KR101802130B1 - Method for Manufacturing Polyester Spunbond Nonwoven Fabric - Google Patents

Abstract

Disclosed is a method for producing a polyester spunbonded nonwoven fabric capable of realizing a reduction in manufacturing cost and an improvement in tensile strength of a nonwoven fabric by performing thermal bonding of webs at a relatively low temperature. The method of the present invention comprises the steps of co-spinning a first polyester having a melting point of 240 to 270 캜 and a second polyester having a melting point of 180 to 220 캜, forming a web with the filaments formed by said composite spinning And thermally adhering the web at < RTI ID = 0.0 > 100 C < / RTI >

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester spunbond nonwoven fabric,

The present invention relates to a method of producing a polyester spunbonded nonwoven fabric, and more particularly, to a polyester spunbonded nonwoven fabric capable of reducing manufacturing cost and improving tensile strength of a nonwoven fabric by performing thermal bonding of webs at a relatively low temperature And a method for producing the same.

Polyester spunbond nonwoven fabrics have high productivity, high strength and low toughness, and are used in many industrial fields. Polyester spunbonded nonwoven fabrics are widely used in automobiles because they have high strength and excellent drainage properties and are used in civil engineering and construction applications and have excellent durability at low cost. Particularly, it has been recently found that the polyester spunbonded nonwoven fabric has excellent shape stability and dust particle collecting ability, and it has been widely used as a filter material.

The present applicant filed a Korean patent application No. 10-2007-0134912 for a method for obtaining a polyester nonwoven fabric having a high tensile strength, and this was registered as No. 10-1079804 (hereinafter referred to as' 804 patent). The '804 patent discloses a method of forming a web in which a low-melting-point copolyester fiber and a regular polyester fiber are mixed through a mixed-spinning process of a low-melting-point copolyester and a regular polyester, So as to improve the tensile strength of the nonwoven fabric by melting the low melting point copolyester fiber.

However, in order to melt the low-melting-point copolyester fiber through the heat-bonding process, the heat-bonding step had to be carried out at least at a temperature of the melting point of the low-melting-point copolyester fiber, for example, around 200 ° C.

Although the melting point of the low melting point copolyester fiber is relatively lower than the melting point of the regular polyester fiber but is still at a high level when it is absolutely evaluated, a high heating cost for the heat bonding process is still a problem, The heat applied to the web during the process causes damage of the regular polyester fiber, thereby causing the problem that the tensile strength of the nonwoven fabric is lowered.

Accordingly, the present invention relates to a process for producing a polyester spunbonded nonwoven fabric which can prevent problems due to limitations and disadvantages of the related art.

One aspect of the present invention is to provide a method of producing a polyester spunbonded nonwoven fabric which can realize a reduction in manufacturing cost and an improvement in tensile strength of a nonwoven fabric by performing thermal bonding of webs at a relatively low temperature.

Other features and advantages of the invention will be set forth in the description which follows, or may be learned by those skilled in the art from the description.

According to one aspect of the present invention, there is provided a method of producing a composite yarn, comprising the steps of: spinning a first polyester having a melting point of 240 to 270 DEG C and a second polyester having a melting point of 180 to 220 DEG C, Forming a web, and thermally adhering the web at < RTI ID = 0.0 > 100 C < / RTI > or less.

The second polyester may be a copolyester made from copolymeric monomers comprising adipic acid, isophthalic acid, or mixtures thereof.

The amount of the second polyester among the first and second polyesters used in the composite spinning step may be 5 to 20 wt%.

The filaments formed by the composite radiation may have a sheath and core structure. In this case, the first polyester forms a core component of the core-sheath type structure, and the second polyester forms a sheath component of the heart-shaped structure.

Optionally, the filaments formed by the composite radiation may have a side by side structure.

Alternatively, the filaments formed by the composite radiation may have a sea and islands structure. In this case, the first polyester forms an islands component of the sea-island structure, and the second polyester forms a sea component of the sea-island structure.

The web forming step may include a step of drawing the filaments formed by the composite yarn, carding the drawn filaments, and laminating the carded filaments.

The opening step may include discharging the drawn filaments, colliding the discharged filaments to the impingement plate, and collecting the filaments to be diffused due to collision with the impingement plate.

The foregoing general description of the present invention is intended to be illustrative of or explaining the present invention, but does not limit the scope of the present invention.

According to the production method of the present invention, since the web is formed by spinning the polyester having the low melting point of 180 to 220 DEG C with the regular polyester, the individual filaments constituting the web are formed by the polyester having the low melting point and the regular polyester . That is, only a part of the filaments are the low-melting-point polyesters. Therefore, when the thermal bonding process to the web is carried out, the low melting point copolyester can be melted with a considerably smaller amount of heat than when the entire filament is a low melting polyester.

That is, according to the present invention, the web bonding process can be carried out at a temperature of 100 ° C or lower, which is a temperature considerably lower than the melting point (180-220 ° C) of the low-melting-point polyester compounded together with the regular polyester. Therefore, not only the cost required for the thermal bonding process can be remarkably reduced as compared with the prior art, but also the failure of the device used for thermal bonding is reduced, and the maintenance and repair costs can be simultaneously reduced.

In addition, since the time required for the heat bonding step and the temperature lowering time after the heat bonding step are decreased, the entire nonwoven fabric manufacturing process can be efficiently performed.

In addition, since the thermal bonding process is performed at a relatively low temperature, the damage of the fiber due to the heat applied during the heat bonding process (precisely, the damage of the regular polyester portion in each fiber) can be minimized, Can be obtained.

Other advantages of the present invention will be described in detail below with reference to the related technical structures.

Hereinafter, a method for producing the polyester spunbonded nonwoven fabric of the present invention will be described in detail.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

As used herein, the term 'composite spinning' is a concept distinguished from 'spinning and mixing' and 'mixing and spinning', wherein ' The 'composite radiation' is a spinning method in which two or more materials that are radiated together form one filament, while the spinning is a spinning method of preparing and mixing a plurality of filaments formed of different materials by spinning, respectively. In the meantime, 'mixed spinning' is a spinning method in which two or more materials are simply mixed and spinning the mixture to form filaments, in which the arrangement of each material in the produced filament can not be controlled, .

The method for producing a polyester spunbonded nonwoven fabric of the present invention comprises a step of composite spinning a first polyester having a melting point of 240 to 270 DEG C and a second polyester having a melting point of 180 to 220 DEG C, To form a web, and thermally bonding the web at 100 DEG C or less.

The first polyester may comprise polyethylene terephthalate or polynaphthalene terephthalate.

The second polyester may include a copolymer in which the polyester of polyethylene terephthalate or polynaphthalene terephthalate is copolymerized with adipic acid or isophthalic acid. In this case, the melting point of the second polyester can be adjusted to 180 to 220 占 폚, more preferably to 190 to 215 占 폚 by controlling the amount of adipic acid or isophthalic acid added during the copolymerization process. According to an embodiment of the present invention, the amount of adipic acid or isophthalic acid added is 10 to 40 mol%.

If the melting temperature of the second polyester having a low melting point exceeds 220 ° C, there is a problem that the temperature required for thermal bonding of the web increases to 150 ° C or higher even if the web is formed by the composite spinning of the present invention.

On the other hand, when the melting temperature of the second polyester having a low melting point is less than 180 캜, it is difficult to spin the second polyester having a low melting point at a temperature higher than the melting point of the first polyester, . Despite these disadvantages, even if a nonwoven fabric is manufactured by performing the heat bonding process at a low temperature of 100 ° C or less, the shape of the nonwoven fabric may change during long-term storage in a high temperature environment.

Accordingly, the second polyester having a low melting point used in the present invention preferably has a melting point of 180 to 220 캜.

The filaments formed by the composite yarn of the present invention have a sheath and core structure, a side by side structure, or a sea and islands structure. According to the present invention, the second polyester material having a low melting point is controlled to be disposed on a portion (for example, a core component or a sea component) of a filament which can be most affected by external heat.

According to the present invention, since the second polyester having the low melting point is disposed at the outer portion of the filament which can be most affected by external heat, almost all of the second polyester can be melted through the heat bonding process . Accordingly, the amount of the second polyester among the first and second polyesters used in the composite spinning step is less than 15 to 30 wt%, which is the input amount of the low melting polyester in the conventional mixed spinning or mixed spinning, To 20% by weight. That is, the present invention can reduce the production cost and the economical efficiency of the nonwoven fabric by reducing the amount of the second polyester having a relatively low melting point, which is relatively high, without lowering the tensile strength of the nonwoven fabric.

According to an embodiment of the present invention, the web forming step may include a step of drawing filaments formed by the composite fiber, opening the drawn filaments, and laminating the opened filaments.

The opening step may include discharging the drawn filaments, colliding the discharged filaments with the impingement plate, and collecting the filaments diffused due to collision with the impingement plate on the conveyor belt . The filaments collected on the conveyor belt are laminated to form a web.

Next, the polyester spunbonded nonwoven fabric of the present invention is produced by thermally adhering the web at 100 DEG C or less.

The thermal bonding may be carried out by an embossing method or a calendering method in which the web is squeezed between the heated rollers. Alternatively, the thermal bonding may be performed by a hot air method in which hot air passes through the web. The temperature of the heat bonding process as used herein refers to the temperature of the embossing roll, the temperature of the calender roll, or the temperature of the hot air.

As described above, according to the present invention, the individual filaments formed by the composite yarn include both the first and second polyesters because the first and second polyester are co-spun. In this respect, the present invention is distinguished from the prior art in which filaments of different kinds are produced by mixed-spinning a plurality of materials, but each filament is formed of only one material.

As described above, the thermal bonding of the web composed of the filaments formed through the mixed fiber spinning of the regular polyester and the low melting point polyester is carried out at least at a relatively high temperature near the melting point of the low melting point polyester (for example, And when the melting point of the polyester is 200 DEG C, 200 DEG C or 5 DEG C). The entire filament formed only of the low-melting-point polyester must be melted through the heat-bonding step.

On the other hand, according to the composite yarn of the present invention, since only a part of each filament is the second polyester having a low melting point, the amount of the low melting point second polyester Can be melted.

In addition, according to the composite yarn of the present invention, the second polyester material having the low melting point is disposed at a portion (for example, an outer portion) of the filament which can be most affected by external heat, The second low melting point polyester can be melted with a relatively small amount of heat.

As a result, the thermal bonding to the web of the present invention consisting of filaments formed through the combined spinning of the first and second polyester is carried out at 100 DEG C or below which is significantly lower than the melting point (180-200 DEG C) of the second polyester . Therefore, not only the cost required for the thermal bonding process can be remarkably reduced as compared with the conventional technology, but also the failure of the device used for thermal bonding is reduced, and the maintenance and repair costs can be simultaneously reduced. In addition, since the time required for the heat bonding step and the temperature lowering time after the heat bonding step are decreased, the entire nonwoven fabric manufacturing process can be efficiently performed. In addition, since the thermal bonding process is performed at a relatively low temperature, the damage of the fiber due to the heat applied during the heat bonding process (precisely, the damage of the regular polyester component) can be minimized, Can be obtained.

According to an embodiment of the present invention, the filaments formed by the composite radiation may have a sheath and core structure. The first polyester forms a core component of the core-sheath type structure, and the second polyester having a low melting point forms a sheath component of the core-sheath type structure. In this embodiment, since only the supernatant corresponding to the outer portion of the filament is melted for thermal bonding of the web, the thermal bonding process can be performed at 100 ° C or less.

According to another embodiment of the present invention, the filaments formed by the composite radiation have a side by side structure. Even in this case, since only one side of the filament is melted for thermal bonding of the web, the thermal bonding process can be performed at 100 ° C or lower.

According to another embodiment of the present invention, the filaments formed by the composite fibers have a sea and islands structure. The first polyester forms an islands component of the sea-island structure, and the second polyester forms a sea component of the sea-island structure. In the case of this embodiment, since only the components of the filament are dissolved in order to thermally bond the web, the thermal bonding process can be performed at 100 ° C or lower.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. It should be noted, however, that the scope of the present invention should not be limited by the following examples.

Example  One

(IV) having an intrinsic viscosity (IV) of 0.655 and a melting point of 254 DEG C, a low-melting-point polyester having an intrinsic viscosity of 0.745 and a melting point of 214 DEG C, which were prepared by introducing adipic acid in an amount of about 19 mol% And 288 ℃, respectively, and sheath and core type composite spinning was performed. At this time, the charging amount of the low melting point polyester was 15% by weight.

The filament formed by the composite spinning was stretched and discharged through a nozzle. The discharged filament collided with the impact plate. The filaments diffused by the collision were deposited on the conveyor belt and laminated in web form. The filaments constituting the web had a line density of about 9 denier.

The nonwoven fabric was then completed by passing the web between 86 ° C embossing rollers. The pressure between the embossing rollers in the heat bonding step was 24 N / cm.

The thus-produced nonwoven fabric had a production width of 5.2 M and a surface density of 100 g / m 2.

Example  2

A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of the low-melting polyester added was 10% by weight in the composite spinning.

Example  3

A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of the low-melting polyester added was 5% by weight in the composite spinning.

Example  4

A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of the low-melting-point polyester was 20 wt% in the composite spinning.

Example  5

A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of the low-melting-point polyester added was 4% by weight in the composite spinning.

Example  6

A nonwoven fabric was produced in the same manner as in Example 1, except that the amount of the low-melting polyester added was 24% by weight in the composite spinning.

Example  7

A nonwoven fabric was produced in the same manner as in Example 1, except that side-by-side composite spinning was performed in place of the core-sheath type composite spinning, and the amount of the low-melting-point polyester was 20 wt% .

Example  8

A nonwoven fabric was prepared in the same manner as in Example 1, except that the sea-island composite yarns (number of islands: 12) were used instead of the core-sheath type composite yarns and the amount of the low-melting polyester added was 20 wt% .

Example  9

Except that a low melting point polyester having a melting point of 210 DEG C was used in place of the low melting point polyester having a melting point of 214 DEG C and the heat bonding temperature (temperature of the embossing roller) was 82 DEG C Nonwoven fabric was produced.

Example  10

Except that a low melting point polyester having a melting point of 195 DEG C was used in place of the low melting point polyester having a melting point of 214 DEG C and the heat bonding temperature (temperature of the embossing roller) was 63 DEG C Nonwoven fabric was produced.

Example  11

Except that a low melting point polyester having a melting point of 180 캜 was used in place of the low melting point polyester having a melting point of 214 캜 and the temperature of heat bonding (temperature of the embossing roller) was 55 캜 Nonwoven fabric was produced.

Example  12

Melting polyester having a melting point of 215 캜 (a mixture of adipic acid and isophthalic acid was used for copolymerization with polyester, and the weight ratio thereof was 50:50) was used instead of the low melting polyester having a melting point of 214 캜 , And a nonwoven fabric was produced in the same manner as in Example 1, except that the heat bonding temperature (temperature of the embossing roller) was 88 ° C.

Comparative Example  One

Example 1 and Example 2 were repeated except that the low melting point polyester was not used and only the normal polyester was spun alone and the heat bonding temperature (temperature of the embossing roller) was 252 DEG C and the pressure between the embossing rollers was 44 N / cm. A nonwoven fabric was produced in the same manner.

Comparative Example  2

A nonwoven fabric was prepared in the same manner as in Example 1, except that the mixed yarn was subjected to the mixed yarn spinning, the heat bonding temperature (temperature of the embossing roller) was 212 DEG C, and the pressure between the embossing rollers was 34 N / cm .

Comparative Example  3

The composite spinning was carried out in the same manner as in Example 1, except that a low melting point polyester having a melting point of 175 캜 was used in place of the low melting point polyester having a melting point of 214 캜. However, I could not.

Comparative Example  4

Except that a low melting point polyester having a melting point of 224 DEG C was used in place of the low melting point polyester having a melting point of 214 DEG C and the heat bonding temperature (temperature of the embossing roller) was 160 DEG C Nonwoven fabric was produced.

The tensile strength, elongation, and tear strength of the nonwoven fabric produced by the above-described Examples and Comparative Examples were measured according to JIS L 1906, which is a long fiber spunbond nonwoven fabric measuring method, and the results are shown in Table 1 below Respectively.

Low melting point
PE
input
(weight%) radiation
Way Low melting point
PE
Melting point
(° C) Thermal bonding
Temperature
(° C) Thermal bonding
pressure
(N / cm) The tensile strength
(Kg / 5 cm) Shindo
(%) Phosphorus strength
(kgf) MD CD MD CD MD CD Example 1 15 Heart-shaped
Composite radiation 214 86 24 38 36 43 48 8.8 9.3 Example 2 10 Heart-shaped
Composite radiation 214 86 24 34 35 40 45 9.3 8.8 Example 3 5 Heart-shaped
Composite radiation 214 86 24 32 30 38 42 8.2 8.5 Example 4 20 Heart-shaped
Composite radiation 214 86 24 37 36 45 46 8.4 8.2 Example 5 4 Heart-shaped
Composite radiation 214 86 24 24 22 23 28 4.9 5.5 Example 6 24 Heart-shaped
Composite radiation 214 86 24 35 33 45 44 7.1 7.3 Example 7 20 side by side
Composite radiation 214 86 24 32 33 41 40 8.1 8.5 Example 8 20 Sea chart type
Composite radiation
(12 degrees) 214 86 26 38 37 45 46 8.4 8.2 Example 9 15 Heart-shaped
Composite radiation 210 82 24 36 37 44 43 8.3 8.2 Example 10 15 Heart-shaped
Composite radiation 195 63 24 37 38 47 43 8.9 8.6 Example 11 15 Heart-shaped
Composite radiation 180 55 24 36 34 48 45 8.6 8.7 Example 12 15 Heart-shaped
Composite radiation 215 88 24 34 36 43 42 8.5 8.4 Comparative Example 1 0 Singlet radiation - 252 44 20 18 18 22 2.4 3.6 Comparative Example 2 15 Mixed radiation 214 212 34 26 24 23 22 2.8 2.7 Comparative Example 3 15 Heart-shaped
Composite radiation 175 Non-woven fabrication impossible due to cutting Comparative Example 4 15 Heart-shaped
Composite radiation 224 160 24 32 27 35 37 5.7 5.9

(* Note: MD: Mechanical Direction, CD: Cross Direction)

Claims (8)

A first polyester having a melting point of 240 to 270 캜 and a second polyester having a melting point of 180 to 220 캜;
Forming a web with filaments formed by the composite radiation; And
Thermally bonding the web at a temperature less than 100 < 0 > C,
Wherein the second polyester is a copolyester made from copolymerized monomers comprising adipic acid, isophthalic acid, or mixtures thereof,
Wherein the content of the adipic acid or the isophthalic acid in the second polyester is 10 to 40 mol%. delete The method according to claim 1,
Wherein the amount of the second polyester among the first and second polyesters used in the composite spinning step is 5 to 20 wt%. The method according to claim 1,
The filaments formed by the composite radiation have a sheath and core structure,
Wherein the first polyester forms a core component of the heart-shaped structure,
Wherein said second polyester forms a sheath component of said core-sheath type structure. ≪ Desc / Clms Page number 20 > The method according to claim 1,
Wherein the filaments formed by the composite yarn have a side by side structure. The method according to claim 1,
The filaments formed by the composite radiation have a sea and islands structure,
The first polyester forms an islands component of the sea-island structure,
Wherein the second polyester forms a sea component of the sea-island structure. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
The web forming step may include:
Stretching the filaments formed by the composite spinning;
Opening the elongated filaments; And
And laminating the carded filaments. ≪ RTI ID = 0.0 > 11. < / RTI > 8. The method of claim 7,
In the opening step,
Discharging the drawn filaments;
Colliding the discharged filaments with the impingement plate; And
And collecting the filaments diffused due to the collision with the impingement plate. ≪ RTI ID = 0.0 > 11. < / RTI >