JP4630155B2 - Interior material for automobile having uneven shape and manufacturing method thereof - Google Patents

Description

The present invention relates to an interior material for automobiles having a concavo-convex shape that is laid in a vehicle compartment of an automobile and a method for manufacturing the same.

  A molded product made of resin or fiber is laid as an interior material on a panel constituting a passenger compartment or a cargo compartment of an automobile. Such interior materials provide design and cushioning and feel suitable for interior materials, play a role as raising materials such as ensuring flatness of the floor, and reduce transmission of sound waves and heat. It has a function to do.

As shown in FIG. 6, Patent Document 1 discloses that a sound insulating layer 2 made of a resin layer or a fiber layer impregnated with a resin on the lower surface of a skin layer 1 made of a fibrous material, and a vibration damping / sound absorbing layer made of felt. 3 is sequentially stacked. Since the sound insulating layer 2 is made of a resin layer or a fiber layer impregnated with a resin, the sound insulating layer 2 is non-breathable.
Japanese Patent No. 2622086

Various noises such as road noise, engine noise, wind noise, and the like that are generated when the automobile travels on the road try to enter the passenger compartment. With the technique described in Patent Document 1, noise that attempts to enter the vehicle interior from outside the vehicle is reduced to some extent. However, since the sound insulation layer 2 is air-impermeable, noise that has entered the vehicle interior is reflected by the sound insulation layer 2 as shown by the arrows in FIG. It was not able to be made and sound was not absorbed. In order to further improve the quietness of the passenger compartment, it has been required to develop an interior material for automobiles that has a sound absorbing function against noise that has entered the passenger compartment.
In addition, since the panels constituting the passenger compartment and the luggage compartment are not flat but have an uneven shape, the interior material laid on these panels is also shaped to follow the uneven shape of the panel. For this reason, in particular at a bent portion where deep drawing deformation is required, it is necessary to have good shapeability as well as to maintain a desired shape after forming. However, in the technique described in the cited document 2, since only the sound insulating layer 2 provides strength and shape retention to the laminate, the rigidity is insufficient and the required shape cannot be sufficiently maintained after molding. was there.

The present invention has been made in view of the above problems, and in an interior material for an automobile having an uneven shape, it is possible to sufficiently prevent sound from entering from the outside of the vehicle and sufficiently absorb sound that has entered the vehicle interior. An object of the present invention is to provide an automobile interior material that can improve rigidity while being lightweight, and has excellent shape retention properties that can maintain a required shape even after molding.

In order to achieve the above object, the present invention is an automotive interior material having an uneven shape, which is laid in a passenger compartment of an automobile, and is a ventilation system in which fibers are gathered at a weight of 500 to 1500 g / m ² per unit area. A sound-absorbing layer and a non-breathable thermoplastic sheet having a weight per unit area of 30 to 1000 g / m ^2, and provided on the outer surface of the vehicle on the opposite side to the vehicle compartment side with respect to the sound-absorbing layer. And 20 to 95% by weight of the base fiber and 5 to 80% by weight of the crosslinking fiber, which are thermoplastic fibers, are aggregated and thermoformed on the sound insulation layer and the surface of the sound absorbing layer on the passenger compartment side. A breathable reinforcing layer formed by thermoforming in accordance with the shape of the uneven vehicle body panel in a laminated state, the sound absorbing layer and the sound insulating layer are in contact, and the thickness of the sound absorbing layer Is 2.0 to 10.0 mm, and the thickness of the sound insulation layer is 0.03 to 0.03 mm. .0Mm, air permeability of the reinforcing layer is 5cc / cm ² / sec or more, and having an irregular shape.
The automotive interior material having an uneven shape has a non-breathable sound insulation layer, a breathable sound absorption layer, and a breathable reinforcement layer formed in order from the vehicle exterior side to the vehicle compartment side, and the sound absorption layer and the sound insulation layer are It touches . Sound that tries to enter from the outside of the vehicle is reflected by the non-breathable sound insulation layer and blocked from passing into the passenger compartment. On the other hand, since the reinforcing layer formed on the vehicle interior side has air permeability, sound that has entered the vehicle interior passes through the reinforcing layer and enters the air-permeable sound absorbing layer to be absorbed. As a result, the intrusion of sound from outside the vehicle can be sufficiently prevented, the sound that has entered the vehicle interior can be sufficiently absorbed, the noise that enters the passenger's ears can be effectively reduced, and the quietness of the vehicle can be reduced. Can be improved.
In addition, a lightweight sound absorbing layer in which fibers are assembled is sandwiched between a sound insulating layer made of a thermoplastic sheet and a reinforcing layer formed from fibers, and is thermoformed. As a result, good shape-retaining properties that keep the required shape after molding can be obtained.

  The fibers of the reinforcing layer are composed of a base material fiber, a thermoplastic core fiber, and a sheath fiber formed on the outer periphery of the core fiber and having a melting point lower than that of the core fiber. It is also possible to use a fiber blended with a core-sheath structure crosslinking fiber. Even if the sheath fiber is heated and melted, the core fiber having a melting point higher than that of the sheath fiber is not easily melted by heating. Therefore, the core-sheath-structured crosslinking fiber bridges the base material fibers to impart rigidity.

The interior material for automobiles may be an interior material that is thermoformed by laminating only a sound insulation layer, a sound absorbing layer, and a reinforcing layer, or may be an interior material that is thermoformed by laminating a skin layer or a backing layer.
When a breathable skin layer in which fibers are gathered is provided on the surface of the reinforcing layer on the passenger compartment side, the skin layer has air permeability, so that sound entering the passenger compartment passes through the skin material and enters the sound absorbing layer. Therefore, the sound absorbing performance for absorbing sound and absorbing the sound in the passenger compartment can be maintained. Moreover, since the surface on the passenger compartment side is a skin layer in which fibers are gathered, a design suitable as an interior material is given.

Moreover, this invention is a manufacturing method of the interior material for motor vehicles for manufacturing the interior material for motor vehicles which has the uneven shape laid in the compartment of a motor vehicle, Comprising: The weight per unit area 500-1500 g / m < ² >. A breathable sound-absorbing layer in which fibers are gathered together , 20 to 95% by weight of base material fiber and 5 to 80% by weight of cross-linking fiber which is a thermoplastic fiber on the surface of the sound absorbing layer on the passenger compartment side And a breathable reinforcing layer formed by thermoforming and forming a laminate by heating and melting the thermoplastic fibers constituting the reinforcing layer by supplying hot air by needling at least overlapping A sound insulating layer formed of a non-breathable thermoplastic sheet having a weight per unit area of 30 to 1000 g / m ² and provided on the outer surface of the vehicle opposite to the vehicle compartment side with respect to the sound absorbing layer; , Weight per unit area 15-100g A laminated body in which the backing layer and the sound insulation layer are bound to each other by melting the thermoplastic sheet constituting the sound insulation layer by radiating and heating the backing layer made of a nonwoven fabric of / m ² The sound absorbing layer and the sound insulating layer connect the sound insulating layer side of the binder and the sound absorbing layer side of the laminated body in a mold that is shaped to match the shape of the uneven body panel. By overlapping and clamping in a contact state and thermoforming , the thickness of the sound absorbing layer is 2.0 to 10.0 mm, the thickness of the sound insulating layer is 0.03 to 1.0 mm, and the air permeability of the reinforcing layer is It is characterized by producing an interior material for an automobile having an uneven shape that is 5 cc / cm ² / sec or more .

With the above configuration, since the sound absorbing layer and the reinforcing layer are fixed to each other by needling, a laminate can be easily formed by supplying hot air, and the sound insulating layer made of a thermoplastic sheet is melted by radiation heating. Even if the backing layer does not sag or deform, the binder can be easily formed, and the heat-melted thermoplastic sheet can be handled easily, so that the backing layer, the sound insulation layer and the sound absorbing layer It is possible to easily manufacture an automobile interior material having an uneven shape in which a layer and a reinforcing layer are laminated.

According to the invention according to claim 1, in the interior material for an automobile having an uneven shape , it is possible to sufficiently prevent sound from entering from the outside of the vehicle and to sufficiently absorb the sound that has entered the vehicle interior, and is lightweight. However, it is possible to provide an interior material for automobiles that can improve the rigidity and has excellent shape retention property that can maintain a required shape even after molding .

In the invention according to claim 2 , the thermoplastic sheet is prevented from being drooped or deformed by the backing layer when the sound insulation layer made of the thermoplastic sheet is brought into the mold in the state of being heated and melted. It is possible to significantly improve the handling performance .

In the invention according to claim 3 , in the method for manufacturing an interior material for an automobile having an uneven shape, the reinforcing layer and the sound absorbing layer can be heated almost uniformly up to the inside of the laminate by hot air heating, and also non-breathable. Since the layer composed of the resin sheet and the nonwoven fabric layer can be heated uniformly by radiation heating, there is no bias in the heating temperature in each layer, and a method for producing a high-quality automotive interior material excellent in moldability is provided. Can do.

Hereinafter, embodiments of the present invention will be described in the following order.
(1) Composition of automotive interior materials:
(2) Manufacturing method of automotive interior materials:
(3) Functions and effects of automotive interior materials:
(4) Modification:
(5) Example:

(1) Composition of automotive interior materials:
FIG. 1 is a front view showing a partial cross-sectional view of the main part of the interior of a road traveling vehicle 200 laid with the automobile interior materials 108 and 109 of the present invention, and FIG. 2 is a vertical view of the main part of the vehicle interior material 100. It is a figure shown in a cross section.
The main road traveling vehicle 200 is provided with doors 110, 110, a floor panel 120, and a ceiling panel (not shown) that form a vehicle body, and seats 130, 130 are provided in the passenger compartment SP1. The doors 110 and 110 are made of a metal door outer panel (a kind of vehicle body panel) 112 and 112, or a metal door inner panel (a kind of vehicle body panel) 114 disposed closer to the passenger compartment than the door outer panel. 114 and window glass 116, 116, and automobile interior materials 108, 108 laid on the vehicle interior side with respect to the door inner panels 114, 114. On the floor panel 120, an automobile interior material 109 for a floor surface is laid.

These interior materials 108 and 109 are in a state in which at least a non-breathable sound insulation layer 40, a breathable sound absorbing layer 30, and a breathable reinforcement layer 20 are laminated, as in the case of an automotive interior material 100 shown in FIG. It is obtained by thermoforming according to the shape of the passenger compartment SP1. In the interior material 100 of the present embodiment, a backing layer 50 is further provided on the surface of the sound insulation layer 40 on the vehicle outer side (opposite to the vehicle compartment side), and a breathable skin is provided on the vehicle interior side surface of the reinforcing layer 20. The layer 10 is provided and is formed by thermoforming in a state where the layers 10 to 50 are laminated. Here, the interior material 100 is not flat but is formed in an uneven shape. Further, when the interior material is laid on the uneven body panel, the interior material is formed in a shape following the uneven shape of the panel.

  The skin layer 10 is a thin surface layer provided on the surface on the passenger compartment side for the purpose of imparting design as an interior material, and is formed so as to have a breathability by collecting a large number of fibers. As a result, the design of the passenger compartment can be improved while maintaining good sound absorption. Fibers used for the skin layer include thermoplastic resin fibers, fibers obtained by adding additives such as fillers to thermoplastic resins, polyester, polyamide, acrylic, polypropylene (PP), polyethylene (PE), polychlorinated Use fibers made of resin such as vinyl, polyvinylidene chloride, acetate, polyethylene terephthalate (PET), or fibers made by adding additives such as fillers to these resins (for example, less blending ratio than resin). Can do. Further, it is more preferable to use fibers formed by composing these resins so as to have a relatively high melting point. Since the skin layer is disposed on the indoor side of the automobile, it is more preferable to use a fiber having high design properties such as a dyed fiber or a crimped fiber as the constituent fiber. When a skin layer is formed using these designable fibers, the appearance of the automotive interior material 100 can be improved.

In addition, it is preferable to use a needle punched nonwoven fabric for the skin layer because an interior material with a good appearance can be obtained and a good sound absorption can be obtained. Is preferably a weight per unit area of the nonwoven fabric to 100 to 500 g / m ² is used as a skin layer, more preferably to the 150 and 400 / m ^2. If the weight per unit area is not less than the above lower limit, good strength can be obtained as a skin layer and good appearance can be obtained, and if the weight per unit area is not more than the above upper limit, good air permeability can be obtained. It is. The thickness of the needle punched nonwoven fabric used as the skin layer is preferably 0.5 to 8 mm, and more preferably 1 to 5 mm. This is because when the thickness is set to the lower limit or more, good strength is obtained and a good appearance is obtained, and when the thickness is set to the upper limit or less, good air permeability is obtained. Generally, the thickness of the skin layer can be determined in the range of 0.5 to 15 mm (more preferably 1 to 10 mm).
If the air permeability of the nonwoven fabric used for the skin layer (according to the fragile method defined in JIS L1096, hereinafter the same) is set to a high air permeability of 5 cc / cm ² / sec or more, the sound absorption is remarkably improved. This is because the sound wave traveling from the vehicle interior to the sound absorbing layer 30 is hardly reflected by the highly breathable skin layer 10, and sound energy is sufficiently absorbed by the sound absorbing layer. It is presumed that the sound absorption is not lowered. In order to adjust the air permeability of the skin layer, the weight and thickness per unit area may be adjusted. If the weight per unit area of the skin layer is reduced or the thickness is reduced, the air permeability is increased. Can be made.
Alternatively, the skin layer may be formed by using the fiber of the above-mentioned material as the base material fiber for the skin layer and adding a thermoplastic fiber for the skin layer different from the base material fiber. As the thermoplastic fiber for the skin layer, a fiber of a thermoplastic resin, a fiber in which an additive such as a filler is added to the thermoplastic resin, etc. can be used, as in the case of the crosslinking fiber of the reinforcing layer described later. Fibers made of thermoplastic resins such as polyolefins such as PP, polyesters, polyamides, fibers made of thermoplastic resins whose melting points are adjusted by modifying these thermoplastic resins, and additives such as fillers for these thermoplastic resins ( For example, fibers of a material to which a blending ratio less than that of a resin is added, fibers having a core-sheath structure composed of a core fiber and a sheath fiber with these materials, and the like can be used. The blending ratio of the skin layer base fiber and the skin layer thermoplastic fiber is 80 to 99% by weight of the skin layer base fiber, 1 to 20% by weight of the skin layer thermoplastic fiber, and the skin layer heat. It is preferable to make the blending ratio of the plastic fibers smaller than the blending ratio of the crosslinking fibers in the reinforcing layer.

The reinforcing layer 20 is a thin intermediate layer provided for the purpose of imparting rigidity to maintain the shape after molding, and thermoforming by collecting a large number of fibers having at least thermoplastic fibers on the surface of the sound absorbing layer 30 on the passenger compartment side. Thus, it is formed to have air permeability. The fibers used in the reinforcing layer may all be thermoplastic fibers, or may be fibers obtained by mixing thermoplastic fibers such as glass fibers, carbon fibers, rayon fibers and the like that do not exhibit thermoplasticity. The thermoplastic fibers used for the reinforcing layer include thermoplastic fibers, fibers obtained by adding additives such as fillers to thermoplastic resins, and thermoplastics such as polyolefins such as PE and PP, polyesters, polyamides, and PET. Fibers made of resin, fibers made of thermoplastic resins whose melting points are adjusted by modifying these thermoplastic resins, and materials in which additives such as fillers (for example, less blending ratio than resin) are added to these thermoplastic resins Fiber, etc. can be used.
The fibers of the reinforcing layer of the present embodiment are fibers in which base material fibers and crosslinking fibers that are thermoplastic fibers are blended. The crosslinking fiber of this embodiment is composed of a thermoplastic core fiber and a sheath fiber formed on the outer periphery of the core fiber and having a melting point lower than that of the core fiber. The core-sheath structure is a thermoplastic fiber.

The base fiber is used for imparting sufficient rigidity to the reinforcing layer. The base fiber can be a fiber of thermoplastic resin, a fiber in which an additive such as a filler is added to a thermoplastic resin, polyester fiber, PP fiber, polyamide fiber, rayon fiber, PET fiber, and further filler A fiber made of a material to which an additive such as a material (for example, a blending ratio less than that of the resin) is added can be used. As the base fiber, it is preferable to use a fiber having a good adhesion property to the crosslinking fiber. For example, a fiber compatible with the crosslinking fiber (a sheath fiber in the case of a fiber having a core-sheath structure) is used for crosslinking. Adhesiveness with the fibers for use becomes good, and sufficient rigidity can be imparted to the reinforcing layer. Fibers of the same material may be used as the fibers compatible with the crosslinking fibers.
The fiber diameter of the base fiber is preferably 5 to 60 μm, and more preferably 5 to 35 μm. Further, the fiber length of the base fiber is preferably 10 to 100 mm, and more preferably 24 to 64 mm. When the fiber diameter and fiber length are within these ranges, it becomes difficult to form a fiber lump when producing the interior material, and processability is improved, such as good dispersibility in the carding process.

The crosslinking fiber is used for imparting sufficient rigidity to the reinforcing layer by crosslinking the base material fibers. For the fiber for crosslinking, a fiber of a thermoplastic resin, a fiber obtained by adding an additive such as a filler to the thermoplastic resin, and the like can be used. The fiber includes a thermoplastic resin such as a polyolefin such as PE or PP, a polyester, or a polyamide. Fibers, fibers made of a thermoplastic resin whose melting point is adjusted by modifying these thermoplastic resins, fibers made of a material obtained by adding an additive such as a filler (for example, a blending ratio less than the resin) to these thermoplastic resins, Etc. can be used. For the cross-linking fiber, use a thermoplastic fiber having a property of good adhesion to the base fiber and a lower melting point than that of the base fiber when the base fiber is a thermoplastic fiber. Preferably, for example, when a fiber compatible with the base material fiber is used, the adhesion to the base material fiber is improved and sufficient rigidity can be imparted to the reinforcing layer.
The melting point of the crosslinking fiber is preferably 100 to 220 ° C. This is because when the melting point is equal to or higher than the lower limit, it is possible to impart good rigidity to the reinforcing layer without any problem in practical heat resistance, and when the melting point is equal to or lower than the upper limit, sufficient adhesion to the base fiber during thermoforming is sufficient. It is because it can be obtained and good rigidity can be imparted to the reinforcing layer.

A core-sheathed fiber formed by surrounding the core fiber with a low-melting component or medium-melting component in a sheath shape, that is, heat melting with a sheath fiber consisting of a core fiber and a low-melting fiber having a lower melting point than the core fiber. When a fiber having an adhesive core / sheath structure is used as a fiber for cross-linking, the above-mentioned materials for the sheath fiber, that is, fibers of thermoplastic resin such as polyolefin, polyester, polyamide, etc., and these thermoplastic resins are modified to have a melting point. Fibers made of the adjusted thermoplastic resin, fibers made of a material obtained by adding an additive such as a filler (for example, a blending ratio less than the resin) to these thermoplastic resins, and the like can be used. For the sheath fiber, it is preferable to use a thermoplastic low-melting-point fiber or medium-melting-point fiber having a good property of bonding with the base material fiber and having a melting point lower than that of the base material fiber. When a low-melting fiber or a medium-melting fiber having compatibility with the fiber is used, the adhesion with the base material fiber is improved, and sufficient rigidity can be imparted to the reinforcing layer.
The melting point of the sheath fiber is preferably 100 to 220 ° C. This is because when the melting point is equal to or higher than the lower limit, it is possible to impart good rigidity to the reinforcing layer without any problem in practical heat resistance, and when the melting point is equal to or lower than the upper limit, sufficient adhesion to the base fiber during thermoforming is sufficient. It is because it can be obtained and good rigidity can be imparted to the reinforcing layer.

For the core fiber, a thermoplastic resin having a melting point higher than that of the sheath fiber is used, but like the sheath fiber, fibers of thermoplastic resins such as polyolefin, polyester, polyamide, etc., and these thermoplastic resins are modified to lower the melting point. Fibers made of the adjusted thermoplastic resin, fibers made of a material obtained by adding an additive such as a filler (for example, a blending ratio less than the resin) to these thermoplastic resins, and the like can be used.
The melting point of the core fiber is preferably 160 to 260 ° C. This is because when the amount is equal to or more than the lower limit, cutting due to melting is less likely to occur during thermoforming, and good rigidity can be imparted to the reinforcing layer.

  The fiber diameter of the crosslinking fiber is preferably 8 to 45 μm. This is because when the fiber diameter is set to the above lower limit or more, the reinforcing layer can be given good rigidity without any problem in dispersibility in the carding step. When the fiber diameter is set to the upper limit or less, the cross-linking fiber per unit weight This is because the number of the fibers increases so that the base fibers can be sufficiently cross-linked to give the reinforcing layer good rigidity. The fiber length of the crosslinking fiber is preferably 10 to 100 mm. This is because when the fiber length is equal to or greater than the above lower limit, there is no dropout of fibers in the carding step, and the base fiber can be sufficiently cross-linked to impart good rigidity to the reinforcing layer. Then, it is difficult to form a fiber lump when producing the interior material, and processability is improved, such as good dispersibility in the carding process.

The mixing ratio of the base fiber and the crosslinking fiber is 20 to 95% by weight of the base fiber (more preferably 30 to 95% by weight, more preferably 50 to 95% by weight), and 5 to 80% by weight of the crosslinking fiber. % (More preferably 5 to 70% by weight, still more preferably 5 to 50% by weight). This is because if the blending ratio of the cross-linking fibers is equal to or higher than the lower limit, the base fiber can be sufficiently cross-linked to give the reinforcing layer good rigidity, and if the blending ratio of the cross-linking fibers is equal to or lower than the upper limit. This is because there is almost no shrinkage after thermoforming and the product is not deformed.
When the air permeability of the reinforcing layer is set to a high air permeability of 5 cc / cm ² / sec or more, the sound absorption is remarkably improved. This is because the sound wave traveling from the passenger compartment to the sound absorbing layer 30 is hardly reflected by the highly breathable reinforcing layer 20, and the sound absorbing layer 30 absorbs sound energy sufficiently. It is presumed that the sound absorption is not lowered. In order to adjust the air permeability of the reinforcing layer, the weight and thickness per unit area may be adjusted. When the weight per unit area is reduced or the thickness is reduced, the air permeability of the reinforcing layer is increased. Can be made.

  The sound absorbing layer 30 is formed so as to have a breathability by collecting a large number of fibers, and is configured by using fibers processed to have bulkiness as a base material. The fiber used for the sound absorbing layer can be a thermoplastic resin fiber, a fiber in which an additive material such as a filler is added to the thermoplastic resin, other resin fibers, and the like. Polyester fiber, polyamide fiber, acrylic fiber, PP Fibers, PE fibers, glass fibers, carbon fibers, rayon fibers, PET fibers, fibers made of a material added with an additive such as a filler (for example, a blending ratio less than that of resin), and the like can be used. When a fiber having high bulkiness is obtained by applying a high crimping process or needling to the fiber used for the sound absorbing layer, the sound absorbing layer becomes thick, so that a good sound absorbing property can be obtained.

Alternatively, the sound absorbing layer may be formed by using the above-described material fiber as the base material fiber for the sound absorbing layer and adding a thermoplastic fiber for the sound absorbing layer different from the base material fiber. The thermoplastic fiber for the sound absorbing layer may be a fiber of a thermoplastic resin, a fiber in which an additive such as a filler is added to the thermoplastic resin, as in the case of the crosslinking fiber of the reinforcing layer, such as PE or PP. Fibers made of thermoplastic resins such as polyolefins, polyesters and polyamides, fibers made of thermoplastic resins whose melting points are adjusted by modifying these thermoplastic resins, and additives such as fillers (for example, resins) Fibers of a material to which a smaller blending ratio) is added, fibers having a core-sheath structure composed of a core fiber and a sheath fiber with these materials, and the like can be used. The sound-absorbing layer thermoplastic fiber is a fiber having good adhesion to the sound-absorbing layer base fiber, and the sound-absorbing layer base fiber is more It is preferable to use a thermoplastic low-melting-point fiber or medium-melting-point fiber having a low melting point. For example, when a low-melting-point fiber or medium-melting fiber compatible with the sound-absorbing layer base fiber is used, Therefore, the shape of the sound absorbing layer can be improved. When a low-melting fiber or a medium-melting fiber having a melting point substantially the same as or higher than that of the crosslinking fiber of the reinforcing layer 20 (sheath fiber in the case of a crosslinking fiber having a core-sheath structure) is used for the sound-absorbing layer thermoplastic fiber, Adhesiveness with the sound-absorbing layer base fiber is improved, and good shape retention is obtained for the sound-absorbing layer. For the low-melting fiber or medium-melting fiber, it is possible to use a fiber made of a thermoplastic resin whose composition is modified by adjusting PP and modified polyester, acrylic, PE, or the like so as to have a relatively low melting point. it can.
The mixing ratio of the sound-absorbing layer base fiber to the sound-absorbing layer thermoplastic fiber is 40 to 80% by weight of the sound-absorbing layer base fiber and 20 to 60% by weight of the sound-absorbing layer thermoplastic fiber. It is preferable to make the blending ratio of the plastic fibers smaller than the blending ratio of the crosslinking fibers in the reinforcing layer. This is because when the mixing ratio of the thermoplastic fiber for the sound absorbing layer is set to the above lower limit or more, the base fiber for the sound absorbing layer can be sufficiently bonded to each other to impart good shape retention to the sound absorbing layer. This is because when the blending ratio of the plastic fibers is less than or equal to the above upper limit, good air permeability is obtained and good sound absorption performance is obtained.
When a fiber composed of a core fiber and a sheath fiber having a melting point lower than that of the core fiber is used as the crosslinking fiber, the core fiber having a melting point higher than that of the sheath fiber is heated and melted even if the sheath fiber is heated and melted. Since it is difficult, the core-sheath structure cross-linking fibers cross-link the base material fibers to improve the strength of the reinforcing layer and further improve the rigidity of the interior material.

The weight per unit area of the sound absorbing layer is preferably 500 to 1500 g / m ² . This is because if the weight per unit area is not less than the above lower limit, sufficient compressive strength can be obtained during thermoforming and good rigidity can be obtained, and if the weight per unit area is not more than the above upper limit, good air permeability can be obtained. This is because good sound absorption is obtained. The thickness of the sound absorbing layer is preferably 2.0 to 10.0 mm, and more preferably 4.0 to 10.0 mm. This is because when the thickness is set to the lower limit or more, good sound absorption is obtained, and when the thickness is set to the upper limit or less, sufficient compressive strength is obtained during thermoforming, and good rigidity is obtained. The density of the sound absorbing layer is preferably 0.05~0.35g / cm ^3, more preferably 0.10~0.30g / cm ^3.
The sound absorbing layer may be a layer having a general part that sufficiently exhibits a sound absorbing function and a local crushing part such as a bent part. In this case, the crushed part having a smaller area than the general part may be crushed thinner than the general part to be about 0.5 g / cm ³ .
If the air-absorbing layer has a high air permeability of 5 cc / cm ² / sec or more, the sound absorbing property is remarkably improved. This is presumably because sound waves traveling from the passenger compartment to the sound absorbing layer 30 are hardly reflected by the sound absorbing layer 30 and enter the sound absorbing layer to sufficiently absorb sound energy. In order to adjust the air permeability of the sound absorbing layer, it is only necessary to adjust the density and the weight per unit area. When the density of the sound absorbing layer is reduced or the weight per unit area is reduced, the air permeability is increased. Can do.

  The sound insulation layer 40 is a thin layer provided on the outer surface of the vehicle opposite to the vehicle interior side with respect to the sound absorption layer 30 for the purpose of blocking sound traveling from the outside of the vehicle to the vehicle interior, and is a non-breathable thermoplastic. Consists of sheets. The thermoplastic sheet includes a resin sheet obtained by molding a thermoplastic resin into a sheet shape, a resin sheet formed by adding an additive such as a filler to the thermoplastic resin, and PE, PP, polyester, polyamide. A sheet made of a thermoplastic resin such as, a sheet made of a material obtained by adding an additive material (for example, a blending ratio less than that of the resin) to the thermoplastic resin, or the like can be used.

The weight per unit area of the sound insulation layer is preferably 30 to 1000 g / m ² . This is because if the weight per unit area is not less than the above lower limit, the thermoplastic sheet will not break at the drawn portion of the molded product, and if the weight per unit area is not more than the above upper limit, good moldability can be easily obtained. This is because it can be thermoformed into a desired shape. The thickness of the sound insulation layer is preferably 0.03 to 1.0 mm. This is because if the thickness is set to the above lower limit or less, the thermoplastic sheet does not break at the drawn portion of the molded product. If the thickness is set to the upper limit or less, good moldability is obtained during thermoforming, and the desired shape is easily heated. This is because it can be molded.
By stacking the non-breathable thermoplastic sheet, the sound insulation performance of the automobile interior material is improved. At this time, not only the sound insulation performance of only the sound insulation layer 40 but also the effect of improving the sound insulation performance is obtained by the layers including the skin layer 10, the reinforcing layer 20, and the sound absorption layer 30 functioning as the sound insulation layer.

  The backing layer 50 prevents the deterioration of the moldability due to the deformation of the thermoplastic sheet when the thermoplastic sheet constituting the sound insulation layer 40 is heated and brought into the mold, for the purpose of improving the handling property. It is a thin layer provided on the outer surface of the sound insulation layer. The backing layer is preferably a non-woven fabric, and more preferably a low-weight non-woven fabric. Nonwoven fabrics used for the backing layer include nonwoven fabrics made of thermoplastic resin fibers, nonwoven fabrics made of fibers with additives such as fillers added to thermoplastic resins, polyester, polyamide, acrylic, PP, PE, PET, etc. Non-woven fabric made of fibers formed by composing a resin having a relatively high melting point, non-woven fabric made of fibers made of a material obtained by adding an additive such as a filler (for example, a blending ratio less than that of resin) to these resins, Etc. can be used.

Weight per unit area of the backing layer, 15 to 100 / m ² is preferred. This is because when the weight per unit area is equal to or higher than the lower limit, the thermoplastic sheet constituting the sound insulation layer is sufficiently reduced in drawing down, and when the weight per unit area is equal to or lower than the upper limit, the heat is reduced. This is because good moldability is obtained at the time of molding, and it can be easily thermoformed into a desired shape. The thickness of the backing layer is preferably 0.05 to 1.0 mm. This is because when the thickness is equal to or higher than the lower limit, the thermoplastic sheet constituting the sound insulation layer is heated, and the drawdown of the sheet becomes sufficiently small. When the thickness is equal to or lower than the upper limit, good moldability is obtained during thermoforming. This is because it can be easily thermoformed into a desired shape.
By providing a backing layer, when the thermoplastic sheet is brought into the mold in a heated and melted state, the thermoplastic sheet will not sag or deform, greatly improving the handling of the thermoplastic sheet. To do.

(2) Manufacturing method of automotive interior materials:
Next, a method for manufacturing the automobile interior material will be described with reference to FIG.

(2-1) Formation of laminate:
First, the laminated body 60 is formed by heating and melting the thermoplastic fibers constituting the reinforcing layer by at least superposing the sound absorbing layer 30 and the reinforcing layer 20 and heating them by needling. In this embodiment, the thermoplastic fiber existing in the skin layer 10, the reinforcing layer 20, and the sound absorbing layer 30 is heated by supplying hot air by overlapping the skin layer 10, the reinforcing layer 20, and the sound absorbing layer 30, and supplying the hot air. Melt to form a laminate. As a specific example, first, the fibers constituting the skin layer 10, the fibers constituting the reinforcing layer 20, and the fibers constituting the sound absorbing layer 30 are overlapped in this order and subjected to slight needling. , 30 are entangled and integrated. Subsequently, hot air is heated by a suction heater (hot air circulation heater), and the melting point is higher than the melting point of the reinforcing layer cross-linking fiber (or the sheath fiber in the case of a core-sheath structure fiber) and lower than the melting point of the reinforcing layer base fiber. Is preheated to a temperature close to the melting point of the base fiber, and brought into the press mold in a state where the crosslinking fiber (sheath fiber in the case of a fiber having a core-sheath structure) is almost melted. When the sound absorbing layer 30 includes the thermoplastic fiber for the sound absorbing layer, the heating temperature by the hot air is equal to or higher than the melting point of the thermoplastic fiber for the sound absorbing layer and less than the melting point of the base fiber for the sound absorbing layer. The temperature is close to the melting point of the base fiber. When the skin layer 10 contains the thermoplastic fiber for the skin layer, the heating temperature by the hot air is equal to or higher than the melting point of the thermoplastic fiber for the skin layer and less than the melting point of the matrix fiber for the skin layer. The temperature is close to the melting point of the base fiber. Then, the thermoplastic fiber for the sound absorbing layer and the thermoplastic fiber for the skin layer are brought into the press mold in a substantially melted state.
Since each layer 10, 20, and 30 is heated almost uniformly to the inside by hot air heating, there is no uneven forming temperature in each layer 10, 20, and 30, and a laminate 60 with good moldability is formed during thermoforming. be able to.

(2-2) Formation of binder:
Further, the sound insulation layer 40 and the backing layer 50 are overlapped and heated to melt the thermoplastic sheet constituting the sound insulation layer, thereby forming the binder 70 in which the backing layer and the sound insulation layer are bound. In this embodiment, the binder 70 is formed by radiating and heating the sound insulating layer 40 and the backing layer 50. As a specific example, the thermoplastic sheet constituting the sound insulation layer 40 is formed by superposing the thermoplastic sheet constituting the sound insulation layer 40 and the nonwoven fabric constituting the backing layer 50 and performing radiation heating with an infrastructure heater (infrared heater). The sheet is heated to a temperature higher than the melting point of the sheet, the thermoplastic sheet is heated and softened, integrated with the backing layer 50, and brought into a press mold.
Since the layers 40 and 50 can be heated substantially uniformly by radiant heating, the molding temperature is not biased in the layers 40 and 50, and the binder 70 having good moldability can be formed during thermoforming. .

(2-3) Thermoforming:
The press mold is composed of a pair of molds that can move close to and away from each other, and the mold surface has a desired shape that matches the shape of the vehicle compartment SP1 (for example, an indoor standing wall of an automobile). When the heated unmolded material is placed between a pair of molds and the molds are clamped to bring both molds close to each other, the material is press-molded (a type of thermoforming). Thereafter, the press-molded material can be manufactured by separating the two molds and taking out the material from between the two molds.
In the present embodiment, the press-molding is performed by pressing the sound-insulating layer 40 side of the binder 70 and the sound-absorbing layer 30 side of the laminate 60 in a press-molding die having a shape that matches the shape of the passenger compartment. By doing so, the automobile interior material 100 molded according to the shape of the passenger compartment is manufactured. That is, by placing the skin layer 10, the reinforcing layer 20, the sound absorbing layer 30, the sound insulating layer 40, and the backing layer 50 in this order and placing them between a pair of molds, and clamping and press molding Then, the automobile interior material 100 is formed by forming into a shape along the vehicle body panel of the automobile and laminating the layers 10 to 50.

At this time, the cross-linking fibers (sheath fibers in the case of the core-sheath structure fibers) constituting the reinforcing layer 20 are heated and melted by hot air, and are melted in the reinforcing layer while being crushed by mold clamping. It melts and spreads so as to bridge the base material fibers that are not. In addition, the cross-linking fibers in the molten state of the reinforcing layer bridge the fibers constituting the sound absorbing layer 30 (particularly the base material fibers for the sound absorbing layer) and the base material fibers in the reinforcing layer, and the sound absorbing layer 30 and the reinforcing layer 20 Or the fibers constituting the skin layer 10 and the base material fibers in the reinforcing layer are bridged to bond the skin layer 10 and the reinforcing layer 20 together. When the sound-absorbing layer 30 includes the sound-absorbing layer thermoplastic fiber, the sound-absorbing layer thermoplastic fiber is heated and melted by hot air and is melted in the sound-absorbing layer while being crushed by mold clamping. It melts and spreads so as not to bridge the base fiber for the sound absorbing layer. When the outer skin layer 10 includes the outer skin layer thermoplastic fiber, the outer skin layer thermoplastic fiber is heated and melted by hot air and is melted in the outer skin layer while being crushed by clamping. It melts and spreads so that no base material fiber for the skin layer bridges.
The thermoplastic sheet constituting the sound insulation layer 40 is in a molten state by being radiantly heated, and is adhered to the nonwoven fabric constituting the backing layer 50 and is also adhered to the base fiber in the sound absorbing layer by clamping. The backing layer 50 and the sound absorbing layer 30 are bonded together.

When the temperature decreases after press molding, the cross-linking fibers that were in the molten state in the reinforcing layer 20 are solidified again, and the base material fibers in the reinforcing layer are joined together, or the fibers of the sound absorbing layer and the base material fibers of the reinforcing layer Are cross-linked, or the fibers of the skin layer and the base fiber of the reinforcing layer are cross-linked to maintain the press-formed shape. At this time, the reinforcing layer 20 is formed by thermoforming a fiber in which the base material fiber and the crosslinking fiber are blended in accordance with the shape of the passenger compartment, and maintains air permeability between the solidified crosslinking fibers. The base fiber is left and it is a breathable reinforcing layer. The skin layer 10 is formed by thermoforming fibers according to the shape of the passenger compartment, and the fibers that retain air permeability remain between the solidified thermoplastic fibers for the skin layer and the crosslinking fibers of the reinforcing layer. It is formed to have air permeability. The sound-absorbing layer 30 is formed by thermoforming fibers according to the shape of the passenger compartment, and the sound-absorbing layer base material fiber that retains air permeability remains between the solidified thermoplastic fibers for the sound-absorbing layer. , Formed to have air permeability. The sound absorbing layer 30 maintains a desired bulkiness according to the clearance between the molds.
The thermoplastic sheet in a molten state in the sound insulating layer 40 is formed by thermoforming according to the shape of the passenger compartment together with the nonwoven fabric of the backing layer 50, and is solidified again to maintain the press-formed shape.
In the interior material 100, since the laminated body is heated almost uniformly to the inside and the binder is heated almost uniformly by radiation, there is almost no unevenness in the heating temperature in each layer 10 to 50, and the moldability is excellent and good quality. It is formed into interior material.
In addition, since the reinforcing layer contains a large amount of cross-linking fibers, it has a certain rigidity after molding, and also has a role of imparting shape retention in the interior material, and the thermoplastic sheet has a sound absorbing layer. Therefore, the rigidity is further increased by the interaction between the reinforcing layer and the thermoplastic sheet, and it becomes possible to produce a molded product having extremely excellent molding retention.
As described above, a high-quality automobile interior material can be easily manufactured.

(3) Functions and effects of automotive interior materials:
The automobile interior material 100 is a thin skin layer in which a lightweight sound-absorbing layer in which fibers are aggregated is sandwiched between a thin sound insulating layer made of a thermoplastic sheet and a thin reinforcing layer formed of fibers, and is lined with a thin backing layer. Since it is covered and thermoformed, it is lightweight and has good rigidity, and furthermore, good shape retention sufficient to maintain a required shape after molding can be obtained. That is, a certain rigidity can be given by the reinforcing layer, and the effect of further improving the rigidity can be obtained by sandwiching the sound absorbing layer made of fibers between the sound insulating layer made of the thermoplastic sheet and the reinforcing layer. In addition, when the sound insulating layer made of a thermoplastic sheet is heated and melted and brought into the mold, the thermoplastic sheet is not sagted or deformed by the backing layer, so that the handling property of the thermoplastic sheet is remarkably improved. Furthermore, a design property suitable as an interior material is imparted by the skin layer, and an interior material having a good appearance can be provided.

  A road vehicle that travels at high speed on the road generates relatively large road noise and wind noise compared to a vehicle that travels at a relatively low speed. These sounds try to enter the vehicle interior from the outside of the vehicle, but since the sound insulation layer 40 backed by the backing layer is provided on the outside of the interior material 100, the sound insulation layer 40 reflects the sound, and the vehicle interior Intrusion into can be blocked. Furthermore, since the bulky sound absorbing layer 30 is provided on the vehicle interior side of the sound insulating layer, it is possible to more reliably block noise from entering the outside of the vehicle. On the other hand, the reinforcing layer 20 and the skin layer 10 provided on the vehicle interior side of the sound absorbing layer are formed to have air permeability. Therefore, the sound that has entered the passenger compartment is not reflected by the skin layer or the reinforcing layer, but passes through the skin layer 10 or the reinforcing layer 20 and enters the breathable sound absorbing layer 30 as shown by the arrows in FIG. Sound absorption. As a result, it is possible to sufficiently absorb the sound that has entered the vehicle interior while sufficiently preventing the intrusion of sound from outside the vehicle, effectively reducing the noise entering the passenger's ears in the vehicle interior, Can be improved.

(4) Modification:
The present invention can be modified in various ways.
The thermoforming for obtaining an automotive interior material by thermoforming in the state where the above-mentioned layers are laminated may be other than press molding, or in press molding combined with differential pressure molding such as vacuum molding, pressure molding, or vacuum / pressure molding. Good.
Heating when the skin layer, the reinforcing layer, and the sound absorbing layer are stacked and heated to form a laminated body is preferably hot air heating from the viewpoint of heating uniformly, but radiation heating, heating that contacts a heated metal plate , Etc.
Heating when the sound insulating layer and the backing layer are overlapped to form a binder may be radiant heating from the viewpoint of uniform heating, but may be hot air heating, heating to contact a heated metal plate, etc. .

As shown in FIG. 4, it is also possible to manufacture the automobile interior material 101 by thermoforming according to the shape of the passenger compartment in a state where the layers 10 to 40 are laminated without providing the backing layer. For example, if the thermoplastic sheet constituting the sound insulation layer 40 is made to have a thickness that can be suppressed to a certain extent, and the heating temperature is set to a temperature that can be suppressed to a certain extent to prevent a deformation or deformation, the backing layer is changed. Can be omitted. Then, the interior material 101 is formed by press-molding the heated laminate and the heated thermoplastic sheet.
Even in the interior material 101, the sound entering from the outside of the vehicle is reflected by the non-breathable sound insulation layer to block the passage into the vehicle interior, while the sound entering the vehicle interior is blocked by the breathable skin layer and the breathable skin layer. The sound passes through the reinforcing layer and enters the sound absorbing layer to be absorbed. In addition, the lightweight sound-absorbing layer that aggregates the fibers is sandwiched between the lightweight sound-insulating layer made of a thin thermoplastic sheet and the lightweight reinforcing layer formed from the fibers, so it is lightweight but good Further, the shape is rigid, and good shape retention sufficient to maintain a required shape after molding can be obtained.

As shown in FIG. 5, it is also possible to manufacture the automobile interior material 102 by thermoforming according to the shape of the passenger compartment in a state where the layers 20 to 40 are laminated without providing a skin layer. In this case, the reinforcing material 20 and the sound absorbing layer 30 are overlapped and heated to form a laminate, and the laminate and the heated thermoplastic sheet are overlapped and press molded to form the interior material 102. .
Even in the interior material 102 , the sound entering from the outside of the vehicle is reflected by the non-breathable sound insulation layer and blocked from passing into the vehicle interior, while the sound entering the vehicle interior passes through the breathable reinforcement layer. The sound enters the sound absorbing layer and is absorbed. In addition, the lightweight sound-absorbing layer that aggregates the fibers is sandwiched between the lightweight sound-insulating layer made of a thin thermoplastic sheet and the lightweight reinforcing layer formed from the fibers, so it is lightweight but good Further, the shape is rigid, and good shape retention sufficient to maintain a required shape after molding can be obtained.
Of course, an interior material in which a reinforcing layer, a sound absorbing layer, a sound insulating layer, and a backing layer are laminated can be manufactured in the same manner, and the same operation and effect can be obtained.

(5) Example:
EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated concretely, this invention is not limited by an Example.

[Example 1]
The fibers forming the skin layer are PET fibers having a fineness of 6.6 dtex, a fiber length of 51 mm, and a melting point of 260 ° C. as a base fiber, and a PET fiber having a core portion of a melting point of 260 ° C. as a thermoplastic fiber (melt fiber) for the skin layer. And a core-sheath structure fiber having a fineness of 4.4 dtex and a fiber length of 51 mm of a low melting point polyester fiber having a melting point of 110 ° C. was used. The blending ratio of the base material fibers was 92% by weight and the blending ratio of the melt fibers was 8% by weight. Both were mixed almost uniformly to form a skin layer.
The fiber forming the reinforcing layer includes a PET fiber having a fineness of 6.6 dtex, a fiber length of 51 mm and a melting point of 260 ° C. as a base fiber, and a PET fiber having a melting point of 260 ° C. as a cross-linking fiber (melt fiber). A core-sheath structure fiber having a fineness of 4.4 dtex and a fiber length of 51 mm was used. The blending ratio of the base material fiber was 30% by weight, and the blending ratio of the melt fiber was 70% by weight. Both were mixed almost uniformly to form a reinforcing layer.
The fibers forming the sound-absorbing layer are PET fibers having a fineness of 6.6 dtex and a fiber length of 51 mm and a melting point of 260 ° C. as the base fiber, and a fineness of 6.6 dtex and a fiber length of 51 mm and a melting point of 160 ° C. as the thermoplastic fibers for the sound-absorbing layer. PP fiber was used. The blending ratio of the base material fibers was 68% by weight, and the blending ratio of the PP fibers was 32% by weight. The fibers were mixed almost uniformly to form a sound absorbing layer.
A PE sheet having a weight per unit area of 250 g / m ² , a thickness of 0.3 mm, and a melting point of 107 ° C. was used as the thermoplastic sheet constituting the sound insulation layer.

The fibers forming the skin layer were spread and arranged in layers so that the weight per unit area was 150 g / m ² and the thickness after molding was 0.5 mm. The fibers forming the reinforcing layer were arranged in layers on the outer surface of the skin layer so that the weight per unit area was 150 g / m ² and the thickness after molding was 0.5 mm. The fibers forming the sound absorbing layer were arranged in layers so that the weight per unit area was 850 g / m ² and the thickness after molding was 4.5 mm on the outer surface of the reinforcing layer. Then, the skin layer, the reinforcing layer, and the sound absorbing layer were slightly needled in the state of being stacked in this order, and the layers were entangled and integrated. Subsequently, a laminated body was formed by preheating to 220 ° C. with hot air using a hot air circulating heater, and brought into a press mold having a flat plate surface.
Further, the thermoplastic sheet constituting the sound insulation layer was preheated to 170 ° C. by radiant heating using an infrared heater and brought into the press mold. At that time, the sound insulating layer side of the binder and the thermoplastic sheet were overlapped and arranged in a press mold.
Then, the press mold was clamped and pressed for 80 seconds to form a test sample of an interior material having a thickness of 4.0 mm and 0.6 m × 0.6 m by press molding.

[Example 2]
The same fiber as in Example 1 was used as the fiber forming the skin layer, the fiber forming the reinforcing layer, the fiber forming the sound absorbing layer, and the thermoplastic sheet constituting the sound insulating layer.
As the non-woven fabric constituting the backing layer, a non-woven fabric in which the weight per unit area was 70 g / m ² , and the constituting fibers were PET fibers having a fineness of 6.6 dtex, a fiber length of 51 mm, and a melting point of 260 ° C. was used.

The laminate was formed under the same conditions as in Example 1 and was brought into the same press mold as in Example 1.
In addition, the nonwoven fabric constituting the backing layer is superimposed on the thermoplastic sheet constituting the sound insulation layer, and the binder is preheated to 170 ° C. by radiant heating using an infrared heater, and is brought into the press mold. It is. At that time, the sound insulation layer side of the binder and the sound absorption layer side of the laminate were overlapped and placed in the press mold.
Then, the press mold was clamped and pressed for 80 seconds to form a test sample of an interior material having a thickness of 6.0 mm and 0.6 m × 0.6 m by press molding.

[Comparative Example 1]
As shown in FIG. 6, this comparative example is an example of producing an interior material that has been conventionally used mainly as a deck side trim of an automobile, and is generally an interior material that is not provided with a reinforcing layer. It is an example.
The same base material fiber and melt fiber as in Examples 1 and 2 were used for the fibers forming the skin layer 1, and the mixing ratio of the base material fiber and the melt fiber was also the same as in Examples 1 and 2.
A PE sheet having the same weight, thickness, and melting point per unit area as in Examples 1 and 2 was used for the thermoplastic sheet constituting the backing layer (sound insulation layer 2).
As the fibers constituting the rigid layer (damping / sound absorbing layer 3), glass fibers having a fiber diameter of 13 μm and a fiber length of 51 mm, and PP fibers having a fineness of 6.6 dtex, a fiber length of 51 mm, and a melting point of 160 ° C. were used. The blending ratio of the glass fibers was 40% by weight and the blending ratio of the PP fibers was 60% by weight. Both were mixed almost uniformly to form a sound absorbing layer.

For the fibers that form the skin layer, the weight per unit area is 150 g / m ² , and the layers are spread and arranged so that the thickness is 0.5 mm after molding. Needleing is performed, and the fibers are entangled to produce a nonwoven fabric. did. Thereafter, a PE sheet was overlaid on the back side of the skin layer and pre-heated to 170 ° C. by radiant heating using an infrared heater and integrated to form a binder, which was brought into the same press mold as in Example 1. .
Separately from the above, the needling is applied to the mat of glass fiber and PP fiber constituting the rigid layer, the fibers are entangled and integrated, the weight per unit area is 800 g / m ² , and the thickness after molding is 10 mm. A glass fiber / PP fiber substrate was prepared as described above. Subsequently, it was preheated to 220 ° C. with hot air using a hot air circulating heater and brought into the press mold. At that time, the backing layer side of the binder and the glass fiber / PP fiber base material were stacked and placed in a press mold.
Then, the press mold was clamped and pressed for 80 seconds to form a comparative sample of the interior material having a thickness of 4.0 mm and 0.6 m × 0.6 m by press molding.

[Comparative Example 2]
This comparative example is an example of an interior material in which the sound insulation layer is removed from the interior material of Example 1 and only the skin layer, the reinforcing layer, and the sound absorption layer are laminated. Therefore, the same fiber as in Example 1 was used as the fiber forming the skin layer, the fiber forming the reinforcing layer, and the fiber forming the sound absorbing layer.
The laminated body in which the skin layer, the reinforcing layer, and the sound absorbing layer were laminated was formed under the same conditions as in Example 1 and brought into the same press mold as in Example 1.
Then, the press mold was clamped and pressed for 80 seconds to form a comparative sample of the interior material having a thickness of 4.0 mm and 0.6 m × 0.6 m by press molding.

[Sound insulation evaluation method]
Using the test sample of Example 1 and the comparative sample of Comparative Example 1, the transmission loss at 200 Hz to 2.5 kHz when noise was incident from the skin layer side was measured. Transmission loss is determined by combining felt (density 0.055 g / cm ³ , thickness 10 mm) on a panel equivalent to a vehicle (0.8 mm iron plate) and each sample so that the skin layer side is the anechoic chamber side, and noise from the panel side. Was measured by the acoustic intensity method.

[Sound absorption evaluation method]
Using the test samples of Examples 1 and 2 and the comparative sample of Comparative Example 1, the normal incident sound absorption coefficient at 200 Hz to 5 kHz when noise was incident from the skin layer side was measured. The normal incident sound absorption coefficient was measured according to ISO 10534-2 “Acoustics—Measurement of sound absorption coefficient and impedance by impedance tube—” at a 1/3 octave band center frequency (Hz).

[Evaluation results]
The results are shown in FIGS. FIG. 7 is a graph showing measurement results of transmission loss (unit:%) with respect to the center frequency (unit: Hz) for each 1/3 octave band of 200 Hz to 2.5 kHz for Example 1 and Comparative Example 1. . FIG. 8 is a graph showing the measurement results of the normal incident sound absorption coefficient (unit:%) with respect to the center frequency (unit: Hz) for each 1/3 octave band of 200 Hz to 5 kHz for Examples 1 and 2 and Comparative Example 1. ing.
As shown in FIG. 7, the transmission loss value of Example 1 exceeded the transmission loss value of Comparative Example 1, and the difference in transmission loss increased particularly from the middle frequency range to the high frequency range. Since the sound from the outside of the vehicle is further insulated as the transmission loss increases, it was confirmed that the automobile interior material of the present invention has a sound insulation performance superior to that of the conventional interior material.
As shown in FIG. 8, the value of the normal incidence sound absorption coefficient of Example 1 in which the backing layer was not provided exceeded the value of the normal incidence sound absorption coefficient of Comparative Example 1 in a high frequency range of 2.5 kHz or more, and the backing layer was provided. The value of the normal incident sound absorption coefficient of Example 2 exceeded the value of the normal incident sound absorption coefficient of Comparative Example 1 from the middle frequency region to the high frequency region of about 800 Hz or more. The higher the normal incident sound absorption coefficient, the more the sound that has entered the vehicle is absorbed. Particularly, high-frequency sound of about 2 kHz to 4 kHz has a high sensitivity in human approximate auditory characteristics. It was confirmed that automobile interior materials have better sound absorption performance than conventional interior materials.

[Rigidity evaluation method]
The test samples of Examples 1 and 2 and the comparative sample of Comparative Example 2 are each cut into a size of 150 × 50 mm, supported at two points with a distance between the fulcrums of 50 mm, and the center position between the fulcrums at a speed of 50 mm / min. A bending elastic gradient serving as an index of bending rigidity was obtained by measuring the load generated by pressing with a pressing element. The bending test was conducted at a test speed of 50 mm / min and a distance between fulcrums of 50 mm according to JIS K7171 “Plastics—Bending property test method”. The bending elastic gradient was calculated from the bending elastic modulus using the following formula.
(Bending elastic gradient) = [elastic modulus × 4 × sample width 50 mm × sample thickness (mm) ³ ]
/ [Distance between fulcrums 50mm ³ ] × 10

[Evaluation results]
The measurement results of the bending elastic gradient obtained by the above three-point bending test are shown below.
Sample thickness (mm) Bending elastic gradient (N / cm)
Example 1 (no backing layer) 4.0 75
Example 2 (with backing layer) 6.0 85
Comparative Example 2 (no sound insulation layer) 4.0 41
In Comparative Example 2 where no sound insulation layer is provided, the bending elastic gradient is relatively small at 41 N / cm, whereas in Example 1, the bending elastic gradient is 75 N / cm, and in Example 2, the bending elastic gradient is 85 N / cm. It was big. Since the large bending elastic gradient means that the shape retention performance after molding is large, the interior material of the present invention is formed by sandwiching a sound absorbing layer between a breathable reinforcing layer and a non-breathable thermoplastic sheet and laminating. As a result, it was confirmed that the shape retention after molding was remarkably improved.

As described above, according to the present invention, according to various aspects, in an interior material for an automobile having an uneven shape , sound from the outside of the vehicle can be sufficiently prevented and sound that has entered the vehicle interior can be sufficiently absorbed. Thus, it is possible to provide an automotive interior material excellent in shape retention property and capable of maintaining a required shape even after molding, and a manufacturing method thereof.

The front view which shows the principal part of the interior of a road traveling vehicle partially in cross section. The figure which shows the principal part of the interior material for motor vehicles by a vertical cross section. The figure which shows the manufacturing method of the interior material for motor vehicles. The figure which shows the principal part of the interior material for motor vehicles of a modification in a vertical cross section. The figure which shows the principal part of the interior material for motor vehicles of a modification in a vertical cross section. The figure which shows the principal part of the interior material for motor vehicles of a prior art example with a vertical cross section. The figure which shows the measurement result of the transmission loss with respect to the center frequency for every 1/3 octave band. The figure which shows the measurement result of the normal incidence sound absorption coefficient with respect to the center frequency for every 1/3 octave band.

Explanation of symbols

10 ... skin layer,
20 ... reinforcing layer,
30 ... Sound absorbing layer,
40 ... Sound insulation layer,
50 ... backing layer,
60 ... laminate,
70 ... Binder,
100, 101, 102, 108, 109 ... automotive interior materials,
112 ... Door outer panel (a kind of body panel),
114 ... Door inner panel (a kind of body panel),
120 ... floor panel (a kind of body panel),
200 ... a road running car,
SP1 ... Car cabin

Claims (3)

An automotive interior material having an uneven shape laid in a vehicle compartment,
A breathable sound-absorbing layer in which fibers are assembled at a weight per unit area of 500-1500 g / m ² ;
A sound insulating layer made of a non-breathable thermoplastic sheet having a weight per unit area of 30 to 1000 g / m ² and provided on the outer surface of the vehicle opposite to the vehicle compartment side with respect to the sound absorbing layer;
Ventilation formed by assembling 20 to 95% by weight of base material fibers and 5 to 80% by weight of crosslinking fibers, which are thermoplastic fibers, on the surface of the sound absorbing layer on the passenger compartment side. Sex reinforcement layer,
Is obtained by thermoforming in accordance with the shape of an uneven car body panel in a state of being laminated , the sound absorbing layer and the sound insulating layer are in contact, the thickness of the sound absorbing layer is 2.0 to 10.0 mm, and the sound insulating An automotive interior material having an uneven shape , wherein the thickness of the layer is 0.03 to 1.0 mm, and the air permeability of the reinforcing layer is 5 cc / cm ² / sec or more . A backing layer made of a nonwoven fabric having a weight of 15 to 100 g / m ² per unit area is provided on the outside surface of the sound insulation layer, and the backing layer, the sound insulation layer, and the sound absorption layer are sequentially arranged from the vehicle exterior side to the vehicle interior side. The interior material for automobiles having an uneven shape according to claim 1, which is obtained by thermoforming according to the shape of a passenger compartment with at least the reinforcing layer laminated. A method for producing an interior material for an automobile for producing an interior material for an automobile having an uneven shape laid in an automobile compartment,
A breathable sound-absorbing layer in which fibers are aggregated at a weight of 500 to 1500 g / m ² per unit area , 20 to 95% by weight of base fiber and thermoplastic fiber on the surface of the sound-absorbing layer on the passenger compartment side The reinforcing layer is configured by supplying hot air by needling at least a breathable reinforcing layer formed by assembling together 5 to 80% by weight of a crosslinking fiber and thermoforming. Thermoplastic fibers are heated and melted to form a laminate,
A sound insulation layer provided on the exterior of the surface opposite to the vehicle compartment side of the air-impermeable consists thermoplastic sheet the backing layer in which the weight per unit area 30~1000g / m ^2, per unit area A backing layer made of a non-woven fabric having a weight of 15 to 100 g / m ² per layer, and by heating by radiation, the thermoplastic sheet constituting the sound insulation layer is melted to bind the backing layer and the sound insulation layer. Forming a bonded body,
A state in which the sound absorbing layer and the sound insulating layer are in contact with the sound insulating layer side of the binder and the sound absorbing layer side of the laminated body in a mold that is shaped to match the shape of the uneven body panel. by in that by clamping thermoformed superimposed, the thickness of the backing layer is 2.0～10.0Mm, the thickness of the sound insulation layer is 0.03～1.0Mm, air permeability of the reinforcing layer is 5 cc / The manufacturing method of the interior material for motor vehicles which has an uneven shape characterized by manufacturing the interior material for motor vehicles which has an uneven shape which is cm < ² > / sec or more .

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