WO2008026895A1

WO2008026895A1 - Nonflammable artificial leather and the preparation method of the same

Info

Publication number: WO2008026895A1
Application number: PCT/KR2007/004202
Authority: WO
Inventors: Yong-Gu Kweon; Jin-Won Jun; Chang-Young Jung
Original assignee: Lg Chem. Ltd.
Priority date: 2006-08-31
Filing date: 2007-08-31
Publication date: 2008-03-06

Abstract

Provided are a nonflammable artificial leather including: a nonflammable soft sheet material layer having polysiloxane, an inorganic hydroxide, a Pt compound and an inorganic filler; and a nonflammable fiber layer, and preparation method of the nonflammable artificial leather. The nonflammable artificial leather has flame-retardant properties with VO grade flame retardancy or higher since the artificial leather is incombustible at a high temperature, blocks ignition and prevents flame transmission, and is environmentally friendly since the artificial leather does not emit dioxine and black smoke that are harmful to humans. Thus, the nonflammable artificial leather can be applied to various products such as artificial leather covering seats of various transportation vehicles, interior materials for walls of buildings such as incombustible materials and insulating materials, clothing requiring nonflammability, play mats for kids and so on.

Description

NONFLAMMABLE ARTIFICIAL LEATHER AND THE PREPARATION METHOD OF

THE SAME

TECHNICAL FIELD

The present invention relates to a nonflammable artificial leather and a preparation method of the same, and more particularly, to a nonflammable artificial leather which has flame-retardant properties with VO grade flame retardancy or higher since the artificial leather is incombustible at a high temperature, blocks ignition and prevents flame transmission, and is environmentally friendly since the artificial leather does not emit dioxine and black smoke that are harmful to humans, and a preparation method of the same.

BACKGROUND ART

Artificial leather can be used to replace natural leather as interior materials for transportation means such as cars and trains, and walls of buildings. Recently, there has been a great demand for the artificial leather since artificial leather can be manufactured at low cost with developments in technology.

However, conventional artificial leather is generally manufactured from combustible materials such as organic compounds, and thus the artificial leather burns well and emits harmful gases, particularly dioxine, when burned. In order to solve these problems, much research on flame-retardant compositions that can be used for artificial leather has been carried out. Korean Patent Publication No. 2002-0047050 discloses a flam-retardant UV and UV/moisture curable silicon composition. The flame-retardant silicon composition curable by UV irradiation to an elastomer includes an acrylate-based functional group, a reactive silicon resin component comprising a reactive polyorganosiloxane, an inorganic filler, a photoinitiator compound, Pt, alumina hydroxide, etc. Japanese Patent Publication No. 2005-188610 discloses a flame-retardant and thermal conductive silicon molding in a sheet form including organopolysiloxane having an alkenyl group connected to a silicon atom, a thermal conductive filler, organo hydrogen polysiloxane having a hydrogen atom connected to a silicon atom, a platinum group metal catalyst for addition reaction and a flame-retardant agent.

However, the composition or moldings using the composition disclosed in the publications include organic compounds, and thus flame-retardant properties are not sufficient and emission of dioxine cannot be completely prevented when burned. In addition, artificial leather having beneficial effects to humans such as artificial leather that emits far infrared rays has not been developed.

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL PROBLEM

The present invention provides a nonflammable artificial leather which is not incombustible at a high temperature, blocks ignition, prevents flame transmission, and does not emit harmful dioxine and black smoke.

The present invention also provides a nonflammable artificial leather having sound-absorbing properties.

The present invention also provides a method of preparing the nonflammable artificial leather.

The present invention also provides a method of preparing the nonflammable artificial leather having sound-absorbing properties.

TECHNICAL SOLUTION

According to an aspect of the present invention, there is provided a nonflammable artificial leather comprising: a nonflammable soft sheet material layer including polysiloxane, an inorganic hydroxide, a Pt compound and an inorganic filler; and a nonflammable fiber layer

According to another aspect of the present invention, there is provided a nonflammable artificial leather having sound-absorbing properties comprising: the nonflammable artificial leather as above; and a silicon foam sheet adhered to one surface of the nonflammable artificial leather.

According to another aspect of the present invention, there is provided a method of preparing a nonflammable artificial leather, the method comprising: (a) preparing a primary material by mixing polysiloxane, an inorganic hydroxide and an additive including a processing aid and processing the mixture;

(b) preparing a final material by mixing the primary material, an inorganic filler, and a Pt compound and removing bubbles; (c) preparing a nonflammable soft sheet by processing the final material to form a sheet and curing the resultant product by air drying; and

(d) coating or impregnating the bottom surface of the nonflammable soft sheet with a flame-retardant adhesive to adhere a nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer, and curing the resultant product by air drying. According to another aspect of the present invention, there is provided a method of preparing a nonflammable artificial leather having sound-absorbing properties, the method comprising:

(a) preparing a primary material by mixing polysiloxane, an inorganic hydroxide and an additive including a processing aid and processing the mixture; (b) preparing a final material by mixing the primary material, an inorganic filler, and a Pt compound and removing bubbles;

(c) preparing a nonflammable soft sheet by processing the final material to form a sheet and curing the resultant product by air drying;

(d) coating or impregnating the bottom surface of the nonflammable soft sheet with a flame-retardant adhesive to adhere a nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer, and curing the resultant product by air drying; and.

(f) forming silicon foam on the bottom surface of the nonflammable fiber layer, and curing the resultant product by air drying.

ADVANTAGEOUS EFFECTS

The nonflammable artificial leather according to the present invention has flame-retardant properties with VO grade flame retardancy or higher since the artificial leather is incombustible at a high temperature, blocks ignition and prevents flame transmission, and is environmentally friendly since the artificial leather does not emit dioxine and black smoke that are harmful to humans. Thus, the nonflammable artificial leather can be applied to various products such as use as artificial leather covering seats of various transportation vehicles, interior materials for walls of buildings such as incombustible materials and insulating materials, clothing requiring nonflammability, play mats for kids and so on.

DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows a structure of a nonflammable artificial leather according to an embodiment of the present invention.

FIG. 2 schematically shows a structure of a nonflammable artificial leather according to an embodiment of the present invention.

FIG. 3 schematically shows a structure of a nonflammable artificial leather according to an embodiment of the present invention.

FIG. 4 schematically shows a structure of a nonflammable artificial leather according to an embodiment of the present invention.

FIG. 5 schematically shows a structure of a nonflammable artificial leather according to an embodiment of the present invention. FIG. 6 shows a graph illustrating far infrared ray emissivity of a nonflammable artificial leather according to an embodiment of the present invention.

BEST MODE Hereinafter, the present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

A nonflammable artificial leather according to the present invention includes a soft sheet material layer having polysiloxane, an inorganic hydroxide, a Pt compound and an inorganic filler; and a nonflammable fiber layer. The polysiloxane allows the soft sheet material layer to have flame-retardant properties and functions a liquid base material in which the inorganic hydroxide and the Pt compound are mixed. The viscosity of the polysiloxane may be from 1 ,000 to 500,000 cps, and preferably from 10,000 to 200,000 cps. When the viscosity of the polysiloxane is less than 1 ,000 cps, the process is not properly performed since the polysiloxane becomes oil-like. On the other hand, when the viscosity is greater than 500,000 cps, the polysiloxane is not properly distributed, and thus the artificial leather cannot have desired properties. The inorganic hydroxide improves flame-retardant properties of the soft sheet material layer. Any hydroxide of metals may be used without limitation, for example, aluminum hydroxide, magnesium hydroxide, and combinations thereof may be used.

The inorganic filler increases viscosity and weight of the liquid mixture as well as improves flame-retardant properties. Examples of the inorganic filler include CaCO₃, SiO₂, AI₂O₃, Fe₂O, CaO, MgO, K₂O, Na₂O and combinations thereof. Due to the presence of the inorganic filler, the nonflammable artificial leather can emit far infrared rays which are beneficial to humans.

The Pt compound may be chloroplatinic acid or phosphate-based platinum. The Pt compound is plasticized by being uniformly dispersed using an organic solvent such as alcohol, isopropyl alcohol, benzene, and xylene to have desirable self-extinguishing propertyproperties. Examples of the Pt compound include Pt{P(CH₃)₃}₄, Pt(P(C₄Hg)₃J₄, Pt{P(OCH₃)₃}₄, Pt(P(OC₆Hs)₃J₃, Pt(P(C₆H₅)₃}₃, Pt(P(OC₆H₅)₃}₄, Pt(P(C₆Hs)₃J₄, Pt(P(C₆H₅)(C₂Hs)₂J₄, and Pt(P(OC₆H₅)(OC₂Hs)₂J₄. The polysiloxane, the inorganic hydroxide, the Pt compound, and the processing aid may be mixed in a desired ratio in respect to flame-retardant properties and flexibility of the soft sheet material layer. Accordingly, the ratio of the polysiloxane: the inorganic hydroxide: the Pt compound: the processing aid may be 2 to 97% by weight: 1 to 50 % by weight: 0.01 to 0.5 % by weight:1.0 to 10.0 % by weight. When the amount of the polysiloxane is below the range shown above, flexibility is insufficient, and thus costs for manufacturing sheets increase due to a number of manufacturing processes and sheets are too stiff to be commercialized. On the other hand, when the amount of the polysiloxane is above the range shown above, chemical reactions of cross-links take too much time and degradation may occur since cross-links are disconnected. The nonflammable soft sheet material layer may include 2 to 97% by weight of the polysiloxane, 1 to 50% by weight of the inorganic hydroxide and 0.01 to 0.5% by weight of the Pt compound.

Preferably, the nonflammable soft sheet material layer may include 45 to 97% by weight of the polysiloxane, 1 to 35% by weight of the inorganic hydroxide and 0.01 to 0.5% by weight of the Pt compound.

The inorganic filler is mixed with a composition including the polysiloxane, the inorganic hydroxide, the Pt compound, and the processing aid to increase weight and thickness of the soft sheet material layer and reinforce flame-retardant properties. The amount of the inorganic filler may be in the range of 1 to 30 % by weight, and preferably 5 to 20 % by weight based on the total weight of the nonflammable soft sheet material layer. When the amount of the inorganic filler is less than 1 % by weight, strength of the products may decrease and degradation may occur, and thus value of the product may decrease. On the other hand, when the amount of the inorganic filler is greater than 30 % by weight, sheets are formed to be too stiff.

Thus, the nonflammable soft sheet material layer may include 45 to 97% by weight of the polysiloxane, 1 to 35% by weight of the inorganic hydroxide, 0.01 to 0.5% by weight of the Pt compound, and 1 to 30 % by weight of the inorganic filler, and preferably, 45 to 97% by weight of the polysiloxane, 1 to 35% by weight of the inorganic hydroxide, 0.01 to 0.5% by weight of the Pt compound, and 1 to 30 % by weight of the inorganic filler.

The nonflammable fiber layer which supports the soft sheet material layer, and improves mechanical properties such as tensile strength and tear strength is fundamentally formed of a nonflammable fiber. Materials that can be used as the nonflammable fiber layer may be a carbon fiber, a basalt fiber, a flame-resistant cotton fiber, an alumina fiber, a silica fiber or combinations thereof, but are not limited thereto. More specifically, the carbon fiber may include at least 85% of carbon to have high strength and elasticity of the carbon fiber and not to deform at a temperature from 1 ,800 to 3,500⁰C . The basalt fiber may be a nonflammable woven type fiber designed not to deform at 900⁰C and having excellent adhesion properties, anion generating properties, far infrared ray emitting properties, antibiotic properties, and deodorizing properties. The cotton fiber includes at least 99% cotton, and may have nonflammable properties by flame-retardant treatment. The nonflammable artificial leather including the soft sheet material layer and the nonflammable fiber layer according to the present invention may further include a polyurethane coating layer on the soft sheet material layer. The polyurethane coating layer which provides a natural leather-like touch to the artificial leather improves mechanical properties such as abrasion resistance and scratch resistance required for the artificial leather. The thickness of the polyurethane coating layer may be from 0.01 to 0.10 mm. When the thickness of the polyurethane coating layer is less than 0.01 mm, mechanical properties such as abrasion resistance and scratch resistance are not sufficiently improved. On the other hand, when the thickness of the polyurethane coating layer is greater than 0.10 mm, flame-retardant properties may be decreased and harmful materials may be emitted when burned.

The nonflammable artificial leather may further include additional layers such as an UV coating layer and an ink coating layer, or a primer layer such as a ceramic layer in order to improve properties of the artificial leather.

The nonflammable artificial leather including the soft sheet material layer and the nonflammable fiber layer may further include a foam layer formed of an aluminum fiber and a silica fiber on the bottom surface of the nonflammable artificial leather. The foam layer increases the thickness of the nonflammable artificial leather and improves comfort. The nonflammable artificial leather including the foam layer can be applied to play mats for kids requiring nonflammability.

Accordingly, the nonflammable artificial leather of the present invention may have structures as described below.

The nonflammable artificial leather may have the structure of a surface-treated material layer formed of polyurethane/ a nonflammable soft sheet material layer/ a nonflammable fiber layer formed of carbon fiber as shown in FIG. 1.

The nonflammable artificial leather may have the structure of a surface-treated material layer formed of polyurethane/ a nonflammable soft sheet material layer/ a nonflammable fiber layer formed of basalt fiber as shown in FIG. 2. The nonflammable artificial leather may have the structure of a surface-treated material layer formed of polyurethane/ a nonflammable soft sheet material layer/ a nonflammable fiber layer formed of flame-resistant cotton fiber as shown in FIG. 3.

The nonflammable artificial leather may have the structure of a surface-treated material layer formed of polyurethane/ a nonflammable soft sheet material layer/ a nonflammable fiber layer formed of alumina and silica fiber as shown in FIG. 4.

The nonflammable artificial leather may have the structure of a surface-treated material layer formed of polyurethane/ a nonflammable soft sheet material layer/ a nonflammable fiber layer/ a foam layer formed of alumina and silica fiber as shown in FIG. 5. The structure of the nonflammable artificial leather according to the present invention is not limited thereto, and the nonflammable artificial leather may have various structures having nonflammable properties in addition to the structures described above. The present invention also provides a nonflammable artificial leather having sound-absorbing properties including: the nonflammable artificial leather; and a silicon foam sheet adhered to one surface of the nonflammable artificial leather. The silicon foam sheet absorbs sound and thus may be used as a sound-absorbing material. The silicone foam sheet is prepared by foaming and molding silicon, and any material that can absorb sound can also be used without limitation of the material and structure. The silicon foam may be obtained by reacting a siloxane having a hydroxyl group with a siloxane having a hydrogen group using a Pt catalyst and emitting hydrogen gas, but the method of forming the silicon foam is not limited thereto, and any method of foaming known in the art may be applied.

A method of preparing a nonflammable artificial leather of the present invention will now be described in more detail.

The method of preparing the nonflammable artificial leather includes:

(a) preparing a primary material by mixing polysiloxane, an inorganic hydroxide and an additive including a processing aid and processing the mixture;

(b) preparing a final material by mixing the primary material, an inorganic filler, and a Pt compound and removing bubbles;

(c) preparing a nonflammable soft sheet by processing the final material to form a sheet and curing the resultant product by air drying; and (d) coating or impregnating the bottom surface of the nonflammable soft sheet with a flame-retardant adhesive to adhere a nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer, and curing the resultant product by air drying. The polysiloxane, the inorganic hydroxide and the Pt compound, the processing aid in operation (a) are the same as those described with regard to the nonflammable artificial leather.

In operation (a), the polysiloxane, the inorganic hydroxide and the additive including the processing aid are mixed in an appropriate ratio to prepare a composition. The mixing may be performed by extruding and mixing devices, and additional materials such as titanium oxide and iron oxide may further be added to the composition to color the composition. The prepared composition is referred to as a primary material.

Then, the primary material prepared in operation (a) is mixed with an inorganic filler and a Pt compound, and bubbles are removed to prepare a final material. The inorganic filler is described above with regard to the nonflammable artificial leather. The primary material has viscosity of from 1 ,000 to 500,000 cps. When the viscosity is within the range, bubbles make pores on the surface of the products and thickness variation may occur, and thus the bubbles need to be completely removed using a bubble removing apparatus.

In operation (c), the final material is processed to form a sheet and the resultant product is cured by air drying to prepare a nonflammable soft sheet. More specifically, the final material is dispersed using a coating knife or a two-roll mill while the thickness of the final material layer is controlled, and plasticized. The final material is processed by an extrusion process, a two-roll process, a calendaring process or a dry coating process. The thickness of the sheet may be from 0.01 to 1.0 mm. When the thickness of the sheet is less than 0.1 mm, physical properties of the sheet may be degraded and values as products may decrease since dispersion force may decrease on the surface. On the other hand, when the thickness of the sheet is greater than 1.0 mm, the material is not cross-linked and the manufacturing of a desired product cannot be performed.

The prepared sheet is cured by air drying. The curing by air drying used herein is drying at a high temperature using hot air or a heater. The drying may be performed at a temperature from 60 to 200⁰C , and preferably from 100 to 15O⁰C . When the temperature is lower than 6O⁰C , drying efficiency may decrease. On the other hand, when the temperature is higher than 200⁰C , mechanical properties of the product such as tear strength and elongation may be degraded although the drying is completed fast. In addition, the curing by air drying may be performed at a pressure from 1 to 10 atms. When the pressure is lower than 1 atm or higher than 10 atms, uniformity of the surface may decrease and cross-links may be cleaved. In operation (d), the bottom surface of the prepared nonflammable soft sheet is coated or impregnated with a flame-retardant adhesive to adhere the nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer, and the resultant product is cured by air drying to prepare a final nonflammable artificial leather.

Any adhesive that is incombustible may be used as the flame-retardant adhesive herein without limitation. The prepared nonflammable soft sheet is coated or impregnated with the flame-retardant adhesive to a predetermined thickness to adhere the nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer. The thickness of the flame-retardant adhesive may be from 0.01 to 0.4 mm. When the thickness of the flame-retardant adhesive is less than 0.01 mm, peeling strength may decrease due to low adhesive strength, and thus the layers may be separated. On the other hand, when the thickness of the flame-retardant adhesive is greater than 0.4 mm, drying takes too long time, and thus pot life properties may decrease. The nonflammable fiber layer is adhered to the nonflammable soft sheet through lamination while applying pressure thereto in a roll. The pressure of the roll may be from 1.0 to 10 kgf. When the pressure is too low, adhesive strength is not sufficient. On the other hand, when the pressure is too high, the nonflammable fiber or the nonflammable soft sheet may be destroyed. The sheet to which the nonflammable fiber is adhered is cured by air drying to prepare the final product. Here, the curing may be performed at a temperature from 60 to 200⁰C and preferably 80 to 180⁰C . When the temperature is lower than 6O⁰C , the curing takes too long time, thereby being cost-inefficient. On the other hand, when the temperature is higher than 200⁰C , mechanical properties of the product such as tear strength and elongation may be degraded.

The prepared product itself may be used, but a surface-treating process may further be included in order to obtain a natural leather-like touch, and reinforce mechanical properties such as abrasion resistance and scratch resistance.

In order to thicken the nonflammable artificial leather and improve comfort, a process of adhering a foam layer to the artificial leather may further be included. In the process, the fiber layer of the prepared nonflammable artificial leather is coated or impregnated with a flame-retardant adhesive to adhere an aluminum and silica foam to the fiber layer, and the resultant product is cured by air drying. The drying may be performed at a temperature from 60 to 200 °C, and preferably from 100 to 15O⁰C . When the temperature is lower than 6O⁰C , drying process takes too long time, thereby being cost-inefficient. On the other hand, when the temperature is higher than 200⁰C , mechanical properties of the product may be degraded.

Since only flame-retardant materials are used, the nonflammable artificial leather according to the present invention has excellent nonflammability or flame-retardancy and is environmentally friendly since harmful dioxine and black smoke are not emitted when burned.

The present invention also provides a method of preparing a nonflammable artificial leather having sound-absorbing properties. In the method of preparing a nonflammable artificial leather having sound-absorbing properties, a process of forming a foam sheet is added to the method of preparing the nonflammable artificial leather.

Specifically, the method of preparing a nonflammable artificial leather having sound-absorbing properties includes: (a) preparing a primary material by mixing polysiloxane, an inorganic hydroxide and an additive including a processing aid and processing the mixture; (b) preparing a final material by mixing the primary material, an inorganic filler, and a Pt compound and removing bubbles; (c) preparing a nonflammable soft sheet by processing the final material to form a sheet and curing the resultant product by air drying; (d) coating or impregnating the bottom surface of the nonflammable soft sheet with a flame-retardant adhesive to adhere a nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer, and curing the resultant product by air drying; and (f) forming silicon foam on the bottom surface of the nonflammable fiber layer, and curing the resultant product by air drying. The processing the final material may be performed by an extrusion process, a two-roll process, a calendaring process or a dry coating process in operation (c). The curing in operation (c) may be performed at a temperature from 60 to 200⁰C and at a pressure from 1 to 10 atms.

The method may further include (e) coating or impregnating the bottom surface of the nonflammable fiber layer with a nonflammable adhesive to adhere an aluminum and silica foam to the nonflammable fiber layer, and curing the resultant product by air drying after operation (d).

The present invention will now be described in greater detail with reference to the following examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Examples Example 1

60 % by weight of dimethylpolysiloxane having a viscosity of from 10,000 to 20,000 cps, 35% by weight of a mixture of magnesium hydroxide and aluminum hydroxide in a weight ratio of 45:55, and 3.4% by weight of silica as a strengthening agent, 1.5% by weight of dihydroxy polydimethyl polysiloxane which is a low-viscous silicon polymer as a processing aid, and 0.1 % by weight of magnesium salt as an inner releasing agent were mixed in an extruding and mixing apparatus for 2 hours. Then, based on 100 parts by weight of the mixture, 10 parts by weight of calcium carbonate, 15 parts by weight of anhydrous silicic acid and 0.014 parts by weight of Pt{P(CH₃)₃}₄ as a Pt compound were added to a rotary mixer and mixed for 1 hour, and bubbles were completely removed using a bubble removing apparatus under reduced pressure.

The prepared material was dispersed and plasticized using a two-roll mill to prepare a sheet having a thickness of 1.0 mm, and the resultant sheet was cured by air drying in a hot air oven at 17O⁰C at 1 atm. Then, a flame-retardant adhesive was uniformly dispersed using a roll and a carbon fiber paper as a nonflammable fiber paper was adhered to the cured sheet under 5 kgf, and the resultant product was cured by air drying at 100⁰C for 4 hours to prepare a nonflammable artificial leather.

Example 2

A nonflammable artificial leather was prepared in the same manner as in Example 1 , except that 20 parts by weight of anhydrous silicic acid and a basalt fiber paper as the nonflammable fiber paper were used.

Example 3

A nonflammable artificial leather was prepared in the same manner as in Example 1 , except that a flame-resistant cotton fiber paper as the nonflammable fiber paper were used. Example 4

A nonflammable artificial leather having improved cushioning properties was prepared by coating a flame-retardant adhesive on the bottom surface of the artificial leather sheet prepared in Example 1 to a thickness of from 0.1 to 0.4 mm, adhering an alumina/silica foam to the artificial leather sheet and curing the resultant product by air drying at 100⁰C for 8 hours.

Example 5

85 % by weight of dimethylpolysiloxane having a viscosity of from 10,000 to 20,000 cps, 10% by weight of a mixture of magnesium hydroxide and aluminum hydroxide in a weight ratio of 45:55, and 3.4% by weight of a silica filler as a strengthening agent, 1.5% by weight of dihydroxy polydimethyl polysiloxane which is a low-viscous silicon polymer as a processing aid, and 0.1 % by weight of magnesium salt as an inner releasing agent were mixed in an extruding and mixing apparatus for 2 hours. Then, based on 10O parts by weight of the mixture, 10 parts by weight of calcium carbonate, 15 parts by weight of anhydrous silicic acid and 0.014 parts by weight of Pt{P(CH₃)₃}₄ as a Pt compound were added to a rotary mixer, and mixed for 1 hour, and bubbles were completely removed using a bubble removing apparatus under reduced pressure.

The prepared material was dispersed and plasticized using a two-roll mill to prepare a sheet having a thickness of 1.0 mm, and the resultant sheet was cured by air drying in a hot air oven at 17O⁰C at 1 atm. Then, a flame-retardant adhesive was uniformly dispersed using a roll and a carbon fiber paper as a nonflammable fiber paper was adhered to the uncured sheet under 5 kgf, and the resultant product was cured by air drying at 100⁰C for 4 hours to prepare a nonflammable artificial leather. Example 6

The artificial leather sheet prepared in Example 1 was punched by continuously passing the artificial leather through a single-shot punching mold having punching holes with a predetermined pattern. Then, a foam sheet was prepared by placing a commercially available silicon foam grade in a mold, and the foam sheet was covered with the artificial leather to prepare a nonflammable artificial leather for a cushion and a sound-absorbing material.

Comparative Example 1 A conventional flame-retardant artificial leather UB010605150002 manufactured by LG Chem, LTD. was tested. Performance Evaluation

The nonflammable artificial leather prepared in Examples 1 to 4 and the commercially available flame-retardant artificial leather prepared in Comparative Example 1 were tested.

Incombustibility Evaluation

Surface tests and additional tests were carried out by testing incombustibility of interior materials and construction of buildings according to KS F 2271-2003, and incombustibility was tested by testing noxious gas. Surface test and additional test

Samples were put in a furnace and heated for 10 minutes (3 minutes using propane and 7 minutes using electric heating wire) for testing flame retardancy grades I and II, and for 6 minutes (3 minutes using propane and 3 minutes using electric heating wire) for testing flame retardancy grade III. The results are shown in Table 1

Table 1

Noxious gas test

8 white rats (ICR, female, 5 weeks after birth, weight: 15 to 22 g) were placed in a rotary basket. Then, samples were put in a furnace and heated for 6 minutes (3 minutes using propane and 3 minutes using electric heating wire). The gas emitted from combusted samples were transmitted through a stirring case to the rotary basket, and effects of combustion gas on the white rats were observed. Actions of the white rats exposed to the gas were continuously measured for 15 minutes after the heating was initiated until the white rats stop action (action stopping time). An average action stopping time longer than 9 minutes is determined as pass.

Far infrared ray emission test

A far infrared ray emission test was evaluated according to regulations of KFIA-F1-1005.

The test was performed at 37⁰C by comparing with black body using FT-IR spectrometer. The results are shown in FIG. 6.

Tear strength test

Samples were cut into 40 mm (width) X 150 mm (length) pieces, and the pieces were vertically fixed to clips of a tensile testing device. The tensile testing device was operated at 200 +2m/min. The weight and extended length of the samples were measured. If the samples slide out of clips of the tensile testing device or tears occur but not in the central region, they are re-tested. The tear strength is a maximum load when the samples tear.

The results are shown in Table 2.

Table 2

As can be seen from Table 1 , the nonflammable artificial leathers prepared in Examples 1 through 4 passed the surface test and additional test, and showed longer than 12 minutes in the noxious gas test, and thus the nonflammable artificial leathers have excellent incombustibility. In addition, the tear strength of the nonflammable artificial leathers prepared in Examples 1 through 4 was similar to that of conventional nonflammable artificial leathers. The nonflammable artificial leathers have excellent far infrared ray emission properties, and as such are beneficial to humans and good for balancing biorhythm.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

1. A nonflammable artificial leather comprising: a nonflammable soft sheet material layer including polysiloxane, an inorganic hydroxide, a Pt compound and an inorganic filler; and a nonflammable fiber layer.

2. The nonflammable artificial leather of claim 1 , wherein viscosity of the polysiloxane is from 1 ,000 to 500,000 cps.

3. The nonflammable artificial leather of claim 1 , wherein the inorganic hydroxide is selected from the group consisting of aluminum hydroxide, magnesium hydroxide, and combinations thereof.

4. The nonflammable artificial leather of claim 1 , wherein the inorganic filler is selected from the group consisting of SiO₂, AI₂O₃, Fe₂O, CaO, MgO, K₂O, Na₂O and combinations thereof.

5. The nonflammable artificial leather of claim 1 , wherein the nonflammable soft sheet material layer comprises 2 to 97% by weight of polysiloxane, 1 to 50% by weight of the inorganic hydroxide and 0.01 to 0.5% by weight of the Pt compound.

6. The nonflammable artificial leather of claim 1 , wherein the amount of the inorganic filler is from 1 to 30% by weight based on the total amount of the nonflammable soft sheet material layer.

7. The nonflammable artificial leather of claim 1 , wherein the nonflammable fiber layer comprises one selected from the group consisting of a carbon fiber, a basalt fiber, a flame-resistant cotton fiber, an alumina fiber, a silica fiber and combinations thereof.

8. The nonflammable artificial leather of any one of claims 1 through 7, further comprising a polyurethane coating layer on the nonflammable soft sheet material layer.

9. The nonflammable artificial leather of any one of claims 1 through 7, further comprising a foam layer formed of an alumina fiber or a silica fiber on the bottom surface of the nonflammable fiber layer.

10. The nonflammable artificial leather of claim 8, further comprising a foam layer formed of an alumina fiber or a silica fiber on the bottom surface of the nonflammable fiber layer.

11. A nonflammable artificial leather having sound-absorbing properties comprising: a nonflammable artificial leather according to any one of claims 1 through 10; and a silicon foam sheet adhered to one surface of the nonflammable artificial leather.

12. A method of preparing a nonflammable artificial leather, the method comprising:

(c) preparing a nonflammable soft sheet by processing the final material to form a sheet and curing the resultant product by air drying; and

(d) coating or impregnating the bottom surface of the nonflammable soft sheet with a flame-retardant adhesive to adhere a nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer, and curing the resultant product by air drying.

13. The method of claim 12, wherein the processing of the final material in operation (c) is performed by an extrusion process, a two-roll process, a calendaring process or a dry coating process.

14. The method of claim 12, wherein the curing in operation (c) is performed at a temperature from 60 to 200⁰C and at a pressure from 1 to 10 atms.

15. The method of any one of claims 12 through 14, further comprising (e) coating or impregnating the bottom surface of the nonflammable fiber layer with a nonflammable adhesive to adhere an aluminum and silica foam to the nonflammable fiber layer, and curing the resultant product by air drying after operation (d).

16. A method of preparing a nonflammable artificial leather having sound-absorbing properties, the method comprising:

(c) preparing a nonflammable soft sheet by processing the final material to form a sheet and curing the resultant product by air drying; (d) coating or impregnating the bottom surface of the nonflammable soft sheet with a flame-retardant adhesive to adhere a nonflammable fiber to the nonflammable soft sheet to form a nonflammable fiber layer, and curing the resultant product by air drying; and.

17. The method of claim 16, wherein the processing of the final material in operation (c) is performed by an extrusion process, a two-roll process, a calendaring process or a dry coating process.

18. The method of claim 16, wherein the curing in operation (c) is performed at a temperature from 60 to 200⁰C and at a pressure from 1 to 10 atms.

19. The method of any one of claims 16 through 18, further comprising (e) coating or impregnating the bottom surface of the nonflammable fiber layer with a nonflammable adhesive to adhere an aluminum and silica foam to the nonflammable fiber layer, and curing the resultant product by air drying after operation (d).