KR20230142042A - Trunk interior material for electric vehicle using single material and manufacturing method therefor - Google Patents

Abstract

The present invention relates to a trunk interior material for an electric vehicle using a single material and a method of manufacturing the same. Specifically, it uses a PP single material and laminates closed structure PP foam and open structure PP foam. The purpose is to provide a trunk interior material for an electric vehicle that is lightweight, has excellent mechanical properties, sound insulation, and sound absorption, and has excellent formability with little distortion after molding, and a manufacturing method thereof.

Description

Trunk interior material for electric vehicle using single material and manufacturing method therefor}

The present invention relates to a trunk interior material for an electric vehicle using a single material and a method of manufacturing the same. Specifically, it uses a PP single material and laminates closed structure PP foam and open structure PP foam. The present invention relates to a trunk interior material for an electric vehicle that is lightweight, has excellent mechanical properties, sound insulation, and sound absorption, and has excellent formability with little distortion after molding, and a method of manufacturing the same.

As the recent industrial megatrend progresses in the direction of eco-friendliness and human-friendliness, materials used in transportation devices such as cars, trains, and aircraft are also responding to environmental friendliness, lightweighting, and high durability, making eco-friendly and lightweight, which are the biggest challenges of the automobile industry. And the development of lightweight composite materials with high durability is required.

Non-woven composite materials have been widely used as sound absorbing and insulating materials to block vehicle noise. However, in response to the lightweighting of vehicles, there is a strong demand for lightweight non-woven composite materials as sound absorbing and insulating materials for vehicles. The demand for non-woven composite materials that have good mechanical properties and can effectively block and reduce noise is increasing.

Due to the absence of an engine in electric vehicles, it is essential to develop Luggage Side Trim, an important vehicle interior component that reduces noise and vibration from the motor, car wheels, external noise from the trunk, and the road surface, and is required for recycling after use. A single material is used.

Non-woven composite materials used as interior and exterior materials for sound absorption and insulation of electric vehicles have various structures and are manufactured in various forms depending on the location at which they are installed in the vehicle. For example, prior art related to weight reduction is presented in Patent Document 1. The high-performance lightweight composite plate has an inner layer (2) composed of 40 to 90% by weight of the base material and 10 to 60% by weight of natural fibers, and is attached to at least one surface of the inner layer (2), and has a base material of 60 to 60% by weight. A lightweight composite board for automobile interior materials is disclosed, which is characterized by consisting of a skin layer (1, 3) composed of 80% by weight of polyester, 15 to 25% by weight of natural fiber, and 5 to 15% by weight of natural fiber.

In Patent Document 2, it is made of a PET (polyethylene terephthalate) foam sheet with a foaming ratio of 10 to 30, a core layer with a thickness of 2 to 8 mm, and a PET foam sheet with a foaming ratio of 2 to 10, and the thickness is 1 to 10. 5 mm, and is lightweight and moldable, comprising a pair of reinforcing layers bonded to the upper and lower surfaces of the core layer by heat lamination, and a polyester-based nonwoven fabric bonded to one side of the reinforcing layer. A substrate for vehicle interior materials with excellent properties is disclosed, and in Patent Document 3, by forming an inorganic fiber mat on one or both sides of a foam layer formed of polyester resin foam, it has a thin thickness and excellent lightness, flame resistance, flexural strength, We are disclosing interior and exterior materials for vehicles that have properties such as sound absorption and sound insulation.

Patent Document 4 includes a polyester foam sheet; The polyester foam sheet has a structure in which an average of 20 or more non-penetrating holes are formed on the surface per unit area of 1 cm in width and 1 cm in height; The non-penetrating hole has a depth ranging from 20 to 80% of the thickness of the polyester foam sheet, an average diameter of 1 mm or less, and a ratio of the average diameter to the average depth of 1.5 to 4.8. is starting.

KR 10-1015513 B1 KR 10-1567777 B1 KR 10-1997617 B1 KR 10-2006415 B1

The problem to be solved by the present invention is that the present invention relates to a trunk interior material for an electric vehicle using a single material and a method of manufacturing the same. Specifically, a PP single material is used, and a closed structure PP foam and an open structure are used. The purpose is to provide a trunk interior material for an electric vehicle that is lightweight, has excellent mechanical properties, sound insulation, and sound absorption, and has excellent moldability with little distortion after molding, and a manufacturing method thereof by laminating PP foam.

As a means of solving the problem according to the present invention, a trunk interior material for an electric vehicle using a single material is sequentially laminated with a skin layer, a PP film layer, a sound insulation layer, a sound absorption layer, a PP film layer, and a back layer.

Another embodiment of the trunk interior material for an electric vehicle using a single material according to the present invention includes a skin layer made of PP nonwoven fabric with a weight of 200 to 300 g/m2, a PP film layer with a weight of 80 to 120 g/m2, and a closed structure. and a sound-insulating layer of PP foam with a weight of 200 to 300 g/m2, a sound-absorbing layer of PP foam with an open structure and a weight of 200 to 300 g/m2, a PP film layer with a weight of 80 to 120 g/m2, and a PP non-woven fabric. The back layers weighing 250 to 350 g/m2 are sequentially laminated.

As a means of solving another problem of the present invention, a trunk interior material for an electric vehicle using a single material is a). Step of preparing a skin layer of a nonwoven fabric made of PP nonwoven fabric with a weight of 200 to 300 g/m2 and a back layer of a nonwoven fabric made of PP nonwoven fabric and a weight of 200 to 300 g/m2, b). Prepare a sound insulation layer of PP foam weighing 200 ~ 300g/㎡ by mixing PP resin with a crosslinker, antioxidant, and filler and foaming the melted resin with a foaming agent to manufacture a closed structure PP foam sheet. Step c). Based on PP resin, cross-linking agent, foaming agent and other additives are kneaded and then foamed by chemical cross-linking or transfer line cross-linking foaming method to produce open structure PP foam sheets, and the weight is 200 to 300 g/㎡. Preparing the sound-absorbing layer of foam, d). Step of preparing a combination of the prepared skin layer and the closed structure PP foam sheet sound insulation layer using a PP film, e). Step of preparing a combination of the prepared back layer and the open structure PP foam sheet sound-absorbing layer using a PP film, f). It includes the step of laminating and laminating so that the sound insulating layer of the combination of the prepared skin layer and the sound insulating layer and the sound absorbing layer of the prepared combination of the back layer and the sound absorbing layer face each other.

In steps d) and steps e), the step of preparing a composite using a PP film is combined by laminating by heating.

The sound insulation layer (2) is used by drying at 130°C to remove moisture before foaming PP, and then adding 1 part by weight of pyromellitic anhydride and 3 parts of calcium carbonate as a crosslinking agent for 100 parts by weight of PET from which moisture was removed in an extruder. Add 0.1 part by weight of antioxidant and 0.1 part by weight of antioxidant, melt by heating to 280 ± 5°C while mixing, then put the resin melt into an extruder, inject foaming agent, and foam into a sheet. The average thickness is 2.5 mm, and the entire cell is manufactured. About 97±1% of cells are closed cells, the average number of cells is 12±5 per 1㎟, and the average cell size is 450±20㎛.

Existing interior materials for electric vehicles using foam sheets have a problem of forming a non-woven fabric layer only on one side of the skin layer, causing distortion after molding, but the trunk interior material for electric vehicles using a single material according to the present invention has a closed structure. Vehicle interior materials using foam and PP foam with an open structure have the advantage of forming a non-woven fabric layer on both the skin layer and the back layer, thereby suppressing distortion after molding into the desired shape.

The trunk interior material for electric vehicles using a single material according to the present invention is a sound-insulating layer of PP foam with a closed structure and a sound-absorbing layer of PP foam with an open structure, so that the vehicle interior material is lightweight and sound-insulating. , It has excellent sound absorption and good mechanical properties such as flexural strength and flexural modulus, making it particularly suitable as an interior material for the trunk lid, trunk side, and trunk partition of electric vehicles.

The trunk interior material for an electric vehicle using a single material according to the present invention is easy to recycle because it uses a single material.

Figure 1 shows a laminated structure of trunk interior materials according to the prior art.
Figure 2 shows the laminated structure of the trunk interior material for an electric vehicle using a single material according to the present invention.
Figure 3 is an example of a trunk side interior material for an electric vehicle using a single material according to the present invention.
Figure 4 is a sound absorption coefficient graph of the trunk interior material for an electric vehicle using a single material according to the present invention.

Hereinafter, the present invention will be described in more detail with specific details for carrying out the present invention, but the present invention is not limited to the details and examples described below.

The trunk interior material for an electric vehicle using a single material according to the present invention has a skin layer (1), a PP film layer (2), a sound insulation layer (3), a sound absorption layer (4), a PP film layer (5), and a back layer (6). are stacked sequentially.

Specifically, the skin layer 1 is made of PP nonwoven fabric and has an area density of 200 to 300 g/m2.

The sound insulation layer 3 has a closed structure and is in the form of a PP foam sheet with a weight of 200 to 300 g/m2. The sound insulation layer (3) plays a role in blocking low-frequency noise, such as the impact sound of fine particles from the bottom of the electric vehicle and the wheels, and blocks noise below 2000Hz. However, it also has sound absorption performance due to the pores in the PP foam, which is the sound insulation layer (3).

The sound-absorbing layer 4 has an open structure and is in the form of a PP foam sheet with a weight of 200 to 300 g/m2. The sound-absorbing layer 4 plays a role in absorbing high-frequency noise generated from the motor of an electric vehicle, and absorbs noise above 3000 Hz.

The back layer 6 is made of PP non-woven fabric and has an area density of 250 to 350 g/m2.

The PP nonwoven fabric of the skin layer (1) and the back layer (6) according to the present invention is made from short fibers of 2 to 10 denier as raw materials, and is made by using a widely known nonwoven fabric manufacturing method such as carding process, web forming process, and web bonding (adhesion). ) Non-woven fabric is manufactured through a process and is not particularly limited.

The PP film layers (2) and (5) according to the present invention act as a binder to combine the skin layer (1), the sound insulation layer (3), the sound absorption layer (4), and the back layer (6). The PP film layers (2) and (5) are PP films with a weight of 80 to 120 g/m2.

The sound insulation layer (3) according to the present invention is made of a closed structure PP foam sheet made by foaming PP resin, and exhibits a sound insulation function. The sound insulation layer 3 is preferably a foam sheet of 200 to 300 g/m2.

In general, Closed Structure Foam has high compressive strength, is light, flexible, strong, and durable enough to withstand a large amount of pressure without most major distortions, and has stronger structural properties than Open Structure Foam. There is. The closed foam of the present invention has high sound insulation, while the open foam has high sound absorption.

The sound insulation layer (3) of the present invention reduces the weight per unit area and improves mechanical properties such as flexural strength and flexural modulus of elasticity due to the material and structural characteristics of the closed structure PP foam sheet made by foaming PP.

The method of manufacturing a trunk interior material for an electric vehicle using a single material according to the present invention is a). Step of preparing a skin layer (1) made of PP nonwoven fabric with a weight of 200 to 300 g/m2 and a back layer (6) made of PP nonwoven fabric and weighing 200 to 300 g/m2, b). A PP foam sheet with a closed structure is manufactured by mixing PP resin with a crosslinker, antioxidant, and filler and foaming the melted resin with a foaming agent to produce a sound insulation layer of PP foam weighing 200 to 300 g/m2 (3). ) and c). It is based on PP resin, mixed with cross-linking agent, foaming agent and other additives, and then foamed by chemical cross-linking or transfer line cross-linking foaming method to produce an open structure PP foam sheet with a weight of 200 to 300 g/㎡. Step of preparing the sound-absorbing layer (4) of PP foam, d). Step of preparing a combination of the prepared skin layer (1) and the closed structure PP foam sheet sound insulation layer (3) using a PP film, e). Step of preparing a combination of the prepared back layer (6) and the open structure PP foam sheet sound-absorbing layer (4) using a PP film, f). It consists of laminating and laminating the combination sound insulating layer 3 of step d) and the combination sound absorbing layer 4 of step e) so that they face each other.

The step of preparing the skin layer (1) and the back layer (6) according to the present invention is a carding process, web forming process, and web bonding, which are widely known nonwoven fabric manufacturing methods using PP staple fibers of 2 to 10 denier as raw materials. Nonwoven fabric is manufactured through an (adhesion) process and is not particularly limited.

The step of preparing the sound insulation layer 3 according to the present invention consists of foaming PP with a foaming agent to manufacture a closed structure PP foam sheet with a weight of 200 to 300 g/m2.

The PP closed structure PP foam sheet is made by first melting the raw resin by mixing additives such as crosslinking agents, antioxidants, and fillers, and then foaming and molding the resin melt into a sheet with a foaming agent using a compressor. It comes true.

The PP closed structure PP foam sheet is used by drying the raw material PP at 130°C to remove moisture before foaming, and pyromellitic anhydride is added as a crosslinking agent for 100 parts by weight of PP from which moisture has been removed in the extruder. Add 1 part by weight of calcium carbonate, 3 parts by weight of calcium carbonate, and 0.1 part by weight of Irganox 1010 (brand name) as an antioxidant, heat and melt at 280 ± 5°C while mixing, then put the resin melt into an extruder and add a foaming agent, such as butane gas. It is manufactured by injecting and foaming into a sheet.

The closed structure PP foam sheet of the sound insulation layer (3) manufactured according to the present invention has a unit weight of 200 to 300 g/m2, an average thickness of 2.5 mm, and about 97 ± 1% of the total cells. It is a closed structure, with an average number of cells of 12±5 per 1㎟ (average size: 450±20㎛). The foam sheet preferably has a unit weight of 150 to 400 g/m2.

The step of preparing the sound-absorbing layer 4 according to the present invention consists of foaming PP with a foaming agent to manufacture an open structure PP foam sheet with a weight of 200 to 300 g/m2.

The sound-absorbing layer (4) is a foam based on PP resin and manufactured by chemical cross-linking or transfer line cross-linking foaming method after mixing cross-linking agent, foaming agent and other auxiliaries. It is manufactured by a conventional PP foam manufacturing method. .

Since the sound insulating layer (3) and the sound absorbing layer (4), which are the laminated structure of the sound insulating layer (3) and the sound absorbing layer (4) of the trunk interior material for an electric vehicle according to the present invention, are made of the same material, in manufacturing, adhesives, etc. It has the advantage of being a simple process because it does not require this.

The lamination step according to the present invention combines the skin layer (1) prepared in step a) and the sound insulation layer (3) prepared in step b) via a PP film, and the back layer (6) prepared in step a) and step c). The sound-absorbing layers 4 prepared in are joined by heating through a PP film.

Afterwards, the combined sound insulating layer (3) prepared in step d) and the combined sound absorbing layer (4) prepared in step e) are stacked face to face, laminated, and then molded.

The trunk interior material for electric vehicles using a single material according to the present invention has high sound insulation due to the closed structure of the PP foam sheet structure of the sound insulation layer (3) and the open structure of the sound absorption layer (4). It has high sound absorption due to the PP foam sheet structure, is lightweight, and has good mechanical properties such as flexural strength and flexural modulus, making it particularly suitable as a composite material for the trunk lid, trunk side, and trunk partition of electric vehicles.

The trunk interior material for electric vehicles using a single material according to the present invention has the advantage of suppressing distortion after molding and processing into the desired shape by having a non-woven fabric layer on the upper surface (skin layer) and the lower surface (back layer). Since it has a non-woven fabric layer only on the top surface (skin layer), it has the advantage of solving the problem of distortion after molding and processing into the desired shape.

Hereinafter, the present invention will be described in more detail through specific <Examples> and <Test Examples>.

<Example>

- Production of epidermal layer (1)

Needle non-woven fabric (200 g/m2) was manufactured by carding, cross-lapping, and needle-punching 6-denier PP short fibers.

- Manufacturing of back layer (6)

Needle non-woven fabric (250 g/m2) was manufactured by carding, cross-lapping, and needle-punching 6-denier PP short fibers.

- Manufacture of sound insulation layer (3)

The closed structure PP foam sheet of the sound insulation layer (3) is used by drying the raw material PP at 130°C to remove moisture in advance before foaming, and adding a crosslinking agent to 100 parts by weight of PET from which moisture has been removed in the extruder. Add 1 part by weight of pyromellitic anhydride, 3 parts by weight of calcium carbonate, and 0.1 part by weight of Irganox 1010 (brand name) as an antioxidant, heat to 280°C while mixing to melt, then put the resin melt into an extruder and add a foaming agent, such as It was manufactured by injecting butane gas and foaming it into a sheet shape.

The manufactured closed structure PP foam sound insulation layer (3) weighs 250 g/㎡.

- Manufacture of sound-absorbing layer (4)

The open structure PP foam sheet of the sound-absorbing layer (4) was manufactured by mixing the raw material PP with a crosslinking agent, foaming agent, and other additives, and then using a transfer wire crosslinking foaming method.

The manufactured open structure PP foam sound-absorbing layer (4) weighs 250 g/m2.

- Combination of epidermal layer (1) and sound insulation layer (3)

A composite was manufactured by heating and bonding the skin layer (1) and the sound insulation layer (3) through a PP film.

- Combination of back layer (6) and sound-absorbing layer (4)

A composite was prepared by heating and bonding between the back layer (6) and the sound-absorbing layer (4) using a PP film.

- Lamination of interior materials

A single-material electric vehicle trunk is made by stacking the sound insulation layer (3) of the combination of the skin layer (1) and the sound insulation layer (3) and the sound absorption layer (4) of the combination of the back layer (6) and the sound absorption layer (4) facing each other. Interior materials were manufactured.

The mechanical properties of tensile strength and sound absorption were tested for the interior material specimens manufactured in the above <Example>, and the results are shown in [Table 1] below.

density
250g/㎡ tensile strength 1/3 octave center frequency (Hz) M.D.
(Kgf/㎠) CD
(Kgf/㎠) 400Hz 1000Hz 2000Hz 3150Hz 5000Hz 10000Hz Example 1
Sound insulation layer 200g/㎡
Sound absorption layer300g/㎡ 41.2 55.7 0.048 0.194 0.502 0.756 0.874 0.947 Example 2
Sound insulation layer220g/㎡
Sound absorption layer 280g/㎡ 41.7 53.9 0.050 0.194 0.492 0.589 0.880 0.984 Example 3
Sound insulation layer 250g/㎡
Sound absorption layer 250g/㎡ 44.5 56.3 0.53 0.204 0.502 0.772 0.893 0.957 Example 4
Sound insulation layer 270g/㎡
Sound absorption layer 230g/㎡ 42.9 57.0 0.57 0.219 0.476 0.723 0.849 0.893 Example 5
Sound insulation layer 300g/㎡
Sound absorption layer 200g/㎡ 47.4 58.2 0.050 0.203 0.486 0.721 0.861 0.985

* In tensile strength, MD: machine direction, CD: perpendicular to the machine direction.

The test values shown in [Table 1] are the results of testing the tensile strength and sound absorption rate of Examples 1 to 5 by varying the areal density of the sound insulating layer and the areal density of the sound absorbing layer, respectively.

The embodiment satisfies the lower limit of tensile strength required by the demand side of 40Kgf/cm2 or more, and the sound absorption coefficient is required to be more than 0.10 at 1000Hz, more than 0.15 at 2000Hz, more than 0.25 at 3150Hz, and more than 0.32 at 5000Hz, all of which are satisfied. It was confirmed that it represents .

It can be seen that the interior material of the trunk interior material for an electric vehicle using a single material according to the present invention with PP foam having a closed structure and an open structure has excellent sound insulation and sound absorption properties.

Claims (4)

A trunk for an electric vehicle using a single material, characterized by sequential stacking of the skin layer (1), PP film layer (2), sound insulation layer (3), sound absorption layer (4), PP film layer (5), and back layer (6). Interior materials. Skin layer (1) made of PP non-woven fabric with a weight of 200 to 300 g/m2, PP film layer (2) with a weight of 80 to 120 g/m2, and PP foam with a closed structure and a weight of 200 to 300 g/m2. a sound-insulating layer (3), a sound-absorbing layer (4) of PP foam with an open structure and a weight of 200 to 300 g/m2, a PP film layer (5) with a weight of 80 to 120 g/m2, and a PP non-woven fabric. A trunk interior material for an electric vehicle using a single material, characterized in that back layers (6) weighing 250 to 350 g/m2 are sequentially stacked and combined. a). Preparing a skin layer (1) made of PP nonwoven fabric with a weight of 200 to 300 g/m2 and a back layer (6) made of PP nonwoven fabric and weighing 200 to 300 g/m2,
b). A PP foam sheet with a closed structure is manufactured by mixing PP resin with a crosslinker, antioxidant, and filler and foaming the melted resin with a foaming agent to produce a sound insulation layer of PP foam weighing 200 to 300 g/m2 (3). ) steps to prepare,
c). It is based on PP resin, mixed with cross-linking agent, foaming agent and other additives, and then foamed by chemical cross-linking or transfer line cross-linking foaming method to produce an open structure PP foam sheet with a weight of 200 to 300 g/㎡. Preparing a sound-absorbing layer (4) of PP foam,
d). Preparing a combination of the prepared skin layer (1) and the closed structure PP foam sheet sound insulation layer (3) using a PP film,
e). Preparing a combination of the prepared back layer (6) and the open structure PP foam sheet sound-absorbing layer (4) using a PP film,
f). A method of manufacturing a trunk interior material for an electric vehicle using a single material, comprising the step of laminating and laminating the combination sound insulating layer 3 of step d) and the combination sound absorption layer 4 of step e) so that they face each other. . In claim 3,
The sound insulation layer (3) is used by drying at 130°C to remove moisture before foaming PP, and then adding 1 part by weight of pyromellitic anhydride and 3 parts by weight of calcium carbonate as a crosslinking agent for 100 parts by weight of PET from which moisture was removed in the extruder. Add 0.1 part by weight of the resin and antioxidant, melt it by heating to 280 ± 5°C while mixing, then put the resin melt into an extruder, inject a foaming agent, and foam it into a sheet shape. The average thickness is 2.5 mm, and the total cell thickness is 2.5 mm. Approximately 97±1% are closed cells, the average number of cells is 12±5 per 1㎟, and the average cell size is 450±20㎛. A method of manufacturing a trunk interior material for an electric vehicle using a single material. .