KR20010104998A - Process for preparing two layer laid non-woven cloth - Google Patents

Abstract

The present invention relates to a method for producing a nonwoven fabric of a material such as artificial leather. According to the present invention, by using a chemical fiber entangled in a two-layer structure without the orientation, bound in a physical method and stabilized the form by a chemical method applied to industrial products or household goods to provide improved quality to consumers 2 Layered nonwoven products can be provided.

Description

Process for preparing two layer laid non-woven cloth

The present invention relates to a method for producing a two-layered nonwoven fabric (also referred to as "UM Type nonwoven fabric"), more particularly using chemical fibers, entangled in a two-layered structure without orientation, bound in a physical method, and formed in a chemical method. The present invention relates to a method for manufacturing a two-layer structured nonwoven fabric which can provide improved quality to consumers by stabilizing and applying to industrial products or household goods.

In general, non-woven cloth refers to a foam material in which natural fibers or artificial fibers SF or synthetic filaments are bonded by an adhesive, molten fibers or mechanical methods. As a method for producing such a nonwoven fabric, a process of making fibers into a sheet web by a wet method or a dry method, a process of joining a web by a mechanical or chemical method, and the like are known. For example, it is known to produce nonwoven webs by using emulsions of synthetic resins, using rollers, using synthetic resin powders, using fibers themselves as binders, but inferior in form stability and product strength. There is a weak problem that it is difficult to apply to various industrial products or household goods.

On the other hand, a mechanical method is known, such as a needle punch method, in which a needle is vertically punched on a web made of various fibers to make a plate. Such needle punch nonwoven fabrics are widely used as leather woolen fabrics, soundproofing fabrics for cars, floor coverings for carpets, etc., but mechanical strength and dimensional stability are poor, and strength is weak. In other words, punched cloth has a smaller strength and elongation than woven cloth, so that deformation in an arbitrary direction is severe. Therefore, the punched cloth must improve the strength as a cloth and stabilize the dimensions. Thus, a method of shrinking the web, bonding a binder to the punch cloth, inserting a yarn into the web, or punching the web over the woven fabric has been proposed.

Artificial leather manufactured by the method of the prior art as described above also has the disadvantage that it is inferior to the touch, density, elastic modulus, smoothness and the like compared to natural leather. Natural leather has a three-dimensional structure with high density, soft appearance and soft touch, but is difficult to mass-produce due to high product price. Therefore, attempts have been made in the nonwoven fabric manufacturing industry to manufacture artificial leather having characteristics similar to those of natural leather.

As a result of numerous studies and tests to develop a nonwoven fabric made of a material such as artificial leather, which has characteristics very similar to those of natural leather, the inventors have maintained the shape of the web not to be deformed using a layered structure, The present invention has been accomplished by discovering the surprising fact that mass production of a two-layered nonwoven fabric can be carried out at a low price by stabilizing the form by physical and chemical methods so as to uniformly bind to suppress peeling between layers and to approach natural leather.

The present invention relates to a method for producing a two-layer structured nonwoven fabric, comprising the following first, second and third steps.

First step: (a) obtaining a two-layer entangled sheet by carding, cross lapping and prepunching a P / N type or P / P type island-in-the-sea microfiber, and nylon and high shrink PET After mixing, passing through a bale opener or a fine opener, remixed in a hopper, carding, and then cross-wrapped in a sheet state to the two-layer entangled sheet obtained in the step (a), and bound by needle punching using surface punching. Obtaining a nonwoven fabric through step (b) of performing surface processing;

Second step: The nonwoven fabric obtained in the first step is eluted with a mixed solvent of phenol and carbon tetrachloride, then neutralized with a weak acid neutralizer, dehydrated with a manglow, and fixed at a temperature of 125 to 135 ° C. using a chamber dryer to form a shrinkable nonwoven fabric. Obtaining; And

Step 3: Impregnate the shrinkable nonwoven fabric obtained in the second step in 1-10% polyvinyl alcohol (PVA) and suppress the dehydration of left, middle and right dehydration using a Mangler roller, dry it with a cylinder device, and dry the three ball calender. Surface processing to obtain a two-layered nonwoven fabric.

Hereinafter, a method for manufacturing a two-layer structure nonwoven fabric according to the present invention will be described in detail for each step.

(1) 1 step process

(a) Step 1: Raw material ( Sea Island type microfiber) → carding → crosslapping → pre-punching → 2 laver sheet

(b) 2 step: Raw material (nylon + H.SPET) → → beets horn the other surface (carding) → → cross lapping the main punch (main punching) → surface treatment (calendering) → non-woven fabric

The raw material of the said 1st process uses P / N type or P / P type island-in-the-sea microfiber. The island-in-the-sea microfiber type P / N type is a regular nylon yarn of island component in a PET sea component, which is a kind of modified polymer, and a P / P type is a regular polyester yarn of island component in a PET sea component, which is a kind of modified polymer. The island-in-the-sea microfiber, the raw material of the first process, accounts for 70-50% of the total product ratio, and improves the surface effect as much as possible to maintain surface smoothness and uniformity, and is molded in the form of a two-layer entangled sheet to weakly bind it. To prevent formation.

The raw material of the second process is used for the purpose of the width shrinkage phenomenon, complementary properties, increase properties that can occur in the post-process by mixing nylon and high shrink polyethylene terephthalate (High Shrinkage PET), and also because the two raw materials are mixed Pass the bale opener, fine opener and remix in the hopper to ensure a good mix of raw materials.

The total ratio of nylon and highly shrinkable PET accounts for 30 to 50%, and the sheet is processed through a transfer molding process in a uniform state while minimizing neps (small combs) in the carding process. In a state of cross-lapping to the two-layer entangled sheet obtained in step 1 and bound in a needle punch.

Maintaining the basic physical properties of needle marks (N / T), needle marks (N / M), and peeling phenomenon in the binding process are important. Especially, in order to reduce elongation drift, the length and width in pre-punching are important. Curved punching was used to bind the direction at a constant rate. In the normal type of punching, the work proceeds by the operation of the outlet. In the surface punching, the work is internally curved, so the work is progressed by the stroke (the number of times bound by the needle). Bonding in surface punching reduces the drafting by forming the bond in X shape.

In the surface punching, the deviation between the mechanical direction and the CD direction of the tensile elongation is preferably about 1: 1.2. For example, (x: MD-y: CD = initial state): (X: MD-Y: CD = later state), (x: 1-y: 1.2 = after surface punching): (X: 1-Y : 1.9 = nonwoven fabric state), X: non-woven fabric MD direction tensile elongation (standard "1"), Y: nonwoven fabric CD direction tensile elongation, x: non-woven fabric CD direction elongation (x "1") , y: If the CD direction tensile elongation Y is more than 2.0 after passing through the surface punching, the draw ratio is high and the product is hard and the tension is excessively applied in one direction. In addition, if Y is 2 or less, it is a general type, and all products such as high density and synthetic leather are formed at 2 or less.

In addition, fixing heat at a temperature of about 150 to 155 ° C. in calendering during surface processing to maintain the nonwoven fabric density of 0.21 to 0.25 g / cm3 effectively prevents curing phenomenon occurring in the two-step process. . If the calendering temperature is less than 150 ° C., the heat transfer is insufficient to suppress the raised portion, so that the surface smoothness decreases, the thigh feels in touch, and the shrinkage phenomenon occurs in the post process (lacking heat setting). However, when the temperature exceeds 155 ° C, the touch may be hardened due to excessive high temperature, thereby deteriorating physical properties.

(2) two-step process

Solving → Neutralization → Washing → Dehydration → Drying

The density of the product after the one-step process is 0.21 to 0.25g / cm3 has a high density and constant left and right elongation compared to the general product. Generally, P / N type island-in-the-sea microfiber PET is not a regular polyester but a polyester made of modified polymer, so it is dissolved in NaOH 4% (95 ℃, 20min), but it is usually 15 at 20-25m / min in terms of productivity. It is preferable to adjust the concentration to 20%. In step 2, the solvent is caustic soda (NaOH).

During the elution process, some chemical reactions occur in the microfiber layer, so that the modified PET raw material is dissolved and only the microfiber nylon, which is a sea component, remains. The touch is very flexible and naturally the binding force is increased, the basic properties are maintained.

In addition, the strong alkali concentration is maintained at a temperature of 90 ° C. or higher to completely dissolve the modified polymer (PET) at about 15 to 20%, and during the neutralization reaction, it is continuously neutralized with a weak acid so that the pH is close to 7 (neutral). As the neutralizing agent usable in the present invention, formic acid (HCOOH), sulfuric acid (H2SO4), hydrochloric acid (HCl), aluminum sulfate (Al2SO4), glacial acetic acid (CH3COOH) and the like are preferable. The use of another acid as the neutralizing agent is not preferred because it is not uniform.

The washing process increases the recovery so that no residue remains. In dehydration, a manglow roller is used to prevent left, middle, and right deviations. In drying, the temperature can be set to 125 to 135 ° C using a chamber dryer to thermally set the fiber without deforming it. . When the drying temperature is 135 ° C. or higher, the fiber loses its intrinsic properties, deforms physical properties, and hardens the touch. In this way, the width shrinkage phenomenon during PVA impregnation, which is a three-step process, can be prevented in advance.

(3) three-step process

PVA impregnation → dehydration → drying → surface processing → UM nonwoven fabric

The three-stage process is to stabilize the nonwoven form. The shrinkable nonwoven fabric obtained in the second process is impregnated in 1 to 10% polyvinyl alcohol (PVA) and the temperature is kept constant at 80 ° C. to uniformly permeate the area optimally. In order to suppress the left, middle, and right dehydration variation using a manglow roller, and to maintain a constant dryness of the water by using a cylinder drying device to keep the moisture constant.

In addition, the surface processing used a vertical three-ball calender for the purpose of removing fine hairs from the surface, increasing the density, and maintaining the smoothness.As the working temperature is closely related to the weight, it is maintained at 150 ° C and 300g / m2 at 200 to 300g / m2. If above, select working condition at 160 ℃.

According to the present invention, a non-woven fabric which is a material of artificial leather is a process for manufacturing a non-woven fabric that gives a soft touch and a full taste to form the same three-dimensional structure as the form of natural leather to make a non-woven state and then dissolved using a chemical reaction And it is possible to maintain the shrinkage at the same time and to form a small voids by using the PVA impregnation process to be applied to the lightweight products in the post-process.

Hereinafter, the present invention will be described in detail based on Examples and Test Examples, but the technical scope of the present invention should not be understood as being limited thereto.

Example 1.

When 60% by weight of P / N type island-in-the-sea microfiber (corresponding to 180g / m2 when finished product weight is 300g / m2) is opened, cross-lapping and prepunching are carried out to obtain a two-layer entangled sheet, and a mixture of nylon and high shrinkage PET is bale After passing through an opener, the mixture is remixed in a hopper, carded, and cross-laminated onto the two-layered entangled sheet in a sheet state, and bound by needle punching using curved punching, and subjected to surface processing at 150 ° C. to obtain a nonwoven fabric. The resulting nonwoven fabric was eluted with caustic soda (NaOH), neutralized with formic acid with a neutralizing agent, dehydrated with a manglow, and fixed at a temperature of 130 ° C. using a chamber dryer to obtain a shrinkable nonwoven fabric. Subsequently, the shrinkable nonwoven fabric was impregnated in 5% polyvinyl alcohol (PVA) and the left, middle, and right dehydration deviations were suppressed using a Mangler roller while maintaining 80 ° C, dried with a cylinder device, and surface processed with a three-ball calender. A structural nonwoven was obtained.

In this manner, two types of nonwoven fabrics, such as shoe upper, were manufactured, which were 250 g / m 2 × 0.9 mm (first type) and 300 g / m 2 × 1.1 mm (second type).

Test Example 1.

The weight, thickness, tensile strength, tensile elongation, tear strength, bursting strength and air permeability of the nonwoven fabric obtained in Example 1 were tested according to the KS test method as shown in Table 1 below.

Relevant Standards by Test Items

Table 1.

The test results are shown in Table 2 below.

Table 2.

According to the test results of Table 2, the nonwoven fabric of the present invention had a 50g / m2 deviation and a thickness (thickness) relative to the weight, and thus the two types of nonwoven fabrics had a higher burst strength than 10% and a 75% decrease in air permeability. Structural density is increased, it can be confirmed that the resin layer can be applied to cost-saving and lightweight products in the post-processing operation.

Comparative Example 1.

General regular nonwoven fabric was prepared by the following process: raw material (PET, Nylon) → blended cotton → carding → cross lapping → prepunching → main punching → finishing punching → surface processing → general regular nonwoven fabric.

Comparative Example 2.

General high-density nonwoven fabric was produced by the following process: raw material (PET, Nylon) → blended cotton → carding → cross lapping → prepunching → main punching → needle punching nonwoven fabric → shrinkage treatment → dehydration drying → Calendering → High density nonwoven fabric.

Comparative results of the physical property changes of the nonwoven products of Comparative Examples 1 and 2 and the two types of nonwoven products of Example 1 are shown in Table 3 below.

Table 3.

From the results of Table 3, Example 1 (UM nonwoven fabric) was increased by 38 to 40% toward the MC (medical direction) in tensile strength compared to Comparative Example 1 (general product), Comparative Examples 1 and 2 is a single layer structure In contrast, Example 1 has a two-layer structure, and the binding state in the structure arrangement becomes more entangled in air permeability. In addition, the softness (softness) and cold taste (touchability) was found to be superior to Comparative Example 2 (general high density) by applying to a lightweight product in the post-process.

Comparison of general high density and non-woven fabrics of other companies.

Table 4.

According to the physical property data, the UM nonwoven fabric had better bursting strength and tensile strength than high density, and the binding state was dense in air permeability.

UM nonwoven fabric according to the present invention is softer than the general high-density product, and the structural arrangement is stable such as resilience, surface smoothness, uniformity, etc., so that it is easy to work in the post-process, cost reduction and mass production are possible, Products can be developed to meet diversified marketability and provide a framework that can be applied to industrial materials such as sports shoes, golf shoes, belts and car seats. It is also recognized as a product very close to natural leather, which can be developed at a lower price while several items can be developed.

Claims (4)

Method for producing a two-layer structure nonwoven fabric, characterized in that it comprises the following first step, second step and third step process: First step: a step (a) of obtaining a two-layer entangled sheet by carding, cross-lapping and prepunching a P / N type or P / P type island-in-the-sea microfiber, and mixing nylon and high shrink PET Through the bale opener or the fine opener, remixed in the hopper, carded, and cross-wrapped in a sheet state to the two-layer entangled sheet obtained in the above step (a), bound by needle punching using surface punching, and surface finishing. Obtaining a nonwoven fabric through step (b); Second step: The nonwoven fabric obtained in the first step is eluted with caustic soda (NaOH), neutralized with a weak acid neutralizer, dehydrated with a manglow, and fixed at a temperature of 125 to 135 ° C. using a chamber dryer to obtain a shrinkable nonwoven fabric. Obtaining; And Step 3: Impregnate the shrinkable nonwoven fabric obtained in the second step in 1-10% polyvinyl alcohol (PVA) and suppress the dehydration of left, middle and right dehydration using a Mangler roller, dry it with a cylinder device, and dry the three ball calender. Surface processing to obtain a two-layered nonwoven fabric. The method of manufacturing a two-layered nonwoven fabric according to claim 1, wherein a deviation between the MD direction and the CD direction of the tensile elongation in the first step of the surface punching is about 1: 1.2. The method for producing a two-layered nonwoven fabric according to claim 1, wherein the surface treatment is performed at a temperature of 150 to 155 캜 in the first step. The method of claim 1, wherein the neutralizing agent of the second step is formic acid (HCOOH), sulfuric acid (H2SO4), hydrochloric acid (HCl), aluminum sulfate (Al2SO4), or glacial acetic acid (CH3COOH).