JP3925800B2 - Manufacturing method of sewn integral foam molding - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a sewn integrated foam molded article having a sewn product as a skin, such as a headrest, a seat, and an armrest of an automobile .
[0002]
[Prior art]
For example, a headrest of an automobile has a bag-shaped skin formed by sewing a skin material such as fabric, leather, etc., placed in a foaming mold, and after inserting a stay and a core material, foamed in the bag-shaped skin. It is manufactured by injecting resin and performing foam molding.
[0003]
However, since a needle hole is formed in the outer skin by sewing, if foam molding is performed as it is, the foamed resin leaks from the needle hole, resulting in a defective product. Therefore, for example, Japanese Patent Application Laid-Open No. 2001-246186 describes a method for preventing leakage of foamed resin from a needle hole by using a sewing thread made of a flexible elastic material. In addition, a foam layer made of slab urethane or the like is laminated on the back side of the skin material as a backing material. Since slab urethane and the like have high elasticity, the needle holes in the foam layer are hardly opened by co-sewing the skin material and the foam layer, thereby making it possible to prevent leakage of the foamed resin. Furthermore, when slab urethane is laminated | stacked, shape retention property improves and the setting to a foaming mold becomes easy.
[0004]
By the way, when a foamed resin is injected into a bag-shaped skin to form an integrally molded product, the foamed resin is impregnated and solidified, resulting in a problem that the skin becomes hard and the tactile sensation is impaired. This problem occurs not only when the skin is used alone but also when a skin laminated with slab urethane is used. Generally, slab urethane is manufactured by slicing a foam formed of a material having high air permeability so as to have a predetermined thickness. For this reason, there are many broken bubbles on the surface of the slab urethane, which makes it easy to impregnate the foamed resin.
[0005]
Therefore, slab urethane having a film layer laminated on the surface in contact with the foam molded body is used as a backing material, and impregnation of the foamed resin is prevented by the film layer. Although this film layer can be formed at the time of molding slab urethane, generally, as shown in FIG. 4, the film layer is formed at the time of lamination with the skin material.
[0006]
In this method, first, one surface of slab urethane is flame-treated and heated and melted. After a film is pressure-bonded to one surface of slab urethane using a roller, the other surface of slab urethane is flame-treated and heated and melted. The other surface of the slab urethane is pressure-bonded to the skin material using a roller. According to this method, the lamination of the film and the adhesion to the skin material can be performed continuously, and it is possible to mass-produce the skin in which the adhesive is not required and the impregnation of the foamed resin is prevented.
[0007]
In addition, in JP 2002-240058 A and JP 2002-347043 A, a skin that does not join the skin material and the backing material is described, but in the case of a sewn integral foam molded product having a recess on the surface. There is a problem that the design is impaired due to separation of the skin material from the backing material at the recess. In addition, there is a problem in that sewing becomes unstable because the skin material and the backing material are displaced during sewing. Therefore, it is desirable that the skin material and the backing material are joined to some extent.
[0008]
Japanese Patent Application Laid-Open No. 2002-210271 describes using a closed cell type foam sheet in place of the film layer. If it is a closed cell type foam sheet, even if it is impregnated with the foamed resin, it is only a small part of the surface, so that it is possible to prevent the tactile sensation of the epidermis from being impaired.
[0009]
[Patent Document 1]
JP 2001-246186 [Patent Document 2]
JP 2002-240058 [Patent Document 3]
JP 2002-347043 A [Patent Document 4]
JP2002-210271A [0010]
[Problems to be solved by the invention]
In recent years, leather is often used as a skin material for headrests of luxury cars. In the case of leather, since it cannot be supplied as a continuous body like a fabric, it is difficult to continuously bond slab urethane by frame treatment as described above. In addition, there is a problem that the slab urethane and the leather are not sufficiently joined in the frame processing.
[0011]
Therefore, the slab urethane and the leather are joined using an adhesive, but there is a problem that the film layer forming step and the step of adhering to the leather are required, resulting in a large man-hour.
[0012]
In addition, slab urethane has many air bubbles that are torn on the surface as described above, and is inferior in the touch feeling of a monolithic foamed product obtained by impregnating and solidifying a foamed resin. Then, although the impregnation prevention film is laminated | stacked, there exists a problem that the man-hour becomes large and cost is high.
[0013]
The present invention has been made in view of such circumstances, and can be integrally joined to a skin material such as leather with a small number of man-hours by using a soft backing material that can prevent impregnation of foamed resin and has elasticity. The purpose is to do.
[0014]
[Means for Solving the Problems]
The feature of the method for producing a sewn monolithic foam molded article of the present invention that solves the above problems is a foaming step in which a gas is mixed into a liquid by mechanical foaming to form a mousse,
A drying step of forming a closed cell soft foam-containing body having elasticity by applying and drying the obtained mousse-like liquid on a mold release body,
A shaping step of releasing the soft foam-containing body from the release body into a sheet-like soft foam-containing body ,
A sheet-like soft foam is laminated on the back of the skin material, and the skin material on which the sheet-like soft foam is laminated is sewn into a bag shape to form a bag-like skin having the sheet-like soft foam on the inner surface. Sewing process;
A foam molding step of injecting a liquid foamed resin into the bag-like skin and foam-molding .
[0015]
It is desirable that the liquid body is mousseed by expanding its volume 1.1 to 10 times by bubbles. Further, the liquid material is preferably mousseed by mechanical foaming, and it is desirable to have a urethane resin as a main component.
[0017]
Another feature of the method for producing a sewn integrated foam molded product of the present invention is that a mousse-like liquid material containing innumerable bubbles foamed by mechanical foaming is applied to the back surface of the skin material and dried. And a backing step of laminating a backing material made of a soft foam containing closed cells having elasticity, and a bag-like skin having a backing material on the inner surface by sewing the skin material laminated with the backing material into a bag shape It consists of a sewing process and a foam molding process in which a liquid foam resin is injected into the bag-like skin and foam-molded.
[0018]
In the method for producing a sewn integrated foam molded article of the present invention, a greater effect is exhibited when the skin material is leather.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
In the production method of the present invention , first, gas is mixed into a liquid material by mechanical foaming to form a mousse, and the obtained mousse-like liquid is applied to a mold release and dried to provide a soft soft material having elasticity. Form a foam. The obtained soft foam-containing body contains innumerable independent foams and has flexibility and elasticity comparable to slab urethane.
[0020]
As the liquid, for example, an emulsion or solution of polyethylene, polypropylene, acrylic resin, urethane resin, or the like can be used. Of these, it is desirable to use a urethane resin as a main component. If the urethane resin is the main component, the flexibility as the backing material can be easily controlled as compared with other resins, and the compatibility with the foamed urethane resin generally used as the foamed resin is good and the adhesiveness is excellent.
[0021]
In order to make the liquid material mousse, it can be made mousse by mixing bubbles in the liquid material. When water is used as a solvent, it is also preferable to use an emulsifier such as a surfactant in combination. In order to contain bubbles, bubbles are mixed by a mechanical foaming method such as air loading and stirring in a pressurized state. According to mechanical foaming, bubbles can be mixed stably compared with the chemical foaming method, and the quality of the mousse-like liquid material is stabilized. Moreover, since closed cells are easily formed and film lamination is not necessary, the number of steps can be reduced, and a monolithic foamed product can be manufactured at low cost.
[0022]
The mousse-like liquid material is preferably mousseed by expanding its volume 1.1 to 10 times by bubbles, and more preferably 2 to 8 times mousse-like. If the expansion coefficient is less than 1.1 times, the backing material formed with a low content of air bubbles will have high rigidity, so the feel of the integrally foamed molded product will deteriorate and the weight will become heavier. Decreases. On the other hand, if the expansion coefficient exceeds 10 times, cracks or the like are generated in the formed backing material, and the foamed resin may be impregnated from that portion, so that the tactile sensation of the obtained integrally molded foam product is deteriorated.
[0023]
Examples of the release body include a mold, a release sheet made of fluororesin, or polypropylene. In addition, various coating means such as a bar coater, a brush, and a roller can be used to apply the mousse-like liquid material to the mold release body. For example, a mousse-like liquid material is applied to a mold having a part surface in the shape of a part skin, dried and released to form a sheet-like soft foam containing the same shape as the part skin. Can do. Also , it can be applied to the surface of the release sheet at a predetermined thickness and dried, and if it is released, it can be made into a sheet-like soft foam, and if it is cut into a predetermined shape in the shaping process, A sheet-like soft foam containing the same shape can be formed. In the latter case, it is also possible to continuously produce a sheet-like soft foam.
[0024]
In the method for producing a sewn integrated foam molded article of the present invention , the obtained sheet-like soft foam is laminated on the back surface of the skin material, and the skin material on which the sheet-like soft foam is laminated is sewn into a bag shape. After forming a sheet-like soft foam containing a sheet-like soft foamed body on the inner surface, a liquid foamed resin is injected into the bag-like skin and foam-molded.
[0025]
In this manufacturing method, in the bag-shaped skin, generally, the peripheral portion of the skin material and the sheet-like soft foamed body is co-sewn, and the central portion and the like can be sewn. When the skin material and the sheet-like soft foam are integrally joined, there is a problem that wrinkles are generated on the surface of the sewn product when the foamed molded product formed by expansion of the foamed resin contracts. However, such a problem can be avoided if only the peripheral portion is sewn.
[0026]
And since the impregnation of the foamed resin can be prevented by using the sheet-like soft foam obtained by the production method of the present invention, a monolithic integrated foam molded article excellent in tactile sensation, use feeling and designability is produced. Can do. Moreover, since the process of joining the film for impregnation prevention like the case of using slab urethane becomes unnecessary, productivity improves significantly.
[0027]
However, in the above-described manufacturing method, it is necessary to sew the skin material and the sheet-like soft foamed material in the sewing process, and there is a problem that the skin material and the sheet-like soft foamed material are displaced and difficult to sew. Therefore, in another method for producing a sewn integrated foam molded product of the present invention, a lining process is performed in which a mousse-like liquid material is applied to one surface of the skin material and dried to laminate the backing material. In this way, since the skin material and the backing material are integrally joined, the above-described problem can be avoided.
[0028]
In addition, since the slicing step is not included, a lot of closed cells are present on the surface of the backing material, and a step of bonding a film for preventing impregnation becomes unnecessary. If a mousse-like liquid material made of urethane resin or the like is used, a backing material bonded with high strength to leather or the like can be formed, and no adhesive is required. And since the backing material formed from a liquid material mainly composed of urethane resin has excellent bonding properties with the foamed molded product and the skin material, even when leather is used as the skin material, It is possible to produce a sewn integrated foam molded article having excellent tactile sensation, feeling of use, and design.
[0029]
In this manufacturing method, first, a mousse-like liquid material containing innumerable bubbles is applied to the entire back surface of the skin material and dried . Since the liquid has a mousse shape with countless bubbles and high apparent viscosity, impregnation into the skin material is suppressed, and the skin material is prevented from becoming hard and impairing the touch.
[0030]
In the case of this production method, the mousse-like liquid material is No. in a rotary viscometer. The viscosity (25 ° C.) measured at 6 rpm using 4 rotors is preferably 1000 cps or more. If the viscosity is less than 1000 cps, the skin material is likely to be impregnated, and the touch may be deteriorated.
[0031]
Then, by drying the applied liquid material, a backing material made of a soft foam-containing material having elasticity is formed in a state of being integrally bonded to the skin material. Thereafter, the skin material on which the backing material is laminated is sewn into a bag shape to obtain a bag-like skin material having the backing material on the inner surface, and a liquid foamed resin is injected into the bag-like skin material to perform foam molding. Since the backing material has elasticity, the needle hole at the time of sewing is closed, and leakage of the foamed resin from the needle hole is also prevented.
[0033]
In the lining process, a mousse-like liquid material containing innumerable bubbles is applied to one surface on the back surface of the skin material and dried, thereby laminating a lining material made of a soft foam having elasticity. As the skin material, conventionally used skin materials such as fabric, non-woven fabric, soft polymer sheet, and leather can be used. The thickness of the backing material is not particularly limited, but a thickness of 1 to 3 mm is sufficient in general foam molding. As the coating method, various coating means such as a bar coater, a brush, and a roller can be used.
[0034]
As the mousse-like liquid material, one that has a myriad of bubbles after drying and can form an elastic soft film can be used. Moreover, although what is excellent in bondability with a skin material is desirable, it is also possible to raise joint strength by using an adhesive together depending on the case.
[0035]
As the mousse-like liquid material, the same one as that used in the above-described method for producing the sewn integrated foam molded product can be used. The mousse-like liquid is preferably composed mainly of a urethane resin. If the urethane resin is a main component, the flexibility of the backing material can be easily controlled as compared with other resins, and the compatibility with the foamed urethane resin generally used as the foamed resin is good and the adhesiveness is excellent.
[0036]
In the sewing step, the skin material on which the backing material is laminated is sewn into a bag shape to obtain a bag-like skin material having the backing material on the inner surface. In general, a plurality of part skins are formed by cutting, and after lining the back material on these backs and co-sewing them according to the middle surface so that the skin materials are facing each other, they are reversed and the skin material is outside, the backing material is A bag-like epidermis is formed inside. In this sewing process, the opening of the needle hole is closed by the elasticity of the backing material.
[0037]
In the next foam molding process, a liquid foam resin is injected into the bag-shaped skin and foam-molded. In general, a bag-like skin is inserted into a foaming mold, and by injecting a liquid foamed resin into the bag-like skin and foaming, the bag-like skin is pressed against the mold surface by the expansion force of the foamed resin. A sewn integrated foam molded product having the surface shape precisely transferred is formed.
[0038]
A foamed urethane resin is typically used as the foamed resin, but other resins such as silicone resins and polyolefins may be used as long as they can form a soft and elastic foam molded body. This foamed resin is a low-viscosity liquid at the beginning of the reaction, and is easily impregnated into the backing material and seams of the bag-like skin. However, in the production method of the present invention, a backing material mainly composed of closed cells can be easily formed. Therefore, by using the backing material, impregnation of the foamed resin into the backing material is prevented, and the needle hole is elastic of the backing material. As a result of the opening being closed, the seam is prevented from being impregnated.
[0039]
Therefore, the obtained sewn integral foam molded article is excellent in tactile sensation, and is excellent in design because there is no leakage of the foamed resin. Further, according to the manufacturing method of one sewn integrated foam molded article of the present invention, the skin material is integrally joined to the foam molded body through the backing material, so that wrinkles during use are prevented and the feeling of use is reduced. good. Furthermore, even if it has a concave shape on the surface, its shape design is excellent.
[0040]
【Example】
Hereinafter, the present invention will be described specifically by way of examples.
[0041]
Example 1
Prepare a non-reactive, forced-emulsified urethane resin ("Superflex E-4800", Daiichi Kogyo Seiyaku Co., Ltd., 45% by weight of non-volatile content) and stir in a plastic cup at 950 rpm for 3 minutes to make a mousse A liquid was prepared. This mousse-like liquid has a viscosity (25 ° C) measured at 6 rpm with a No. 4 rotor using a rotary viscometer of 35000 cps, and has a volume three times that of the original urethane resin. ing.
[0042]
This mousse-like liquid material is filled into a box-shaped mold having a cut-out skin-shaped mold surface of the headrest to a thickness of 3 mm, dried at 80 ° C. for 20 minutes, and then heated at 100 ° C. for 10 minutes. And dried . The obtained backing material 2 having a thickness of 2 mm was released from the mold and overlapped with the skin material 1 made of cow leather and cut into the same shape to form the part skin shown in FIG. In this part skin, the skin material 1 and the backing material 2 are not joined. According to the calculation, 30% of the volume of the backing material 2 is occupied by bubbles.
[0043]
A plurality of types of part skins formed in the same manner were aligned with the middle surface so that the skin materials 1 face each other, and the peripheral portions were co-sewn and then inverted to form a bag-shaped skin 3 shown in FIG. Note that, at the bottom of the bag-shaped skin 3, two parts skins overlap to form an unsewn overlapping part 30.
[0044]
Next, as shown in FIG. 3, the bag-shaped skin 3 is placed in the two-part foaming mold 4, and after the core material 5 and the stay 6 are inserted from the overlapping portion 30, a predetermined amount is placed in the bag-shaped skin 3. The foamed urethane resin was injected and the mold was closed to perform foam molding. The bag-like skin 3 is pressed against the mold surface by the expansion pressure of the urethane foam resin, and the part skins on both sides overlap each other and seal at the overlapping portion 30 at the bottom.
[0045]
In the obtained integrally molded foam product, there is no leakage of the urethane foam resin from the seam, and the amount of the urethane resin impregnated into the backing material 2 is small, so that the whole has a uniform and soft feel. It was. Moreover, the mold surface shape of the foaming mold 4 was accurately transferred to the surface of the sewn product, and the design was excellent. Further, although the backing material 2 is integrally joined to the foam molded body 7, the skin material 1 is separated from the backing material 2 except at the peripheral portion, so that even if the foam molded body 7 contracts, the skin material 1. There were no defects that could cause wrinkles on the surface of the material, and the feeling was excellent.
[0046]
(Example 2)
Prepare cow leather, apply the same liquid material as in Example 1 to a thickness of 3 mm on the back with a bar coater, dry at 80 ° C for 20 minutes, and then heat at 100 ° C for 10 minutes to dry. I let you . As a result, a backing material having a thickness of 2 mm was formed on the back surface of the leather. The backing material was a soft layer that was strongly bonded to the leather and had elasticity. Further, the amount of the backing material impregnated into the leather was slight, and the touch of the leather was not impaired. According to the calculation, 30% of the volume of the backing material is occupied by bubbles.
[0047]
Subsequently, the leather on which the backing material was laminated was cut into a predetermined shape to obtain a part skin as shown in FIG. This parts skin has the same configuration as in Example 1 except that the skin material 1 and the backing material 2 are joined. A plurality of types of part skins formed in the same manner were aligned with the middle surface so that the skin materials 1 face each other, and the periphery was sewn and then inverted to form a bag-shaped skin 3 shown in FIG. At the time of sewing, there was no problem that the backing material 2 and the skin material 1 were separated and shifted, and the sewing could be easily performed. Note that, at the bottom of the bag-shaped skin 3, two parts skins overlap to form an unsewn overlapping part 30.
[0048]
Next, as shown in FIG. 3, the bag-shaped skin 3 is placed in the two-part foaming mold 4, and after the core material 5 and the stay 6 are inserted from the overlapping portion 30, a predetermined amount is placed in the bag-shaped skin 3. The foamed urethane resin was injected and the mold was closed to perform foam molding. The bag-like skin 3 is pressed against the mold surface by the expansion pressure of the urethane foam resin, and the part skins on both sides overlap each other and seal at the overlapping portion 30 at the bottom.
[0049]
In the obtained integrally molded foam product, there is no leakage of the urethane foam resin from the seam, and the amount of the urethane resin impregnated into the backing material 2 is small, so that the whole has a uniform and soft feel. It was. Moreover, the mold surface shape of the foaming mold 4 was accurately transferred to the surface of the sewn product, and the design was excellent. Furthermore, since the bag-shaped skin 3 is integrally joined with the foamed molded body 7 via the backing material 2, the shape accuracy of the concave portion is excellent, and there is no problem that wrinkles occur in the bag-shaped skin 3 during use. The use feeling was also excellent.
[0050]
【The invention's effect】
[0051]
According to the method for producing a monolithic integrated foam molded product of the present invention, since a sheet-like soft foam-containing body that is hard to be impregnated with a foam resin is used as a backing material, it has excellent tactile sensation and excellent design without leaking of foam resin. It is possible to manufacture an integrally formed and foamed product at low cost with a small number of man-hours.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a skin layered with a backing material in one embodiment of the present invention.
FIG. 2 is a cross-sectional view of a bag-like skin sewed in an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a foam molding die when foam molding is completed in an embodiment of the present invention.
FIG. 4 is an explanatory view showing a conventional backing process.
[Explanation of symbols]
1: skin material 2: backing material 3: bag-shaped skin 4: foam molding die 5: core material 6: stay 7: foam molding

Claims (5)

A foaming process in which gas is mixed into a liquid material by mechanical foaming to form a mousse,
A drying step of forming a closed cell soft foam-containing body having elasticity by applying and drying the obtained mousse-like liquid on a mold release body,
A shaping step of releasing the soft foam-containing body from the release body to form a sheet-like soft foam-containing body ,
A bag having the sheet-like soft foam on the inner surface by laminating the sheet-like soft foam on the back surface of the skin material and sewing the skin material on which the sheet-like soft foam is laminated into a bag shape Sewing process to form a skin,
And a foam molding step of foam molding by injecting a liquid foam resin into the bag-like skin. 2. The method for producing a sewn integrated foam molded product according to claim 1, wherein in the foaming step, the liquid body expands to a mousse shape by a volume of 1.1 to 10 times due to air bubbles . The method for producing a sewn integrated foam-molded product according to claim 1 or 2, wherein the liquid material contains a urethane resin as a main component . A mousse-like liquid material containing innumerable bubbles foamed by mechanical foaming is applied to the back surface of the skin material and dried to laminate a backing material made of soft, closed-cell foam containing elastic material. Backing process,
A sewing process in which the skin material laminated with the backing material is sewn into a bag shape to form a bag-like skin material having the backing material on the inner surface;
And a foam molding step of foam molding by injecting a liquid foam resin into the bag-like skin. The method for manufacturing a sewn integrated foam-molded product according to claim 1 or 4 , wherein the skin material is leather.

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