Study On Preparation And Propertie Of Wide Temperature Range And Hight Performance Microporous Rubber Pad

The high-speed railway damping pad commonly using on the market include polyurethane foam backing plate,EVA foam pad,EPDM foam pad,etc.Those minimum operating temperature is not more than-30℃,which can not meet the using requirements of high-speed railway shock absorption in cold area.In order to solve this problem,a foam rubber material resistant to-50℃ has been studied.Firstly,selecting of low temperature resistant rubber for foam rubber pad.The rubber BR/NR,BR/SBR,SBR-NS612,BR-1261,BR-1250H,SBR-15 was studied.It is found that none of them can meet the requirements of low temperature resistant to-50℃.It was found that SBR-10 was synthesized without crystallization and the glass transition temperature was-56℃,which meet the requirements of low temperature.Therefore,entrusting company to synthesize SBR-10 latex.The flocculating process of latex was studied.It was found that the flocculating yield of high molecular flocculant CA was as high as 86%,and the flocculation cost was as low as 1300 yuan per ton of dry rubber,which was suitable for industrial production.Secondly,material design and performance study of foam backing plate.The effects of reinforcing system,plasticizing system,vulcanizing system and foaming agent on the comprehensive properties of vulcanized rubber and foamed rubber were studied.The reinforcing system is 30 phr silica and 3 phr Si-69.The plasticizing system is paraffin oil and white oil paste,each plasticizer is 5 phr.The vulcanizing system is 1.5 phr sulfur and 1.5 phr DPBMH.OBSH was selected as foaming agent,the best decomposition temperature was 148℃,and the best dosage was 3 phr.Thirdly,study on preparation technology of foam backing plate.Foaming rubber was prepared by two-stage mold foaming process.The synergistic properties of vulcanization and foaming were studied.The results show that the vulcanization reaction of rubber and the decomposition reaction of foaming agent simultaneous in the range of 125℃-135℃.When the amount of foaming agent is constant,the pre-vulcanization temperature is at 125℃,the cells diameter increase and the cells density decrease with the increase of vulcanization time,so the foaming process is faster than the vulcanization process.When the pre-vulcanization temperature is above 130℃,the cells diameter and cells density decrease with the increase of vulcanization time.The time interval between the initiation of foaming and vulcanization becomes shorter,and the limiting effect of vulcanization on foaming increases.The pre-vulcanization temperature is 125℃ and the time is 13 min,the second step curing temperature is 150℃ and the curing time is 20 minutes.