JPH06171002A - Reinforcing base fabric for urethane foam molding, production thereof and product - Google Patents

Abstract

PURPOSE:To prevent the lowering of rigidity of a urethane foam molded product and the generation of the unpleasant sound thereof by using a reinforcing base fabric for a soft polyurethane foam in-mold foamed molded product obtained by integrally laminating two kinds of nonwoven fabrics specified in wt. basis and voids. CONSTITUTION:A bulky nonwoven fabric layer 1 with a wt. basis of 30-300g/m<2> and voids of 90-94% contributes to urethane barrier properties. A dense nonwoven fabric layer 2 with a wt. basis of 20-100g/m<2> and voids of 87-91% has proper voids in order to obtain proper fluffing on the contact surface with foamed urethane and proper impregnation properties and barrier properties therein and contributes to the compatibility of impregnation function and barrier properties. Both layers are integrally laminated to form a reinforcing base fabric 3 for a foamed molded product.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing base fabric for urethane foam molding and a method for producing the same, and more particularly, to prevent a decrease in rigidity of a seat cushion member of a vehicle or the like, and to prevent a decrease in rigidity between a polyurethane foam and a spring member. Reinforcement base fabric for urethane foam molding, such as vehicle seats, which prevents generation of scratching noise caused by friction, is excellent in quietness, and is also excellent in reinforcement effect, its manufacturing method, and moldable polyurethane seat cushion material obtained by using the same It is about.

[0002]

2. Description of the Related Art As a cushioning material for a vehicle or the like, a soft polyurethane foam in-mold foam molding is mainly used.

In order for such a cushioning material to realize a good cushioning property, in the cushioning material structure shown in FIG. 3, which is generally used in many cases, the uppermost layer A in contact with the human body must be soft. The layer B to be present next should be a material having appropriate flexural rigidity or tension (high tensile elastic modulus), and the cushioning effect of the spring C layer which receives the impact force by receiving the B layer and produces a spring sensation. However, it is necessary to have a structure and action that can evenly disperse, keep the layer B flat, support it, and move up and down.

Also, from the viewpoint of ensuring the durability of such a foamed product in a flexible polyurethane foam mold, it is avoided that the polyurethane foam is rubbed by the contact of the spring (coil spring) and locally damaged. For,
Conventionally, a reinforcing base cloth has been put on the side of the spring material contacting surface of the following polyurethane foam to ensure good cushioning property and durability.

[0005] That is, to give a typical example thereof, slab urethane and frosted gauze are used as a reinforcing material, slab urethane is installed so as to be in contact with the surface of the foam molding die, and frosted gauze is installed inside it to inject the urethane liquid. The method of producing a soft polyurethane foam in-mold foam molded article in which a reinforcing layer is inserted by heating and pressurizing is often used and occupies the leading role.

The role of the slab urethane in this method is to impart rigidity to the resulting cushioning material and to prevent the foam die air vent hole from being blocked by the inflow of urethane, and the role of chills is to expand and expand the polyurethane. It is to allow the perilla to easily permeate and be embedded in and integrated with the polyurethane foam to improve the tensile elastic modulus and form an excellent reinforcing layer.

However, the slab urethane has an insufficient rigidity improving effect, and above all, the number of steps is large and the work is complicated, and it is difficult for the garment cloth, which is the reinforcing cloth, to conform to the cubic curved surface shape formed by the molded product. There were difficulties.

[0008] Next, the non-woven fabric (removable felt) has been developed and played a leading role for the purpose of solving the difficulty that it is difficult to conform to the shape of the above-mentioned ginseng and reducing the cost.

In order for this non-woven fabric to satisfy the required properties as a reinforcing fabric, it is necessary that it has an appropriate permeability for the urethane liquid that expands and expands. For this purpose, it has pores of an appropriate pore size. It is necessary to have porosity (apparent bulk density), and in order to provide sufficient reinforcing effect and rigidity, the non-woven fabric is embedded in the polyurethane that expands and expands, and the non-woven fabric intersection points are re-bonded with the polyurethane. In order to ensure conformability to the curved surface shape of the molded product, it is necessary to fill the nonwoven fabric with polyurethane foam and to have an appropriate rigidity and an appropriate apparent bulk density (porosity) that exhibits a high tensile elastic modulus. It was necessary to bond the intersections of the fibers constituting the non-woven fabric relatively gently so as to have a degree of freedom of tissue deformation.

From this point of view, non-woven fabrics having appropriate bulk density and porosity have been studied and developed by trial and error and used.

The criteria for setting the bulk density and porosity of these reinforcing non-woven fabrics are that the polyurethane that expands and expands permeates over the front face of the non-woven fabric, and that the non-woven fabric surface can be covered with a polyurethane film. It was selected in consideration of the fact that the permeability is too high and the polyurethane is suppressed to a level where it does not flow into the air vent hole of the molding die.

The above is the mainstream of the reinforcing fabric for in-mold expansion molding of flexible polyurethane foam.

However, under more gradual control, the necessary and sufficient permeability of polyurethane is stably secured, and the polyurethane is completely prevented from flowing into the air vent hole of the molding die, thereby producing with high yield and high productivity. In order to obtain a reinforcing cloth that is highly impregnated with urethane resin, has good permeability, contributes to increased rigidity and reinforcement, and has a high ability to integrate urethane foam and reinforcing cloth, a non-woven fabric layer for reinforcement with low bulk density and expansion A non-woven fabric for reinforcement, which is laminated and integrated, has been developed by providing a non-woven fabric layer having a relatively high bulk density, which is sufficient to block the inflow of incoming polyurethane into the mold air vent hole, as a barrier layer. 26,193).

Further, in order to reinforce the reinforcing effect and the effect of preventing the air vent holes from closing due to the inflow of polyurethane, a high basis weight non-woven fabric is used as a reinforcing base fabric to block the high reinforcing effect and the flow of polyurethane into the air vent holes due to the higher basis weight. In order to prevent this, one side of the high-density fabric is densified by embossing, etc.
The method disclosed in Japanese Patent Laid-Open No. 2-258332 is also invented and developed, in which the barrier layer is provided without being laminated and the polyurethane is more reliably prevented from flowing into the air vent hole. .

[0015]

With the recent trend toward high-end products, the functions required for a vehicle seat cushion material are not sufficient if only satisfying the excellent cushion function, which is achieved by the prior art. In addition to the functions, it is necessary to satisfy the requirements for satisfying environmental functions such as quietness, and the suppression of abnormal noise such as rubbing noise, bending and refraction noise due to friction between the soft polyurethane foam foam molded product and the spring material is strong. It came to be desired.

However, obtained by the prior art,
The flexible polyurethane foam in-mold foam moldings, which currently occupy the mainstream and are produced in large quantities by the method described in the above item, have a surface in contact with the spring material covered with a polyurethane film that penetrates a reinforcing cloth. Although the skin layer exerts a reinforcing effect in combination with the reinforcing cloth and satisfies the product function as it is, it is necessary to avoid generation of scratching noise due to friction between the polyurethane skin layer and the spring material. There is no.

Further, in the improved product obtained from Japanese Utility Model Publication No. 62-26193, the layer in contact with urethane foam is
Since it is coarse and bulky, it causes excessive urethane impregnation and filling, and as a result, there is a problem that it induces a decrease in rigidity due to a decrease in urethane density of the urethane foam molded article. In addition, JP-A-2-
Also according to Japanese Patent No. 258332, the layer of the base cloth which is in contact with the urethane foam has a high weight and bulky structure aiming at improvement of urethane impregnation, which causes excessive urethane impregnation filling, resulting in urethane density of the urethane foam molded article. There is a problem of inducing a decrease in rigidity due to the decrease. In addition, the high-density non-woven fabric layer that blocks the polyurethane that is about to flow out is in the outermost layer and is in contact with the spring material. Occurrence is unavoidable.

In order to solve the above-mentioned problems, the present invention prevents excessive deterioration of rigidity by preventing excessive urethane impregnation and filling during urethane foam molding, particularly molding of urethane foam molded articles. It also prevents the generation of abnormal noise,
Reinforcement base fabric for urethane foam molding, such as vehicle seats, which can provide the required urethane and base fabric integrity as a molded product by appropriate urethane impregnation and filling, and its manufacturing method, and high-performance moldable polyurethane seat using the same It is intended to provide a cushion material for use.

[0019]

[Means for Solving the Problems] In order to prevent a decrease in rigidity, suppress the generation of abnormal noise, and impart an excellent reinforcing effect and excellent processability, a polyurethane foam in-mold foamed article reinforcing base cloth (nonwoven fabric) ) Is required to be a laminated structure of nonwoven fabrics having different porosities shown in FIG.

In FIG. 1, 1 is a basis weight of 30 to 300.
A bulky non-woven fabric layer having g / m ² and a porosity of 90 to 94%, which contributes to the urethane barrier property. 2 is weight 20 to 10
It is a dense non-woven fabric layer with 0 g / m ² and a porosity of 87 to 91%. It has a suitable fluff on the contact surface with the urethane foam, and has a suitable void in the layer to obtain a suitable impregnation property and a blocking property. This contributes to both the impregnation function and the blocking function. These two layers are laminated and integrated to form the reinforcing base fabric for the foam-molded article of the present invention.

FIG. 2 shows a part of a cross section of a flexible polyurethane foam in-mold foam molded article manufactured by using this reinforcing base cloth.

In FIG. 1, 1 is a bulky non-woven fabric layer, 2 is a dense non-woven fabric layer containing polyurethane that has been foamed and penetrated in a foaming mold, and 3 is a polyurethane foam layer.

The functions required for the soft polyurethane foam in-mold foam molding reinforcing base cloth which prevents the deterioration of rigidity, suppresses the generation of abnormal noise, and has an excellent reinforcing effect and 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 the urethane foam and the reinforcing base cloth have a urethane resin permeability sufficient to firmly integrate them. It does not have excessive transparency.

Since the reinforcing base fabric follows the shape of the in-mold foam molded product and retains an excellent molding ability, the bonding between the inter-fiber intersections of the non-woven fabric is not strong, and the structure is flexible and the structure is flexible. Being a bonded structure

In order to exert a sufficient reinforcing effect, the bulk density of the non-woven fabric depends on the urethane resin impregnated during in-mold foam molding,
The highest possible filling level.

In order to prevent generation of scratching noise on the contact surface with the spring portion and generation of abnormal noise such as bending noise, the spring does not directly contact the urethane foam,
Reinforcement cloth is necessary because it needs to have a structure that can come into contact with a non-woven fabric having a relatively low bulk density (relatively high porosity), and it must also be a unitary structure with a reinforced urethane foam.
It is possible to form an integral structure by laminating a reinforcing non-woven fabric layer having a relatively low porosity (relatively high bulk density) having the functions of, and and a non-woven fabric having a relatively low bulk density (relatively high porosity). Required.

The permeability of the urethane resin at the time of in-mold foam molding specified in the item is a value determined by the pore size and the porosity (apparent bulk density) of the reinforcing nonwoven fabric, and the porosity is properly selected. By doing so, the polyurethane resin that expands and expands in the foam molding die is included and filled in the reinforcing base cloth, but it does not flow out to the outside (upper surface) of the reinforcing non-woven fabric in a large amount, and only a slight amount It turned out that it is possible to suppress and control.

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

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

Considering the case where the porosity is selected to be larger than 91%, in this case, the expanding polyurethane resin permeates the reinforcing non-woven fabric layer, overflows to the upper surface thereof, and flows into the air vent hole. Or, when the non-woven fabric layer is laminated on the reinforcing cloth, the non-woven fabric layer flows into the non-woven fabric layer, and the effect of preventing lowering of rigidity and noise is prevented.

On the contrary, when the porosity is selected to be less than 87%, it becomes difficult to impregnate the reinforcing non-woven fabric layer with the polyurethane resin, resulting in insufficient bonding between the reinforcing non-woven fabric layer and the polyurethane foam layer.

In order to secure the molding performance specified in the above item, it is necessary to gently bond the reinforcing non-woven fabric between the intersections.
Adhesion between the intersections of the constituent fibers of the reinforcing cloth without affecting the reinforcing effect is completed by the urethane resin that permeates and is impregnated during in-mold foam molding, and is completed. It is not necessary to carry out in advance.

On the other hand, in order to prevent the generation of abnormal noise, the spring may not come into direct contact with the urethane foam but may come into contact with a non-woven fabric having a relatively low bulk density (relatively high porosity), as defined in the section. If necessary, such a low-bulk-density nonwoven fabric is laminated and integrated with the reinforcing nonwoven fabric layer, and the reinforcing nonwoven fabric layer is directed toward the foamable urethane liquid side in the molding die during the production of the in-mold foam molded product. By installing the noise-preventing non-woven fabric layer toward the (upper surface) air vent hole side of the mold to manufacture a foamed product in the flexible polyurethane foam mold, the noise-prevention layer is prevented so that the spring and urethane foam do not come into direct contact. It is possible to manufacture a product in which the parts are integrated and the noise is prevented.

As a result of experiments, it is desirable that the non-woven fabric layer used for the abnormal noise prevention layer be bulky and have cushioning properties, and it is necessary that no abnormal noise is generated during bending. It has been clarified that a large and thick one having a large basis weight is required, and a material having a basis weight of 30 to 300 g / m ² and a porosity of 90 to 94% should be selected.

Thus, the basis weight 2 is used as the reinforcing non-woven fabric layer.
If a non-woven fabric with 0 to 100 g / m ² and a porosity of 87 to 91% is selected, the urethane resin permeates and fills the non-woven fabric layer during in-mold foam molding, and the urethane resin does not excessively flow out of the non-woven fabric surface and has a reinforcing effect. It is possible to select a reinforcing non-woven fabric layer for polyurethane foam in-mold foam molded articles, which is excellent in polyurethane foam and the non-woven fabric reinforcing layer is completely integrated.

The non-woven fabric of the present invention may be either spun-bonded non-woven fabric or short-fiber non-woven fabric as long as the above conditions are satisfied, and the constituent fiber material is not 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.

Predetermined porosity of these (apparent bulk density)
It is possible to manufacture a non-woven fabric laminate having the above-mentioned, and laminating and integrating non-woven fabrics having different apparent bulk densities (porosity) by appropriately selecting and combining the following methods.

The apparent bulk density (porosity) of the non-woven fabric depends on the denier of the non-woven fabric constituent fibers, the presence or absence of crimps, the shape of the crimps, the state of adhesion (conditions), the state of entanglement (conditions), press conditions such as calendering, etc. Since it is determined, a non-woven fabric having a predetermined apparent bulk density can be manufactured by selecting the conditions that match the purpose.

Generally, in order to obtain a non-woven fabric having a high apparent bulk density, use of low denier fiber, high needle density and deep needle depth during entanglement with a needle punch, temperature and pressure in calendering It is effective to give up.

To produce a laminated non-woven fabric having an integral structure, a. By stacking two types (different types) of webs and performing needle punching, it is possible to obtain webs that are laminated and integrated by mechanical entanglement.

This web is manufactured as it is or by impregnating it with an adhesive and drying it into a product, or if the web-constituting fiber is composed of a composite fiber or a heat-fusible fiber, it is heat-bonded into a product.

B. It can be manufactured by applying an adhesive to the joining surfaces of two kinds of non-woven webs, laminating and joining them.

At this time, the adhesive is applied to the coating of the adhesive solution (emulsion), the intercalation of the hot-melt adhesive sheet (nonwoven fabric sheet, film), etc., and each is dried or heat-treated for bonding.

When the non-woven fabric-constituting fibers themselves are composite fibers or include heat-fusible fibers, they can be joined and integrated by directly heat treating the laminate of both.

Next, in order to specifically show the embodiment of the present invention, it will be described in detail with reference to examples.

[0048]

EXAMPLE A nonwoven fabric 1 in which a web having a basis weight of 120 g / m ^{2 and having} a random loop structure made of polyethylene terephthalate fiber of 3 denier manufactured by the spunbond method was heat-pressed by calendering with a hot roll at 170 ° C. 1
And a web having a basis weight of 60 g / m ² of a random loop structure made of polyethylene terephthalate fiber of 1.5 denier produced by the spunbond method at 200 ° C.
Non-woven fabric 2 that is thermo-compression bonded by calendering with a hot roll
And were laminated, and needle punching was performed at a needle density of 40 / cm ² and a needle depth of 14 mm using an FPD1-40S needle manufactured by Organ Co., and entangled and integrated to obtain different porosities (different apparent bulks) of the constituent tissues shown in FIG. A laminated structure nonwoven fabric 3 having a density) was obtained.

In the nonwoven fabric 3 in FIG. 1, the measurement results showed that the nonwoven fabric layer made of the nonwoven fabric 1 had a porosity of 92%, and the reinforcing nonwoven fabric layer made of the nonwoven fabric 2 had a void ratio of 88%.

The obtained non-woven fabric 3 for reinforcing the foamed product inside the polyurethane foam is placed in the metal mold for foam molding.
The non-woven fabric 2 toward the upper surface of the mold, that is, toward the air vent hole, and the non-woven fabric 2 toward the side where the foaming urethane resin is added. Add the foaming urethane resin in the usual manner, and foam and mold polyurethane under heat and pressure. Then, a foamed molded product in a flexible polyurethane foam mold was prepared.

In order to confirm the state of penetration and permeation of the polyurethane resin into the laminated structure nonwoven fabric 3 in the obtained molded product and the bonding state between the polyurethane foam layer 4 and the laminated structure nonwoven fabric 3 in FIG. The product was cut and the state of the cross section was observed and the bonding strength between the polyurethane foam layer 4 and the laminated structure nonwoven fabric 3 was examined.

As a result of the observation, the polyurethane resin expanded and expanded evenly penetrates and fills the two layers of the non-woven fabric, and slightly bleeds to the boundary layer with the one layer of the non-woven fabric. It has been realized.

Further, regarding the bonding strength between the polyurethane foam layer 4 and the non-woven fabric 3 having a laminated structure, it was shown that the polyurethane foam layer was broken before the interface was peeled off, and sufficient bonding was performed.

Further, in the abnormal noise generation model test in which one surface of the nonwoven fabric which is the abnormal noise generation preventing layer is brought into contact with the coiled spring and pressure and depressurization are repeated, generation of abnormal noise was not detected at all. Comparative Example Only the porosity of the two layers of the nonwoven fabric for reinforcing layer in the example is 83
% And a non-woven fabric layer having a porosity of 95% as a whole to form a flexible polyurethane foam in-mold foam molded product in the same manner as in the example, and permeation of the polyurethane resin into the laminated structure non-woven fabric 3 in the molded product. The transparent state and the bonded state between the polyurethane foam layer and the laminated structure nonwoven fabric 3 were observed.

The observation result shows that in the sample having a porosity of 95% as a whole, the expanded and expanded polyurethane resin may partially permeate the non-woven fabric layer and overflow to the outside to block the air vent hole of the molding die. Shows that the polyurethane resin reaches the surface layer of the non-woven fabric and has no noise suppressing effect. In the sample in which the void ratio of the two layers of the non-woven fabric for the reinforcing layer is changed to 83%, the polyurethane resin for the two non-woven fabrics of the reinforcing layer is shown. There was a part where the permeation and impregnation were insufficient, and there was a part where the bonding between the polyurethane foam layer 4 and the laminated structure nonwoven fabric 3 was partially insufficient.

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

[0057]

EFFECT OF THE INVENTION A bulky nonwoven fabric layer having a basis weight of 30 to 300 g / m ² and a porosity of 90 to 94% and a basis weight of 20 to 1
Rigidity of urethane foam molded products by using a non-woven fabric obtained by laminating and integrating a dense non-woven fabric layer with a porosity of 87 to 91% at 00 g / m ² as a reinforcing base fabric for soft polyurethane foam in-mold foam molded products. It has the ability to prevent deterioration and the generation of abnormal noise.

In the manufacturing method, since the urethane foam impregnation begins with a layer having a proper urethane impregnation function and a urethane blocking function, excessive impregnation and filling of the urethane foam can be prevented to obtain a urethane foam molded article. This prevents the density and rigidity from decreasing, and provides the necessary integration of the base cloth and urethane as a molded product. Furthermore, by appropriately blocking urethane in the layer in contact with the foamed urethane, the amount of urethane passing through the layer in contact with the coil spring etc. is reduced, and the urethane barrier property required in that layer is reduced, that is, Low basis weight, and as a result, lower basis weight of base fabric,
It becomes possible to perform urethane foam molding for vehicle seats and the like, which can reduce the weight of the molded product. Then, as the product, it is possible to obtain a cushioning material having excellent cushioning performance based on imparting excellent tensile elastic modulus and good sitting comfort and excellent durability due to an excellent reinforcing effect.

[Brief description of drawings]

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

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

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

[Explanation of symbols]

 1 Bulky Nonwoven Layer 2 Dense Nonwoven Layer 3 Reinforcement Base Fabric for Foam Molded Product 4 Polyurethane Foam Layer A Polyurethane Foam Layer B Reinforcement Layer C Spring

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location B29L 31:54 4F (72) Inventor Masanobu Yamada 2-8 Dojimahama, Kita-ku, Osaka Toyobo Co., Ltd. (72) Inventor Sadakuni Shiotani 982 Kaneda, Atsugi-shi, Kanagawa Toyoso Franc Co., Ltd.In-house (72) Inventor Shigeru Inage 982 Kaneda, Atsugi-shi, Kanagawa Toyoso Franc Co., Ltd.

Claims (3)

[Claims] 1. A dense nonwoven fabric having a basis weight of 20 to 100 g / m ² and a porosity of 87 to 91%, and a layer contacting a coil spring having a basis weight of 30 to 300 g / m ² and a porosity of 90. Reinforcement base fabric for urethane foam molding, which is made of a bulky non-woven fabric of 94% to 94%, and these are laminated and integrated. 2. When producing an in-mold foamed article, a dense non-woven fabric having a basis weight of 20 to 100 g / m ² and a porosity of 87 to 91%, and a porosity of 90 to 94% at a basis weight of 30 to 300 g / m ² . A bulky non-woven fabric is laminated and integrated, and foamable urethane liquid is supplied to the dense non-woven fabric side,
A method for producing a reinforcing base fabric for urethane foam molding, which comprises infiltrating urethane into the dense non-woven fabric layer for foaming and reinforcing the same, and at the same time, integrating with the polyurethane foam to be formed. 3. A dense non-woven fabric having a basis weight of 20 to 100 g / m ² and a porosity of 87 to 91%, and a layer in contact with a coil spring having a basis weight of 30 to 300 g / m ² and a porosity of 90. To 94% bulky non-woven fabric, and a formable polyurethane seat cushion material made of a urethane foam molding reinforcing base fabric that is made by laminating and integrating these.