JP5634074B2 - Foam molded body, foam molding method thereof, and sheet material for foam molded body - Google Patents

Description

  The present invention relates to a foam molded body in which a sheet material is integrated on the outer surface of a foam molded body, a foam molding method thereof, and a sheet material for the foam molded body.

Foam moldings are often used in parts that come into contact with people, such as chairs and cushions, and especially those that make up vehicle seats are foamed with foaming raw materials such as polyurethane resin and integrated with the sheet material. .
For example, Patent Document 1 discloses a foam formed by attaching a cover sheet to a part of a main body made of a foam material. This cover sheet is composed of a sheet-like substrate made of a fiber and excellent in air permeability, and a thermoplastic resin film laminated on the substrate.

  When the foam is subjected to foam molding, air and generated gas in the mold are exhausted to the outside of the mold through the gas vent hole, and the resin foam in the middle of foaming is blocked by the gas vent sheet and gas. It will not enter the punch hole. This eliminates the occurrence of burrs in the manufactured foam.

JP-A-2-125724

By the way, when foam-molding a foam-molded body, the sheet material (cover sheet, reinforcing material base cloth) is made to follow the molding surface of the molding die without impregnating the foam material into the sheet material, and the desired shape is obtained. In order to obtain a foamed molded article, it is important to adjust the air resistance of how much gas is permeated in the sheet material.
However, in the foam of Patent Document 1, it is only described that the polyethylene film used as the thermoplastic resin film in the cover sheet becomes porous by forming extremely fine holes when laminated on the substrate. . Therefore, it is difficult to adjust the air resistance of the cover sheet of Patent Document 1.

  The present invention has been made in view of such conventional problems, and it is easy to adjust the air resistance of the sheet material, and the sheet material can be molded without impregnating the foam material into the sheet material during foam molding. It is an object of the present invention to provide a foam molded article, a foam molding method thereof, and a sheet material for the foam molded article that can easily follow the molding surface of the molded article and can stably obtain a target shape.

The first invention is a foam molded body in which a sheet material is integrated on the outer surface of the foam molded body main body,
The sheet material is composed of a laminate of a stretched porous film formed by stretching and forming a plurality of pores and a nonwoven fabric , and has a property of allowing gas to permeate but not liquid , and JISP8117. The air resistance according to the Oken type testing machine method is 10 sec / 100 ml or more and 3000 sec / 100 ml or less,
The non-woven fabric side of the sheet material is disposed on the outer surface side of the foam-molded body, and the sheet material and the foam-molded body body are integrated with each other (Claim 1). ).

The second invention is a method of foam-molding a foam-molded body in which a sheet material is integrated on the outer surface of the foam-molded body body using a mold having an upper mold and a lower mold.
Is composed of a laminate of a stretched porous film and nonwoven fabric by performing a stretching process by forming a plurality of holes, one for transmitting gas, liquid have a property of not transmitting, and JISP8117 Oken type tester method A sheet material having an air resistance of 10 sec / 100 ml or more and 3000 sec / 100 ml or less ,
The sheet material is attached to the upper mold in a state where the nonwoven fabric faces the molding surface of the upper mold,
Injecting a foamable resin raw material into the lower mold to close the mold, foaming the foamable resin raw material in a cavity formed between the upper mold and the lower mold,
The sheet material is pushed up by at least one of the foamable resin material itself and the gas pressure generated when the foamable resin material foams, and the gas in the cavity is permeated through the sheet material to the outside of the cavity. Exhaust,
The sheet material is pressed against the molding surface of the upper mold by at least one of the foamable resin material itself and the gas pressure to form the foamed molded body body from the foamable resin material, and the foamed molded body body and in foam molding method of the foamed molded article, which comprises forming a foamed molded by integrating the above sheet material (claim 5).

The third invention is a sheet material for forming a foam molded body integrated with the outer surface of the foam molded body main body,
The sheet material is composed of a laminate of a stretched porous film formed by stretching and forming a plurality of pores and a nonwoven fabric , and has a property of allowing gas to permeate while not allowing liquid to permeate , and JISP8117. The sheet material for a foam molded article is characterized in that the air resistance according to the Oken type tester method is 10 sec / 100 ml or more and 3000 sec / 100 ml or less (claim 7 ).

  In the foamed molded article of the first invention, the sheet material is composed of a laminate of a stretched porous film and a nonwoven fabric formed by stretching to form a plurality of holes. The stretched porous film can easily change the air resistance by a plurality of holes by changing the material of the film before stretching, the processing conditions for stretching, and the like. As a result, the air resistance of the sheet material can be adjusted appropriately, and when the foamed molded product is foam-molded, an appropriate pressure due to the gas generated during foam molding is applied to the sheet material to form the sheet material. While pressing against the molding surface of the mold, this gas can pass through the sheet material and be exhausted outside the cavity of the molding die.

Moreover, since the sheet material has a property of allowing gas to permeate but not liquid, it is possible to prevent the foam material from being impregnated into the sheet material. Therefore, compared to the case where the foamable resin material is impregnated into the sheet material, the amount of the foamable resin material used can be reduced, and the foamed molded product can be reduced in weight.
Therefore, according to the foamed molded product of the first invention, it is easy to adjust the air resistance of the sheet material, and the sheet material is molded into a molding die without impregnating the foamable raw material into the sheet material during foam molding. The surface can be easily followed, and the target shape can be stably obtained.

The foam molding method of the foam molded body of the second invention can easily form a foam molded body of a desired shape by using a sheet material comprising a laminate of the stretched porous film and the nonwoven fabric. Is.
Specifically, the sheet material is attached to the upper mold with the nonwoven fabric facing the molding surface of the upper mold, the foamable resin material is injected into the lower mold, the upper mold is closed, and the upper mold and the lower mold are A foamable resin material is foamed in a cavity formed therebetween. At this time, in the cavity, the sheet material is pushed up by at least one of the foamable resin material itself and the gas pressure generated when the foamable resin material is foamed, and the gas in the cavity passes through the sheet material and passes through the cavity. Exhausted outside. Then, the sheet material is pressed against the molding surface of the upper mold by at least one of the foamable resin material itself and the gas pressure to form the foamed molded body body from the foamable resin material, and the foamed molded body body and the sheet material Are integrated to form a foam molded body.

In addition, the same effects as those of the first invention can be obtained by the foam molding method of the foam molded article of the second invention.
The upper mold in the second invention may be configured by combining an upper mold part and a middle mold part (sometimes called a core or a nest). In this case, the upper mold part and the middle mold part And the upper mold.

The sheet material for a foamed molded article of the third invention is composed of a laminate of a stretched porous film and a nonwoven fabric formed by stretching to form a plurality of holes.
The effect similar to 1st invention can be acquired also by the sheet | seat material for foaming moldings of 3rd invention.

The perspective view which shows the foaming molding in an Example. It is a figure which shows the foaming molding in an Example, and is AA arrow sectional drawing of FIG. The perspective view which shows typically the expanded cross section of the sheet material in an Example. The top view which shows the shaping | molding die in the state in which the upper mold | type in the Example opened. The figure which shows the shaping | molding die in the state in which the upper mold | type in the Example opened, and is sectional drawing equivalent to the BB arrow of FIG. The figure which shows the shaping | molding die in the state which closed the upper mold | type in an Example, and is sectional drawing equivalent to the BB arrow of FIG. Sectional drawing which expands and shows the state which the gas produced when a foamable resin raw material foams in an Example, and the gas in a cavity push up a sheet | seat material toward the molding surface of an upper mold | type, and permeate | transmit a sheet | seat material. Sectional drawing which expands and shows the state in which the sheet material was pressed by the foaming resin raw material itself in the Example by the molding surface of the upper mold | type.

A preferred embodiment of the first to third inventions described above will be described.
1st-3rd invention WHEREIN: The air resistance by the JISP8117 Wangken type test machine method of the said sheet | seat material is 10 sec / 100ml or more and 3000 sec / 100ml or less .
Thereby, when foam-molding a foam-molded body, appropriate air permeability (gas permeability) and liquid impermeability can be imparted to the sheet material.

When the air permeability resistance is less than 10 sec / 100 ml, the air flow rate becomes too large, and it becomes difficult to obtain the effect of lifting the sheet material by the gas generated during foam molding. In addition, the sheet material can easily permeate the foamable resin material, and the sheet material may be impregnated with the foamable resin material. On the other hand, if the air permeability resistance exceeds 3000 sec / 100 ml, the air flow rate of the sheet material is small, and it becomes difficult to exhaust the gas in the cavity of the mold sufficiently to the outside. Air accumulation may occur.
The air resistance of the sheet material is more preferably 50 sec / 100 ml or more and 2500 sec / 100 ml or less. More preferably, it is 100 sec / 100 ml or more and 2000 sec / 100 ml or less.

The foam molded body can be used for a vehicle seat, and the seat is configured by arranging a frame on the back surface of the foam molded body, and the back surface of the foam molded body is formed in a shape corresponding to the frame. In some cases, the sheet material is integrated with the back surface of the foam-molded body and is in contact with the frame (Claims 2 and 8 ).
Also in this case, a sheet material that can prevent the foamable resin material from being impregnated when the foamed molded body is formed is used. Thereby, since the nonwoven fabric of the sheet material and the frame come into contact with each other when the frame is arranged on the back surface of the foam molded article, it is possible to prevent the generation of abnormal noise due to friction between the foamable resin material and the frame.

Moreover, it is preferable that the said sheet | seat material forms the three-dimensional shape (Claim 3 ).
In this case, compared with the case where the sheet material is stitched, the sheet material can be made to better follow the molding surface of the mold during foam molding of the foam molded body. Further, when forming the sheet material into a three-dimensional shape, the sheet materials can be easily integrated without stitching. And in the sheet | seat material, the hole through which the thread | yarn in the case of a stitch | suture is formed is not formed, but generation | occurrence | production of the resin leak from a hole can be prevented.

In the first to third inventions, the plurality of holes in the stretched porous film are formed around the filler by stretching a film in which a resin component is mixed with a filler. Are preferred (claims 4 , 6 , 9 ).
In this case, by blending a resin component with a filler and forming a film, a plurality of holes can be easily formed during the stretching process of the film. Moreover, the size, amount, etc. of the plurality of pores formed in the stretched porous film can be adjusted by adjusting the type, particle size, content, etc. of the filler. Thereby, the adjustment of the air resistance of the sheet material can be facilitated.

Below, the preferable structure of a sheet | seat material and its each part is demonstrated.
(Stretched porous film)
When the stretched porous film is laminated with a non-woven fabric to form a sheet material, the configuration and material thereof are not particularly limited as long as both the air permeability and the liquid impermeability are compatible. The stretched porous film is formed by, for example, blending an inorganic filler such as calcium carbonate, an additive such as a lubricant or an anti-aging agent with a polyolefin-based resin, and stretching the molded film to form an inorganic filler. A plurality of fine holes can be formed by generating voids (holes) around the periphery of the substrate.

  The resin component constituting the stretched porous film is not particularly limited, but polyethylene (low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene), polypropylene (homopolypropylene, random polypropylene) , Various polyolefins such as ethylene-α-olefin copolymer, propylene-α-olefin copolymer, ethylene / propylene / diene terpolymer (EPT or EPDM), ethylene / butene / diene copolymer (EBT), etc. It is preferable to make a system resin a main component (60-100 mass% in the total amount of a resin component). Among them, as a resin component, from the mechanical properties, stretchability, productivity, cost, etc. of the stretched porous film, linear low density polyethylene is the main component (60 to 100% by mass in the total amount of the resin components). It is preferable to do.

  The inorganic filler in the stretched porous film is not particularly limited as long as the film can be made porous by generating voids (pores) around the filler by stretching. For example, talc, silica, stone powder, Zeolite, alumina, aluminum powder, iron powder, metal carbonate of carbonate such as calcium carbonate, magnesium carbonate, magnesium carbonate-calcium, barium carbonate; metal salt of sulfuric acid such as magnesium sulfate, barium sulfate; zinc oxide, titanium oxide, Metal oxides such as magnesium oxide; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, barium hydroxide; magnesium oxide-nickel oxide hydrate, magnesium oxide-zinc oxide Examples include metal hydrates (hydrated metal compounds) such as hydrates. . The shape of the inorganic filler is not particularly limited, and a flat plate shape, a granular shape, and the like can be used. From the viewpoint of forming a void (hole) by stretching, a granular shape (fine particle shape) is preferable. Among these, as the inorganic filler, inorganic fine particles made of calcium carbonate are preferable from the viewpoint of dispersibility when blended with a polyolefin-based resin, cost, and the like.

Although it does not specifically limit as a particle size (average particle diameter) of an inorganic filler (inorganic fine particle), For example, it is preferable that it is 0.1-10 micrometers, More preferably, it is 0.5-5 micrometers. If the particle size of the inorganic filler is less than 0.1 μm, the void formability may be reduced, and if it exceeds 10 μm, the film formation may be broken during stretching and the appearance may be deteriorated.
Although content of an inorganic filler (inorganic fine particle) is not specifically limited, For example, it is preferable that it is 80-200 mass parts with respect to all the resin components (100 mass parts) which comprise a porous film, More preferably Is 100 to 180 parts by mass. When the content of the inorganic filler is within the above range, it becomes easy to adjust the air resistance of the final sheet material to a range of 10 sec / 100 ml to 3000 sec / 100 ml.

In the stretched porous film, various additives such as a colorant, a lubricant, an antioxidant, an antioxidant, an ultraviolet absorber, a flame retardant, and a stabilizer are blended within a range that does not impair the effects of the present invention. May be.
The stretched porous film can be produced by a melt film-forming method (T-die method, inflation method). Of these, the T-die method is preferable. For example, specifically, the above resin component, inorganic filler, and various additives as necessary are mixed and dispersed in a twin-screw kneading extruder, once pelletized, and then in a single-screw extruder. An unstretched film is produced by melting and extruding, and the unstretched film is made porous by stretching it uniaxially or biaxially. When the stretched porous film is a laminated film, it is preferable to use a coextrusion method.

When the stretched porous film is produced, the extrusion temperature is preferably 180 to 250 ° C, more preferably 200 to 250 ° C, and further preferably 210 to 240 ° C. Moreover, 5-25 m / min is preferable for the take-up speed at the time of preparation of an unstretched film, and 5-30 degreeC is preferable for the take-off roll temperature (cooling temperature), More preferably, it is 10-20 degreeC.
As a method of stretching the unstretched film uniaxially or biaxially (sequentially biaxially, simultaneously biaxially), a known and common stretching method such as a roll stretching method or a tenter stretching method can be used. The stretching temperature is preferably 50 to 100 ° C, more preferably 60 to 90 ° C. From the viewpoint of making it porous and stable film formation, the draw ratio in the case of uniaxial stretching is preferably 2 to 5 times, more preferably 3 to 4 times. In the case of biaxial stretching, the draw ratio is preferably 2 to 10 times, more preferably 3 to 7 times.

The pore diameter of the stretched porous film is not particularly limited, but is about 0.05 to 50 μm, and the air resistance of the final sheet material is 10 sec / 100 ml or more and 3000 sec / 100 ml or less. It is preferable from the viewpoint of adjusting to the range and preventing the air accumulation phenomenon during foam molding. Here, the pore diameter of the porous film is measured based on a mercury intrusion method (automatic porosimeter).
The thickness in particular of a stretched porous film is not restrict | limited, For example, 30-150 micrometers is preferable, More preferably, it is 50-120 micrometers.

The stretched porous film preferably has a heat shrinkage (70 ° C., 5 minutes) of from 0 to 3.0% in the longitudinal stretching (MD) direction when measured with the stretched porous film alone. By employing such a stretched porous film, curling (deformation) of the sheet material is prevented, and workability when the sheet material is attached to the upper mold of the mold is improved.
The heat shrinkage rate of the porous film alone is measured and calculated as follows.
First, a marked line is written in the vicinity of the center in the MD direction of a sample cut out to about 200.0 mm (MD) × (CD) about 200.0 mm, read to the first decimal place with a caliper, and further to a dryer at 70 ° C. Add for 5 minutes. Thereafter, the sample is taken out from the dryer and allowed to stand in an atmosphere at 23 ° C. for 30 minutes, and then the same portion is measured with a caliper in the same manner as the beginning, and the shrinkage (%) is calculated by the following equation.
Heat shrinkage in MD direction (%) = ((initial size−size after heating) / initial size) × 100

(Nonwoven fabric)
In the sheet material of the present invention, as the nonwoven fabric laminated with the stretched porous film, when the sheet material is laminated with the stretched porous film, as long as both air permeability and liquid impermeability are compatible, The structure and material are not particularly limited, and it is possible to use a single layer, a multi-layer, a mixed non-woven fabric manufactured from a spunbond method, a spunlace method, a needle punch method, a thermal bond method, a chemical bond method, etc. it can. Further, as the material, nylon-based, polyester-based (PET-based, PBT-based, etc.), polyolefin-based, rayon-based, etc. nonwoven fabrics made of various synthetic fibers, and nonwoven fabrics made of natural fibers can be used. Among these, polyesters are preferable from the viewpoints of adhesiveness, strength, price, workability, and the like.

The nonwoven fabric may have any form of a single layer or multiple layers. In the nonwoven fabric, the fiber diameter, fiber length, basis weight, and the like are not particularly limited. For example, from the viewpoint of processability and cost, the basis weight (basis weight) is preferably about ²⁰ to 100 g / m ² , and more preferably 30. A nonwoven fabric of about ˜80 g / m ² is exemplified. A nonwoven fabric may be comprised only from 1 type of fiber, and may be comprised combining multiple types of fiber.

In particular, by setting the basis weight (basis weight) of the nonwoven fabric to 30 g / m ² or more, the rigidity of the nonwoven fabric is increased, the sheet material after foam molding is less likely to wrinkle, and the appearance quality of the molded product is improved. It is done.
Further, by using a non-woven fabric having a thickness of 0.1 to 1.0 mm (bulky non-woven fabric), a gap is formed between the molding surface of the mold and the stretched porous film. Air can be discharged to the outside. For this reason, the phenomenon of air accumulation during foam molding can be prevented.

As a nonwoven fabric, it is preferable that the heat shrinkage rate (70 degreeC * 5 minutes) at the time of measuring with a nonwoven fabric single-piece | unit is 0% or more and 3.0% or less in MD direction. By employing such a nonwoven fabric, curling as a sheet material is prevented, and workability when the sheet material is attached to the upper mold of the mold is improved. The heat shrinkage rate of the nonwoven fabric alone is also measured by the same method as for the stretched porous film.
In order to make it easy to form a gap between the molding surface of the mold and the stretched porous film, it is preferable to use a nonwoven fabric with fluffed fiber portions.

  The method of laminating the stretched porous film and the nonwoven fabric is not particularly limited, but the laminating means is such that the air resistance as the sheet material after laminating is in the range of 10 sec / 100 ml to 3000 sec / 100 ml. It is necessary to select. Specifically, lamination using an adhesive or a pressure-sensitive adhesive, or lamination means using a heat seal method or a lamination method can be employed.

  The adhesive is not particularly limited, and examples thereof include rubber (natural rubber, styrene elastomer, etc.), urethane (acrylic urethane), acrylic, silicone, polyester, polyamide, epoxy, vinyl alkyl. Known adhesives such as ethers and fluorines can be used. Moreover, an adhesive agent can be used individually or in combination of 2 or more types. Among these, polyamide adhesives and polyester adhesives are particularly preferable.

Further, the adhesive may be an adhesive having any form, and is not particularly limited, but a hot melt type (hot melt type) adhesive is particularly preferably exemplified. In this case, the coating can be performed by melting with heat without using a solvent, and the adhesive layer can be formed by directly applying to a non-woven fabric.
More specifically, the adhesive is preferably a polyamide-based, polyester-based, or polyolefin-based hot-melt adhesive, and more preferably a thermoplastic polyamide-based or polyester-based hot-melt adhesive.
In the present invention, when a polyester-based nonwoven fabric is used as the sheet material nonwoven fabric, a polyamide-based adhesive or a polyester-based adhesive is preferable from the viewpoint of adhesiveness, and a polyamide-based adhesive is particularly preferable. .

The specific method of laminating the stretched porous film and the nonwoven fabric varies depending on the type of adhesive and is not particularly limited. However, when a hot melt adhesive is used, the adhesive is applied on the nonwoven fabric. The method of bonding the stretched porous film is preferably exemplified. As the coating method, a publicly known and commonly used method used as a method for applying a hot melt adhesive can be used, and is not particularly limited. For example, from the viewpoint of maintaining air permeability, spray coating (curtain spray coating) ), Stripe coating, and dot coating are preferred. Among them, a lamination method in which a hot melt type adhesive such as polyamide, polyester, or polyolefin is applied in a fiber form by a curtain spray method, and a stretched porous film and a nonwoven fabric are bonded by a heat bonding roll is preferable. Although the application amount (solid content) of an adhesive agent is not specifically limited, For example, 0.5-20 g / m < ² > is preferable, More preferably, it is 1-8 g / m < ² >.

(Sheet material)
In the present invention, the sheet material composed of a laminate of a stretched porous film and a nonwoven fabric has an elongation at break as the sheet material of 20% or more, preferably 40% or more. By setting the elongation at break of the sheet material to 20% or more, the followability to the unevenness of the mold is improved. The elongation of the sheet material is measured at a tensile speed of 300 mm / min by setting a test piece (25 mm width × 150 mm length) of the sheet material as an inter-chuck distance (100 mm) in an autograph tensile tester.

The sheet material of the present invention preferably has a water pressure resistance of 0.1 to 5.0 kgf / cm ² (9.8 to 490.3 kPa), more preferably 0.5 to 3.0 kgf / cm. ² (49.0 to 294.2 kPa) is desirable. By setting the water pressure resistance of the sheet material within the above range, it is possible to prevent the foamable resin material from being transmitted (passed) through the sheet material.
The water pressure resistance of the sheet material is measured by the B method (high water pressure method) of JIS L1092.

  Further, the heat shrinkage rate (70 ° C., 5 minutes) of the sheet material of the present invention is preferably 3.0% or less in the MD direction, which is excessive in the step of bonding the stretched porous film and the nonwoven fabric. It is important not to apply tension. By using the sheet material of the present invention, curling of the sheet material is prevented, and workability when the sheet material is attached to the upper mold of the mold is improved. The heat shrinkage rate of the sheet material is measured by the same method as for the stretched porous film.

Hereinafter, embodiments of the foam molded article, the foam molding method thereof, and the sheet material for the foam molded article of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the foam molded body 1 of this example is obtained by integrating a sheet material 3 on the outer surface of the foam molded body 2.
As shown in FIG. 3, the sheet material 3 is composed of a laminated body of a stretched porous film 31 that has been stretched to form a plurality of micropores 311, a nonwoven fabric 32, and an adhesive 33, and allows gas to permeate. On the other hand, the liquid does not permeate. The foam molded body 1 is formed such that the nonwoven fabric 32 side of the sheet material 3 is disposed on the outer surface side of the foam molded body 1 and the sheet material 3 and the foam molded body 2 are integrated.

Below, it explains in full detail with reference to FIGS. 1-8 about the foam molding 1 of this example, its foam molding method, and the sheet | seat material 3 for foam molding 1. FIG.
As shown in FIG. 1, the foam molded body 1 of this example is formed by partitioning side portions 12 on the left and right sides of the center portion 11 by a pair of slits 14 provided in the front-rear direction of the surface 101. Further, a rear center portion 13 is defined behind the center portion 11 by slits 15 provided in the left-right direction of the surface 101.
As shown in FIG. 2, a curved protruding portion 111 is formed on the front portion of the back surface 102 of the center portion 11, and on the back surface 102 of the foam molded article 1, The rear side recess 113 in the back surface 102 of the rear center portion 13 is formed along the left-right direction of the foam molded body 1. A convex portion 114 is formed between the concave portions 112 and 113.
1 and 2, the front is indicated by an arrow F, the rear is indicated by an arrow B, the upper is indicated by an arrow U, the lower is indicated by an arrow D, the right is indicated by an arrow R, and the left is indicated by an arrow L. Show.

The foam molded body 1 of this example is used for a seat portion in a vehicle seat. As shown in FIG. 2, the vehicle seat is configured by arranging a metal frame (not shown) on the back surface 102 of the foam molded body 1, and the back surface 102 of the foam molded body 1 has a shape corresponding to the metal frame. Recesses 112 and 113 are formed. The sheet material 3 is integrated with the back surface 102 of the foam molded body 2, and in a state where the foam molded body 1 is attached to the metal frame, the sheet material 3 on the outer surface of the recesses 112 and 113 is the metal frame. It comes to contact.
Here, the frame is a metal frame, but the frame may be a resin frame or the like. Also, the frame is not particularly limited, and may be formed of a pipe, formed of a pipe and a spring, or formed of a sheet metal.

  Since the sheet material 3 of this example has air permeability (gas permeability) and liquid non-permeability, the air resistance according to the JISP 8117 Wangken tester method is 10 sec / 100 ml or more and 3000 sec / 100 ml or less. It is. Moreover, the sheet | seat material 3 can be previously formed in the three-dimensional shape.

As shown in FIG. 3, the plurality of micropores 311 in the stretched porous film 31 are formed around the filler 312 by stretching a film in which the resin component 314 is mixed with the filler 312. In the drawing, the thickness direction of the sheet material 3 is indicated by an arrow T.
The stretched porous film 31 of this example is a film formed by blending an inorganic filler 312 such as calcium carbonate, an additive such as a lubricant and an anti-aging agent with a polyolefin resin 314 serving as a base (matrix). A plurality of micropores 311 are formed by generating voids 313 around the filler 312 by stretching. The plurality of micropores 311 are formed so as to penetrate through the voids 313 existing around the filler 312 while bending in the thickness direction of the stretched porous film 31.

  In addition, the sheet material 3 is formed by applying a hot melt adhesive 33 in a fibrous form by a curtain spray method on a nonwoven fabric 32 and bonding a stretched porous film 31 to the nonwoven fabric 32 from the viewpoint of maintaining air permeability. Yes. A gap through which the gas that has passed through the fine holes 311 of the stretched porous film 31 passes is formed in a portion where the hot melt adhesive 33 is not applied. In addition, the nonwoven fabric 32 is formed from many fibers, and can permeate | transmit both gas and a liquid between fibers. The air resistance of the sheet material 3 is about 60 to 100% of the air resistance of the stretched porous film 31, and the formation state of the plurality of micropores 311 in the stretched porous film 31 (the size of the void 313). And other factors of the sheet material 3).

Next, the manufacturing method and operation effects of the foam molded body 1 of this example will be described.
The foam molded body 1 of the present example in which the sheet material 3 is integrated with the outer surface of the foam molded body 2 is foam-molded using a mold 4 having an upper mold 41 and a lower mold 42.
First, as a sheet material preparation step, it is composed of a laminate of a stretched porous film 31 formed by forming a plurality of micropores 311 by stretching and a nonwoven fabric 32, and has a property of allowing gas to permeate but not liquid to permeate. A sheet material 3 is prepared. At this time, the sheet material 3 may be formed in a three-dimensional shape.

Next, as shown in FIGS. 4 and 5, as a sheet material attaching step, the sheet material 3 is attached to the upper die 41 with the nonwoven fabric 32 facing the molding surface 411 of the upper die 41. At this time, the holding holes 34 provided at a plurality of positions of the sheet material 3 are hooked on holding pins 413 as a holding member attached to the molding surface 411 of the upper die 41 (see FIG. 6), and at a plurality of positions. The provided iron piece (stapler needle, not shown) is attached to the magnet part embedded in the molding surface 411 of the upper die 41 by magnetism. Further, a gas vent 412 is formed in the upper mold 41, and the gas vent 412 is covered with the sheet material 3.
The sheet material 3 is attached to the upper die 41, but may be attached to an intermediate die portion that is provided in the upper die 41 and forms a cavity 43 with the lower die 42.

Next, as a foaming step, the foamable resin raw material 21 is injected into the lower mold 42 from the injection nozzle 45 to close the mold 4, and foamability is generated in the cavity 43 formed between the upper mold 41 and the lower mold 42. The resin raw material 21 is foamed (see FIG. 6). Here, the foamable resin material 21 forms a urethane foam molded article, and is composed of a mixture of a polyol resin material, an isocyanate resin material, a foaming agent, a foam stabilizer, and the like.
Further, the sheet material 3 corresponds to the concave molding surface 46 that forms the convex portion 114 on the rear surface 102 of the foam molded body 1 and the convex molding surface 45 that forms the rear concave portion 113 on the molding surface 411 of the upper mold 41. The portion hangs down slightly, and a gap S is formed between the molding surface 411 (see FIG. 7).

As shown in FIGS. 6 and 7, the foamable resin material 21 injected into the lower mold 42 starts to expand and fills the cavity 43. At this time, the gas G ₁ generated when the foamable resin material 21 is foamed (water vapor, carbon dioxide, etc., and varies depending on the type of foaming agent) and the gas G ₂ (air, etc.) in the cavity 43 are used as the sheet material. 3 is pushed up toward the molding surface 411 of the upper die 41 and penetrates the sheet material 3. The gas pressure generated in the cavity 43 by foaming of the foaming agent is about 0.5 to ¹ kgf / cm ² (68.6 to 98.1 kPa).

The gases G ₁ and G ₂ that have passed through the sheet material 3 pass through the gap S between the molding surface 411 of the upper mold 41 and the sheet material 3, and the gas vent 412 and the upper mold 41 formed in the upper mold 41. The air is exhausted to the outside of the cavity 43 through a parting line 44 between the upper die 42 and the lower die 42.
Further, as shown in FIG. 8, the foamable resin material 21 comes into contact with the sheet material 3, the sheet material 3 is pressed against the molding surface 411 of the upper mold 41 by the foamable resin material 21 itself, and the molding of the upper mold 41 is performed. Gases G ₁ and G ₂ existing in the gap S between the surface 411 and the sheet material 3 are exhausted from the gas vent 412 to the outside of the cavity 43.
In this way, the sheet material 3 is pressed against the molding surface 411 of the upper mold 41 to mold the foam molded body 2 from the foamable resin material 21, and the foam molded body 2 and the sheet 3 are integrated. The foam molded body 1 is formed.

By the way, in order to obtain the foamed molded body 1 having a desired shape by making the sheet material 3 follow the molding surface 411 of the mold 4 when foaming the foamed molded body 1, It is important to adjust the air resistance of the gas G ₁ generated when the conductive resin material 21 is foamed and the flow rate of the gas G ₂ in the cavity 43.
The stretched porous film 31 of the present example can easily change the air resistance due to the plurality of micropores 311 by changing the material of the film before stretching, the processing conditions for stretching, and the like. Therefore, the air permeability resistance of the sheet material 3 can be adjusted appropriately, and when the foam molded body 1 is foam-molded, the force for pushing up the sheet material 3 by the gas pressure and the gas G ₁ that permeates the sheet material 3. And the amount of transmission of G ₂ can be easily adjusted.

Therefore, according to the foam molding method of the foam molded body 1 of this example, it is easy to adjust the air resistance of the sheet material 3, and the sheet material 3 is formed into a convex shape on the molding surface 411 of the upper mold 41 during foam molding. It is possible to easily follow the molding surface 45 and the concave molding surface 46, and it is possible to stably obtain the foam molded body 1 having a desired shape having the rear concave portion 113 and the convex portion 114.
Moreover, since the sheet material 3 has liquid impermeability, the foamable resin material 21 can be prevented from being impregnated into the sheet material 3. Therefore, compared with the case where the foamable resin material 21 is impregnated into the sheet material 3, the amount of the foamable resin material 21 used can be reduced, and the foamed molded body 1 can be reduced in weight. Furthermore, when the foamed molded body 1 is attached to a metal frame, it is possible to prevent the generation of abnormal noise due to friction between the foamable resin material 21 impregnated in the sheet material 3 and the metal frame.

(Confirmation test 1)
In this confirmation test 1, a sheet material (invention products 1 and 2) included in the present invention, a comparative sheet material (comparative product 1), and a non-woven fabric (comparative product 2) are prepared, and their air resistance is reduced. The degree (sec / 100 ml), the water pressure resistance (kPa), the curling property during processing, the resin leakage during foam molding, and the properties of the molded state of the foam molded product were measured, observed, and comprehensively evaluated.
Here, the curling property at the time of processing refers to deformation that occurs when the stretched porous film 31 and the nonwoven fabric 32 are bonded together, and that the curling property is good indicates that the curling property does not occur. Moreover, the resin leakage at the time of foam molding means that the foamable resin raw material 21 permeates the sheet material 3 at the time of foam molding (the foamable resin raw material 21 impregnates the sheet material 3).

(Invention 1)
Inventive product 1 is a sheet material having 400 sec / 100 ml of air permeability resistance (according to JISP 8117 Oken type testing machine method, the same applies hereinafter). Invention product 1 was prepared as follows.
80 parts by weight linear low density polyethylene (density 0.915 g / cm ^3), 60 parts by mass linear low density polyethylene (density 0.903 g / cm ³⁾ a resin (polymer) component, the average particle size of 1. 200 parts by mass of 8 μm calcium carbonate (inorganic fine particles) and 1 part by mass of an antioxidant were melt-kneaded at 180 ° C. to obtain a mixed material. Using this mixed material, it is melt-extruded by the T-die method, and stretched in the longitudinal stretching (MD) direction at a stretching temperature of 80 ° C. and a stretching ratio of 3.5 times by a uniaxial roll stretching method, and has a thickness of 50 μm. A stretched porous film was obtained.
Next, a polyamide hot melt adhesive with a coating amount of 3 g / m ² is applied to a polyester spunbond nonwoven fabric (weight per unit area: 30 g / m ² ) by spray coating, and bonded to the polyethylene-based stretched porous film. Thus, a sheet material of Invention 1 was produced.

(Invention 2)
Invention product 2 is a sheet material having an air resistance of 2000 sec / 100 ml. Invention product 2 was prepared as follows.
80 parts by weight linear low density polyethylene (density 0.915 g / cm ^3), 60 parts by mass linear low density polyethylene (density 0.903 g / cm ³⁾ a resin (polymer) component, the average particle size of 1. 160 parts by mass of 8 μm calcium carbonate (inorganic fine particles) and 1 part by mass of an antioxidant were melt-kneaded at 180 ° C. to obtain a mixed material. Using this mixed material, it is melt-extruded by the T-die method, and stretched in the longitudinal stretching (MD) direction at a stretching temperature of 80 ° C. and a stretching ratio of 3.5 times by a uniaxial roll stretching method, and has a thickness of 50 μm. A stretched porous film was obtained.
Next, a polyamide hot melt adhesive with a coating amount of 3 g / m ² is applied to a polyester spunbond nonwoven fabric (weight per unit area: 30 g / m ² ) by spray coating, and bonded to the polyethylene-based stretched porous film. Thus, a sheet material of Invention 2 was produced.

(Comparative product 1)
Comparative product 1 is a sheet material having an air resistance of 10,000 sec / 100 ml. Comparative product 1 was produced as follows.
80 parts by weight linear low density polyethylene (density 0.915 g / cm ^3), 60 parts by mass linear low density polyethylene (density 0.903 g / cm ³⁾ a resin (polymer) component, the average particle size of 1. 110 parts by mass of 8 μm calcium carbonate (inorganic fine particles) and 1 part by mass of an antioxidant were melt-kneaded at 180 ° C. to obtain a mixed material. Using this mixed material, it is melt-extruded by the T-die method, and stretched in the longitudinal stretching (MD) direction at a stretching temperature of 80 ° C. and a stretching ratio of 3.5 times by a uniaxial roll stretching method, and has a thickness of 50 μm. A stretched porous film was obtained.
Next, a polyamide hot melt adhesive with a coating amount of 3 g / m ² is applied to a polyester spunbond nonwoven fabric (weight per unit area: 30 g / m ² ) by spray coating, and bonded to the polyethylene-based stretched porous film. Thus, a sheet material of Comparative Product 1 was produced.

(Comparative product 2)
Comparative product 2 is made of a nonwoven fabric having a gas resistance of 2 sec / 100 ml.

Table 1 shows the results of each property and comprehensive evaluation for Invention Products 1 and 2 and Comparative Products 1 and 2.

In the table, Inventions 1 and 2 were excellent in the properties of curling at the time of processing, resin leakage at the time of foam molding, and the molded state of the foam molded product, and the overall evaluation was good. On the other hand, with respect to the comparative product 1, molding unevenness (unfilled) due to air accumulation during foam molding occurred in the molded state of the foam molded body, and with the comparative product 2, resin leakage during foam molding occurred. Therefore, the comprehensive evaluation of the comparative products 1 and 2 was deteriorated.
From the above results, the curl properties during processing, the resin leakage during foam molding, and the molded state of the foam molded body are excellent, and the sheet material is made to follow the uneven shape of the molding surface of the molding die, and the desired shape is obtained. In order to obtain a foamed molded article, the air resistance according to the JISP 8117 Oken type tester method is set to 10 sec / 100 ml to 3000 sec / 100 ml, particularly 50 sec / 100 ml to 2500 sec / 100 ml, more preferably 100 sec / 100 ml to 2000 sec. / 100 ml or less was found to be effective.

DESCRIPTION OF SYMBOLS 1 Foam molding 102 Back surface 2 Foam molding main body 21 Foamable resin raw material 3 Sheet material 31 Stretched porous film 311 Micropore 32 Nonwoven fabric 33 Adhesive 4 Molding die 41 Upper die 42 Lower die 43 Cavity S Gap G ₁ , G ₂ gas

Claims (9)

A foam molded body in which a sheet material is integrated on the outer surface of the foam molded body,
The sheet material is composed of a laminate of a stretched porous film formed by stretching and forming a plurality of pores and a nonwoven fabric , and has a property of allowing gas to permeate but not liquid , and JISP8117. The air resistance according to the Oken type testing machine method is 10 sec / 100 ml or more and 3000 sec / 100 ml or less,
A foamed molded product, wherein the nonwoven fabric side of the sheet material is disposed on the outer surface side of the foamed molded product, and the sheet material and the foamed molded product main body are integrated. The foam molded article according to claim 1, wherein the foam molded article is used for a vehicle seat,
  The seat is configured by arranging a frame on the back surface of the foam molded body, and the back surface of the foam molded body is formed in a shape corresponding to the frame,
  The foam molded body, wherein the sheet material is integrated with the back surface of the foam molded body main body and abuts on the frame. 3. The foam molded article according to claim 1, wherein the sheet material forms a three-dimensional shape. The foamed molded product according to any one of claims 1 to 3, wherein the plurality of pores in the stretched porous film is formed by stretching a film in which a filler is blended with a resin component. A foamed molded article formed around the periphery . In the foam molding method in which the foam material in which the sheet material is integrated on the outer surface of the foam molding body, using a molding die having an upper mold and a lower mold,
  It is composed of a laminate of a stretched porous film formed by forming a plurality of pores and a nonwoven fabric, and has a property of allowing gas to permeate but not liquid, and JISP 8117 A sheet material having an air resistance of 10 sec / 100 ml or more and 3000 sec / 100 ml or less,
  The sheet material is attached to the upper mold in a state where the nonwoven fabric faces the molding surface of the upper mold,
  Injecting a foamable resin raw material into the lower mold to close the mold, foaming the foamable resin raw material in a cavity formed between the upper mold and the lower mold,
  The sheet material is pushed up by at least one of the foamable resin material itself and the gas pressure generated when the foamable resin material foams, and the gas in the cavity is permeated through the sheet material to the outside of the cavity. Exhaust,
  The sheet material is pressed against the molding surface of the upper mold by at least one of the foamable resin material itself and the gas pressure to form the foamed molded body body from the foamable resin material, and the foamed molded body body A foam molding method for a foam molded body, wherein the foam molded body is formed by integrating the sheet material and the sheet material. 6. The foam molding method for a foam molded body according to claim 5, wherein the plurality of holes in the stretched porous film are formed around the filler by stretching a film in which a resin component is mixed with a filler. A foam molding method for a foam molded article. A sheet material for forming a foam molded body integrated with the outer surface of the foam molded body main body,
  The sheet material is composed of a laminate of a stretched porous film formed by stretching and forming a plurality of pores and a nonwoven fabric, and has a property of allowing gas to permeate while not allowing liquid to permeate, and JISP8117. A sheet material for a foam-molded article, wherein the air resistance according to the Oken tester method is 10 sec / 100 ml or more and 3000 sec / 100 ml or less. The sheet material for a foam molded article according to claim 7, wherein the foam molded article is used for a vehicle seat,
  The seat is configured by arranging a frame on the back surface of the foam molded body, and the back surface of the foam molded body is formed in a shape corresponding to the frame,
  The sheet material for a foam molded body, wherein the sheet material is integrated with a back surface of the foam molded body main body and abuts on the frame. The sheet material for a foam molded article according to claim 7 or 8, wherein the plurality of holes in the stretched porous film are formed by stretching a film in which a filler is mixed with a resin component, and surrounding the filler. A sheet material for a foam-molded product, characterized in that

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