KR20170001319A - Dimensional Stable Non-woven Fabric, and Method for Manufacturing the Same - Google Patents

Abstract

The present invention relates to a non-woven fabric capable of stably maintaining a shape at a high temperature and a method for producing the same. According to the present invention, the non-woven fabric minimizes the content of low melting point polyester to which high melting point polyester fiber is bonded and prevents the non-woven fabric from being shrunk by heat in advance at a temperature higher than a hot air hardening temperature of a carpet manufacturing process. The carpet can be prevented from twisting and curling due to the hot air curing of the carpet, and the non-woven fabric having the shrinkage ratio of 0% is produced through a heat fixing step. Therefore, the non-woven fabric is particularly suitable for a tile carpet foil. Since the shrinkage of the non-woven fabric is prevented, it is possible to simplify the manufacturing process and reduce the manufacturing costs by eliminating the use of a secondary foam sheet that compensates for the shrinkage ratio.

Description

Technical Field [0001] The present invention relates to a non-woven fabric having improved shape stability and a method for manufacturing the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric capable of stably maintaining a shape at a high temperature and a method for producing the same.

The carpet has excellent walking feeling and sound absorbing property, so it feels less fatigue than other materials and enables a quiet living environment. Also, it prevents the risk of falling because it does not slip and maintains a constant temperature of heating and cooling due to low thermal conductivity It is a high-quality flooring material that provides a pleasant environment compared to plastic or wood flooring because it absorbs less amount of heat and adsorbs dust in the air.

Carpets can be divided into roll carpets and tile carpets depending on the shape. The roll carpet is relatively thick and the pile yarn is abundant, so it is possible to produce a luxurious atmosphere and it has a good cushion feeling. It has various patterns and colors, It is used in a wide range of places, such as hotels and banquet rooms, which need a luxurious interior effect, but it is difficult to manage and store.

The tile carpet is divided into a tile-like small carpet, and then it is separated from the wide, rectangular, roll-type carpet without any joints. It can be vacuumed and steamed to facilitate maintenance and management. If the carpet is contaminated, it can be partially replaced and repaired. This reduces the economic burden and troubles of replacing the entire carpet. It is easy to roll the chair wheel because the thickness is thin and the file is not abundant. It is growing steadily every year.

Tile carpets are used in tufting processes and in back coating processes such as polyvinyl chloride (PVC), ethylene vinyl acetate (EVA) or styrene butadiene rubber (PVC) on the back of tufted nonwovens (SBR), and then curing], and then cut into a square (50 x 50 cm) shape to produce a final product.

The tile carpet is composed of carpet yarn, primary primer, primary and secondary coating liquid, and secondary primer. The carpet yarn is used to provide sound absorption and cushioning as a part exposed on the surface. The primary coating serves as an adhesive to prevent the carpet from falling out of the primary support, and the secondary coating provides the elasticity and weight of the carpet (to keep it on the floor). And the secondary foam stabilizes the shape of the carpet by compensating for the difference in shrinkage ratio between the two coating liquids.

However, the tile carpet of this structure uses various materials such as fiber (carpet yarn), nonwoven fabric (primary geforge), PVC / EVA / SBR (coating liquid) , Which causes different shrinkage ratios in the process of curing by hot air during the carpet manufacturing process, so that the edge of the final product of the tile carpet tends to float (curl) or warp the entire shape.

In addition, since the tile carpet is constructed by connecting several pieces of the carpet, there is no gap in the joint portion, and therefore, the shape stability is more important among various physical properties required for the carpet.

In order to solve the above problems, the present inventors have found that a polyester having an intrinsic viscosity of 0.655, a melting point of 250 to 270 ° C, an intrinsic viscosity of 0.620 to 0.745 and a melting point of 180 to 226 ° C 20% by weight of an encopolyester, and Korean Patent Laid-Open Publication No. 2014-0119351 discloses a high-melting-point polyester having a melting point of 250 to 270 DEG C and a high- A low melting point copolymer in a ratio of 90 to 96: 4 to 10% by weight to form a web with a filament formed thereon, followed by thermal bonding to produce a spunbonded nonwoven fabric for carpet bubbles.

The above-mentioned inventions attempted to suppress the distortion of the carpet and the curling of the carpet in the hot air curing process of the carpet manufacturing process by lowering the heat shrinkage rate of the spunbond nonwoven fabric by controlling the intrinsic viscosity, melting point, and content of the low melting point copolymer to a specific range .

However, in the hot air condition used in the process of curing the coating liquid during the carpet manufacturing process, the high melting point polyester has no shape deformation, while the low melting point copolyester has the low melting point and is in a state immediately before melting, which causes shrinkage and relaxation of the spunbond non- The same deformation is likely to occur. In addition, since the above-mentioned invention is produced by the complex spinning method in which a low melting point copolyester is contained in a large amount or a low melting point copolymer is placed on the surface, the low melting point copolymer The shape modification of the nonwoven fabric occurs in the back coating process.

Accordingly, the nonwoven fabric used as the base fabric of the carpet is required not only to have properties such as strength and elongation but also to ensure that the form can be stably maintained even in a high temperature heat treatment process during the carpet manufacturing process.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a nonwoven fabric capable of stably forming a nonwoven fabric in a process requiring high temperature coating and hot air- And a method for producing the same.

In order to solve the above problems, the present invention provides a nonwoven fabric comprising 90 to 95% by weight of a high-melting-point polyester fiber having a melting point of 255 ° C or higher and 5 to 10% by weight of a low- The tensile strength in the CD direction is 16 to 22/17 to 23 kgf / 5 cm and the tensile elongation in the MD direction / CD direction is 30 to 34/31 to 37%.

The present invention also provides a method for producing a polyester resin composition, comprising the steps of: 90 to 95% by weight of a high-melting-point polyester having a melting point of 255 ° C or higher; and 5 to 10% by weight of a low-melting-point polyester having a melting point of 180 ° C or higher; Laminating the web of the mixed fiber; Thermally fusing the web; And thermally fixing the thermally fused web at 200 to 220 ° C. The present invention also provides a method for producing a nonwoven fabric having improved morphology stability.

The monofilament fineness of the high-melting-point polyester fiber is preferably 1 to 5 denier, and it is preferable that the monofilament fineness of the low melting point polyester is 180 to 210 ° C at 180 ° C or less.

The high melting point polyester is preferably polyethylene terephthalate, polybutylene terephthalate or poly naphthalene terephthalate, and the low melting point polyester may be obtained by copolymerizing adipic acid, isophthalic acid, Is more preferable.

The degree of fineness of the cross-linked mixed yarn is preferably 4 to 10 denier, and it is preferable that the heat fusion is fused at a temperature within a range not exceeding 10 占 폚 of a melting point of the low melting point polyester.

The nonwoven fabric of the present invention minimizes the content of the low melting point polyester to which the high melting point polyester fiber is bonded and prevents the nonwoven fabric from being shrunk by heat in advance at a temperature higher than the hot air hardening temperature of the carpet manufacturing process, It is possible to prevent the carpet from twisting and curling due to the hot air curing of the carpet.

In addition, since the low melting point polyester fibers that have been mixed and spinned are melted to bond and fix the high melting point polyester fibers, the nonwoven fabric constituting the nonwoven fabric It is possible to lower the content of the low melting point polyester because the needle hole is formed smaller than the composite spinning nonwoven fabric having a large needle hole after the tufting process because of high fluidity of the filament, Heat shrinkage due to the polyester can be prevented.

In addition, since the nonwoven fabric having the shrinkage ratio of 0% is produced through the heat fixing step, the nonwoven fabric is particularly suitable for the bubble paper of the tile-type carpet requiring shape stability, and the secondary bubble paper There is an advantage that the manufacturing process can be simplified and the manufacturing cost can be lowered.

During the manufacturing process of the carpet, the carpet yarn is passed through the nonwoven fabric in a vertical direction using a needle, and subjected to a tufting process of binding and transplanting. The tufted carpet is coated with a coating solution at high temperature for fixing and durability Heat treatment and drying process inevitably result in deformation due to heat shrinkage of the substrate.

In order to solve such a problem, in the present invention, two kinds of polyester compositions composed of 90 to 95% by weight of a high melting point polyester having a melting point of 255 캜 or higher and 5 to 10% by weight of a low melting point polyester having a melting point of 180 캜 or higher, the web is laminated and thermally fused to form a matrix & binder, and then heat-set at a temperature higher than a general curing temperature of the carpet manufacturing process of 160 to 180 ° C to produce a nonwoven fabric, Thereby preventing the nonwoven fabric from being thermally shrunk.

In general, the coating temperature of the carpet, the heat treatment, and the drying temperature are about 180 ° C. Therefore, in order to produce the nonwoven fabric having excellent shape stability according to the present invention, it is necessary to maintain the melting temperature of the low melting point polyester contained in the nonwoven fabric at 180 ° C. or more.

If the melting point of the low melting point polyester is lower than 180 캜, the low melting point polyester is redissolved during the carpet manufacturing process, the breakage of the foam sheet tends to occur, and the heat shrinkage rate is also increased. As a result, the width and length of the carpet finished product become insufficient. The shape of the carpet is distorted due to the difference in the heat shrinkage rate of the coating material, or the edge of the carpet is curled up at the sides.

When the melting temperature is 210 ° C or higher, the heat shrinkage rate of the nonwoven fabric is stabilized and the sheet is not deformed during the carpet manufacturing process. However, the high temperature coating, heat treatment and drying process The flexibility of the nonwoven fabric is lowered and the difference in the fine elongation between the nonwoven fabric and the coating solution coated on the lower end of the nonwoven fabric appears.

These minute differences are not a problem in the products immediately after the production, but as the use period of the carpet is increased, latent stress due to difference in elongation between the coating material and the nonwoven fabric may cause deformation of the carpet.

In general, when producing a polyester nonwoven fabric, in order to obtain excellent physical properties, the content of the low melting point resin used for the heat adhesive is used in excess of 10% by weight and further increased to 15% by weight or more. The heat shrinkage rate of the nonwoven fabric is increased due to excessive content of the adhesive component in the nonwoven fabric, so that the shape stability of the carpet manufacturing process is lowered and the high melting point polyester fibers are closely adhered to each other, The polyester fibers are damaged by the penetration of the needles in the tufting step of the carpet, so that the tensile strength of the carpet is lowered.

In order to solve this problem, in the present invention, the low melting point polyester is contained in an amount of 5 to 10% by weight of the nonwoven fabric so that the adhesion point between the high melting point polyester fibers is maintained at a certain level or less to prevent damage to the fiber, In the heat treatment and drying process, appropriate flexibility is imparted to the nonwoven fabric to improve the shape stability of the final product carpet.

When the content of the low melting point polyester is as low as 10% by weight or less, the tensile strength of the nonwoven fabric itself falls, but the tensile strength retention after tufting becomes excellent. More specifically, The tensile strength of the nonwoven fabric is lowered. However, when the needles penetrate the nonwoven fabric during the tufting, the bonding force between the fibers is low, so that damage of the fibers by the needles can be avoided.

Therefore, the tensile strength of the nonwoven fabric after tufting is higher than that of the nonwoven fabric produced with a low-melting-point polyester content exceeding 10% by weight, and as a result, a carpet having excellent strength can be produced. Usually, the low- Because it is expensive, it is advantageous in terms of manufacturing cost as it is used less.

In addition, the low melting point polyester causes heat shrinkage of the nonwoven fabric, and the effect of preventing the heat shrinkage of the nonwoven fabric can be obtained by maintaining the low melting point polyester content at 10 wt% or less as in the present invention

However, when the content of the low melting point polyester is further reduced to less than 5% by weight, portions not bonded to each other between the high melting point polyester fibers are increased, so that the shape of the nonwoven fabric may not be well formed, It is too low to be able to handle the tensile force in the tufting, coating, heat treatment and drying processes, and may break.

The high melting point polyester of the present invention is not limited to a polyester resin having a melting point of 255 DEG C or higher, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, poly naphthalene terephthalate polynaphthalene terephthalate) and the like.

The low melting point polyester is obtained by mixing additives such as adipic acid or isophthalic acid in the polyester of the same kind as the high melting point polyester material in the polymerization process and adjusting the melting point to 180 ° C or higher It is preferable that the low melting point polyester is melted in the heat welding step so that the high melting polyester can be easily bonded to the high melting point polyester in the process of bonding the high melting point polyester fibers to each other, It is also effective in lowering the shrinkage rate.

The high melting point polyester and the low melting point polyester are fed to an extruder and mixed and dispersed through different discharging holes of a spinneret, laminated on the web, heat-sealed and heat set to produce a nonwoven fabric.

At this time, the filament was sufficiently stretched at a spinning speed of 4500 to 5000 m / min using a high-pressure air stretching device to form a high-melting-point polyester and a low-melting-point polyester into monofilaments of 1 to 5 denier These fibers can be mixed to produce a hornblende yarn having a fineness of 4 to 10 denier. The blend of the high-melting-point polyester fiber and the low-melting-point polyester fiber can be used for both the blending and the blending.

When the high-melting-point polyester and the low-melting-point polyester are co-spun, the low-melting-point polyester is exposed on the surface of the composite yarn so that the low-melting-point polyester is melted and the composite yarn is shrunk. Melt spinning polyester fiber and low melting point polyester fiber, respectively, and melting the low-melting-point polyester fiber to adhere the high-melting-point polyester fiber, so that heat shrinkage of the nonwoven fabric can be prevented.

The heat fusion may be carried out by hot air at a temperature equal to or higher than the melting point of the low melting point polyester, preferably at a temperature within a range not exceeding the melting point of the low melting point polyester and not exceeding 10 占 폚, Is more preferable.

If the heat-setting temperature is lower than 200 ° C, the heat-setting temperature is lowered to 200 to 220 ° C, which is higher than the normal curing temperature of the carpet manufacturing process. The strength of the nonwoven fabric is excessively increased, and the resistance of the nonwoven fabric to the penetration of the needle is increased in the tufting step in which the needle passes through the nonwoven fabric while the carpet yarn is being planted, which is disadvantageous in that the tufting operation is disadvantageous .

The nonwoven fabric of the present invention manufactured as described above is free from heat shrinkage and is free from curling of the edges and can eliminate secondary foams for supplementing shrinkage of the coating liquid and is excellent in tensile strength and flexibility and tile- It is particularly suitable for use in carpets.

Hereinafter, the present invention will be described in more detail with reference to the following examples, comparative examples and test examples.

It is to be understood, however, that the invention is not to be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Will be apparent to those skilled in the art to which the present invention pertains.

<Examples 1 to 4> and <Comparative Examples 1 to 4>

Polyethyleneterephthalate having a melting point of 255 占 폚 and adipic acid as a second filament were added as a first filament and polyethylene terephthalate having a melting point of 180 占 폚 was melted at a spinning temperature of 288 占 폚 using a continuous extruder, And the content ratio of the second filaments was subjected to a mixed fiber spinning at the composition ratio shown in Table 1 below.

Then, the continuous filaments discharged from the capillary were solidified by cooling wind and stretched to a spinning speed of 5000 m / min using a high-pressure air stretching device to produce a filament yarn of a fineness of 9 denier.

The produced horny filament yarn was laminated in the form of a web on a conveyor net by a conventional filament method and then subjected to a calendering process using a heated calender roll to impart smoothness and appropriate thickness.

The laminated horn sheathed yarn was thermally adhered by hot air at 180 캜, which is the same temperature as the second filament melting point. The laminated horn filament yarn was heat-set in a tenter operated at the temperature shown in Table 1 below and then coated with a small amount of emulsion, 90 g / m &lt; 2 &gt;.

Production conditions of nonwoven fabric The first filament melting point
(° C) Second filament melting point
(° C) The first filament /
The second filament content ratio
(weight%) Heat setting temperature
(° C) Example 1 255 180 95/5 200 Example 2 255 180 93/7 200 Example 3 255 180 90/10 200 Example 4 255 180 93/7 220 Comparative Example 1 255 180 96/4 200 Comparative Example 2 255 180 88/12 200 Comparative Example 3 255 180 93/7 195 Comparative Example 4 255 180 93/7 225

<Test example> Measurement of physical properties

The properties of the nonwoven fabric of the examples and comparative examples prepared above were measured and are shown in Table 2 below.

Tensile strength and tensile elongation were measured by using KS K 0521 method. Specifically, nonwoven fabric specimens of 5 × 20 cm in length × 5 cm were bite with a jig with 5 × 5 ㎝ in size by using INSTRON measuring equipment, 200 mm / min.

Heat shrinkage was measured on a 20 × 20 ㎝ square (MD / CD direction notation) on a nonwoven fabric specimen of 25 × 25 ㎝ in width × length, and preheated for 3 minutes in a hot air drier operated at 180 ° C. × 20 ㎝ square.

The coating liquid (polyvinyl chloride) was applied on the back surface of the nonwoven fabric to a thickness of 2 mm and cured in a hot-air drier operated at 180 ° C for 3 minutes. The specimens were cut to a size of 20 × 20 cm. , The distance between the edge of the quadrangle and the bottom (height of the specimen edge on the floor) was measured with a thickness gauge, and the average of the maximum values of the measured values was calculated to calculate the curl height after coating Respectively.

Results of measurement of physical properties of nonwoven fabric The tensile strength
(MD / CD ^{Note 1)} )
(kgf / 5 cm) Tensile elongation
(MD / CD)
(%) Heat shrinkage
(MD / CD)
(%) After coating
Curling Height
(mm) Final Evaluation ^{Note 2 )} Example 1 16.8 / 17.5 30.1 / 31.0 0.0 / 0.0 0.0 ○ Example 2 18.4 / 19.2 32.8 / 36.7 0.0 / 0.0 0.0 ◎ Example 3 21.3 / 22.9 33.5 / 32.6 0.0 / 0.0 0.0 ○ Example 4 20.6 / 22.7 31.4 / 34.8 0.0 / 0.0 0.0 ○ Comparative Example 1 13.4 / 14.9 19.2 / 21.2 0.1 / 0.0 0.0 △ Comparative Example 2 22.4 / 24.1 33.8 / 34.9 0.2 / 0.1 0.2 × Comparative Example 3 16.1 / 16.5 29.8 / 30.6 0.3 / 0.1 0.5 × Comparative Example 4 25.4 / 27.6 36.8 / 39.2 0.0 / 0.0 0.0 △ Note 1) MD / CD (MD: mechanical direction, CD: cross direction)
Note 2)?: Very excellent,?: Excellent,?: Fair, X: poor

From the results of Table 2, the nonwoven fabric of the examples exhibited uniform properties in the evaluation of tensile strength, tensile elongation, heat shrinkage and edge curl after coating.

In more detail, the tensile strength of the nonwoven fabric was the highest in Comparative Example 4, in which the heat fixing temperature was the highest at 225 ° C, and Comparative Example 2, which contained the highest amount of low melting point polyester in 12% by weight, Comparative Example 1 having the lowest melting point polyester content of 4 wt% was the lowest and Comparative Example 3 having the lowest heat setting temperature of 195 DEG C was the next lowest measured.

That is, it can be confirmed that the tensile strength becomes higher as the heat fixing temperature is higher and as the content of the low melting polyester is increased, the amount of the low melting polyester binding the high melting polyester fibers of the nonwoven fabric is increased, It can be seen that the tensile strength of the nonwoven fabric can be increased.

Tensile elongation also showed a trend similar to that of tensile strength, indicating that it is dependent on the low melting point polyester content and the heat setting temperature.

The heat shrinkage rate was as high as 0.3 / 0.1 in Comparative Example 3 where the heat fixing temperature was the lowest at 195 deg. C, and thus, the highest curling height after coating was 0.5 mm, and the lowest melting polyester was 12 weight% The heat shrinkage ratio and the curling height after coating of Comparative Example 2 were found to be as follows.

That is, the lower the heat fixing temperature and the higher the content of the low melting point polyester, the greater the heat shrinkage ratio of the nonwoven fabric. Thus, when the coating liquid is applied to the back surface of the nonwoven fabric and cured, .

On the other hand, in the example according to the present invention and the comparative example 4, heat shrinkage and curling were not shown. This is because the low melting polyester content of the nonwoven fabric is limited to 5 to 10% It is judged that the carpet can be prevented from twisting and curling in the hot air curing step of the carpet manufacturing process by preheating at a temperature of 200 DEG C or higher.

However, in order to prevent heat shrinkage and curling, if the content of the low-melting-point polyester is too low as in Comparative Example 1, the adhesive strength of the high-melting-point polyester fiber is lowered and the tensile strength and tensile elongation are lowered, As shown in Example 4, if the heat fixing temperature is too high, the nonwoven fabric becomes too hard to have low flexibility, which is not suitable as a nonwoven fabric for carpet bubbles.

As described above, the nonwoven fabric of the present invention has excellent strength properties and does not undergo heat shrinkage at high temperatures so that the curling of the sides can be avoided, and it is possible to produce high quality carpets with improved morphological stability by having moderate elongation under a given tensile force .

Claims (11)

A nonwoven fabric comprising 90 to 95% by weight of a high-melting-point polyester fiber having a melting point of 255 DEG C or higher and 5 to 10% by weight of a low-melting-point polyester having a melting point of 180 DEG C or higher,
Wherein the tensile strength in the MD direction / CD direction is 16 to 22/17 to 23 kgf / 5 cm and the tensile elongation in the MD direction / CD direction is 30 to 34/31 to 37%. The method according to claim 1,
Wherein the monofilament fineness of the high melting point polyester fiber is 1 to 5 denier and the form stability is improved without changing the shape by heat at a temperature of 180 DEG C or less. The method according to claim 1,
Wherein the low melting point polyester has a melting point of 180 to 210 占 폚. The method according to claim 1,
Wherein the high melting point polyester is polyethylene terephthalate, polybutylene terephthalate or polynaphthalene terephthalate. The method of claim 4,
Wherein the low melting point polyester is characterized in that adipic acid, isophthalic acid or both of them are copolymerized with the high melting point polyester. 90 to 95% by weight of a high-melting-point polyester having a melting point of 255 캜 or higher and 5 to 10% by weight of a low-melting-point polyester having a melting point of 180 캜 or higher;
Laminating the web of the mixed fiber;
Thermally fusing the web; And
And thermally fixing the thermally fused web at 200 to 220 ° C. The method of claim 6,
Wherein the low-melting-point polyester has a melting point of 180 to 210 占 폚. The method of claim 6,
Wherein the high melting point polyester is polyethylene terephthalate, polybutylene terephthalate or polynaphthalene terephthalate. The method of claim 8,
Wherein the low-melting-point polyester is characterized in that adipic acid, isophthalic acid or both of them are copolymerized with the high melting point polyester. The method of claim 6,
Wherein the fineness of the mixed-mixed yarn is 4 to 10 denier. The method of claim 6,
Wherein the thermal fusion is fused at a temperature within a range not exceeding a melting point of a low melting point polyester of not lower than 10 占 폚.