Method for manufacturing automotive interior material

Abstract

To provide automotive interior material and also to provide a method for manufacturing the automotive interior material, each of which can materialize significant reduction in weight and cost as compared to conventional technologies while ensuring high quality.SOLUTION: An automotive interior material 1 has a thermoplastic film face 10 and a nonwoven fabric face 20 on the opposite side of the film face 10. The film face 10 and the nonwoven fabric face 20 are integrated through a plurality of welding contacts 30 aligned at regular intervals. In a method for manufacturing the automotive interior material, a web is formed by laminating synthetic resin fibers, the web is laminated on the thermoplastic film face 10, and the nonwoven fabric face 20 is formed on the film face 10 by causing the film face 10 and the web to pass through between a pair of heated rolls. At least one of the pair of heated rolls has embossed protrusions aligned at regular intervals on a peripheral surface. In a heated roll step, the film face 10 and the nonwoven fabric face 20 are integrated through the plurality of welding contacts 30 formed by the embossed protrusions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an automobile interior material and a manufacturing method for an automobile interior material, and in particular to an automobile interior material and a manufacturing method for an automobile interior material that can achieve significant weight reduction and cost reduction compared to conventional techniques while ensuring high quality. [Background technology]

[0002] During the automobile manufacturing process, the interior ceiling is installed on the inside of the ceiling material. The interior ceiling consists of an inner layer base material on the ceiling board side and a skin on the passenger compartment side, and the inner layer base material is mainly made of urethane foam (Figures 4 and 5). Automobile ceiling materials are often made from glass fiber, but if the glass fibers fly off, they can prick the skin and cause itching. To prevent the glass fibers from flying off, a sheet called a ceiling lining is placed on the ceiling material side of the inner layer base material to cover the inner surface of the ceiling material. The ceiling lining is made by laminating a plastic film made mainly of polyester, polypropylene, nylon, polyethylene, etc. to one side of a nonwoven fabric made from polyester, rayon, or polypropylene fibers. In detail, it is manufactured by extrusion lamination, which pours molten olefin resin between the nonwoven fabric and the plastic film and presses them together to form an integrated structure. In Patent Document 1, the basis weight is 15 to 40 g / m 2 The present disclosure discloses a thermoplastic film comprising a back layer formed of a nonwoven fabric of about PET and PE fibers, and an air-stop film layer laminated on the lower surface of the back layer, the air-stop film layer being composed of two or three layers of olefin resin films or urethane resin films having a thickness of about 70 to 90 μm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-150005 A [Patent Document 2] JP 2000-318540 A Summary of the Invention [Problem to be solved by the invention]

[0004] The conventional technology has the following problems. <1> The issue of weight reduction In recent years, there has been a push to reduce the weight of automotive parts in order to improve energy efficiency and reduce the environmental impact, and there is also a demand for significant weight reduction in ceiling lining materials. However, in the conventional extrusion lamination method, the material has a three-layer structure consisting of a nonwoven fabric layer, a plastic film layer, and an adhesive layer, and there is a minimum thickness for each layer, so there is a limit to how much the overall weight can be reduced. For example, basis weight (1m 2 Weight per g / m 2 )15g / m 2 ~35g / m 2 Nonwoven fabric of 20μm~30μm (basis weight 18g / m 2 ~27g / m 2 ) plastic film is melted with polypropylene resin (basis weight 13.5g / m 2 ~22.5g / m 2 When glued together, the overall basis weight is 46.5 g / m 2 ~84.5g / m 2 As the polypropylene resin used as an adhesive accounts for approximately 25 to 30% of the total weight, it is difficult to achieve significant weight reduction. <2> Cost Issues The extrusion lamination method consists of three steps: manufacturing the nonwoven fabric, manufacturing the plastic film, and laminating the nonwoven fabric and plastic film together. Since each step requires separate manufacturing and processing equipment, production costs are high. <3> Quality issues Interior ceilings require deep-drawing shapes to improve functionality, such as the ease of deploying side airbags, and design. For this reason, the ceiling lining material must have high quality, including high elasticity and flexibility, so that it can flexibly follow the shape of the formwork when the interior ceiling is molded. However, in the bonding process of the extrusion lamination method, the entire surface of the plastic film comes into contact with an olefin-based resin at 190°C or higher, and in this reheated state, it is pulled (drafted) in one direction for unwinding / winding. As a result, the crystals of the plastic film become oriented in the pulling direction, making the plastic film brittle, reducing its extensibility in the processing direction and making it more susceptible to tearing in the cross direction. Furthermore, the molten olefin resin may get into the spaces between the fibers of the nonwoven fabric, causing the nonwoven fabric to lose its flexibility and thus impair its quality, or the width may be reduced by drafting, reducing its extensibility in the machine direction. <4> Demolding problems Since the nonwoven fabric and plastic film are pressed together in a planar shape, the molten olefin resin may seep through the nonwoven fabric and seep out onto the surface during pressing. In this case, the nonwoven fabric may stick to the mold when released, causing the production line to stop and reducing yields. <5> Equipment issues Equipment that compresses nonwoven fabric and plastic film by sandwiching molten resin between them has complex mechanisms and is expensive, and requires high maintenance costs.

[0005] An object of the present invention is to provide an automobile interior material and a method for producing an automobile interior material in order to solve the above-mentioned problems. [Means for solving the problem]

[0006] The automotive interior material of the present invention is characterized in that it comprises a film surface made of a thermoplastic plastic and a nonwoven fabric surface opposite the film surface, the film surface and the nonwoven fabric surface being integrated via a plurality of welded joints arranged at regular intervals.

[0007] The automotive interior material of the present invention has a basis weight of 30 g / m 2 It may be the following.

[0008] The automobile interior material of the present invention may have a film surface thickness of 40 μm or less.

[0009] The manufacturing method for automotive interior materials of the present invention comprises a web formation process in which synthetic resin fibers are laminated to form a web, a lamination process in which the web is laminated on a film surface made of a thermoplastic plastic, and a heat rolling process in which the film surface and the web are passed between a pair of heat rolls to generate a nonwoven fabric surface on the film surface, characterized in that at least one of the pair of heat rolls has embossed convex portions arranged at regular intervals on its peripheral surface, and in the heat rolling process, the film surface and the nonwoven fabric surface are integrated via a plurality of welding contact points formed by the embossed convex portions.

[0010] In the method for producing an automobile interior material of the present invention, in the web forming step, synthetic resin fibers are laminated on a conveyor by a spunbond method to form a web, and in the laminating step, the web may be transferred from the tip of the conveyor onto a film surface that has been unfolded from a roll form.

[0011] In the method for producing an automobile interior material of the present invention, the basis weight of the nonwoven fabric surface is 30 g / m 2 It may be the following.

[0012] In the method for producing an automobile interior material of the present invention, the thickness of the film surface may be 40 μm or less. Effect of the Invention

[0013] The automobile interior material and the manufacturing method for an automobile interior material of the present invention have at least one of the following effects due to the above-mentioned configuration. <1> Lightweight Compared to the three-layer structure of conventional technology, this product is made up of a two-layer structure consisting of a nonwoven fabric surface and a film surface, eliminating the adhesive layer that accounts for approximately 25 to 30% of the total weight, making it significantly lighter than conventional technology. For example, when the spunbond method is used, the basis weight is 12 g / m 2 Lightweight nonwoven fabric with 20μm (basis weight 18g / m 2 ) polypropylene film, resulting in a basis weight of 30 g / m 2 This makes it possible to manufacture the lightest automotive interior materials available. This is the lightest automotive interior material ever made (grammage 46.5g / m 2 ) this represents a significant weight reduction of over 35%, and contributes to reducing the environmental impact through improved energy efficiency. <2> Low cost The system utilizes nonwoven fabric manufacturing equipment to simultaneously manufacture the nonwoven fabric and press it onto the film surface, meaning that production can be done in two facilities and two processes compared to the three processes required by conventional technology, and since there are no material costs for adhesive, production can be done at low cost. <3> high quality Unlike the conventional extrusion lamination method, there is no need to heat the entire film surface or to strongly stretch the material when sending it out and winding it up after processing. Therefore, there is no risk of losing extensibility or flexibility due to the crystal orientation of the film surface. Furthermore, since no adhesive is used to bond the nonwoven fabric surface and the film surface, there is no risk of the molten adhesive seeping into the nonwoven fabric, allowing the nonwoven fabric to maintain high flexibility. Furthermore, since the nonwoven fabric surface and the film surface are bonded only at the embossed welded contact points rather than over the entire surface, the stretchability and flexibility are extremely high. <4> High releasability Since no adhesive is used, it has high releasability and is less likely to stick to the formwork. <5> Simple facilities It can be manufactured using existing nonwoven fabric manufacturing equipment, and since there is no need for dedicated equipment for lamination, the costs of installing and maintaining the equipment can be reduced. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is an explanatory diagram of an automobile interior material according to the present invention; [Diagram 2] FIG. 1 is an explanatory diagram of a method for producing an automobile interior material according to the present invention; [Diagram 3] Illustration of the heat roll process [Figure 4] Illustration of the prior art [Diagram 5] VV cross section in Figure 4 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an automobile interior material and a method for producing an automobile interior material according to the present invention will be described in detail with reference to the drawings. EXAMPLES

[0016] [Automotive interior materials] <1> Overall configuration (Figure 1) The automobile interior material 1 is a sheet-like ceiling lining material that is disposed between an inner layer substrate and a ceiling material in the interior of an automobile to cover the inner surface of the ceiling material. The automobile interior material 1 comprises a film surface 10 made of a thermoplastic plastic and a nonwoven fabric surface 20 opposite the film surface 10, the film surface 10 and the nonwoven fabric surface 20 being integrated together via a plurality of welded joints 30 arranged at regular intervals. The thicknesses of the film surface 10 and the nonwoven fabric surface 20 can be set arbitrarily. However, in consideration of conformity to an interior ceiling having a deep-drawn shape, the thickness of the film surface 10 is set to 40 μm or less, and the basis weight of the nonwoven fabric surface 20 is set to 30 g / m 2 The following is preferred: The automobile interior material 1 of the present invention has a structure in which the film surface 10 and the nonwoven fabric surface 20 are welded in spots at embossed weld contact points 30 rather than being pressure-bonded over the entire surface, and therefore has extremely high elongation and flexibility. In addition, since there is no molten resin layer acting as an adhesive between the sheets, it is lightweight and has excellent molding freedom, making it ideal as a ceiling lining material.

[0017] <2> Film surface The film surface 10 is the surface of the automobile interior material 1 that mainly exhibits a water-blocking function. The film surface 10 is made of a thermoplastic film. In this example, a polypropylene (PP) film having a thickness of 20 μm is used as the film surface 10. A polypropylene film is suitable as the film surface 10 because it has multiple advantages such as high heat resistance, low specific gravity (lightweight), and high strength. However, the film surface 10 is not limited to a polypropylene film, and may be a polyester (PEs) film, a polyethylene (PE) film, or other olefin-based resin film. The point is that it should have thermoplasticity suited to the manufacturing conditions and physical properties such as elasticity / flexibility that are applicable to the automobile interior material 1.

[0018] <3> Non-woven surface The nonwoven fabric surface 20 is the surface that mainly exhibits the sound insulation and cushioning functions of the automobile interior material 1. The nonwoven fabric surface 20 is formed by hot-rolling a synthetic resin web 21 . In this example, the nonwoven fabric surface 20 has a basis weight of 15 g / m 2 The material used is a nonwoven fabric made of polypropylene fibers. However, the raw material of the nonwoven fabric surface 20 is not limited to polypropylene fibers, but may be polyester (PEs) fibers, polyethylene (PE) fibers, other olefin-based resin fibers, nylon fibers, vinylon fibers, or the like.

[0019] <4> welded contacts The welded joint 30 is the intersection where the film surface 10 and the nonwoven fabric surface 20 are welded to the ceiling. The welded joints 30 are formed in a hot roll step S3 described later by melting and entangling the web 21 in dots at embossing points C1 of the hot roll C and fusing it to the film surface 10 on the back side.

[0020] <5> Manufacturing method for automotive interior materials The manufacturing method of the present invention for automobile interior materials includes at least a web forming step S1, a lamination step S2, and a heat roll step S3. Although the web forming step S1 and the lamination step S2 are described as two separate steps for convenience of explanation, they are actually one step in a series of manufacturing flows. One feature of the method for producing an automobile interior material is that it is possible to produce the automobile interior material 1 without using any lamination / pressing equipment by utilizing a heat roll C of an existing nonwoven fabric production facility. In detail, the automobile interior material 1 can be manufactured, for example, by the following procedure.

[0021] <5.1> Web forming process The web formation step S1 is a step of forming a web 21, which is the material for the nonwoven fabric surface 20. In this example, the web forming step S1 is by a spunbond method. In detail, rice-grain-sized polypropylene pellets are put into extrusion device A, melted, and discharged from a number of nozzle holes with a diameter of 1 mm or less, and stretched by a pulling device while being cooled. In this way, the raw material is fiberized to a diameter of about 30 μm, and is evenly layered on conveyor B to form web 21. The web forming step S1 is not limited to the spunbond method, and any other known method may be used as long as it can continuously form a predetermined amount of the web 21.

[0022] <5.2>Lamination process The lamination step S2 is a step of laminating the web 21 onto the film surface 10. In this example, a rolled film surface 10 is placed below the leading edge (downstream side) of conveyor B, and while the film surface 10 is unfolded, the web 21 is transferred from the leading edge of conveyor B onto the film surface 10. In this example, the web 21 formed in the web forming step S1 is temporarily placed on the conveyor B and then transferred onto the film surface 10, but the web 21 may be laminated directly onto the film surface 10.

[0023] <5.3> Heat roll process (Fig. 3) The hot roll step S3 is a step in which the hot roll C is used to generate the web 21 on the nonwoven fabric surface 20 while simultaneously pressing the film surface 10 and the nonwoven fabric surface 20 together. The heat roll C is a pair of rollers arranged to sandwich the film surface 10 and the web 21 from both sides and feed them in one direction. At least one of the pair of heated rolls C has a mirror surface made of iron and is etched with a plurality of embossed points C1 at regular intervals. In this example, the upper heated roll C of the pair of heated rolls C is provided with the embossed points C1. The heat roll C is preheated to a surface temperature of about 110°C to 150°C. The web 21 laminated on the film surface 10 in the lamination step S2 is passed between heated rolls C together with the film surface 10. As a result, the high-temperature embossing point C1 melts and presses the web 21, entangling the fibers of the web 21 and processing it into a nonwoven fabric surface 20, and at the same time, the nonwoven fabric surface 20 is bonded to the film surface 10 to produce an automobile interior material 1. The manufacturing method for automotive interior materials of the present invention is configured to weld the film surface 10 and the nonwoven fabric surface 20 in a dot pattern at countless welding contact points 30, so there is no need to reheat the entire surface to orient the crystals as in the conventional technology, and there is no risk of a decrease in elongation or increased tearing. In addition, it is possible to control the elongation by selecting the spacing and pattern of the multiple embossing points C1. [Explanation of symbols]

[0024] 1. Automotive interior materials 10 Film surface 20 Non-woven surface 21 Web 30 Welded contacts A Extrusion Device B Conveyor C Heat roll C1 Embossing point S1 Web forming process S2 Lamination process S3 Heat roll process

Claims

1. A film surface made of a thermoplastic plastic; a nonwoven fabric surface opposite the film surface; The film surface and the nonwoven fabric surface are integrated via a plurality of welded contact points arranged at regular intervals. Automotive interior materials.

2. The basis weight of the nonwoven fabric surface is 30 g / m ２ Characterized in that The automobile interior material according to claim 1.

3. The thickness of the film surface is 40 μm or less. The automobile interior material according to claim 1.

4. a web forming step of laminating synthetic resin fibers to form a web; a lamination step of laminating the web onto a film surface made of a thermoplastic plastic; A heat roll process of passing the film surface and the web between a pair of heat rolls to generate a nonwoven fabric surface on the film surface, At least one of the pair of heat rolls has embossed protrusions arranged at regular intervals on a peripheral surface thereof, In the heat roll process, the film surface and the nonwoven fabric surface are integrated via a plurality of welding contacts formed by the embossed convex portions. A manufacturing method for automotive interior materials.

5. In the web forming step, the synthetic resin fibers are laminated on a conveyor by a spunbond method to form the web; In the lamination step, the web is transferred from the tip of the conveyor onto the film surface unfolded from the roll state. The method for producing an automobile interior material according to claim 4.

6. The basis weight of the nonwoven fabric surface is 30 g / m ２ Characterized in that The method for producing an automobile interior material according to claim 4 or 5.

7. The thickness of the film surface is 40 μm or less. The method for producing an automobile interior material according to claim 4 or 5.

Images