A mineral fibre product comprising a polymeric coating and a method for its production and use

Abstract

The present application discloses a kind of mineral fiber products containing polymer coating and its preparation method and application.Mineral fiber product as substrate and polymer coating on at least one surface of the mineral fiber product, the polymer coating is the three-dimensional porous network structure formed by thermoplastic resin fiber on the surface of mineral fiber product, and the polymer coating and mineral fiber product are not contained adhesive layer between.Relative to traditional mineral fiber product, the mineral fiber product composite structure containing polymer coating provided by the present application has the following advantages: surface protection and anti-fiber performance advantage, solves the problem of floating fiber falling during use and cutting;Surface with polymer coating has better touch, so that the use experience is better.

Description

Technical Field

[0001] This invention belongs to the field of surface treatment technology of mineral fiber thermal insulation materials, specifically relating to a mineral fiber product containing a polymer coating, its preparation method, and its application. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Traditional rock wool boards, as well as slag wool, glass wool, and other products, are pure mineral fiber products, which have defects such as surface fiber shedding, dust pollution, low strength, no filtration function, and the need for additional cloth / adhesive protection.

[0004] To improve its performance, existing technologies offer mineral fiber coatings. These coatings mix mineral fibers (such as rock wool, slag wool, and glass wool) with adhesives and are then sprayed onto the surface of substrates used in buildings, locomotives, and ships using specialized equipment. After natural drying, a seamless, stable, and airtight coating is formed. This coating possesses excellent properties such as thermal insulation, sound absorption and noise reduction, and fire resistance, making it a novel energy-saving and environmentally friendly material. However, this type of structure also suffers from poor air permeability and lack of filtration, limiting its application range. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a mineral fiber product containing a polymer coating, its preparation method and application.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a mineral fiber article containing a polymer coating, comprising a mineral fiber article as a substrate and a polymer coating located on at least one surface of the mineral fiber article, wherein the polymer coating is a three-dimensional porous network structure formed by thermoplastic resin fibers on the surface of the mineral fiber article, and there is no adhesive layer between the polymer coating and the mineral fiber article.

[0007] Preferably, the mineral fiber product is at least one of rock wool board, rock wool felt, slag wool board, or glass wool board.

[0008] This product uses mineral fiber products as the base material and a thermoplastic microfiber mesh coating on its surface. While retaining the original core properties of rock wool such as heat insulation, fire resistance, and sound absorption, it also has the advantages of dust prevention and fiber shedding prevention, thus making up for the shortcomings. It can basically directly replace conventional rock wool boards in various scenarios.

[0009] In general applications, traditional rock wool boards are the main material due to their low cost. However, in order to meet specific requirements such as dust filtration, fiber shedding prevention, and high bonding strength, the composite mineral fiber products of this invention can be used as the main consumables.

[0010] In a second aspect, the present invention provides a method for preparing a mineral fiber product containing a polymer coating, comprising the following steps: Step 1, Substrate Pretreatment: The mineral fiber substrate is subjected to dust removal, impurity removal, preheating and dehumidification treatment to remove floating fibers, oil and impurities on the substrate surface, regulate the substrate surface temperature, and improve the wetting and bonding force of the melt interface. Step 2, polymer melting and homogenization: Thermoplastic polymer or functionally modified thermoplastic polymer granules are fed into a melt extrusion device, heated at a constant temperature for plasticization and degassing, and a stable polymer melt with uniform viscosity is prepared. Step 3, in-situ hot melt mesh spraying: The homogeneous melt is extruded through a meltblown die and stretched and refined into micron-sized hot melt fibers by high temperature and high pressure airflow. The hot melt fibers are directly sprayed and deposited on the surface of the mineral fiber substrate in a semi-molten state. The fibers self-overlap to form a three-dimensional porous mesh coating, and the hot melt fibers and mineral fibers achieve physical interlocking and hot melt bonding. Step 4: Online heating for consolidation and shaping. The substrate with the mesh coating is heated online, rolled, and then air-cooled for shaping. Step 5, Cutting the finished product: The pre-formed composite substrate is cut as needed, and the rock wool felt is rolled up to complete the preparation of mineral fiber products with polymer coating.

[0011] Preferably, step 1 includes regulating the surface temperature of the substrate by heating the surface temperature of the substrate and maintaining it at 50~70°C.

[0012] Preferably, in step 2, the polymer granules are selected from at least one of polyester, polyamide, polypropylene, and polyvinyl acetate.

[0013] Preferably, in step 3, the airflow pressure is 0.2 MPa ~ 0.5 MPa; the airflow velocity is 400 m / s ~ 580 m / s; the airflow angle is 50° ~ 70°; and the airflow temperature is 250° ~ 350°.

[0014] Coating surface density: 10~60g / m 2 The optimal concentration is 10-15 g / m³. 2 .

[0015] Preferably, in step 4, the substrate with the mesh coating is heated by online hot air or infrared heat, and at the same time, it is subjected to light pressure stabilization roller pressing to strengthen the fiber overlap points and the coating-substrate interface bonding force, and eliminate coating voids and loose adhesion defects; then it is air-cooled for shaping to stabilize the mesh pore structure.

[0016] Thirdly, the present invention provides a system for preparing mineral fiber articles containing a polymer coating, comprising: Includes a substrate roller conveyor for transporting mineral fiber substrate, a frame spanning the substrate roller conveyor, a dispensing container mounted on the frame, an extruder connected to the dispensing container, the dispensing container narrowing downwards and having a row of closely spaced nozzles at the bottom for extruding polymer melt; and An air supply device for supplying high-temperature, high-pressure gas to the outlet of a distribution container, the air supply device including a blower, a gas nozzle located at the outlet below the distribution container, and an air duct connecting the gas nozzle and the blower, wherein a pipe heating element is installed on the air duct.

[0017] Furthermore, it also includes a preheating device located in front of the coating device, which preheats the rock wool felt to 60~80℃ using hot air or infrared radiation.

[0018] Preferably, a suction box is provided below the substrate roller conveyor where the dispensing container is located to remove excess air blown out; the suction box is connected to a suction pump via an air extraction pipe. A front alignment baffle is also provided behind the dispensing device to align the mineral fiber roll front to back; left and right alignment baffles are provided on both sides to align the mineral fiber roll left to right.

[0019] Preferably, the gas nozzle includes a main pipe connected to the air pipeline and several branch nozzles connected to the main pipe. The gas outlet of the branch nozzle is located at the nozzle at the bottom of the distribution container, corresponding one-to-one with the nozzle at the bottom of the distribution container, providing a high-temperature, high-pressure airflow to disperse the high-temperature polymer melt falling at the nozzle.

[0020] Furthermore, the branch nozzle sprays airflow obliquely downwards.

[0021] Preferably, in the gas nozzle, a slider is fixedly connected to the transverse screw via a main pipe and a connecting rod, and a slide rail is provided at the bottom of the frame for the transverse movement of the slider. The transverse screw moves laterally and reciprocates, driving the gas nozzle to provide a transversely varying airflow to the polymer melt.

[0022] The drive structure of the transverse screw is a cylindrical cam structure located at one end of the transverse screw, which realizes the transverse reciprocating movement of the gas nozzle. Combined with the uniform feeding of the substrate on the substrate roller conveyor, the polymer fibers are evenly spread onto the substrate surface. The substrate can be a continuous roll or a segmented sheet with process gaps. By controlling the spraying stroke and the substrate feed speed, the coating is ensured to uniformly cover the target substrate area.

[0023] The preparation system further includes a heating device, a rolling device, and an air-cooling and shaping device located behind the dispensing container. The heating device provides hot air or infrared radiation to heat the composite product. A rolling device with a pressure-stabilizing roller is also located behind the dispensing container, applying a light pressure of 0.1~0.2 MPa to enhance the interfacial bonding between the coating and the rock wool felt and to flatten the surface. The air-cooling and shaping device provides room-temperature air to the product to promote rapid cooling and obtain a stable structure. The above equipment can be selected from commonly used instruments or devices as needed, and is not limited in this invention.

[0024] Fourthly, the present invention provides the application of the mineral fiber products containing polymer coatings described in the first aspect in building thermal insulation and sound insulation, industrial equipment heat insulation, and air purification and dust removal.

[0025] The composite board of this invention can directly replace traditional rock wool board and is widely used in building insulation and sound insulation, industrial equipment heat insulation, air purification and dust removal and other fields; it is suitable for general occasions and can also meet special requirements such as clean dust prevention, air filtration, and airtight environmental protection.

[0026] The composite material of this invention satisfies five basic properties: low calorific value, high interfacial bonding strength, excellent anti-fiber shedding ability, high air permeability, and excellent tensile strength. On the other hand, when facing special scenarios such as filtration, high temperature, and sealed interiors, it is additionally matched with special indicators such as particulate matter filtration efficiency, temperature resistance, low VOC volatility, and surface flexibility.

[0027] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows: This invention provides a mineral fiber product with a polymer coating. The polymer forms a network structure on the surface of the mineral fiber product, which realizes the interlacing of fibers and rich porosity on the surface of the substrate, resulting in good strength, heat resistance and structural stability.

[0028] The mineral fiber product containing a polymer coating provided by this invention does not require adhesive bonding between the polymer coating and the mineral fiber product. The two are self-adhesive composite by in-situ melt-blowing and hot-melt spraying of thermoplastic polymer to form a web. The coating and the mineral fiber substrate can be bonded by the hot-melt interlocking of the polymer melt and the overlapping bonding of the fibers. No additional adhesive is needed as an intermediate bonding medium. It has the core advantages of integrated structure, porous, environmentally friendly and efficient. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0030] Figure 1This is an overall structural diagram of the preparation system for the mineral fiber product containing a polymer coating in Example 1.

[0031] Figure 2 This is a schematic diagram of the gas nozzle structure of the preparation system for the polymer-coated mineral fiber product in Example 1.

[0032] Figure 3 This is a schematic diagram of the transverse screw drive structure.

[0033] Figure 4 A photograph of a mineral fiber product with a polymer coating provided for this invention.

[0034] Among them, 1-substrate roller conveyor, 2-frame, 3-dispensing container, 4-extruder, 5-blower, 6-gas nozzle, 7-air duct, 8-pipeline heating element, 9-suction box, 10-extraction duct, 11-front alignment baffle, 12-polymer fiber filament, 13-pressure stabilizing roller, 14-air-cooled shaping equipment, 15-mineral fiber substrate, 16-polymer coating; 601-Main pipe, 602-Branch nozzle, 603-Transverse screw, 604-Slider, 605-Slide rail, 606-Fixing block, 607-Drive frame, 608-Cylindrical cam, 609-Limit block. Detailed Implementation

[0035] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0036] In existing technologies, composite mineral fiber products generally rely on phenolic resin adhesive as an intermediate bonding layer to secondarily bond the pre-formed nonwoven fabric with the mineral fiber substrate. The adhesive layer will form an obvious bonding layer at the interface, and the air permeability will be affected by the blockage of the adhesive liquid. There is also the risk of adhesive layer aging, embrittlement, and interface delamination. At the same time, it has high surface density, high calorific value, low air permeability, and poor bonding stability to prevent fiber scattering at the interface.

[0037] To address the aforementioned issues, this invention employs an in-situ integrated molding process. Using mineral fiber materials such as rock wool boards and fiberglass cloth as the substrate, the surface undergoes simultaneous microfiber molding and coating application. Compared to the traditional method of first fabricating nonwoven fabric and then bonding it, the interfacial bonding strength is significantly improved. The resulting substrate exhibits interwoven fibers and abundant pores, resulting in excellent strength, heat resistance, and stability. During production, the substrate is driven by a conveyor, moving smoothly forward at a speed of 6–10 m / min. The polymer melt is extruded through a die and stretched and refined by high-temperature, high-speed airflow on both sides, forming semi-molten microfibers. The die is then sprayed vertically onto the substrate and moves back and forth along its width, ensuring the fibers are evenly distributed onto the substrate surface. The microfibers, carrying residual heat, not only thermally fuse with the mineral fiber surface but also penetrate into the fiber gaps of the substrate, forming a robust interlocking structure upon cooling. The entire process requires no additional adhesives; the coating and substrate are fused together, resulting in a dense and uniform structure, fundamentally preventing delamination and detachment. Specifically, compared with traditional mineral fiber products, the composite structure of mineral fiber products with polymer coating provided by this invention has the following advantages: 1. The surface protection and anti-fiber-shedding performance have advantages, which solves the problem of loose fibers falling off during the use and cutting of mineral fiber products; the surface with polymer coating has a better feel and a better user experience.

[0038] 2. Advantages in fire resistance and combustion performance: The composite board of this invention does not require the addition of flammable adhesives such as phenolic resin during preparation, and its calorific value per unit area is only 0.3~0.45 MJ / m². 2 It is far inferior to traditional adhesive composite rock wool boards, has stronger fire safety, and meets the requirements of high-level fire protection conditions.

[0039] 3. Advantages in mechanical and structural stability: The coating of the composite board of the present invention is thermally fused with the substrate, and the overall tensile strength is much higher than that of traditional adhesive composite rock wool board. This is because the coating of the composite board of the present invention is formed by physical fusion and thermal fusion, and the coating is difficult to separate from the substrate. It has good structural uniformity, and in-situ spraying can achieve uniform coverage of the main plane of the substrate without dead corners, with consistent thickness and fiber distribution throughout the entire area.

[0040] 4. Advantages in air permeability and porosity retention: The composite board of the present invention has good pore connectivity in its ultra-fine fiber mesh coating, and will not have the phenomenon of pore blockage by adhesive layer as seen in traditional glued and film-coated rock wool boards. The air permeability of the finished product is basically no different from that of the original rock wool substrate.

[0041] 5. Additional Functional Advantages: Original rock wool boards only have basic functions of heat insulation, sound insulation, and heat preservation; the composite board of this invention has an ultra-fine fiber coating with excellent particulate matter filtration capabilities, achieving the combination of heat insulation, sound insulation, and primary air purification and dust prevention functions, making it a multi-purpose product and expanding its application range.

[0042] 6. Environmental protection and weather resistance advantages: Green and non-volatile, the entire manufacturing process is solvent-free, formaldehyde-free, and VOC-free, and will not release harmful gases during use, making it suitable for enclosed spaces such as building interiors, rail transit, and ships; Excellent aging resistance, does not contain easily aging organic adhesive layers, and under the long-term effects of temperature changes, humidity, and airflow, its weather resistance and service life are significantly better than traditional adhesive composite rock wool products.

[0043] 7. Advantages of Process Derivative Applications: The composite board of this invention is integrally molded, eliminating the need for subsequent additional fabric covering or adhesive application. On-site installation and secondary processing are significantly simplified; furthermore, the coating can be adjusted according to working conditions during continuous production, resulting in greater customization capabilities.

[0044] The present invention will be further described below with reference to the embodiments.

[0045] Example 1 A method for preparing mineral fiber products containing a polymer coating includes the following steps: 1. Melting and plasticizing thermoplastic raw materials: The raw materials are thermoplastic polymers such as polypropylene, polyethylene, and PET. These materials have the characteristics of melting and flowing when heated and solidifying when cooled, and the process is reversible and repeatable.

[0046] The specific process includes feeding granular or fragmented raw materials into an extruder, where they are melted and plasticized under the combined action of high temperature and screw shear force to form a uniform viscous melt with good flowability, providing a basis for the subsequent melt to pass through the nozzle.

[0047] 2. High-pressure airflow drawing into fibers: The melt is stretched by a high-pressure airflow to form ultrafine fibers / filaments, which is the core step in forming the "ultrafine" structure of the coating. The principle is the same as that of meltblown technology.

[0048] Molten polymer is extruded under high pressure through a narrow die nozzle. High-speed hot air streams on both sides of the nozzle impact the melt stream, causing it to be stretched and sheared rapidly, which refines the melt. The fiber diameter can reach 0.5 to 10 micrometers or even nanometers, preparing for the final formation of a network structure of ultrafine fibers or filaments. This process directly determines the filtration efficiency and specific surface area of ​​the final product.

[0049] 3. In-situ deposition on the surface of mineral fiber substrate: This step achieves the construction of a composite material between the coating and the substrate, with the core being "in-situ" molding: the fibers are directly laid onto the substrate surface during formation, rather than being made into non-woven fabric first and then composited, which can significantly enhance the interfacial bonding between the coating and the substrate. Using mineral fiber substrates such as glass fiber cloth, rock wool board, and rock wool felt as the load-bearing layer provides the coating with basic structural strength, heat resistance, and dimensional stability; the newly formed, still-heated and sticky, ultrafine fiber web falls directly onto the moving mineral fiber substrate surface, forming a dense and uniform initial coating.

[0050] 4. Online heating and rapid cooling to set the coating, forming a continuous fiber web coating: The substrate with the mesh coating is heated online by hot air or infrared heat, and then subjected to light pressure stabilization roller pressing to strengthen the fiber overlap points and the coating-substrate interface bonding force, eliminating coating voids and loose adhesion defects; then it is air-cooled to set the shape and stabilize the mesh pore structure.

[0051] In the final curing and forming stage of the coating, the thermoplastic microfiber mesh deposited on the substrate surface is rapidly cooled by natural air cooling or forced cooling system. When the temperature drops below the melting point or glass transition temperature of the polymer, the fiber mesh solidifies instantly and forms a physical anchor and bond with the surface of the mineral fiber substrate, ultimately forming a continuous and stable fiber mesh coating.

[0052] The actual product is as shown Figure 4 As shown.

[0053] This process relies on high-pressure airflow to stretch melt to form ultrafine fibers, and finally constructs an ultrafine fiber mesh coating on the surface of mineral fiber substrate. Its "ultrafine" characteristic means that the basic unit constituting the coating is micron-sized ultrafine fiber, thus forming a macroscopic structural feature that is different from conventional fabrics and ordinary coatings.

[0054] The uniformity of fiber diameter is controlled by the coordinated control of melt pressure (6.5–8.2 MPa), hot air temperature (195–298 ℃), air velocity (380–480 m / s), and production line feed speed (6–10 m / min), resulting in stable finished monofilament dimensions.

[0055] The microfibers obtained by this method have excellent flexibility. The breaking elongation rate is used as the evaluation index, and the fiber breaking elongation rate ranges from 80% to 220%. The fibers can be bent and twisted freely, and there is no permanent deformation after bending, with good resilience.

[0056] The fibers are rapidly cooled and shaped under the action of high-speed airflow, resulting in fine, flexible filaments without rigid hard filaments. Individual fibers exhibit natural bending and twisting patterns rather than being straight, creating conditions for fibers to overlap.

[0057] This product is a microporous protective coating specifically designed for the outer walls of ship hulls. It offers corrosion resistance, abrasion resistance, heat insulation, and protection against marine organism adhesion. It possesses distinct filtration characteristics, effectively intercepting 0.1–10μm suspended particulate matter, algal spores, bacteria, and marine larvae from seawater and salt spray. Its filtration performance directly determines its antifouling effect and service life. This process directly determines the filtration efficiency and specific surface area of ​​the final product.

[0058] The filtration efficiency for 0.3μm particles was tested using the method specified in GB 19083: using 0.3μm NaCl saline aerosol as the medium, at a flow rate of 85 L / min, the efficiency was calculated based on the upstream and downstream particle concentrations. 0.3μm is the most easily penetrating particle size, and this indicator is the core basis for evaluating the integrity of the coating's microporous structure and its antifouling ability.

[0059] The fiber coating is lightweight and has a loose structure. Compared to adhesive coatings and thick coatings, the coating made of stacked microfibers has a lower basis weight and thinner overall thickness. The fiber network contains numerous air cavities, resulting in a loose overall structure that avoids the hardening and compaction that occurs after adhesive curing. It exhibits excellent structural continuity and integrity, with the microfibers forming a continuous network. The entire coating surface is free of breaks and abrupt changes in density or sparseness, maintaining consistent fiber fineness and pore distribution throughout. The overall uniformity of the coating structure is far superior to traditional adhesive-coated composites and ordinary nonwoven fabric composites.

[0060] A large number of ultrafine fibers are continuously sprayed onto the surface of the substrate in a semi-molten state, and are randomly stacked and interwoven. The fibers are bonded and entangled with each other by their own thermal melting properties, forming a continuous and uninterrupted three-dimensional network without a regular warp and weft weaving structure.

[0061] The spraying direction is perpendicular to the upper surface of the substrate, and the meltblown die moves horizontally back and forth along the width of the substrate, while the substrate is synchronously and uniformly conveyed forward. A large number of ultrafine fibers are continuously sprayed onto the surface of the substrate in a semi-molten state; the fibers are randomly stacked and interwoven, and they adhere and entangle with each other by their own thermal melting properties, forming a continuous and uninterrupted three-dimensional network, without any regular warp and weft weave structure.

[0062] Due to the extremely small fiber diameter, numerous tiny and evenly distributed micropores and capillaries are formed between the fibers. The pore size decreases synchronously with the fiber fineness, resulting in high porosity, tortuous and interconnected pores. This not only preserves the porous structure but also achieves fine pore size, distinguishing it from the large-diameter structure of coarse fiber coatings.

[0063] The fine hot-melt fibers can penetrate deep into the surface gaps and fiber gaps of the mineral fiber substrate, forming a combination of physical interlocking and hot-melt bonding. The interface between the coating and the substrate is dense, with a large contact area and no obvious delamination gaps.

[0064] Through the above process, mineral fiber reinforced thermoplastic composite materials can be prepared. This material achieves complementary performance between the two substrates: the thermoplastic microfiber web on the surface of the material has a high specific surface area and excellent filtration, barrier or chemical activity; the mineral fiber substrate at the bottom of the material provides strong mechanical support, high temperature resistance and structural integrity, and has broad application potential in the fields of high-efficiency air filtration, special protection, building energy conservation and other fields.

[0065] Example 2 Preparation system for mineral fiber products with polymer coating Structure as Figure 1 As shown, the system includes a substrate roller conveyor 1 for transporting mineral fiber substrate 15, a preheating device 14, a frame 2 spanning the substrate roller conveyor 1, a distribution container 3 mounted on the frame 2, and an extrusion device connected to the distribution container 3, wherein the extrusion device is an extruder 4. It also includes an air supply device for supplying high-temperature, high-pressure gas to the outlet of the distribution container 3. The air supply device includes a blower 5, a gas nozzle 6 located below the outlet of the distribution container 3, and an air duct 7 connecting the gas nozzle 6 and the blower. A pipe heating element 8 is installed on the air duct 7. The pipe heating element 8 heats the air duct 7. As a typical embodiment, the pipe heating sleeve is a spiral heating belt. Both the air duct 7 and the pipe heating element 8 are flexible pipes / components.

[0066] The preheating device 14 preheats the rock wool felt to 60~80℃ using hot air or infrared.

[0067] A suction box 9 is installed below the substrate roller conveyor 1 where the distribution container 3 is located to remove excess air blown out; the suction box 9 is connected to a suction pump through a suction pipe 10. A front alignment baffle 11 is also installed behind the distribution device 3 to align the mineral fiber roll front and back; left and right alignment baffles are installed on both sides to align the mineral fiber roll left and right.

[0068] The front alignment baffle 11 is driven to rise or fall by a lift or rotates around its own upper axis under the drive of its control device, thereby blocking and releasing the substrate; the left and right alignment baffles can be positioned on the left and right sides of the substrate under the action of cylinders or springs.

[0069] The structure of the front alignment baffle 11 and the left and right alignment baffles can adopt the existing positioning device structure, such as the structure of the second baffle and the third baffle provided by patent CN202221275114.3, and no special settings are made in this invention.

[0070] The dispensing container 3 narrows downwards and connects to a row of closely spaced nozzles at the bottom for extruding polymer melt.

[0071] In some embodiments of the present invention, such as Figure 2 As shown, the gas nozzle 6 includes a main pipe 601 connected to an air pipeline and several branch nozzles 602 connected to the main pipe. The gas outlets of the branch nozzles 602 are located at the nozzles at the bottom of the distribution container 3, corresponding one-to-one with the nozzles at the bottom of the distribution container 3, providing high-temperature, high-pressure airflow to disperse the high-temperature polymer melt falling at the nozzles. Furthermore, the branch nozzles 602 spray airflow obliquely downwards.

[0072] In order to provide a variable-direction airflow to the high-temperature polymer melt, the present invention provides a structural arrangement in which the gas nozzle 6 moves laterally and reciprocally along the substrate roller 1.

[0073] like Figure 1 and Figure 3 As shown, in the gas nozzle 6, a slider 604 is fixedly connected to the transverse screw 603 via a connecting rod from the main pipe 601. A slide rail 605 is provided at the bottom of the frame 2 for the transverse slider 604 to move laterally. The transverse screw 603 moves laterally and reciprocates, driving the gas nozzle 6 to provide the polymer melt with a transversely varying airflow.

[0074] The driving structure of the transverse screw 603 is as follows: Figure 3 As shown, based on a cylindrical cam structure located at one end of the transverse screw 603, it includes a fixed block 606 fixed to one transverse end of the transverse screw 603, a drive frame 607, and a cylindrical cam 608 mounted on the drive frame 607. The cylindrical cam 608 rotates under the drive of the drive device, and the cam position continuously reciprocates along the axial direction of the transverse screw 603. The fixed block 606 and the drive frame 607 can be limited by a groove structure or cooperate in other ways, which will not be elaborated here. Two limiting blocks 609 are provided at the bottom of the fixed block 606 to cooperate with the cylindrical cam 608. The reciprocating movement of the cylindrical cam 608 drives the limiting blocks 609 and the fixed block 606 to move as sliders on the drive frame 607, thereby realizing the transverse reciprocating movement of the transverse screw 603, thereby realizing the transverse reciprocating change of the gas nozzle 6. Combined with the uniform feeding of the substrate on the substrate roller conveyor 1, the polymer fiber is evenly spread on the surface of the substrate. The substrate is a continuous roll or a segmented sheet with process gaps. By controlling the spraying stroke and the substrate feed speed, the coating is ensured to cover the target substrate area evenly.

[0075] The extruder 4 heats and melts a solid polymer and extrudes the melt; the polymer melt is ejected from the nozzle 9, and the gas nozzle 6 provides high-pressure hot air to stretch the polymer melt and form polymer filaments 12.

[0076] The nozzle orifice diameter of the dispensing container is 0.15-0.3mm (which can be changed according to the fiber thickness of the fiber layer), and the hot air jet angle of the gas nozzle 6 is 60°.

[0077] High-temperature and high-pressure hot airflow forms a high-speed airflow that simultaneously shears and stretches the melt stream, refining the melt into ultrafine hot melt fibers. These ultrafine hot melt fibers are then sprayed onto the surface of the substrate to form a polymer coating 16, achieving physical interlocking and interfacial hot melt bonding.

[0078] The preparation system further includes a heating device, a rolling device, and an air-cooling and shaping device located behind the dispensing container 3. The heating device can provide hot air or infrared heat to heat the composite product. In embodiments of the present invention, a gas nozzle 6 and an air duct 7 connecting the gas nozzle 6 and a blower can be used. The air duct 7 is equipped with a pipe heating element 8. The position of the gas nozzle 6 may be fixed or not. A rolling device containing a pressure-stabilizing roller 13 is then provided to apply a light pressure of 0.1~0.2MPa to enhance the bonding force between the coating and the rock wool felt interface and to flatten the surface. The air-cooling and shaping device 14 provides room temperature air to the product to promote rapid cooling and obtain a stable structure. The above equipment can be selected from commonly used instruments or devices as needed, and is not limited in this invention.

[0079] Example 3 Using the preparation system provided in Example 2, mineral fiber products with polymer coatings were prepared based on the following parameters.

[0080] 1. Key Materials (1) Substrate: Rock wool felt; (2) Coating material: polypropylene; 2. Coating surface density: 15g / m³ 2 .

[0081] (1) Melting and plasticizing stage The barrel temperature is 200℃ ~ 280℃, using a gradient heating strategy (200℃ in the feeding section and 280℃ in the melting section). Excessive temperature can lead to polymer degradation (increased MFI); excessively low temperature results in high melt viscosity, poor flowability, and easy clogging of the die head.

[0082] The melt pressure is 15 MPa to 25 MPa. Large pressure fluctuations can lead to uneven fiber diameters. Precise control using a metering pump is necessary.

[0083] Melt flow rate (MFI) for PP: ~1500, a characteristic of the raw material itself, directly affecting fiber fineness. High MFI raw materials are more likely to form ultrafine fibers.

[0084] (2) Airflow stretching stage The hot air temperature is 250℃ ~ 350℃, slightly higher than the barrel temperature, to compensate for the heat loss of the melt stream and maintain its ductility.

[0085] Hot air pressure is 0.2 MPa ~ 0.5 MPa. The higher the pressure, the faster the airflow speed, and the finer the fiber is drawn (nanoscale / microscale), but the higher the energy consumption is.

[0086] The airflow velocity is 400 m / s to 580 m / s, and the angle is 50° to 70°, which determines the fiber orientation and the uniformity of the web.

[0087] (3) Deposition and forming stage The die-to-substrate distance (DCD) is 20cm, which is the receiving distance. If the distance is too short, the fibers will not cool sufficiently and may penetrate the substrate; if the distance is too long, the fibers will scatter and the adhesion will decrease.

[0088] The substrate is heated to 60°C.

[0089] The substrate running speed is 15 m / min to control the coating weight (thickness). The slower the speed, the more fibers are deposited, and the thicker the coating.

[0090] Negative pressure adsorption, by applying negative pressure under the substrate, allows the fiber web to adhere more tightly to the surface of the mineral fiber substrate, reducing fuzzing.

[0091] (4) The heat-replenishing rolling stage and the cooling and shaping post-treatment. The substrate with the mesh coating is heated by online hot air at 60°C, and at the same time, it is subjected to light pressure stabilization roller pressing to strengthen the fiber overlap points and the coating-substrate interface bonding force, and eliminate coating hollowness and loose adhesion defects.

[0092] Then air-cooled shaping: Cooling air temperature / speed: Room temperature ~ 40℃, 300m / s rapid cooling, quickly lowering the fiber temperature below the melting point, so that it can be solidified and shaped, maintaining the ultra-fine structure.

[0093] Electret treatment (optional), 10 kV ~ 20 kV. If the coating is used for filtration (such as air filtration), permanent charges can be imparted to the fibers through electrostatic electret treatment, which can greatly improve filtration efficiency.

[0094] Based on the process parameters provided in Example 3, the fiber diameter was adjusted, and the resulting product performance parameters are as follows: 3-1: The average fiber diameter is 1.2μm, the specific surface area of ​​the finished product is 18.6m² / g, and the filtration efficiency for 0.3μm particles is 99.2%. 3-2: The average fiber diameter is 3.5μm, the specific surface area of ​​the finished product is 11.3m² / g, and the filtration efficiency for 0.3μm particles is 95.7%. 3-3: The average fiber diameter is 7.8μm, the specific surface area of ​​the finished product is 6.5m² / g, and the filtration efficiency for 0.3μm particles is 82.4%.

[0095] It is evident that the smaller the fiber diameter, the more fiber filaments there are, the larger the overall specific surface area, and the stronger the interception ability of fine particles, thus simultaneously improving filtration efficiency. By adjusting the extrusion pressure, hot air flow rate, air temperature, and die output, the fiber diameter can be precisely controlled, thereby achieving gradient customization of the finished product's specific surface area and filtration efficiency. Small-diameter fiber formulations are suitable for high-precision air purification and dust filtration scenarios, while large-diameter fiber formulations balance air permeability and basic filtration requirements, making them suitable for ventilation, dustproof, and sound insulation composite products.

[0096] Based on the material parameters in 3-1, the process conditions were adjusted, and the results are as follows: 3-4 (Heat-resistant PPS): PPS vacuum dried, melted at 270-295℃, fiber 1.6μm, filtration efficiency 99.0%.

[0097] 3-5 (General Purpose PPS): PPS screw plasticizing, airflow stretching at 275-300℃, fiber 2.1μm, filtration efficiency 98.1%.

[0098] 3-6 (Ultra-fine PPS): High melt index PPS extrusion, drawn at 280-305℃, fiber size 0.9μm, filtration efficiency 99.6%.

[0099] 3-7 (High gram weight PPS): Modified PPS molding, molding at 268-292℃, fiber 3.0μm, filtration efficiency 93.8%.

[0100] Based on the process parameters in 3-1, mineral fiber products were prepared using different polymer materials and by adjusting the coating surface density. Unless otherwise specified, the parameters were consistent with those in 3-1. The coating unit area calorific value, tensile strength, tactile feel grade, fiber shedding prevention grade, air permeability, and bonding strength of the products were tested.

[0101] The fiber shedding prevention level is tested according to the dry lint test method in GB / T 24218.10-2016. Each sample is (220±1)mm × (285±1)mm (long side along the transverse direction of the sample) and undergoes a modified Gelbo torsion method under combined torsion and compression in a test chamber. During the torsion process, air is extracted from the test chamber, and a dust particle counter is used to count the total number of lint particles between 0.3μm and 25μm. Based on the total number of lint particles, it is divided into 1 to 5 levels from low to high. The higher the level, the fewer the total number of lint particles and the better the fiber shedding prevention performance; the lower the level, the more lint particles and the easier it is for fibers and debris to fall off. The standard is as follows: Level 5: The total number of fallen fluff particles is less than 3,000, the lowest total number of fallen fluff particles, with no obvious fiber shedding; Level 4: The total number of fallen fluff particles is higher than 3000 but lower than 6000, indicating a relatively low total number of fallen fluff particles and slight fiber shedding; Level 3: Total number of fallen fluff particles is above 6000 but below 9000, indicating a moderate total number of fallen fluff particles, with localized fiber shedding. Level 2: The total number of fallen fluff particles is higher than 9,000, indicating a high level of fluff and significant fiber shedding.

[0102] Tactile grade: There is no unified evaluation standard in the mineral fiber industry. This invention refers to the testing of fabric tactile performance and uses the FTT fabric tactile tester to test the sample. The tactile performance is evaluated by the surface friction characteristics index of the sample and classified as rough (1 point), relatively rough (2 points), average (3 points), relatively smooth (4 points) and smooth (5 points).

[0103] The results are shown in Table 1: Table 1. Test results of products prepared with different parameters

[0104] The preparation process of the nonwoven fabric + phenolic resin composite layer is as follows: 1. Substrate preparation: Rock wool felt of the same material as in Example 3, and conventional polyester nonwoven fabric with a surface density similar to that of the meltblown coating (surface density approximately 15 g / m²) were selected. 2 ).

[0105] 2. Adhesive preparation: Prepare the phenolic resin adhesive into a liquid with a solid content of about 20% according to the process requirements. During the preparation process, an appropriate amount of curing agent and defoamer can be added and stirred evenly for later use.

[0106] 3. Coating and Lamination: Using roller coating or spray coating, phenolic resin adhesive is evenly coated on the surface of mineral fiber substrate. Then, non-woven fabric is flatly laminated onto the coated surface. Pressure is applied by rollers to ensure close contact between the non-woven fabric and the substrate, control the thickness of the adhesive layer to be uniform, and avoid insufficient or excessive adhesive.

[0107] 4. Curing and shaping: The composite board is placed in an oven and heated at 150℃ for 20 minutes to cure the phenolic resin completely cross-linked and cured, forming a non-woven fabric-mineral fiber composite structure with the adhesive layer as the bonding medium.

[0108] 5. Secondary processing: After cooling, the product is cut and trimmed as needed to obtain a traditional composite layer product.

[0109] This patented process increases the tensile strength of the product by an average of approximately 25% compared to traditional processes. The coating features an ultra-fine fiber mesh structure, resulting in a softer feel. The fibers self-heat and fuse into a single unit, preventing fiber shedding during friction and significantly improving anti-scattering performance compared to adhesive composite products. The product's tensile strength is approximately 25% higher than traditional products, meeting the stress requirements of filter media installation, airflow scouring, and repeated use, resulting in a more stable structure. The ultra-fine fiber mesh is soft, easy to bend and shape, and suitable for various assembly scenarios. The fibers self-heat and fuse to form a single unit; lint tests were conducted according to GB / T 24218.10-2016, and no fiber detachment was observed under friction conditions, preventing fiber contamination and ensuring long-term stable filtration performance.

[0110] The principle and influencing factors of strong adhesion are analyzed as follows: 1. Core principle of strong adhesion: This process achieves high-strength adhesion through the dual effects of physical interlocking and hot-melt interface bonding, without the addition of any external adhesives throughout the entire process. 1) Physical interlocking effect: The ultrafine fibers formed by high-pressure airflow stretching are small in diameter and highly flexible. When sprayed onto the surface of a mineral fiber substrate at a certain temperature in a semi-molten state, they can penetrate deep into the fiber gaps, micropores and recessed structures on the surface of the substrate to form a mechanically interlocking and intertwined interlocking structure, thus physically locking the coating and the substrate together.

[0111] 2) Hot melt self-adhesive effect: Thermoplastic polymer fibers are deposited and formed when they are in a semi-molten state, and thermal fusion bonding occurs at the overlap of the fibers themselves; at the same time, the high-temperature melt is in close contact with the surface of the mineral fiber, and intermolecular forces and local thermal fusion wetting are generated at the interface, so that the coating and the substrate form an integrated structure.

[0112] 3) Overall network constraint: The continuous three-dimensional mesh coating provides full coverage and tensile constraint to the substrate, allowing stress to be evenly distributed within the network and preventing localized stress concentration that could lead to interfacial delamination.

[0113] 2. Key factors affecting the strength of bonding 1) Raw material and melt state: The type of thermoplastic polymer, melting temperature, and melt viscosity directly affect the wetting effect; if the temperature is too low, the melt fluidity is poor and it cannot fully penetrate into the gaps of the substrate; if the temperature is too high, the melt is prone to degradation, the fiber toughness decreases, and the bonding force weakens.

[0114] 2) Airflow stretching process parameters: The temperature and flow rate of hot air determine the fineness of fibers and the cooling rate: if the air temperature is too low, the fibers cool down quickly and lose their heat-melting activity, resulting in poor interfacial bonding; if the air flow rate is inappropriate, the fiber thickness will be uneven, and the interlocking effect will be inconsistent.

[0115] 3) Receiving distance and negative pressure: If the spray receiving distance is too far, the fibers will only be able to stack on the surface after they have completely cooled and cannot achieve thermal fusion. If the distance is too close, the fibers will be compacted and the pores will be blocked, and the interfacial stress will increase. Reasonable negative pressure can improve fiber adhesion and strengthen mechanical bonding.

[0116] 4) Substrate condition: Dust, loose fibers, and oil on the substrate surface can prevent the melt from contacting the substrate, forming a weak interface; insufficient preheating temperature of the substrate can cause the melt to cool rapidly, reducing the wetting and bonding effect.

[0117] 5) Coating weight and linear velocity: If the coating surface density is too low, the fiber network continuity is poor and the overall constraint ability is insufficient; if the production line speed is too fast, the fiber deposition time is insufficient, the overlap and interlocking are inadequate, and the bonding strength decreases.

[0118] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A mineral fiber product containing a polymer coating, characterized in that, The invention includes a mineral fiber product as a substrate and a polymer coating on at least one surface of the mineral fiber product, wherein the polymer coating is a three-dimensional porous network structure formed by thermoplastic resin fibers on the surface of the mineral fiber product, and there is no adhesive layer between the polymer coating and the mineral fiber product.

2. The mineral fiber product containing a polymer coating according to claim 1, characterized in that, The mineral fiber product is at least one of rock wool board, rock wool felt, slag wool board or glass wool board.

3. A method for preparing mineral fiber products containing a polymer coating, characterized in that, Includes the following steps: Step 1, Substrate Pretreatment: The mineral fiber substrate is subjected to dust removal, impurity removal, preheating, and dehumidification treatment; Step 2, Polymer Melting and Homogenization: The thermoplastic polymer granules are fed into a melt extrusion device and heated to prepare a polymer melt; Step 3, In-situ hot melt web spraying: The polymer melt is extruded through a meltblown die and stretched and refined into micron-sized hot melt fibers by high temperature and high pressure airflow. The hot melt fibers are directly sprayed and deposited on the surface of the mineral fiber substrate in a semi-molten state. The fibers self-overlap to form a three-dimensional porous mesh coating, and the hot melt fibers and mineral fibers achieve physical interlocking and hot melt bonding. Step 4: Online heating for consolidation and shaping. The substrate with the mesh coating is heated online, rolled, and then air-cooled for shaping. Step 5: Cut or roll up the finished product.

4. The method for preparing a mineral fiber product containing a polymer coating according to claim 3, characterized in that, Step 1 includes controlling the surface temperature of the substrate by heating the surface temperature of the substrate and maintaining it at 50~70℃.

5. The method for preparing a mineral fiber product containing a polymer coating according to claim 3, characterized in that, In step 2, the polymer granules are selected from at least one of polyester, polyamide, polypropylene, and polyvinyl acetate.

6. The method for preparing a mineral fiber product containing a polymer coating according to claim 3, characterized in that, In step 3, the airflow pressure is 0.2 MPa ~ 0.5 MPa; the airflow velocity is 400 m / s ~ 580 m / s; the airflow angle is 50° ~ 70°; and the airflow temperature is 250° ~ 350°. Or coating surface density: 10~60g / m² 2 .

7. The method for preparing a mineral fiber product containing a polymer coating according to claim 3, characterized in that, In step 4, the substrate with the mesh coating is heated by online hot air or infrared heat, and at the same time, it is subjected to light pressure stabilization roller pressing to strengthen the fiber overlap points and the coating-substrate interface bonding force, and eliminate coating voids and loose adhesion defects; then it is air-cooled to stabilize the mesh pore structure.

8. A system for preparing mineral fiber products containing a polymer coating, characterized in that, include: It includes a substrate roller conveyor for transporting mineral fiber substrate, a frame spanning the substrate roller conveyor and a dispensing container mounted on the frame, an extruder connected to the dispensing container, the dispensing container narrowing downwards and having a row of closely spaced nozzles at the bottom for extruding polymer melt; as well as An air supply device for supplying high-temperature, high-pressure gas to the outlet of a distribution container, the air supply device including a blower, a gas nozzle located at the outlet below the distribution container, and an air duct connecting the gas nozzle and the blower, wherein a pipe heating element is installed on the air duct; Furthermore, it also includes a preheating device located in front of the coating device, which preheats the rock wool felt to 60~80°C by using hot air or infrared radiation. The transverse screw moves laterally and reciprocates, driving the gas nozzle to provide a laterally varying airflow to the polymer melt.

9. The preparation system for a mineral fiber product containing a polymer coating according to claim 8, characterized in that, It also includes a heating device, a rolling device, and an air-cooling and shaping device located behind the distribution container. The heating device provides hot air or infrared to heat the composite product. A rolling device with a pressure-stabilizing roller is also installed behind the distribution container to apply a light pressure of 0.1~0.2MPa to enhance the bonding force between the coating and the rock wool felt interface and to flatten the surface. The air-cooling and shaping device provides room temperature air to the product to promote rapid cooling and obtain a stable structure.

10. The application of the polymer-coated mineral fiber product as described in claim 1 in building thermal insulation and sound insulation, industrial equipment heat insulation, and air purification and dust removal.

Images