阅读说明：本技术 具有高弹性和高刚性的用于车辆的底罩及其制造方法 (Under cover for vehicle having high elasticity and high rigidity and method for manufacturing the same ) 是由 金成制 金槿英 金泰润 李廷勖 金永洙 河宗彦 于 2019-12-04 设计创作，主要内容包括：本发明公开了具有高弹性和高刚性的用于车辆的底罩及其制造方法。具有高弹性和高刚性的用于车辆的底罩可以包括针刺非织造物,所述针刺非织造物具有毡层的多层结构,所述毡层包括第一PET纤维和低熔点PET纤维,并且每个毡层均可以具有改善的拉伸强度和优化的纤维排列,由此改善纤维之间的结合,机械刚性和弹性,以及减少部件的重量,改善耐久性并确保无害性和在线可加工性。(The invention discloses a bottom cover for a vehicle having high elasticity and high rigidity and a method for manufacturing the same. The under cover for a vehicle having high elasticity and high rigidity may include a needle punched nonwoven having a multi-layer structure of felt layers including first PET fibers and low melting point PET fibers, and each of the felt layers may have improved tensile strength and optimized fiber arrangement, thereby improving bonding between fibers, mechanical rigidity and elasticity, and reducing weight of parts, improving durability and ensuring harmless and on-line workability.)

1. A undercover for a vehicle, comprising:

a needle-punched nonwoven formed by needle-punching a first nonwoven layer comprising one or more first felt layers and a second nonwoven layer formed on the first nonwoven layer and comprising one or more second felt layers,

wherein the first and second felt layers each comprise a web comprising first polyethylene terephthalate fibers in an amount of 1 to 40 weight percent and low melting polyethylene terephthalate fibers in an amount of 60 to 99 weight percent, based on the total weight of the web.

2. The under cover for a vehicle according to claim 1, wherein the first nonwoven layer and the second nonwoven layer each comprise a first felt layer and a second felt layer laminated as a multilayer structure of two or three layers.

3. The under-cover for a vehicle of claim 1, wherein the first and second nonwoven layers each comprise a web comprising fibers of the first and second felt layers randomly mixed in a horizontal and vertical arrangement.

4. The under cover for a vehicle according to claim 1, wherein the first nonwoven layer and the second nonwoven layer each have 300g/m²～750g/m²Weight per unit area of (c).

5. The under cover for a vehicle according to claim 1, wherein the first nonwoven layer and the second nonwoven layer are repeatedly laminated in a multilayer structure of three to five layers.

6. The under cover for a vehicle according to claim 1, wherein the first polyethylene terephthalate fiber has a melting point of 240 ℃ to 270 ℃, a fiber length of 48mm to 76mm, and a tensile strength of 3g/De to 4 g/De.

7. The under cover for a vehicle according to claim 1, wherein the low melting point polyethylene terephthalate fiber has a melting point of 105 to 180 ℃, a fiber length of 48 to 76mm, and a tensile strength of 3 to 4 g/De.

8. The undercover for vehicle of claim 1 wherein the needle punched nonwoven has 600g/m²～1500g/m²Weight per unit area of (c).

9. The under cover for vehicle according to claim 1, wherein the needle-punched non-woven fabric has a number of needle-punching times of 20 to 80 punches/cm²。

10. A method of manufacturing a undercover for a vehicle having high elasticity and high rigidity, the method comprising:

providing a first polyethylene terephthalate fiber having a melting point of 240-270 ℃ and a low-melting-point polyethylene terephthalate fiber having a melting point of 105-180 ℃;

forming a web by carding first polyethylene terephthalate fibers in an amount of 1 to 40 wt% and low melting point polyethylene terephthalate fibers in an amount of 60 to 99 wt%, based on the total weight of the web;

forming each of the first and second felt layers by bonding and hot pressing the fibrous webs;

forming each of the first and second nonwoven layers by laminating the first and second felt layers into two to three layers; and

the needled nonwoven is produced by laminating a second nonwoven layer onto the first nonwoven layer, followed by needling.

11. The method of claim 10, wherein the first polyethylene terephthalate fiber has a fiber length of 48mm to 76mm and a tensile strength of 3g/De to 4 g/De.

12. The method of claim 10, wherein the low melting point polyethylene terephthalate fiber has a fiber length of 48mm to 76mm and a tensile strength of 3g/De to 4 g/De.

13. The method of claim 10, wherein each of the first and second nonwoven layers is formed by repeatedly laminating a web into a three-to-five-layer multilayer structure when forming each of the first and second nonwoven layers.

14. The method of claim 10, wherein in producing the needled nonwoven, the needled nonwoven has a weight of 600g/m²～1500g/m²Weight per unit area of (c).

15. The method according to claim 10, wherein the number of needle punching is 20 to 80 punches/cm in producing the needle punched nonwoven fabric²。

16. A vehicle comprising the under cover for a vehicle according to claim 1.

Technical Field

The present invention relates to a bottom cover (undercover) for a vehicle having high rigidity, which includes a needle-punched nonwoven fabric having a multi-layer structure of felt layers including PET fibers and low-melting PET fibers, each of the felt layers having improved tensile strength and optimized fiber arrangement, and a method of manufacturing the same.

Background

In the related art, a undercover is mounted on the bottom of a vehicle and functions to protect components including an engine and a transmission mounted in the bottom side of the vehicle. The undercover also functions to prevent foreign matter from entering the vehicle from the bottom of the vehicle while traveling. In addition, the undercover plays an important role in absorbing and blocking noise generated from the vehicle (particularly, the engine and the transmission), thereby preventing the noise from being transmitted to the outside of the vehicle.

Conventional materials for the bottom cover include: such as polypropylene and glass fiber reinforced polypropylene composites. However, these materials have disadvantages of low fuel efficiency and poor NVH (noise, vibration, smoothness) performance due to their excessive weight. In particular, glass fiber reinforced polypropylene composites have the problems associated with glass fiber dust and the disadvantage of low durability against external impacts.

To solve these problems in the art, a polyethylene terephthalate material has been used to manufacture the under cover. However, such a polyethylene terephthalate material has less bending rigidity than conventional materials, and thus needs to be made harder in order to improve on-line workability.

The above information disclosed in this background section is only provided to enhance understanding of the background of the invention and therefore the information that it may contain does not constitute prior art that is already known in this country to a person skilled in the art.

Disclosure of Invention

In a preferred aspect, there are provided a undercover for a vehicle having high elasticity and high rigidity due to improved bonding force between fibers and a method of manufacturing the undercover for a vehicle, which can reduce the weight of parts, improve durability, and ensure non-hazardous (safety) and on-line workability.

The objects of the present invention are not limited to those described above. The objects of the present invention will be clearly understood from the following description, and can be achieved by the means defined in the claims and combinations thereof.

In one aspect, a undercover for a vehicle having high elasticity and high rigidity is provided. The bottom cover may include: a needled nonwoven formed by needling a first nonwoven layer comprising one or more first felt layers and a second nonwoven layer formed on the first nonwoven layer and comprising one or more second felt layers. Preferably, the first and second felt layers may each comprise a web comprising polyethylene terephthalate fibers in an amount of about 1 to 40 weight percent and low melting polyethylene terephthalate fibers in an amount of about 60 to 99 weight percent, based on the total weight of the web.

The first and second felt layers may be the same or different. The first and second felt layers may be the same, e.g., have the same composition and content. The first and second felt layers may be different, e.g., having at least one or more different components or different contents of at least one or more components.

If the first and second felt layers are different, it is suitable that at least about 1,2, 3, 4, 5, 10, 15, or 20 weight percent of the first felt layer composition is different from the second layer composition.

Preferably, the first and second nonwoven layers may each comprise: a first felt layer and a second felt layer laminated in a multilayer structure of two or three layers. For example, the first nonwoven layer and the second nonwoven layer may each comprise a first felt layer and a second felt layer laminated as a multilayer structure of two layers

A second felt layer. Also, each of the first and second nonwoven layers may include: a first felt layer and a second felt layer laminated in a three-layer multilayer structure.

The first and second nonwoven layers may each comprise a web comprising fibers of the first and second felt layers randomly mixed in a horizontal and vertical arrangement.

The first nonwoven layer and the second nonwoven layer may suitably have about 300g/m²To 750g/m²Weight per unit area of (c).

The first nonwoven layer and the second nonwoven layer may be repeatedly laminated into a multilayer structure of three to five layers. For example, the first nonwoven layer and the second nonwoven layer may be repeatedly laminated into a multilayer structure of three, four, or five layers.

The polyethylene terephthalate fiber ("first polyethylene terephthalate fiber") may suitably have a melting point of about 240 ℃ to 270 ℃, a fiber length of about 48mm to 76mm, and a tensile strength of about 3g/De to 4 g/De.

The low melting point polyethylene terephthalate fiber may suitably have a melting point of about 105 to 180 ℃, a fiber length of about 48 to 76mm, and a tensile strength of about 3 to 4 g/De. In any aspect, the low melting polyethylene terephthalate fiber has a melting point that is about 5 degrees, 10 degrees, 20 degrees, or 30 degrees lower than the melting point of the first polyethylene terephthalate fiber.

The needle punched nonwoven may suitably have a thickness of about600g/m²To 1,500g/m²Weight per unit area of (c).

The number of needle punching times of the needle punched nonwoven may suitably be about 20 to 80 punches/cm²。

In another aspect, a method of manufacturing a undercover for a vehicle having high elasticity and high rigidity is provided. The method may comprise the steps of: i) providing first polyethylene terephthalate fibers having a melting point of about 240 ℃ to 270 ℃ and low melting point polyethylene terephthalate fibers having a melting point of about 105 ℃ to 180 ℃, ii) forming a web by carding the first polyethylene terephthalate fibers in an amount of about 1 wt% to 40 wt% and the low melting point polyethylene terephthalate fibers in an amount of about 60 wt% to 99 wt% based on the total weight of the web, iii) forming each of the first and second felt layers by bonding and hot pressing the web, iv) forming each of the first and second nonwoven layers by laminating the first and second felt layers into two to three layers, and v) producing a needled nonwoven by laminating the second nonwoven layer on the first nonwoven layer followed by needling.

The first polyethylene terephthalate fiber may suitably have a fiber length of about 48mm to 76mm and a tensile strength of about 3g/De to 4 g/De.

The low melting point polyethylene terephthalate fiber may suitably have a fiber length of about 48mm to 76mm and a tensile strength of about 3g/De to 4 g/De.

In forming each of the first and second nonwoven layers, each of the first and second nonwoven layers may be formed by repeatedly laminating a web into a multilayer structure of three to five layers.

In the process of producing the needle punched nonwoven, the needle punched nonwoven may suitably have about 600g/m²To 1,500g/m²Weight per unit area of (c).

The number of needle-punching in the process of producing the needle-punched nonwoven may suitably be about 20 to 80 punches/cm²。

A vehicle including the undercover described herein is also provided.

Other aspects and preferred embodiments of the invention are discussed below.

Drawings

The above and other features of this invention will be described in detail below with reference to certain exemplary embodiments thereof as illustrated in the accompanying drawings, which are given by way of illustration only, and thus are not limiting of the invention, wherein:

FIG. 1 is a cross-sectional view illustrating an exemplary needle punched nonwoven for an exemplary under cover of a vehicle according to an exemplary embodiment of the present invention; and

fig. 2 shows a structure in which exemplary webs of the needle-punched nonwoven according to the present invention are randomly arranged in horizontal and vertical directions.

Detailed Description

The above objects, and other objects, features and advantages of the present invention will be clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the present invention is not limited to these embodiments, and may be embodied in various forms. The embodiments are proposed only to provide a comprehensive and complete understanding of the disclosed context and to fully inform those skilled in the art of the technical idea of the present invention.

Like numbers refer to like elements throughout the description of the figures. In the drawings, the size of structures is exaggerated for clarity. It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be construed as limited by these terms, which are used only to distinguish one element from another. For example, a "first" element may be termed a "second" element, and, similarly, a "second" element may be termed a "first" element, within the scope defined by the present invention. The singular is intended to include the plural unless the context clearly dictates otherwise.

It will be further understood that the terms comprises and/or comprising, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. In addition, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements may also be present. It will also be understood that when an element such as a layer, film, region, or substrate is referred to as being "under" another element, it can be directly under the other element or intervening elements may also be present.

Unless the context clearly dictates otherwise, all numbers, numbers and/or expressions referring to ingredients, reaction conditions, polymer compositions and amounts of mixtures used in the specification are approximate values, which reflect the various uncertainties inherently occurring in measurements other than those obtained when such numbers are obtained. For this reason, it is to be understood that in all instances, all numbers, and/or expressions referring to the term "about" are intended to mean deviations in the terms used in this specification for ingredients, reaction conditions, polymer compositions, and amounts of mixtures, unless the context clearly dictates otherwise, or that from the context, the terms used in the specification for ingredients, reaction conditions, polymer compositions, and amounts of mixtures, as used herein, are approximations that reflect various uncertainties.

It should be understood that the term "vehicle" or "vehicular" or other similar terms as used herein generally includes motor vehicles such as passenger automobiles including Sport Utility Vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from non-petrochemical energy sources). As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as both gasoline-powered and electric-powered vehicles.

In addition, unless otherwise limited, when numerical ranges are disclosed in the specification, the ranges are continuous and include all numbers from the minimum to the maximum (including the maximum in each range). Further, unless otherwise defined, when a range refers to an integer, it includes all integers from the minimum to the maximum (including the maximum within the range).

Throughout the specification, hereinafter, the first polyethylene terephthalate (110 in fig. 2) is referred to as "regular PET", "first PET", or "PET", and the low-melting polyethylene terephthalate (120 in fig. 2) is referred to as "low-melting PET".

In particular, the terms "conventional PET", "first PET" or "PET" as used herein refer to unmodified polyethylene terephthalate having a melting point generally in the range of about 230 ℃ to 280 ℃, or in particular in the range of about 240 ℃ to 270 ℃, or in the range of about 250 ℃ to 260 ℃. As used herein, the term "low melting polyethylene terephthalate" or "low melting PET" refers to, for example, polyethylene terephthalate that has been modified by introducing a different monomer (e.g., cyclohexane dimethanol) in place of ethylene glycol monomers in the polymer chain to interfere with crystallization of the PET and lower its melting temperature (melting point or "m.p."). The melting point of the preferred low melting PET may be in the range of about 90 ℃ to 200 ℃, in the range of about 100 ℃ to 190 ℃, or particularly in the range of about 105 ℃ to 180 ℃.

Hereinafter, various exemplary embodiments of the present invention will be described in more detail.

The under cover material for a vehicle according to an exemplary embodiment of the present invention may include a single PET material, instead of using reinforcing fibers having high rigidity, such as carbon fibers and glass fibers, which are generally used for the under cover, but improving rigidity and elasticity by adjusting strength, content, and fiber arrangement of the fibers to an optimal range.

The under cover for a vehicle may secure mechanical strength by using a first felt layer and a second felt layer including conventional PET fibers and low-melting PET fibers, both having improved tensile strength. In addition, by improving the internal bonding structure of the felt layer, strain (deformation) due to load can be minimized, so that the weight of the component can be reduced, and durability can be improved.

In addition, the first and second nonwoven layers including the first and second felt layers may be needle-punched, and the number of needle-punching times may be minimized, thereby optimizing the fiber arrangement of the conventional PET fibers and the low melting point PET fibers and improving the bonding strength and elasticity between the fibers. In addition, since the under cover for a vehicle may contain only PET fibers and not contain any glass fibers, harmlessness and on-line workability may be ensured, and there is an advantage in that PET may be easily recycled.

A bottom cover for a vehicle includes a needle-punched nonwoven formed by needle-punching a first nonwoven layer including a first felt layer and a second nonwoven layer including a second felt layer formed on the first nonwoven layer. Each of the first and second felt layers may suitably comprise a fibrous web comprising conventional PET fibers in an amount of from about 1 to 40 weight percent and low melt PET fibers in an amount of from about 60 to 99 weight percent, based on the total weight of the fibrous web.

Fig. 1 is a cross-sectional view of an exemplary needle punched nonwoven, which is exemplary for use in a bottom cover of a vehicle, according to an exemplary embodiment of the present invention. As shown in fig. 1, the needle punched nonwoven includes a first nonwoven layer 150 and a second nonwoven layer 160 formed on the first nonwoven layer 150. Each of the first and second nonwoven layers 150 and 160 may include a first felt layer 130 and a second felt layer 140, the first felt layer 130 and the second felt layer 140 being laminated in a multi-layer structure of two or three layers. When the first and second felt layers are formed to have a multi-layer structure having more than three layers, the horizontal arrangement of the fibers in the felt layers may be deteriorated, and thus the strength may be decreased.

The first and second nonwoven layers may be webs in which the fibers of the first and second felt layers are randomly mixed in a horizontal and vertical arrangement. Both the first and second nonwoven layers may comprise a web of fibers, wherein the conventional PET fibers (e.g., 110 in fig. 2) and the low melt PET fibers (e.g., 120 in fig. 2) in the first and second felt layers are aligned horizontally by carding, and the horizontal alignment and the vertical alignment may be randomly mixed by needling.

That is, when the first and second nonwoven layers, which are horizontally aligned, are combined by needling, the needling of the nonwovens minimizes the physical intermingling of the fibers caused by the needling. Fig. 2 is a cross-sectional view showing an exemplary structure in which exemplary fibers of an exemplary needle-punched nonwoven are randomly arranged in both horizontal and vertical directions. As shown in fig. 2, the needle punched nonwoven has the following advantages: when the fibers are aligned in the horizontal and vertical directions (as shown in fig. 2), the material deformation due to the load is small, and the direction-dependent strength difference is small.

The first nonwoven layer and the second nonwoven layer may each have about 300g/m²To 750g/m²Weight per unit area of (c). When the basis weight of the first nonwoven layer and the second nonwoven layer is less than about 300g/m²In time, productivity may be deteriorated and cost competitiveness may be consequently degraded. In another aspect, the basis weight of the first nonwoven layer and the second nonwoven layer is greater than about 750g/m²When the production rate is improved, the physical properties may be less than desired. Preferably, the weight per unit area may be about 360g/m²To 650g/m²。

The first and second felt layers comprise a web comprising, based on the total weight of the web: conventional PET fibers in an amount of about 1 to 40 wt% and low-melting PET fibers in an amount of about 60 to 99 wt%.

The first and second felt layers may be formed by repeating the lamination to form a multilayer structure of three to five layers. The weight per unit area of about 40g/m can be produced by blending conventional PET fibers with low melting PET fibers and then carding²To 50g/m²The fiber web of (1).

In addition, the fiber net is laminated into a multilayer of three to five layersStructure, therefore, fibers of conventional PET fibers and low melting point PET fibers can be horizontally aligned to produce a lightweight nonwoven. In the present invention, a weight per unit area of about 40g/m is formed by carding and then cross-folding a plurality of times²To 50g/m²And the first felt layer and the second felt layer may be formed into a multilayer structure by repeatedly laminating the formed webs.

Conventional PET fibers may have excellent heat resistance and may impart form stability to the felt. Conventional PET fibers may have a melting point of about 240 ℃ to 270 ℃, a fiber length of about 48mm to 76mm, and a tensile strength of about 3g/De to 4 g/De.

The low melting point PET fiber can improve the rigidity of the mat due to its excellent low temperature adhesion. In particular, the low-melting PET fiber may include a sheath layer including a PET resin (1) modified to have a low melting point and improved adhesion in an amount of about 20 to 50 wt% and a core layer including a (conventional) PET resin (2) in an amount of about 50 to 80 wt%. The PET resin (1) modified to have a low melting point and improved adhesion may have a melting point of about 105 ℃ to 180 ℃, and the conventional PET resin may have a melting point of about 240 ℃ to 270 ℃. When the content of the low melting point PET resin is less than about 20 wt%, adhesion unevenness may occur, and when the content of the low melting point PET resin is more than about 50 wt%, excessive thermal deformation and strength deterioration may occur.

When the content of the low melting point PET fiber is less than about 60% by weight, the strength of the mat may be deteriorated. On the other hand, when the content of the low melting point PET fiber is more than about 99% by weight, the rigidity of the mat may be improved, but when it exceeds a certain level, the material may be transformed into a brittle material, which is brittle, and the strength may be deteriorated. The low melting point PET fiber may have a melting point of about 105 to 180 ℃, a fiber length of about 48 to 76mm, and a tensile strength of about 3 to 4 g/De. When the melting point of the low-melting PET fiber is less than about 105 ℃, the heat resistance durability may be deteriorated. On the other hand, when the melting point is more than about 180 ℃, moldability may be deteriorated.

In particular, when the tensile strength of the conventional PET fiber and the low melting point PET fiber is less than about 3g/De, the strength of the fiber may be weakened and the bending rigidity and the bending modulus may be significantly reduced. On the other hand, when the tensile strength of the conventional PET fiber and the low melting point PET fiber is more than about 4g/De, the physical properties may be deteriorated due to poor (poor) mixing of the raw materials. Preferably, the tensile strength may be about 3.2g/De to 3.7 g/De.

The needle punched nonwoven may have a weight of about 600g/m²To 1,500g/m²Weight per unit area of (c). When the weight per unit area of the needled nonwoven is less than about 600g/m²When used, the strength may be insufficient for application to a wheel cover or under cover. On the other hand, when the weight per unit area of the needled nonwoven is greater than about 1,500g/cm²When it is used, the cost competitiveness may not be sufficient for the wheel house or the under cover, and the weight reduction of the vehicle may be suppressed. Preferably, the needle punched nonwoven may have about 1,100g/m²To 1,300g/m²Weight per unit area of (c).

The needling count of the needled nonwoven may be from about 20 to 80 punches/cm². When the number of times of needling is less than about 20 punches/cm²When this occurs, it may be difficult to properly produce a needled nonwoven due to insufficient bonding of the card web. On the other hand, when the number of needling is more than about 80 punches/cm²When the stress is applied to the material, the alignment of the fibers is improved in the vertical direction, and the amount of strain applied to the material due to the load may be increased. The needle punched nonwoven can minimize the number of times the needle punching is performed on the first nonwoven layer and the second nonwoven layer, thereby reducing material deformation (strain) due to load, compared to the conventional method.

In another aspect of the present invention, there is provided a method of manufacturing a undercover for a vehicle, the method including: providing (e.g., making) PET fibers having a melting point of about 240 ℃ to 270 ℃ and low-melting PET fibers having a melting point of about 105 ℃ to 180 ℃; forming a web by carding conventional PET fibers in an amount of about 1 to 40 wt% and low-melting PET fibers in an amount of about 60 to 99 wt%, based on the total weight of the web; forming each of the first and second felt layers by bonding and hot pressing the fibrous webs; each of the first nonwoven layer and the second nonwoven layer is formed by laminating a first felt layer and a second felt layer into two to three layers, and the needle-punched nonwoven is produced by laminating a second nonwoven layer on the first nonwoven layer and then performing needle-punching.

In the process of preparing the conventional PET fiber and the low melting point PET fiber, the conventional PET fiber may be produced through a spinning, drawing and crimping process, so that the conventional PET fiber may have a fiber length of about 48 to 76mm and a tensile strength of about 3 to 4 g/De. In the same manner as described above, the low melting point PET fiber may be produced such that the low melting point PET fiber has a fiber length of about 48 to 72mm and a tensile strength of about 3 to 4g/De

In forming the first and second felt layers, the web may be laminated into a three to five layer multilayer structure to form the first and second nonwoven layers.

In the process of producing the needle punched nonwoven, the needle punched nonwoven may have about 720g/m²To 1,200g/m²Weight per unit area of (c).

In the production of the needle-punched nonwoven, the needle-punching may be performed by vertically moving a needle plate equipped with thousands of needles, wherein the number of times of needle-punching may be about 20 punches/cm²To 80 thorn/cm²。

Hereinafter, the present invention will be described in more detail with reference to examples. However, the following examples should not be construed as limiting the scope of the invention.