WO2015001732A1

WO2015001732A1 - Synthetic leather for automobile

Info

Publication number: WO2015001732A1
Application number: PCT/JP2014/003197
Authority: WO
Inventors: 金子　幸人; 朗斉田; 知行上村
Original assignee: セーレン株式会社; 本田技研工業株式会社
Priority date: 2013-07-05
Filing date: 2014-06-16
Publication date: 2015-01-08
Also published as: JPWO2015001732A1; CN105377626B; JP6353833B2; BR112015032666A2; MX2015016993A; CN105377626A; MX368105B

Abstract

The present invention provides an exceptionally durable synthetic leather for an automobile that has excellent visual quality when used in a vehicle seat, and that is suitable for application in an automobile interior. A synthetic leather comprising a fibrous substrate (2), a surface layer (3) made of a polyurethane resin, and a protective layer (4) made of a polyurethane resin layered in the stated order, the fibrous substrate (2) being circular knitted fabric having a weight of 250 to 350 g/m², the protective layer (4) having a grained pattern in the surface, the thickness (T1) of the protective layer in peaks (5) of the grained pattern being 10 to 20 μm, the thickness (T2) of the protective layer in troughs (6) of the grained pattern being 3 to 10 μm, the BLC value of the synthetic leather being 3.8 to 5.5, and the 10% modulus value of the synthetic leather being 5 to 20 N/cm.

Description

Synthetic leather for automobiles

The present invention relates to a synthetic leather for automobiles. More specifically, the present invention relates to a synthetic leather that has good luster when used in a vehicle seat and has excellent durability suitable for automobile interior use, in particular, excellent wear resistance and flex resistance.

Generally, synthetic leather used as an automobile interior material is composed of a resin layer and a fibrous base material. As the fibrous base material, a nonwoven fabric and a woven fabric are preferably used because of excellent processability and dimensional stability. However, nonwoven fabrics and woven fabrics are inferior in stretchability while being excellent in dimensional stability. Therefore, when it is used for a product having a complicated three-dimensional shape, there is a problem that followability to the shape is poor, wrinkles are generated when the product is stuck, and the finish is inferior.

In order to solve the above problems, synthetic leather using a weft knitted fabric is disclosed as a fibrous base material.

For example, in Patent Document 1, a weft knitted fabric having a double-sided knitted structure is used as a fiber base material, and the surface of the fiber base material is made of a silicone-modified non-yellowing polycarbonate polyurethane resin via a polyurethane resin adhesive layer. A synthetic leather formed by laminating a polyurethane resin skin layer is disclosed. In Patent Document 1, it is described that, in addition to various properties such as light resistance, hydrolysis resistance, heat deterioration resistance, wear resistance, and oleic acid resistance, this is excellent in molding processability and formability. In Patent Document 2, in a synthetic leather in which a urethane-based adhesive layer and a polyurethane skin layer are sequentially laminated on a surface of a base fabric, the base fabric is a knitted fabric having a raised surface, and the length of the raised fiber is 20 to 99. Synthetic leather is disclosed in which% is present in the adhesive layer. The knitted fabric is a knitted fabric in which a spun yarn is passed as a weft yarn in the course direction and subjected to special knitting, and the longitudinal and lateral elongation rates of the base fabric are 60 to 100%. In Patent Document 2, it is described that it is difficult to fray and excellent in durability, tear strength, texture, and workability along the design. Patent Document 3 discloses a synthetic leather in which a polyurethane adhesive layer and a polyurethane skin layer are sequentially laminated on the raised surface side of a raised circular knitted fabric. As the raised circular knitted fabric, the ground yarn and the raised yarn are made of a polyester multifilament yarn, and the ratio of the supplied yarn length of the ground yarn to the raised yarn is 1: 1.1 to 1: 1.3, the ratio of the number of stitches In which is 1: 1. In Patent Document 3, it is described that this is excellent in stretchability, texture, peel strength, and tear strength.

However, when the weft knitted fabric is used as the fibrous base material as in Patent Documents 1 to 3, the stretchability is improved as compared with the nonwoven fabric or the woven or knitted fabric, but the durability sufficient for automobile use, in particular, the abrasion resistance It is difficult to obtain flexibility and bending resistance.

Japanese Patent No. 3071383 Japanese Patent No. 3454433 Japanese Patent No. 3778750

An object of the present invention is to provide a synthetic leather that has good tension when used in a vehicle seat and is excellent in durability, particularly wear resistance and flex resistance, suitable for automobile interior use. .

A synthetic leather for automobiles according to an embodiment of the present invention is a synthetic leather in which a fibrous base material, a skin layer made of polyurethane resin, and a protective layer made of polyurethane resin are sequentially laminated, and the fibrous base material Is a circular knitted fabric with a basis weight of 250 to 350 g / m ² , the protective layer has a wrinkle pattern on the surface, and the thickness of the protective layer at the crest of the wrinkle pattern is 10 to 20 μm. The thickness of the protective layer in the part is 3 to 10 μm and smaller than the thickness in the peak part, the BLC value of the synthetic leather is 3.8 to 5.5, and the 10% modulus value of the synthetic leather is 5 to 20 N / cm.

According to the synthetic leather according to an embodiment, the mass of the polyurethane resin layer including the outer skin layer and the protective layer may be 0.4 to 0.8 times the mass of the fibrous base material. . In another embodiment, the constant load elongation of the fibrous base material may be 20 to 40% in the vertical direction and 30 to 50% in the horizontal direction.

When the synthetic leather according to the present embodiment is used for a vehicle seat, the finish is good, and the durability suitable for automobile interior use, in particular, the abrasion resistance and the bending resistance is excellent.

It is a schematic sectional drawing of the synthetic leather which concerns on embodiment. It is explanatory drawing about the evaluation method of sheet stickiness.

The synthetic leather which concerns on embodiment is synthetic leather by which a polyurethane protective layer is laminated | stacked through the polyurethane skin layer on the surface of a fibrous base material. That is, the synthetic leather includes a fibrous base material, a skin layer made of polyurethane resin formed on the fibrous base material, and a protective layer made of polyurethane resin formed on the skin layer. The fibrous base material is a circular knitted fabric having a basis weight of 250 to 350 g / m ² . The thickness of the embossed portion of the polyurethane protective layer is 10 to 20 μm, and the thickness of the embossed portion of the embossed pattern is 3 to 10 μm. The BLC value of synthetic leather is 3.8 to 5.5, and the 10% modulus value of synthetic leather is 5 to 20 N / cm.

When the BLC value of synthetic leather is 3.8 to 5.5 and the 10% modulus value of synthetic leather is 5 to 20 N / cm, the balance between softness and elongation is good and the synthetic leather is supple. Therefore, when used for a vehicle seat, no wrinkles are generated even in a complicated three-dimensional shape portion, and a synthetic leather having a good finish can be obtained.

If the BLC value is less than 3.8, the synthetic leather becomes coarse and hard when used for a vehicle seat. If the BLC value exceeds 5.5, the synthetic leather becomes too soft, and biting wrinkles occur during sewing, making it impossible to obtain the required wear resistance for the vehicle seat. The BLC value is more preferably 4.2 to 5.0.

If the 10% modulus value is less than 5 N / cm, the synthetic leather tends to be stretched, and the wear resistance required for the vehicle seat cannot be obtained. If the 10% modulus value exceeds 20 N / cm, the synthetic leather will not stretch well, and the luster will be poor when used for a vehicle seat. The 10% modulus value is more preferably 7.5 to 15 N / cm.

Here, the BLC value refers to a value measured by using a tactile sensation measuring device ST300, Laser Softness Tester (manufactured by BLC Leather Technology Center Ltd.).

FIG. 1 schematically shows a cross-sectional structure of a synthetic leather 1 according to an embodiment. In the synthetic leather 1, the skin layer 3 and the protective layer 4 are sequentially laminated on one surface of the fibrous base material 2. As shown in a partially enlarged view in FIG. 1, the protective layer 4 has a wrinkle pattern (uneven pattern) on its surface, and the thickness T1 of the wrinkle pattern peak 5 is 10 to 20 μm. In addition, the thickness T2 of the embossed valley 6 is 3 to 10 μm. The thickness T <b> 1 at the peak portion 5 is the thickness of the protective layer 4 at the top of the peak portion 5. The thickness T <b> 2 in the valley portion 6 is the thickness of the protective layer 4 at the bottom of the valley portion 6. The depth of the embossed pattern on the surface of the protective layer 4 (that is, the difference in height between the top of the peak 5 and the bottom of the valley 6) T3 is not particularly limited, but is preferably 20 to 400 μm. In the illustrated embodiment, the same texture pattern is formed not only on the surface of the protective layer 4 but also on the surface of the skin layer 3 therebelow.

<Fiber base material>
The fibrous base material used for the synthetic leather of this embodiment is a circular knitted fabric having a basis weight of 250 to 350 g / m ² . By using the circular knitted fabric, the resultant synthetic leather has a good elongation balance, and when used for a vehicle seat, it becomes a synthetic leather having a good finish. Further, when the weight per unit area is 250 to 350 g / m ² , a synthetic leather having sufficient durability for automobile interior use, in particular, wear resistance and bending resistance can be obtained.

When the basis weight of the fibrous base material is less than 250 g / m ² , the thickness of the synthetic leather becomes thin. For example, when used for a vehicle seat, the thread of the seat sewing portion does not bite into the synthetic leather, and the sewing thread is synthetic leather. It comes out on the surface and looks bad. When the basis weight exceeds 350 g / m ² , the rigidity of the synthetic leather becomes high, and the sheet tension is poor.

The fibrous base material used in this embodiment preferably has a constant load elongation (measured according to the JIS-L1096 method) of 20 to 40% in the vertical direction and 30 to 50% in the horizontal direction. More preferably, the direction is 25 to 35% and the horizontal direction is 35 to 45%. Here, the vertical direction and the horizontal direction are the vertical direction and the horizontal direction when the fibrous base material is knitted.

By making the constant load elongation rate of the fibrous base material within the above range, the obtained synthetic leather has good elongation, and when used for a vehicle seat, it becomes a synthetic leather with good finish. More specifically, by increasing the constant load elongation rate to 20% or more in the vertical direction and 30% or more in the horizontal direction, the resulting synthetic leather will have better elongation and improve the tension when used in vehicle seats. Can do. Moreover, the wear resistance requested | required of a vehicle seat can be improved by setting it as 40% or less of a length direction, and 50% or less of a horizontal direction.

The kind of fiber used for the fibrous base material is not particularly limited, and examples thereof include conventionally known fibers such as natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers, and two or more of these are combined. It may be. In addition, a fiber base material that has been subjected to dry coagulation or wet coagulation by applying or impregnating a conventionally known solvent-based or water-based polymer compound such as polyurethane resin or a copolymer thereof can also be used. Of these, synthetic fibers, particularly polyester fibers, are preferably used from the viewpoint of strength and processability.

The shape of the fiber used for the fibrous base material is not particularly limited, and may be either a long fiber or a short fiber. The cross-sectional shape of the fiber is not particularly limited, and may be not only a normal round shape but also a flat shape, a triangular shape, a hollow shape, a Y shape, a T shape, a U shape, and the like.

The form of the yarn used for the fibrous base material is not particularly limited, and may be any of filament yarn (long fiber yarn) and spun yarn (short fiber yarn), and further, long fiber and short fiber. Long and short composite spun yarns may be combined. The filament yarn may be twisted as necessary, and may be imparted with stretchability and bulkiness by false twisting or fluid disturbance treatment.

The fineness of the yarn used for the fibrous base material is preferably 110 to 330 dtex, and particularly preferably 220 to 275 dtex. When the fineness is 110 dtex or more, the abrasion resistance of the obtained synthetic leather can be improved. Moreover, when the fineness is 330 dtex or less, it is easy to control the elongation balance of the fibrous base material, and the texture is difficult to become coarse and hard. Therefore, the elongation balance and texture of the obtained synthetic leather can be improved. it can.

The single yarn fineness of the yarn used for the fibrous base material is preferably 1 to 4 dtex from the viewpoint of improving the adhesion between the fibrous base material and the polyurethane resin layer.

As the knitting structure of the circular knitted fabric used as the fibrous base material, a conventionally known knitting structure can be used. Among circular knitted fabrics, double-sided knitting (two rubber knittings) from the point that it is dense and has a solid feeling, is rich in elasticity and elasticity, and is stable without curling (the end of the fabric curls) Rubber knitted fabrics that are made to fit together), or various knitted fabrics by applying a combination of tuck, miss, knit to double-sided knitting.

Furthermore, the fibrous base material of the present embodiment has a so-called width and / or width in a heat treatment step such as a heat setter after shrinking the circular knitted fabric by a dyeing step at high temperature and high pressure from the viewpoint of stretchability. It is preferable to put in. The desired stretchability can be obtained by adjusting the density of the circular knitted fabric through these steps.

<Skin layer>
The synthetic leather according to the present embodiment is formed by laminating a skin layer made of a polyurethane resin on the surface of the fibrous base material described above. The skin layer is a general term for a polyurethane resin layer formed on the surface of a fibrous base material, and is composed of at least one resin layer, but can be composed of two or more resin layers having the same or different composition. For example, the skin layer may be composed of a first polyurethane resin layer and a second polyurethane resin layer as an adhesive layer for bonding the first polyurethane resin layer to the fibrous base material.

As the polyurethane resin used for the skin layer, the same polyurethane resin used for conventionally known synthetic leather can be used. The type and layer structure of the polyurethane resin are not particularly limited.

Examples of the polyurethane resin include polyether-based polyurethane resins, polyester-based polyurethane resins, and polycarbonate-based polyurethane resins. These can be used alone or in combination of two or more. Of these, polycarbonate-based polyurethane resins are preferable from the viewpoint of flame retardancy, durability, and light resistance. The form of the polyurethane resin can be used regardless of whether it is solventless (solvent-free), hot-melt, solvent-based, or water-based. And may be appropriately selected depending on the application.

For polyurethane resins, urethane curing agents, urethanization catalysts, silane coupling agents, fillers, thixotropic agents, tackifiers, waxes, heat stabilizers, light-resistant stabilizers, fluorescent whitening agents, foaming, as necessary Agent, thermoplastic resin, thermosetting resin, dye, pigment, flame retardant, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, oil repellent, hollow foam, crystal water-containing compound, water absorbing agent Optional components such as hygroscopic agents, deodorants, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, pigment dispersants, inert gases, antiblocking agents, antihydrolysis agents, etc. One species can be used alone, or two or more species can be used in combination. Especially, it is preferable to use a urethane hardening | curing agent and a urethanization catalyst in order to reduce the process load and to improve the physical property of synthetic leather.

The thickness of the skin layer made of the polyurethane resin is preferably 100 to 300 μm, more preferably 180 to 220 μm. When the thickness is 100 μm or more, the wear resistance can be improved. Moreover, when the thickness is 300 μm or less, the BLC value of the synthetic leather can be increased to make it hard to become hard, and when it is used for a vehicle seat, the finish can be improved.

The skin layer preferably has a wrinkle pattern (uneven pattern) on its surface. That is, it is preferable that a protective layer having a specific thickness, which will be described later, be formed on the surface of the skin layer having a texture pattern. The wrinkle pattern of the protective layer is formed by the wrinkle pattern of the skin layer, and is preferably formed so as to emphasize the unevenness of the wrinkle pattern of the skin layer due to the specific thickness relationship described later.

<Protective layer>
The synthetic leather of the present embodiment is a surface layer of the above-mentioned polyurethane resin that is the first resin layer laminated on the surface of the fibrous base material, and further, as a second resin layer, a textured peak A protective layer made of a polyurethane resin having a thickness of 10 to 20 μm and a thickness of 3 to 10 μm at the bottom of the embossed pattern is laminated. That is, as for the protective layer, the thickness in the embossed ridge is larger than the thickness in the valley. Synthetic leather by making the thickness of the protective layer different in the above-described range between the ridges and valleys of the texture pattern, that is, by making the ridges that are easily worn into a thick layer and the valleys that are not easily worn into a thin layer. The surface becomes solid and wear resistance is improved. In addition, the texture of the valley that is the starting point of bending becomes soft, and the bending resistance is improved.

The protective layer is a general term for resin layers formed on the surface of the skin layer, and is composed of at least one resin layer, but can be composed of two or more resin layers having the same or different compositions.

If the thickness of the ridges of the wrinkled pattern is less than 10 μm, the wear resistance decreases and the wear resistance for the sheet cannot be maintained. If the thickness of the embossed trough exceeds 10 μm, the hardness of the trough increases, and the flex resistance cannot be maintained when used in a vehicle seat. In addition, by setting the thickness in the valley portion to 3 μm or more, it is possible to suppress the occurrence of coating spots and maintain the appearance quality. As for the thickness of the protective layer, it is more preferable that the thickness at the peak portion of the embossed pattern is 13 to 17 μm, and the thickness at the valley portion of the embossed pattern is 5 to 7 μm. Here, the thickness of the protective layer is an average value of measured values at arbitrary 10 locations.

The polyurethane resin used for forming the protective layer is not particularly limited, and examples thereof include a polyether polyurethane resin, a polyester polyurethane resin, a polycarbonate polyurethane resin, and the like. It can be used in combination of more than one species. Of these, polycarbonate polyurethane resins are preferable from the viewpoint of durability and light resistance. The form of the polyurethane resin can be used regardless of whether it is solventless (solvent-free), hot-melt, solvent-based, or water-based. And may be appropriately selected depending on the application.

For the polyurethane resin, if necessary, the urethanization catalyst, silane coupling agent, filler, thixotropic agent, tackifier, wax, heat stabilizer, light resistance stabilizer, as long as the physical properties of the polyurethane resin are not impaired. , Fluorescent brightening agent, thermoplastic resin, thermosetting resin, dye, pigment, flame retardant, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, oil repellent, hollow foam, crystal water containing Arbitrary compounds, water absorbents, moisture absorbents, deodorants, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, pigment dispersants, inert gases, antiblocking agents, hydrolysis inhibitors, etc. A component can be used individually by 1 type or in combination of 2 or more types.

The mass per unit area (dry adhesion amount) of the polyurethane resin layer including the skin layer (first resin layer) and the protective layer (second resin layer) is preferably 100 to 280 g / m ² , more It is preferably 150 to 200 g / m ² . By setting the dry adhesion amount of the polyurethane resin layer to 100 g / m ² or more, the wear resistance can be improved. By setting the dry adhesion amount of the polyurethane resin layer to 280 g / m ² or less, it is possible to suppress a decrease in the BLC value of the synthetic leather and improve the texture.

In the synthetic leather according to the embodiment, the mass (per unit area) of the polyurethane resin layer that combines the skin layer and the protective layer with respect to the mass of the fibrous base material (mass per unit area, that is, the basis weight). The mass) is preferably 0.4 to 0.8 times. When the mass ratio of the resin layer / fibrous substrate is 0.4 times or more, the wear resistance is improved. Moreover, when this mass ratio is 0.8 times or less, the fall of a BLC value is prevented and a texture improves. The mass ratio is more preferably 0.5 to 0.7 times.

<Manufacturing method>
Next, the manufacturing method of the especially preferable form is demonstrated about the synthetic leather which concerns on this embodiment. That is, the manufacturing method of the synthetic leather of this embodiment is not specifically limited, For example, the following method can be mentioned.

A composition containing a polyurethane resin is applied to a releasable substrate, and if necessary, heat treatment and aging treatment are performed to form a first polyurethane resin layer constituting a part of the skin layer. Next, an adhesive for forming a second polyurethane resin layer is applied to the surface of the first polyurethane resin layer, and the adhesive is stuck to a fibrous base material in a state where the adhesive has a viscosity. If necessary, after heat treatment and aging treatment, the releasable base material is peeled off to obtain a laminate of the fibrous base material and the skin layer (layer comprising the first and second polyurethane resin layers). Next, a composition containing a polyurethane resin is applied to the surface of the skin layer of the laminate, and if necessary, a protective layer is formed by heat treatment and aging treatment. Thus, in the synthetic leather according to one embodiment, the skin layer is a layer formed by applying a polyurethane resin composition to a releasable substrate and peeling the releasable substrate, and the protective layer is The layer is formed by applying a polyurethane resin composition to the surface of the skin layer.

As a method for applying the polyurethane resin composition to the releasable substrate, various conventionally known methods can be adopted and are not particularly limited. Examples thereof include a method using an apparatus such as a reverse roll coater, a spray coater, a roll coater, a gravure coater, a kiss roll coater, a knife coater, a comma coater, or a T-die coater. Especially, the application | coating by a knife coater or a comma coater is preferable at the point that formation of a uniform thin film layer is possible. What is necessary is just to set the application | coating thickness of a polyurethane resin composition suitably according to the thickness of a skin layer.

The releasable base material is not particularly limited, and may be any base material having releasability with respect to the polyurethane resin or a base material subjected to a release treatment. For example, release paper, release treatment cloth And water repellent cloth, olefin sheet or film made of polyethylene resin or polypropylene resin, fluororesin sheet or film, and plastic film with release paper. The releasable base material may have a concavo-convex pattern obtained by inverting the leather-like texture pattern. By using such a releasable base material, it is possible to impart design properties to the surface of the synthetic leather. it can. The depth of the concavo-convex pattern of the releasable substrate (that is, the difference in height between the bottom of the concave portion and the top of the convex portion) is not particularly limited, but is preferably 20 to 400 μm.

Next, heat treatment is performed as necessary. The heat treatment is performed to evaporate the solvent in the polyurethane resin composition and dry the resin. Further, when a cross-linking agent that causes a cross-linking reaction by heat treatment or when using a two-component curable resin, the reaction is promoted to form a film having sufficient strength. The heat treatment temperature is preferably 50 to 150 ° C, more preferably 60 to 120 ° C. By setting the heat treatment temperature to 50 ° C. or more, the heat treatment time can be shortened, the process load can be reduced, and the crosslinking of the resin can be promoted to improve the wear resistance. In addition, by setting the heat treatment temperature to 150 ° C. or less, the texture of the synthetic leather becomes difficult to become coarse and hard. The heat treatment time is preferably 2 to 20 minutes, more preferably 3 to 10 minutes. By setting the heat treatment time to 2 minutes or longer, the resin can be sufficiently crosslinked to improve the wear resistance. Further, by setting the heat treatment time to 20 minutes or less, the processing speed can be increased and the process load can be reduced.

When a hot melt resin is used as the polyurethane resin, it can be formed by applying a heat-melted resin to the releasable substrate and then cooling, and no heat treatment is required.

Further, an aging treatment is performed as necessary to complete the above reaction. Thus, the first polyurethane resin layer constituting a part of the skin layer is formed on the releasable substrate.

Next, an adhesive is applied to the surface of the first polyurethane resin layer formed on the releasable base material, and is bonded to the fibrous base material. If necessary, heat treatment and aging treatment are performed, and then releasability is achieved. The base material is peeled off to obtain a laminate of the fibrous base material and the skin layer.

Finally, a polyurethane resin composition is applied to the surface of the skin layer of the laminate to form a protective layer.

As a method of applying the polyurethane resin composition for the protective layer to the surface of the skin layer, various conventionally known methods can be adopted and are not particularly limited. Examples thereof include a method using an apparatus such as a reverse roll coater, a spray coater, a roll coater, a gravure coater, a kiss roll coater, a knife coater, a comma coater, or a T-die coater. Especially, the application | coating by a roll coater is preferable at the point that it is easy to control to desired thickness. What is necessary is just to set the application | coating thickness of this polyurethane resin composition suitably according to the thickness of the said protective layer.

In this case, the viscosity (20 ° C.) of the polyurethane resin composition is preferably 1000 to 3000 cps (centipoise), more preferably 1500 to 2500 cps. By using the polyurethane resin composition having the above viscosity, the desired thickness can be obtained, that is, the thickness at the embossed portion of the embossed pattern can be made larger than the thickness at the recessed portion of the embossed pattern. If the viscosity is less than 1000 cps, the resin flows into the valleys on the surface of the skin layer after application, the valleys of the protective layer are thicker than the peaks, and the flexibility may be significantly reduced. If the viscosity exceeds 3000 cps, the resin does not enter the valleys on the surface of the skin layer, resulting in coating spots, which may impair the appearance quality.

Further, an aging treatment is performed as necessary to complete the above reaction. Thus, the synthetic leather according to this embodiment is obtained.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. “Parts” in the examples are based on mass. Each measurement / evaluation method is as follows.

[Constant load elongation of fibrous base material]
The measurement was performed according to JIS-L1096 method. That is, three test pieces each having a width of 50 mm and a length of 250 mm were sampled from the fibrous base material in the vertical direction and the horizontal direction. The test piece is marked with a score of 100 mm intervals at the center in the length direction. Under conditions of room temperature 20 ± 2 ° C. and humidity 65 ± 5% RH, the test piece was fastened to a tensile tester, and a weight including a fastening tool and having a total mass of 8 kg was attached to the lower part of the test piece. The test piece was allowed to stand for 10 minutes with the weight suspended, and the gauge interval (L) with the weight suspended was measured. The constant load elongation (%) was determined by the following formula. Results are expressed as average values.
Constant load elongation (%) = (L-100) / 100 × 100

[Thickness of each layer]
The thickness of the skin layer (first polyurethane resin layer, second polyurethane resin layer) and protective layer is a vertical cross section of synthetic leather with a microscope (Digital HF microscope VH-8000, manufactured by Keyence Corporation). Observing, measuring the thickness at any 10 locations, and calculating the average value. About the thickness of a protective layer, the thickness in a peak part is an average value of the thickness in the peak of arbitrary 10 peak parts, and the thickness in a valley part is the average of the thickness in the bottom of arbitrary 10 peak parts. Value.

[BLC value]
One piece of a 150 mm square test piece was collected from the obtained synthetic leather, and a strain measurement value (BLC value) when it was pushed in with a load of 500 g using an ST300 Laser Softness Tester (manufactured by BLC Leather Technology Center Ltd.). Was measured. A larger strain measurement value indicates a softer texture.

[10% modulus]
Three test pieces having a width of 30 mm (B) and a length of 200 mm were sampled from the obtained synthetic leather and subjected to a tensile tester (trade name “Autograph” under the conditions of room temperature 20 ± 2 ° C. and humidity 65 ± 5% RH. AG-X "(manufactured by Shimadzu Corporation) with a gripping interval of 100 mm, pulling at a pulling speed of 200 mm / min, and a stroke distance of 10 mm (ie, 10% extension) (P) And 10% modulus value was calculated by the following formula. The results are shown as an average of 3 points. It shows that it is so flexible that a 10% modulus value is small.
10% modulus value (N / cm) = P (load when the stroke distance becomes 10 mm · N) / B (test specimen width · cm)

[Abrasion resistance]
From the obtained synthetic leather, a test piece was taken from each of the vertical and horizontal directions with a width of 70 mm and a length of 300 mm, and a urethane foam with a width of 70 mm, a length of 300 mm and a thickness of 10 mm was attached to the back side. It was. A wire having a diameter of 4.5 mm was placed at the center of the lower surface of the urethane foam, and a load of 9.8 N was applied to a friction element covered with a cotton cloth in parallel with the wire. The frictional wear was 20,000 times of reciprocating wear at a speed of 60 reciprocations / minute between 140 mm on the surface of the test piece. The appearance after abrasion was evaluated according to the following criteria.
○: A trace of wear can hardly be confirmed △: A trace of wear can be confirmed, but the fibrous base material is not exposed ×: A trace of wear can be confirmed, and the fibrous base material is exposed

[Flexibility]
A test piece having a width of 45 mm and a length of 70 mm was taken from each of the obtained synthetic leathers in the vertical and horizontal directions. The test piece is folded in half from the center of the short side with the surface facing up. After being bent 100,000 times at room temperature with a bending resistance tester specified in JIS K6545, it was removed from the clamp and a pass / fail judgment was made. The appearance after bending was evaluated according to the following criteria.
○: Bent traces can hardly be confirmed △: Bent traces can be confirmed and the bent part is whitened ×: Abnormalities such as cracks have occurred on the skin surface due to bending

[Sewing properties]
A test piece of A4 size (width about 20 cm, length about 20 cm) was sampled from the synthetic leather and 8 mm thick urethane foam (density: 0.04 g / cm ³ ) was placed on the back side. The test piece and the urethane foam were folded together so as to match the urethane foam, and a position 5 mm from the folding line was sewn under the following sewing conditions.
Stitch type …… Main seam Stitch pitch …… 5mm
Sewing thread type and count …… Nylon # 8 for both upper and lower threads
Type and count of sewing needle: JIS B9076 DBX1 No. 23 The state of the sewing part was determined according to the following criteria.
○: The sewing thread bites into the surface of the synthetic leather, the surface is rounded and distorted, and is excellent in sewing properties. Is slightly inferior to the sewing property. ×: The surface of the synthetic leather is not distorted at all, and the sewing thread is exposed on the surface, so that the sewing property is inferior.

[Sheet finish]
Two test pieces A having a diameter of 10 cm and two test pieces B having a size of 15 cm square were collected from the obtained synthetic leather. The vertical direction of the test piece B was sewn to the peripheral edge of the circular test piece A as shown in FIG. Similarly, the test piece A and the test piece B were sewn together in the horizontal direction. Sewing was performed under the following conditions.
Stitch type …… Main seam Stitch pitch …… 5mm
Sewing thread type and count …… Nylon # 8 for both upper and lower threads
Type and count of sewing needle: JIS B9076 DBX1 No. 23 After sewing, as shown in Fig. 2 (b), the condition when the test piece is turned over so that the synthetic leather surface is outside is judged according to the following criteria did.
○: No wrinkle is generated in either of the circular test piece A and the test piece B, and the finish is excellent. Δ: Wrinkle is generated in either the circular test piece A or the test piece B. X: Slightly inferior in projecting property ×: Wrinkles are generated in both the circular specimen A and the specimen B and inferior in projecting property

[Appearance]
The surface of the obtained synthetic leather (the surface of the protective layer) is visually confirmed, and “×” is assumed that the protective layer is not uniformly formed on the embossed valleys and the appearance is inferior. And those having no such coating spots were evaluated as “◯” as having excellent appearance.

[Example 1]
・ Prescription 1:
Polycarbonate-based polyurethane resin 100 parts (Crisbon NY-328, solid content 20%, manufactured by DIC Corporation)
Dimethylformamide (DMF) 40 parts Carbon black pigment 15 parts (DIALAC BLACK L-1770S, solid content 20%, manufactured by DIC Corporation)
Cross-linking agent 2 parts (Bernock DN950, solid content 50%, manufactured by DIC Corporation)
The viscosity was adjusted to 2000 cps (23 ° C.).

・ Prescription 2:
Polycarbonate-based polyurethane resin 100 parts (RU-40-350, solid content 40%, manufactured by Star Japan Co., Ltd.)
Smoothing agent 5 parts (HM-183, solid content 30%, manufactured by Star Japan Co., Ltd.)
Cross-linking agent 2 parts (XR-78-017, solid content 50%, manufactured by Star Japan Co., Ltd.)
Thickener 0.1 part (DF-2569, solid content 50%, manufactured by Star Japan Co., Ltd.)
The viscosity was adjusted to 1500 cps (20 ° C.).

The polyurethane resin composition (solid content 15%) prepared according to the above-mentioned prescription 1 is applied to release paper (R-51, manufactured by Lintec Corporation) having a leather-like texture pattern (irregular pattern) with a comma coater The film was applied in a sheet form so that the thickness (wet) was 150 μm, and heat-treated at 100 ° C. for 3 minutes in a dryer to form a first polyurethane resin surface layer constituting a part of the skin layer. The dry adhesion amount of the first polyurethane resin layer was 28 g / m ² and the thickness was 30 μm.

Next, a urethane polyisocyanate prepolymer (NH230, solid content: 100%, manufactured by DIC Corporation) is applied as a second polyurethane resin layer on the first polyurethane resin layer with a comma coater. was applied to the sheet-like so that the 150 [mu] m, the urethane circular knit fabric of the state where the polyisocyanate prepolymer has a consistency (duplex ed, 220 dtex / 72f, basis weight 300 g / ^{m 2,} constant load elongation: vertical 35%, width 42%) and mangled with a load of 5 kg / m ² . Next, after aging treatment for 3 days in an atmosphere at a temperature of 23 ° C. and a relative humidity of 65%, the release paper was peeled off to obtain a laminate of the fibrous base material and the skin layer. The dry adhesion amount of the second polyurethane resin layer was 150 g / m ² and the thickness was 173 μm. The thickness of the skin layer including the first polyurethane resin layer and the second polyurethane resin layer was 203 μm, and the dry adhesion amount was 178 g / m ² .

Next, a polyurethane resin composition (solid content 40%) having a viscosity adjusted to 1,500 cps according to Formula 2 was applied to the surface of the skin layer of the obtained laminate with a roll coater at a wet coating amount of 30 g / m ² . And it heat-processed for 3 minutes at 100 degreeC with dryer, the protective layer was formed, and the synthetic leather for motor vehicles based on an Example was obtained. The dry adhesion amount of the protective layer was 11.9 g / m ² .

The obtained synthetic leather has a 10% modulus value of 7 N / cm, a BLC value of 4.8, a thickness of the protective layer at the ridge portion of the textured pattern of 15 μm, a thickness of the textured pattern at the valley portion of 7 μm, The mass of the polyurethane resin layer in which the skin layer and the protective layer were combined with respect to the mass was 0.63 times.

[Examples 2 to 7], [Comparative Examples 1 to 4]
Synthetic leather was obtained in the same procedure as in Example 1 except that some configurations were changed according to Table 1. Specifically, in Example 2, the formulation 3 having a viscosity of 3000 cps was used as the polyurethane resin composition forming the protective layer, and in Example 3, the formulation 4 having a viscosity of 1000 cps was used. In Examples 4 and 5, a circular knitted fabric (double-sided knitting, 275 dtex / 96f, basis weight 345 g / m ² , constant load elongation: 30% vertical, 37% horizontal) was used as the fibrous base material, and the second polyurethane resin The coating thickness (wet) of the urethane polyisocyanate prepolymer (NH230, manufactured by DIC Corporation) forming the layer was 230 μm in Example 4 and 100 μm in Example 5. In Example 6, the application thickness (wet) of the urethane polyisocyanate prepolymer (NH230, manufactured by DIC Corporation) forming the second polyurethane resin layer was 80 μm. In Example 7, a circular knitted fabric (double-sided knitted fabric, 167 dtex / 144f, basis weight 255 g / m ² , constant load elongation: vertical 38%, horizontal 47%) was used as the fibrous base material. In Comparative Example 1, a circular knitted fabric (double-sided knitting, 110 dtex / 36 f, basis weight 180 g / m ² , constant load elongation: 43% vertical, 52% horizontal) was used as the fibrous base material. A circular knitted fabric (double-sided knitted fabric, 330 dtex / 96 f, basis weight 400 g / m ² , constant load elongation: vertical 25%, horizontal 30%) was used as the substrate. In Comparative Example 3, Formulation 5 having a viscosity of 500 cps was used as the polyurethane resin composition for forming the protective layer, and in Comparative Example 4, Formulation 6 having a viscosity of 3500 cps was used.

The results are shown in Table 1. The synthetic leathers of Examples 1 to 7 have excellent seating properties suitable for vehicle seats, excellent sewing properties, and resistance to vehicle seats. It had wear and bending resistance. On the other hand, in the comparative example 1, since the fabric weight of the circular knitted fabric which is a fibrous base material was small and the thickness of the synthetic leather was thin, it was inferior to sewing property and tension. In Comparative Example 2, the fabric weight of the circular knitted fabric, which is a fibrous base material, is large, and the synthetic leather has high rigidity. In Comparative Example 3, since the thickness of the protective layer was thin at the embossed peak and thick at the trough, it was inferior in wear resistance and flex resistance. In Comparative Example 4, the viscosity of the polyurethane resin composition forming the protective layer was too high, resulting in poor coating, the protective layer was not uniformly formed in the valleys of the textured pattern, and coating spots were generated.

The synthetic leather according to the present invention can be used, for example, for automobile interior materials such as automobile seats, ceiling materials, dashboards, door lining materials or handles, based on its excellent tactile sensation, texture and abrasion resistance.

DESCRIPTION OF SYMBOLS 1 ... Synthetic leather, 2 ... Fiber base material, 3 ... Skin layer, 4 ... Protective layer, 5 ... Mountain part, 6 ... Valley part

Claims

A synthetic leather for automobiles in which a fibrous base material, a skin layer made of polyurethane resin, and a protective layer made of polyurethane resin are sequentially laminated,
The fibrous base material is a circular knitted fabric having a basis weight of 250 to 350 g / m 2 ;
The protective layer has a wrinkle pattern on its surface, the thickness of the protective layer at the wrinkle-shaped peak is 10 to 20 μm, the thickness of the protective layer at the wrinkle-shaped trough is 3 to 10 μm, and the peak Smaller than the thickness at the part,
The BLC value of synthetic leather is 3.8 to 5.5,
The 10% modulus value of the synthetic leather is 5 to 20 N / cm,
Synthetic leather for automobiles.
The composition for automobile according to claim 1, wherein the mass of the polyurethane resin layer including the skin layer and the protective layer is 0.4 to 0.8 times the mass of the fibrous base material. leather.
The synthetic leather for automobiles according to claim 1 or 2, wherein a constant load elongation rate of the fibrous base material is 20 to 40% in the vertical direction and 30 to 50% in the horizontal direction.