KR101192924B1 - Artificial leather and method for manufacturing the same - Google Patents

Abstract

The present invention is made by impregnating a polymer elastic body in a nonwoven fabric composed of ultrafine fibers, the polymer elastic body is contained in 20 to 30% by weight, characterized in that the linear density of raised brush protruding on the surface is 20 ~ 35 bone / 100㎛ range As related to artificial leather and its manufacturing method,

According to the present invention, by optimizing the content of the polymer elastomer has an elongation characteristic suitable for the molding process, by optimizing the linear density of the brushing can be obtained artificial leather with improved appearance and feel, excellent surface with a lot of bending like car headliner It can be easily used for products requiring quality.

Artificial Leather, Shinto, Appearance

Description

Artificial leather and method for manufacturing the same

The present invention relates to artificial leather, and more particularly to an artificial leather having an excellent elongation characteristic and excellent appearance and feel.

Artificial leather is made by impregnating a polymer elastic body in a nonwoven fabric formed by interweaving microfibers three-dimensionally, and has a soft texture and unique appearance similar to that of natural leather, and thus makes shoes, clothing, gloves, sundries, furniture, and automobile interior materials. It is widely used in various fields such as.

Such artificial leathers are required to have higher functionality in terms of flexibility, surface quality, wear resistance, light resistance, or elongation, depending on the intended use, and various properties may be required at the same time.

For example, when artificial leather is applied to a headliner attached to a car ceiling among automotive interior materials, optimized elongation characteristics are required for ease of molding process, and as the consumer's eye height is increased, Excellent appearance and tactile properties are required.

In other words, in the case of the headliner attached to the ceiling of the car, there are many bends depending on the shape of the car body.When using artificial leather with low elongation characteristics in the car headliner, the product quality is reduced due to the wrinkles generated in the artificial leather during molding. Problems will arise. Therefore, artificial leather for use in a product having a lot of bends such as a car headliner should have excellent elongation characteristics. Thus, in the prior art, there has been an effort to improve the elongation characteristics of artificial leather by reducing the content of the polymer elastic body impregnated in the nonwoven fabric. In this case, the elongation is too large, and the artificial leather is excessively stretched during molding, which causes wrinkles. The same problem arose and, together with the decrease in the content of the polymer elastomer, the appearance and touch of the artificial leather was deteriorated.

It is an object of the present invention to provide an artificial leather having an optimum elongation characteristic that can be easily applied to a product having a large number of curved parts and having an excellent appearance and feel and a method of manufacturing the same.

The present inventors confirmed the optimum range of elongation characteristics through a number of repeated tests to obtain artificial leather with elongation characteristics optimized for molding, and the elongation characteristics of such artificial leathers depend on the content of the polymer elastomer impregnated in the nonwoven fabric. It was found to be greatly affected by. That is, the polyurethane used as the polymer elastic body is easily stretched than the fiber and has excellent recovery properties. However, it was confirmed that increasing the content of polyurethane may interfere with the extension of artificial leather and cause side effects such as discoloration of color when exposed to light for a long time. However, if the content of polyurethane is reduced too much, wrinkles occur during molding and the appearance of artificial leather is very degraded. Therefore, in order to obtain artificial leather having optimized elongation characteristics, it is necessary to optimize the content of the polymer elastic body, and thus, an optimal range of content of the polymer elastic body has been set through a number of experiments.

In addition, the appearance and feel of the artificial leather is affected by the raised protruding surface of the artificial leather. Specifically, when the napping is distributed in too small density or in too large density, the appearance and feel are inferior, so the napping should be distributed at the optimum density to enhance the appearance and feel, and also within the same density range. Should be uniformly arranged to enhance appearance and feel. Therefore, the present inventors have set the optimum distribution range of the raised protruding on the surface of artificial leather through a number of repeated test studies, devised a method for forming the raised with such an optimal distribution range to complete the present invention Was done.

Specific problem solving means according to the present invention described above is as follows.

The present invention is made by impregnating a polymer elastic body in a nonwoven fabric composed of ultrafine fibers, the polymer elastic body is contained in 20 to 30% by weight, characterized in that the linear density of raised brush protruding on the surface is 20 ~ 35 bone / 100㎛ range Provide artificial leather.

The artificial leather may have a surface roughness of 40 μm or less.

The artificial leather has a 5kg static load elongation in the length direction of 20 to 40%, and the width direction in the range of 40 to 80%.

The ultrafine fibers may be made of polyethylene terephthalate, polytrimethylene terephthalate, or polybutylene terephthalate, and the polymer elastomer may be made of polyurethane.

The microfibers may have a fineness range of 0.3 denier or less.

The present invention is a process for producing an island-in-the-sea fiber consisting of a first polymer of the sea component and a second polymer of the island component having different characteristics dissolved in a solvent; Manufacturing a nonwoven fabric using the island-in-the-sea fibers; Immersing the nonwoven fabric in a polymer elastomer solution to impregnate the polymer elastic body with the nonwoven fabric; Dissolving and removing the first polymer as a sea component in the nonwoven fabric; And a step of raising the surface of the nonwoven fabric, and after the impregnating of the polymer elastic body, rearranging the polymer elastic body on the surface of the nonwoven fabric to perform a process of uniformly aligning the fibers. It provides a method of manufacturing.

The process of rearranging the polymer elastomer may be performed using a heated roll.

The process of rearranging the polymer elastomer may be performed once or plural times.

The process of dissolving and removing the first polymer that is a sea component in the nonwoven fabric may be performed before or after the process of impregnating the polymer elastic body in the nonwoven fabric.

In the process of manufacturing the island-in-the-sea fibers, the first polymer is included in 10 to 60% by weight, the second polymer is included in 40 to 90% by weight, and the first polymer using a copolyester As the second polymer, polyethylene terephthalate, polytrimethylene terephthalate, or polybutylene terephthalate may be used.

According to the present invention as described above, the following effects can be obtained.

The present invention optimizes the content of the polymer elastic body, specifically, by adjusting the content of the polymer elastic body in artificial leather to 20 to 30% by weight, the elongation characteristics optimized for molding, specifically 5kg static load elongation 20 to 40 %, The width of the artificial leather can be obtained in the range of 40 to 80%. In addition, the present invention can improve the appearance and feel of artificial leather by optimizing the linear density of brushed and the surface roughness of artificial leather.

Therefore, the artificial leather according to the present invention can be easily used in a product such as a car headliner that requires a lot of bending and excellent surface quality.

Hereinafter, preferred embodiments of the present invention will be described in detail.

1. Artificial leather and its manufacturing method

Artificial leather according to the present invention is made by impregnating a polymer elastic body in a nonwoven fabric composed of ultrafine fibers.

The polymer elastomer may be polyurethane, and specifically, polycarbonate diol, polyester diol, or polyetherdiol may be used alone or in combination thereof, but is not necessarily limited thereto.

The polymer elastomer is included in 20 to 30% by weight in artificial leather. If the polymer elastomer is included in less than 20% by weight can not obtain the desired elongation, if the polymer elastomer is included in more than 30% by weight because the feel of artificial leather, there is a risk of color discoloration and elongation may be lowered to be. As described above, the artificial leather according to the present invention containing 20 to 30% by weight of the polymer elastic body has an optimal elongation characteristic in the range of 20 to 40% in the length direction and 40 to 80% in the width direction of the 5 kg static load elongation.

The nonwoven fabric may be made of nylon or polyester microfiber, specific examples of the polyester microfiber include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), and the like. Can be.

The raised protruding surface of the nonwoven fabric is distributed such that the linear density is in the range of 20 to 35 bone / 100 μm. When the brushed linear density is less than 20 bone / 100 micrometers or exceeds 35 bone / 100 micrometers, the appearance and feel of artificial leather are degraded.

The surface roughness of the artificial leather is 40㎛ or less. If the surface roughness of the artificial leather exceeds 40㎛ the brush is unevenly arranged to reduce the appearance and feel of artificial leather.

The microfibers constituting the nonwoven fabric preferably have a fineness range of 0.3 denier or less for the purpose of enhancing the feel of artificial leather.

Such artificial leather manufactures sea island-type fibers through a composite spinning process, manufactures nonwoven fabrics using island-in-the-sea fibers, impregnates the polymer elastomer with the nonwoven fabrics, and then removes sea components to make the fibers fine. It can be obtained through the process of raising the surface of the nonwoven fabric. Here, before impregnating the polymer elastic body in the nonwoven fabric, artificial leather may be obtained through a process of impregnating the polymer elastic body in the micronized nonwoven fabric after removing the sea component from the nonwoven fabric. However, the present invention is not necessarily limited thereto, and an artificial leather may be obtained by directly preparing microfibers through a spinning process, manufacturing a nonwoven fabric using microfibers, and impregnating a nonwoven fabric with a polymer elastic body.

Particularly, in the present invention, after the step of impregnating the polymer elastic body, by performing a process of rearranging the polymer elastic body on the surface of the nonwoven fabric to uniformly align the fibers, the linear density of the brush is in the range of 20 to 35 bone / 100 μm. The surface roughness of artificial leather can be adjusted to be less than 40㎛. The process of rearranging the polymer elastomer may be performed using a heated roll, and may be performed in any process after the impregnation of the polymer elastomer, and may be performed once or plural times.

The nonwoven fabric may be manufactured using a needle punch or a water jet punch after forming a web through a carding process and a cross lapping process of short fibers such as staple fibers. However, the present invention is not limited thereto, and a nonwoven fabric may be manufactured using a needle punch or a waterjet punch after forming a web through a spun bonding process of long fibers such as filaments.

In the method for producing artificial leather using the island-in-the-sea fiber, the island-in-the-sea fiber consists of a first polymer and a second polymer different from each other in dissolving property in a solvent.

The first polymer is a sea component dissolved in a solvent and eluted. The first polymer may be made of copolyester, polystyrene, or polyethylene, and is preferably made of copolyester having excellent solubility in an alkaline solvent. The copolyester is polyethylene glycol, polypropylene glycol, 1-4-cyclohexane dicarboxylic acid, 1-4-cyclohexanedimethanol, 1-4-cyclohexanedicarboxylate, in polyethylene terephthalate as a main component, 2-2-dimethyl-1,3-propanediol, 2-2-dimethyl-1,4-butanediol, 2,2,4-trimethyl-1,3-propanediol, adipic acid, metal sulfonate-containing ester unit Or a mixture of these may be used, but is not necessarily limited thereto.

The second polymer may be made of nylon or polyester which is not dissolved in a solvent and is an island component remaining in the solvent, and is not dissolved in an alkaline solvent. Examples of the polyester include polyethylene terephthalate (PET) or polytree. Methylene terephthalate (PTT) etc. are mentioned. In particular, the polytrimethylene terephthalate has a moderate carbon number between polyethylene terephthalate and polybutylene terephthalate, has an elastic recovery rate similar to that of polyamide, and is excellent in alkali resistance, and thus is preferable as a component.

Such islands-in-sea fibers are dissolved and eluted with the first polymer, which is a sea component, in a subsequent step, so that only the second polymer, which is an island component, remains to form ultrafine fibers. Therefore, in order to obtain desired microfine fibers, it is necessary to appropriately adjust the content of the first polymer as the sea component and the second polymer as the island component.

Specifically, in the island-in-the-sea fiber, it is preferable that the first polymer as the sea component is included in 10 to 60% by weight, and the second polymer as the island component is included in 40 to 90% by weight. When the first polymer of the sea component is included in less than 10% by weight, the content of the second polymer, which is a island component, may be increased so that the formation of microfine fibers may be impossible. This is because the amount of the first polymer that is eluted and removed is increased to increase the manufacturing cost. In addition, in the cross-sectional view of the island-in-the-sea fibers, the second polymer as the island component is arranged while being separated from each other, and after the first polymer as the sea component is eluted, the fineness of the second polymer as the island component is 0.3 denier or less. It is preferable to increase the feel of the ultrafine fibers.

Referring to the manufacturing method according to an embodiment of the artificial leather according to the present invention as described above are as follows.

First, island-in-the-sea fibers are produced.

The islands-in-the-sea fibers may be prepared in the form of staples, and in particular, after preparing a melt of each of the above-described sea component first polymer and island component second polymer, the composite may pass each melt through a predetermined spinneret. The filament may be obtained by spinning, the obtained filament may be stretched, a crimp is formed, heat set, and then cut.

At this time, the single yarn fineness of the filament obtained through the composite spinning is preferably 10 denier or less, because the single yarn fineness of the filament exceeds 10 denier to produce a non-woven fabric with island-in-the-sea fibers to manufacture artificial leather. This can be difficult when the carding process. More preferably, the single yarn fineness of the filament is in the range of 2 to 5 denier. Further, in the cross section of the filament, at least ten second polymers of the island component are arranged to be separated from each other, so that the fineness of the second polymer of the island component may be in a range of 0.3 denier or less. After elution, desired microfine fibers can be obtained, which is preferable.

The length of the island-in-the-sea fibers in the form of staples is preferably 20 mm or more because the carding process may be difficult when the nonwoven fabric is manufactured to manufacture artificial leather.

On the other hand, in the case of using a long fiber, such as filament in the manufacture of artificial leather does not perform the process of cutting the heat-fixed filament.

Next, a nonwoven fabric is manufactured using the island-in-sea fibers.

The nonwoven fabric is manufactured using a needle punch after forming a web through a carding process and a cross lapping process of the island-in-the-sea fibers in a staple state. The cross-lapping process is laminated to approximately 20 to 40 sheets to form a web.

Next, the polymer is impregnated with the nonwoven fabric.

This process consists of manufacturing a polymer elastomer solution, and then immersing the nonwoven fabric in the prepared polymer elastomer solution. The polymer elastomer solution may be prepared by dissolving or dispersing polyurethane in a predetermined solvent. For example, the polymer elastomer solution may be prepared by dissolving polyurethane in a dimethylformamide (DMF) solvent or dispersing polyurethane in a water solvent. . However, the silicone polymer elastomer may be used directly without dissolving or dispersing the polymer elastomer in a solvent.

In addition, the polymer elastomer solution may further include a pigment, a light stabilizer, an antioxidant, a flame retardant, a softening agent, a coloring agent, and the like, depending on the use.

Before immersing the nonwoven fabric in the polymer elastomer solution, the nonwoven fabric may be padded with an aqueous polyvinyl alcohol solution to stabilize the shape.

Here, the impregnated amount of the polymer elastic body impregnated in the nonwoven fabric by adjusting the concentration of the polymer elastomer solution, etc., considering that the content of the polymer elastomer contained in the final artificial leather is 20 to 30%, the polymer elastomer solution The concentration of is preferably adjusted in the range of 5 to 20% by weight. In addition, it is preferable to immerse the nonwoven fabric for 0.5 to 15 minutes while maintaining the temperature of the polymer elastomer solution in the concentration range of 5 to 20% by weight in the range of 10 to 30 ℃.

After the nonwoven fabric is immersed in the polymer elastomer solution, a step of coagulating the polymer elastomer impregnated in the nonwoven fabric in a coagulation bath is followed by washing in a washing tank. At this time, when the polymer elastomer solution is obtained by dissolving polyurethane in a dimethylformamide solvent, the coagulation bath is composed of a mixture of water and a small amount of dimethylformamide, and the polymer elastomer is solidified in the coagulation bath while being contained in the nonwoven fabric. Dimethylformamide may be allowed to escape into the coagulation bath, and the flushing bath may remove polyvinyl alcohol padded on the nonwoven fabric and remaining dimethylformamide from the nonwoven fabric.

Next, the sea component is removed from the nonwoven fabric impregnated with the polymer elastic body to make the fiber fine.

This step is a step of minimizing the fibers constituting the nonwoven fabric by eluting the first polymer as a sea component by using an alkaline solvent such as an aqueous caustic soda solution.

The heated rolls are then rotated on the nonwoven surface to perform thermal calendering. As such, the thermal calendering causes the polymer elastomer on the surface of the nonwoven fabric to be rearranged, thereby uniformly aligning the fibers on the surface of the nonwoven fabric fixed by the polymer elastomer. It can be formed uniformly.

The heating temperature of the roll is preferably maintained in the 80 ~ 200 ℃ range, because the thermal calendering effect can not be obtained when less than 80 ℃, the fiber of the nonwoven surface may be damaged if it exceeds 200 ℃.

Next, dyeing and post-treatment to complete the manufacture of artificial leather according to the present invention.

2. Examples and Comparative Examples

Example 1

A molten solution of a sea component is prepared by melting a copolyester in which 5 mol% of a metal sulfonate-containing polyester unit is copolymerized in a polyethylene terephthalate, which is a main component, and melts polyethylene terephthalate (PET). After preparing a melt of, filaments having a sea island-shaped cross section were obtained by complex spinning using 50 wt% of the melt of the sea component and 50 wt% of the melt of the island component, and the filaments were stretched at a draw ratio of 3.5. The crimp process was carried out so that the number of crimps was 15 / inch, heat-fixed at 130 ° C., and cut into 51 mm to prepare island-in-the-sea-fiber fibers in the form of staples.

Thereafter, after forming the web through the carding process and the cross lapping process, the non-woven fabric having a unit weight of 400 g / m ² and a thickness of 2.0 mm was manufactured using a needle punch.

Thereafter, the nonwoven fabric was padded with an aqueous polyvinyl alcohol solution having a concentration of 5% by weight, followed by drying. The dried nonwoven fabric was obtained by dissolving a polyurethane in a dimethylformamide (DMF) solvent and a polycondensate at 25 ° C and 25 ° C. After immersion in the urethane solution for 3 minutes, the polyurethane was coagulated in 15% by weight aqueous dimethylformamide solution and washed with water to impregnate the polyurethane with the nonwoven fabric.

Subsequently, the polyurethane-impregnated nonwoven fabric was treated with an aqueous solution of caustic soda at a concentration of 5% by weight to elute copolyester as a sea component on the nonwoven fabric, thereby minimizing the fiber with only polyethylene terephthalate (PET) as a sea component.

Thereafter, the surface of the nonwoven fabric was thermally calendered using a roll heated to 130 ° C., and the surface was brushed to have a final thickness of 0.6 mm using sandpaper # 300.

Thereafter, the dyes were dispersed in a high pressure rapid dyeing machine using a disperse dye, washed, dried, and treated with a softener and an antistatic agent to obtain artificial leather.

Example 2

In Example 1 described above, artificial leather was obtained in the same manner as in Example 1, except that the nonwoven fabric was immersed in a polyurethane solution at 13 wt% and 25 ° C. for 5 minutes.

Example 3

In Example 1 described above, artificial leather was obtained in the same manner as in Example 1, except that the nonwoven fabric was immersed in a polyurethane solution at a concentration of 16% by weight and 25 ° C. for 5 minutes.

Comparative Example 1

In Example 1 described above, artificial leather was obtained in the same manner as in Example 1, except that thermal calendaring was not performed after the polyurethane impregnation process.

Comparative Example 2

In Comparative Example 1 described above, artificial leather was obtained in the same manner as in Comparative Example 1, except that the nonwoven fabric was immersed in a polyurethane solution at a concentration of 4% by weight and 25 ° C. for 3 minutes.

Comparative Example 3

In Comparative Example 1 described above, artificial leather was obtained in the same manner as in Comparative Example 1, except that the nonwoven fabric was immersed in a polyurethane solution at a concentration of 21% by weight and 35 ° C. for 10 minutes.

The above, summarized the main process conditions of the Examples and Comparative Examples are shown in Table 1 below.

division
Polymer Elastomer Solution
Thermal calendar Concentration (% by weight) Temperature (℃) Immersion time (minutes) Example 1 10 25 3 Done Example 2 13 25 5 Done Example 3 16 25 5 Done Comparative Example 1 10 25 3 Do not perform Comparative Example 2 4 25 3 Do not perform Comparative Example 3 21 35 10 Do not perform

3. Experimental Example

Polymer elastomer content measurement

First, the artificial leather samples are prepared in a size of 10 cm x 10 cm, and then the weight of the artificial leather samples is measured.

Next, the sample is immersed in a beaker containing 1000 ml of a 100% concentration of dimethylformamide (DMF) solution, heated at 70 ° C. for 2 hours, and squeezed using mangol to sufficiently remove the polymer elastomer from the artificial leather sample. This process is repeated three times to completely remove the polymer elastomer from the artificial leather sample.

Next, the artificial leather sample is washed with running water several times, squeezed with mangrol to extract only the nonwoven fabric sheet, and then dried to measure the weight of the extracted nonwoven fabric sheet.

The polymer elastomer content is calculated by the method shown in Equation 1 below.

[Formula 1]

By the above method, the polymer elastic body content was measured in the artificial leather according to the Examples and Comparative Examples, and the results are shown in Table 2 below.

division Polymer elastomer content (% by weight) Example 1 21 Example 2 25 Example 3 30 Comparative Example 1 21 Comparative Example 2 15 Comparative Example 3 35

5kg static load elongation measurement

5 kg static load elongation was measured for each artificial leather sample according to the above-described examples and comparative examples. Elongation of artificial leather was measured by the following method, the results are shown in Table 3.

The measurement method is as follows.

Three test pieces each having a width of 50 mm and a length of 250 mm are taken in the longitudinal and transverse directions, respectively, and a marking line having a distance of 100 mm is drawn at the center thereof. This is 150 mm clamped, it is attached to a Maltensi fatigue tester, and it loads 49N (5 kgf) load slowly (including the lower clamp). Leave for 10 minutes under load and find the distance between the markings. Static load elongation is computed by the method of following formula 2.

[Formula 2]

Static load elongation (%) = ℓ1-100

[Wherein ℓ1: distance between mark lines 10 minutes after loading]

division Longitudinal elongation (%) Width Elongation (%) Example 1 27 55 Example 2 28 58 Example 3 24 49 Comparative Example 1 27 55 Comparative Example 2 41 82 Comparative Example 3 13 35

Linear density measurement

The linear density of each of the artificial leather samples according to the above-described examples and comparative examples was measured by the following method.

The surface of the artificial leather, which is a sample, is drawn in a random direction on a photograph taken with a scanning electron microscope, and the number of ultrafine fibers per 100 탆 (unit length) is first determined on the line. These measurements were made 10 times with even points on the photograph and then averaged.

The results are shown in Table 4 below.

division Linear density (bone / 100 μm) Example 1 28 Example 2 30 Example 3 25 Comparative Example 1 19 Comparative Example 2 39 Comparative Example 3 15

Surface roughness measurement

The surface roughness of each artificial leather sample according to the above-described examples and comparative examples was measured by the following method.

Carl Zeiss, a type of confocal laser scanning microscope (LSS) facility, LSM 5 PASCAL, a topography software package for LSM, or similar Measure by using LSM equipment. Specifically, by scanning the surface area range of the artificial leather (width 1,000㎛ x length 1,000㎛) with a laser to measure the centerline average roughness (Ra) value of 10 irregularities formed on the surface based on JIS B 0601 The ten point average roughness (Rz or SRa) of the surface S of the artificial leather is obtained from the arithmetic mean value. This ten point average roughness (Rz or SRa) is called surface roughness.

The results are shown in Table 5 below.

division Surface Roughness (㎛) Example 1 31 Example 2 24 Example 3 15 Comparative Example 1 50 Comparative Example 2 41 Comparative Example 3 13

Claims (11)

A nonwoven fabric composed of ultrafine fibers is impregnated with a polymer elastic body, the polymer elastic body is contained in 20 to 30% by weight, the linear density of the raised protruding surface is in the range of 20 ~ 35 bone / 100㎛, the surface of less than 40㎛ Artificial leather characterized by having a roughness. delete The method of claim 1, The artificial leather is artificial leather, characterized in that the 5kg static load elongation is 20 to 40% in the longitudinal direction, 40 to 80% in the width direction. The method of claim 1, The microfiber is made of polyethylene terephthalate, polytrimethylene terephthalate, or polybutylene terephthalate, the artificial elastic material, characterized in that the polymer elastomer is made of polyurethane. delete delete delete delete delete delete delete