JPH0742084A - Leather-like sheet-shaped material - Google Patents

Abstract

PURPOSE:To obtain a leather-like sheet-shaped material which can be prevented from various kinds of ill effects caused by heat accumulation. CONSTITUTION:This is related to a leather-like sheet-shaped material having a colored urethane layer as the essential constituting layer. In this leather-like sheet-shaped material, the colored polyurethane layer is colored without using a carbonaceous pigment by using a pigment having <=50% ratio of infrared ray absorption defined in the specification.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like sheet material that suppresses temperature rise, and more particularly to a leather-like sheet material that suppresses heat generation due to heat storage as much as possible and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, a lot of so-called suspected leather products such as PVC leather, synthetic leather, artificial leather, etc., which are similar to leather, have been provided on the market, but their attractive appearance, texture and excellent performance Etc. have been recognized and their applications are expanding.

Conventionally, pigments have been used as colorants in coloring these products in medium to dark colors, and a target hue has been obtained by combining and combining a chromatic color pigment and a black pigment.

In particular, a carbon black pigment containing carbon as a main component (hereinafter referred to as CB) is used as a black pigment. When the surface of synthetic leather containing such a pigment is exposed to the rays of the sun, it emits ultraviolet rays. Absorbs light in the visible and infrared regions. As a result of spectroscopic measurement using a polyurethane film containing a thickness of 20 μm and a solid content of CB pigment of 15% by weight, a reflectance of 4%, a transmittance of 0% and an absorptivity of 96% in a wavelength range of 400 to 2000 nm. It is clear from that On the other hand, the energy distribution with respect to the wavelength of the sun's rays has a peak around 500 nm,
Since it is in the range of nm, it is understood that CB in the film is a high absorber of visible / infrared light.

This absorbed infrared light is converted into thermal energy, and the mechanism is that the natural frequency of each vibration between constituent atoms in many substance molecules is generally within the infrared frequency range. For this reason, when infrared rays hit these substances, infrared rays that match the natural frequency of the substance molecule are picked up from it, which is, so to speak, resonantly absorbed, and the vibration of the molecule is excited. As a result, the amplitude becomes large and the phenomenon of heat generation is exhibited.

When the molecule returns from the excited state to the original state, it is released as heat.

Generally, synthetic leather or the like has a low thermal conductivity, so that heat once generated by absorption of infrared rays of sunlight is accumulated in the leather.

Such materials are used as interior materials for vehicles, for example, door trims, handle covers, instrument panels, and other skin materials, and particularly when such vehicles are exposed outdoors to sunlight, they are bare hands. Not only the temperature of the interior material rises to such an extent that it is impossible to contact them, but also the temperature of the interior space of the vehicle rises, which gives an occupant a discomfort. This is also a major factor in deteriorating the cooling efficiency of the cooling cooler installed in the vehicle and accelerating the rise in energy costs.

Further, there is a problem in that the increase in the temperature inside the vehicle adversely affects various devices installed in the instrument panel inside the vehicle.

When the above-mentioned skin material is considered in detail, such a material is mainly composed of a combination of a cloth-like base material composed of polyester fibers and a polyurethane resin, and therefore, in use. Deterioration due to the heat accumulated inside is obvious, and in addition, heat generation by CB contained as a colorant accelerates the thermal deterioration of each constituent of the leather and has a bad influence on various physical properties and performance. Become.

[0011]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a leather-like sheet material which effectively prevents the above-mentioned various harmful effects due to heat storage. The inventors of the present invention have earnestly studied the mechanism and the prevention method of the deterioration action of the leather-like sheet structure due to heat storage, and as a result, the present invention having remarkable effects has been reached.

[0012]

The present invention provides a leather-like sheet having a colored polyurethane layer as an essential constituent layer, wherein the colored polyurethane layer uses a pigment having an infrared absorption rate of 50% or less as specified in the specification, and a carbon It is a leather-like sheet-like product that is colored without using a quality pigment.

Essentially any leather-like sheet material having a urethane layer can be used as the leather-like sheet material in the present invention, but it is not colored or dyed with a woven or knitted fabric, a non-woven fabric or the like. A colored polyurethane film is laminated with an adhesive on the fibrous base material, and the napped fibrous base material such as smooth synthetic leather, woven or knitted fabric that is not colored or dyed with a dye is impregnated with colored polyurethane. After the wet coagulation treatment, the colored polyurethane film is laminated with an adhesive, the smooth synthetic leather and the fiber base material are impregnated with the colored polyurethane, the wet coagulation treatment is performed, and the surface is ground to give the colored suede synthetic leather and napped hair. A colored suede-like synthetic leather is preferably used by impregnating a fibrous base material with colored polyurethane, subjecting it to wet coagulation treatment, and then subjecting it to fluff exposure treatment. The main components of these leather-like sheet materials (synthetic leather) are as shown in FIGS.

A feature of the present invention is that a carbonaceous pigment represented by carbon black is not used as a main coloring material or a hue correcting coloring material in coloring the colored polyurethane layer in the leather-like sheet material as described above. The point is to use a pigment having an infrared absorption rate of 50% or less defined in 1.

That is, polyurethane resin (typical example CRISV
ON NY333 (Dainippon Ink) solid content 2
A pigment was added to a 5% by weight dimethylformamide solution so that the pigment solid content ratio was 15% by weight based on the resin solid content to form a film with a thickness of 20 μm, and the reflectance and transmittance were measured with a visible / infrared spectrophotometer. When the absorptance of the colored film is calculated from the data obtained by measuring the rate, the average absorptance in the wavelength range of 900 to 1500 nm is the infrared absorptivity in the present invention.

The average absorptivity mentioned above is measured from the spectrum of reflectance and transmittance of the film produced according to the above with a visible / infrared spectrometer (for example, Hitachi U-4000).
The average reflectance and the average transmittance are obtained over the wavelength region of 1500 nm, and the average absorptance in this wavelength region is calculated based on the following formula. Average absorption rate (%) = {100- (average reflectance + average transmittance)} (%)

The pigments preferably used in the present invention include organic pigments such as quinone type, perylene type, azomethine azo type and inorganic pigments such as titanium oxide and red iron oxide, and especially black pigments satisfying the above. preferable.

These pigments may be used alone, but it is also possible to use them as a main color material or a color material for hue correction and to use other color materials in combination therewith. Also in this case, it is necessary to satisfy the above-mentioned regulation of the infrared absorption rate as a whole.

Next, examples and comparative examples will be shown.

Example 1 Polyester ultrafine fibers (single yarn about 0.5
d), a 3-bar tricot cloth using a polyester fiber of 75d / 25f for the middle yarn and the back yarn was dyed and raised to obtain a base fabric having a basis weight of about 320 g / m ² .

On the raised surface of this base cloth, a coating resin dispersion having the following formulation was applied to a thickness of 6 with a knife over roll coater.
It was evenly applied at 80 g / m ² and immersed in a 20 ° C. water bath for 5 minutes to solidify.

Then, it was washed with warm water at 60 ° C. for 1 hour, drained with mangle and dried at 100 ° C. for 20 minutes to obtain a microporous sheet material.

Next, the surface of the film of the microporous sheet material is pressed against a rotating drum around which abrasive paper with a grain size of 120 is wound, and 0.1 mm is ground from the film surface and napped to give a suede-like synthetic leather. Obtained (Fig. 4).

[0024]

[Table 1]

Comparative Example 1 In the same manner as in Example 1, a dyed raised cloth was used, and only the composition of the coating resin dispersion was changed as follows, and coating, wet coagulation, and surface grinding were performed to obtain suede cloth. Toned synthetic leather was obtained.

[0026]

[Table 2]

The two kinds of synthetic leathers obtained in Example 1 and Comparative Example 1 were irradiated with light in an accelerated xenon light resistance tester (“WT-341” manufactured by Wacom Co.) in an atmosphere of 89 ° C., and the back surface of the sample was measured. The temperature rise was detected by a thermo label, and the history of maximum exothermic temperature during irradiation was examined and compared. The results are shown in the table below.

[0028]

[Table 3]

Example 2 Polyester fine fibers (about 0.5 single yarn) were used as front yarns.
d), a 3-bar tricot cloth using a polyester fiber of 75d / 25f for the middle yarn and the back yarn was dyed and raised to obtain a base fabric having a basis weight of about 320 g / m ² .

On the raised surface of this base cloth, a coating resin dispersion of the following formulation A was used with a knife over roll coater 73
It was evenly applied at 0 g / m ² and immersed in a 20 ° C. water bath for 5 minutes to solidify.

Next, it was washed with warm water at 60 ° C. for 1 hour, drained with mangle and dried at 100 ° C. for 20 minutes to obtain a microporous sheet material.

[0032]

[Table 4]

On the other hand, a PU coating solution for the skin layer having the following formulation a was coated on a release paper with a knife coater in an amount so as to give a dry thickness of 20 μm, and dried by heating at 100 ° C. for 3 minutes. A film for use was formed.

Further, an adhesive prepared by the following adhesive formulation was coated on this film in an amount so as to give a basis weight of 120 g / m ² , and the above microporous film was immediately laminated thereon, Then, it was pressure bonded by a laminating roll.

The resulting laminate was dried at 100 ° C. for 2 minutes, cured at 50 ° C. for 3 days, and then released and peeled to obtain a smooth synthetic leather (FIG. 2).

[0036]

[Table 5]

Comparative Example 2 As in Example 1, a dyed raised fabric was used, the composition of the coating resin dispersion was changed as in Formulation B, coating was performed, and wet coagulation was performed to obtain a microporous sheet material. It was

[0038]

[Table 6]

Further, the film prepared according to the prescription a was laminated on the microporous sheet material in the same manner as in Example 2 to obtain a smooth synthetic leather.

Comparative Example 3 Using the same raised cloth as in Example 2, the composition of the coating resin dispersion liquid was changed as in the case of the above prescription A, coating was performed, and wet coagulation was performed to obtain a microporous sheet material. .

Further, a film prepared according to the following formulation b was laminated on this microporous sheet material in the same manner as in Example 2 to obtain a smooth synthetic leather.

[0042]

[Table 7]

Comparative Example 4 Using the same raised fabric as in Example 2, the composition of the coating resin dispersion liquid was changed as in the case of the above-mentioned formulation B, coating was performed, and wet coagulation was performed to obtain a microporous sheet material. .

Further, the film prepared according to the above prescription b was laminated on this microporous sheet material in the same manner as in Example 2 to obtain a smooth synthetic leather.

COMPARATIVE EXAMPLE 5 A polyester superfine fiber spun-dyed yarn (single yarn 0.
5d), 3 bar tricot cloth using 75d / 25f polyester fiber for the middle yarn and the back yarn was dyed and raised to obtain a base fabric having a basis weight of about 320 g.

The base resin was coated with the coating resin dispersion of the above formulation A and wet-coagulated to obtain a microporous sheet material.

Further, the film prepared according to the above prescription a was laminated on the microporous sheet material in the same manner as in Example 2 to obtain a smooth synthetic leather.

In order to compare the difference in temperature rise due to the colorant of each constituent, the five kinds of synthetic leathers obtained in Example 2 and Comparative Examples 2, 3, 4, 5 were subjected to an accelerated xenon light resistance tester. (“WT-341” manufactured by Wacom Co., Ltd.), light irradiation was performed for 1 hour in an atmosphere of 89 ° C., a temperature increase on the back surface of the sample was detected by a thermo label, and the maximum exothermic temperature history during irradiation was examined and compared.

[0049]

[Table 8]

[0050]

The leather-like sheet material of the present invention does not use a carbonaceous pigment, which is a high absorber of visible / near infrared rays, in each constituent layer, and absorbs light in the visible region as seen in the above examples. However, it produces a black color and effectively reflects and transmits wavelengths in the near-infrared region, and thus generates very little heat. As a result, it is an epoch-making leather-like sheet material capable of suppressing discomfort caused by heat generation and suppressing deterioration of the leather itself due to heat.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a leather-like sheet material of the present invention.

FIG. 2 is a sectional view showing an example of a leather-like sheet material of the present invention.

FIG. 3 is a sectional view showing an example of a leather-like sheet material of the present invention.

FIG. 4 is a sectional view showing an example of a leather-like sheet material of the present invention.

[Explanation of symbols]

 1 Skin Layer 2 Adhesive Layer 3 Wet Polyurethane Sponge Layer 4 Fiber Substrate 5 Standing Fiber

Claims (5)

[Claims] 1. A leather-like sheet material having a colored polyurethane layer as an essential constituent layer, wherein the colored polyurethane layer is colored with a pigment having an infrared absorption rate of 50% or less as specified in the specification and without using a carbonaceous pigment. A leather-like sheet characterized by being characterized. 2. The leather according to claim 1, wherein the leather-like sheet material is a smooth synthetic leather obtained by laminating a colored polyurethane film on an uncolored or dye-dyed fiber substrate with an adhesive. Like sheet. 3. A smooth tone obtained by impregnating a colored polyurethane film into a fibrous substrate which is not colored or dyed with a dye, is wet-coagulated, and is laminated with an adhesive to form a colored polyurethane film. The leather-like sheet material according to claim 1, which is a synthetic leather. 4. A suede-like synthetic leather obtained by impregnating a colored polyurethane into a fibrous base material in which the leather-like sheet material is not colored or is dyed with a dye, wet coagulation treatment, and then surface grinding. The leather-like sheet material according to 1. 5. A suede-like synthetic leather obtained by impregnating a napped fiber base material in which a leather-like sheet material is not colored or colored with a dye with colored polyurethane, wet-coagulated and then exposed to fluff. Item 2. A leather-like sheet material according to item 1.