The invention discloses among a kind of production the carboxylic acrylonitrile butadiene rubber latex preparation method, particularly reaction process residual acrylonitrile monemer in the continuous adding of active higher polymerization single polymerization monomer and the product and deviate from the process modification of method.
If you want to learn more, please visit our website nbr latex manufacturers.
Compare with natural rubber latex, carboxylic acrylonitrile butadiene rubber latex has its special advantages because introduced carboxyl (COOH) and itrile group (CN), so on performances such as oil-proofness, film-forming properties and tensile strength, be enhanced with the dipped goods of carboxylic acrylonitrile butadiene rubber latex manufacturing.At present, the production method of carboxylic acrylonitrile butadiene rubber latex mainly adopts emulsion polymerization in the world, all adopts this method to produce comprising the company of countries and regions such as Taiwan south Supreme Being, Japanese auspicious father-in-law (Zeon) company, German Baeyer (Bayer) company, the U.S..The monomer of producing carboxylic acrylonitrile butadiene rubber latex also comprises unsaturated carboxylic acid (as unsaturated monoprotic acid, unsaturated dibasic acid etc.) except divinyl, vinyl cyanide, other modified monomers (as unsaturated carboxylic acid fat etc.) can also be arranged.Emulsification system generally adopts negatively charged ion and non-ionic composite emulsifying system, the emulsification system that the potassium oleate that adopts as the auspicious father-in-law of Japan, ten alkylsulphonic acid potassium, Soxylat A 25-7 etc. come to this.It is steadily inviolent that this composite emulsifying system has reaction process, and latex is advantage such as easy breakdown of emulsion film forming when being used to flood.Initiator system has the low temperature system of dicumyl peroxide-reductive agent, and the high temperature initiator system that adopts persulphate is also arranged.Feed way once the intermittent reaction that feeds intake of property, also have and add monomeric semicontinuous mode in batches, the mode of production of continuous charging is also arranged.The latex residual monomer remove general employing physics method, as vacuum flashing gas method, vacuum flashing nitrogen extraction method, the also degas method of using with physics method and chemical method.Because of the difference of production method, the latex physical index of each manufacturer also just has nothing in common with each other, but these carboxylic acrylonitrile butadiene rubber latexs generally satisfy the service requirements of downstream user substantially.But exist the disposable adding of monomer sudden and violent poly-shortcoming and the uneven shortcoming of quality product easily take place.
Three, summary of the invention
The objective of the invention is to invent a kind of carboxylic acrylonitrile butadiene rubber latex preparation method who contains the low residue acrylonitrile monemer.The higher monomeric continuous adding of reactive behavior has overcome these monomers and disposable the adding fully sudden and violent poly-shortcoming has taken place easily, production process more steadily and safety like this, simultaneously, also overcome the uneven shortcoming of quality product that the disposable adding of these monomers is produced; The present invention adopts two step degassing methods when latex outgases, and the use of degassing tower efficiently can reduce the wherein content of residual monomer more, is being to have reduced in the finished product latex residual monomer to the harm of human body and environment so just.
Technical scheme of the present invention realizes in the following manner:
(1) carboxylic acrylonitrile butadiene rubber latex adopts the intermittent type emulsion polymerization, and wherein active higher monomer adds with certain speed continuously in reaction beginning back, and the joining day remains in 6-12 hour the scope continuously; Adopt persulphate free radical initiator system simultaneously; Reaction product adopts degassing still and two step of degassing tower degassing method, and especially through after the degassing tower degassing, the content of residual monomer vinyl cyanide is reduced to below the 200ppm in the finished product latex.
(2) reaction desired raw material and proportioning weight percent: deionized water 90-140, emulsifying agent 2.2-3.6 molecular weight regulator 0.5-1.5, pH regulator agent 0.2-0.5, persulphate radical initiator 0.3-1.1, the divinylic monomer 52-68 that disposable then adding reactive behavior is lower, the stirring that starts polymeric kettle makes mixing of materials wherein even, add continuously by the good monomer of following mixed with volume pump, wherein: vinyl cyanide 30-45, unsaturated carboxylic acid 0.5-8, esters of unsaturated carboxylic acids 0.5-7.5.
(3) production process: by described in (1) and (2), be to add deionized water, emulsifying agent, molecular weight regulator and other auxiliary agents under the situation of vacuum at poly-and still, disposable then adding divinylic monomer adds initiator at last.Start the whipping appts of polymeric kettle, be warming up to 40-50 &#;, reaction pressure then continues the active higher mix monomer that adding has mixed with volume pump in reactor when 0.3-0.5Mpa, be vinyl cyanide, unsaturated carboxylic acid and unsaturated carboxylic acid fat, these monomeric continuous joining days are in 6-12 hour scope.Reacted again 2-4 hour, when reaction conversion ratio reaches 99% when above, stopped reaction, processing then outgases.
(4) two-step approach degasification process: directly import degassing still after carboxylic acrylonitrile butadiene rubber latex comes out and carry out the flash liberation first time from polymeric kettle, this process can be deviate from unreacted volatile monomer divinyl completely basically, can not be removed human body and the deleterious acrylonitrile monemer of environment but major part is unreacted.Therefore, the present invention will be from degassing still be pressed into through the latex of the once degassing and carries out in the degassing tower outgasing second time, and the content of residual monomer vinyl cyanide is reduced to 200ppm with the next finished product latex that obtains in latex.
The big content that has reduced residual monomer vinyl cyanide in the finished product latex of the present invention, and owing in reaction process, adopted the continuous active higher monomer methods that adds, thereby whole production technology is operated steadily among the safe state, avoided sudden and violent poly-and dash the generation of accidents such as material.In addition, owing to the milky white of dipped goods color, tensile strength height, the elongation of the latex manufacturing that makes with the present invention are long.
If you are looking for more details, kindly visit carpet backing latex.
Nitrile butadiene rubber (NBR) is used for manufacturing of industrial and automotive rubber products, for example, such as synthetic latex.
NBR is produced in an emulsion polymerization system.
The emulsion process yields a polymer latex, which is coagulated using various materials (e.g. calcium chloride and aluminum sulfate) to form crumb rubber, which is dried and compressed into bales.
By varying temperatures NBR producers manufacture hot and cold polymers. Specialty NBR polymers are obtained by adjusting ratios of Acrylonitrile (ACN) and butadiene (BD), or adding a third monomer (e.g. divinyl benzene and methacrylic acid).
Vaisala Polaris&#; Process Refractometer serves to accurately and reliably determine the degree and the end-point of the polymerization reaction. The information is based on the conversion rate from monomer to polymer. This is determined by the relationship between conversion and the solids content (%) of the components involved.
Learn more about the nitrile butadiene rubber production from the application note.
Download the application note in PDF by filling the form.
Go back to all Chemicals & Allied Products applications
Image
For more SBR latex for paperinformation, please contact us. We will provide professional answers.