Composite non-woven material and preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer material recycling, in particular to a composite non-woven material and a preparation method and application thereof. According to the preparation method, full recycled materials are taken as raw materials, plasma treatment is utilized to provide an activated interface for chemical reaction, rPVB particles are prepared into rPVB fibers through regulation and control of a plasticizer, stability of the processing performance of PVB is guaranteed, and the rPVB particles are chemically bonded with an epoxy functionalized compatilizer in a specific ratio, and the three components are indispensable and cannot act together. Through triple synergistic effects of plasma activation, compatilizer chemical bonding and plasticizer regulation and control, a synergistic effect of '1 + 1 + 1gt, 3' is generated, the core problems of poor interface compatibility of rPET and rPVB and unstable performance of the recycled material are solved, and high-performance and high-value utilization of the total recycled material is realized. The composite non-woven material disclosed by the invention has excellent mechanical properties and dimensional stability, and the properties such as longitudinal tensile strength, interlayer peel strength and elongation at break of the composite non-woven material are balanced.

Description

Technical Field

[0001] This invention relates to the field of polymer material recycling and reuse technology, and in particular to a composite nonwoven material, its preparation method and application. Background Technology

[0002] The recycling and high-value utilization of plastics and composite materials have significant economic and social benefits. Among them, polyester (PET) from waste textiles and polyvinyl butyral (PVB) film from waste laminated glass have attracted widespread attention from technical personnel due to the limited avenues for high-value utilization.

[0003] Recycled PET (rPET) mainly comes from waste bottle flakes and textiles. Due to the thermal, mechanical, and potential hydrolysis processes during recycling and reprocessing, its molecular chains often break, leading to a decrease in intrinsic viscosity and a deterioration in mechanical properties. Therefore, rPET is currently mostly used in downgraded applications, such as in the production of low-value fibers, packing tape, or fillers, and cannot be directly used in nonwoven materials where high strength is required. Recycled PVB (rPVB) mainly comes from waste laminated glass in the automotive and construction industries. PVB films are separated from glass through crushing and sorting methods, but the resulting rPVB usually contains a certain amount of glass micropowder impurities, and its internal plasticizers (such as triethylene glycol diisooctanoate) may migrate or be lost, resulting in unstable and fluctuating adhesive and mechanical properties.

[0004] From a materials science perspective, PET is a crystalline polyester with relatively weak polarity, while PVB is an amorphous polymer containing hydroxyl groups, resulting in poor thermodynamic compatibility between the two. Simply blending rPET and rPVB leads to weak interfacial bonding, easily causing delamination and low strength in the composite material, severely restricting the technological path for preparing high-performance products from fully recycled materials. While there are reports of using virgin PVB as a binder to prepare composite materials, these rely on pure, stable virgin PVB resin, failing to address the core issue of compatibility when using recycled materials with complex compositions and varying properties.

[0005] In the prior art, Chinese patent CN113337920A discloses a core-sheath composite structure, and Chinese patent CN110922670A discloses a laminated fabric structure. However, they have failed to systematically solve the problems of weak interfacial bonding between rPET and rPVB due to thermodynamic incompatibility and material performance fluctuations caused by large performance fluctuations of recycled materials.

[0006] In summary, how to effectively improve the interfacial compatibility between rPET and rPVB, and how to prepare a stable composite nonwoven material using 100% recycled raw materials, are technical problems that urgently need to be solved in this field. Summary of the Invention

[0007] In view of this, the present invention provides a composite nonwoven material, its preparation method and application. The composite nonwoven material provided by the present invention effectively improves the interfacial compatibility between rPET and rPVB and has stable performance.

[0008] This invention provides a composite nonwoven material, comprising the following raw materials by weight: The mixture consists of 95-99 parts rPET fiber, 1-5 parts rPVB fiber, and 0.5-3 parts epoxy functionalized compatibilizer; the plasticizer content of the rPVB fiber is 10-15 wt%.

[0009] Preferably, the diameter of the rPET fiber is 10~30μm and the aspect ratio is 500~2000; the diameter of the rPVB fiber is 15~40μm and the aspect ratio is 300~1500.

[0010] Preferably, the intrinsic viscosity of the rPET fiber is 0.7~0.85 dL / g; the raw material of the rPVB fiber includes rPVB particles; the glass impurity content of the rPVB particles is less than 1.5 wt%, and the plasticizer content is 12~14 wt%.

[0011] Preferably, the epoxy functionalized compatibilizer includes an ethylene-methyl acrylate-glycidyl methacrylate (E-MA-GMA) terpolymer.

[0012] Preferably, the total mass fraction of the raw materials for the composite nonwoven material is 100 parts.

[0013] The present invention also provides a method for preparing the composite nonwoven material described above, comprising the following steps: (1) Plasma surface activation is performed on rPET fibers to obtain activated rPET fibers, wherein the surface energy of the activated rPET fibers is above 50 mN / m; (2) Plasticizer is adjusted on rPVB particles, and the plasticizer content is controlled at 10~15wt% to obtain pretreated rPVB particles. Then, the pretreated rPVB particles are melt-spun to obtain rPVB fibers. (3) The activated rPET fiber, rPVB fiber and epoxy functionalized compatibilizer are mixed and then sequentially carded and hot-pressed to obtain the composite nonwoven material; There is no requirement for the time order of steps (1) and (2).

[0014] Preferably, the plasma surface activation is low-temperature nitrogen plasma surface activation; the plasma surface activation temperature is room temperature (15~35 degrees Celsius), the power is 300~500W, the activation time is 2~5 minutes, and the cavity pressure is 50~200Pa.

[0015] Preferably, the carding equipment includes a carding machine; the carding cylinder speed is 800~1200 rpm, and the doffer speed is 30~60 rpm; the carding is performed using a cross-laying method; and the weight of the resulting fiber web is 50~150 g / m². 2 .

[0016] Preferably, the hot pressing process includes a preheating stage, a main bonding stage, and a shaping and cooling stage performed sequentially; the preheating stage has a temperature of 105~115℃, a pressure of 0.1~0.3MPa, and a time of 20~40 seconds; the main bonding stage has a temperature of 145~155℃, a pressure of 0.8~1.2MPa, and a time of 50~70 seconds; the shaping and cooling stage includes cooling and depressurization performed sequentially; the cooling is performed under pressure holding conditions; the pressure holding conditions are 0.8~1.2MPa; the cooling rate is 5~15℃ / min; and the final cooling temperature is below 50℃.

[0017] The present invention also provides the application of the composite nonwoven material described in the above-described scheme or the composite nonwoven material obtained by the preparation method described in the above-described scheme in the automotive, construction or packaging fields.

[0018] This invention provides a composite nonwoven material. The composite nonwoven material provided by this invention possesses excellent mechanical properties and dimensional stability (structural stability), with a longitudinal tensile strength of 70~88 N / cm, an interlaminar peel strength of 8~18 N / cm, and an elongation at break of 140~160%. The composite nonwoven material provided by this invention exhibits excellent and stable performance comparable to some virgin material products.

[0019] This invention also provides a method for preparing the composite nonwoven material described in the above-mentioned scheme. This invention uses fully recycled materials (100% recycled, rPET and rPVB) as raw materials. Plasma treatment provides an activated interface for the chemical reaction. Through plasticizer regulation, rPVB particles are processed into rPVB fibers, ensuring the stability of PVB processing performance. Then, it is chemically bonded with a specific ratio of epoxy functionalized compatibilizer. All three are indispensable and work together. This invention, through the triple synergistic effect of plasma activation, compatibilizer chemical bonding, and plasticizer regulation, produces a synergistic effect of "1+1+1>3," solving the core problems of poor interfacial compatibility between rPET and rPVB and unstable performance of recycled materials, achieving high-performance and high-value utilization of fully recycled materials. This invention is the first to systematically solve the key problems of preparing high-performance composite nonwoven materials using fully recycled materials, constructing a complete technical path from waste to high-value products, and possessing unique targeting and high efficiency for recycled material systems. The preparation method provided by this invention has strong controllability, good process stability, and good product quality consistency. It is suitable for large-scale production and has significant social and economic benefits.

[0020] Thanks to the robust interface formed by the aforementioned synergistic effect, the composite nonwoven material of this invention exhibits excellent and stable mechanical properties. The results of the embodiments show that the tensile strength and peel strength of the composite nonwoven material of this invention far exceed those of the comparative example, and its performance indicators reach or even exceed those of some ordinary nonwoven materials based on virgin materials such as polypropylene (PP) (e.g., Comparative Example 4). Simultaneously, by strengthening the interfacial bonding, this invention improves the elongation at break (140~160%) of the composite nonwoven material, achieving a balanced overall performance that makes it suitable for various application scenarios. It avoids abnormally high elongation caused by weak interfaces (e.g., the comparative example), achieving a good combination of high strength and moderate elongation.

[0021] This invention also provides applications of the composite nonwoven materials described in the above-described schemes or the composite nonwoven materials prepared by the above-described schemes in the automotive, construction, or packaging fields. The composite nonwoven materials provided by this invention exhibit excellent and stable mechanical properties, making them suitable for use in the automotive, construction, or packaging fields, such as automotive interiors, building insulation, and packaging liners. Detailed Implementation

[0022] This invention provides a composite nonwoven material, comprising the following raw materials by weight: The mixture consists of 95-99 parts rPET fiber, 1-5 parts rPVB fiber, and 0.5-3 parts epoxy functionalized compatibilizer; the plasticizer content of the rPVB fiber is 10-15 wt%.

[0023] The composite nonwoven material provided by the present invention comprises 95-99 parts by weight, preferably 96-98 parts by weight, and more preferably 97 parts by weight.

[0024] In this invention, the intrinsic viscosity of the rPET fiber is preferably 0.7~0.85 dL / g, more preferably 0.75~0.8 dL / g. By controlling the intrinsic viscosity of the rPET fiber within the above range, this invention ensures that the rPET fiber has a suitable molecular weight and processability, while providing a good mechanical property basis for composite nonwoven materials.

[0025] In this invention, the diameter of the rPET fiber is preferably 10-30 μm, more preferably 15-20 μm, and the aspect ratio is preferably 500-2000, more preferably 1000-1500.

[0026] Based on the mass fraction of the rPET fiber, the composite nonwoven material provided by the present invention includes 1 to 5 parts of rPVB fiber, preferably 2 to 4 parts, and more preferably 3 parts.

[0027] In this invention, the raw material for the rPVB fiber preferably includes rPVB particles; the glass impurity content of the rPVB particles is preferably less than 1.5 wt%, and the plasticizer content is preferably 12-14 wt%. Controlling the glass impurity content in this invention avoids its negative impact on processing equipment and product uniformity. This invention plays a crucial role in regulating the plasticizer content to the above-mentioned range, enabling the rPVB fiber to have suitable melt flowability and adhesive properties during hot pressing. If the plasticizer content is too low (<10%), the rPVB fiber will have high melt viscosity and poor flowability, making it difficult to fully wet the rPET fiber; if the plasticizer content is too high (>15%), the product will become sticky, have poor dimensional stability, and its mechanical properties will decrease.

[0028] In this invention, the diameter of the rPVB fiber is preferably 15-40 μm, more preferably 25-30 μm, and the aspect ratio is preferably 300-1500, more preferably 600-1200, and even more preferably 800-1000.

[0029] In this invention, the raw material for the composite nonwoven material is preferably a fully recycled material.

[0030] Based on the mass fraction of the rPET fiber, the composite nonwoven material provided by the present invention includes 0.5 to 3 parts of epoxy functionalized compatibilizer, preferably 1 to 2 parts, and more preferably 1.5 parts.

[0031] In this invention, the epoxy functionalized compatibilizer preferably comprises an ethylene-methyl acrylate-glycidyl methacrylate terpolymer; the repeating unit of the ethylene-methyl acrylate-glycidyl methacrylate terpolymer has the structural formula: [-(CH2-CH2)] x -(CH2-CH(COOCH3)) y -(CH2-C(CH3)(COOCH2-CH-CH2)) z The epoxy functionalized compatibilizer of the present invention has a main chain of ethylene units (denoted as E, -(CH2-CH2)). x -) and methyl acrylate unit (denoted as MA, -(CH2-CH(COOCH3)) y -) copolymer segment with glycidyl methacrylate units (denoted as GMA, -(CH2-C(CH3)(COOCH2-CH-CH2)) grafted onto the side chain. z -), where the ethylene unit provides the main chain flexibility and basic physical properties of the epoxy-functionalized compatibilizer; the methyl acrylate unit enhances the polarity of the epoxy-functionalized compatibilizer and improves its compatibility with polar polymers (such as rPET and rPVB); the glycidyl methacrylate unit has epoxy groups (glycidyl groups) on its side chain, which are reactive functional groups. Under hot pressing conditions, it can undergo ring-opening reactions with the terminal carboxyl / hydroxyl groups of rPET fibers and the hydroxyl groups of rPVB fibers to form chemical bonds, thereby significantly enhancing the interfacial bonding force between the two phases.

[0032] In this invention, the total mass fraction of the raw materials for the composite nonwoven material is preferably 100 parts.

[0033] The present invention also provides a method for preparing the composite nonwoven material described above, comprising the following steps: (1) Plasma surface activation is performed on rPET fibers to obtain activated rPET fibers, wherein the surface energy of the activated rPET fibers is above 50 mN / m; (2) Plasticizer is adjusted on rPVB particles, and the plasticizer content is controlled at 10~15wt% to obtain pretreated rPVB particles. Then, the pretreated rPVB particles are melt-spun to obtain rPVB fibers. (3) The activated rPET fiber, rPVB fiber and epoxy functionalized compatibilizer are mixed and then sequentially carded and hot-pressed to obtain the composite nonwoven material; There is no requirement for the time order of steps (1) and (2).

[0034] This invention involves plasma surface activation of rPET fibers to obtain activated rPET fibers with a surface energy of 50 mN / m or higher. The preferred method for preparing the rPET fibers includes the following steps: melt spinning recycled PET material; the melt spinning temperature is preferably 270-285°C, more preferably 275-280°C; the screw speed is preferably 30-50 rpm, more preferably 40 rpm; and the draw ratio is preferably 3-5, more preferably 4.

[0035] In this invention, the plasma surface activation is preferably low-temperature nitrogen plasma surface activation; the plasma surface activation temperature is preferably room temperature (15~35 degrees Celsius), the power is preferably 300~500W, more preferably 350~400W, the activation time is preferably 2~5 minutes, more preferably 3~4 minutes, and the chamber pressure is preferably 50~200Pa, more preferably 100~150Pa. This invention, through plasma surface activation, can introduce polar oxygen-containing groups such as carboxyl and hydroxyl groups onto the surface of rPET fibers and generate micro-etching to increase surface roughness, thereby greatly improving its surface energy (above 50 mN / m) and wettability to the compatibilizer melt, creating favorable conditions for subsequent interfacial chemical reactions.

[0036] This invention involves adjusting the plasticizer content of rPVB particles to 10-15 wt% to obtain pretreated rPVB particles, which are then melt-spun to obtain rPVB fibers.

[0037] In this invention, the particle size of the rPVB particles is preferably 2-4 mm, and more preferably 3 mm.

[0038] In this invention, the method for preparing the rPVB particles preferably includes the following steps: sequentially crushing, sorting, washing and granulating the recovered PVB material.

[0039] In this invention, the recycled PVB material is preferably recycled PVB film material.

[0040] In this invention, the target diameter of the broken pieces is preferably 5-10 mm, more preferably 6-9 mm, and even more preferably 7-8 mm.

[0041] In this invention, the sorting is preferably performed using wind-powered sorting or electrostatic sorting. This invention removes most glass impurities through sorting.

[0042] In this invention, the cleaning process preferably includes alternating water washing and solvent cleaning; the solvent used for solvent cleaning is preferably ethanol or isopropanol; the total number of cleaning cycles is preferably 2 to 3, and the cleaning time for each cycle is preferably 5 to 10 minutes. This invention removes surface deposits through cleaning.

[0043] In this invention, the granulation is preferably performed by extrusion granulation.

[0044] In this invention, the method for controlling plasticizers preferably includes one or both of Soxhlet extraction and supplementary addition.

[0045] In this invention, the Soxhlet extraction method preferably includes the following steps: placing 5g of rPVB particles in a Soxhlet extractor, using ethanol as a solvent, refluxing and extracting at 80°C for 6 hours, then removing and vacuum drying to constant weight, and calculating the plasticizer content.

[0046] In this invention, the vacuum drying temperature in the Soxhlet extraction method is preferably 60°C, and the vacuum degree is preferably -0.09 MPa.

[0047] In this invention, the supplementary addition method refers to adding plasticizer to rPVB particles that are deficient in plasticizer; the plasticizer preferably includes one or more of triethylene glycol diisooctanoate (3GO) and dioctyl sebacate (DOS).

[0048] In this invention, the supplementary addition method preferably includes the following steps: mixing the calculated amount of plasticizer with rPVB particles at high speed and then vacuum drying.

[0049] In this invention, the supplementary addition method preferably includes a high-speed mixer as the high-speed mixing equipment; the mixing speed is preferably 800-1200 rpm, the temperature is preferably room temperature, and the mixing time is preferably 10 minutes; the vacuum drying temperature is preferably 60°C, the vacuum degree is preferably -0.09 MPa, and the holding time is preferably 2 hours. This invention uses a high-speed mixer to ensure uniform adsorption of the plasticizer. Vacuum drying ensures thorough penetration of the plasticizer.

[0050] In this invention, the melt spinning temperature is preferably 160~180℃, more preferably 165~175℃, and even more preferably 170℃, and the screw speed is preferably 20~40rpm, more preferably 30rpm.

[0051] After obtaining activated rPET fibers and rPVB fibers, the present invention mixes the activated rPET fibers, rPVB fibers, and an epoxy functionalized compatibilizer (denoted as the first mixture), and then sequentially performs carding and hot pressing to obtain the composite nonwoven material. In the present invention, the epoxy functionalized compatibilizer is preferably added in powder form. Adding the epoxy functionalized compatibilizer in the above form facilitates its uniform dispersion in the fiber web formed by subsequent carding.

[0052] In this invention, the first mixing process preferably includes mechanically opening the activated rPET fibers and rPVB fibers.

[0053] In this invention, the carding equipment preferably includes a carding machine; the cylinder speed of the carding is preferably 800~1200 rpm, more preferably 900~1100 rpm, and the doffer speed is preferably 30~60 rpm, more preferably 40~50 rpm; the carding is preferably carried out by cross-laying; the basis weight of the fiber web obtained by carding is preferably 50~150 g / m². 2 More preferably 80~120g / m 2 .

[0054] In this invention, the equipment for hot pressing preferably includes a hot press; the hot pressing preferably includes a preheating stage, a main bonding stage, and a shaping and cooling stage performed sequentially; the temperature of the preheating stage is preferably 105~115℃, more preferably 110℃, the pressure is preferably 0.1~0.3MPa, more preferably 0.2MPa, and the time is preferably 20~40 seconds, more preferably 30 seconds.

[0055] In this invention, the temperature of the main bonding stage is preferably 145~155℃, more preferably 150℃, the pressure is preferably 0.8~1.2MPa, more preferably 1MPa, and the time is preferably 50~70 seconds, more preferably 60 seconds.

[0056] In this invention, the shaping and cooling stage preferably includes sequential cooling and depressurization; the cooling is preferably performed under pressure holding conditions; the pressure of the pressure holding conditions is preferably 0.8~1.2MPa, more preferably 1MPa; the cooling is preferably performed using cooling water to cool the mold; the cooling rate is preferably 5~15℃ / min, more preferably 10℃ / min; the final cooling temperature is preferably below 50℃.

[0057] The stepped hot-pressing process in this invention is key to controlling the composite process of incompatible systems. The preheating stage softens the rPVB fibers but doesn't completely melt them, facilitating uniform pressure transfer and initial compaction of the fiber web, while preventing direct high pressure from damaging the fiber web structure. During the main bonding stage, under the specified temperature and pressure, the rPVB fibers fully melt and flow, encapsulating the rPET fibers. Simultaneously, the epoxy functionalized compatibilizer melts, and its epoxy groups undergo a thorough interfacial chemical reaction with the activated rPET fiber surface and the hydroxyl groups of the rPVB fibers, forming a strong chemical bond and physical entanglement network, achieving a high-strength bond between the two phases. The rapid cooling during the shaping and cooling stage helps to "freeze" the formed good interfacial microstructure, preventing phase separation and improving the dimensional stability of the composite nonwoven material.

[0058] The present invention also provides the application of the composite nonwoven material described in the above-described scheme or the composite nonwoven material obtained by the preparation method described in the above-described scheme in the automotive, construction or packaging fields.

[0059] The composite nonwoven material provided by this invention has excellent mechanical properties and stable performance, making it suitable for use in the automotive, construction, or packaging fields, such as automotive interiors, building insulation, and packaging liners.

[0060] The core of the composite nonwoven material and its preparation method provided by this invention lies in establishing a strong bond at the interface between rPET fibers and rPVB fibers through the synergy of physical and chemical methods. The chemical principles, theories, and key chemical reactions involved are as follows: 1. Interfacial chemical reaction of epoxy functionalized compatibilizer: The epoxy groups (glycidyl esters) of the side chains of the E-MA-GMA terpolymer are activated in the main bonding stage of the step-by-step hot pressing molding process, and can undergo ring-opening reactions with the terminal functional groups of rPET fibers and the hydroxyl groups of rPVB fibers to form covalent bonds. The specific reaction is illustrated below: 1) Reaction with the terminal carboxyl groups (-COOH) of rPET fibers: ; X-CH2-CH-CH2 represents E-MA-GMA terpolymer, and HOOC-Y represents rPET fiber.

[0061] 2) Reaction with the terminal hydroxyl groups (-OH) of rPET fibers: ; X-CH2-CH-CH2 represents E-MA-GMA terpolymer, and HO-Y represents rPET fiber.

[0062] 3) Reaction with hydroxyl groups (-OH) on the rPVB fiber molecular chain: ; X-CH2-CH-CH2 represents E-MA-GMA terpolymer, and HO-Z represents rPVB fiber.

[0063] The aforementioned chemical reaction forms a chemical bridge between "epoxy functionalized compatibilizer-rPET fiber" and "epoxy functionalized compatibilizer-rPVB fiber" in the interfacial region, which greatly enhances the interfacial bonding force between the two originally incompatible phases.

[0064] 2. Mechanism of plasma surface activation: Plasma surface activation of rPET fibers, through high-energy particle bombardment and the interaction of active particles, mainly induces two effects on the rPET fiber surface: first, surface etching and cleaning: physical bombardment removes the weak boundary layer, increases surface roughness, and enhances mechanical interlocking ability; second, the introduction of chemical functional groups: under nitrogen and residual oxygen / water vapor environments, a large number of oxygen-containing polar groups, such as carboxyl groups (-COOH) and hydroxyl groups (-OH), are introduced onto the rPET fiber surface. The formation can be briefly represented as follows: rPET fiber surface + N2 / O / OH →rPET fiber surface -COOH / rPET fiber surface -OH; in Represents active species in plasma.

[0065] These newly introduced polar groups directly increase the surface energy of rPET fibers (above 50 mN / m) and provide more reaction sites for the aforementioned chemical reaction with epoxy functionalized compatibilizers.

[0066] 3. The calculation formulas for key performance parameters are as follows: 1) The formula for calculating the plasticizer content (wt%) by Soxhlet extraction is as follows: ; Where M1 is the mass of the sample before extraction, and M2 is the mass of the sample after extraction and drying to constant weight; 2) The formula for calculating the amount (by mass) of plasticizer added using the supplementary addition method is as follows: Target addition amount = (target plasticizer content - initial plasticizer content) × rPVB particle mass; 3) Calculation of glass impurity content (wt%): Glass impurity content = (mass of residue after ignition / mass of sample before ignition) × 100%.

[0067] The aforementioned chemical principles and theories, along with key chemical reactions and calculation formulas, together constitute the theoretical basis for this invention to achieve high-performance composites of fully recycled materials through the triple synergistic effect of "plasma activation - compatibilizer bonding - plasticizer regulation".

[0068] To further illustrate the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments thereof.

[0069] In the specific embodiments and comparative examples of the present invention, the test methods used are as follows: Intrinsic viscosity (IV): According to GB / T 14190-2017 "Test Methods for Fiber Grade Polyester Chips", the Ubbelohde viscometer was used, and the solvent was phenol / tetrachloroethane (weight ratio 1:1) at 25℃.

[0070] Glass impurity content: Weigh 5g of sample and place it in a pre-weighed crucible. Calculate the mass percentage by igniting the sample in a muffle furnace at 600℃ for 2 hours. After cooling, weigh the residue.

[0071] Soxhlet extraction for plasticizer content: Accurately weigh 5g of rPVB particles, reflux with ethanol solvent at 80℃ for 6 hours, and dry the extracted sample to constant weight in a vacuum oven at 60℃ and a vacuum degree of -0.09MPa. Calculate the percentage of mass loss.

[0072] Supplementing plasticizer content by addition: For rPVB particles with plasticizer content lower than the target range, mix the calculated mass of plasticizer (e.g., 3GO) with the rPVB particles at room temperature for 10 minutes in a high-speed mixer at 800~1200 rpm to ensure uniform adsorption, and then vacuum dry at 60℃ and -0.09MPa for 2 hours.

[0073] Surface energy: The contact angle of the composite nonwoven material surface is directly measured using a contact angle meter, and its surface energy is calculated to characterize the wettability of the composite nonwoven material surface.

[0074] Tensile strength and elongation at break: According to GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength and Elongation at Break (Strip Method)", the composite nonwoven material was cut into specimens with a width of 5 cm and a length of 20 cm. The test was conducted on a universal testing machine with a clamp spacing of 100 mm and a tensile speed of 100 mm / min. The strength results are reported in N / cm (5 cm specimen width), and the elongation at break is reported as a percentage.

[0075] Peel strength: According to GB / T 2791-1995 "Test method for peel strength of adhesives - flexible materials to flexible materials", the composite nonwoven material was cut into specimens with a width of 2.5 cm and a length of 15 cm. A 2 cm pre-peel was made at the end by hand to form a T-shaped peel. The peel test was carried out on a universal testing machine at a tensile speed of 100 mm / min. The results are expressed in N / cm.

[0076] Example 1: The raw materials used in this embodiment are as follows: rPET fiber: Derived from waste polyester textiles, produced through melt spinning at a temperature of 275℃, a screw speed of 40 rpm, a draw ratio of 4, a diameter distribution of 10~30μm, an aspect ratio distribution of 500~2000, and an IV of 0.78dL / g, meeting the industry standard for recycled polyester fibers. rPVB granules: Derived from waste automotive laminated glass, with an initial glass content of 2.0wt% and a plasticizer content of 18wt%.

[0077] Epoxy functionalized compatibilizer: E-MA-GMA terpolymer, conforming to compatibilizer industry standards.

[0078] The specific steps of the preparation method in this embodiment are as follows: (1) Preparation of rPVB particles: The recycled PVB membrane material is crushed into 5-10mm fragments using a crusher. Glass impurities are removed by wind separation. Surface adhering substances are removed by a combination of water washing and ethanol solvent cleaning. Each cleaning takes 8 minutes. After 3 cleanings, the fragments are extruded and granulated to obtain rPVB particles with a particle size of 2-4mm.

[0079] (2) Plasticizer control of rPVB particles: rPVB particles were refluxed with ethanol at 80℃ for Soxhlet extraction for 6 hours, and the plasticizer content was adjusted to 12wt%. After cleaning and drying, rPVB fibers were produced by melt spinning at 170℃, with a diameter distribution of 15~40μm and an aspect ratio distribution of 300~1500.

[0080] (3) Plasma surface activation of rPET fibers: rPET fibers were laid in a single layer on the electrode plate of a plasma treatment device (model: PT-1000S, Institute of Microelectronics, Chinese Academy of Sciences), nitrogen gas was introduced, the chamber pressure was controlled at 100 Pa, and the treatment was carried out for 3 minutes at a power of 400W. After plasma surface activation, the surface energy of the fibers increased from 42mN / m to 58mN / m.

[0081] (4) Fiber web preparation: Activated rPET fibers (97wt%), rPVB fibers (2wt%), and E-MA-GMA terpolymer powder (1wt%) were loosely mixed in a mixing chamber for 5 minutes, and then carded by a roller carding machine. The cylinder speed of the carding machine was 800~1200rpm, and the doffer speed was 30~60rpm. Through cross-laying, a web with a basis weight of 100 g / m² was obtained. 2 A uniform fiber web.

[0082] (5) Hot pressing: The fiber web is fed into a flat vulcanizing machine (model: XLB-D, Shanghai Rubber Machinery Factory). First, it is preheated at 110℃ and 0.2MPa for 30 seconds; then the temperature is rapidly increased to 150℃ and the pressure is increased to 1.0MPa, and held for 60 seconds; finally, while maintaining the pressure of 1.0MPa, 25℃ circulating cooling water is introduced to cool the mold and material to below 40℃, and then it is taken out to obtain the composite nonwoven material.

[0083] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 85 N / cm, the elongation at break is 152%, and the peel strength is 12 N / cm. The material has a dense structure and cannot be torn by hand. At the cross-section, the fibers are entangled and wrapped together, with no obvious delamination.

[0084] Example 2: The preparation method of this embodiment is the same as that of Example 1, except that the raw material ratio is adjusted to: 96wt% rPET fiber, 3wt% rPVB fiber and 1wt% epoxy functionalized compatibilizer; the IV of rPET fiber is 0.75dL / g, the plasticizer content of rPVB particles after plasticizer control is 13wt%; the power of plasma surface activation is 350W, the time is 4 minutes, and the surface energy after plasma surface activation is 56mN / m.

[0085] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 78 N / cm, the elongation at break is 148%, and the peel strength is 10 N / cm. The material exhibits excellent toughness.

[0086] Example 3: The preparation method in this embodiment is the same as in Example 1, except that the raw material ratio is adjusted as follows: 98wt% rPET fiber, 1.5wt% rPVB fiber, and 0.5wt% epoxy functionalized compatibilizer; the IV of rPET fiber is 0.82 dL / g, the glass content of rPVB particles is 1wt%, and the plasticizer content after plasticizer adjustment is 11wt%; the plasma surface activation power is 450W, the time is 2.5 minutes, and the surface energy after plasma surface activation is 60 mN / m. The temperature of the main bonding stage in hot pressing is 148℃, and the time is 65 seconds.

[0087] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 88 N / cm, the elongation at break is 155%, and the peel strength is 9 N / cm. The material has high rigidity.

[0088] Example 4: The preparation method of this embodiment is the same as that of Example 1, except that the raw material ratio is adjusted to: 95wt% rPET fiber, 4wt% rPVB fiber and 1wt% epoxy functionalized compatibilizer; the IV of rPET fiber is 0.70dL / g, and the plasticizer content of rPVB particles after plasticizer control is 15wt%; the power of plasma surface activation is 500W and the time is 5 minutes; the temperature of the main bonding stage in hot pressing is 155℃, the pressure is 1.2MPa and the time is 70 seconds, in order to accommodate higher rPVB fiber content.

[0089] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 72 N / cm, the elongation at break is 160%, and the peel strength is 13 N / cm. The material has good adhesion.

[0090] Example 5: The preparation method of this embodiment is the same as that of Example 1, except that the raw material ratio is adjusted as follows: 99wt% rPET fiber, 0.5wt% rPVB fiber and 0.5wt% epoxy functionalized compatibilizer; the IV of rPET fiber is 0.85dL / g, and the plasticizer content of rPVB particles after plasticizer control is 10wt%; the power of plasma surface activation is 300W and the time is 2 minutes; the temperature of the main bonding stage in hot pressing is 145℃, the pressure is 0.8MPa, and the time is 50 seconds.

[0091] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 82 N / cm, the elongation at break is 145%, and the peel strength is 8 N / cm. The material is closer to the style of pure PET nonwoven fabric, and is crisp.

[0092] Comparative Example 1: The preparation method of this comparative example is the same as that of Example 1, except that no epoxy functionalized compatibilizer is added and the rPET fiber is not plasma surface activated.

[0093] Performance test results: The longitudinal tensile strength of the composite nonwoven material is only 35 N / cm, the elongation at break is 180%, and the peel strength is 3 N / cm. The material is very easy to tear by hand along the interlayer, with a smooth and clear interface, showing obvious delamination.

[0094] Comparative Example 2: The preparation method of this comparative example is the same as that of Example 1, except that only 1 wt% of epoxy functionalized compatibilizer is added, and the rPET fiber is not plasma surface activated.

[0095] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 58 N / cm, the elongation at break is 170%, and the peel strength is 6 N / cm. These performances are superior to Comparative Example 1. However, the interface exhibits discontinuous failure during the peel test, indicating that the interfacial bonding is still not strong and the chemical bonds have not been effectively established.

[0096] Comparative Example 3: The preparation method of this comparative example is the same as that of Example 1, except that the rPVB particles are not controlled by plasticizers and the plasticizer content of the rPVB particles is 20%.

[0097] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 65 N / cm, the elongation at break is 190%, and the peel strength is 8 N / cm. The material surface has a noticeably sticky feel, there is overflow at the edges after hot pressing, the dimensional stability is poor, and slight curling occurs after 24 hours.

[0098] Comparative Example 4: This comparative example uses commercially available products with a weight of 100g / m³. 2 Polypropylene spunbond nonwoven fabric (commonly used for packaging liners).

[0099] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 55 N / cm, and the elongation at break is >200%. This material is a single component and has no interlayer delamination problem, but its overall strength is lower than that of Examples 1-5 of this invention.

[0100] Comparative Example 5 (Plasma treatment only, no compatibilizer): The preparation method of this comparative example is the same as that of Example 1, except that no epoxy functionalized compatibilizer is added, and rPET fiber (97wt%) and rPVB fiber (3wt%) are used.

[0101] Performance test results: The longitudinal tensile strength of the composite nonwoven material is 48 N / cm, the elongation at break is 175%, and the peel strength is 4 N / cm. This indicates that strong interfacial bonding cannot be achieved through physical modification alone.

[0102] The above examples and comparative data fully demonstrate that the core of this invention lies in the synergistic effect of "plasma surface activation," "compatibility agent chemical bonding," and "plasticizer regulation," none of which can be omitted. This synergistic effect, targeting the fully recycled material system and nonwoven material structure, differs fundamentally from Comparative Document 1 (core-sheath composite fiber) and Comparative Document 2 (laminated fabric) in material composition, product form, and key processes. This results in a fully recycled composite nonwoven material with high interfacial bonding strength, stable mechanical properties, and comparable performance to some virgin material products. The performance comparison of Examples 1-5 and Comparative Examples 1-5 is summarized in Table 1.

[0103] Table 1. Performance summary of Examples 1-5 and Comparative Examples 1-5:

[0104] As shown in Table 1, the composite nonwoven materials prepared in Examples 1-5 of this invention exhibit significantly better performance than Comparative Examples 1-5 in key indicators such as tensile strength and peel strength, while maintaining a suitable elongation at break. Comparative Examples 1-5, due to weak interfacial bonding, are prone to interfacial slippage and debonding under stress, resulting in higher elongation at break (170-190%), but this comes at the cost of sacrificing overall material strength and structural integrity. This invention, by strengthening interfacial bonding, achieves high strength while balancing the elongation at break to a level suitable for various application scenarios (150%), thus realizing a good combination of high strength and moderate elongation. This further demonstrates that: The synergistic effect of this invention is crucial: neither plasma treatment alone (Comparative Example 5) nor epoxy functionalized compatibilizer alone (Comparative Example 2) can achieve the superior effects of Examples 1-5 of this invention. Only through the synergy of all three can performance improvement and stability be achieved.

[0105] Superior performance: The composite nonwoven material prepared by this invention has a tensile strength that is significantly higher than that of Comparative Example 1 and also higher than that of common commercially available PP spunbond nonwoven fabrics. At the same time, the elongation at break is stable at around 150%, which proves its excellent comprehensive mechanical properties.

[0106] Wide applicability of formulation: In Examples 4 and 5, the rPVB content is 1-5%. With appropriate process fine-tuning, stable products that meet the usage requirements (tensile strength > 70 N / cm, peel strength > 8 N / cm, elongation at break 150%) can still be obtained, which proves the wide applicability and robustness of the present invention.

[0107] The composite nonwoven material prepared by this invention can be widely used in automotive interior parts (such as door panel liners, headliner substrates, and trunk mats), thermal and sound insulation materials in the construction industry, cushioning liners in the packaging industry, environmentally friendly filter materials, and various industrial wiping cloths, with broad market prospects.

[0108] The embodiments of the present invention have been described above; however, these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the above embodiments of the present invention without inventive effort are within the protection scope of the present invention.

Claims

1. A composite nonwoven material, characterized in that, By weight, it includes the following raw materials: 95-99 parts rPET fiber, 1-5 parts rPVB fiber and 0.5-3 parts epoxy functionalized compatibilizer; The plasticizer content of the rPVB fiber is 10~15wt%.

2. The composite nonwoven material according to claim 1, characterized in that, The rPET fiber has a diameter of 10~30μm and an aspect ratio of 500~2000; The rPVB fiber has a diameter of 15~40μm and an aspect ratio of 300~1500.

3. The composite nonwoven material according to claim 1, characterized in that, The intrinsic viscosity of the rPET fiber is 0.7~0.85 dL / g; The raw material for the rPVB fiber includes rPVB particles; The rPVB particles have a glass impurity content of less than 1.5 wt% and a plasticizer content of 12-14 wt%.

4. The composite nonwoven material according to claim 1, characterized in that, The epoxy functionalized compatibilizer includes an ethylene-methyl acrylate-glycidyl methacrylate terpolymer.

5. The composite nonwoven material according to claim 1, characterized in that, The total mass fraction of the raw materials for the composite nonwoven material is 100 parts.

6. A method for preparing the composite nonwoven material according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Plasma surface activation is performed on rPET fibers to obtain activated rPET fibers, wherein the surface energy of the activated rPET fibers is above 50 mN / m; (2) Plasticizer is adjusted on rPVB particles, and the plasticizer content is controlled at 10~15wt% to obtain pretreated rPVB particles. Then, the pretreated rPVB particles are melt-spun to obtain rPVB fibers. (3) The activated rPET fiber, rPVB fiber and epoxy functionalized compatibilizer are mixed and then sequentially carded and hot-pressed to obtain the composite nonwoven material; There is no requirement for the time order of steps (1) and (2).

7. The preparation method according to claim 6, characterized in that, The plasma surface activation is low-temperature nitrogen plasma surface activation; The plasma surface activation temperature is room temperature, the power is 300~500W, the activation time is 2~5 minutes, and the cavity pressure is 50~200Pa.

8. The preparation method according to claim 6, characterized in that, The equipment used for combing includes a combing machine; The cylinder rotation speed of the comb is 800~1200rpm, and the doffer rotation speed is 30~60rpm; The combing process employs a cross-network laying method; The weight of the fiber web obtained by the carding is 50~150 g / m². 2 .

9. The preparation method according to claim 6, characterized in that, The hot pressing process includes a preheating stage, a main bonding stage, and a shaping and cooling stage performed sequentially. The preheating stage has a temperature of 105~115℃, a pressure of 0.1~0.3MPa, and a time of 20~40 seconds. The temperature of the main bonding stage is 145~155℃, the pressure is 0.8~1.2MPa, and the time is 50~70 seconds; The shaping and cooling stage includes sequential cooling and depressurization; The cooling is performed under pressure holding conditions; The pressure under the pressure-holding condition is 0.8~1.2 MPa; The cooling rate is 5~15℃ / min; The final temperature of the cooling is below 50°C.

10. The application of the composite nonwoven material according to any one of claims 1 to 5 or the composite nonwoven material obtained by the preparation method according to any one of claims 6 to 9 in the automotive, construction or packaging fields.

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