A NONE PVC composite floor and its preparation method

Abstract

The present application relates to the field of floor manufacturing, and particularly relates to a NONE PVC composite floor and a preparation method thereof, the NONE PVC composite floor comprises a TPU surface layer, a substrate layer, a TPU balancing layer and a NONE PVC floor mat layer which are sequentially compounded from top to bottom; the TPU surface layer comprises a wear-resistant layer, a color film layer and a TPU middle layer in sequence; the TPU middle layer and the TPU balancing layer are the same in thickness and material; the substrate layer is formed by polypropylene and plant fiber particles through blending and extrusion. The NONE PVC composite floor in the present application completely eliminates the risk of releasing toxic substances in the processing and waste stages of traditional PVC floor, and creatively adopts a mirror-symmetrical structure with the same thickness and homogeneity of the core functional layer of the surface layer and the TPU balancing layer, successfully offsets the internal stress caused by temperature and humidity fluctuations, and suppresses the warping deformation of the floor to an almost unobservable level, significantly improves the paving flatness and long-term stability.

Description

Technical Field

[0001] This invention relates to the field of flooring manufacturing, and more particularly to a NONE PVC composite flooring and its preparation method. Background Technology

[0002] Polyvinyl chloride (PVC) in plastic flooring releases a variety of harmful gases during the processing and melting stage, and waste PVC products also release plasticizers and other substances during natural degradation, thus causing persistent pollution to the health of production workers and the surrounding environment.

[0003] While some progress has been made in exploring non-PVC alternatives for wood-plastic composite flooring, the inherent limitations of the material itself make it difficult to meet performance standards. Due to significant interfacial compatibility issues between plant fibers and the plastic matrix, this type of flooring is highly susceptible to dimensional instability in environments with varying temperature and humidity. This manifests as unacceptable expansion or contraction deformation, severely impacting the flatness and aesthetics after installation. Furthermore, the fragile interfacial bonding makes its surface significantly less resistant to damage, making it unable to withstand scratches and impacts from daily use, resulting in a drastically shortened lifespan.

[0004] Furthermore, structural design flaws in composite flooring have long plagued the industry. When the thermal expansion characteristics of different functional layers differ significantly, fluctuations in ambient temperature can cause severe warping and deformation of the boards, not only damaging the decorative effect but also potentially causing structural failure. To suppress deformation, the conventional approach is to increase the thickness of the substrate or introduce a reinforcing layer, but this significantly increases the product weight, raising costs throughout the entire process from transportation to installation. Meanwhile, the performance degradation of the underlayment layer, a crucial buffer structure, has long been overlooked. Common foamed materials undergo irreversible deformation after prolonged pressure, gradually losing their ability to level the floor. While some natural backing materials boast excellent environmental performance, they inherently suffer from susceptibility to moisture and mold, rapidly deteriorating in humid environments.

[0005] Faced with these challenges, the industry has attempted various technological approaches to seek breakthroughs. For example, while replacing PVC with polyester addressed environmental concerns, the material's insufficient low-temperature toughness led to a sharp deterioration in the product's impact resistance. Introducing elastomers to improve surface flexibility resulted in a significant decrease in the floor's load-bearing capacity due to a lack of effective support structure. These attempts demonstrate that simply replacing a single material cannot systematically resolve the multiple contradictions faced by composite flooring. Especially in key areas such as achieving long-term cushioning performance, overcoming structural stress imbalances, and eliminating production pollution sources, existing technologies have not yet provided truly effective solutions. How to overcome the inherent contradictions between environmental friendliness, stability, and durability through systematic innovation has become the core technological barrier facing the industry. Summary of the Invention

[0006] The present invention aims to overcome the significant threats to the environment and human health posed by PVC flooring in the prior art during manufacturing, use, and disposal. Furthermore, the exploration of alternative materials for NONE PVC cannot simultaneously address the inherent contradiction between stability and durability. Therefore, the present invention provides a NONE PVC composite flooring and its preparation method to overcome the aforementioned shortcomings.

[0007] To achieve the above-mentioned objectives, the present invention is implemented through the following technical solution:

[0008] Firstly, the present invention provides a PVC-free composite flooring.

[0009] It includes, from top to bottom, a TPU surface layer, a substrate layer, a TPU balancing layer, and a NONE PVC floor mat layer;

[0010] The TPU surface layer sequentially comprises a wear-resistant layer, a color film layer, and a TPU mid-layer; and...

[0011] The TPU middle layer and the TPU balance layer have the same thickness and material;

[0012] The substrate layer is formed by extrusion of polypropylene and plant fiber particles;

[0013] The NONE PVC floor mat layer contains a porous mesh structure.

[0014] As described in the background section, when phasing out PVC, the plastic flooring industry faced a dilemma for most alternatives: while using polyolefin substrates met environmental requirements, insufficient material rigidity led to a significant deterioration in the flooring's load-bearing capacity, resulting in frequent problems such as furniture indentations and localized collapses. More problematic was the inherent stress imbalance in the traditional three-layer "surface layer-substrate-backing" structure. Specifically, when the thermal deformation coefficients of the substrate and surface layers did not match, temperature fluctuations induced bidirectional bending deformation. However, conventional methods of thickening the substrate or adding metal reinforcement layers made the product bulky, negating the core advantage of lightweight plastic flooring. Therefore, this application finds that the root cause of the stress imbalance lies not only in the material itself but also in the disruption of structural symmetry and the lack of proper underlayment function.

[0015] Based on the above understanding, the research and development path of this application first focuses on the reconstruction of the material system. After abandoning PVC, thermoplastic polyurethane elastomer (TPU) was innovatively chosen for the surface layer. Its unique microphase separation structure of soft and hard segments provides both rubber-like resilience to resist impact indentation and the rigid support characteristics of plastic. However, a new problem was revealed in the single TPU surface layer test: the excessive shrinkage rate of the elastomer caused the edges of the board to curl. At this point, this application approached the issue from the essence of structural mechanics. Recognizing that the curling stemmed from the unequal shrinkage stress between the surface layer and the underlying layer, the concept of a "mirror-symmetric balance layer" was proposed: a TPU balance layer of the same thickness and homogeneity as the core functional layer (middle layer) of the TPU surface layer is added below the substrate layer, creating a mutually constraining tensile stress network between the upper and lower surfaces. This design, seemingly simple, requires precise material matching and thickness control: if the balance layer is too thin, it cannot offset the stress; if it is too thick, the board will become rigid; and differences in materials may cause interfacial delamination. Therefore, after dozens of comparative experiments, the principle of "equal thickness and homogeneity" was finally established, and the thermal deformation warpage was successfully suppressed to a level that is imperceptible to the naked eye.

[0016] Furthermore, while traditional foamed floor mats initially offer good cushioning, they undergo plastic deformation under sustained loads, gradually losing their leveling ability. Inspired by the resilient properties of fiber web structures in nonwoven materials, this application introduces a melt-spun fiber-web laying process into flooring manufacturing. By rapidly drawing polyester or polypropylene melt to form an interwoven fiber web, a three-dimensional porous structure with immediate elasticity and long-term creep resistance is applied to flooring. Additionally, this structure, together with the TPU balancing layer, forms a synergistic mechanism: the fiber web absorbs unevenness on the surface through microscopic deformation, while the balancing layer maintains the flatness of the board macroscopically. Together, they solve the challenge of adapting lightweight flooring to rough substrates.

[0017] The resulting four-layer composite structure (TPU surface layer / plant fiber reinforced substrate layer / TPU balancing layer / fiber mesh mat layer) effectively enhances overall performance: Firstly, in terms of environmental friendliness, it completely eliminates PVC and its derivative pollution, and all materials are recyclable; secondly, in terms of structural stability, the symmetrical stress design ensures minimal dimensional changes in the product under high temperature and humidity conditions, superior to conventional wood-plastic flooring; and thirdly, in terms of functional durability, the fatigue-resistant properties of the fiber mesh mat effectively improve the cushioning and leveling function, while the self-healing properties of the TPU surface layer significantly reduce the visibility of surface scratches. Furthermore, these advantages stem from a deep integration of material selection, structural design, and process innovation. For example, when polyurethane AB adhesive is used to bond the TPU surface layer and the substrate layer, the urethane groups in the TPU molecular chain can form hydrogen bonds with the hydroxyl groups of the plant fibers, thereby achieving interfacial strength exceeding physical anchoring; and the open structure of the fiber mesh mat promotes air circulation, objectively inhibiting mold growth.

[0018] Preferably, the wear-resistant layer contains an amorphous copolyester.

[0019] Preferably, the amorphous copolyester is PETG.

[0020] The wear-resistant layer in this application employs an innovative design using amorphous copolyester (particularly PETG), effectively overcoming the technical limitations of traditional flooring wear-resistant components. Compared to conventionally used alumina reinforced paper, PVC wear-resistant layers, or thermosetting resin layers, PETG, due to its amorphous molecular structure, forms a highly homogeneous continuous phase during curing, avoiding microcracks caused by localized stress concentration. This allows for the synergistic optimization of two key properties: its elongation at break (≥160%) imparts excellent impact toughness to the surface, effectively buffering the energy of heavy objects falling. In the examples, samples using PETG showed no visible damage under an 8N scratch test, fully verifying this advantage. More importantly, the difference in thermal expansion coefficients between PETG and the underlying TPU material is extremely low. Therefore, after hot pressing, a bonding interface dominated by molecular chain entanglement can be formed, fundamentally eliminating the risk of interlayer delamination during temperature fluctuations and significantly improving service life.

[0021] Preferably, the wear-resistant layer comprises, by weight percentage, 1-3% anti-sticking agent, 3-5% lubricant, 2-3% antistatic agent, and the balance being amorphous copolyester.

[0022] Preferably, the surface of the wear-resistant layer is further provided with a UV coating layer.

[0023] Preferably, the substrate layer comprises, by weight percentage, 30-70 wt% PP particles, 20-65 wt% plant fiber particles, 1-5 wt% coupling agent, and 0.5-5 wt% stabilizer.

[0024] The substrate layer in this application proposes an innovative combination of PP particles and plant fiber particles in a specific ratio. Its core value lies in the fact that 30-70 wt% of PP particles form a continuous phase framework, which, in conjunction with 20-65 wt% of plant fiber particles, constructs a unique interpenetrating network structure. This effectively mitigates the risk of interfacial delamination caused by the difference in thermal expansion between plastic and plant fiber, significantly improving dimensional stability. The addition of 1-5 wt% of coupling agent strengthens interfacial bonding, significantly enhancing the bonding strength between the two materials. Simultaneously, 0.5-5 wt% of stabilizer effectively inhibits the adverse effects of high-temperature degradation of plant fibers on processing. This synergistic system offers groundbreaking comprehensive benefits: significantly increasing strength while ensuring lightweight sheets, significantly improving moisture absorption deformation, and enabling the product to achieve excellent weather resistance and dimensional retention.

[0025] Preferably, the plant fiber particles are any one or more combinations of wood flour, pulp, and straw.

[0026] Preferably, the NONE PVC floor mat layer is composed of a porous mesh fiber layer with a porosity of 30-70%.

[0027] This porous mesh fiber layer, designed with a specific porosity range of 30-70%, overcomes the traditional challenge of balancing water absorption and permeability, structural strength, and long-term resilience in non-PVC floor mats. This highly controllable, three-dimensional network that permeates the entire material phase provides unique bidirectional flow channels, enabling efficient adsorption and diffusion of liquid moisture in a very short time, significantly reducing water retention time, while maintaining excellent internal skeletal support, effectively preventing the mechanical performance collapse caused by excessive porosity in similar materials. This results in several breakthrough advantages: significantly improved drying rate and moisture management capabilities, inhibiting mold and odor growth at the source; and high-tenacity mesh fiber support ensuring the product maintains high resilience and cushioning function even under frequent foot traffic and pressure without permanent deformation. Crucially, the controlled porosity provides a reliable structural guarantee for using environmentally friendly, biodegradable, or recycled fiber raw materials, enhancing the product's environmental friendliness throughout its entire lifecycle while ensuring functionality, achieving a deep integration of performance and sustainability.

[0028] Preferably, the material of the porous mesh fiber layer is selected from one or more of PET, PP, IXPE, cork, and EVA.

[0029] Secondly, the present invention also provides a method for preparing NONE PVC composite flooring, comprising the following steps:

[0030] (1) The wear-resistant layer, the color film layer and the TPU intermediate layer are composited into a TPU surface layer by hot pressing process;

[0031] (2) The TPU surface layer, the substrate layer and the TPU balancing layer are bonded together by an adhesive;

[0032] (3) Composite the NONE PVC floor mat layer containing a porous mesh structure to the back of the balance layer.

[0033] Preferably, step (1) includes laying the canvas, release film, TPU mid-layer, color film layer, wear-resistant layer, release film, embossed plate, release film, wear-resistant layer, color film layer, and TPU mid-layer in the press bearing tray in an arranged order, and then hot pressing it by the press.

[0034] Preferably, in step (1), the hot pressing temperature is 110-150℃, the hot pressing pressure is 3-7MPa, and the hot pressing time is 25-60min.

[0035] Preferably, after the hot pressing is completed, a cold pressing cooling and shaping step is also included. After the cold pressing is completed, a TPU surface layer containing a wear-resistant layer, a color film layer and a TPU intermediate layer is obtained.

[0036] The cold pressing temperature is 25-35℃, the cold pressing pressure is 7-13 MPa, and the cold pressing time is 30-40 min.

[0037] Preferably, step (1) is further completed by applying a UV coating layer to the surface of the wear-resistant layer and curing it.

[0038] Preferably, the process also includes the step of producing a NONE PVC floor mat layer with a porous mesh structure from a melt-spun polyester or polyolefin through a melt-spinning-drawing-web-laying process.

[0039] This application represents a groundbreaking breakthrough by directly transforming polymer melt into a monolithic fibrous network structure with three-dimensional interconnected pores, rather than relying on traditional foaming or bonding processes. This process precisely controls the stretching and stacking of the melt stream, naturally forming strong physical entanglements and micro-welded structures at the fiber interlacing points, thus solving key bottlenecks in existing technologies such as disordered pore distribution and weak interlayer bonding. This monolithically formed porous network exhibits superior structural integrity: its three-dimensional interconnected pores significantly improve the longitudinal penetration efficiency of liquids / gases, significantly accelerate moisture conduction, and prevent localized liquid accumulation; simultaneously, the elastic skeleton formed by the self-linking of fibers effectively disperses stress, allowing the material to quickly recover its original shape under frequent compression, significantly improving fatigue resistance and long-term stability. This continuous and efficient process eliminates the use of solvents and chemical foaming agents, not only significantly reducing production energy consumption and VOC emissions but also enabling the flexible and efficient processing of environmentally friendly raw materials such as plant-based polyesters or recycled polyolefins.

[0040] Therefore, this application has the following beneficial effects:

[0041] (1) Completely eliminate the risk of toxic substance release during the processing and disposal stages of traditional PVC flooring, and endow the product with green attributes throughout its entire life cycle;

[0042] (2) The innovative use of a mirror symmetric structure with the same thickness and material as the TPU balance layer and the core functional layer of the surface layer successfully offsets the internal stress caused by temperature and humidity fluctuations, suppresses the warping deformation of the board to an almost imperceptible level, and significantly improves the flatness and long-term stability of the paving.

[0043] (3) The fiber mesh structure flooring layer is introduced across the industry. Its unique three-dimensional porous network can efficiently absorb the unevenness of the ground through micro-elastic deformation. At the same time, it has anti-fatigue properties, which solves the industry problem of long-term pressure failure of traditional foam flooring and doubles the life of the buffering and leveling function.

[0044] (4) The interface between the TPU surface layer and the plant fiber substrate produces an unexpected synergy. The elastomer molecular chain and the cellulose hydroxyl group form a super strong hydrogen bond network, which greatly improves the interlayer peel strength, resulting in a qualitative leap in the impact resistance of the product and effectively resisting the heavy pressure of furniture and daily scratches. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0046] The preparation methods of the wear-resistant layer, color film layer, TPU intermediate layer, substrate layer, TPU balancing layer, and NONE PVC floor mat layer in this application embodiment are as follows:

[0047] Preparation of the wear-resistant layer

[0048] Wear-resistant layer 1: Weigh the raw materials by weight percentage: 92% PETG granules, 1% anti-sticking agent, 5% lubricant, and 2% antistatic agent. Mix the above raw materials first through an extruder, then fully plasticize them through a screw, extrude them through a die, cool and shape them through a cooling roller, cut them into appropriate sizes, and place them on a tray for later use, to obtain wear-resistant layer 1 with a thickness of 0.1-1.0 mm.

[0049] Wear-resistant layer 2: Weigh the raw materials by weight percentage: 91% PETG granules, 3% anti-sticking agent, 3% lubricant, and 3% antistatic agent. Mix the above raw materials first through an extruder, then fully plasticize them through a screw, extrude them through a die, cool and shape them through a cooling roller, cut them into appropriate sizes, and place them on a tray for later use, resulting in a wear-resistant layer 2 with a thickness of 0.1-1.0 mm.

[0050] [Preparation of the color filter layer]

[0051] The color film layer is a PETG printed color film with a thickness of 0.05-0.10mm.

[0052] [Preparation of TPU Middle Layer]

[0053] According to the weight proportions, 50 parts of fully dried TPU, 150 parts of calcium powder, 3 parts of lubricant (bio-based polyester), 0.1 parts of antioxidant, 4 parts of stabilizer (PM), 0.1 parts of flame retardant, and 0.1 parts of blender are mixed in the following proportions. The mixture is first mixed in an extruder, then fully plasticized by a screw, and then extruded through a die. After being cooled and shaped by a cooling roller, it is cut into appropriate sizes and placed on a tray for later use. The screw speed is between 20-60 rpm, and the die temperature is controlled between 170-230℃.

[0054] [Preparation of the substrate layer]

[0055] Substrate Layer 1: Raw materials are weighed by weight percentage as follows: 30wt% PP granules, 65wt% plant fiber granules (100-mesh wood flour), 3wt% coupling agent, and 2wt% stabilizer. These raw materials are then poured into a high-speed mixer for mixing. After mixing, the material is poured into a feeding hopper. Under the shearing, dispersing, and extrusion action of a conical twin-screw extruder, the material is plasticized and extruded. The temperatures are shown in Table 1. The extruded material is cooled, pulverized, and then extruded through a rectangular grinding nozzle using a single-screw extruder. The temperatures are shown in Table 2. After cooling and cutting by cooling rollers, the surface is sanded and then placed on a tray for later use.

[0056] Substrate Layer 2: Raw materials are weighed according to the following weight percentages: 70wt% PP granules, 20wt% plant fiber granules (100-mesh straw powder), 5wt% coupling agent, and 5wt% stabilizer. These raw materials are then poured into a high-speed mixer for mixing. After mixing, the material is poured into a feeding hopper. Under the shearing, dispersing, and extrusion action of the conical twin-screw extruder, the material is plasticized and extruded. The temperatures are shown in Table 1. The extruded material is cooled and pulverized, then extruded through a single-screw extruder via a rectangular grinding nozzle. The temperatures are shown in Table 2. After cooling and cutting by cooling rollers, the surface is sanded and placed on a tray for later use.

[0057] Substrate Layer 3: Raw materials are weighed according to the following weight percentages: 40wt% PP granules, 58.5wt% plant fiber granules (100-mesh pulp powder), 1wt% coupling agent, and 0.5wt% stabilizer. The above raw materials are then poured into a high-speed mixer for mixing. After mixing, the material is poured into a feeding hopper. Under the shearing, dispersing, and extrusion action of the conical twin-screw extruder, the material is plasticized and extruded. The temperatures are shown in Table 1. The extruded material is cooled and pulverized, then extruded through a single-screw extruder via a rectangular grinding nozzle. The temperatures are shown in Table 2. After cooling and cutting by cooling rollers, the surface is sanded and placed on a tray for later use.

[0058] Table 1. Temperature of Twin-Screw Extruder

[0059] Equipment area Set temperature (°C) Zone 1 170 Zone 2 165 Zone 3 150 4th District 155 5th District 160 District 6 160 machine head 160

[0060] Table 2 Single-screw extruder temperature

[0061] Equipment area Set temperature (°C) Feeding section 155 compression section 165 Melting section 175

[0062]

Preparation of NONE PVC Floor Mat Layer

[0063] NONE PVC floor mat layer 1: 90 parts PET resin, 4 parts compatibilizer, 3 parts flame retardant, 1 part lubricant, 1 part antioxidant, and 1 part flame retardant are mixed and melted into a polyester melt. The melt is filtered to remove impurities and pumped into a spinneret to form a fine stream of melt, or sprayed out through nozzles. After being drawn at high speed by a drawer, the crystallinity of the monofilaments is improved. Then, it is evenly laid on a mesh curtain by a slab to form a fiber web. After reaching a thickness of 0.5-2.0mm, it is sent to a reinforcement device for reinforcement. Then, it is heated and pressed to form patterns, cut edges and shaped, and then wound to form a floor mat.

[0064] NONE PVC floor mat layer 2: Mix 90 parts PP resin, 5 parts compatibilizer, 3 parts flame retardant, 1 part lubricant, 1 part antioxidant, and 1 part flame retardant and melt them into a polyester melt. The melt is filtered to remove impurities and pumped into a spinneret to form a fine stream of melt, or sprayed out through nozzles. After being drawn at high speed by a drawer, the crystallinity of the monofilaments is improved. Then, it is evenly laid on a netting curtain by a slab to form a fiber web. After reaching a thickness of 0.5-2.0mm, it is sent to a reinforcement device for reinforcement. Then, it is heated and pressed to form patterns, cut edges and shaped, and then wound to form a floor mat.

[0065] Example 1

[0066] A method for preparing NONEPVC composite flooring includes the following steps:

[0067] (1) The canvas, release film, TPU medium layer, color film layer, wear-resistant layer 1, release film, embossed plate, release film, wear-resistant layer 1, color film layer, and TPU medium layer are laid in the press bearing tray in the order of arrangement. The canvas is used to reduce the cushioning, the release film is used to facilitate demolding, and the embossed plate is used to press the appropriate pattern on the surface according to the requirements. The hot pressing temperature is 115℃, the hot pressing pressure is 7MPa, and the hot pressing time is 60min. After the hot pressing is completed, the cold pressing is switched to cooling and shaping. The cold pressing temperature is 35℃, the cold pressing pressure is 7MPa, and the cold pressing time is 30min. After the cold pressing is completed, the product is removed and neatly placed on the tray to obtain the TPU surface layer semi-finished product.

[0068] (2) The surface of the TPU surface layer semi-finished product obtained in step (1) is subjected to UV coating treatment, that is, a UV coating layer is applied to the surface by roller coating, with a coating amount of 15g / m 2 During this process, the material is cured by UV light and then tempered by hot and cold water to obtain the TPU surface layer.

[0069] (4) Apply adhesive evenly to the surface of substrate layer 1 using an adhesive applicator. After adhesive application, laminate the TPU surface layer onto the substrate surface using a single-sided pressure roller. Flip the substrate layer 1 over and apply TPU intermediate material as a balancing layer to the back of substrate layer 1 using a single-sided pressure roller. The adhesive is a hot melt adhesive or water-based polyurethane adhesive, and the amount of adhesive is 80g / m². 2 After lamination, the product is pressed using a cold press for 12 hours at a pressure of 10 MPa.

[0070] (4) The semi-finished product with both sides glued together in step (4) is cut into pieces by grooving through the grooving line;

[0071] (5) The semi-finished product from step (4) is laminated with NONE PVC floor mat layer 1 and the other side of the balance layer using glue through a laminating machine. The glue is hot melt adhesive or water-based polyurethane adhesive.

[0072] Example 2

[0073] A method for preparing PVC-free composite flooring includes the following steps:

[0074] (1) The canvas, release film, TPU mid-layer, color film layer, wear-resistant layer 2, release film, embossed plate, release film, wear-resistant layer 2, color film layer, and TPU mid-layer are laid in the press bearing tray in the order of arrangement. The canvas is used to reduce the cushioning, the release film is used to facilitate demolding, and the embossed plate is used to press the appropriate pattern on the surface according to the requirements. The hot pressing temperature is 150℃, the hot pressing pressure is 3MPa, and the hot pressing time is 25min. After the hot pressing is completed, the cold pressing is switched to cooling and shaping. The cold pressing temperature is 25℃, the cold pressing pressure is 13MPa, and the cold pressing time is 40min. After the cold pressing is completed, the product is removed and neatly placed on the tray to obtain the TPU surface layer semi-finished product.

[0075] (2) The surface of the TPU surface layer semi-finished product obtained in step (1) is subjected to UV coating treatment, that is, a UV coating layer is applied to the surface by roller coating, with a coating amount of 22g / m 2 During this process, the material is cured by UV light and then tempered by hot and cold water to obtain the TPU surface layer.

[0076] (4) Apply adhesive evenly to the surface of substrate layer 2 using an adhesive applicator. After adhesive application, laminate the TPU surface layer onto the surface of substrate layer 2 using a single-sided pressure roller. Flip substrate layer 2 over and apply TPU intermediate material to the back of substrate layer 2 as a balancing layer using a single-sided pressure roller. The adhesive is a hot melt adhesive or water-based polyurethane adhesive, and the amount of adhesive is 120g / m². 2 After lamination, the material is pressed using a cold press for 12 hours at a pressure of 15 MPa.

[0077] (4) The semi-finished product with both sides glued together in step (4) is cut into pieces by grooving through the grooving line;

[0078] (5) The semi-finished product from step (4) is laminated with NONE PVC floor mat layer 1 and the other side of the balance layer using glue through a laminating machine. The glue is hot melt adhesive or water-based polyurethane adhesive.

[0079] Example 3

[0080] A method for preparing PVC-free composite flooring includes the following steps:

[0081] (1) The canvas, release film, TPU medium layer, color film layer, wear-resistant layer 2, release film, embossed plate, release film, wear-resistant layer 2, color film layer, and TPU medium layer are laid in the press bearing tray in the order of arrangement. The canvas is used to reduce the cushioning, the release film is used to facilitate demolding, and the embossed plate is used to press the appropriate pattern on the surface according to the requirements. The hot pressing temperature is 125℃, the hot pressing pressure is 5MPa, and the hot pressing time is 40min. After the hot pressing is completed, the cold pressing is switched to cooling and shaping. The cold pressing temperature is 30℃, the cold pressing pressure is 10MPa, and the cold pressing time is 35min. After the cold pressing is completed, the product is removed and neatly placed on the tray to obtain the TPU surface layer semi-finished product.

[0082] (2) The surface of the TPU surface layer semi-finished product obtained in step (1) is subjected to UV coating treatment, that is, a UV coating layer is applied to the surface by roller coating, with a coating amount of 22g / m 2 During this process, the material is cured by UV light and then tempered by hot and cold water to obtain the TPU surface layer.

[0083] (4) Apply adhesive evenly to the surface of substrate layer 3 using an adhesive applicator. After application, laminate the TPU surface layer onto the surface of substrate layer 3 using a single-sided roller bonding method. Flip substrate layer 3 over and apply TPU intermediate material to the back of substrate layer 3 as a balancing layer using a single-sided roller bonding method. The adhesive is hot melt adhesive or water-based polyurethane adhesive, and the amount of adhesive is 80g / m². 2 After lamination, the material is pressed using a cold press for 12 hours at a pressure of 15 MPa.

[0084] (4) The semi-finished product with both sides glued together in step (3) is cut into pieces by grooving through the grooving line;

[0085] (5) The semi-finished product from step (4) is laminated with NONE PVC floor mat layer 2 and the other side of the balance layer using glue through a laminating machine. The glue is hot melt adhesive or water-based polyurethane adhesive.

[0086] Comparative Example 1

[0087] Comparative Example 1 is a conventional WPC flooring containing PVC, whose structure consists of: 0.5mm wear-resistant material + colored film + 1.1mm base material + 4.8mm WPC substrate + 1.0mm MmixPE.

[0088] The base material contains 50 parts PVC, 17.8 parts DOTP, 219.5 parts calcium powder, and 0.8 parts stabilizer.

[0089] Comparative Example 2

[0090] The difference between Comparative Example 2 and Example 1 is that the balancing layer in the structure was removed.

[0091] Comparative Example 3

[0092] The difference between Comparative Example 3 and Example 1 is that the ratio of the thickness of the TPU material layer to the thickness of the TPU balance layer is 0.8:1.

[0093] Comparative Example 4

[0094] The difference between Comparative Example 4 and Example 1 is that the plant fiber particles in the substrate layer were replaced with an equal mass of stone powder.

[0095] Comparative Example 5

[0096] The difference between Comparative Example 5 and Example 1 is that the NONE PVC floor mat layer was replaced with IXPE foam material of equal thickness.

[0097] The composite flooring prepared in Examples 1-3 and Comparative Examples 1-5 was tested. The test methods and test results are shown in Table 3 below.

[0098] Table 3

[0099] Test Name Cold dimensional stability and curl testing at -18°C Thermal dimensional stability and curling at 70 degrees Thermal dimensional stability and curling at 80 degrees Scratch resistance wheelchair test Residual depression standard ISO23999-2021 ISO23999-2021 ISO23999-2021 EN 438-2 ISO 4918 ASTM F1914-2018 Example 1 L:0.002%; W: 0.011%; C:0.1 mm L:-0.007%; W:0.022%; C:0.125 mm L:-0.008%; W:0.022%; C:0.88mm 8N 30000R, pass 0.01mm Example 2 L:-0.023%; W: 0.044%; C:0.225mm L:0.02%; W: 0.033%; C:0.388 mm L:-0.02%; W:0.033%; C:0.575mm 8N 30000R, pass 0.02mm Example 3 L:-0.01%; W: 0.022%; C:0.188 mm L:-0.01%; W:0.022%; C:0.225 mm L:-0.02%; W:0.022%; C:0.338 mm 8N 30000R, pass 0.01mm Comparative Example 1 L: -0.033%; W: -0.022%; C: 0.20 mm L:0.059%; W:0.044%; C:0.938 mm L:0.074%; W:0.049%; C:1.05 mm 5N 25000R, pass 0.06mm Comparative Example 2 L:0.033%; W: 0.022%; C:0.388mm L:-0.01%; W:0.033%; C:0.688 mm L:-0.01%; W:0.033%; C:1.038 mm 8N 30000R, pass 0.03mm Comparative Example 3 L:0.013%; W: 0.022%; C:0.16 3mm L:-0.01%; W:0.027%; C:0.513mm L:-0.008%; W:0.027%; C:0.725 mm 8N 30000R, pass / Comparative Example 4 L:0.044%; W: 0.044%; C:0.263mm L:-0.028%; W:0.022%; C:0.425mm L:-0.02%; W:0.011%; C:0.975 mm 8N 30000R, pass / Comparative Example 5 L:0.023%; W:0.022%; C:0.125 mm L:-0.002%; W:0.027%; C:0.263mm L:-0.01%; W:0.033%; C:0.338 mm 8N 25000R, pass 0.05mm

[0100] [Performance Analysis]

[0101] As shown in the table above, the NONE PVC composite flooring prepared in this application exhibits significantly improved dimensional stability under both hot and cold conditions compared to existing WPC flooring containing PVC. Furthermore, comparing Example 1 with Comparative Example 1 reveals that eliminating the balancing layer in the NONE PVC composite flooring significantly reduces its dimensional stability under hot and cold conditions. The thickness ratio between the balancing layer and the TPU middle layer also influences dimensional stability to some extent. Therefore, the presence and thickness of the balancing layer have a significant impact on the dimensional stability of the PVC-free composite flooring. Comparing Example 1 with Comparative Example 4 shows that replacing the fibers in the substrate layer with an equal mass of stone powder also significantly reduces dimensional stability, indicating that the cellulose in the substrate layer can build a special interpenetrating network structure within the substrate, effectively mitigating the risk of interfacial delamination caused by the difference in thermal expansion between plastic and plant fibers, thus significantly improving dimensional stability. Furthermore, by comparing Comparative Examples 1 and 5 with the embodiments, we can see that after replacing the NONE PVC floor mat layer in this application with IXPE material, the results of the wheelchair test and residual indentation test decreased. This indicates that the three-dimensional porous structure inside the scheme of interlacing fibers into a fiber web in this application can have both immediate elasticity and long-term creep resistance. Moreover, this structure forms a synergistic mechanism with the TPU balancing layer, thereby absorbing the unevenness of the ground through micro-deformation.

[0102] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A NONE PVC composite floor, characterized in that, it comprises a TPU surface layer, a substrate layer, a TPU balancing layer and a NONE PVC floor mat layer which are sequentially compounded from top to bottom; the TPU surface layer comprises a wear-resistant layer, a color film layer and a TPU middle layer in sequence; and, the TPU middle layer and the TPU balancing layer are the same in thickness and material; the substrate layer is formed by extrusion of polypropylene and plant fiber particles; the NONE PVC floor mat layer comprises a porous network structure.

2. The NONE PVC composite floor according to claim 1, characterized in that, the wear-resistant layer comprises an amorphous copolyester.

3. The NONE PVC composite floor according to claim 2, characterized in that, the wear-resistant layer comprises 1-3% of anti-adhesive agent, 3-5% of lubricant, 2-3% of antistatic agent and the rest of amorphous copolyester by weight percentage.

4. The NONE PVC composite floor according to claim 1 or 2 or 3, characterized in that, the surface of the wear-resistant layer is further provided with a layer of UV paint.

5. The NONE PVC composite floor according to claim 1, characterized in that, the substrate layer comprises PP particles 30-70wt%, plant fiber particles 20-65wt%, coupling agent 1-5wt% and stabilizer 0.5-5wt% by weight percentage.

6. The NONE PVC composite floor according to claim 1 or 5, characterized in that, the plant fiber particles are any one or a combination of wood powder, pulp and straw.

7. The NONE PVC composite floor according to claim 1, characterized in that, the NONE PVC floor mat layer is composed of a porous network fiber layer, and the porosity of the porous network fiber layer is 30-70%.

8. The NONE PVC composite floor according to claim 7, characterized in that, the material of the porous network fiber layer is selected from one or more of PET, PP, IXPE, softwood and EVA.

9. A method of manufacturing the NONE PVC composite floor panel according to any one of claims 1-8, characterized in that, comprising the following steps: (1) Compounding the wear-resistant layer, the color film layer and the TPU middle layer into the TPU surface layer by hot pressing process; (2) Compounding the TPU surface layer, the substrate layer and the TPU balancing layer by adhesive; (3) Compounding the NONE PVC floor mat layer comprising a porous network structure to the back of the balancing layer.

10. The method according to claim 9, characterized in that, the step (1) comprises the steps of laying canvas, release film, TPU middle layer, color film layer, wear-resistant layer, release film, embossing plate, release film, wear-resistant layer, color film layer, TPU middle layer in the pressing machine bearing tray according to the arrangement order, and then hot pressing by the pressing machine, wherein the canvas functions as shock absorption, the release film functions as easy demolding, and the embossing plate functions as pressing appropriate patterns on the surface according to requirements.

11. The method according to claim 9 or 10, characterized in that, The hot pressing temperature in step (1) is 115-150℃, the hot pressing pressure is 3-7MPa, and the hot pressing time is 25-60min.

12. The method of claim 10, wherein, After the hot pressing, a cold pressing temperature setting step is further included, and after the cold pressing, a TPU surface layer containing the wear-resistant layer, the color film layer, and the TPU middle layer is obtained. The cold pressing temperature is 25-35℃, the cold pressing pressure is 7-13 MPa, and the cold pressing time is 30-40min.

13. The method of claim 9 or 10 or 12, wherein, After step (1) is completed, a step of coating a UV coating layer on the surface of the wear-resistant layer and curing is further included.

14. The method of claim 9, wherein, A step of preparing a NONE PVC ground mat layer containing a porous network structure through a melt spinning-drawing-laying process of a polyester or polyolefin melt is further included.