Degradable stone plastic floor and preparation method thereof

Abstract

This invention discloses a biodegradable stone-plastic flooring and its preparation method, relating to the field of layered stone-plastic flooring technology. A biodegradable stone-plastic flooring comprises, from bottom to top: a substrate layer, a decorative layer, and an anti-UV aging layer; the anti-UV aging layer is prepared from an anti-UV aging material; the anti-UV aging material, by weight, comprises: 80-90 parts polylactic acid, 25-30 parts polybutylene terephthalate, 30 parts polyvinyl chloride, 3-5 parts silica, 0.5-2 parts UV absorber, 3-8 parts epoxidized soybean oil, and 1-3 parts processing aids. By introducing a specially formulated UV absorber and a multi-level protection mechanism (including UV conversion, scattering, and chemical stabilization), this invention effectively inhibits the destructive effects of UV radiation on the flooring, thereby significantly reducing surface discoloration, cracking, and powdering, and improving the overall weather resistance of the material.

Description

Technical Field

[0001] This invention relates to the field of layered stone-plastic flooring technology, specifically to a biodegradable stone-plastic flooring and its preparation method. Background Technology

[0002] Traditional stone-plastic flooring commonly faces severe weather resistance issues when used outdoors or in environments with strong sunlight for extended periods. Ultraviolet radiation (especially UV-A and UV-B bands) triggers deep photochemical degradation of the material, leading to surface discoloration, chalking, and cracking. The core mechanism of this phenomenon lies in the photo-oxidation reaction of polymer molecular chains under ultraviolet light, causing chain breakage and cross-linking failure. Common components such as polyvinyl chloride (PVC) are particularly sensitive to ultraviolet light; the C-Cl bonds in their molecules are easily photoexcited and broken, generating free radicals and triggering chain reactions, accelerating the decline of the material's mechanical properties. Furthermore, ultraviolet light also damages the structural stability of organic pigments, causing the wood or stone grain patterns in the decorative layer to fade and become distorted, severely affecting aesthetics.

[0003] While existing technologies attempt to mitigate aging by adding general-purpose UV absorbers (such as benzotriazole derivatives), the effects are limited. These additives often suffer from poor thermal stability and high migration loss rates, and are prone to photodegradation failure after long-term exposure, failing to provide durable protection. Furthermore, a single protection mechanism is insufficient to cope with complex environmental stresses: after UV rays penetrate the surface layer, they further attack the substrate layer, causing internal microcracks and dimensional deformation.

[0004] More seriously, traditional flooring materials struggle to balance weather resistance and environmental sustainability. Petrochemical-based polymers (such as PVC) degrade slowly in the natural environment, creating white pollution upon disposal; while some biodegradable materials (such as PLA) fail to meet outdoor usage requirements due to insufficient heat resistance and UV resistance. This contradiction has led the industry to a long-standing dilemma: improving short-term weather resistance relies on non-biodegradable stabilizers, which exacerbates the environmental burden; pursuing biodegradability sacrifices product lifespan, increasing replacement frequency and economic costs. The market urgently needs an innovative solution that achieves a balance between maintaining aesthetics and mechanical strength, and simultaneously providing multi-level UV protection (synergistic absorption, scattering, and quenching) and biodegradability. Summary of the Invention

[0005] This invention aims to solve the problems of insufficient UV aging resistance and non-degradability of existing stone plastic flooring, and provides a stone plastic flooring with a clear layered structure and strong anti-aging properties, as well as its preparation process, so as to extend the service life of the flooring, improve the quality of use and reduce environmental pollution.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a biodegradable stone-plastic flooring, comprising, from bottom to top: a substrate layer, a decorative layer, and an anti-ultraviolet aging layer;

[0007] The UV aging resistant layer is made of UV aging resistant material;

[0008] The anti-UV aging material comprises, by weight, 80-90 parts of polylactic acid, 25-30 parts of polybutylene terephthalate, 30 parts of polyvinyl chloride, 3-5 parts of silicon dioxide, 0.5-2 parts of UV absorber, 3-8 parts of epoxidized soybean oil, and 1-3 parts of processing aid.

[0009] The ultraviolet absorber is a compound represented by Formula 1:

[0010]

[0011] In Formula 1, R1 is hydrogen, methyl, hydroxyl, or methoxy.

[0012] Furthermore, the epoxidized soybean oil has an epoxy value of 6.2-6.8%, an acid value of ≤0.5mg KOH / g, and an iodine value of ≤6gI2100g.

[0013] Furthermore, the processing aid is processing aid ACR.

[0014] Furthermore, the ultraviolet absorber is any one of the compounds shown in the following structures:

[0015]

[0016] Furthermore, the substrate layer is composed of a biodegradable polylactic acid material;

[0017] The biodegradable polylactic acid material comprises the following raw materials in parts by weight: 80-95 parts polylactic acid, 5-10 parts triethyl citrate, 2-8 parts talc, 1-3 parts processing aid ACR, and 1-3 parts stearic acid.

[0018] Furthermore, the decorative layer is made of a PVC film printed with wood grain or stone grain, with a thickness of 0.1-0.5mm.

[0019] A method for preparing biodegradable stone-plastic flooring includes the following steps:

[0020] (1) Preparation of substrate layer: The polylactic acid, triethyl citrate, talc, processing aid ACR and stearic acid are mixed and melt-extruded at 160-180℃ to form a sheet substrate layer;

[0021] (2) Preparation of decorative layer: Provide a PVC film with a thickness of 0.1-0.5mm, print wood grain or stone grain patterns to form a decorative layer;

[0022] (3) Preparation of anti-ultraviolet aging layer: The polylactic acid, polybutylene terephthalate, polyvinyl chloride, silicon dioxide, ultraviolet absorber, epoxidized soybean oil and processing aid are mixed, melt-blended at 170-190℃, and extruded into a film to obtain the anti-ultraviolet aging layer;

[0023] (4) Lamination: The substrate layer, decorative layer and anti-UV aging layer are stacked in sequence and laminated in a hot press at a pressure of 10-15MPa and a temperature of 120-140℃. The heat and pressure are maintained for 5-10 minutes, and after cooling and shaping, it is cut into a finished product, which is a biodegradable stone plastic floor.

[0024] Furthermore, the mixing process in step (3) is carried out in a closed mixer, the mixing temperature is controlled at 170-190℃, and the mixing time is not less than 10 minutes.

[0025] Furthermore, the hot pressing process in step (4) adopts segmented pressure control: the initial stage pressure is 5-8MPa and the temperature is 120-130℃, lasting for 2-4 minutes; the final stage pressure rises to 12-15MPa and the temperature is 130-140℃, lasting for 3-6 minutes.

[0026] Furthermore, step (3) is performed under a nitrogen atmosphere.

[0027] The mechanism of action of the UV absorber described in this invention is based on the photophysical and chemical behavior of its molecular structure. The core is the conversion of harmful ultraviolet radiation into harmless heat energy, thereby protecting the polymer matrix and achieving long-term weather resistance. The π-π* conjugated system of the conjugated aryl groups in the molecule has a broad absorption band (290-400 nm), capable of capturing ultraviolet photons. Nitrogen-containing heterocyclic aryl groups enhance UV-B absorption efficiency through n-π* transitions. The absorbed light energy is converted into heat energy through non-radiative relaxation (such as vibrational relaxation), preventing energy accumulation that could lead to polymer degradation. Hydroxyl groups form intramolecular hydrogen bonds (such as OH···N) with adjacent nitrogen-containing heterocycles, improving molecular thermal stability and preventing photolysis or oxidation of the UV absorber itself under long-term UV irradiation, ensuring long-lasting performance. Nitrogen-containing heterocyclic aryl groups can quench UV-excited free radicals, interrupting chain reactions. Synergistically with other components in the anti-UV aging layer: silica scatters ultraviolet radiation, and epoxidized soybean oil acts as a stabilizer to reduce oxidation, forming a multi-level protective network.

[0028] This invention aims to solve the key technical problems of existing stone plastic flooring, such as insufficient resistance to ultraviolet aging (which easily leads to discoloration, cracking, powdering and reduced strength), non-degradability (which aggravates environmental pollution), and poor long-term stability. The root cause of these problems lies in the damage of ultraviolet light to the chemical bonds of materials such as polyvinyl chloride and the limited effectiveness of traditional additives. This invention achieves multi-level protection and synergistic effects through an innovative layered structure and coordinated material composition: the anti-UV aging layer (top layer) directly faces UV radiation, and its components include polylactic acid, polybutylene terephthalate, polyvinyl chloride, silica, UV absorbers, epoxidized soybean oil, and processing aid ACR. Through physical and chemical synergy, a multi-level protective network of "conversion-scattering-stabilization" is formed. The UV absorber converts harmful UV rays into harmless heat energy and quenches free radicals; silica scatters and reflects UV rays; epoxidized soybean oil provides antioxidant stability; polylactic acid and polybutylene terephthalate enhance toughness and heat resistance; and the processing aid ACR ensures uniform dispersion, thereby significantly improving anti-UV aging performance and effectively delaying discoloration, chalking, and strength loss. The substrate layer is composed of biodegradable polylactic acid materials, including polylactic acid and triethyl citrate. The material comprises esters, talc, processing aid ACR, and stearic acid. Polylactic acid provides mechanical strength, triethyl citrate improves flexibility and biodegradability, talc enhances dimensional stability, and stearic acid and ACR synergistically improve processing uniformity, ensuring the material is microbially degradable after disposal and reducing environmental pollution. The decorative layer consists of a PVC film printed with wood or stone grain patterns, providing aesthetics and a secondary UV barrier, and is tightly bonded to the upper and lower layers to prevent delamination. The preparation method ensures component effectiveness through process synergy, including mixing and extrusion under a nitrogen atmosphere to prevent oxidative degradation, and segmented pressure control during lamination to ensure molecular-level bonding and stability at the interface of each layer. Overall, the components are coordinated in four dimensions—protection, support, aesthetics, and process—to extend the floor's service life while achieving biodegradability and long-term stability, completely solving the aforementioned technical problems.

[0029] Compared with the prior art, the beneficial effects of the present invention are:

[0030] 1. Significantly improved UV resistance: By introducing a specially formulated UV absorber and a multi-level protection mechanism (including UV conversion, scattering, and chemical stabilization), this invention effectively suppresses the destructive effects of UV radiation on the floor, thereby significantly reducing surface discoloration, cracking, and powdering, and improving the overall weather resistance of the material.

[0031] 2. Environmental degradability: The base layer uses biodegradable materials such as polylactic acid, combined with optimized components (such as triethyl citrate and talc), making the flooring easier for microorganisms to decompose after disposal, significantly reducing the environmental pollution burden and conforming to the trend of sustainable development.

[0032] 3. Enhanced long-term stability: Through layered structural design and process coordination (such as segmented lamination control), this invention improves the physical properties and interfacial bonding strength of the flooring, effectively delays the degradation of mechanical properties, extends service life, and maintains a stable appearance and function in complex environments. Attached Figure Description

[0033] Figure 1 This is the NMR spectrum of the ultraviolet absorber 1 described in this invention.

[0034] Figure 2 This is a schematic diagram of the structure of a biodegradable stone-plastic flooring according to the present invention;

[0035] 1 is the substrate layer, 2 is the decorative layer, and 3 is the UV aging resistant layer. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Preparation Example 1

[0038] Preparation of UV absorber 1:

[0039]

[0040] Under a continuous nitrogen flow, 15 g of raw material 1, 16.48 g of raw material 2, 20.16 g of K3PO4 and 0.87 g of catalyst were added sequentially to a reactor containing 170 ml of toluene. After stirring evenly, the mixture was heated to 100 °C and reacted for 10 h. The mixture was filtered with diatomaceous earth, and the filtrate was collected and evaporated to dryness. The filtrate was purified by silica gel column chromatography (petroleum ether / ethyl acetate as eluent) to obtain 20.10 g of intermediate 1.

[0041] The catalyst is dichloro[bis(dicyclohexylphosphine)propane]palladium(II).

[0042] Structural identification data of intermediate 1—mass spectrometry (M / Z-MS+H) + ): 525.

[0043]

[0044] Under a continuous nitrogen flow, 20.10 g of intermediate 1, 8.69 g of raw material 3, 16.26 g of K3PO4, 1.75 g of 2-dicyclohexylphosphine-2',6'-dimethoxybiphenyl, and 0.5 g of catalyst were added sequentially to a reactor containing 230 ml of toluene. After stirring evenly, the mixture was heated to 110 °C and reacted for 12 h. The mixture was filtered with diatomaceous earth and extracted three times with water to obtain an organic layer. The organic layer was evaporated to dryness and purified by silica gel column chromatography (petroleum ether / ethyl acetate as eluent) to obtain 19.96 g of UV absorber 1.

[0045] The catalyst is tris(dibenzylene-BASEacetone)dipalladium (Pd2(dba)3).

[0046] Structural identification data of the ultraviolet absorber 1—mass spectrometry (M / Z-MS+H) + ): 633;

[0047] Structural identification data of the ultraviolet absorber 1— 1 HNMR Chloroform-d( Figure 1 ): δ8.27(dd,1H),8.06(dd,1H),7.92(dd,1H),7.61-7.55(m,4H),7.55-7.39(m,8H),7.39-7.31(m, 1H),7.20-7.08(m,4H),7.03(dd,1H),6.92(dd,1H),6.67(dd,2H),2.34(d,3H),1.49-1.41(m,9H).

[0048] Preparation Examples 2-4

[0049] In Preparation Examples 2-4, UV absorber 2-UV absorber 4 were prepared sequentially, following the preparation method of Preparation Example 1, except that raw material 3 was replaced, while the rest remained the same as in Preparation Example 1. For details, please refer to Table 1.

[0050] Table 1.

[0051]

[0052] Example 1

[0053] Preparation of a biodegradable stone-plastic flooring:

[0054] 1. Raw material composition:

[0055] 1.1 Substrate layer raw materials: 85 parts polylactic acid, 7 parts triethyl citrate, 5 parts talc, 2 parts processing aid ACR, and 2 parts stearic acid;

[0056] The polylactic acid was purchased from Xiamen Xinfuda Environmental Protection Technology Co., Ltd. PLA LX575;

[0057] The triethyl citrate was purchased from Wuhan Jixin Yibang Biotechnology Co., Ltd.

[0058] The talc powder was purchased from Laizhou Shengkai Talc Co., Ltd.

[0059] The processing aid ACR was purchased from Shandong Ruifeng Polymer Materials Co., Ltd.

[0060] The stearic acid was purchased from Shanghai Tuyi International Trade Co., Ltd.

[0061] 1.2 Decorative layer material: 0.3mm thick PVC film is used, with wood grain patterns pre-printed to simulate natural texture.

[0062] 1.3 Raw materials for the anti-UV aging layer: 85 parts of polylactic acid, 28 parts of polybutylene terephthalate, 30 parts of polyvinyl chloride, 4 parts of silicon dioxide, 1.5 parts of UV absorber (UV absorber 1), 5 parts of epoxidized soybean oil, and 2 parts of processing aid ACR.

[0063] The polylactic acid was purchased from Xiamen Xinfuda Environmental Protection Technology Co., Ltd. PLA LX575;

[0064] The polybutylene terephthalate was purchased from Wuhan Jixin Yibang Biotechnology Co., Ltd.

[0065] The polyvinyl chloride was purchased from Inner Mongolia Yili Chemical Industry Co., Ltd.

[0066] The silica was purchased from Jiangsu Puleisi Biotechnology Co., Ltd.

[0067] The epoxidized soybean oil was purchased from Nantong Haierma Technology Co., Ltd.

[0068] The processing aid ACR was purchased from Shandong Ruifeng Polymer Materials Co., Ltd.

[0069] 2. Preparation method:

[0070] (1) Preparation of substrate layer: Polylactic acid, triethyl citrate, talc, processing aid ACR and stearic acid are put into a high-speed mixer and premixed at room temperature for 5 minutes until uniform. The mixture is then transferred to a melt extruder, the temperature is set to 170℃ and the screw speed is 50rpm, and melt extrusion is performed. The extrudate is formed into a sheet substrate layer with a thickness of 2.0mm through a flat die. After cooling and shaping, it is wound up for later use.

[0071] (2) Preparation of decorative layer: Take a 0.3mm thick PVC film, place it on the printing machine table, use water-based ink to print wood grain pattern, control the printing pressure at 0.2MPa, the drying temperature at 80℃, and the drying time at 2 minutes. After printing, form a decorative layer roll for later use.

[0072] (3) Preparation of anti-UV aging layer: First, polylactic acid, polybutylene terephthalate, polyvinyl chloride, silica, UV absorber, epoxidized soybean oil and processing aid ACR are added to a closed mixer. Under a nitrogen atmosphere (flow rate 10L / min), the mixing temperature is set to 180℃, the mixing time is 12 minutes, and the stirring speed is 40rpm to ensure that the components are fully mixed. After mixing, the material is transferred to an extruder, the temperature is set to 180℃, and the film with a thickness of 0.2mm is extruded to obtain the anti-UV aging layer.

[0073] (4) Lamination: The substrate layer, decorative layer, and UV-resistant layer are stacked sequentially (substrate layer at the bottom, UV-resistant layer at the top) and placed in a hot press. Segmented pressure control is used: initially, the pressure is 6 MPa and the temperature is 125°C for 3 minutes; in the final stage, the pressure is increased to 14 MPa and the temperature to 135°C for 4 minutes; after cooling to room temperature, a composite board with a total thickness of 2.5 mm is formed. Finally, it is cut into standard-sized (1200 mm × 200 mm) finished biodegradable stone-plastic flooring using a cutting machine.

[0074] Examples 2-4

[0075] The preparation of a biodegradable stone-plastic flooring method is based on the preparation method of Example 1, except that the ultraviolet absorbers are replaced sequentially with ultraviolet absorbers 2-4, and the rest remains the same as in Example 1.

[0076] Comparative Example 1

[0077] A biodegradable stone-plastic flooring was prepared by referring to the preparation method of Example 1, except that the ultraviolet absorber was replaced sequentially with ultraviolet absorber UV-P (…). The rest remains the same as in Example 1.

[0078] Comparative Example 2

[0079] The preparation of a biodegradable stone-plastic flooring method is the same as in Example 1, except that the ultraviolet absorber is replaced with ultraviolet absorber UV-234 (CAS: 70321-86-7) in sequence, and the rest is the same as in Example 1.

[0080] Comparative Example 3

[0081] The preparation of a biodegradable stone-plastic flooring follows the same method as in Example 1, except that no ultraviolet absorber is added, and the rest remains the same as in Example 1.

[0082] Comparative Example 4

[0083] The preparation of a biodegradable stone-plastic flooring is the same as in Example 1, except that silicon dioxide is not added.

[0084] Comparative Example 5

[0085] The preparation of a biodegradable stone-plastic flooring follows the same method as in Example 1, except that polyvinyl chloride is not added, and the rest remains the same as in Example 1.

[0086] Performance testing:

[0087] Test sample: A biodegradable stone-plastic flooring prepared in the examples and comparative examples.

[0088] 1. Static bending strength: The test method is in accordance with GB / T 17657-2022, and the data are shown in Table 2.

[0089] 2. Dimensional stability: The test method is in accordance with ISO 23999, and the data are shown in Table 2.

[0090] 3. Weather resistance test: Place the sample in an aging test chamber and set the conditions as follows: 313nm UV-B lamp source (simulating high-intensity sunlight ultraviolet rays), 0.67W / m 2 The irradiance was set at 50℃, the test temperature at 65%RH, and the exposure time was 8 hours of light exposure plus 4 hours of condensation (simulating diurnal variation). The total exposure time was 4800 hours. After the exposure, the static bending strength retention rate (%) was tested, and the data are shown in Table 2.

[0091] Table 2.

[0092]

[0093] The embodiment group of the present invention exhibits significant advantages across all key performance indicators, while the comparative group performs poorly. Specifically, regarding static bending strength, the embodiments maintain a high strength level, while the comparative group shows a significant decrease in strength that continues to deteriorate with changing conditions. Dimensional stability exhibits low volatility in the embodiments, demonstrating excellent stability; while the comparative group shows increased volatility and a significant decrease in stability. Regarding strength retention, the embodiments retain a high level of strength, while the comparative group shows a significantly lower retention rate, especially a sharp decline in a specific control group. Overall, these trends clearly indicate that the specific combination of UV absorbers and materials of the present invention can effectively improve the overall performance, durability, and anti-aging capabilities of the product.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A degradable stone plastic floor, characterized in that, From bottom to top, it includes: a substrate layer (1), a decorative layer (2), and an anti-UV aging layer (3); The anti-UV aging layer (3) is made of anti-UV aging material; The anti-UV aging material comprises, by weight, 80-90 parts of polylactic acid, 25-30 parts of polybutylene terephthalate, 30 parts of polyvinyl chloride, 3-5 parts of silicon dioxide, 0.5-2 parts of UV absorber, 3-8 parts of epoxidized soybean oil, and 1-3 parts of processing aid. The ultraviolet absorber is a compound represented by Formula 1: In Formula 1, R1 is hydrogen, methyl, hydroxyl, or methoxy.

2. The degradable stone plastic floor according to claim 1, characterized in that, The epoxidized soybean oil has an epoxy value of 6.2-6.8%, an acid value of ≤0.5mg KOH / g, and an iodine value of ≤6g I2100g.

3. The degradable stone plastic floor as claimed in claim 1, wherein, The processing aid is processing aid ACR.

4. The degradable stone plastic floor as claimed in claim 1, wherein, The ultraviolet absorber is any one of the compounds shown in the following structures:

5. The degradable stone plastic floor board according to claim 1, characterized in that, The substrate layer (1) is made of biodegradable polylactic acid material; The biodegradable polylactic acid material comprises the following raw materials in parts by weight: 80-95 parts polylactic acid, 5-10 parts triethyl citrate, 2-8 parts talc, 1-3 parts processing aid ACR, and 1-3 parts stearic acid.

6. The degradable stone plastic floor board according to claim 1, characterized in that, The decorative layer (2) is made of a PVC film printed with wood grain or stone grain, with a thickness of 0.1-0.5 mm.

7. The method for preparing the degradable stone plastic floor according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Preparation of substrate layer: The polylactic acid, triethyl citrate, talc, processing aid ACR and stearic acid are mixed and melt-extruded at 160-180℃ to form a sheet substrate layer (1). (2) Preparation of decorative layer: Provide a PVC film with a thickness of 0.1-0.5mm, print wood grain or stone grain patterns to form decorative layer (2); (3) Preparation of anti-ultraviolet aging layer: The polylactic acid, polybutylene terephthalate, polyvinyl chloride, silicon dioxide, ultraviolet absorber, epoxidized soybean oil and processing aid are mixed, melt-blended at 170-190℃, and extruded into a film to obtain anti-ultraviolet aging layer (3). (4) Lamination: The substrate layer (1), decorative layer (2) and UV aging resistant layer (3) are stacked in sequence and laminated in a hot press at a pressure of 10-15MPa and a temperature of 120-140℃. The heat and pressure are maintained for 5-10 minutes, and after cooling and shaping, it is cut into a finished product, a biodegradable stone plastic floor.

8. The method for preparing a biodegradable stone-plastic flooring according to claim 7, characterized in that, The mixing process in step (3) is carried out in a closed mixer, with the mixing temperature controlled at 170-190℃ and the mixing time not less than 10 minutes.

9. The method for preparing a biodegradable stone-plastic flooring according to claim 7, characterized in that, The hot pressing process in step (4) adopts segmented pressure control: the initial stage pressure is 5-8MPa and the temperature is 120-130℃, lasting for 2-4 minutes; the final stage pressure rises to 12-15MPa and the temperature is 130-140℃, lasting for 3-6 minutes.

10. The method for preparing a biodegradable stone-plastic flooring according to claim 7, characterized in that, Step (3) is performed under a nitrogen atmosphere.

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