Application of polyester dipping line in hose

The polyester dipping line is a skeleton material commonly used in the production of hoses, and its function is mainly to improve the compressive strength and rigidity of the hose. The rubber hose braided or wound with dipped wire has the advantages of light and soft tube body, high compressive strength, good bending performance, and the strength of the wire as a skeleton material can be fully utilized. Therefore, in the design of the hose, it is particularly important to select the appropriate polyester dipping line as the skeleton material, and it is particularly important for the technical and economic indicators of the hose to meet the needs of users.

In the past, the skeleton materials used in the production of braided (or wound) rubber hoses in my country's rubber hose manufacturers were cotton fibers, such as 21S/4 x 3, 21S/3 X 3, 21S/2 X 3 and other specifications of cotton thread. Because cotton thread is more convenient to process and has better adhesion to rubber, it is more commonly used in rubber hoses with medium, low and pressure fibers woven (or wound). However, the specific gravity of the cotton fiber is large, the strength is low, the thread is light and thick, and the outer diameter of the braided (or wound) hose is large. into the international market. With the continuous development of the hose industry, higher requirements are also placed on the performance of the selected skeleton material. Manufacturers are also looking for new fiber materials to replace cotton thread.

The strong rayon of synthetic fiber has the advantages of high strength, low elongation, heat resistance, fatigue resistance and good dimensional stability, etc., and is quickly adopted by various hose manufacturers. Because the strong rayon is lighter and thinner than the cotton fiber, the specific gravity is higher, the elasticity is higher, and the strength is higher. , narrowing the gap with similar foreign products, so that my country's rubber hoses have entered the international market. It also saves a lot of cotton fiber and raw rubber, bringing considerable economic benefits. However, the surface of rayon is smooth, and the wire layer is easy to shift when used directly, which is difficult to control and operate, and it is difficult to bond with rubber.

The use of viscose strong rayon can be said to promote the technological development of the hose industry. However, there is no obvious superiority in the production process of the hose, and it only solves the problem of substitution of cotton fiber materials. Because the surface of the rayon used was not dipped at first, the manufacturer must rely on dipping glue to improve the adhesion and solve the adhesion problem of the skeleton layer and the displacement of the wire layer. The process of dipping glue is complicated, and the dipping and drying processes are difficult. Drying after dipping is not only troublesome, but also leads to many quality problems.

With the rapid development of my country's chemical fiber industry, various synthetic fibers for hoses have been introduced. In addition to viscose fiber (strong rayon), vinylon (polyvinyl alcohol) fiber, nylon fiber (polyamide) fiber, polyester (poly ester) fiber, etc. In order to find a more ideal alternative skeleton material, many hose manufacturers are constantly trying to select new synthetic fiber materials for testing and production. The comprehensive performance of vinylon thread is better than that of cotton thread, and its breaking strength can be twice as high as that of cotton thread, but its wet heat performance is poor. Rubber fiber thread and vinylon thread, but the modulus of nylon thread is low, the dimensional stability is poor, the rubber tube produced is easy to deform, and it is not suitable. Through performance comparison and practical use, it was found that polyester dipping fiber is the most ideal hose skeleton material. Compared with other fibers, polyester fiber has the highest strength holding rate after high temperature steam vulcanization, and the strength drop after heating is very small, which can be ignored; and the elongation change rate is the smallest.

The polyester dipping line has the following characteristics:

1. High breaking strength. The compressive strength of the hose is mainly borne by the skeleton layer. Improving the inherent strength of the skeleton material will help reduce the structural level of the hose, improve the performance of the hose, reduce the weight per meter and reduce the cost. 5. Good fatigue resistance and high modulus. The biggest feature of the hose is its superior flexibility, and the improvement of the flexural fatigue resistance of the hose and the resistance of the skeleton material is closely related to the fatigue resistance of the skeleton material.

2. The elongation at break and the elongation at constant load are well controllable, the twist of the wire diameter is uniform, the dimensional stability is good, and the elongation of the skeleton material is small, which will make the expansion deformation of the hose under pressure. Brake pipe is made of polyester dipped wire, and the elongation at break can be controlled at 8% to 10%, so that the expansion rate of the brake pipe can meet the requirements.

3. Small dry heat shrinkage and good high temperature stability. If the skeleton material shrinks and deforms or reduces its strength under high temperature conditions, it will adversely affect the performance of the hose, thereby affecting its service life. For example, the dipping ester wire for air-conditioning pipe, the dry heat shrinkage can be controlled to <1%, so that the deformation of the air-conditioning pipe during the vulcanization process is very small.

4. Good adhesion to rubber. In order to make the overall structure of the hose tight, in addition to the compounding of the rubber and the manufacturing process, the bonding performance of the skeleton material to the parts of the rubber layer is very important. If treated with special formula, EPDM rubber can also achieve ideal adhesion.

5. Good fatigue resistance and high modulus. The biggest feature of the hose is its superior flexibility, and the improvement of the flexural fatigue resistance of the hose is closely related to the fatigue resistance of the skeleton material.

6. Good chemical resistance. When the hose transports various media, it will not affect the performance of the hose.

7. The price is low and the supply is sufficient, which can meet the mass production. This has practical implications for the wide application of materials. The above characteristics of polyester (polyester) dipped thread fully meet the structural characteristics and specific application requirements of fiber braided (or wound) rubber hose.

Due to the excellent performance of polyester dipping line, it is widely used in various fiber braided or wound rubber hoses, such as automobile brake pipes, air conditioning pipes, military hoses, etc. Glue polyester thread.

The only disadvantage of polyester dipping thread is that it is easy to decompose under high temperature steam, especially in the presence of amine, which reduces its performance. Therefore, when using polyester fiber (polyester) thread to manufacture products, it should be avoided in the compound formulation. There are amine complexing agents.

The polyester dipped thread has ideal comprehensive properties, its strength is 15 to 20% higher than that of rayon, the weight per unit length is 40% lighter than that of rayon, and the diameter of the thread is about 40% thinner than that of rayon. Therefore, in the hose of the same pressure level, the amount of polyester thread is small. The skeleton layer can be cut thin, and the outer diameter of the finished hose can be generally reduced by more than 1mm, saving a lot of raw rubber and increasing the burst pressure of the hose. Due to the good adhesion of the polyester dipping line, the traditional dipping and drying processes are removed in the production process, which not only saves man-hours, simplifies the process, shortens the production cycle, facilitates continuous production, but also saves a lot of solvents and energy. quality of the hose.

The polyester dipped fiber yarn produced by Suzhou kingdom textile technology co., Ltd not only has high breaking strength, small unit mass, stable elongation, uniform wire diameter and twist, small thermal shrinkage, and good adhesion; complete. Suzhou kingdom textile technology co., Ltd is willing to do its part to simplify the hose production process, save energy, improve efficiency, improve product quality, promote product upgrades, and occupy domestic and international markets.