JPH066297B2 - Manufacturing method of different hardness headrest - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a headrest of different hardness having a soft portion and a hard portion.

[Prior Art] A headrest of an automobile is required to have good supportability for supporting the head and also have a good feel to the head. However, it is necessary to make it hard in order to satisfy the holding property, and it is necessary to make it soft in order to improve the feel, so it is difficult to realize both of these performances in one molded product.

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.
If it does in this way, both the above-mentioned performances 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 foamed molded product (3) A method of partially varying the inner 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.

The present invention has been made in view of such circumstances,
The object is to form a headrest of different hardness with high productivity and a small number of steps, and stable quality.

[Means for Solving the Problems] A method of manufacturing a different hardness headrest according to the present invention which solves the above problems, includes a first die forming a front surface portion of a headrest, and a first die forming a rear surface portion by being clamped with the first die. The first mold, the second mold, and the third mold arranged between the first mold and the second mold.
A method for manufacturing a different hardness headrest having a soft portion in at least a central portion of a front surface portion and a hard portion in the remaining portion by injecting a foamed resin into a cavity formed by a mold and a third mold to perform foam molding, The mold has a partition wall protruding from the mold surface toward the third mold and forming a closed space between the mold and the third mold, and a soft foamed resin is provided in the partition wall and the first cavity formed by the first mold and the third mold. Along with the injection, a hard foam resin is injected into the partition wall and the second cavity formed by the second mold and the third mold to perform foam molding.

In the manufacturing method of the present invention, a partition wall is provided on the inner surface of the molding die,
A feature is that the cavities are divided by partition walls and different foamed resins are foamed and molded in the respective cavities. As a result, the soft portion and the hard portion can be formed at the same time, so that the molding cycle can be shortened as compared with the method disclosed in JP-A-63-218317.

The partition wall projects from the first mold and is in contact with the third mold. Here, if the tip of the partition wall is configured not to contact the third mold,
The soft foamed resin and the hard foamed resin are mixed together at that portion, and since the respective foamed resins have different internal pressures, voids and cell roughness occur in the molded body due to the difference in the internal pressures. Therefore, it is desirable that the partition wall is in close contact with the third mold and has a high sealing property. It is also conceivable that the partition walls may be projected more than the third type. However, in this case, the tip of the partition wall is located near the front portion of the headrest, so that defects are likely to appear. Therefore, it is configured so as to project from the first mold toward the third mold so as to be located in an inconspicuous interior even if a defect should occur.

The partition wall may be made of the same material as that of the first mold, but it is preferable that the partition wall is in close contact with the third mold, and thus the partition wall can be formed of elastic metal, resin, rubber or the like.

By the way, in the case of forming a headrest having a hollow portion inside, if constituted as described above, the molded body will be divided by the mixture of the partition wall and the mold surface of the third mold, and the soft portion and the hard portion will be separated. Become a body. However, it is possible to easily form a different-hardness headrest in which the soft portion and the hard portion are integrated by coating a skin formed in a predetermined bag shape in advance or by adhering it to a core material. it can.

It is also possible to integrate them at the time of molding. For example, it is desirable to interpose a binder between the tip of the partition wall and the third mold surface. It is sufficient that the binder can be integrally bonded to the foamed resin, and it is preferable that the binder is impregnated with the foamed resin such as a woven cloth, a non-woven cloth, a net or a foam. When a foam such as a slab foam is used, the foamed resin can be impregnated and solidified to be integrally bonded, and the foamed resins on both sides can be further prevented from being mixed with each other. In the obtained headrest, the portions divided by the partition wall are connected from both sides by the binder that is impregnated with the foamed resin and solidified, so that the soft portion and the hard portion are prevented from being separated from each other.

Further, when the headrest is integrally formed by using the core material having the stay as the insert, the core material functions as the third mold. In this case, the binder as described above may be used, but the core resin may be made of a material having excellent adhesiveness with the foamed resin, or an adhesive may be applied to the surface of the core material to form the core of the foamed resin and the core. It is desirable that the material and the material are joined together. Thereby, the separation of the soft part and the hard part can be prevented without using a binder.

[Operation and Effect of the Invention] In the method of manufacturing a different hardness headrest of the present invention, the first cavity is formed between the first mold, the partition wall and the third mold, and the second cavity is formed between the partition wall, the second mold and the third mold. It is formed. The first cavity and the second cavity are independent of each other because the partition wall is in contact with the third mold via the bonding material. Then, a soft foamed resin is injected into the first cavity and a hard foamed resin is injected into the second cavity, respectively, and foam molding is performed. Since the respective foamed resins can be foamed at the same time, the time required for molding is almost the same as that in the case of molding a headrest of the same hardness in the related art, and the cycle time is short. Moreover, the number of steps is smaller than that of the conventional method.

When the binder is used, the respective foamed resins are integrally bonded to the binder from both sides of the partition wall, so that the molded body is prevented from separating at the partition wall, and the soft part and the hard part are bonded to each other. It is possible to obtain a different hardness headrest integrally connected with each other.

Further, when the core material that can be joined to the foamed resin is used as the third mold, the soft portion and the hard portion are integrally joined to the core material without using a binder, so that the whole is integrated. It is possible to easily form the different hardness headrest coupled to the.

Therefore, according to the manufacturing method of the present invention, a headrest having different hardness can be manufactured with high productivity and stable quality.

[Examples] Hereinafter, specific examples will be described.

(Example 1) FIGS. 1 and 2 are sectional views of a molding die used. This mold includes a first mold 1, a second mold 2 clamped to the first mold 1, and a third mold 3 arranged in a cavity formed by the first mold 1 and the second mold 2. It is composed of

Also, a perspective view of the headrest formed in FIG. 5 is shown. The headrest 5 includes a front portion 50 including a central portion 50a that supports the occipital region of the human body and side portions 50b that extend slightly curved to the left and right sides of the central portion 50a and wrap around the occipital region. And a curved rear surface portion 54 connecting the pair of side surface portions 51, the upper surface portion 52 and the lower surface portion 53. A groove 55 extending from the edge of one side portion 50b to the upper surface portion 52 and extending from the upper surface portion 52 to the edge portion of the other side portion 51 is formed, and has an internal space into which the core material is inserted. .
A soft portion 60 is formed in front of the groove 55, and a hard portion 61 is formed behind the groove 55.

The first mold 1 has a design mold surface 10 that forms a front surface portion 50 of the headrest. A substantially U-shaped plate-shaped partition wall 11 projects from the design mold surface 10 toward the third mold 3.
The partition wall 11 forms an acute angle from the boundary between the mold surface forming one side portion 50b of the headrest 5 and the mold surface forming the side surface portion 51 with respect to the mold surface forming one side portion 50b. It projects and projects substantially at right angles to the mold surface forming the upper surface portion 52, and projects at an acute angle to the mold surface forming the other side portion 50b. This partition wall 11 is in contact with the third mold 3, and the first partition wall 1 and the partition wall 11 and the third mold partition 3 form the first partition wall.
The cavity 13 is formed, and the second mold 23, the partition wall 11, and the third mold 3 form the second cavity 23. A first resin injection port 14 and a second resin injection port 24 are formed in the first cavity 13 and the second cavity 23, respectively.

The headrest 5 is formed as follows using the mold configured as described above.

First, when the first mold 1, the second mold 2, and the third mold are combined, a tape-shaped bonding material 4 is interposed at the contact portion between the partition wall 11 and the third mold 3 as shown in FIG. The tape-shaped binder 4 is composed of a nonwoven fabric 40 and a slab foam layer 41 laminated and bonded to the nonwoven fabric 40, and the slab foam layer 41 is arranged so as to contact the third mold 3.

Next, a soft urethane foam resin is injected from the first resin injection port 14 and a hard urethane foam resin is injected from the second resin injection port 24. Then, the first resin injection port 14 and the second resin injection port 24 are closed by the injection plug 6 and heated and held. This causes the soft urethane foam resin to foam and
The cavity 13 is filled, and the urethane foam resin of the imperial family is foamed to fill the second cavity 23.

At this time, in the contact portion between the partition wall 11 and the third mold 3, the soft urethane foam resin and the hard urethane foam resin are separated from each other.
The binder 4 is impregnated from both sides of each of these to solidify. Here, since the slab foam 41 contains a large number of closed cells, a sealing effect is obtained, and the occurrence of defects due to a difference in internal pressure between the resins on both sides is prevented.

After the foaming is completed, the first die 1, the second die 2 and the third die 3 are separated, and the headrest 5 is released. FIG. 4 shows a sectional view of the main part of the obtained headrest 5. A soft portion 60 formed of a soft urethane foam resin and a hard portion 61 formed of a hard urethane foam resin are formed, and a groove 55 formed by the partition wall 11 is formed at the boundary between the soft portion 60 and the hard portion 61. Is intervening. However, at the tip of the groove 55, there is the binder 4 which is reinforced by impregnating and solidifying the foamed resin, and the soft portion 6
The 0 and the hard part 61 are not separated but are connected and integrated by the bonding material 4.

Therefore, in the obtained headrest 5, the soft part 60 and the hard part 61 are not separated but are integrated as a whole.
The central portion 50a is soft and has a good feel. Further, in the side portion 50b, the thickness of the soft portion 60 becomes thinner as the distance from the central portion 50a increases, so the hardness of the hard portion 61 transmitted to the side portion 50b via the groove 55 gradually increases as the distance from the central portion 50a increases. It feels to be stiff, has no discomfort, and has excellent head retention.

The obtained headrest 5 is a product in which a core material having a stay is inserted into the internal space, and the surface thereof is covered with a skin formed into a predetermined bag shape by sewing or the like.

(Example 2) This example is the same as Example 1 except that the binder 4 was not used. Therefore, in the obtained headrest, the soft portion 60 and the hard portion 61 are separated by the groove 55 and are separate bodies. However, by mounting the core material and the outer skin, the whole can be integrated. Further, if the soft portion 60 and the hard portion 61 are joined to the core material with an adhesive or the like, they can be more integrally joined.

(Embodiment 3) In this embodiment, as shown in FIG. 6, a resin core material 7 having a stay 70 as a third mold was used, and the binder 4 was used.
The same as Example 1 except that was not used. This core material 7 is made of ABS resin and has excellent adhesiveness with urethane foam resin. Therefore, in the obtained headrest, as shown in FIG. 7, the soft portion 60 and the hard portion 61 are firmly joined to the core member 7, respectively, and are wholly integrally joined.

[Brief description of drawings]

1 to 5 relate to a manufacturing method according to an embodiment of the present invention. FIGS. 1 and 2 are cross-sectional views of a molding die used respectively, and FIG. 3 shows a partition wall and a third die. FIG. 4 is an enlarged sectional view of an essential part of the contact portion, FIG. 4 is an enlarged sectional view of an essential part of the obtained headrest, and FIG. 5 is a perspective view of the obtained headrest.
FIGS. 6 and 7 relate to the third embodiment of the present invention, FIG. 6 is an enlarged cross-sectional view of an essential part of the contact portion between the partition wall and the core material (third type), and FIG. 7 is the obtained headrest. FIG. DESCRIPTION OF SYMBOLS 1 ... 1st type 2 ... 2nd type 3rd type 4 ... Binding material 5 ... Headrest 6 ... Injection plug 7 ... Core material (3rd type) 10 ... Mold surface 11 ... Partition wall 13 ... 1st cavity 14 ... 1st resin Injection port 23 ... Second cavity 24 ... Second resin injection port 40 ... Nonwoven fabric 41 ... Slab foam 50 ... Front part 55 ... Groove 60 ... Soft part 61 ... Hard part

Claims (3)

[Claims] 1. A first die that forms a front surface of a headrest, and a second die that is clamped to the first die to form a rear surface.
Using a third mold arranged between the first mold and the second mold,
A different hardness headrest having a soft portion in at least the central portion of the front portion and a hard portion in the rest by injecting a foamed resin into the cavity formed by the first die, the second die and the third die Wherein the first mold has a plate-shaped partition wall protruding from the mold surface toward the third mold and forming a closed space between the first mold and the partition wall, and the partition wall and the first partition wall. A soft foamed resin is injected into the first cavity formed by the mold and the third mold, and the partition wall and the second mold are formed.
A method for manufacturing a different hardness headrest, characterized by injecting a hard foam resin into a mold and a second cavity formed by the third mold to perform foam molding. 2. A sheet-shaped coupling material capable of coupling with the foamed resin is interposed at an abutting portion between the partition wall and the third mold, and the soft portion and the hard portion are integrated via the coupling member. The method of manufacturing a different hardness headrest according to claim 1, wherein the headrests are connected in series. 3. The third type is a core material that can be bonded to the foamed resin, and the soft portion and the hard portion are joined and integrated with the core material. Manufacturing method of different hardness headrest.