KR20200030221A - Underfloor For Automobile - Google Patents

Abstract

The present invention relates to an underfloor for an automobile. More specifically, the present invention, by maintaining the same or similar mechanical performance compared to an existing underfloor for the automobile and realizing 20 to 30% of weight reduction, can provide the underfloor for the automobile which can contribute to the weight reduction and enhancement of the automobile, has a sound absorption function and a sound insulation function for each section, and at the same time, has excellent insulation and heat-resistance/cold-resistance effects.

Description

Vehicle Underfloor {Underfloor For Automobile}

The present invention relates to an underfloor for a vehicle, and provides an underfloor for a vehicle having excellent rigidity of a nonwoven fabric layer and eliminating occurrence of warpage.

Entering the 21st century, the auto parts market focuses on technology development to improve lightness, fuel efficiency, use of eco-friendly materials, high performance, and stability in the global flow of strict international environmental regulations related to rising oil prices and reducing CO ₂ emissions. have.

In the case of automobile interior materials, where various textile products are applied, we are focusing on the development of new lightweight automobile interior parts, mainly in developed countries such as Europe, the United States, and Japan, and in particular, reducing the weight of previously used metal materials and plastic injection materials. To this end, product development using high-performance fibers is actively taking place.

When the weight of the vehicle is reduced by 1%, the fuel efficiency increases by 1%, so in developed countries such as Europe, the United States, and Japan, the development of automotive interior parts using light-weight needle punching non-woven fabrics and 3D spacer fabrics using glass fibers is actively underway. , It is actively researching and developing to replace existing metal or injection products by utilizing high-strength super fibers such as carbon fiber and aramid fiber.

Among the parts for automobile interior parts applied in Korea, parts such as under cover, engine cover, and dash insulation applied to the engine room that require high mechanical properties and heat resistance are conventionally composed of waste fiber and phenol resin composite resin resin and natural fiber. Materials such as HS-Felt mixed with wood and Wood Stock mixed with wood were mainly used as sound absorbing materials, and GMT or PP injection material is applied as a reinforcing material, so the weight of the product is high.

These products have been attempted to be applied to lightweight engine cover parts by replacing the existing injection material in Korea, but in overseas, they exhibit durability problems in a low-temperature environment as a cause of the impact strength of the glass fiber nonwoven fabric, and the engine room that continuously occurs It causes problems such as deterioration of sound absorption and sound insulation performance and durability at high temperatures.

Accordingly, advanced companies such as the United States and Japan are actively developing composite sound-absorbing materials utilizing super fibers to secure high durability and excellent sound absorption and sound insulation performance in high temperature and cold environments by replacing non-woven glass fiber products.

In this way, it is urgent to develop a super-fiber composite sound absorbing material for automobile engine under covers, which is expected to continue to increase in demand by developing world-class products with its own technology to avoid the dependence of advanced technology of domestic auto parts materials amid changing industrial environments.

Common low-melting point (LM) yarn used in the composite sound absorbing material has a melting point of 110 ° C, so the melting point is low, resulting in a decrease in stiffness after underflow molding and a decrease in flexural strength or flexural modulus, resulting in bending. There was.

Republic of Korea Patent Publication No. 10-2018-0009918 (released on January 30, 2018)

Therefore, according to the present invention, by solving the problems in the case of using the existing general LM, excellent rigidity of the non-woven fabric layer, and by providing an underfloor for a vehicle in which no warpage occurs, flame retardancy, heat resistance, heat shielding property is excellent, room temperature Of course, it is a technical task to provide an underfloor for a vehicle, which is a heat-absorbing sound-absorbing and heat-resistant material that can be applied to parts such as an engine hood where high temperature is maintained, and can be molded.

Therefore, according to the present invention, the first non-woven fabric layer (10) made of low melting point (Low Melting) fibers and polyethylene terephthalate (PET) fibers made of RM (Rapid Melting fiber) fibers;

A bonding layer 20 made of polyethylene terephthalate (PET) powder;

Including; but, a second non-woven layer (30) made of low melting point (Low Melting) fibers made of LM (Low Melting fiber) fibers and polyethylene terephthalate (PET) fibers;

An underfloor for a vehicle is provided, wherein the first nonwoven layer 10, the bonding layer 20, the second nonwoven layer 30, and the first nonwoven layer 10 are sequentially stacked and combined.

In addition, the first nonwoven layer 10 of the vehicle underfloor of the present invention is 20 to 80% by weight of low melting fibers made of Rapid Melting Fiber (RM) fibers, and polyethylene terephthalate (PET) fibers 20 to 80% by weight,

The second nonwoven layer 30 is characterized in that the low melting fiber (Low Melting) made of LM (Low Melting fiber) fiber is 40 to 50% by weight, and the polyethylene terephthalate (PET) fiber is 50 to 60% by weight. do.

The polyethylene terephthalate (PET) powder of the bonding layer 20 of the underfloor for a vehicle of the present invention is characterized in that it has a particle size of 250 to 350㎛.

Therefore, according to the present invention, by maintaining the same or similar mechanical performance compared to the existing underfloor for a vehicle, and realizing a weight reduction of 20 to 30%, it can contribute to weight reduction and luxury of the vehicle, and has sound absorption and sound insulation functions for each section. Excellent insulation and heat / cold effect.

1 is a schematic lower view of a vehicle showing a position in which a vehicle underfloor of the present invention is applied in a vehicle,
2 is a cross-sectional view showing the structure of a vehicle underfloor of the present invention.
3 is a photograph of an embodiment of an underfloor for a vehicle of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately explains the concept of terms in order to explain his or her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

Therefore, the configuration shown in the embodiments and drawings described in this specification is only one of the most preferred embodiments of the present invention and does not represent all of the technical spirit of the present invention, and various equivalents can be substituted for them at the time of application. It should be understood that there may be water and variations.

1 is a schematic lower view of a vehicle showing a position to which a vehicle underfloor of the present invention is applied in a vehicle. Referring to Figure 1, the underfloor mounted on the lower part of the car can be divided into three parts, the engine under cover (1), the rear floor (3) and the engine under cover (1) and the rear floor (3) under the engine room ) There is an underfloor (2) for dividing the middle portion located between, the vehicle underfloor of the present invention can be applied to the underfloor (2) and the rear floor (3).

This is because, unlike the engine undercover 1 where heat is generated, the middle and rear ends of the vehicle without a driving part can maintain a normal temperature state, so that it is possible to apply a separate underfloor separately from the undercover that requires heat resistance. will be. In other words, sound insulation that blocks noise generated from sand, gravel, etc., vehicle rain that satisfies the impact resistance that protects the lower part of the vehicle from collisions with small objects such as rainwater, and gravel, and heat resistance that insulates heat from summer and winter outside air. I would like to provide a floor.

As illustrated in FIG. 2, the underfloor for a vehicle according to the present invention includes a first nonwoven layer 10 made of low melting fiber and polyethylene terephthalate (PET) fiber made of rapid melting fiber (RM) fibers;

A bonding layer 20 made of polyethylene terephthalate (PET) powder;

Including; but, a second non-woven layer (30) made of low melting point (Low Melting) fibers made of LM (Low Melting fiber) fibers and polyethylene terephthalate (PET) fibers;

The first non-woven fabric layer 10, the bonding layer 20, the second non-woven fabric layer 30 and the first non-woven fabric layer 10 are sequentially stacked and combined.

In the first nonwoven layer, polyethylene terephthalate (PET) fiber serves as a body that imparts durability and morphology, that is, a substrate, and has fine pores with many voids between fibers, so it can have excellent sound absorption. The low melting fiber serves to bond the polyethylene terephthalate (PET) fibers that are melted to form a base layer, and plays an important function in satisfying the tensile strength, flexural strength, and bone elastic modulus required in the vehicle underfloor. Perform.

Conventional LM has a melting point of 110 ° C, which has a low melting point, resulting in a decrease in stiffness after forming underfloor and a decrease in flexural strength or flexural modulus, resulting in bending, but RM (Rapid) of the first nonwoven layer. Melting fiber) The low melting fiber composed of fibers is preferably 160 to 180 ° C., which has a high melting point and a high melting point, so that it melts quickly at a temperature and hardens, so it is preferable because it has the advantage of eliminating bending.

In particular, the first nonwoven layer 10 is 20 to 80% by weight of low-melting (Low Melting) fibers made of Rapid Melting fiber (RM) fibers, 80 to 20% by weight of polyethylene terephthalate (PET) fibers Preferably, the second nonwoven layer 30 is 40 to 50% by weight of low melting fiber (Low Melting) made of LM (Low Melting fiber) fiber, 50 to 60% by weight of polyethylene terephthalate (PET) fiber It is preferred.

When the low-melt fiber of the second nonwoven layer is included in 40 to 50 parts by weight, the bonding strength of the polyethylene terephthalate (PET) fiber serving as the base layer is increased, and it is possible to solve the problem of tearing when forming an underfloor finished product. Water-based is secured and durability can be maintained. In addition, when the low-melt fiber is less than 40 parts by weight, both the tensile strength, the flexural strength, and the bone elastic modulus decrease, and when the low-melt fiber exceeds 50 parts by weight, the tensile strength and flexural strength increase, while the bone elastic modulus decreases.

When the polyethylene terephthalate (PET) fiber is contained in less than 50 parts by weight, the body that gives durability and morphology is difficult to serve as a substrate, and when the polyethylene terephthalate (PET) fiber exceeds 60 parts by weight, the substrate layer The binding strength of the base layer may be insufficient due to the lack of the low-melting fiber that bonds.

The bonding layer is interposed between the non-woven fabric layers to serve to bind the non-woven fabric layer by heating, and has a high density, excellent sound insulation performance, strong impact resistance, and electrical insulation properties. The polyethylene terephthalate (PET) powder of the bonding layer 20 may have a particle size of 250 to 350 μm uniformly permeate the nonwoven layer to improve the binding force.

When explaining an embodiment of a method for manufacturing an underfloor for a vehicle of the present invention is as follows. Low Melting Fiber (PE) made of Rapid Melting Fiber (RM) fiber and Polyethylene Terephthalate (PET) fiber are mixed by carding and then laminated to form a first nonwoven layer 10 by needle punching. Low Melting fiber (Low Melting fiber) made of LM (Low Melting) fiber and polyethylene terephthalate (PET) fibers are carded and blended, respectively, and then laminated and needle punched to form a second nonwoven layer (30).

The polyethylene terephthalate (PET) powder is coated between the first nonwoven fabric layer 10 and the second nonwoven fabric layer 30 prepared as described above to form a bonding layer 20. After the first nonwoven layer 10 is further added to the lower portion of the second nonwoven layer 30, after preheating at 200 to 300 ° C for 1 minute and 20 seconds to 2 minutes, the mold is heated to a temperature of 10 to 15 ° C. By cold forming, an underfloor for a vehicle of a desired shape is manufactured.

[Example 1]

Carding, blending, lamination, needle punching (4 parts) of 160 parts by weight of low melting fiber and polyethylene terephthalate (PET) fiber composed of RM (Rapid Melting fiber) fibers based on 400 parts by weight of the first nonwoven layer, respectively Times) to prepare a first nonwoven fabric layer. Based on 400 parts by weight of the second nonwoven layer, 240 parts by weight of polyethylene terephthalate (PET) fiber and 160 parts by weight of low melting fiber (LM) fiber, which is a low-melting fiber, are carded, blended, laminated, and needle punched (4 times), respectively. A nonwoven layer was prepared. Positioning the second nonwoven layer on top of the first nonwoven layer, applying 100 parts by weight of polyethylene terephthalate (PET) powder again on top of the second nonwoven layer, and placing the other first nonwoven layer to total 4 After lamination by laminating layers and passing through a roller, heat treatment was performed at 250 ° C for 1 minute and 30 seconds, followed by cooling, and then cooled and molded in a mold at a temperature of 15 ° C for 40 seconds to prepare an underfloor for a vehicle.

To measure the mechanical strength of the underfloor for a vehicle manufactured in Example 1, 5 samples of 150 mm × 50 mm in length were prepared and left for 3 days at a temperature of 23 ± 3 ° C. and a humidity of 50 ± 5%, Tensile test, flexural test, and flexural modulus test according to ASTM D638 standard were performed. Table 1 is a measurement of physical properties of Example 1.

Evaluation items unit Example 1 Assessment Methods 1. Tensile strength N 800 ASTM D 5034-2008 2. Heat resistance (shrinkage) % 5% MS 341-18 3..Flame retardant mm / min 80 MS 300-08 4. Light weight g / ㎡ 1475 g MS 343-11 5. Flexural strength N 10 ISO 178

10: first non-woven fabric layer 20: bonding layer
30: second non-woven layer

Claims (3)

A first nonwoven layer 10 made of low melting fiber and polyethylene terephthalate (PET) fiber made of rapid melting fiber (RM) fibers;
A bonding layer 20 made of polyethylene terephthalate (PET) powder;
Including; a second nonwoven layer 30 made of low melting point (Low Melting) fibers made of LM (Low Melting fiber) fibers and polyethylene terephthalate (PET) fibers;
The underfloor for a vehicle, characterized in that the first nonwoven layer 10, the bonding layer 20, the second nonwoven layer 30, and the first nonwoven layer 10 are sequentially stacked and combined. According to claim 1,
The first nonwoven layer 10 is composed of RM (Rapid Melting fiber) fibers, low-melting (Low Melting) fibers are 20 to 80% by weight, polyethylene terephthalate (PET) fibers are 20 to 80% by weight,
The second nonwoven layer 30 is characterized in that the low melting fiber (Low Melting) made of LM (Low Melting fiber) fiber is 40 to 50% by weight, and the polyethylene terephthalate (PET) fiber is 50 to 60% by weight. Vehicle underfloor. According to claim 1,
Polyethylene terephthalate (PET) powder of the bonding layer 20 is a vehicle underfloor, characterized in that the particle size of 250 to 350㎛.

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