A flame-retardant automotive interior filler and a method of making the same

Abstract

The application provides a kind of flame-retardant automotive interior filler and its preparation method, and the flame-retardant automotive interior filler includes surface layer, bottom layer and intermediate structure layer between the surface layer and the bottom layer; the surface layer is glueless cotton, the intermediate structure layer is upright cotton, and the bottom layer is grid base cloth; the raw material of glueless cotton includes flame-retardant polyester staple fiber and low melting point fiber; the raw material of upright cotton includes flame-retardant polyester fiber and low melting point fiber; the raw material of grid base cloth includes flame-retardant polyester filament; the flame-retardant polyester staple fiber, flame-retardant polyester fiber and flame-retardant polyester filament all include the following raw materials by weight: polyester chip 100 parts, MBS resin 10-15 parts, nano diatomite / hexaphenoxycyclophosphazene composite flame retardant 8-12 parts, nano alumina / titanium dioxide composite material 0.7-1.2 parts, antioxidant 0.3-0.6 parts. The flame-retardant automotive interior filler of the application has good air permeability and durability, and also has excellent flame-retardant performance.

Description

Technical Field

[0001] This invention relates to the field of automotive interior filler technology, specifically to a flame-retardant automotive interior filler and its preparation method. Background Technology

[0002] Automotive interior fillers are an important part of building the interior environment of a car. They play a key role in aesthetics, practicality, and durability. These fillers are commonly used in the manufacture of components such as door panels, headliners, seat cushions, and floor mats.

[0003] Seat padding is a crucial component of automotive interiors. It typically consists of multiple layers of materials, including a base layer (such as springs, wire mesh, or rigid foam), a middle layer (such as soft foam), and a top layer (such as fabric, leather, or synthetic leather). These materials work together to provide the seat's comfort, support, and durability. However, the extensive use of foam in current seat padding results in relatively poor breathability. Prolonged use may lead to stuffiness and discomfort for passengers, and the material's relatively low strength makes it susceptible to wear and tear, even cracking, after extended use, thus affecting the seat's durability. Therefore, developing a breathable and durable automotive interior padding material is essential.

[0004] Furthermore, as automobiles are an essential tool for modern travel, people are increasingly emphasizing safety while pursuing comfort and aesthetics. Therefore, the requirements for the flame-retardant properties of automotive interior materials are also rising. If automotive interior fillers possess excellent flame-retardant properties, they can slow the spread of fire in the event of a fire, providing passengers with more time to escape. Moreover, flame-retardant fillers are self-extinguishing when burning, preventing large-scale combustion and thus reducing the harm to passengers from a fire. Summary of the Invention

[0005] The purpose of this invention is to provide a flame-retardant automotive interior filler and its preparation method. The flame-retardant automotive interior filler has good air permeability and durability, and at the same time has excellent flame-retardant properties.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A flame-retardant automotive interior filler includes a top layer, a bottom layer, and an intermediate structural layer located between the top layer and the bottom layer; the top layer is non-adhesive cotton, the intermediate structural layer is vertical cotton, and the bottom layer is a mesh backing fabric.

[0008] The flame-retardant automotive interior filler of this invention is a fiber composite with a sandwich structure consisting of a surface layer, a middle structural layer, and a bottom layer. The surface layer is non-adhesive cotton, the middle structural layer is 3D vertical cotton, and the bottom layer is a mesh backing fabric. The non-adhesive cotton, vertical cotton, and mesh backing fabric all have excellent breathability, so the automotive interior filler prepared in combination also has excellent breathability.

[0009] Furthermore, the upright cotton, serving as the main structural layer, possesses excellent resilience and is not easily deformed. Simultaneously, the dense and orderly fiber structure within this upright cotton allows it to maintain a stable shape and performance over a long period. This orderly structure helps prevent the spread of flames, and during combustion, the fiber structure rapidly forms a protective layer, isolating air and heat, thereby slowing the spread of fire. The non-adhesive cotton, serving as the surface layer, is soft, comfortable, and high-strength. When used as automotive interior filling in the manufacture of car seats and other components, it ensures excellent comfort and durability, making it resistant to damage. The bottom mesh fabric effectively enhances the overall structural strength of the flame-retardant automotive interior filling, enabling it to withstand significant pressure or tension without tearing or damage.

[0010] Preferably, the raw materials of the non-adhesive cotton include the following raw materials by weight percentage: 50-70% flame-retardant polyester staple fiber and 30-50% low-melting-point fiber;

[0011] The raw materials of the vertical cotton include the following raw materials by weight percentage: 75-85% flame-retardant polyester fiber and 15-25% low-melting-point fiber.

[0012] The raw material for the mesh base fabric includes flame-retardant polyester filaments.

[0013] Preferably, the flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament each comprise the following raw materials in parts by weight: 100 parts polyester chips, 10-15 parts MBS resin, 8-12 parts nano diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, 0.7-1.2 parts nano alumina / titanium dioxide composite material, and 0.3-0.6 parts antioxidant.

[0014] In the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant of this invention, the nano-diatomite forms a porous insulating layer at high temperature, which can block the diffusion path of flames and heat radiation. It can also absorb heat and slow down the spread of fire. On this basis, the added hexaphenoxycyclotriphosphazene can promote the char formation of polymers during combustion, and the phosphazene and benzene ring groups will further decompose to produce small molecule fragments, which further promotes the formation and stability of the char layer.

[0015] This invention uses a nano-alumina / titanium dioxide composite material as a reinforcing material, in which nano-titanium dioxide is dispersed in polyester. The reinforcing phase formed by this material improves the strength, toughness, and thermal stability of the polyester. Furthermore, this invention modifies the nano-titanium dioxide using alumina sol, loading nano-alumina onto the surface of the nano-titanium dioxide. This results in better dispersion of the nano-titanium dioxide and a significantly enhanced bond between the nano-titanium dioxide and the polyester, leading to superior mechanical properties of the flame-retardant polyester fibers. Moreover, because nano-alumina is dispersed on the surface of the nano-titanium dioxide, the nano-alumina also possesses certain flame-retardant properties, further improving the flame-retardant performance of the polyester fibers. Simultaneously, the nano-alumina / titanium dioxide composite material of this invention exhibits good antibacterial effects, thus enabling the polyester fibers to demonstrate excellent antibacterial properties.

[0016] Preferably, the preparation method of the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant includes the following steps:

[0017] Nano-diatomaceous earth with a particle size of 200-300 nm is dispersed in acetone at 20-25 times its mass. Then, 10-15% of hexaphenoxycyclotriphosphazene by mass of nano-diatomaceous earth and 1-1.5% of γ-glycidoxypropyltrimethoxysilane by mass of nano-diatomaceous earth are added. The mixture is heated to 40-45°C and stirred at a constant temperature for 2-3 hours. Then, the mixture is concentrated under reduced pressure to remove acetone. The material after acetone removal is ground and dispersed to obtain the nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant.

[0018] In preparing the composite flame retardant, this invention involves adding nano-diatomaceous earth, hexaphenoxycyclotriphosphazene, and an appropriate amount of γ-glycidyl etheroxypropyltrimethoxysilane to acetone. This allows the hexaphenoxycyclotriphosphazene to be adsorbed onto the nano-diatomaceous earth, resulting in a high degree of uniformity in the mixing of the nano-diatomaceous earth and the hexaphenoxycyclotriphosphazene. Furthermore, the nano-diatomaceous earth surface has numerous active groups, enhancing its bonding strength with the polyester. Consequently, the composite flame retardant significantly improves the flame retardant properties of the polyester without adversely affecting its mechanical properties.

[0019] Preferably, the preparation method of the nano-alumina / titanium dioxide composite material includes the following steps: adding deionized water to a reactor, then adding nano-titanium dioxide and alumina sol, and performing ultrasonic treatment while stirring for 1-2 hours. Then, sealing the reactor, evacuating to -0.09 to -0.08 MPa, maintaining for 2-3 hours, drying in an electric heating drying oven at 85-90°C, and then heating the obtained powder to 800-850°C under a nitrogen atmosphere and holding for 2-2.5 hours to obtain the nano-alumina / titanium dioxide composite material after dispersion.

[0020] Preferably, the mass ratio of deionized water, nano-titanium dioxide, and alumina sol is 200:5~10:2~4; the particle size of the nano-titanium dioxide is 150~200nm; and the solid content of the alumina sol is 20~25%, wherein the average particle size of alumina is 30~50nm.

[0021] Preferably, the preparation methods of the flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament all include the following steps:

[0022] 1 / 3 to 1 / 2 of the polyester chips are mixed with MBS resin, nano diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, nano alumina / titanium dioxide composite material, and antioxidant, and then dried to obtain a dried mixture. The dried mixture is then placed in a twin-screw extruder for blending melt extrusion granulation to obtain flame-retardant polyester granules.

[0023] The remaining polyester chips are dried, mixed with the flame-retardant polyester granules, and then melt-spun to obtain blended flame-retardant polyester fibers of the target fineness.

[0024] The flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament are obtained by cutting and processing a blend of flame-retardant polyester fibers of corresponding fineness.

[0025] Preferably, the preparation method of the non-adhesive cotton includes the following steps: mixing flame-retardant polyester short fibers and low-melting-point fibers and placing them in an opening machine for opening treatment, then placing them in a carding machine for carding into a fiber web, then laying the web through a web laying machine, and then sending them to a setting machine for hot pressing and setting to obtain non-adhesive cotton;

[0026] The preparation method of the vertical cotton includes the following steps: after mixing flame-retardant polyester fiber and low melting point fiber, the mixture is placed in an opening machine for opening treatment, then placed in a carding machine for carding into a fiber web, and then the fiber web is placed in a vertical web laying machine for vertical web laying, three-dimensional molding, and then heated to obtain vertical cotton.

[0027] The preparation method of the mesh base fabric includes the following steps: warping, weaving and finishing flame-retardant polyester filaments to prepare the mesh base fabric.

[0028] Preferably, the surface layer and the intermediate structural layer, as well as the intermediate structural layer and the bottom layer, are bonded together by hot melt adhesive or by flame bonding.

[0029] As a general inventive concept, this invention provides a method for preparing a flame-retardant automotive interior filler, the method comprising the following steps: first, bonding the upper surface of the bottom layer with an intermediate structural layer using hot melt adhesive to form a double-layer structure; then bonding the side of the double-layer structure away from the bottom layer with a surface layer using hot melt adhesive to obtain the flame-retardant automotive interior filler;

[0030] Alternatively, the preparation method may include the following steps: flame bonding the upper surface of the bottom layer with the intermediate structural layer using a flame bonding machine, and after cooling, forming a double-layer structure; then flame bonding the side of the double-layer structure away from the bottom layer with the surface layer using a flame bonding machine, and after cooling, the flame-retardant automotive interior filler is obtained.

[0031] The beneficial effects of this invention are:

[0032] 1. The flame-retardant automotive interior filling material of this invention is prepared by combining non-adhesive cotton, upright cotton, and mesh base fabric, which makes the overall structure of the resulting interior filling material stable, breathable and durable, and has good flame retardancy. This interior filling material can also be widely used as a filling material in automotive interiors, seats, headrests, etc.

[0033] 2. In order to further improve the flame retardancy and strength of flame retardant automotive interior filling materials, this invention has developed a new type of blended flame retardant polyester fiber, which can be used as a raw material for preparing non-adhesive cotton, vertical cotton, and mesh base fabric.

[0034] The flame-retardant polyester fiber uses a nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant. This composite flame retardant is prepared by combining nano-diatomaceous earth and hexaphenoxycyclotriphosphazene using a specific method. The synergistic effect of each flame retardant significantly improves the flame-retardant performance of the polyester fiber without adversely affecting its mechanical properties. Furthermore, using a nano-alumina / titanium dioxide composite material as a reinforcing agent, compared to using nano-titanium dioxide, further enhances the mechanical properties of the flame-retardant polyester fiber, thereby improving the durability of the flame-retardant automotive interior filling material. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the structure of the flame-retardant automotive interior filler of the present invention;

[0037] In the diagram: 1. Bottom layer; 2. Intermediate structural layer; 3. Top layer. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1:

[0040] A flame-retardant automotive interior filler, such as Figure 1 As shown, it includes a top layer 3, a bottom layer 1, and an intermediate structural layer 2 located between the top layer 3 and the bottom layer 1; the top layer 3 and the intermediate structural layer 2, as well as the intermediate structural layer 2 and the bottom layer 1, are bonded together by hot melt adhesive.

[0041] The top layer 3 is non-adhesive cotton, the middle structural layer 2 is vertical cotton, and the bottom layer 1 is a mesh backing fabric.

[0042] The raw materials for non-woven cotton include the following weight percentages: 60% flame-retardant polyester staple fiber and 40% 4080 low-melting-point fiber; the raw materials for upright cotton include the following weight percentages: 80% flame-retardant polyester fiber and 20% 4080 low-melting-point fiber. The raw material for the mesh backing fabric includes flame-retardant polyester filament.

[0043] In this embodiment, the flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament all contain the following raw materials in parts by weight: 100 parts polyester chips, 13 parts MBS resin, 10 parts nano diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, 1.1 parts nano alumina / titanium dioxide composite material, and 0.5 parts antioxidant 1010.

[0044] The preparation method of the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant in this embodiment includes the following steps:

[0045] Nano-diatomaceous earth with a particle size of 200~300nm was dispersed in acetone at 25 times its mass. Then, 14% of the nano-diatomaceous earth mass of hexaphenoxycyclotriphosphazene and 1.5% of the nano-diatomaceous earth mass of γ-glycidoxypropyltrimethoxysilane were added. The mixture was heated to 42℃ and stirred at a constant temperature for 3 hours. Then, the mixture was concentrated under reduced pressure to remove the acetone. The material after removing the acetone was ground and dispersed to obtain a nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant.

[0046] The preparation method of the nano-alumina / titanium dioxide composite material in this embodiment includes the following steps: adding deionized water to a reactor, then adding nano-titanium dioxide and alumina sol, and ultrasonically treating while stirring for 1.5 hours. Then, sealing the reactor, evacuating to -0.09 MPa, maintaining this temperature for 2.5 hours, and drying in an electric heating drying oven at 90°C. Then, heating the resulting powder to 820°C under a nitrogen atmosphere and maintaining this temperature for 2.5 hours, and dispersing it to obtain the nano-alumina / titanium dioxide composite material. The mass ratio of deionized water, nano-titanium dioxide, and alumina sol is 200:9:3; the particle size of nano-titanium dioxide is 150~200 nm; the solid content of alumina sol is 20%, and the average particle size of alumina is 30 nm.

[0047] The preparation methods of flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament in this embodiment all include the following steps:

[0048] One-third of the polyester chips were mixed with MBS resin, nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant, nano-alumina / titanium dioxide composite material, and antioxidant, and then dried to obtain a dried mixture. The dried mixture was placed in a twin-screw extruder for blending melt extrusion granulation to obtain flame-retardant polyester granules. The remaining polyester chips were dried, mixed with the flame-retardant polyester granules, and then melt-spun to obtain blended flame-retardant polyester fibers of the target fineness.

[0049] In this embodiment, flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament are obtained by cutting and processing a blend of flame-retardant polyester fibers of corresponding fineness.

[0050] In this embodiment, the preparation method of non-adhesive cotton includes the following steps: flame-retardant polyester staple fiber and 4080 low melting point fiber are mixed and placed in an opening machine for opening treatment, then placed in a carding machine for carding into a fiber web, then laid in a web laying machine, and then sent to a setting machine for hot pressing and setting to obtain non-adhesive cotton.

[0051] The preparation method of upright cotton includes the following steps: flame-retardant polyester fiber and 4080 low melting point fiber are mixed and placed in an opening machine for opening treatment, then placed in a carding machine for carding into a fiber web, and then the fiber web is placed in a vertical web laying machine for vertical web laying, three-dimensional molding, and then heated to obtain upright cotton.

[0052] The preparation method of the mesh base fabric includes the following steps: warping, weaving and finishing of flame-retardant polyester filaments to obtain the mesh base fabric.

[0053] The method for preparing the flame-retardant automotive interior filler in this embodiment includes the following steps: first, the upper surface of the bottom layer 1 is bonded to the intermediate structural layer 2 with hot melt adhesive to form a double-layer structure; then, the side of the double-layer structure away from the bottom layer 1 is bonded to the surface layer 3 with hot melt adhesive to prepare the flame-retardant automotive interior filler.

[0054] Example 2:

[0055] A flame-retardant automotive interior filler, unlike Example 1, has a flame-bonded connection between the top layer 3 and the intermediate structural layer 2, as well as between the intermediate structural layer 2 and the bottom layer 1.

[0056] The raw materials for non-woven cotton include the following weight percentages: 50% flame-retardant polyester staple fiber and 50% 4080 low-melting-point fiber; the raw materials for upright cotton include the following weight percentages: 78% flame-retardant polyester fiber and 22% 4080 low-melting-point fiber. The raw material for the mesh backing fabric includes flame-retardant polyester filament.

[0057] In this embodiment, the flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament all contain the following raw materials in parts by weight: 100 parts polyester chips, 12 parts MBS resin, 12 parts nano diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, 0.7 parts nano alumina / titanium dioxide composite material, and 0.3 parts antioxidant 1010.

[0058] The preparation method of the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant in this embodiment includes the following steps:

[0059] Nano-diatomaceous earth with a particle size of 200~300nm was dispersed in acetone at 25 times its mass. Then, 15% of hexaphenoxycyclotriphosphazene by mass of nano-diatomaceous earth and 1.5% of γ-glycidoxypropyltrimethoxysilane by mass of nano-diatomaceous earth were added. The mixture was heated to 45℃ and stirred at a constant temperature for 3 hours. Then, the mixture was concentrated under reduced pressure to remove the acetone. The material after removing the acetone was ground and dispersed to obtain a nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant.

[0060] The preparation method of the nano-alumina / titanium dioxide composite material in this embodiment includes the following steps: adding deionized water to a reactor, then adding nano-titanium dioxide and alumina sol, and ultrasonically treating the mixture while stirring for 2 hours. The reactor is then sealed, evacuated to -0.09 MPa, and maintained for 3 hours. The mixture is then dried in an electric heating drying oven at 85°C. The resulting powder is then heated to 850°C under a nitrogen atmosphere and held at that temperature for 2.5 hours. The nano-alumina / titanium dioxide composite material is then dispersed. The mass ratio of deionized water, nano-titanium dioxide, and alumina sol is 200:10:3. The particle size of the nano-titanium dioxide is 150~200 nm. The solid content of the alumina sol is 25%, and the average particle size of the alumina is 50 nm.

[0061] The method for preparing the flame-retardant automotive interior filler in this embodiment includes the following steps: flame bonding the upper surface of the bottom layer 1 with the intermediate structural layer 2 using a flame bonding machine, and after cooling, forming a double-layer structure; then flame bonding the side of the double-layer structure away from the bottom layer 1 with the surface layer 3 using a flame bonding machine, and after cooling, the flame-retardant automotive interior filler is obtained.

[0062] Example 3:

[0063] A flame-retardant automotive interior filler, differing from Example 1, comprises the following raw materials by weight percentage: 55% flame-retardant polyester staple fiber and 45% 4080 low-melting-point fiber; and the raw materials for the upright cotton comprise the following raw materials by weight percentage: 85% flame-retardant polyester fiber and 15% 4080 low-melting-point fiber. The mesh backing fabric comprises flame-retardant polyester filament.

[0064] In this embodiment, the flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament all contain the following raw materials in parts by weight: 100 parts polyester chips, 10 parts MBS resin, 10 parts nano diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, 1.2 parts nano alumina / titanium dioxide composite material, and 0.5 parts antioxidant 1010.

[0065] The preparation method of the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant in this embodiment includes the following steps:

[0066] Nano-diatomaceous earth with a particle size of 200~300nm was dispersed in acetone at 20 times its mass. Then, 12% by mass of hexaphenoxycyclotriphosphazene and 1% by mass of γ-glycidoxypropyltrimethoxysilane were added. The mixture was heated to 45℃ and stirred for 2 hours. Then, the mixture was concentrated under reduced pressure to remove the acetone. The material after removing the acetone was ground and dispersed to obtain the nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant.

[0067] The preparation method of the nano-alumina / titanium dioxide composite material in this embodiment includes the following steps: adding deionized water to a reactor, then adding nano-titanium dioxide and alumina sol, and ultrasonically treating while stirring for 1 hour. Then, sealing the reactor, evacuating to -0.08 MPa, maintaining for 2 hours, and drying in an electric heating drying oven at 90°C. Then, heating the obtained powder to 850°C under a nitrogen atmosphere and holding for 2 hours, and dispersing to obtain the nano-alumina / titanium dioxide composite material; wherein, the mass ratio of deionized water, nano-titanium dioxide, and alumina sol is 200:8:2; the particle size of nano-titanium dioxide is 150~200 nm; the solid content of the alumina sol is 25%, wherein the average particle size of alumina is 50 nm.

[0068] Example 4:

[0069] A flame-retardant automotive interior filler, unlike Example 1, has a flame-bonded connection between the top layer 3 and the intermediate structural layer 2, as well as between the intermediate structural layer 2 and the bottom layer 1.

[0070] The raw materials for non-woven cotton include the following weight percentages: 70% flame-retardant polyester staple fiber and 30% 4080 low-melting-point fiber; the raw materials for upright cotton include the following weight percentages: 75% flame-retardant polyester fiber and 25% 4080 low-melting-point fiber. The raw material for the mesh backing fabric includes flame-retardant polyester filament.

[0071] In this embodiment, the flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament all contain the following raw materials in parts by weight: 100 parts polyester chips, 15 parts MBS resin, 8 parts nano diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, 1 part nano alumina / titanium dioxide composite material, and 0.6 parts antioxidant.

[0072] The preparation method of the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant in this embodiment includes the following steps:

[0073] Nano-diatomaceous earth with a particle size of 200-300 nm was dispersed in acetone at 20 times its mass. Then, 10% of the nano-diatomaceous earth mass of hexaphenoxycyclotriphosphazene and 1.2% of the nano-diatomaceous earth mass of γ-glycidoxypropyltrimethoxysilane were added. The mixture was heated to 40°C and stirred at a constant temperature for 2.5 h. Then, the mixture was concentrated under reduced pressure to remove the acetone. The material after removing the acetone was ground and dispersed to obtain the nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant.

[0074] The preparation method of the nano-alumina / titanium dioxide composite material in this embodiment includes the following steps: adding deionized water to a reactor, then adding nano-titanium dioxide and alumina sol, and ultrasonically treating while stirring for 1.5 hours. Then, sealing the reactor, evacuating to -0.08 MPa, maintaining this temperature for 3 hours, and drying in an electric heating drying oven at 90°C. Then, heating the resulting powder to 800°C under a nitrogen atmosphere and holding it at this temperature for 2.5 hours, and dispersing it to obtain the nano-alumina / titanium dioxide composite material. The mass ratio of deionized water, nano-titanium dioxide, and alumina sol is 200:5:4. The particle size of the nano-titanium dioxide is 150~200 nm. The solid content of the alumina sol is 20%, and the average particle size of the alumina is 30 nm.

[0075] The method for preparing the flame-retardant automotive interior filler in this embodiment includes the following steps: flame bonding the upper surface of the bottom layer 1 with the intermediate structural layer 2 using a flame bonding machine, and after cooling, forming a double-layer structure; then flame bonding the side of the double-layer structure away from the bottom layer 1 with the surface layer 3 using a flame bonding machine, and after cooling, the flame-retardant automotive interior filler is obtained.

[0076] Comparative Example 1:

[0077] Unlike Example 4, the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant was replaced with a mixture of nano-diatomite and hexaphenoxycyclotriphosphazene in a mass ratio of 1:0.1.

[0078] Comparative Example 2:

[0079] Unlike Example 4, the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant was replaced with a mixture of nano-diatomite and hexaphenoxycyclotriphosphazene in a mass ratio of 1:1.

[0080] Comparative Example 3:

[0081] Unlike Example 4, the nano-alumina / titanium dioxide composite material was replaced with nano-titanium dioxide.

[0082] Performance testing:

[0083] 1. For the blended flame-retardant polyester fiber materials prepared in Examples 1-4 and Comparative Examples 1-3, the limiting oxygen index was tested according to the method in GB / T2406.2-2009, and the vertical flammability rating was tested according to the method in GB / T 2408-2008. The specific test results are shown in Table 1.

[0084] Table 1:

[0085] Limiting oxygen index / % Vertical Burning Rating Example 1 37.6 V-0 Example 2 39.4 V-0 Example 3 38.9 V-0 Example 4 38.0 V-0 Comparative Example 1 34.0 V-0 Comparative Example 2 38.6 V-0 Comparative Example 3 37.6 V-0

[0086] As shown in Table 1, the flame-retardant polyester fibers prepared in Examples 1-4 of this invention exhibit excellent flame-retardant properties. A comparison between Example 4 and Comparative Example 1 shows that if the method of this invention is not used to composite the nano-diatomaceous earth and hexaphenoxycyclotriphosphazene composite flame retardant, the flame-retardant properties will decrease. However, as shown in Comparative Examples 1 and 2, increasing the amount of hexaphenoxycyclotriphosphazene will improve the flame-retardant properties, but subsequent tests show that it will significantly reduce the mechanical properties.

[0087] 2. Flame-retardant blended polyester fibers with a fineness of 5 dtex were prepared according to the methods in Examples 1-4 and Comparative Examples 1-3. The breaking strength and elongation at break were tested according to GB / T 14337-2008, and the moisture regain was tested according to GB / T 3503-2008. Specific test results are shown in Table 2.

[0088] Table 2:

[0089] Fracture strength / (cN / dtex) Elongation at break / / % Moisture regain / % Example 1 6.02 42.2 0.25 Example 2 5.93 40.6 0.27 Example 3 6.06 41.7 0.24 Example 4 6.17 43.7 0.29 Comparative Example 1 5.32 35.8 0.32 Comparative Example 2 4.10 27.5 0.34 Comparative Example 3 5.42 37.1 0.29

[0090] Table 2 shows that the blended flame-retardant polyester fibers prepared using the methods in Examples 1-4 of this invention exhibit high breaking strength and elongation at break, high overall strength, and good toughness, making the flame-retardant automotive interior fillers less susceptible to damage from external forces. Simultaneously, they have a low moisture regain, which helps maintain the comfort of the flame-retardant automotive interior fillers. Examples 4 and Comparative Examples 1-2 show that different compositions of the flame retardant and different preparation methods can significantly reduce the mechanical properties of the flame-retardant polyester fibers. A comparison between Example 4 and Comparative Example 3 shows that without appropriate modification of the nano-titanium dioxide, the strength of the flame-retardant polyester fibers decreases.

[0091] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flame-retardant automotive interior filler, characterized in that, The flame-retardant automotive interior filler includes a top layer, a bottom layer, and an intermediate structural layer between the top layer and the bottom layer; the top layer is non-adhesive cotton, the intermediate structural layer is vertical cotton, and the bottom layer is a mesh backing fabric. The raw materials of the non-adhesive cotton include the following raw materials by weight percentage: 50-70% flame-retardant polyester staple fiber and 30-50% low-melting-point fiber; The raw materials of the vertical cotton include the following raw materials by weight percentage: 75-85% flame-retardant polyester fiber and 15-25% low-melting-point fiber; The raw material of the mesh base fabric includes flame-retardant polyester filament; The flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament all contain the following raw materials in parts by weight: 100 parts polyester chips, 10-15 parts MBS resin, 8-12 parts nano diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, 0.7-1.2 parts nano alumina / nano titanium dioxide composite material, and 0.3-0.6 parts antioxidant. The preparation method of the nano-diatomite / hexaphenoxycyclotriphosphazene composite flame retardant includes the following steps: Nano-diatomaceous earth with a particle size of 200-300 nm is dispersed in acetone at 20-25 times its mass. Then, 10-15% of hexaphenoxycyclotriphosphazene by mass of nano-diatomaceous earth and 1-1.5% of γ-glycidoxypropyltrimethoxysilane by mass of nano-diatomaceous earth are added. The mixture is heated to 40-45°C and stirred at a constant temperature for 2-3 hours. Then, the mixture is concentrated under reduced pressure to remove acetone. The material after acetone removal is ground and dispersed to obtain the nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant.

2. The flame-retardant automotive interior filler as described in claim 1, characterized in that, The preparation method of the nano-alumina / nano-titanium dioxide composite material includes the following steps: adding deionized water to a reactor, then adding nano-titanium dioxide and alumina sol, and ultrasonically treating while stirring for 1-2 hours. Then, sealing the reactor, evacuating to -0.09 to -0.08 MPa, maintaining for 2-3 hours, and drying in an electric heating drying oven at 85-90°C. Then, heating the obtained powder to 800-850°C under a nitrogen atmosphere and holding for 2-2.5 hours, and dispersing to obtain the nano-alumina / nano-titanium dioxide composite material.

3. The flame-retardant automotive interior filler as described in claim 2, characterized in that, The mass ratio of deionized water, nano-titanium dioxide, and alumina sol is 200:5~10:2~4; the particle size of the nano-titanium dioxide is 150~200nm; the solid content of the alumina sol is 20~25%, wherein the average particle size of alumina is 30~50nm.

4. The flame-retardant automotive interior filler as described in claim 1, characterized in that, The preparation methods of the flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament all include the following steps: One-third to one-half of the polyester chips were mixed with MBS resin, nano-diatomaceous earth / hexaphenoxycyclotriphosphazene composite flame retardant, nano-alumina / nano-titanium dioxide composite material, and antioxidant, and then dried to obtain a dried mixture. The dried mixture was placed in a twin-screw extruder for blending melt extrusion granulation to obtain flame-retardant polyester granules. The remaining polyester chips were dried, mixed with the flame-retardant polyester granules, and then melt-spun to obtain blended flame-retardant polyester fibers of the target fineness. The flame-retardant polyester staple fiber, flame-retardant polyester fiber, and flame-retardant polyester filament are obtained by cutting and processing a blend of flame-retardant polyester fibers of corresponding fineness.

5. The flame-retardant automotive interior filler as described in claim 1, characterized in that, The preparation method of the non-adhesive cotton includes the following steps: flame-retardant polyester short fibers and low-melting-point fibers are mixed and placed in an opening machine for opening treatment, then placed in a carding machine for carding into a fiber web, then laid in a web laying machine, and then sent to a setting machine for hot pressing and setting to obtain non-adhesive cotton. The preparation method of the vertical cotton includes the following steps: after mixing flame-retardant polyester fiber and low melting point fiber, the mixture is placed in an opening machine for opening treatment, then placed in a carding machine for carding into a fiber web, and then the fiber web is placed in a vertical web laying machine for vertical web laying, three-dimensional molding, and then heated to obtain vertical cotton. The preparation method of the mesh base fabric includes the following steps: warping, weaving and finishing flame-retardant polyester filaments to prepare the mesh base fabric.

6. The flame-retardant automotive interior filler as described in claim 1, characterized in that, The surface layer and the intermediate structural layer, as well as the intermediate structural layer and the bottom layer, are bonded together by hot melt adhesive or by flame bonding.

7. A method for preparing a flame-retardant automotive interior filler as described in any one of claims 1 to 6, characterized in that, The preparation method includes the following steps: first, the upper surface of the bottom layer is bonded to the intermediate structural layer with hot melt adhesive to form a double-layer structure; then, the side of the double-layer structure away from the bottom layer is bonded to the surface layer with hot melt adhesive to prepare the flame-retardant automotive interior filler. Alternatively, the preparation method may include the following steps: flame bonding the upper surface of the bottom layer with the intermediate structural layer using a flame bonding machine, and after cooling, forming a double-layer structure; then flame bonding the side of the double-layer structure away from the bottom layer with the surface layer using a flame bonding machine, and after cooling, the flame-retardant automotive interior filler is obtained.

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