Study On Film Forming Process And Blending Of Carboxyl Nitrile Latex

The outbreak of COVID-19 pandemic has led to the rapid development of disposable latex examination gloves,and the price of the raw material carboxy nitrile rubber(XNBRL)has risen rapidly.In order to further improve the performance of gloves and reduce the cost,people have strengthened the basic research and modification research of XNBRL.Carboxylated nitrile rubber is a non-self-reinforcing polar rubber.Its latex film has poor mechanical properties,low tensile strength,poor tear resistance and softness.The research on reinforcement and combined modification of XNBRL has practical value and theoretical significance.In this paper,the effect of the ratio of sulfur(S)/ accelerator Diethyl dithio zinc carbamate(ZDEC)/ zinc oxide(Zn O)vulcanization system on the tensile properties and cross-linking degree of carboxyl nitrile rubber film was studied by orthogonal design test method,and the effect of the combined ratio of zinc methacrylate(ZDMAC)/ titanium dioxide on the reinforcement of carboxyl nitrile rubber film was studied.The results show that in the S / ZDEC / Zn O vulcanization system,the most influential factor on the tensile strength of XNBRL film is the amount of sulfur,and zinc oxide has the function of helping crosslinking of XNBRL.When the ratio of the S: ZDEC:Zn O vulcanization system is 1.25 : 1 : 3,the comprehensive performance of XNBRL film is the best;ZDMAC has excellent reinforcing effect on XNBRL.When the combination ratio of titanium dioxide : ZDMAC : antioxidant 445 is 1.5: 1: 1.5,the comprehensive performance of the adhesive film is the best,and the tensile strength can reach more than 30 MPa.Based on the reinforcement of XNBRL latex,the process conditions of coagulant impregnation film formation of carboxyl nitrile latex coagulant were studied.The effects of impregnation time,coagulant concentration,latex concentration and latex temperature on the latex film formation process were investigated.The results show that the temperature of latex compounding has the greatest influence on the colloidal properties of latex;The latex temperature is 25 ?,the impregnation time is 20 s,and the concentration of coagulant is 25 %.When the latex concentration is 20 %,the film thickness uniformity,smoothness and tensile properties of the film obtained by coagulant impregnation method are the best.The compatibility and mechanical properties of the blend film of XNBRL and carboxyl styrene butadiene latex(XSBRL)were studied by differential scanning calorimetry(DSC),fourier infrared spectroscopy(FTIR)and scanning electron microscope(SEM)and other advanced equipment.The research results show that XNBRL / XSBRL has good compatibility between the two phases,the phase interface is blurred,red,and the combined film has only one glass transition peak;When the blending ratio(dry ratio)of XNBRL / XSBRL is 90 / 10,the blending latex film has the best comprehensive performance;ZDMAC has obvious reinforcing effect on XNBRL / XSBRL blend film.When the dosage is 1.5 phr,the tensile strength can reach more than 40 MPa.The compatibility of XNBRL / natural latex(NRL)film was studied,and the compatibility and mechanical properties of XNBRL / NRL film were improved by latex pre-vulcanization,combined use of accelerator CZ / M and addition of epoxidized natural latex(ENRL).The results show that the compatibility of XNBRL / NRL blend system have poor compatibility,and there were two obvious glass transition peaks,and the interface between phase regions is relatively clear;The compatibility of XNBRL /NRL blend system,the combined use of accelerator CZ / M and the method of adding compatibilizer ENRL-50 can improve the compatibility of XNBRL / NRL combined system to a certain extent.When the blending ratio(dry ratio)of XNBRL / NRL / ENRL is 90 / 5 / 2,the tensile strength of the adhesive film can reach 33 MPa.