JP3180238B2 - Leather-like sheet - Google Patents

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 which suppresses temperature rise, and more particularly to a leather-like sheet which minimizes heat generation due to heat storage and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, so-called suspicious leather products such as PVC leather, synthetic leather, artificial leather, etc., which are similar to leather, have been provided to the market in large quantities, but their attractive appearance, texture, and excellent performance have been provided. Etc., and its use is expanding.

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

[0004] In particular, carbon black pigments (hereinafter referred to as CB) containing carbon as a main component are used as black pigments. However, when the surface of synthetic leather containing such pigments is irradiated with the sun's rays, ultraviolet and ultraviolet rays are emitted. Absorbs visible and infrared light. This means that the reflectance was 4%, the transmittance was 0%, and the absorption was 96% in the wavelength region of 400 to 2,000 nm, as a result of spectroscopic measurement on a polyurethane film containing 20 μm in thickness and 15% by weight of CB pigment solids. Is evident from the fact that On the other hand, the energy distribution with respect to the wavelength of the solar ray has a peak near 500 nm, and is 300 to 2,000.
Since it is in the range of nm, it can be understood that CB in the film is a high absorber of visible / infrared light.

[0005] The absorbed infrared light is converted into thermal energy. The mechanism is that the natural frequency of each vibration between constituent atoms in many substance molecules is generally within the frequency range of infrared light. For this reason, when infrared rays hit these substances, infrared rays that match the natural frequency of the substance molecules are picked up from them and they are resonantly absorbed, so that the vibrations of the molecules are excited. As a result, the amplitude increases 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.

In general, synthetic leather and the like have a low thermal conductivity, so that heat once generated by the absorption of infrared rays of sunlight is accumulated in the leather.

Such a material is used as an interior material for a vehicle, for example, as a skin material for a door trim, a handle cover, an instrument panel, or the like. In particular, in a vehicle where such a vehicle is exposed to sunlight outdoors, a bare hand is used. Not only does the temperature of the interior material rise to such an extent that contact is impossible, but also the temperature of the interior space of the vehicle rises, giving the passenger discomfort. This is also a major factor in deteriorating the cooling efficiency of the cooling cooler installed in the vehicle and accelerating the increase in energy costs.

Further, there is a problem that this rise in the temperature inside the vehicle adversely affects various devices mounted in the instrument panel inside the vehicle.

When the above-mentioned skin material is considered in detail, since such a material is mainly composed of a combination of a cloth-like base material made of polyester fiber and mainly a polyurethane resin, it is difficult to use the material during use. Deterioration caused by heat accumulated inside is obvious, and in addition, heat generated by CB contained as a coloring agent accelerates thermal deterioration of each constituent of the leather and significantly affects various physical properties and performances. Become.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a leather-like sheet which effectively prevents various adverse effects caused by heat storage as described above. The present inventors have conducted intensive studies on the mechanism and prevention method of the deterioration effect due to heat storage of the leather-like sheet-like structure, and as a result, the present invention has achieved a remarkable effect.

[0012]

According to the present invention, there is provided a leather-like sheet having a colored polyurethane layer as an essential constituent layer, wherein the colored polyurethane layer comprises a pigment having an infrared absorption of 50% or less as specified in the specification and carbon black. It is a leather-like sheet that is colored without using a quality pigment.

As the leather-like sheet in the present invention, essentially any leather-like sheet having a urethane layer can be used, but it is not colored, or is woven or knitted, non-woven fabric, etc. The colored polyurethane film is laminated with an adhesive on the fiber base material, and the colored polyurethane is impregnated into the raised fiber base material such as smooth synthetic leather, non-colored or dyed woven or knitted fabric or nonwoven fabric. After the wet coagulation treatment, the colored polyurethane film is laminated with an adhesive, and the colored polyurethane is impregnated into the smooth synthetic leather and the fiber base material. After the wet coagulation treatment, the surface is ground. A colored suede-like synthetic leather is preferably used by impregnating a colored base material with a colored polyurethane, performing a wet coagulation treatment, and then performing a fluff exposure treatment. The main structure of these leather-like sheets (synthetic leather) is as shown in FIGS.

The present invention is characterized in that a carbonaceous pigment represented by carbon black is not used as a main color material or a hue correction color material in coloring the colored polyurethane layer in the leather-like sheet material as described above. The use of a pigment having an infrared absorptivity of 50% or less as defined in (1).

Namely, a polyurethane resin (typically CRISV)
ON NY333 (Dai Nippon Ink))
A pigment is blended with a 5% by weight dimethylformamide solution so that the pigment solids content becomes 15% by weight based on the resin solid content to form a film having a thickness of 20 μm, and the reflectance and transmittance are measured by a visible / infrared spectrophotometer. When the absorption is measured and the absorption of the colored film is calculated from the data, the average absorption in the wavelength range of 900 to 1500 nm is the infrared absorption in the present invention.

The above-mentioned average absorptance can be determined by measuring the reflectance and transmittance spectra of the film produced as described above using a visible / infrared spectrometer (for example, Hitachi U-4000), and determining the 900 nm
The average reflectance and average transmittance are determined over the wavelength region of 1500 nm, and the average absorptance in this wavelength region is calculated based on the following equation. Average absorption (%) = {100- (average reflectance + average transmittance)} (%)

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

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

Next, examples and comparative examples will be described.

Example 1 Polyester ultrafine fiber (about 0.5 single yarn) was used as the front yarn.
d) A 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 with a basis weight of about 320 g / m ² .

A coating resin dispersion having the following formulation was applied to the raised surface of the base fabric with a knife over roll coater to a thickness of 6 μm.
80 g / m ² was uniformly applied and immersed in a 20 ° C. water bath for 5 minutes to solidify.

Next, the plate was washed with warm water at 60 ° C. for 1 hour, drained with a 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 wrapped with abrasive paper having a grain size of 120, and 0.1 mm is ground and napped from the film surface to produce suede-like synthetic leather. (FIG. 4).

[0024]

[Table 1]

Comparative Example 1 In the same manner as in Example 1, using a dyed brushed cloth, only the composition of the coating resin dispersion was changed as follows, and coating, wet solidification, and surface grinding were performed. Synthetic leather was obtained.

[0026]

[Table 2]

The two types 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) at an atmosphere of 89 ° C. The temperature rise was detected by a thermo label, and the maximum exothermic temperature history during irradiation was examined and compared. The results are shown in the following table.

[0028]

[Table 3]

Example 2 Polyester ultrafine fiber (about 0.5 single yarn) was used as the front yarn.
d) A 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 with a basis weight of about 320 g / m ² .

On the raised surface of the base fabric, a coating resin dispersion of the following formula A was applied with a knife over roll coater for 73 hours.
The solution was uniformly coated at 0 g / m ² and immersed in a 20 ° C. water bath for 5 minutes to solidify.

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

[0032]

[Table 4]

On the other hand, a PU solution for a skin layer having the following formulation a was applied on release paper using a knife coater in an amount so as to have a dry thickness of 20 μm, and dried by heating at 100 ° C. for 3 minutes. Film was formed.

Further, an adhesive prepared by the following adhesive formulation was applied on this film in an amount such that a basis weight of 120 g / m ² was obtained. Immediately thereafter, the above microporous film was laminated thereon. Subsequently, it was press-bonded by a laminate roll.

The obtained 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 In the same manner as in Example 1, using a dyed napping cloth, the composition of the coating resin dispersion was changed as in Formulation B, and the composition was coated and wet-solidified to obtain a microporous sheet material. Was.

[0038]

[Table 6]

Further, a film prepared according to Formulation 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 brushed cloth as in Example 2, the composition of the coating resin dispersion was changed as in Formula A above, and the coating was applied and wet solidified to obtain a microporous sheet material. .

Further, a film prepared according to the following formulation b was laminated on the 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 brushed cloth as in Example 2, the composition of the coating resin dispersion was changed as in the above Formulation B, and the composition was coated and wet-solidified to obtain a microporous sheet material. .

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

Comparative Example 5 The original yarn of polyester extra fine fiber (single yarn 0.1.
5d) A 3-bar tricot cloth using 75d / 25f polyester fiber as a middle yarn and a back yarn was dyed and raised to obtain a base fabric with a basis weight of about 320 g.

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

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

To compare the difference in temperature rise due to the coloring agent of each constituent, the five types of synthetic leathers obtained in Example 2 and Comparative Examples 2, 3, 4, and 5 were subjected to an accelerated xenon light resistance tester. The sample was irradiated with light for 1 hour in an atmosphere of 89 ° C. (“WT-341” manufactured by Wacom), the temperature rise on the back surface of the sample was detected by a thermo label, and the maximum heat generation temperature during irradiation was examined and compared.

[0049]

[Table 8]

[0050]

The leather-like sheet of the present invention does not use a carbonaceous pigment which is a high absorber of visible / near-infrared light in each constituent layer, and absorbs light in the visible region as seen in the above examples. In addition, the black color is developed, and the heat generation is very small because the wavelength in the near infrared region is effectively reflected and transmitted. 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 the drawings]

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Skin layer 2 Adhesive layer 3 Wet polyurethane sponge layer 4 Fiber base material 5 Napped fiber

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D06N 3/14 B32B 27/12 B32B 27/20 B32B 27/40 B32B 33/00

Claims (5)

(57) [Claims] 1. A leather-like sheet having a colored polyurethane layer as an essential constituent layer, wherein the colored polyurethane layer is colored using a pigment having an infrared absorption of 50% or less as specified in the specification and without using a carbonaceous pigment. A leather-like sheet material characterized by being made. 2. The leather according to claim 1, wherein the leather-like sheet is a smooth synthetic leather obtained by laminating a colored polyurethane film with an adhesive on a non-colored or dyed fiber base material. Like sheet. 3. A smooth tone obtained by impregnating a colored polyurethane with a fiber base material in which a leather-like sheet is not colored or colored with a dye, wet-coagulating, and laminating a colored polyurethane film with an adhesive. The leather-like sheet according to claim 1, which is a synthetic leather. 4. A suede-like synthetic leather obtained by impregnating a colored polyurethane with a fibrous base material whose leather-like sheet is not colored or colored with a dye, wet coagulation treatment, and surface grinding. 2. The leather-like sheet according to 1. 5. A suede-like synthetic leather which is obtained by impregnating a nap fiber base material whose leather-like sheet is not colored or colored with a dye by a colored polyurethane, wet coagulating treatment, and exposing fluff. Item 2. A leather-like sheet according to Item 1.