An environmentally friendly, high-strength automotive roof and its preparation method

Abstract

This invention relates to the field of automotive interior technology, specifically disclosing an environmentally friendly, high-strength automotive headliner. From bottom to top, it comprises: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt. Both the first and second toughening fiber felts are made of toughening fibers. The first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer. The multi-layered structure of this automotive headliner features tight adhesion, preventing interlayer separation, good external rigidity, and no deformation. It also exhibits excellent sound absorption performance, is odorless, and is safe and environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of automotive interior technology, and in particular to an environmentally friendly, high-strength automotive headliner and its preparation method. Background Technology

[0002] China has become a major automobile producer and seller, with annual production and sales exceeding 20 million vehicles. While existing automotive roofs can basically meet the needs of the automotive industry, they also suffer from the drawback of being unable to recycle materials after disposal, which has a significant impact on the environment.

[0003] The car roof is a crucial component of the vehicle's interior, serving not only as a decorative element but also providing effective heat and sound insulation. Current car roofs, made of metal with a painted exterior and soft-touch interior trim, tend to absorb heat in summer, causing the interior temperature to rise rapidly. This heat is difficult to dissipate, increasing the cost of air conditioning during travel and negatively impacting environmental protection.

[0004] Meanwhile, with social development and technological progress, people are placing newer and higher demands on car roofs. Polyurethane substrates have properties such as heat insulation, sound absorption, shock absorption, flame retardancy, and aesthetics, and are currently widely used. However, when the temperature is high, the panels are prone to releasing harmful volatile substances after being heated, affecting the air quality and interior environment of the passenger compartment. Moreover, the products are relatively brittle, which limits their use.

[0005] Existing automotive roofs use composite fiber materials to improve the brittleness of polyurethane. Although the above composite materials can basically meet the needs of the automotive industry, there are small particles generated during the processing that can cause certain hazards to production personnel. Long-term exposure can lead to diseases such as pneumoconiosis, which are irreversible.

[0006] The current research direction for cutting-edge automotive roof technology is to develop a car roof that is not only environmentally friendly, but also has excellent rigidity, flexural strength, and compressive strength. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by proposing an environmentally friendly, high-strength automotive roof and its preparation method.

[0008] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt.

[0009] The first and second toughening fiber felts are both made of toughening fiber felt; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0010] Preferably, the polyurethane substrate is prepared by the following specific operation: polyether polyol is continuously stirred, and triethanolamine, catalyst, pore-opening agent, foaming agent, water, silicone oil and activated carbon fiber are added in sequence during the stirring process. After the addition is complete, the mixture is stirred at 5-15°C for 10-20 minutes, and then toluene diisocyanate is added. The temperature is adjusted to 5-10°C and stirred evenly. The mixture is then cured and cooled.

[0011] Preferably, the polyether polyol has a molecular weight of 2500-3500 and a hydroxyl value of 25-30 mg KOH / g.

[0012] Preferably, the catalyst is dibutyltin dilaurate.

[0013] Preferably, the foaming agent is HFC-245fa (the main active ingredient is pentafluoropropane).

[0014] Preferably, the pore-opening agent is at least one of Evonik O-501, Evonik O-500, and Mistex AK9905.

[0015] Preferably, the mass ratio of polyether polyol, triethanolamine, catalyst, cell opener, foaming agent, water, silicone oil, activated carbon fiber, and toluene diisocyanate is 30-60:0.1-1:0.01-0.1:1-2:1-2:5-10:1-2:5-15:30-50.

[0016] Preferably, the diameter of the toughening fiber is 3-10 μm.

[0017] Preferably, the toughening fiber is prepared by the following specific operation: ultra-high molecular weight polyethylene is added to decahydronaphthalene, stirred at 90-95℃ for 1-2 hours, silicate cement and chitosan are added and stirred evenly, extruded from the spinneret holes, cooled, cured, and dried to remove solvent.

[0018] Preferably, the ultra-high molecular weight polyethylene has a molecular weight of 3-4 million, and the silicate cement has a particle size of 5-15 μm.

[0019] Preferably, the mass ratio of ultra-high molecular weight polyethylene, silicate cement, and chitosan is 10-20:1-5:1-2.

[0020] Preferably, the composite ethylene-vinyl acetate copolymer is prepared by the following specific operation: the ethylene-vinyl acetate copolymer, carboxyl-terminated polyamide amine, nano titanium dioxide, activated carbon, pentaerythritol tetraacrylate, tert-butyl peroxide-2-ethylhexyl ester, and antioxidant are mixed evenly and extruded at 180-220°C.

[0021] Preferably, the mass ratio of ethylene-vinyl acetate copolymer, carboxyl-terminated polyamide amine, nano titanium dioxide, activated carbon, pentaerythritol tetraacrylate, tert-butylperoxide-2-ethylhexyl ester, and antioxidant is 40-60:1-3:1-2:5-15:1-2:1-2:1-2.

[0022] The above-mentioned method for preparing an environmentally friendly high-strength automotive roof includes the following steps: stacking the materials in sequence, hot-pressing at 130-150℃, with a molding pressure of 8-10MPa, a molding time of 10-20s, and cooling and setting for 10-20s.

[0023] Beneficial effects:

[0024] 1. This invention uses ultra-high molecular weight polyethylene, silicate cement, and chitosan to form a composite spinning process, which results in a toughened fiber felt that has better adhesion and bonding with the composite ethylene-vinyl acetate copolymer compared to glass fiber. After high-temperature pressing, it not only has good rigidity but also does not crack during use. At the same time, it has high tear resistance, which greatly improves economic benefits and has good practicality, application prospects, and value.

[0025] 2. This invention does not use glass fiber, which not only has high tear resistance, but also effectively avoids the harm to production personnel caused by fine particles generated during processing. While improving quality, it greatly improves the structural strength and performance of the car roof. The combination of toughened fiber felt and polyurethane substrate can simultaneously achieve lightweight and environmental protection of the product, solve the weaknesses of existing car roof materials, and is an ideal new material to replace car roofs.

[0026] 3. This invention adds nano-titanium dioxide and activated carbon to the composite ethylene-vinyl acetate copolymer, which enables the roof to adsorb and degrade aldehydes. During the use of the car roof, it can reduce the VOC value in the car, resulting in good environmental protection and keeping the air inside the car fresh.

[0027] 4. The multi-layer structure of the car roof of this invention has tight adhesion to prevent separation between layers. The roof has good external rigidity and is non-deformable. In addition, it has excellent sound absorption performance, no odor, and is safe and environmentally friendly, making it suitable for large-scale promotion and use. Attached Figure Description

[0028] Figure 1 This is a comparison chart of the tensile strength and elongation at break of the car roofs obtained in Example 5 and Comparative Examples 1-2.

[0029] Figure 2 The image shows a comparison of the tear strength and compression set of the car roofs obtained in Example 5 and Comparative Examples 1-2. Detailed Implementation

[0030] The present invention will be further explained below with reference to specific embodiments.

[0031] Example 1

[0032] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt.

[0033] The first and second toughening fiber felts are both made of toughening fibers with a diameter of 3-10 μm; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0034] The polyurethane substrate has a thickness of 10 mm, the toughening fiber felt has a thickness of 0.1 mm, and the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer all have a thickness of 0.1 mm.

[0035] The polyurethane substrate was prepared by the following specific operation: 30 kg of polyether polyol with a molecular weight of 3000 and a hydroxyl value of 28 mg KOH / g was continuously stirred. During the stirring process, 0.1 kg of triethanolamine, 0.01 kg of dibutyltin dilaurate, 1 kg of Evonik O-501, 1 kg of foaming agent HFC-245fa, 5 kg of water, 1 kg of silicone oil, and 5 kg of activated carbon fiber were added in sequence. After the addition was complete, the mixture was stirred at 5°C for 10 min. Then, 30 kg of toluene diisocyanate was added and stirred evenly at 5°C. The mixture was then poured into a mold for curing, demolded, and cooled.

[0036] The toughening fiber is prepared by the following specific operation: 10 kg of ultra-high molecular weight polyethylene with a molecular weight of 3 million is added to 40 kg of decahydronaphthalene and stirred at 90℃ for 1 h. Then, 1 kg of silicate cement with a particle size of 5-15 μm and 1 kg of chitosan are added and stirred evenly. The mixture is then extruded from the spinneret orifice, cooled, cured, and dried to remove the solvent.

[0037] The composite ethylene-vinyl acetate copolymer is prepared by the following specific operation: 40 kg of ethylene-vinyl acetate copolymer, 1 kg of carboxyl-terminated polyamide amine, 1 kg of nano titanium dioxide, 5 kg of activated carbon, 1 kg of pentaerythritol tetraacrylate, 1 kg of tert-butyl peroxide-2-ethylhexyl ester, and 1 kg of antioxidant are mixed evenly and fed into an extruder and extruded at a temperature of 180℃.

[0038] The above-mentioned method for preparing an environmentally friendly high-strength car roof includes the following steps: stacking the materials in sequence, hot pressing at 130°C, molding pressure of 8MPa, molding time of 10s, cooling and setting for 10s, and cutting.

[0039] Example 2

[0040] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt.

[0041] The first and second toughening fiber felts are both made of toughening fibers with a diameter of 3-10 μm; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0042] The polyurethane substrate has a thickness of 15mm, the toughening fiber felt has a thickness of 0.2mm, and the first, second, third, and fourth adhesive layers all have a thickness of 0.2mm.

[0043] The polyurethane substrate was prepared by the following specific operation: 60 kg of polyether polyol with a molecular weight of 3000 and a hydroxyl value of 28 mg KOH / g was continuously stirred. During the stirring process, 1 kg of triethanolamine, 0.1 kg of dibutyltin dilaurate, 2 kg of Evonik O-500, 2 kg of foaming agent HFC-245fa, 10 kg of water, 2 kg of silicone oil, and 15 kg of activated carbon fiber were added in sequence. After the addition was complete, the mixture was stirred at 15°C for 20 min. Then, 50 kg of toluene diisocyanate was added and stirred evenly at 10°C. The mixture was then poured into a mold for curing, demolded, and cooled.

[0044] The toughening fiber is prepared by the following specific operation: 20 kg of ultra-high molecular weight polyethylene with a molecular weight of 4 million is added to 60 kg of decahydronaphthalene and stirred at 95℃ for 2 hours. Then, 5 kg of silicate cement with a particle size of 5-15 μm and 2 kg of chitosan are added and stirred evenly. The mixture is then extruded from the spinneret orifice, cooled, cured, and dried to remove the solvent.

[0045] The composite ethylene-vinyl acetate copolymer is prepared by the following specific operation: 60 kg of ethylene-vinyl acetate copolymer, 3 kg of carboxyl-terminated polyamide amine, 2 kg of nano titanium dioxide, 15 kg of activated carbon, 2 kg of pentaerythritol tetraacrylate, 2 kg of tert-butyl peroxide-2-ethylhexyl ester, and 2 kg of antioxidant are mixed evenly and fed into an extruder and extruded at a temperature of 220℃.

[0046] The above-mentioned method for preparing an environmentally friendly high-strength car roof includes the following steps: stacking the materials in sequence, hot pressing at 150°C, molding pressure of 10MPa, molding time of 20s, cooling and setting for 20s, and cutting.

[0047] Example 3

[0048] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt.

[0049] The first and second toughening fiber felts are both made of toughening fibers with a diameter of 3-10 μm; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0050] The polyurethane substrate has a thickness of 11 mm, the toughening fiber felt has a thickness of 0.18 mm, and the first, second, third, and fourth adhesive layers each have a thickness of 0.13 mm.

[0051] The polyurethane substrate was prepared using the following specific steps: 50 kg of polyether polyol with a molecular weight of 3000 and a hydroxyl value of 28 mg KOH / g was continuously stirred. During the stirring process, 0.2 kg of triethanolamine, 0.07 kg of dibutyltin dilaurate, 1.3 kg of Mester AK9905, 1.8 kg of foaming agent HFC-245fa, 7 kg of water, 1.7 kg of silicone oil, and 8 kg of activated carbon fiber were added sequentially. After all the additions were complete, the mixture was stirred at 12°C for 12 minutes. Then, 45 kg of toluene diisocyanate was added, and the mixture was stirred evenly at 6°C. The mixture was then poured into a mold for curing, demolded, and cooled.

[0052] The toughening fiber is prepared by the following specific operation: 18 kg of ultra-high molecular weight polyethylene with a molecular weight of 3.3 million is added to 45 kg of decahydronaphthalene and stirred at 94℃ for 80 min. 4 kg of silicate cement with a particle size of 5-15 μm and 1.3 kg of chitosan are added and stirred evenly. The mixture is then extruded from the spinneret orifice, cooled, cured, and dried to remove the solvent.

[0053] The composite ethylene-vinyl acetate copolymer was prepared by the following specific operation: 55 kg of ethylene-vinyl acetate copolymer, 1.5 kg of carboxyl-terminated polyamide amine, 1.7 kg of nano titanium dioxide, 8 kg of activated carbon, 1.7 kg of pentaerythritol tetraacrylate, 1.2 kg of tert-butyl peroxide-2-ethylhexyl ester, and 1.7 kg of antioxidant were mixed evenly and fed into an extruder and extruded at a temperature of 190°C.

[0054] The above-mentioned method for preparing an environmentally friendly high-strength automotive roof includes the following steps: stacking the materials in sequence, hot-pressing at 145°C with a molding pressure of 7MPa and a molding time of 18s, cooling and setting for 13s, and then cutting.

[0055] Example 4

[0056] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt.

[0057] The first and second toughening fiber felts are both made of toughening fibers with a diameter of 3-10 μm; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0058] The polyurethane substrate has a thickness of 13mm, the toughening fiber felt has a thickness of 0.12mm, and the first, second, third, and fourth adhesive layers each have a thickness of 0.17mm.

[0059] The polyurethane substrate was prepared using the following specific steps: 40 kg of polyether polyol with a molecular weight of 3000 and a hydroxyl value of 28 mg KOH / g was continuously stirred. During the stirring process, 0.8 kg of triethanolamine, 0.03 kg of dibutyltin dilaurate, 1.7 kg of Evonik O-500, 1.2 kg of foaming agent HFC-245fa, 9 kg of water, 1.3 kg of silicone oil, and 12 kg of activated carbon fiber were added sequentially. After all the additions were complete, the mixture was stirred at 8°C for 18 minutes. Then, 35 kg of toluene diisocyanate was added, and the mixture was stirred evenly at 9°C. The mixture was then poured into a mold for curing, demolded, and cooled.

[0060] The pore-opening agent is either Evonik O-501 or Mistex AK9905.

[0061] The toughening fiber is prepared by the following specific operation: 12 kg of ultra-high molecular weight polyethylene with a molecular weight of 3.7 million is added to 55 kg of decahydronaphthalene and stirred at 92℃ for 100 min. Then, 2 kg of silicate cement with a particle size of 5-15 μm and 1.7 kg of chitosan are added and stirred evenly. The mixture is then extruded from the spinneret orifice, cooled, cured, and dried to remove the solvent.

[0062] The composite ethylene-vinyl acetate copolymer was prepared by the following specific operation: 45 kg of ethylene-vinyl acetate copolymer, 2.5 kg of carboxyl-terminated polyamide amine, 1.3 kg of nano titanium dioxide, 12 kg of activated carbon, 1.3 kg of pentaerythritol tetraacrylate, 1.8 kg of tert-butylperoxide-2-ethylhexyl ester, and 1.3 kg of antioxidant were mixed evenly and fed into an extruder and extruded at a temperature of 210℃.

[0063] The above-mentioned method for preparing an environmentally friendly high-strength car roof includes the following steps: stacking the materials in sequence, hot-pressing at 135°C with a molding pressure of 9MPa and a molding time of 12s, cooling and setting for 17s, and then cutting.

[0064] Example 5

[0065] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt.

[0066] The first and second toughening fiber felts are both made of toughening fibers with a diameter of 3-10 μm; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0067] The polyurethane substrate has a thickness of 12mm, the toughening fiber felt has a thickness of 0.15mm, and the first, second, third, and fourth adhesive layers all have a thickness of 0.15mm.

[0068] The polyurethane substrate was prepared using the following specific steps: 45 kg of polyether polyol with a molecular weight of 3000 and a hydroxyl value of 28 mg KOH / g was continuously stirred. During the stirring process, 0.5 kg of triethanolamine, 0.05 kg of dibutyltin dilaurate, 1.5 kg of Mist AK9905, 1.5 kg of foaming agent HFC-245fa, 8 kg of water, 1.5 kg of silicone oil, and 10 kg of activated carbon fiber were added sequentially. After all the additions were complete, the mixture was stirred at 10°C for 15 minutes. Then, 40 kg of toluene diisocyanate was added, and the mixture was stirred evenly at 8°C. The mixture was then poured into a mold for curing, demolded, and cooled.

[0069] The toughening fiber is prepared by the following specific operation: 15 kg of ultra-high molecular weight polyethylene with a molecular weight of 3.5 million is added to 50 kg of decahydronaphthalene, stirred at 93℃ for 90 min, 3 kg of silicate cement with a particle size of 5-15 μm and 1.5 kg of chitosan are added and stirred evenly, extruded from the spinneret holes, cooled, cured and dried to remove solvent.

[0070] The composite ethylene-vinyl acetate copolymer is prepared by the following specific operation: 50 kg of ethylene-vinyl acetate copolymer, 2 kg of carboxyl-terminated polyamide amine, 1.5 kg of nano titanium dioxide, 10 kg of activated carbon, 1.5 kg of pentaerythritol tetraacrylate, 1.5 kg of tert-butylperoxide-2-ethylhexyl ester, and 1.5 kg of antioxidant are mixed evenly and fed into an extruder and extruded at a temperature of 200℃.

[0071] The above-mentioned method for preparing an environmentally friendly high-strength car roof includes the following steps: stacking the materials in sequence, hot-pressing at 140°C, molding pressure of 8MPa, molding time of 15s, cooling and setting for 15s, and cutting.

[0072] Comparative Example 1

[0073] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first glass fiber mat bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first glass fiber mat, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second glass fiber mat bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second glass fiber mat.

[0074] Both the first and second glass fiber mats are made of glass fibers with a diameter of 3-10 μm; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0075] The polyurethane substrate has a thickness of 12mm, the first and second glass fiber mats each have a thickness of 0.15mm, and the first, second, third, and fourth adhesive layers each have a thickness of 0.15mm.

[0076] The polyurethane substrate was prepared using the following specific steps: 45 kg of polyether polyol with a molecular weight of 3000 and a hydroxyl value of 28 mg KOH / g was continuously stirred. During the stirring process, 0.5 kg of triethanolamine, 0.05 kg of dibutyltin dilaurate, 1.5 kg of Mist AK9905, 1.5 kg of foaming agent HFC-245fa, 8 kg of water, 1.5 kg of silicone oil, and 10 kg of activated carbon fiber were added sequentially. After all the additions were complete, the mixture was stirred at 10°C for 15 minutes. Then, 40 kg of toluene diisocyanate was added, and the mixture was stirred evenly at 8°C. The mixture was then poured into a mold for curing, demolded, and cooled.

[0077] The composite ethylene-vinyl acetate copolymer is prepared by the following specific operation: 50 kg of ethylene-vinyl acetate copolymer, 2 kg of carboxyl-terminated polyamide amine, 1.5 kg of nano titanium dioxide, 10 kg of activated carbon, 1.5 kg of pentaerythritol tetraacrylate, 1.5 kg of tert-butylperoxide-2-ethylhexyl ester, and 1.5 kg of antioxidant are mixed evenly and fed into an extruder and extruded at a temperature of 200℃.

[0078] The above-mentioned method for preparing an environmentally friendly high-strength car roof includes the following steps: stacking the materials in sequence, hot-pressing at 140°C, molding pressure of 8MPa, molding time of 15s, cooling and setting for 15s, and cutting.

[0079] Comparative Example 2

[0080] An environmentally friendly, high-strength car roof comprises, from bottom to top: a non-woven fabric layer, a first adhesive layer cast on the surface of the non-woven fabric layer, a first toughening fiber felt bonded to the surface of the first adhesive layer, a second adhesive layer cast on the surface of the first toughening fiber felt, a polyurethane substrate bonded to the surface of the second adhesive layer, a third adhesive layer cast on the surface of the polyurethane substrate, a second toughening fiber felt bonded to the surface of the third adhesive layer, and a fourth adhesive layer cast on the surface of the second toughening fiber felt.

[0081] The first and second toughening fiber felts are both made of toughening fibers with a diameter of 3-10 μm; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer.

[0082] The polyurethane substrate has a thickness of 12mm, the toughening fiber felt has a thickness of 0.15mm, and the first, second, third, and fourth adhesive layers all have a thickness of 0.15mm.

[0083] The polyurethane substrate was prepared using the following specific steps: 45 kg of polyether polyol with a molecular weight of 3000 and a hydroxyl value of 28 mg KOH / g was continuously stirred. During the stirring process, 0.5 kg of triethanolamine, 0.05 kg of dibutyltin dilaurate, 1.5 kg of Mist AK9905, 1.5 kg of foaming agent HFC-245fa, 8 kg of water, 1.5 kg of silicone oil, and 10 kg of activated carbon fiber were added sequentially. After all the additions were complete, the mixture was stirred at 10°C for 15 minutes. Then, 40 kg of toluene diisocyanate was added, and the mixture was stirred evenly at 8°C. The mixture was then poured into a mold for curing, demolded, and cooled.

[0084] The toughening fiber is prepared by the following specific operation: 15 kg of ultra-high molecular weight polyethylene with a molecular weight of 3.5 million is added to 50 kg of decahydronaphthalene, stirred at 93℃ for 90 min, 3 kg of silicate cement with a particle size of 5-15 μm is added and mixed evenly, and then extruded from the spinneret orifice, cooled, cured, and dried to remove the solvent.

[0085] The composite ethylene-vinyl acetate copolymer is prepared by the following specific operation: 50 kg of ethylene-vinyl acetate copolymer, 2 kg of carboxyl-terminated polyamide amine, 1.5 kg of nano titanium dioxide, 10 kg of activated carbon, 1.5 kg of pentaerythritol tetraacrylate, 1.5 kg of tert-butylperoxide-2-ethylhexyl ester, and 1.5 kg of antioxidant are mixed evenly and fed into an extruder and extruded at a temperature of 200℃.

[0086] The above-mentioned method for preparing an environmentally friendly high-strength car roof includes the following steps: stacking the materials in sequence, hot-pressing at 140°C, molding pressure of 8MPa, molding time of 15s, cooling and setting for 15s, and cutting.

[0087] The tensile strength and elongation at break of the automotive headliners obtained in Example 5 and Comparative Examples 1-2 were determined according to GB / T 6344-2008 "Determination of Tensile Strength and Elongation at Break of Flexible Foam Polymer Materials". The tear strength of the automotive headliners obtained in Example 5 and Comparative Examples 1-2 was determined according to GB / T 10808-2006 "Determination of Tear Strength of Porous Polymer Materials". The compression set of the automotive headliners obtained in Example 5 and Comparative Examples 1-2 was tested according to GB / T 6669-2008 "Determination of Compression Set of Flexible Foam Polymer Materials".

[0088] like Figure 1 and Figure 2 As shown, the car roof obtained in Example 5 has the highest tensile strength, tear strength and compression set, which are superior to Comparative Examples 1-2 (P<0.05).

[0089] The applicant believes that this invention uses ultra-high molecular weight polyethylene, silicate cement, and chitosan to create a composite spinning process, resulting in toughened fiber felt that, compared to glass fiber, has better adhesion and bonding with the composite ethylene-vinyl acetate copolymer. After high-temperature pressing, it not only has good rigidity but also does not crack during use, while exhibiting high tear resistance. Furthermore, this invention does not use glass fiber, resulting in high tear resistance and effectively avoiding the potential harm to production personnel from fine particles generated during processing. This significantly improves the structural strength and performance of the automotive roof while enhancing quality. The combination of toughened fiber felt and polyurethane substrate simultaneously achieves lightweighting and environmental friendliness, addressing the weaknesses of existing automotive roof materials and making it an ideal alternative material for automotive roofs.

[0090] The car roofs obtained in Example 5 and Comparative Examples 1-2 were installed in vehicles of the same brand and model. The performance of the car roofs was tested according to GB / T27630-2011 "Guidelines for Air Quality Evaluation in Passenger Cars" and HJ / T 400-2007 "Sampling and Determination Methods for Volatile Organic Compounds and Aldehydes and Ketones in Vehicle Interiors". The test structure is shown in the table below. In the table, "ND" indicates that the substance was not detected.

[0091]

[0092] The applicant believes that this is because the addition of nano-titanium dioxide and activated carbon to the composite ethylene-vinyl acetate copolymer in Examples 5 and Comparative Examples 1-2 enables the roof to adsorb and degrade aldehydes, thereby reducing the VOC value inside the car during use, resulting in good environmental protection and keeping the air inside the car fresh.

[0093] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An environmentally friendly, high-strength automotive roof, characterized in that, From bottom to top, this includes: The nonwoven fabric layer, the first adhesive layer cast on the surface of the nonwoven fabric layer, the first toughening fiber felt bonded to the surface of the first adhesive layer, the second adhesive layer cast on the surface of the first toughening fiber felt, the polyurethane substrate bonded to the surface of the second adhesive layer, the third adhesive layer cast on the surface of the polyurethane substrate, the second toughening fiber felt bonded to the surface of the third adhesive layer, and the fourth adhesive layer cast on the surface of the second toughening fiber felt; the layers are stacked in sequence and then hot-pressed to form the product. The first and second toughening fiber felts are both made of toughening fibers; while the first, second, third, and fourth adhesive layers are all made of composite ethylene-vinyl acetate copolymer. The polyurethane substrate is prepared by the following specific operation: Polyether polyol is continuously stirred, and triethanolamine, catalyst, pore-opening agent, foaming agent, water, silicone oil and activated carbon fiber are added in sequence during the stirring process. After the addition is complete, the mixture is stirred at 5-15℃ for 10-20 minutes. Then toluene diisocyanate is added, the temperature is adjusted to 5-10℃ and stirred evenly, cured and cooled. The toughening fiber is prepared by the following specific operation: ultra-high molecular weight polyethylene is added to decahydronaphthalene and stirred at 90-95℃ for 1-2 hours. Silicate cement and chitosan are added and stirred evenly. The mixture is then extruded from the spinneret holes, cooled, cured, and dried to remove the solvent. The composite ethylene-vinyl acetate copolymer is prepared by the following specific operation: the ethylene-vinyl acetate copolymer, carboxyl-terminated polyamide amine, nano titanium dioxide, activated carbon, pentaerythritol tetraacrylate, tert-butyl peroxide-2-ethylhexyl ester, and antioxidant are mixed evenly and extruded at 180-220℃.

2. The environmentally friendly high-strength automotive roof according to claim 1, characterized in that, The polyether polyol has a molecular weight of 2500-3500 and a hydroxyl value of 25-30 mg KOH / g; the catalyst is dibutyltin dilaurate; the foaming agent is HFC-245fa; and the cell opener is at least one of Evonik O-501, Evonik O-500, and Mistex AK9905.

3. The environmentally friendly high-strength automotive roof according to claim 1, characterized in that, The mass ratio of polyether polyol, triethanolamine, catalyst, cell opener, foaming agent, water, silicone oil, activated carbon fiber, and toluene diisocyanate is 30-60:0.1-1:0.01-0.1:1-2:1-2:5-10:1-2:5-15:30-50.

4. The environmentally friendly high-strength automotive roof according to claim 1, characterized in that, The diameter of the toughening fibers is 3-10 μm.

5. The environmentally friendly high-strength automotive roof according to claim 1, characterized in that, Ultra-high molecular weight polyethylene has a molecular weight of 3-4 million, and silicate cement has a particle size of 5-15 μm.

6. The environmentally friendly high-strength automotive roof according to claim 1, characterized in that, The mass ratio of ultra-high molecular weight polyethylene, silicate cement, and chitosan is 10-20:1-5:1-2.

7. The environmentally friendly high-strength automotive roof according to claim 1, characterized in that, The mass ratio of ethylene-vinyl acetate copolymer, carboxyl-terminated polyamide amine, nano titanium dioxide, activated carbon, pentaerythritol tetraacrylate, tert-butyl peroxide-2-ethylhexyl ester, and antioxidant is 40-60:1-3:1-2:5-15:1-2:1-2:1-2.

8. A method for preparing an environmentally friendly high-strength automotive roof as described in any one of claims 1-7, characterized in that, The process includes the following steps: stacking each layer in sequence, hot pressing at 130-150℃, forming pressure of 8-10MPa, forming time of 10-20s, and cooling and setting for 10-20s.

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