JPS60122019A - Filter - Google Patents

Abstract

PURPOSE:To obtain a precision filter having high filtration efficiency and high durability by using a knitted fabric having >=4,500/in<2> stich density prepd. from fibrilated composite yarn having <=0.5 denier fineness of single yarn comprising polyamide and polyester. CONSTITUTION:Said fibrilated composite yarn is, as illustrated by the figures by its cross sectional view, is a composite yarn comprising polyamide and polyester fiber wherein said both fibers are bonded along its longitudinal direction of the single filament wherein one of the component does not completely enclose the other component in the cross section of the single filament. The fineness of the single yarn after fibrilation should be <=0.5 denier. A knitted fabric having >=4,500/in<2> stich density, 10-55% void, and 0.2-10cc/cm<2>/sec permeability for air is used and fibrilated, and the density is increased by extruding under heating at 150-200 deg.C and 150-300kg/cm<2> pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a filter having an extremely dense structure. Specifically, the present invention relates to a dense filter knitted fabric having an extremely high stitch density and an extremely dense structure made of polyester and polyamide fibrils.

(Prior art) Conventionally, W? Filters include paper (so-called P paper), i'Ji molecular membrane with holes, and polymer 1]'W'9 having micropores.

(Problems to be Solved by the Invention) All of these filters have many drawbacks such as poor strength, poor durability, and poor moldability. Furthermore, it is difficult to obtain a sufficiently detailed structure with woven fabrics, and many of them are unsuitable for use in clean filter filters.

An object of the present invention is to provide a filter made of a knitted fabric having an extremely high mesh density, which has a good crab pass rate and excellent r+i:I durability.

(Means to Solve the Problems) In order to solve these problems, the inventors of the present invention have conducted extensive research and found that a method using fibrillated α composite fibers with a stitch density of 1,500 to 4,000 stitches per square inch has been developed. The paulownia wood is treated with a specific chemical to fibrillate the composite fibers, and then subjected to steam treatment under specific conditions to make the paulownia wood.'
It was discovered that a knitted fabric obtained by reducing the shrinkage by 50% or more and having a stitch density of 4,500 or more per square inch has unprecedented properties as a precision filter,
It takes 21 things to complete this invention.

E! 1) The filter of the present invention is made of a fibrillated composite &'& +f+J made of polyamide and polyester and has a single filament fineness of 0.5 denier or less after fibrillation, and has a stitch density of 4,500 or more per square inch. A knitted fabric, in which the composite fibers constituting the knitted fabric are substantially fibrillated, and the porosity of the inner layer of the knitted fabric is 10.
~55%, air permeability 0.2-10, 0 cc/al/s
Being an EC is one of the nine temple signs.

The term "fibril" used in the present invention refers to a large number of finely woven a-fibers that are bundled together to form a fiber bundle. It can be easily obtained by dividing it into each component.

The fibrillated composite fiber in the present invention is a fibrillated composite fiber in which polyamide and polyester are formed into a single filament (in a cross-section, one component does not completely surround the other component, and the fibrillated composite fiber extends along the longitudinal direction of the single filament). Specifically, composite fibers whose cross section is a side-by-side repeating type as shown in Figure 1, a component having a radial shape as shown in Figure 2, and a shape that complements the radial part. Composite fibers consisting of a pond component having Since ultrafine fibrils with a denier of 10 or less are easily produced, composite fibers having a side-by-side repeating cross section with or without hollow portions, and composite fibers with a component having a radial cross section are suitable. but,
In terms of manufacturing conjugate fibers, from the viewpoint of stability of the fiber cross-sectional form, conjugate fibers with a component having a radial moon 4 shape on 4,1"/11 planes are advantageous.

Examples of polyamide include nylon 4°, nylon 6, nylon 7, nylon 11. Nylon 12. Examples include nylon 66, nylon 10, polymethaxylene adipamide, polyno-f laxylylene decanamide, polybiscyclohexylmethanedecaneamide, and copolyamides containing these as components.

Examples of polyesters include polyethylene terephthalate, polytetramethylene terephthalate, polyethylene A-oxybenzoate, i,Q-1,4-dimethylcyclo-\xane terephthalate.

Examples include polypivalolactone and copolyesters containing these components.

The fibrillated fiber M2 needs to have a single fiber fineness of 0.5 denier or less after fibrillation. Normal '4A fineness fibers (for example, fibers with single yarn fineness of 1 denier or slightly lower), fibrillated 1 or composite fibers with single yarn fineness exceeding 0.5 denier after fibrillation, even high-density knitted fabrics. Even so, it is unsuitable for use as a precision filter, and when the fibrillated back metal fibers are fibrillated, if the fibrils have a fineness of 0°5 denier or less, they are not simply aligned but are intertwined with each other. This results in a structure with very narrow gaps, resulting in an excellent precision filter.

The knitted fabric using the fibrillated composite fiber according to the filter of the present invention is Beni 1+'! It may be fj fabric, flat knit fabric, or circular knit fabric, but is not particularly limited.

Furthermore, the fibrillated composite fibers constituting these knitted fabrics are substantially fibrillated.

Here, "fibrillated" means that, for example, when a fibrillated composite fiber has 111 horizontal planes as shown in Figure 1, the junction of the fiber components is separated by -1, and the three segments of one component are separated by -1. It refers to a state in which there are six fibrils consisting of a thread and three segment threads of the other component.For example, when the composite fiber has a cross section of T'' as shown in Figure 2, it is divided into IY6. This refers to the state in which nine fibrils are formed, consisting of one segment yarn with a flat groove cross section and eight segment yarns of the other component with a fan-shaped transverse direction. Furthermore, even if the fibrillated fiber has any other cross-sectional shape, its fibrillated state can be easily inferred from the above description.

Furthermore, the stitch according to the present invention has a stitch density of 4,500 or more per square inch, preferably 5,000 to 10,000.
The porosity of the inner layer of the print is in the range of 10 to 55%,
Further, the air permeability is 0.2 to 10αA24.

Conventionally, it has been difficult to fabricate knitted fabrics with a mesh density of 4,500 or more due to mechanical constraints of the knitting machine, but this has become possible with the present invention.

Here, "inner H7ζ1≦" means that if you look at the cross section of the high-density knitted fabric according to the present invention at iU and IJ, there is an upper outer layer with a higher thread density, then a dense inner layer, and then a sparse lower outer layer. There is debris. Therefore, it refers to this dense inner layer. The porosity is a value expressed as a percentage of the voids obtained by subtracting the actual volume of the thread from the apparent volume of the inner and outer ji:q part of the braid. Moreover, the air permeability is a value measured using a JIS-L-1079 Frazier type tester.

This porosity exceeds 55% or the air permeability is 1054V
If it exceeds the gate, it is not suitable for rectifying filtration, and the porosity is less than 10% or the air permeability is 0°2, -/cd/-
If it is less than that, the filtration efficiency is not good.

The above filter uses fibrillated MIA J fibers made of polyamide and polyester and has a single filament fineness of 0.5' denier or less after fibrillation, and has a mesh density of 1,500 to 4,000 per square inch. After knitting the knitted fabric, the auxiliary shaft is treated with an agent that swells the polyamide to substantially fibrillate the composite fibers constituting the knitted fabric,
Subsequently, the knitted fabric is treated with steam at a temperature of 70° C. or higher to shrink the knitted fabric by 50% or more in terms of area, and the knitted fabric is made to have a stitch density of 4,500 or more per square inch.

The fibrillated composite sail bud used in the present invention has a fineness of 30
~150 denier is preferred.

The filter of the present invention is produced by applying an agent that swells polyamide (hereinafter referred to as "fibrillating agent") to the above-mentioned knitted fabric to promote fibrillation of the Ata fabric, and then applying a fibrillating agent to the knitted fabric. 70° while still attached
It is obtained by shrinking the polyamide mainly by treating it with water vapor of C or more, and shrinking the polyamide by 50% or more by turning the metal fabric into planes 'I and l, and increasing the mesh density to 4.5011 or more per square inch.

Here, the fibrillating agents are generally benzyl alcohol, β-fugonylethyl alcohol, FuSnol + nl-cresol, dA acid, acetic acid, etc. I can get it. It is also commonly used as a water bath solution or an aqueous emulsion. In particular, among the above methods, the method using an aqueous emulsion of benzyl alcohol is a method that allows fibrils to passivity9.
1, and in terms of handling and ease of construction, it is farthest from A, 11''.

In order to make an aqueous emulsion of the above fibrillating agent, a surfactant may be added to the fibrillating agent to increase the emulsion content. agent, anionic activator 2 both i1b i
7! , sex agents, or a mixture thereof.

It is also good to stabilize the emulsion by adding a Jfl adhesive such as a general emulsifier or glue to the river.

The concentration of the fibrillating agent needs to be 1.5% by weight or more in order to obtain a fibrillating effect.

In the fibrillation method applied to the present invention, a knitted fabric using fibrillated composite fibers is impregnated or coated with a chemical. In this impregnation, the material is passed through or soaked in a normal impregnating solution, and then the fluid is squeezed out using a mangle or drained using a dehydrator. Of course, you can apply the 7G according to the usual method. The temperature of the impregnating or coating liquid is 5 to 50°C, preferably 10 to 40°C. It is preferable that the AM content is 1 to 50ffiA%. Does the temperature of the impregnating agent and the pick-up pattern depend on the braiding of the knitted fabric, the degree of softness, or the desired fit? i
The nail should be adjusted appropriately.

After applying the drug, the temperature is 70°C or higher with the certain drug attached,
Preferably, the knitted fabric is subjected to a steam treatment at 90 to 130° C. to mainly shrink the polyamide, thereby shrinking the knitted fabric by 50% or more in terms of area, so that the Ha density becomes 4,500 or more per square inch. Treatment with water vapor at a temperature below 70° C. fails to form a sufficiently dense structure, making it impossible to achieve the object of the present invention. Further, as the water vapor, saturated water vapor is preferable. Unsaturated water vapor may cause spots in the dense structure, while supersaturated water vapor may cause steam ridges to contaminate the knitted fabric, so special care is required. "Also, it is preferable that the water vapor contains the vapor of an agent that causes the polyamide to swell, such as an azeotropic mixed vapor of water and a 1-hemolytic agent, since even higher shrinkage can be obtained.

To achieve the purpose of treating the knitted fabric with water vapor in this way, it is preferable to treat it twice for 2 seconds or more.

However, it is necessary to reduce 171ii by an appropriate G% during processing depending on the pick-up and temperature of the water vapor, etc., for personal practice. In addition, the usual pink up
In the case of water vapor temperature, about 4 to 20 seconds is sufficient.

In this way, the 14J high-density knitted fabric can be further increased in km degree by subjecting it to heat-pressure door processing, if necessary. For example, thermal compression processing is performed at 150 to 20
This is done by suppressing heating using a thermal calendar maintained at 0°C. The degree of pressure is approximately 150 to 300 V/■ depending on the purpose.

(Example) The present invention will be explained in more detail with reference to Examples below.
Of course, the present invention is not limited in any way by these embodiments.

Example 1 A 50 denier/25 filament fibrillated composite fiber having a cross section as shown in FIG. 2 and using nylon 6 as the A component and polyethylene terephthalate as the B component was used. An interlock knitted fabric was knitted using the gauge Maru FiMP&. The Myanmar jllll
The pure A degree was 2800/in2.

The knitted fabric was treated with; benzyl alcohol at 30°C; 3()% aqueous emulsion (2% of Sunmo/l/B K-20 manufactured by Nippon Y1ze Kagaku ■ was used as an emulsifier); fin, Fr inside;
i n' kushita. The big amplifier rate of the emulsion is 7
It was 0%/knitted fabric. V (and the knitted fabric is 1 (l O'
A wet heat treatment was performed using saturated steam of C for 10 seconds to remove benzyl alcohol for 5 J, followed by washing with water to sufficiently remove benzyl alcohol and drying. Thereafter, the obtained fibrillated knitted fabric was heat set at 180° C. for 60 seconds, and this was designated as knitted fabric F-1.

F-1 has a cuff density of 6,500/square inch and a void ratio of 4.
The air permeability was 8% and the air permeability was 3.5 cc/rin. The surface and cross section of F-1 were enlarged and observed using a scanning electron microscope, and it was confirmed that the composite fibers were almost completely fibrillated.

Example 2 In order to investigate the p overaccuracy of knitted fabric F-1, JIS-Z-8
When 8 test dusts of 901 were dispersed in water and passed through F-1, the remaining residue and p liquid were observed under a microscope.
Particles larger than ~5 μm were captured by F-1. Based on this, the performance of F-1 was evaluated in comparison with a 5 μm class filter.

As a performance evaluation, P water velocity and average flow rate were measured. Here, the P water velocity means that a cylindrical filter with a diameter of 45 gm is set with a separation filtration surface (1112 t* filter, 2 (lQ mg of pure water is placed in the filter, and 1 QQa = pure water is naturally produced under no pressure. It is the time required for filtration.Also, the average flow rate is 1000 pp of 8 types of test dust in pure water.
This is the average flow rate (rnI!/d/win) when a liquid dispersed at a concentration of m is filtered at a pressure of 2 KQ/d.
('l Ome 7'c#lPA The average flow rate when doing this was defined as the average flow rate ■.

The filters used were F-1 of the present invention, and Toyo P Paper Layer 3 and Toyo Membrane Filter-TM-50 as control products.
0 (all 5 μm class Toyo P paper (manufactured by 4) was used.

The results are shown in Table 1.

Table 1 In this experiment, the collection efficiency C of particles of 5 μm or more was good, at 90% or more.

As is clear from Table 1, the F-H meteor of the unexploded jJ is large, and the flow rate drop during filtration is also small17).

Example 3 Example 1!・In order to further increase the density of -1, use a thermal calendar!・L was applied. That is, ←゛-1 to 190℃
Calendar roll held at G1 to 250 to 9/-
Heat-pressed under pressure: Processed, porosity 14%, air permeability 0
．． 3 戊/-μ no shrine jl'41? -2 was obtained.

The 17 degree filtration of this F-2 was examined in the same manner as in Example 2, but using a test tube, 0.8
Particles larger than ~1 μm were captured.

Based on this, the average dispersion of the 0.8 μn; class filter and Example 2 was evaluated. However, 11 types of test dust were used. The control product is Nucleop.

Re Corp (U.S.A.)'JA's N080 V).

The results are shown in Table 2.

Table 2 (Effects of the invention) The filter of the present invention has a hardness of 0.8 to 10 μm class.
It is suitable as a precision filter for separation, and its advantages are as follows.

(1) If the filtration efficiency is low, there is little decrease in the amount of Mf in the vortex.

(2) Strong and durable.

(3) Reusable.

(4) Flexible, I7! , l-cutting, 1 "i-bending, easy to bond, and easy to crack.

(5) It has excellent 11i-1 chemical properties.

(6) Excellent antibacterial properties compared to cellulose-based materials (cotton, tP, la', .).

[Brief explanation of drawings]

Figures 1 to 3 show fibrillated T that can be used in the present invention.
! 1. Examples of cross sections of composite fibers are shown in Fig. 1. Fig. 1 shows a composite fiber whose cross section is side-by-side repeating, and Fig. 2 shows a component whose cross section has a radial shape and a pond whose cross section has a shape that complements the radial part. Fig. 3 shows a side-by-side repeat type conjugate fiber with a hollow section in cross section. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) Made of fibrillated m-composite fibers made of polyamide and polyester and having a filament fineness of 0.5 denier or less after prilling, the stitch density is 4.5 per square inch.
A knitted fabric of 00 or more, which is a composite fiber that forms the semi- or full-length part of the knitted fabric; .2～
4 temples that 10°Occ/7/sea? A filter with a border.