JP2023554424A - Non-woven fabrics, carpets and their manufacturing methods - Google Patents

Abstract

The present invention relates to a nonwoven fabric, a carpet, and a method for manufacturing the same. According to the present invention, it is possible to provide a nonwoven fabric, a carpet, and a method for producing the same, which have improved curling problems and have excellent shape stability. Further, the present invention can provide a nonwoven fabric whose shape stability can be quantitatively evaluated and predicted, and a method for manufacturing the same.

Description

[Cross reference to related applications]
This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0187593 dated December 30, 2020, and all contents disclosed in the documents of the Korean patent application are incorporated herein by reference. included as a part.

The present invention relates to a nonwoven fabric, a carpet, and a method for manufacturing the same. Specifically, the present invention relates to spunbond nonwoven fabrics, carpets, and methods of manufacturing the same.

Carpets are manufactured through a tufting process in which carpet yarns (BCF yarn) are injected into cellular nonwoven fabric. And the external forces (eg physical pressure or heat) that non-woven fabrics (cellular paper) and carpets are subjected to during the manufacturing process are considerable.

For example, external forces such as heat, tensile force, and cooling are applied at the step of manufacturing yarn in the nonwoven fabric manufacturing process, and high temperatures and pressure are required to bond the nonwoven fabric web (for example, fix the web form). In addition, in the tufting process, needles create holes in the nonwoven fabric, causing damage, and in the back coating process, heating and cooling are required.

Such a manufacturing process imparts latent stress to the nonwoven fabric and carpet, reducing the morphological stability and mechanical properties of the nonwoven fabric and carpet.

An object of the present invention is to provide a nonwoven fabric and a method for manufacturing the same.

Another object of the present invention is to provide a nonwoven fabric with improved shape stability and a method for producing the same.

Still another object of the present invention is to provide a nonwoven fabric with excellent mechanical properties and a method for producing the same.

Still another object of the present invention is to provide a nonwoven fabric whose shape stability can be quantitatively evaluated and predicted.

Still another object of the present invention is to provide a method for manufacturing a nonwoven fabric that can quantitatively evaluate and predict the morphological stability of the nonwoven fabric, so as to adjust and evaluate (or confirm) the latent stress index of the nonwoven fabric during the manufacturing process. There is a particular thing.

Still another object of the present invention is to provide a nonwoven fabric and a carpet containing the same.

The above objects and other objects of the invention can all be solved by the invention as described in detail below.

In one example according to the invention, the invention relates to a method of manufacturing a nonwoven fabric. Specifically, the method relates to a method of producing a long fiber spunbond nonwoven fabric.

According to the invention, the method includes the steps of bonding the webs (eg fixing the web form) and applying heat to relieve potential stresses after applying the oil. More specifically, the method comprises:
A first step of producing a web by melt spinning a high melting point polyester having a melting point T _{H and a low melting point polyester having a melting point T L lower} than the melting point T _H ;
a second step of joining the webs;
a third step of applying an oil to the bonded web;
and a fourth step of applying heat so that the latent stress index of the nonwoven fabric to which the oil agent has been applied is 5.00 or less. The method can effectively reduce the latent stress remaining in the nonwoven fabric.

As a result of experimental confirmation, when the weight of the nonwoven fabric is low, the stress value tends to be relatively low, and when the weight of the nonwoven fabric is high, the stress value tends to be high. However, just because the stress is relatively low does not necessarily mean that the degree of curling is low. Therefore, it is important to consider both the weight (basis) and stress value that affect the morphological stability of nonwoven fabrics to predict the degree of curling in the final carpet product at the manufacturing stage of nonwoven fabrics and to reduce the occurrence of curling. It is significant to

As a result of intensive research, the present inventor found that when heat is applied to a nonwoven fabric to which an oil agent has been applied so that the latent stress index is adjusted to 5.00 or less, the mechanical properties of the nonwoven fabric and the carpet made from it (and the uniformity of The present invention was completed by confirming that it is possible to simultaneously ensure stability) and morphological stability.

The latent stress index is the stress of the nonwoven fabric, measured according to DIN 53369, divided by the unit weight of the nonwoven fabric (g/m ² ), as described below in the experimental examples. Specifically, the latent stress index is the cooling stress (cooling stress) measured after exposing the nonwoven fabric at a temperature of 180° C. within 5 minutes according to DIN 53369 and cooling the nonwoven fabric to room temperature for about 1 minute. cN) divided by the unit weight (g/m ² ) of the nonwoven fabric, and is treated as a dimensionless constant. In some cases, stress (thermal stress) can be measured during heat treatment of the nonwoven fabric. At this time, the exposure time of the nonwoven fabric to 180° C. heat may be within 4 minutes, within 3 minutes, or within 2 minutes.

Thus, the method of the present invention includes the step of adjusting the latent stress index of the nonwoven fabric during the manufacturing process of the nonwoven fabric, thereby numerically evaluating (or confirming) the latent stress of the nonwoven fabric in this step. Processes that can improve morphological stability can be quantitatively evaluated and performed. Therefore, it is also possible to quantitatively predict and evaluate the morphological stability of the nonwoven fabric.

On the other hand, when the articles mentioned herein, their properties and process conditions for manufacturing the articles are affected by heat or temperature, unless otherwise specified, said heat or temperature is normal temperature. could be. At this time, "normal temperature" particularly means a temperature in a state where the temperature is not reduced or heated, and for example, a temperature within the range of 15 to 30°C.

Hereinafter, each step regarding the manufacturing method of the present invention will be explained in detail.

The method includes a first step of melt spinning a high melting point polyester having a melting point T _H and a low melting point polyester having a melting point T _L lower than the melting point T _H to produce a web.

The form of the web is not particularly limited. For example, the web may be in isotropic or anisotropic form.

As an example, the method can produce a web comprising 80-92% by weight of high-melting point polyester yarns and 8-20% by weight of low-melting point polyester yarns. At this time, the term "thread" can be used interchangeably with the term filament.

Specifically, the lower limit of the content of the low melting point polyester yarn is, for example, 8.5% by weight or more, 9.0% by weight or more, 9.5% by weight or more, 10.0% by weight or more, 10.5% by weight or more. weight% or more, 11.0 weight% or more, 11.5 weight% or more, 12.0 weight% or more, 12.5 weight% or more, 13.0 weight% or more, 13.5 weight% or more, 14.0 weight% % or more, 14.5% by weight or more, 15.0% by weight or more, 15.5% by weight or more, 16.0% by weight or more, 16.5% by weight or more, 17.0% by weight or more, 17.5% by weight or more than 18.0% by weight. The upper limit of the content of the low melting point polyester yarn is, for example, 19.5% by weight or less, 19.0% by weight or less, 18.5% by weight or less, 18.0% by weight or less, 17.5% by weight or less. , 17.0% by weight or less, 16.5% by weight or less, 16.0% by weight or less, 15.5% by weight or less, 15.0% by weight or less, 14.5% by weight or less, 14.0% by weight or less, 13.5% by weight or less, 13.0% by weight or less, 12.5% by weight or less, 12.0% by weight or less, 11.5% by weight or less, 11.0% by weight or less, 10.5% by weight or less, or It can be up to 10.0% by weight. If the content of the low melting point polyester that functions as a thermal adhesive is less than the above range, the thermal adhesive effect will not be sufficient. When the content of the low melting point polyester exceeds the above range, the degree of contact between the fibers increases and the movement between the fibers is restricted. Therefore, when the needle penetrates the nonwoven fabric (or cellular paper) during the tufting process, the fibers are severely damaged and the tensile strength properties of the nonwoven fabric are reduced.

As an example, according to the method, a web containing the high melting point polyester yarn having a softness of 7.0 to 10.0 deniers can be produced. If the fineness of the high melting point polyester yarn is less than the above range, the filaments are thin and the number of filaments per unit area is large, resulting in filament breakage during the tufting process, resulting in poor product quality (e.g. uniformity). do. In addition, if the fineness of the high melting point polyester yarn exceeds the above range, it is difficult to manufacture a product with a uniform shape due to insufficient cooling of the filament, and the height of the BCF yarn is uniform during the tufting process. Sexuality decreases.

As an example, according to the method, a web containing the low melting point polyester yarn having a softness of 2.0 to 5.0 denier can be produced. If the purity of the low melting point polyester yarn is less than the above range, the spinnability is poor, and if it exceeds the above range, the product quality (e.g. uniformity) may be affected due to the bundle phenomenon in which filaments adhere to each other. descend.

As an example, according to the method, a web containing the high melting point polyester yarn having a softness of 7.0 to 10.0 denier and the low melting point polyester yarn having a softness of 2.0 to 5.0 denier is produced. can do.

The above-mentioned greenness can be ensured by adjusting, for example, the spinning diameter of the spinneret used during spinning and the discharge amount during spinning.

As an example, according to the method, the ratio (N ₁ /N ₂ ) of the number N ₁ of the high melting point polyester yarns (number of filaments) to the number N ₂ of the low melting point polyester yarns is 2.0 to 5.0. It is possible to produce webs in the range of . Specifically, the lower limit of the ratio (N ₁ /N ₂ ) is, for example, 2.1 or more, 2.2 or more, 2.3 or more, 2.4 or more, or 2.5 or more, and the upper limit is For example, it can be 4.5 or less, 4.0 or less, 3.5 or less, or 3.0 or less. When the ratio exceeds the above range, that is, when the high melting point component is excessively larger than the low melting point component, bonding points between the filaments are insufficient, making it difficult to provide sufficient strength. On the other hand, if the ratio is less than the above range, the number of bonding points increases and the degree of freedom between filaments (e.g. inter-fiber movement) is limited; can result in damage.

For example, the melting point T _H of the high melting point polyester may be 250° C. or higher. Specifically, the lower limit of the melting point T _H of the high melting point polyester may be, for example, 255°C or higher, 260°C or higher, 265°C or higher, or 270°C or higher. The upper limit of the melting point T _H of the high melting point polyester is not particularly limited, but may be, for example, 290°C or lower, 285°C or lower, 280°C or lower, 275°C or lower, 270°C or lower, 265°C or lower, or 260°C or lower.

As an example, the melting point T _L of the low melting point polyester may be less than 250°C. Specifically, the upper limit of the melting point T _L of the low melting point polyester is, for example, 245°C or less, 240°C or less, 235°C or less, 230°C or less, 225°C or less, 220°C or less, 215°C or less, 210°C or less , 205°C or less, 200°C or less, 195°C or less, 180°C or less, 175°C or less, 170°C or less, 165°C or less, 160°C or less, or 155°C or less. The lower limits are, for example, 150°C or higher, 155°C or higher, 160°C or higher, 165°C or higher, 170°C or higher, 175°C or higher, 180°C or higher, 185°C or higher, 190°C or higher, 195°C or higher, and 200°C. The temperature may be 205°C or higher, 210°C or higher, 215°C or higher, 220°C or higher, 225°C or higher, or 230°C or higher. If the melting point temperature of the low melting point polyester is below the above range, the low melting point polyester component is likely to melt due to the heat applied during the process related to the nonwoven fabric, which may cause breakage and thermal shrinkage of the nonwoven fabric (or cellular paper). Cheap. In addition, if the melting point temperature of the low melting point polyester exceeds the above range, the flexibility of the nonwoven fabric will decrease, and the difference in elongation between the coating resin and the like used when manufacturing the carpet will increase, and this will affect the usage period of the carpet. A problem arises in which the edge of the carpet becomes more warped as time passes.

For example, the high melting point polyester may have an intrinsic viscosity (IV) of 0.640 or more. For example, the lower limit of the intrinsic viscosity of the high melting point polyester may be, for example, 0.645 or more or 0.650 or more. The upper limit is not particularly limited, but may be, for example, 0.700 or less.

For example, the low melting point polyester may have an intrinsic viscosity (IV) of 0.725 or more. Specifically, the lower limit of the intrinsic viscosity of the low melting point polyester may be, for example, 0.750 or more, 0.800 or more, 0.850 or more, or 0.900 or more. The upper limit is not particularly limited, but may be, for example, 0.950 or less.

Regarding the high melting point and low melting point polyesters, the type of polyester is not particularly limited. For example, Polyethylene Terephthalate, polybuttylene Terephthalate, Polynaphtalene Telephalate (Polynaphtalene Terene Tereph) Polyester such as THALATE can be used. Specifically, the web may contain at least one of the polyesters listed above as a polyester component.

As an example, the low melting point polyester may be a copolyester. For example, the low melting point polyester may be a polyester copolymerized with adipic acid, a polyester copolymerized with isophthalic acid, or a polyester copolymerized with adipic acid and isophthalic acid. These copolymers can be manufactured by adding copolymerizable monomers such as adipic acid and isophthalic acid during the polymerization process.

As an example, the spinning can be performed at a temperature higher than the melting point T _H of the high melting point polyester (for example, at a temperature of 260° C. or higher). Such spinning can be performed using a known device.

Although not particularly limited, the spinning can be performed at a speed of 3,500 to 6,000 m/min.

For example, the two types of polyesters are spun from the same or different nozzles of a spinneret through respective holes, cooled at the same time, and solidified as a result. The cooling method is not particularly limited, and for example, cooling air at an appropriate temperature or atmospheric temperature (room temperature) can be used.

As an example, the filament can be drawn at a predetermined draw ratio. For example, the cooled filaments can be drawn at a predetermined spinning speed, and each filament is split at regular intervals.

The method includes a second step of bonding the webs. Specifically, the second step may be a step of applying heat to the webs to bond the webs. This step binds the webs and results in a so-called fixed-form nonwoven fabric.

Applying heat to the webs to bond them can be performed by known methods. For example, a roll (eg, a calendar roll or an embossing roll) or a roller or hot air through (HAT) is used. At this time, it can also be performed together with pressurization. The form of the roll, the method of applying hot air and the means or methods of maintaining the respective thermal bonding temperature (or providing heat to the web) can be suitably selected by those skilled in the art from known techniques.

As an example, the method may include passing the web through a roll having a first thermal bonding temperature _T1 , and applying a second thermal bonding temperature _T2 to the web passed through the roll to bond the web. That is, specifically, the second step is performed by passing the web through a roll that maintains a first thermal bonding temperature _T1 , and applying a second thermal bonding temperature _T2 using hot air to the web that has passed through the roll. be able to. At this time, the first thermal bonding temperature _T1 may be lower than the second thermal bonding temperature _T2 . Although not particularly limited, the web may pass between two rolls, in which case pressure is applied to the web between the two rolls.

For example, the second thermal coupling temperature T ₂ due to the hot air may be the same as or higher than the first thermal coupling temperature T ₁ .

For example, the first thermal bonding temperature T ₁ may range from 120 to 190°C. Appropriate morphological stability of the nonwoven fabric can be imparted at this temperature.

For example, the second thermal coupling temperature T ₂ due to the hot air may range from 140 to 240°C. Appropriate morphological stability of the nonwoven fabric can be imparted at this temperature.

For example, the second thermal coupling temperature _T2 may be higher than the first thermal coupling temperature _T1 . Specifically, the temperature difference between the first thermal bonding temperature T ₁ and the second thermal bonding temperature T ₂ may be in a range of 20 to 60° C. (T ₂ >T ₁ ). Appropriate morphological stability of the nonwoven fabric can be imparted at this temperature.

The method includes a third step of coating the bonded web (eg, nonwoven) with an oil.

The oil agent can form a film on the surface of the web (nonwoven fabric) or the filaments forming the web. The coating can reduce friction between the needle and the nonwoven fabric that occurs when the needle passes through the tufting process, thereby preventing damage to the web or the fibers forming the web. Furthermore, since heat generation due to friction is reduced through the oil film, the life of the needle can be extended.

As an example, the oil agent may be applied (coated) to the bonded web (or the filaments forming the same) in a content of 0.05% by weight or more based on 100% by weight of the total weight of the nonwoven fabric. can. At this time, the total weight of the nonwoven fabric, which serves as a reference for the oil content, is, for example, the weight of the nonwoven fabric to which the oil has been applied in the third stage, the weight of the nonwoven fabric that has undergone the web bonding stage, or the weight of the nonwoven fabric that has undergone the fourth stage described below. It can be the weight of the nonwoven fabric manufactured by Specifically, the lower limit of the content of the oil agent is, for example, 0.1% by weight or more, 0.15% by weight or more, 0.20% by weight or more, 0.25% by weight or more, 0.30% by weight or more. , 0.35% by weight or more, 0.40% by weight or more, 0.45% by weight or more, or 0.50% by weight or more. The upper limit of the content of the oil agent is, for example, 5.0% by weight or less, 4.5% by weight or less, 4.0% by weight or less, 3.5% by weight or less, 3.0% by weight or less, 2. It can be 5% by weight or less, 2.0% by weight or less, 1.5% by weight or less, or 1.0% by weight or less. If the oil content is less than the above range, the oil content will be insufficient and the oil will not be able to penetrate uniformly into the filaments that form the nonwoven fabric, making it difficult to form a sufficient oil film, and as a result, the tufting process will be delayed. The filament may be damaged during the process. Furthermore, if a small amount of oil is used, the tufting properties will be poor and the BCF yarn will come off. If the content of the oil agent exceeds the above range, slippage increases, making it unsuitable for the winding process and making tension control difficult. In addition, excess oil will stick to the needle bar used in the tufting process, leaving dust and other foreign matter on the oil adhering to the needle bar, which will cause the carpet threads to be evenly spaced during the tufting process. It may prevent it from being planted.

The type of oil that can be used is not particularly limited. For example, as the oil agent, a silicone oil agent or an ester oil agent can be used.

The method includes a fourth step of applying heat such that the bonded web or nonwoven fabric to which the oil agent has been applied has a latent stress index of 5.00 or less. The present inventor has experimentally confirmed by confirming in the experimental examples described later that when the latent stress index exceeds 5.00, the degree of curling of the product becomes significant and the shape stability is poor. The latent stress index is determined according to DIN 53369 by exposing the non-woven fabric at a temperature of 180°C within 5 minutes, and then cooling the non-woven fabric at room temperature for about 1 minute, and then the measured cooling stress (cN) of the non-woven fabric. It can be calculated by dividing by the unit weight (g/m ² ).

For example, the bonded web (nonwoven fabric) may have a latent stress index of 5.00 or less in machine direction or mechanical direction (MD).

For example, the bonded web (nonwoven fabric) may have a latent stress index of 5.00 or less in cross direction (CD).

As an example, the latent stress index of the bonded web (nonwoven) can be 5.0 or less in MD and CD.

Specifically, in MD and/or CD, the upper limit of the latent stress index is, for example, 4.9 or less, 4.8 or less, 4.7 or less, 4.6 or less, 4.5 or less, 4.4 or less. , 4.3 or less, 4.2 or less, 4.1 or less, or 4.0 or less. The lower limit of the latent stress index may be, for example, 1.5 or more, 2.0 or more, 2.5 or more, 3.0 or more, or 3.5 or more.

As an example, the step of applying heat to relax (latent) stress can be performed at a predetermined temperature _T3 . Specifically, the step of applying heat to relax the stress can be performed at a temperature _T3 that satisfies the following relational expression 1.

[Relational expression 1]
20℃≦Melting point T _L of low melting point polyester - Temperature T ₃ ≦60℃

That is, the melting point T _L of the low melting point polyester is greater than the temperature T ₃ , and the difference between the melting point T _L of the low melting point polyester and the temperature T ₃ can be in the range of 20 to 60°C.

When the fourth step is performed while applying heat at a temperature T3 that satisfies relational expression ₁ , not only the coated oil is dried, but also the process of manufacturing a nonwoven fabric (e.g., thermal bonding for bonding webs) This effectively reduces the latent stress imparted to the nonwoven fabric (or web) during the process (e.g. step). This makes it possible to improve product shape instability (for example, curling or edge warping) caused by latent stress.

Specifically, the lower limit of the temperature difference (ΔT=T _L −T ₃ ) is, for example, 25°C or more, 30°C or more, 35°C or more, 40°C or more, 45°C or more, 50°C or more, or 55°C or more. The upper limit can be, for example, 55°C or less, 50°C or less, 45°C or less, 40°C or less, 35°C or less, 30°C or less, or 25°C or less. If the temperature difference (ΔT=T _L −T ₃ ) is less than the above range, the stiffness of the nonwoven fabric will increase, the tufting performance will decrease, the width shrinkage of the nonwoven fabric will increase, and the initial The physical properties of the non-woven fabric become severely deformed, making it difficult to use the non-woven fabric as aerated paper for tile carpets. Particularly, when the temperature difference is less than the temperature difference (ΔT=T _L −T ₃ ), the tear strength of the nonwoven fabric is significantly reduced, causing a problem that the tile carpet cellular paper is torn after tufting. Conversely, if the temperature difference (ΔT=T _L −T ₃ ) exceeds the above range, it is difficult to effectively reduce the latent stress.

The method of applying heat at a temperature _T3 that satisfies the above-mentioned relational expression 1 is not particularly limited. Known means and methods are conceivable to provide the temperature T ₃ that satisfies equation 1 above, such as, for example, using a cylinder dryer or applying hot air.

For example, the temperature _T3 at which the process of applying heat to relieve stress may satisfy the following relational expression 2. Considering the entire process of manufacturing a nonwoven fabric, it is advantageous for the temperature T ₃ to satisfy relational expression 2 to alleviate latent stress.

[Relational expression 2]
First thermal bonding temperature T ₁ ≦Temperature T ₃ ≦Second thermal bonding temperature T ₂

For example, the step of applying heat to relieve stress may be performed at the temperature _T3 for 10 to 130 seconds. For example, the time during which the step of relaxing stress by applying heat at the temperature _T3 is performed is 20 seconds or more, 30 seconds or more, 40 seconds or more, 50 seconds or more, 60 seconds or more, 70 seconds or more, 80 seconds or more, It can be 90 seconds or more, 100 seconds or more, 110 seconds or more, or 120 seconds or more. And the upper limit can be, for example, 120 seconds or less, 110 seconds or less, 100 seconds or less, 90 seconds or less, 80 seconds or less, 70 seconds or less, 60 seconds or less, 50 seconds or less, 40 seconds or less, or 30 seconds or less. . If the time is less than the above range, the nonwoven fabric will not relax sufficiently and the effect of the reheat treatment will not be sufficiently obtained. In addition, if the time exceeds the above range, not only the physical properties of the nonwoven fabric or the cellular paper produced therefrom will be deformed, but also the production equipment will become excessively large, reducing productivity and increasing manufacturing costs.

As an example, the thickness of the nonwoven fabric produced by the method may be in the range of 0.20 to 0.60 mm. Specifically, the lower limit of the thickness of the nonwoven fabric is, for example, 0.25 mm or more, 0.30 mm or more, 0.35 mm or more, or 0.40 mm or more, and the upper limit is, for example, 0.55 mm or less, 0.50 mm or less. , 0.45 mm or less, or 0.40 mm or less.

For example, the unit weight, ie, basis weight, of the nonwoven fabric produced by the method may be 70 to 140 g/m ² . Specifically, the lower limit of the basis weight of the combined web is, for example, 75 g/m ² or more, 80 g/m ² or more, 85 g/m ² or more, 90 g/m ² or more, 95 g/m ² or more, 100 g/m ² or more or 105 g/m ² or more, and the upper limit is, for example, 135 g/m ² or less, 130 g/m ² or less, 125 g/m ² or less, 120 g/m ² or less, 115 g/m ² or less, 110 g/m ² It may be less than or equal to 105 g/m ² , less than or equal to 100 g/m ² , less than or equal to 95 g/m ² , or less than or equal to 90 g/m ² . When the above range is satisfied, appropriate levels of lightness and mechanical properties can be ensured.

As an example, the nonwoven fabric produced by the method may simultaneously have the thickness and basis weight described above. For example, the nonwoven fabric may have a thickness of 0.30-0.40 mm and a basis weight of 85-95 g/m ² . Alternatively, the nonwoven fabric may have a thickness of 0.35 to 0.55 mm and a basis weight of 90 to 120 g/m ² , for example.

In another example, the invention relates to nonwoven fabrics. The nonwoven fabric can be provided by the manufacturing method described above.

The nonwoven fabric includes a high melting point polyester thread and a low melting point polyester thread that are fused to each other; and an oil agent, and can satisfy a latent stress index of 5.00 or less. Specifically, the high melting point polyester yarn and the low melting point polyester yarn fused together form a nonwoven fabric (or web), and the oil agent is coated on each polyester yarn or nonwoven fabric (or web) to form a film. can be formed. The nonwoven fabric may have a latent stress index in MD and/or CD of, for example, 5.0 or less. The specific latent stress index is as explained in the content regarding the manufacturing method.

As an example, the latent stress index of the bonded web (nonwoven) can be 5.0 or less in the MD and CD directions. The specific latent stress index is as explained in the content regarding the manufacturing method.

As an example, the thickness of the nonwoven fabric may be in the range of 0.20 to 0.60 mm. The specific thickness is as explained in the content regarding the manufacturing method.

For example, the unit weight, ie, basis weight, of the nonwoven fabric may be 70 to 140 g/m ² . The specific weight of the nonwoven fabric is as explained in the content regarding the manufacturing method.

As an example, the nonwoven fabric may include 80 to 92% by weight of the high melting point polyester yarn and 8 to 20% by weight of the low melting point polyester yarn. The specific weight ratios among the components are as explained in the content regarding the manufacturing method.

As an example, in the nonwoven fabric, the ratio (N ₁ /N ₂ ) of the number N ₁ of the high melting point polyester yarns (number of filaments) to the number N ₂ of the low melting point polyester yarns is in the range of 2.0 to 5.0. It can be. The specific number ratio is as explained in the content regarding the manufacturing method.

The tenacity of the high melting point polyester thread and the low melting point polyester thread contained in the nonwoven fabric is as explained in the content regarding the manufacturing method.

The melting points of the polyesters contained in the high melting point polyester yarn and the low melting point polyester yarn are as explained in the description regarding the manufacturing method.

The types of polyester contained in the high melting point polyester yarn and the low melting point polyester yarn are as explained in the content regarding the manufacturing method.

Other configurations included in the nonwoven fabric, such as components used in the production of the nonwoven fabric and their characteristics, have been explained in relation to the manufacturing method, and therefore will be omitted.

In yet another example, the invention relates to a method of manufacturing a carpet. The method may include the step of planting carpet fibers on one surface of the nonwoven fabric manufactured by the above method using a needle.

Specifically, the method includes:
A first step of producing a web by melt spinning a high melting point polyester having a melting point T _{H and a low melting point polyester having a melting point T L lower} than the melting point T _H ;
a second step of joining the webs;
a third step of applying an oil to the bonded web (e.g. nonwoven);
a fourth step of applying heat so that the latent stress index of the nonwoven fabric to which the oil agent has been applied is 5.00 or less;
a fifth step of planting carpet yarn on one side of the nonwoven fabric using a needle; The carpet yarn can be, for example, BCF yarn.

Regarding the carpet manufacturing method, the first to fourth steps are as described above.

The fifth step is a so-called tufting step, and can be performed using known methods and devices. For example, the tufting may be of a predetermined gauge (eg, 1/10 gauge) in the form of a loop. The tufting process is performed so that the carpet yarn has a predetermined softness (eg, 500 to 1,500 denier) and height (eg, 3.0 to 0.7 mm). Through the tufting process, the carpet fibers are visibly planted on one side of the nonwoven fabric.

For example, the carpet manufacturing method may further include a sixth step of applying a resin coating liquid to the back surface. The process of imparting shape stability to the carpet is called a back coating process, and the term "back side" here means, for example, the side opposite to the side where the carpet fibers are visually recognized. In some cases, a glass mat may be used together with the resin component in the back coating process, and hot air may be applied to dry the coating liquid.

The type of resin contained in the coating liquid for back coating is not particularly limited. For example, the coating liquid may include a resin component such as PVC, PE, EVA, or SBR. Such a coating solution or a back coating layer obtained therefrom may be formed of one or more layers.

For example, the method may further include a seventh step of cutting the obtained carpet into a predetermined size after the resin coating liquid applied to the rear surface is dried. After passing through this step, a tile carpet can be manufactured.

Curling, in which the four corners of a manufactured carpet tile are warped, may occur. If the degree of curl is severe, it may be impossible to install carpet tiles, so it is necessary to reduce the degree of curl. Such attempts have continued in related technical fields. As mentioned above, the present invention allows the problem of carpet curl to be efficiently managed and prevented by quantitatively confirming and evaluating the latent stress remaining in the nonwoven fabric during the manufacturing process of the nonwoven fabric.

In yet another example, the invention relates to a carpet. The carpet includes a nonwoven fabric with the above-mentioned characteristics and yarns embedded in the nonwoven fabric. The carpet may have an improved problem of curling at corners.

For example, the carpet may be a tile carpet.

Other details such as the structure and manufacturing method of the carpet are as described above, and will therefore be omitted.

According to the present invention, it is possible to provide a nonwoven fabric, a carpet, and a method for producing the same, which have improved curling problems and have excellent shape stability. Further, the present invention can provide a nonwoven fabric whose shape stability can be quantitatively evaluated and predicted, and a method for manufacturing the same.

Hereinafter, the functions and effects of the present invention will be explained in more detail using specific embodiments of the present invention. However, such embodiments are merely presented as examples of the present invention, and the scope of the present invention is not limited thereby.

<Examples and comparative examples>
Example 1
PET raw material (first component raw material) having an intrinsic viscosity (IV) of 0.645 and a melting temperature of 254°C; and Co- having an intrinsic viscosity (IV) of 0.920 and a melting temperature of 171°C. A PET raw material (second component raw material) (Co-PET produced using adipic acid as a comonomer) was prepared. Then, each of the raw materials was spun into filament fibers using a spunbond manufacturing apparatus at a spinning speed of 5,000 m/min and a spinning temperature of 270°C. At this time, the hardness of the first component PET is adjusted to 8.5De', the hardness of the second component Co-PET is adjusted to 3.6De', and the first component PET and the second component Co-PET are The weight ratio (wt%) was adjusted to 85:15. Further, the ratio (N ₁ /N ₂ ) between the first number N ₁ of filaments and the second number N ₂ of filaments was adjusted to 2.3.

The spun filament fibers were laminated into a web on a moving conveyor net, and then primary bonded at a calender temperature of 140°C and secondary bonded at a HAT hot air temperature of 175°C to produce a spunbond nonwoven fabric. Next, the nonwoven fabric was coated with an oil agent so that the content of the oil agent was about 0.5 wt % based on 100 weight % of the total weight of the manufactured nonwoven fabric. The basis weight of the oil coated non-woven fabric is approximately 90 gsm and the thickness is approximately 0.34 mm. After coating with the oil agent, the tensile strength, tear strength, and latent stress index described below were measured.

The manufactured nonwoven fabric (carpet foam paper) was put into a separate cylinder-shaped heat treatment device, and was reheated at a temperature of 150° C. for 20 seconds while moving at a speed of 30 m/min. After the reheat treatment, the tensile strength, tear strength, shrinkage rate, and latent stress index described below were measured.

Then, tufting was performed on the nonwoven fabric (carpet aerated paper) (1/10 gauge, carpet yarn (BCF) 1240 De', pile yarn height 4.0 mm). Thereafter, 6.4 kg/m ² of PVC solution and Glass Mat were coated on the aerated paper on which the carpet fibers were tufted to produce a tile carpet. For the final manufactured tile carpet, the curl values for the four corners of the tile carpet were measured (via Aachen evaluation) as described below.

Example 2
A nonwoven fabric and a carpet were manufactured in the same manner as in Example 1, except that the reheat treatment was performed at a speed of 10 m/min for 60 seconds.

Example 3
The melting point and intrinsic viscosity (IV) of Co-PET, which is the second component raw material, are 226°C and 0.820, respectively, the spinning temperature of the second component raw material is 280°C, the calendering temperature is 180°C, and the HAT A nonwoven fabric and a carpet were manufactured through the same process as in Example 1, except that the hot air temperature was 205°C and the reheating treatment was performed at a speed of 30 m/min at a temperature of 205°C for 20 seconds.

Example 4
A nonwoven fabric and a carpet were manufactured in the same manner as in Example 3, except that the reheat treatment was performed at a speed of 10 m/min for 60 seconds.

Example 5
A nonwoven fabric and a carpet were manufactured through the same process as in Example 4, except that the reheat treatment temperature was set at 175°C.

Comparative example 1
A nonwoven fabric and a carpet were manufactured in the same manner as in Example 1, except that the reheat treatment was performed at a speed of 120 m/min for 5 seconds.

Comparative example 2
A nonwoven fabric and a carpet were manufactured through the same process as in Example 1, except that the reheat treatment was performed at 160°C.

Comparative example 3
A nonwoven fabric and a carpet were manufactured in the same manner as in Example 1, except that the reheat treatment was performed at a speed of 4 m/min and a temperature of 150° C. for 150 seconds.

Comparative example 4
A nonwoven fabric and a carpet were manufactured through the same process as in Example 3, except that the reheat treatment was performed at a speed of 120 m/min and a temperature of 205° C. for 5 seconds.

Comparative example 5
A nonwoven fabric and a carpet were manufactured through the same process as in Example 3, except that the reheat treatment was performed at a temperature of 220°C.

Comparative example 6
A nonwoven fabric and a carpet were manufactured through the same process as in Example 3, except that the reheat treatment was performed at a speed of 4 m/min and a temperature of 205° C. for 150 seconds.

Comparative example 7
A nonwoven fabric and a carpet were manufactured through the same process as in Example 3, except that the reheat treatment was performed at a speed of 5 m/min and a temperature of 100° C. for 120 seconds.

A comparison of the manufacturing processes of the nonwoven fabrics of Examples and Comparative Examples is as follows.

<Physical property evaluation method>
The following physical properties were evaluated for the nonwoven fabrics and/or carpets manufactured in Examples and Comparative Examples, and the results are shown in Tables 2 and 3.

1. Tensile strength (kgf/5cm)
Tensile strength was measured using KS K 0521 (Cut Strip). Specifically, the spunbond nonwoven fabrics of Examples and Comparative Examples were manufactured into test pieces with a size of 20 cm x 5 cm, and tested using a universal tensile tester (Instron) while applying a tensile speed of 200 mm/min to the test pieces. The tensile strength in each of the MD and CD directions was measured. Such tensile strength was measured before and after reheat treatment, respectively, to measure the latent stress index.

2. Tear strength (kgf)
Tear strength was measured using KS K 0536 (Single Tongue). Specifically, the spunbond nonwoven fabrics of Examples and Comparative Examples were manufactured into test pieces with a size of 7.6 cm x 20 cm, and the test pieces were tested in a universal tensile tester (Instron) while applying a tensile speed of 300 mm/min to the test pieces. The tear strength in each of the MD and CD directions was measured using The tear strength was measured before and after reheat treatment to measure the latent stress index.

3. Latent Stress Index The spunbond nonwoven fabrics of the Examples and Comparative Examples were produced in test pieces with dimensions of 5.0 cm x 70 cm, and the latent stress was measured according to DIN 53369 (Thermal shrinkage and shrinkage force). Specifically, according to DIN 53369, after fixing the nonwoven fabric with a load of 50 g, the thermal stress (cN) can be measured in a chamber at 180 °C for 2 minutes; After 2 minutes had passed, the nonwoven fabric was exposed to the atmosphere for 1 minute, and the cooling stress (latent stress) was measured. Then, the measured cooling stress (cN) was divided by the unit weight (g/m ² ) of the test piece to obtain a latent stress index. The latent stress index is treated as a dimensionless constant.

Such tensile strength was measured before and after reheat treatment for measurement of latent stress index, respectively.

4. Width shrinkage rate (%)
The rate of change before and after the reheating treatment is expressed as a shrinkage rate based on the width of 3.8 m, which is the width of a general nonwoven fabric used as carpet foam paper. Then, this was calculated for the nonwoven fabrics manufactured in Examples and Comparative Examples.

Width shrinkage rate (%)
= [(Width of nonwoven fabric before reheat treatment) - (Width of nonwoven fabric after reheat treatment)] / (Width of nonwoven fabric before reheat treatment) x 100
At this time, the width of the nonwoven fabric before reheat treatment is 3.8 mm.

5. Curling (mm)
Curl was measured according to DIN EN986 (Aachen Test). Specifically, a tile carpet (50 x 50 cm) was preheated in an oven at 60°C for about 30 minutes, and the preheated tile carpet was immersed in water containing 1 wt% of surfactant for about 30 minutes. After that, preheating treatment was performed in an oven at 60° C. for 24 hours. After the preheated tile carpet was left at room temperature for 48 hours, the curl height was measured. At this time, the curl is the average value of the curl heights measured for each of the four corners.

According to Tables 2 and 3 above, when reheating is performed under the conditions of the example and the latent stress index is adjusted to 5.0 or less, the average width shrinkage rate of the nonwoven fabric and the degree of curl of the carpet are higher than those of the comparative example. It was found that it is possible to simultaneously reduce That is, according to the present invention, a nonwoven fabric and a carpet with excellent shape stability can be provided.

On the other hand, when comparing the degree of change in tensile strength and tear strength before and after reheat treatment by arithmetic averaging, it is found that when reheat treatment according to this example is performed, the change in tensile strength and tear strength before and after reheat treatment is large. I found out that there isn't. This means that mechanical properties and morphological stability can be ensured at the same time by the reheat treatment according to the present invention.

Claims (20)

A first step of producing a web by melt spinning a high melting point polyester having a melting point T _{H and a low melting point polyester having a melting point T L lower} than the melting point T _H ;
a second step of joining the webs;
a third step of applying an oil to the bonded web;
a fourth step of applying heat so that the latent stress index of the nonwoven fabric to which the oil has been applied is 5.00 or less (provided that the latent stress index is at a temperature of 180° C. according to DIN 53369); After exposing the non-woven fabric within 5 minutes and cooling the non-woven fabric to room temperature for about 1 minute, the measured cooling stress (cN) is divided by the unit weight (g/m ² ) of the non-woven fabric. , which is a dimensionless constant). The method for producing a nonwoven fabric according to claim 1, wherein the fourth step is performed by applying heat for 10 seconds to 130 seconds at a temperature _T3 that satisfies the following relational expression 1:
[Relational expression 1]
20℃≦Melting point T _L of low melting point polyester - Temperature T ₃ ≦60℃ The method for producing a nonwoven fabric according to claim 1, wherein a web containing 80 to 92% by weight of high melting point polyester yarn and 8 to 20% by weight of low melting point polyester yarn is produced. 4. A web comprising the high melting point polyester yarn having a softness of 7.0 to 10.0 denier and the low melting point polyester yarn having a softness of 2.0 to 5.0 denier is produced. A method for producing a nonwoven fabric. producing a web in which the ratio (N ₁ /N ₂ ) of the number _{N 1 of} the high melting point polyester yarns (number of filaments) to the number N 2 of the low melting point polyester yarns is in the range of 2.0 to 5.0; The method for producing a nonwoven fabric according to claim 3 or 4. The method for producing a nonwoven fabric according to claim 3, wherein the high melting point polyester has a melting point _TH of 250°C or higher, and the low melting point polyester has a melting point _TL of 245°C or lower. The polyester is at least one selected from polyethylene terephthalate, polybutylene terephthalate, and polynaphthalene terephthalate. The method for producing a nonwoven fabric according to claim 1. The method for producing a nonwoven fabric according to claim 7, wherein the low melting point polyester is a polyester copolymerized with one or more of adipic acid and isophthalic acid. The production of a nonwoven fabric according to claim 1, wherein the web is bonded by passing the web through a roll having a first thermal bonding temperature _T1 , and applying a second thermal bonding temperature _T2 to the web that has passed through the roll. method (provided that the second thermal bonding temperature _T2 is higher than or equal to the first thermal bonding temperature _T1 ). The method of manufacturing a nonwoven fabric according to claim 9, wherein the first thermal bonding temperature T ₁ is in the range of 120 to 190°C, and the second thermal bonding temperature T ₂ is in the range of 140 to 240°C. The method for manufacturing a nonwoven fabric according to claim 9 or 10, wherein the temperature _T3 satisfies the following relational expression 2:
[Relational expression 2]
First thermal bonding temperature T ₁ ≦Temperature T ₃ ≦Second thermal bonding temperature T ₂ 2. The method for producing a nonwoven fabric according to claim 1, wherein an oil agent is applied to the bonded web in a content of 0.05% by weight or more based on 100% by weight of the total weight of the nonwoven fabric. A nonwoven fabric containing a high melting point polyester thread and a low melting point polyester thread that are fused together; and an oil agent;
The nonwoven fabric is a nonwoven fabric having a latent stress index of 5.00 or less (however, the latent stress index is determined by exposing the nonwoven fabric at a temperature of 180° C. within 5 minutes according to DIN 53369, and leaving the nonwoven fabric at room temperature for about 1 minute. After cooling, the measured cooling stress (cN) divided by the unit weight of the nonwoven fabric (g/m ² ) is a dimensionless constant). The nonwoven fabric according to claim 13, having a thickness in the range of 0.20 to 0.60 mm and a unit weight in the range of 70 to 140 g/m ² . The nonwoven fabric according to claim 13, comprising 80 to 92% by weight of the high melting point polyester yarn and 8 to 20% by weight of the low melting point polyester yarn. Claim 13, wherein the ratio (N ₁ /N ₂ ) of the number _{N 1 of} the high melting point polyester yarns (number of filaments) to the number N 2 of the low melting point polyester yarns is in the range of 2.0 to 5.0. Nonwoven fabric as described. The nonwoven fabric according to claim 13, wherein the high melting point polyester yarn has a softness of 7.0 to 10.0 denier, and the low melting point polyester yarn has a softness of 2.0 to 5.0 denier. The nonwoven fabric according to claim 13, wherein the high melting point polyester has a melting point _TH of 250°C or higher, and the low melting point polyester has a melting point _TL of 245°C or lower. A method for manufacturing a carpet, comprising the step of planting carpet yarn on one side of the nonwoven fabric manufactured by the method according to claim 1 using a needle. A carpet comprising the nonwoven fabric according to claim 13 and yarns planted in the nonwoven fabric.