JP3534043B2 - Pleated shaped filter material - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates consists partially thermally crimped high basis weight nonwoven fabric by embossing roll pulley
The present invention relates to a filter material that has been subjected to a mold processing .

[0002]

2. Description of the Related Art A continuous filament spun from a spinneret is pulled at high speed by an air sucker or the like, and then colliding and charged on a collision plate mainly composed of lead to open the filament, and then collected on a moving net conveyor. It is common to partially thermocompress with a heated embossing roll to form a non-woven fabric, or to mechanically entangle the laminated web collected on a net with a needle punch to form a non-woven fabric, industrial materials, civil engineering. It has a wide range of uses such as materials, and in particular for filters, it has high performance, excellent durability and processability, so demand for it as a substitute for paper filters is increasing.

The filter base material is required to be a high-quality non-woven fabric which has a small amount of eye spotting and has no partial peeling defect of the sheet, because a partial defect greatly affects the performance of the filter.

Therefore, for example, the basis weight of the sheet is 120 g.
The possibility of using a high basis weight non-woven fabric such as / m ² or more as a filter substrate has begun to be examined.

[0005]

However, a non-woven fabric having a high basis weight, such as a sheet basis weight of 120 g / m ² or more, generally has a poor thermocompression bonding property in the thickness direction even when it is thermocompression bonded by an embossing roll. If sufficient, delamination is likely to occur in the central portion of the thickness, and due to stains on the surface of the embossing roll, the embossed sheet is easily picked up by the roll and the surface layer of the nonwoven fabric is partially peeled off. Therefore, when such a nonwoven fabric is pleated for a filter,
Not only is it not perfect as a filter substrate because the pleating processability is not good, and leakage of fine particles occurs from the part where it is partially peeled off.

The present invention has improved the above-mentioned conventional drawbacks, that is, it is excellent in pleating processability, does not peel off the sheet, and is pleated by the pleating process.
The filter material made is to provide cents.

[0007]

The present invention employs the following means in order to achieve such an object.

That is, the pleats of the present invention have been processed
Filter material made the wick high melting point component, the sheath is a partially thermocompression-bonded nonwoven comprising a sheath-core filament which is a low melting point component, against the non-crimp portion of the crimp portion of the nonwoven fabric
The thickness retention rate is 65% or less, and the basis weight is 200 to 3
And it is characterized in a 60 g / m ² der Turkey.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The basic idea of the present invention is to use a core-sheath type filament in which a core has a high melting point component and a sheath has a low melting point component as a filter material composed of a non-woven fabric. In addition, by using a non-woven fabric having a very large basis weight of 200 to 360 g / m ² , good filter collection performance and shape retention after pleating are realized.

The non-woven fabric as a constituent material of the filter material formed by pleating according to the present invention comprises a core-sheath type filament having a high melting point core and a low melting point core. , The basis weight is in the range of 200 to 360 g / m ² , and is partially thermocompression bonded.

If the basis weight is less than 200 g / m ^2, it may be inconvenient in some cases, such that the filter material may not be able to reach a desired level and the filter material may need to be replaced frequently depending on the application. On the other hand, if it is more than 360 g / m ² , pleating becomes difficult, and although the filter performance is good, it may not be practical as a member for constructing the device.

The nonwoven fabric used in the present invention has a unit weight (X:
g / m ² ) and the bending resistance (Y: mgf) represented by the following equation are preferably 0.03 or more. It is more preferably 0.036 or more.

Y / X ² ≧ 0.03, but X ≧ 200 If such a value is less than 0.03, the pleated portion is not sharp and lacks uniformity because of insufficient rigidity of the nonwoven fabric. Not only is the workability poor, but it is difficult to even incorporate it into the filter unit.

The pressure-bonding area of the non-woven fabric is preferably 3
It is preferably 5% or less, more preferably 30% or less in order to improve the pressure loss of the filter and the filter life. If it exceeds 35%, the thickness of the non-woven fabric is reduced, but the pressure bonding efficiency is reduced and the pressure bonding depth becomes shallow, which tends to facilitate delamination, which causes the pleated portion to be removed during pleating. It is easy to cause the problem of peeling and dust leakage from the same part, and further it may lead to filter defects due to poor workability when incorporating it in the filter unit or poor sealing property of the non-woven fabric peeling part when fixing resin to the unit. Problems are more likely to occur.

In the present invention, the thickness retention ratio of the crimped portion to the non-crimped portion is clear from the examples.
To 65% or less, it is preferably 33 to 63%
Is important . When the thickness retention of the crimping portion exceeds 65%, even without apparent disadvantage of the nonwoven surface layer portion for crimping force is insufficient, when the bending such as pleating, adhesion points peels off, so-called Delamination occurs,
It becomes difficult to obtain a satisfactory filter base material such as filter performance and pleating performance.

As in the present invention, in the case of a non-woven fabric having a high basis weight of 200 g / m ² or more, the filament constituting the non-woven fabric should be of a core-sheath type consisting of two components, a high melting point component and a low melting point component. is important. For example, in the case of a filament of a single component such as a high melting point component, simply increasing the temperature and pressure of the embossing roll often results in insufficient adhesion, resulting in delamination, filter performance, and pleating. It is difficult to obtain satisfactory filter base materials such as performance. Alternatively, if the filament is a single-component filament with good adhesiveness, such as a low melting point, the thermal adhesiveness is improved, but the strength of the filament is so small that the strength of the filter is low, It is generally difficult to obtain a filter substrate that is satisfactory in terms of stability.

It is also conceivable to impregnate a resin such as an acrylic resin in order to cover the adhesive force of the filament, but in such a case, the void ratio of the filament constituting the non-woven fabric is reduced and the dust collection efficiency is reduced. It should be avoided as it will cause new problems such as a decrease in.

The high-melting point and low-melting point polymers used for the filament may be any resin such as polyester, nylon, polypropylene or copolymers thereof, or those obtained by adding a third component to these polymers. May be adopted. Further, the filament form of the low melting point component and the high melting point component in the present invention is a core-sheath filament in which the high melting point component is coated with the low melting point component.

In the present invention, the ratio of the low melting point component is preferably in the range of 5 to 30% by weight with respect to the total fiber components, and when the ratio of the low melting point component is less than 5% by weight,
A portion where the low-melting point component cannot cover the high-melting point component is likely to occur. In that case, spun yarn breakage easily occurs in the non-covering portion, and product defects easily occur. On the contrary, when the low melting point component exceeds 30% by weight, it is effective to raise the temperature of the embossing roll to a temperature close to the melting point of the low melting point polymer, and the embossing roll is apt to be contaminated. It is difficult to provide a filter base material which is difficult to be peeled off and is likely to cause partial peeling at the surface layer of the nonwoven fabric.

Further, the fineness of the filaments constituting the non-woven fabric is preferably in the range of 1 to 10 denier. When the fineness is less than 1 denier, it may be difficult to collect the product due to poor spinnability. There are many problems such as low productivity and unprofitable results. Also, 1 denier
When it is larger than 0 denier, there is a problem that the filter efficiency is lowered due to the insufficient number of fiber constituents, and it tends to be unsuitable for filter applications.

The pleated-shaped filter material of the present invention is composed of a high-density nonwoven fabric having a weight of 200 to 360 g / m ^{2, and} has filter characteristics of high collection performance and good pleating workability. And the shape retention thereof can be achieved at the same time.

The engraving pattern of the embossing roll for producing the filter material of the present invention, which is processed by pleating , is not particularly limited, but preferably the engraving depth is about 0. A thickness of about 5 to 1 mm keeps the thickness retention ratio of the crimped part to the non-pressed part of the non-pressurized nonwoven fabric having a high basis weight of 65% or less, and the weight of the non-woven fabric (X) and the flexibility (Y). This is preferable because the relationship can be optimized to Y / X ² ≧ 0.03.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples. The method of measuring the characteristic values shown in the examples is as follows. [Bending flexibility] 2 pieces per 1 m width of non-woven fabric sample (vertical direction)
Is cut into a size of 1 inch × 1.5 inch, and two pieces are sampled. Using this sample, JIS L-10
It evaluated based on 86-6.13. [Unit weight (g / m ² )] The weight of a non-woven fabric measuring 1 m vertically and 1 m wide was measured. [Thickness retention rate (%) of pressure-bonded portion] Thickness A of non-pressure-bonded portion A: TECROC having a disk diameter of 10 mm according to JIS L-1085 dial gauge method
It was measured with a thickness meter.

Thickness B of pressure-bonded portion: A cross-sectional photograph of the pressure-bonded portion was taken with a scanning electron microscope at a magnifying power of 100, the dimensions were checked with a caliper, and the calculation was performed backward from the magnification.

Based on these results, the thickness retention of the crimped portion was calculated by the following equation.

Thickness retention rate (%) of the pressure-bonded portion = B / A × 100 [Sheet peeling] A sample having a width direction of 20 cm and a length direction of 80 cm was bent into an arc shape having a radius of 10 cm over the entire length direction and peeled. The situation was evaluated according to the following criteria.

Evaluation criteria ◯: No peeling was observed.

Δ: One peeling less than 2 cm.

X: The number of peeled pieces is 2 or more. [Pleatability] A sheet having a width of 50 cm and a length of 300 m was bent by a rotary pleating machine, pleated to a pitch of 3 cm, and evaluated according to the following criteria.

Evaluation Criteria ◯: The pleats are sharp and uniform, and the sheet does not meander.

Δ: The pleats are slightly non-uniform and slight meandering is observed, but there is no problem in use.

X: The pleats are non-uniform and the sheet is meandering, which causes a problem in work when incorporating the filter unit. Example 1, Comparative Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.66 and a melting point of 262 ° C. and an intrinsic viscosity of 0.68 and a melting point of 228.
After melting the isophthalic acid copolyester having a temperature of ℃ in a separate extruder, the filament has a denier of 2 denier, and the ratio of the low melting point component in the whole fiber is 15
The discharge amount was adjusted so as to be 100%, and the core-sheath filament was spun from the spinneret capable of core-sheath spinning. Subsequently, the spun filament was pulled by air soccer at a high speed of about 5000 m,
The filament was made to collide with a collision plate, the filament was opened, and the filament was jetted onto a moving net conveyor, and further collected to obtain a nonwoven web.

At this time, the speed of the net conveyor was changed so that the basis weight was 120 g / m ² (Comparative Example 1) and 200 g / m.
² (Example 1- (1) to (3)), 260 g / m ² (Example 1- (4) to (6)), 360 g / m ² (Example 1
-(7)-(9)) non-woven fabric with engraving depth of 0.8 m
m, the area of the press-bonded portion was 15%, and the temperature was 220 ° C. The embossing roll pressure was changed, and thermocompression bonding was performed. Subsequently, after setting the sheet width to 50 cm, it was pleated with a rotary pleating machine. The results are shown in Table 1.
It was shown to.

[0034]

[Table 1]

As can be seen from Table 1, Example 1 is satisfactory as a filter material since it does not cause delamination of the sheet and has good pleating workability and shape retention. Example 2 A nonwoven fabric having a basis weight of 220 g / m ² was used in the same manner as in Example 1, the engraving depth was 0.8 mm, and the pressure-bonding area of the embossing roll was 5% (Example 2- (1)). % (Example 2- (2)), 15% (Example 2- (3)), 20%
(Example 2- (4)) and 30% (Example 2- (5)) were subjected to thermocompression bonding for 5 levels. Continue to increase the sheet width to 50
After cutting into cm, pleating was performed with a rotary pleating machine. The results are shown in Table 2.

[0036]

[Table 2]

As is clear from Table 2, in Example 2, no fluff was generated, and there was no problem in peelability and pleating processability. Example 3 Polyethylene terephthalate having an intrinsic viscosity of 0.66 and a melting point of 262 ° C. and an intrinsic viscosity of 0.68 and a melting point of 228
After melting the isophthalic acid copolyester having a temperature of 0 ° C. in a separate extruder, the denier of the filament is 2 denier, and the ratio of low melting point in the whole fiber is 30%,
The content was changed to 20%, 10%, 5%, the sheath component was made of copolymerized polyester, a core-sheath type spinneret was used, and a core-sheath filament was spun by high-speed spinning at about 5000 m / min by air sucker. The spinnability is good and the basis weight is 200
The sheet was g / m ² . The area of the crimping part continues to be 15%
The resulting sheet was thermocompressed with an embossing roll having a temperature of 200 ° C. and pleated with a rotary pleating machine to produce a filter. As a result, delamination of the obtained sheet did not occur and it was a good result as a filter material. It was Example 4 In the same manner as in Example 3, the ratio of low melting point contained in all the fibers was set to 15%, and the denier of the filament was 1 denier and 2
The spinning was performed after changing the denier to 5 denier and 10 denier. Single denier increased single yarn breakage and 10 denier increased yarn breakage due to insufficient cooling, but this was at a level at which there was no problem in operation, and a sheet having a basis weight of 300 g / m ^{2 was} continuously used.
The sheet obtained by pleating the sheet after thermocompression bonding with the embossing roll with a rotary pleating machine was used as a filter, and there was no delamination and good pleating property. Comparative Example 2 A single component of polyethylene terephthalate having an intrinsic viscosity of 0.66 and a melting point of 262 ° C. was melted by an extruder, and then the discharge amount was adjusted so that the denier of the filament was 2 denier, and high speed traction was performed with an air sucker. Then, the filament is opened and collected on a moving net conveyor, followed by thermocompression bonding with an embossing roll having a surface temperature of 250 ° C.,
A nonwoven fabric having a basis weight of 260 g / m ² was obtained.

This non-woven fabric had insufficient adhesion, had delamination, and was difficult to pleat.

[0039]

According to the present invention, no occurrence of exfoliation disadvantages, excellent performance has appropriate rigidity and shape retention flop
It is possible to provide a filter material that has been subjected to leet shaping .

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B01D 39/00-39/20

Claims (2)

(57) [Claims] 1. A partially thermocompressed non-woven fabric comprising a core-sheath filament whose core has a high melting point component and whose sheath has a low melting point component.
Of the non-crimped portion of the non-crimped portion of the nonwoven fabric
Possession rate is 65% or less, and basis weight is 200-360g /
It is pleated shaping machining, wherein the m ² der Turkey
That filter material. Ratio of 2.] The low melting point component, a 5-30% relative to the fiber weight of the core-sheath filaments, and non-woven
Lower fabric weight (X: g / m ² ) and bending resistance (Y: mgf)
The pleated imprinting process according to claim 1 , which is in the relationship shown in FIG.
Filter material that has been manufactured. Y / X ² ≧ 0.03