JPS63242606A - Manufacture of foamed resin molded body with skin material - Google Patents

Abstract

PURPOSE:To manufacture a foamed resin molded body with a skin material by a method wherein the bag-shaped skin material is produced by sewing sheet-like material with expandable thread and, after the resultant skin material is arranged in a forming mold, foaming resin is poured in the mold so as to mold the molded body, the interior of the skin material of which is filled with the resin. CONSTITUTION:A sheet-like material 1 has a skin body 10 on its one side and a fluid shielding layer 12, which is integrally bonded on the other side or on the rear surface side of the skin body. The material 1 is cut into predetermined developed shapes. A plurality of the cut sheet-like materials 1 are sewn by expandable thread 2 so as to produce a bag-shaped skin material, and the expandable thread 2 at sewn part is expanded at least radially. Under the condition that the expandable thread is held in the expanded state, the skin material is arranged in a mold 6 so as to pour foaming resin from the opening of the skin material 1' in order to press the skin material against the molding surface of the mold by means of the blowing pressure of the foaming resin and at the same time to fill the interior of the skin material for forming a molded body. As a result, gap between the sheet-like material and the thread is prevented from developing, when tensile force is applied to the skin material at time of forming. Thus, the oozing-out of the foamed resin can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a foamed resin molded article having a skin material such as cloth or leather. The present invention is used, for example, to manufacture interior parts such as headrests, armrests, and seats for automobiles.

[Prior art 1] Conventionally, in order to manufacture headrests used for automobile seats, for example, a foam molded product of a predetermined shape is molded from foamed urethane resin, etc., and then a separately formed bag-shaped skin material is covered. It is generally manufactured using

However, in the above-described manufacturing method, since the molded body and the skin material are separate bodies, a gap may be created between the two, or wrinkles may occur in the skin material, which may impair the appearance. And even after covering it, troublesome processing such as sewing is required.
It required a lot of man-hours. Furthermore, depending on the shape of the molded product, it may be impossible to cover it with a skin material, making it impossible to freely select a design shape. Furthermore, when covering with the skin material, the convex parts of the molded body may be compressed and the shape may change, so the molded body must be made harder than necessary.
In some cases, the feeling during use was poor.

In order to prevent such problems, a manufacturing method in which a skin material is placed in a mold and the molded product is integrally foamed has been studied in recent years. However, if the skin material is cloth, the gas during molding will pass through the skin material, making it difficult for the foaming pressure to be transmitted to the skin material, making it difficult to obtain a product with the desired shape, and the foamed resin will penetrate to the surface of the skin material. and express it.

Therefore, in Japanese Patent Application No. 61-179252 (unknown), the applicant sewed a sheet-like material in which a gas-shielding layer and a cloth-like material were integrally joined as a skin material, We have proposed a manufacturing method that applies pressure to the skin material to give it a predetermined shape, and also prevents the skin material from being impregnated with foamed resin.

[Problems to be Solved by the Invention] However, in such a manufacturing method, when the pressure of foaming is transmitted to the skin material, a large tensile force acts on the skin material, and in the sewing area, the needle hole expands and the thread A gap is created between the material and the sheet material. Therefore, the foamed resin oozes out from the gap onto the surface of the skin material as shown in FIG. 7, resulting in a loss of quality and failure. Therefore, in order to prevent such problems, there is a method of sealing the seams by placing tape on the prepared part after sewing, but it is not easy to ensure that the tape etc. runs along the sewn part. In some cases, resin oozed from the seams due to poor sealing.

The present invention was made in view of these circumstances, and
A foamed resin molded article having a skin material that can prevent gaps from forming between the sheet-like material and threads when tensile force is applied to the skin material during molding, thereby preventing foamed resin from seeping out. et al. provide a manufacturing method.

[Means for Solving the Problems] The method for producing a foamed resin molded article having a skin material according to the present invention comprises a sheet-like molded article consisting of a skin body and a fluid shielding layer integrally joined to the back side of the skin body. Cutting the material into a predetermined spread shape, and cutting multiple sheets of material using expandable threads.
'Il manufacturing process to form a bag-shaped skin material with JL and 1m'
An expansion step in which the expandable thread of the sewn part sewn in the Fj process is expanded at least in the radial direction, and a skin material is placed in a mold and foamed from the opening of the skin material while maintaining the expanded state of the expandable thread. A molding process in which resin is injected and the skin material is pressed against the surface of the mold by the foaming pressure of the foamed resin to form a molded body that fills the inside of the skin material, and a molding process in which the mold is opened and covered with the skin material. It is characterized by a demolding process for removing the body.

As the skin material, materials similar to those used for conventional skin materials, such as woven fabric, non-woven fabric, leather, and resin, can be used.

The fluid shielding layer shields gas or foamed resin, and may have the function of pressing the skin against the mold surface in response to the foaming pressure during molding. Its gas permeability can be selected depending on the foaming pressure.

This fluid shielding layer is made of a soft material, and can be made of, for example, a resin film, a foam made of closed cells, or the like. Note that it is desirable to select a fluid shielding layer that has good bonding properties with the foamed resin.

For example, when the foamed resin is a urethane resin, the fluid shielding layer is preferably formed from a polyurethane film.

The sheet-like material is made by joining the skin body and the fluid shielding layer. The skin and the fluid shielding layer can be bonded using a laminating method such as adhesive treatment, welding treatment, or pressure bonding treatment.

It is desirable that a thick soft foam layer be disposed between the skin and the fluid shielding layer or on the surface of the fluid shielding layer. In this way, it will be possible to maintain its softness and have excellent shape retention, and the skin material will have excellent shape retention performance in the mold, so defects caused by misalignment of the skin material during molding can be avoided. It can be prevented. Note that it is advantageous to use a foam made of closed cells for the fluid shielding layer because it provides excellent shape-retaining performance without the need for a soft foam layer.

In the cutting process, the sheet material is cut into the developed shape of the desired product.

The N manufacturing process is a process in which a plurality of sheet materials cut in the cutting process are cut into mwJ+ to form a bag-shaped skin material.

One feature of the present invention is that an expandable thread is used as the thread used in this sewing process.

Expandable thread refers to a thread whose diameter at least expands after sewing. For example, threads that contain a water-absorbing resin and expand by absorbing water can be used.

Acrylate-based polymers, vinyl alcohol-acrylate copolymers, etc. are known as such water-absorbing resins, and these water-absorbing resins can be coated on conventional threads, or yarns made of these water-absorbing resins can be ! A thread that expands upon absorption of water can be formed by twisting I fibers together.

It is also possible to use threads that contain a thermally expandable material and expand due to heat. As this thermally expandable material, for example, a material obtained by kneading a blowing agent into a thermoplastic resin can be used. Such materials can then be used alone or in combination with conventional yarns as described above to form thermally expandable yarns.

Furthermore, a spun yarn consisting of a base and a cilia portion formed on the surface of the base can also be used. If such a thread is used, the cilia will be inserted into the needle hole and sewn with the cilia parallel to the base, and the cilia will stand up after sewing.
The diameter of the thread is in an expanded state.

The expansion step is a step in which the expandable threads of the sewn II part are expanded by means corresponding to the expansion means of each expandable thread. For example, when the expandable yarn contains a water-absorbing resin, the expandable yarn can be made to absorb water by keeping the skin material under humid conditions for a certain period of time or by directly contacting it with water. In addition, when the material contains a thermally expandable material, it is heated to a temperature higher than the temperature at which the material expands thermally. In the case of spun yarn, it expands automatically during sewing.

In addition, when using a spun yarn, it is also preferable to use one containing a thermoplastic resin that melts when heated in the cilia portion. When the thermoplastic resin is melted by heating after the sewing process, the thermoplastic resin flows and fills the gap between the skin material and the thread. This further prevents gaps from forming when tensile forces are applied. Furthermore, there are many cases where the expandable thread and the surrounding sheet-like material come into contact with each other at the seams, and oozing of the foamed resin can be further prevented.

In the molding process, the skin material sewn with expandable thread is placed in a mold, and foamed resin is injected from the opening of the skin material. Here, as the foamed resin, conventionally used resins such as polyurethane, polystyrene, polyvinyl chloride, polyethylene, and polypropylene can be used as they are. In addition, foaming means include fluorocarbons, methylene chloride,
Conventional methods can be used, such as adding a blowing agent such as butane, or using a reaction product gas such as carbon dioxide produced by the reaction of water and isocyanate. Then, the foamed resin is foamed by means such as heating to form a molded body filling the inside of the skin material.

The most important feature of the present invention is that this molding step is carried out while the expandable thread is kept in an expanded state. When the expandable thread is expanded, the sheet material surrounding the expandable thread and the surface of the expandable thread are in pressure contact at the seam portion, and the expansion of the expandable thread is regulated by the peripheral wall of the needle hole. . Further, the needle hole is expanded by the expansion of the expandable thread, and the inside of the needle hole is filled with the expandable thread. Therefore, when a tensile force is applied to the sheet-like material due to foaming of the foamed resin, the expandable thread expands further in the radial direction, or the needle hole is already expanded and is prevented from expanding. It is assumed that this prevents the formation of a gap between the sheet-like material and the expandable thread, and prevents the foamed resin from seeping out from the seams.

Then, the product is taken out in the demolding step, and one cycle of the manufacturing method of the present invention is completed.

[Operations and Effects of the Invention] In the manufacturing method of the present invention, the skin material is sewn with expandable threads. Then, in the molding process, the foamed resin is foamed while the expandable thread is maintained in an expanded state.

During the molding process, the skin material expands due to the pressure of foaming, and a tensile force acts on the seam area, causing the needle hole to expand. However, at this time, the expandable thread, whose expansion was limited to M on the peripheral wall of the needle hole, expanded further and blocked the enlarged needle hole.
Alternatively, since the needle hole is already in a widened state, it is assumed that it does not widen any further and that the foamed resin is prevented from seeping out from the seam.

That is, according to the manufacturing method of the present invention, it is possible to reliably prevent the foamed resin from seeping out from the seam portion of the skin material during molding, resulting in defects, and it is possible to reduce the defect rate.

[Example] A detailed explanation will be given below using actual cell examples. In this example,
The manufacturing method of the present invention is applied to the manufacturing of a headrest placed above the seat of an automobile.

(1) Example 1 (Cutting process) As shown in Fig. 1, a urethane-based soft foam (slab foam) 11 with a thickness of 3cm is adhered to the back side of a woven fabric 10 with a thickness of 211Im, and a soft Thickness 3 on the surface of the foam 11
A sheet-like material 1 was prepared in which a polyurethane film 12 serving as a 0 μm gas shielding layer was laminated by heat fusion. This sheet-like material 1 was then cut into the developed shape of the intended headrest to obtain a plurality of partial sheet-like materials.

(Sewing process) Water absorbent resin (rNY1010J manufactured by Sumitomo Chemical Co., Ltd.) 3
00 parts by weight and 100 parts by weight of EPDM (r Nisprene 512 manufactured by Sumitomo Chemical Co., Ltd.) were kneaded with a roll,
gIv of resin liquid with solid content of 25% by weight dissolved in toluene.
J-shita. This resin liquid was applied to a 600 denier polyester thread at a coating weight of 0.08 o/m to form a 1350 denier expandable thread 2.

Next, as shown in Fig. 2, the above-mentioned partial sheet-like material is aligned with the center side of the headrest, leaving the bottom part of the headrest, and is sewn with the above-mentioned expandable thread 2 using a sewing machine (#18) with a pitch of 4.
The material was sewn using a sewing machine using sm+, and a bag was sewn into the desired headrest shape to obtain a skin material of 1゜.

(Expansion Step) The skin material 1' was left in an 80J atmosphere with a humidity of 90% for 1 hour to allow the expandable thread 2 to absorb water. It is known that under these conditions, the weight of the expandable yarn 2 is 1.5 times, and its linear expansion in the radial direction is about 1.2 times.

(Forming process) While maintaining the expanded state of the expandable thread 2, as shown in FIG. inserted inside. Then, as shown in FIG. 4, the mold was placed in the mold 6 and the mold was clamped so that the injection lower of the mold 6 and the opening of the skin material communicated with each other.

Then, from the injection lower, 80 parts by weight of polyether polyol (Sumifen 3063J, manufactured by Sumitomo Bayer Urethane Co., Ltd.) and polymer polyol (rPOP31-2
8J, manufactured by Mitsui Toatsu Chemical Co., Ltd.) 20 heavy lifting parts, distilled water as a blowing agent 4.0 heavy lifting parts, triethylenediamine (r
DABcO33LVJ, manufactured by Nippon Nyukazai Co., Ltd.)1.
5 parts by weight, and silicone surfactant (rsRX-
274C, manufactured by Toray Silicone Co., Ltd.), and crude diphenylmethane diisocyanate (r44V-20J, Sumitomo Peyer urethane).
Co., Ltd.) 7 to toluene diisocyanate (rT
D l-80J, manufactured by Sumitomo Bayer Urethane Co., Ltd.)
A foamed polyurethane resin material mixture was injected, in which a curing agent component was mixed at an IN ratio of 3:3, and the mixture was 65:35 by weight.

In addition, since the skin material 1' had a slab foam layer, it was placed reliably along the shape of the mold surface in the mold, and had excellent shape retention performance.

Then, the mold was heated to about 40° C. and six valves were kept open. As a result, the foamed polyurethane resin material mixture has a volume of approximately 2
It expanded and hardened to 0 times. At this time, the urethane film 12
Since it is impermeable to gas, the skin material 1' is pressed against the mold surface by the pressure of foaming the foamed polyurethane resin, and in this state, the foamed resin fills the inside of the skin material 1' and hardens, causing the foamed resin to ooze out from the seams. did not occur.

(Mold removal process) After the polyurethane foam resin had hardened, the mold was removed and a headrest made of a molded body covered with a skin material was taken out.

In the obtained headrest, as shown in FIG. 5, which shows a cross section of the main part, the molded body 8 was integrally joined to the urethane film 12, and the inside of the skin material 1' was densely filled.

And wrinkles on the surface of the skin material 1', polyurethane foam 81
There was no oil seepage, and the headrest was in good shape, following the mold surface.

In addition, in the molding method using foamed resin, the heavier the weight of the molded product in the same volume, the higher the foaming pressure, and therefore the resin leakage from the II parts is more likely to occur. Therefore, the level of rlm of the molded body was determined in five stages from 230 to 310 g, and a headrest was manufactured in the same manner as above. As a result, as shown in the table, no resin leaked from the seams in any case.

(2) Example 2 In this example, a foaming agent was added to the 600 denier polyester thread used in Example 1 as the thread used in the sewing process.
Cell microphone CAP500J (E Kyokasei Co., Ltd. 1)
A thread coated with 0.0859/m of EVA (ethylene vinyl acetate) Evatate D2021J (manufactured by Sumitomo Chemical Co., Ltd.) containing 1.0% by weight of ll) was used. The procedure is the same as in Example 1 except that the EVA was heated to foam and the thread was expanded, followed by a molding process.As shown in the table, the headrest obtained in this example also had seams. No exudation of foamed resin was observed.

(3) Example 3 In this example, spun yarn (100%
The procedure was the same as in Example 1 except that the molding step L was carried out using polyester thread (#8, manufactured by Gunze Co., Ltd.). As shown in FIG. 6, this spun yarn 9 consists of a base portion 90 and a cilia portion 91. During sewing, the cilia portion 91 is pressed against the peripheral wall of the needle hole and elastically deforms along the base 90, and after sewing, it apparently expands upward so as to press against the peripheral wall of the needle hole.

As shown in the table, no exudation of the foamed resin from the seams was observed in the headrest obtained in this example.

(4) Comparative Example The thread used in the sewing process was conventional sewing thread (
The procedure was the same as in Example 1 except that the molding step was performed using polyester thread #8). As shown in the table, the headrest obtained in this comparative example contained 250g of 11
In the ffi model, resin leaked from several places on the Il parts, and as the weight of Chonggang became heavier, the number of resin leakage areas increased.
In cases of 2709 and above, resin exudation was observed over the entire circumference of the il'Ju portion.

(Margin below) 0...No leakage Δ・・・Leakage occurs partially ×・・・Leakage occurs around the entire circumference

[Brief explanation of drawings]

1 to 4 relate to an embodiment of the manufacturing method of the present invention, in which FIG. 1 is a sectional view of a sheet material, FIG. Fig. 4 is a perspective view showing the arrangement of the skin material and insert before molding, partially in cross section; Figure 4 is a perspective view showing the arrangement of the skin material in the mold; and Fig. 5 is a main part of the obtained headrest. FIG. FIG. 6 is a front view of the spun yarn used in the example. FIG. 7 is a cross-sectional view of a main part of a molded article showing resin leakage when molded using an 8iyJ product obtained by a conventional sewing method. 1... Sheet material 1'... Skin material 2... Expandable thread 3... Stay 4... Insert
6... Molding mold 7... Inlet 8... Molded object
9... Spun yarn 10... Woven fabric 11.
... Soft foam 12 ... Urethane film

Claims (4)

[Claims] (1) A cutting step of cutting a sheet-like material consisting of a skin body and a fluid shielding layer integrally joined to the back side of the skin body into a predetermined developed shape, and expanding the plurality of cut sheet-like materials. a sewing process in which a bag-shaped skin material is formed by sewing using elastic yarn; an expansion process in which the expandable thread in the sewn portion sewn in the sewing process is expanded at least in the radial direction; While maintaining the expanded state, the skin material is placed in a mold, a foamed resin is injected through the opening of the skin material, and the foaming pressure of the foamed resin is used to press the skin material against the mold surface of the mold. A skin material characterized by comprising: a molding step of molding a molded body filling the inside of the skin material, and a demolding step of opening the mold and taking out the molded body covered with the skin material. A method for producing a foamed resin molded article. (2) The method for manufacturing a foamed resin molded article having a skin material according to claim 1, wherein the expandable thread contains a water-absorbing resin, and the expansion step is carried out by allowing the expandable thread to absorb water. (3) The method for producing a foamed resin molded article having a skin material according to claim 1, wherein the expandable yarn contains a thermally expandable material, and the expansion step is carried out by heating the expandable yarn. (4) The skin material according to claim 1, wherein the expandable yarn is a spun yarn consisting of a base and a cilia, and the expansion step is carried out by raising the cilia of the spun yarn after the sewing step. A method for producing a foamed resin molded article.