Easily recyclable polyester-based structure for vehicle interior parts

Abstract

The present invention relates to a polyester-based structure for vehicle interior parts, the polyester-based structure improving recycling efficiency due to being based on polyester fibers, and having excellent moldability and rigidity due to being composed of a single material. The polyester-based structure according to the present invention comprises: a first scrim layer containing both a first polyester fiber and a second polyester fiber or just the second polyester fiber; a core layer positioned on the lower surface of the first scrim layer and containing a third polyester fiber and a fourth polyester fiber; and a second scrim layer positioned on the lower surface of the core layer and containing both a fifth polyester fiber and a sixth polyester fiber or just the sixth polyester fiber.

Description

Polyester-based structural material for easily recyclable vehicle interior parts

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 2024-0108801, filed August 14, 2024, and Korean Patent Application No. 2025-0105106, filed July 31, 2025, the contents of which are incorporated herein by reference in their entirety.

[0003] The present invention relates to a polyester-based structure for vehicle interior parts that is easy to recycle.

[0004] Recently, interest in environmental friendliness has grown due to the EU's End-of-Life Vehicles (ELV) regulations. To address this, the use of recycled plastics and the development of recyclable products are required.

[0005] In particular, PP (Polypropylene) accounts for the largest proportion of plastics used in automobiles, at approximately 32%, and it is not easy to recycle because PP is reinforced with GF (Glass fiber) and MF (Mineral filler).

[0006] In comparison, PET (Polyethylene terephthalate) material is used in the form of fabrics and non-woven fabrics and is relatively easy to recycle, so the automobile industry has recently attempted to increase the recycled content by using PET material.

[0007] Additionally, there are attempts to expand the application of parts made from recycled raw materials utilizing scrapped vehicle parts to implement a closed-loop system by manufacturing single-material-based parts that are easy to dismantle and recycle.

[0008] Currently, most materials for vehicle interior components are semi-rigid PU foam-based boards (hereinafter referred to as PU boards), but they have a multilayer structure made of different materials, which makes them difficult to recycle.

[0009] In addition, the PPGF (Polypropylene + Glass fiber) based LWRT (Low weight reinforced thermoplastics) board (hereinafter referred to as PPGF board) product currently used in some vehicle models has problems such as a deterioration of the working environment due to scattering of glass fibers and unevenness of the surface after product production. In addition, the PPGF board also has the problem of low recyclability because it is made of different materials.

[0010] The problem to be solved by the present invention is to provide a polyester-based structure for vehicle interior parts that improves recycling efficiency based on polyester fibers and has excellent formability and rigidity while being composed of a single material.

[0011] The present invention is a polyester structure comprising: a first scrim layer comprising first polyester fibers and second polyester fibers, or second polyester fibers; a core layer positioned on a lower surface of the first scrim layer and comprising third polyester fibers and fourth polyester fibers; and a second scrim layer positioned on a lower surface of the core layer and comprising fifth polyester fibers and sixth polyester fibers, or sixth polyester fibers.

[0012] In the present invention, the basis weight of the first scrim layer may be 20 to 200 g / ㎡.

[0013] In the present invention, the first scrim layer may contain more than 0 wt% and less than 30 wt% of the first polyester fiber and more than 70 wt% and less than 100 wt% of the second polyester fiber, or may be made of the second polyester fiber.

[0014] In the present invention, the first polyester fiber may be a low-melting point polyethylene terephthalate fiber, and the second polyester fiber may be a regular polyethylene terephthalate fiber.

[0015] In the present invention, the basis weight of the core layer may be 700 to 1,600 g / ㎡.

[0016] In the present invention, the core layer may include 20 to 40 wt% of the third polyester fiber and 60 to 80 wt% of the fourth polyester fiber.

[0017] In the present invention, the third polyester fiber may be a composite fiber composed of a regular polyethylene terephthalate core portion and a low-melting-point polyethylene terephthalate sheath portion, and the fourth polyester fiber may be a regular polyethylene terephthalate fiber.

[0018] In the present invention, the basis weight of the second scrim layer may be 20 to 200 g / ㎡.

[0019] In the present invention, the second scrim layer may contain more than 0 wt% and less than 30 wt% of the fifth polyester fiber and more than 70 wt% and less than 100 wt% of the sixth polyester fiber, or may be made of the sixth polyester fiber.

[0020] In the present invention, the fifth polyester fiber may be a low-melting point polyethylene terephthalate fiber, and the sixth polyester fiber may be a regular polyethylene terephthalate fiber.

[0021] In the present invention, the polyester-based structure may further include a resin layer containing a polyester resin between the first scrim layer and the core layer.

[0022] In the present invention, the basis weight of the resin layer may be 20 to 150 g / ㎡.

[0023] In the present invention, the polyester resin may have a melting point of 150 to 250°C.

[0024] In the present invention, the basis weight of the polyester structure may be 740 to 2,150 g / ㎡, and the thickness may be 2 to 6 mm.

[0025] In the present invention, the intrinsic viscosity (IV) of the polyester structure may be 0.5 to 0.75 dL / g.

[0026] In the present invention, the polyester-based structure may have a flexural strength of 16 to 50 N and a flexural modulus of 300 to 800 MPa.

[0027] In the present invention, the polyester-based structure may be used for vehicle interior parts.

[0028] The present invention uses a single material of polyethylene terephthalate, so it is easy to recycle and can prevent environmental pollution.

[0029] In addition, the present invention provides rigidity to the structure and can have shape stability after molding by having scrim layers positioned on the upper and lower portions of the core layer, respectively.

[0030] In addition, by including a composite fiber composed of a regular polyethylene terephthalate core portion and a low-melting-point polyethylene terephthalate sheath portion in the core layer, adhesiveness can be enhanced and physical properties can be improved.

[0031] Figure 1 is a drawing showing a polyester structure of the present invention.

[0032] Figure 2 is a drawing showing a polyester structure including a resin layer.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In general, the nomenclature used herein and the experimental methods described below are well known and commonly used in the art.

[0034] Additionally, when the terms “about,” “approximately,” or similar expressions such as “at least” are used in connection with a numerical value in the present invention, it is intended that a theoretical, experimental, statistical, or empirical error of ±10%, ±7%, ±5%, ±3%, ±2%, or ±1% based on that numerical value is allowed.

[0035]

[0036] Figure 1 is a drawing showing a polyester structure of the present invention.

[0037] Referring to FIG. 1, the present invention is a polyester-based structure (100) comprising: a first scrim layer (110) comprising a first polyester fiber and a second polyester fiber, or a second polyester fiber; a core layer (120) positioned on a lower surface of the first scrim layer (110) and comprising a third polyester fiber and a fourth polyester fiber; and a second scrim layer (130) positioned on a lower surface of the core layer (120) and comprising a fifth polyester fiber and a sixth polyester fiber, or a sixth polyester fiber.

[0038] In the present invention, the first scrim layer (110) including the first polyester fiber and the second polyester fiber, or the second polyester fiber, is configured to improve the formability of the structure, prevent sagging of the structure after forming, protect the appearance quality of the structure, and supplement the rigidity.

[0039] The basis weight of the first scrim layer (110) may be 20 to 200 g / ㎡, and preferably, the basis weight of the first scrim layer (110) may be 80 to 120 g / ㎡. If the basis weight of the first scrim layer (110) is less than 20 g / ㎡, the structure may sag after molding, and if it exceeds 200 g / ㎡, it is not economical due to an increase in cost.

[0040] The first scrim layer (110) may contain more than 0 wt% and less than 30 wt% of the first polyester fiber, more than 70 wt% and less than 100 wt% of the second polyester fiber, or may be composed solely of the second polyester fiber. Preferably, the first polyester fiber may contain 5 wt% to 20 wt%, and the second polyester fiber may contain 80 wt% to 95 wt%. The first polyester fiber may be a low-melting-point polyethylene terephthalate fiber, and the second polyester fiber may be a regular polyethylene terephthalate fiber.

[0041] The above mixing ratio is designed to take into account the balance between improved bonding strength and durability, and the first polyester fiber with low melting point characteristics improves the interlayer bonding strength during heat fusion, and the second polyester fiber plays a role in securing the mechanical strength and dimensional stability of the first scrim layer (110).

[0042] Each fiber can have a diameter of 5 to 15 denier, which denier range can provide sufficient surface area to maximize contact area with the core layer (120) or resin layer (140) while maintaining appropriate flexibility and strength.

[0043] The first scrim layer (110) may be in the form of a non-woven fabric, and the interlayer bonding strength with the core layer (120) or resin layer (140) may be enhanced by the interfiber entanglement structure. This structure may increase interlayer delamination resistance and improve the overall durability of the structure.

[0044] In the present invention, the core layer (120) is a layer that controls the weight and thickness of the structure and maintains the shape of the structure after molding.

[0045] The basis weight of the core layer (120) may be 700 to 1,600 g / ㎡, and preferably, the basis weight of the core layer (120) may be 800 to 1,400 g / ㎡. If the basis weight of the core layer (120) is less than 700 g / ㎡, the flexural strength of the structure may be reduced, and if it exceeds 1,600 g / ㎡, the weight of the structure may increase, and the improvement in physical properties relative to the content may be minimal.

[0046] The core layer (120) may contain 20 to 40 wt% of the third polyester fiber and 60 to 80 wt% of the fourth polyester fiber, and preferably 25 to 35 wt% of the third polyester fiber and 65 to 75 wt% of the fourth polyester fiber. If the content of the third polyester fiber is less than 20 wt%, the rigidity of the structure may be reduced, and if it exceeds 40 wt%, the rigidity may be excellent, but the heat resistance may be reduced.

[0047] Additionally, the third polyester fiber may be a composite fiber composed of a regular polyethylene terephthalate core portion and a low-melting-point polyethylene terephthalate sheath portion, and the fourth polyester fiber may be a regular polyethylene terephthalate fiber.

[0048] The above composite fiber may be composed of 40 to 60 wt% of a regular polyethylene terephthalate core and 40 to 60 wt% of a low-melting-point polyethylene terephthalate sheath. If the content of the core is less than 40 wt%, the mechanical strength of the entire fiber may decrease, so that the tensile strength and heat resistance of the scrim layer may become insufficient, and the dimensional stability due to external stress may also decrease. Conversely, if the content of the core exceeds 60 wt%, the low-melting-point resin of the sheath may be relatively insufficient, so that the bonding strength with adjacent layers may decrease during the heat-bonding process, and as a result, the interlayer delamination resistance may decrease.

[0049] The above composite fiber may have a diameter of 2 to 10 denier, and the above regular polyethylene terephthalate fiber may have a diameter of 3 to 12 denier. The melting point of the low-melting polyethylene terephthalate fiber may be 110 to 180°C.

[0050] Additionally, the core layer (120) may include a needle-punched nonwoven fabric.

[0051] In the present invention, the second scrim layer (130) including the fifth polyester fiber and the sixth polyester fiber, or the sixth polyester fiber, is configured to improve the formability of the structure, prevent sagging of the structure after forming, protect the appearance quality of the structure, and supplement the rigidity.

[0052] The basis weight of the second scrim layer (130) may be 20 to 200 g / ㎡, and preferably, the basis weight of the second scrim layer (130) may be 80 to 120 g / ㎡. If the basis weight of the second scrim layer (130) is less than 20 g / ㎡, the structure may sag after molding, and if it exceeds 200 g / ㎡, it is not economical due to an increase in cost.

[0053] The second scrim layer (130) may contain 0 wt% to 30 wt% of the fifth polyester fiber, 70 wt% to 100 wt% of the sixth polyester fiber, or may be composed solely of the sixth polyester fiber. Preferably, the fifth polyester fiber may contain 5 wt% to 20 wt%, and the sixth polyester fiber may contain 80 wt% to 95 wt%. The fifth polyester fiber may be a low-melting-point polyethylene terephthalate fiber, and the sixth polyester fiber may be a regular polyethylene terephthalate fiber.

[0054] The above mixing ratio is designed to take into account the balance between improved bonding strength and durability. The fifth polyester fiber with low melting point characteristics improves the interlayer bonding strength during heat fusion, and the sixth polyester fiber plays a role in securing the mechanical strength and dimensional stability of the scrim layer.

[0055] Each fiber can have a diameter of 5 to 15 denier, which denier range provides sufficient surface area to maximize contact area with the core layer (120) while maintaining appropriate flexibility and strength.

[0056] The second scrim layer (130) may be in the form of a non-woven fabric, and the interlayer bonding strength with the core layer (120) may be enhanced by the interfiber entanglement structure. This structure may increase interlayer delamination resistance and improve the overall durability of the structure.

[0057] Figure 2 is a drawing showing a polyester structure including a resin layer.

[0058] Referring to FIG. 2, the polyester-based structure (100) may further include a resin layer (140) containing a polyester resin between the first scrim layer (110) and the core layer (120).

[0059] In the present invention, the resin layer (140) is a layer for improving the physical properties of the structure, such as flexural strength and tensile strength.

[0060] The basis weight of the above resin layer (140) may be 20 to 150 g / ㎡, and preferably, the basis weight of the above resin layer (140) may be 30 to 100 g / ㎡. If the basis weight of the above resin layer (140) is less than 20 g / ㎡, the flexural strength of the structure may be reduced, and if it exceeds 150 g / ㎡, the cost increases, making it uneconomical, the improvement in physical properties relative to the content is minimal, and the weight of the structure may increase.

[0061] The polyester resin may be a polyethylene terephthalate resin, and the hardness of the polyester resin may be 50 to 80 Shore D. The polyester resin may be in powder form, and after being applied to the surface of the core layer in powder form, it may take the form of a film by heat.

[0062] The intrinsic viscosity (IV) of the polyester-based structure according to the present invention may be 0.5 to 0.75 dL / g, preferably 0.55 to 0.70 dL / g. The intrinsic viscosity may be measured using an Ubbelohde viscometer at 25°C using a mixed solvent of phenol / tetrachloroethane (60:40 weight ratio).

[0063] When the intrinsic viscosity is less than 0.5 dL / g, the molecular weight is low, which may reduce the mechanical strength and heat resistance of the structure, and problems such as deformation or delamination may occur during the heat-melting process. On the other hand, when the intrinsic viscosity exceeds 0.75 dL / g, the molecular weight increases excessively, which reduces processability, increases the melting temperature, which may reduce process energy efficiency, and may also reduce bonding with the resin layer.

[0064] In the present invention, the polyester structure (100) may have a flexural strength of 16 to 50 N and a flexural modulus of 300 to 800 MPa.

[0065] In addition, the above flexural strength and flexural modulus can be obtained by applying a load to a 50 mm x 150 mm test piece at a rate of 5 mm / min in accordance with ISO D790 and measuring the ratio of the applied stress to the maximum load and the resulting deformation.

[0066] If the flexural strength is less than 16 N, the mechanical support capacity of the structure may be insufficient, which may cause cracking, breakage, or sagging under external impact or repeated stress. In particular, when applied to a laminated structure, delamination may occur at the bonding interface with the first (110), second scrim layer (130), or resin layer (140). Conversely, if the flexural strength exceeds 50 N, the material may become excessively brittle, making it vulnerable to impact and potentially causing local destruction.

[0067] Furthermore, if the flexural modulus is less than 300 MPa, the material's elastic recovery capacity is insufficient, making it prone to permanent deformation by external forces, and reducing the structural resilience and durability. Conversely, if the flexural modulus exceeds 800 MPa, the material becomes excessively rigid, reducing its toughness. This increases the likelihood of brittle fracture under bending or impact, and cracks or damage may occur due to the compressive force during the thermal bonding process.

[0068] Additionally, in the present invention, the thickness of the polyester-based structure (100) may be 2 mm or more and 6 mm or less.

[0069] The above polyester structure (100) can be used for a vehicle interior part, and the vehicle interior part can be a member that is placed in the interior space of a vehicle and performs functions such as interior finishing, sound absorption, dustproofing, and insulation.

[0070] For example, the vehicle interior component may be a headliner, a door trim, a pillar garnish, a sun visor, a roof side rail cover, a rear package tray, a trunk cover, or a floor mat, and preferably, the structure is applied to the headliner.

[0071] Through such application, the polyester structure (100) of the present invention can contribute to reducing the weight of vehicle interior parts, ensuring impact resistance, and maintaining excellent exterior quality.

[0072] Hereinafter, the composition and effects of the present invention will be described in more detail through examples. These examples are intended solely to illustrate the present invention, and the scope of the present invention is not limited by these examples.

[0073]

[0074] The compositions used in the examples and comparative examples are as follows.

[0075]

[0076] First polyester fiber: low-melting polyethylene terephthalate fiber with a diameter of 8.5 denier

[0077] Secondary polyester fiber: Regular polyethylene terephthalate fiber with a diameter of 8.5 denier

[0078] Third polyester fiber: A composite fiber having a diameter of 4 denier and composed of 50% by weight of a regular polyethylene terephthalate core and 50% by weight of a low-melting polyethylene terephthalate sheath.

[0079] 4th polyester fiber: regular polyethylene terephthalate fiber with a diameter of 6 denier

[0080] Fifth polyester fiber: low-melting polyethylene terephthalate fiber with a diameter of 8.5 denier

[0081] 6th polyester fiber: regular polyethylene terephthalate fiber with a diameter of 8.5 denier

[0082] First scrim layer: Nonwoven fabric composed of 15 wt% of first polyester fibers and 85 wt% of second polyester fibers

[0083] Core layer: Needle-punched nonwoven fabric composed of 30 wt% of third polyester fiber and 70 wt% of fourth polyester fiber

[0084] Second scrim layer: Nonwoven fabric composed of 15 wt% of fifth polyester fiber and 85 wt% of sixth polyester fiber

[0085] Polyester resin: Polyethylene terephthalate powder with a Shore D of 50 to 80 and a melting point of approximately 200 to 220°C.

[0086]

[0087] Example 1

[0088] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0089]

[0090] Example 2

[0091] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 80 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0092]

[0093] Example 3

[0094] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 120 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0095]

[0096] Example 4

[0097] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 800 g / ㎡, and 100 g / ㎡, respectively.

[0098]

[0099] Example 5

[0100] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 1400 g / ㎡, and 100 g / ㎡, respectively.

[0101]

[0102] Example 6

[0103] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 1200 g / ㎡, and 80 g / ㎡, respectively.

[0104]

[0105] Example 7

[0106] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 1200 g / ㎡, and 120 g / ㎡, respectively.

[0107]

[0108] Example 8

[0109] A core layer made of needle-punched nonwoven fabric is prepared. A polyester resin is applied to one side of the core layer, and the resin layer is manufactured by melt-extruding at 210°C. A first scrim layer is positioned on the upper side of the resin layer, a second scrim layer is positioned on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the resin layer, the core layer, and the second scrim layer are 100 g / ㎡, 50 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0110]

[0111] Example 9

[0112] A core layer made of needle-punched nonwoven fabric is prepared. A polyester resin is applied to one side of the core layer, and the resin layer is manufactured by melt-extruding at 210°C. A first scrim layer is positioned on the upper side of the resin layer, a second scrim layer is positioned on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the resin layer, the core layer, and the second scrim layer are 100 g / ㎡, 30 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0113]

[0114] Example 10

[0115] A core layer made of needle-punched nonwoven fabric is prepared. A polyester resin is applied to one surface of the core layer, and the resin layer is manufactured by melt-extruding at 210°C. A first scrim layer is positioned on the upper surface of the resin layer, a second scrim layer is positioned on the other surface of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the resin layer, the core layer, and the second scrim layer are 100 g / m2, 100 g / m2, 1200 g / m2, and 100 g / m2, respectively.

[0116]

[0117] Comparative Example 1

[0118] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 10 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0119]

[0120] Comparative Example 2

[0121] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 220 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0122]

[0123] Comparative Example 3

[0124] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 600 g / ㎡, and 100 g / ㎡, respectively.

[0125]

[0126] Comparative Example 4

[0127] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 1800 g / ㎡, and 100 g / ㎡, respectively.

[0128]

[0129] Comparative Example 5

[0130] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 1200 g / ㎡, and 10 g / ㎡, respectively.

[0131]

[0132] Comparative Example 6

[0133] A core layer made of needle-punched nonwoven fabric is prepared. A first scrim layer is placed on one side of the core layer, a second scrim layer is placed on the other side of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the core layer, and the second scrim layer are 100 g / ㎡, 1200 g / ㎡, and 220 g / ㎡, respectively.

[0134]

[0135] Comparative Example 7

[0136] A core layer made of needle-punched nonwoven fabric is prepared. A polyester resin is applied to one surface of the core layer, and the resin layer is manufactured by melt-extruding at 210°C. A first scrim layer is positioned on the upper surface of the resin layer, a second scrim layer is positioned on the other surface of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the resin layer, the core layer, and the second scrim layer are 100 g / ㎡, 10 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0137]

[0138] Comparative Example 8

[0139] A core layer made of needle-punched nonwoven fabric is prepared. A polyester resin is applied to one surface of the core layer, and the resin layer is manufactured by melt-extruding at 210°C. A first scrim layer is positioned on the upper surface of the resin layer, a second scrim layer is positioned on the other surface of the core layer, and then heat is applied to 250°C to manufacture a structure. The basis weights of the first scrim layer, the resin layer, the core layer, and the second scrim layer are 100 g / ㎡, 180 g / ㎡, 1200 g / ㎡, and 100 g / ㎡, respectively.

[0140]

[0141] Comparative Example 9

[0142] A glass mat and a polyethylene terephthalate nonwoven fabric are placed on each side of a polyurethane foam sheet. At this time, a urethane-based adhesive is applied between the polyurethane foam sheet and the glass mat to attach them, and a polyolefin-based hot melt film is attached between the glass mat and the polyethylene terephthalate nonwoven fabric to manufacture a structure.

[0143]

[0144] In Examples 1 to 10 and Comparative Examples 1 to 8, the basis weights of the first scrim layer, the resin layer, the core layer, and the second scrim layer are as shown in Table 1 below.

[0145]

[0146] Classification 1 scrim layer (g / m) 2 )Resin layer (g / m) 2 )Core layer (g / m) 2 )Second scrim layer (g / m) 2)Embodiment 1 100-1200 100Embodiment 2 80-1200 100Embodiment 3 120-1200 100Embodiment 4 100-800 100Embodiment 5 100-1400 100Embodiment 6 100-1200 80Embodiment 7 100-1200 120Embodiment 8 100 50 1200 100Embodiment 9 100 30 1200 100 Example 101001001200100Comparative Example 110-1200100Comparative Example 2220-1200100Comparative Example 3100-600100Comparative Example 4100-1800100Comparative Example 5100-120010Comparative Example 6100-1200220Comparative Example 7100101200100Comparative Example 81001801200100

[0147] Experimental Example 1 In order to compare the effect according to the basis weight of the first scrim layer, the flexural strength and flexural modulus of the structures manufactured in Examples 1 to 3 and Comparative Examples 1 and 2 were measured using the following measurement methods, and are shown in Table 2 below.

[0148] [measurement method]

[0149] Flexural strength and flexural modulus: According to ISO D790, a load is applied to a 50 mm x 150 mm test piece at a rate of 5 mm / min, and the ratio of applied stress to the maximum load and the resulting deformation is measured.

[0150] Shape stability: After heating the specimen in an oven, the heated specimen was removed and inserted into a mold shaped like an automotive interior part, and the mold was closed to perform cold forming. Forming was performed at room temperature under constant pressure. After forming was complete, the specimen was removed from the mold, and the overall shape of the specimen and the degree of transfer of the embossed and debossed shapes formed on the specimen were visually evaluated. If the shape of the specimen was maintained without deformation and the embossed and debossed shapes were clearly transferred, it was evaluated as "good." If the shape of the specimen was deformed or the shape transfer was incomplete, it was evaluated as "bad."

[0151]

[0152] Classification Flexural strength (N) (MD / TD) Flexural modulus (MPa) (MD / TD) Shape stability Example 138 / 40 (MD / TD) 591 / 550 Good Example 238 / 346 09 / 490 Good Example 341 / 396 62 / 541 Good Comparative Example 138 / 386 08 / 527 Poor Comparative Example 259 / 578 03 / 793 Poor

[0153] Referring to Table 2 above, when the basis weight of the first scrim layer was 80 g / ㎡ (Example 2), 100 g / ㎡ (Example 1), and 120 g / ㎡ (Example 3), all exhibited good dimensional stability, and the flexural strength and flexural modulus were stably maintained in the ranges of 34 to 41 N and 490 to 662 MPa, respectively. On the other hand, in Comparative Example 1, where the basis weight of the first scrim layer was excessively low at 10 g / ㎡, the flexural strength and flexural modulus were maintained at a certain level, but the dimensional stability after molding was poor.

[0154] In addition, in Comparative Example 2, where the basis weight of the first scrim layer was excessively high at 220 g / ㎡, the flexural strength and flexural modulus increased to 59 N and 803 MPa, respectively, but the dimensional stability after molding was rather poor due to the excessive rigidity of the material.

[0155]

[0156] Experimental Example 2

[0157] In order to compare the effect according to the basis weight of the core layer, the flexural strength and flexural modulus of the structures manufactured in Examples 1, 4, and 5 and Comparative Examples 3 and 4 were measured using the following measurement methods, and are shown in Table 3 below.

[0158]

[0159] [measurement method]

[0160] Flexural strength and flexural modulus: According to ISO D790, a load is applied to a 50 mm x 150 mm test piece at a rate of 5 mm / min, and the ratio of applied stress to the maximum load and the resulting deformation is measured.

[0161] Shape stability: After heating the specimen in an oven, the heated specimen was removed and inserted into a mold shaped like an automotive interior part, and the mold was closed to perform cold forming. Forming was performed at room temperature under constant pressure. After forming was complete, the specimen was removed from the mold, and the overall shape of the specimen and the degree of transfer of the embossed and debossed shapes formed on the specimen were visually evaluated. If the shape of the specimen was maintained without deformation and the embossed and debossed shapes were clearly transferred, it was evaluated as "good." If the shape of the specimen was deformed or the shape transfer was incomplete, it was evaluated as "bad."

[0162]

[0163] Classification Flexural strength (N) Flexural modulus (MPa) Shape stability Example 138 / 40 (MD / TD) 591 / 550 Good Example 421 / 186 04 / 493 Good Example 549 / 49 596 / 605 Good Comparative example 314 / 126 16 / 531 Good Comparative example 453 / 57 602 / 611 Good

[0164] Referring to Table 3 above, when the basis weight of the core layer was 800 g / ㎡ (Example 4), 1200 g / ㎡ (Example 1), and 1400 g / ㎡ (Example 5), the flexural strength was maintained in the range of 21 to 49 N and the flexural modulus was 493 to 605 MPa, and the dimensional stability after molding was also confirmed to be good. On the other hand, Comparative Example 3, in which the basis weight of the core layer was low at 600 g / ㎡, showed a flexural strength of 14 N and an elastic modulus of 616 MPa, and the strength value was less than 16 N, which is the preferable lower limit of the invention, indicating that the structural support capacity was insufficient.

[0165] On the other hand, Comparative Example 4, which had an excessively high basis weight of 1800 g / ㎡, had an increased flexural strength of 53 to 57 N, but had an increased impact vulnerability due to excessive rigidity.

[0166]

[0167] Experimental Example 3

[0168] In order to compare the effect according to the basis weight of the second scrim layer, the flexural strength and flexural modulus of the structures manufactured in Examples 1, 6, and 7 and Comparative Examples 5 and 6 were measured using the following measurement method, and the results are shown in Table 4 below.

[0169] [measurement method]

[0170] Flexural strength and flexural modulus: According to ISO D790, a load is applied to a 50 mm x 150 mm test piece at a rate of 5 mm / min, and the ratio of applied stress to the maximum load and the resulting deformation is measured.

[0171] Shape stability: After heating the specimen in an oven, the heated specimen was removed and inserted into a mold shaped like an automotive interior part, and the mold was closed to perform cold forming. Forming was performed at room temperature under constant pressure. After forming was complete, the specimen was removed from the mold, and the overall shape of the specimen and the degree of transfer of the embossed and debossed shapes formed on the specimen were visually evaluated. If the shape of the specimen was maintained without deformation and the embossed and debossed shapes were clearly transferred, it was evaluated as "good." If the shape of the specimen was deformed or the shape transfer was incomplete, it was evaluated as "bad."

[0172]

[0173] Classification Flexural strength (N) Flexural modulus (MPa) Shape stability Example 138 / 40 (MD / TD) 591 / 550 (MD / TD) Good Example 635 / 33601 / 512 Good Example 744 / 38590 / 496 Good Comparative Example 537 / 38610 / 581 Poor Comparative Example 662 / 48821 / 780 Poor

[0174] Referring to Table 4 above, when the basis weight of the second scrim layer was 80 g / ㎡ (Example 6), 100 g / ㎡ (Example 1), and 120 g / ㎡ (Example 7), the flexural strength was 33 to 44 N, the elastic modulus was 496 to 601 MPa, and the dimensional stability after molding was also well maintained. On the other hand, in Comparative Example 5, where the basis weight was excessively low at 10 g / ㎡, the dimensional stability was poor, and it is believed that this is because the supporting force of the scrim layer was insufficient, resulting in sagging or deformation of the structure after molding.

[0175] In addition, in Comparative Example 6, which was excessively thick at 220 g / ㎡, the flexural strength and elastic modulus increased rapidly to 62 N and 821 MPa, respectively, but the formability was reduced due to the stiffening of the material, and vulnerability to external impact and reduced dimensional stability were confirmed.

[0176]

[0177] Experimental Example 4

[0178] In order to compare the effect according to the basis weight of the resin layer, the flexural strength and flexural modulus of the structures manufactured in Examples 8 to 10 and Comparative Examples 7 and 8 were measured using the following measurement method, and the results are shown in Table 5 below.

[0179] [measurement method]

[0180] Flexural strength and flexural modulus: According to ISO D790, a load is applied to a 50 mm x 150 mm test piece at a rate of 5 mm / min, and the ratio of applied stress to the maximum load and the resulting deformation is measured.

[0181] Shape stability: After heating the specimen in an oven, the heated specimen was removed and inserted into a mold shaped like an automotive interior part, and the mold was closed to perform cold forming. Forming was performed at room temperature under constant pressure. After forming was complete, the specimen was removed from the mold, and the overall shape of the specimen and the degree of transfer of the embossed and debossed shapes formed on the specimen were visually evaluated. If the shape of the specimen was maintained without deformation and the embossed and debossed shapes were clearly transferred, it was evaluated as "good." If the shape of the specimen was deformed or the shape transfer was incomplete, it was evaluated as "bad."

[0182]

[0183] Classification Flexural strength (N) Flexural modulus (MPa) Shape stability Example 138 / 40 (MD / TD) 591 / 550 (MD / TD) Good Example 844 / 46 693 / 605 Good Example 943 / 44 690 / 612 Good Example 1049 / 48 700 / 673 Good Comparative Example 740 / 40 601 / 550 Good Comparative Example 866 / 62 774 / 721 Poor

[0184] Referring to Table 5 above, in Examples 8 to 10 where the basis weight of the resin layer was 30 to 100 g / ㎡, the flexural strength was 43 to 49 N and the flexural modulus was 612 to 700 MPa, confirming that the introduction of the resin layer had a positive effect on improving the mechanical performance of the structure. In addition, the dimensional stability was also well maintained in all examples. On the other hand, Comparative Example 7 where the basis weight was too low at 10 g / ㎡ showed a minimal performance improvement effect, and only showed properties (40 N, 601 MPa) similar to those of Example 1. This means that when the content of the resin layer is below a certain level, the performance improvement is limited compared to the economic feasibility of the additional process.

[0185] In addition, in Comparative Example 8, where the basis weight of the resin layer was excessively high at 180 g / ㎡, the flexural strength increased to 66 N and the flexural modulus increased to 774 MPa, but the dimensional stability decreased due to over-curing of the material.

[0186]

[0187] Experimental Example 5

[0188] In order to measure the intrinsic viscosity of the structure, the intrinsic viscosity of the structures manufactured in Examples 1 to 10 and Comparative Examples 1 to 8 was measured using the following measurement method, and the results are shown in Table 6 below.

[0189] [measurement method]

[0190] Intrinsic viscosity: Measured at 25°C with an Ubbelohde viscometer using a mixed solvent of phenol / tetrachloroethane (60:40 weight ratio).

[0191]

[0192] Classification Intrinsic viscosity (IV) Example 10.640 Example 20.629 Example 30.648 Example 40.650 Example 50.617 Example 60.631 Example 70.644 Example 80.571 Example 90.587 Example 100.564 Comparative Example 10.610 Comparative Example 20.655 Comparative Example 30.663 Comparative Example 40.609 Comparative Example 50.598 Comparative Example 60.652 Comparative Example 70.588 Comparative Example 80.533

[0193] Referring to Table 6 above, for the examples, the intrinsic viscosity was measured to be in the range of 0.564 to 0.650 dL / g, which falls within the preferred range of 0.5 to 0.75 dL / g of the invention. In particular, examples 1 to 7 were evaluated to have balanced heat sealability and mechanical properties with 0.629 to 0.650 dL / g. On the other hand, comparative example 8 was measured to have an intrinsic viscosity of 0.533 dL / g, which is less than 0.55, so there is a possibility of a decrease in mechanical strength and heat resistance due to a decrease in molecular weight, and there are concerns about problems such as peeling during heat sealing.

[0194]

[0195] Experimental Example 6

[0196] In order to evaluate the recyclability of the structures manufactured in Examples 1, 8 and Comparative Example 9, the structures were crushed into recycled chips and then the recyclability was verified through a radioactivity test.

[0197]

[0198] It was confirmed that the structures according to Examples 1 and 8 did not cause truncation during radiation and had excellent workability.

[0199] On the other hand, it was confirmed that the structure according to Comparative Example 9 was made of heterogeneous composite materials such as polyethylene terephthalate, polyurethane, polyolefin, and glass fiber, and thus radiation and recycling were impossible due to the high foreign matter content.

[0200]

[0201] [Explanation of symbols]

[0202] 100: Polyester structure 110: First scrim layer

[0203] 120: Core layer 130: Second scrim layer

[0204] 140: Resin layer

[0205]

[0206] The present invention can provide a polyester-based structure for vehicle interior parts that improves recycling efficiency based on polyester fibers and has excellent formability and rigidity while being composed of a single material.

Claims

1. A first scrim layer comprising first polyester fibers and second polyester fibers, or second polyester fibers; A core layer positioned on the lower surface of the first scrim layer and including a third polyester fiber and a fourth polyester fiber; and A second scrim layer positioned on the lower surface of the core layer and comprising a fifth polyester fiber and a sixth polyester fiber, or a sixth polyester fiber; A polyester structure comprising:

2. In paragraph 1, A polyester-based structure, wherein the weight of the first scrim layer is 20 to 200 g / ㎡.

3. In paragraph 1, A polyester-based structure, wherein the first scrim layer comprises more than 0 wt% and less than 30 wt% of the first polyester fiber and more than 70 wt% and less than 100 wt% of the second polyester fiber, or is made of the second polyester fiber.

4. In paragraph 1, A polyester structure, wherein the first polyester fiber is a low-melting polyethylene terephthalate fiber, and the second polyester fiber is a regular polyethylene terephthalate fiber.

5. In paragraph 1, A polyester structure having a weight of the core layer of 700 to 1,600 g / ㎡.

6. In paragraph 1, A polyester structure, wherein the core layer comprises 20 to 40 wt% of a third polyester fiber and 60 to 80 wt% of a fourth polyester fiber.

7. In paragraph 1, A polyester structure, wherein the third polyester fiber is a composite fiber composed of a regular polyethylene terephthalate core portion and a low-melting-point polyethylene terephthalate sheath portion, and the fourth polyester fiber is a regular polyethylene terephthalate fiber.

8. In paragraph 1, A polyester structure having a basis weight of the second scrim layer of 20 to 200 g / ㎡.

9. In paragraph 1, A polyester structure, wherein the second scrim layer comprises more than 0 wt% and less than 30 wt% of the fifth polyester fiber and more than 70 wt% and less than 100 wt% of the sixth polyester fiber, or is made of the sixth polyester fiber.

10. In paragraph 1, A polyester structure, wherein the fifth polyester fiber is a low-melting point polyethylene terephthalate fiber, and the sixth polyester fiber is a regular polyethylene terephthalate fiber.

11. In paragraph 1, A polyester-based structure, wherein the polyester-based structure further comprises a resin layer containing a polyester resin between the first scrim layer and the core layer.

12. In paragraph 11, A polyester-based structure having a basis weight of the above resin layer of 20 to 150 g / ㎡.

13. In paragraph 11, The above polyester resin is a polyester-based structural body having a melting point of 150 to 250°C.

14. In paragraphs 1 and 11, A polyester structure having a basis weight of 740 to 2,150 g / ㎡ and a thickness of 2 to 6 mm.

15. In paragraphs 1 and 11, A polyester structure having an intrinsic viscosity (IV) of 0.5 to 0.75 dL / g.

16. In paragraphs 1 and 11, The above polyester-based structure has a flexural strength of 16 to 50 N and a flexural modulus of 300 to 800 MPa.

17. In paragraph 1, The above polyester-based structure is a polyester-based structure for use in vehicle interior parts.

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