JP2012188105A - Vehicle undercover and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce ice peeling force and improve chipping resistance while enhancing the road surface side sound absorption performance to improve the noise reduction effect.SOLUTION: An undercover 10 for a vehicle provided so as to cover a lower surface of a vehicle floor includes: core material 11 molded on heating so as to expand along the lower surface of the floor; and nonwoven fabric 13 laminated on the road surface side of the core material 11 and integrally molded with the core material 11. The nonwoven fabric 13 includes melt fibers that fuse at a heating temperature for the core material 11, as constituent fibers.

Description

  The present invention relates to a vehicle undercover that covers a lower surface of a floor of, for example, an automobile and a method for manufacturing the same.

  Conventionally, an automobile may be provided with an under cover that covers the lower surface of the floor. The purpose of providing the under cover is to reduce the air resistance during high-speed driving under the floor, to reduce the noise inside and outside the vehicle, to prevent the ice from peeling off, and to protect the under floor against a collision of pebbles and the like.

  As this type of undercover for a vehicle, for example, as disclosed in Patent Document 1, a plate-like core material formed so as to extend along the lower surface of the floor and a floor side surface of the core material are laminated. The floor-side spunbond nonwoven fabric, the road-side spunbond nonwoven fabric laminated on the road surface side of the core, and the film laminated so as to cover the road-side spunbond nonwoven fabric from the road surface side are integrated. It has been known.

JP 2009-298340 A

  By the way, the reduction in air resistance during high-speed running by the under cover is relatively easy to improve by setting the shape of the under cover because the portion depending on the shape is large.

  However, the effect of reducing noise by the undercover is largely dependent on the laminated structure and material of the undercover. In addition, when the under cover is provided, it may freeze (is icing) with snow or water adhering to the lower surface of the under cover, particularly in winter. If the ice is difficult to peel from the under cover, the ice will gradually grow. Therefore, the under cover is required to have a property that the ice is easy to peel, that is, a low value of the icing peeling force. Further, the surface of the under cover on the road surface side may collide with pebbles or the like that are thrown up by the tire, and in this case, it is required to have a property that is difficult to damage, that is, high chipping resistance.

  For example, like the under cover of Patent Document 1, when a film is laminated on the road surface side, it can be expected that the value of the icing peel strength is low and the chipping resistance is high. It is difficult to adjust the thickness of the film. Specifically, since the film soaks into the core material at the time of molding, if the film is thin, the surface becomes rough, and the value of the icing peel strength becomes high and the chipping resistance becomes low. Conversely, if a thick film is used in consideration of the above-mentioned penetration, good results can be obtained in terms of icing peel strength and chipping resistance, but the film reflects noise such as tire pattern noise, reducing noise. The effect of will not improve so much. For this reason, in the case where a film is provided on the road surface side, good values for icing peel strength and chipping resistance can be obtained, and those which can satisfy noise reduction have not been obtained.

The present invention has been made in view of the above points, and the object of the present invention is to improve the noise reduction effect by increasing the sound absorption performance on the road surface side, and to lower the value of the icing peeling force, The purpose is to increase chipping resistance.

  In order to achieve the above object, in the present invention, a nonwoven fabric containing melt fibers that melt at a temperature at the time of thermoforming the core material is laminated on the road surface side surface of the core material.

  1st invention is a vehicle undercover provided so that the floor lower surface of a vehicle may be covered, It consists of a stampable sheet | seat which contains a thermoplastic resin, a reinforced fiber, and a heat-expandable particle disperse | distributed, and follows the said floor lower surface. A core material formed by heating and a non-woven fabric laminated on the road surface side of the core material and integrally formed with the core material are provided, and the non-woven fabric uses melt fibers that melt at the heating temperature of the core material as constituent fibers. It is characterized by including.

  According to this configuration, the breathable nonwoven fabric is laminated on the road surface side, so that noise such as pattern noise is significantly absorbed. Moreover, since the melt fiber in the nonwoven fabric is melted, the road surface side surface of the nonwoven fabric is smoothed. As a result, even if the road surface side surface of the vehicle undercover is iced, the ice is easily peeled off. Furthermore, since the nonwoven fabric has cushioning properties, when pebbles or the like collide, the impact is absorbed and it is difficult to break.

  A second invention is characterized in that, in the first invention, the nonwoven fabric contains 40 to 100% by weight of the melt fiber, and 0 to 60% by weight of a non-melt fiber that does not melt at the heating temperature of the core material. It is what.

  That is, by making the content of the melt fiber in the above range, the smoothness of the road surface side of the nonwoven fabric is sufficiently obtained by melting the melt fiber at the time of thermoforming the core material, and the ice when icing is more It becomes easier to peel off.

According to a third invention, in the first or second invention, the basis weight of the nonwoven fabric is 100 to 500 g / m ² .

  According to this configuration, the melt fiber melts during heating to improve the smoothness and lower the value of the icing peeling force, and the cushioning property is improved because the nonwoven fabric has a predetermined thickness. In addition, the impact absorbability when pebbles or the like collide further increases.

  According to a fourth aspect of the present invention, in the vehicle undercover according to any one of the first to third aspects, the core includes a first core layer and a second core layer, and the first core layer And the said 2nd core layer is laminated | stacked so that the fiber flow direction of a reinforced fiber at the time of manufacture of these core layers may mutually cross | intersect.

  That is, when manufacturing a member in which reinforcing fibers are mixed, the fibers are mixed so as to extend in the flow direction, and the strength of the member in the longitudinal direction (flow direction during manufacture) and the lateral direction A difference is likely to occur in the strength in the width direction during manufacturing. In the present invention, the member constituting the first core layer and the member constituting the second core layer are laminated so that the flow directions at the time of manufacture intersect with each other. Almost no difference in direction and lateral strength occurs. Thereby, for example, the attachment portion for attaching the under cover to the vehicle is less likely to be damaged.

According to a fifth aspect of the present invention, a stampable sheet containing a thermoplastic resin, reinforcing fibers, and heat-expandable particles dispersed therein is prepared, and a nonwoven fabric is laminated on the stampable sheet, and then heated and compressed with a flat plate type hot press machine. After the nonwoven fabric is pressed against the surface of the bull sheet to produce an adhesive member with the nonwoven fabric attached to the stampable sheet, the hot press machine is opened to expand the heat-expandable particles in the stampable sheet of the heated adhesive member. Then, an inflatable sticking member having a predetermined thickness is formed, and then the inflatable sticking member is put into a cold press machine and press-molded to produce a vehicle undercover.

  That is, after bonding the nonwoven fabric and the core material with a hot press machine, the heat-expandable particles are expanded and foamed at this heating temperature, so that almost all the heat-expandable particles can be effectively expanded and then compressed with a cold press. Therefore, an undercover containing the foamed heat-expandable particles in a high density can be obtained. Various strength performances such as tensile strength and bending strength can be dramatically improved.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing a vehicle undercover according to the fifth aspect of the present invention, wherein the stampable sheet and the nonwoven fabric are heated at 160 to 220 ° C. and have a thickness of 0.7 to 2.5 mm. And is held for 5 to 30 seconds.

  That is, according to the sixth aspect of the invention, the heating temperature and compression time of the hot press machine can be set appropriately, and various performances can be further improved dramatically.

  According to the first invention, since the nonwoven fabric containing the melt fiber that melts at the temperature at the time of heat bonding of the core material is laminated on the road surface side surface of the core material, the sound absorption performance on the road surface side is improved and the noise reduction effect is achieved. In addition to being able to improve, the icing peeling force can be lowered, and the chipping resistance can be increased.

  According to the second invention, since the content of the melt fiber is set to 40 to 100% by weight, the value of the icing peeling force can be further reduced and peeling can be easily performed.

According to the third invention, since the basis weight of the nonwoven fabric is set to 100 to 500 g / m ² , the value of icing peelability can be lowered, and the impact absorbability when pebbles or the like collide can be increased. The chipping resistance can be further improved, and the noise reduction effect can be further improved by improving the sound absorption performance.

  According to the fourth invention, since the first core layer and the second core layer of the core material are laminated so that the flow directions at the time of manufacture intersect each other, the strength of the core material in the vertical direction and the horizontal direction is increased. The difference can be almost eliminated, and breakage of the mounting portion or the like can be suppressed.

  According to the fifth invention, since the heat-expandable particles are expanded and foamed at this heating temperature after bonding the nonwoven fabric and the core material with a hot press machine, almost all the heat-expandable particles can be effectively expanded, Then, since it compresses and shape | molds with a cold press, the undercover in which the expandable heat-expandable particle | grains are contained in high density is obtained. Various strength performances such as tensile strength and bending strength can be dramatically improved.

  According to the sixth aspect of the invention, various performances can be dramatically improved.

It is a fragmentary sectional view of the undercover for vehicles concerning the embodiment of the present invention. It is a figure explaining the manufacturing process of the undercover for vehicles concerning the embodiment of the present invention. It is the figure which showed the expanded cross section of the lamination sheet in each process of FIG. FIGS. 3A, 3B, and 3C are enlarged sectional views of A1, FIG. 2B, A2, and A3 of FIG. 2D, respectively. FIG. 4 is an enlarged view schematically illustrating a distribution state of a thermoplastic resin, a reinforcing fiber, and a heat-expandable particle in the stampable sheet according to the embodiment of the present invention. FIG. 4A shows a state before being heated and compressed by a hot press machine, and FIG. 4B shows a state when being heated and compressed by a hot press machine. FIG. 4 is a diagram schematically showing a cross-section of a core material according to an embodiment of the present invention. FIG. 6 is a diagram corresponding to FIG. It is the table | surface which showed the tensile strength, bending strength, and elastic gradient of Comparative Examples 1 and 2 and Examples 1-3. It is a graph which shows the relationship between the fabric weight of the stampable sheet of Example 2 and Comparative Example 1, and tensile strength. It is a figure which shows schematic structure of the apparatus which tests icing peeling force. It is a table | surface which shows the icing peeling force and chipping resistance of Examples 4-13 and Comparative Examples 3 and 4. FIG. It is a graph which shows the relationship between the fabric weight of a nonwoven fabric, and the sound absorption rate by the case where the fabric weight of the road surface side needle punch nonwoven fabric of Example 1 is changed, and Comparative Example 1. It is a graph which shows the relationship between a melt fiber content and a sound absorption coefficient by the case where the melt fiber content of the road surface side needle punch nonwoven fabric of Example 1 is changed, and the comparative example 1. It is a graph which shows the sound absorption rate at the time of changing an air gap with Example 1 and Comparative Example 1. FIG. It is a figure equivalent to Drawing 3 (b) of this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 is a partial cross-sectional view of a vehicle undercover 10 according to an embodiment of the present invention. The vehicle under cover 10 is provided, for example, so as to cover the lower surface of the floor of an automobile (not shown). Although not shown, the vehicle under cover 10 is provided with a plurality of attachment portions to the vehicle. As the attachment portions, for example, attachment holes including through holes through which bolts, screws or the like that are screwed into the vehicle are inserted. Can be configured. Moreover, as a vehicle to which the vehicle under cover 10 is attached, a passenger car is preferable.

  The vehicle undercover 10 includes a core material 11 that is thermoformed along the lower surface of the floor, a road surface side spunbond nonwoven fabric 12 and a road surface side needle punched nonwoven fabric 13 that are laminated on the road surface side surface (lower surface) of the core material 11. And a floor-side spunbond nonwoven fabric 14 and a floor needle punch nonwoven fabric 15 laminated on the floor-side surface (upper surface) of the core material 11. The road surface side spunbond nonwoven fabric 12 and the road surface side needle punch nonwoven fabric 13 are integrally formed with the core material 11, and the floor side spunbond nonwoven fabric 14 and the floor side needle punch nonwoven fabric 15 are also integrally formed with the core material 11.

  The core material 11 is formed by laminating a first core layer 11a and a second core layer 11b. Each of the first core layer 11a and the second core layer 11b is made of a stampable sheet in which a thermoplastic resin, a reinforcing fiber, and a heat-expandable particle are dispersed, and the heat-expandable particles in the stampable sheet are expanded. It is composed of a joint member. Although the member which comprises the 1st core layer 11a and the member which comprises the 2nd core layer 11b are mentioned later for details, they are laminated | stacked so that the flow direction at the time of manufacture of these members may mutually cross.

  The road surface side spunbond nonwoven fabric 12 is a spunbond method, that is, a melted raw material resin is directly ejected from the tip of a nozzle to obtain continuous long fibers, which are used to form a nonwoven fabric. Although the road surface side spunbond nonwoven fabric 12 will be described in detail later, it is bonded to the second core layer 11b and manufactured as an integral stampable sheet.

The road surface side needle punched nonwoven fabric 13 is made into a nonwoven fabric by repeatedly piercing a needle punching method, that is, a collection of fibers with a needle that moves up and down, and entwining the fibers. The road surface side needle punched nonwoven fabric 13 may include only melt fibers as constituent fibers, or may include melt fibers and non-melt fibers as constituent fibers, and may be configured by mixing these two types of fibers. The road surface side needle punched nonwoven fabric 13 is bonded to the road surface side spunbond nonwoven fabric 12.

  The floor-side spunbonded nonwoven fabric 14 is manufactured as an integral stampable sheet by being bonded to the first core layer 11a, as will be described in detail later. The floor side needle punched nonwoven fabric 15 is formed in the same manner as the road surface side needle punched nonwoven fabric 13. The floor side needle punched nonwoven fabric 15 is bonded to the floor side spunbonded nonwoven fabric 14.

  Next, the manufacturing process of the undercover according to the present invention will be described with reference to FIGS. A web that is an original fabric, a stampable sheet manufactured from the web, a laminated member in which each nonwoven fabric is laminated on the stampable sheet, a laminated member obtained by heating and compressing the laminated member, and a stampable sheet in the laminated member The undercover formed by molding the expanded and bonded member and the expanded bonded member will be described.

  Briefly, the web of the present invention consists of reinforcing fibers, a thermoplastic resin and heat-expandable particles, and is manufactured by a papermaking method. The web is heated, pressurized and cooled to produce a flat and long stampable sheet. This stampable sheet has a structure in which a thermoplastic resin melted and solidified by heating and cooling constitutes a matrix, and reinforcing fibers and heat-expandable particles (unexpanded state) are dispersed therein. In this manufacturing process, the spunbond nonwoven fabric is integrally formed on one surface of the stampable sheet. An apparatus for producing a web into a stampable sheet is conventionally used. The spunbond nonwoven fabric may be integrally formed on at least one surface of the stampable sheet, or the spunbond nonwoven fabric may be a stampable sheet. It may not be formed on either surface. Therefore, in the present invention, the stamper includes the one in which the spunbond nonwoven fabric is integrally formed on at least one surface of the stampable sheet and the one in which the spunbond nonwoven fabric is not integrally formed on one surface of the stampable sheet. Used as a bull seat.

  In an apparatus for manufacturing a web into a stampable sheet, the direction in which the web is introduced into the apparatus and the stampable sheet is taken out is referred to as the flow direction, and the flow direction of the stampable sheet is referred to as the MD direction (Machine Direction). The longitudinal direction of the bull sheet is the MD direction. On the other hand, the width direction of the stampable sheet is the CD direction (Cross Machine Direction). When a material containing fibers is formed into a stampable sheet, the extending direction of the majority of fibers is the MD direction, and the tensile strength in the MD direction is higher than the tensile strength in the CD direction.

  The manufacturing method of the under cover of this embodiment is demonstrated in detail based on FIG.2 and FIG.3. In the present embodiment, both the MD direction of the stampable sheet 1 constituting the first core layer 11a of the core material 11 and the MD direction of the stampable sheet 1 constituting the second core layer 11b are substantially orthogonal to each other. Stack the stampable sheets 1 and 1 together. In this embodiment, as shown in FIGS. 2 (a) and 3 (a), the stampable sheets 1 and 1 have spunbond nonwoven fabrics 1b and 1b on one surface of the stampable sheet portions 1a and 1a, respectively. It is integrally formed. And the stampable sheet | seat parts 1a and 1a are put together and piled up by making the surface side which has the spunbond nonwoven fabric 1b outside, and the laminated member 2a with which the two stampable sheets 1 and 1 were piled up is manufactured. Further, the needle punched nonwoven fabric 1c is overlapped on both outer sides of the laminated member 2a to produce the laminated member 2b as shown in FIGS. 2 (b) and 3 (b). As shown in FIG. 2 (c), the laminated member 2 b stacked in this way is heated and compressed by a hot press machine 20 to form a flat plate-like bonding member 2 c that is bonded to each other.

  Specifically, the hot press machine 20 includes a lower die 21, an upper die 22, and an upper die driving device 23. The surfaces of the lower mold 21 and the upper mold 22 are substantially flat. In addition, these surfaces are heated. The upper mold driving device 23 is configured to drive the upper mold 22 up and down and drive it in a direction in which the upper mold 22 contacts and separates from the lower mold 21. The laminated member 2b is placed on the surface of the lower die 21, and the upper die 22 is lowered by the upper die driving device 23 to press and heat the laminated member 2b in the thickness direction. Thereby, the road surface side needle punched nonwoven fabric 1c is firmly bonded to the road surface side spunbonded nonwoven fabric 1b, and the floor side needle punched nonwoven fabric 1c is firmly bonded to the floor side spunbonded nonwoven fabric 1b. Is done. At this time, the melt fibers of the road surface side needle punched nonwoven fabric 1c and the floor side needle punched nonwoven fabric 1c are melted, and the non-melt fibers remain unmelted to form layers of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 15. Is done.

  Then, as shown in FIG.2 (d), the upper mold | type 22 is raised with the upper mold | type drive device 23, and the compression state of the bonding member 2c is open | released. Thereby, the expandable bonding member begins to expand and expand at the heating temperature when the heat-expandable particles 53 in the bonding member 2c are heated by the hot press machine 20, as shown in FIG. 2d is formed. At this time, the stampable sheet portions 1a and 1a are formed as the core materials 11a and 11b.

  The thermoplastic resin, the reinforcing fibers, and the heat-expandable particles when the stampable sheet 1 and the nonwoven fabrics 12, 13, 14, and 15 are stacked and heated and compressed by the hot press machine 20 are schematically shown in FIG. explain. FIG. 4A schematically shows a dispersion state of the reinforcing fibers 51, the thermoplastic resin 52, and the heat-expandable particles 53 when the stampable sheet 1 is manufactured. 51 indicates a rod-like reinforcing fiber, 52 indicates a thermoplastic resin that bonds the reinforcing fibers 51 to each other, and 53 indicates spherical heat-expandable particles (unexpanded state) dispersed between the reinforcing fibers 51. . FIG. 4B schematically shows a dispersion state of the reinforcing fibers 51, the thermoplastic resin 52, and the heat-expandable particles 53 when heated and compressed by the hot press machine 20. The reinforcing fibers 51 and the heat-expandable particles (unexpanded state) 53 are hardly changed, but the thermoplastic resin 52 is crushed and the surface area is enlarged. Thereby, the area where the reinforcing fibers 51 are bonded to each other with the thermoplastic resin 52 is increased, and the adhesive strength is increased. That is, it is heated and compressed by the hot press machine 20 to crush the thermoplastic resin 52 in the stampable sheet 1 to increase the surface area and increase the bonding force between the reinforcing fibers 51, and the nonwoven fabrics 12, 13, After the 14, 15 and the stampable sheet 1 are brought into strong contact, the stampable sheet 1 is heated at this heating temperature to expand the heat-expandable particles 53 in the stampable sheet 1. In this manner, the hot press machine 20 heats and compresses the stampable sheet 1 and the nonwoven fabrics 12, 13, 14, and 15 to crush the thermoplastic resin 52 in the stampable sheet and increase the surface area. As a result, the non-woven fabrics 12, 13, 14, 15 and the stampable sheet 1 can be strongly brought into close contact with each other while increasing the bonding force between the reinforcing fibers 51. In particular, since the entire stampable sheet 1 can be heated by the hot press machine 20, even when the hot press machine 20 is opened, the entire stampable sheet 1 is heated almost uniformly in a short time, and the heat-expandable particles 53 can be uniformly expanded and dispersed.

  Next, the foamed state of the heat-expandable particles 53 will be schematically described with reference to FIG. FIG. 5A shows the stampable sheet 1 in which the heat-expandable particles 53 are in an unfoamed state. The white triangles in the figure indicate the thermoplastic resin 52, and the lines indicate the reinforcing fibers 51. The white open circles indicate the heat-expandable particles 53 (unfoamed). When the stampable sheet 1 is heated by the heating press device 20 and then the heating press device 20 is opened, as shown in FIG. 5B, the heat-expandable particles 53 are foamed and large bubbles 53 (FIG. 5B). ) Is indicated by a white circle in the middle. As will be described later, when this is formed by the forming apparatus 30, the bubbles 53 become dense as shown in FIG.

  Next, after heating and compressing with the hot press machine 20, the hot press machine 20 is opened and the heat-expandable particles 53 are foamed, and then, as shown in FIG. The combined member 2d is formed into an undercover shape. Specifically, the molding apparatus 30 includes a lower mold 31, an upper mold 32, and an upper mold driving device 33. The upper mold driving device 33 is configured to drive the upper mold 32 in the vertical direction so as to drive in a direction in which the upper mold 32 contacts and separates from the lower mold 31. The undercover 10 is obtained by placing the expansion bonding member 2d on the lower mold 31 of the molding device 30, lowering the upper mold 32 by the upper mold driving device 33, and cold pressing the bonding member 2d in the thickness direction. (See FIG. 1). In particular, in the previous step, most of the heat-expandable particles 53 are greatly expanded, and when formed by the forming apparatus 30, the bubbles of the heat-expandable particles 53 are not crushed as shown in FIG. It has become denser and stronger.

  Next, the web of the present invention, the stampable sheet, the reinforcing fiber in the stampable sheet, the thermoplastic resin and the heat-expandable particle, the melt fiber and the non-melt fiber in the nonwoven fabric will be described.

  As the reinforcing fiber used in the present invention, either an inorganic fiber or an organic fiber may be used, and a fiber obtained by combining or mixing these may be used. Usable fibers include, for example, glass fibers, carbon fibers, boron fibers, stainless steel fibers and other metal fibers and mineral fibers as inorganic fibers, and aramid fibers, polyester fibers, polyamide fibers as organic fibers. And natural fibers such as hemp. Moreover, you may use combining these 1 type (s) or 2 or more types. In addition, from the viewpoint of imparting a high reinforcing effect to the undercover, inorganic fibers are preferable to organic fibers. Among them, carbon fibers are preferably used when emphasizing strength. On the other hand, from the viewpoint of cost, it is preferable to use glass fiber, and from the viewpoint of thermal recycling that no residue remains even if incinerated, organic fiber is preferable.

  The average diameter of the reinforcing fiber is preferably 3 to 50 μm from the viewpoint of sufficiently securing the reinforcing effect and the expandability of the stampable sheet. More preferably, it is φ3 to 30 μm. By using the reinforcing fibers having an average diameter in the above range, the yield of the heat-expandable particles during papermaking can be improved. In addition, when expecting an increase in the expansion amount due to the synergistic effect of the spring back of the reinforcing fiber and the expandability of the heat-expandable particles, the average plays a role of filling the space between the reinforcing fiber having an average diameter of φ100 to 1000 μm. A mixture of reinforcing fibers having a diameter of 3 to 50 μm may be used. Moreover, it is preferable that the average length of a reinforced fiber is a thing of the range of 3-100 mm from a viewpoint of ensuring a sufficient reinforcement effect, expansibility, and a moldability. In addition, from the viewpoint of more uniformly dispersing the thermoplastic resin and the reinforcing fiber in the previous stage of the paper making process, the average length of the reinforcing fiber is more preferably in the range of 3 to 50 mm. The average diameter and average length are values obtained by measuring about 50 diameters and lengths of reinforcing fibers or webs, stampable sheets, and undercover reinforcing fibers before use using a microscope or the like. Is the average. The reinforcing fiber may be observed using a microscope or the like after firing the web, stampable sheet, and under cover at a temperature of about 600 ° C.

  The reinforcing fiber used in the present invention is preferably subjected to surface treatment with a coupling agent or a sizing agent. In particular, in order to improve the wettability and adhesiveness between the reinforcing fiber and the thermoplastic resin, it is preferable to perform a treatment with a silane coupling agent. As the silane coupling agent, a vinyl silane, amino silane, epoxy silane, methacryl silane, chloro silane, mercapto silane, or the like can be used. The surface treatment of the reinforcing fiber with the silane coupling agent can be performed by a known method such as a method of spraying the silane coupling agent solution while stirring the reinforcing fiber or a method of immersing the reinforcing fiber in the coupling agent solution. it can. In addition, it is preferable that the processing amount of the said silane coupling agent is 0.001-0.3 mass% with respect to the mass of the reinforced fiber to process. If it is less than 0.001 mass%, the effect of the silane coupling agent is small, and sufficient adhesive strength between the reinforcing fiber and the thermoplastic resin cannot be obtained. On the other hand, if it exceeds 0.3 mass%, the effect of the silane coupling agent is saturated. Because it does. More preferably, it is the range of 0.005-0.2 mass%.

  The reinforcing fiber used in the present invention is desirably fibrillated into a single fiber in order to increase the strength and expansibility of the stampable sheet. For this purpose, the reinforcing fiber is dispersed with a water-soluble sizing agent. It is preferable to process. As the sizing agent, a polyethylene oxide-based or polyvinyl alcohol-based water-soluble resin can be used. The treatment amount of the sizing agent is 2 mass% or less, preferably 1 mass% or less with respect to the mass of the reinforcing fiber to be treated. This is because if it exceeds 2 mass%, it becomes difficult to disentangle the fibers in the papermaking process. In addition, the minimum of processing amount is about 0.05 mass%. If the amount of processing is too small, the handling properties will deteriorate.

  Next, the thermoplastic resin used in the present invention will be described.

  Examples of the thermoplastic resin used in the present invention include polyolefin resins such as polyethylene and polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polyamide, polyacetal, or ethylene-vinyl chloride copolymer, ethylene-vinyl acetate. A copolymer, a styrene-butadiene-acrylonitrile copolymer, a thermoplastic elastomer such as EPM, EPDM, or the like can be used alone or in combination. Among these, polyolefin resins such as polyethylene and polypropylene are preferable because they are excellent in strength, rigidity, and moldability. In particular, polypropylene is more preferable because it has an excellent balance of these properties and is inexpensive. Further, among polypropylenes, those having an MFR (melt flow rate, however, 230 ° C., 21.17 N) measured under the conditions defined in JIS K 6921-2: 1997 are in the range of 1 to 200 g / 10 min. The thing of the range of 10-150 g / 10min is more preferable.

  Furthermore, in order to improve the adhesion between the thermoplastic resin and the reinforcing fiber, the thermoplastic resin is modified with various compounds such as acids such as unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides and epoxy compounds. It can be used in combination with an unmodified thermoplastic resin. The modification treatment can be performed, for example, by graft copolymerizing polypropylene with maleic acid, maleic anhydride, acrylic acid, or the like. As the modified product, one having a modified group such as an acid anhydride group or a carboxyl group in the molecule is particularly preferable from the viewpoint of improving the strength.

  The thermoplastic resin may be in the form of particles such as powder, pellets, flakes, or fibers. From the viewpoint of improving the handling property of the web and the yield of the heat-expandable particles, and from the viewpoint of sufficiently entangled the molten thermoplastic resin and the reinforcing fiber when producing the stampable sheet, It is preferable to use a fibrous material together with a particulate material. Here, when using a particulate thing, it is preferable to use an average particle diameter of (phi) 100-2000 micrometers, and the viewpoint of uniformly disperse | distributing in a stampable sheet has more preferable (phi) 100-1000 micrometers. On the other hand, when using a fibrous thing together, it is preferable to use an average diameter of φ1 to 50 μm and an average length of 1 to 50 mm. From the viewpoint of uniform dispersion in the foam liquid, the average length is The thing of 1-30 mm is more preferable.

  Next, the heat-expandable particles used in the present invention will be described.

The heat-expandable particles used in the present invention have a characteristic that when heated above a certain temperature, the softened shell expands due to the vaporizing and expanding pressure of the core. The present invention has a great feature in that the heat-expandable particles are used as a material constituting the web, the stampable sheet, and the expansion bonding member thereof. By using these heat-expandable particles, a larger expansion amount can be ensured than in the case of the springback action of the reinforcing fiber alone, so that the density can be further reduced, and a lightweight and rigid expansion bonded member is obtained. be able to.

  In the present invention, known particles can be used as the heat-expandable particles. Particularly, the core-shell type heat-expandable particles in which the core is a liquid hydrocarbon and is encapsulated by a shell made of a thermoplastic resin having gas barrier properties. Is preferred. Usually, hydrocarbons used in the core have a boiling point lower than the softening point of the thermoplastic resin of the shell. For example, hydrocarbons and ethers having a boiling point of 150 ° C. or less such as isobutane, pentane, and hexane are used. Can be mentioned. Examples of the thermoplastic resin that forms the shell include polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polystyrene, polyvinyl chloride, polyvinylidene chloride, methacrylic resin, ABS resin, and ethylene-vinyl acetate. Known thermoplastic resins such as copolymers, polyamide resins, polyethylene terephthalate, polybutylene terephthalate, polyurethane, polyacetal, polyphenylene sulfide, and fluororesin can be exemplified. Particularly preferred is a heat-expandable particle having a core made of a liquid hydrocarbon such as isobutane, pentane or hexane and a shell made of a thermoplastic resin such as acrylonitrile copolymer or polyvinylidene chloride.

  The average diameter of the heat-expandable particles is preferably φ5 to 200 μm before heat expansion, more preferably φ10 μm or more and less than φ100 μm, and still more preferably φ20 μm or more and φ100 μm or less. When the particle diameter before expansion is less than φ5 μm, it passes through the gaps between the reinforcing fibers at the time of papermaking and easily drops off, resulting in a decrease in yield. On the other hand, if it exceeds φ200 μm, the size of the heat-expandable particles after expansion is too large, the thickness of the expansion molded product becomes non-uniform, or the surface quality is deteriorated. The heat-expandable particles preferably have an average diameter of φ10 to 2000 μm when expanded, and more preferably φ20 to 1000 μm. If the average diameter of the heat-expandable particles after expansion is too small, the amount (number) of heat-expandable particles necessary for expanding the stampable sheet becomes large. On the other hand, if the average diameter after expansion is too large, irregularities are generated on the surface of the expansion molded product, which deteriorates the surface properties. The average diameter of the heat-expandable particles after expansion is a value obtained by observing about 50 heat-expandable particles in the expansion-molded product with an optical microscope or the like and averaging the measured diameters.

As described above, when the heat-expandable particles are heated above a certain temperature, the softened shell starts to expand due to the pressure at which the core vaporizes and expands. In the present invention, this temperature is referred to as an expansion start temperature, and is defined as a temperature at which the particle diameter of the heat-expandable particles starts to increase rapidly when the heat-expandable particles are heated at 10 ° C./min. The heat-expandable particles used in the present invention preferably have an expansion start temperature of 120 ° C. or higher, more preferably 130 to 230 ° C. When the expansion start temperature is less than 120 ° C., the heat-expandable particles themselves are inferior in heat resistance, and it is necessary to extremely lower the drying temperature of the paper-made web. On the other hand, when the expansion start temperature exceeds 230 ° C., the heating temperature for expansion becomes too high, which may cause deterioration of the thermoplastic resin.

  The expansion start temperature of the heat-expandable particles preferably has a smaller difference from the melting point of the thermoplastic resin constituting the matrix. If the expansion start temperature of the heat-expandable particles is too lower than the melting point of the thermoplastic resin, the thermoplastic resin will melt and flow around the reinforcing fibers, and the heat-expandable particles will expand too much before adhering. It is not preferable. On the other hand, if the expansion start temperature is too high, it is necessary to heat to a high temperature in order to obtain a sufficient expansion thickness, which may deteriorate the thermoplastic resin. Therefore, the difference between the expansion start temperature of the heat-expandable particles and the melting point of the thermoplastic resin constituting the matrix is preferably within ± 30 ° C.

Further, the heat-expandable particles preferably have a maximum expansion temperature higher than the melting point of the thermoplastic resin, and the temperature difference is more preferably within 50 ° C. Here, the maximum expansion temperature is a temperature at which the particle diameter of the heat-expandable particles becomes maximum when the heat-expandable particles are heated at 10 ° C./min. This is because if the maximum expansion temperature is too higher than the melting point of the thermoplastic resin, it is necessary to heat to a high temperature in order to obtain sufficient expansion property, which may deteriorate the thermoplastic resin.

  Next, the basis weight of the web of the present invention and the blending ratio of the reinforcing fiber, the thermoplastic resin and the heat-expandable particles constituting the web, stampable sheet, and undercover will be described.

First, the basis weight of the web or the like of the present invention is preferably in the range of 100 to 2000 g / m ² . If the basis weight of the web is less than 100 g / m ² , when the under cover is used, sufficient thickness cannot be obtained and the rigidity is reduced. On the other hand, if it exceeds 2000 g / m ² , the weight of the expansion molded product is reduced. This is because it becomes difficult. A more preferred basis weight is in the range of 500 to 1000 g / m ² .

  Next, the blending ratio of the reinforcing fiber and the thermoplastic resin constituting the web of the present invention varies depending on the specific gravity of the reinforcing fiber and the thermoplastic resin used and the content of other additives and colorants, but the bending strength In order to obtain an undercover having high mechanical strength such as (buckling strength) and flexural modulus (elastic gradient), the reinforcing fiber / thermoplastic resin should be in the range of 3/97 to 60/40 by mass ratio. Is preferred.

  Moreover, it is preferable that content of the heat | fever expansible particle which comprises the web of this invention is 1-40 mass parts with respect to a total of 100 mass parts of a reinforced fiber and a thermoplastic resin. If the amount is less than 1 part by mass, the effect of improving the expansibility does not appear. On the other hand, if the amount exceeds 40 parts by weight, the effect of improving the expansibility becomes too large, and not only the interior member but also the surface layer is reduced in density. Stiffness and buckling resistance are reduced.

  The web of the present invention includes additives such as an antioxidant, a light stabilizer, a metal deactivator, a flame retardant, and carbon black in addition to the above-described thermoplastic resin, reinforcing fiber, and heat-expandable particles. Colorants, organic binders, and the like can be included as required. Further, the above additives and colorants may be contained by, for example, pre-coating on reinforcing fibers or thermoplastic resin, blending at the time of mixing, or spraying and adding to the web. .

  The needle punched nonwoven fabric (melt fiber and non-melt fiber) of the present invention will be described. The melt fiber of the road surface side needle punched nonwoven fabric 13 is a fiber having a melting point lower than the temperature when the core material 11 is heated by the hot press machine 20 and melts when heated and compressed by the hot press machine 20, and is a polypropylene resin. Polyolefin resins such as low melting point PET (polyethylene terephthalate) and polyethylene resin are preferable. In particular, the low melting point PET resin having a melting point of 100 to 230 ° C. tends to maintain the low fluidity as a whole even when the surface melts when heated by a hot press machine, and it is difficult to cover the entire surface. Therefore, it is preferable that the air permeability is ensured, and it is particularly preferably 110 ° C. or higher and the heating temperature or lower with a hot press. This melt fiber not only exhibits an adhesive function by melting at the time of heating, but also has a film shape, and has an effect of lowering the value of icing peeling force and increasing chipping resistance. In particular, this melt fiber does not attach another film, but functions as a film inside the non-woven fabric, and there is no need for a bonding process or adhesive, and a porous film is formed on it. Therefore, it is excellent in noise prevention functions such as sound absorption. It is preferable from the viewpoint of required performance that the melt fiber has an average diameter of 4 to 7 dtex and an average length of 30 to 70 mm.

  In this embodiment, the needle punched nonwoven fabric is used. However, the present invention is not limited to this, and a spun pond nonwoven fabric or a nonwoven fabric obtained by another fleece bonding method may be used. In particular, when a needle punched nonwoven fabric is used, the moldability (elongation) is good and the blending amount of the melt fiber is easy to adjust.

  The non-melt fiber is a fiber having a melting point higher than the temperature at which the core material 11 is thermoformed and does not melt when the core material 11 is thermoformed. For example, a general PET resin fiber having a melting point of about 240 to 260 ° C. It is preferable that In particular, the same fiber as the melt fiber is preferable from the viewpoint of compatibility.

In the present invention, if the basis weight of the road surface side needle punched nonwoven fabric 13 is too small, the value of the icing peeling force becomes high and the icing ice becomes difficult to peel off, and the chipping resistance is reduced and the performance is poor. Become. On the other hand, if the amount is too large, the soundproofing performance such as sound absorption is deteriorated. Therefore, the basis weight is preferably set to 100 to 500 g / m ^2, it is particularly preferable to a 150 to 250 g / m ^2.

  If the content of the melt fiber of the road surface side needle punched nonwoven fabric 13 is too small, a coating film due to the melt will not be sufficiently formed, the feel of the nonwoven fabric will remain, and the value of the icing peel force will be high, making it difficult to peel off. The melt fiber content may be 100% by weight from the viewpoint of icing peelability and chipping resistance. However, when only melt fiber is used, the entire nonwoven fabric tends to melt, and the nonwoven fabric has cushioning properties. It tends to get worse. In that case, it is possible to cope by increasing the basis weight of the nonwoven fabric or adjusting the heating temperature and heating time to reduce the overall melt, but add non-melt fiber to the melt fiber. It is possible to respond. The blending ratio of the melt fiber and the non-melt fiber is preferably 40 to 100% by weight, particularly 60 to 80% by weight. That is, the non-melt fiber is preferably 0 to 60% by weight, particularly preferably 20 to 40% by weight.

  The floor side spunbond nonwoven fabric 14 and the floor side needle punched nonwoven fabric 15 are the same as the road surface side spunbond nonwoven fabric 12 and the road surface side needle punched nonwoven fabric 13.

  In addition, the floor side needle punched nonwoven fabric can prevent the thermoplastic resin of the core from oozing out when it is heated with a hot press machine and adhere to the mold, resulting in poor release properties. What is necessary is just what is excellent in adhesiveness with a core material, It is not restricted to the thing of the said embodiment, Nonwoven fabrics other than a needle punch nonwoven fabric may be sufficient. However, using the same material is advantageous in terms of cost.

In this embodiment, the spunbonded nonwoven fabric is provided integrally with the core material in the manufacturing process of the stampable sheet, and can be omitted from the viewpoint of the performance targeted by the present invention. It is effective in terms of cost. In addition, when providing a spunbonded nonwoven fabric, 12-100 g / m < ² > is the practical range of the fabric weight.

  Next, a method for producing the web, stampable sheet, and undercover according to the present invention will be described.

  The method for producing a web according to the present invention is produced by producing a foam liquid in which reinforcing fibers, a thermoplastic resin, and heat-expandable particles are dispersed in a surfactant-containing aqueous medium containing microbubbles as a dispersion liquid. . You may disperse | distribute and mix the said raw material not in foaming liquid but in the water which does not contain a thickener or a flocculant. Note that the use of foam liquid retains the reinforcing fibers, thermoplastic resin, and heat-expandable particles on the surface of the foam and disperses them uniformly in the foam liquid, so that separation does not occur during the transportation of the dispersion liquid. Have. In the production of the web in the present invention, a dispersion liquid (foam liquid) containing reinforcing fibers, a thermoplastic resin, and heat-expandable particles is poured onto a porous support such as a papermaking screen and sucked from below the porous support. And then defoaming and depositing the solid content in the dispersion on the porous support.

  Any of anionic, nonionic, and cationic surfactants may be used as the surfactant used in the foam making method. Particularly, sodium dodecyl benzene sulfonate, palm oil fatty acid diethanolamide, and the like are excellent in terms of the effect of uniformly dispersing the raw materials mainly composed of reinforcing fibers and thermoplastic resin in the medium. Can be used.

  The web obtained by foaming is dried under conditions (temperature and time) in which the heat-expandable particles do not expand at the maximum. That is, if the heat-expandable particles in the web are maximally expanded in the drying stage, not only the handling property of the web is lowered, but also the heat-expandable particles are crushed during compression when manufacturing a stampable sheet. For this reason, the expandability of the stampable sheet when manufacturing the interior member is sometimes insufficient.

  A certain amount of heat is required for maximum expansion of the heat-expandable particles. Therefore, in order to prevent the heat-expandable particles from expanding to the maximum, it is necessary to control the heating temperature and time so that the amount of heat input during drying is less than the certain amount of heat. Specifically, the heating temperature for drying is set to 30 ° C. or less from the maximum expansion temperature, and the heating time is {2 × (maximum expansion temperature−expansion start temperature)} when the heating temperature is the maximum expansion temperature or less. When the heating temperature is higher than the maximum expansion temperature, it should be within {300 / (heating temperature−maximum expansion temperature)} minutes and within {2 × (maximum expansion temperature−expansion start temperature)} minutes. preferable.

  In addition, when the web obtained by foaming was coated with an emulsion or aqueous solution containing an organic binder by spray spraying or a roll coater and impregnated by vacuum suction or the like from the opposite side, the web was dried. Occasionally, reinforcing fibers, thermoplastic resins, and heat-expandable particles adhere efficiently, which not only improves yield, but also improves handling and production efficiency, which is preferable.

  Next, the manufacturing method of the flat stampable sheet of this invention is demonstrated.

  The stampable sheet of the present invention heats and presses the web obtained by foaming under the conditions (temperature and time) above the softening point or melting point of the thermoplastic resin and under which the heat-expandable particles do not undergo maximum expansion. Then, by cooling and solidifying, the thermoplastic resin is melted to form a matrix, and the dispersed reinforcing fibers and the heat-expandable particles are sufficiently bonded and bonded by the melted and solidified thermoplastic resin. To do. Here, the conditions (temperature and time) at which the maximum expansion is not performed are the same as those described above. The reason why the melting point of the thermoplastic resin is equal to or higher than the melting point is that if the melting point is lower than the melting point, the thermoplastic resin is not sufficiently fused to the reinforcing fibers and the heat-expandable particles, and the necessary strength cannot be obtained. The reason why the particles are heated under the condition that the maximum expansion is not achieved is that if the heat-expandable particles are expanded at the maximum in this heating process, not only the handling property of the stampable sheet is lowered but also the compression during the production of the stampable sheet is performed. This is because the heat-expandable particles are crushed and the expandability necessary for the subsequent production of the expansion-molded product may not be obtained.

  It is preferable to compress the stampable sheet so that the specific gravity of the stampable sheet is 0.3 or more as a pressurizing condition when the stampable sheet is manufactured by heating the web and melting the thermoplastic resin and then pressurizing. If it is less than 0.3, the flowability of the thermoplastic resin is insufficient, and a structure in which reinforcing fibers and heat-expandable particles are dispersed in the thermoplastic resin as a matrix cannot be formed. More preferably, the specific gravity is 0.4 or more. However, if compressed too much, the reinforcing fibers may be broken or the sheet weight may be reduced (the sheet area increases and the thickness decreases). preferable.

  In the stampable sheet manufacturing method of the present invention, the web may be pressed after the thermoplastic resin is melted, or may be heated and pressed simultaneously. The pressurizing method includes a batch type intermittent press method, a continuous press method using a Teflon (registered trademark) or steel belt, a roll press method, and the like, and any method may be used. In order to improve the handleability of the stampable sheet, it may be pressurized while the thermoplastic resin is melted, then unloaded and expanded, and cooled in a thicker state than when pressurized. Furthermore, the method of simultaneously drying and heating the web, followed by pressurization is efficient in production and economical.

  In this manufacturing method, the heating and compression conditions of the hot press machine will be described.

  The heating temperature condition is that the thermoplastic resin in the stampable sheet must be heated to the softening temperature or melting point of the thermoplastic resin and the expansion start temperature of the heat-expandable particles to soften or melt the thermoplastic resin. If it is too low, the thermoplastic resin in the stampable sheet will be insufficiently softened or melted, and the bonding strength between the stampable sheet and the nonwoven fabric will be insufficient. Further, the stampable sheet is not sufficiently heated, and the heat-expandable particles are not expanded as expected. On the other hand, when the heating temperature is too high, the thermoplastic resin in the stampable sheet is excessively melted, the movement from the reinforcing fibers becomes large, and the bonding force between the reinforcing fibers becomes insufficient. Moreover, the possibility of impairing the smoothness of the surface of the nonwoven fabric increases, which is not preferable.

  On the other hand, if the heating temperature is too high, the stampable sheet is overheated and the heat-expandable particles are damaged. Therefore, it is preferable that the heating temperature of a hot press machine shall be 160-220 degreeC.

  As for the compression condition of the laminated member in the hot press machine, if the laminated member is compressed too much, the heat-expandable particles are crushed too much, and the expansibility necessary for the subsequent production of the inflatable bonded member cannot be obtained. In addition, the thermoplastic resin that bonds the reinforcing fibers in the stampable sheet may move too much and the adhesive strength with the reinforcing fibers may be insufficient. On the other hand, if the compression of the laminated member is insufficient, the surface area cannot be expanded by crushing the thermoplastic resin, and the contact area with the reinforcing fibers cannot be increased. As a result, the adhesive strength between the reinforcing fiber and the thermoplastic resin cannot be sufficiently secured, and the rigidity is insufficient.

  Therefore, the control of the stampable sheet at the time of compression can be obtained from the compression ratio before and after compression, the specific gravity, and the like. However, in actual hot press machine work management, it is easy to determine and manage the hot press machine interval rather than specific gravity and compression ratio, and such management is often performed. Therefore, in the under cover, the interval of the hot press machine at the time of compression is set to 0.7 to 2.5 mm, particularly 1.0 to 1.7 mm. It is easy to manage the actual numerical values based on the material and the respective thicknesses, and by finding an appropriate thickness empirically within the above range and controlling the thickness during pressing.

  The compression time varies slightly depending on the composition and thickness of the stampable sheet and the nonwoven fabric material. However, if the time is too long, the molten thermoplastic resin in the stampable sheet oozes out and appears on the nonwoven fabric surface. On the contrary, if the time is too short, the thermoplastic resin is insufficiently softened or melted, resulting in poor adhesion. Therefore, the compression time is preferably 5 to 30 seconds, particularly 7 to 20 seconds.

  Next, the case where the said vehicle under cover 10 is used is demonstrated. Since the road surface side needle punched nonwoven fabric 13 is laminated on the road surface side surface of the vehicle undercover 10, noise such as tire pattern noise passes through the needle punched nonwoven fabric 13 and is absorbed by the core material 11.

  Moreover, since the melt fiber in the road surface side needle punched nonwoven fabric 13 is melted, the surface on the road surface side of the needle punched nonwoven fabric 13 is smoothed. Thereby, when water adheres to the road side surface of the needle punched nonwoven fabric 13, the water is less likely to permeate, and even if the water freezes, the needle punched nonwoven fabric 13 is less likely to get entangled with the fibers. Therefore, when the road surface side surface of the vehicle under cover 10 is iced, the ice is easily peeled off.

  Furthermore, since the road surface side needle punched nonwoven fabric 13 has a cushioning property, when the pebbles and the like which the tire bounces up collide with the under cover 10, the impact is absorbed by the road surface side needle punched nonwoven fabric 13. Thereby, the undercover 10 is hardly damaged.

  As described above, according to this embodiment, the road surface side needle punched nonwoven fabric 13 containing melt fibers that melt at the temperature at the time of heat forming the core material 11 is formed on the road surface side surface of the core material 11 of the undercover 10. Since they are laminated, the sound absorption performance on the road surface side can be enhanced to improve the noise reduction effect, the icing peeling force can be lowered, and the chipping resistance can be enhanced.

  In addition, in the said embodiment, although the floor side spunbond nonwoven fabric 14 is provided in the floor side of the core material 11, and the road surface side spunbond nonwoven fabrics 14 and 12 are provided in the road surface side, one or both of these spunbond nonwoven fabrics 152 are abbreviate | omitted. May be. Moreover, although the floor side needle punch nonwoven fabric 15 is provided in the floor side of the core material 11, you may abbreviate | omit.

(Example)
Embodiment 1 of the present invention will be described below.

Stampable sheet (first core layer 11a and second core layer 11b)
Thermoplastic resin: polypropylene particles (weight average molecular weight 200,000, MFR 65 g / 10 min, average particle diameter φ500 μm, melting point 165 ° C.)
Reinforcing fiber: Glass fiber (length 25 mm, average diameter 13 μm)
Heat-expandable particles: core hydrocarbon
Shell part Acrylic nitrile copolymer
Average particle diameter φ70μm
Expansion start temperature 155 ° C
Maximum expansion temperature 176 ° C
Weight per unit area: 400 g / m ² each

  Both stampable sheets are overlapped so that the MD direction of the stampable sheet constituting the first core layer 11a and the MD direction of the stampable sheet constituting the second core layer 11b are substantially orthogonal. Moreover, the plate | board thickness of the undercover 10 after a shaping | molding with a cold press machine is 7 mm. In addition, the mixing amount of the heat-expandable particles was set so that the plate thickness would be about 20 mm when foamed in a free state without press molding.

Nonwoven fabric (road surface side needle punched nonwoven fabric 13 and floor side needle punched nonwoven fabric 15)
Weight per unit area: 200 g / m ²
Melt fiber: PET fiber having a melting point of 130 ° C. (average fiber length: 30 to 70 mm,
Average fiber diameter: 4-7 dtex), 70% by weight
Non-melt fiber: PET fiber having a melting point of 250 ° C. (average fiber length: 30 to 70 mm,
Average fiber diameter: 4-7 dtex), 30% by weight
Road surface side spunbond nonwoven fabric 13 and floor side spunbond nonwoven fabric 15
Weight per unit area: 15 g / m ²
Conditions of hot press machine Interval between upper die and lower die during compression: 1.5mm
Heating temperature: 190 ° C
Compression time: 15 seconds Cold press machine Compression time: 30 seconds

  As is generally known under the above conditions, a stampable sheet is prepared in which a spunbonded nonwoven fabric is integrally provided on one surface. The stampable sheet is laminated with the surface side on which the spunbond nonwoven fabric is integrally provided facing outside, and the needle punched nonwoven fabric is laminated on both outer sides of the stampable nonwoven fabric to produce a laminated member. The laminated member was heated and compressed with a hot press machine under the above conditions, and then the hot press machine was opened to expand and foam the heat-expandable particles, and then formed into an undercover shape with a cold press machine.

(Example 2)
Embodiment 2 of the present invention will be described below.

  The difference between Example 2 and Example 1 is that the MD direction of the stampable sheet constituting the first core layer 11a matches the MD direction of the stampable sheet constituting the second core layer 11b. The other points are the same as those of the first embodiment except that both stampable sheets are overlapped.

(Example 3)
Embodiment 3 of the present invention will be described below.

Example 3 differs from Example 1 in that the core material 11 has a one-layer structure, and the basis weight of the stampable sheet constituting the core material 11 is 800 g / m ^2. The others are the same as in the first embodiment.

Example 4
The core material 11 of the fourth embodiment is the same as that of the first embodiment.

  The melt fiber content of the road surface side needle punch nonwoven fabric 13 and the floor side needle punch nonwoven fabric 13 is 40% by weight, and the non-melt fiber is 60% by weight.

  This Example 4 and the following Examples 5 to 13 were tested by using the material of Example 1 and changing the melt fiber content of the nonwoven fabric in order to compare the icing peel strength and chipping resistance. It is a thing.

(Example 5)
The core material 11 of the fifth embodiment is the same as that of the first embodiment.

  The melt fiber content of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was set to 60% by weight, and this content was the same as that of Example 1.

(Example 6)
The core material 11 of Example 6 is the same as that of Example 1.

  The melt fiber content of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was set to 70% by weight, and this content was the same as in Example 1.

(Example 7)
The core material 11 of Example 7 is the same as that of Example 1.

  The melt fiber content of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was set to 80% by weight, and this content was the same as in Example 1.

(Example 8)
The core material 11 of the eighth embodiment is the same as that of the first embodiment.

  The melt fiber content of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was set to 100% by weight, respectively, and was changed to Example 1 so as not to contain any non-melt fibers.

Example 9
In Example 9, based on Example 6, the basis weight of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was changed to 100 g / m ^2, and the influence of the change in the basis weight was examined.

(Example 10)
In Example 10, based on Example 6, the basis weight of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was changed to 300 g / m ^2, and the influence of the change in the basis weight was examined.

(Example 11)
In Example 11, based on Example 6, the basis weight of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was changed to 400 g / m ^2, and the influence of the change in the basis weight was examined.

(Example 12)
In Example 12, based on Example 6, the basis weight of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was changed to 500 g / m ² , and the effect of the change in the basis weight was examined.

(Example 13)
In Example 13, based on Example 6, the basis weight of each of the road surface side needle punched nonwoven fabric 13 and the floor side needle punched nonwoven fabric 13 was changed to 600 g / m ^2, and the influence of the change in the basis weight was examined.

(Comparative Example 1)
The core material of Comparative Example 1 uses basically the same material as in Example 1, but the molding method is significantly different from that in Example 1, and there are differences in the resulting products due to differences in manufacturing methods. . The difference as a product is that the stampable sheet constituting the first core layer 11a and the stampable sheet constituting the second core layer 11b have the same MD direction, and that the needle punched nonwoven fabric has a melting point of 250 ° C. The fiber is 100% by weight.

Molding of the core material of Comparative Example 1 will be described with reference to FIG. That is, in Comparative Example 1, the laminated member is heated and compressed using a hot press machine in a state in which a nonwoven fabric is laminated on the stampable sheet constituting the first core layer 11a and the stampable sheet constituting the second core layer 11b. The respective layers are bonded together, and then cold-pressed with a cold press to suppress foaming of the heat-expandable particles. Therefore, in this laminated member, as shown in FIG. 6A, at the time of this hot press and cold press, some of the heat-expandable particles are foamed small (the white small in FIG. 6A). Some of the heat-expandable particles are crushed by a hot press machine or a cold press machine so that the heat-expandable particles cannot be foamed (shown by a black circle 53b in FIG. 6A). Thereafter, as shown in FIG. 6B, the heat-expandable particles are expanded and expanded by heating again with a heater or the like. In this case, when heated again with a heater or the like, the remaining heat-expandable particles 53a foam to form bubbles as shown in FIG. The heat-expandable particles 53b that can no longer foam due to compression remain in a useless state. Here, the “useless state” is explained by the fact that the heat-expandable particles did not expand even when heated again due to the fact that they were crushed after being slightly expanded or collapsed without expanding. is there. From that state, it is molded into an undercover shape by the molding apparatus 30 similar to the present embodiment. Therefore, in the comparative example 1, as shown in FIG.6 (c), the heat-expandable particle | grains (bubble) which were expanded compared with FIG.5 (c) of a present Example become sparse, and are compression-molded. Further, a film similar to that of the conventional example is provided on the road surface side of the core material 11 of Comparative Example 1. Furthermore, about the core material 11 of the comparative example 1, on the characteristic of a manufacturing method, MD direction of the stampable sheet which comprises the 1st core layer 11a, and MD direction of the stampable sheet which comprises the 2nd core layer 11b Both stampable sheets are overlapped so that the two match. A protective film having a basis weight of 120 g / m ² and a basis weight of 60 g / m ² was used.

(Comparative Example 2)
Moreover, the comparative example 2 is different from the comparative example 1 in that the stampable sheet constituting the core material 11 has a single-layer structure and the basis weight thereof is 800 g / m ^2. This is the same as Comparative Example 1.

(Comparative Example 3)
Comparative Example 3 is based on Comparative Example 1, and the difference is that the protective film is omitted.

(Comparative Example 4)
Comparative Example 4 is based on Comparative Example 1, and the difference is that a protective film having a basis weight of 140 g / m ² and a basis weight of 60 g / m ² is provided.

  Next, various test methods and results will be described for Examples and Comparative Examples.

(Comparison of tensile strength: N, bending strength: N / 50 mm, elastic gradient: N / cm)
The tensile strength, bending strength, and elastic gradient of Examples 1 to 3 and Comparative Examples 1 and 2 were as shown in the table of FIG. Note that “vertical” in FIG. 7 is the vehicle front-rear direction when attached to the vehicle, and coincides with the MD direction. Further, “horizontal” means the vehicle width direction when attached to the vehicle, and coincides with the CD direction. Further, the “road surface” in the bending strength column is a case where the vehicle is bent toward the road surface (lower side), and the “vehicle” is a case where the vehicle is bent toward the vehicle side (upper side). The foam thickness is a thickness in a state where the foam is heated and foamed by a hot press machine, and the molded plate thickness is a thickness after molding with a cold press machine.

  Comparing the tensile strength, bending strength, and elastic gradient between Example 1 and Comparative Examples 1 and 2, it can be seen that Example 1 is a higher numerical value in all these three items. That is, the vehicle under cover 10 of the first embodiment is higher in rigidity than those of the first and second comparative examples. In Example 1, since the MD direction of the stampable sheet constituting the first core layer 11a and the MD direction of the stampable sheet constituting the second core layer 11b are substantially orthogonal, for example, in terms of tensile strength There is no significant difference between the vertical and horizontal values. Thereby, when it sees as the core material 11 whole, the difference of the intensity | strength of the vertical direction and a horizontal direction hardly arises, and it becomes difficult to cause the damage of the attachment part for attaching the undercover 10 to a vehicle.

  In Example 1, since the stampable sheets constituting the first core layer 11a and the first core layer 12a are integrally formed with the spunbond nonwoven fabric on one surface, the reinforcing fibers in the stampable sheet are The surface side formed integrally with the spunbond nonwoven fabric tends to be dense and sparse on the other surface side. Therefore, in Example 1, the two core materials 11a and 11b are overlapped with the other surfaces aligned with the surface side on which the spunbonded nonwoven fabric is integrally formed as the outside. By adopting this method, the difference in strength between the road surface side and the floor side is suppressed as much as possible, and it is difficult to cause warping of the molded product.

  The tensile strength, bending strength, and elastic gradient of Example 2 were as shown in the table of FIG. That is, compared with Example 1, in Example 2, the value in the longitudinal direction was higher than that in the transverse direction in terms of tensile strength, bending strength, and elastic gradient. That is, since the MD direction of the stampable sheet constituting the first core layer 11a and the MD direction of the stampable sheet constituting the second core layer 11b are both the longitudinal direction of the under cover 10, The difference from the horizontal direction is large.

  Moreover, when the tensile strength, bending strength, and elastic gradient of Example 2 and Comparative Examples 1 and 2 are compared, it can be seen that Example 2 is a higher numerical value in all these three items. That is, the vehicle under cover 10 of the second embodiment is higher in rigidity than that of the first comparative example.

Further, as shown in FIG. 8, when the basis weight of the stampable sheet constituting the core material 11 of the comparative example 1 is increased, the tensile strength increases approximately in proportion. For example, when the basis weight of the stampable sheet constituting the core material 11 of Comparative Example 1 is set to 800 g / m ² in total for the first core layer 11a and the second core layer 11b, the tensile strength becomes about 350 N and 1000 g in total. / M ² , the tensile strength is about 450N. On the other hand, the core material 11 of Example 2 has a total basis weight of 800 g / m ² of the first core layer 11a and the second core layer 11b, and this tensile strength is an average as shown in FIG. 475N. Therefore, as shown in FIG. 8, Example 2 corresponds to the tensile strength when the basis weight of the core material 11 of Comparative Example 1 is about 1000 g / m ² . In other words, in Example 2, the same tensile strength as in Comparative Example 1 can be obtained, but the basis weight can be reduced and the weight can be reduced.

The tensile strength, bending strength, and elastic gradient of Example 3 are as shown in the table of FIG. 7. In all three items of tensile strength, bending strength, and elastic gradient, Example 3 is more preferable than Comparative Examples 1 and 2. It turns out that it is a high number. That is, the vehicle under cover 10 of the third embodiment is higher in rigidity than those of the first and second comparative examples.

(Test method for icing peel test)
FIG. 9 schematically shows an icing force measuring apparatus 200. In this measuring apparatus 200, a sample S is sandwiched between a flat iron fixed substrate 201 and a substantially U-shaped iron pressing member 202, and ice 205 attached to the sample S in a stainless steel ring member 204 is pressed by a pressing member 203. It is an apparatus that measures the shear force required for shearing. As the ring member 204, a member made of SUS304 having an inner diameter of 50 mm, an outer diameter of 55 mm, and a height of 40 mm was used. In the test, the ring member 204 was placed on the sample S in which water was preliminarily soaked in a predetermined range on the surface of the road surface side needle punched nonwoven fabric, and the water was poured into the ring member 204 and frozen. Then, the sample S was sandwiched between the fixed substrate 201 and the pressing member 202 and fixed with bolts 206. The pressing member 203 was lowered toward the ring member 204 at a speed of 10 mm / min, and the maximum force applied to the pressing member 203, that is, the shearing force of the ice 205 attached to the sample S was measured. The above measurement was performed on samples prepared from Examples 4 to 13 and Comparative Examples 3 and 4.

(Chip resistance test)
The chipping resistance is a value obtained based on a chipping resistance test. The chipping resistance test is a test performed using 500 g of pebbles having a diameter of about 3 to 7 mm. Specifically, the sample of the vehicle under cover 10 is fixed in a state where the sample is set substantially vertically. Then, from a position 500 mm away from the surface of the road surface side needle punched nonwoven fabric 13 in this sample, 500 g of pebbles are injected toward the surface of the road surface side needle punched nonwoven fabric 13 by compressed air of 0.6 MPa. This was performed once until the road surface side needle punched nonwoven fabric 13 was broken, and the number of times was measured. The above measurement was performed on samples prepared from Examples 4 to 13 and Comparative Examples 3 and 4.

FIG. 10 shows the results of measuring the value of the icing peel force and the chipping resistance. In Example 4, the value of the icing peeling force is 40 N, and the chipping resistance is 115 times. In Example 5, the value of the icing peel strength is 30 N, and the chipping resistance is 110 times. In Example 6,
The value of the icing peel strength is 28N, and the chipping resistance is 110 times. In Example 7, the value of the icing peel force is 25 N, and the chipping resistance is 100 times. In Example 8, the value of the icing peel strength is 22 N, and the chipping resistance is 85 times. In Example 9, the value of the icing peel strength is 32 N, and the chipping resistance is 95 times. In Example 10, the value of the icing peel strength is 23 N, and the chipping resistance is 130 times. In Example 11, the value of the icing peel strength is 22 N, and the chipping resistance is 150 times. In Example 12, the value of the icing peel strength is 21 N, and the chipping resistance is 160 times. In Example 13, the value of the icing peel force is 21 N, and the chipping resistance is 175 times. On the other hand, in Comparative Example 3, the value of the icing peel force is 48 N, and the chipping resistance is 60 times. In Comparative Example 4, the value of the icing peel strength is 27N, and the chipping resistance is 125 times. That is, in Examples 4 to 13, the value of the icing peel strength is 40 N or less, excellent icing peel performance, chipping resistance of 80 times or more, and excellent chipping resistance. On the other hand, in Comparative Example 3, the value of the icing peeling force and the chipping resistance could not satisfy the above numerical values and were insufficient. Further, Comparative Example 4 shows the same excellent value as in this example in the value of the icing peel force and the chipping resistance, but it was an average good value because of the average of 10 samples. Looking at the entire cover, some of the film was thin, and some felt the rough feel of the nonwoven fabric, and stable performance was not obtained with the entire undercover. In addition, since it is necessary to interpose a film separately, the assemblability is inferior and the cost is increased. As will be described later, good results were not obtained in terms of noise prevention performance such as sound absorption.

  In addition, as shown in FIG. 10, in Examples 4-13, when the melt fiber was increased, the value of icing peeling force became low and it became easy to peel ice. The reason for this is that as the melt fiber content increases, the smoothness of the road surface side of the road surface side needle punched nonwoven fabric 13 improves due to melting of the melt fiber during the heat forming of the core material 11, and ice is formed when the ice is icing. This seems to be because it becomes easier to peel off. On the other hand, when the content of the melt fiber of the road surface side needle punched nonwoven fabric 13 increases, the portion remaining as a fiber in the needle punched nonwoven fabric 13 due to melting of the melt fiber at the time of thermoforming the core material 11 decreases, and the cushioning property is increased. It seems that the chipping resistance gradually decreased and the chipping resistance gradually decreased. However, the chipping resistance tends to decrease slightly, but it is within a satisfactory range, and there was no problem even if the content of the melt fiber was increased.

  As described above, the icing peel strength and chipping resistance can be adjusted by the melt fiber content of the road surface side needle punched nonwoven fabric 13. Judging from the results of Examples 4 to 13, it is preferable that the content of the melt fiber of the road surface side needle punched nonwoven fabric 13 is 60% by weight or more from the viewpoint of the value of the icing peel force, and the chipping resistance. From this point of view, it was preferable that the content of the melt fiber of the road surface side needle punched nonwoven fabric 13 be 80% by weight or less. From this result, it can be judged that a melt fiber content of 60 to 80% is particularly preferable.

Further, as shown in FIG. 10, the road surface side needle punch is relatively compared between the sixth embodiment and the six embodiments of Examples 9 to 13 in which the basis weight of the road surface side needle punch nonwoven fabric 13 is changed on the basis thereof. When the weight per unit area of the nonwoven fabric 13 was decreased, both icing and chipping resistance were slightly deteriorated, and when the basis weight was increased, icing and chipping characteristics were slightly improved. However, both values were acceptable for practical use. As a practical range, the basis weight of the road surface side needle punched nonwoven fabric 13 is preferably 100 to 500 g / m ^2, and particularly preferably 150 to 250 g / m ² .

  Moreover, the sound absorption characteristic of noise changes by changing the fabric weight and melt fiber content of the road surface side needle punch nonwoven fabric 13. This will be described with reference to FIGS.

FIG. 11 is a graph showing the relationship between the reverberation chamber method sound absorption rate according to JIS A 1409 and the basis weight of the road surface side needle punched nonwoven fabric 13 and the reverberation chamber method sound absorption rate of Comparative Example 1 in Examples. In this example, a1 is 70% by weight of the melt fiber, a2 is an average sound absorption coefficient of 1 to 2 kHz band of the melt fiber of 100% by weight, b1 is 70% by weight of the melt fiber, and b2 is 500 to 800 Hz of 100% by weight of the melt fiber. The average sound absorption coefficient in the band of 500 to 800 Hz in h1 is Comparative Example 1 (weight per unit area of the needle punched nonwoven fabric: 120 g / m ² + weight per unit area of the protective film: 60 g / m ² ), h2 Indicates an average sound absorption coefficient in a band of 1 to 2 kHz. In the present embodiment, when the basis weight of the road surface side needle punched nonwoven fabric 13 is simply reduced, the sound absorption coefficient in the 1-2 kHz band is slightly improved, and the sound absorption coefficient in the 500-800 Hz band is slightly decreased. On the other hand, when the basis weight of the road surface side needle punched nonwoven fabric 13 is simply increased, the sound absorption coefficient in the band of 1 to 2 kHz is gradually decreased, and the sound absorption coefficient in the band of 500 to 800 Hz is gradually improved. That is, it can be seen that the basis weight should be adjusted depending on what frequency band the sound absorption coefficient is given priority. However, the sound absorption rate of Comparative Example 1 was 38.9% on the average of 1 to 2 kHz, and 50% on the average sound absorption rate of 500 to 800 kHz. As shown in FIG. 11, when the basis weight of the nonwoven fabric exceeds 500 g / m ² , the average sound absorption rate of ¹ to ² kHz tends to deteriorate rapidly, and the basis weight of the nonwoven fabric as in Example 13 is 600 g. / M ² is not preferable because the average sound absorption coefficient of 500 to 800 kHz becomes 50% or less and the weight also increases. On the other hand, if it is less than 100 g / m ² , the average sound absorption coefficient at 500 to 800 kHz is 40% or less, which is not preferable. Therefore, when importance is attached to sound absorption characteristics, the basis weight is preferably set to 100 to 500 g / m ² .

  FIG. 12 is a graph showing the relationship between the reverberation chamber method sound absorption rate according to JIS A 1409 and the melt fiber content of the road-side needle punched nonwoven fabric 13 and the reverberation chamber method sound absorption rate of Comparative Example 1. The case where the amount of melt fiber was changed in Example 6 and Comparative Example 1 were compared. In this example, when the melt fiber is changed with an average sound absorption coefficient in a band of a1 to 2 kHz, b1 shows a case where the melt fiber is changed with an average sound absorption coefficient in a band of 500 to 800 Hz, and h1 is Comparative Example 1. The average sound absorption coefficient in the band of 500 to 800 Hz (without melt fiber) and the average sound absorption coefficient in the band of h2 of 1 to 2 kHz are shown. The sound absorption coefficient of Comparative Example 1 was 38.9% on the average of 1 to 2 kHz, and 50% on the average of 500 to 800 Hz. On the other hand, in this example, when the melt fiber content of the road surface side needle punched nonwoven fabric 13 is increased, the average sound absorption coefficient in the band of 1 to 2 kHz has almost no effect and is almost 70% or more, and the band of 500 to 800 Hz. The average sound absorption rate gradually increases. However, when the melt content is less than 40%, the average sound absorption coefficient in the band of 500 to 800 Hz is about 45%. From the viewpoint of stably securing the average sound absorption coefficient of 40% or more, the melt content is 40% or more. It is preferable that

In addition, from the result of FIG.11 and FIG.12, when reducing pattern noise (1 to 2 kHz average sound absorption rate) effectively, for example, when making 1 to 2 kHz average sound absorption rate 70% or more, for example. melt fibers in the nonwoven fabric is 40 to 100%, basis weight of the nonwoven fabric is preferably set to 100 to 200 g / m ^2.

  Therefore, by changing the basis weight and the melt fiber content of the road surface side needle punched nonwoven fabric 13, it is possible to improve the sound absorption coefficient in the band of 1 to 2 kHz or improve the sound absorption coefficient in the band of 500 to 800 Hz. Therefore, the sound absorption characteristic of the vehicle undercover 10 can be a sound absorption characteristic suitable for the vehicle.

  Furthermore, regarding Example 1 and Comparative Example 1, assuming that the under cover is attached to the under body in a case where it is actually attached to the vehicle, the case where the under cover is attached with a gap (air gap) therebetween. The sound absorption rate was compared. The result is shown in FIG.

  When there is no air layer on the floor side of the vehicle undercover 10 (air gap 0 mm), the example is J1, the comparative example is H1, the example when the air gap is 20 mm is J2, the comparative example is H2, and the air FIG. 13 shows an example in which the gap is 80 mm as J3 and a comparative example as H3. As shown in FIG. 13, J1, J2 of Example 1 in which melt fibers were provided to H1, H2, and H3 of Comparative Example 1 of the conventional method having a film on the road surface side and needle punched nonwoven fabric 13 on the back surface side to eliminate the film. In comparison with J3, even when the air gap was zero or when the air gap was provided, Example 1 was able to obtain a higher sound absorption rate with pattern noise (1-2 kHz). In addition, in J1, J2, and J3 of Example 1, the noise reduction effect in a band of 1 kHz or more is particularly enhanced when the air gap is wide, and the quietness of the passenger compartment can be enhanced. That is, when the under cover is actually mounted on a vehicle, an air gap often exists. Therefore, it is a good tendency that the air gap is provided, and the practicality is excellent.

  A modification of the present embodiment shown in FIG. 1 will be described with reference to FIG. FIG. 14 corresponds to FIG. 3B of the present embodiment. In the modification, only points different from the present embodiment will be described, and common points will be omitted.

  In the present embodiment, the core material 1 (11) is formed by laminating the first core layer 1a (11a) and the second core layer 1a (11b), but in the modification of FIG. The 1-core layer 1a (11a) and the second-core layer 1a (11b) are partially overlapped, and most of them are the first-core layer 1 (11a) and the second-core layer 1a (11b). It has become. Since the portion where the first core layer 1a (11a) and the second core layer 1a (11b) overlap has a relatively good result in performance as compared with the portion which does not overlap, higher performance is required. It is preferable to provide this overlapping portion in the portion. For example, it is preferable that the overlapping portion is provided in a portion where the under cover is attached to the vehicle body.

  In this modification, the floor-side spunbond nonwoven fabric 1b (14) is bonded to the floor-side surface (upper surface) of the first core layer 1a (11a), and is manufactured as an integral stampable sheet. Since the road surface side spunbond nonwoven fabric 1b (12) is bonded to the road surface side (lower surface) of the layer 1a (11b) and manufactured as an integral stampable sheet, the stampable sheet is partially overlapped. The needle punched nonwoven fabrics 1c, 1c (13, 15) to be overlaid on these were manufactured so that both the portion where the stampable sheet overlapped and the portion which did not overlap were covered with one sheet.

  In addition, you may make it overlap with the stampable sheet only of a core material, and may make it overlap partially after providing a needle punch nonwoven fabric integrally.

  When a part of two stampable sheets is overlaid, as shown in FIG. 14, the side where the floor-side spunbond nonwoven fabric 1b (14) is not provided and the side where the road surface side spunbond nonwoven fabric 1b (12) is not provided The first core layer 1a (11a) and the second core layer 1a (11b) may be overlapped with each other, but the first core layer 1a (11a) is placed on the floor-side spunbond nonwoven fabric 1b (14). When it is made to overlap with the 2nd core layer 1a (11b) by making the road surface side into, the floor side span of the road surface side spunbond nonwoven fabric 1b (12) of the 1st core layer 1a (11a) and the 2nd core layer 1a (11a) Since the bond nonwoven fabric 1b (14) is arranged on the road surface side, it is advantageous that a similar structure can be obtained by laminating the needle punch nonwoven fabric thereon.

  Also, two of the present embodiment may be prepared and partially overlapped as in this modified example, and the core material may be partially divided into two layers and one layer. It is possible to overlap. In some cases, overlapping portions may be formed at a plurality of locations instead of one.

  In addition, when overlapping, it may laminate | stack so that the flow direction at the time of manufacture of a core material may mutually cross, and the same direction may be sufficient.

  In the present invention, the layers constituting the core material 11 are one layer and two layers, but may be three layers or more.

  As described above, the vehicle undercover according to the present invention can be used by being attached to, for example, the lower surface of the floor of an automobile.

DESCRIPTION OF SYMBOLS 10 Undercover 11 for vehicles 11 Core material 12 Road surface side spunbond nonwoven fabric 13 Road surface side needle punch nonwoven fabric 14 Floor side spunbond nonwoven fabric 15 Floor side needle punch nonwoven fabric 20 Hot press apparatus 30 Molding apparatus

Claims (6)

  A vehicular undercover provided to cover a lower surface of a vehicle floor, comprising a stampable sheet in which a thermoplastic resin, reinforcing fibers, and heat-expandable particles are dispersedly dispersed, and is heat-molded along the lower surface of the floor And a nonwoven fabric laminated on the road surface side of the core material and integrally formed with the core material, wherein the nonwoven fabric contains, as constituent fibers, melt fibers that melt at the heating temperature of the core material. Under cover for vehicles.   The undercover for a vehicle according to claim 1, wherein the nonwoven fabric contains 40 to 100% by weight of the melt fiber and 0 to 60% by weight of non-melt fiber that does not melt at the heating temperature of the core material. Under cover for vehicles. The vehicle undercover according to claim 1 or 2, the weight per unit area of the nonwoven fabric is undercover for a vehicle, which is a 100 to 500 g / m ^2.   The undercover for vehicles according to any one of claims 1 to 3, wherein the core includes a first core layer and a second core layer, and the first core layer, the second core layer, Are laminated so that the fiber flow directions of the reinforcing fibers at the time of production of these core layers intersect each other.   Prepare a stampable sheet containing thermoplastic resin, reinforcing fibers, and heat-expandable particles in a dispersed manner, and overlay the nonwoven fabric on this stampable sheet, and then heat-compress with a flat plate hot press to form the nonwoven fabric on the surface of the stampable sheet. After pressing to produce a sticking member in which the nonwoven fabric is stuck to the stampable sheet, a hot press machine is opened to expand the heat-expandable particles in the stampable sheet of the heated sticking member to a predetermined thickness. A method for manufacturing an undercover for a vehicle, comprising: forming an inflatable sticking member; and thereafter, forming the inflatable sticking member into a cold press and press-molding to form a vehicle undercover.   In the manufacturing method of the undercover for vehicles of Claim 5, in a hot press machine, a stampable sheet and a nonwoven fabric are heated at 160-220 degreeC, and are compressed to the thickness of 0.7-2.5 mm, A method for manufacturing an undercover for a vehicle, which is held for 30 seconds.