JP3188345B2 - Manufacturing method of skin integral foam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a foam-integral foam product, which is formed by foaming integrally with a plastic skin made by slash molding or the like. It is used in the field of manufacturing automotive interior parts.

[0002]

2. Description of the Related Art A foam-integrated foam product in which the surface of a foam molded product is covered with a plastic skin is commercially available. This is because, when a product is required to have elasticity and light weight, the foam can have its cushioning property and light weight, etc., while the aesthetic treatment of the appearance can be performed by the skin, which is convenient. Conventionally, such a skin-integrated foamed product was manufactured by the following method.
First, the upper mold 6 and the lower mold 7 having desired cavities are manufactured, and the lower mold 7 is provided with a through-hole 72 communicating with the mold surface 71. Also, a plastic skin 8 made by slush molding, vacuum molding, or the like is prepared. Then, the skin 8 is placed on the mold surface 71 (FIG. 8), and then the air existing between the skin and the mold surface is sucked by the vacuum pump 5 to bring the skin 8 into close contact with the mold surface 71 (FIG. 9). Subsequently, a liquid foaming material is injected into the inner surface 81 of the skin while the vacuum is maintained, and foam molding is performed integrally with the skin (prior art 1).

Here, in order to facilitate the positioning of the skin 8 and to enhance the fit to the mold surface 71, cylindrical dowels 74 are planted at regular intervals on the mold upper surface 73 (FIG. 10). There was also one in which a cylindrical recess 82 (FIG. 11) was formed on the outer skin side (prior art 2). Further, by the applicant,
A method of manufacturing a foam-integral foam product in which the skin 8 is held at a correct position on the mold surface 71 to further enhance the sealing property between the skin 8 and the mold surface 71 (Japanese Patent Application Laid-Open No. 4-107109) is also disclosed. Technology 3).

[0004]

However, there are defects in any of the conventional manufacturing methods. In the prior art 1, the skin 8 was easily shifted. In the related art 2 in which the displacement is prevented by the dowel 74, it is difficult to manufacture the skin 8 that fits perfectly with the dowel 74, and the yield is reduced. The skin 8 is likely to be partially stretched during the molding process, particularly when the mold is released from the skin mold. For this reason,
For the dowels 74 at all points, it was extremely difficult to produce a skin in which the cylindrical recesses 82 were accurately aligned. Therefore, if it is within a certain allowable range, dowel 74
However, the dissociation part 9 where the skin 8 was lifted up from the mold appeared (FIG. 12). The range of the dissociation portion 9 was widened, and was prominent in the skin of the skirt portion 75. Since air enters through the gap created by the dissociation section 9, no matter how much the vacuum pump 5 pulls the air, it cannot be pulled (FIG. 13). Thus, the skin 8 did not adhere to the mold surface 71, resulting in a defective product having wrinkles or the like on the product surface.

According to the prior art 3 which is an improvement over the prior arts 1 and 2, there is no particular problem in producing a small product. However, it was not good for large products. When it comes to the skin of a large product, its area is extremely large compared to the skin thickness. Therefore, even if the skin 8 is to be accommodated in the mold surface seal portion 76, the surface is wavy, and somewhere is raised (FIG. 14). Further, the skin seal portion 8 is provided on the mold surface seal portion 76.
Even if the mold surface seal portion 76 has no force to catch the skin seal portion 83,
Places that have already been fitted have come off one after another. Therefore, it was difficult to set the skin 8 on the mold surface 71. Furthermore, since the mold surface seal portion 76 is made of a rigid body, it was inflexible. Even when the skin 8 is slightly deformed, a gap is formed between the skin and the mold surface. Then, air entered from this gap, and the suction force of the vacuum pump dropped rapidly. The decrease in suction force was directly linked to an increase in defective products.

[0006] The present invention solves the above-mentioned problems, and once fitted, the elastic elongated body keeps the adjuster portion securely, so that the adhesiveness between the skin and the mold surface is perfect. It is another object of the present invention to provide a method of manufacturing a skin-integrated foamed product that produces a non-defective product flexibly in response to slight deformation of the skin as well as the like.

[0007]

According to the method of the present invention for producing a skin-integrated foamed product, a plastic skin is disposed on a mold surface of a foaming mold, and the skin and the mold surface are formed by using a through hole communicating with the mold surface. In a method for producing a skin-integrated foamed product, in which a liquid foaming raw material is injected into the inner surface of the skin while applying vacuum suction therebetween, and foamed integrally with the skin, the skirt portion of the foaming mold surrounds the outer periphery of the product molding portion. By providing a groove and fixing an elastic long body having a concave (or convex) cross section that engages with the annular groove, an adjuster portion that fits with the elastic long body is formed on the outer surface of the skin. Then, the adjuster portion is fitted to the elastic elongated body, the outer skin is placed on the mold surface so as to form an annular seal band, and then vacuum suction is applied between the outer skin surrounded by the annular seal band and the mold surface. Injection and foaming of liquid foaming material

[0008] Here, the "elastic long body" is made of an elastic material such as a rubber material, and has a concave cross section, and sets the depressed portion toward the outside of the mold surface (when the cross section is convex, it expands). (Set the outer part toward the outside of the mold surface), which is fixed to the annular groove and arranged so as to surround the outer periphery of the product molded part. The “annular seal band” refers to a sealing band formed by fitting the adjuster portion and the elastic elongated body, and surrounds the outer periphery of the product forming portion.

[0009]

According to the method for producing a skin-integrated foam according to the present invention, the adjuster is fitted into the elastic elongated body so that the shape of the skin matches the shape of the lower mold. Then, in the fitted portion, the elastic long body exerts a force to tighten the adjuster portion by its elastic restoring force, and once fitted, the adjuster portion is securely held. On the other hand, when the skin is deformed or the like, the elastic long body itself copes with the deformation so as to reduce the deformation of the skin. Therefore, the setting of the epidermis to the lower mold proceeds smoothly. An annular seal band formed by such an adjuster and an elastic elongated body is provided on the skirt. By providing the annular seal band on the skirt, as the mold closing progresses, the elastic elongated body and the adjuster section are crushed, even if there is a gap between the adjuster section and the elastic elongated body. The meshing is performed so as to fill the gap, and the airtightness of the annular seal band is further improved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments. (1) Structure of Skin and Foam Mold FIGS. 1 to 6 show an embodiment of a skin and a foam mold used in the method for producing a skin-integrated foam according to the present invention. It is intended to make a skin-integrated foam of instrument panel pad.

The foaming mold A includes an upper mold 1 and a lower mold 2 and forms a product-shaped cavity between the upper mold 1 and the lower mold 2. The lower mold 2 includes upper and lower blocks 2a and 2b having a hollow inside (FIG. 1). The skirt 21 is located on the upper block 2a of the lower mold 2, and an annular groove 22 having a U-shaped cross section is provided near the center of the skirt 21 (FIG. 2). Annular groove 22
Runs on the entire circumference of the lower mold 2, and forms the product forming portion 23a on the mold surface 23.
The outer periphery is surrounded.

Reference numeral 3 denotes an elastic long body made of a rubber material and having a concave cross section (FIG. 3). The elastic long body 3 is fixed to the lower mold 2 by fitting into the annular groove 22 such that the concave portion is exposed on the outer surface. The elastic long body 3 has a shape that fills the annular groove 22 dug into the lower mold 2, and runs over the entire periphery of the lower mold 2 with the surface of the elastic long body 3 coinciding with the surface of the lower mold 2. The elastic elongated body 3 having a concave cross section has a dent width W of about 2 mm.
The depth D is about 5 mm. Reference numeral 24 denotes a lower block 2b of the lower die 2, which is a through-hole penetrating from the hollow portion 25 to the die surface 23 (FIG. 6). The through holes 24 are provided at several places at appropriate intervals depending on the size, shape, and the like of the product forming portion 23a. The suction tube 51 is drawn into the through hole 24 from the side of the lower die 2, and the tip of the suction tube 51 is inserted. The other end of the suction tube 51 is connected to the vacuum pump 5.

Reference numeral 4 denotes a plastic skin placed on the mold surface 23 of the lower mold 2 (FIG. 5). It is molded into the skin of the instrument panel pad by powder slush molding. An adjuster 41 is formed at the position of the skin 4 corresponding to the position of the elastic elongated body 3 fixed to the lower mold 2. It is provided on the outer surface of the skin skirt portion 42 so as to surround the product forming portion 23a. The adjuster portion 41 is integrally formed when the skin is formed.

The adjuster portion 41 is a projection having a convex cross section that fits with the elastic elongated body 3 and is set so as to be slightly tightly fitted with the elastic elongated body 3. This is because the elastic elongated body 3 is elastically deformed and does not work on fitting, and if fitted, the restoring force enhances the sealing property. When the adjuster portion 41 and the elastic elongated body 3 are fitted over the entire circumference, an annular seal band c is formed. When the annular seal band c is completed, this is the product forming section 2
A state is created in which the space between the outer skin 4 and the mold surface 23 is sealed around 3a. By the way, the outer peripheral edge of the skin 4 has reached only before the mold upper surface 231 (FIGS. 4 and 6). Mold upper surface 231
This is because it is not necessary to provide the dowel 74 on the side surface and to form the cylindrical recess 82 to be engaged with the dowel 74 on the skin 4 side. The yield of the skin 4 is improved by eliminating the need for the skin portion on the mold upper surface 231.

(2) Method for Producing a Skin-Integrated Foam Product An embodiment of a method for producing a skin-integrated foam product according to the present invention using the above-mentioned skin 4 and a foaming mold A will be described. First, the skin 4 is prepared and placed on the lower mold 2. Here, they are placed so that their shapes overlap each other (FIG. 4). Then
The adjuster 41 is placed almost directly above the elastic long body 3. After ensuring such a state, the adjuster 41 is pushed down, and the adjuster 41 is fitted into the concave portion of the elastic elongated body 3.

In this case, if the adjuster portion 41 is inserted into the elastic long body 3 at any one position, the adjuster portion 41 is provided with a path, and thereafter, the entire remaining portion can be easily inserted (FIG. 1). This is because the elastic elongated body 3 and the adjuster portion 41 are not separated and independent one by one like the dowels 74, and their cross-sectional shapes do not change and are continuous and elongated. Also, the position of the adjuster 41 due to a manufacturing error or the like is corrected by the elastic elongated body 3 correcting the position of the adjuster 41 and capturing the adjuster 41. It is based on the elastic deformation of the rubber material constituting the elastic elongated body 3. On the other hand, the adjuster part 4
If the elastic long body 3 is fitted into the elastic long body 3, the adjuster 41 is tightened in order to restore the elastic long body 3 that has been elastically deformed. Therefore, the adjuster portion 41 does not come off the elastic elongated body 3 with a slight external force. In this way, the problem that the mated corners come off as in the related art is solved.

As the fitting of the adjuster 41 is advanced,
When the adjuster portion 41 and the elastic elongated body 3 are fitted over all portions, an annular seal band c is formed (FIG. 1).
Thus, the space between the outer skin 4 surrounded by the annular seal band c and the mold surface 23 of the product forming portion 23a is in a state of being isolated from external air.

Thereafter, the vacuum pump 5 is started. By the operation of the vacuum pump 5, a vacuum is applied between the mold surface 23 and the skin 4 surrounded by the annular seal band c, and the air present therein is discharged to the outside through the through hole 24 and the suction tube 51. You. Therefore, the skin 4 located at the product forming portion 23 a comes into close contact with the mold surface 23.

Next, a liquid foaming raw material F composed of a polyurethane foam raw material is injected into the inner surface of the skin while suction is maintained by the vacuum pump 5 and such a state is maintained. Then, after injecting a predetermined amount of polyurethane foam material, the upper mold 1
Close. The skirt portion 21 has a mortar shape with respect to the closing direction, and the upper mold 1 and the lower mold 2
The annular seal band c is engaged with the annular seal band c so as to sandwich the annular seal band c. Therefore, the adjuster unit 4
Even if a gap is formed between the elastic body 1 and the elastic elongated body 3, as the upper mold 1 closes, the gap is crushed and filled. As the vacuum pump 5 continues to work, a vacuum is completely applied between the mold surface 23 corresponding to the product molding portion 23a and the skin 4, and the skin 4 is completely adhered to the mold surface 23 during foam molding. (FIG. 6).

Thereafter, the upper mold 1 and the lower mold 2 are clamped,
The foam is formed integrally with the skin 4. After the skin integral foam molding is completed, the upper mold 1 is opened. Then, when the completed skin integral foam is taken out from the lower mold 2, a series of molding steps is completed. Here, at the time of taking out the skin-integrated foam, a part of the adjuster portion 41 is separated from the elastic elongated body 3 and if the adjuster portion 41 is lifted up, a path is established by the lifting portion of the adjuster portion 41. The part 41 is continuously and successively separated from the elongated elastic body 3. Therefore, it is easy to remove the foam-integrated foam. Finally, the outer skin 4 outside the product forming portion 23a is cut off to obtain a desired final product. Note that the elastic elongated body 3 remains fixed to the annular groove 22 of the lower die 2. This is for use in the production of the next skin integral foam. The shape in which the elastic elongated body 3 is deformed in the molding process is elastically recovered and returns to its original shape.

(3) Effects of the Embodiment According to the method for producing a skin-integrated foamed product according to the above-described embodiment, the skin 4 can be easily set on the mold surface 23. Epidermis 4
Is different from the case where it is simply placed on the mold surface seal portion 76 (prior art 3), once it is set on the elastic elongated body 3, it does not come off due to the elastic clamping force of the elastic elongated body 3. In the case where the dowels 74 are provided (prior art 2), it is difficult to mount the dowels 74 while checking the positions one by one in two-dimensional directions. However, in this embodiment, if the adjuster portion 41 is fitted into the elastic elongated body 3 even in a part, the elastic elongated body 3
Since the adjuster portion 41 that has not yet been fitted into the concave groove is already close to the concave groove, the adjuster portion 41 and the elastic elongated body 3 can be simply moved by moving the adjuster portion 41 from above.
Could be achieved without difficulty. On the other hand, it was also easy to remove the integral foam from the lower mold 2 after integral molding of the skin. When the foamed product with the dowel 74 is pulled up, when pulling up the skin-integrated foam, the dowel 74 cannot be pulled up as it is and must be removed by bending the cylindrical portion of the dowel 74. Became. On the other hand, in this embodiment, the adjuster portion 41 is in a transitional state in which it is separated from the fitting if one portion comes off, and the adjuster portion 41 provides a path, so that the adjuster portion 41 can be separated without resistance only by pulling up along the elastic long body 3. We were able to. In this way, such work is facilitated and contributed to an improvement in productivity.

Then, for some deformation of the epidermis 4,
Since the elastic long body 3 itself is deformed and absorbs a dimensional error of the skin 4, the dimensional tolerance of the skin 4 is widened, and the defective rate is reduced. Furthermore, according to the present example, excellent airtightness was obtained. The adjuster portion 41 and the elastic elongated body 3 are engaged with each other to form an annular seal band c. Therefore, unlike the case where the skin 4 is simply placed on the lower mold 2, the space between the mold surface 23 and the skin 4 is cut off from the outside air by the annular seal band c. By ensuring this airtightness, the vacuum pump 5 worked effectively. As a result, the skin 4 adheres to the mold surface 23 neatly,
It was possible to produce a skin-integrated foam having excellent quality without wrinkles on the surface.

In addition, the skirt portion 21 has an annular seal band c.
Is formed, and the upper mold 1 and the lower mold 2 are rubbed at this portion. Therefore, even if a gap is formed between the adjuster portion 41 and the elastic elongated body 3, the gap is formed in the mold closing process. Was crushed. Thus, the annular seal band c is
The sealing performance was further improved, resulting in a good product. The formation of the annular seal band c in the skirt portion 21 eliminates the need to provide the through hole 24 in the upper block 2a, and reduces the manufacturing cost of the lower mold 2. In addition, since vacuum is applied only to a necessary narrow range, the power is increased, the adhesion of the surface 4 to the mold surface 23 is further increased, and the product yield is improved.

In the present invention, the present invention is not limited to the above-described embodiment, but can be variously changed within the scope of the present invention depending on the purpose and application. For example, the adjuster section 41 can have a shape as shown in FIG. In such a case, the “U” -shaped portion of the adjuster portion 41 has elasticity, and the adhesion to the elastic elongated body 3 is further increased. on the other hand,
The elastic elongated body 3 may have a convex cross section, and the adjuster 41 may have a concave cross section. This is because, similarly to the embodiment, the annular sealing band c can be formed by the elastic elongated body 3 and the adjuster portion 41. Furthermore, if the shape of the concave (or convex) cross section of the elastic elongated body 3 has a depressed portion (or swelled portion) and can be fitted with the adjuster portion 41 which is the fitting target, the specific shape thereof is used. Regardless of the shape. The material of the elastic long body 3 is not limited to the rubber material, but may be replaced with a sponge or the like. Also, instead of the suction tube 51, a hole is made in the lower block 2b of the lower die 2, and a suction pipe is connected to this,
A configuration that communicates with the through hole 24 via the hollow portion 25 may be adopted. The spread of the skin 4 is not limited to the embodiment, and may be of such a size as to spread on the mold upper surface 73.

[0025]

As described above, according to the method for producing a skin-integrated foamed product according to the present invention, even if the skin is slightly deformed, not only the elastic long body can absorb this deformation, but also the skin can be securely attached to the mold surface. Since foam molding is performed so as to be integral with the skin while being in close contact with the skin, an excellent effect is exhibited such that a skin-integrated foam product having a good product appearance can be produced.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a skin and a lower mold used in an example.

FIG. 2 is a schematic perspective view showing the periphery of a lower annular groove in FIG. 1;

FIG. 3 is a schematic perspective view showing the elastic elongated body of FIG.

FIG. 4 is a partial cross-sectional view showing a state where an epidermis is placed on a lower mold in the embodiment.

FIG. 5 is a partial perspective view of a skin used in the example.

FIG. 6 is a schematic cross-sectional view showing a liquid foaming raw material during foaming in an example.

FIG. 7 is a partial sectional view showing another embodiment of the skin.

FIG. 8 is a schematic explanatory diagram of a conventional technique 1.

FIG. 9 is a schematic explanatory diagram of a conventional technique 1.

FIG. 10 is a schematic explanatory diagram of a conventional technique 2.

FIG. 11 is a partially enlarged view of the epidermis in Prior Art 2.

FIG. 12 is a partially enlarged view around a dowel in Conventional Technique 2.

FIG. 13 is an explanatory cross-sectional view showing a set state of a lower mold and an epidermis according to Conventional Technique 2.

FIG. 14 is a schematic explanatory diagram of a conventional technique 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Skirt part 22 Annular groove 23 Mold surface 23a Product forming part 24 Through hole 3 Elastic long body 4 Skin 41 Adjuster part A Foaming mold c Annular sealing band F Liquid foaming raw material

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI B29K 105: 04 B29L 31:58 (58) Investigated field (Int.Cl. ⁷ , DB name) B29C 39/10 B29C 39/22 -39/26 B68G 7/06 B60N 2/48 A47C 7/18

Claims (1)

(57) [Claims] 1. A plastic foam is placed on the mold surface of a foam molding die, and a liquid foaming material is injected into the skin inner surface while applying vacuum suction between the skin and the mold surface using a through hole communicating with the mold surface. In the method for producing a skin-integrated foam product integrally foam-molded with the skin, an annular groove surrounding the outer periphery of the product molding portion is provided in the skirt portion of the foam molding die, and a concave section (or convex section) engaging with the annular groove is provided. Part) While fixing the elastic long body of the shape,
By forming an adjuster portion that fits with the elastic elongated body on the outer surface of the skin, the adjuster portion is fitted on the elastic elongated body, and the skin is placed on the mold surface so as to form an annular seal band. Then, a liquid foaming raw material is injected and foamed while vacuum suction is applied between the outer skin and the mold surface surrounded by the annular seal band, and a method for producing a foam integrated with the skin.