JP2990208B2 - Urethane foam molding reinforcing material having abnormal noise preventing ability, method for producing the same, and product thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing material for urethane foam molding used for a seat of a vehicle and the like, and a method of manufacturing the same. More particularly, the present invention relates to friction between polyurethane foam and a spring material of a sheet material of a vehicle and the like. TECHNICAL FIELD The present invention relates to a urethane foam molding reinforcing material which prevents generation of rubbing noise, is excellent in silence, and has an excellent reinforcing effect, a method for producing the same, and a vehicle seat obtained by using the same.

[0002]

2. Description of the Related Art As a sheet material for vehicles and the like, a foamed molded article in a flexible polyurethane foam type is mainly used.

In order for such a sheet material to achieve good cushioning properties, in a sheet material structure generally used as shown in FIG.
The layer (B) must be soft, but the next layer (B) should be made of a material having an appropriate bending rigidity or tension (high tensile modulus). It is necessary to have a structure and an action that the cushion action of the spring (C layer) that absorbs and gives a sense of spring is evenly dispersed, and the B layer is kept flat and supported and moves up and down.

[0004] In addition, from the viewpoint of ensuring the durability of such a foamed molded product in a flexible polyurethane foam mold, it is possible to prevent the polyurethane foam from being in contact with a spring (coil-shaped spring) and being rubbed, thereby avoiding damage due to local stress. For,
Conventionally, a reinforcing cloth has been placed on the side of the spring material contacting side of the following polyurethane foam to ensure good cushioning properties and also ensure durability.

[0005] That is, as a typical example, slab urethane and cold gauze are used as reinforcing materials, slab urethane is installed in contact with the foam molding die surface, cold gauze is installed inside the slab urethane, and urethane liquid is injected. Then, a method of producing a foamed product in a flexible polyurethane foam mold in which a reinforcing layer is inserted by heating and pressurizing and foaming has been widely used, and has taken the leading role.

The role of the slab urethane in this method is to impart rigidity to the obtained cushioning material and to prevent clogging of the air vents in the foaming mold due to the inflow of urethane. And the cold gauze is easily embedded and integrated in the polyurethane foam to improve the tensile modulus and form an excellent reinforcing layer.

However, the slab urethane has an insufficient rigidity improving effect, requires much man-hours and is complicated, and it is difficult for the cold cloth, which is a reinforcing cloth, to conform to the cubic curved surface shape of the molded product. was there.

Next, a non-woven fabric (anti-hair wool felt) has been developed for the purpose of eliminating the difficulty of following the shape of the cold gauze and reducing the cost, and taking the leading role.

In order for the 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. It is necessary that the non-woven fabric is embedded in a foaming and expanding polyurethane, and the intersection of the non-woven fabric is recombined with the polyurethane in order to provide a sufficient reinforcing effect and rigidity. The polyurethane foam is filled into the non-woven fabric structure, it needs to have an appropriate rigidity and an appropriate apparent bulk density (porosity) to exhibit high tensile elasticity. It was necessary to make the bonding between the fiber intersections relatively gradual and to have a degree of freedom of tissue deformation.

[0010] From such a viewpoint, nonwoven fabrics having an appropriate bulk density and porosity have been studied and developed and used by trial and error.

The criteria for setting the bulk density and porosity of these reinforcing nonwoven fabrics are that they have a relatively high permeability such that the foaming and expanding polyurethane penetrates over the front surface of the nonwoven fabric and the polyurethane film covers the nonwoven fabric surface. It is selected in consideration of the fact that the permeability is too high and the polyurethane is prevented from flowing into the air vent holes of the molding die.

The mainstream of the reinforcing cloth for foam molding in a flexible polyurethane foam mold has been described above.

However, under a more gradual control, the necessary and sufficient permeability of the polyurethane is secured stably, the inflow of the polyurethane into the air vent of the molding die is completely prevented, and the production is carried out with high yield and high productivity. In order to obtain a reinforcing cloth with good impregnation and permeability of urethane resin, improvement of rigidity and reinforcement, and high integration ability between urethane foam and reinforcing cloth, a reinforcing nonwoven fabric layer with low bulk density and expansion A nonwoven fabric layer having a relatively high bulk density is provided as a barrier layer to block the inflow of polyurethane into the mold air vent hole, and a laminated nonwoven fabric for reinforcement has been developed. -26193).

Furthermore, in order to enhance the reinforcing effect and the effect of closing the air vent hole 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 hole due to the high-weight are increased. In addition, one side of the nonwoven fabric is densified by embossing or the like.
Japanese Patent Application Laid-Open No. 2-258332 discloses a method in which a barrier layer is provided without lamination as disclosed in Japanese Patent Application Laid-Open Publication No. Hei. .

[0015]

With the recent upswing of luxury goods, the functions required for a vehicle seat cushion material are not sufficient if only an excellent cushioning function is satisfied, and are achieved by the prior art. In addition to the functions, it is necessary to satisfy the requirement of environmental functions such as quietness, etc., and it is strongly desired to suppress the generation of abnormal noise such as rubbing noise, bending, refraction noise due to friction between the flexible polyurethane foam foam molded product and the spring material. It came to be.

However, obtained by the prior art,
The foamed molded product in the flexible polyurethane foam mold, which occupies the mainstream at present and is mass-produced by the method described in the above item, has a surface in contact with the spring material covered with a polyurethane film that has passed through a reinforcing cloth. Although the skin layer exerts the reinforcing effect in combination with the reinforcing cloth and satisfies the product function as such, it is necessary to avoid the generation of rubbing noise due to the friction between this polyurethane skin layer and the spring material. There is no.

Furthermore, the improved product obtained according to Japanese Utility Model Publication No. 62-26193 cannot sufficiently satisfy the urethane barrier property only by integrating two layers of nonwoven fabric, and after forming, it generates abnormal noise due to contact with a coil spring or the like. There is a problem that occurs. Further, those disclosed in JP-A-2-258332 also have (1) a basis weight of 110 to 800 g / m ² and a fiber diameter of 1
(2) (1), a foam-forming reinforcing material base fabric having a pressure-bonded layer on one surface side is proposed. In the structure, it is necessary to increase the basis weight of the base fabric in order to satisfy a proper urethane impregnation property and a high urethane barrier property, and there is a problem that the weight of a molded article increases as a result. 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 as compared with (1), but only the single-sided pressure-bonding layer satisfies the high urethane barrier property. In the case of (1), it is necessary to increase the basis weight of the base cloth as in (1), and as a result, there is a problem that the weight of the molded article increases. Furthermore, since a high-density non-woven 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 and bending sound is generated when bending a paper-like material. Is inevitable.

The present invention has been developed in order to solve the above-mentioned problems, namely, the problem of insufficient urethane barrier property, generation of abnormal noise, and increase of the urethane barrier property, which increases the basis weight of the base fabric. In particular, in urethane foam molding of a vehicle seat or the like which requires urethane barrier property strongly due to generation of abnormal noise, strong urethane and base cloth satisfying urethane barrier property, noise prevention and moldability, and after molding. To provide urethane foam molding reinforcement and abnormal noise prevention base fabric for vehicle seats and the like, which has a large urethane reinforcement effect, and a method of manufacturing the same, and a high-performance moldable polyurethane sheet material using the same. It is assumed that.

[0019]

In order to suppress the generation of abnormal noise and to provide an excellent reinforcing effect and excellent workability, the reinforcing material (non-woven fabric) of a foamed molded product in a flexible polyurethane foam mold has a void shown in FIG. It is necessary that the three-layer laminated structure is made of a nonwoven fabric having different rates.

In FIG. 1, 1 denotes a basis weight of 30 to 20.
0 g / m ² , 90-94% porosity, bulky non-woven fabric layer, sufficient basis weight to obtain a strong base and urethane unity, appropriate voids in the layer, and moderate to urethane contact surface It is a non-woven fabric having a soft fuzz. 2 is the basis weight 2
This is a dense nonwoven fabric layer having 0 to 100 g / m ² and a porosity of 87 to 91% and having good urethane barrier properties. The third layer is a nonwoven fabric similar to the first layer and, together with the second layer, contributes to the urethane barrier property and also has a function of preventing generation of abnormal noise due to contact between the urethane layer and a coil spring or the like. And, with the bonding reinforcement layer with polyurethane foam, 4
Is a foam molded article reinforcing material of the present invention in which these three layers are laminated and integrated.

FIG. 2 shows a part of a cross section of a foamed molded article in a flexible polyurethane foam mold produced by using the reinforcing base cloth.

In FIG. 2, reference numeral 1 denotes a bulky nonwoven fabric layer for preventing generation of abnormal noise, and reference numeral 2 denotes a dense reinforcing nonwoven fabric layer containing polyurethane filled with polyurethane foamed and permeated in a foaming mold. Reference numeral 5 is a polyurethane foam layer.

The functions required for such a reinforcing material (non-woven fabric) for foam molding in a flexible polyurethane foam mold having an excellent reinforcing effect in which generation of abnormal noise is suppressed and excellent workability are as follows.

At the time of in-mold foam molding, the urethane resin that expands and expands can be uniformly impregnated and filled, and has a urethane resin permeability enough to allow the urethane foam and the reinforcing material to be tightly integrated. Do not have excessive permeability.

Since the reinforcing material follows the shape of the in-mold foam molded product and retains excellent moldability, the bonding between the fiber intersections of the nonwoven fabric is gently bonded to a tissue structure which is not strong but has flexibility in tissue deformation. Structure

In order to exhibit a sufficient reinforcing effect, the bulk density of the nonwoven fabric must be as high as possible at a level at which the urethane resin can be impregnated and filled during in-mold foam molding.

In order to prevent the generation of rubbing noise on the contact surface with the spring portion and the generation of abnormal noise such as bending noise, the spring does not directly contact the urethane foam and has a relatively low bulk density (relatively high air gap). Rate), it is necessary to have a structure that makes contact with the non-woven fabric, and furthermore, it is necessary to make it an integral structure with reinforced urethane foam.
Reinforcement with relatively low porosity (relatively high bulk density) and urethane resin permeability, woven fabric layer for inflow barrier and nonwoven fabric with relatively low bulk density (relatively high porosity) to prevent noise generation Are required to form an integrated structure in which are laminated.

The permeability of the urethane resin during in-mold foam molding specified in the item is a value determined by the pore size and void ratio (apparent bulk density) of voids in the reinforcing nonwoven fabric, and the void ratio is appropriately selected. By doing so, the polyurethane resin that expands and expands in the foaming mold is contained and filled in the reinforcing material, but it is suppressed to a degree of slight bleeding without a large amount flowing out of the reinforcing non-woven fabric layer (upper surface). It turned out to be possible to control.

Then, as a result of experimentally selecting this appropriate value, it was found that a porosity of 87 to 91% was appropriate.

The porosity (apparent bulk density) is
It is a property highly relevant to the reinforcing performance specified in the paragraph, the higher the bulk density and the shorter the distance between the intersection points of the nonwoven fabric constituent fibers, the more the filling of the polyurethane resin into the nonwoven fabric constituent structure in the dense state during in-mold foam molding And contributes to the increase in rigidity,
In addition, since a high tensile modulus can be obtained by re-adhesion between the intersections of the urethane resin impregnated and impregnated, the apparent bulk is as high as possible at a level at which the urethane resin can be impregnated and filled during in-mold foam molding. It is desirable to select the density, and the reinforcing non-woven fabric is reinforced so that the reinforcing non-woven fabric has a porosity of 87 to 91%, which does not include a contradictory element that meets the criteria for selecting the bulk density (porosity) of the reinforcing base cloth for satisfying the permeability. Performing porosity selection gives good results in all.

By the way, considering the case where the porosity is selected to be larger than 91%, in this case, there occurs a trouble that the expanding polyurethane resin permeates the reinforcing non-woven fabric layer, overflows on the upper surface thereof, and flows into the air vent hole. Or, when the non-woven fabric layer is laminated on the reinforcing cloth, flows into the non-woven fabric layer,
It flows into the nonwoven fabric layer for preventing abnormal noise, and the effect is lost.

Conversely, if the porosity is less than 87%, the reinforcing non-woven fabric layer is less likely to be impregnated with the polyurethane resin, resulting in insufficient bonding between the reinforcing non-woven fabric layer and the polyurethane foam layer.

In order to ensure the molding performance specified in the above item, it is necessary to loosely bond the intersecting points of the reinforcing nonwoven fabric.
Adhesion between the intersections of the constituent fibers of the reinforcing material without affecting the reinforcing effect at all is completed by the urethane resin that penetrates and impregnates during in-mold foam molding, and is completed. It is not necessary to do this in advance.

As a result of an experiment, it is desirable that the nonwoven fabric layer used for the abnormal noise prevention layer is bulky and has cushioning properties, and it is necessary that no abnormal noise is generated at the time of bending. It is clear that a thicker material having a large basis weight and a large basis weight is required, and a material having a basis weight of 30 to 200 g / m ² and a porosity of 90 to 94% may be selected.

Based on the results of such functional analysis, the present invention provides a layer for preventing abnormal noise from having a basis weight of 30 to 200 g / m 2.
A bulky non-woven fabric having a porosity of 90 to 94% in m ² is used as a reinforcing layer and a urethane resin-permeable, inflow barrier layer with a basis weight of 2
A dense nonwoven fabric layer having a porosity of 87 to 91% at 0 to 100 g / m ² is used as a reinforcing layer / polyurethane foam and a reinforcing interlayer bonding reinforcing layer, and has a basis weight of 30 to 200 g / m ^2.
Then, a bulky nonwoven fabric having a porosity of 90 to 94% was applied thereto, and these three layers were laminated and integrated to constitute a laminated urethane foam molding reinforcing material which achieved the intended function.

The nonwoven fabric of the present invention may be a spunbonded nonwoven fabric or a short-fiber nonwoven fabric as long as it satisfies the above conditions, and the constituent fiber material does not need to be limited at all. In addition, heat resistance (low heat shrinkage) that does not cause heat shrinkage during in-mold foam molding is required.

However, it is more preferable to use a spunbonded nonwoven fabric composed of long fibers for the reinforcing nonwoven fabric layer because the reinforcing effect is high.

The predetermined porosity (apparent bulk density)
And a nonwoven fabric laminate obtained by laminating and integrating nonwoven fabrics having different apparent bulk densities (porosity) can be produced by appropriately selecting and combining the following methods.

The apparent bulk density (porosity) of the nonwoven fabric is determined by the denier of the nonwoven fabric fibers, the presence or absence of crimp, the shape of the crimp, the state of adhesion (conditions), the state of entanglement (conditions), and pressing conditions such as calendering. Since it is determined, a nonwoven fabric having a predetermined apparent bulk density can be manufactured by selecting conditions that meet the purpose.

In general, in order to obtain a nonwoven fabric having a high apparent bulk density, it is necessary to use a low-denier fiber, to increase the needle density and to increase the needle depth at the time of confounding by a needle punch, and to apply the temperature and pressure during calendering. Is effective.

Further, in order to manufacture a nonwoven fabric which is laminated to form an integral structure, a. By stacking and needle-punching two (different) webs, a nonwoven web laminated and integrated by mechanical entanglement can be obtained.

This web is commercialized as it is, or impregnated with an adhesive and dried, or is thermally bonded if the web constituting fibers are composed of composite fibers or heat-fusible fibers.

B. It can be manufactured by applying an adhesive to the joining surface of the two webs, laminating and joining.

At this time, the adhesive is applied to the coating of the adhesive solution (emulsion), the interlayer insertion of the hot melt adhesive sheet (nonwoven fabric sheet or film), etc., and the bonding is performed by drying or heat treatment, respectively.

In the case where the nonwoven fabric constituent fiber itself is made of a conjugate fiber or contains a heat-fusible fiber, it is possible to join and integrate by directly heat-treating both laminates.

Next, the present invention will be described in more detail with reference to examples to specifically show embodiments of the present invention.

[0047]

EXAMPLE A non-woven fabric 1 was prepared by spun bonding a web having a random loop structure of 3 denier polyethylene terephthalate fiber produced by the spun bonding method and having a basis weight of 80 g / m ² by calendering with a hot roll at 170 ° C. A web having a random loop structure of 1.5 denier polyethylene terephthalate fiber manufactured by the method and having a basis weight of 40 g / m ² was laminated with a non-woven fabric 2 which was thermocompression-bonded by calendering using a hot roll at 200 ° C. Needle punching is performed using a -40S needle at a needle density of 40 / cm ² and a needle depth of 14 mm, and a nonwoven fabric 3 manufactured under the same manufacturing conditions as the nonwoven fabric 1 is stacked on the nonwoven fabric 2 side of the obtained two-layer laminated nonwoven fabric. Further, a needle using an organ FPD1-40S needle is used. Density 40 / cm ² , needle depth 14m
Then, the nonwoven fabric 4 for reinforcing the molded product shown in FIG.

As a result of the measurement of the nonwoven fabric 2, the porosity of the different sound-preventing nonwoven fabric layers composed of the nonwoven fabrics 1 and 3 in FIG.
The porosity of the reinforcing nonwoven fabric layer composed of 2% and nonwoven fabric 2 is 88
%Met.

The obtained nonwoven fabric 3 for reinforcing a foamed molded product in a polyurethane foam mold is placed in a foaming mold.
With the surface facing the upper surface of the mold, that is, the direction of the air vent hole, the other nonwoven fabric 1 surface is set in the mold with the foamable urethane resin added side, and the foamable urethane resin is added as usual, and the mixture is heated and pressurized. Polyurethane was foamed to form a foamed product in a flexible polyurethane foam mold.

The laminated structure nonwoven fabric 3 in the obtained molded product
In order to check the state of penetration and permeation of the polyurethane resin into the nonwoven fabric 3 and the bonding state between the polyurethane foam layer and the nonwoven fabric 3, the obtained molded article is cut, the state of the cross section is observed, and the polyurethane foam layer and the nonwoven fabric 3 are laminated. The inter-joint strength was studied.

The results of the observation show that the expanded and expanded polyurethane resin permeates and fills the nonwoven fabric 1 and 2 layers evenly, and slightly permeates and fills up to approximately 90% toward the nonwoven fabric 1 side in the two nonwoven fabric layers. As a result, it did not penetrate into one layer of the nonwoven fabric at all, indicating that the target ideal state was achieved.

Further, as for the bonding strength between the polyurethane foam layer and the laminated nonwoven fabric 3, it was shown that the polyurethane foam layer was broken before the boundary surface was peeled off, and sufficient bonding was performed.

Further, in the abnormal noise generation model test in which the nonwoven fabric 1 surface, which is the abnormal noise generation preventing layer, was brought into contact with a coiled spring to repeatedly press and release, no abnormal noise was detected at all. Comparative Example One layer of the reinforcing nonwoven fabric in the example was omitted, and only the nonwoven fabric layers 2 and 3 were formed.
The sample was changed to 3%, and the whole was formed of a nonwoven fabric layer having a porosity of 95%, and a foamed molded article in a flexible polyurethane foam mold was prepared in the same manner as in the example. The permeation and permeation states and the bonding state between the polyurethane foam layer and the laminated nonwoven fabric 3 were observed.

According to the observation results, in the sample having a porosity of 95% as a whole, there is a possibility that the foamed and expanded polyurethane resin partially permeates the nonwoven fabric layer and overflows to the outside, thereby closing the air vent hole of the molding die. This shows that the polyurethane resin reaches the surface layer of the nonwoven fabric and has no noise preventing effect. In the sample in which the porosity of the two nonwoven fabric layers for the reinforcing layer was changed to 83%, the polyurethane resin was added to the two nonwoven fabric layers for the reinforcing layer. There was a place where the penetration and impregnation of the polyurethane foam layer were insufficient, and a place where the bonding between the polyurethane foam layer and the laminated nonwoven fabric 3 was partially insufficient.

The porosity in the present invention is 20 g
² shows the apparent bulk density calculated using the thickness of the nonwoven fabric when a load of / cm ² is applied and the percentage of the effective void volume of the nonwoven fabric calculated from the density of the fibers constituting the nonwoven fabric.

[0056]

The bulky nonwoven fabric layer having a basis weight of 30 to 200 g / m ² and a porosity of 90 to 94% provides an intermediate layer having a basis weight of 20 to 100 g / m ² and a porosity of 87 to 9.
By using a three-layer nonwoven fabric that is sandwiched and laminated with a 1% dense nonwoven fabric layer in the form of a sandwich, and used as a reinforcing material for a foamed product in a flexible polyurethane foam mold,
The ability to prevent abnormal noise is imparted, and the urethane foam molded article is imparted with appropriate rigidity and excellent tensile modulus.

Then, in the production method, in the urethane foam molding, the foamed urethane has a sufficient basis weight to obtain the integrity of the strong reinforcing agent and the urethane, an appropriate space in the layer, and an appropriate surface in contact with the urethane. After passing through a layer having a fluffy layer, the urethane reaches a dense layer having a high urethane barrier property at an early stage, and further blocks urethane that could not be blocked by that layer by completely blocking urethane with the next third layer. , A high urethane barrier property is obtained without compromising moldability with a relatively low base fabric weight, satisfying abnormal noise prevention, and the base fabric and urethane are firmly integrated, that is, urethane having a large urethane reinforcing effect. Enables foam molding. As a product thereof, it is possible to obtain a vehicle seat and the like having excellent cushioning performance based on imparting excellent tensile modulus and good sitting comfort, and excellent durability due to an excellent reinforcing effect.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reinforcing base fabric of the present invention.

FIG. 2 is a cross-sectional view of a foamed molded article in a polyurethane foam mold manufactured using the reinforcing base fabric of the present invention.

FIG. 3 is a cross-sectional view of a foamed molded product in a flexible polyurethane foam mold.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bulk nonwoven layer 2 Dense nonwoven layer 3 Bulk nonwoven layer 4 Reinforcement base fabric for foam molded products 5 Polyurethane foam layer A Polyurethane foam layer B Reinforcement layer C Spring

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B29L 31:58 (72) Inventor Takeshi Inoue 10-24, Toyo-cho, Tsuruga-shi, Fukui Prefecture Toyobo Co., Ltd. Tsuruga Plant (72) Invention Author: Yoshikuni Shioya 982 Kanada, Atsugi-shi, Kanagawa Toyo Sofran Co., Ltd. (72) Inventor Shigeru Inage 982 Kanada, Atsugi-shi, Kanagawa Toyo Sofran Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) B32B 1/00-35/00 B29C 39/00-39/44 B60N 2/00-2/54 A47C 27/00-31/12 D04H 1/00-18/00

Claims (3)

(57) [Claims] 1. A bulky nonwoven fabric layer having a basis weight of 30 to 200 g / m ² and a porosity of 90 to 94% is used as an upper and lower layer, and a dense nonwoven fabric layer having a basis weight of 20 to 100 g / m ² and a porosity of 87 to 91% is used as an intermediate layer. A laminated urethane foam molding reinforcing material characterized by being laminated and integrated as a layer. Upon wherein type in the production of foam moldings, to no porosity 90 in basis weight 30 to 200 g / m ² and a bulky nonwoven fabric layer of 94% and the upper and lower layers, to basis weight 20 100g
/ M ² , a dense nonwoven fabric layer having a porosity of 87 to 91% is laminated and integrated as an intermediate layer, a foamable urethane liquid is supplied to the bulky nonwoven fabric side, and urethane is permeated into the nonwoven fabric layer and foamed. A method for producing a reinforcing material for urethane foam molding, wherein the reinforcing material is integrated with a polyurethane foam to be formed. 3. A dense nonwoven fabric layer having a basis weight of 30 to 200 g / m ² and a porosity of 90 to 94% as upper and lower layers, and a dense nonwoven fabric layer having a basis weight of 20 to 100 g / m ² and a porosity of 87 to 91%. A vehicle seat made of a urethane foam molding reinforcing material laminated and integrated as a layer.