polyols was 100 parts,the amount of water used was 3 parts,the triethylene diamine(A33)was 0.35 part,the dibutyltin dilaurate(T12)was 0.06 parts,and the foam stabilizer was 1 part.Under this condition,the slow rebound polyurethane foam in this paper is synthesized without collapse,shrinkage and other undesirable phenomena,compared with the traditional commercial slow rebound polyurethane foam.Secondly,the viscoelasticity of the slow rebound polyurethane foam was studied.The theoretical glass transition temperature(Tg)of the slow rebound polyurethane foam was calculated by Fox equation.The experimental results show that the actual Tg is consistent with the theoretical calculation.And the effects of different molecular weight polyol on the damping performance and foam recovery time of slow rebound polyurethane foam were discussed.The results show that when the amount the polyether polyol L2000: polyether polyol 330N: polymer polyol 3628 is 50:40:10,the foam with good damping performance,short recovery time(10 seconds)and wide damping temperature range is obtained.Finally,the effects of water,polyether polyol L-2000,polymer polyol 3628,pore-opening agent Y-1900,and isocyanate index on 40% compressive strength(CLD40%)were studied.The results showed that when the polymer polyol 3628 was added in an amount of 10 parts,the water was 3 parts,the isocyanate index was 0.7,the polyether polyol L-2000 was 50 parts and the opening agent was 0.25 parts.A comprehensive performance of the slow rebound polyurethane foam(polyurethane foam tan? value of 0.4,CLD40% compression strength of 1.3Kpa and foam recovery time of 10 seconds)is obtained.