JPS6335316A - Production of foamed resin molding having skin material - Google Patents

Abstract

PURPOSE:To make the difference in hardness of the sewed part and other part smaller and to obtain thereby an excellent touch, by sewing the edges of cut sheet-shaped materials inside out and making the seam allowance projected inside to be specified dimension or less. CONSTITUTION:A laminated sheet-shaped material is prepared by adhering a urethane soft foam 2 on the back face side of a nonwoven fabric 1 and a urethane film 3 as a gas barrier layer on the surface of the soft foam. The laminated sheet-shaped material are joined inside out and sewed to form a sewed part 4 and a sewed body is formed with a seam allowance of 7mm or less. This sewed part 4 is placed being faced inside in a mold and a foamable polyurethane resin material mixture of a specific composition is poured in it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a foamed resin molded article in which a skin body made of woven or nonwoven fabric is covered with b skin materials. The present invention is applicable to, for example, automobile headrests, armrests,
It is used to manufacture interior parts such as seats.

[Conventional technology] Conventionally, for example, self! To manufacture headrests and the like used in 1J wide seats, it is common to mold a foam molded product of a predetermined shape from foamed urethane resin, etc., and then cover it with a separately formed bag-shaped skin. be. However, in this manufacturing method, since the molded body and the skin material are separate bodies, there are cases where a gap is created between the two or wrinkles are created on the skin material, which impairs the appearance. Moreover, the coating requires a complicated process such as making it made of N, which requires a large number 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.

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.

[Problem to be Solved by the Invention 1] In a manufacturing method in which a skin material is placed in a mold and the molded body is integrally foamed, the skin material is generally cut into a developed shape and sewn into a bag-like skin. A material is formed and the skin material is placed in a mold. In this sewing process, each cut cloth is sewn with its inner side facing up, so a sewn portion with a seam allowance protruding inward is formed inside the skin material.

When molding using such a skin material, there is a problem in that the sewn portion is impregnated with foamed resin, and the surface hardness of that portion becomes hard, resulting in poor tactility.

This problem is particularly severe in cases where a soft fiTl foam layer is formed on the back side of a skin made of woven fabric or non-woven fabric in order to maintain shape retention performance.

In order to prevent such problems, methods are known that cover the entire sewing area with a film to prevent impregnation with foamed resin, or perform a double stitching process in which the tip of the sewn part is sewn again.

The present invention has been made in view of this problem, and
To provide a manufacturing method that can omit steps such as covering the part with a film or sewing twice, and can prevent the II part from being impregnated with foamed resin, thereby preventing differences in surface hardness. It is something to do.

[Means for Solving the Problems] The method for producing a foamed resin molded article having a skin material according to the present invention comprises at least a cloth material 1a! A $l'lJ process in which the peripheral edge of the cut sheet-like material of the number of paddles is sewn together with the center side to form a sewing part that protrudes inward to form a bag-shaped skin material, and the skin material is placed in a mold. an injection step of injecting foamed resin from the opening of the skin material, and a molded body filling the inside of the skin material while pressing the skin material against the mold surface of the mold by the foaming pressure of the foamed resin. The present invention is characterized by comprising a molding step of molding, and a demolding step of taking out the molded body covered with the skin material by listening to the mold, and having a seam allowance of 7.01 mm or less at the sewing part.

The sheet-like material is composed of at least a cloth material.

For example, a cloth material such as a woven fabric or a non-woven fabric may be used alone, or a combination of polyvinyl chloride, leather, etc. and a cloth material may be used.

It is also preferable that the sheet-like material has a cloth material as the outer skin and a gas shielding layer is provided on the back surface of the outer skin. This can prevent shape defects due to gas passing through the skin during foaming. Here, the gas shielding layer only has to function to press the skin against the mold surface in response to foaming pressure during molding, and does not need to completely shield gas. The gas permeability can be variously selected depending on the foaming pressure. This gas 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 gas shielding layer that has good bonding properties with the foamed resin. For example, when the foamed resin is a urethane resin, the gas shielding layer is preferably formed from a polyurethane film.

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

In the i-manufacturing process, the peripheral edges of a plurality of cut sheet-like materials are sewn to match the inner sides to form sewn portions that protrude inward, thereby forming a bag-shaped skin material.

The biggest feature of this invention is that the seam allowance of this wI part is 7.0.
It is located at 1 m1 or less. That is, as a result of intensive research, the present inventors have discovered that there is a correlation rM relationship between the length of the seam allowance and the surface hardness of the sewn portion, and have completed the present invention. Note that this is due to the fact that the cloth material, soft foam, etc. exposed in the SL parts become hard due to the foamed resin being impregnated and solidified. If the seam allowance of the sewing part is larger than 7.0++s, the surface hardness of that part will become extremely hard, and the difference in hardness from other parts will become large, resulting in a marked decrease in tactility. If the seam allowance is 7.01 or less, the difference is hardly noticeable.

Especially the seam allowance is 3. If it is below Qss, the difference is hardly noticeable and the tactile sensation is significantly improved. By the way, to specify the length of the seam allowance, you can make I so that the seam allowance is 7°O■ or less, or after making Sii, set the seam allowance to 7.3
It is also possible to cut it so that it is below sa. Note that the surface hardness hardly changes depending on the type or thickness of the thread used for sewing, or the sewing pitch, so these can be freely selected and used.

The distance between the sewn portion and the surface is uniquely determined by the type of skin material, cutting shape, foaming pressure, etc., and is not particularly limited as it has little effect on the feel.

In the injection step, the skin material is placed in a mold, and foamed resin is injected through the opening of the skin material. Here, as the foamed resin, conventionally used resins such as polyurethane, polystyrene, polyvinyl chloride, polyethylene, polypropylene, and silicone resin can be used as they are. In addition, the foaming means is the same as conventional methods, such as adding a foaming agent such as fluorocarbon, methylene chloride, or butane, or using a reaction product gas such as carbon dioxide produced by the reaction of water and isocyanate. can do.

In the molding process, the foamed resin is foamed by means such as heating to form a molded body filling the inside of the skin material. If a gas shielding layer is provided inside the skin material, the foaming pressure will be sufficiently transmitted to the skin material, and the skin material will be molded while being pressed against the mold surface.

This allows the skin material to reliably conform to the mold surface and to reliably manufacture a product with a predetermined shape.

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 peripheral edges of a plurality of cut sheet-like materials are sewn to match the inner sides, and a sewn portion protruding inward is formed to form a bag-shaped skin material. be done. Here, the seam allowance of the sewing part is set to be 7.0- or less. Therefore, in the injection process and molding process, the amount of foamed resin impregnated into the sewn part is smaller than the conventional method of impregnating the seam allowance, which reduces the difference between the surface hardness of that part and the surface hardness of other parts. Can be made smaller.

That is, a molded article having a skin material obtained by the manufacturing method of the present invention has a small difference in surface hardness between the sewn portion and other portions, and has an excellent feel to the touch.

[Example] This will be explained in detail below using examples.

(Example 1) As shown in Fig. 1, a 31 m thick urethane soft foam 2 (slab foam) is adhered to the back side of a 11 m thick nonwoven fabric 1, and a A sheet-like material on which a 30 μm thick urethane film 3 as a gas shielding layer was laminated with adhesive was prepared. Then, align this sheet-like material with the inside side facing out, and use polyester thread (#8) and sewing machine needle (#18) to sew 11M sections 4 at a sewing pitch of 2■.
, and take 5 seam allowances (L) from 1 to 10+m to create 5F! A sewn body of type i was formed.

Then, place it in the mold so that the sewn part 4 faces inward, and place the polyether polyol (Sumifen 3063, manufactured by Sumitomo Bayer Urethane Co., Ltd.) in a 80 m1 hanging part, polymer polyol, T-4 (POP31-28, manufactured by Mitsui Toatsu Co., Ltd.). Co., Ltd.) 20 overlapping parts, 4.011 parts of distilled water as a blowing agent, 1 part of triethylenediamine (DABCO33LV, Nippon Nyukazai Co., Ltd. yJ)
．． 5 parts by weight, and silicone surfactant (SRX-2
74C.

(manufactured by Toray Silicone Co., Ltd.) 0.51ml and 11 parts of crude diphenylmethane diisocyanate <44V-
20, manufactured by Sumitomo Bayer Urethane Co., Ltd.) to 7 parts toluene diisocyanate (TDI-80, manufactured by Sumitomo Bayer Urethane Co., Ltd.) in a lff1 ratio of 3 parts, and a curing agent component was mixed so that the ratio by weight was 65:35. A foamed polyurethane resin material mixture was injected.

The mold was then heated to about 40° C. and held for 6 minutes. As a result, the foamed polyurethane resin expanded to about 20 times its volume and was cured. Note that during expansion, the air within the mold was discharged to the outside through a degassing hole (not shown) provided in the mold.

After the foamed polyurethane resin had hardened, the mold was opened and the molded article with the skin material was taken out. Note that the size of this molded body is 300 m5 x 300 ssx 3 Qsm.

The texture of the skin material of the sewn parts of the obtained molded bodies was compared, and the results are shown in the table. In addition, in order to quantify the tactile sensation, the molded body was cut into a size of 50 gv x 50 m5 x 30 mm, the sewn part was compressed from the nonwoven fabric 1 side using an autograph, and the ILD (1 dentation
Load Deflection) was measured. The measurement conditions were as follows: a compression jig with a diameter of 5.11 mm was used, compression ff was 150%, and compression speed was 50IllIl/min. The results are shown in the table.

(Leaving space below) ◎... Soft (no lumps) O... means almost no lumps Δ... some lumps ×... It is clear from the hard side that if the seam allowance is 7.9 mm or less The tactile sensation is within a satisfactory range, and the autograph measurement results also show low values. In particular, if the seam allowance is 3u+ or less, the feel is satisfactory.

(Example 2) In this example, the present invention was applied to the manufacture of a headrest.

(Cutting Step) A sheet material similar to that used in Example 1 was prepared and cut into the desired developed shape of the headrest.

(Sewing process) Next, leave the part that will become the bottom of the headrest and sew these multiple sheets of material together with the inside sides, with a seam allowance of 3.0 mm.
A bag-shaped outer skin material 10 was formed by sewing the bag to form a sewn portion protruding inward.

Then, as shown in FIG. 2, the inserts 12 fixed to the ends of the two stays 11 are inserted into the skin material 10 from the open bottom surface, and the bottom surface is covered with the lid material 13, leaving an opening for resin injection. Covered. Note that this lid material 13 is for preventing leakage of the foamed resin.

(Inhabitant process) The skin material 10 with the insert inserted is placed in the mold together with the lid material 13 so that the injection port 15 of the mold 14 and the frontage of the skin material 10 communicate with each other, as shown in FIG. The mold was tightened. Then, the same foamed polyurethane resin material mixture as used in Example 1 was injected from the injection port 15.

In addition, since the skin material 1o had the soft foam 2, it was placed reliably along the shape of the mold surface within the mold, and had excellent shape retention performance.

(Molding process) Then, the mold 14 was heated to about 40° C. and held for 6 minutes. As a result, the foamed polyurethane resin expanded to about 20 times its volume and was cured. Here, since the urethane film 3 does not allow gas to pass through, the skin material 10 was pressed against the mold surface by the foaming pressure of the foamed polyurethane resin, and in this state, the foamed resin filled the inside of the skin material 10 and hardened. Note that during expansion, the air within the mold 14 was discharged to the outside through a vent hole (not shown) provided in the mold.

(Mold Removal Step) After the foamed polyurethane resin had hardened, the mold was opened, and a headrest consisting of a molded body 16 covered with a skin material 10 was taken out.

In the obtained headrest, as shown in the cross section of the main part in FIG. 4, the molded body 16 was integrally joined to the urethane film 3, and the inside of the skin material was densely filled. There is almost no difference in hardness between the sewing part and other parts,
I was immersed in the sensation of touch.

[Brief explanation of the drawing]

FIG. 1 relates to one embodiment of the manufacturing method of the present invention, and is a sectional view showing a state in which a sheet-like material is sewn. FIGS. 2 to 4 relate to a second embodiment of the manufacturing method of the present invention, and FIG. 2 is a perspective view partially in cross section showing the state of the skin material and insert after the joining process; Figure 3 is a perspective view showing the skin material placed inside the mold, and Figure 4 is 1.
! ? FIG. 1... Non-woven fabric 2... Soft foam 3... Urethane film (gas shielding layer) 4... V & manufacturing part
10... Skin material 11... Stay 12...
Insert 13... Lid material 14... Molding mold 1
5... Inlet 16... Molded object patent applicant
Tokai Kasei Kogyo Co., Ltd. Agent Patent Attorney Okawa
Hirodo Patent Attorney Akio Maruyama Figure 1'$2 Figure

Claims (4)

[Claims] (1) A sewing process of forming a bag-shaped skin material by sewing the peripheral edges of a plurality of cut sheet-like materials made of at least cloth material so as to match the inner sides thereof, and forming a sewn part that protrudes inward; and the skin material. an injection step of placing the material in a mold and injecting foamed resin through the opening of the skin material; and filling the inside of the skin material while pressing the skin material against the mold surface of the mold using the foaming pressure of the foamed resin. The process consists of a molding process of molding a molded body covered with the skin material, and a demolding process of opening the mold and taking out the molded body covered with the skin material. A method for producing a foamed resin molded article having a characteristic skin material. (2) A method for manufacturing a foamed resin molded article having a skin material according to claim 1, wherein the sheet-like material has a gas shielding layer integrally bonded to the surface thereof. (3) The method for manufacturing a foamed resin molded article having a skin material according to claim 2, wherein the foamed resin is a urethane resin and the gas shielding pattern is a urethane film. (4) The method for producing a foamed resin molded article having a skin material according to claim 3, wherein the gas shielding layer is a foam made of closed cells.