JP6387006B2 - Synthetic leather with openings - Google Patents

Description

  The present invention relates to a synthetic leather having an opening. Specifically, the present invention relates to a synthetic leather having an opening that can provide sufficient strength even when used for a vehicle interior material.

  Conventionally, the surface of synthetic leather is covered with a resin layer. Therefore, when used on a vehicle interior material, particularly when used for a seating surface, sweating and stickiness occurs due to sweating when sitting for a long time. There is a problem.

On the other hand, generally, an attempt is made to solve the stuffiness and stickiness by forming an opening in leather by perforating (for example, Patent Document 1) and improving the air permeability of the leather. In synthetic leather for vehicle interior materials, the air permeability required to solve the stuffiness and stickiness is considered to be 60 mL / cm ² · sec or more. However, synthetic leather that satisfies this requirement has sufficient strength for vehicle interior materials. In particular, the tensile strength and tear strength cannot be obtained. In other words, there is a problem that it is impossible to eliminate both stuffiness and stickiness and strength.

Japanese Patent Laid-Open No. 11-209800

  The present invention provides a synthetic leather having sufficient strength for use as an interior material for a vehicle even if it is a synthetic leather having an opening.

  The synthetic leather which concerns on embodiment of this invention is a synthetic leather which a polyurethane resin layer is provided on the fibrous base material which consists of a tricot knitted fabric knitted by 3 or more sheets, and has a some opening part. The yarn constituting the tricot knitted fabric is 84 dtex or more. The knitting structure knitted by the front yarn of the tricot knitted fabric is a cord knitting structure having three or more underlaps, the knitting structure knitted by the middle yarn is a chain knitting structure, and the knitting structure knitted by the back yarn Is a denbi organization or a code organization. The polyurethane resin layer has a thickness of 100 μm or more.

  According to this embodiment, even if it is a synthetic leather which has an opening part, the synthetic leather with sufficient intensity | strength as a vehicle interior material use can be provided.

Schematic sectional view of synthetic leather according to an embodiment Diagram explaining the specimen used for tear strength test

  The synthetic leather according to this embodiment is a synthetic leather in which a polyurethane resin layer is laminated on a fibrous base material and has a plurality of openings. FIG. 1 schematically shows a cross-sectional structure of a synthetic leather 1 according to an embodiment. In the synthetic leather 1, a polyurethane resin layer 3 is provided on one surface of the fibrous base material 2, and air permeability is improved on the surface of the polyurethane resin layer 3 (that is, the front surface of the synthetic leather 1). A plurality of openings 6 are provided. The opening 6 is provided through the polyurethane resin layer 3 and the fibrous base material 2. In this example, the polyurethane resin layer 3 includes a skin layer 4 and an adhesive layer 5, and the skin layer 4 is laminated on the fibrous base material 2 via the adhesive layer 5.

  In the present embodiment, a tricot knitted fabric knitted with three or more sheets is used as the fibrous base material. The tricot knitted fabric is one type of warp knitting, and in this embodiment, a multi-knitted fabric knitted by a tricot knitting machine using three or more rivets (guide bars) is used. The number of ridges should just be 3 or more, and although an upper limit is not specifically limited, Usually, it is 5 or less.

  In the tricot knitted fabric of the present embodiment, the knitted structure knitted by the front yarn is a cord knitted structure having three or more underlaps. This increases the basis weight of the tricot knitted fabric and improves the strength. Furthermore, it is preferable in terms of texture that the cord knitting structure has 5 or less underlaps. Here, the front yarn is a yarn fed from the front rod.

  In the tricot knitted fabric, the knitted structure knitted by the middle yarn is a chain knitted structure. Thereby, the elongation of the tricot knitted fabric is suppressed and the strength is improved. Here, the middle yarn is a yarn fed from a middle rod. When the tricot knitted fabric is knitted with four or more kites, the chain stitch structure may be knitted with yarn fed from at least one middle kite, and other than the chain stitch structure with a plurality of middle kites. These knitting structures may be provided in layers.

  Further, in the tricot knitted fabric, the knitted structure knitted by the back yarn is a denby knitted structure or a cord knitted structure. This increases the basis weight of the tricot knitted fabric and improves the strength. In particular, the cord knitting structure is preferably a cord knitting structure having two or more underlaps, more preferably a cord knitting structure having two or more needles and five or less stitches. Here, the back yarn is a yarn fed from the back rod.

  The fiber material constituting the tricot knitted fabric in the present embodiment is not particularly limited, and conventionally known natural fibers, regenerated fibers, synthetic fibers, semi-synthetic fibers, and the like can be used. These can be used alone or in combination of two or more. Synthetic fibers are preferable as the fiber material from the viewpoint of having strength suitable for vehicle interior materials, and it is preferable to use polyester.

  The shape of the fiber constituting the tricot knitted fabric may be either a long fiber or a short fiber depending on its purpose and specific use. Further, the cross-sectional shape 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, or the like.

  The fineness (hereinafter referred to as single yarn fineness) of the fibers (single fiber) constituting the tricot knitted fabric is preferably 0.7 to 3.5 dtex, and particularly preferably 1.5 to 2.5 dtex. preferable. When the single yarn fineness is 0.7 dtex or more, the strength can be improved. Moreover, when the single yarn fineness is 3.5 dtex or less, the opening property when the opening is formed by drilling can be improved, and the fiber substrate is prevented from being frayed from the opening. be able to.

  The form of the yarn constituting the tricot knitted fabric may be any of spun yarn (short fiber yarn), multifilament yarn, monofilament yarn (above, long fiber yarn), and a combination of long fiber and short fiber. Long and short composite spun yarns may also be used. If necessary, one or a plurality of multifilament yarns may be aligned and twisted, or may be subjected to processing such as false twisting or fluid disturbance processing. Among these, from the viewpoint of strength, particularly tear strength and tensile strength, it is preferable to use a processed yarn that has been subjected to false twisting or fluid disturbance treatment.

  The fineness (total fineness) of the yarn constituting the tricot knitted fabric is 84 dtex or more. When the fineness of the yarn is 84 dtex or more, the strength can be improved. Furthermore, it is preferable from a viewpoint of a texture that it is 250 dtex or less. The yarn constituting the tricot knitted fabric may be the same or different between the front yarn, the middle yarn and the back yarn.

Preferably the basis weight of the tricot knitted fabric is 200~550g / ^{m 2,} more preferably a 250~500g / ^{m 2,} may be 300 to 500 g / ^{m 2.} The strength can be improved when the basis weight is 200 g / m ² or more. An increase in cost can be suppressed when the basis weight is 550 g / m ² or less.

  Further, the tricot knitted fabric in this embodiment preferably has an adhesion index of 350,000 to 850000, and more preferably 400000 to 800000. When the adhesion index is in the above range, the adhesion between the tricot knitted fabric and the polyurethane resin layer is high, the strength is improved, and the texture is good.

The adhesion index of the tricot knitted fabric is calculated by the following formula.
Adhesion index = ((Single yarn fineness of front yarn (dtex) × number of filaments of front yarn) + (Single yarn fineness of middle yarn (dtex) × number of filaments of middle yarn) + (Single yarn fineness of back yarn (dtex)) X number of filaments of the back yarn)) x course density x well density Here, the course density is the number of stitches per inch (25.4 mm) in the warp direction of the tricot knitted fabric, and is course / 25.4 mm. The well density is the number of stitches per inch (25.4 mm) in the weft direction of the tricot knitted fabric, and is well / 25.4 mm.

  Such a tricot knitted fabric can be subjected to pretreatment such as pre-setting and scouring, and color addition as necessary.

  The synthetic leather according to the present embodiment has a polyurethane resin layer provided on a fibrous base material made of tricot knitted fabric, and has a polyurethane resin layer provided directly on the tricot knitted fabric or via an adhesive layer. It is. The polyurethane resin layer may be provided on either the front surface or the back surface of the tricot knitted fabric, but is provided on the back surface in that the surface is flat, the adhesiveness with the polyurethane resin layer is good, and the peel strength is good. It is preferable. Here, the front surface of the tricot knitted fabric is a surface formed by a knitting structure using a front yarn, and the back surface is a surface formed by a knitting structure using a back yarn.

  Specifically, the polyurethane resin liquid is applied directly to one side of the fibrous base material by a method such as knife coating, roll coating, gravure or spraying, followed by dry coagulation or wet coagulation to directly provide the polyurethane resin layer. Also good. Alternatively, after a predetermined polyurethane resin liquid is applied to the releasable substrate by a method such as knife coating, a polyurethane resin layer is prepared by dry coagulation or wet coagulation, and this is crimped to one side of a tricot knitted fabric As a result, the polyurethane resin layer may be provided directly. Alternatively, the polyurethane resin layer may be provided by bonding the polyurethane resin layer prepared on the releasable substrate to one side of the tricot knitted fabric using an adhesive.

  The polyurethane resin constituting the polyurethane resin layer is not particularly limited, and examples thereof include polyether-based polyurethane resins, polyester-based polyurethane resins, and polycarbonate-based polyurethane resins. These may be used alone or in combination of two or more. They can be used in combination. Of these, polycarbonate polyurethane resins are preferred from the viewpoints of wear resistance and light fastness. In addition, the form of the polyurethane resin can be used regardless of whether it is solventless, hot-melt, solvent-based, or water-based, and it can be used regardless of whether it is a one-component type or a two-component curable type. What is necessary is just to select suitably.

  If necessary, the polyurethane resin may contain conventionally known additives such as a colorant, a plasticizer, a stabilizer, a filler, a lubricant, a paint, a foaming agent, a release agent and the like. These can be used singly or in combination of two or more.

  The thickness of the polyurethane resin layer is 100 μm or more, and particularly preferably 150 μm or more. When the thickness of the polyurethane resin layer is 100 μm or more, a decrease in strength of the resultant synthetic leather can be suppressed. From the viewpoint of texture, the thickness of the polyurethane resin layer is preferably 500 μm or less, and more preferably 300 μm or less. When a polyurethane adhesive is used when providing the polyurethane resin layer, the adhesive layer formed by the adhesive also constitutes a part of the polyurethane resin layer. For example, in the example shown in FIG. 1, the polyurethane resin layer 3 includes a skin layer 4 that constitutes the front side of the synthetic leather 1 and an adhesive layer 5. Therefore, in this case, the value including the thickness of the adhesive layer is defined as the thickness of the polyurethane resin layer. Thus, a polyurethane resin layer is a layer which consists of a polyurethane resin formed on a fibrous base material, and is not restricted to 1 layer structure, Two layers or 3 layers or more may be sufficient.

  The synthetic leather according to this embodiment has a plurality of openings. The opening can be formed by a conventionally known means such as needle punching, discharge, or laser irradiation. The opening penetrates from the surface of the polyurethane resin layer to the tricot knitted fabric.

  The ratio of the opening to the front side of the synthetic leather (that is, the front side of the polyurethane resin layer), the opening ratio is preferably 10% or more, more preferably 10 to 20%, and still more preferably 10 to 15 %. When the opening ratio is 10% or more, sufficient air permeability as a vehicle interior material can be obtained. On the other hand, if the aperture ratio is 20% or less, it is excellent in terms of strength.

The shape of the opening is not particularly limited, and can be selected from a geometric pattern such as a circle, a triangle, or a square in consideration of design. From the viewpoint of strength, a round shape is preferable. The size of the opening is preferably 0.19 to 7.07 mm ² (corresponding to an average diameter of 0.5 to 3.0 mm when the opening is round). When the size of the opening is 0.19 mm ² or more, the air permeability of the synthetic leather can be increased, and the effect of suppressing stuffiness and stickiness when sitting for a long time can be enhanced. Moreover, the strength reduction of synthetic leather can be suppressed by being 7.07 mm < ² > or less.

Further, the distribution state (average density) of the openings is preferably 8 to 100 / (25.4 mm) ² . When the average density is 8 pieces / (25.4 mm) ² or more, the air permeability of the synthetic leather can be increased, and the effect of suppressing the stuffiness and stickiness when sitting for a long time can be enhanced. Moreover, when the average density is 100 pieces / (25.4 mm) ² or less, strength reduction of the synthetic leather can be suppressed.

The synthetic leather having such an opening preferably has an air permeability of 60 mL / cm ² · sec or more. The air permeability is more preferably 100 mL / cm ² · sec or more. The upper limit of the air permeability is not particularly limited, and may be, for example, 200 mL / cm ² · sec or less, or 150 mL / cm ² · sec or less.

By configuring as described above, according to the present embodiment, an opening is provided so that the air permeability is 60 mL / cm ² · sec or more, but sufficient strength (tensile for vehicle interior material use) Synthetic leather with strength and tear strength can be provided.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. “Parts” in the examples are based on mass. Moreover, the obtained synthetic leather was evaluated according to the following method.

[Tensile strength]
Three test pieces each having a width of 30 mm and a length of 150 mm were collected in the vertical and horizontal directions. Using a tensile tester Autograph AG-100A (manufactured by Shimadzu Corporation), hold both ends of the test piece with a gripper under conditions of room temperature 20 ± 2 ° C and humidity 65 ± 5% RH. The test piece was broken at a grip width of 30 mm, a grip interval of 100 mm, and a gripper moving speed of 200 mm / min. The maximum load (N / cm) when the test piece broke was measured, and the average value was obtained. If the measured value is 50 N / cm or more, it can be said that the tensile strength is sufficient as a synthetic leather. The larger the value, the better the tensile strength.

[Tear strength]
Three test pieces each having a width of 50 mm and a length of 250 mm were collected from the vertical and horizontal directions. An isosceles trapezoidal mark as shown in FIG. 2 is attached to the test piece, and a 10 mm cut is made in the center of the short side of the mark at a right angle to the side. Using a tensile tester Autograph AG-100A (manufactured by Shimadzu Corporation) under the conditions of room temperature 20 ± 2 ° C. and humidity 65 ± 5% RH, a trapezoidal short side is stretched at a grip interval of 10 mm, and the long side is The test piece was torn at a moving speed of 200 mm / min. The maximum load (N / cm) when the test piece was cut was measured, and the average value was obtained. If the measured value is 100 N / cm or more, it can be said that the tear strength is sufficient as a synthetic leather. The larger the value, the better the tear strength.

[Peel strength]
Three test pieces each having a width of 30 mm and a length of 120 mm are sampled in the vertical and horizontal directions, and the polyurethane resin layer and the fibrous base material are peeled 40 mm from one end of the short side of the test piece. Under conditions of room temperature 20 ± 2 ° C. and humidity 65 ± 5% RH, the polyurethane resin layer and the fibrous base material are sandwiched with a gripper so that there is no slack. ) Was used to peel the polyurethane resin layer at a grip width of 30 mm and a gripper moving speed of 200 mm / min. The maximum load (N / cm) at the time of peeling was measured, and the average value of each was taken as the peeling strength. If the measured value is 8 N / cm or more, it can be said that the peel strength is sufficient as a synthetic leather, and the larger the value, the better the peel strength.

[Air permeability]
The air permeability at room temperature (23 ° C.) was measured according to JIS L1096 8.26.1A method (Fragile type method). The larger the measured value, the higher the air permeability.

[Texture]
The panel was evaluated by tactile sensation and judged according to the following criteria.
(Evaluation criteria)
1 ... Good (flexible)
2 ... Slightly bad (slightly inflexible)
3 ... bad (hard and inflexible)

[Example 1]
Using a 28-gauge tricot knitting machine (HKS3M: manufactured by Nihon Meyer), introduce a full set of 84 dtex / 36f polyester multifilament to the front heel to create a cord knitting structure (underwrap between 3 stitches). Introduce a full set of 84 dtex / 36f polyester multifilament into the heel and introduce a chain knitted structure into the back heel and introduce a full set of 84 dtex / 36f polyester multifilament into the back knitted cord (underwrap between two stitches) ), Respectively, and knitted a tricot knitted fabric. Details of each knitting structure are as shown in Table 1. The obtained tricot knitted fabric was preset at 190 ° C. for 1 minute, dyed and dried at 130 ° C., and finished and set at 150 ° C. for 1 minute.

  A polyurethane resin solution was prepared by adding 40 parts by mass of dimethylformamide to 100 parts by mass of a polycarbonate-based polyurethane resin (Crisbon NY-328 manufactured by DIC Corporation) to adjust the viscosity to about 2000 mPa · s. The polyurethane resin solution was coated on release paper so that the coating thickness was 200 μm, and then dried at 130 ° C. for 2 minutes to obtain a polyurethane resin layer (corresponding to the skin layer).

Polyurethane resin formed as described above by adding 50 parts by mass of dimethylformamide to 100 parts by mass of polycarbonate polyurethane adhesive (Crisbon TA-205 manufactured by DIC Corporation) and adjusting the viscosity to about 4500 mPa · s. After coating on the layer so that the coating thickness was 200 μm, it was dried at 100 ° C. for 1 minute. The obtained adhesive layer and the back surface of the tricot knitted fabric were combined and press-bonded for 1 minute under the condition of 39.2 N / cm ² to obtain a synthetic leather. At this time, the thickness of the polyurethane resin layer (total thickness of the skin layer and the adhesive layer) was 199 μm. The resultant synthetic leather tricot knitted fabric had a course density of 65 courses / 25.4 mm, a well density of 34 wells / 25.4 mm, an adhesion index of 548964, and a basis weight of 347 g / m ² .

The obtained synthetic leather was punched by a punching machine on the surface side of the synthetic leather. By opening a hole, an opening having a size of 1.77 mm ² , an average diameter of 1.5 mm, an average density of 45 / (25.4 mm) ² , and an opening ratio of 12.3% is formed. The synthetic leather of Example 1 was obtained.

  In Examples 2 to 7 and Comparative Examples 1 to 8, synthetic leather was obtained in the same manner as in Example 1 except that a tricot knitted fabric and a polyurethane resin layer were prepared according to Tables 1 and 2. For the yarns in Table 1, “84/36” is 84 dtex / 36f, that is, the yarn fineness is 84 dtex and the number of filaments is 36. In Example 2, a double yarn in which two 84 dtex / 36 f polyester multifilaments were twisted together was used for the front yarn.

  The above-mentioned items were evaluated for the synthetic leathers obtained in Examples and Comparative Examples, and the results are shown in Tables 1 and 2. As shown in Table 1, when it is the synthetic leather of Examples 1 to 7, it has excellent breathability but has sufficient tensile strength and tear strength for use as a vehicle interior material, and peels off. The strength and flexibility were also generally good. From a comparison between Example 1 and Example 3, the back yarn was superior in the cord knitting structure in terms of tensile strength to the denby knitting structure. Further, from the comparison between Example 1 and Example 7, it was more excellent in terms of peel strength that the polyurethane resin layer was provided on the back surface than on the front surface of the tricot knitted fabric.

  As shown in Table 2, in Comparative Examples 1 and 4, the fineness of the yarn constituting the tricot knitted fabric was small, and sufficient strength as a vehicle interior material application could not be obtained. Comparative Example 2 is an underlap cord knitting structure in which the front yarn is between two stitches, Comparative Example 3 is a middle yarn having a Denbi knitting structure, and Comparative Example 6 is a front yarn having a Denbi knitting structure. Since No. 7 was knitted with two sheets without middle yarn, both were inferior in tensile strength and tear strength. In Comparative Example 5, the thickness of the polyurethane resin layer was small, and the tensile strength and tear strength were inferior. In Comparative Example 8, since the knitting structure of the back yarn was insertion, the flexibility was inferior.

  The synthetic leather according to the present invention can be used for automobile interior materials such as automobile seats, ceiling materials, dashboards, door lining materials, and handles.

DESCRIPTION OF SYMBOLS 1 ... Synthetic leather, 2 ... Fiber base material, 3 ... Polyurethane resin layer, 6 ... Opening part

Claims (5)

A synthetic leather provided with a polyurethane resin layer on a fibrous base material composed of a tricot knitted fabric knitted with 3 sheets or more and having a plurality of openings,
The yarn constituting the tricot knitted fabric is 84 dtex or more,
The tricot knitted fabric has a knitted structure knitted by the front yarn, a cord knitted structure having three or more underlaps, a knitted structure knitted by the middle yarn, a chain knitted structure, and a knitted structure knitted by the back yarn. Knitting organization or code organization,
The polyurethane resin layer has a thickness of 100 μm or more,
Synthetic leather. The synthetic leather according to claim 1, wherein an adhesion index represented by the following formula of the tricot knitted fabric is in the range of 350,000 to 850000.
Adhesion index = ((Single yarn fineness of front yarn (dtex) × number of filaments of front yarn) + (Single yarn fineness of middle yarn (dtex) × number of filaments of middle yarn) + (Single yarn fineness of back yarn (dtex)) X number of filaments of back yarn)) x course density (course / 25.4 mm) x well density (well / 25.4 mm)   The synthetic leather according to claim 1 or 2, wherein the knitted structure knitted by the back yarn is a cord knitted structure having two or more underlaps.   The synthetic leather according to any one of claims 1 to 3, wherein the polyurethane resin layer is formed on a back surface of the tricot knitted fabric. The plurality of openings are provided so as to penetrate the polyurethane resin layer and the fibrous base material, and an opening ratio that is a ratio of the openings on the front surface of the polyurethane resin layer is 10% or more. The synthetic leather of any one of 1-4.

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