Polytetrafluoroethylene punched felt and manufacturing method thereof

Abstract

The invention relates to a polytetrafluoroethylene punched felt. From the outside to the inside, the structure of the punched felt comprises a polytetrafluoroethylene crimped staple layer, a polytetrafluoroethylene filament base fabric and a polytetrafluoroethylene crimped staple layer, wherein the thickness of the punched felt ranges from 0.8 to 1.8 millimeters; polytetrafluoroethylene crimped staples mutually hooked and crossed are inserted in the base fabric from upside and downside and tightly connected with the base fabric. The punched felt produced by the invention has the advantages of stable chemical properties, high filtering effect, high strength, low heating shrinkage, low material consumption, low cost, no smoke pollution and the like.

Description

technical field [0001] The invention relates to a needle felt, in particular to a polytetrafluoroethylene needle felt and a manufacturing method thereof. Background technique [0002] Polytetrafluoroethylene, commonly known as Teflon, is known as the "King of Plastics". Its relative molecular weight reaches millions or even tens of millions. , and arranged in a zigzag shape. Due to the large radius of the fluorine atoms, a very stable chemical bond is formed, which can shield and protect the carbon atoms on the main bond, and the molecular chain is difficult to be destroyed. Therefore, PTFE material has good corrosion resistance, heat resistance and oxidation resistance, and is almost not corroded by any chemical reagents except molten alkali metals. Maintain excellent mechanical properties in a wide temperature range; because the dipole moment of PTFE macromolecules is close to zero and basically non-polar, the insulation performance is very good; the surface free energy o...

AI Technical Summary

Problems solved by technology

The fibers produced by the former have poor fiber strength due to the influence of sintering, and there are water pollution problems. The latter is currently a more commonly used production method. Made, the fiber has a high elastic deformation rate in the forward direction, and the fiber stability is poor. Because the breaking strength of the PTFE fiber is lower than that of the general filter material, and the breaking elongation is low, after being made into a needle felt, it is often The strength is low and the heat shrinkage rate is high (>3%), which affects the stability of the filter bag size. Under long-term high temperature conditions, the friction between the filter material and the keel will be damaged or the bag cage will be ejected from the bag. In addition, there are many technical difficulties in the production process of needle felt, such as high static electricity, difficult carding, and large fiber loss.

So far, the technology of completely using 100% polytetrafluoroethylene to produce needle-punched felt is rare. Chinese patent CN200510045562.9 discloses a production method of polytetrafluoroethylene needle-punched felt, which basically involves static electricity elimination, heat preservation and moisturizing. In general carding and needle punching process, there is no clear or effective way to control the heat shrinkage rate, needle felt strength, fiber loss and subsequent treatment of surface floating hair on the felt, and these process points have a great impact on product quality, cost and lifespan. It is very important for this patent, in which the patent mentions that the method of placing polytetrafluoroethylene on a stainless steel cylinder to discharge static electricity can only reduce the charge on the fiber in this step, and does not propose an effective way to eliminate the static electricity generated during the carding process , and this patent adopts the singeing method for the treatment of the floating wool on the surface of the subsequent mat, which is strictly prohibited in the production process of polytetrafluoroethylene products, because polytetrafluoroethylene will produce highly toxic by-products of fluorine light when it is cracked at high temperature Gas and perfluoroisobutylene, etc. Inhalation of these gases will cause nerve paralysis and even life-threatening, so special attention should be paid to safety protection and prevent PTFE from contacting open flames to avoid smoke pollution