Study On The Production Techniques Of HMLS Polyester Industrial Yarn And Dipped Tire Cord Fabric

High Modulus and Low Shrinkage (HMLS) Polyester Industrial Yarn is one of the key chemical fiber products listed in China "10th 5-year Plan", and it is encouraged to develop by national government.Thanks to its good properties of anti-wearing out and dimension stability, the dipped tire cord fabrics made from HMLS polyester yarn are extremely suitable to manufacture radial tires. The amount of HMLS yarn is accounted for 30% of the total output of polyester industrial yarn worldwide.The radial tire in China has been experiencing fast development in recent years, the annual consumption of polyester tire cord fabrics reaches 22,000 ton, and 12,000 ton of the HMLS polyester dipped tire-cord fabrics has to be imported every year. The huge gap of manufacturing HMLS polyester industrial yarn and dipped tire cord fabric can be seen between China and the developed countries. It can not meet the needs of development on domestic tire industry as well. Therefore, to speed up the development of locally made HMLS PES industrial yarn and tire cord fabric and put into industrial production become our top priority.The structure, properties and preparation of HMLS PES industrial yarn were studied in detail. Some technical modifications have been made on the existing equipment in Wuxi Taiji Company, the key process parameters of Solid State PolyCondensation (SSPC), Spinning, Drawing, Winding and Dipping had been investigated and optimized.The key conclusions of this study are as following: 1. When selecting local made Bright PET chips produced via of TPA and polycondensation in optimized processes, the upgraded chips with theviscosity 0.95-1.02dL/g, crystallizability >60% and -COOH content <15mol/106g which are suitable for producing HMLS PES industrial yarn can be produced via SSPC.2. With the technical modifications on the conventional industrial yarn production equipment of Wuxi Taiji, applying the suitable process parameters like low spinning speed (600 - 700M/Min), high drawing-ratio (5-6 times), high temperature & tension heat setting and middle winding speed (3000 -5000M/Min), the HMLS PES industrial with around 5% EASL(Elongation At Specified Load) and 4% - 5% hot air shrinkage (177°C,1 min) can be successfully produced. The quality of the product reached the high level of the similar products from international companies in late 1990's.3. With the high temperatures of drawing (230°C) & setting (235°C), low draw-ratio, and high relaxing ratio during dipping, the HMLS PES dipped tire cord with less than 5% EASL and 2% hot air shrinkage was produced. The trails to manufacturing radial tires with the products had been successfully made, and the results are satisfactory.4. With the technical modifications on the conventional industrial yarn production equipment and application of optimized process parameters, HMLS PES industrial yarn and dipped tired cord which meet the requirements of tire manufacture can be successfully produced.