JP5605148B2 - Non-woven fabric for foam molded article reinforcement and method for producing the same - Google Patents

Description

  The present invention relates to a nonwoven fabric for reinforcing a foam molded article having a complicated shape used for furniture or a vehicle seat. More specifically, the present invention relates to a non-woven fabric for reinforcing a foamed molded article that has few problems of bleeding and wrinkles even when lightweight, and has excellent processability and handleability, and a method for producing the same.

  In recent years, soft foamed urethane moldings have been widely used as cushioning materials such as beds and seats, armrests, cushioning materials, and shock-absorbing materials. Is also used. Such a reinforcing material is located between the urethane foam molded body and a support such as a metal spring, and distributes the cushioning action of the support evenly and protects the urethane foam molded body from the friction received from the support. Is responsible for. As the quality demanded by consumers becomes higher, there is a growing demand for eliminating scratching noise caused by friction between urethane and metal springs that ooze into the reinforcing material when seats are used. A reinforcing material made of a non-woven fabric that has a bulky layer and a dense layer and prevents the seepage of urethane in the dense layer has been proposed (see, for example, Patent Documents 1 to 5).

  However, since such a reinforcing material has poor moldability at the time of urethane foam molding, the design property that has been strongly demanded in recent years is high. There was a problem that a defect was generated, and the exudation of urethane from this caused an increase in scratching sound or breakage due to friction with the metal spring.

  Recently, weight reduction has been promoted by increasing the expansion ratio of urethane foam (reducing the density of urethane foam). Especially in automobile applications, the expansion ratio of urethane has been increasing for the purpose of improving fuel economy through weight reduction. . When the expansion ratio becomes high, when it is used as a cushioning material or the like, it becomes easy to cause settling due to repeated loads, and the role played by the reinforcing material is becoming more important for the prevention.

  Therefore, Patent Document 6 has been proposed as a reinforcing material that can be used for urethane foam molding with large irregularities by suppressing the 5% elongation stress at 65 ° C. and 100 ° C. of the dense layer that prevents the urethane from seeping out. However, such a reinforcing material can prevent exudation of the foaming agent by the method of laminating and entangling the low-weight dense layer and the base material layer, but the elongation is low and it is difficult to cope with large elongation. There was a problem that the adhesiveness deteriorated. Furthermore, since each layer is formed and subjected to the laminating process, there is a problem that the process becomes complicated and the cost is increased. Moreover, although the method of carrying out the needle punching after the calendar process of the single layer PBT spunbond nonwoven fabric is also proposed in the Example of patent document 6, the rigidity provided by the calendar process (by the heat history received by the calendar process). This is considered to be because the crystallization is promoted), but it is difficult to be softened by the needle punching process, and there is a problem that the moldability in the deep drawing shape is inferior.

  Further, as a method for improving punchability, Patent Document 7 proposes a method in which a nonwoven fabric made of carbon black-containing fibers and a non-containing nonwoven fabric are laminated and entangled. However, this method has greatly improved punchability and handling properties, but in the deep-drawn foamed urethane molding with complicated and large irregularities, the followability to the mold becomes insufficient, resulting in the occurrence of missing and wrinkles. There remains a problem that cannot be sufficiently prevented. In addition, since the layer entanglement process is performed after forming each of the two layers, there is a problem that the process becomes complicated and the cost increases.

  Patent Document 8 proposes a method of thermocompression bonding one side of a high-weight single-layer nonwoven fabric. In this method, although the complexity of the processing process is improved, since one side is thermocompression bonded and rigidized, in the deep-drawn urethane foam molding with complicated and large irregularities, the followability to the mold is insufficient. As a result, there remains a problem that the occurrence of lack of meat and wrinkles cannot be sufficiently prevented.

Patent Document 9 proposes a method of obtaining a nonwoven fabric for molding with low air permeability by a method in which a single-layer spunbonded nonwoven fabric composed of fibers having medium orientation is temporarily embossed and then needle punched and densified by shrinkage treatment. . In such a method, only a low air permeability of 0 to 35 cc / cm ³ / sec can be obtained by being densified by shrink heat treatment. Therefore, in a complicated deep drawing shape, the moldability is inferior and the finished shape is inferior. There is a problem that gets worse. Further, the process is complicated and not preferable in terms of cost.

  Single-layer spunbonded nonwoven fabric consisting of fibers with medium orientation is temporarily embossed and then needle punched, then further single-sided heat embossed, then densified by shrinkage treatment, and the loop formed by shrinkage is raised by buffing Patent Document 10 proposes a method for obtaining a nonwoven fabric for thermoforming by a method. This method is suitable for foam molding because the pressure-bonding part extends over the entire thickness direction of the nonwoven fabric and is not made into a two-layer structure in the thickness cross-sectional direction, and urethane oozes easily from the raised loop part. There is no problem.

  As a surface fastener female material, a method of forming a loop on one side, thermocompression bonding, and fixing the loop with an adhesive is proposed in Patent Document 11, but it is useful as a fastener material. In some cases, the moldability is inferior and the finished shape is poor, which is not suitable for foam molding.

  As a low modulus material, Patent Document 12 proposes a reinforcing material for foam molding obtained by applying only embossing to a crimped polypropylene fiber nonwoven fabric. This method is a method in which a crimped part is partially formed by embossing on a bulky bulky layer that is crimped. This method has two layers in the thickness cross-sectional direction of the nonwoven fabric. Although it is not structured, exudation from the non-embossed portion is improved as compared with Patent Document 10, but exudation of urethane tends to occur at a low basis weight, which is problematic for foam molding.

Japanese Utility Model Publication No. 62-26193 JP-A-2-258332 Japanese Patent No. 2990207 Japanese Patent No. 2990208 Japanese Patent No. 3048435 Japanese Patent No. 3883008 JP 2007-33159 A Japanese Patent No. 2611422 Japanese Patent No. 2514193 Japanese Patent Publication No. 07-30501 JP 2000-265354 A JP 2009-167570 A

  The present invention is based on the background of the prior art, and relates to a lightweight non-woven fabric for foam molded article reinforcement used for furniture or vehicle seats. It is an object of the present invention to provide a non-woven fabric for a foam molded article reinforcing material that has few problems of wrinkling of a reinforcing material due to good shape followability to a mold and is excellent in processing and handling and a method for producing the same.

As a result of intensive studies to solve the above problems, the present inventors have found that even when a short fiber nonwoven fabric with a low basis weight is used, the thickness at a load of 7 g / cm ² is 0.4 to 2.0 mm. By using a material with an appropriate heat-bonded area, it is possible to produce a foamed molded article with excellent followability even in deep drawing shapes with large irregularities during cold foaming, excellent extruding of foaming agent, and good finished shape. The obtained foamed molded article having a good finished shape forms a reinforcing layer firmly bonded to the foamed layer, and it is found that a foamed molded article having excellent durability can be obtained. Reached completion.

That is, the present invention is as follows.
1. A non-woven fabric used as a reinforcing material for urethane foam moldings, thickness at 7 g / cm ² load is 0.4 to 2.0 mm, tensile strength is 50 N / 5 cm or more, elongation is 100% or less, A non-woven fabric for reinforcing foamed articles comprising a short-fiber non-woven fabric having a tear strength of 20 N or more and having at least a part thermally bonded.
2. ^{2. The} nonwoven fabric for foam molded article reinforcing material according to 1 above, having a basis weight of 60 to 140 g / m ² , a fragile air permeability of 50 to 350 cc / cm ² / sec, and a tear strength after urethane impregnation of 18 N or more.
3. The main constituent fiber is a non-woven fabric made of polyester fiber having a fineness of 1.0 to 6.7 dtex, containing 5 to 50% of a composite fiber containing a low melting point component, and at least partially compressed and densified. The nonwoven fabric for foam molded article reinforcing material according to 1 or 2 above, wherein
4). Production of a nonwoven fabric for reinforcing foam-molded article according to any one of 1 to 3 above, wherein after forming a fiber entanglement with a web composed of short fibers, partial adhesion is imparted by an air-through method and further brought into contact with a heating roll. Method.

  The nonwoven fabric for foam-molded article reinforcing material of the present invention is excellent in anti-bleeding property, installation handling property, processability, and molded product quality even at a low basis weight. In other words, the non-woven fabric for reinforcing material is not too hard and not too soft, and it can be attached to the molding frame well, and has good followability and good air permeability even in deep drawing molding at low temperature foaming typified by cold foaming. Occasionally wrinkles, thinning and resin loss can be prevented, and the non-woven fabric for reinforcing material becomes a molded product that is firmly bonded to the foam, suppressing abrasion, bending and refraction noise, and shape retention durability and wear resistance In addition, it is possible to provide a non-woven fabric for reinforcing foam-molded products suitable for low-temperature cold foaming, which can produce a light-weight cold-foamed molded article. Moreover, it becomes possible to provide a lightweight nonwoven fabric for foam molded article reinforcing material having an appropriate tear strength and flame retardancy after being combined with urethane, and a method for producing the same.

The material used in the nonwoven fabric for foam molded article reinforcing material of the present invention is not particularly limited, but it is recommended to use a general-purpose thermoplastic resin with a low price such as polyester or polyolefin, and the nonwoven fabric is particularly configured. It is preferable that the main fiber to perform is a polyester fiber. By using polyester fiber, it becomes easy to obtain excellent mechanical properties (tensile strength and tear strength), dimensional stability in the urethane foaming temperature range (about 65 to 100 ° C.), and creep resistance properties. Polyesters include homopolyesters such as polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polycyclohexanedimethyl terephthalate (PCHT), polytrimethylene terephthalate (PTT), polylactic acid (PLA), and copolyesters thereof. Can be illustrated. There is no problem in terms of physical properties even if PET is used whose raw material is bio-derived ethylene glycol as a component.
Polyolefin-based materials such as polypropylene and polyethylene can also be used, but can be used by mixing with polyester-based fibers, which are the main constituent fibers of nonwoven fabrics excellent in mechanical properties and creep resistance properties required in the present invention. preferable.
Moreover, in this invention, modifiers, such as an antioxidant, a light-resistant agent, a coloring agent, an antibacterial agent, a flame retardant, a hydrophilizing agent, can be added as needed within the range which does not reduce a characteristic.

The nonwoven fabric for foam molded article reinforcing material of the present invention needs to have a thickness of 7 g / cm ² load of 0.4 to 2.0 mm. More preferably, it is 0.8-1.4 mm.
At the time of urethane foaming, the nonwoven fabric for reinforcing material is set in advance inside the mold using pins, magnets, double-sided tape, etc. Supplied. At this time, the gas generated by urethane foam passes through the reinforcing nonwoven fabric layer, and then the urethane foam is impregnated into the reinforcing nonwoven fabric layer. When the thickness of the reinforcing material nonwoven fabric is less than 0.4 mm, urethane passes through the layer regardless of the air permeability, and the urethane leaks out to the mold surface, and the cushion surface after molding It is considered that a urethane leak layer is formed on the surface, and abnormal noise is generated by friction with the S spring that supports the urethane molded body in actual use.
On the other hand, if the thickness exceeds 2.0 mm, the tensile strength of the sheet becomes too low or the elongation rate is too high, which tends to cause problems in practical characteristics and handling properties. In addition, if the thickness of the reinforcing material exceeds 2.0 mm, the fiber gap distance becomes too large, which makes it easier for urethane to permeate through the layer or to reduce the dimensional accuracy when sewing and using. It is easy to produce. Furthermore, as a result of studies by the present inventor, local distribution spots are likely to be large on the two-dimensional surface or three-dimensional surface of the sheet. It tends to cause problems such as an increase. Further, since the restraint points due to the adhesion or entanglement of the fibers are reduced, it becomes easy to drop the fibers at the time of punching and to reduce the handling property due to fluffing.

Although the method for controlling the thickness at a load of 7 g / cm ² is not particularly specified, in order to reduce the thickness, when the needle punch method is used, the piercing density is increased or the piercing depth is increased. It ’s fine. When using the air-through method, it is possible to increase the processing temperature, increase the circulating air speed, or perform heat treatment while sandwiched between nets.

  As a method for controlling the thickness, contacting with a heating roll is also an effective method. An appropriate thickness can be achieved by providing a clearance between the opposed heating rolls. Alternatively, by using a roll on one side made of resin or rubber, it is possible to prevent the thickness from becoming too small due to being crushed without setting a clearance. Moreover, it becomes easy to control the thickness by appropriately setting the hardness of a resin roll or a rubber roll. Although the thickness controllability is inferior, it is also possible to take a method such as indirect heating with a far-infrared heater or the like or contact with a heated bar or plate.

  For example, in needle punching, it is generally possible to set mechanical properties such as tensile strength and tear strength to desired values by increasing the piercing density to some extent or by increasing the piercing depth. However, it should be noted that if it exceeds an appropriate condition, other problems such as generation of dust and a decrease in strength due to fiber cutting often occur.

  Further, when a calendar roll is used to perform the thermal bonding process, the thickness can often be increased by setting the processing temperature low, increasing the processing speed, or providing a clearance. Also, when using a hot embossing roll to prevent thickness reduction due to contact with a high-temperature metal body, the holding area (engraving convex area) can be reduced, the embossing convex depth can be increased, the processing pressure It is also preferable to lower the value. Since these condition settings are governed by complex factors of related parameters, it is necessary to determine appropriate conditions based on the experience of the person concerned.

  The tensile strength is 50 N / 5 cm or more and the elongation is 50 to 100% of the non-woven fabric for a foam molded article reinforcing material of the present invention. If the tensile strength is less than 50 N / 5 cm, good handleability cannot be maintained, and workability in the production process deteriorates. If the elongation is less than 50%, the deformation followability in mold molding that requires partial bending and extension, such as deep drawing molds, will be insufficient, resulting in a poor finished shape or tearing Is not preferable. When the elongation rate exceeds 100%, when the reinforcing material is punched or sewn, it will be deformed to cause a deviation from the desired shape, or when the sewn product is set in the mold, it will be caught on the set pin In some cases, the sheet is stretched too much and the setability becomes worse.

  The tear strength (single tongue method) of the nonwoven fabric for foam molded article reinforcement of the present invention is 20 N or more. More preferably, it is 30 N or more. The tear strength is related to the durability of the reinforcing material, and is considered to be related to the limit at which the reinforcing material layer is broken when a high load is applied.

  The tear strength (single tongue method) after urethane impregnation of the nonwoven fabric for foam molded article reinforcing material of the present invention is preferably 18 N or more, particularly preferably 20 N or more. Since the tear strength after impregnation with urethane is related to the hardness of the urethane itself and the adhesive strength to the fibers, it is necessary to determine the urethane composition with attention.

The nonwoven fabric for foam-molded article reinforcing material of the present invention comprises only short fiber nonwoven fabrics in order to maintain excellent moldability. The short fiber non-woven fabric can be uniformly deformed by the mold following deformation at the time of molding, so that it does not break, and a beautiful finished molded product can be obtained. A general short fiber nonwoven fabric is excellent in bulkiness, but has many cut ends of fibers, and therefore, is often inferior in mechanical properties as compared to a long fiber nonwoven fabric or a long fiber nonwoven fabric / short fiber nonwoven fabric composite. In particular, low-weight short-fiber non-woven fabrics are preferred because they have poor mechanical properties due to fewer fiber bonding or entanglement points, and are easy to break during mold setting, or are easily deformed due to follow-up spots due to mold deformation during molding. It has been said that there is no. As a result of the study by the present inventors, it has been found that these problems can be avoided by selecting appropriate raw materials and processing methods.
The mechanical properties after foaming tend to decrease the tear properties due to the limited freedom of fiber movement due to the presence of urethane, but can be adapted by selecting an appropriate fineness and basis weight.

Conventional nonwoven fabrics for foam-molded article reinforcing materials often use long fiber nonwoven fabrics or composites of long fiber nonwoven fabrics and short fiber nonwoven fabrics. This is not only because the long-fiber nonwoven fabric has excellent strength characteristics, but with the same basis weight, the sheet has high homogeneity within the two-dimensional surface or three-dimensional structure of the nonwoven fabric, and the sparse structure tends to cause exudation of urethane or the like. The reason is that the probability of forming a part is very low. However, when the mold shape having a complicated shape is becoming common, there is a case where wrinkles are generated at the time of foaming because the sheet is too stiff.
The short fiber nonwoven fabric constituting the present invention may be a single layer or a structure in which two or more layers are laminated. It is also one of the preferable forms to laminate short fiber layers having different fiber diameters as required.
From the viewpoint of productivity and cost, it is considered preferable to satisfy the required characteristics even if a single layer is used. As a result of intensive studies, the present inventors have made a proper amount of thermal bonding by using an air-through method or a heating roll after forming an appropriate fiber entanglement point in advance by a needle punch or spunlace method even in a single layer. By increasing the number of points, the present inventors have found that even a bulky and low-weight short-fiber nonwoven fabric as a whole contributes to maintaining the mechanical properties by the fiber entanglement points and the fiber mutual adhesion points, and can express the necessary mechanical performance.
In addition, it is also one of preferable modes that the nonwoven fabric of the present invention is previously placed in a desired mold and molded and then set in a foaming mold.

In order to reduce the weight of the nonwoven fabric for foam-molded article reinforcing material of the present invention, it is one of the preferred forms to reduce the weight by using a nonwoven fabric composed of one layer. However, if one layer is used, problems such as mechanical properties required as a reinforcing material and handleability during processing are likely to occur. Therefore, the following structure is preferably formed.
It is preferable that the nonwoven fabric of the present invention is entangled three-dimensionally by a needle punch method, and at least a part thermally bonded is formed. The apparent density is preferably a non-woven fabric of 0.05 to 0.15 g / cm ³ .
The nonwoven fabric for foam molded article reinforcing material of the present invention is installed on a surface (spring receiving surface) that comes into contact with a metal spring material and the like, and as a cushion layer, it has a sound damping function such as rubbing with the spring material, bending, refraction sound, and molding. In order to achieve the wear resistance of the product, it is necessary to have appropriate mechanical properties. For this purpose, it is necessary that there are appropriate amounts of entanglement points and partial adhesion points of desired fibers. If the fiber entanglement points and adhesion points are not formed in an appropriate amount, the sound damping function such as abrasion, bending, and refraction sound with the spring material will be reduced. If it becomes too high, mold followability is hindered, resulting in poor molding finish. Moreover, when a nonwoven fabric consists of two or more layers, it is preferable to laminate | stack the nonwoven fabric layer of a fine fineness, and the nonwoven fabric layer of a thick fiber.

In the case of using a single layer nonwoven fabric mainly composed of short fibers made of polyester as the nonwoven fabric for foam molded article reinforcing material of the present invention, a pressure-bonded and densified portion is formed on at least one side, and the pressure bonding A nonwoven fabric structure in which a protruding fiber structure is formed in the dense surface layer is preferable. In addition, the protruding fiber structure in the present invention is collectively referred to as a protruding fiber structure in which a plurality of fibers are protruded from a nonwoven fabric surface as a loop or a cut fiber.
In the present invention, molding is performed using the pressure-bonding dense surface layer side on the boundary surface side with the foaming agent, the protruding fiber structure is embedded and solidified in the foamed urethane layer, exhibits an anchor effect, and the nonwoven fabric and foamed urethane that are reinforcing materials It enables strong bonding between layers.
If a protruding fiber structure is formed on the pressure-bonding dense surface layer side, it is easy to obtain an anchor effect to the urethane foam layer, and it becomes difficult to cause peeling between the reinforcing material layer and the foam layer due to a decrease in the bonding strength against wear and deformation. As a result, it is easy to prevent a decrease in durability due to a decrease in the sound damping function such as scratching, bending, and refraction, and a reinforcing effect.

By adjusting the air permeability by controlling the apparent density and thickness, the amount of outgassing at the time of foaming is controlled to improve the filling property of the foaming agent, and the bulky layer side is made flexible so that the mold at the time of molding processing Since followability can also be improved, it is a more preferable embodiment. As the entanglement method for forming the protruding fiber structure, a known spunlace method, needle punch method or the like can be applied. As a more preferable entangled porous softening and protruding fiber structure forming method in the present invention, entanglement softening and protruding fiber structure formation by the needle punch method are recommended.
The protruding number density of the preferable protruding fiber structure in the present invention is 20 to 100 / cm ² . If it is less than 20 pieces / cm ² , the softening effect due to the entanglement treatment effect and the anchor effect may be insufficient. If it exceeds 100 pieces / cm ² , the dense surface layer becomes soft and the foaming agent shielding layer effect is obtained. May decrease. In addition, the number of protrusions of the protruding fiber structure in the present invention is counted as one form in which a plurality of fibers protrude from one hole generated by one entanglement process.
The protrusion density of the more preferable protruding fiber structure of the present invention is 30 to 160 pieces / cm ² , more preferably 45 to 110 pieces / cm ² .

  The preferable loop height formed by the protruding fiber structure in the present invention is 1 to 4 mm. If the loop height is less than 1 mm, the anchor effect may be insufficient. If the loop height exceeds 4 mm, there may be a problem in workability when set on the mold by catching. The more preferable loop height of the present invention is 1.5 to 4 mm, and the more preferable loop height is 2 to 3 mm.

  The protruding fiber structure forming effect by the needle punch method depends on the needle depth, and it is preferable to make it as shallow as possible under the condition that a necessary protruding fiber length can be formed. If the needle depth is deep, the opening diameter becomes large and the foaming agent may ooze out. For example, in order to set the protruding fiber loop length to 3 to 10 mm, the needle depth is preferably set to 9 to 12 mm.

  It is preferable that the non-woven fabric for reinforcing material processed by the needle punch method subsequently forms a partial thermal bonding portion by the air-through method. The process of the air-through method is particularly suitable as the method for producing the nonwoven fabric for reinforcing material of the present invention because the partial adhesion point can be increased without reducing the thickness. In the case of a polyester fiber, the processing temperature is preferably about 90 to 150 ° C., and a suitable adhesion state can be obtained by performing heat treatment for 30 to 40 seconds. The setting of the processing temperature can be controlled by the melting point and the mixing ratio of the low melting point component.

A preferable basis weight of the nonwoven fabric for foam molded article reinforcing material in the present invention is 60 to 140 g / m ² . A more preferable basis weight is 80 to 120 g / m ² , and more preferably 90 to 110 g / m ² . When the basis weight is less than 60 g / m ² , the bulky layer is thinned, and the function of preventing exudation of the foaming agent at the time of foam molding and the abrasion, bending, and refraction sound when formed into a molded product are suppressed and maintained. It may be difficult to simultaneously satisfy the functions of imparting shape durability and wear resistance. If the basis weight exceeds 140 g / m ² , weight reduction is hindered.

The air permeability of the nonwoven fabric for foam molded article reinforcing material in the present invention is preferably 50 to 350 cc / cm ² / sec. When the air permeability is less than 50 cc / cm ² / sec, the expansion air escape during foam molding becomes non-uniform, which may result in the occurrence of thinning and resin loss. When the air permeability exceeds 350 cc / cm ² / sec, the foaming agent Bleeding due to leakage may occur.
The more preferable air permeability in the present invention is 100 to 280 cc / cm ² / second, and more preferably 150 to 260 cc / cm ² / second.

  The fineness of the fibers mainly constituting the nonwoven fabric for foam molded article reinforcing material in the present invention is preferably 1.0 to 6.7 dtex, more preferably 1.5 to 4.4 dtex. If the fineness is less than 1.0 dtex, the wear resistance is inferior, the durability is insufficient, and it is difficult to increase the thickness ratio when the load is changed. On the other hand, if it exceeds 6.7 dtex, the number of fiber components decreases, the density of the nonwoven fabric structure decreases, the air permeability becomes too high, and there may be a problem in moldability, and the cushion layer function of the spring material may be increased. It may be insufficient.

In the nonwoven fabric for foam molded article reinforcing material in the present invention, it is preferable to contain a composite fiber of two or more components including a main component and a low melting point component whose melting point is 20 ° C. or more lower than the main component.
In the case where the main component fiber is a polyethylene terephthalate (pet) fiber, it is one of preferred embodiments that the composite fiber includes two components of a low melting point pet and pet. The form of the composite fiber may be a core-sheath structure or a side-by-side structure. In the case where it is desired to increase the thickness of the nonwoven fabric, it is also one of preferable modes to use a hollow core sheath or a hollow side-by-side fiber.
Further, a core-sheath type composite fiber of polyethylene and pet can also be used by mixing with pet fiber.
For the purpose of setting the adhesive strength and bulkiness to desired values, the fineness of the composite fiber is preferably 2.2 to 8.9 dtex, and more preferably 4.4 to 6.7 dtex.

The reason why the composite fiber is used in the nonwoven fabric for reinforcing foamed product according to the present invention is as follows. Ordinary short fiber nonwoven fabrics are inferior in strength to long fiber nonwoven fabrics, and the tendency is particularly pronounced in nonwoven fabrics having a basis weight of 140 g / m ² or less that are suitably used in the present invention. It was difficult to use as a non-woven fabric. As a result of intensive studies to solve the problem, it was found that the tensile strength and elongation of the nonwoven fabric can be controlled to desired values by using an appropriate amount of the composite fiber. Further, the nonwoven fabric for reinforcing material is often used after being punched, but by providing an adhesive portion with a composite fiber, it is possible to reduce the dropping of the fiber. As a result, it is possible to prevent an increase in the pressure loss of the recovery filter for dust (fiber waste etc.) installed for the purpose of preventing environmental pollution due to dust in the exhaust gas containing urethane foam gas installed in the process. . In addition, it is possible to prevent the problem that the sheet is entangled with the hands or gloves of the operator who sets the reinforcing material in the mold.

  In the nonwoven fabric for foam molded article reinforcing material in the present invention, the mixing ratio of the composite fibers is preferably 5 to 50%, more preferably 10 to 40%. If the mixing ratio of the composite fiber is lower than 5%, not only the mechanical strength characteristics are inferior, but also when set on a pin of a mold, if it slips, the elongation becomes too large and installation becomes difficult, or sagging occurs. It is easy to become a factor inducing the occurrence of wrinkles. In addition, there are many problems such as fiber dropping and fluffing after punching and cutting, and workability in setting to a mold is lowered. On the other hand, when the mixing ratio is higher than 50%, the sheet is too stiff and the setability is deteriorated, and the problem is that wrinkles are easily generated during foam molding. In addition, when used in automobiles or the like, the flame retardancy is deteriorated due to an increase in low melting point components, and it becomes difficult to conform to the fmvss302 standard even after urethane foam composite.

  The flexibility of the nonwoven fabric for foam molded article reinforcing material of the present invention is preferably 30 mm to 150 mm as the bending resistance measured by a 45 ° cantilever method. If it is less than 30 mm, if it is too soft, it may cause a problem in handling properties, and if it exceeds 150 mm, it may be too hard and cause problems in setting properties to the mold. More preferably, the bending resistance is 40 to 100 mm, and more preferably 50 to 80 mm. In the present invention, it is desirable that both the vertical and horizontal directions are satisfied. However, if one direction is deviated, it may be considered an allowable range if the average value in the vertical and horizontal directions is satisfied.

  Using the nonwoven fabric for foam molded article reinforcing material of the present invention, it was cut into a predetermined shape, set in a cushion mold, injected with foaming agent, and molded into a vehicle cushion. The molded cushion is finished in a good shape, does not exude foaming agent, suppresses abrasion, bending and refraction sound with the spring backing material, and is a foam molded product with excellent shape retention and wear resistance. It was.

  Hereinafter, the present invention will be described more specifically with reference to examples, conventional examples, and comparative examples, but the present invention is not limited to these examples. In addition, the evaluation method used by the Example and comparative example of this invention was performed with the following method.

(1) Fineness [dtex]
Five arbitrary points of the sample were selected, and the single fiber diameter was measured at n = 20 using an optical microscope, and the total average value (D) was obtained. Five fibers at the same place were taken out, and the specific gravity of the fiber was measured at n = 5 using a density gradient tube to obtain the total average value (ρ). Subsequently, the fineness is expressed by dtex by converting the average single fiber cross-sectional area and the average specific gravity into a weight of 10,000 m.

(2) Weight per unit [g / m ² ]
Measured according to JIS L 1906 (2000) “Mass per unit area”.

(3) Thickness [mm]
Conforms to the JIS L 1906 (2000) "thickness", was measured at a load of 7gf / cm ² and the load 20gf / cm ^2.

(4) Apparent density [g / cm ³ ]
It calculated using the following formula from the fabric weight and thickness (load 20gf / cm < ² >) measured by said (2) and (3).
Apparent density = basis weight ÷ thickness ÷ 1000

(5) Strong elongation property and tear strength of nonwoven fabric Tensile strength and elongation were measured according to JIS L 1906 (2000) “Tensile strength and elongation”. The tear strength was measured according to JIS L 1906 (2000) “Tear Strength Single Tang Method”.
Further, the tear strength of the nonwoven fabric after the urethane impregnation composite is measured after peeling the reinforcing material from the foamed urethane layer. It is preferable to measure by reducing the adhesion amount of urethane as much as possible. However, if the adhesion amount is about 5 to 30 g / m ^{2, the} tear strength is hardly affected.

(6) Air permeability (cc / cm ² / sec)
It was carried out with a fragile air permeability measuring machine according to JIS L 1906 (2000) “Breathable Frazier Form Method”.

(7) Flexibility (flexibility)
It shows by the average value of the value measured based on JISL1906 (2000) "bending softness 45 degree cantilever method".

(8) Foaming evaluation Cut the cushion pad mold into a predetermined shape, and set the non-woven fabric for reinforcing foam material with a 30mm hole at the center and 3 points spaced at 10cm intervals so that it conforms to the shape. Then, sensory evaluation was performed with the set state as set property, and then cold foaming at 65 ° C. was performed with an MDI (diphenylmethane diisocyanate) two-component urethane resin to evaluate a molded product having a urethane density of about 46 kg / m ^3. The visual judgment was performed.
(8-1) Setability Familiar and easy to set in mold: ○, Familiar but difficult to set: Δ, Familiar and difficult to set: × Sensory evaluation.
(8-2) Exudation No urethane exudation on the reinforcing material surface of the molded product: ○, exudation fine: Δ, exudation clearly present: x was visually judged. Two types of evaluation were performed on the entire surface and around the hole with a radius of 2 cm.
(8-3) Wrinkles were not generated on the reinforcing material surface of the molded product: ○, fine wrinkles were generated: Δ, wrinkles were generated: x was visually determined.
(8-4) Floating No lifting occurred on the reinforcing material surface of the molded product: ○, Micro-floating: Δ, Floating: X was judged by visual and tactile sensation.
(8-5) Tearing No tearing on the reinforcing material surface of the molded product: ○, Immediately before tearing: Δ, There was tearing: x was visually judged.
(8-6) Peeling When separating the reinforcing material surface of the molded product from the foam, the edge of the reinforcing material of the molded product is peeled 1 cm, and the reinforcing material is torn by hand from the foam. The boundary does not peel: ○, peeling close to the boundary peeling occurs: Δ, peeling at the boundary: x

(9) Performance Evaluation of Molded Product (9-1) Sound Suppression Hearing rubbing sound when pressing the molded product obtained in (8) so that the thickness is halved, no sound can be heard: ○, sound slightly only at the moment of compression: Δ, sound at compression and recovery: ×, sensory evaluation.
(9-2) Abrasion resistance Using the method defined in JIS L 0849 using a sample obtained by slicing the reinforcing material surface side of the molded product obtained in (8) into a thickness of 5 mm including the foam. Using a friction tester type II (Gakushin type), the reinforcing material surface was set as a friction surface, worn for 10 minutes, and the degree of damage was classified by visual judgment and evaluated. No damage: 5, Minor damage: 4, Little damage: Grade 3, Damage moderate: Grade 2, Damage large: Grade 1.
(9-3) Shape retention The molded product obtained in (8) is placed on a 55 cm square 10 mm iron plate, and the height at which the same iron plate is joined to the load cell with Tensilon (Baldwin UCT25T) is Hcm. Then, compression recovery (50% repetitive compression) was repeated 100 times to half the height, and the damage state of the reinforcing material surface was visually judged and the following evaluation was performed. ○: Damage, no peeling, Δ: Small peeling, no damage, ×: Peeling, damaged

(10) Flame retardance Measurement was performed according to FMVSS302. The short fiber non-woven fabric may vary greatly depending on the location, and measurement was performed at 5 locations evenly divided in the width direction.

<Example 1>
A short fiber made of polyethylene terephthalate having a solid structure of 2.2 dtex (unitika Ltd. 100, cut length 51 mm), a low melting point PET whose sheath component of 4.4 dtex is a copolymer component of isophthalic acid, and a core component is After obtaining a web in which PET core-sheath type composite fiber (EE7 manufactured by Toyobo Co., Ltd., cut length 51 mm) was mixed at a weight ratio of 70:30, a needle using an organ FPD1-40S needle was used. Needle punching was performed at a piercing density (protrusion density) of 45 pieces / cm ² and a needle depth of 10 mm. Next, partial fiber adhesion was formed by passing through an oven with a total length of 7 m in an atmosphere of 150 ° C. at a speed of 5 m / min by the air-through method. Furthermore, using a facing heating roller, a non-woven fabric having a basis weight of 100 g / m ² and a thickness of 1.29 mm is processed at a roller temperature of 100 ° C., a linear pressure of 30 N / m, a processing speed of 20 m / min, and a clearance of 1 mm. Obtained. The surface of the non-woven fabric was dotted with portions where protruding fibers remained by needle punching and portions where the heat-bonding composite fibers were melted to form partial crimp joints.
Table 1 shows the evaluation results using the obtained nonwoven fabric structure.
Example 1 satisfies the requirements of the present invention, shows excellent moldability with good setability, bleeding, wrinkles, floats, tears, and peeling. Also in the performance evaluation of the molded product, the sound damping property, wear resistance, A molded product showing good performance in terms of formability was obtained.

<Example 2>
Weight of short fibers made of polyethylene terephthalate with a solid structure of 2.2 dtex, core-sheath type composite fiber (FRS manufactured by Toyobo Co., Ltd., cut length 44 mm) whose sheath component of 2.2 dtex is polyethylene and whose core component is PET After obtaining a web that was mixed in a ratio of 80:20, needle punching density (protrusion density) of 40 needles / cm ² and needle depth of 8 mm using an organ FPD1-40S needle was laminated. A nonwoven fabric structure was obtained. Next, partial fiber adhesion by passing through an oven with a total length of 7 m at a speed of 5 m / min in an atmosphere of 140 ° C. while sandwiched between Teflon (registered trademark) coated nets by the air-through method. To obtain a nonwoven fabric having a basis weight of 110 g / m ² and a thickness of 1.55 mm.
Table 1 shows the results of evaluation using the obtained nonwoven fabric structure.
Example 2 satisfies the requirements of the present invention, shows excellent moldability with good setability, exudation, wrinkles, floats, tears, and exfoliation. A molded product showing good performance in terms of formability was obtained.

<Reference example>
Polyethylene terephthalate (hereinafter abbreviated as PET) with an intrinsic viscosity of 0.65, melt-spun at a spinning temperature of 283 ° C., taken up at a spinning speed of 4800 m / min, and shaken down on a net conveyor to produce 3.3 dtex long fibers A web consisting of Subsequently, using a circular pattern embossing roller with a crimping area ratio of 15%, the nonwoven fabric A having a basis weight of 40 g / m ² was obtained by processing at a roller temperature of 170 ° C., a linear pressure of 30 N / m, and a processing speed of 20 m / min. Similarly, a non-woven fabric B having a basis weight of 40 g / m ^{2 having} 1.7 dtex was obtained. After the nonwoven fabric A and the nonwoven fabric B are laminated so that the surface on the net conveyor side at the time of manufacturing the nonwoven fabric is the outside, needle piercing density (projection density) 49 / cm ² using needles of FPD1-40S manufactured by Organ Co., needle A laminated nonwoven fabric structure was obtained by needle punching at a depth of 12 mm.
Table 1 shows the results of evaluation using the obtained nonwoven fabric structure.
The non-woven fabric of the reference example showed good moldability in terms of setability, bleeding, floating, tearing, and peeling. Also in the performance evaluation of the molded product, a molded product showing good performance of sound damping and wear resistance was obtained. However, when the mold is deep-drawn, wrinkles are slightly more likely to occur than in the examples, and there is a case where the mold addition is not practically problematic but lacks the smoothness of a slightly steep aspect.

<Comparative Example 1>
A mixed web was obtained in the same manner as in Example 2. Subsequently, a needle punching nonwoven fabric structure was obtained with a piercing density of 85 / cm ² .
Foam evaluation was carried out as it was without air-through treatment. Urethane exudation occurred from the gaps in the fibers, and friction noise was generated when the molded product was compressed. There was also a problem with the sound control. The tear strength after impregnation with urethane was low, and strong rubbing against the processing burr of the S-spring caused the sheet to break, which was a problem. Moreover, when Thomson blade punching was performed together with the mold, a large amount of fiber waste was generated, which was a problem. When the flame retardancy was evaluated with the reinforcing material alone, two of the five locations failed FMVSS302.

<Comparative example 2>
A mixed web was obtained in the same manner as in Example 2. However, a non-woven fabric structure is formed by air-through treatment so as to form a partial fiber bond by passing through an oven with a total length of 7 m in an atmosphere of 140 ° C. at a speed of 5 m / min without performing the needle punch method. Got the body.
The obtained non-woven fabric was inferior in mechanical properties and had a practical problem.
As a result of foaming evaluation, bleeding occurred during urethane foaming, and frictional noise was generated when the molded product was compressed. When the flame retardancy was evaluated with the reinforcing material alone, the total number of 5 locations failed FMVSS302.

The nonwoven fabric for foam-molded reinforcing material of the present invention is excellent in bleeding prevention properties, installation handling properties, processability, and molded product quality even at a low basis weight. In other words, the non-woven fabric for reinforcing material is not too hard and not too soft, and it can be attached to the molding frame well, and has good followability and good air permeability even in deep drawing molding at low temperature foaming typified by cold foaming. Occasionally wrinkles, thinning and resin loss can be prevented, and the non-woven fabric for reinforcing material becomes a molded product that is firmly bonded to the foam, suppressing abrasion, bending and refraction noise, and shape retention durability and wear resistance In addition, it is possible to provide a non-woven fabric for reinforcing foam-molded products suitable for low-temperature cold foaming, which can produce a light-weight cold-foamed molded article. Moreover, it becomes possible to provide a lightweight non-woven fabric for foam molded article reinforcing material having an appropriate tear strength and flame retardancy after compounding with urethane, and a method for producing the same, which greatly contributes to the industry.

Claims (4)

A non-woven fabric used as a reinforcing material for urethane foam moldings, thickness at 7 g / cm ² load is 0.4 to 2.0 mm, tensile strength is 50 N / 5 cm or more, elongation is 100% or less, A non-woven fabric for reinforcing foamed articles comprising a short-fiber non-woven fabric having a tear strength of 20 N or more and having at least a part thermally bonded. The nonwoven fabric for reinforcing foam-molded articles according to claim 1, wherein the basis weight is 60 to 140 g / m ² , the fragile air permeability is 50 to 350 cc / cm ² / sec, and the tear strength after urethane impregnation is 18 N or more.   The main constituent fiber is a non-woven fabric made of polyester fiber having a fineness of 1.0 to 6.7 dtex, containing 5 to 50% of a composite fiber containing a low melting point component, and at least partially compressed and densified. The nonwoven fabric for foam molded article reinforcing material according to claim 1, wherein The foamed molded article reinforcement according to any one of claims 1 to 3, wherein after forming a fiber entanglement with a web made of short fibers, partial thermal adhesion is imparted between the fibers by an air-through method and further brought into contact with a heating roll. The manufacturing method of the nonwoven fabric for materials.