JPS6011153B2 - Method for producing fiber yarn for filters - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a method for producing fiber threads for filters having excellent heat resistance and the like.

Many filters using synthetic resin fiber threads have been developed and are used in a wide range of applications.

Some filters may be used under very high temperature conditions, and for such purposes, the filters are required to have high heat resistance. Heat-resistant filters include, for example, those using fluorine resins, specifically Teflon (trade name), and vinylidene fluoride resin fiber threads, and these are known as excellent filters that have fewer problems such as decomposition and deterioration even at high temperatures. However, since the resin is a thermoplastic resin, it softens at high temperatures and may cause problems with filter properties, such as elongation or dimensional deformation due to certain loads, causing distortion of the filter mesh. There were drawbacks.

On the other hand, aromatic polyamide containing polymetaphenylene isophthalamide as a main component is used as a resin fiber yarn that has extremely excellent heat resistance and hardly causes the above-mentioned elongation or dimensional deformation even under load at high temperatures. There is a type of fiber yarn, and I tried to use it as it is for filters.

However, when a knitted filter is made using spun yarns of aromatic polyamide fibers containing polymetaphenylene-sophthalamide as a main component, the spun yarns are crushed in the areas where they overlap, causing the filter mesh to become distorted and reducing filter properties. I couldn't help but feel sad that this was happening. In order to solve this problem, the inventors conducted intensive studies on high-temperature filter fiber yarns, and added fluorine resin to the spun yarns of aromatic polyamide fibers whose main component is polymetaphenylene-sophthalamide. The inventors have completed this invention by discovering that monofilament yarn on which a coating layer has been formed can eliminate the above-mentioned drawbacks and become a filter yarn with stable characteristics.

That is, in this invention, a fluororesin powder is attached to a spun yarn of aromatic polyamide fiber containing polymetaphenylene isophthalamide as a main component, and the fluororesin powder is heat-treated at a temperature at which the fluororesin melts. This is a method for producing a fiber thread for a filter, characterized in that a fluororesin coating layer is formed and fixed.

As the aromatic polyamide fiber containing polymetaphenylene isophthalamide as a main component used in this invention, a large number of fibers known to have excellent heat resistance can be used without particular limitation. Specifically, there are spun yarns made of fibers such as Nomex (trade name) (DuPont) and Conex (Teijin Ltd.). Next, the fluororesin used in this invention is 4-
These include fluorinated ethylene-ethylene copolymer resin, 4-fluorinated ethylene-6-fluorinated propylene copolymer resin, 3-fluorinated ethylene chloride resin, vinylidene fluoride resin, and the like. Such a fluororesin is used in the form of a powder, and a method for attaching this fluororesin powder to a spun yarn of aromatic polyamide resin fiber containing polymetaphenylene isophthalamide as a main component is to A method in which the spun yarn is simply passed through the fluorine resin powder, or a method in which water or a solvent is applied to the spun yarn in advance and the spun yarn is passed therethrough, and a method in which the spun yarn is passed under the fluorine resin powder while flowing down.
Furthermore, a method such as a so-called electrostatic powder coating method is effective.

The reason for using fluororesin in this invention as mentioned above is that other resins such as epoxy resin, melamine resin,
Similar coating treatments were carried out using phenoxy resin, polyvinyl acetal resin, etc., but yarns that were flexible and had excellent properties such as heat resistance and chemical resistance could not be obtained, both of which are required for filters. This is because the above performance requirements were not met.

Next, in this invention, the fluororesin powder attached to the spun yarn of aromatic polyamide fiber containing polymetaphenylene-sophthalamide as a main component is heated and melted, and the temperature is set at a temperature equal to that of the fluororesin. It goes without saying that the temperature should be higher than the melting point, and it is usually best to pass it through a furnace heated to 300 to 35,030 degrees Celsius.

The aromatic polyamide fiber containing polymetaphenylene isophthalamide as a main component does not melt at all at the Kuzumushi point of this fluororesin.

The filter fiber yarn obtained by this invention has a fluororesin coating layer formed on the surface of the spun yarn of aromatic polyamide fiber whose main component is polymetaphenylene isophthalamide, so it has excellent heat resistance and , it does not deform even if a certain kind of load is applied under high temperature conditions, so even if it is used for filters used under high temperature conditions, the mesh etc. will not be distorted and its filter characteristics will be maintained for a long time. It is effective and has great industrial value.

Specific examples of this invention will be described below.

Example 1 A spun yarn (2 de x 51 Yanagihara cotton, 3 flotsam) made of aromatic polyamide fiber containing polymetaphenylene sophthalamide as a main component (Teijin Ltd., trade name: Cornex) was 4- The yarn was passed through fluorinated ethylene-ethylene copolymer powder (Asahi Glass Co., Ltd., trade name: Afron COP) to adhere to the surface of the spun yarn, and then passed through a flame using a propane gas burner to heat it.

The obtained spun yarn had almost no fuzz and was in the form of a single monofilament.

The threads were overlapped in a mesh pattern and a load of 100 hours was applied, but the overlapping parts of the threads were not crushed and the mesh did not undergo any deformation or distortion. For comparison, the above-mentioned spun yarns were similarly stacked in a mesh pattern and subjected to the same load test, but the overlapping portions of the threads were largely crushed and the mesh was significantly deformed.

Example 2 Using the same spun yarn as in Example 1, it was first passed through a burner flame to burn off the fuzz on the spun yarn, and then the monofilament was subjected to the 4-normalization process used in Example 1. Ethylene-ethylene copolymer powder was applied to the spun yarn using an electrostatic coating gun.

Next, this was passed through a 350 CO furnace to obtain a monofilament-like yarn coated with fluororesin to a thickness of 150 mm.
Regarding this yarn, a load test was performed on the mesh similar to that in Example 1, but no deformation of the mesh was observed.

Furthermore, this thread was immersed in 100% sulfuric acid for 5 minutes, but no abnormalities were observed. For comparison, a spun yarn not coated with fluororesin was soaked in the same manner, but it was easily dissolved. Example 3 The aromatic polyamide fiber spun yarn containing polymetaphenylene sophthalamide as a main component from Example 1 was passed through vinylidene fluoride resin powder to adhere the resin powder, and then the yarn was heated in a propane gas flame. A thread coated with vinylidene fluoride resin was obtained.

This thread is in the form of a monofilament that is fixed to one piece, and when this thread is woven into a wire mesh, there is no irregularity in the mesh, compared to a mesh made from simply spun yarn of untreated aromatic polyamide fibers. The filter characteristics were much better.

Claims (1)

[Claims] 1. A fluororesin powder is attached to a spun yarn of an aromatic polyamide fiber containing polymetaphenylene phthalamide as a main component, and the fluororesin powder is heat-treated at a temperature at which the fluororesin melts, thereby coating the spun yarn with a fluororesin. A method for producing fiber yarn for filters, which comprises forming and fixing layers.