JP7554577B2 - Vehicle cushion pad, its manufacturing method, and foam molded product - Google Patents

Description

The present invention relates to a vehicle cushion pad constituting a seat portion of a vehicle seat, and a method for manufacturing the same.

Cushion pads constituting the seating portion of vehicle seats such as automobiles have traditionally been made of soft polyurethane foam molded bodies to provide comfortable cushioning. However, in recent years, in order to improve fuel efficiency, there has been a trend toward reducing weight by replacing part of the soft polyurethane foam molded bodies with first foam molded bodies made of hard foam such as bead foam molded bodies.
The manufacturing process is performed by using a foam molding mold 7 having a cavity C for the cushion pad, which is upside down when the mold is closed compared to when the mold is installed on the vehicle (FIG. 15). After the first foam molded body 2 is set in the upper mold 9, foaming raw material g is injected into the lower mold 8, but it is difficult to release the excess gas generated during the foam molding of the soft polyurethane foam molded body to the outside of the mold. This is because the first foam molded body 2 occupies the upper side of the cavity when the mold is closed, and the structure is prone to underfill defects in the product. Therefore, several inventions have been proposed to deal with underfill defects (for example, Patent Documents 1 and 2).

JP 2017-206077 A JP 2019-187712 A

In Patent Documents 1 and 2, a through hole is provided on the underside of a first foamed molded body that penetrates to the upper side, and a recess is further provided on the upper surface and an opening of the through hole is provided in the bottom area of the recess, making it easier for excess gas to flow toward the through hole and release the excess gas outside the mold.

However, during the foam molding process, it is difficult to collect the excess gas generated in the peripheral area of the upper surface of the first foam molded body in the through holes, and in some cases it is structurally difficult to provide a recess on the upper surface side even in the peripheral area of the upper surface.
For this reason, the present inventors have considered using vertical grooves on the side surface of the first foam molded body to collect the excess gas generated at least in the peripheral region of the upper surface, rather than collecting the excess gas generated in the peripheral region of the upper surface in through holes provided in the central region of the upper surface of the first foam molded body. They have furthered their consideration of using the vertical grooves to allow the excess gas to rise inside the cavity and be released outside the mold from the mold mating surface. Although the bead foam molded body of the first foam molded body and the polyurethane foam molded body have poor adhesion, a part of the polyurethane foam molded body enters the vertical grooves during molding, which is also useful for preventing lateral displacement and is preferable (JP Patent Publication No. 2017-202076).
However, when the vertical grooves 23 are provided on the side walls, voids VD may occur in the vertical grooves 23 as shown in FIG. 15. Recently, the thickness of the side surface layer of the soft polyurethane second foamed molded body 3 has been thinned toward the back side of the cushion pad in order to reduce weight, which has a large effect. In the foaming process, the foaming raw material g rises up the lower mold cavity side wall 812 as shown by the arrow in FIG. 15 (A), reaches the upper mold cavity surface 91 first, and blocks the mold mating surfaces 89, 99, and voids VD are generated in the vertical grooves 23 as shown in FIG. 15 (B). When the surface of the side surface layer 32 is pressed from the outside, only the parts with voids VD are easily dented, resulting in defective products and reduced yields. Furthermore, since the voids VD are inside, they cannot be seen visually, which is troublesome.

The present invention aims to solve the above problems and provide a vehicle cushion pad and a manufacturing method thereof that prevent problems in the product even if gas remains in the longitudinal grooves and voids are formed, stabilizes product quality, and improves yield.

In order to achieve the above object, the gist of the invention described in claim 1 is a vehicle cushion pad formed by covering and laminating a block-shaped first foam molded body as a lower layer with a second foam molded body as a surface layer, the vehicle cushion pad comprising: a plurality of vertical grooves formed in the circumferential direction of the side surface of the first foam molded body; and a tape-like material attached to the side surface beside the groove openings, covering all or part of each of the groove openings related to the plurality of vertical grooves, the second foam molded body covering the tape-like material and laminated to the side surface of the first foam molded body. The vehicle cushion pad according to claim 2 is the vehicle cushion pad according to claim 1, characterized in that the tape-like material is attached to the side surface beside each of the groove openings related to the vertical grooves appearing on the side surface, covering the lower surface region of the first foam molded body. The vehicle cushion pad according to the invention of claim 3 is the vehicle cushion pad according to claim 2, characterized in that one of the tape-like objects closes the lower surface region of the first foamed molded body among the groove openings, and another tape-like object closes the upper region of each groove opening above the lower surface region of the first foamed molded body through a gap between the tape-like object and the tape-like object and is affixed to the side surface. The vehicle cushion pad according to the invention of claim 4 is the vehicle cushion pad according to claims 1 to 3, characterized in that the tape-like object is an adhesive-attached porous tape piece having an adhesive applied to the surface side facing the first foamed molded body. The vehicle cushion pad according to claim 5 is the vehicle cushion pad according to claim 4, characterized in that the porous tape piece is a nonwoven fabric piece. The vehicle cushion pad according to claim 6 is the vehicle cushion pad according to claims 1 to 3, characterized in that the tape-like object comprises an adhesive applied to the side surface beside the groove opening, and a tape piece that closes the groove opening and is affixed to the side surface beside the groove opening by covering the adhesive. The vehicle cushion pad of the invention of claim 7 is characterized in that, in any one of claims 1 to 6, the vertical groove is formed from a side point below the upper end portion of the side of the first foamed molding to the lower end of the side.
The gist of the invention described in claim 8 is a method for manufacturing a vehicle cushion pad by placing an underside of a block-shaped first foam molded body against an upper cavity surface of a foam molding mold and setting the first foam molded body, then injecting foaming raw material onto the lower cavity surface and closing the mold, and then foam molding a surface layer second foam molded body that covers and laminates the first foam molded body so that its underside is exposed, the method comprising using the first foam molded body having a plurality of vertical grooves formed in the circumferential direction of its side surface, closing all or part of the groove openings of the plurality of vertical grooves with a tape-like material and affixing the tape-like material to the side surface beside the groove openings, setting the first foam molded body in the foam molding mold, and then foam molding the second foam molded body that covers the tape-like material and is laminated on the side surface of the first foam molded body. The method for manufacturing a cushion pad for a vehicle according to the invention of claim 9 is characterized in that the tape-like material is attached to the side surface beside each of the groove openings of the vertical grooves appearing on the side surface by closing the lower surface area of the first foamed molded body. The method for manufacturing a cushion pad for a vehicle according to the invention of claim 10 is characterized in that the tape-like material is an adhesive-attached porous tape piece having an adhesive applied to the side surface facing the first foamed molded body.

The vehicle cushion pad and its manufacturing method of the present invention can prevent problems caused by voids even if they occur in the longitudinal grooves of the second foam molded body, and are highly effective in maintaining product quality and improving yield.

FIG. 1 is a perspective view of a cushion pad according to one embodiment of the cushion pad and the manufacturing method thereof of the present invention. FIG. 2 is an exploded perspective view of a first foamed molded body and a tape-like material. FIG. 2 is a perspective view of a first foamed molded body with a tape-shaped material. FIG. 4 is a perspective view of a first foamed molded article with a tape-like material according to another embodiment, which is an alternative to that shown in FIG. 3 . FIG. 4 is a perspective view of a first foamed molded body with a tape-like material according to another embodiment of the present invention, which is an alternative to that shown in FIG. 3 . FIG. 2 is a partial cross-sectional view of the cushion pad of FIG. 1 covered with a skin. FIG. 7 is a partial cross-sectional view of the cushion pad in FIG. 6 before the cover is placed thereon. FIG. 13 is an explanatory cross-sectional view showing how the first foamed molded body with the tape-like material is set in the upper mold and foaming raw material is injected. 4 is an explanatory cross-sectional view showing the process of closing the mold and progressing the foam molding. FIG. FIG. 10 is a partially enlarged cross-sectional view of FIG. 4 is a cross-sectional view of the second foam molded body after foam molding is completed. FIG. FIG. 12 is an alternative view to FIG. 11 . FIG. 3 is an alternative view to FIG. 2 . FIG. 7 is an explanatory cross-sectional view for comparison with FIG. 6 . FIG. 1 is an explanatory cross-sectional view of a conventional technique.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle cushion pad (hereinafter, simply referred to as a "cushion pad") according to the present invention and a method for manufacturing the same will be described in detail below. 1 to 14 show one embodiment of the cushion pad and its manufacturing method of the present invention, in which FIG. 1 is a perspective view of the cushion pad, FIG. 2 is an exploded perspective view of the first foam molded body and the tape-like material of FIG. 1, FIG. 3 is a perspective view of the first foam molded body with the tape-like material, FIG. 4 is a perspective view of the first foam molded body with the tape-like material of another embodiment, FIG. 5 is a perspective view of the first foam molded body with the tape-like material of another embodiment, FIG. 6 is a cross-sectional view of covering the cushion pad of FIG. 1 with a skin, FIG. 7 is a cross-sectional view of the cushion pad, FIG. 8 is an explanatory cross-sectional view of setting the first foam molded body in the upper mold and injecting the foaming raw material, FIG. 9 is an explanatory cross-sectional view of the mold closing and the foam molding proceeding, FIG. 10 is a partial cross-sectional view of FIG. 9, FIG. 11 is a cross-sectional view of the second foam molded body after foam molding is completed, FIG. 12 is a view of another embodiment replacing FIG. 11, FIG. 13 is a view of another embodiment replacing FIG. 2, and FIG. 14 is an explanatory cross-sectional view for comparison with FIG. 6. For ease of understanding, each drawing is simplified to emphasize the essential parts of the invention.

(1) Vehicle Cushion Pad The vehicle cushion pad 1 is a seat pad for an automobile or the like that supports the lower body of a seated occupant. This embodiment is applied to a cushion pad 1 for a rear seat as shown in Fig. 1. If the cushion pad 1 is covered with a skin 5 to form a seat cushion, a rear seat with an auxiliary seat added to the center in the vehicle width direction is formed by a seat back in which the skin 5 is covered on a known back pad.
The cushion pad 1 includes a first foamed molded body 2, vertical grooves 23, a tape-like material 4, and a second foamed molded body 3. In Fig. 1, the diagonally lower left direction on the paper surface corresponds to the front of the vehicle.

The first foamed molded body 2 is a foamed molded body of hard foam molded into a block shape with a size as shown in FIG. 2 occupying the lower half of the cushion pad 1. It is a foamed molded body of bead-method expanded polypropylene, bead-method expanded polystyrene, etc. For example, when it is made into a molded body of bead-method expanded polypropylene (this embodiment), the inside becomes a highly expanded layer with an arbitrary expansion ratio, and the surface becomes a hardened film layer. When it is made into a non-breathable foamed molded body with a surface film, the apparent density after expansion becomes smaller than that of the second foamed molded body 3, and the first foamed molded body 2 is very light for its size.
The block-like first foamed molded body 2 is disposed on the lower surface side of the cushion pad 1 to reduce the weight of the vehicle, and the lower surface 2b is exposed and becomes the lower layer of the cushion pad 1. In the present invention, the "lower surface" refers to the "lower surface" hidden by the paper surface of the cushion pad 1 in Fig. 1 in the state of being attached to the vehicle, and the "upper surface" refers to the upper surface that comes into contact with the buttocks of a seated occupant. The "lower surface" in the seat pad of the present invention is the same, and in the cushion pad 1 in Fig. 11 which is foamed and molded upside down from the state of being attached to the vehicle, it refers to the upper direction on the paper surface, and "upper" refers to the lower direction on the paper surface.

The vertical grooves 23 are recessed grooves with a U-shaped cross section formed in a plurality of portions on the side surface 22 of the first foam molded body 2. In the foam molding of the first foam molded body 2, a plurality of vertical grooves 23 running in the vertical direction at a predetermined interval in the circumferential direction of the side surface 22 are molded together. In this embodiment, three vertical grooves 23 are provided that penetrate from the upper surface 2a to the lower surface 2b of the first foam molded body 2, exposing the groove openings 230 on the vehicle front side surface 22 of both window side seat parts 11 except the auxiliary seat part. The openings of the upper ends 233 of the vertical grooves appear on the upper surface 2a of the first foam molded body, and the openings of the lower ends of the vertical grooves appear on the lower surface 2b (FIG. 2). In reality, more vertical grooves 23 are provided than this, and the dimension of the groove depth of the vertical grooves 23 is set larger than the groove width. The upper surface 2a around the openings of the upper ends 233 of the vertical grooves is slightly inclined toward the openings. In the foam molding of the second foam molded body 3 described later, excess foaming gas is easily allowed to flow in.
Incidentally, in a normal cushion pad 1, the thickness t1 of the second foam molded body 3 becomes small near the lower surface 2b of the first foam molded body 2, but the thickness t2 of the second foam molded body 3 is sufficiently secured at the side surface 22 near the upper surface 2a of the first foam molded body (FIG. 7). Therefore, in the side surface portion near the upper surface a, the excess foaming gas generated during the foam molding of the second foam molded body 3 can pass through smoothly. In such a case, as shown in FIG. 12, the upper end portion 222a of the side surface 22 of the first foam molded body 2 does not have a vertical groove 23, and the vertical groove 23 can be formed from a point on the side surface below the upper end portion 222a to the lower end 2211 of the side surface.
A groove opening 230 is exposed at the location of the vertical groove 23 on the side surface 22 of the first foamed molded body 2 , but the groove opening 230 is closed by the tape-like material 4 .

The tape-like material 4 is a strip-shaped sheet piece 41 with adhesive 42 that covers all or part of each groove opening 230 of the multiple vertical grooves 23 and is attached with adhesive 42 to the first foamed molded body side surface 22 beside the groove opening 230 (FIGS. 2 and 3). The adhesive 42 in the present invention includes a pressure-sensitive adhesive.
Specifically, the tape-like material 4 comprises an adhesive 42 that can be adhered to the side surface 22 of the first foam molded body, and a belt-like sheet piece 41 to which the adhesive 42 is applied. It is more preferable that the tape-like material 4 has the adhesive 42 only at the portion facing the side surface 22, and the portion that directly closes the groove opening 230 is the belt-like sheet piece 41 without the adhesive 42. This is because, during foam molding of the second foam molded body 3, the foaming raw material g and excess foaming gas can smoothly pass through the belt-like sheet piece 41.

The tape-like material 4 may be a material in which the belt-like sheet piece 41 and the adhesive 42 are separated as shown in Fig. 13 and finally bonded to the side surface 22 as a unit. That is, the tape-like material 4 is composed of the adhesive 42 applied to the side surface 22 beside the groove opening 230 and the belt-like sheet piece 41 that is placed over the adhesive 42 to close the groove opening 230 and bonded. In this embodiment, the tape-like material 4 is not separated, but is formed by applying the adhesive 42 to the belt-like sheet piece 41 on the side facing the first foamed molded body 2. The tape-like material 4 may be a material in which one side of a double-sided tape is bonded to the belt-like sheet piece 41. If the belt-like sheet piece 41 is a porous tape piece 41a, it is also useful for integrating the first foamed molded body 2 and the second foamed molded body 3. This is because, during the foam molding of the second foam molding body 3, the foaming raw material g penetrates into the porous tape piece 41a of the tape-like material 4 attached to the first foam molding body 2, and the second foam molding body 3 is integrated with the first foam molding body 2 via the tape-like material 4.

Here, the adhesive 42 applied to the surface of the belt-shaped sheet piece 41 facing the first foam molded body side surface 22 is difficult to adhere to the first foam molded body 2 because the first foam molded body 2 is made of foamed polypropylene with low polarity. Nevertheless, it is possible to adhere to the first foam molded body 2 by using an adhesive for difficult-to-adhere materials or a primer in combination, and the present invention is sufficient as long as the tape-like material 4 is attached to the first foam molded body 2 until the end of foam molding of the second foam molded body 3. For example, the adhesive 42 can be a polyamide-based hot melt adhesive or a two-part acrylic-based spreadable adhesive.

On the other hand, the strip-shaped sheet piece 41 of the tape-like material 4 is preferably a porous tape piece 41a as described above, and specific examples thereof include porous tape pieces made of breathable fabrics such as knitted fabrics and woven fabrics, as well as nonwoven fabrics, felt, slab urethane, etc.
The tape-like material 4 of the porous tape piece 41a with adhesive 42 on the side facing the first foam molding 2 covers the groove opening 230 and is bonded and fixed to the side surface 22 of the first foam molding beside it by the adhesive 42 (FIGS. 2 and 3). In addition, the foaming raw material g penetrates and hardens into the porous tape piece 41a during foam molding of the second foam molding 3, which has the effect of bonding the first foam molding 2 made of foamed polypropylene and the second foam molding 3 made of soft polyurethane, which are originally difficult to bond, via the tape-like material 4. Here, a nonwoven tape piece is used as the porous tape piece 41a. The foaming raw material g penetrates into the three-dimensional network structure of the nonwoven tape piece and hardens, thereby strengthening the integration of the second foam molding 3 and the porous tape piece 41a.

In the cushion pad 1 of this embodiment, of the groove openings 230 relating to the vertical grooves 23 appearing on the side surface 22, the tape-like material 4 as shown in Figures 1 and 6 covers the underside region 221 of the first foam molded body side surface 22, and is attached to the side surface 22 of the first foam molded body 2 beside each groove opening 230. The entire region of the first foam molded body side surface 22 where the vertical grooves 23 are present may be covered with the tape-like material 4 as shown in Figure 5, but the problem of the present invention can be solved even if only the lower half of the underside 2b side of the region of the first foam molded body side surface 22 where the vertical grooves 23 are present is covered with the tape-like material 4.
The voids VD generated in the vertical grooves 23 during foam molding of the second foamed molded body 3 tend to occur in the lower half of the vertical grooves 23 on the side surface 22 close to the lower surface 2b of the second foamed body, as shown in Figure 15 (B) on the lower surface 2b side. Although it is not visible from the outside, it is easily dented when an external force is applied in the direction of the outlined arrow as shown in Figure 7.
Therefore, the tape-like material 4 is attached to the lower half region of the lower surface 2b side of the first foamed molded body so as to cover the groove opening 230 of the vertical groove 23 as shown in Fig. 3. More specifically, both ends of the tape-like material 4 that closes the groove opening 230 are attached to both side surfaces 22 adjacent to the groove opening 230. Then, even if an external force is applied in the direction of the outlined arrow in Fig. 7, the tape-like material 4 absorbs the external force in the same way as the other parts of the side surface 22 absorb the force, solving the problem of easy denting.

In addition, the tape-like material 4 closes the lower half of the lower surface 2b side with the first foam molded body side surface 22 having the vertical groove 23, so that the lower edge of the cushion pad 1 is circumferentially aligned and looks good. The cushion pad 1 has its front surface 3a covered with a skin body 51 as shown in Fig. 14(A), and a fastener 52 attached to an end of the skin 5 is inserted into and fastened to a groove 29 of the first foam molded body 2 provided along the periphery of the back surface of the cushion pad. When the fastener 52 is fastened to the groove 29, the skin body 51 covers the cushion pad 1 so as to be taut without slack, so that the soft second foam molded body 3 near the lower end of the hard first foam molded body 2 is compressed by the skin 5 being stretched as shown in Fig. 14(A), and the corners 321 are slightly crushed and rounded.
On the other hand, where the vertical grooves 23 are present, the soft second foam molded body 3 is filled from the side surface 22 of the first foam molded body to the groove bottom 231 of the vertical grooves 23. When the skin 5 covers the corners 322 of the second foam molded body 3 near the lower end 2211 where the vertical grooves 23 of the rigid first foam molded body 2 are present, the corners 322 fall significantly from the dashed line position as shown in Figure 14 (b) . When the seat pad is formed, the lower edge of the seat pad will have unevenness in the circumferential direction at the points 322 where the vertical grooves 23 are present and the points 321 where they are not, resulting in a poor appearance.
However, if the tape-like material 4 covers the side surface 22 on the lower surface 2b side of each groove opening 230, including the lower edge portion of the first foamed molded body 2, such a problem does not occur. Even if the second foamed molded body 3 is filled up to the groove bottom 231 as shown in Figure 6, the tape-like material 4 covers and blocks the vertical grooves 23, preventing the second foamed molded body 3 from falling into the vertical groove filling portion 33 in the vertical groove 23. Even if the skin 5 is stretched, as shown in Figure 6, the corners 322 are only slightly crushed and rounded, and the situation is the same as Figure 14(A) where there is no vertical groove 23, and the circumferential wavy unevenness at the lower edge portion of the seat pad disappears.

4, it is more preferable that the tape-like material 4 not only closes the side surface 22 on the lower surface 2b side of the first foam molded body among the groove openings 230, but also closes the upper region 222 of the first foam molded body side surface 22 above the lower surface region 221 through the tape-like material 4 and the gap ε of the tape-like material 4, and the cushion pad 1 is attached to the side surface 22. It is even more preferable that the other tape-like material 4 closes the side surface 22 of the upper region 222 including the side surface upper end 2221 (FIG. 4). The upper surface layer 31 of the second foam molded body 3 is laminated on the corner between the first foam molded body upper surface 2a and the side surface upper end 2221 on the vehicle front side, but the corner is still a place where the back of the knee of a seated occupant hits, and the depression of the vertical groove upper end 233 may sometimes cause discomfort. This sense of incongruity can be eliminated by using another tape-like material 4 to close the upper end region of the groove opening 230 that creates a recess and attaching both ends to the side surface 22.

The second foam molded body 3 is a surface layer of a foam molded body that is laminated to cover the first foam molded body 2 that is the underlying layer, and is composed of a soft polyurethane foam molded body in this example.
The lower surface 2b of the first foam molded body 2 is exposed, and the remaining upper surface 2a and side surface 22 of the first foam molded body 2 are covered with the second foam molded body 3. The side surface 22 of the first foam molded body 2 covering the tape-like material 4 is laminated to the side surface layer portion 32 of the second foam molded body 3. The tape-like material 4 is attached to the first foam molded body 2 that has been molded in advance. The first foam molded body 2 with the tape-like material 4 is then used as an insert product, with the upper surface layer portion 31 laminated on the upper surface 2a, and the side surface layer portion 32 laminated by foam molding on the side surface 22 including the tape-like material 4, to form the second foam molded body 3 whose back surface 3b abuts against the first foam molded body 2.
At the location of the vertical groove 23, during foam molding of the second foamed molded body 3, the foaming raw material g penetrates into the vertical groove 23 as well as the upper surface layer portion 31 and the side surface layer portion 32, and foam molding is performed to form a vertical groove filling portion 33. The vertical groove filling portion 33 protrudes from the side surface layer portion 32 to fill the vertical groove 23 and abut against the groove bottom 231 and the groove wall 232. Then, at the location of the tape-like material 4, the tape-like material 4 is interposed at the boundary between the vertical groove filling portion 33 and the side surface layer portion 32, forming the desired cushion pad 1.
Such a cushion pad 1 is manufactured as follows.

(2) Manufacturing Method of Vehicle Cushion Pad The cushion pad 1 is manufactured, for example, by the following manufacturing method. Using a foam molding die 7, the second foam molded body 3 of soft polyurethane, which will be the surface layer on the side that comes into contact with the occupant, is foam molded, and the first foam molded body 2 and the tape-like material 4 are embedded and integrated by this foam molding to manufacture a vehicle cushion pad. Prior to manufacture, the first foam molded body 2 and tape-like material 4 described in (1) and the foam molding die 7 are prepared.

The first foamed molded body 2 is a foamed molded body of a rigid foam having a plurality of vertical grooves 23 formed in the circumferential direction of the side surface 22. The tape-like material 4 is a strip-shaped sheet piece 41 having an adhesive 42 attached to one surface thereof.

The foam molding die 7 is a split die as shown in Fig. 8, and a lower die 8 and an upper die 9 are connected by a hinge (not shown) so as to be able to open and close. When the die is closed as shown in Fig. 9, a cavity C for the cushion pad 1 is formed by a lower die cavity surface 81 which is generally recessed in a bowl shape to form a contact surface for a seated occupant, and an upper die cavity surface 91 which matches the generally flat lower surface 2b of the first foam molding body 2. The cavity C represents the cross-sectional shape of the cushion pad 1 in the vehicle front-rear direction passing through the vertical groove 23 in Fig. 1. The foam molding die 7 in Figs. 8 to 11 molds the cushion pad 1 in Fig. 1 upside down.

Using the first foamed molded body 2, the tape-like material 4, and the foam molding die 7, the cushion pad 1 is manufactured, for example, as follows.
First, a first foam molded body 2 having a plurality of vertical grooves 23 formed on a side surface 22 is used, all or part of each groove opening 230 of the plurality of vertical grooves 23 is closed with a tape-like material 4, and the tape-like material 4 is attached to the side surface 22 beside the groove opening 230. Then, the lower surface 2b side of the first foam molded body 2 with the tape-like material 4 is placed against the upper mold cavity surface 91 of the foam molding mold 7, and the first foam molded body 2 is set in the upper mold 9 (FIG. 8). Alternatively, after the lower surface 2b side of the first foam molded body 2 is placed against the upper mold cavity surface 91 of the foam molding mold 7 and the first foam molded body 2 is set in the upper mold 9, all or part of each groove opening 230 is closed with the tape-like material 4, and the tape-like material 4 is attached to the side surface 22 beside the groove opening 230.
After the first foamed molded body 2 with the tape-like material 4, in which all or part of each groove opening 230 is blocked with the tape-like material 4, is set into the foam molding mold 7, a predetermined amount of foaming raw material g for the second foamed molded body 3 is injected onto the lower mold cavity surface 81 using an injection nozzle NL or the like.

In this embodiment, a porous tape piece 41a with adhesive 42 applied to the side facing the first foam molding 2 is used as the tape-like material 4. The tape-like material 4 closes each groove opening 230 of the vertical grooves 23 appearing on the side surface 22 of the first foam molding, in the lower surface region 221 of the side surface 22 of the first foam molding, and both ends of the closed porous tape piece 41a are attached to the side surface 22 beside each groove opening 230 (FIGS. 3 and 8). After the first foam molding 2 with the tape-like material 4 is set in the foam molding mold 7, the foaming raw material g is injected onto the lower mold cavity surface 81.

Next, the upper mold 9 is operated to close the mold (FIG. 9). By closing the upper mold 9 and the lower mold 8, a cavity C for the cushion pad 1 is formed in which the first foamed molded body 2 with the tape-like material 4 is insert-set. In this embodiment, the mold is closed after the foaming raw material g is injected, but the foaming raw material g can also be injected after the mold is closed.

After the mold is closed, the process proceeds to foam molding of the second foam molded body 3. The second foam molded body 3 is foam molded and is made of a soft polyurethane foam molded body having a contact surface portion for a seated occupant on the design surface side. The mold closed state shown in FIG. 9 is maintained for a predetermined time to form an upper surface layer portion 31 having a contact surface portion, and the foam raw material g is impregnated and hardened in the tape-like material 4, and a side surface layer portion 32 is foam molded, the back surface 3b side of which contacts the side surface 22 of the first foam molded body 2 directly or via the tape-like material 4. Furthermore, a part of the foam raw material g forming the side surface layer portion 32 enters the vertical groove 23 and foam molds the vertical groove filling portion 33 that fills the vertical groove 23. In this way, the second foam molded body 3 is formed in which the back surface 3b side of the second foam molded body 3 is joined to the upper surface 2a and side surface 22 of the first foam molded body.

In the foam molding of the second foam molded body 3, the foaming raw material g rises in the cavity C under the closed mold. Most of the air and excess foaming gas present in the cavity C passes through a through hole (not shown) provided in the center of the upper surface 2a of the first foam molded body to the lower surface 2b. Excess foaming gas present around the upper surface 2a also rises through the vertical groove 23 and is released outside the mold through the mold mating surfaces 89, 99 and the escape groove (not shown).
Meanwhile, the liquid foaming raw material g foams and rises, filling the cavity C, and foams and molds the second foamed molded body 3 having an upper surface layer portion 31, a side surface layer portion 32, and further a vertical groove filling portion 33. At the same time, during this foaming molding process, a part of the foaming raw material g penetrates into the porous tape piece 41a of the tape-like material 4. The foaming raw material g that penetrates into the fine pores in the porous tape piece 41a impregnates and hardens the tape-like material 4. After a predetermined time has passed, the desired cushion pad 1 as shown in FIG. 11 is obtained by foaming and molding the second foamed molded body 3 having the upper surface layer portion 31, the vertical groove filling portion 33, and the side surface layer portion 32 that covers the tape-like material 4 and is laminated on the side surface 22 of the first foamed molded body 2.

Here, the foaming raw material g tends to rise up along the lower mold cavity side wall 812 rather than up along the first foam molded body side surface 22. The foaming raw material g that reaches the mold mating surfaces 89, 99 foams and rises quickly as shown in Fig. 9, and the foaming raw material g that reaches the upper mold 9 first may enter the vertical groove 23 as shown in Fig. 10 and block the path of the excess foaming gas rising in the vertical groove 23. The excess foaming gas is left behind in the cavity C, and a void VD as shown in Fig. 7 is formed in the cushion pad 1 after foam molding has been completed.
However, even if such voids VD are formed, the present invention prevents the influence of the voids VD by closing the groove opening 230 of the vertical groove 23 where the voids VD are likely to be formed with the tape-like material 4. The groove opening 230 is covered with the tape-like material 4, both ends of which are attached to the side surface 22 around the groove opening 230, and the second foamed molded body 3 is covered and foamed to produce the desired cushion pad 1 which solves the problem of voids VD.

Fig. 12 shows another embodiment instead of Fig. 11. The desired cushion pad 1 is produced using a first foamed molded body 2 in which the vertical groove 23 is not provided in the upper end portion 222a of the side surface 22 of the first foamed molded body, but in which the vertical groove 23 is formed from a side surface point below the upper end portion 222a to the lower end of the side surface 22.
The reference numeral 12 denotes a connection portion with the backrest. The other configurations are the same as those of the cushion pad (1), and therefore the description thereof will be omitted. The same reference numerals as those in (1) denote the same or corresponding parts.

(3) Effects According to the vehicle cushion pad and its manufacturing method thus constructed, a part of the conventional soft polyurethane foam molded body is replaced with the first foam molded body 2 made of light rigid foam, so that weight reduction can be promoted. At the same time, the upper surface layer 31 and the side surface layer 32 of the second foam molded body 3 made of soft polyurethane cover the first foam molded body 2 to form the surface layer, so that the appearance is the same as the conventional one. The upper surface layer 31 with a large thickness t3 is provided under the buttocks of the seated occupant, so that comfortable cushioning properties are maintained. In addition, during foam molding of the second foam molded body 3, excess foaming gas generated around the upper surface 2a of the first foam molded body can pass through the vertical groove 23 and be released outside the mold through the mold mating surfaces 89, 99.

In the foam molding of the second foam molded body 3, even if the foaming raw material g reaches the mold mating surfaces 89, 99 first along the cavity side wall 812 of the lower mold 8 and traps the excess foaming gas from the vertical groove 23, causing a void VD, no trouble due to the void VD occurs.
As in claims 1 and 8, when a tape-like material 4 is provided which covers all or part of each groove opening 230 of a plurality of formed vertical grooves 23 and is attached to the side surface 22 of the first foam molded body beside the groove opening 230, and the second foam molded body 3 is laminated to the side surface 22 of the first foam molded body while covering the tape-like material 4, the groove opening 230 of the vertical groove 23, where voids VD are likely to occur, can be sealed by covering it with the tape-like material 4, so that the voids VD present below the groove opening 230 do not affect the product quality. The voids VD are likely to occur at the groove bottom 231 of the vertical groove 23, and if there are voids VD, this part is easily dented by external force (B in FIG. 15), a problem that has been seen up until now, is eliminated by the tape-like material 4 (FIG. 7). The tape-like material 4 is taut and covers the vertical groove mouth 230 with the void VD, and is attached to both side surfaces 22 beside the groove mouth 230, thereby maintaining substantially the same rigidity as the side surfaces 22 around the groove mouth 230. Therefore, even if an external force is applied as indicated by the white arrow in Fig. 7, the tape-like material 4 blocks the external force from being transmitted to the void VD, and the tape-like material 4 can absorb the external force. Even if gas remains in the vertical groove 23 and a void VD is formed, it does not affect the product. This leads to stable product quality and improved yield.

As in claims 2 and 9, when the tape-like material 4 closes the underside region 221 of the first foam molded body side surface 22 of each groove opening 230 of the vertical groove 23 and is attached to the side surface 22, the amount of tape-like material 4 used can be reduced and product quality can be effectively stabilized even if voids VD are formed in the vertical grooves 23. Since the thickness t1 of the side surface layer portion 32 becomes thinner toward the back surface side of the cushion pad 1 and voids VD are likely to be formed in the vertical grooves 23 in the region on the underside 2b of the first foam molded body, the tape-like material 4 can be attached to the vertical grooves 23 in this region, thereby achieving the above-mentioned effect with less usage of tape-like material 4 and less labor required for attaching the tape-like material 4.
Furthermore, as already mentioned, when the lower end of the tape-like material 4 is aligned with the lower end of the side surface of the first foamed molding 2 to fill the vertical groove 23 in the lower side area 221, the circumferential wavy unevenness in the lower edge portion of the seat pad 1 is also eliminated.

As in claim 3, one of the tape-like materials 4 covers the underside region 221 of the first foamed molded body side surface 22 of each groove opening 230, and another tape-like material 4 covers the upper region 222 of each groove opening 230 above the underside region 221 of the first foamed molded body side surface 22 of each groove opening 230 via a gap ε between the tape-like material 4 and the side surface 22, thereby preventing a seated occupant from feeling uncomfortable due to the depression that sometimes occurs at the upper end 233 of the vertical groove compared to other parts.
Although the hard first foamed molded body 2 is covered with a cushioning upper surface layer 31, when sitting down, the occupant may feel a depression at the upper end 233 of the vertical groove of the first foamed molded body 2 through the upper surface layer 31. This problem is solved by closing the groove mouth 230 at this location with another tape-like material 4. As the groove mouth 230 at the upper end region of the vertical groove 23 is sealed with the tape-like material 4, the presence of the vertical groove 23 does not give the occupant an uncomfortable feeling.

As in claims 4 and 10, when the tape-like material 4 is a porous tape piece 41a with adhesive 42 applied to the surface facing the first foamed molded body 2, the foaming raw material g penetrates and hardens into the porous tape piece 41a during foam molding of the second foamed molded body 3, so that the first foamed molded body 2 made of foamed polypropylene and the second foamed molded body 3 made of soft polyurethane, which were previously difficult to bond, can be bonded via the tape-like material 4.
As in claim 5, when the porous tape piece 41a is a nonwoven fabric piece, the foaming raw material g penetrates into the three-dimensional mesh structure of the nonwoven fabric tape piece and hardens, thereby further strengthening the integration between the second foamed molding 3 and the porous tape piece 41a.
As described above, the vehicle cushion pad and the manufacturing method thereof exhibit the above-mentioned various excellent effects and are extremely useful.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention according to the purpose and application. The shapes, sizes, numbers, materials, etc. of the first foamed molded body 2, the second foamed molded body 3, the tape-like material 4, the foam molding die 7, etc. can be appropriately selected according to the application.

1 Cushion pad 2 First foam molded body 2b Lower surface (lower surface of first foam molded body)
22 Side surface (first foamed molded body side surface)
221 Lower surface region 23 Second foam molding 4 Tape-like material 41a Porous tape piece 42 Adhesive 7 Foam molding mold 81 Lower mold cavity surface 91 Upper mold cavity surface C Cavity g Foaming raw material (polyurethane foaming raw material)

Claims (9)

A cushion pad for a vehicle, comprising a block-shaped first foam molded body as a lower layer, and a second foam molded body as a surface layer, the second foam molded body being covered and laminated thereon,
A plurality of vertical grooves formed in the circumferential direction of the side surface of the first foamed molded body;
a tape-like material that covers all or a part of each of the groove openings of the plurality of vertical grooves and is attached to the side surface beside the groove openings,
The tape-like material is attached to the side surface beside each of the groove openings of the vertical grooves that appear on the side surface, by closing a lower surface region of the first foamed molded body,
The vehicle cushion pad is characterized in that the second foam molded body covers the tape-like material and is laminated on a side surface of the first foam molded body. 2. The vehicle cushion pad according to claim 1, wherein one of the tape-shaped materials covers the lower surface area of the first foamed molded body among the groove openings, and another tape-shaped material covers the upper area of the groove openings above the lower surface area of the first foamed molded body through a gap between the tape-shaped material and the other tape-shaped material and is attached to the side surface. 3. The vehicle cushion pad according to claim 1, wherein an adhesive is applied between the side surface beside the groove opening and the tape-like material. 4. The vehicle cushion pad according to claim 1, wherein the tape-like material is a piece of nonwoven fabric. The tape-like material is porous,
The vehicle cushion pad according to claim 1 , wherein the second foamed molded body penetrates into the tape-like material. 6. The vehicle cushion pad according to claim 1, wherein the longitudinal groove is formed from a point on the side surface of the first foamed molded body, excluding an upper end portion thereof, to a lower end portion of the side surface. 6. The vehicle cushion pad according to claim 1, wherein the vertical groove is formed to reach an upper end of a side surface of the first foamed molded body, and an upper surface of the first foamed molded body around an opening at the upper end of the vertical groove is inclined toward the opening. A method for manufacturing a cushion pad for a vehicle, comprising the steps of: placing a bottom surface side of a block-shaped first foam molded body against an upper cavity surface of a foam molding mold to set the first foam molded body; injecting foaming raw material onto the lower cavity surface of the lower mold and closing the mold; and foam molding a surface layer second foam molded body which is laminated and covers the first foam molded body so that its bottom surface is exposed,
The first foamed molded body has a plurality of vertical grooves formed in the circumferential direction of the side surface,
all or a part of each groove opening of the plurality of vertical grooves is closed with a tape-like material, the tape-like material is attached to the side surface beside the groove opening, and the first foamed molded body is set in a foam molding die, and then the second foamed molded body is foam-molded to cover the tape-like material and be laminated on the side surface of the first foamed molded body ;
A method for manufacturing a cushion pad for a vehicle, characterized in that the tape-like material is attached to the side surface beside each of the groove openings of the vertical grooves appearing on the side surface by blocking the lower surface area of the first foamed molded body . A foam molded body constituting a lower layer of a vehicle cushion pad,
A plurality of vertical grooves formed in the circumferential direction of the side surface;
a tape-like material that covers all or a part of each of the groove openings of the plurality of vertical grooves and is attached to the side surface beside the groove openings,
A foamed molded body characterized in that the tape-like material covers the lower surface area of each groove opening of the vertical grooves appearing on the side surface, and is attached to the side surface beside each groove opening.

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