KR100446901B1 - Interior material for car - Google Patents

Abstract

The present invention relates to a vehicle interior material, polypropylene: a skin layer in which polyester is mixed in a ratio of 8.5 to 7: 1.5 to 3, polypropylene: a middle layer mixed in a ratio of hemp fiber 5: 5, polypropylene: It is characterized in that the polyester consists of a back layer mixed in a ratio of 3.5 to 2: 6.5 to 8.

Automotive interior materials of the present invention is excellent in strength, moldability, heat resistance, impact resistance, environmentally friendly, sound absorption and sound insulation.

Description

Interior material for car}

The present invention relates to interior materials for automobiles.

Automotive interior materials are used in door trims, engine hoods, head linings, shelf backs, fillers, sound insulation, and the like. The door trim is attached to the inner side of the door to improve passenger safety and aesthetics, and the engine hood blocks noise and vibration from the engine compartment to reduce noise and vibration transmitted to the interior and exterior of the vehicle. The headlining also blocks insulation from the outside and noise and vibration from the outside, and the self-bag is mounted on the rear of the rear seat of the car for decorative and multifunctional use.

BACKGROUND ART Conventional automotive interior materials generally have a resin felt or wood fiber, wood stock in a mat state and a skin material formed inside and outside with a nonwoven fabric or the like.

In the process of making such a product, a resin felt or the like is first formed into a mat state, and then inserted between a hot press mold upper mold and a lower mold, pressurized to complete molding. Molded products are produced using a punched (or trim pierced) mold upper and lower molds to produce padded products. In order to attach the skin material such as non-woven fabric to the pad-like product, spray the bond in a spray state, dry it, and complete the vacuum suction molding in an oven or a heater. . In this case, a bond containing toxic chemicals such as toluene is used as a particle spray to adhere the skin to the pad, which is harmful to the operator.

In addition, resin felt and wood fiber use a phenol resin as a binder as a thermosetting resin, so they emit toxic gases during thermoforming, which is not only harmful to the human body but also causes environmental pollution. In particular, resin felt uses a chemical fiber and a phenol resin containing dyes, so when color is melted and cured, formaldehyde is a colorless toxic gas which is highly irritating.

In recent years, automotive interior materials are generally made of a multilayer structure. BACKGROUND ART Automobile interior materials having a multi-layer structure are known in various forms. Among them, polyurethane is used as an intermediate layer, and polyester is generally used by bonding to both sides of the intermediate layer using an adhesive.

Since the interior materials for automobiles of such a multi-layered structure cannot be recycled once bonded, the intermediate layer is used by bonding a sawdust, wood chips, etc., which are natural materials, with adhesive or resin.

U.S. Patent No. 5,709,925, Korean Patent Application Nos. 1998-13416 and 1998-13417 have a three-layer structure consisting of an intermediate mat layer of polypropylene and hemp fibers, and a skin layer of both polypropylene and polyester. Interior materials for automobiles are described. However, the above technology could increase sound absorption and shock absorption, but did not solve the problem of sound insulation.

An object of the present invention is to solve the above problems, and to provide an interior material for automobiles having strength, moldability, heat resistance, impact resistance, environmental friendliness, and sound absorption and sound insulation.

1 is a cross-sectional view of a vehicle interior according to a preferred embodiment of the present invention.

2 is a view showing a manufacturing process of the interior material for automobiles of the present invention.

<Explanation of symbols for the main parts of the drawings>

1: skin layer 2: intermediate layer

3: back layer

The present invention provides a vehicle interior material consisting of a skin layer, an intermediate layer and a back layer.

The automotive interior material of the present invention comprises a skin layer and a back layer, in which a polypropylene: polyester is mixed in a constant ratio, and an intermediate layer in which polypropylene: horse fiber is mixed in a constant ratio. In the skin layer and the back layer, the blending ratio of polypropylene and polyester is different.

The interior material for automobiles of the present invention is a skin layer in which polypropylene: polyester is mixed in a ratio of 8.5-7: 1.5-3, polypropylene: hemp fibers in an intermediate layer mixed in a ratio of 5: 5, polypropylene: polyester is It consists of the back layer mixed in the ratio of 3.5-2: 6.5-8.

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

The automotive interior material of the present invention has a three-layer structure consisting of a skin layer (1), an intermediate layer (2) and a back layer (3).

The intermediate layer 2 is prepared by mixing polypropylene and hemp fibers in a constant mixing ratio. Hemp fiber is a natural fiber that increases the strength and impact resistance of interior materials, and is environmentally friendly because it is inexpensive and fully recyclable. Hemp fibers may be flax, hemp, jute or the like, flax is most preferred. Polypropylene is thermoplastic and imparts moldability to interior materials, and partially melts during lamination to increase cohesion between fibers. Therefore, when the ratio of hemp fibers decreases, the strength falls, and when the ratio of polypropylene decreases, problems in formability occur. Therefore, it is preferable that the mixing ratio of hemp fiber and polypropylene is 5: 5.

The skin layer 1 is prepared by mixing polypropylene and polyester in a ratio of 8.5 to 7: 1.5 to 3, with an 8: 2 ratio being most preferred. Thermoplastic materials, such as polypropylene and polyester, partially dissolve between the intermediate layers during preheating and pressure and act as adhesives without the need for conventional bonding in the bonding with the intermediate layer 2. The polyester remains in the skin layer (1) area to block the air and moisture to prevent damage to the natural fibers in the intermediate layer by moisture, as well as maximize the sound insulation effect.

The back layer 3 is produced by mixing polypropylene and polyester in a ratio of 3.5 to 2: 6.5 to 8, with a 3: 7 ratio being most preferred. When mixed in this ratio, the sound absorption effect is maximized.

The manufacturing process of the automotive interior material of the present invention is 1) adding the raw material, 2) mixing each raw material, 3) making a surface, 4) layering, 5) compacting, 6) forming a single layer And 7) bonding the skin layer, the intermediate layer, the back layer, and 8) the cutting step (FIG. 2).

Looking at the manufacturing process of the intermediate layer (2) is as follows.

Weigh the polypropylene and flax and feed it into the hopper by the automatic feeder, then move to the mixing feed through the scoop and mix well. When polypropylene and flax are completely mixed, they are transferred to the carder through the feeder. The front part of the carding machine is roll type, and when the material mixed with the card is passed, a thin surface is formed. The formed surface is moved to a molding machine and stacked in layers by a desired thickness. The surface formed of several layers is moved with a needle and chopped with 20,000 to 30,000 needles. Move the chopped side to the cutter and roll it up to the desired length. The intermediate layer 2 thus produced is returned to the molding machine and hanged on the product hanger.

Skin layer (1) is produced in the same process to the carding machine of the intermediate layer (2) manufacturing process by measuring the weight of polypropylene and polyester by an automatic transfer device. The surface formed in the card machine is moved to the molding machine and placed on the intermediate layer (2) hanging on the product hanger. The surface on which the skin layer 1 and the intermediate layer 2 are bonded is moved to a needle and a cutting machine, and rolled to a desired length to form a mat having a two-layer structure to which the skin layer 1 and the intermediate layer 2 are bonded.

The back layer 3 is manufactured by measuring the weight of polypropylene and polyester in the same process as the manufacturing process of the intermediate layer 2 by an automatic transfer device.

The roll and the back layer (3) to which the skin layer (1) and the middle layer (2) are bonded are transferred to a heater, and the roll on which the skin layer (1) and the middle layer (2) are bonded is placed on the top, and the back layer ( 3) Hang the roll on the bottom and apply heat and pressure to turn it inward to form a three-layer mat.

Attaching a nonwoven fabric made of polyester to the back layer 3 of the three-layer structure mat can further improve the sound absorbing effect.

When manufacturing the interior materials, the skin layer, the middle layer and the back layer is adjusted to 2400 ~ 1200g / ㎡ by adjusting the density as needed, according to the applied area the heaviest one for the door trim, self bag Lightweight, such as 1200g / ㎡ is to be applied.

Since the material of the automotive interior material according to the present invention is a thermoplastic resin, if necessary, various accessories, such as a retainer, a bracket, or a channel, to be mounted on the interior material, may be simultaneously heat-molded.

In addition, since materials such as polypropylene and polyester used in the skin layer and the back layer of the automotive interior material according to the present invention are thermoplastic, they can be bonded only by preheating and pressure without the conventional bonding in the bonding with the intermediate layer. Do.

Hereinafter, the present invention will be described in more detail with reference to the following examples, which are intended to illustrate the present invention but are not intended to limit the scope of the present invention.

Example

The intermediate layer is polypropylene and flax 5: 5, the skin layer is polypropylene and polyester 8: 2, and the back layer is polypropylene and polyester in a ratio of 3: 7 according to the production method disclosed in the above description. A three layer structure layer was prepared.

The working conditions were 185 ± 10 ℃ for the upper mold temperature and 120 ± 20 ℃ for the lower mold temperature of the preheating plate.

The thickness of the finished product was 2.5-25T.

Physical properties were tested to determine the sound absorbing and sound insulating power of the interior material for automobiles according to the present invention.

The test material was a mat consisting of the three-layer structure mat and resin felt prepared above.

The test method was carried out according to the KSF 2814078, ASTM C384-90a method.

Both materials are 2.5T thick, 100mm at low frequencies (125-1000 Hz) and 30mm at high frequencies (1.0-4.0k).

Sound absorbing force measurement results are shown in Table 1.

Frequency 250 315 400 500 630 800 1000 1,250 1,600 Example (dB) of the present invention 0.14 0.19 0.15 0.07 0.11 0.21 0.24 0.32 0.31 Resin felt (dB) 0.02 0.09 0.06 0.08 0.09 0.10 0.14 0.21 0.10

As shown in Table 1, it can be seen that the interior material of the present invention toward the higher frequency is more excellent sound absorption effect than the mat using a conventional resin felt.

The measurement result of the sound insulation is shown in Table 2.

Frequency 250 315 400 500 630 800 1,000 1,250 1,600 2,000 2,500 Example (dB) of the present invention 72.0 68.2 64.8 62.6 57.9 50.7 55.4 59.1 61.8 72.9 74.9 Resin felt (dB) 55.2 52.0 48.9 46.2 37.3 26.3 47.6 56.0 58.5 63.8 64.7

As shown in Table 2, the interior material of the present invention can be seen that the sound insulation effect is superior to the mat using a conventional resin felt.

Therefore, it can be seen that the interior materials for automobiles of the present invention are excellent interior materials having both sound absorption and sound insulation effects based on the sound absorbing and sound insulating force measurement results.

In addition, the thicker the material and the bulkier the product, the higher the flaw resistance, and the thinner the thickness and the higher the specific gravity, the better the sound insulation.

As described above, in the automotive interior material of the present invention, a thermoplastic material such as polypropylene and polyester is used for the skin layer and the back layer, and only the preheating and the pressure are required without the use of a separate harmful bond in the bonding with the intermediate layer. At the same time, adhesion is possible, which not only improves the harmful working environment, but is also simple in terms of process, thereby achieving low cost and high quality.

In addition, various accessories to be mounted on the interior material can be molded at the same time, making a great contribution to the simplification of the process.

As a material of the interior material for automobiles of the present invention, environmentally friendly hemp fibers and thermoplastic resins such as polypropylene and polyester can be used for recycling and weight reduction of the product.

Therefore, the automotive interior material of the present invention is excellent in strength, moldability, heat resistance, impact resistance, sound absorption and sound insulation.

Claims (3)

In automotive interior materials, a skin layer in which polypropylene: polyester is mixed at a ratio of 8: 2, an interlayer in which polypropylene: hemp fiber is mixed at a ratio of 5: 5, and a polypropylene: polyester ratio of 3: 7. Interior materials for automobiles, characterized in that the back layer is mixed with delete delete