Radiator silicone tube & hose production technology

1, mixed rubber processing
At present, silicone rubber is generally used directly, and crosslinking agents and heat stabilizers or colorants are added before use. It is generally added on the open mixer, but the control roll temperature is below 50 ° C, and it is best to use appropriate tooling to thin pass it to promote the compatibility and uniformity between various adjuvants and silica gel.
A, in order to increase the compatibility between the color powder (colorant) and silicone, generally before mixing, the color powder and 110 silicone (methyl vinyl silicone, the current domestic 110-2) are mixed and processed into color master glue.
B, now common vulcanizing agents are: ①DCBP, commonly known as "double 2,4", peroxide double (2, 4-dichlorobenzoyl), paste DCBP DCBP and silicone oil dispersion. ②BP(benzoyl peroxide). Paste BP is BP with 110-2 silicone rubber (1/1) master glue.)
③DBPH, is the domestic peroxide vulcanization agent -2, 5-dimethyl-2, 5-bis (tert-butyl peroxy) hexane - commonly known as "double 2, 5". ④DCP, diisopropylbenzene peroxide, paste DCP is DCP and 110-2 silicone rubber (1/1) master glue.
C. In order to neutralize the insoluble acidic products produced by the high temperature vulcanization decomposition of peroxide vulcanizing agent, and solve the problem of spraying frost after the silicone tube is parked, silicone anti-frost agent can be added appropriately when mixing rubber, its main components are: dimethylsiloxane polymer, silicone oil and metal oxide.
2, silicon rubber and fiber fabric rolling processing
In order to meet the requirements of different properties such as the strength and heat resistance of the silicone tube to adapt to different use environments and conditions, and to ensure the adhesion and compactness between the silica gel and the cloth layer, it is necessary to rub and paste the fabric and silicone rubber before the rubber tube is formed.
At present, the equipment used for hanging glue is generally four or three roller calender, and there are also relatively backward points that use the processing method of directly bonding the fabric with silicone rubber on the open mixer. Sometimes in order to ensure sufficient bond strength between the fabric and the silicone rubber, it is also necessary to soak the fabric with special adhesive treatment before calendering.
At present, the fabrics used are generally aramid cloth, Vinylon cloth, polyester cloth, glass fiber and so on.
Calender operation process description:
(1) Start the calender;
(2) Put the fabric and plastic film into the corresponding bench, set the main machine of the calender to turn forward, insert the fabric into each guide cloth position along the whole machine process until the winding stop, and then insert the plastic film into the guide roll after the calender through the laminating guide roller in the reverse direction to stop the calender;
(3) Strictly control the temperature of the drying roller (No. 1 roller 115±5℃, No. 2 roller 115±5℃, No. 3 roller 110±5℃, No. 4 roller 110±5℃) to ensure that the moisture content of the curtain before rolling meets the requirements of the regulation (1%). If the operation is interrupted, the curtain should be parked for no more than 4 hours after drying to avoid the curtain absorbing water;
(4) Adjust the roll distance of the calender according to the products produced.
(5) Proper control of the amount of glue. Small amount of glue (each roll ≤10㎏) frequently added to maintain a certain amount of accumulated glue between the roll distance, reduce thickness fluctuations;
(6) calendering roller temperature: silicone rubber adheres to the cold roller, the temperature of the roller in the calendering machine during the calendering process should be lower than the upper and lower rollers, and when the surface of the rubber material ripples or sticks to the roller, the roller temperature should be increased;
(7) The rolling speed should be controlled appropriately to reduce the stress relaxation of the rubber material and maintain the uniformity of thickness;
(8) The curtain expansion is controlled by the tension roller to ensure the width of the curtain;
3, fabric and tape cutting
According to the specification requirements of the product molding process, the fabric suitable for different product requirements or different fabric hanging tape of different thickness and adhesive are cut first.
4, molding processing
(1) Extrusion molding: suitable for small caliber, less fabric layer, low pressure, flat type hose or pure hose, generally using cord winding, cord weaving, cord knitting or direct extrusion without cord.
(2) Simple semi-automatic roll forming equipment: Suitable for straight corrugated pipe, straight pipe and other hose, according to the drawing requirements provided by customers and relevant technical standards, after the design of a reasonable hose structure, the use of appropriate thickness of film, tape, tape, etc., and then according to the appearance requirements of different customers on the surface of the hose, wrap cellophane, tape or (and) water cloth tape, etc., on the one hand, the glue and fabric layer to increase a certain pressure, Ensure the density between them, discharge the remaining air, on the other hand, can also increase the brightness and finish of the surface
(3) Sleeve forming: used for bending S-shaped pipes without forks, etc., first make a straight tube with the size of the product mold, and after exhaust the straight tube is directly set on the product mold and then wrap the outer film.
4) Pre-vulcanization molding: the process is relatively advanced, and there are not many manufacturers in China. Mainly for the bellows, the mold is generally about one meter. With the same process as the bending sleeve, the straight barrel with the same size is first made, the only difference is that the outermost and innermost layers of the straight barrel are pre-vulcanized cooked film (tape), and the middle layers are not pre-vulcanized. After the gas is exhausted, wrap the film on the product mold. The advantages of this process are high efficiency, and it can effectively prevent the inner wall of the hose surface from lacking glue and forming film marks.
(5) Simple artificial molding: suitable for rubber hoses with large and more shaped shapes, and other molding methods cannot guarantee the quality of their products. This type of hose in order to ensure a good demoulding, generally to the mold parting processing.
5, vulcanization: at present, there are three main types of vulcanization methods for rubber hoses in China
(1) steam vulcanization tank vulcanization, the drawback of the vulcanization method is that the environment is dirty, and a lot of products must be put into it at the same time to increase the use of rubber hose molds.
(2) Hot water vulcanization, the domestic use of this process is less manufacturers, the shortcomings are the same as the steam vulcanization tank.
(3) electric heating oven vulcanization, the use of the process of domestic silicone tube manufacturers are basically the use of traditional open-door closed oven, still failed to overcome the shortcomings of low vulcanization efficiency; At the same time, there are a small number of manufacturers have taken the recycling rail oven for production, it should be said that the recycling rail oven is the most advanced silicone tube vulcanization equipment: saving mold, high vulcanization efficiency, can be put into the equipment at any time.
6. Rubber hose demoulding
At present, most domestic manufacturers still take the mold manually by brute force to remove the hose from the mold, or take the mold segmentation.