JP2005288873A - Reinforcing material used for foam molding of urethane resin and molded article of urethane foam molding with reinforcing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reinforcing material which is lightweight and can effectively suppresses oozing of a urethane resin while necessary functions as the reinforcing material used for a molded article of a urethane foam molding are provided. <P>SOLUTION: The reinforcing material 12 is integrated with a urethane foam 11 and constitutes the molded article 1 of the urethane foam molding with the urethane foam 11. The reinforcing material 12 has a bulky nonwoven fabric 13 into which the urethane resin soaks when the urethane resin is foamed, and a drawn and orthogonally intersecting nonwoven fabric 14 which is laminated on one face of the bulky nonwoven fabric 13 to suppress oozing of the urethane resin passed through the bulky nonwoven fabric 13. The drawn and orthogonally intersecting nonwoven fabric 14 has a basis weight of 10-40 g/m<SP>2</SP>, a Frazier gas permeability of 50-500 cm<SP>3</SP>/cm<SP>2</SP>sec. The Frazier gas permeability of the whole reinforcing layer 12 is 10-300 cm<SP>3</SP>/cm<SP>2</SP>sec. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reinforcing material used for foam molding of urethane resin, and a urethane foam molded product molded using the reinforcing material.

  As cushion materials for vehicle seats and sofas, foam molded products such as soft polyurethane are generally used. In this type of foam-molded product, when used as a cushion, it is not damaged by the pressing force of the spring attached to the lower part, and it is stiffened so that it has rigidity and good cushioning properties. Is used. And, as a method of manufacturing a foam molded article using a reinforcing material, first, the reinforcing material is installed in contact with the inner surface of the mold for foam molding, and in that state, a liquid urethane resin is injected into the mold, There is a method of foaming by heating and pressing.

  The reinforcing material is impregnated with the urethane resin foamed in the mold and integrated, but if the impregnated urethane resin oozes out from the reinforcing material, the oozing urethane resin hardens and is otherwise used as a product. Contact with the metal parts (for example, the above-mentioned springs and frames), which may cause a rubbing sound due to friction. Therefore, in addition to the function of impregnating the urethane resin, the reinforcing material is required to have a function of preventing the impregnated urethane resin from bleeding from the surface.

  As such a reinforcing material, for example, in Patent Document 1 and Patent Document 2, at least one nonwoven fabric layer and a reticulated base material layer are provided with air permeability by a needle punching method, a thermal lamination method, or the like. An integrated foam molding reinforcement is disclosed. As the reticulated base material layer, a uniaxially stretched body (split web, slit web, uniaxially stretched tape) formed from a thermoplastic resin film is used which is laminated or woven so that the stretch axes intersect. In the foam molding of the urethane resin, the reinforcing material is placed with the nonwoven fabric layer in close contact with the inner surface of the mold, and the urethane resin is injected into the mold in that state.

The reinforcing materials disclosed in Patent Documents 1 and 2 use a reticulated base material layer, thereby ensuring the necessary strength and permeability of the urethane resin, and preventing the urethane resin from seeping out by the outer nonwoven fabric layer. ing. As a result, the reinforcing effect is excellent, and the urethane resin oozes out to the surface at the time of molding, and a cured product is not generated, and a rubbing sound due to friction with other metal parts is prevented.
JP 2000-31080 A JP 2000-313081 A

As described above, the conventional reinforcing material is excellent in the reinforcing effect of the urethane foam molded article and the permeability of the urethane resin. Therefore, in order to effectively prevent the urethane resin from seeping out from the surface, it is necessary to increase the basis weight of the nonwoven fabric layer. Specifically, in the reinforcing material having the configuration disclosed in Patent Documents 1 and 2, in order to reliably prevent the urethane resin from bleeding, the nonwoven fabric layer has a basis weight of about 80 to 140 g / m ^2. Used.

  On the other hand, when the urethane foam molded article is used for a vehicle seat such as an automobile, weight reduction is an important issue. Therefore, weight reduction is demanded not only for urethane foam but also for this reinforcing material.

  Therefore, the present invention provides a reinforcing material that has a function necessary as a reinforcing material used in a urethane foam molded article, is lightweight and can effectively suppress the seepage of urethane resin, and a urethane foam molded article using the same. The main purpose is to provide.

In order to achieve the above object, the reinforcing material of the present invention is a reinforcing material that is used for foam molding of urethane resin and is provided integrally with at least a part of the surface of the urethane foam molded article, and when the urethane resin is foamed A bulky nonwoven fabric into which the urethane resin permeates and a dense nonwoven fabric laminated on one side of the bulky nonwoven fabric in order to suppress the seepage of the urethane resin that has passed through the bulky nonwoven fabric. The dense nonwoven fabric has a basis weight of 10 to 40 g / m ² , a fragile air permeability of 50 to 500 cm ³ / cm ² · sec, and a fragile air permeability of the entire reinforcing layer of 10 to 300 cm ³ / cm ² · sec. It is.

  The reinforcing material of the present invention is placed in close contact with the inner surface of the mold during foam molding of urethane resin. The foamed urethane resin penetrates into the bulky nonwoven fabric, whereby a urethane foam molded product in which the foamed urethane resin and the reinforcing material are integrated is obtained. A dense nonwoven fabric is laminated on one side of the bulky nonwoven fabric, and by setting the basis weight of the dense nonwoven fabric and the fragile air permeability within the above ranges, it is possible to effectively exude urethane resin while achieving weight reduction. At the same time as being suppressed, escape of gas generated at the time of foaming of the urethane resin can be performed well.

  The reinforcing material of the present invention may have a structure in which an outermost layer composed of a nonwoven fabric or a net-like structure is further laminated on a surface opposite to a surface laminated with a bulky nonwoven fabric of a dense nonwoven fabric. Thereby, even if the urethane resin oozes out from the laminated structure, the urethane resin that has oozed out and hardened is prevented from coming into direct contact with other components when the urethane foam molded product is used.

  The urethane foam molded article of the present invention has the above-mentioned reinforcing material of the present invention and a urethane foam formed by foaming a urethane resin, and the reinforcing material is integrated with the urethane foam through the penetration of the urethane resin. ing.

  Since the urethane foam molded article of the present invention uses the above-mentioned reinforcing material of the present invention as a reinforcing material, the urethane resin oozes from the reinforcing material while the reinforcing material and the urethane foam are integrated by penetration of the urethane resin. When the urethane foam molded product is used, it is possible to prevent the rubbing noise that is generated when the urethane resin that has oozed out from the reinforcing material and comes into direct contact with other components. Further, since the weight can be reduced as compared with the conventional reinforcing material, the urethane foam molded product can be reduced in weight by the amount that the reinforcing material is light.

  According to the reinforcing material of the present invention, gas generated at the time of foaming of the urethane resin can be released well while being lightweight and effectively suppressing the seepage of the urethane resin. As a result, the urethane foam molded product foam-molded using the reinforcing material of the present invention integrates the urethane foam and the reinforcing material by impregnating the urethane resin into the reinforcing material, while the cured urethane resin is in use. The rubbing sound generated by direct contact with other parts can be prevented, and the urethane foam can be made homogeneous. Moreover, since the reinforcing material can be made light, weight reduction of the urethane foam molded product can also be achieved.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of an essential part of a urethane foam molded product according to an embodiment of the present invention. FIG. 1 schematically shows the layer configuration, and does not necessarily match the actual cross-sectional structure.

  As shown in FIG. 1, the urethane foam molded article 1 is reinforced to reinforce the urethane foam 11 and the urethane foam 11 so that the urethane foam 11 does not directly contact other parts when the urethane foam molded article 1 is used. Material 12.

  Urethane foam is a foam made of diisocyanate and polyol. Diisocyanates include m-phenylene diisocyanate, toluene-2,4-diisocyanate, hexamethylene-1,6-diisocyanate, tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, naphthalene-1,5-diisocyanate. 1-methoxyphenyl-2,4-diisocyanate, diphenylmethane-4,4′-diisocyanate, 4,4′-biphenylene diisocyanate, and the like.

  Examples of the polyol include a polyether type such as polyoxypropylene glycol and polyoxypropylene-polyoxyethylene glycol, and a polyester type mainly composed of condensed adivic acid and ethylene glycol. Of these, the polyether type is preferable.

  The urethane foam 11 is prepared by mixing a polyol as described above, a liquid A containing a foaming agent, a catalyst, a cell size adjusting agent, etc., and a liquid B containing isocyanate as a main component in a short time. It can be molded by a so-called reaction injection molding method (RIM) in which a liquid is injected into a mold from a nozzle to form a foam.

  The reinforcing material 12 is placed in close contact with the inner surface of a foam molding die during foam molding of the urethane foam 11, and is a bulky nonwoven fabric 13 and a dense nonwoven fabric laminated on one side thereof. Of the stretched orthogonal nonwoven fabric 14. The bulky nonwoven fabric 13 is disposed on the urethane foam 11 side, and has a function of impregnating the urethane resin foamed in the mold. The stretched orthogonal nonwoven fabric 14 has a function of preventing the urethane resin that has passed through the bulky nonwoven fabric 13 from oozing out from the reinforcing material 12.

  Below, the bulky nonwoven fabric 13 and the stretched orthogonal nonwoven fabric 14 are demonstrated.

The bulky nonwoven fabric 13 is not particularly limited as long as it can be impregnated with urethane resin. However, in order to satisfactorily impregnate the urethane resin, the basis weight is preferably 30 to 70 g / m ² . If the basis weight of the bulky nonwoven fabric 13 is less than 30 g / m ² , the urethane resin may excessively permeate into the bulky nonwoven fabric 13 and ooze out from the stretched orthogonal nonwoven fabric 14. On the other hand, when the weight per unit area exceeds 70 g / m ² , the urethane resin is less likely to penetrate and the urethane foam 11 and the reinforcing material 12 may not be sufficiently integrated, and the mold becomes thicker. Curved surface followability when installed on the inner surface is reduced. In general, the basis weight of the nonwoven fabric is approximately proportional to the thickness. For example, in a spunbonded nonwoven fabric made of polyethylene terephthalate (PET), the basis weight of 30 to 70 g / m ² is about 0. 2 to 0.65 mm.

  Examples of the nonwoven fabric preferably used as the bulky nonwoven fabric 13 in the present invention include a needle punched nonwoven fabric and a spunlace nonwoven fabric. These nonwoven fabrics can be combined and integrated with the stretched orthogonal nonwoven fabric 14 in the manufacturing process, and do not require a process such as thermal bonding for combining and integrating the two. Thereby, the manufacturing process of the reinforcing material 12 can be reduced, and the manufacturing cost can be reduced. If the bulky nonwoven fabric 13 and the stretched orthogonal nonwoven fabric 14 may be combined and integrated separately, the bulky nonwoven fabric 13 may include a spunbond nonwoven fabric in addition to the needle punch nonwoven fabric and the spunlace nonwoven fabric. It can also be used.

  As shown in the cross-sectional view of FIG. 2, the stretched orthogonal nonwoven fabric 14 includes two stretched unidirectionally aligned nonwoven fabrics 14 a and 14 b in which filaments (fibers) are arranged in approximately one direction and are stretched in the filament arrangement direction. Is a non-woven fabric in which the arrangement directions of the filaments are orthogonal to each other.

  The stretched unidirectionally aligned non-woven fabrics 14a and 14b are obtained by stretching filaments in the array direction, and in the spinning stage, a filament having a fineness (thickness) of 2 to 3 dTex is spun in the same manner as a normal non-woven fabric. The fineness of the stretched unidirectionally arranged non-woven fabrics 14a and 14b is 1.5 dTex or less by stretching this 5 to 10 times in the filament arranging direction. In this case, since the filaments are unoriented at the spinning stage and the accumulated filaments are arranged in a certain direction, even if the filaments have a small fineness, in other words, a thin filament, by stretching in the filament arrangement direction. The tensile strength after stretching is improved. However, since the filament arrangement at the spinning stage is not perfect, the stretched unidirectionally aligned nonwoven fabrics 14a and 14b are slightly mixed with unstretched filaments and unoriented filaments, and mainly stretched unidirectionally aligned with a fineness of 1.5 dTex or less. It becomes the nonwoven fabric 14a, 14b. Since the unstretched filament has a low melting point and melts in the subsequent lamination process, it functions as an adhesive between the filaments of the stretched unidirectionally aligned nonwoven fabrics 14a and 14b.

  The filaments constituting the stretched unidirectionally arranged nonwoven fabrics 14a and 14b are long fiber filaments. The long fiber filament referred to here may be a substantially long fiber and has an average length exceeding 100 mm. When the diameter of the filament is 50 μm or more, it is rigid and entanglement becomes insufficient. Therefore, it is desirably 30 μm or less, and more desirably 25 μm or less. In particular, when a non-woven fabric with high strength is intended, the filament diameter is desirably 5 μm or more. The length and diameter of the filament are measured by a micrograph.

  The stretched unidirectionally aligned nonwoven fabrics 14a and 14b include a longitudinally stretched nonwoven fabric and a laterally stretched nonwoven fabric depending on the manufacturing method thereof. In the present embodiment, any of these can be used, and the combination is also free. The longitudinally stretched nonwoven fabric is a nonwoven fabric in which filaments are arranged and stretched in the longitudinal direction, which is the feed direction when producing the nonwoven fabric, and the transversely stretched nonwoven fabric is a direction perpendicular to the feed direction when producing the nonwoven fabric. A nonwoven fabric in which filaments are arranged and stretched in the transverse direction.

  The longitudinally stretched nonwoven fabric and the laterally stretched nonwoven fabric will be described in detail.

  The longitudinally stretched non-woven fabric gives draft tension to the spun filament to reduce the filament diameter, and then accumulates on the conveyor by using the movement of the conveyor to form a web in which the filaments are arranged in the longitudinal direction. This is obtained by stretching in the longitudinal direction.

  Examples of a method for giving draft tension to the filament include a melt blow method (MB method) and a narrowly defined spunbond method (SB method). In any method, hot air is sprayed onto the filament in order to minimize molecular orientation when reducing the diameter of the filament. In addition, in order to improve the arrangement of the filaments on the conveyor, the filament is spun while being inclined with respect to the conveyor conveying surface, or a rod member is arranged in the hot air flow area, and the rod member is rotated or moved. It is preferable to vibrate the filament in the longitudinal direction using the Coanda effect generated by the above.

  The web accumulated on the conveyor is stretched in the longitudinal direction to form a longitudinally stretched nonwoven fabric.

  Although the web may be fully stretched in one stage, multistage stretching is mainly used. In multistage stretching, the first stage of stretching is performed as preliminary stretching immediately after spinning, and the second and subsequent stages of stretching are performed as main stretching.

  As a web stretching method, a proximity stretching method is preferably used. When the proximity stretching method is used in the multistage stretching, the proximity stretching is used for the first stage stretching. The proximity stretching method is a method of stretching while maintaining a short distance between stretches (distance from the starting point of stretching to the end point) in a method of stretching the web by the difference in surface speed between two adjacent sets of rolls, It is desirable that the distance between stretching is 100 mm or less. Thus, individual filaments can be effectively stretched by stretching the web by the proximity stretching method. In particular, when the filaments are arranged in the longitudinal direction as a whole but are bent to some extent, keeping the distance between the draws as short as possible is important for effectively drawing the individual filaments.

  In a general melt blown nonwoven fabric, filaments are randomly arranged, and even if the filaments are stretched by the proximity stretching method, the probability that individual filaments are stretched is low only by increasing the spacing between the filaments. However, in the present invention, since the webs are already arranged in one direction at a high degree, according to the proximity drawing method, individual filaments can be drawn more reliably.

  Next, the transversely stretched nonwoven fabric will be described. In order to produce a transversely stretched nonwoven fabric, first, a web in which filaments are arranged in the transverse direction is formed. The web in which the filaments are arranged in the horizontal direction is obtained by shaking the filaments spun from the spinning nozzles in the horizontal direction by directly ejecting air from the air ejection holes arranged around the spinning nozzles and collecting them on the conveyor. Can be formed. As another method, there is a method in which the filaments are vibrated in the lateral direction using the Coanda effect described above and accumulated on a conveyor. In this way, the filaments are accumulated on the conveyor in a state where there are many arrangement components in the lateral direction.

  By stretching the web thus obtained in the filament arrangement direction, that is, in the transverse direction, a transversely stretched nonwoven fabric is obtained.

  Examples of the method of stretching the web in the transverse direction include a tenter method and a pulley method. The tenter method is generally used as a method for widening a film or the like, but requires a large floor area for installation of equipment, and it is difficult to change the product width and the magnification ratio. The stretch ratio of the nonwoven fabric must be changed according to the application. Therefore, it is preferable to use a pulley system in which these changes can be easily performed even during operation.

  The representative production method of the stretched unidirectionally aligned nonwoven fabrics 14a and 14b has been described by taking the longitudinally stretched nonwoven fabric and the laterally stretched nonwoven fabric as examples. However, the production method of the stretched unidirectionally aligned nonwoven fabrics 14a and 14b is limited to the method described above. Any method can be used as long as the filaments are arranged substantially in one direction and the arranged filaments can be drawn in the arrangement direction.

  The thermoplastic resin constituting the stretched unidirectionally arranged nonwoven fabrics 14a and 14b is used as a flat yarn or industrial material fiber such as polyolefin such as high density polyethylene and polypropylene, nylon, polyester, polyvinyl alcohol, polyacrylonitrile and the like. Resin. Among these, polypropylene and polyester are particularly excellent in terms of cost and handling.

  The longitudinally stretched nonwoven fabric and the laterally stretched nonwoven fabric described above are desirably used as they are as one stretched unidirectionally aligned nonwoven fabric 14a and the other stretched unidirectionally aligned nonwoven fabric 14b, respectively. As a result, the two stretched unidirectionally aligned nonwoven fabrics 14a and 14b are continuously drawn out and overlapped, and a continuous uniform stretched orthogonal nonwoven fabric 14 without a joint can be obtained. In addition, a longitudinally stretched nonwoven fabric is prepared in advance, and at the production stage of the laterally stretched nonwoven fabric, the longitudinally stretched nonwoven fabric is drawn out and stacked on the laterally stretched nonwoven fabric in the course of transporting the laterally stretched nonwoven fabric, and these are laminated, thereby stretching 14 can be manufactured more efficiently.

  The two stretched unidirectionally arranged nonwoven fabrics 14a and 14b can be laminated by, for example, a hot embossing method. The embossing conditions vary depending on the type of resin used for the stretched unidirectionally aligned nonwoven fabrics 14a and 14b, but are preferably 30 to 80 ° C. lower than the melting point. Moreover, when high surface smoothness is requested | required of the extending | stretching orthogonal nonwoven fabric 14, lamination | stacking of the two extending | stretching one way arrangement | sequence nonwoven fabrics 14a and 14b can also be performed by a thermal calendar process.

  As described above, when the bulky nonwoven fabric 13 is composed of a needle punched nonwoven fabric or a spunlace nonwoven fabric, the bulky nonwoven fabric 13 and the stretched orthogonal nonwoven fabric 14 are laminated while supplying the stretched orthogonal nonwoven fabric 14 in the manufacturing process of the bulky nonwoven fabric 13. By doing so, the stretched orthogonal nonwoven fabric 14 can be laminated simultaneously with the production of the bulky nonwoven fabric 13. Moreover, when laminating | stacking the bulky nonwoven fabric 13 produced previously with the extending | stretching orthogonal nonwoven fabric 14, the bulky nonwoven fabric 13 and the extending | stretching orthogonal nonwoven fabric 14 can be laminated | stacked using heat, such as a thermocompression bonding method.

  Using the reinforcing material 12 described above, the urethane foam molded article 1 can be manufactured as follows, for example. First, the reinforcing material 12 is disposed in close contact with the inner surface of a urethane foam molding die. At this time, the stretched orthogonal nonwoven fabric 14 is arranged toward the inner surface of the mold. Thereafter, the mold is closed and urethane resin is injected into the mold, and the urethane resin is heated and pressurized in the mold to foam the urethane resin. At this time, the foamed urethane resin penetrates into the reinforcing material 12, but the reinforcing material 12 has a two-layer structure of a bulky nonwoven fabric 13 and a stretched orthogonal nonwoven fabric 14, and the penetrated urethane resin is stretched for the reasons described below. It does not ooze out from the orthogonal nonwoven fabric 14. And after hardening of a urethane resin, a metal mold | die is opened and the obtained urethane foam molded product 1 is taken out. The urethane foam molded article 1 has a configuration in which the reinforcing material 12 is integrated with the urethane foam 11 as shown in FIG.

  The reinforcing material 12 uses a stretched orthogonal nonwoven fabric 14, but the stretched orthogonal nonwoven fabric 14 has a unique structure in which two stretched unidirectionally aligned nonwoven fabrics 14 a and 14 b are laminated so that the filament arrangement directions are orthogonal to each other. And the filaments constituting the stretched unidirectionally arranged nonwoven fabrics 14a and 14b are reduced in diameter by stretching.

  Therefore, the stretched orthogonal nonwoven fabric 14 has a dense structure as compared with a commonly used nonwoven fabric, and effectively suppresses the seepage of the urethane resin from the reinforcing material 12 that has passed through the bulky nonwoven fabric 13 during foaming of the urethane resin. it can. As a result, in the urethane foam molded article 1, the urethane resin seepage from the reinforcing material 12 is suppressed, so that when the urethane foam is used as a cushion for a vehicle seat, for example, the cured urethane resin is urethane foam molded. There is no direct contact with other parts such as a spring and a frame arranged in contact with the product 1, and the generation of rubbing noise between the urethane foam molded product 1 and the other components can be prevented.

  Moreover, since the stretched unidirectionally arranged nonwoven fabrics 14a and 14b have a dense structure as described above and the tensile strength is improved by stretching, the mechanical strength necessary as the reinforcing material 12 is low even if the basis weight is low. And the above-described seepage of the urethane resin can be effectively suppressed. By reducing the weight of the stretched orthogonal nonwoven fabric 14 that prevents the seepage of the urethane resin, the overall weight of the reinforcing material 12 can be reduced as a result. Moreover, weight reduction of the urethane foam molded product 1 can also be achieved by achieving weight reduction of the entire reinforcing material 12.

The effect of preventing the urethane resin from bleeding depends on the basis weight of the stretched orthogonal nonwoven fabric 14. In order to suppress the seepage of the urethane resin more effectively, the basis weight of the stretched orthogonal nonwoven fabric 14 is set to 10 to 40 g / m ^{2 in} the present invention. When the weight per unit area of the stretched orthogonal nonwoven fabric 14 is less than 10 g / m ^2, it is difficult to sufficiently suppress the seepage of the urethane resin, and it is difficult to produce a nonwoven fabric having such a weight per unit area without unevenness. On the other hand, it is preferable that the basis weight is high in order to suppress the seepage of the urethane resin, but the basis weight is sufficient if it is 40 g / m ² . It becomes an obstacle. In addition, an excessively high basis weight may cause another problem as described below. The basis weight 40 g / m ² of the stretched orthogonal nonwoven fabric 14 is about 0.15 mm in terms of thickness.

  As described above, an important characteristic of the reinforcing material 12 used in the urethane foam molded article 1 is to suppress the seepage of the urethane resin. The reinforcing material 12 has another important characteristic for foaming the urethane resin. That is to release the gas generated when the urethane resin is foamed. That is, the reinforcing material 12 needs to release the generated gas at the same time as suppressing the seepage of the urethane resin. Therefore, it is important that the reinforcing material 12 not only suppresses the seepage of the urethane resin but also has an appropriate air permeability for releasing the generated gas.

The fragile air permeability measured according to JIS L 1096 can be used as an index indicating the characteristic of suppressing the seepage of the urethane resin and allowing the gas generated during foaming to escape. According to the experiments by the present inventors, the fragile air permeability of the reinforcing material 12 used for urethane foam molding is 10 to 300 cm ³ / cm ² · sec, preferably 100 to 200 cm ³ / cm ² · sec.

Furthermore, in the present invention, the stretched orthogonal nonwoven fabric 14 used as the dense nonwoven fabric for suppressing the seepage of the urethane resin also has a fragile air permeability of 50 to 500 cm ³ / cm ² · sec. Since the stretched orthogonal nonwoven fabric 14 is a dense nonwoven fabric as described above, if the stretched orthogonal nonwoven fabric 14 is within the range of the basis weight of 10 to 40 g / m ² , this Frazier air permeability can be sufficiently satisfied. .

  If the above-described air permeability is insufficient, outgassing is not uniform in the vicinity of the reinforcing material 12. As a result, poor foaming of the urethane resin occurs at a portion where gas is difficult to escape, and a uniform foam cannot be obtained. When the non-uniformity of outgassing is extreme, the foaming reaction itself does not occur and an unreacted part may occur. On the other hand, if the air permeability is too high, the outgassing is good, but the permeability of the urethane resin also becomes high, and the exudation of the urethane resin cannot be sufficiently suppressed.

  Thus, it is important to define the air permeability from the viewpoint of outgassing and foaming suppression during urethane resin foam molding, but a low-weight nonwoven fabric, that is, a stretched orthogonal nonwoven fabric 14 is used as a layer for suppressing the bleeding. When using, it is necessary to define not only the air permeability of the entire reinforcing material 12 but also the air permeability of the stretched orthogonal nonwoven fabric 14. Even if the air permeability of the entire reinforcing material 12 satisfies the above range and the gas releasing property is good, if the stretched orthogonal nonwoven fabric 14 does not have a predetermined air permeability, it is effective for the urethane resin to exude. This is because sometimes it cannot be suppressed.

As a result of intensive studies by the present inventors, the fragile air permeability of the entire reinforcing material 12 is set to 10 to 300 cm ³ / cm ² · sec, and the fragile air permeability of the stretched orthogonal nonwoven fabric 14 is 50 to 500 cm ³ / cm ² · sec. By doing so, it is possible to obtain a reinforcing material 12 that has good gas escape during urethane foam molding and can effectively suppress the seepage of the urethane resin. In particular, the stretched orthogonal nonwoven fabric 14 has a configuration in which two nonwoven fabrics made of fine fibers arranged in one direction at a high degree are laminated so that the fiber alignment directions are orthogonal to each other. As the most appropriate.

  In the example shown in FIG. 1, the urethane foam molded product 1 in which the reinforcing material 12 is provided only on a part (one side) of the surface of the urethane foam 11 is shown. However, the reinforcing material 12 is a urethane foam molded product. The reinforcing material 12 can be provided so as to cover the entire surface of the urethane foam, for example, as shown in FIG. The urethane foam molded article 1 as shown in FIG. 1 can be manufactured by installing a reinforcing material 12 on a part of the inner surface of the mold. The urethane foam molded article 1 as shown in FIG. It can manufacture by installing the reinforcing material 12 in the whole.

  Moreover, although the example which distribute | arranged the bulky nonwoven fabric 13 to the urethane foam 11 side was shown in the example mentioned above, the extending | stretching orthogonal nonwoven fabric 14 can also be distribute | arranged to the urethane foam 11 side. In this case, since the urethane resin is in direct contact with the orthogonally stretched nonwoven fabric 14, a larger amount of urethane resin permeates than the bulky nonwoven fabric 13 and oozes out into the bulky nonwoven fabric 13. However, if the weight per unit area and the fragile air permeability of the orthogonal stretch nonwoven fabric 14 and the fragile air permeability of the entire reinforcing material 12 are set within the above ranges, the exudation to the bulky nonwoven fabric 13 is limited by the orthogonal stretch nonwoven fabric 14. Therefore, further oozing from the bulky nonwoven fabric 13 can be suppressed.

  Although the two-layer reinforcing material 12 has been described above, a three-layer structure may be used as shown in FIG. In the urethane foam molded article 20 shown in FIG. 4, a reinforcing material 22 in which an outermost layer 25 is further laminated outside the stretched orthogonal nonwoven fabric 24 is used. In FIG. 4, the reinforcing material 22 is provided on a part of the surface of the urethane foam 21. Of course, as in the case shown in FIG. 3, the reinforcing material 22 may be provided to cover the entire surface of the urethane foam 21. it can.

  Hereinafter, the reinforcing material 22 shown in FIG. 4 will be described. However, since the bulky nonwoven fabric 23 and the stretched orthogonal nonwoven fabric 24 can be the same as those described above, these descriptions are omitted, and only the outermost layer 25 is used. Will be explained.

  The stretched orthogonal nonwoven fabric 24 is provided to prevent the urethane resin from oozing out. However, depending on the foaming conditions, the urethane resin cannot be reliably oozed out and may ooze out slightly. is there. Even when the urethane resin oozes out of the stretched orthogonal nonwoven fabric 24 in this way, the outermost layer 25 is in contact with other parts when the urethane foam molded product 20 is used. Is provided in order to prevent rubbing noise more reliably.

  Since most of the urethane resin seepage is suppressed by the stretched orthogonal nonwoven fabric 24, the outermost layer 25 does not need the urethane resin seepage suppressing performance as much as the stretched orthogonal nonwoven fabric 24, and more than necessary. The suppression performance makes it difficult to escape the gas generated when the urethane resin is foamed. Therefore, as the outermost layer 25, the same nonwoven fabric as the bulky nonwoven fabric 23 or a network structure layer can be used as long as the thickness of the entire reinforcing material 22 does not become too thick.

  The network layer is a layer formed into a network structure by appropriately combining a uniaxially stretched split fiber film, a uniaxially stretched slit film, or a tape made from a uniaxially stretched film, and has a high mechanical strength with a thin thickness by being stretched. And sufficient air permeability.

  FIG. 5 shows a plan view of an example of the network structure layer 31. The network structure layer 31 shown in FIG. 5 is obtained by laminating two uniaxially stretched split fiber films 41 by thermal fusion.

  FIG. 6 shows an enlarged perspective view of the uniaxially stretched split fiber film 41. As shown in FIG. 6A, the uniaxially stretched split fiber film 41 is a second thermoplastic resin having a melting point lower than that of the first thermoplastic resin on both sides of the layer 41a made of the first thermoplastic resin. As shown in FIG. 6A, a plurality of trunk fibers 42 that extend in parallel to each other and the trunk fibers 42 that extend adjacent to each other and intersect with the trunk fibers are adjacent to each other. It is comprised with the branch fiber 43 which connects each other. The branch fibers 43 are thinner than the trunk fibers 42, and the mechanical strength of the uniaxially stretched split fiber film 41 is mainly provided by the trunk fibers 42.

  The thickness of the layer 41b made of the second thermoplastic resin is 50% or less, desirably 40% or less, of the total thickness of the uniaxially stretched split fiber film 41. In order to satisfy various physical properties such as adhesive strength at the time of heat fusion between the uniaxially stretched split fiber films 41, the thickness of the layer 41b made of the second thermoplastic resin may be 5 μm or more, preferably 10 It is selected from the range of ˜100 μm.

  As a manufacturing method of the uniaxially stretched split fiber film 41, the method as shown below is mentioned, for example.

  First, an original film having a three-layer structure in which layers 41b made of a second thermoplastic resin are laminated on both surfaces of a layer 41a made of a first thermoplastic resin by extrusion molding such as a multilayer inflation method or a multilayer T-die method. Manufacturing. Next, as shown in FIG. 7, the original film 40 is split in a vertical direction (L direction shown in FIG. 7) in a zigzag manner using a splitter (slit treatment), or slitted with a hot blade. To form a large number of parallel slits 40a, which are further stretched in the vertical direction and widened in a direction perpendicular thereto. Thereby, as shown in FIG. 6, the uniaxially stretched split fiber film 41 in which the trunk fibers 42 are arranged substantially in the longitudinal direction is obtained.

  The draw ratio (orientation ratio) is preferably 1.1 to 15 times, more preferably 3 to 10 times. If the draw ratio is less than 1.1 times, the mechanical strength may not be sufficient. On the other hand, when the draw ratio exceeds 15 times, it is difficult to draw by a usual method, and problems such as the need for an expensive apparatus arise. Stretching is preferably performed in multiple stages in order to prevent stretching unevenness.

  Finally, the uniaxially stretched split fiber film 41 obtained as described above is overlapped so that the stretching directions are orthogonal to each other, and this is heated and fused to form a mesh shape as shown in FIG. A structural layer 31 is obtained. At the time of heat fusion, the superposed uniaxially stretched split fiber film 41 is supplied between a pair of opposed heating cylinders and fixed so as not to shrink in the width direction, and the first thermoplastic resin is used. In order not to lose the stretching effect of the layer 41a made of, heat fusion is performed at a temperature not higher than the melting point of the first thermoplastic resin and not lower than the melting point of the second thermoplastic resin.

  The thickness of the network structure layer 31 is preferably 100 μm to 300 μm. More preferably, it is 150 micrometers-250 micrometers. Since the uniaxially stretched split fiber film 41 constituting the network structure layer 31 is stretched in one direction, it has sufficient strength even at this thickness.

  For example, a typical example of the network structure layer 31 obtained by orthogonally laminating two uniaxially stretched split fiber films 41 is Nisseki Warif (registered trademark), which is a split fiber nonwoven fabric manufactured by Nippon Oil Plast Co., Ltd. .

  FIG. 8 is a partial perspective view of a uniaxially stretched slit film 45 that can be used for the network structure layer. The uniaxially stretched slit film 45 can be made from the same raw fabric film used for manufacturing the uniaxially stretched split fiber film 41 shown in FIG. That is, as shown in FIG. 8, the uniaxially stretched slit film 45 includes a layer 45a made of the first thermoplastic resin, and a second melting point lower than that of the first thermoplastic resin laminated on both surfaces thereof. And a layer 45b made of a thermoplastic resin. And what stretched or slit-processed the raw film which has the layer structure in the horizontal direction (arrow T direction shown in FIG. 8) in a zigzag form is extended in the horizontal direction, and this is extended in the vertical direction. Thus, a uniaxially stretched slit film 45 having a network structure and mainly high tensile strength in the transverse direction is obtained.

  The obtained uniaxially stretched slit film 45 is superposed and heat-sealed so that the stretching directions are orthogonal to each other, thereby forming a network structure layer. Alternatively, the network structure layer can also be obtained by combining the uniaxially stretched split fiber film 41 shown in FIG. 6 and heat-sealing the uniaxially stretched split fiber film 41 and the uniaxially stretched slit film 45 so that the stretching directions are orthogonal to each other. Can be configured.

  Examples of the resin constituting the uniaxially stretched split fiber film 41 and the uniaxially stretched slit film 45 include polyolefins such as polyethylene and polypropylene and copolymers thereof, polyesters such as polyethylene terephthalate and polybutylene terephthalate, and copolymers thereof, Examples thereof include polyamides such as nylon 6 and nylon 66 and copolymers thereof, polymers and copolymers of polyvinyl chloride, methacrylic acid or derivatives thereof, polystyrene, polysulfone, polytetrachloroethylene polycarbonate, polyurethane and the like. Among these, polyolefins having good splitting properties and polymers thereof, polyesters and polymers thereof are preferable. Further, the difference in melting point between the first thermoplastic resin and the second thermoplastic resin is required to be 5 ° C. or more, and preferably 10 to 50 ° C. for manufacturing reasons.

  As described above, an example in which a network structure layer is configured by laminating two films each formed in a net shape is shown. In addition to this, a nonwoven fabric 47 made of a uniaxially stretched multilayer tape 48 as shown in FIGS. Or woven fabric 49 can also be used. The nonwoven fabric 47 and the woven fabric 49 are 1.1 to 15 times, preferably 3 to 10 times, the same raw film as that used to produce the uniaxially stretched split fiber film 41 shown in FIG. And then uniaxially stretched, and then uniaxially stretched multi-layer tape 48 cut along the stretching direction with a width of 2 mm to 7 mm. The raw film may be cut before stretching. The nonwoven fabric 47 shown in FIG. 9 is obtained by laminating a plurality of uniaxially stretched multilayer tapes 48 in parallel at regular intervals, and laminating them in two layers so that the longitudinal directions of the uniaxially stretched multilayer tapes 48 are orthogonal. A woven fabric 49 shown in FIG. 10 is obtained by weaving the uniaxially stretched multilayer tape 48 vertically and horizontally.

  In addition to each structure described above, the network structure layer includes a laminate obtained by laminating a uniaxially stretched split fiber film or a uniaxially stretched slit film and a uniaxially stretched multilayer tape so that the stretching directions are orthogonal, and a thermoplastic resin. It is also possible to use a woven fabric or a non-woven fabric in which the spun and stretched filaments are combined so that the stretching directions are orthogonal. Furthermore, the woven fabric and nonwoven fabric described above can be made not only from a uniaxially stretched multilayer tape but also from a stretched yarn spun from a thermoplastic resin such as polyethylene or polypropylene.

  Hereinafter, specific examples of the present invention will be described together with comparative examples.

(Example 1)
A stretched orthogonal nonwoven fabric made of PET with a weight per unit area of 20 g / m 2 (Milife (registered trademark), product number TY1010E, manufactured by Nippon Steel Plast Co., Ltd.) was prepared. The fragile air permeability of the stretched orthogonal nonwoven fabric was 200 cm ³ / cm ² · sec. Fibers (2.2 dTex) made of PET were laminated on one side so that the basis weight of the laminated fiber layer was 50 g / m ² and integrated by a needle punch method. Thereby, the stretched orthogonal nonwoven fabric was made into a dense nonwoven fabric, and the reinforcing material which made the fiber layer laminated | stacked on the single side | surface a bulky nonwoven fabric was obtained. The Frazier air permeability of the entire reinforcing material obtained was 170 cm ³ / cm ² · sec.

  After placing this reinforcing material in close contact with the inner surface of the urethane foam mold, the foamed urethane resin is filled into the mold and foamed under heat and pressure to obtain a urethane foam molded product. It was. The reinforcing material was placed with the stretched orthogonal nonwoven fabric in close contact with the inner surface of the mold.

(Example 2)
Reinforcement is performed in the same manner as in Example 1 except that a PET stretched orthogonal nonwoven fabric (Milife (registered trademark), product number TY2020E, manufactured by Nippon Oil Plast Co., Ltd.) having a basis weight of 40 g / m ² is used as the dense nonwoven fabric. A material was prepared, and a urethane foam molded product was obtained using the reinforcing material. The fragile air permeability of the stretched orthogonal nonwoven fabric used in this example was 75 cm ³ / cm ² · sec. Further, the fragile air permeability of the obtained reinforcing material was 67 cm ³ / cm ² · sec.

(Example 3)
On a PET net-like non-woven fabric (Nisseki Warif (registered trademark), product number SSP (T), manufactured by Nippon Oil Plast Co., Ltd.) having a basis weight of 21 g / m ² and a fragile air permeability of 800 cm ³ / cm ² · sec, The stretched orthogonal nonwoven fabric used in Example 1 was superposed, and a fiber (2.2 dTex) made of PET was laminated thereon so that the basis weight of the fiber layer after lamination was 50 g / m ^2, and the needle It was integrated by the punch method. As a result, a reinforcing material having a three-layer structure having a net-like nonwoven fabric as the outermost layer was obtained. The fragile air permeability of the net-like nonwoven fabric was 800 cm ³ / cm ² · sec, and the resulting reinforcing material had a fragile air permeability of 146 cm ³ / cm ² · sec. And the urethane foam molded product was obtained like Example 1 using the reinforcement material.

Example 4
A reinforcing material was produced in the same manner as in Example 1 except that the basis weight of the bulky nonwoven fabric was 40 g / m ² and the lamination integration of the bulky nonwoven fabric and the dense nonwoven fabric was performed by the spunlace method. A foam molded product was obtained. The fragile air permeability of the reinforcing material was 144 cm ³ / cm ² · sec.

(Comparative Example 1)
A reinforcing material was prepared in the same manner as in Example 1 except that a spunbond nonwoven fabric made of PET having a basis weight of 20 g / m ² was used instead of the dense nonwoven fabric, and a urethane foam molded product was obtained using the reinforcing material. It was. The fragile air permeability of the spunbonded nonwoven fabric was 530 cm ³ / cm ² · sec, and the fragile air permeability of the obtained reinforcing material was 396 cm ³ / cm ² · sec.

(Comparative Example 2)
A reinforcing material was produced in the same manner as in Example 3 except that a spunbond nonwoven fabric made of PET having a basis weight of 20 g / m ² was used instead of the dense nonwoven fabric, and a urethane foam molded article was obtained using the reinforcing material. It was. The fragile air permeability of the spunbond nonwoven fabric was 530 cm ³ / cm ² · sec, and the fragile air permeability of the obtained reinforcing material was 330 cm ³ / cm ² · sec.

(Comparative Example 3)
A reinforcing material was produced in the same manner as in Example 4 except that a spunbond nonwoven fabric made of PET having a basis weight of 20 g / m ² was used instead of the dense nonwoven fabric, and a urethane foam molded article was obtained using the reinforcing material. It was. The fragile air permeability of the spunbonded nonwoven fabric was 530 cm ³ / cm ² · sec, and the fragile air permeability of the obtained reinforcing material was 210 cm ³ / cm ² · sec.

  Table 1 shows the evaluation results of the physical properties (weight per unit area, fragile air permeability) of the reinforcing materials of Examples 1 to 4 and Comparative Examples 1 to 3, and the bleeding property of the urethane resin in the urethane foam molded article. The evaluation of the exudation property of the urethane resin is evaluated by visually judging the exudation state of the urethane resin from the reinforcing material of the obtained urethane foam molded product, and a slight exudation is observed when no exudation is observed. The case where it was recognized was indicated by Δ, and the case where clear bleeding was observed was indicated by ×.

実施例１〜４では補強材からのウレタン樹脂の滲み出しは全く見られなかったが、比較例１〜３では多かれ少なかれ、ウレタン樹脂の滲み出しが認められた。比較例３でのウレタン樹脂の滲み出しは僅かであったが、ウレタン発泡成形品の用途によっては、滲み出て硬化したウレタン樹脂が他の部品と擦れあって異音を生じるおそれがある。

In Examples 1 to 4, no seepage of urethane resin from the reinforcing material was observed, but in Comparative Examples 1 to 3, more or less exudation of urethane resin was observed. Although the urethane resin exuded in Comparative Example 3 was slight, depending on the use of the urethane foam molded product, the urethane resin that exuded and hardened may rub against other parts and generate noise.

It is principal part sectional drawing of the urethane foam molded article by one Embodiment of this invention. It is typical sectional drawing of the extending | stretching orthogonal nonwoven fabric shown in FIG. It is sectional drawing of the urethane foam molded product by this invention which provided the reinforcing material so that the whole surface of the urethane foam might be covered. It is sectional drawing of the urethane foam molded product by this invention which provided the reinforcing material of the 3 layer structure. It is a top view of an example of the network structure layer which can be used as the outermost layer shown in FIG. It is a fragmentary sectional view of the uniaxially stretched split fiber film shown in FIG. It is a fragmentary perspective view in the state where the slit was put of the original fabric film used for manufacturing the uniaxial fiber film shown in Drawing 6. FIG. 5 is a partial perspective view of a uniaxially stretched slit film applicable to the network structure layer that is the outermost layer shown in FIG. 4. It is a top view of the nonwoven fabric which is another example of a network structure layer. It is a top view of the woven fabric which is another example of a network structure layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,20 Urethane foam molded article 11,21 Urethane foam 12,22 Reinforcement material 13,23 Bulky nonwoven fabric 14,24 Stretched orthogonal nonwoven fabric 14a, 14b Stretched unidirectionally aligned nonwoven fabric 25 Outermost layer 31 Reticulated layer 41 Uniaxially stretched split fiber film 45 Uniaxially stretched slit film 47 Nonwoven fabric 48 Uniaxially stretched multilayer tape 49 Woven fabric

Claims (3)

It is a reinforcing material that is used for foam molding of urethane resin and is provided integrally with at least part of the surface of the urethane foam molded article,
A bulky nonwoven fabric through which the urethane resin penetrates when the urethane resin is foamed;
In order to suppress the oozing of the urethane resin that has passed through the bulky nonwoven fabric, the basis weight is 10 to 40 g / m ² and the fragile air permeability is 50 to 500 cm ³ / cm ² · sec laminated on one side of the bulky nonwoven fabric. And a dense nonwoven fabric,
A reinforcing material having a fragile air permeability of 10 to 300 cm ³ / cm ² · sec in the entire reinforcing material.   The reinforcing material according to claim 1, wherein an outermost layer made of a nonwoven fabric or a net-like structure is further laminated on a surface of the dense nonwoven fabric opposite to the surface laminated with the bulky nonwoven fabric. The reinforcing material according to claim 1 or 2,
It has a urethane foam formed by foaming a urethane resin,
The reinforcing material is a urethane foam molded product in which the urethane resin penetrates and is integrated with the urethane foam.

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