JP2004156182A - Reinforcing material for expansion molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing material for expansion molding, highly effective for preventing the squeaking noise generated by the friction between a polyurethane foam and a spring member, having good affinity to the mold for expansion molding and getting excellent reinforcing effect. <P>SOLUTION: The reinforcing material for expansion molding is produced by laminating a flexible nonwoven fabric having a fabric weight of 30-300 g/m<SP>2</SP>and made of a polytrimethylene terephthalate fiber or a polybutylene terephthalate fiber having a 10% elongation stress of 0.2-1 cN/dtex to a dense nonwoven fabric having a fabric weight of 20-200 g/m<SP>2</SP>and an apparent density of 0.08-0.40 g/cm<SP>3</SP>. It is used as a seat material of vehicles to prevent the squeaking noise generated by the friction between the polyurethane foam of the seat material and a spring member. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reinforcing material for foam molding used for a sheet material for a vehicle or the like, and in particular, to prevent generation of rubbing noise generated by friction between a polyurethane foam and a spring material of a sheet material for a vehicle or the like. The present invention relates to a foam molding reinforcing material which is particularly excellent, has good familiarity with a foam molding die, and has an excellent reinforcing effect.
[0002]
[Prior art]
As a sheet material for vehicles and the like, a flexible polyurethane foam in-mold foamed product is mainly used.
[0003]
In order for such a sheet material to achieve good cushioning properties, in a sheet material structure as shown in FIG. 1 which is generally used, the uppermost layer (layer A) in contact with the human body must be soft. The next existing layer (B) should be a material having an appropriate bending rigidity or tension (high tensile elasticity), and a spring (C layer) which receives the B layer and absorbs an impact force to generate a spring feeling. The structure and function of dispersing the cushioning action of the B layer uniformly and moving up and down while keeping the B layer flat are required.
[0004]
Also, from the viewpoint of ensuring the durability of such a foamed molded product in a flexible polyurethane foam mold, in order to prevent the polyurethane foam from being rubbed by the spring (coiled spring) and being rubbed by the local stress, a conventional stress is avoided. A reinforcing cloth is placed on the side of the polyurethane foam contacting the spring material as described below to ensure good cushioning properties and durability.
[0005]
That is, as a typical example,
(1) Using slab urethane and cold gauze as a reinforcing material, slab urethane is installed so as to be in contact with the foam molding die surface, cold gauze is installed inside the slab urethane, and urethane liquid is injected, heated and pressurized to form a reinforcing layer. In many cases, a method for producing a foamed molded article in a flexible polyurethane foam mold into which a flexible polyurethane foam is inserted has been widely used and occupied a leading role.
[0006]
The role of the slab urethane in this method is to provide rigidity to the obtained cushioning material and to prevent clogging of the foaming mold air vent holes due to urethane inflow. It is an object of the present invention to form an excellent reinforcing layer by permeating a cold gauze easily embedded and integrated in a polyurethane foam to improve the tensile modulus.
[0007]
However, the slab urethane has an insufficient rigidity improving effect, and has the disadvantage that the number of steps is large and the work is complicated, and that the cold gauze as a reinforcing cloth is difficult to follow the tertiary curved surface shape of the molded product. .
[0008]
{Circle around (2)} A nonwoven fabric (anti-hair wool felt) has been developed for the purpose of resolving the difficulty of being difficult to follow the shape of the cold gauze and reducing costs and taking the lead.
[0009]
In order for this nonwoven fabric to satisfy the required properties as a reinforcing cloth, it is necessary that the nonwoven fabric has an appropriate permeability for the urethane liquid that expands and expands, and for this purpose, it has a pore size and an apparent density of an appropriate pore size. In order to provide sufficient reinforcing effect and rigidity, the non-woven fabric is embedded in the foaming and expanding polyurethane, the non-woven fabric intersection is recombined with the polyurethane, and the polyurethane foam is formed in the non-woven fabric structure. Filling requires moderate rigidity and moderate apparent density to exhibit high tensile modulus.Furthermore, in order to ensure adaptability to the curved surface shape of the molded product, bonding between the nonwoven fabric constituent fiber intersections is performed relatively gently, resulting in structural deformation. It was necessary to have a degree of freedom.
[0010]
From such a viewpoint, a nonwoven fabric having an appropriate apparent density has been studied and developed and used by trial and error.
[0011]
The standard for setting the apparent density of these reinforcing nonwoven fabrics is selected so that the polyurethane that expands and expands has a relatively high permeability so that the polyurethane film penetrates over the front surface of the nonwoven fabric and the polyurethane film covers the nonwoven fabric surface. It is selected in consideration of suppressing the polyurethane to a level at which the polyurethane does not flow into the air vent holes of the molding die.
[0012]
The above is the mainstream of the reinforcing cloth for foam molding in a flexible polyurethane foam mold.
[0013]
(3) However, under a more gradual control, stable and sufficient permeability of polyurethane is ensured, polyurethane is completely prevented from flowing into the air vent of the molding die, and production is performed with high yield and high productivity. To improve the impregnation and permeability of urethane resin, improve rigidity and reinforcement, and obtain a reinforcing cloth with high integration ability between urethane foam and reinforcing cloth, a reinforcing nonwoven fabric layer with low apparent density and expansion In order to block the inflow of the incoming polyurethane into the mold air vent holes, a nonwoven fabric layer having a relatively high apparent density is provided as a barrier layer, and a laminated nonwoven fabric for reinforcement has been developed (for example, Patent Document 1).
[0014]
[Patent Document 1]
JP-B-62-26193 [0015]
(4) Furthermore, in order to enhance the reinforcing effect and the effect of preventing the closing of air vent holes due to the inflow of polyurethane, a high-weight nonwoven fabric is used as a reinforcing base cloth, and the high reinforcing effect and the inflow of polyurethane into the air vent holes due to the high-weight are prevented. And a method for preventing the same, and further increasing the density of one surface of the nonwoven fabric with embossing by embossing or the like, and providing a blocking layer as disclosed in Japanese Utility Model Publication No. Sho 62-26193 without laminating the polyurethane air vent hole. A method of more reliably preventing the inflow of water into the air has been invented and developed (for example, see Patent Document 2).
[0016]
[Patent Document 2]
JP-A-2-258332
[Problems to be solved by the invention]
With the recent rise of high-grade products, the functions required for vehicle seat cushions are not sufficient if only excellent cushioning functions are satisfied. In addition to the functions achieved by conventional technologies, environmental functions such as quietness It is necessary to satisfy the requirement of satisfaction, and it has been strongly desired to suppress generation of abnormal noise such as rubbing noise, bending, and bending noise due to friction between a flexible polyurethane foam foam molded product and a spring material.
[0018]
However, the flexible polyurethane foam-in-foam molded product occupying the mainstream at present and being mass-produced by the methods described in the above items (1) and (2) obtained by the prior art is characterized in that the surface in contact with the spring material has a reinforcing cloth. It is covered with a polyurethane film that has passed through the polyurethane skin layer, and this polyurethane skin layer exhibits a reinforcing effect in combination with the reinforcing cloth, and satisfies the product function as it is. The generation of rubbing noise due to friction with the material is inevitable.
[0019]
Furthermore, the improved product obtained by Japanese Utility Model Publication No. 62-26193 also fails to sufficiently satisfy the urethane barrier property by simply integrating two layers of nonwoven fabric, and generates abnormal noise due to contact with a coil spring or the like after molding. There's a problem. Japanese Patent Application Laid-Open No. 2-258332 also discloses 1) a foam-forming reinforcing material base fabric made of a high-weight nonwoven fabric having a basis weight of 110 to 800 g / m ² and a fiber diameter of 1 to 16 d, and 2) one surface of 1). A reinforcing fabric base for foam molding having a pressure-bonded layer on the side has been proposed, but in the structure of 1), it is necessary to increase the basis weight of the base fabric in order to satisfy appropriate urethane impregnation and high urethane barrier properties. As a result, there is a problem that the weight of the molded article increases. In the structure of 2), by having the pressure-bonding layer, the urethane barrier property is superior to that of 1) under the same weight, but it is necessary to satisfy the high urethane-blocking property only by the single-sided pressure-bonding layer. As in the case of (1), the basis weight of the base cloth must be increased, and as a result, there is a problem that the weight of the molded article increases. Furthermore, since a high-density nonwoven fabric layer that blocks polyurethane flowing out is present in the outermost layer and is in contact with the spring material, an abnormal noise called bending (bending / refraction sound) is generated when the paper-like material is bent. Is inevitable.
[0020]
The present invention, in order to solve the problems described above, namely, insufficient urethane blocking properties, the problem of increasing the noise generation and urethane blocking properties, the basis weight of the base fabric also increases, urethane foam molding, particularly, When urethane foam molding of vehicle seats, etc., which require strong urethane barrier property due to generation of abnormal noise, it is satisfied with urethane barrier property, noise prevention and moldability, and integrated with strong urethane and base cloth after molding. An object of the present invention is to provide a foam-forming reinforcing material having an anti-noise property, such as a vehicular sheet or the like, having a large reinforcing effect of urethane, which imparts a property of enhancing urethane.
[0021]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems. That is,
(1) and the basis weight 30~300g / ^{m 2} flexible nonwoven fabric comprising 10% fiber elongation when the stress 0.2~1cN / dtex, apparent density in weight per unit area 20~200g / ^{m 2} 0.08~0.40g / cm ^And a dense nonwoven fabric according to item ^{3 above} ,
(2) The reinforcing material for foam molding according to (1), wherein the flexible nonwoven fabric is laminated on one surface of a dense nonwoven fabric.
(3) The reinforcing material for foam molding according to (1), wherein the flexible nonwoven fabric is laminated on both sides of a dense nonwoven fabric.
(4) The foam-molding reinforcing material according to any one of (1) to (3), wherein at least a fiber constituting the flexible nonwoven fabric is a polytrimethylene terephthalate fiber or a polybutylene terephthalate fiber.
(5) The foam molding reinforcing material according to (1), which is disposed on a sheet material for a vehicle or the like, wherein the foam molding reinforcing material for preventing generation of rubbing noise is provided.
It is.
[0022]
Hereinafter, the present invention will be described in detail.
First, the function required for the foam molding reinforcing material of the present invention,
(1) The urethane resin, which expands and expands during the in-mold foam molding, can be impregnated and filled uniformly, and has a urethane resin permeability enough to allow the urethane foam and the reinforcing material to be tightly integrated. Not having excessive permeability;
[0023]
(2) Since the reinforcing material follows the shape of the in-mold foam molded product and retains excellent moldability, the bonding between the non-woven fabric constituent fiber intersections is not strong but has a gradual tissue structure with flexibility in tissue deformation. Being a bonded structure,
[0024]
(3) In order to exhibit a sufficient reinforcing effect, the apparent density of the nonwoven fabric should be as high as possible at a level at which urethane resin impregnation and filling can be performed during in-mold foam molding.
[0025]
(4) In order to prevent the generation of rubbing noise on the contact surface with the spring part and the generation of abnormal noise such as bending noise, a structure is required in which the spring does not directly contact the urethane foam but contacts the flexible non-woven fabric. In addition, since it is necessary to form an integral structure with the reinforced urethane foam, the reinforcing cloth is made of a nonwoven fabric for reinforcing having a relatively high apparent density having functions of (1), (2), and (3). It is required that a nonwoven fabric is laminated on one side or both sides to form an integrated structure.
[0026]
The permeability of the urethane resin at the time of in-mold foam molding specified in item (1) is a value determined by the pore size and apparent density of the voids in the reinforcing nonwoven fabric. The polyurethane resin, which expands and expands in the molding die, is contained and filled in the reinforcing material, but is controlled to be slightly exuded without flowing out in large amounts outside (upper surface) of the reinforcing nonwoven fabric layer. It turns out that it is possible.
[0027]
Therefore, as a result of experimentally selecting this appropriate value, it was found that an apparent density of 0.08 to 0.40 g / cm ³ was appropriate.
[0028]
The apparent density is a property that is highly relevant to the reinforcing performance specified in item (3). The higher the apparent density and the shorter the distance between the nonwoven fabric constituent fiber intersections, the more the apparent density in the nonwoven fabric structure during in-mold foam molding is increased. The polyurethane resin is filled in a dense state, which contributes to the increase in rigidity, and also enables a high value of the tensile modulus of elasticity due to re-adhesion between the intersections by the urethane resin impregnated and impregnated. Urethane resin impregnation at the time of foam molding, it is desirable to select the highest possible apparent density at a level that can be filled, it does not include elements that conflict with the reinforcing cloth apparent density selection criteria to satisfy permeability, Selection of the apparent density of the reinforcing nonwoven fabric so as to have an apparent density of 0.08 to 0.40 g / cm ³ gives good results in all cases.
[0029]
By the way, considering the case where the apparent density selection is smaller than 0.08 g / cm ³ , in this case, a problem occurs in which the expanding polyurethane resin permeates the reinforcing nonwoven fabric layer, overflows on the upper surface thereof, and flows into the air vent hole. Alternatively, when the nonwoven fabric layer is laminated on the reinforcing fabric, the nonwoven fabric layer flows into the nonwoven fabric layer, flows into the nonwoven fabric layer for preventing abnormal noise, and the effect is lost.
[0030]
Conversely, when the apparent density is selected to be greater than 0.40 g / cm ³ , the reinforcing nonwoven fabric layer is less likely to be impregnated with the polyurethane resin, resulting in insufficient bonding between the reinforcing nonwoven fabric layer and the polyurethane foam layer.
[0031]
In order to secure the molding performance specified in the item (2), the gradual adhesion between the intersections of the reinforcing nonwoven fabric does not affect the reinforcing effect at all. The final bonding is performed and completed by the urethane resin penetrating and impregnating at the time of molding, so that it is not necessary to perform strong bonding that hinders the molding performance in advance.
[0032]
As a result of an experiment, the nonwoven fabric layer used for the abnormal noise prevention layer is preferably made of fibers having a stress at 10% elongation of 0.2 to 1 cN / dtex, and is preferably bulky and cushioned, and generates abnormal noise when bent. It is necessary to use a material having a large basis weight and a large thickness, and it is clear that a material having a basis weight of 30 to 300 g / m ² may be selected.
[0033]
The nonwoven fabric of the present invention may be either a long-fiber nonwoven fabric or a short-fiber nonwoven fabric as long as the above conditions are satisfied. The constituent fiber material is not particularly limited as long as the fiber material has a stress at 10% elongation within the range of 0.2 to 1 cN / dtex. Properties (low heat shrinkage) are required, and examples thereof include polytrimethylene terephthalate, polybutylene terephthalate, polyetherester copolymer, copolymerized polyester obtained by copolymerizing isophthalic acid, and nylon. Further, there is no reason to be limited to a single-component system, and a multi-component system such as a core-sheath type, an eccentric core-sheath type, a side-by-side type, and a sea-island type may be used, and there is no particular limitation on the shape of the fiber cross section. . If necessary, various additives such as a matting agent, a pigment, an antioxidant, an ultraviolet absorber, a light stabilizer, a crystal nucleating agent, and a flame retardant can be used in combination.
[0034]
However, application of a long-fiber nonwoven fabric to the nonwoven fabric layer for reinforcement has a high reinforcing effect and is more preferable.
[0035]
A nonwoven fabric laminate having these predetermined apparent densities and laminated and integrated with nonwoven fabrics having different apparent densities can be manufactured by appropriately selecting and combining the following methods.
[0036]
The apparent density of the nonwoven fabric is determined by the fineness of the constituent fibers of the nonwoven fabric, the presence or absence of crimp, the shape of the crimp, the state of adhesion (conditions), the state of confounding (conditions), the pressing conditions such as calendering, etc. By selecting such conditions, a nonwoven fabric having a predetermined apparent density can be manufactured.
[0037]
In general, in order to obtain a nonwoven fabric with a high apparent density, use fibers with low fineness, increase the needle density and increase the needle depth when entangled with a needle punch, increase the temperature and pressure in calendering, etc. Is valid.
[0038]
Also, in order to manufacture a nonwoven fabric that is laminated and has an integrated structure,
1) By stacking and needle-punching two or three types of webs, a nonwoven web laminated and integrated by mechanical entanglement can be obtained.
[0039]
This web is commercialized as it is or by impregnating and drying an adhesive, or is thermally bonded if the web constituting fibers are composed of composite fibers or heat-fusible fibers.
[0040]
2) Two or three types of webs can be manufactured by applying an adhesive to a bonding surface, laminating and bonding.
[0041]
At this time, the adhesive is applied by applying an adhesive solution (emulsion), inserting a hot-melt adhesive sheet (nonwoven fabric sheet or film) into layers, and drying or heat-treating to bond.
[0042]
When the constituent fibers of the nonwoven fabric are made of composite fibers or include heat-fusible fibers, lamination and integration can be performed by directly heat-treating two or three types of webs.
[0043]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The evaluation methods used in Examples and Comparative Examples of the present invention are as follows.
(1) Intrinsic viscosity [dl / g] of polytrimethylene terephthalate
Using a mixed solution of p-chlorophenol and tetrachloroethane (3: 1 mass ratio) as a solvent, 0.1 g of a sample was dissolved in 25 ml of the solvent, and the measurement was performed by a conventional method at a temperature of 30 ° C.
(2) Intrinsic viscosity of polyethylene terephthalate [dl / g]
Using a mixed solution of phenol and tetrachloroethane (6: 4 mass ratio) as a solvent, 0.1 g of a sample was dissolved in 25 ml of the solvent, and the measurement was carried out by a conventional method at a temperature of 30 ° C.
(3) Fineness [dtex]
Using a scanning electron microscope photograph, the fiber diameter was measured at n = 20, and the fiber diameter was determined by performing density correction.
(4) Weight [g / m ² ]
It was measured in accordance with JIS L 1906 “Mass per unit area”.
(5) Thickness [mm]
It was measured under a load of 20 gf / cm ² in accordance with JIS L 1906 “Thickness”.
(6) Apparent density [g / cm ³ ]
It was calculated from the basis weight and thickness measured in the above (4) and (5) using the following formula.
Apparent density = weight ÷ (thickness x 10 ³ )
(7) Stress at 10% Elongation Stress at 10% elongation was measured in accordance with JIS L 1015 “tensile strength and elongation”, and calculated by dividing by the fineness measured in (3) above.
[0044]
Example 1
Polytrimethylene terephthalate having an intrinsic viscosity of 0.91 is spun, cooled, stretched, spread, and collected by a spun bond method, and is composed of long fibers having a fineness of 3.3 dtex and a stress at the time of 10% elongation of 0.73 cN / dtex. Nonwoven fabric 1 obtained by thermocompression bonding a web having a basis weight of 80 g / m ^{2 at} a temperature of 120 ° C. and a linear pressure of 30 kgf / cm with a hot embossing roll, and a stress at 10% elongation at a fineness of 2.2 dtex and a fineness of 2.2 dtex. Is a nonwoven fabric 2 having an apparent density of 0.4 g / m ² made of a polytrimethylene terephthalate long fiber of 0.65 cN / dtex and thermocompressed with a hot embossing roll at a temperature of 150 ° C. and a linear pressure of 40 kgf / cm. 21g / cm ³⁾ and was laminated, needle density 40 Quai / cm ² by using a needle organ Co. FPD1-40S, needle And needle punching in degrees 14 mm, to obtain a two-layer laminated structure nonwoven fabric.
[0045]
Example 2
The nonwoven fabric 1 is overlaid on the nonwoven fabric 2 side of the two-layer laminated nonwoven fabric obtained in Example 1, and further needle-punched with a needle of FPD1-40S manufactured by Organ Co. at a needle density of 40 / cm ² and a needle depth of 14 mm, A three-layer nonwoven fabric was obtained.
[0046]
Example 3
A nonwoven fabric 1 similar to that of Example 1 and polyethylene terephthalate having an intrinsic viscosity of 0.63 were spun, cooled, drawn, spread, and collected by a spun bond method, and the stress at the time of 10% elongation at a fineness of 2.2 dtex was 1. Nonwoven fabric 3 (appearance density: 0.16 g / cm ³ ) obtained by thermocompression bonding a web having a basis weight of 40 g / m ² composed of polyethylene terephthalate long fibers of 37 cN / dtex with a hot embossing roll at a temperature of 200 ° C. and a linear pressure of 40 kgf / cm. Were needle-punched with a needle of FPD1-40S manufactured by Organ Corporation at a needle density of 40 / cm ² and a needle depth of 14 mm to obtain a two-layer nonwoven fabric.
[0047]
Example 4
The nonwoven fabric 1 is overlaid on the nonwoven fabric 3 surface side of the two-layer laminated nonwoven fabric obtained in Example 3, and further needle-punched with a needle of FPD1-40S manufactured by Organ Co. at a needle density of 40 / cm ² and a needle depth of 14 mm, A three-layer nonwoven fabric was obtained.
[0048]
Comparative Example 1
Polyethylene terephthalate having an intrinsic viscosity of 0.63 is spun, cooled, drawn, spread, and collected by a spun bond method, and is composed of polyethylene terephthalate long fiber having a fineness of 3.3 dtex and a stress at the time of 10% elongation of 1.14 cN / dtex. A nonwoven fabric 4 obtained by thermocompression bonding a web having a basis weight of 80 g / m ^{2 with} a hot embossing roll at a temperature of 170 ° C. and a linear pressure of 30 kgf / cm, and a nonwoven fabric 2 similar to that of Example 1 are laminated. Needle punching was performed using a 40S needle at a needle density of 40 / cm ² and a needle depth of 14 mm to obtain a two-layer laminated nonwoven fabric.
[0049]
Comparative Example 2
The nonwoven fabric 4 is overlaid on the nonwoven fabric 2 surface side of the two-layer laminated nonwoven fabric obtained in Comparative Example 1, and further needle-punched with a needle of FPD1-40S manufactured by Organ Co. at a needle density of 40 / cm ² and a needle depth of 14 mm, A three-layer nonwoven fabric was obtained.
[0050]
The laminated nonwoven fabric obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were set in a mold for foam molding, a foamable urethane resin was added as usual, and foaming of polyurethane was performed under heating and pressure. Was carried out to produce a foamed molded article in a flexible polyurethane foam mold. Here, in Examples 1 and 3, the nonwoven fabric 1 was set, and in Comparative Example 1, the nonwoven fabric 4 was set on the coiled spring side.
[0051]
In Examples 1 to 4, there was no generation of abnormal noise due to repeated pressurization and depressurization in contact with the coiled spring, the mold was well adapted, and the foaming urethane resin did not exude.
[0052]
On the other hand, in Comparative Examples 1 and 2, although familiarity with the mold was good, and there was no oozing of the foamable urethane resin, generation of abnormal noise due to repeated pressurization and depressurization in contact with the coiled spring was observed. Somewhat recognized.
[0053]
【The invention's effect】
According to the reinforcing material for foam molding of the present invention, since the flexible nonwoven fabric is used on the coiled spring side, it is excellent in preventing the generation of rubbing noise caused by friction between the polyurethane foam and the spring material, and also in the foam molding. It has good familiarity with molds for use, and an excellent reinforcing effect can be obtained.
[Brief description of the drawings]
FIG. 1 is a sectional view of a foamed molded product in a flexible polyurethane foam mold.
[Explanation of symbols]
1 Polyurethane foam layer 2 Reinforcement layer 3 Spring (coil spring)

Claims (5)

A basis weight 30~300g / ^{m 2} of a flexible nonwoven fabric at 10% elongation stress is made of fibers of 0.2~1cN / dtex, density 0.08~0.40g / cm ³ apparent in basis weight 20 to 200 g / ^{m 2} A reinforcing material for foam molding, comprising a dense nonwoven fabric. The reinforcing material for foam molding according to claim 1, wherein the flexible nonwoven fabric is laminated on one surface of the dense nonwoven fabric. The reinforcing material for foam molding according to claim 1, wherein the flexible nonwoven fabric is laminated on both sides of the dense nonwoven fabric. The reinforcing material for foam molding according to any one of claims 1 to 3, wherein at least a fiber constituting the flexible nonwoven fabric is a polytrimethylene terephthalate fiber or a polybutylene terephthalate fiber. A foam molding reinforcing material for preventing occurrence of rubbing noise, wherein the foam molding reinforcing material according to claim 1 is disposed on a sheet material for a vehicle or the like.

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