Production method of home decoration environment-friendly composite layer based on air film structure

Abstract

The present application relates to the technical field of composite layer production, and particularly relates to a home decoration environment-friendly composite layer production method based on a gas film structure, which comprises the following steps: pretreating a mixture of biodegradable high-molecular resin, plant fiber filler, heat stabilizer and nucleating agent with a preset proportion to obtain a mixed material; melt plasticizing the mixed material to obtain a polymer melt, and determining whether the uniformity of the mixed material is qualified to adjust the preset screw rotation speed; determining and responding to a gas injection mode of the polymer melt to form a gas-containing polymer melt; calendering and stretching the gas-containing polymer melt to form a home decoration environment-friendly composite layer blank, and determining whether the gas film development is qualified based on the acoustic attenuation coefficient; in response to unqualified gas film development, determining unqualified factors of the gas film development and adjusting the calendering and stretching parameters; and in response to qualified gas film development, determining to cool and shape the home decoration environment-friendly composite layer blank to fix the gas film structure, and obtaining the home decoration environment-friendly composite layer. The present application solves the uncontrollable problem in the foaming process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite layer production, and in particular to a home decoration environment-friendly composite layer production method based on a gas film structure. BACKGROUND

[0002] With the increasing of social environmental awareness and the deepening of the concept of sustainable development, the field of home decoration materials is rapidly developing towards green, low-carbon and recyclable. The material composed of biodegradable polymers and plant fibers has become an important choice to replace traditional petroleum-based boards. In order to reduce the density and improve the performance of heat and sound insulation, it is often necessary to introduce a porous structure into the material.

[0003] At present, the chemical foaming agent method is mainly used in the industry to realize foaming. This method blends the foaming agent with the raw material, and relies on the decomposition of the foaming agent to produce gas and form pores during heating. However, this method has significant shortcomings: first, the foaming process is greatly affected by factors such as heating history, and the nucleation and growth of bubbles are difficult to control, resulting in poor uniformity of the pore structure; second, bubbles are prone to merge during growth, forming irregular large pores or through holes, which damage the mechanical and functional properties of the material; third, the residue of some foaming agents may affect the degradability of the material or introduce volatile substances, which is contrary to the goal of environmental protection.

[0004] Chinese patent publication No. CN111572145A discloses a foamed plastic-wood composite material board and a preparation method thereof, which belongs to the technical field of composite materials and new chemical building materials. The invention is composed of a foamed plastic-wood core layer, a foamed plastic-wood intermediate layer, and a foamed plastic-wood outer shell layer. The foamed plastic-wood intermediate layer is located between the foamed plastic-wood core layer and the foamed plastic-wood outer shell layer. The invention is convenient to produce, has strong production continuity, high production efficiency, small density, light weight, waterproof, corrosion-resistant, insect-resistant, non-cracking, non-aging, no color difference, no paint falling during use, good touch, not easy to deform, good heat resistance, recyclable, environmentally friendly, low cost, etc.

[0005] Therefore, the foamed plastic-wood composite material board and the preparation method thereof have the following problems:

[0006] 1. The foaming process still relies on chemical foaming agents, and the foaming process is uncontrollable, which makes it difficult to predict the nucleation and growth of bubbles, and it is impossible to achieve uniformity of cell size and distribution, and bubble coalescence and collapse are prone to occur, affecting the stability of the material structure and functional performance;

[0007] 2. There is a lack of real-time monitoring and feedback control mechanism in the production process, so it is difficult to ensure the consistency of the product gas film structure, and the quality fluctuates greatly between batches. SUMMARY

[0008] To this end, the present application provides a kind of based on gas film structure's home decoration environmental protection composite layer production method to overcome the technical problems of uncontrollable foaming process of chemical foaming agent and uneven gas film structure in prior art.

[0009] To achieve the above object, the present application provides a kind of based on gas film structure's home decoration environmental protection composite layer production method, comprising:

[0010] The preset proportion of biodegradable high molecular resin, plant fiber filler, heat stabilizer and nucleating agent is placed in a high-speed mixer for pretreatment to obtain a mixture;

[0011] The mixture is placed in a twin-screw extruder for melt plasticizing treatment at a preset screw rotation speed and a preset gradient temperature to obtain a polymer melt, and the standard deviation of the characteristic absorption peak intensity of the mixture is calculated by acquiring the characteristic absorption peak intensity data sequence during the melt plasticizing treatment of the mixture;

[0012] The uniformity of the mixture is determined based on the standard deviation of the characteristic absorption peak intensity to adjust the preset screw rotation speed;

[0013] In response to the uniformity of the mixture being qualified, the polymer melt is placed in a calender containing at least one inert gas injection device, and the fiber volume fraction and resin characteristic viscosity of the polymer melt are calculated to determine the rheological coefficient to determine the gas injection mode, and the polymer melt is injected with gas to form a gas-containing polymer melt in response to the gas injection mode;

[0014] The gas-containing polymer melt is calendered and stretched at a preset stretching rate and a preset roll gap to form a home decoration environmental protection composite layer initial blank with a gas film structure, and the acoustic wave attenuation coefficient of several preset points of the home decoration environmental protection composite layer initial blank is acquired to determine whether the gas film development of the home decoration environmental protection composite layer initial blank is qualified;

[0015] In response to the gas film development of the home decoration environmental protection composite layer initial blank being qualified, it is determined that the home decoration environmental protection composite layer initial blank is introduced into a cooling setting machine for preset temperature cooling treatment to fix the gas film structure, and a home decoration environmental protection composite layer is obtained;

[0016] The preset proportion is 60-80 parts by weight of biodegradable high molecular resin, 20-40 parts of plant fiber filler, 1-5 parts of heat stabilizer and 0.5-3 parts of nucleating agent.

[0017] Further, the process of calculating the standard deviation of the characteristic absorption peak intensity of the mixture includes:

[0018] The near-infrared spectrum of the mixture during melt plasticizing treatment is continuously collected on the melt flow channel at the extruder die at a preset frequency;

[0019] reading several absorbance values at characteristic wavelengths within a wavelength band of 1450 nm to 2100 nm;

[0020] the absorbance values are intensities of the characteristic absorption peaks;

[0021] calculating a standard deviation of the intensities of the characteristic absorption peaks acquired over a preset time duration.

[0022] Further, the process of determining whether the uniformity of the mixture is qualified to adjust the preset screw rotation speed comprises:

[0023] comparing the standard deviation of the intensities of the characteristic absorption peaks with a preset standard deviation;

[0024] based on the standard deviation of the intensities of the characteristic absorption peaks being less than or equal to the preset standard deviation, determining that the uniformity of the mixture is qualified, and obtaining a polymer melt;

[0025] based on the standard deviation of the intensities of the characteristic absorption peaks being greater than the preset standard deviation, determining that the uniformity of the mixture is not qualified;

[0026] in response to the uniformity of the mixture being not qualified, calculating a relative deviation value of the standard deviation of the intensities of the characteristic absorption peaks from the preset standard deviation to determine a rotation speed adjustment amount to increase the preset screw rotation speed, wherein,

[0027] the relative deviation value is positively correlated with the rotation speed adjustment amount.

[0028] Further, the process of determining the gas injection mode comprises:

[0029] determining a rheological coefficient based on a product of the fiber volume fraction and the resin intrinsic viscosity;

[0030] comparing the rheological coefficient with a preset rheological coefficient;

[0031] based on the rheological coefficient being less than the preset rheological coefficient, determining that the gas injection mode is a first gas injection mode;

[0032] based on the rheological coefficient being greater than or equal to the preset rheological coefficient, determining that the gas injection mode is a second gas injection mode, wherein,

[0033] the first gas injection mode is a continuous injection of inert gas into the polymer melt at a pressure of 1.5 Bar and a flow rate of 0.25 L / min, and the second gas injection mode is a pulsed injection of inert gas into the polymer melt at a pressure of 2 Bar, an injection time duration of 0.5 seconds, a single pulse injection gas volume of 0.2 mL, and an intermittent time duration of 2.0 seconds, in response to the first gas injection mode or the second gas injection mode to form a gas-containing polymer melt.

[0034] Further, the biodegradable polymer resin includes one or more of polylactic acid, polyhydroxyalkanoate, polybutylene succinate, polybutylene terephthalate, and a blend of one or more of polybutylene succinate and polybutylene terephthalate.

[0035] Further, the process of determining the formation of the home decoration environment-friendly composite layer preliminary product with the air film structure includes:

[0036] Directing the gas-containing polymer melt between a pair of counter-rotating heated rollers;

[0037] Calendering and longitudinally stretching the home decoration environment-friendly composite layer preliminary product containing flat strip-shaped pores or stacked air bags at a preset stretching rate through a preset nip of the heated rollers.

[0038] Further, the process of determining whether the air film development of the home decoration environment-friendly composite layer preliminary product is qualified includes:

[0039] Emitting ultrasonic pulses to a plurality of preset points of the home decoration environment-friendly composite layer preliminary product to obtain ultrasonic signal amplitude values of the plurality of preset points of the home decoration environment-friendly composite layer preliminary product;

[0040] Calculating a plurality of sound wave attenuation coefficients based on the plurality of ultrasonic signal amplitude values, and calculating a standard deviation of the sound wave attenuation coefficients;

[0041] Comparing the standard deviation of the sound wave attenuation coefficients with a preset standard deviation of the sound wave attenuation coefficients;

[0042] Based on the standard deviation of the sound wave attenuation coefficients being greater than or equal to the preset standard deviation of the sound wave attenuation coefficients, determining that the air film development of the home decoration environment-friendly composite layer preliminary product is unqualified;

[0043] Based on the standard deviation of the sound wave attenuation coefficients being less than the preset standard deviation of the sound wave attenuation coefficients, determining that the air film development of the home decoration environment-friendly composite layer preliminary product is qualified.

[0044] Further, the plant fiber filler is a natural plant fiber that has been dried and pulverized, including one or more of a mixture of wood powder, bamboo powder, rice husk powder, straw powder, and coconut shell powder, and the particle size of the plant fiber filler is 80 to 300 mesh.

[0045] Further, in response to the unqualified air film development of the home decoration environment-friendly composite layer preliminary product, the process of adjusting the calendering and stretching parameters includes:

[0046] Determining a nip adjustment amount based on the pore size to increase the preset nip;

[0047] Determining a stretching rate adjustment amount based on the pore distribution to decrease the preset stretching rate, wherein,

[0048] The roll gap adjustment amount is determined based on a relative deviation rate of the barycentric frequency offset, and the stretching rate adjustment amount is determined based on a relative deviation rate of the standard deviation of the acoustic wave attenuation coefficient.

[0049] Further, the process for obtaining the environmentally-friendly composite layer for home decoration comprises:

[0050] The environmentally-friendly composite layer for home decoration is guided to a set of cooling rollers with preset temperatures decreasing in sequence;

[0051] The environmentally-friendly composite layer for home decoration is made to travel along the transmission path of the cooling rollers at a preset cooling rate, and the temperature of the environmentally-friendly composite layer for home decoration is reduced to below the glass transition temperature of the polymer substrate through heat dissipation by conduction, so as to solidify and lock the internal air film structure, and obtain the environmentally-friendly composite layer for home decoration.

[0052] Compared with the prior art, the present application has the beneficial effects that the present application uses green and environmentally-friendly raw materials of biodegradable high molecular resin and plant fiber filler, determines whether the uniformity of the mixed material is qualified by calculating the standard deviation of the characteristic absorption peak intensity, thereby adjusting the preset screw rotation speed, improves the uniformity of the mixed material, and calculates the rheological coefficient based on the fiber volume fraction and the resin characteristic viscosity and determines the gas injection mode, changes the random foaming depending on experience to the customized structured gas injection according to the material properties. This makes the gas-containing polymer melt after calendering and stretching be able to accurately form a preset gradient channel (optimizing sound insulation) or an isolated air bag (optimizing heat preservation), solves the technical problems of uncontrollable structure and difficult performance improvement of chemical foaming materials, judges whether the air film development is qualified by the standard deviation of the acoustic wave attenuation coefficient, realizes nondestructive testing of the air film structure, and determines the unqualified factors of the air film development to optimize the preset stretching rate or the preset roll gap, thereby improving the qualification rate of the product.

[0053] Further, the present application monitors the characteristic absorption peak intensity of the plant fiber in the mixed material within a specific wave band, which can not only accurately capture the microscopic dispersion defects such as plant fiber agglomeration, local enrichment or absence, but also correlate the real-time influence of the preset screw rotation speed and the preset gradient temperature on the dispersion effect, thereby improving the accuracy and timeliness of the melt homogeneity judgment, avoiding batch quality fluctuations or continuous production waste caused by parameter solidification or adjustment lag, preventing subsequent air film structure instability, product mechanical property decline and other problems caused by uneven mixing of raw materials. It ensures the stability of the process chain from raw materials to intermediate products, reduces the cost and energy consumption caused by rework or waste, and enhances the consistency and reliability of the performance of the final environmentally-friendly composite layer for home decoration product.

[0054] Further, the application determines the quantitative correlation of material properties through the rheological coefficient, which can capture the changes in melt strength and viscosity caused by formulation fluctuations, and correlate the impact of such changes on the forming behavior of gas in the melt, thereby improving the predictability and success rate of the gas film structure forming. The first gas injection mode (continuous and stable) or the second gas injection mode (intermittent and pulsed) avoids defects such as excessive merging of gas pores, structure collapse or insufficient foaming caused by mismatch between process and material, prevents problems such as unstable and fluctuating sound insulation and thermal insulation performance of the product caused by this, ensures that the gas pore structure can be accurately constructed according to the preset target, reduces the rate of substandard products, enhances the adaptability of the production process to different formulation systems and the uniformity of product performance, and ensures the high reliability of the final composite layer function.

[0055] Further, the application evaluates and determines the development state of the gas film through acoustic wave detection, achieving accurate diagnosis of the uniformity of the internal structure, which can capture microscopic structural defects such as local gas pore merging and missing caused by uneven inert gas injection or mismatched calendering parameters, and correlate the impact of the preset stretching rate and preset roll gap settings on the morphology and distribution of the gas film, improving the accuracy of the prediction of the sound insulation and thermal insulation performance of the product, avoiding continuous production of unqualified products and batch waste of raw materials caused by late quality inspection, identifying gas film structure abnormalities in advance, providing reliable decision-making basis for subsequent process adjustment, ensuring the reliability and stability of the performance of the home environmental protection composite layer product between batches, reducing the risk of market returns, and enhancing stable production of the production line.

[0056] Further, the application diagnoses unqualified gas film development of the home environmental protection composite layer initial blank through the acoustic index of the center of gravity frequency offset, achieving tracing and classification of unqualified factors of gas film development. This can capture the macro trend of overall large gas pore size caused by insufficient calendering, and correlate the uniformity problem of gas pore size distribution caused by stretching rate, improving the accuracy of production problem attribution, avoiding the blindness and trial-and-error cost of subsequent production method adjustment, preventing further deterioration of the structure of the home environmental protection layer initial blank or the generation of new defects caused by misuse of a single adjustment strategy, ensuring the effectiveness of process optimization and the ability to produce qualified products, reducing the production of unqualified products, and enhancing the self-healing ability of the production method when facing fluctuations.

[0057] Further, the present application realizes the stable solidification and permanent locking of the gas film structure by controlling the cooling and shaping process with preset temperature and preset cooling rate. This can capture and adapt to the differences in inherent glass transition temperature and crystallization characteristics of different polymer melts, correlate and eliminate the structural rebound tendency caused by the residual thermal stress of the primary blank after calendering and stretching, improve the structural fidelity from metastable state to final product, avoid the risk of structural instability caused by uneven cooling, such as product warping, deformation and internal stress concentration, prevent problems such as pore wall rupture, structure collapse or insufficient crystallinity caused by too fast or too slow cooling, and ensure that the lightweight high-strength, soundproof and heat-insulating functional gas film structure is completely and stably retained in the final product. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 The step flow chart of the production method of the home decoration environment-friendly composite layer based on the gas film structure of the embodiment of the present application is shown in the figure.

[0059] Figure 2 The step flow chart of determining whether the mixture is qualified is shown in the figure.

[0060] Figure 3 The step flow chart of determining the gas injection mode of the polymer melt is shown in the figure.

[0061] Figure 4 The step flow chart of determining whether the gas film development of the home decoration environment-friendly composite layer primary blank is qualified is shown in the figure. DETAILED DESCRIPTION

[0062] In order to make the purpose and advantages of the present application clearer and more apparent, the present application will be further described below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0063] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0064] It should be noted that in the description of the present application, the terms "upper", "lower", "left", "right", "inner", "outer" and the like indicate the direction or positional relationship terms based on the direction or positional relationship shown in the drawings, which are only for the convenience of description and do not indicate or imply that the device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0065] Please refer to Figure 1 The step flow chart of the production method of the home decoration environment-friendly composite layer based on the gas film structure of the embodiment of the present application is shown in the figure.

[0066] The embodiment of the present application is based on a production method of a home decoration environment-friendly composite layer based on a gas film structure, comprising:

[0067] The biodegradable high molecular resin, the plant fiber filler, the thermal stabilizer and the nucleating agent with a preset proportion are put into a high-speed mixer for pretreatment to obtain a mixture;

[0068] The mixture is put into a double screw extruder for melt plasticizing treatment of the mixture at a preset screw rotation speed and a preset gradient temperature to obtain a polymer melt, and a characteristic absorption peak intensity data sequence in the melt plasticizing treatment process of the mixture is obtained to calculate the standard deviation of the characteristic absorption peak intensity of the mixture;

[0069] Based on the standard deviation of the characteristic absorption peak intensity, whether the uniformity of the mixture is qualified is determined to adjust the preset screw rotation speed;

[0070] In response to the uniformity of the mixture being qualified, the polymer melt is put into a calender containing at least one inert gas injection device, and the fiber volume fraction and the resin intrinsic viscosity of the polymer melt are calculated to determine the rheological coefficient to determine the gas injection mode, and the polymer melt is injected into the gas to form a gas-containing polymer melt in response to the gas injection mode;

[0071] The gas-containing polymer melt is calendered and stretched at a preset stretching rate and a preset roll gap to form a home decoration environment-friendly composite layer preliminary blank with a gas film structure, and the acoustic wave attenuation coefficient of a plurality of preset point positions of the home decoration environment-friendly composite layer preliminary blank is obtained to determine whether the gas film development of the home decoration environment-friendly composite layer preliminary blank is qualified;

[0072] In response to the gas film development of the home decoration environment-friendly composite layer preliminary blank being qualified, it is determined that the home decoration environment-friendly composite layer preliminary blank is introduced into a cooling setting machine for preset temperature cooling treatment to fix the gas film structure to obtain the home decoration environment-friendly composite layer;

[0073] The preset proportion is that the biodegradable high molecular resin is 60-80 parts by weight, the plant fiber filler is 20-40 parts by weight, the thermal stabilizer is 1-5 parts by weight, and the nucleating agent is 0.5-3 parts by weight.

[0074] Specifically, the present application uses biodegradable polymer resin and plant fiber filler as green and environmentally friendly raw materials, determines whether the uniformity of the mixture is qualified by calculating the standard deviation of the characteristic absorption peak intensity, adjusts the preset screw speed, improves the uniformity of the mixture, and calculates the rheological coefficient based on the fiber volume fraction and the resin intrinsic viscosity to determine the gas injection mode, changing the random foaming which depends on experience into the structured gas injection according to the material properties. This makes the gas-containing polymer melt accurately form the preset gradient channel (optimizing sound insulation) or isolation air bag (optimizing heat preservation) after calendering and stretching, solves the technical problems of uncontrollable structure and difficult performance improvement of chemical foaming materials, judges whether the gas film development is qualified by the standard deviation of the sound wave attenuation coefficient, realizes nondestructive testing of the gas film structure, and determines the unqualified factors of the gas film development to optimize the preset stretching rate or preset roll gap, thereby improving the qualified rate of the product.

[0075] Specifically, the biodegradable polymer resin, plant fiber filler, thermal stabilizer and nucleating agent of the preset ratio are weighed by mass fraction and placed in a high-speed mixer for pretreatment to obtain a mixture.

[0076] In the embodiment of the present application, the preset ratio is that the biodegradable polymer resin is 60-80 parts by weight, the plant fiber filler is 20-40 parts by weight, the thermal stabilizer is 1-5 parts by weight, and the nucleating agent is 0.5-3 parts by weight.

[0077] In the embodiment of the present application, the biodegradable polymer resin includes a blend of one or more of polylactic acid, polyhydroxyalkanoate, polybutylene succinate, polyhexanedioic acid and polybutylene terephthalate.

[0078] In the embodiment of the present application, the plant fiber filler is a natural plant fiber treated by drying and crushing, including a mixture of one or more of wood powder, bamboo powder, rice husk powder, straw powder and coconut shell powder, and the particle size of the plant fiber filler is 80-300 mesh.

[0079] In the embodiment of the present application, the process of placing the mixture in the high-speed mixer for pretreatment includes: according to the preset ratio, the biodegradable polymer resin, plant fiber filler, thermal stabilizer and nucleating agent are sequentially added to the mixing cavity of the high-speed mixer, the dry powder is preliminarily dispersed uniformly at 500 rpm for 2 minutes, the rotation speed is increased to 1300 rpm, the temperature of the mixture is increased to 90℃ for 3 minutes, and the mixture is obtained after cooling.

[0080] Specifically, the process of placing the mixture in the double-screw extruder for melt plasticizing treatment of the mixture at the preset screw speed and preset gradient temperature to obtain a polymer melt and obtaining a characteristic absorption peak intensity data sequence of the mixture to calculate the standard deviation of the characteristic absorption peak intensity of the mixture includes:

[0081] continuously collecting near-infrared spectrum of the mixture during the melting plasticizing process at a preset frequency on the melt flow channel at the extruder die;

[0082] reading several absorbance values at characteristic wavelengths within the wavelength band of 1450nm to 2100nm;

[0083] the absorbance value is the characteristic absorption peak intensity;

[0084] calculating the standard deviation of the characteristic absorption peak intensity collected for a preset time length.

[0085] In the embodiment of the present application, the absorbance value at the preset characteristic wavelength within the wavelength band of 1450nm to 2100nm is read, and the absorbance value is continuously collected at a preset frequency to form a characteristic absorption peak intensity data sequence.

[0086] In the embodiment of the present application, the preset screw rotation speed is within the range of [100rpm, 400rpm], and is preferably set to 250rpm, and the preset gradient temperature is within the range of [150℃, 200℃], and is preferably distributed in an increasing manner from the feeding port to the die along the extrusion direction, and the temperature gradient is preferably set to [160℃, 175℃, 190℃], but the above values are not limited thereto, and the values can be adjusted according to actual needs by those skilled in the art.

[0087] In the embodiment of the present application, a transmission probe of an online near-infrared spectrometer is installed on the melt flow channel between the die of the twin-screw extruder and the mouth die, the preset frequency is within the range of [1Hz, 10Hz], and is preferably set to 5Hz, and the preset time length is within the range of [10s, 60s], and is preferably set to 30s, but the above values are not limited thereto, and the values can be adjusted according to actual needs by those skilled in the art.

[0088] In the embodiment of the present application, the plant fiber filler has a great influence on the strength and viscosity of the polymer melt as a reinforcing phase, and is poor in compatibility with the resin matrix as a dispersed phase, and is most likely to be unevenly distributed, agglomerated or locally missing during the processing process, and the monitoring wavelength band of 1450nm to 2100nm is a strong characteristic absorption region of the combination frequency (about 1930-2100nm) of the stretching vibration (about 1450nm) and the bending vibration of the hydroxyl group contained in cellulose / hemicellulose in the plant fiber, and can reflect the uniformity of the mixture.

[0089] Please refer to Figure 2 which is a step flow chart for determining whether the uniformity of the mixture is qualified or not according to the embodiment of the present application.

[0090] Specifically, the process of determining whether the uniformity of the mixed material is qualified based on the standard deviation of the characteristic absorption peak intensity of the mixed material to adjust the preset screw rotation speed comprises:

[0091] If the standard deviation of the characteristic absorption peak intensity is greater than the preset standard deviation, it is determined that the mixed material is unqualified;

[0092] If the standard deviation of the characteristic absorption peak intensity is less than or equal to the preset standard deviation, it is determined that the uniformity of the mixed material is qualified, and the polymer melt is obtained.

[0093] In response to the unqualified uniformity of the mixed material, the relative deviation value of the standard deviation of the characteristic absorption peak intensity and the preset standard deviation is calculated to determine the rotation speed adjustment amount to increase the preset screw rotation speed, wherein,

[0094] The relative deviation value is positively correlated with the rotation speed adjustment amount.

[0095] In the embodiment of the application, the relative deviation value=(standard deviation of the characteristic absorption peak intensity-preset standard deviation) / preset standard deviation, and the rotation speed adjustment amount=k x relative deviation value x preset screw rotation speed. The value range of the proportionality coefficient k determined based on the production debugging stage is [0.2, 0.3], and the proportionality coefficient k is preferably set to 0.25. However, the above value is not limited thereto, and a person skilled in the art can also adjust the value according to actual needs.

[0096] In the embodiment of the application, the value range of the preset standard deviation determined based on the standard deviation of the characteristic absorption peak intensity of the historically qualified polymer melt is [0.02, 0.20], and the preset standard deviation is preferably set to 0.12. However, the above value is not limited thereto, and a person skilled in the art can also adjust the value according to actual needs.

[0097] Specifically, the application can accurately capture the microscopic dispersion defects such as plant fiber agglomeration, local enrichment or absence by monitoring the characteristic absorption peak intensity of plant fibers in a specific waveband, and can also correlate the real-time influence of the preset screw rotation speed and the preset gradient temperature on the dispersion effect, thereby improving the accuracy and timeliness of the melt homogeneity determination, avoiding batch quality fluctuations or continuous production waste caused by parameter solidification or adjustment lag, and preventing subsequent problems such as unstable gas film structure and decreased product mechanical properties caused by uneven mixing of raw materials. The process chain stability from raw materials to intermediate products is ensured, the cost and energy consumption caused by rework or waste products are reduced, and the consistency and reliability of the performance of the final home environmental protection composite layer product are enhanced.

[0098] Please refer to Figure 3 , which is a step flow chart of determining the gas injection mode of the polymer melt according to the embodiment of the application.

[0099] Specifically, the process of placing the polymer melt in a calendering machine with at least one inert gas injection device, obtaining the fiber volume fraction of the polymer melt and the resin intrinsic viscosity to calculate the rheological coefficient to determine the gas injection mode includes:

[0100] determining the rheological coefficient based on the product of the fiber volume fraction and the resin intrinsic viscosity;

[0101] comparing the rheological coefficient with a preset rheological coefficient;

[0102] if the rheological coefficient is less than the preset rheological coefficient, determining that the gas injection mode is a first gas injection mode;

[0103] if the rheological coefficient is greater than or equal to the preset rheological coefficient, determining that the gas injection mode is a second gas injection mode;

[0104] wherein the first gas injection mode is to continuously inject inert gas into the polymer melt at a pressure of 1.5 Bar and a flow rate of 0.25 L / min, and the second gas injection mode is to pulse inject inert gas into the polymer melt at a pressure of 2 Bar, an injection time of 0.5 seconds, a single pulse injection gas volume of 0.2 mL, and an intermittent time of 2.0 seconds.

[0105] In the embodiment of the present application, the fiber volume fraction affects the strength and rigidity of the melt, and the intrinsic viscosity of the resin dominates the bulk viscosity of the melt. Both of them together determine the ability of the melt to wrap the injected gas and resist its merging, breaking or escaping during the calendering and stretching process. Therefore, the rheological coefficient is determined based on the product of the fiber volume fraction and the resin intrinsic viscosity.

[0106] In the embodiment of the present application, the preset rheological coefficient is determined based on historical processes, and the value range is [0.35, 0.60], preferably set to 0.45, but the above value is not limited thereto, and the skilled person in the art can also adjust the value according to actual needs.

[0107] In the embodiment of the present application, the fiber volume fraction = (mass of plant fiber / density of plant fiber) / [(mass of plant fiber / density of plant fiber + mass of resin / density of resin)], the resin intrinsic viscosity is obtained by the known intrinsic parameters of the selected specific grade of biodegradable polymer resin, and the inert gas is nitrogen with a gas purity of greater than 99.5%.

[0108] Specifically, the process of injecting the polymer melt with gas to form a gas-containing polymer melt in response to the gas injection mode includes,

[0109] If the gas injection mode is the first injection mode, it is determined that the inert gas is continuously injected into the polymer melt flowing before the calendering nip at a constant pressure of 1.5 Bar and a constant volume flow of 0.25 L / min;

[0110] If the gas injection mode is the second injection mode, it is determined that the inert gas is injected into the polymer melt flowing before the calendering nip in a periodic pulse mode with a pressure of 2.0 Bar, an opening time of 0.5 seconds and a closing time of 2.0 seconds;

[0111] The inert gas is wrapped by the polymer melt to form a gas-containing polymer melt containing a dispersed gas cavity inside.

[0112] In the embodiment of the present application, the inert gas should be injected at a distance of 5 to 20 cm before the polymer melt enters the calendering nip, and the melt temperature should be higher than the melting temperature of the polymer melt by 10℃ to 30℃.

[0113] Specifically, the present application quantitatively correlates the material properties by determining the rheological coefficient, which can capture the changes in melt strength and viscosity caused by formulation fluctuations, and can also correlate the influence of such changes on the forming behavior of the gas in the melt, thereby improving the predictability and success rate of the gas film structure forming. The first gas injection mode (continuous and stable) or the second gas injection mode (intermittent pulse) avoids defects such as excessive merging of gas pores, structure collapse or insufficient foaming caused by mismatch between process and material, prevents problems such as unstable and fluctuating sound insulation and thermal insulation performance of the product caused by this, ensures that the gas pore structure can be accurately constructed according to the preset target, reduces the rate of substandard products, enhances the adaptability of the production process to different formulation systems and the uniformity of product performance, and ensures the high reliability of the final composite layer function.

[0114] Specifically, the process of calendering and stretching the gas-containing polymer melt at a preset stretching rate and a preset nip to form a home decoration environment-friendly composite layer preliminary blank with a gas film structure includes,

[0115] The gas-containing polymer melt is guided between a pair of counter-rotating heated rollers;

[0116] The gas-containing polymer melt is calendered and longitudinally stretched to form a home decoration environment-friendly composite layer preliminary blank containing flat strip-shaped channels or stacked air bags through the preset nip of the heated rollers at a preset stretching rate.

[0117] In the embodiment of the present application, the preset stretching rate is in the range of [3, 15] m / min, preferably 8 m / min, and the preset nip is in the range of [1.0, 5.0] mm, preferably 2.5 mm, but the above values are not limited thereto, and the skilled person in the art can also adjust the values according to actual needs.

[0118] Referring to Figure 4 As shown in the step flow chart for determining whether the air film development of the home decoration environment-friendly composite layer preliminary blank is qualified in the embodiment of the present application.

[0119] Specifically, the process of obtaining the sound wave attenuation coefficients of a plurality of preset points of the home decoration environment-friendly composite layer preliminary blank to determine whether the air film development of the home decoration environment-friendly composite layer preliminary blank is qualified comprises,

[0120] ultrasonic pulses are emitted to the plurality of preset points of the home decoration environment-friendly composite layer preliminary blank to obtain the ultrasonic signal amplitude values of the plurality of preset points of the home decoration environment-friendly composite layer preliminary blank;

[0121] a plurality of sound wave attenuation coefficients are calculated based on the plurality of ultrasonic signal amplitude values, and a sound wave attenuation coefficient standard deviation is calculated;

[0122] the sound wave attenuation coefficient standard deviation is compared with a preset sound wave attenuation coefficient standard deviation;

[0123] if the sound wave attenuation coefficient standard deviation is greater than or equal to the preset sound wave attenuation coefficient standard deviation, it is determined that the air film development of the home decoration environment-friendly composite layer preliminary blank is unqualified;

[0124] if the sound wave attenuation coefficient standard deviation is less than the preset sound wave attenuation coefficient standard deviation, it is determined that the air film development of the home decoration environment-friendly composite layer preliminary blank is qualified.

[0125] In the embodiment of the present application, the value range of the preset sound wave attenuation coefficient standard deviation determined based on the historical process is [0.05, 0.20] dB / cm, and is preferably set to 0.12 dB / cm, but the above value is not limited thereto, and the skilled person in the art can also adjust the value according to actual needs.

[0126] Specifically, the present application evaluates and determines the air film development state through acoustic wave detection, realizes accurate diagnosis of the uniformity of the internal structure, which can capture the microscopic structural defects such as local pore merging and missing caused by uneven inert gas injection or mismatched calendering parameters, and can also associate the influence of the setting of the preset stretching rate and the preset roll gap on the air film morphology and distribution, thereby improving the accuracy of the pre-judgment of the sound insulation and heat preservation performance of the product, avoiding the continuous production of unqualified products and batch waste of raw materials caused by late quality inspection, identifying air film structure abnormalities in advance, providing reliable decision basis for subsequent process adjustment, ensuring the reliability of the performance of the home decoration environment-friendly composite layer product and the stability between batches, reducing the risk of market returns, and enhancing the stable production of the production line.

[0127] Specifically, in response to the unqualified air film development of the home decoration environment-friendly composite layer initial blank, the process of determining the air film development unqualified factor by comparing the gravity center frequency offset of the home decoration environment-friendly composite layer initial blank with the preset gravity center frequency offset includes,

[0128] Emitting ultrasonic pulses to several preset points of the unqualified home decoration environment-friendly composite layer initial blank to obtain an ultrasonic echo time domain signal;

[0129] Obtaining a power spectrum of the echo signal by fast Fourier transform to calculate the gravity center frequency offset;

[0130] Comparing the gravity center frequency offset with the preset gravity center frequency offset;

[0131] If the gravity center frequency offset is greater than the preset gravity center frequency offset, it is determined that the air film development unqualified factor is the pore size;

[0132] If the gravity center frequency offset is less than or equal to the preset gravity center frequency offset, it is determined that the air film development unqualified factor is the pore distribution.

[0133] In the embodiment of the application, the preset gravity center frequency offset is in the range of [0.02, 0.08], and is preferably set to 0.05, but the above value is not limited thereto, and the skilled person in the art can also adjust the value according to actual needs.

[0134] In the embodiment of the application, the gravity center frequency offset = (F0-Fc) / F0, wherein F0 is a reference gravity center frequency value, and Fc is a gravity center frequency value. The frequency value of each frequency component fi and pi is the corresponding power spectrum amplitude, and i is the frequency point index after the power spectrum is discretely sampled.

[0135] In the embodiment of the application, the center frequency of the ultrasonic probe used is 5 MHz, the power spectrum is obtained by fast Fourier transform of the obtained echo signal, and the effective frequency range of the spectrum analysis is preferably set to 2 MHz to 10 MHz.

[0136] In the embodiment of the application, the reference gravity center frequency value F0 is a parameter calibrated before the method is implemented, and the acquisition method is as follows: a batch of home decoration environment-friendly composite layer initial blanks are produced, and it is confirmed through destructive detection that the air film structure is uniform and qualified, the ultrasonic probe, frequency and analysis settings are the same as those of the online detection, ultrasonic detection is carried out, and the gravity center frequency Fc of each sample is calculated, and the arithmetic average value of the Fc values of all qualified samples is determined as the reference gravity center frequency value F0 of the production line and the product.

[0137] It can be understood that the air hole size is greater than the preset barycentric frequency offset, which means that the high-frequency sound wave component has been abnormally attenuated according to the ultrasonic physical principle, that is, the overall air hole size is large. The air hole distribution is less than or equal to the preset barycentric frequency offset, which means that the air hole size distribution is poor, and there is a phenomenon of air hole loss and agglomeration.

[0138] Specifically, the process of adjusting the calendering and stretching parameters based on the air film development unqualified factors includes,

[0139] Based on the air hole size, the roll gap adjustment amount is determined to increase the preset roll gap;

[0140] Based on the air hole distribution, the stretching rate adjustment amount is determined to reduce the preset stretching rate;

[0141] Wherein, the roll gap adjustment amount is determined based on the relative deviation rate of the barycentric frequency offset, and the stretching rate adjustment amount is determined based on the relative deviation rate of the sound wave attenuation coefficient standard deviation.

[0142] In the embodiment of the application, the roll gap adjustment amount is k1×relative deviation rate of barycentric frequency offset×preset roll gap, and the stretching rate adjustment amount is k2×relative deviation rate of sound wave attenuation coefficient standard deviation×preset stretching rate. The value range of roll gap adjustment coefficient k1 is [0.05, 0.15], preferably 0.10, and the value range of stretching rate coefficient k2 is [0.10, 0.20], preferably 0.15, but the above values are not limited thereto, and the values can be adjusted according to actual needs by those skilled in the art.

[0143] Specifically, the application diagnoses the air film development unqualified of the home decoration environment-friendly composite layer initial blank through the acoustic index of the barycentric frequency offset, realizes the tracing and classification of the air film development unqualified factors. This can capture the macro trend of the overall large air hole size caused by insufficient calendering, and can also associate the uniformity problem of the air hole size distribution caused by the stretching rate, improve the accuracy of the production problem attribution, avoid the blindness and trial and error cost of subsequent production method adjustment, prevent the further deterioration of the home decoration environment-friendly layer initial blank structure or the generation of new defects caused by the misuse of single adjustment strategy, ensure the effectiveness of process optimization and the ability of qualified product output, reduce the continuation of unqualified products, and enhance the self-healing ability level of the production method in the face of fluctuations.

[0144] Specifically, in response to the air film development of the home decoration environment-friendly composite layer initial blank, the process of determining the air film structure of the home decoration environment-friendly composite layer initial blank by introducing the home decoration environment-friendly composite layer initial blank into the cooling setting machine for preset temperature cooling treatment includes,

[0145] The house decoration environment-friendly composite layer initial blank is guided to a set of cooling rollers with preset temperatures decreasing in turn;

[0146] The house decoration environment-friendly composite layer initial blank is made to travel along the transmission path of the cooling rollers at a preset cooling rate, and the temperature of the house decoration environment-friendly composite layer initial blank is reduced below the glass transition temperature of the polymer base material through heat dissipation by conduction, so that the internal air film structure is solidified and locked, and the house decoration environment-friendly composite layer is obtained.

[0147] In the embodiment of the present application, the preset temperature is in the range of [20℃, 70℃] and decreases in turn along the direction of travel of the house decoration environment-friendly composite layer initial blank, and the preferred setting is [70℃, 45℃, 25℃]. The preset cooling rate is in the range of [5, 30]℃ / min, and the preferred setting is 15℃ / min, but the above values are not limited thereto, and the skilled person in the art can also adjust the values according to actual needs.

[0148] Specifically, the present application realizes the smooth solidification and permanent locking of the air film structure by controlling the cooling and shaping process through preset temperature and preset cooling rate. This can capture and adapt to the differences in inherent glass transition temperature and crystallization characteristics of different polymer melts, and can also correlate and eliminate the structure rebound tendency caused by residual thermal stress of the initial blank after calendering and stretching, improve the structure fidelity from metastable state to final product, avoid the risk of structure instability caused by uneven cooling, such as product warping, deformation and internal stress concentration, and prevent problems such as air hole wall rupture, structure collapse or insufficient crystallinity caused by too fast or too slow cooling, and ensure that the lightweight high-strength, soundproof and heat-insulating functional air film structure is completely and stably retained in the final product. Embodiment 1

[0149] The polylactic acid (PLA, 4032D) 70 parts, 120 mesh wood powder (after drying) 25 parts, antioxidant 1010 (thermal stabilizer) 3 parts, and nano calcium carbonate (nucleating agent) 2 parts are weighed by weight parts, placed in a high-speed mixer, mixed at 500 revolutions per minute for 2 minutes, then raised to 1300 revolutions per minute, the material is heated to 90℃ for 3 minutes, and the mixture is obtained after cooling;

[0150] The mixture is added to a twin-screw extruder, the screw speed is set to 250 rpm, the temperature gradient is 160℃ / 175℃ / 190℃, the characteristic absorption peak intensity data sequence (about 1930nm) related to the hydroxyl group of the wood powder in the wave band of 1450~2100nm is continuously monitored at a sampling frequency of 5Hz, and the standard deviation is 0.08. Based on the fact that the standard deviation is less than the preset standard deviation (0.12), it is determined that the uniformity is qualified.

[0151] The fiber volume fraction (0.18) of the polymer melt and the intrinsic viscosity (1.2 dL / g) of the PLA are obtained, and the rheological coefficient is calculated to be 0.216, which is less than the preset rheological coefficient (0.45). The first gas injection mode is selected, the melt is introduced into the front zone of the calender, and high-purity nitrogen gas is continuously injected at a constant flow rate of 0.25 L / min under a pressure of 1.5 Bar to form a gas-containing polymer melt;

[0152] The gas-containing melt is guided between a pair of heated rollers (temperature 170℃), and the initial preset stretching rate is set to 8 m / min, and the preset roll gap is set to 2.5 mm to form a primary blank by calendering stretching, and a multi-probe ultrasonic detection device is used to emit ultrasonic waves at 5 equidistant points in the width direction of the primary blank, and the sound wave attenuation coefficients are measured to be: 1.25, 1.28, 1.22, 1.26, and 1.24 dB / cm, and the standard deviation is calculated to be 0.022 dB / cm, which is less than the preset standard deviation (0.12 dB / cm) to determine that the gas film development is qualified.

[0153] The primary blank with qualified gas film development is introduced into a three-stage cooling roller, and the temperatures are set to 70℃, 45℃, and 25℃ in sequence, and the cooling rate is about 15℃ / min, so that the material temperature is reduced below the glass transition temperature of PLA (about 55℃), and the gas film structure is solidified to obtain a home decoration environment-friendly composite layer.

[0154] Comparative Example 1

[0155] The same proportions of PLA, wood powder, antioxidant 1010, and nano calcium carbonate as in Example 1 are weighed. An additional 1.5 parts of azodicarbonamide (AC) chemical foaming agent is added, and all raw materials are mixed in the same high-speed mixer according to the same process;

[0156] The mixed material is added to the same twin-screw extruder, and the same process parameters (screw speed 250 rpm, temperature gradient 160 / 175 / 190℃) are set. In this process, the AC foaming agent is decomposed by heat to produce nitrogen gas for foaming in the melt, and there is no online monitoring;

[0157] The foamed melt is directly introduced into the same calender (roller temperature 170℃), and calendering stretching is performed at a fixed speed of 8 m / min and a roll gap of 2.5 mm to form a primary blank;

[0158] The primary blank is solidified and shaped by the same cooling process as in Example 1.

[0159] Table 1: Performance Test Results

[0160] ;

[0161] In the embodiment of the present application, the coefficient of variation of the pore diameter of Example 1 is only 15%, which is much lower than that of Comparative Example 1 (58%), proving that the present application realizes the highly uniform distribution of the pore size by online homogenization monitoring and intelligent gas injection, effectively inhibiting the merging and collapse. Benefiting from the uniform and fine gas film structure, Example 1 is significantly superior to Comparative Example 1 in sound insulation volume and tensile strength, which shows that the controllable gas film structure can not only improve the functionality but also ensure the mechanical integrity of the material. The VOC content of Example 1 is extremely low, meeting the environmental protection requirements. However, the VOC detection value of Comparative Example 1 is relatively high due to the use of chemical foaming agent, which has potential environmental and health risks.

[0162] So far, the technical solutions of the present application have been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art can easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to the related technical features without deviating from the principles of the present application, and the technical solutions after these changes or replacements will all fall within the protection scope of the present application.

Claims

1. A production method of an environmentally friendly composite layer for home decoration based on a gas film structure, characterized in that, The application relates to a method for preparing a home decoration environment-friendly composite layer. The method comprises the following steps: placing a preset proportion of biodegradable polymer resin, plant fiber filler, heat stabilizer and nucleating agent in a high-speed mixer to obtain a mixture; placing the mixture in a double-screw extruder to melt and plasticize the mixture at a preset screw rotation speed and a preset gradient temperature to obtain a polymer melt, and acquiring a characteristic absorption peak intensity data sequence of the mixture during the melt and plasticization process to calculate the standard deviation of the characteristic absorption peak intensity of the mixture; determining whether the uniformity of the mixture is qualified based on the standard deviation of the characteristic absorption peak intensity to adjust the preset screw rotation speed; in response to the uniformity of the mixture being qualified, placing the polymer melt in a calendering machine containing at least one inert gas injection device, acquiring the fiber volume fraction and the resin inherent viscosity of the polymer melt to calculate the rheological coefficient, determining the gas injection mode, and injecting the polymer melt into the gas to form a gas-containing polymer melt in response to the gas injection mode; calendering and stretching the gas-containing polymer melt at a preset stretching rate and a preset roll gap to form a home decoration environment-friendly composite layer initial blank with a gas film structure, and acquiring the acoustic wave attenuation coefficient of a plurality of preset point positions of the home decoration environment-friendly composite layer initial blank to determine whether the gas film development of the home decoration environment-friendly composite layer initial blank is qualified; in response to the gas film development of the home decoration environment-friendly composite layer initial blank being qualified, determining that the home decoration environment-friendly composite layer initial blank is introduced into a cooling and setting machine to be treated at a preset temperature to fix the gas film structure, and obtaining a home decoration environment-friendly composite layer. The preset proportion is that the biodegradable polymer resin is 60-80 parts by weight, the plant fiber filler is 20-40 parts by weight, the heat stabilizer is 1-5 parts by weight, and the nucleating agent is 0.5-3 parts by weight. The process of calculating the standard deviation of the characteristic absorption peak intensity of the mixture comprises the following steps: continuously collecting the near-infrared spectrum of the mixture during the melt and plasticization process at a preset frequency on the melt flow channel of the extruder die; reading a plurality of absorbance values at characteristic wavelengths in the 1450-2100 nm wavelength band; the absorbance values are the characteristic absorption peak intensity; and calculating the standard deviation of the characteristic absorption peak intensity collected in a preset time length. The process of determining whether the uniformity of the mixture is qualified to adjust the preset screw rotation speed comprises the following steps: comparing the standard deviation of the characteristic absorption peak intensity with a preset standard deviation; based on the standard deviation of the characteristic absorption peak intensity being less than or equal to the preset standard deviation, determining that the uniformity of the mixture is qualified to obtain the polymer melt; based on the standard deviation of the characteristic absorption peak intensity being greater than the preset standard deviation, determining that the uniformity of the mixture is not qualified; and in response to the uniformity of the mixture being not qualified, calculating the relative deviation value of the standard deviation of the characteristic absorption peak intensity and the preset standard deviation to determine the rotation speed adjustment amount to increase the preset screw rotation speed, wherein the relative deviation value is positively correlated with the rotation speed adjustment amount. The process of determining the gas injection mode comprises the following steps: determining the rheological coefficient based on the product of the fiber volume fraction and the resin inherent viscosity; comparing the rheological coefficient with a preset rheological coefficient; and determining the gas injection mode based on the comparison result. ​ ​ 2. The method for producing an environmentally friendly composite layer for home decoration based on a gas film structure according to claim 1, characterized in that, ​ ​ ​ ​ ​ 3. The method of claim 2, wherein the method further comprises: ​ ​ ​ ​ ​ ​ 4. The method for producing an eco-friendly composite layer for home decoration based on an air film structure according to claim 1, wherein ​ ​ ​ determining the gas injection mode as the first gas injection mode based on the rheological coefficient being less than the preset rheological coefficient; determining the gas injection mode as the second gas injection mode based on the rheological coefficient being greater than or equal to the preset rheological coefficient, wherein, the first gas injection mode is a continuous injection of inert gas into the polymer melt at a pressure of 1.5 Bar and a flow rate of 0.25 L / min, and the second gas injection mode is a pulsed injection of inert gas into the polymer melt at a pressure of 2 Bar, a pulse injection duration of 0.5 seconds, a single pulse injection volume of 0.2 mL, and an inter-pulse duration of 2.0 seconds, and the gas-containing polymer melt is formed in response to the first gas injection mode or the second gas injection mode.

5. The method for producing an eco-friendly composite layer for home decoration based on an air film structure according to claim 1, wherein The biodegradable polymer resin includes one or more of a blend of polylactic acid, polyhydroxyalkanoate, polybutylene succinate, polybutylene adipate, and polybutylene terephthalate.

6. The method of claim 5, wherein the method further comprises the step of: The process of determining the formation of the home environment-friendly composite layer preform with a gas film structure includes: ​ guiding the gas-containing polymer melt between a pair of counter-rotating heated rollers; drawing and stretching the home environment-friendly composite layer preform containing flat strip-shaped channels or stacked air bags through a preset nip of the heated rollers at a preset draw rate.

7. The method of claim 1, wherein the method further comprises: The process of determining whether the gas film development of the home environment-friendly composite layer preform is qualified includes: ​ emitting ultrasonic pulses to a plurality of preset points of the home environment-friendly composite layer preform to obtain ultrasonic signal amplitude values of the plurality of preset points of the home environment-friendly composite layer preform; calculating a plurality of sound wave attenuation coefficients based on the plurality of ultrasonic signal amplitude values, and calculating a sound wave attenuation coefficient standard deviation; comparing the sound wave attenuation coefficient standard deviation with a preset sound wave attenuation coefficient standard deviation; determining that the gas film development of the home environment-friendly composite layer preform is unqualified based on the sound wave attenuation coefficient standard deviation being greater than or equal to the preset sound wave attenuation coefficient standard deviation; determining that the gas film development of the home environment-friendly composite layer preform is qualified based on the sound wave attenuation coefficient standard deviation being less than the preset sound wave attenuation coefficient standard deviation.

8. The method for producing an eco-friendly composite layer for home decoration based on an air film structure according to claim 1, wherein The plant fiber filler is a mixture of one or more of dried and pulverized natural plant fibers, including wood powder, bamboo powder, rice husk powder, straw powder, and coconut shell powder, and the particle size of the plant fiber filler is 80 to 300 mesh.

9. The method of claim 7, wherein the method further comprises: providing a plurality of air film structures; and providing a plurality of environmental protection composite layers; and combining the plurality of air film structures and the plurality of environmental protection composite layers to form the air film structure-based environmental protection composite layer. The process of adjusting the drawing and stretching parameters in response to the unqualified gas film development of the home environment-friendly composite layer preform includes: determining a nip adjustment amount to increase the preset nip based on the pore size; determining a draw rate adjustment amount to decrease the preset draw rate based on the pore distribution, wherein, the nip adjustment amount is determined based on the relative deviation rate of the center of gravity frequency offset, and the draw rate adjustment amount is determined based on the relative deviation rate of the sound wave attenuation coefficient standard deviation.

10. The method of claim 8, wherein the method further comprises the step of: The process of obtaining the home environment-friendly composite layer includes: ​ guiding the home environment-friendly composite layer preform to a set of cooling rollers with a preset temperature sequentially decreasing; The initial blank of the environmentally friendly home decoration composite layer is made to move along the conveying path of the cooling roller at a preset cooling rate. The temperature of the initial blank of the environmentally friendly home decoration composite layer is reduced to below the glass transition temperature of the polymer substrate through conduction heat dissipation, and the internal air film structure is solidified and locked to obtain the environmentally friendly home decoration composite layer.

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