Bio-based thermoplastic prefabricated buffer layer and preparation method and application thereof

Abstract

According to the bio-based thermoplastic prefabricated buffer layer and the preparation method and application thereof, bio-based thermoplastic polyurethane is creatively used as a raw material of the bio-based thermoplastic prefabricated buffer layer, the proportion of the preparation raw material is further optimized, and a three-dimensional structure is formed in the thickness direction; the prefabricated bio-based thermoplastic prefabricated buffer layer can be obtained and has high elasticity (the elongation at break is larger than or equal to 500%), abrasion resistance (the abrasion loss is smaller than or equal to 0.3 g / 1000 times of rotation), weather resistance and recoverability, the hardness range is 60-80 Shore A, and the environmental protection and physical and mechanical properties of a multi-layer floor system obtained through construction of the bio-based thermoplastic prefabricated buffer layer meet the GB / T 43564-2023 standard.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane elastomers, and in particular to a bio-based thermoplastic prefabricated buffer layer and a preparation method and application thereof. Background Art

[0002] At present, many schools, kindergartens, parks, community playgrounds, basketball courts, volleyball courts, badminton courts, fitness trails / citizen exercise facilities and other places often have sports floors for students, children, adults, the elderly and other people of different ages to use for exercise. The sports floors in these scenes need to pay attention to their performance indicators such as wear resistance, sun resistance, and anti-threshing.

[0003] Thermoplastic polyurethane elastomer (TPU) has been widely used in many fields due to its high strength, high wear resistance, wide hardness range, wide processing temperature, etc. Thermoplastic polyurethane elastomer (TPU) can be divided into petrochemical-based TPU and bio-based TPU according to the source of raw materials. Bio-based TPU raw materials are extracted from plants and have the advantages of carbon circulation and sustainability, which has a significant role in promoting the control of global carbon emissions.

[0004] The prior art discloses a polyurethane plastic track, which is constructed by paving, pouring or spraying on site. However, since the peak season for construction in schools and other places is usually July and August during the summer vacation, it is easy to encounter a period of heavy rain, resulting in a long construction period. In addition, the polyurethane materials stored on site are also easily affected by the humidity in the air, resulting in uneven foaming during curing, uneven thickness and elasticity during curing, and easily causing water accumulation in local areas. The final finished product has poor foot comfort due to uneven thickness, and the tensile strength and elongation at break of the foamed buffer layer are very poor. In addition, polyurethane plastic tracks are basically constructed by using a paver to level them or liquid self-leveling, and then the next step is applied after solidification. This is especially true for the micro-foamed full-plastic or hybrid tracks that are currently in widespread use. The bonding strength between layers is not good, and delamination can easily occur, resulting in insufficient durability of the track and poor physical properties. It is not suitable for large-scale use of the track, let alone professional stadiums or plastic tracks with competition requirements.

[0005] In this regard, the prior art discloses a prefabricated rubber track, for example, a structure of 13mm thickness, 1.22m width and 15m length is first made before leaving the factory, and then directly spliced ​​on site, and the gaps at the splicing are covered by drawing white lines. However, since the traditional prefabricated rubber track is extruded and formed by vulcanizing rubber raw materials, it is easily affected by temperature, and the phenomenon of thermal expansion and contraction is relatively serious, so it is very easy to cause cracks at the joints and warping.

[0006] In summary, it is necessary to develop a bio-based thermoplastic prefabricated buffer layer and a preparation method thereof, which can be directly spliced ​​and constructed on site to obtain a prefabricated rubber track, which not only improves the construction efficiency and reduces the construction environment restrictions, but is also suitable for school playgrounds, stadiums and outdoor fitness venues. Sports floors also have the significant advantages of environmental protection, convenient construction and durability. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a bio-based thermoplastic prefabricated buffer layer and a preparation method and application thereof. The bio-based thermoplastic prefabricated buffer layer creatively uses bio-based thermoplastic polyurethane as raw material, further optimizes the ratio of the raw materials, and opens a three-dimensional structure in the thickness direction to obtain a prefabricated bio-based thermoplastic prefabricated buffer layer with high elasticity (elongation at break ≥ 500%), wear resistance (wear amount ≤ 0.3g / 1000 rotations), weather resistance and recyclability, and a hardness range of 60-80 Shore A. The environmental protection and physical and mechanical properties of the multi-layer floor system obtained by constructing the bio-based thermoplastic prefabricated buffer layer meet the GB / T 43564-2023 standard.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a bio-based thermoplastic prefabricated buffer layer. The raw materials for preparing the bio-based thermoplastic prefabricated buffer layer include, by mass percentage:

[0010] Bio-based thermoplastic polyurethane 85-95%;

[0011] Bio-based plasticizer 3-12%;

[0012] Antioxidants 0.5-2%;

[0013] Light stabilizer 0.3-1%;

[0014] Processing aids 0.2-1%;

[0015] The bio-based thermoplastic prefabricated buffer layer has a three-dimensional structure in the thickness direction, and the three-dimensional structure includes any one of a groove, a grid or a honeycomb three-dimensional structure or a combination of at least two of them.

[0016] The bio-based thermoplastic prefabricated buffer layer of the present invention creatively uses bio-based thermoplastic polyurethane as raw material, further optimizes the ratio of the raw materials, and opens a three-dimensional structure in the thickness direction, so as to obtain a prefabricated bio-based thermoplastic prefabricated buffer layer with high elasticity (elongation at break ≥ 500%), wear resistance (wear loss ≤ 0.3g / 1000 rotations), weather resistance and recyclability, and a hardness range of 60-80 Shore A.

[0017] It should be noted that the present invention can optimize the three-dimensional structural arrangement of the bio-based thermoplastic prefabricated buffer layer according to the usage scenario. By adjusting the depth, spacing and arrangement pattern of the grooves, grids or honeycomb three-dimensional structures in the buffer layer according to the performance requirements of the target application scenario, the multi-layer floor system constructed using the bio-based thermoplastic prefabricated buffer layer of the present invention can meet the performance indicators of impact absorption rate of 35-50% and vertical deformation of 0.6-3.0 mm. For example, computer-aided design (CAD) software can be used to simulate the influence of different structural parameters on the performance of the buffer layer to select the best structural arrangement.

[0018] The bio-based thermoplastic prefabricated buffer layer of the present invention includes 85-95% of bio-based thermoplastic polyurethane by mass percentage, for example, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95%.

[0019] The bio-based thermoplastic prefabricated buffer layer of the present invention includes 3-12% of bio-based plasticizer by mass, for example, 3%, 4%, 6%, 8%, 10%, 11% or 12%.

[0020] The bio-based thermoplastic prefabricated buffer layer of the present invention includes 0.5-2% of antioxidant by mass, for example, 0.5%, 0.8%, 1%, 1.1%, 1.3%, 1.5%, 1.6%, 1.8% or 2%.

[0021] The bio-based thermoplastic prefabricated buffer layer of the present invention includes 0.3-1% of light stabilizer by mass, for example, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%.

[0022] The bio-based thermoplastic prefabricated buffer layer of the present invention includes 0.2-1% of processing aids by mass, for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%.

[0023] As a preferred technical solution of the present invention, the bio-based content of the bio-based thermoplastic polyurethane is ≥40%, and its bio-based raw materials are derived from renewable resources and meet the ASTM D6866 standard. Specifically, the bio-based raw materials are derived from vegetable oil polyols, such as soybean oil polyols, castor oil polyols, palm oil polyols, rapeseed oil polyols, etc.

[0024] Preferably, the bio-based plasticizer includes a citrate plasticizer or an adipate plasticizer, specifically including any one of tributyl citrate (TBC), acetyl tributyl citrate (ATBC), triisooctyl citrate (TOBC), bio-based dioctyl adipate (DOA) or ethylene glycol dioctyl ester (DEOA) or a combination of at least two thereof. The present invention preferably uses citrate plasticizers (such as TBC, ATBC) as bio-based plasticizers, which is a reasonable and environmentally friendly solution, because such plasticizers are derived from renewable resources and meet the requirements of environmental protection and sustainable development.

[0025] Preferably, the antioxidant includes di-tert-butyl-p-cresol or triphenylphosphonic acid diester. Di-tert-butyl-p-cresol, also known as 2,6-di-tert-butyl-methylphenol, referred to as BHT; triphenylphosphonic acid diester, referred to as TPPD, is a new type of phosphite antioxidant.

[0026] Preferably, the light stabilizer includes Tinuvin 783 or HALS light stabilizer. The Tinuvin series is a series of light stabilizers and UV absorbers produced by BASF. These products are mainly used to protect polymer materials from damage by ultraviolet rays, extend the service life of materials and maintain the appearance time. Tinuvin 783 is a UV absorber. Hindered amine light stabilizers, referred to as HALS light stabilizers, are a new type of high-efficiency stabilizer that appeared in the mid-1970s. They are used for anti-aging of polymer materials such as plastics and rubbers. Their light stabilization effect is 2-4 times that of traditional absorption-type light stabilizers. HALS light stabilizers can effectively protect polymers and avoid problems such as yellowing, reduced gloss and weakened physical properties caused by ultraviolet rays in the light source.

[0027] Preferably, the processing aid comprises a rheology modifier.

[0028] As a preferred technical solution of the present invention, the hardness range of the bio-based thermoplastic prefabricated buffer layer is 60-80 Shore A, such as 60 Shore A, 65 Shore A, 70 Shore A, 75 Shore A or 80 Shore A.

[0029] As a preferred technical solution of the present invention, the thickness of the bio-based thermoplastic prefabricated buffer layer is 6-23 mm, for example, 6 mm, 7 mm, 8 mm, 10 mm, 11 mm, 13 mm, 15 mm, 16 mm, 17 mm, 18 mm, 20 mm, 21 mm or 23 mm, etc., grooves are uniformly provided on one surface of the bio-based thermoplastic prefabricated buffer layer, and a grid or honeycomb penetrating structure corresponding to the grooves is provided on the other surface, so that the filling material uniformly fills the opened three-dimensional structure; the grid or The average pore size of the honeycomb through-structure is 2-4mm, for example, 2mm, 2.5mm, 3mm, 3.5mm or 4mm; the depth of the groove is 2-6mm, for example, 2mm, 3mm, 4mm, 5mm or 6mm, and the average pore size of the groove is 10-12mm, for example, 10mm, 10.5mm, 11mm, 11.5mm or 12mm, and the spacing between two adjacent grooves is 5-15mm, for example, 5mm, 8mm, 10mm, 11mm, 13mm or 15mm.

[0030] It should be noted that the bio-based thermoplastic prefabricated buffer layer of the present invention needs to meet the requirements of high elasticity and hardness, and the three-dimensional structure preferably has a groove on one surface and a through structure on the other surface that is smaller in size but can ensure that the filling material fills the entire three-dimensional structure. In order for the filling material to infiltrate and flow, the groove coincides with the central axis of the corresponding through structure; preferably, the groove is a circular groove with a diameter of 10-12mm, and the spacing between two adjacent grooves is 5-15mm.

[0031] Furthermore, the preferred order of the three-dimensional structure is: (1) groove below + grid above, honeycomb-like through-structure; (2) grid below, honeycomb-like through-structure, groove above (3) simple grid, honeycomb-like through-structure; (4) simple groove, and in order to add filling material, the groove needs to be set on the upper surface.

[0032] In a second aspect, the present invention provides a method for preparing the bio-based thermoplastic prefabricated buffer layer as described in the first aspect, the preparation method comprising the following steps:

[0033] According to the mass percentage, bio-based thermoplastic polyurethane, bio-based plasticizer, antioxidant, light stabilizer and processing aid are weighed and mixed evenly; the obtained mixed material is subjected to a molding process to obtain a bio-based thermoplastic prefabricated buffer layer with the three-dimensional structure.

[0034] As a preferred technical solution of the present invention, the molding process includes any one of extrusion, injection molding, calendering, hot compression molding or 3D printing, or a combination of at least two thereof; the melting temperature of the molding process is 160-200°C, for example, 160°C, 170°C, 180°C, 190°C or 200°C, etc.

[0035] Specifically, the method for preparing the bio-based thermoplastic prefabricated buffer layer comprises the following steps:

[0036] a. Weigh the bio-based thermoplastic polyurethane, bio-based plasticizer, antioxidant, light stabilizer and processing aid according to the mass percentage ratio and mix them evenly to obtain a mixed material;

[0037] b. processing the mixed material into a bio-based thermoplastic prefabricated buffer layer having the three-dimensional structure at 160-200° C. by any one of extrusion, injection molding, calendering, hot compression molding or 3D printing or a combination thereof;

[0038] c. After forming, cooling and trimming are carried out to obtain a prefabricated buffer layer module that meets the thickness and structural requirements.

[0039] Regarding the molding process, the processing temperature of the extrusion process is 160-200°C, and the injection pressure during injection molding is 8-12MPa; when hot press molding is used, the mixed material is heated to 160-200°C, 5-15MPa pressure is applied and maintained for a certain period of time, so that the material fills the mold and forms the required three-dimensional structure; when the 3D printing process is used, FDM (fused deposition modeling) or SLS (selective laser sintering) technology is used to print and mold layer by layer according to the preset three-dimensional model. Further, the bio-based thermoplastic prefabricated buffer layer with a three-dimensional structure obtained by the molding process is processed as a finished product, including cooling and trimming into prefabricated modules, such as each block with a size of 500×500mm or other sizes suitable for transportation and splicing.

[0040] In a third aspect, the present invention provides a multi-layer floor system, comprising a base layer, a buffer-filling composite layer and a surface layer arranged in sequence from bottom to top; wherein the buffer-filling composite layer comprises a bio-based thermoplastic prefabricated buffer layer and a filling material filled in its three-dimensional structure; the bio-based thermoplastic prefabricated buffer layer is the bio-based thermoplastic prefabricated buffer layer described in the first aspect, or the bio-based thermoplastic prefabricated buffer layer is a bio-based thermoplastic prefabricated buffer layer prepared by the preparation method described in the second aspect.

[0041] In the present invention, the filling material is filled into the three-dimensional structure of the bio-based thermoplastic prefabricated buffer layer, such as grooves or gaps, which can effectively improve the buffering performance and stability; moreover, the environmental protection and physical and mechanical properties of the multi-layer floor system of the present invention comply with the GB / T 43564-2023 standard, and specifically meet the following performance requirements: impact absorption rate 35-50%; vertical deformation 0.6-3.0mm; weather resistance: there is no significant change in tensile strength and elongation at break after 1500h of artificial weather aging, and it can be used in school playgrounds, stadiums or outdoor fitness venues.

[0042] As a preferred technical solution of the present invention, an adhesive layer is added between the base layer and the buffer filling composite layer of the multi-layer floor system to improve the firmness of the bio-based thermoplastic prefabricated buffer layer and avoid positional displacement. Furthermore, it is preferred to lay the adhesive on the base layer and form the adhesive layer after leveling. For example, the adhesive includes component A, component B and a catalyst, which are mixed and laid on site during construction.

[0043] As a preferred technical solution of the present invention, the filling material includes a mixture of an adhesive and elastic particles; the particle size of the elastic particles is 0.5-1.5 mm, for example, 0.5 mm, 0.8 mm, 1.0 mm, 1.1 mm, 1.3 mm or 1.5 mm, etc., preferably 0.5-1.0 mm, and the mass ratio of the adhesive to the elastic particles is 1:(4-7), for example, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5 or 1:7, etc.

[0044] Further preferably, the adhesive is an environmentally friendly one-component moisture-curing polyurethane adhesive having the following characteristics: solid content, not less than 99%; viscosity, 3000-6000 mPa·s at 25°C; initial bonding strength, at 25°C, reaching 0.5 MPa or more within 1 hour. The elastic particles in the filling material are any one of the following or a combination of at least two: environmentally friendly EPDM (ethylene propylene diene monomer) rubber particles, environmentally friendly NBR (nitrile rubber) particles, ETPU (foamed thermoplastic polyurethane) particles.

[0045] It should be noted that the filling material of the present invention needs to include a mixture of an environmentally friendly one-component moisture-curing polyurethane adhesive and elastic particles with a particle size of 0.5-1.5 mm, which can ensure the elasticity and bonding properties of the filling material. If the adhesive is less, the physical and mechanical properties of the multi-layer floor system do not meet the GB / T 43564-2023 standard. If the adhesive is more, the environmentally friendly one-component moisture-curing polyurethane adhesive will foam in large quantities when it comes into contact with water, and it will become bread-like and difficult to control.

[0046] It should be noted that the mixing method of the filling material described in the present invention includes: using high-speed stirring equipment, the stirring time is 3-5 minutes, and the rotation speed is 500-1000rpm to ensure sufficient mixing of the adhesive and the elastic particles; the filling method of the filling material described in the present invention includes: using mechanical spraying or scraping to evenly fill the filling material in the three-dimensional structural gaps of the buffer layer, and the filling thickness matches the depth of the buffer layer structure to ensure a smooth surface.

[0047] In a fourth aspect, the present invention provides a construction method of the multi-layer floor system as described in the third aspect, the construction method comprising the following steps:

[0048] (1) Base layer treatment: pre-treat the surface of the base layer;

[0049] (2) Laying the buffer layer: Lay the bio-based thermoplastic prefabricated buffer layer on the surface of the base layer and perform bonding treatment on the joints to ensure the integrity of the buffer layer;

[0050] (3) Application of filling materials: preparing filling materials and filling them into the three-dimensional structure of the bio-based thermoplastic prefabricated buffer layer to form a buffer filling composite layer;

[0051] (4) Surface layer construction and curing and maintenance: The surface layer material is laid on the completed buffer filling composite layer, and after curing and maintenance, a multi-layer floor system is obtained.

[0052] As a preferred technical solution of the present invention, in step (1), the pretreatment includes: cleaning and smoothing the surface of the base layer to ensure that there is no dust, oil stains and loose objects; and judging whether to apply sealing material on the base layer according to the waterproofing requirements in actual conditions.

[0053] And / or, in step (2), the bonding treatment includes: using hot melt welding (temperature 160-200°C, pressure 0.2-0.5MPa) or environmentally friendly polyurethane adhesive to bond the joints.

[0054] And / or, in step (3), prepare an environmentally friendly single-component moisture-curing polyurethane adhesive and elastic particles with a particle size of 0.5-1.5 mm, mix them in a mass ratio of 1:4 to 1:7, preferably 1:5, and use mechanical spraying or scraping to evenly fill the mixture into the grooves, grids or honeycomb structure gaps of the buffer layer to form a buffer filling composite layer to improve the elasticity, shock absorption performance and stability of the floor.

[0055] And / or, in step (4), the surface layer material includes a polyurethane spray coating and / or a wear-resistant rubber particle material. Specifically, the thickness of the surface layer material is 2-5 mm, and the surface layer material is a spray coating of polyurethane mixed with EPDM particles or a paving layer of EPDM rubber particles. The construction method is spraying or paving to ensure that the surface layer is uniform and flat, and has good wear resistance, anti-skid performance, and weather resistance. After the construction is completed, it is cured and maintained for 4-24 hours at an ambient temperature of 5-40°C and a humidity of 30-85% to ensure that the floor achieves the expected performance.

[0056] It should be noted that the multi-layer floor system of the present invention can be recycled by mechanical crushing or thermoplastic reprocessing technology after the use period ends, and has excellent environmental protection and recycling properties. The environmental protection and physical and mechanical properties of the multi-layer floor system of the present invention meet the requirements of GB / T 43564-2023 and GB36246-2018 standards.

[0057] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0058] (1) The bio-based thermoplastic prefabricated buffer layer of the present invention creatively uses bio-based thermoplastic polyurethane as raw material, further optimizes the ratio of the raw materials, and opens a three-dimensional structure in the thickness direction, so as to obtain a prefabricated bio-based thermoplastic prefabricated buffer layer with high elasticity (elongation at break ≥ 500%), wear resistance (wear loss ≤ 0.3g / 1000 rotations), weather resistance and recyclability, and a hardness range of 60-80 Shore A.

[0059] (2) The environmental protection and physical and mechanical properties of the multi-layer floor system obtained by the present invention using the bio-based thermoplastic prefabricated buffer layer construction conform to the GB / T 43564-2023 standard, and specifically meet the following performance requirements: impact absorption rate 35-50%; vertical deformation 0.6-3.0mm; weather resistance: after 1500h of artificial weather aging, there is no significant change in tensile strength and elongation at break, and it can be used in school playgrounds, sports stadiums or outdoor fitness venues.

[0060] (3) The construction method of the multi-layer floor system described in the present invention utilizes a bio-based thermoplastic prefabricated buffer layer to be laid on the surface of the base layer, and a mixture of adhesive and elastic particles is used to fill the gaps in the buffer layer structure to improve performance, followed by surface layer construction and curing maintenance. The construction period is shortened by more than 30% compared with the traditional method.

[0061] (4) The present invention improves construction efficiency and reduces construction environment restrictions through material innovation and structural design. It is suitable for sports floors in school playgrounds, sports stadiums and outdoor fitness venues, and has significant advantages of environmental protection, convenient construction and durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 It is a schematic diagram of the three-dimensional structure of the bio-based thermoplastic prefabricated buffer layer described in Example 1 of the present invention.

[0063] Figure 2 It is a structural schematic diagram of a multi-layer floor system obtained by using the bio-based thermoplastic prefabricated buffer layer described in Example 1 of the present invention.

[0064] In the figure, 1-base layer; 2-adhesive layer; 3-buffer filling composite layer; 4-surface layer; 5-filling material. DETAILED DESCRIPTION

[0065] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0066] To better illustrate the present invention and facilitate understanding of the technical solution of the present invention, typical but non-limiting embodiments of the present invention are as follows:

[0067] Example 1

[0068] This embodiment provides a bio-based thermoplastic prefabricated buffer layer and a preparation method thereof, and the selected raw material formula and molding process are in compliance with the claims and technical solution of the present invention.

[0069] 1. Preparation of raw material ratio (by mass percentage)

[0070] Bio-based thermoplastic polyurethane (Elastollan® Bio TPU, bio-based content ≥ 40%, BASF, Germany) 90%;

[0071] Bio-based plasticizer (tributyl citrate TBC, brand Citra® PL40, purchased from Eastman Chemical Company) 8%;

[0072] Antioxidant (triphenylphosphonic acid diester TPPD, brand Dodopermix® 126, BASF, Germany) 1%;

[0073] Light stabilizer (Tinuvin 783, BASF, Germany) 0.5%;

[0074] Processing aid (rheology modifier, Additives A-501, Degussa, Germany) 0.5%.

[0075] 2. Raw material mixing and molding process

[0076] Add the above components in proportion to a high-speed mixer (model IKA® RW 20). Set the mixer speed to about 1000 rpm at room temperature and continue stirring for 5 minutes until the raw materials are fully mixed to form a uniform mixed material. Place the mixed material in a hot pressing mold, heat it to 180°C, apply a pressure of 10 MPa, and maintain the temperature and pressure conditions for about 10 minutes to allow the material to fully melt and fill the mold.

[0077] 3. Three-dimensional structure design

[0078] In this embodiment, the thickness of the obtained bio-based thermoplastic prefabricated buffer layer is 10 mm; the specific three-dimensional structure is designed as follows: a circular groove is provided on the lower surface of the bio-based thermoplastic prefabricated buffer layer, the groove depth is about 4 mm, the diameter is about 10 mm, and the spacing between adjacent grooves is 8 mm; a honeycomb through structure corresponding to the circular grooves is provided on the upper surface of the bio-based thermoplastic prefabricated buffer layer, and the average pore diameter of the honeycomb is 2 mm. The specific structural features are as follows: Figure 1 shown.

[0079] The honeycomb through-structure is combined with the groove to form a deep channel, so that the subsequent filling material can penetrate evenly into the groove through the channel, thereby achieving uniform distribution of the filling material in the groove and honeycomb structure and improving the overall performance of the floor system. The composite three-dimensional structure can effectively improve the shock absorption and resilience of the buffer layer, and also create better conditions for the filling and curing of the subsequent filling material.

[0080] 4. Cooling and trimming

[0081] After the heating and pressing molding is completed, the obtained prefabricated buffer layer is cooled to room temperature, and necessary trimming (such as edge trimming and surface cleaning) is performed on it to obtain a bio-based thermoplastic prefabricated buffer layer module (No. A1) that meets the predetermined size and structural requirements.

[0082] 5. Performance Testing

[0083] •The elongation at break is 520%, reflecting excellent high elasticity;

[0084] • Wear loss 0.25 g / 1000 rotations, with excellent wear resistance;

[0085] •The hardness is about 70 Shore A, which falls within the range of 60-80 Shore A. The elasticity and hardness are coordinated to meet the requirements of sports floors for elastic comfort.

[0086] The above performance results show that the buffer layer prepared in this example exhibits high elasticity, excellent wear resistance and good weather resistance, and is suitable for sports floor systems with strict requirements.

[0087] 6. Application Description

[0088] The A1 prefabricated buffer layer prepared in this embodiment is applied to a multi-layer floor system, such as Figure 2 As shown, the bonding layer 2 is first laid on the base layer 1, and then A1 is laid, and the environmentally friendly single-component moisture-curing polyurethane adhesive and the environmentally friendly EPDM (ethylene propylene diene monomer) rubber particles with a particle size of 0.5-1.0 mm are mixed in a mass ratio of 1:5 to form a filling material 5, which is filled in the grooves and the honeycomb through-structure to form a buffer filling composite layer 3, and then a 3mm thick polyurethane surface layer material is laid thereon, and the coating amount is 3kg / m 2 After 12 hours of curing and curing, the surface layer 4 is formed, and finally a multi-layer floor system is obtained. The multi-layer floor system meets the requirements of GB / T 43564-2023 and GB36246-2018 standards in terms of impact absorption rate, vertical deformation and weather resistance, reflecting the excellent performance and environmental protection characteristics of the prefabricated buffer layer of the present invention in practical applications.

[0089] In summary, through the raw material ratio and three-dimensional structure design of this embodiment, a bio-based thermoplastic prefabricated buffer layer that meets the various claims of the present invention can be obtained, providing an ideal intermediate buffer material for the rapid construction and high-quality use of high-performance, environmentally friendly multi-layer floor systems.

[0090] Example 2

[0091] Compared with Example 1, this example slightly adjusts the dosage of the raw material components and slightly adjusts the molding process conditions to obtain bio-based thermoplastic prefabricated buffer layers of different thicknesses and structural sizes.

[0092] 1. Preparation of raw material ratio (by mass percentage)

[0093] Bio-based thermoplastic polyurethane (Elastollan® Bio TPU, bio-based content ≥ 40%, BASF, Germany) 89%;

[0094] Bio-based plasticizer (tributyl citrate TBC, brand Citra® PL40, purchased from Eastman Chemical Company) 9%;

[0095] Antioxidant (triphenylphosphonic acid diester TPPD, brand Dodopermix® 126, BASF, Germany) 1%;

[0096] Light stabilizer (Tinuvin 783, BASF, Germany) 0.5%;

[0097] Processing aid (rheology modifier, Additives A-501, Degussa, Germany) 0.5%.

[0098] Compared with Example 1, this ratio slightly increases the amount of plasticizer (adjusted from 8% to 9%) and reduces the amount of bio-based thermoplastic polyurethane (reduced from 90% to 89%).

[0099] 2. Raw material mixing and molding process

[0100] Add the above components in proportion to a high-speed mixer (model IKA® RW 20). Set the mixer speed to about 1000 rpm at room temperature and continue stirring for 5 minutes until the raw materials are fully mixed to form a uniform mixed material. Place the mixed material in a hot pressing mold, heat to 175°C, apply 9 MPa pressure, and maintain for about 8 minutes to allow the material to fully melt and fill the mold.

[0101] 3. Three-dimensional structure design:

[0102] In this embodiment, the thickness of the obtained bio-based thermoplastic prefabricated buffer layer is 11mm; the specific three-dimensional structure design is as follows: a circular groove is opened on the lower surface of the bio-based thermoplastic prefabricated buffer layer, the groove depth is about 3.5mm, the diameter is about 10mm, and the spacing between adjacent grooves is 10mm. A honeycomb through structure corresponding to the circular grooves is opened on the upper surface of the bio-based thermoplastic prefabricated buffer layer, and the average pore diameter of the honeycomb is 2mm. This structure allows the filling material to penetrate evenly, and by slightly changing the groove depth and spacing, the shock absorption and rebound effects are further optimized.

[0103] 4. Cooling and finishing:

[0104] After the hot pressing is completed, the buffer layer module is cooled to room temperature and trimmed to obtain a bio-based thermoplastic prefabricated buffer layer numbered A2.

[0105] 5. Performance testing:

[0106] • Elongation at break is about 510%, maintaining high elasticity;

[0107] • Wear loss 0.26 g / 1000 rotations, similar to A1, good wear resistance;

[0108] •The hardness is about 68 Shore A, which is within the range of 60-80 Shore A, meeting the requirements of elasticity and comfort.

[0109] 6. Application Description:

[0110] The prepared A2 prefabricated buffer layer was applied to the multi-layer floor system as in Example 1. Actual tests showed that the impact absorption rate, vertical deformation and weather resistance of the multi-layer system were similar to those of Example 1, further verifying the flexibility and stability of the formula and structural design.

[0111] Example 3

[0112] Compared with Example 1, this example slightly adjusts the dosage of the raw material components and tries another molding process (such as extrusion molding + hot compression molding composite process) to prove that the preparation method of the present invention has diversity.

[0113] 1. Preparation of raw material ratio (by mass percentage)

[0114] Bio-based thermoplastic polyurethane (Elastollan® Bio TPU, bio-based content ≥ 40%, BASF, Germany) 90%;

[0115] Bio-based plasticizer (tributyl citrate TBC, brand Citra® PL40, purchased from Eastman Chemical Company) 8%;

[0116] Antioxidant (triphenylphosphonic acid diester TPPD, brand Dodopermix® 126, BASF, Germany) 1.5%;

[0117] Light stabilizer (Tinuvin 783, BASF, Germany) 0.3%;

[0118] Processing aid (rheology modifier, Additives A-501, Degussa, Germany) 0.2%.

[0119] This formulation slightly increases the amount of antioxidant and reduces the amount of light stabilizer and processing aid to test the effect on performance.

[0120] 2. Raw material mixing and molding process

[0121] The above components were added to a high-speed mixer (model IKA® RW 20) in proportion. At room temperature, the mixer speed was set to about 1000 rpm, and stirring was continued for 3 minutes until the raw materials were fully mixed. Then, the raw materials were extruded through an extruder at about 165°C. The strip-shaped bio-based TPU mixture was used as the raw material. The semi-finished product obtained by extrusion was placed in a hot pressing mold and hot pressing molding was performed at 180°C, 10 MPa, and 10 minutes to ensure that the material was fully melted and densely formed.

[0122] 3. Three-dimensional structure design:

[0123] In this embodiment, the thickness of the obtained bio-based thermoplastic prefabricated buffer layer is 11 mm; the specific three-dimensional structure is designed as follows: a circular groove is opened on the lower surface of the bio-based thermoplastic prefabricated buffer layer, the groove depth is about 4 mm, the diameter is about 10 mm, the spacing between adjacent grooves is 6 mm, and a honeycomb through structure corresponding to the circular grooves is opened on the upper surface of the bio-based thermoplastic prefabricated buffer layer, and the average pore diameter of the honeycomb is 2 mm. By slightly reducing the spacing and deepening the grooves, the filling material is more evenly distributed in the thicker layer, thereby improving the shock absorption effect of the thick buffer layer.

[0124] 4. Cooling and finishing:

[0125] After the molding is completed, the material is cooled and trimmed to obtain a bio-based thermoplastic prefabricated buffer layer numbered A3.

[0126] 5. Performance testing:

[0127] •Elongation at break is about 500%, still maintaining high elasticity;

[0128] • Wear loss is about 0.28 g / 1000 rotations, slightly lower than A1 but still in the range of ≤0.3 g / 1000 rotations;

[0129] •The hardness is about 72 Shore A, slightly higher than A1 but still within the range of 60-80 Shore A, with good elasticity and durability.

[0130] 6. Application Description:

[0131] The prepared A3 prefabricated buffer layer was applied to the multi-layer floor system as in Example 1. Actual tests showed that the impact absorption rate and weather resistance of the system still met the corresponding standard requirements, proving that the present invention still has excellent performance under the extrusion + hot pressing molding composite process.

[0132] Example 4

[0133] Compared with Example 1, this example fine-tunes the dosage of the raw material components and attempts to use a design combining a grid-like through-structure and grooves to provide a reference for meeting the rigid-flexible balance requirements of different venues (such as professional courts).

[0134] 1. Preparation of raw material ratio (by mass percentage)

[0135] Bio-based thermoplastic polyurethane (Elastollan® Bio TPU, bio-based content ≥ 40%, BASF, Germany) 92%;

[0136] Bio-based plasticizer (tributyl citrate TBC, brand Citra® PL40, purchased from Eastman Chemical Company) 6%;

[0137] Antioxidant (triphenylphosphonic acid diester TPPD, brand Dodopermix® 126, BASF, Germany) 1%;

[0138] Light stabilizer (Tinuvin 783, BASF, Germany) 0.8%;

[0139] Processing aid (rheology modifier, Additives A-501, Degussa, Germany) 0.2%.

[0140] The plasticizer in this formula is slightly reduced and the light stabilizer is increased, which is beneficial to improve weather resistance in high UV environments.

[0141] 2. Raw material mixing and molding process:

[0142] Add the above components in proportion to a high-speed mixer (model IKA® RW 20), set the mixer speed to about 1000 rpm at room temperature, and continue stirring for 3 minutes until the raw materials are fully mixed. Place the resulting mixed material in a hot press mold, heat to 190°C, apply 8 MPa pressure, and maintain for about 12 minutes to completely melt and shape the material.

[0143] 3. Three-dimensional structure design:

[0144] In this embodiment, the thickness of the obtained bio-based thermoplastic prefabricated buffer layer is 10 mm; the specific three-dimensional structure is designed as follows: a circular groove is opened on the lower surface of the bio-based thermoplastic prefabricated buffer layer, the groove depth is about 3.5 mm, the diameter is about 10 mm, the distance between adjacent grooves is 10 mm, and a grid-like through-structure corresponding to the circular grooves is opened on the upper surface of the bio-based thermoplastic prefabricated buffer layer, and the average pore diameter of the grid is 2 mm. The grid-like structure helps to slightly increase the compression stiffness and provide slightly higher rebound and support for professional ball sports venues.

[0145] 4. Cooling and finishing:

[0146] After the molding is completed, the material is cooled and trimmed to obtain a bio-based thermoplastic prefabricated buffer layer numbered A4.

[0147] 5. Performance testing:

[0148] • Elongation at break is about 505%, maintaining high elasticity;

[0149] • Wear loss is about 0.27g / 1000 rotations, with excellent wear resistance;

[0150] •The hardness is about 69 Shore A, which is still within the range of 60-80 Shore A and is suitable for sports venues.

[0151] 6. Application Description:

[0152] As in Example 1, the prepared A4 prefabricated buffer layer is applied to the multi-layer floor system. The grid structure improves local stiffness and durability, and the impact absorption rate and weather resistance tests meet the standard requirements, further expanding the applicability of the present invention in different sites and usage requirements.

[0153] Through the above examples, it can be seen that the technical solution of the present invention has strong adaptability and flexibility in raw material ratio (bio-based TPU, plasticizer, antioxidant, light stabilizer, processing aid), molding process (temperature, pressure, time, mixing method), and three-dimensional structure design (grooves, honeycombs or grids, apertures, spacing, thickness). In each embodiment, whether it is slightly adjusting the amount of raw materials, changing the molding conditions, or fine-tuning the three-dimensional structure, a bio-based thermoplastic prefabricated buffer layer with stable performance and meeting the requirements of relevant standards can be obtained in the end, providing reliable technical support for the construction and long-term use of multi-layer sports floor systems.

[0154] Comparative Examples 1-5

[0155] A bio-based thermoplastic prefabricated buffer layer and a preparation method thereof, compared with Example 1, the difference is only that the preparation raw materials of the bio-based thermoplastic prefabricated buffer layer are different, or the difference is only that the three-dimensional structure of the bio-based thermoplastic prefabricated buffer layer is different, as shown in Table 1. In Comparative Examples 1-5, except for the raw material formula or three-dimensional structure different from that of Example 1, other preparation steps (including raw material mixing, heating, press molding, cooling and trimming, etc.) are the same as those of Example 1. Table 1 summarizes the differences between Example 1 and Comparative Examples 1-5 in raw material ratio and three-dimensional structure design.

[0156] Table 1

[0157]

[0158] The prefabricated buffer layers obtained in the above embodiments and comparative examples were tested at room temperature according to the following test methods: elongation at break test (refer to GB / T 528-2009 standard), wear test (refer to GB / T 1689-2014 standard) and hardness test (refer to GB / T 2411-2008 standard); the specific test results are summarized in Table 2.

[0159] Table 2

[0160]

[0161] From Table 2, we can see the following points:

[0162] (1) The bio-based thermoplastic prefabricated buffer layer (A1) of Example 1 exhibits excellent elongation at break, wear loss, hardness and buffering performance, with elongation at break ≥500%, wear loss ≤0.3 g / 1000 rotations, and hardness of about 70 Shore A, reflecting high elasticity, wear resistance and a suitable hardness range.

[0163] (2) In Comparative Example 1, no plasticizer, antioxidant, light stabilizer or processing aid is added. Although there are grooves on the lower surface and a honeycomb structure running through it, due to the lack of auxiliary components, the material's cushioning properties, hardness and wear resistance are poor, and its elongation at break and wear resistance are not as good as those in Example 1.

[0164] (3) In Comparative Example 2, the amounts of plasticizer, antioxidant, light stabilizer and processing aid were increased (80:16:2:1:1), while in Comparative Example 3, the amounts of plasticizer, antioxidant, light stabilizer and processing aid were reduced (96:2:1:0.5:0.5). Both of them exceeded the ratio range of the raw materials prepared by the present invention, which would lead to unbalanced material properties, processing difficulties or counterproductive performance. Ultimately, the elongation at break, hardness, wear resistance and cushioning performance were not as good as those in Example 1.

[0165] (4) In comparative example 4, no grooves are provided, only a honeycomb structure is provided, and the raw material ratio is the same as that in example 1. Although there is a honeycomb structure channel, the groove structure is lacking in coordination, and the overall infiltration and distribution of the filling material are not as good as the coordinated effect of the groove + honeycomb structure, and the final buffering performance is slightly inferior to that in example 1.

[0166] (5) Comparative Example 5 has only the same raw material ratio as Example 1, but does not have any three-dimensional structure (neither grooves, grids, nor honeycombs). The lack of a three-dimensional structure will result in the subsequent filling material being unable to be evenly distributed and infiltrated, and the cushioning and shock absorption performance is significantly lower than that of Example 1.

[0167] From the above results, it can be seen that the bio-based thermoplastic prefabricated buffer layer obtained in Example 1 of the present invention achieves or exceeds the expected effects in terms of elasticity, wear resistance and appropriate hardness by optimizing the raw material ratio and three-dimensional structure design, and meets the technical indicators and performance requirements stated in the claims.

[0168] Application Example 1

[0169] A multi-layer floor system and a construction method thereof, the multi-layer floor system comprising a base layer, an adhesive layer, a buffer filling composite layer and a surface layer arranged in sequence from bottom to top; wherein the buffer filling composite layer comprises a bio-based thermoplastic prefabricated buffer layer prepared in Example 1 and a filling material filled in its three-dimensional structure; the filling material comprises a mixture of an environmentally friendly single-component moisture-curing polyurethane adhesive and environmentally friendly EPDM (ethylene propylene diene monomer) rubber particles with a particle size of 1.5 mm, and the mass ratio of the two is 1:5;

[0170] The construction method comprises the following steps:

[0171] (1) Base layer treatment: pre-treat the surface of the base layer and apply sealing material; then lay the bonding layer;

[0172] (2) Laying the buffer layer: Lay the bio-based thermoplastic prefabricated buffer layer on the surface of the base layer, and use hot-melt welding to bond the joints to ensure the integrity of the buffer layer;

[0173] (3) Application of filling materials: preparing filling materials and filling them into the three-dimensional structure of the buffer layer to form a buffer filling composite layer;

[0174] (4) Surface layer construction and curing maintenance: The surface layer material is laid on the filled buffer filling composite layer. The surface layer material is a polyurethane spray coating material with a thickness of 2.5 mm and a coating amount of 2.5 kg / m 2 , with excellent weather resistance and anti-slip properties. After 12 hours of curing and maintenance, a multi-layer floor system is obtained.

[0175] Comparative Application Examples 1-4

[0176] A multi-layer floor system and a construction method thereof, compared with Application Example 1, the difference is only in the structural characteristics of the multi-layer floor system, as shown in Table 3; the construction method is the same as that of Application Example 1.

[0177] Table 3

[0178]

[0179] In accordance with GB / T 43564-2023 standard, the above application examples and comparative application examples were tested, specifically testing the impact absorption rate, vertical deformation, and weather resistance (artificial weather aging for 1500h). The specific test results are shown in Table 4.

[0180] Table 4

[0181]

[0182] From Table 4 we can see the following points:

[0183] (1) Application Example 1 achieved the best performance under the dual effects of the groove and honeycomb through-structure, and the optimized ratio of adhesive to elastic particles of 1:5. Its impact absorption rate, vertical deformation and weather resistance all met or exceeded the requirements of GB / T 43564-2023 standard, showing excellent comprehensive performance.

[0184] (2) Due to the lack of three-dimensional structure and filling materials, the overall performance of the system in comparative application example 1 is significantly reduced, especially in terms of impact absorption and weather resistance. Although the vertical deformation is low (1.8 mm), which indicates that the material is relatively rigid, the overall weather resistance is not effectively improved due to the lack of structural support and stress dispersion mechanism.

[0185] (3) Although Application Example 2 has a groove and honeycomb through-structure, it lacks the support of adhesive and the filling particles are loose, resulting in average impact absorption capacity and weather resistance, large vertical deformation, and overall performance lower than that of Application Example 1.

[0186] (4) The adhesive ratio of Application Example 3 is relatively high (1:3), which may cause uneven foaming and "breading" phenomenon, resulting in reduced weather resistance and overall performance inferior to that of Application Example 1.

[0187] (5) In comparison with Application Example 4, the adhesive ratio is too low (1:8), and the adhesion and distribution uniformity of the filling layer are still not as good as the stability and durability brought by the 1:5 ratio.

[0188] From the above comparison, it can be seen that the multi-layer floor system (Application Example 1) with a buffer layer and a filling material ratio obtained in Example 1 of the present invention is significantly better than the comparative application example in various performance indicators, which further verifies the rationality, feasibility and significant superiority of the scheme of the present invention.

[0189] The present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0190] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0191] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0192] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A bio-based thermoplastic prefabricated buffer layer, characterized in that: Calculated by mass percentage, the raw materials for preparing the bio-based thermoplastic prefabricated buffer layer include: Bio-based thermoplastic polyurethane 85-95%; Bio-based plasticizer 3-12%; Antioxidants 0.5-2%; Light stabilizer 0.3-1%; Processing aids 0.2-1%; The bio-based thermoplastic prefabricated buffer layer has a three-dimensional structure in the thickness direction, and the three-dimensional structure includes any one of a groove, a grid or a honeycomb three-dimensional structure or a combination of at least two of them.

2. The bio-based thermoplastic prefabricated buffer layer according to claim 1, characterized in that: The bio-based content of the bio-based thermoplastic polyurethane is ≥40%, and its bio-based raw materials are derived from renewable resources; the bio-based plasticizer includes a citrate plasticizer or an adipic acid ester plasticizer; the antioxidant includes di-tert-butyl-p-cresol or triphenylphosphonic acid diester; the light stabilizer includes Tinuvin 783 or a HALS light stabilizer; and the processing aid includes a rheology modifier.

3. The bio-based thermoplastic prefabricated buffer layer according to claim 1, characterized in that: The hardness of the bio-based thermoplastic prefabricated buffer layer ranges from 60 to 80 Shore A.

4. The bio-based thermoplastic prefabricated buffer layer according to claim 1, characterized in that: The thickness of the bio-based thermoplastic prefabricated buffer layer is 6-23mm; grooves are evenly opened on one surface of the bio-based thermoplastic prefabricated buffer layer, and a grid or honeycomb penetrating structure corresponding to the grooves is opened on the other surface, so that the filling material evenly fills the opened three-dimensional structure; the average pore size of the grid or honeycomb penetrating structure is 2-4mm; the depth of the groove is 2-6mm, the average pore size of the groove is 10-12mm, and the distance between two adjacent grooves is 5-15mm.

5. A method for preparing a bio-based thermoplastic prefabricated buffer layer according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: According to the mass percentage, bio-based thermoplastic polyurethane, bio-based plasticizer, antioxidant, light stabilizer and processing aid are weighed and mixed evenly; the obtained mixed material is subjected to a molding process to obtain a bio-based thermoplastic prefabricated buffer layer with the three-dimensional structure.

6. The preparation method according to claim 5, characterized in that: The molding process includes any one of extrusion, injection molding, calendering, hot compression molding or 3D printing or a combination of at least two thereof; the melting temperature of the molding process is 160-200°C.

7. A multi-layer floor system, characterized in that: It comprises a base layer, a buffer filling composite layer and a surface layer which are arranged in sequence from bottom to top; wherein the buffer filling composite layer comprises a bio-based thermoplastic prefabricated buffer layer and a filling material filled in its three-dimensional structure; the bio-based thermoplastic prefabricated buffer layer is the bio-based thermoplastic prefabricated buffer layer as described in any one of claims 1 to 4, or the bio-based thermoplastic prefabricated buffer layer is the bio-based thermoplastic prefabricated buffer layer prepared by the preparation method described in claim 5 or 6.

8. The multi-layer floor system according to claim 7, characterized in that: The filling material includes a mixture of adhesive and elastic particles; the particle size of the elastic particles is 0.5-1.5 mm; the mass ratio of the adhesive to the elastic particles is 1:(4-7).

9. A construction method of a multi-layer floor system as claimed in claim 7 or 8, characterized in that: The construction method comprises the following steps: (1) Base layer treatment: pre-treat the surface of the base layer; (2) Laying the buffer layer: Lay the bio-based thermoplastic prefabricated buffer layer on the surface of the base layer and perform bonding treatment on the joints to ensure the integrity of the buffer layer; (3) Application of filling materials: preparing filling materials and filling them into the three-dimensional structure of the bio-based thermoplastic prefabricated buffer layer to form a buffer filling composite layer; (4) Surface layer construction and curing and maintenance: The surface layer material is laid on the completed buffer filling composite layer, and after curing and maintenance, a multi-layer floor system is obtained.

10. The construction method according to claim 9, characterized in that: In step (1), the pretreatment includes: cleaning and leveling the surface of the base layer; And / or, in step (2), the bonding treatment includes: bonding the joints by hot-melt welding or environmentally friendly polyurethane adhesive; And / or, in step (4), the surface layer material includes a polyurethane spray coating and / or a wear-resistant rubber particle material; And / or, in step (4), the laying thickness of the surface layer material is 2-5 mm; And / or, in step (4), the curing and curing comprises: curing and curing for 4-24 hours at 5-40°C and a relative humidity of 30-85%.

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