KR102133029B1 - artificial leather and method of manufacturing the same - Google Patents

Abstract

The present invention relates to an artificial leather that is used in various applications and exhibits various and excellent properties. In an artificial leather in which a polymer elastic body is impregnated into a nonwoven fabric, the polymer elastic body is a urethane prepolymer obtained by reacting a polysiloxane diol and diisocyanate, It is a silicone-modified polyurethane having a viscosity of 60,000 to 150,000 cps (25°C) obtained by reacting with glycol and diisocyanate as a raw material, and relates to an artificial leather characterized by having a friction fastness rating of 3.0 or more.
According to the present invention, a silicone-modified polyurethane is impregnated as a polymer elastic material in a non-woven fabric forming an artificial leather, so that it is possible to improve the abrasion resistance, and at the same time improve physical properties, flexibility and elasticity of the salt resistance.
In addition, since the process of impregnating or coating the silicon separately is not required, it is possible to express the properties of the silicone and polyurethane without being separated while the process is simplified.

Description

Artificial leather and method of manufacturing the same}

The present invention is a polymer elastic body impregnated with a silicone-modified polyurethane. By manufacturing an artificial leather with a non-woven fabric, it relates to an artificial leather in which, in addition to abrasion resistance, physical properties such as otitis resistance and sensitivity quality such as flexibility and elasticity are improved.

Artificial leather is made by impregnating a polymer elastic body with a non-woven fabric formed of three-dimensional intertwined microfibers, and has a soft texture and unique appearance similar to natural leather, such as shoes, clothing, gloves, sundries, furniture and automobile interior materials. It is widely used in various fields.

Because artificial leather like this is used for various purposes, It should be excellent in terms of mechanical properties such as strength, tear strength, and abrasion resistance, but also must have excellent sensitivity quality such as flexibility, elasticity, soft touch, and excellent dyeability and high level of friction fastness that can be dyed in various colors and concentrations. Is required.

A general artificial leather impregnated with a polyurethane elastic body has been limited in improving physical properties such as abrasion resistance and stain resistance and flexibility and elastic properties.

Accordingly, there has been research and development to use silicone in addition to polyurethane as an elastic body to improve abrasion resistance.

According to Korean Patent Publication No. 2006-0125162, an artificial leather having improved wear strength by coating silicone rubber on a surface of an artificial leather formed of a nonwoven fabric impregnated with a polyurethane elastic body is described. However, the artificial leather has a problem in that the silicon layer and the polyurethane layer are clearly separated, so that each characteristic is realized separately, and a separate coating process is added, thereby complicating the manufacturing process.

According to Korean Patent Publication No. 2006-0007057, a coated fabric coated with a silicone component derived from an aqueous silicone emulsion and a polyurethane component derived from an aqueous polyurethane dispersion is described. However, although the coated fabric may form a uniform coating and reduce air permeability, it is difficult to improve abrasion strength required for long-term use in artificial leather using this technique.

According to Korean Patent Registration No. 0963147, a method of manufacturing an artificial leather by impregnating a silicone emulsion with a nonwoven fabric to form a softener-treated nonwoven fabric is described. When the fibers of the nonwoven fabric are softened by the silicone emulsion, the damage to the fibers can be minimized when the nonwoven fabric is densified by the shrinkage of the fibers, but there is no effect on improving the wear resistance.

As described above, attempts have been made to apply silicone in addition to polyurethane in artificial leather, and the development of artificial leather that satisfies various characteristics required by artificial leather is continuously required.

An object of the present invention is to provide an artificial leather formed of a non-woven fabric impregnated with silicone-modified polyurethane in order to solve the above problems and needs.

In order to solve the above problem, the present invention, in the artificial leather made of a non-woven fabric impregnated with a polymer elastic body, the polymer elastic body is a silicone-modified polyurethane having a viscosity of 60,000 ~ 150,000 cps (25 ℃), polysiloxane diol and diisocyanate Provided is an artificial leather characterized by being obtained by reacting a urethane prepolymer obtained by reaction, glycol and diisocyanate as a raw material.

In addition, the present invention, in a method for producing an artificial leather made of a nonwoven fabric impregnated with a polymer elastic body, reacting polysiloxane diol with diisocyanate to obtain a urethane prepolymer having a viscosity of 30,000 to 50,000 cps (25°C); Reacting the urethane prepolymer, glycol and diisocyanate to obtain a silicone-modified polyurethane having a viscosity of 60,000 to 150,000 cps (25°C); Diluting the silicone-modified polyurethane in dimethylformamide to prepare an impregnation liquid having a crude liquid viscosity of 2,000 to 3,000 cps (25°C); And impregnating the silicone-modified polyurethane with a non-woven fabric by immersing the non-woven fabric in the impregnation liquid.

According to the present invention, a silicone-modified polyurethane is impregnated as a polymer elastic body in a non-woven fabric forming an artificial leather, so that it is possible to improve the abrasion resistance, and at the same time improve physical properties, flexibility and elasticity of the salt resistance.

In addition, as the impregnating material of the present invention, the silicone-modified polyurethane has a siloxane structure in the polyurethane, and thus the process of simplifying the process is not separating the properties of the silicone and the polyurethane, since the process of impregnating the silicone separately or applying it to the nonwoven fabric is unnecessary It becomes possible to be expressed together without.

1 is a polymerization reaction formula of a silicone-modified polyurethane according to an embodiment of the present invention.

The present invention is to prepare a urethane prepolymer having an isocyanate at the end by reacting a diisocyanate having a siloxane structure with diisocyanate, and reacting the prepared urethane prepolymer, glycol, and isocyanate as raw materials to prepare a silicone-modified polyurethane. It relates to an artificial leather formed of a non-woven fabric impregnated with the prepared silicone-modified polyurethane.

As an example of the diol having the siloxane structure of the present invention, the structure of the polysiloxane diol is shown in Formula 1 below.

[Formula 1]

At this time, R is hydrogen or alkyl, and n is an integer from 1 to 30.

The polysiloxane diol has a weight average molecular weight (Mw) of 2,000 to 18,000, and a viscosity of 500 to 2,000 cps (25°C) is preferable because it can facilitate addition polymerization with isocyanate. At this time, if the weight average molecular weight (Mw) is less than 2,000, the length of the chain is shortened to increase the hardness, and if it exceeds 18,000, the soft segment is increased due to the long chain length, and elasticity in artificial leather is reduced. Can.

In addition, when n exceeds 30, the distance between the reactors increases due to the long chain of the siloxane, so that it is difficult to bond with each other and the reactivity may drop rapidly.

The isocyanate of the present invention is diisocyanate, 1,4-tetramethylene diisocyanate, 1,6 hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, cyclohexane-1,3- to 1,4-diisocyanate , 1-isocyanate-3-isocyanatemethyl-3,5,5-trimethylcyclohexane (isophorone diisocyanate), bis-(4-isocyanate cyclohexyl) methane (hydrogenated MDI), 2- to 4-isocyanate cyclohexyl- 2-isocyanate cyclohexylmethane, 1,3- to 1,4-tetramethylxylenediisocyanate, 2,4- to 2,6-diisocyanate toluene, 2,2-2,4- to 4,4'-di Phenylmethane diisocyanate, 1,5-naphthalene diisocyanate, xylene diisocyanate, diphenyl-4,4-diisocyanate, and the like.

The urethane prepolymer of the present invention is an isocyanate-terminated urethane prepolymer obtained by the reaction scheme shown in FIG. 1 by reacting a polysiloxane diol with diisocyanate according to a conventional method for preparing polyurethane, and has a viscosity of 30,000 to 50,000 cps (25°C. It is characterized by being.

When the viscosity is less than 30,000 cps, a rapid decrease in physical properties may occur due to a decrease in molecular weight, and when it exceeds 50,000 cps, the molecular chain of the urethane prepolymer becomes longer and the distance from the hydroxyl group for polymerization to the final polyurethane also increases, resulting in fluidity. However, sufficient polymerization may be difficult due to the high viscosity.

In addition, in the present invention, when the polysiloxane diol is reacted with diisocyanate, it is necessary that the ratio of the reaction is a ratio in which all the NCO groups are excessive, rather than all OH groups. In this way, by adjusting the ratio of the polysiloxane diol and diisocyanate to react, the resulting urethane prepolymer may have an isocyanate group terminal.

At this time, the molar ratio of the polysiloxane diol and diisocyanate is preferably 1:1.1 ~ 1:1.2.

By reacting the isocyanate-terminated urethane prepolymer, glycol, and diisocyanate as a raw material, a silicone-modified polyurethane having a viscosity of 60,000 to 150,000 cps (25°C) can be prepared.

At this time, if the viscosity is less than 60,000, a molecular chain of sufficient length may not be formed, which may cause deterioration of mechanical properties such as tear strength, thermal stability, and chemical properties such as hydrolysis resistance. If it exceeds 150,000, artificial leather In the polymer elastomer impregnation process, impregnation processability may be deteriorated due to high viscosity.

An example of the synthetic reaction scheme of the silicone-modified polyurethane described above can be represented by the following reaction scheme.

[Reaction formula]

At this time, R is each independently hydrogen or an alkyl group, R'is methylene diphenyl, n, m and o are each independently an integer of 1 to 30.

Carbon and silicon (Si) are located in the second and third cycles of Group 4 in the periodic table, and have similar properties to each other. Since the period 3 element has a larger electron orbit than the period 2 element, the covalent radius of carbon is 0.77 Å, whereas silicon is 1.17 Å, so the structure of siloxane (Si-O), which is a bond between silicon and oxygen, is larger than that of a common CC bond. Due to the covalent radii, the binding energy is strong and the coupling angle is large and long. Due to this, the silicone-modified polyurethane of the present invention having a siloxane structure can improve the flexibility and mechanical properties of artificial leather.

The present invention can be produced by including the step of immersing and impregnating a non-woven fabric forming an artificial leather in the impregnating liquid containing the silicone-modified polyurethane.

In general, artificial leather can be produced by immersing a non-woven fabric formed of three-dimensional interlocking microfibers in an impregnating liquid containing a polymer elastic body, impregnating the polymer elastic body to solidify, grinding, and brushing and dyeing.

In the present invention, an impregnating liquid in which the silicone-modified polyurethane is diluted in dimethylformamide can be used.

Hereinafter, the present invention will be specifically described by examples and comparative examples. However, the following examples and comparative examples are only for illustrating the present invention, and the present invention is not limited by the following examples, and other examples that are substituted and equivalent within the scope not departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in the art to which the present invention pertains.

[Production Example] (Preparation of urethane prepolymer)

An isocyanate-terminated silicone-modified urethane prepolymer was obtained by reacting 1.0 mol of polysiloxane diol having a weight average molecular weight (Mw) of 15,000 and a viscosity of 1,000 cps (25°C) with 1.2 mol of 4,4'-diphenylmethane diisocyanate. The obtained urethane prepolymer had a viscosity of 40,000 cps (25°C).

[Example 1]

Using the urethane prepolymer, the raw material conditions of Table 1 below were polymerized by a conventional polyurethane polymerization method to obtain a silicone-modified polyurethane, and the obtained silicone-modified polyurethane was diluted with dimethylformamide to prepare a crude liquid viscosity of 2,500 cps (25°C). To prepare an impregnating liquid, and immersing a nonwoven fabric in which polyester fibers (0.3 denier, 51 mm in length) are intersected in the impregnating liquid, and coagulating in an aqueous solution diluted with 20% by weight of dimethylformamide to form a fine porous material in the fiber structure. A nonwoven fabric impregnated with a layered silicone-modified polyurethane was prepared.

Thereafter, the surface of the impregnated nonwoven fabric was ground to cultivate fiber brushing on the surface to prepare artificial leather.

[Examples 2 to 3]

An artificial leather was manufactured in the same manner as in Example 1, except that Example 1 was performed under the conditions of Table 1 below.

[Comparative Examples 1-4]

An artificial leather was manufactured in the same manner as in Example 1, except that Example 1 was performed under the conditions of Table 1 below.

division urethane
Prepolymer
(Viscosity
@25℃) Polyurethane
Prepolymer PTMG*1 EG*2 Isocyanate*3 Polyurethane
Viscosity
(Viscosity
@25℃) Example 1 Manufacturing example
(40,000cps) 0.02 mole 0.408 mole 0.612 Mall 1.00 Mall 70,000cps Example 2 Manufacturing example
(40,000cps) 0.04 mole 0.416 mole 0.624 Mall 1.00 Mall 95,000cps Example 3 Manufacturing example
(40,000cps) 0.06 mole 0.424 Mall 0.636 Mall 1.00 Mall 130,000cps Comparative Example 1 - - 0.40 mole 0.60 Mall 1.00 Mall 80,000cps Comparative Example 2 - - 0.40 mole 0.60 Mall 1.00 Mall 80,000cps Comparative Example 3 Manufacturing example
(40,000cps) 0.08 mole 0.432 mole 0.648 Mall 1.00 Mall 200,000cps Comparative Example 4 Manufacturing example
(40,000cps) 0.10 mole 0.44 mole 0.66 Mall 1.00 Mall Gelation by rapid reaction is impossible to measure *Note 1) PTMG: Polytetramethylene glycol
2)EG: Ethylene glycol
3) 4,4'-diphenylmethane diisocyanate
4) In Comparative Example 2, 0.5 parts by weight of non-reactive silicone was added to 100 parts by weight of the polymer elastic body in the impregnating solution of the polymer elastic material of artificial leather.

The characteristics of the artificial leather produced in the above Examples and Comparative Examples were evaluated according to the following evaluation methods, and the results are shown in Table 2 below.

1. Otitis resistance (friction fastness) evaluation method

The otitis resistance of the artificial leather is evaluated by rating the color fastness to the inner ear.

For friction fastness, a sample cut from an artificial leather in a size of 2 x 15 cm is mounted on a friction fastness tester (model name DL-2007), and the white cotton cloth is placed on the surface of the sample to perform rubbing friction 10 times, and the contaminated white cotton cloth Compare the gray scale (Gray scale, KS K ISO 105-A05) to give a fastness rating. The pollution grade is 1 to 5, and the higher the number, the better the stain resistance.

(Based on pollution level,

5: No contaminants are visible, 4: Some contaminants are visible, but almost invisible, 3: Some contaminants are present and visible, 2: Some contaminants are slightly visible, 1: Some contaminants are quite severe )

2. Wear resistance (wear strength) evaluation method

The number of revolutions that the artificial leather ruptures and rubs on the floor while grinding a sample cut out of the artificial leather in a circular shape with a diameter of 10 cm with a CS-10 grinding wheel, a load of 1 Kg, and a rotation speed of 80 rpm up to 20,000 times in a Taber wear strength meter. Measure. The higher the number of rupture points, the higher the surface abrasion strength of artificial leather.

3. Flexibility evaluation method

The flexibility of the artificial leather is measured using the ST-300 softness meter. The flexibility grade is higher as the softness measurement length is higher.

4. Tensile elasticity

The tensile modulus of the artificial leather is measured in an Instron tensile recovery equipment. The higher the tensile modulus of elasticity (RT), the higher the recovery rate after tensile, and the better the elastic properties.

5. Viscosity

Using Brookfield's dial viscometer (model name RVT), select #6 for the spindle, immerse it in the measurement sample until the groove of the spindle is in contact, and then return to room temperature at a rate of 10 rpm (25 ℃) Measure in an atmosphere. When the gauge stops moving, multiply the scale reading by factor 1,000 to convert it into cps (centipose).

Wear strength
(Time to burst, times) Friction fastness
(Fastness rating, grade) flexibility
(mm) Tensile elasticity
(RT, %) Example 1 12,000 3.0 4.0 51.83 Example 2 18,600 3.5 4.2 56.77 Example 3 20,000 3.5 4.4 60.12 Comparative Example 1 8,500 2.5 3.4 38.18 Comparative Example 2 20,000 3.5 3.8 55.82 Comparative Example 3 - - - - Comparative Example 4 - - - -

In Comparative Example 3, due to the high viscosity of polyurethane, processability was poor, and thus it was impossible to manufacture artificial leather, and Comparative Example 4 was also gelled in the polymerization process, and thus, polyurethane that could be used as an elastic body could not be produced.

From Table 2, it can be seen that the artificial leathers according to Examples 1 to 3 are excellent in abrasion strength and friction fastness comparable to Comparative Example 2, which is particularly excellent in flexibility than Comparative Example 2. This is due to the use of a polyurethane that is converted into a flexible structure contained in a chain form in the molecular structure of the polyurethane rather than in a state in which the silicone molecules are dispersed in the polyurethane.

Claims (6)

In the artificial leather made of a non-woven fabric impregnated with a polymer elastic body,
The polymer elastic body is a silicone-modified polyurethane having a viscosity of 60,000 to 150,000 cps (25°C), and is characterized by being obtained by reacting a urethane prepolymer obtained by reacting a polysiloxane diol with diisocyanate, glycol, and diisocyanate as raw materials. Leather. According to claim 1,
Artificial leather, characterized in that the friction fastness rating of the artificial leather is 3.0 or more. According to claim 1,
The artificial leather is an artificial leather, characterized in that the tensile modulus is 50 to 70%. In the manufacturing method of artificial leather made of a non-woven fabric impregnated with a polymer elastic body,
Reacting the polysiloxane diol with diisocyanate to obtain a urethane prepolymer having a viscosity of 30,000 to 50,000 cps (25°C);
Reacting the urethane prepolymer, glycol and diisocyanate to obtain a silicone-modified polyurethane having a viscosity of 60,000 to 150,000 cps (25°C);
Diluting the silicone-modified polyurethane in dimethylformamide to prepare an impregnation liquid having a crude liquid viscosity of 2,000 to 3,000 cps (25°C); And
And impregnating the silicone-modified polyurethane with a nonwoven fabric by immersing the nonwoven fabric in the impregnation liquid. The method of claim 4,
In the step of obtaining the silicone-modified polyurethane, a method of manufacturing artificial leather, characterized in that the reaction of the diisocyanate and the urethane prepolymer and glycol in a 1:1 molar ratio. The method of claim 4,
The glycol is a method of manufacturing artificial leather, characterized in that polytetramethylene glycol and ethylene glycol.

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