JP5764078B2 - Interior materials for vehicles - Google Patents

Description

  The present invention relates to a vehicle interior material formed by laminating three layers composed of a plurality of types of fibers.

  2. Description of the Related Art Conventionally, it has been known that design properties and sound absorption are obtained by installing an interior material made of fibers on a panel constituting a luggage compartment of a vehicle. Since the cargo compartment of a vehicle has a deep uneven shape and an interior material having a shape corresponding to the shape is required, the interior material is required to have excellent drawability. Moreover, it is necessary to comprise in a lightweight. Furthermore, heat-resistant deformation is also necessary so that deformation does not occur even when the vehicle is left under the hot sun for a long time.

  From such a point of view, it is known to use a fiber laminate composed of a plurality of fibers as a vehicle interior material. For example, Patent Document 1 discloses a vehicle made of a three-layer fiber laminate in which polyester fibers (high melting point fibers) and polypropylene fibers (medium melting point fibers) for fusion between the fibers are mixed at a predetermined ratio. An interior material is disclosed. This interior material is a state in which the polypropylene fibers (medium melting point fibers) are partially melted by heating, and the laminated body is formed into a desired shape by press molding so that the polyester fibers (high melting point fibers) have the shape. It is said that it has a function (shape retention) to help solidify.

  However, as a result of investigations by the inventors, the interior material of Patent Document 1 has insufficient rigidity of the vehicle interior material because only the medium melting point fibers that are partially melted between the high melting point fibers are fused.

  Patent Document 2 discloses a trunk floor carpet for an automobile which is made of a fiber laminate including a high softening point polyester staple fiber and a low softening point polyester staple fiber (heat fusion fiber). This floor carpet is said to have improved rigidity because the intersections of the fibers are bonded by heat-bonding fibers, and the fibers are constrained by the bonding points.

  However, as a result of investigations by the inventors, the floor carpet of Patent Document 2 is constrained between the fibers only by the core-sheath type heat-sealing fibers in which the low-melting point copolyester occupies a part of the surface. When placed under a high temperature, the low-melting point copolyester may soften and loosen the restraint between the fibers, and there is a concern about heat resistance.

Japanese Patent No. 2617414 Patent 3610668

  An object of the present invention is to provide a vehicle interior material having high rigidity and excellent heat deformation resistance while maintaining designability (including touch feeling).

The present invention is an interior material for a vehicle that is laid and drawn according to the shape inside the vehicle,
It is composed of three layers, a surface layer, an intermediate layer, and a back layer,
The three layers of the surface layer, the intermediate layer, and the back layer have at least a medium melting point fiber, a high melting point fiber having a higher melting point than the medium melting point fiber, and a resin having a lower melting point than the medium melting point fiber on the surface. Consisting of melting point fiber,
The ratio of the low melting point fiber in the surface layer is 1 to 15% by mass, the ratio of the medium melting point fiber is 15 to 55% by mass, and the ratio of the high melting point fiber is 40 to 80% by mass.
The ratio of the low melting point fiber in the intermediate layer is 10 to 50% by mass, the ratio of the medium melting point fiber is 40 to 75% by mass, and the ratio of the high melting point fiber is 5 to 40% by mass.
The ratio of the low melting point fiber in the back layer is 1 to 15% by mass, the ratio of the medium melting point fiber is 15 to 55% by mass, and the ratio of the high melting point fiber is 40 to 80% by mass.
The resin on the surface of at least a part of the low-melting fiber is melted, and the cross-linking points between the fibers are fused in a dot shape,
An interior material for a vehicle, wherein at least a part of the medium melting point fibers are melted and are fused in a planar shape between other fibers.

  In the present invention, since the resin on the surface of the low-melting fiber is melted and the cross-linking points between the fibers are fused in a dotted manner, the rigidity is improved by the dotted fused portion. In addition, since the medium melting point fibers are melted and fused in a planar shape between the fibers, the heat resistance (particularly, the heat distortion resistance) is improved by the planar fused portion. As a result, it is possible to provide an interior material for a vehicle that has high rigidity and excellent heat deformation resistance while maintaining design properties (including a feeling of touch).

It is typical sectional drawing which shows an example of the fiber laminated body which comprises the vehicle interior material of this invention. It is a cross-sectional photograph which shows an example of the vehicle interior material of this invention. It is a cross-sectional photograph which shows the detail of the melt | fusion part of a fiber. It is a figure which shows the evaluation point of the heat test in an Example.

  FIG. 1 is a schematic cross-sectional view showing an example of a fiber laminate constituting the vehicle interior material of the present invention. This fiber laminate has a configuration in which three layers of a surface layer 1, an intermediate layer 2, and a back layer 3 are laminated in this order. Since each layer 1 to 3 is substantially composed of only fibers, it is easy to adjust the blending, and it is suitable for deep drawing, and is lightweight and has excellent sound absorbing properties. In addition, since it has a sandwich structure in which the intermediate layer 2 is sandwiched between the surface layer 1 and the back layer 3 excellent in heat deformability, warping during heating hardly occurs.

  The three layers of the surface layer 1, the intermediate layer 2 and the back layer 3 are low melting point fibers having at least a medium melting point fiber, a high melting point fiber having a higher melting point than the medium melting point fiber, and a resin having a lower melting point than the middle melting point fiber. It consists of. These three kinds of fibers are blended at a specific ratio to form each layer 1 to 3, and the fiber laminate is heated and drawn to form each fiber. The interior material which has is obtained. Specifically, the high melting point fiber functions as an essential component (basic fiber), the medium melting point fiber functions for planar fusion between other fibers, and the low melting point fiber is a cross-link between the fibers. It works for you.

  FIG. 2 is a cross-sectional photograph (50 ×) showing an example of the vehicle interior material of the present invention. The intermediate layer 2 has a higher proportion of the melted component (low melting point fiber, medium melting point fiber) than the surface layer 1 and the back layer 3, so that after the preheating and drawing, the fibers are closely packed with the melted component, The density is high and the layer is hard. On the other hand, the surface layer 1 and the back layer 3 have a low ratio of melt components (low-melting fiber, medium-melting fiber), so that a lot of voids remain between the fibers, the density is low, and the design texture is good. .

The vehicle interior material has an appropriate air permeability as the entire fiber laminate. Since the air permeability affects the sound absorption performance of the interior material, it may be adjusted according to the requirements of the vehicle on which the interior material is laid. The laminate composed of only fibers can easily adjust the air permeability by changing the fiber diameter and the degree of integration. The air permeability is usually preferably from 70 to 120 cm ³ / cm ² / sec. This air permeability is a value measured according to JIS L1096.

Surface 1, the mass per unit area of the intermediate layer 2 and the back layer 3 (basis weight), respectively ^{50~300g / m 2, 300~900g / m} 2, 30~300g / m 2 is preferred. The total unit area mass of the surface layer 1 and the back layer 3 is preferably 30 to 90% of the unit area mass of the intermediate layer 2. Further, from the viewpoint of suppressing warpage caused by thermal deformation, the difference 0 in unit area mass between the surface layer 1 and the back layer 3 is preferably within ± 50 g / m ² .

  The thicknesses of the surface layer 1, the intermediate layer 2, and the back layer 3 are preferably 0.3 to 1.2 mm, 1.2 to 6.4 mm, and 0.3 to 1.2 mm, respectively. Thus, in the sandwich structure in which the surface layer 1 and the back layer 3 are thinner than the intermediate layer 2, the rigidity of the entire fiber laminate can be improved by increasing the ratio of the high melting point fibers in the surface layer 1 and the back layer 3.

  Hereinafter, three kinds of fibers constituting each of layers 1 to 3 will be described.

<Medium melting point fiber>
The medium melting point fiber has a function of melting when the fiber laminate is preheated or drawn, and fusing other fibers in a planar shape. Specifically, the medium melting point fiber is melted by preheating (about 200 ° C.) or the like at the time of forming the fiber laminate, spreads in a planar shape by the pressure at the time of drawing, and other adjacent fibers (high melting point fiber or It becomes a binder that fuses the cores in the case where the low melting point fibers are core-sheath fibers. Thereby, the heat-resistant deformation property and rigidity of a vehicle interior material can be improved.

  As the medium melting point fiber, for example, a fiber that does not soften even at a general heat resistance test temperature of 80 to 90 ° C. is used. In particular, the softening point of the medium melting point fiber is preferably 140 to 160 ° C, more preferably 145 to 155 ° C. Moreover, 150-180 degreeC is preferable and melting | fusing point has more preferable 155-165 degreeC.

  Specific examples of the medium melting point fiber include polypropylene resin fibers (melting point: 160 to 165 ° C.). The fiber diameter is preferably about 3 to 12 dtex, and the average fiber length is preferably about 30 to 120 mm. Since the polypropylene resin fiber is a lightweight fiber, the effect of weight reduction can be obtained. However, fibers other than polypropylene resin fibers can be suitably used as long as they have similar melting points and fiber diameters.

<High melting point fiber>
The high melting point fiber is a fiber having a higher melting point than the medium melting point fiber. It does not melt at the time of preheating or drawing at the time of forming the fiber laminate, and plays the role of the basic fiber constituting the interior material. The melting point of the high melting point fiber is preferably 235 to 265 ° C, and more preferably 240 to 260 ° C.

  As the high melting point fiber, various kinds of fibers that are conventionally known to be usable for use in vehicle interior materials can be used. Specific examples thereof include polyethylene terephthalate resin fibers (melting point: 255 to 260 ° C.). The fiber diameter of the high melting point fiber is preferably about 1 to 10 dtex, and the average fiber length is preferably about 30 to 120 mm. However, even fibers other than polyethylene terephthalate resin fibers can be suitably used as long as they have similar melting points and fiber diameters.

<Low melting point fiber>
The low melting point fiber is a fiber having a resin (low melting point resin) having a melting point lower than that of the medium melting point fiber at least on the surface. The resin on the surface of the low-melting fiber has a function of melting at the time of preliminary heating or drawing of the fiber laminate and fusing the cross-linking points between the fibers in a dot shape. Specifically, the low melting point resin on the surface of the low melting point fiber is melted by preheating (about 200 ° C.) at the time of forming the fiber laminate, and adjacent fibers (high melting point fibers or low melting point fibers are core-sheath fibers). In this case, it becomes a binder that crosslinks and fuses the cores in the case of dots. Thereby, for example, the low melting point resin fuses the entanglement point between the low melting point fiber and the high melting point fiber entangled by the needle punch in a dot shape. And rigidity can be improved by the point-like fusion location of this low melting point fiber.

  As the low melting point fiber, for example, a conjugate structure fiber having a core-sheath structure or a side-by-side structure can be used. Among these, a core-sheath fiber having a high melting point fiber (particularly the same type of fiber as the high melting point fiber used in combination) and a low melting point resin in the form of a sheath is preferable. When such a core-sheath structure fiber is used, the core part does not melt, but can play the role of a basic fiber constituting the interior material together with the high melting point fiber.

For example, polyethylene terephthalate fiber, polybutylene terephthalate fiber, or polyethylene naphthalate fiber can be used as the core of the core-sheath fiber. The preferable range of the melting point of the core is the same as that of the high melting point fiber described above. In particular, polyethylene terephthalate resin fibers are preferable from the viewpoint of availability and melting point. As the low melting point resin for the sheath, for example, a polyester heat-fusible resin having a melting point lowered by copolymerizing a monomer such as isophthalic acid with polyethylene terephthalate can be suitably used. The softening point of the low melting point resin is preferably 80 to 100 ° C, and the melting point is preferably 100 to 120 ° C.
The fiber diameter of the low melting point fiber is preferably about 1 to 10 dtex, and the average fiber length is preferably about 30 to 120 mm.

<Difference in the action of medium melting point fibers and low melting point fibers>
The medium melting point fiber is an all-melting type fiber, and melts and fuses in a plane between other fibers, so that it largely contributes to the improvement of heat resistance (particularly heat distortion resistance). On the other hand, the low melting point fiber largely contributes to the improvement of rigidity because the low melting point resin on the surface is melted and the cross-linking points of the fibers are fused in a dot shape.

  Comparing both fibers from the viewpoint of heat resistance, the medium melting point fibers have heat resistance that does not cause softening even at the heat resistance test temperature (80 to 90 ° C.) of the vehicle interior material as described above. Moreover, since the fibers are fused in a planar shape, the heat distortion resistance can be improved also by suppressing the deviation between the fibers. On the other hand, when the melting point and softening point of the low melting point fiber are in the range of, for example, around 110 ° C., some softening occurs at the heat resistance test temperature (80 to 90 ° C.) of the vehicle interior material. In addition, since the fibers are merely fused in the form of dots, it is more disadvantageous than the medium melting point fibers in terms of suppressing the shift between the fibers.

  Comparing both fibers from the viewpoint of rigidity, the low melting point fibers fused in a spot shape contribute more greatly to the rigidity than the medium melting point fibers fused in a planar shape.

  Although the preferred ratio differs depending on each layer, for the medium melting point fiber, the ratio in the layer is relatively high so that the sheet can be sufficiently fused in a plane, and for the low melting point fiber, the ratio in the layer is If it is too high, the heat resistance will decrease, so a relatively low ratio is preferable.

  FIGS. 3A to 3C are cross-sectional photographs showing details of the fused portion of the fiber. Here, it can be seen that a point-like fused portion where the fibers are connected in a dot-like manner and a surface fused portion where the fibers are connected in a planar shape are mixed.

  The point fusion part is a resin melted on the surface of the low melting point fiber. For example, the entanglement point between the core parts of the low melting point fiber or the entanglement point of the core part of the low melting point fiber and the high melting point fiber is caused by the resin. It is the fused part. On the other hand, the planar fused portion is a lump portion in which the melted fibers spread in a planar shape by the pressure at the time of drawing without melting the middle melting point fiber and retaining its fiber shape. Since high melting point fibers and low melting point fibers are also present in this planar lump portion, adjacent high melting point fibers, adjacent low melting point fiber cores, or adjacent high melting point fibers and low melting point fiber cores The part is fused with the planar lump portion as a binder. The point-like fused portion mainly contributes to improvement in rigidity, and the planar fused portion mainly contributes to heat resistance (particularly heat-resistant deformation), and as a result, both rigidity and heat resistance can be improved in a well-balanced manner.

<Ratio of each fiber>
The ratio of the low melting point fiber in the surface layer and the back layer is 1 to 15% by mass, the ratio of the medium melting point fiber is 15 to 55% by mass, and the ratio of the high melting point fiber is 40 to 80% by mass. Thus, the design and the feeling of touch can be improved by relatively increasing the proportion of the high melting point fiber, and the rigidity and heat resistance can be balanced by using the low melting point fiber and the medium melting point fiber together.

  If the ratio of the low melting point fibers in the surface layer and the back layer is lower than the above range, the rigidity is lowered, and if it exceeds the above range, the heat resistance is deteriorated. In addition, when not using a low melting point fiber, the problem that a surface fiber tends to come out also arises. In addition, if the ratio of the high melting point fiber is lower than the above range, the ratio of the low melting point fiber and the medium melting point fiber becomes relatively high, and melts at the time of molding, and the non-fiber form progresses. .

  The ratio of the low melting point fiber in the intermediate layer is 10 to 50% by mass, the ratio of the medium melting point fiber is 40 to 75% by mass, and the ratio of the high melting point fiber is 5 to 40% by mass. Thus, if the ratio of the low melting point fiber is made higher than that of the surface layer or the back layer to increase the rigidity, the shape retaining function of the entire interior material can be assumed. That is, in the sandwich structure composed of three layers, the surface layer and the back layer mainly play a role of improving the heat deformation resistance, and the intermediate layer can play a role of improving the shape retention by high rigidity. If the ratio of the low melting point fiber in the intermediate layer is lower than the above range, the rigidity is lowered, and if it exceeds the above range, the heat resistance is deteriorated.

<Method for manufacturing vehicle interior material>
As a method for obtaining a fiber laminate by laminating and integrating three layers, for example, a high melting point fiber, a medium melting point fiber, and a low melting point fiber are mixed at a predetermined ratio, respectively, and three types of webs (surface layer, intermediate layer, back layer) are mixed. ), And laminated in the order of the surface layer, the intermediate layer, and the back layer, and integrated by needle punching. There is also a method in which each layer is preliminarily lightly needle-punched, and then the three layers are stacked and finished to perform needle punching and laminated and integrated.

  As a method for molding a fiber laminate to obtain an interior material for a vehicle, for example, a method of preheating the fiber laminate and placing it in a press mold of a male and female pair and drawing it into a desired shape There is. This method may be performed at a temperature at which the medium melting point fiber and the low melting point fiber are melted and at a temperature at which the high melting point fiber is not melted. By such drawing, a vehicle interior material having a shape that matches the interior shape of the vehicle (for example, the shape of a vehicle luggage compartment panel) can be obtained, and the vehicle interior material can be laid on the panel or the like.

  Hereinafter, the present invention will be described in more detail with reference to examples.

<Examples 1-7, Comparative Examples 1-10>
Polyethylene terephthalate resin fiber (melting point 255-260 ° C., average fiber length 51 mm, fiber diameter 3.3 dtex) as high melting point fiber, polypropylene resin fiber (melting point 160-165 ° C., average fiber length 64 mm, fiber) as medium melting point fiber Diameter 6.6 decitex), core-sheath fiber (average fiber length 51 mm, fiber diameter) of polyethylene terephthalate resin (melting point 255 to 265 ° C.) as core and polyester copolymer (melting point 110 ° C.) as the low-melting fiber. 4.4 dtex) was prepared.

Each fiber is blended and blended for the surface layer, intermediate layer, and back layer at the ratios shown in Table 1 and Table 2, and then the fibers of each layer are entangled by needling, and three layers are stacked, and light needling Was performed so that the fibers of each layer were entangled so that the three layers were not separated from each other to obtain an original fabric (a fiber laminate having a three-layer structure). Mass per unit area of the raw of each layer (basis weight), the surface layer 150 g / m ^2, the intermediate layer is 425 g / m ^2, the backing layer is 125 g / m ^2, the entire fiber laminate was 700 g / m ^2.

  This raw fabric was preheated by ventilation at 200 ° C. for 60 seconds, clamped between a male and female press molding die (cold die), and drawn to a thickness of 1.5 mm. Thereafter, the molded shape is fixed by natural cooling, and the shape corresponding to the side wall of a typical automobile luggage compartment [the shape shown in FIG. A vehicle interior material having a development rate (surface area along the plane / projected area) of 1.50] was obtained.

  The following evaluation was performed about the interior material for vehicles obtained by the Example and the comparative example.

[Creativity]
The design properties were evaluated according to the following criteria based on the visual appearance and feel.
“◯”: The appearance and texture of the fiber are maintained, and there is no rough feeling due to the molten fiber when touched by hand.
“Δ”: The appearance and texture of the fiber are maintained, but there are missing fibers.
“X”: The melted component of the fiber is conspicuous, and there is a rough feeling due to the melted fiber when touched by hand.

[Bending elastic gradient (strength to bending)]
The interior material was cut into a 50 mm × 150 mm strip to obtain a plurality of test pieces. Here, each of a test piece in which the web feed direction (longitudinal direction) when the fiber laminate is laminated becomes the longitudinal direction and a test piece whose width direction (lateral direction) becomes the longitudinal direction were prepared. This test piece is placed so as to be bridged between support pieces having a span of 50 mm, a load is applied at a speed of 50 mm / min from the upper center, and the maximum bending elastic gradient until deformation of up to 2.5 mm (N / 50 mm / cm). ) And the bending elastic gradient (strength against bending) was evaluated according to the following criteria.
“◎”: Bending elastic gradient is 9.0 (N / 50 mm / cm) or more. Within this range, the interior material has sufficient rigidity.
“Δ”: The bending elastic gradient is less than 9.0 (N / 50 mm / cm) and 6.0 (N / 50 mm / cm) or more. If it is within this range, the requirement for rigidity as an interior material is satisfied.
“X”: The bending elastic gradient is less than 6.0 (N / 50 mm / cm). Within this range, the rigidity as an interior material is insufficient, and it is easy to cause blinking and deflection.

[Heat resistance]
The interior material molded in the shape shown in FIG. 4 is fixed to a predetermined member at five locations in the same manner as in an actual vehicle (the circles in the figure are fixed points) and used for a heat resistance test at 80 ° C. for 400 hours. did. The amount of deformation of the interior material after the test was measured at 13 locations on the periphery of the interior material (1 to 13 in the figure are measurement points), the sum of the absolute values was determined, and the heat distortion resistance was evaluated according to the following criteria.
“◯”: The average sum of deformation amounts is less than 15 mm. This range is a value superior to conventional interior materials.
“×”: The average of the total deformation amount is 15 mm or more. This range is equal to or less than that of conventional interior materials.

[Comprehensive judgment]
If all items of designability, rigidity, and heat distortion resistance are ◎ or ○, the overall judgment is ○ (suitable for interior materials for vehicles), and if any of the evaluation items has △ or less, it is comprehensive Judgment was made x (unsuitable as an interior material for a vehicle).

[Evaluation results]
As shown in Table 1, each example was excellent in all the characteristics of design, bending elasticity (gradient), and heat distortion resistance.

  On the other hand, as shown in Table 2, Comparative Example 1 was inferior in design and bending elasticity (gradient) because no low melting point fiber was used for the surface layer and the back layer. Since the ratio of the low melting point fiber of the surface layer and the back layer was too high, the comparative example 2 was inferior in design property and heat-resistant deformation. Since the ratio of the high melting point fiber of the surface layer and the back layer was too low, the comparative example 3 was inferior in design property and heat-resistant deformation. In Comparative Example 4, the ratio of the middle melting point fibers of the surface layer and the back layer was too low, so the heat distortion resistance was inferior. In Comparative Example 5, the ratio of the middle melting point fibers of the surface layer and the back layer was too high, and the ratio of the high melting point fibers was too low, so the design properties were inferior. Since the ratio of the high melting point fiber of the surface layer and the back layer was too high, the comparative example 6 was inferior in design property, bending elasticity (gradient), and heat deformation property.

  Moreover, since the ratio of the low melting-point fiber of the intermediate layer was too low, the comparative example 7 was inferior in heat distortion property. In Comparative Example 8, the ratio of the low-melting fiber in the intermediate layer was too high, and the high-melting fiber was not used. Comparative Example 9 was inferior in heat resistance deformation because the proportion of the middle melting point fibers in the intermediate layer was too low and the proportion of the high melting point fibers was too high. Comparative Example 10 was inferior in heat-resistant deformation because the proportion of the middle-melting fiber in the intermediate layer was too high.

  Since the interior material of the present invention is excellent in design, rigidity, and heat distortion resistance, it can be widely used as an interior material for various vehicles. For example, it is an interior material laid on a surface having a deep concavo-convex shape, such as a floor carpet laid on a panel (trunk floor) of a car bed, and is particularly useful for applications that require designability and heat distortion resistance. .

Claims (2)

It is an interior material for a vehicle that is laid down and drawn in accordance with the shape inside the vehicle,
It is composed of three layers, a surface layer, an intermediate layer, and a back layer,
The three layers of the surface layer, the intermediate layer, and the back layer have at least a medium melting point fiber, a high melting point fiber having a higher melting point than the medium melting point fiber, and a resin having a lower melting point than the medium melting point fiber on the surface. Consisting of melting point fiber,
The ratio of the low melting point fiber in the surface layer is 1 to 15% by mass, the ratio of the medium melting point fiber is 15 to 55% by mass, and the ratio of the high melting point fiber is 40 to 80% by mass.
The ratio of the low melting point fiber in the intermediate layer is 10 to 50% by mass, the ratio of the medium melting point fiber is 40 to 75% by mass, and the ratio of the high melting point fiber is 5 to 40% by mass.
The ratio of the low melting point fiber in the back layer is 1 to 15% by mass, the ratio of the medium melting point fiber is 15 to 55% by mass, and the ratio of the high melting point fiber is 40 to 80% by mass.
The resin on the surface of at least a part of the low-melting fiber is melted, and the cross-linking points between the fibers are fused in a dot shape,
An interior material for a vehicle, wherein at least a part of the medium melting point fibers are melted and are fused in a plane between other fibers.   The vehicle interior material according to claim 1, wherein the low-melting fiber is a core-sheath structure fiber having a fiber having the same kind as that of the high-melting fiber as a core and a resin having a lower melting point than the medium-melting fiber in a sheath shape on the surface.