Full-structure recyclable polyethylene glycol terephthalate filament felt as well as preparation method and application thereof

Abstract

The invention relates to the technical field of automobile interior and exterior composite material preparation, in particular to a full-structure recyclable polyethylene glycol terephthalate filament felt and a preparation method and application thereof. The method comprises the following steps: spinning by taking low-melting-point modified PET as a skin layer and unmodified PET as a core layer to obtain a PET filament with a skin-core structure; carrying out web forming and heat treatment to obtain a PET long fiber web; needling the PET long fiber net to obtain a PET filament felt; the PET filament felt can be used for preparing an automobile interior and exterior composite material through a mold pressing process. The full-structure recoverable PET filament felt provided by the invention is remarkably improved in the aspects of preparation process and recoverability, and an automobile interior and exterior composite material prepared from the full-structure recoverable PET filament felt also has outstanding performance in the aspects of light weight, NVH (Noise Vibration and Harshness) resistance and cost effectiveness, so that the comprehensive performance of the automobile interior and exterior composite material is favorably improved.

Description

Technical Field

[0001] The invention relates to the technical field of preparing composite materials for automobile interior and exterior decoration, and in particular to a fully-structured recyclable polyethylene terephthalate filament felt and a preparation method and application thereof. Background Art

[0002] With the development of the automobile industry, automotive interior and exterior composite materials need to have good mechanical strength, low density, recyclability, and NVH (Noise, Vibration, Harshness) and other properties to achieve the safety, environmental protection and lightweight of the car. Existing interior and exterior materials are mainly glass fiber reinforced thermoplastic resin (CN202011629759.8). Although they meet the requirements of lightweight and low cost, they lack mechanical strength and recyclability. Therefore, developing a new type of automotive interior and exterior composite material that has the advantages of lightweight and low cost, as well as good mechanical strength and recyclability, is an important issue facing current technology.

[0003] Polyethylene terephthalate (PET) is a widely used high-performance thermoplastic polyester material. Due to its excellent physical and mechanical properties, it is widely used in many fields such as fibers, films, and bottle flakes. Its application in the field of automotive interior and exterior composite materials is mainly through composite use with glass fiber (CN201410523960.6), plant fiber (CN200610047490.6) or other thermoplastic resins (CN201580023456.2). These composite materials are usually composed of reinforcing fibers and resin bonding matrix. The difference in reinforcing fibers and resin bonding matrix materials makes it difficult for these composite materials to achieve full structural recyclability. Therefore, the key to improving the recyclability of composite materials is to simultaneously achieve the functions of reinforcing fibers and bonding matrix with the same polymer, which is generally achieved by adjusting the melting point of homogeneous polymers. Prior art CN202110618306.3 discloses a method for making non-woven felt from pure PET composite long fibers, which uses 30% nano-alumina particles and PET to melt and extrude to prepare filament fibers, and achieves fiber bonding by sprinkling powder on the fiber surface. Although this material has the characteristics of partial recyclability, its powdering process is prone to problems such as uneven powder distribution and poor interface bonding between powder and fiber.

[0004] PET fiber with a skin-core structure can well achieve full structural recyclability. At the same time, since the skin layer and the core layer adopt co-extrusion spinning technology, the interface between the two is well bonded. This type of fiber has been successfully used as sanitary materials, clothing and home textiles, filter materials and textile materials, etc., and its application prospects in the automotive interior and exterior decoration industry are gradually becoming prominent. Unlike applications in the fields of sanitation and textiles, automotive interior and exterior decorations have high requirements for the mechanical properties of PET fibers, and at the same time require them to have a certain ability to resist thermal deformation. Prior art CN 202110912501.7 discloses non-woven fabrics that are easy to directly mold and process, and their production methods and uses. Its application in the automotive field mainly considers its NVH performance, without considering mechanical properties and anti-deformation ability. Prior art CN201880028591.X discloses a fluffy fiber decorative part, comprising a fiber layer composed of thermoplastic bicomponent filaments or staple fibers, and reducing the shrinkage of the fibers by adding a shrinkage reducer. However, it does not consider the impact of the fiber preparation process on the performance of the final decorative part.

[0005] In summary, the existing automotive interior and exterior composite materials technology has problems such as poor recyclability and interface bonding caused by the inconsistency between the reinforcing fibers and the bonding matrix materials. It also fails to consider the various requirements of automotive interior and exterior trims for the mechanical properties, thermal stability, NVH performance, etc. of panels and profiles. In particular, it fails to consider the impact of the preparation process of skin-core structured PET filament felt on the performance of automotive interior and exterior trim panels. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a fully recyclable polyethylene terephthalate filament felt and a preparation method and application thereof. The present invention not only significantly improves the preparation process and recyclability of PET filament felt, but the automotive interior and exterior composite materials prepared therefrom also have outstanding performance in lightweight, anti-NVH performance and cost-effectiveness, which helps to achieve comprehensive performance improvement of automotive interior and exterior composite materials.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a fully-structured recyclable polyethylene terephthalate filament felt, comprising the following steps:

[0009] 1) Spinning a polyethylene terephthalate filament having a sheath-core structure by using a low-melting-point modified polyethylene terephthalate having a melting point of 180 to 230° C. as a sheath layer and an unmodified polyethylene terephthalate having a melting point of 250 to 260° C. as a core layer;

[0010] The mass ratio of the skin layer to the core layer is 1-4:6-9;

[0011] The side wind temperature of the spinning is 15-30°C, and the drafting pressure is 0.22-0.50MPa;

[0012] Preferably, the low melting point modified polyethylene terephthalate with a melting point of 180-230° C. is TRN-3320AC produced by Teijin Ltd. of Japan.

[0013] Preferably, the brand of the unmodified polyethylene terephthalate with a melting point of 250-260° C. is any brand of commercially available polyester (fiber grade) composite spinning chips from Sinopec.

[0014] 2) forming a web of polyethylene terephthalate filaments obtained in step 1) and heat-treating the web to obtain a polyethylene terephthalate filament web;

[0015] The heat treatment temperature is 70-120°C and the treatment time is 50-100s;

[0016] 3) The polyethylene terephthalate filament web obtained in step 2) is needle-punched to obtain a polyethylene terephthalate filament felt.

[0017] Preferably, the mass ratio of the skin layer to the core layer in step 1) is 3:7;

[0018] The side wind temperature of the spinning was 24° C. and the drawing pressure was 0.25 MPa.

[0019] Preferably, the spinning step in step 1) comprises: melting the skin layer and the core layer separately to obtain melts and then mixing them to form a skin-core structure composite melt;

[0020] The obtained composite melt of the skin-core structure is cooled and formed under a double side wind with a pressure of 4 to 10 MPa and a side wind temperature of 15 to 30° C. to obtain a filament;

[0021] The obtained filaments are drawn at a drawing temperature of 30 to 40° C. and a drawing pressure of 0.22 to 0.50 MPa.

[0022] Preferably, in step 1), the polyethylene terephthalate filaments have a fineness of 3 to 6 dtex and a concentric circle diameter of 6 to 22 μm.

[0023] Preferably, the conditions for forming the web in step 2) include: forming the polyethylene terephthalate filaments into a long fiber web with a surface density of 60 to 1600 gsm under the action of tubular or slit suction air.

[0024] Preferably, the conditions for acupuncture in step 3) include: acupuncture density of 50 to 150 times / m 2 , depth is 5 to 10 mm.

[0025] The present invention also provides a polyethylene terephthalate filament felt prepared by the preparation method described in the above technical solution, wherein the polyethylene terephthalate filament felt has a surface density of 900 to 1600 gsm and a thickness of 10 to 20 mm.

[0026] The present invention also provides the use of the polyethylene terephthalate filament felt described in the above technical solution in the preparation of composite materials for automobile interior and exterior decoration.

[0027] Preferably, the application includes: subjecting the polyethylene terephthalate filament felt to steam molding to obtain a composite material for automobile interior and exterior decoration;

[0028] The steam molding conditions include: steam temperature of 140-230° C., ventilation time of 20-80 seconds, mold temperature of 140-230° C., mold closing time of 40-100 seconds, and mold pressure of 200-500 tons.

[0029] Preferably, the automobile interior and exterior composite material has a thickness of 1.5 to 3.0 mm and a gram weight of 900 to 1600 gsm.

[0030] Beneficial effects of the present invention:

[0031] 1. Preparation process: The present invention adopts a melt spinning process to prepare a single PET filament felt with a skin-core structure and a composite material thereof, wherein the skin layer adopts low melting point PET and the core layer adopts high melting point PET, and a fully recyclable PET filament is obtained by the melt spinning process, and a PET filament felt with a thickness of 10-20 mm is prepared by a needle punching process, and a composite material such as a vehicle bottom guard plate is prepared by a steam molding process. The preparation process of the present invention can efficiently and quickly realize the preparation of PET filament felt and a composite material thereof.

[0032] 2. The whole structure is recyclable: The PET filament felt of the present invention and the automotive interior and exterior composite material prepared therefrom are all recyclable, which is beneficial to environmental protection and sustainable utilization of resources. This is in sharp contrast to the problem that existing PET composite materials are non-recyclable or partially recyclable, and has significant advantages.

[0033] 3. Excellent anti-NVH performance, light weight and low cost: The PET composite material of the present invention has excellent anti-NVH performance, can reduce the noise and vibration generated during the driving of the car, and improve the driving comfort. It also has the advantages of light weight and low cost. Compared with the existing materials such as car underbody guards, fenders, and luggage compartment side trims, it can significantly reduce the weight and cost of the car and improve fuel efficiency and economy.

[0034] In general, compared with the prior art, the present invention not only has significant improvements in preparation process, recyclability and lightweight, but also has outstanding performance in anti-NVH performance and cost-effectiveness. It is an ideal composite material for automotive interior and exterior decoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments are briefly introduced below.

[0036] Figure 1 This is the cross section of the core-skin structure PET filament;

[0037] Figure 2 The process route for preparing the fully-structured recyclable PET filament felt of the present invention;

[0038] Figure 3 The utility model relates to an automobile underbody guard plate which is prepared from PET filament felt by a steam molding method. DETAILED DESCRIPTION

[0039] The present invention provides a method for preparing a fully recyclable polyethylene terephthalate filament felt, comprising the following steps:

[0040] 1) Spinning a polyethylene terephthalate filament having a sheath-core structure by using a low-melting-point modified polyethylene terephthalate having a melting point of 180 to 230° C. as a sheath layer and an unmodified polyethylene terephthalate having a melting point of 250 to 260° C. as a core layer;

[0041] The mass ratio of the skin layer to the core layer is 1-4:6-9;

[0042] The side wind temperature of the spinning is 15-30°C, and the drafting pressure is 0.22-0.50MPa;

[0043] 2) forming a web of polyethylene terephthalate filaments obtained in step 1) and heat-treating the web to obtain a polyethylene terephthalate filament web;

[0044] The heat treatment temperature is 70-120°C and the treatment time is 50-100s;

[0045] 3) The polyethylene terephthalate filament web obtained in step 2) is needle-punched to obtain a polyethylene terephthalate filament felt.

[0046] The present invention uses low-melting-point modified polyethylene terephthalate with a melting point of 180-230°C as a sheath layer and unmodified polyethylene terephthalate with a melting point of 250-260°C as a core layer for spinning to obtain polyethylene terephthalate filaments with a sheath-core structure; the mass ratio of the sheath layer to the core layer is 1-4:6-9; the crosswind temperature of the spinning is 15-30°C, and the drafting pressure is 0.22-0.50MPa. In the present invention, the brand of the low-melting-point modified polyethylene terephthalate with a melting point of 180-230°C is preferably TRN-3320AC of Teijin Co., Ltd. of Japan. In the present invention, the brand of the unmodified polyethylene terephthalate with a melting point of 250-260°C is preferably any brand of commercially available polyester (fiber grade) composite spinning chips of Sinopec.

[0047] The present invention preferably spins the modified polyethylene terephthalate and polyethylene terephthalate after drying, and the drying temperature is preferably 160-180°C and the time is 4-8h. In the present invention, the mass ratio of the skin layer to the core layer is preferably 3:7. In the present invention, the side wind temperature of the spinning is preferably 24°C, and the drawing pressure is preferably 0.25MPa. In the present invention, the spinning step preferably includes: melting the skin layer and the core layer to obtain melts and then mixing them to form a skin-core structure composite melt; cooling the obtained skin-core structure composite melt under double side winds with a pressure of 4-10MPa and a side wind temperature of 15-30°C to obtain filaments; drawing the obtained filaments at a drawing temperature of 30-40°C and a drawing pressure of 0.22-0.50MPa. In the present invention, the fineness of the PET filament is preferably 3-6dtex, and the concentric circle diameter is preferably 6-22μm.

[0048] The present invention forms a web and heat-treats the obtained polyethylene terephthalate filaments to obtain a polyethylene terephthalate long fiber web; the temperature of the heat treatment is 70 to 120°C and the treatment time is 50 to 100 seconds. In the present invention, the web-forming conditions preferably include: forming the polyethylene terephthalate filaments into a long fiber web with a surface density of 60 to 1600 gsm under the action of tubular or slit suction wind.

[0049] In the present invention, the obtained polyethylene terephthalate filament web is needle-punched to obtain a polyethylene terephthalate filament felt. In the present invention, the needle-punching conditions preferably include: a needle-punching density of 50 to 150 times / m 2 , depth is 5 to 10 mm.

[0050] The present invention also provides a polyethylene terephthalate filament felt prepared by the preparation method described in the above technical solution, wherein the polyethylene terephthalate filament felt has a surface density of 900 to 1600 gsm and a thickness of 10 to 20 mm.

[0051] The present invention also provides the use of the polyethylene terephthalate filament felt described in the above technical solution in the preparation of automotive interior and exterior composite materials. In the present invention, the application preferably includes: subjecting the polyethylene terephthalate filament felt to steam molding to obtain an automotive interior and exterior composite material. In the present invention, the steam molding conditions preferably include: a steam temperature of 140 to 230°C, a ventilation time of 20 to 80s, a mold temperature of 140 to 230°C, a mold closing time of 40 to 100s, and a mold pressure of 200 to 500t. In the present invention, the thickness of the automotive interior and exterior composite material is preferably 1.5 to 3.0mm, and the gram weight is preferably 900 to 1600gsm. In the present invention, the polyethylene terephthalate filament felt can also be further molded to make interior and exterior materials such as automotive underbody guards, fenders, and trunk side trims.

[0052] In order to further illustrate the present invention, the present invention is described in detail below in conjunction with embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] A process for preparing a fully recyclable polyethylene terephthalate (PET) filament felt, wherein the PET filament felt is prepared by melt spinning low-melting-point PET and high-melting-point PET to form a core-skin structure ( Figure 1 ) The continuous filament is obtained by needle punching process, the low melting point PET is modified PET with a melting point of 210.4℃, and the high melting point PET is unmodified PET with a melting point of 255.7℃. The brand of the low melting point modified polyethylene terephthalate with a melting point of 210.4℃ is TRN-3320AC of Teijin Co., Ltd. of Japan. The brand of the unmodified polyethylene terephthalate with a melting point of 255.7℃ is any brand of the commercially available polyester (fiber grade) composite spinning special chips of Sinopec. The preparation process is composed of the following process route ( Figure 2 )composition:

[0055] S1: Drying. The low melting point PET particles and the high melting point PET particles are placed in an oven at 170°C for 8 hours for drying. The moisture content is less than 50ppm as the drying completion control index. If the moisture content requirement is not met, the drying time is further extended;

[0056] S2: Melting. The two particles are placed in two storage tanks at a skin-core weight ratio of 4:6. The skin PET screw is heated at 260°C and the core PET screw is heated at 285°C. The skin low melting point PET melt flows into the spinneret through the gap between the composite plate and the spinneret and intersects with the core PET melt at the spinneret entrance, and flows into the spinneret in a skin-core structure.

[0057] S3: Spinning. The melt flowing out of the spinneret is cooled and formed under the double-sided blowing action of the side wind blower at a temperature of 24°C. The filaments are introduced into the tubular drawing device through the air flow. The drawing air temperature is 24°C and the pressure is 0.25MPa, forming continuous PET filaments with a skin-core structure. The fineness distribution of the PET filaments is 3 to 6 dtex, and the concentric circle diameter is between 6 and 22μm.

[0058] S4: Web formation and heat treatment. The drawn PET filaments are introduced onto the net curtain under the action of a tubular or slit suction fan to form a PET long fiber web with a surface density of 400 gsm, and then transferred to an oven at a temperature of 70°C for heat treatment for 60 seconds.

[0059] S5: Needle punching and winding. The PET long fiber web is introduced into the needle punching machine, and the needle punching density is 100 times / m 2 , depth is 8mm, and after leaving the machine, it is rolled up and trimmed to form PET filament felt.

[0060] Example 2

[0061] The difference from Example 1 is that, S2: two kinds of particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7; the rest is the same as Example 1.

[0062] Example 3

[0063] The difference from Example 1 is that, S2: two kinds of particles are placed in two storage tanks at a skin-to-core weight ratio of 1:9; the rest is the same as Example 1.

[0064] Example 4

[0065] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0066] S3: side wind fan temperature 15℃;

[0067] The rest is the same as in Example 1.

[0068] Example 5

[0069] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0070] S3: side wind fan temperature 30℃;

[0071] The rest is the same as in Example 1.

[0072] Example 6

[0073] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0074] S3: The silk strips are introduced into the tubular drawing device through air flow, and the pressure is 0.22MPa;

[0075] The rest is the same as in Example 1.

[0076] Example 7

[0077] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0078] S3: The silk strips are introduced into the tubular drawing device through air flow, and the pressure is 0.50 MPa;

[0079] The rest is the same as in Example 1.

[0080] Example 8

[0081] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0082] S4: Transfer to an oven at 120°C for heat treatment;

[0083] The rest is the same as in Example 1.

[0084] Comparative Example 1

[0085] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0086] S3: The silk strips are introduced into the tubular drawing device through air flow, and the pressure is 0.20MPa;

[0087] The rest is the same as in Example 1.

[0088] Comparative Example 2

[0089] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0090] S3: side wind fan temperature 35℃;

[0091] The rest is the same as in Example 1.

[0092] Comparative Example 3

[0093] The difference from Example 1 is that, S2: the two particles are placed in two storage tanks at a skin-to-core weight ratio of 3:7;

[0094] S4: no heat treatment;

[0095] The rest is the same as in Example 1.

[0096] Examples 1-8 and Comparative Examples 1-3 respectively adjusted different skin-core weight ratios, side wind fan temperature, filament drawing pressure, and heat treatment oven temperature to prepare PET filament felts, and the specific parameters are shown in Table 1. The PET filament felt is evaluated by its single filament strength, and the test method refers to the "Test Method for Tensile Properties of Chemical Fiber Filaments" (GB / T 14337-2022).

[0097] Table 1 Optimization of preparation process parameters for a fully recyclable PET filament felt

[0098]

[0099] Examples 1-3 illustrate that as the cortex ratio decreases, the monofilament strength of the filament increases. However, attention should also be paid to problems such as poor bonding caused by too low a cortex ratio. Examples 2, 4, and 5 illustrate that the higher the temperature of the side wind fan, the greater the monofilament strength of the filament. This may be due to the high side wind temperature causing the filament to cool slowly, thereby increasing the crystallinity and mechanical strength of the PET filament. Examples 2, 6, and 7 illustrate that the greater the drawing pressure, the greater the monofilament strength of the filament. Examples 2 and 8 illustrate that the higher the heat treatment temperature, the greater the monofilament strength of the filament. Comparative Examples 1-3 show that the monofilament strength is lower when the drawing pressure is lower and no heat treatment is performed. Although the monofilament strength is higher when the side wind fan temperature is higher, the phenomenon of broken wires is prone to occur due to insufficient cooling temperature.

[0100] Example 9

[0101] A method for preparing an automotive interior and exterior composite material, comprising the following steps: the PET filament felt prepared in Example 8 is formed into an automotive interior and exterior composite material with a thickness of 1.5 mm and a gram weight of 900 gsm by steam molding, the steam temperature is 150°C, the ventilation time is 40 s, the mold temperature is 160°C, the mold closing time is 60 s, and the mold pressure is 300t.

[0102] Example 10

[0103] The difference from Example 9 is that the composite material for automobile interior and exterior decoration is 2.0 mm thick and 1200 gsm in weight; the rest is the same as Example 9.

[0104] Embodiment 11

[0105] The difference from Example 9 is that the composite material for automobile interior and exterior decoration is 2.6 mm thick and 1600 gsm in weight; the rest is the same as Example 9.

[0106] The vehicle bottom protection materials prepared in Examples 9-11 are shown in Figure 3 , basic properties are shown in Table 2. Among them, the tensile strength test refers to the "Determination of tensile properties of plastics Part 4 Test conditions for isotropic and orthogonal anisotropic fiber reinforced plastic composites" (ISO 527-42023) test; the long-term heat aging resistance test method is to place the composite material in an environment of 120°C for 312.5 hours, and there is no obvious change in appearance, no visible deformation, bending, sagging, whitening, stickiness, cracks, blistering, peeling and other defects that affect the appearance quality, and the tensile strength and other properties of the sample cannot decrease by more than 50% compared with the initial state; the average sound absorption coefficient is tested by an impedance tube, the test frequency range is 400-8000Hz, and the average sound absorption coefficient is the average of the sound absorption coefficients corresponding to the four main frequencies of 500, 1000, 2000, and 4000Hz that affect human hearing.

[0107] Table 2 Properties of a fully structural recyclable PET filament felt made into automotive composite materials

[0108] Example Thickness / mm Weight / gsm Tensile strength / MPa Heat deformation temperature / ℃ Average sound absorption coefficient* 9 1.5 900 13 / 25 120 0.56 10 2.0 1200 16 / 28 120 0.58 11 2.6 1600 25 / 54 120 0.60

[0109] Examples 9 to 11 show that the prepared composite materials for vehicles have good tensile strength, long-term heat aging resistance and sound absorption and noise reduction performance.

[0110] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a fully recyclable polyethylene terephthalate filament felt, characterized in that: The following steps are involved: 1) Spinning a polyethylene terephthalate filament having a sheath-core structure by using a low-melting-point modified polyethylene terephthalate having a melting point of 180 to 230° C. as a sheath layer and an unmodified polyethylene terephthalate having a melting point of 250 to 260° C. as a core layer; The mass ratio of the skin layer to the core layer is 1-4:6-9; The side wind temperature of the spinning is 15-30°C, and the drafting pressure is 0.22-0.50MPa; 2) forming a web of polyethylene terephthalate filaments obtained in step 1) and heat-treating the web to obtain a polyethylene terephthalate filament web; The heat treatment temperature is 70-120°C and the treatment time is 50-100s; 3) The polyethylene terephthalate filament web obtained in step 2) is needle-punched to obtain a polyethylene terephthalate filament felt.

2. The preparation method according to claim 1, characterized in that: The spinning step in step 1) comprises: melting the skin layer and the core layer separately to obtain melts and then mixing them to form a skin-core structure composite melt; The obtained composite melt of the skin-core structure is cooled and formed under a double side wind with a pressure of 4 to 10 MPa and a side wind temperature of 15 to 30° C. to obtain a filament; The obtained filaments are drawn at a drawing temperature of 30 to 40° C. and a drawing pressure of 0.22 to 0.50 MPa.

3. The preparation method according to claim 1, characterized in that: In the step 1), the polyethylene terephthalate filaments have a fineness of 3 to 6 dtex and a concentric circle diameter of 6 to 22 μm.

4. The preparation method according to claim 1, characterized in that: The conditions for forming the web in step 2) include: introducing the polyethylene terephthalate filaments onto a mesh curtain under the action of a tubular or slit suction fan to form a long fiber web with a surface density of 60 to 1600 gsm.

5. The preparation method according to claim 1, characterized in that: The conditions for the needle punching of the long fiber web in step 3) include: a needle punching density of 50 to 150 times / m 2 , depth is 5 to 10 mm.

6. A polyethylene terephthalate filament felt prepared by the preparation method according to any one of claims 1 to 5, wherein the polyethylene terephthalate filament felt has a surface density of 900 to 1600 gsm and a thickness of 10 to 20 mm.

7. Use of the polyethylene terephthalate filament felt according to claim 6 in preparing composite materials for automobile interior and exterior decoration.

8. The use according to claim 7, characterized in that: The application includes: subjecting the polyethylene terephthalate filament felt to steam molding to obtain a composite material for automobile interior and exterior decoration; The steam molding conditions include: steam temperature of 140-230° C., ventilation time of 20-80 seconds, mold temperature of 140-230° C., mold closing time of 40-100 seconds, and mold pressure of 200-500 tons.

9. The use according to claim 7, characterized in that The automobile interior and exterior decoration composite material has a thickness of 1.5 to 3.0 mm and a gram weight of 900 to 1600 gsm.

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