JP7742702B2 - Sewn products, skin-integrated foam molded products, and manufacturing method of sewn products - Google Patents

Description

This disclosure relates to a sewn product, a manufacturing method thereof, and an integral skin foam molded product in which the sewn product and a foam are integrated.

Conventionally, sewn products made by sewing together multiple cover materials have been known (see, for example, Patent Document 1).

JP 2000-079843 A (paragraph [0013] etc.)

In conventional sewn products, when the covering material has a laminated structure, part of the inner layer of the covering material is pulled out through the seam by the sewing thread, resulting in an unattractive appearance.

The first aspect of the invention, which was made to solve the above problem, is a sewn product made by sewing together multiple skin materials with a laminated structure including an adhesive layer, and the sewing thread that sews the skin materials together is water-repellent.

A second aspect of the invention is the sewn product according to the first aspect, in which the adhesive layer contains a component derived from rubber latex, and the sewing thread is coated with a fluororesin.

A third aspect of the invention is a sewn product according to the first or second aspect, in which the covering materials are sewn together with their outer surfaces overlapping each other and folded in opposite directions at the seams.

A fourth aspect of the invention is a sewn product according to any one of the first to third aspects, wherein the laminated structure of the skin material includes a synthetic leather layer containing polyvinyl chloride resin and a reinforcing layer containing a woven fabric, laminated to the synthetic leather layer via the adhesive layer.

A fifth aspect of the invention is a skin-integrated foam molded product comprising the sewn product according to any one of the first to fourth aspects sewn into a bag shape, and a foam that has been foam-molded within the sewn product and is integrated with the sewn product.

A sixth aspect of the invention is a method for manufacturing a sewn product in which a plurality of surface materials with a laminated structure including an adhesive layer are sewn together to produce a sewn product, and the surface materials are sewn together using a water-repellent sewing thread.

In the first and sixth aspects of the invention, the sewing thread used to sew together the covering materials of the sewn product is water-repellent. This makes it difficult for the inner layer of the covering material, particularly the adhesive layer, to adhere to the sewing thread when the sewing thread penetrates the covering material during sewing, making it difficult for the inner layer to be pulled out of the seam. This prevents the appearance of the sewn product from being compromised.

In the sewn product of the second aspect of the invention, the sewing thread is coated with a fluorine-based resin, which further prevents the adhesive layer from being pulled out by the sewing thread when the adhesive layer contains components derived from rubber latex.

One possible configuration is to sew together the covering materials with their outer surfaces overlapping, and then fold them in opposite directions at the seams. In this case, the seams of the sewn product tend to widen, and the portions of the inner layer of the covering material that are pulled outward by the sewing thread tend to become exposed at the seams, resulting in an unattractive appearance. In contrast, in the third aspect of the invention, the sewing thread is water-repellent, making it difficult for the inner layer to be pulled out by the sewing thread during sewing. This prevents the product from becoming unattractive, even in a configuration in which the inner layer is easily exposed at the seams.

Furthermore, in an integrated skin foam molded product in which a foam is foam-molded inside a bag-shaped sewn product and integrated with the sewn product, the pressure from the foam tends to put tension on the skin material, causing the seams to easily widen and the inner layer of the skin material to easily become exposed through the seams. In contrast, in the fifth aspect of the invention, water-repellent sewing thread is used to sew the skin materials together, making it difficult for the inner layer of the skin material to protrude through the seams, preventing the integrated skin foam molded product from looking unattractive.

According to the fourth aspect of the invention, the covering material is reinforced by having a reinforcing layer containing a woven fabric. Furthermore, by providing a synthetic leather layer containing a polyvinyl chloride resin as the outermost layer, the texture of the covering material can be improved. Furthermore, by bonding the reinforcing layer to the synthetic leather layer, the synthetic leather layer is reinforced and wrinkles can be prevented from forming in the synthetic leather layer.

FIG. 1 is a perspective view of a sewn product and a headrest according to a first embodiment of the present disclosure; 1 is a cross-sectional view of a sewn product and a headrest according to a first embodiment; FIG. 1 is an enlarged cross-sectional view of a sewn product and a headrest in the vicinity of a seam according to a first embodiment; Enlarged cross-sectional view of a sewn product using conventional sewing thread and the area around the seam of a headrest

[First embodiment]
As shown in Fig. 1 , a sewn product 10 according to the first embodiment of the present disclosure is used in a headrest 91 of a vehicle seat 90. As shown in Fig. 2 , the headrest 91 has a configuration in which a core portion 92 made of a foam is covered from the outside with a bag-shaped sewn product 10. In the example of this embodiment, the core portion 92 is made of polyurethane resin, and the headrest 91 is an integrally foam-molded product with a surface in which the core portion 92 is foam-molded within the sewn product 10 and integrated with it.

The sewn product 10 is made by sewing together multiple cover materials 20. The sewn product 10 is formed with an opening for projecting the leg portion 12A of the stay 12 for attaching the headrest 91 to the backrest portion of the vehicle seat 90, as well as an injection port for injecting the raw material for the core portion 92 when molding the core portion 92.

As shown in FIG. 3, the cover materials 20 are sewn together so that the front surfaces 20A of the cover materials 20 that are exposed to the outside of the headrest 91 overlap each other (specifically, the edges of the cover materials 20 are sewn together). The sewn cover materials 20 are folded opposite each other at the seams 21, and the seam allowances 22 between the cover materials 20 are positioned on the inside of the sewn product 10.

The skin material 20 has a laminated structure. In this embodiment, the laminated structure of the skin material 20 is a four-layer structure, and from the front side, it has a synthetic leather layer 31, an adhesive layer 32, a reinforcing layer 33, and a back layer 34.

The synthetic leather layer 31 forms the front surface 20A of the skin material 20 (i.e., the outer surface of the headrest 91), and examples of the synthetic leather layer 31 include those containing polyvinyl chloride resin as a main component.

In this embodiment, the adhesive layer 32 contains a component derived from rubber latex. Examples of the adhesive layer 32 include a layer obtained by blending a tackifier or the like with natural rubber latex or synthetic rubber latex. The adhesive layer 32 may also be one that does not contain a component derived from rubber latex.

The reinforcing layer 33 is made of synthetic or natural fibers, and may be made of, for example, woven or nonwoven fabric. In this embodiment, the reinforcing layer 33 is made of metal cloth.

The back layer 34 is made of, for example, a resin foam molded by slab molding, and in this embodiment, it is made of slab urethane. From the standpoint of adhesion to the core portion 92, it is preferable that the back layer 34 be made of the same resin as the core portion 92.

Here, when commonly used polyester resin sewing thread 48 (see Figure 4) is used as the sewing thread for sewing together the covering materials 20, a problem occurs in that part of the inner layer of the covering material 20, particularly the adhesive of the adhesive layer 32, protrudes from the seam 21, resulting in a poor appearance. Specifically, as shown in Figure 4, such protruding portions 32T of the adhesive are formed at the boundary 25 between the covering materials 20 in correspondence with the seam 21 and are visible. This is particularly noticeable in sewn products in which the sewn covering materials 20 are spread apart so that they are bent to opposite sides at the seam 21. As such, with conventional methods, the poor appearance of the sewn product is likely to result in a high incidence of defective products, and the excessive effort required to remove the protruding portions 32T of the adhesive reduces productivity.

To address this issue, it is conceivable to use, for example, a fuzzy sewing thread to make it easier to seal the seam 21 and prevent parts of the inner layer of the cover material 20 or the core portion 92 from protruding from the seam 21. However, after careful investigation, the inventors of the present application found that when a fuzzy sewing thread made of polyester resin is used, the adhesive of the adhesive layer 32 is more likely to protrude from the seam 21 than when a non-fuzzy thread made of the same polyester resin is used, resulting in a poor appearance. This is thought to be because when a fuzzy sewing thread penetrates the cover material 20, the adhesive of the adhesive layer 32 is more likely to be pulled out from the seam 21. Based on this knowledge, the inventors of the present application conducted extensive research and found that the use of a water-repellent sewing thread 40 can prevent the adhesive from protruding.

Specifically, in this embodiment, the sewing thread 40 used to sew the covering materials 20 together is a thread body (e.g., twisted thread) made of synthetic resin fibers such as polyester, to which a water-repellent coating has been applied. In this embodiment, this coating material is made of a fluorine-based resin, but it may also be made of a silicone-based resin, for example. The fibers making up the thread body may also be natural fibers. Note that the sewing thread 40 does not have to be made water-repellent by a coating; for example, the resin making up the fiber itself may be water-repellent and not be coated with a water-repellent coating.

In this way, in the sewn product 10 of this embodiment, the sewing thread 40 that sews the upholstery materials 20 together is water-repellent. This makes it difficult for the inner layer of the upholstery material 20, particularly the adhesive layer 32, to adhere to the sewing thread 40 when it penetrates the upholstery material 20 during sewing, making it difficult for the inner layer to be pulled out of the seam 21. This prevents the appearance of the sewn product 10 from being impaired.

In addition, decorative stitches 26 may be provided near the seams 21 of the sewn product 10 (see Figure 1). If the decorative stitches 26 are made of thread, it is preferable that this thread also have water-repellent properties.

The sewn product 10 and headrest 91 of this embodiment are manufactured, for example, as follows. First, multiple cover materials 20 are prepared. Specifically, each cover material 20 has a four-layer structure in which, from the front side, a synthetic leather layer 31, an adhesive layer 32, a reinforcing layer 33, and a back layer 34 are laminated as described above.

Next, multiple skin materials 20 are sewn together to create a bag-shaped sewn product 10. The skin materials 20 are sewn together using water-repellent sewing thread 40. As described above, the sewn product 10 is provided with an injection port for injecting the raw material for the core portion 92 and an opening for inserting the leg portion 12A of the stay 12.

Next, with the stay 12 inserted through the sewn product 10, the sewn product 10 and stay 12 are set in a foam molding die for foam molding the core portion 92. Then, foamed polyurethane raw material is injected into the sewn product 10 through the injection port and foamed inside the foam molding die. This forms the foamed polyurethane core portion 92, which becomes integrated with the sewn product 10. The core portion 92 and sewn product 10 are then removed from the foam molding die, yielding a headrest 91 in which the sewn product 10 and core portion 92 are integrated.

As described above, in the sewn product 10 of this embodiment, the sewing thread 40 that sews the covering materials 20 together is water-repellent. This makes it difficult for the inner layer of the covering material 20, particularly the adhesive layer 32, to adhere to the sewing thread 40 when it penetrates the covering material 20 during sewing, making it difficult for the inner layer to be pulled out of the seam 21. This prevents the appearance of the sewn product 10 from being poor. As a result, it is possible to reduce the occurrence of defective products with poor appearances compared to conventional sewn products, and it is also possible to reduce the amount of work required to trim off the adhesive that protrudes from the seam 21, thereby improving productivity.

In this embodiment, the sewing thread 40 is coated with a fluorine-based resin, which can further prevent the adhesive layer 32 from being pulled out by the sewing thread when the adhesive layer 32 contains components derived from rubber latex.

In addition, in this embodiment, the covering materials 20 are sewn together with their front surfaces 20A overlapping. The covering materials 20 are then folded opposite each other at the seams 21. In this case, the seams 21 of the sewn product 10 tend to widen, and the portions of the internal layer of the covering material 20 (particularly the adhesive layer 32) that are pulled outward by the sewing thread 40 tend to become exposed through the seams 21, which can result in an unattractive appearance. In contrast, in the sewn product 10 of this embodiment, the sewing thread 40 is water-repellent, which makes it difficult for the internal layer (particularly the adhesive layer 32) to be pulled out by the sewing thread 40. Therefore, even in a configuration in which the internal layer of the covering material 20 is easily exposed through the seams 21, it is possible to prevent the appearance from becoming unattractive.

Furthermore, in an integrated skin foam molded product in which a foam is foam-molded inside a bag-shaped sewn product and integrated with the sewn product, pressure from the foam tends to apply tension to the skin material 20, causing the seams 21 to easily widen and the inner layer of the skin material 20 to easily become exposed through the seams 21. In contrast, in the sewn product 10 of this embodiment, water-repellent sewing thread 40 is used to sew the skin materials 20 together, making it difficult for the inner layer of the skin material to protrude through the seams, preventing the integrated skin foam molded product from looking unattractive.

In addition, in this embodiment, the covering material 20 has a reinforcing layer 33 containing woven fabric, which reinforces the covering material 20. Furthermore, by providing a synthetic leather layer 31 containing polyvinyl chloride resin as the outermost layer, the texture of the covering material 20 can be improved. Furthermore, since the reinforcing layer 33 is bonded to the synthetic leather layer 31, the synthetic leather layer 31 is reinforced and wrinkles in the synthetic leather layer 31 can be prevented.

The above-described embodiments will be explained in more detail below using examples and comparative examples, but the sewn products and skin-integrated foam molded products of the present disclosure are not limited to the following examples.

1. Structure of the sewn products and skin-integrated foam molded products of Examples and Comparative Examples In Example 1 and Comparative Examples 1 and 2, sewn products and headrests (skin-integrated foam molded products) were obtained using the same manufacturing method as in the first embodiment. Each sewn product was made by sewing together multiple skin materials 20 with a four-layer structure similar to that of the first embodiment. Example 1 and Comparative Examples 1 and 2 differed only in the sewing thread used to sew the skin materials 20 together.

Example 1
The sewing thread used was a polyester resin twisted thread (thread body) coated with a fluororesin (water-repellent coating). Specifically, the sewing thread used was "#8 Col BWRN" manufactured by Toyobo Co., Ltd.

<Comparative Example 1>
The sewing thread used was the same as the thread body of the sewing thread 40 in Example 1. That is, the sewing thread in Comparative Example 1 was made of polyester resin and was not water-repellent coated.

<Comparative Example 2>
The sewing thread used was the fluffed version of the sewing thread of Comparative Example 1. This fluffed thread was the same as the sewing thread of Comparative Example 1 except that it was fluffed, and was made of polyester resin and not water-repellent coated.

2. Evaluation Method For the sewn headrest products of the examples and the comparative examples, protrusions 32T (see FIG. 4 ) where the adhesive of the adhesive layer 32 protruded from the seams 21 were visually checked, and the number of visible protrusions 32T was compared.

3. Evaluation Results Example 1, which used a sewing thread 40 with a water-repellent coating, had fewer adhesive protrusions 32T and a better appearance than Comparative Example 1, which used a sewing thread without a water-repellent coating. This is thought to be because the water-repellent properties of the sewing thread 40 made it difficult for the adhesive layer 32 of the upholstery material 20 to adhere to the sewing thread 40 when the sewing thread 40 penetrated the upholstery material 20 during sewing, making it less likely to be pulled out of the seam 21. Comparative Example 2, which used a fluffy thread as the sewing thread, had an even greater number of adhesive protrusions 32T and a worse appearance than Comparative Example 1. This is thought to be because a fluffy thread is more likely to get caught on the adhesive layer 32 or experience greater frictional resistance when penetrating the upholstery material 20 during sewing. These results suggest that protrusion of the inner layer of the upholstery material 20 from the seam 21 can be prevented by using a sewing thread that has been treated with a surface treatment to improve slipperiness, or a thread made of a fiber with good slipperiness, in addition to a water-repellent coating.

Other Embodiments
(1) The skin-integrated foam-molded product in which the core portion 92 is foam-molded within the sewn product 10 and integrated with the sewn product 10 is not limited to a headrest for a vehicle (e.g., a car), but may also be, for example, an armrest for a vehicle (e.g., a car).

(2) The sewn product 10 may be placed over the core portion 92 after the core portion 92 has been formed. In this case, the core portion 92 may be made of foam, or may be made of a resin other than foam, or may be made of metal or wood.

(3) The sewn product 10 is not limited to being placed inside a vehicle (e.g., inside a car), but may also be placed outside a vehicle (e.g., outside a car). Furthermore, the sewn product 10 does not have to be bag-shaped, and may be, for example, an interior cover for a console box, dashboard, glove box, or door of a vehicle. Furthermore, the sewn product 10 may also be, for example, a cover that forms the surface of furniture used indoors, such as a sofa or chair.

(4) The covering material 20 need only have a laminated structure including the adhesive layer 32, and is not limited to the structure of the first embodiment. The laminated structure of the covering material 20 may be, for example, a two-layer structure (e.g., a structure consisting of the synthetic leather layer 31 and the adhesive layer 32), a three-layer structure (e.g., a structure in which the reinforcing layer 33 or the back layer 34 is removed from the covering material 20 of the first embodiment), or a laminated structure of five or more layers. For example, the covering material 20 may be constructed by providing a front layer of genuine leather or fabric instead of the synthetic leather layer 31, and bonding this front layer to a back layer made of, for example, fiber, with an adhesive layer. The covering material 20 may also have a laminated structure that does not include the adhesive layer 32. Even in this case, the water-repellent properties of the sewing thread 40 prevent the inner layer of the laminated covering material 20 (the back layer in the case of a two-layer structure) from being pulled out by the sewing thread 40 and protruding from the seam 21.

(5) In the first embodiment described above, the surfaces of the covering materials 20 that overlap at the stitching portion are the front side surfaces 20A of the covering materials 20, but they may be the back side surfaces opposite the front side surfaces 20A, or the front side surfaces 20A and the back side surfaces.

Note that while the present specification and drawings disclose specific examples of technology included within the scope of the claims, the technology described in the claims is not limited to these specific examples and includes various modifications and variations of the specific examples, as well as parts of the specific examples taken independently.

REFERENCE SIGNS LIST 10 sewn product 20 covering material 21 seam 31 synthetic leather layer 32 adhesive layer 33 reinforcing layer 40 sewing thread 91 headrest

Claims (6)

A sewn product formed by sewing together a plurality of surface materials having a laminated structure including an adhesive layer,
the sewing thread that sews the skin materials together is water-repellent;
The skin material has a synthetic leather layer as the outermost layer . A sewn product formed by sewing together a plurality of surface materials having a laminated structure including an adhesive layer,
the sewing thread that sews the skin materials together is water-repellent;
the adhesive layer contains a component derived from rubber latex,
The sewing thread is coated with a fluororesin. A sewn product formed by sewing together a plurality of surface materials having a laminated structure including an adhesive layer,
the sewing thread that sews the skin materials together is water-repellent;
The laminated structure of the skin material includes:
a synthetic leather layer containing a polyvinyl chloride resin;
a reinforcing layer including a woven fabric and laminated to the synthetic leather layer via the adhesive layer. a bag-shaped sewn product formed by sewing together a plurality of skin materials having a laminated structure including an adhesive layer;
a foam body that is foam-molded within the sewn product and is integrated with the sewn product,
The stitching thread that stitches the skin materials together is water-repellent. 5. The skin-integrated foam molded product according to claim 4, which is a headrest. The method for manufacturing a sewn product according to any one of claims 1 to 3,
The method for manufacturing a sewn product comprises sewing the skin materials together with a water-repellent sewing thread to produce a sewn product.