Research On The Control Method For Quality Consistency Of Whole Latex

Natural rubber is obtained from Hevea brasiliensis.It contains about 5%non-rubber substances.It is due to presence of a small amount of non-rubber substances in natural rubber and the storage hardening of natural rubber resulting in greater quality fluctuation of natural rubber.For a long time,the quality consistency problem of domestic natural rubber is not resolved,so that the rubber of domestic high-end products always rely on imports.Such as the rubber of military equipment and tire,etc.The article is based on the actual problems of natural rubber processing industry in china.The new type and high-performance natural latex preservatives that is developed by research group in early stage is used to fresh latex maturation,so that the phenomenon of storage hardening is weakened and the quality consistency is improved of whole latex.The study shows that the HY/NH₃ of compound preservative?0.07%HY and 0.3%NH₃compounded by latex weight?is used to preserve fresh latex for 1-5 days.With the time of latex maturation extending,the impurity content,ash content and volatile matter content are decreased gradually,but the plastic retention rate PRI is increased gradually.The plastic initial value P₀,mooney viscosity,molecular weight and cross-linking density of whole latex all show an tendency that increase first and then decrease with time of latex maturation extending and the extremum appears on the third days of latex maturation.With time of latex maturation extending,The nitrogen content,fatty acid content and gel content of raw rubber increase gradually,while the content of acetone solution decrease gradually and the content of phosphorus do not change significantly.With time of latex maturation extending,the vulcanization rate of compound rubber decrease gradually and vulcanization time increase slightly.The tensile strength before aging and tearing strength of vulcanizate increase first and then decrease with time of latex maturation extending.The results of storage experiments shows that the plastic initial value P₀ and mooney viscosity of whole latex prepared by fresh latex matured 3 days varies within range of±5after storage for six months and conforms with the requirements of quality consistency of natural rubber.The variation of nitrogen content,phosphorus content,acetone dissolved content,fatty acid content,gel content of raw rubber,vulcanization time of compounded rubber,crosslink density and physical and mechanical properties of vulcanizate are relatively small.The mechanism analysis shows that the non-rubber substances of raw rubber is prepared of fresh latex that matures different time do not change significantly.The plastic initial value P₀ and mooney viscosity have small changes during storage.It indicates that the maturation treatment of fresh latex promotes cross-linking of rubber molecules and reduces cross-linking reactions between rubber molecules during storage and weakenes phenomenon of storage hardening and improves quality consistency of whole latex.