KR20170002057A - Artificial leather and method for manufacturing the same - Google Patents

Abstract

The present invention relates to an artificial leather improved in shape stability during dyeing, wherein 100% elongation modulus is 30 to 90 Kgf / cm 2 polyurethane produced by polymerizing ethylene glycol and methylene bisbenzeneamine together with polyol and isocyanate as chain extenders As the impregnated artificial leather, when stretched at high temperature, the elongation percentage of the length is decreased and the shape stability is improved.

Description

TECHNICAL FIELD The present invention relates to an artificial leather and a method for manufacturing the same,

The present invention relates to an artificial leather improved in shape stability during dyeing, and more particularly, to an artificial leather in which a nonwoven fabric impregnated with a polyurethane excellent in heat resistance and modulus as an elastomeric polymer has improved dimensional stability during dyeing, and a method for producing the same .

The artificial leather is formed by impregnating a nonwoven fabric formed by three-dimensionally entangled microfine fibers into an elastomeric polymer, and has a soft texture and a unique appearance similar to natural leather, and is used in shoes, clothes, gloves, It is widely used in various fields.

A general artificial leather manufacturing method is a method of producing sea-island microfibers through non-woven fabric manufacturing processes such as needle punching, applying a polymeric elastomer, dissolving the marine components using an appropriate solvent to make microfibers, And dyeing and finishing with the desired color.

At this time, polyurethane is generally used as a polymer elastomer because it is suitable as a material of artificial leather with excellent elasticity and physical properties and gives a volume feeling to artificial leather.

Production of an artificial leather to which a polyurethane is applied as an elastic body is carried out by polymerizing a polyol, isocyanate or chain extender, which is a urethane raw material, in an organic solvent such as dimethylformamide to prepare a polyurethane, immersing the nonwoven fabric in the produced polyurethane Through the substitution reaction of water and dimethylformamide, a void is formed between the fiber and the polyurethane to have a microporous structure, and the microporous structure can cause the artificial leather to exhibit bulkiness. In addition, the size of the voids can be controlled by changing the rate in the substitution reaction to improve the bulkiness. This is commonly referred to as the wet method.

However, the polyurethane which is impregnated with the nonwoven fabric impregnates the fibers undergoes deformation at a temperature in the range of 120 to 140 ° C., and the shape is deformed at a temperature of 125 to 130 ° C., Can not be inhibited from occurring, resulting in deterioration of physical properties and appearance quality in artificial leather. Also, in the case of artificial leather products for automobiles, defects in appearance quality such as the shape change due to the melting of the polyurethane or the rearrangement of the molecular structure and the surface pressing phenomenon may occur in the hot compression molding process in the range of 120 to 150 ° C.

To solve this problem, a methylene bis-benzene amine (MBA) having a stable aromatic ring structure and excellent heat resistance can be used as a chain extender of a polyurethane. In this case, There is a problem that it is difficult to meet the mechanical properties required in the artificial leather products for automobiles and is not easy to use in the wet method.

Korean Patent Publication No. 0738178 (entitled "Heat-resistant synthetic polyurethane resin composition for artificial and synthetic leather, method of producing the same, and leather-like sheet)

An object of the present invention is to provide an artificial leather having improved shape stability during the dyeing process by polymerizing polyurethane which simultaneously satisfies both heat resistance and modulus as an elastic elastomer in artificial leather and a process for producing the same .

In order to solve the above problems, the present invention is an artificial leather comprising a nonwoven fabric made of sea-island microfine fibers impregnated with a polymeric elastomer and dyed, wherein the polymeric elastomer comprises a polyol; Isocyanate; And polyurethane polymerized with a raw material containing ethylene glycol and methylene bisbenzeneamine as a chain extender, wherein the polyurethane is contained in an amount of 10 to 40% by weight in the artificial leather.

According to the present invention, as the modified polyurethane having excellent heat resistance and modulus is impregnated into the elastic body from the artificial leather, the length elongation is reduced to less than 10% in the dyeing process, and thus the shape stability is improved.

The present invention relates to an artificial leather comprising a nonwoven fabric made of sea-island microfine fibers impregnated with a polymeric elastomer and dyed, wherein the polymeric elastomer comprises a polyol; Isocyanate; And polyurethane polymerized with a raw material containing ethylene glycol and methylene bisbenzeneamine as a chain extender, wherein the polyurethane is contained in an amount of 10 to 40% by weight in the artificial leather.

Wherein the polyol and the chain extender are reacted in an equimolar ratio to the polyol and the chain extender, wherein the polyol and the chain extender are selected from the group consisting of 0.4 to 0.6 moles of polytetramethylene glycol, 0.2 to 0.3 moles of ethylene glycol, and 0.2 to 0.3 moles of methylene bisbenzene amine To 0.3 mol, wherein the 100% elongation modulus is 30 to 90 Kgf / cm < 2 >.

In the production of the polyurethane of the present invention, it is preferable that the polyol serving as a soft segment has a weight average molecular weight (Mw) in the range of 500 to 3,500 g / mol by using an amorphous structure having a large molecular weight It can provide flexibility and filling in artificial leather.

In addition, MBA used as a chain extender can induce the effect of steric hindrance in the molecular structure by the structure of two cyclohexane rings to give a filling feeling of polyurethane, Rigid bonds due to urea reaction and impart excellent heat resistance characteristics.

On the other hand, mixing EG with a chain extender can complement the modulus which is lowered when MBA is used alone as a chain extender.

The present invention relates to a polyol and a chain extender comprising 0.4 to 0.6 moles of polytetramethylene glycol as a polyol, 0.2 to 0.3 moles of ethylene glycol as a chain extender, and 0.2 to 0.3 moles of the above-mentioned methylene bisbenzene amine, And a 100% elongation modulus of 30 to 90 Kgf / cm < 2 > prepared from the polyurethane, and impregnating and impregnating a nonwoven fabric made of sea-island microfine fibers into the impregnation solution containing the polyurethane Artificial leather can be produced.

In general, artificial leather can be manufactured by immersing a nonwoven fabric formed by three-dimensionally entangled microfine fibers into an impregnation liquid containing a polymer elastomer such as polyurethane, impregnating the polymer elastomer, coagulating, grinding, brushed and dyed.

In the present invention, the polyurethane of the present invention can be used in the impregnation solution.

Hereinafter, each step will be described in detail.

According to an embodiment of the present invention, there is provided a method of manufacturing an artificial leather having improved shape stability during dyeing, comprising the steps of: preparing an island in a sea type fiber through a composite spinning process; An ultrafine fiberization step including an elusion step of impregnating the nonwoven fabric with the prepared polyurethane as an elastic body, an elution step of removing the sea component of the sea-island fiber from the polyurethane-impregnated nonwoven fabric, Of the nonwoven fabric is dyed with a disperse dye, and the step of washing after the dyeing step is performed.

At this time, the microfiberization step may be performed before or after the elastomer application step.

The step of producing the sea-island fiber includes a step of composite spinning using a first polymer of a sea component dissolved and dissolved in a solvent and a second polymer of an island component remaining unresolved in a solvent .

The step of fabricating the nonwoven fabric may include a step of forming a web through a carding process and a cross lapping process in the form of staple fibers in a staple fiber state, Punching or water jet punching.

Optionally, the nonwoven fabric may be manufactured using a needle punch or a waterjet punch after a web is formed through a span bonding process in a filament fiber state.

In the step of applying the elastomer to impregnate the polyurethane, padding is performed after immersing the nonwoven fabric in the impregnation solution of the polyurethane, and the polyurethane is reacted with water and DMF (DiMethyl Formamide) Followed by coagulation.

Before the prepared nonwoven fabric is immersed in the polyurethane solution, the nonwoven fabric may be padded with a polyvinyl alcohol aqueous solution to stabilize the shape.

The polyurethane used for the impregnation solution is a polyol composed of 0.4 to 0.6 mol of polytetramethylene glycol as a polyol, 0.2 to 0.3 mol of ethylene glycol as a chain extender and 0.2 to 0.3 mol of the above-mentioned methylene bisbenzene amine, and isocyanate Is a polyurethane having a 100% elongation modulus of 30 to 90 Kgf / cm < 2 > prepared by polymerization in accordance with a conventional polymerization method of polyurethane at a molar ratio of 1: 1.

The polyurethane used as the impregnation solution is usually in a state in which the solid content of the polyurethane is diluted to 25 to 35% by weight in dimethylformamide.

The microfiberization step including an elution step for removing the sea component of the sea-island fiber includes a step of eluting the first polymer as a sea component by using an alkali solvent such as caustic soda aqueous solution.

According to another embodiment of the present invention, the nonwoven fabric manufacturing step includes a step of producing sea-island fibers through a composite spinning process, a step of producing a nonwoven fabric using the sea-island fibers, And an elastic body applying step of impregnating polyurethane into the nonwoven fabric from which the sea component has been removed.

According to another embodiment of the present invention, the step of producing a nonwoven fabric comprises the steps of: preparing microfine fibers having a fineness of 0.001 to 0.3 denier through composite spinning; preparing a nonwoven fabric using the microfine fibers; And an elastomer-imparting step of impregnating urethane.

In the present invention, the step of heat-shrinking and densifying the nonwoven fabric may be performed after the microfibrillating step.

The density of the nonwoven fabric can be improved by the above-mentioned heat shrinkage shrinkage, thereby increasing the napped density of the surface of artificial leather as a final product, thereby improving the surface appearance quality and improving the quality of sensibility of softness and softness.

In the densification step, the nonwoven fabric may be allowed to stay in hot water at 80 ° C or more for 1 minute or more and compressed by a thermal calender.

The step of preparing the dye comprises mixing yellow, red and blue disperse dyes.

The dispersion dye may be one comprising at least one dye selected from benzene azo based dispersion dyes, heterocyclic azo based dispersion dyes, anthraquinone based dispersion dyes and condensed dispersion dyes.

The step of dyeing the polymeric elastomer-impregnated nonwoven fabric with the disperse dye may be carried out using a salt solution to which the disperse dye and the additive are added.

Wherein the saline solution comprises 1 to 20% owf (on the weight of fiber) of yellow disperse dye, 1 to 20% owf red dispersion dye, 1 to 20% owf blue dispersion dye and 1 to 20% owf By including a black disperse dye, the color of the black line is expressed, and the total content of the disperse dye may be 3 to 60% owf.

In the dyeing step, the temperature of the saline solution may be maintained at 80 to 140 DEG C and dyeing may be performed for 20 to 60 minutes. If the temperature of the saline solution exceeds 140 ° C or the dyeing is performed for more than 60 minutes, the cost may increase, which is not preferable.

A reduction washing process for removing unfixed dyes or impurities on the surface of the dyed artificial leather can be further performed. The reduction washing process may be performed at 40 to 100 ° C for 10 to 30 minutes. Through the reduction washing process, the color of the artificial leather can be made clearer.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It is to be understood, however, that the following examples and comparative examples are given for the purpose of illustration only and are not to be construed as limiting the scope of the present invention. It is to be understood that within the scope of the present invention, It will be apparent to those skilled in the art to which the present invention pertains.

[Example 1]

0.6 mol (Mw: 2,000) of polytetramethylene glycol (PTMG) and 4,4'-diphenylmethane diisocyanate (MDI) in the presence of dimethylformamide (DMF) as a first stage using a conventional polyurethane polymerization method. , 0.2 mol of ethylene glycol (EG) and 0.2 mol of 4,4'-methylene bisbenzene amine (MBA) were added as the second stage, and 0.4 mol of MDI and DMF were further added as the third stage to effect addition polymerization .

The polyurethane used as the impregnation solution, in which the polymerized polyurethane solid content was diluted to 30% by weight in dimethylformamide (DMF), was prepared.

The 100% elongation modulus of the polymerized polyurethane was as shown in Table 1 below.

Polyester copolymerized with 5 mol% of a polyester copolymer containing polyethylene terephthalate as a component and containing a metal sulfonate as a sea component was co-spun to obtain a weight ratio of a component: Denier sea shell filaments were produced. The sea shell filaments were stretched at a draw ratio of 3.1 times and subjected to a crimp process so as to have a crimp number of 13 pieces / inch, followed by heat setting at 130 ° C and cutting to 51 mm.

The nonwoven fabric having a basis weight of 230 g / m < 2 > was prepared by forming the web through the carding process and the cross-lapping process and then needle punching.

The nonwoven fabric was immersed in an elastomer impregnating solution prepared by diluting the polyurethane used in the prepared impregnating solution with 150% by weight of dimethylformamide relative to the weight of the polyurethane used in the prepared impregnating solution, to 80% of the thickness of the nonwoven fabric After padding, it was solidified in an aqueous solution of 20% by weight of dimethylformamide and dried in a drier at 120 DEG C for 10 minutes to obtain an impregnation containing 20% by weight of the polyurethane in the nonwoven fabric.

The surface of the impregnation was then buffed with a sandpaper 320 mesh using a buffing machine to form a nap on the surface.

The napped nonwoven fabric was dyed under the following dyeing conditions.

<Conditions for dyeing>

1) Dye ratio

 - Black disperse dye (Huntsman) 5.5% o.w.f. (on the weight of fiber)

 Yellow disperse dye (Huntsman) 11% o.w.f.

 - Red disperse dye (Huntsman) 2.5% o.w.f

 - Black disperse dye (Dyestar Co.) 11% o.w.f.

2) Leveling agent: PEO Alkyl Amine Sulfate Type Compound compound 2.5% o.w.f.

3) Bath softener (D-1500): 3 g / L

4) Acid: Acetic acid 1 g / L

5) Bath (additive weight: solvent weight): 1:30

6) Dyeing temperature and time: 130 占 폚 and 60 minutes

After the dyeing, the mixture was subjected to reduction washing with a reducing washing solution of sodium hydroxide and sodium hydrosulfite, followed by washing with water and drying to prepare artificial leather.

[Example 2]

An artificial leather was produced in the same manner as in Example 1, except that the polyurethane used in the impregnation solution in Example 1 was prepared as shown in Table 1 below.

[Example 3]

An artificial leather was produced in the same manner as in Example 1, except that the polyurethane used in the impregnation solution in Example 1 was prepared as shown in Table 1 below.

[Example 4]

An artificial leather was produced in the same manner as in Example 1, except that the polyurethane used in the impregnation solution in Example 1 was prepared as shown in Table 1 below.

[Comparative Example 1]

An artificial leather was produced in the same manner as in Example 1, except that the polyurethane used in the impregnation solution in Example 1 was prepared as shown in Table 1 below.

[Comparative Example 2]

An artificial leather was produced in the same manner as in Example 1, except that the polyurethane used in the impregnation solution in Example 1 was prepared as shown in Table 1 below.

[Comparative Example 3]

An artificial leather was produced in the same manner as in Example 1, except that the polyurethane used in the impregnation solution in Example 1 was prepared as shown in Table 1 below.

The properties of the artificial leather prepared in the above Examples and Comparative Examples were evaluated according to the following evaluation methods, and the results are shown in Table 1 below.

<Evaluation method>

1. 100% elongation modulus

The polyurethane is molded into a dry film having a thickness of 0.1 mm, and the molded film is cut to a size of 1 cm in length and 20 cm in length, and a length of 10 cm in the longitudinal direction is positioned in the center of the film. After attaching a film with a length of 10 cm to the tensile strength meter, apply force and measure the force applied when the marked part is stretched to 20 ㎝.

2. Length elongation after dyeing (%)

(Length after dyeing - length before dyeing) x 100 / length before dyeing

3. Measurement method of weight average molecular weight

The samples were analyzed by gel permeation chromatography (GPC) (RI-8000, Tosoh) using tetrahydrofuran as the mobile phase (flow rate 1 mL / min) and TSKgel super HM-L, TSKgel super HM- Passed through a column in which TSKgel super HM-N (manufactured by Tosoh Co.) is connected in series, and the temperature is measured under the condition that the temperature of the column oven is 40 ° C.

division Polyurethane polymerization raw material cost (moles) Polymerized
Polyurethane
Properties Polyurethane
Impregnation amount
(weight%) After dyeing
Length elongation
(%) PTMG EG MBA MDI 100% height
Modulus
(Kgf / cm2) Example 1 0.6 0.2 0.2 1.0 35 20 8.5 Example 2 0.5 0.25 0.25 1.0 55 20 5.4 Example 3 0.4 0.3 0.3 1.0 70 20 3.2 Example 4 0.6 0.2 0.2 1.0 30 30 9.6 Comparative Example 1 0.6 0.4 0.0 1.0 30 20 15.3 Comparative Example 2 0.5 0.5 0.0 1.0 48 20 11.2 Comparative Example 3 0.6 0.0 0.2 1.0 - - - Remark: The Mw of the PTMG of Example 4 is 3,000.
The polymerized polyurethane of Comparative Example 3 was gelled and used as the polyurethane used as the impregnation solution
It was impossible.

From the examples in the above Table 1, it can be seen that the polyurethane-containing artificial leather produced by using MBA and EG as chain extenders simultaneously in the scope of the present invention exhibits less than 10% elongation after dyeing, .

Claims (4)

An artificial leather comprising a nonwoven fabric made of sea-island microfine fibers impregnated with a polymeric elastomer and dyed,
The polymeric elastomer includes polyol; Isocyanate; And a polyurethane polymerized with a raw material containing ethylene glycol and methylene bisbenzene amine as a chain extender,
Wherein the polyurethane is contained in an amount of 10 to 40% by weight in the artificial leather. The method according to claim 1,
The polyurethane is produced by reacting an isocyanate with a polyol and a chain extender at an equivalent molar ratio,
Wherein the polyol and the chain extender are in a ratio of 0.4 to 0.6 mol of polytetramethylene glycol, 0.2 to 0.3 mol of ethylene glycol and 0.2 to 0.3 mol of methylene bisbenzene amine. 3. The method of claim 2,
Wherein the polytetramethylene glycol has a weight average molecular weight of 500 to 3,500. The method according to claim 1,
Wherein the polyurethane has a 100% elongation modulus of 30 to 90 Kgf / cm 2.