JPH0675884B2 - Method for manufacturing different hardness cushion body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a different hardness cushion body having a soft portion and a hard portion and covered with an epidermis.

The different hardness cushion body obtained by the present invention is a seat,
It can be used as a headrest.

[Prior Art] For example, a headrest of an automobile is required to have a good holding property for supporting the head and a good tactile sensation to the head. However, since it is necessary to make it hard in order to satisfy the holding property and soft in order to improve the tactile feel, it is difficult to realize both of these performances with one foam.

Therefore, there is known a different hardness headrest in which the central part of the front part with which the head is in contact is soft and both side parts are hard.
By doing so, both performances described above can be satisfied.

As a method of manufacturing such a different hardness headrest, (1) a method in which a slab foam, a non-woven fabric, or the like is partially disposed in a molding die and integrally molded, and the resin is impregnated to harden the portion ( 2) A method of adhering a soft foam previously cut into a three-dimensional shape to the surface of the foam molded article (3) A method of partially varying the thickness of the backing material formed on the back surface of the skin (4) As disclosed in Japanese Patent Laid-Open No. 63-218317, there is known a method of molding one of a hard foam and a soft foam and then molding the other.

[Problems to be Solved by the Invention] However, the above-described conventional manufacturing method has various problems to be solved as described below.
According to the method (1), it is difficult to position the nonwoven fabric or the like in the mold, and the hardness varies depending on the degree of impregnation of the foamed resin, so that the quality is not stable. In the method (2), the number of steps for cutting into a three-dimensional shape is large, and the number of bonding steps is increased, so that there is a problem in terms of cost. In the method (3), there are cases where the shape is greatly restricted and the work of sewing the outer skin or the work of covering the outer skin becomes difficult. The method (4) requires two molding steps, and the molding cycle time becomes long, so the productivity is low.

Furthermore, since such a method generally seeks to obtain a different hardness headrest by covering the bag-shaped skin body after forming the foamed molded body, in recent years, for the purpose of reducing the number of steps and improving the feel. Such a method cannot be used in the integral foam molding method using sewn skins, which is increasingly used, and even if a device such as a backing material is used on the skin side, a sufficient feel can be obtained. Things were difficult in practice.

The present invention has been made in view of such circumstances,
The object of the invention is to manufacture a cushioning body of different hardness with high productivity and a small number of man-hours, and stable quality.

[Means and Actions for Solving the Problem] In the method for manufacturing a different hardness cushion body according to the present invention for solving the above problems, a peripheral edge portion of a film-shaped partition member is provided on the inner peripheral surface of a skin body formed in a predetermined shape. A first cavity space is fixed by the cover body and the partitioning member, and a second cavity space is formed by the other inner peripheral surface of the skin or the facing mold surface and the partitioning member. First
The foamed resin is foamed, and the partition member is pressed toward the second cavity space by the foaming pressure to form a first foamed body having a convex curved surface, and a composition different from that of the first foamed resin is formed in the second cavity space. The second foamed resin is foamed to form a second foamed body.

In the manufacturing method of the present invention, first, the peripheral portion of the film-shaped partition member is fixed to the inner peripheral surface of the epidermis. As a method for fixing the peripheral portion of the partition member, a method of adhering or a method of sewing to the skin is adopted. When the outer skin body is sewn into a bag shape, it is convenient to integrally sew and fix the partition member at the time of sewing. As a result, the partition member and one of the pair of inner peripheral surfaces of the skin member facing each other form a first cavity space, and the partition member and the other inner peripheral surface form a second cavity space.

As the partition member, a member that does not allow the foamed resin to permeate and is easily deformed by the pressure of foaming can be used. For example, urethane film, vinyl chloride film, polyester film, polyolefin film, etc. are used,
It is preferable to use one having excellent adhesiveness to the foamed resin. For example, when urethane foam is used as the resin foam, a urethane film is particularly preferable.

The skin of the partition member is usually placed in the molding die. In the first cavity space and the second cavity space, the first foamed resin and the second foamed resin having different compositions are used.
The foamed resin is injected and foam-molded to integrally bond with the skin body. At this time, the partition member is pressed toward the second cavity space by the foaming pressure of the first foamed resin. Since the peripheral edge portion of the partition member is fixed to the inner peripheral surface of the skin body, the partition member has a convex curved surface shape in which the central portion swells by pressing and projects toward the second cavity space. Therefore, the first foam obtained in the first cavity space has a shape in which the thickness gradually increases from the peripheral portion toward the central portion. As a result, if the first foam is made softer than the second foam, the apparent hardness changes continuously, and the feel during use becomes excellent.

To do so, for example, the first foamed resin and the second foamed resin are foamed almost simultaneously. Since the pressure of each foamed resin injected into the first cavity space and the second cavity space is uniquely determined by the composition and amount thereof, the partition member can be pressed with a predetermined pressure difference set in advance. . It is hardly affected by a slight difference in the foaming start time. It is also possible to form the first foam molded body first and then foam the second foam resin. However, in this case, since the forming step is required twice, the molding cycle becomes long, which is not preferable.

The partition member must be fixed so that it can be easily deformed by the pressure during foaming as described above. For example, as the partition member, it is preferable to use an expansive film that expands in response to the magnitude of the stress when the stress acts. If the expandable film is used, the expandable film can be easily expanded by a predetermined amount to obtain the first foam having a predetermined shape. If the partition member is difficult to expand, the peripheral portion may be fixed in a loosened state. The slack is eliminated by the foaming pressure, and a first foam having a convex curved surface protruding according to the amount of the slack is obtained.

In addition, it is preferable to perform a degassing step in order to prevent gas accumulation during foaming. Since the partition member is pressed from the first cavity space toward the second cavity space, it is particularly desirable to perform degassing in the first cavity space. If a partition member having air permeability is used, it is convenient because the gas accumulation can be prevented without degassing.

The first foam and the second foam are partitioned by the partition member and are not in contact with each other. Therefore, the types of the first foamed resin and the second foamed resin can be freely selected regardless of their compatibility, adhesiveness, or the like. Although the hardness can be freely set, in the case of a seat or a headrest, it is desirable that the first foam be softer than the second foam.

[Effects of the Invention] Therefore, according to the method for manufacturing a cushioning body of different hardness of the present invention, the first foamed resin and the second foamed resin can be foamed almost at the same time. The cycle time is almost the same as when molding from foamed resin, and the cycle time does not increase. Further, since the degree of deformation of the partition member is uniquely determined by the composition and injection amount of the first foamed resin and the second foamed resin, the first foamed body and the second foamed body can be formed with good shape reproducibility. Further, the same mold as the conventional mold can be used, and an increase in cost required for the mold can be prevented.

The obtained first foam has a thin peripheral portion and a thicker shape toward the central portion. Therefore, if the hardness of the first foam is softer than that of the second foam, the periphery of the first foam is felt to be hard because the influence of the second foam is great, and the first foam becomes softer toward the central portion. I can feel it,
The apparent change in hardness is continuous and a sudden change in hardness is prevented.

[Examples] Hereinafter, specific examples will be described.

(Example 1) In this example, the present invention is applied to the manufacture of a headrest of an automobile as shown in Fig. 1. This headrest is formed by integrally joining a bag-shaped skin body that is sewn in advance to a foam body made of urethane foam. The headrest 1 has a front surface portion 10 including a central portion 10a that supports the occipital region of the human body and side portions 10b that extend slightly curved to the left and right sides of the central portion 10a and that wrap around the occipital region.
And two stays 11 that are inserted and held in the seat from the bottom surface 11
Is protruding.

FIG. 2 shows a rear view of the epidermis, and FIG. 3 shows an enlarged cross-sectional view of a main part of the epidermis. The skin body 2 is made of a woven fabric 20 and a slab foam 21 joined to the back side of the woven fabric 20 and having a large number of closed cells.
The cloth-like material cut into a predetermined shape is sewn so as to fit the inside surface. The peripheral portion of the expandable urethane foam 3 (thickness 30 μm) is integrally sewn and fixed to the surface of the slab foam 21 in the portion corresponding to the front surface portion 10 (hatched portion in FIG. 2). The urethane film 3 and the inner peripheral surface of the portion forming the front surface portion 10
A cavity space 22 is formed, and a second cavity space 23 is formed by the urethane film 3 and the inner peripheral surface of the portion forming the rear surface portion of the skin 2. The bottom surface of the skin body 2 is formed with a first inlet 24 communicating with the first cavity space 22, a second inlet 25 communicating with the second cavity space 23, and two stay holes 26.

The headrest 1 is manufactured using this skin body 2 as follows. First, as shown in FIGS. 4 and 5, a core material 12 which is previously formed by blow molding from PE and integrally coupled with a stay 11 is arranged in the skin body 2, and the stay 11 is provided with a stay hole 26.
Put out from. Then, the skin body 2 is placed in the mold 4 together with the core material 12, and the mold is clamped.

Next, the first foamed resin is injected from the first injection port 24 and the second foamed resin is injected from the second injection port 25. Here, as the first foamed resin and the second foamed resin, a general urethane foam raw material for headrest is used, and as shown in Table 1, by changing the mixing ratio of the isocyanate component and the polyol component, a soft and hard foamed product can be obtained. Trying to get.

The injection amount of the first foam resin is 50g, the injection amount of the second foam resin is 1
The amount was 80 g, and 10 seconds after the first foamed resin was injected, the second foamed resin was injected. Then, the injection plug 40 closes the injection hole of the mold 4 corresponding to the first injection port 24, and the injection plug 41 closes the injection hole of the mold 4 corresponding to the second injection port 25. 2 The foamed resin is foamed at the same time. Then, due to the difference in foaming pressure between the first foamed resin and the second foamed resin, the urethane film 3
Is expanded toward the second cavity space 23,
As shown in FIGS. 6 and 7, the second cavity space 23
It becomes a convex curved surface shape protruding to the side. In that state, the first
A soft first foam 31 formed of foam resin and a hard second foam 32 formed of second foam resin fill the first cavity space 22 and the second cavity space 23, and the urethane film 3 and the core The material 12 and the skin 2 are integrally connected.

The hardness, the density and the volume occupation rate of the whole of the obtained first foam 31 and second foam 32 were measured, and the results are shown in Table 2. As is apparent from Table 2, the first foam body 31 is soft and the second foam body 32 is hard. And the first foam 31
Accounts for about 20% of the total.

In the obtained headrest 1, the shape of the soft first foamed body 31 forming the front surface portion 10 is such that the central portion 10a is thicker and becomes thinner toward the side portions 10b. Therefore, the second foam 32 is exposed to the influence of the second foam 32 toward the side portion 10b and gradually hardens, so that the hardness does not suddenly change and the tactile feel is excellent and the head supportability is excellent. Further, since the first foam 31 is thick in the central portion 10a,
Soft and feels good.

The headrest was repeatedly manufactured, but no significant change was observed in the numerical values in Table 2, and the reproducibility was excellent. Further, if the injection amount of the first foamed resin and the second foamed resin was constant, the reproducibility of the convex curved surface shape of the first foam 31 was excellent.

Therefore, according to the manufacturing method of this embodiment, the first Since the foam 31 and the second foam 32 can be formed almost at the same time,
The time required for molding is prevented from becoming long. Further, since the shapes and properties of the obtained first foam and second foam are excellent in reproducibility, a foam having desired performance can be stably and easily manufactured. Further, since the conventional mold can be used as it is, the increase in cost required for the mold can be prevented.

(Example 2) Although the bag-shaped skin 2 was used in the above-mentioned Example 1, the manufacturing method of the present invention is not limited to the bag-shaped skin. For example, as shown in FIG. 8, using a sheet-shaped skin 2 ′,
The urethane film 3'may be sewn and fixed to a part of the skin 2 '. Then, when the skin 2'is placed in the lower mold 42 and the upper mold 43 is closed and sandwiched between the lower mold 42 and the upper mold 43 of the skin 2 ', the skin 2'and the urethane film 3'become the first cavity space. 22 'is formed, and the second cavity space is formed by the urethane film 3'and the skin body 2'and the mold surface of the upper mold 43.
23 'is formed.

Then, in the same manner as in Example 1, the first foamed resin is foamed in the first cavity space 22 'and the second foamed resin is foamed in the second cavity space 23'. As shown in FIG. 9, the obtained molded body has a skin 2'on the surface side on which the soft first foam 31 'is present, and a hard second foam 32' on the back side. I have put it out. Such a molded body can be used as a seat of different hardness, an armrest, a lid of a console box, or the like by bringing the back surface side into contact with and fixing the mounted portion.

[Brief description of drawings]

The drawings relate to a manufacturing method of an embodiment of the present invention, FIG. 1 is a perspective view of the obtained headrest, FIG. 2 is a plan view of a used skin, and FIG. FIGS. 4 and 5 are explanatory sectional views showing the structure of the mold before molding, and FIGS. 6 and 7 are moldings corresponding to the AA cutting line and the BB cutting line of FIG. 1, respectively. It is explanatory sectional drawing which shows the structure of a metal mold | die after this and a molded object. FIGS. 8 and 9 relate to the manufacturing method of the second embodiment, FIG. 8 is an explanatory view showing the structures of the skin and the mold, and FIG. 9 is a sectional view of the obtained molded body. 1 ... Headrest, ... Surface material 3 ... Urethane film (partitioning member) 4 ... Mold, 10 ... Front part 11 ... Stay, 12 ... Core material 22 ... First cavity space 23 ... No. 2 cavity space 31 …… first foam, 32 …… second foam

Claims (1)

[Claims] 1. A peripheral portion of a film-shaped partition member is fixed to an inner peripheral surface of a skin member formed in a predetermined shape to form a first cavity space between the skin member and the partition member, and A second cavity space is formed by the other facing inner peripheral surface or the facing mold surface and the partition member, the first foamed resin is foamed in the first cavity space, and the partition member is moved to the second by the foaming pressure. The first foamed body having a convex curved surface is formed by pressing toward the cavity space, and the second foamed resin having a composition different from that of the first foamed resin is foamed in the second cavity space to form the second foamed body. A method for producing a cushion body of different hardness, which is characterized in that the cushion body is formed.