JPH08224385A - Skin material sewing method for integratedly formed skin - Google Patents

Abstract

PURPOSE: To manufacture a molding by skin integratedly forming method, with which it is possible to reduce the manufacturing cost and can certainly suppress leakage of resin at the seam of the skin material. CONSTITUTION: A laminate material 1 is formed by laying a slab 12 of foaming plastics on the rear surface of a trim 11, and from this material 1, a developed skin material 21 is prepared by developing a three-dimensional shape of molding into a plane, and a sewing margin 22 having a certain width is provided at the edge of the spread material 21. Thereby, the base end side of the sewing margin 22 is sewn over the whole length in the longitudinal direction in the condition that the trim 11 sides of the margins 22 of adjoining developed skin materials 21 are laminated one over the other, wherein a sewing needle having a diameter of 1mm is used along with a thread having a diameter less than 0.3mm, and the sewing pitch should be set below 2mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of sewing a skin-integrated molding skin material that is sewn in a bag shape and is mounted in a mold before a molding process in order to manufacture a molded product by an integral foam molding method. It is about.

[0002]

2. Description of the Related Art Molded articles such as automobile seats and headrests for such seats are generally manufactured by an integral foam molding method. This integral foam molding method uses synthetic resin,
Cut a sheet of leather or woven product into a plurality of predetermined shapes, sew them together to form a bag-shaped skin material, load this skin material into the mold, and then Is a molding method in which a raw material of a foamable synthetic resin is supplied, and then a predetermined foaming treatment is performed to integrally form a skin material and a pad material therein.

FIG. 8 is a partially enlarged sectional view showing a sewn portion of a molded product manufactured by a conventional integral foam molding method. As shown in this figure, a laminated material 20 conventionally used as a raw material for the skin material 10 includes a trim (surface material) 201 made of a synthetic resin sheet, leather, a woven product or the like, and a laminated material on the back surface of the trim 201. Slab material 202 made of expanded synthetic resin such as urethane resin, and film 20 made of synthetic resin laminated on the slab material 202
A three-layer laminated structure consisting of 3 and 3 was adopted.

The laminated material 20 which is this three-layered laminate
Is cut into a plurality of expanded skin materials 30 each having a predetermined planar shape in which the three-dimensional shape of the molded product is expanded into a plane, and the seam allowances 40 at the edges of these expanded skin materials 30 are bent inward (downward in the drawing). In this state, the seam allowances 40 are laminated with each other, and the base end portion of the seam allowance 40 is sewn by the sewing thread 50 over the entire length in the longitudinal direction, whereby the bag-shaped skin material 10 is formed.

Then, a foaming synthetic resin and a predetermined foaming agent are loaded into the inside of the skin material 10 and then subjected to a foaming treatment by heating or the like, so that the skin material 1
A molded product such as a headrest having a pad material 60 made of a foam is formed inside 0.

[0006]

By the way, in the conventional sewing method for the skin material 10, the sewing needle used for sewing has a thick diameter of about 1.5 mm, and the sewing thread has the same diameter. A needle having a diameter of about 0.5 mm was used, and the sewing pitch, which is the distance between one needle hole and another needle hole adjacent to it, was set to about 5 mm. A large gap is formed between the inner peripheral surface of the hole 401 and the outer peripheral surface of the sewing thread 50 inserted into the needle hole 401, and the expandable synthetic resin that has expanded during the foaming process leaks to the outside from this gap. However, since the sewing pitch is as large as about 5 mm, there is a problem that the foamable synthetic resin leaks from the gap between the seams.

When the above-described leakage occurs, a leak ball 70 in which the foamable synthetic resin is solidified is formed on the seam surface of the skin material 10 of the manufactured molded product, and the leak ball 70 of the molded product is formed. The appearance becomes unsightly, and the product value of the molded product decreases, which is a problem.

In order to eliminate such inconvenience,
JP-A-63-242606 describes the use of expandable yarn containing a water-absorbent synthetic resin as a sewing yarn. Then, using such a thread, the developed skin material 3
No. 0 is sewn, and after the molded product is obtained, moisture is applied to the molded product to expand the expansive thread, and by this expansion, it is formed between the inner peripheral surface of the needle hole and the outer peripheral surface of the sewing thread. It is stated that the gap is closed, and then integral foam molding is performed.

However, JP-A-63-242606
In the method described in the publication, the water is applied by exposing the sewn skin material to an atmosphere having a temperature of 80 ° C. and a humidity of 90% for about 1 hour. Since a troublesome moisture absorption treatment is added to the manufacturing process of the molded product, the manufacturing of the molded product requires more labor and time than ever before, and there is a problem that the manufacturing cost increases. It was

The present invention has been made in order to solve the above problems, and it is possible to reduce the manufacturing cost and surely suppress the leakage of resin from the seam of the skin material. An object of the present invention is to provide a method of sewing a skin material for integral skin molding which is possible.

[0011]

According to a first aspect of the present invention, there is provided a method for sewing a skin material for integral skin molding, comprising a method for integrally molding a skin, which is sewn in a bag shape for producing a molded product by foaming a foamable synthetic resin. A method for sewing an outer skin material, comprising: a laminated material in which a slab material made of expandable synthetic resin is laminated on a back surface of a surface material, a sewing needle having a diameter of 1 mm or less, and a diameter of 0.3.
It is characterized in that sewing is performed at a sewing pitch of 2 mm or less using a sewing thread of mm or less.

[0012]

According to the method for sewing a skin material for integral skin formation according to claim 1, the laminated material, which is a raw material for the skin material, has a diameter of 1 mm.
Since it is sewn at a sewing pitch of 2 mm or less using a sewing needle having a thickness of mm or less and a sewing thread having a diameter of 0.3 mm or less, the inner peripheral surface of the needle hole and the outer peripheral surface of the sewing thread are different from the conventional one. As the gap between them becomes smaller, the distance between one needle hole and the other needle hole adjacent to it becomes shorter, and the leakage of the foamable synthetic resin during the foaming process is suppressed from these gaps. .

Since the laminated material is formed by laminating only the slab material on the back surface and is not a laminate of synthetic resin film on the slab material as in the conventional case, foaming occurs during foam molding. The expandable and softened expandable synthetic resin penetrates into the slab material without being obstructed by the film layer, and this penetration strengthens the seam allowance, and the reinforced seam allowance protects the sewing thread.

[0014]

EXAMPLE FIG. 1 is a sectional view of a laminated material used in the sewing method of the present invention. As shown in this figure, in the present invention, a two-layer structure including a trim (surface material) 11 and a slab material 12 laminated on the back surface thereof as a skin material of a molded product manufactured by the integral foam molding method. The laminated material 1 of is used. As the trim 11, a soft synthetic resin sheet, synthetic leather, natural leather, or a cloth-like woven product is applied. As the slab material 12, a foamed synthetic resin such as a foamable urethane resin is used. In this embodiment, a synthetic resin sheet having a thickness of about 1 mm is used as the trim 11, and a thickness of 3 mm is provided on the back surface of the trim 11.
A laminated material 1 in which foamed urethane resins having a size of mm to 5 mm are laminated is used.

FIG. 2 is a plan view showing an example of a set of expanded skin materials of a headrest obtained by cutting the laminated material of FIG. 1 into a predetermined shape, and FIG. 3 shows the expanded skin material of FIG. It is a perspective view which shows the skin material of the headrest obtained by sewing. As shown in these figures, the skin material 2 in this embodiment is
Although the one for a headrest of a vehicle seat manufactured by the integral foam molding method is mentioned, the present invention is not limited to the target molded article being a headrest, and a vehicle seat or toy. Any one can be used as long as it is manufactured by the integral foam molding method such as a stuffed animal.

The laminated material 1 is cut into a plurality of developed skin materials 21 in which the three-dimensional shape of the headrest is developed into a planar shape. The width of the outer peripheral edge of each of the expanded skin materials 21 is about 1
A seam allowance 22 of 0 mm is set. Then, as shown in FIG. 5, the seam allowance 22 of one unfolded skin material 21 and the seam allowance 22 of the other unfolded skin material 21 have a thickness of 3 mm or less in a state where the trim 11 portions are in contact with each other. The sewing thread 5 is sewn over the entire length in the longitudinal direction (so-called surface stitching), and the bag-shaped skin material 2 as shown in FIG. 3 is formed.

FIG. 4 is a perspective view showing a state in which the skin material illustrated in FIG. 3 is mounted on a mold. As shown in this figure, the skin material 2 has a frame 3 incorporated therein,
The support rod 31 is attached to the mold 4 in a state of protruding to the outside, and thereafter, a raw material of a foaming synthetic resin such as a foaming urethane resin and a predetermined foaming agent are supplied into the skin material 2 and heated. A headrest is manufactured by subjecting the headrest to a foaming treatment. In the state where the headrest is manufactured, as shown in FIG. 6, a pad material 6 made of a foamable synthetic resin is integrally formed inside the skin material 2, and a seam allowance 22 is embedded in the pad material 6. Has become.

In the present invention, a sewing needle having a diameter of 1 mm or less and a sewing thread 5 having a diameter of 0.3 mm or less are used for sewing the expanded skin material 21. The sewing pitch, which is the distance d (FIG. 5) between the needle hole 23 and another needle hole 23, is set to 2 mm or less. In this embodiment, a polyamide fiber having a diameter of 0.3 mm is used as the sewing thread 5, and a sewing needle having a diameter of 1 mm is used.

By the way, one polyamide fiber (filament) is usually 10 to 30 μm, and its true specific gravity is 1.15. Such a polyamide fiber has a thickness of 0.3.
When the denier number was calculated assuming that the porosity of the sewing thread 5 obtained as a result of the spinning was 51.5 mm, the specific gravity of the sewing thread 5 was 0.90 (1.15 × (1 −
0.215)), therefore, such a sewing thread 5 has a length of 450 m and is approximately 3 g (0.015 cm ² × 3.14 × 450).
Since it is 00 cm × 0.90), the sewing thread 5 made of the polyamide fiber is about 60 denier (3 g / 0.05 g).

In the present invention, the sewing thread 5 is not limited to the one made of polyamide fiber, and the one made of polyester fiber can be preferably used as long as it has an appropriate tensile strength. Also, fibers other than polyester fibers can be used. If the type of fiber changes, the denier number also changes according to the characteristics of the fiber. Therefore, the thickness of the sewing thread 5 of the present invention is 0.3 mm.
Does not unitarily correspond to the denier number, but will be decided each time depending on the type of fiber.

The operation of the present invention will be described below with reference to FIGS. FIG. 5 is a partially cutaway perspective view showing a sewing state of the skin material. Further, FIG. 6 is a partial cross-sectional view of a molded product illustrating the sewn state of the skin material and the embedded state of the seam allowance,
FIG. 7 is a partially enlarged view within the circle of FIG.

As shown in these figures, when one unfolded skin material 21 and the other unfolded skin material 21 are sewn in the longitudinal direction at the base end side of the seam allowance 22, the seam allowance 22 has a base end portion. A needle hole 23 having the same diameter is formed by a sewing needle having a diameter of 1 mm or less.

If the diameter of the sewing needle is 1 mm and the sewing thread 5 having a diameter of 0.3 mm is inserted into the needle hole 23, the inner peripheral surface of the needle hole 23 and the outer peripheral surface of the sewing thread 5 are The cross-sectional area of the gap formed between is 0.71 mm ² (1 mm ²
× 3.14 / 4-0.3mm ² × 3.14 / 4), which is 1.57mm ² (1.5mm ² × 3.14 / 4-0.5m) of the conventional type.
m ² × 3.14 / 4), the gap area is reduced by about 55%. Therefore, leakage of the foamable synthetic resin foamed and expanded during foam molding to the outside from the gap is suppressed by the reduction of the gap area.

Further, the sewing pitch shown in FIG. 4, that is, the distance d between the one needle hole 23 and the other needle hole 23 is 5 m in the conventional case.
It is set to 2 mm, which is 60% smaller than m. As a result, the gap of the seam is very small, so that the leakage of the foamable synthetic resin from this gap is also suppressed. According to the present invention, since the needle hole 23 is made small and the gap between the seams is made small in this manner, a leak ball 70 (FIG. 8) as in the conventional case is formed on the surface of the molded product during the foam molding process. It is not formed, and therefore, the inconvenience of impairing the appearance of the molded product and lowering the commercial value is effectively avoided.

Moreover, since the skin material 2 uses the laminated material 1 having a two-layer structure in which only the slab material 12 is laminated on the back surface of the trim 11, as a raw material, it is immersed in the skin material 2 during foam molding. The entire surface of the slab material 12 portion of the seam allowance 22 is exposed to the foamable synthetic resin having high fluidity during foaming, and as a result, the foamable synthetic resin softened during foaming causes the slab material 12 of the seam allowance 22 to be exposed. The thinned sewing thread 5 is reinforced by the hardened slab material 12,
There is no problem in strength.

Further, the laminated material 1 used in the present invention is not a three-layer structure in which a synthetic resin film is further laminated on the slab material 12 laminated on the trim 11 as in the conventional case, but the slab material is formed on the trim 11. Since only 12 layers are laminated, the material cost is reduced because the film lamination is omitted.

[0027]

As described above, the method of sewing a skin material for integral skin molding according to claim 1 of the present invention is a method of sewing a bag-like integral skin for manufacturing a molded article by foaming a foamable synthetic resin. A method for sewing a molding skin material, comprising a laminated material in which a slab material made of expandable synthetic resin is laminated on the back surface of a surface material, a sewing needle having a diameter of 1 mm or less, and a diameter of 0.3 mm or less. The sewing thread is configured to be sewn at a sewing pitch of 2 mm or less.

Therefore, the gap between the inner peripheral surface of the needle hole and the outer peripheral surface of the sewing thread becomes smaller than in the conventional case, and the distance between one needle hole and another needle hole adjacent thereto becomes shorter, That is, the foaming synthetic resin is prevented from leaking to the outside from these gaps during foam molding. As a result, leak balls are not formed in the seams of the skin material, and the appearance of the molded product is not easily unsightly suppressed, which is extremely convenient for improving the commercial value.

The laminated material, which is a raw material for the skin material, is formed by laminating only the slab material on the back surface, and is not formed by further laminating a synthetic resin film on the slab material as in the conventional case. Foaming synthetic resin foamed and expanded during molding penetrates into the slab material without being obstructed by the film layer, the seam allowance is strengthened by this intrusion, and the sewing thread is protected by the strengthened seam allowance, and as a result,
The thinning of the sewing thread is effectively compensated for, and the occurrence of the breakage of the seam of the skin material is effectively suppressed.

Further, the laminated material is cheaper than the conventional one because the film is not laminated, which is convenient in reducing the material cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a laminated material used in a sewing method of the present invention.

FIG. 2 is a plan view showing an example of a set of developed skin materials of a headrest obtained by cutting the laminated material of FIG. 1 into a predetermined shape.

FIG. 3 is a perspective view showing an example of a skin material of a headrest obtained by sewing the developed skin material of FIG.

FIG. 4 is a perspective view illustrating a state in which the skin material of FIG. 3 is attached to a mold.

FIG. 5 is a partially cutaway perspective view illustrating a sewn state of a skin material.

FIG. 6 is a cross-sectional view illustrating a sewn state of a skin material.

FIG. 7 is a partially enlarged view of a circle in FIG.

FIG. 8 is a partially enlarged sectional view showing a sewn portion of a molded product manufactured by a conventional integral foam molding method.

[Explanation of symbols]

 1 Laminated Material 11 Trim (Surface Material) 12 Slab Material 2 Skin Material 21 Expanded Skin Material 22 Seam Allowance 23 Needle Hole 3 Frame 31 Support Rod 4 Mold 5 Sewing Thread 6 Pad Material

Claims (1)

[Claims] 1. A method of sewing a skin-integrating skin material for forming a bag, which is sewn in a bag shape for producing a molded product by foaming a foamable synthetic resin, wherein a foamable synthetic resin slab material is provided on the back surface of the surface material. Of a laminated material formed by laminating a sewing needle having a diameter of 1 mm or less and a sewing thread having a diameter of 0.3 mm or less at a sewing pitch of 2 mm or less. Sewing method.