Process for the preparation of low odor low voc composite skins

Abstract

The present application relates to a kind of preparation methods of low odor low VOC composite skin, mainly solve the problem of existing technology in the composite skin of automobile interior smell, VOC is high.The present application is by using a kind of preparation method of low odor low VOC composite skin, including the following steps:1) gas and air after drying respectively into gas buffer tank, air buffer tank;2) from the gas buffer tank of gas after pressure control into mixer;3) from the air buffer tank of air after pressure control into mixer;4) control gas and air flow rate adjust the volume ratio of gas and air in mixer, obtain uniform mixed gas;5) mixed gas enters the gas purification device with molecular sieve type adsorbent, obtain purified mixed gas;6) purified mixed gas enters flame compound machine and carries out flame compound, obtain the technical scheme of low odor low VOC composite skin, preferably solve the problem, can be used in the industrial production of automobile interior composite skin.

Description

Technical Field

[0001] This invention relates to the field of automotive interior materials, and in particular to a method for preparing a low-odor, low-VOC composite skin. Background Technology

[0002] Composite materials used in automotive interiors are typically produced using a flame lamination process. In this process, a flame rapidly burns the surface of a sponge, bonding the sponge or other thermoplastic materials to leather, fabric, or other materials. The flame lamination process inevitably requires the use of fuel gas, such as liquefied petroleum gas (LPG). However, fuel gas typically has a certain purity at the factory and contains some small-molecule impurities. When ignited or heated, these impurities can generate volatile harmful substances. Especially when the quality of the purchased gas fluctuates, the varying levels of impurities can have an uncontrollable impact on the odor, VOCs, and other quality aspects of the flame-laminated product.

[0003] The main components of commonly used liquefied petroleum gas (LPG) are propane, propylene, butane, and butene. It also leaves behind some volatile small molecules, such as aromatic hydrocarbons like benzene, toluene, xylene, ethylbenzene, trimethylbenzene, naphthalene, anthracene, and oxalool; sulfides like hydrogen sulfide, sulfur dioxide, thiols, thioethers, thiophene, methyl mercaptan, and methyl sulfide; as well as ammonia and cyanide. These substances volatilize during the flame lamination process, contaminating the composite product. Furthermore, materials like sponges and leather themselves have strong, irritating odors, resulting in a final composite product with a strong odor and high VOC content, failing to meet customer requirements and potentially causing harm to the human body with prolonged exposure. Therefore, developing low-odor, low-VOC composite skins is of significant practical importance. Currently, the main approach to developing low-odor, low-VOC composite skins is to reduce the odor of raw materials, such as using low-odor sponges and leather.

[0004] Chinese patent CN109353085A discloses a low-odor, low-VOC automotive fabric and its manufacturing method. The manufacturing materials include a fabric, a sponge, a base fabric, and auxiliary materials. The auxiliary materials are composed of 1-2 parts by weight of light stabilizer, 2-3 parts by weight of odor absorber, 0.5-1 parts by weight of heat stabilizer, 2-3 parts by weight of processing aid, 1.5-2 parts by weight of reactive amine catalyst, and 100 parts by weight of water. The addition of auxiliary materials prevents the automotive fabric from emitting harmful VOC odors on a large scale when exposed to strong light, and the emitted VOCs are also absorbed and catalyzed by the reactive amine catalyst, thus reducing the odor and VOCs of the composite fabric. However, this method requires preparing a solution to wet the composite fabric and then drying it, which is cumbersome and introduces a large number of chemical reagents, which is not environmentally friendly.

[0005] PV3900-2000 is a commonly used odor testing standard. Odor evaluation adopts a 6-level evaluation standard: Level 1 indicates no odor, Level 2 indicates odor but not bothersome, Level 3 indicates noticeable odor but still not bothersome, Level 4 indicates bothersome odor, Level 5 indicates strong bothersome odor, and Level 6 indicates intolerable. The odor evaluation is conducted by 3 to 5 people. The evaluation results can be described in half-levels, and the average value is taken as the final odor level result. The lower the level, the weaker the odor. Summary of the Invention

[0006] The technical problem to be solved by the present invention is that the composite skin used in automotive interiors has a strong odor and high VOC content in the prior art. The present invention provides a method for preparing a low-odor, low-VOC composite skin, which has the advantages of low odor and low VOC content.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a method for preparing a low-odor, low-VOC composite skin, comprising the following steps:

[0008] 1) After being dried, the fuel gas and air enter the fuel gas buffer tank and air buffer tank respectively;

[0009] 2) The gas from the gas buffer tank enters the mixer after being controlled by the gas pressure;

[0010] 3) The air coming out of the air buffer tank enters the mixer after being controlled by air pressure;

[0011] 4) Control the flow rate of gas and air to adjust the volume ratio of gas and air in the mixer to obtain a uniform gas mixture;

[0012] 5) The mixed gas enters a gas purification device filled with molecular sieve adsorbent, where aromatics, sulfides, ammonia and cyanide in the mixed gas are adsorbed and removed to obtain purified mixed gas.

[0013] 6) The purified mixed gas enters the flame laminating machine, and the sponge is ignited at the burner to perform flame lamination, resulting in a low-odor, low-VOC composite skin.

[0014] Furthermore, the pressure of both the gas and air is controlled at 4.0–8.0 kPa, and the volume ratio of gas to air in the mixer is 45–120:30.

[0015] Furthermore, the volume ratio of gas to air in the mixer is 60-80:30.

[0016] Furthermore, the gas device for flame recombining includes a gas chamber 1, an air source 2, an air dryer 3, a gas dryer 3', a gas buffer tank 4, an air buffer tank 5, a mixer 6, a gas purification device 7, and a flame recombining machine 8; wherein, the gas outlet of the gas chamber 1 is connected to the air inlet of the gas buffer tank 4 through the gas dryer 3'; the gas outlet of the air source 2 is connected to the air inlet of the air buffer tank 5 through the air dryer 3; the gas outlet of the gas buffer tank 4 is connected to the air inlet of the mixer 6 through a gas pipeline equipped with a gas pressure control device; the air buffer tank 6... The outlet of the flushing tank 5 is connected to the inlet of the mixer 6 via an air pipeline equipped with an air pressure control device; the outlet of the mixer 6 is connected to the bottom inlet of the gas purification device 7, which contains a molecular sieve adsorbent; the top outlet of the gas purification device 7 is connected to the flame composite machine 8 via a mixed gas pipeline equipped with a mixed gas pressure control device; the molecular sieve adsorbent is selected from at least one of the following: lanthanum-loaded ZSM-5 / mordenite symbiotic molecular sieve, copper-loaded MCM-22 molecular sieve, or copper and zinc-loaded MCM-49 molecular sieve.

[0017] Furthermore, the gas device for flame composite also includes a pressure control cabinet 10 and a computer 12; the gas pressure control device, air pressure control device and mixed gas pressure control device are respectively connected to the pressure control cabinet 10, and the pressure control cabinet 10 is connected to the computer 12.

[0018] Furthermore, the gas pressure control device consists of a first remote pressure gauge 4-1 and a first valve 4-2 with interlocked control; the air pressure control device consists of a second remote pressure gauge 5-1 and a second valve 5-2 with interlocked control; and the mixed gas pressure control device consists of a third remote pressure gauge 7-1 and a third valve 7-2 with interlocked control.

[0019] Furthermore, a gas flow controller 4-3 is provided on the pipeline between the gas buffer tank 4 and the mixer 6; an air flow controller 5-3 is provided on the pipeline between the air buffer tank 5 and the mixer 6.

[0020] Furthermore, the flame-combined gas device also includes a pressure alarm 11 connected to the pressure control cabinet 10.

[0021] Furthermore, the flame-combining gas device also includes an exhaust gas treatment device 9.

[0022] Furthermore, a first manual valve 1-1 is provided on the pipeline between the gas room 1 and the gas buffer tank 4, and a second manual valve 7-3 and a one-way valve 7-4 are provided on the mixed gas pipeline.

[0023] Furthermore, a gas venting pipe is provided on the mixed gas pipeline between the one-way valve 7-4 and the flame compounding machine 8. A third manual valve 7-5 is provided on the gas venting pipe, and the end of the gas venting pipe is connected to the exhaust gas treatment device 9.

[0024] Furthermore, the first valve 4-2, the second valve 5-2, and the third valve 7-2 are all solenoid valves, and the first manual valve 1-1, the second manual valve 7-3, and the third manual valve 7-5 are all ball valves.

[0025] Furthermore, the lanthanum-loaded ZSM-5 / mordenite symbiotic molecular sieve contains 0.2-0.8% lanthanum by mass and a SiO2 / Al2O3 molar ratio of 15-30; the copper-loaded MCM-22 molecular sieve contains 0.1-1.0% copper by mass and a SiO2 / Al2O3 molar ratio of 80-110; the copper- and zinc-loaded MCM-49 molecular sieve contains 0.2-0.5% copper by mass, 0.3-0.8% zinc by mass and a SiO2 / Al2O3 molar ratio of 15-25.

[0026] Furthermore, the air dryer 3 and the gas dryer 3' are filled with silica gel adsorbent.

[0027] Furthermore, the pressures of the gas pipeline, air pipeline, and mixed gas pipeline are equal.

[0028] The method for preparing a low-odor, low-VOC composite skin provided by this invention involves adding a gas purification device to a conventional gas combustion device. This device thoroughly adsorbs and purifies the gas and air, significantly reducing the content of residual small-molecule substances in the raw material gas and the content of volatile organic compounds formed after the combustion of small-molecule substances in the flame composite process. This purification of the raw material gas at its source reduces the odor and VOC content of the composite product, lowering the odor rating from 4.5 to 3.0. The VOC test results for a 1 cubic meter container show TVOC < 200 μg / m³. 3 Benzene is ND, toluene <10μg / m 3 Ethylbenzene < 5 μg / m 3 Xylene <15 μg / m 3 Styrene is ND, formaldehyde <6μg / m³ 3 Acetaldehyde < 30 μg / m 3 Acrylaldehyde is an ND compound. The composite product has the advantages of low odor and low VOC content, which improves the quality and market competitiveness of flame composite products and achieves good technical results. Attached Figure Description

[0029] Appendix Figure 1This is a schematic diagram of the structure of the flame-combining gas device used in this invention.

[0030] Appendix Figure 1 In the diagram, 1 is the gas room, 1-1 is the first manual valve, 2 is the air source, 3 is the air dryer, 3' is the gas dryer, 4 is the gas buffer tank, 4-1 is the first remote pressure gauge, 4-2 is the first valve, 4-3 is the gas flow controller, 5 is the air buffer tank, 5-1 is the second remote pressure gauge, 5-2 is the second valve, 5-3 is the air flow controller, 6 is the mixer, 7 is the gas purification device, 7-1 is the third remote pressure gauge, 7-2 is the third valve, 7-3 is the second manual valve, 7-4 is the check valve, 7-5 is the third manual valve, 8 is the flame combining machine, 9 is the exhaust gas treatment device, 10 is the pressure control cabinet, 11 is the pressure alarm, and 12 is the computer. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0032]

Example 1

[0033] A method for preparing a low-odor, low-VOC composite skin includes the following steps:

[0034] 1) After being dried, the fuel gas and air enter the fuel gas buffer tank and air buffer tank respectively;

[0035] 2) The gas and air from the gas buffer tank and air buffer tank enter the mixer after being controlled by pressure and flow respectively. The pressure of both gas and air is 6.0 kPa.

[0036] 3) Adjust the flow rate to make the volume ratio of gas and air in the mixer 70:30, forming a gas mixture with a uniform ratio of gas and air;

[0037] 4) The mixed gas enters a gas purification device filled with molecular sieve adsorbent, where aromatics, sulfides, ammonia and cyanide in the mixed gas are adsorbed and removed to obtain purified mixed gas.

[0038] 5) The purified mixed gas enters the flame laminating machine. The flame laminating process parameters are set as follows: upper gap 2.5mm, lower gap 2.0mm, upper flame port distance 50mm, lower flame port distance 60mm, upper flame port mixed airflow index 75%, lower flame port mixed airflow index 60%, main unit speed 20m / min, flame temperature range 800~1000℃; the temperature detection device automatically detects the flame temperature of the upper and lower flame ports as 820℃ and 822℃ respectively. The sponge is burned and melted at the upper flame port to form an adhesive film on one side, and the sponge and the base fabric are bonded to form a composite semi-finished product.

[0039] 6) Burn and melt the sponge on the other side of the composite semi-finished product at the lower burner to form an adhesive film. The composite semi-finished product and PVC leather are bonded together through the adhesive film to obtain a low-odor, low-VOC composite skin.

[0040] 7) The performance of the low-odor, low-VOC composite skin was tested, and the results are shown in Table 2.

[0041] The flame combining gas device used in this embodiment includes a gas chamber 1, an air source 2, an air dryer 3, a gas dryer 3', a gas buffer tank 4, an air buffer tank 5, a mixer 6, a gas purification device 7, a flame combining machine 8, an exhaust gas treatment device 9, a pressure control cabinet 10, a pressure alarm 11, and a computer 12. Both the gas buffer tank 4 and the air buffer tank 5 are equipped with air inlets and outlets. The gas chamber 1 is connected to the air inlet of the gas buffer tank 4 via the gas dryer 3', and the outlet of the gas buffer tank 4 is connected to the air inlet of the mixer 6 via a gas pipe. The gas pipe is equipped with a first remote control for interlocking. Pressure gauge 4-1 and first valve 4-2; air source 2 is connected to the air inlet of air buffer tank 5 through air dryer 3, and the air outlet of air buffer tank 5 is connected to the air inlet of mixer 6 through air pipeline. The air pipeline is equipped with a second remote pressure gauge 5-1 and a second valve 5-2 with interlocking control; both air dryer 3 and gas dryer 3' are filled with silica gel adsorbent to remove moisture from the pipeline; a gas flow controller 4-3 is also installed on the pipeline between gas buffer tank 4 and mixer 6; an air flow controller 5-3 is also installed on the pipeline between air buffer tank 5 and mixer 6; the gas purification device 7 is filled with... The ZSM-5 / mordenite symbiotic molecular sieve, loaded with 0.5% lanthanum, has a SiO2 / Al2O3 molar ratio of 20 and a ZSM-5 to mordenite mass ratio of 87:13. It can simultaneously adsorb and remove aromatics, sulfides, ammonia, and cyanides from fuel gas and air. The gas purification device 7 has an inlet at the bottom and an outlet at the top. The inlet is connected to the outlet of the mixer 6, and the outlet is connected to the flame combining machine 8 via a mixed gas pipeline. The mixed gas pipeline is equipped with a third remote pressure gauge 7-1, a third valve 7-2, a mixed gas flow controller, a second manual valve 7-3, and a single... The system is interlocked with valve 7-4, the third remote pressure gauge 7-1, and the third valve 7-2; a gas vent pipe is provided on the mixed gas pipeline between check valve 7-4 and flame composite machine 8, and a third manual valve 7-5 is provided on the gas vent pipe. The end of the gas vent pipe is connected to the exhaust gas treatment device 9; flame composite machine 8 and exhaust gas treatment device 9 are connected; pressure control cabinet 10 is connected to computer 12; the first remote pressure gauge 4-1, the first valve 4-2, the second remote pressure gauge 5-1, the second valve 5-2, the third remote pressure gauge 7-1, and the third valve 7-2 are each independently connected to pressure control cabinet 10 via transmission lines;

[0042] The flame composite machine 8 is equipped with a linear gas burner, pressure roller, roller shaft, conveying device, temperature detection device, thickness detection device, and upper and lower burners. The gas room 1 uses liquefied petroleum gas, the air source 2 is a fan, the first valve 4-2, the second valve 5-2 and the third valve 7-2 are solenoid valves, and the first manual valve 1-1, the second manual valve 7-3 and the third manual valve 7-5 are ball valves. When the solenoid valve malfunctions and cannot be effectively controlled, the ball valves are manually opened or closed to prevent abnormal gas pipeline pressure.

[0043] In this embodiment, the impurity content of the gas at the gas room outlet, the air at the air source outlet, and the mixed gas at the gas purification device outlet were sampled and tested. The results are as follows:

[0044] The liquefied petroleum gas at the gas station outlet contains: benzene 120 ppm, toluene 62 ppm, ethylbenzene 62 ppm, naphthalene 125 ppm, hydrogen sulfide sulfur 19 ppm, mercaptan sulfur 328 ppm, and carbonyl sulfur 19 ppm.

[0045] At the air source outlet, the following concentrations of substances were present in the air: benzene 60 ppm, toluene 25 ppm, ethylbenzene 28 ppm, formaldehyde 19 ppm, acetaldehyde 16 ppm, and acrolein 10 ppm.

[0046] The mixed gas at the outlet of the gas purification device contained the following components: benzene 15 ppm, toluene 8 ppm, ethylbenzene 6 ppm, naphthalene 6 ppm, hydrogen sulfide sulfur 0.5 ppm, mercaptan sulfur 8 ppm, carbonyl sulfur 3 ppm, formaldehyde 2.1 ppm, acetaldehyde 0.9 ppm, and acrolein was not detected.

[0047]

Example 2

[0048] Example 2 used the same preparation method and flame composite gas device as Example 1. The only difference was that the molecular sieve adsorbent filled in the gas purification device was different and the specific process parameters of flame composite were different, as shown in Table 1. The performance of the obtained low-odor, low-VOC composite skin was tested, and the results are shown in Table 2.

[0049] In this embodiment, the impurity content of the gas at the gas station outlet, the air at the air source outlet, and the mixed gas at the gas purification device outlet were sampled and tested. The results are as follows:

[0050] The liquefied petroleum gas at the gas station outlet contains: benzene 136 ppm, toluene 58 ppm, ethylbenzene 65 ppm, naphthalene 119 ppm, hydrogen sulfide sulfur 15 ppm, mercaptan sulfur 302 ppm, and carbonyl sulfur 15 ppm.

[0051] At the air source outlet, the following concentrations of substances were found in the air: benzene 61 ppm, toluene 19 ppm, ethylbenzene 33 ppm, formaldehyde 24 ppm, acetaldehyde 12 ppm, and acrolein 11 ppm.

[0052] The mixed gas at the outlet of the gas purification device contained the following components: benzene 12 ppm, toluene 6 ppm, ethylbenzene 7.5 ppm, naphthalene 2 ppm, hydrogen sulfide sulfur 2 ppm, mercaptan sulfur 6 ppm, carbonyl sulfur 5 ppm, formaldehyde 1 ppm, acetaldehyde 0.5 ppm, and acrolein was not detected.

[0053]

Example 3

[0054] Example 3 used the same preparation method and flame composite gas device as Example 1. The only difference was that the molecular sieve adsorbent filled in the gas purification device was different and the specific process parameters of flame composite were different, as shown in Table 1. The performance of the obtained low-odor, low-VOC composite skin was tested, and the results are shown in Table 2.

[0055] In this embodiment, the impurity content of the gas at the gas station outlet, the air at the air source outlet, and the mixed gas at the gas purification device outlet were sampled and tested. The results are as follows:

[0056] The liquefied petroleum gas at the gas station outlet contains: benzene 105 ppm, toluene 54 ppm, ethylbenzene 59 ppm, naphthalene 128 ppm, hydrogen sulfide sulfur 14 ppm, mercaptan sulfur 289 ppm, and carbonyl sulfur 12 ppm.

[0057] At the air source outlet, the following concentrations of substances were present in the air: benzene 62 ppm, toluene 27 ppm, ethylbenzene 23 ppm, formaldehyde 20 ppm, acetaldehyde 9 ppm, and acrolein 8 ppm.

[0058] The mixed gas at the outlet of the gas purification device contained the following: benzene 6 ppm, toluene 5 ppm, ethylbenzene 7 ppm, naphthalene 3 ppm, hydrogen sulfide sulfur 2 ppm, mercaptan sulfur 5 ppm, carbonyl sulfur 2 ppm, formaldehyde 1.8 ppm, acetaldehyde and acrolein were not detected.

[0059]

Example 4

[0060] Example 4 used the same preparation method and flame composite gas device as Example 1. The only difference was that the molecular sieve adsorbent filled in the gas purification device was different and the specific process parameters of flame composite were different, as shown in Table 1. The performance of the obtained low-odor, low-VOC composite skin was tested, and the results are shown in Table 2.

[0061] In this embodiment, the impurity content of the gas at the gas station outlet, the air at the air source outlet, and the mixed gas at the gas purification device outlet were sampled and tested. The results are as follows:

[0062] The liquefied petroleum gas at the gas station outlet contains: benzene 100 ppm, toluene 48 ppm, ethylbenzene 57 ppm, naphthalene 132 ppm, hydrogen sulfide sulfur 14 ppm, mercaptan sulfur 315 ppm, and carbonyl sulfur 16 ppm.

[0063] At the air source outlet, the following concentrations of substances were present in the air: benzene 42 ppm, toluene 28 ppm, ethylbenzene 32 ppm, formaldehyde 21 ppm, acetaldehyde 14 ppm, and acrolein 5 ppm.

[0064] The mixed gas at the outlet of the gas purification device contained the following: benzene 6 ppm, toluene 3 ppm, ethylbenzene not detected, naphthalene 3 ppm, hydrogen sulfide not detected, mercaptan sulfide 5 ppm, carbonyl sulfide 2 ppm, formaldehyde 1.6 ppm, acetaldehyde 1.1 ppm, and acrolein not detected.

[0065] Table 1. Parameters of Molecular Sieve Adsorbents and Flame Composite Process in the Gas Purification Devices of Examples 1-4

[0066]

[0067]

[0068]

Comparative Example 1

[0069] A method for preparing a composite epidermis includes the following steps:

[0070] 1) Turn on the LPG and blower switches, adjust the LPG and air flow ratio to 70:30, and set the LPG pipeline pressure to 6.0 kPa;

[0071] 2) Start the flame composite machine, set the upper gap to 2.5mm, the lower gap to 2.0mm, the upper flame port distance to 50mm, the lower flame port distance to 60mm, the upper flame port mixing airflow index to 75%, the lower flame port mixing airflow index to 60%, and the main unit speed to 20m / min.

[0072] 3) After the liquefied gas and air are mixed by the mixer, they enter the flame laminating machine. The flame laminating machine is ignited, and the flame melts one side of the sponge at the upper flame port to form an adhesive film. The sponge and the base fabric are bonded together to form a composite semi-finished product.

[0073] 4) Burn and melt the sponge on the other side of the composite semi-finished product at the lower burner to form an adhesive film. The composite semi-finished product and PVC leather are bonded together through the adhesive film to obtain the composite skin.

[0074] 5) During the compounding process, the flame temperature of the upper and lower burners is manually measured. The flame temperature of the upper burner is 820℃ and the flame temperature of the lower burner is 831℃. The pressure gauge monitors the pressure of the gas pipeline. When the pressure exceeds the set range, the machine is stopped for inspection.

[0075] 6) The performance of the prepared composite skin was tested, and the results are shown in Table 2.

[0076] This embodiment uses a conventional gas device, including a liquefied petroleum gas (LPG) chamber, a blower, a mixer, a flame combining machine, and an exhaust gas treatment device. The LPG chamber is connected to the inlet of the mixer via a gas pipeline, which is equipped with a first pressure gauge and a first solenoid valve. The blower is connected to the inlet of the mixer via an air pipeline, which is equipped with a second pressure gauge and a second solenoid valve. The outlet of the mixer is connected to the flame combining machine via a mixed gas pipeline equipped with a third pressure gauge and a third solenoid valve. A gas vent pipe is installed on the mixed gas pipeline before the flame combining machine, and a manual ball valve is installed on the gas vent pipe. The end of the gas vent pipe is connected to the exhaust gas treatment device. The flame combining machine and the exhaust gas treatment device are connected together.

[0077] In this embodiment, the impurity content of liquefied gas and air at the fan outlet was sampled and tested. The results are as follows:

[0078] In liquefied petroleum gas (LPG): benzene content is 115 ppm, toluene content is 56 ppm, ethylbenzene content is 54 ppm, naphthalene content is 129 ppm, hydrogen sulfide sulfur content is 21 ppm, mercaptan sulfur content is 299 ppm, and carbonyl sulfur content is 25 ppm.

[0079] In the air: benzene content is 58 ppm, toluene content is 18 ppm, ethylbenzene content is 22 ppm, formaldehyde content is 16 ppm, acetaldehyde content is 18 ppm, and acrolein content is 8 ppm.

[0080] [Comparative Example 2]

[0081] Comparative Example 2 used the same preparation method and gas device as Comparative Example 1, the only difference being the specific process parameters of flame composite, which were: upper spacing 2.7 mm, lower spacing 2.2 mm, upper burner distance 50 mm, lower burner distance 60 mm, upper burner mixed airflow index 80%, lower burner mixed airflow index 65%, main engine speed 25 m / min, upper burner flame temperature 868℃, and lower burner flame temperature 875℃. The performance of the obtained composite skin was tested, and the results are shown in Table 2.

[0082] In this embodiment, the impurity content of the liquefied gas and the air at the fan outlet was sampled and tested. The data are as follows:

[0083] In liquefied petroleum gas (LPG): benzene content is 119 ppm, toluene content is 61 ppm, ethylbenzene content is 56 ppm, naphthalene content is 121 ppm, hydrogen sulfide sulfur content is 25 ppm, mercaptan sulfur content is 302 ppm, and carbonyl sulfur content is 19 ppm.

[0084] In the air: benzene content is 60 ppm, toluene content is 19 ppm, ethylbenzene content is 25 ppm, formaldehyde content is 18 ppm, acetaldehyde content is 20 ppm, and acrolein content is 6 ppm.

[0085] Table 2 Performance test data of composite epidermis in Examples 1-4 and Comparative Examples 1-2

[0086]

[0087] Table 2 shows that the odor rating of the composite skins prepared in Examples 1-4 is 3.0-3.5, which is lower than that of Comparative Examples 1-2, indicating a low odor. In the VOC test results for 1 cubic meter, TVOC < 200 μg / m³. 3 Benzene is ND, toluene <10μg / m 3 Ethylbenzene < 5 μg / m 3 Xylene <15 μg / m 3 Styrene is ND, formaldehyde <6μg / m³ 3 Acetaldehyde < 30 μg / m 3 Acrylaldehyde is an N-type compound, and the composite product has the advantage of low VOC content.

[0088] In summary, the composite skin produced by this invention, due to the addition of a gas purification device filled with molecular sieve adsorbent in the gas combustion device, can fully adsorb and purify the gas and air, removing residual small volatile substances such as aromatics, sulfides, ammonia, and cyanides from the gas. This ensures that the gas entering the flame composite machine is sufficiently pure. As shown in the impurity detection data of the sampled gas in Examples 1-4, the impurities in the gas and air are fully purified, and the impurity content in the mixed gas exiting the gas purification device is significantly reduced. This reduces the quality problems caused by impurities in the raw material gas to the composite product, effectively reduces the odor level and VOC content of the composite product, and achieves good technical results. It can be used in the industrial production of automotive interior composite skins.

Claims

1. A method for preparing a low-odor, low-VOC composite skin, comprising the following steps: In a flame-combining gas device, the gas and air are dried and then enter a gas buffer tank and an air buffer tank, respectively. The gas from the gas buffer tank enters the mixer after being controlled by gas pressure. Air from the air buffer tank enters the mixer after being controlled by air pressure. By controlling the flow rates of gas and air, the volume ratio of gas and air in the mixer is adjusted to obtain a uniform gas mixture. The mixed gas enters a gas purification device filled with molecular sieve adsorbents, where aromatics, sulfides, ammonia, cyanides, formaldehyde, acetaldehyde, and acrolein are adsorbed and removed from the mixed gas, resulting in a purified mixed gas. The purified mixed gas enters the flame laminating machine, where the sponge is ignited at the burner to perform flame lamination, resulting in a low-odor, low-VOC composite skin. The molecular sieve adsorbent is selected from lanthanum-loaded ZSM-5 / mordenite symbiotic molecular sieve, copper-loaded MCM-22 molecular sieve, copper and zinc-loaded MCM-49 molecular sieve, or a mixture of copper-loaded MCM-22 molecular sieve and copper and zinc-loaded MCM-49 molecular sieve. The lanthanum-loaded ZSM-5 / mordenite symbiotic molecular sieve has a lanthanum content of 0.5% by mass and a SiO2 / Al2O3 molar ratio of 15~30. The copper-loaded MCM-22 molecular sieve has a copper mass percentage of 0.6% and a SiO2 / Al2O3 molar ratio of 80~110. The copper- and zinc-loaded MCM-49 molecular sieve has a copper mass percentage of 0.3%, a zinc mass percentage of 0.4%, and a SiO2 / Al2O3 molar ratio of 15-25. In the mixture of copper-loaded MCM-22 molecular sieve and copper- and zinc-loaded MCM-49 molecular sieve, the mass ratio of copper-loaded MCM-22 molecular sieve to copper- and zinc-loaded MCM-49 molecular sieve is 1:3.5; wherein the copper-loaded MCM-22 molecular sieve has a copper mass percentage of 0.4% and a SiO2 / Al2O3 molar ratio of 105; and the copper- and zinc-loaded MCM-49 molecular sieve has a copper mass percentage of 0.3%, a zinc mass percentage of 0.4%, and a SiO2 / Al2O3 molar ratio of 22. The pressure of both the gas and air is controlled at 4.0~8.0 kPa, and the volume ratio of gas to air in the mixer is 60~80:

30.

2. The method for preparing a low-odor, low-VOC composite skin according to claim 1, characterized in that, The flame-blending gas device includes a gas chamber (1), an air source (2), an air dryer (3), a gas dryer (3'), a gas buffer tank (4), an air buffer tank (5), a mixer (6), a gas purification device (7), and a flame-blending machine (8); wherein, the outlet of the gas chamber (1) is connected to the inlet of the gas buffer tank (4) through the gas dryer (3'); the outlet of the air source (2) is connected to the inlet of the air buffer tank (5) through the air dryer (3); the gas buffer... The outlet of the tank (4) is connected to the inlet of the mixer (6) through a gas pipeline equipped with a gas pressure control device; the outlet of the air buffer tank (5) is connected to the inlet of the mixer (6) through an air pipeline equipped with an air pressure control device; the outlet of the mixer (6) is connected to the bottom inlet of the gas purification device (7) containing molecular sieve adsorbents; the top outlet of the gas purification device (7) is connected to the flame composite machine (8) through a mixed gas pipeline equipped with a mixed gas pressure control device.

3. The method for preparing a low-odor, low-VOC composite skin according to claim 2, characterized in that, A gas flow controller (4-3) is provided on the pipeline between the gas buffer tank (4) and the mixer (6); an air flow controller (5-3) is provided on the pipeline between the air buffer tank (5) and the mixer (6).

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