| After China’s offshore oil production exceeded the annual output of 50 million tons in 2010,the demand for a special offshore oil transmission hose that depends on imports has increased.Because of the use environment,this hose needs to have 6 major functions: oil resistance,blast resistance,negative pressure resistance,seawater resistance,floatable and leak alarm.Blast resistance is a very critical property,and most similar products use steel wire or polyester fiber to achieve this function.Oil spills will seriously pollute the marine environment,so companies have extremely high requirements for the safety of the hoses.In this topic,aramid fiber is used as the pressure-resistant layer of the hose。Rubber materials properties and structure related to the hose are studied in order to provide a reference for the actual development of the hose.(1)Through research,it is found that the adhesion between the aramid cord and the rubber being used in the factory is too low to meet the requirements.In order to develop a new rubber used for adhering aramid cords,the adhesive properties of aramid cords and rubber used for adhering steel cords were studied.The experimental conclusion is that the H pull-out force is high and meets the requirements,but peel strength of the rubber and cords is low.After optimizing the dosage of sulfur,the physical properties of the rubber and the H pull-out force both meet the requirements,but the peel strength is far from enough.The adhesives RA-65,resorcinol and cobalt neocatenate in rubber used for adhering steel cords were added to other rubbers to explore the effect of adhesives on the adhesive properties of interface between aramid cords and rubber.The results show that the adhesive RA-65 and resorcinol can improve the adhesive properties,especially the peel strength,while the cobalt neodecanoate has little effect.The optimal dosage of adhesive RS and RA-65 was explored.When the dosage of adhesive was 5phr of RA-65 and 3phr of RS,the H pull-out force was 184.5 N/piece,and the peel strength was 15.9 N/piece,which all meet the properties requirements。The monomer resorcinol is not directly used in the formula,which is helpful for industrial production.(2)A transition rubber for adhering the inner rubber layer and the aramid cord pressure-resistant layer was prepared by selecting the rubber type and adding the RA system adhesive,which solved the problem of poor adhesion properties due to the large difference in polarity between the two.The adhesive strength is 8.65 k N/m,which meets the requirements.By introducing the superspeed accelerator BZ and optimizing the amount of sulfur and accelerator,the seawater-resistant CR(chloroprene rubber)composite material for the cover was prepared.The preparation process is in line with the actual production process(vulcanization condition: 97 ℃ × 8 h).Its seawater resistance is good.After the material was immersed in artificial seawater at room temperature for 180 days,the tensile strength only decreased by 5.2%,the elongation at break decreased by 14.9%,and the weight change rate was less than 3%.By introducing RA series adhesive and optimizing the amount of carbon black from the original 40 phr of N990 and 25 phr of N550 to 35 phr of N550 on the basis of the covering rubber,a transition rubber for adhering flange steel and cover layer was prepared,and cooperated with Chemlok to solve the problem of adhesion between cover and flange.Their bond strength is 13.43 k N/m,which meets the requirements.(3)Through the analysis of similar hoses,the structure of the buffer layer,which is an important part of the alarm,is a foam material.There is a layer of white flaky material in the inner layer,which is convenient for oil to enter the buffer layer,and a layer of cloth to fasten the buffer layer in the outer layer,and there is a hollow steel pipe for connecting the buffer layer and the alarm.By analyzing the material,the buffer layer is a foamed EPDM rubber,the cells are in the shape of oblate spheres,and the size of long side is about 200 microns.(4)The structural details of the hose are designed by theoretical calculation with the properties of the selected material as parameters such as tensile strength and density.When the aramid cord fabric is 8 layers,burst pressure is 6.7 times the working pressure and the buoyancy reserve is 21.1%,which meets the requirements. |
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