TPU floor with low shrinkage rate and preparation method thereof

Abstract

The invention discloses a low-shrinkage TPU (thermoplastic polyurethane) floor and a preparation method thereof, and belongs to the technical field of TPU floors. Comprising a TPU surface layer and a TPU bottom layer, the TPU surface layer comprises a TPU main material and a PBS ingredient, and the content of the PBS ingredient in the TPU surface layer is 20-25%; the TPU bottom layer comprises a TPU main material and a PBS (Phosphate Buffer Solution) ingredient, and the content of the PBS ingredient in the TPU bottom layer is 40-45%; the thickness ratio of the TPU surface layer to the TPU bottom layer is 3: 2; the TPU surface layer and the TPU bottom layer are integrally manufactured through a hot-press forming machine; pBS precipitation processing of the TPU surface layer and the TPU bottom layer is completed before hot press molding of the TPU surface layer and the TPU bottom layer, and during processing, the TPU surface layer and the TPU bottom layer are fed into a processing roller row. According to the low-shrinkage-rate TPU floor and the preparation method thereof, PBS ingredients serve as a rigid framework supporting system in the TPU floor, the TPU floor can have the excellent characteristics of itself, and meanwhile, the TPU surface layer and the TPU bottom layer are not prone to falling off; the low shrinkage rate of the TPU floor can be reduced, and meanwhile the structural strength of the TPU floor can be improved.

Description

Technical Field

[0001] The invention specifically relates to a TPU floor with a low shrinkage rate and a preparation method thereof, and belongs to the technical field of TPU floors. Background Art

[0002] TPU floor is made of TPU material and other additives. TPU floor has excellent wear resistance, scratch resistance and pollution resistance, can maintain the beauty and gloss of the floor for a long time, and has good elasticity and resilience, can relieve the pressure and fatigue of the feet, and improve the comfort of walking; in addition, compared with rubber floor, TPU floor has better pollution resistance, scratch resistance, aging resistance and fire resistance; the existing TPU floor has a certain shrinkage rate, and there is no effective method to reduce the shrinkage rate. The TPU floor cloth is usually treated by cooling and shaping method, but the surface of the prepared TPU floor is too rough, which affects the subsequent printing; in order to reduce the shrinkage rate of TPU floor, China Patent Publication No.: CN111055574A discloses a low shrinkage TPU floor, which includes TPU wear-resistant layer, color film layer, TPU stabilizing layer and PVC bottom layer from top to bottom; The TPU stabilization layer adds glass fiber and carbon fiber, which is more evenly dispersed than single glass fiber, improves the tensile tear strength of the material, and makes the PVC glass fiber middle layer have a lower shrinkage rate; however, the processing of the TPU floor is relatively complicated, and the use of the TPU stabilization layer for shrinkage resistance is prone to interlayer peeling, and the single-layer shrinkage rate of the TPU floor is still relatively high; in addition, when the existing TPU main material is mixed, the mixer is heated by an external heat source. During heating, the air is used as the heat transfer medium inside the mixer, and the heat is transferred from the surface of the TPU main material to the inside, and the heat inside the TPU main material is lower than the heat on the surface; when the core of the TPU main material begins to grow bubble pores, and the bubble pores on the surface of the TPU main material are too large or even damaged, thereby increasing the shrinkage rate of the TPU main material, especially when the TPU main material is overheated and the heating time is too long, the TPU main material first melts and then solidifies, so that a hard film is formed on the surface of the TPU main material; directly affecting the compatibility between the TPU main materials and the shrinkage rate of the TPU floor. Summary of the invention

[0003] In order to solve the above problems, the present invention proposes a TPU floor with a low shrinkage rate and a preparation method thereof. By using PBS ingredients as a rigid skeleton support system inside the TPU floor, the TPU floor can have its own excellent properties while reducing the low shrinkage rate of the TPU floor and improving the structural strength of the TPU floor.

[0004] The low-shrinkage TPU floor of the present invention comprises: A TPU surface layer, wherein the components of the TPU surface layer include a TPU main material and a PBS ingredient, wherein the content of the PBS ingredient in the TPU surface layer is 20-25%; by using the PBS ingredient as an ingredient of the TPU main material, the PBS ingredient can thicken the foam cell wall of the TPU main material, thereby reducing the shrinkage rate of the TPU surface layer; The components of the TPU bottom layer include a TPU main material and a PBS ingredient, and the content of the PBS ingredient in the TPU bottom layer is 40-45%; the specific gravity of the PBS ingredient in the TPU bottom layer is greater than that in the TPU surface layer; thereby, the thickness of the foam cell wall of the TPU main material can be further increased, and the shrinkage rate of the TPU surface layer can be further reduced. The PBS ingredient can fully restrain the TPU main material, thereby reducing the shrinkage rate of the TPU surface layer; The thickness ratio of the TPU surface layer to the TPU bottom layer is 3:2; the TPU surface layer and the TPU bottom layer are integrally formed by a hot pressing molding machine; Before the TPU surface layer and the TPU bottom layer are hot-pressed, the PBS precipitation processing of the TPU surface layer and the TPU bottom layer is first completed. During the processing, the TPU surface layer and the TPU bottom layer are respectively sent to the processing roller row. After the processing is completed, the precipitation surfaces of the TPU surface layer and the TPU bottom layer are obtained. Then, the precipitation surfaces of the TPU surface layer and the TPU bottom layer are brought close to each other, and the precipitation surfaces of the TPU surface layer and the TPU bottom layer are passed through an intermediate heating roller group. After being heated by the intermediate heating roller group, they are sent to a hot pressing molding machine to complete integrated hot pressing molding to obtain a TPU floor cloth; When processing the TPU floor cloth, the TPU surface layer and the TPU bottom layer are processed independently. Since the melting point of the TPU main material is greater than the melting point of the PBS ingredient, the bottom of the roller row is heated and the top is cooled through processing, and the temperature is controlled to exceed the melting critical point of the PBS ingredient and be lower than the melting critical point of the TPU main material; the TPU surface layer and the TPU bottom layer form a PBS precipitation layer on one side of the TPU surface layer and the TPU bottom layer through flow penetration, and the PBS precipitation layer of the TPU surface layer and the TPU bottom layer forms an interlaced and fused bonding surface with the TPU main material, which can avoid the precipitation layer from peeling off; then, the heating temperature of the middle heating roller group is controlled, and the PBS precipitation layer is heated and melted for the second time through the middle heating roller group, which can plasticize the PBS precipitation layer, and since the PBS precipitation layer is in a molten state, the TPU surface layer and the TPU bottom layer are then sent to a hot pressing molding machine to complete integrated hot pressing molding, so that the two groups of PBS precipitation layers are hot-pressed and combined into one, so that the TPU surface layer and the TPU bottom layer form an anti-peeling TPU floor cloth.

[0005] Furthermore, the processing roller pair row includes 5 to 8 groups of precipitation roller pairs, and 3 to 5 groups of cooling roller pairs are arranged at the output end of the precipitation roller pairs; the upper roller of the precipitation roller pairs is a cold roller, and the lower roller of the precipitation roller pairs is a temperature-controlled heating roller. The heating temperature of the temperature-controlled heating roller is 110 to 115°C, and the upper roller and the lower roller of the cooling roller pairs are both cold rollers; the intermediate heating roller group is composed of multiple temperature-controlled heating rollers.

[0006] Furthermore, a mesh cloth is arranged between the TPU surface layer and the TPU bottom layer; the mesh cloth is heat-pressed between the TPU surface layer and the TPU bottom layer.

[0007] Furthermore, the mesh cloth is a carbon fiber mesh cloth or a glass fiber mesh cloth.

[0008] A method for preparing a TPU floor with a low shrinkage rate is used to prepare a TPU floor with a low shrinkage rate. The method includes preparing a TPU surface layer and a TPU bottom layer, and hot pressing the TPU surface layer and the TPU bottom layer to form a TPU floor cloth; the TPU surface layer and the TPU bottom layer are prepared in the same way, and the specific process is as follows: S1: Mixing at room temperature: putting the TPU main material and PBS ingredients into a three-dimensional mixer, and fully mixing the TPU main material and PBS ingredients through the three-dimensional mixer at room temperature to obtain a mixture; S2: Protect the internal mixer. Put the mixture into the internal mixer and introduce the steam system into the internal mixer. Control the steam temperature at 110~115℃ and keep the heating time at 2~2.5min. At this time, control the internal mixer speed at 5~10 rpm. When the mixture is softened, convert the steam heating to external heating of the internal mixer. During the conversion process, the steam heating is continuously reduced and the external heating source is used to supplement the heat source until the internal temperature of the internal mixer is always maintained at 110~115℃. Until the steam heating is completely turned off, then control the external heating source to reduce the internal temperature of the internal mixer to 105~110℃. Then, increase the internal mixer speed to 25~30 rpm. Keep the internal mixer time at 5~8min to complete the internal mixer to obtain the low shrinkage floor rubber. When the internal mixer processes the mixture, high Warm water vapor is directly sprayed on the TPU main material to achieve the purpose of heating. The high-temperature water vapor has strong penetrability and can quickly fill the entire internal mixer. The water vapor has fast heat transfer and can be evenly distributed around the TPU main material. The TPU main material is evenly heated, which can protect the TPU main material and avoid the bursting of the bubble holes of the TPU main material, resulting in the inability to control the shrinkage rate of the TPU floor. In the early stage of the mixture processing, the internal mixer is kept at a low speed, and the high-temperature water vapor is first filled into the internal mixer. At this time, the stirring system of the internal mixer will not mechanically impact the TPU main material. When the TPU main material is fully heated and melted, and the surface humidity of the mixture is maintained, it is converted to an external heating source again, and the surface humidity is used to protect the surface of the mixture. At the same time, the speed of the internal mixer is increased to fully melt the mixture into one, forming a low-shrinkage floor rubber. S3: TPU surface layer and TPU bottom layer are formed, the low shrinkage floor rubber material is fed into the extruder for extrusion and then pressed into the required thickness and width by the pressing machine to obtain the TPU surface layer and TPU bottom layer; S4: TPU surface layer and TPU bottom layer precipitation processing, the TPU surface layer and TPU bottom layer are sent to the processing roller row to complete the TPU surface layer and TPU bottom layer precipitation surface processing, then the processed TPU surface layer and TPU bottom layer are rolled up to obtain TPU surface layer coils and TPU bottom layer coils; The processing process of the TPU floor cloth is as follows: the TPU surface layer and the TPU bottom layer are simultaneously fed into a heating roller, the precipitation surfaces of the TPU surface layer and the TPU bottom layer are processed by the heating roller to make the precipitation surfaces in a semi-molten state, then the TPU surface layer and the TPU bottom layer are fed into a hot pressing molding machine, the semi-molten precipitation surfaces of the TPU surface layer and the TPU bottom layer are hot pressed by the hot pressing molding machine, and then the TPU floor cloth is obtained by cooling, cutting and printing.

[0009] Compared with the prior art, the low-shrinkage TPU floor and preparation method thereof of the present invention are as follows: the TPU main material and the PBS ingredients are first fully mixed, and then the PBS ingredients are precipitated under temperature control; the PBS ingredients can be fully combined with the TPU main material to form a three-dimensional network state combination, which can achieve the anti-peeling of the precipitation layer and the TPU main material; at the same time, by utilizing the full combination of the precipitation layer and the TPU main material, the TPU main material can be fully bound, thereby reducing the shrinkage of the TPU surface layer; in addition, the PBS ingredients can be plasticized separately for a second time to form a structural layer between the TPU surface layer and the TPU bottom layer, thereby improving the stiffness and anti-shrinkage ability of the TPU floor cloth after stretching; and the TPU surface layer and the TPU bottom layer can be integrally hot-pressed through the precipitation surface between the TPU surface layer and the TPU bottom layer; The TPU bottom layer and the TPU surface layer adopt a sandwich structure, which can make the bottom layer and the surface layer of the TPU floor comfortable, while also having wear resistance and anti-slip, excellent tension, pulling force and good elasticity; the PBS ingredient amount of the TPU bottom layer is greater than the PBS ingredient amount of the TPU surface layer, and the TPU bottom layer can provide binding ability for the TPU surface layer; in addition, the internal structural strength and shrinkage resistance of the TPU floor cloth can be achieved through the mesh cloth between the TPU surface layer and the TPU bottom layer; when the TPU main material is mixed, the problem of excessive shrinkage of the TPU floor cloth after processing can be avoided due to the bursting of bubbles on the surface of the TPU main material. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the overall structure of the TPU surface layer of the present invention.

[0011] Figure 2 It is a schematic diagram of the overall structure of the TPU bottom layer of the present invention.

[0012] Figure 3 It is a schematic diagram of the overall structure of the low-shrinkage TPU floor of the present invention.

[0013] Figure 4 It is a schematic diagram of the installation structure of the low-shrinkage TPU floor and mesh cloth of the present invention.

[0014] Figure 5 It is a schematic diagram of the overall structure of the processing roller row of the present invention.

[0015] Figure 6 It is a schematic diagram of the hot pressing molding structure of the TPU floor cloth of the present invention.

[0016] Figure 7 The figure is a schematic flow chart of the method for preparing the TPU floor with low shrinkage rate of the present invention.

[0017] Figure numerals: 1. TPU surface layer, 2. TPU bottom layer, 3. precipitation surface, 4. mesh cloth, 5. processing roller row, 6. precipitation roller pair, 7. cooling roller pair, 8. intermediate heating roller group, 9. hot pressing molding machine, 10. TPU floor cloth. DETAILED DESCRIPTION

[0018] Embodiment 1: like Figures 1 to 7 The low shrinkage TPU floor shown includes: TPU surface layer 1, the components of the TPU surface layer 1 include a TPU main material and a PBS ingredient, and the content of the PBS ingredient in the TPU surface layer 1 is 20-25%; by using the PBS ingredient as an ingredient of the TPU main material, the PBS ingredient can thicken the foam cell wall of the TPU main material, thereby reducing the shrinkage rate of the TPU surface layer 1; TPU bottom layer 2, the components of the TPU bottom layer 2 include TPU main material and PBS ingredients, the content of PBS ingredients in the TPU bottom layer 2 is 40-45%; the specific gravity of the PBS ingredients in the TPU bottom layer 2 is greater than that in the TPU surface layer 1; thereby, the foam cell wall thickness of the TPU main material can be further increased, and the shrinkage rate of the TPU surface layer 1 can be further reduced. The TPU main material can be fully bound by the PBS ingredients, thereby reducing the shrinkage rate of the TPU surface layer 1; wherein the TPU main material is an existing TPU floor ingredient, such as TPU resin as the main material, and lubricants, stabilizers, diisocyanates, oligomer diols and masterbatches are added to the main material; for example, auxiliary ingredients such as glass fiber and calcium carbonate are added to the TPU main material. Since the TPU main material adopts TPU floor ingredients, the specific components and formulas are not described in detail here; The thickness ratio of the TPU surface layer 1 and the TPU bottom layer 2 is 3:2; the TPU surface layer 1 and the TPU bottom layer 2 are integrally formed by a hot pressing molding machine; Before the TPU surface layer 1 and the TPU bottom layer 2 are hot-pressed, the PBS precipitation processing of the TPU surface layer 1 and the TPU bottom layer 2 is first completed. During the processing, the TPU surface layer 1 and the TPU bottom layer 2 are respectively sent to the processing roller row 5. After the processing is completed, the precipitation surfaces of the TPU surface layer 1 and the TPU bottom layer 2 are obtained. Then, the precipitation surfaces 3 of the TPU surface layer 1 and the TPU bottom layer 2 are brought close to each other, and the precipitation surfaces 3 of the TPU surface layer 1 and the TPU bottom layer 2 are passed through the intermediate heating roller group 8. After being heated by the intermediate heating roller group 8, they are sent to the hot pressing molding machine 9 to complete the integrated hot pressing molding to obtain the TPU floor cloth 10; When processing the TPU floor cloth 10, the TPU surface layer 1 and the TPU bottom layer 2 are processed independently. Since the melting point of the TPU main material is greater than the melting point of the PBS ingredient, the bottom of the roller row 5 is heated and the top is cooled by processing, and the temperature is controlled to exceed the melting critical point of the PBS ingredient and be lower than the melting critical point of the TPU main material; the TPU surface layer 1 and the TPU bottom layer 2 form a PBS precipitation layer on one side of the TPU surface layer 1 and the TPU bottom layer 2 through flow penetration, and the PBS precipitation layer of the TPU surface layer 1 and the TPU bottom layer 2 is formed with the TPU main material. The staggered and fused bonding surface can avoid the separation of the precipitation layer; then, the heating temperature of the middle heating roller group 8 is controlled, and the PBS precipitation layer is heated and melted for the second time by the middle heating roller group 8, so that the PBS precipitation layer can be plasticized. Since the PBS precipitation layer is in a molten state, the TPU surface layer 1 and the TPU bottom layer 2 are then sent to the hot pressing molding machine 9 to complete the integrated hot pressing molding, so that the two groups of PBS precipitation layers are hot-pressed and combined into one, so that the TPU surface layer 1 and the TPU bottom layer 2 form an anti-stripping TPU floor cloth 10.

[0019] The processing roller row 5 includes 5 to 8 groups of precipitation rollers 6, and the output end of the precipitation rollers 6 is provided with 3 to 5 groups of cooling rollers 7; the upper roller of the precipitation rollers 6 is a cold roller, and the lower roller of the precipitation rollers 6 is a temperature-controlled heating roller, and the heating temperature of the temperature-controlled heating roller is 110 to 115°C, and the upper roller and the lower roller of the cooling roller 7 are both cold rollers; the intermediate heating roller group 8 is composed of a plurality of temperature-controlled heating rollers; when the processing roller row 5 is processed, the TPU surface layer 1 or the TPU bottom layer 2 First enter the 5th to 8th group of precipitation rollers 6, and the temperature-controlled heating rollers of the 5th to 8th group of precipitation rollers 6 continuously heat the TPU surface layer 1 or the TPU bottom layer 2, so that the TPU surface layer 1 or the TPU bottom layer 2 close to the lower roller side of the precipitation roller 6 is fully heated, so that the PBS of the TPU surface layer 1 or the TPU bottom layer 2 is precipitated; then, the TPU surface layer 1 or the TPU bottom layer 2 is fully cooled by the 3rd to 5th group of cooling rollers 7, and then rolled; wait for the subsequent integrated hot pressing molding process.

[0020] A mesh cloth 4 is arranged between the TPU surface layer 1 and the TPU bottom layer 2; the mesh cloth 4 is hot-pressed between the TPU surface layer 1 and the TPU bottom layer 2; the mesh cloth 4 is a carbon fiber mesh cloth or a glass fiber mesh cloth, and the TPU main material is fully bound by the precipitation surface 3, thereby reducing the shrinkage rate of the TPU surface layer 1; then, by secondary plasticizing the precipitation surface 3, a structural layer is formed between the TPU surface layer 1 and the TPU bottom layer 2, and the anti-shrinkage ability is further improved; finally, the mesh cloth 4 can further improve the structural support of the precipitation surface 3, and further reduce the shrinkage rate of the TPU floor.

[0021] A method for preparing a TPU floor with a low shrinkage rate is provided, and is used for preparing a TPU floor with a low shrinkage rate. The method comprises preparing a TPU surface layer 1 and a TPU bottom layer 2, and hot pressing the TPU surface layer 1 and the TPU bottom layer 2 to form a TPU floor cloth 10; the TPU surface layer 1 and the TPU bottom layer 2 are prepared in the same manner, and the specific process is as follows: S1: Mixing at room temperature: putting the TPU main material and PBS ingredients into a three-dimensional mixer, and fully mixing the TPU main material and PBS ingredients through the three-dimensional mixer at room temperature to obtain a mixture; S2: Protect the internal mixer. Put the mixture into the internal mixer and introduce the steam system into the internal mixer. Control the steam temperature at 110~115℃ and keep the heating time at 2~2.5min. At this time, control the internal mixer speed at 5~10 rpm. When the mixture is softened, convert the steam heating to external heating of the internal mixer. During the conversion process, the steam heating is continuously reduced and the external heating source is used to supplement the heat source until the internal temperature of the internal mixer is always maintained at 110~115℃. Until the steam heating is completely turned off, then control the external heating source to reduce the internal temperature of the internal mixer to 105~110℃. Then, increase the internal mixer speed to 25~30 rpm. Keep the internal mixer time at 5~8min to complete the internal mixer to obtain the low shrinkage floor rubber. When the internal mixer processes the mixture, high Warm water vapor is directly sprayed on the TPU main material to achieve the purpose of heating. The high-temperature water vapor has strong penetrability and can quickly fill the entire internal mixer. The water vapor has fast heat transfer and can be evenly distributed around the TPU main material. The TPU main material is evenly heated, which can protect the TPU main material and avoid the bursting of the bubble holes of the TPU main material, resulting in the inability to control the shrinkage rate of the TPU floor. In the early stage of the mixture processing, the internal mixer is kept at a low speed, and the high-temperature water vapor is first filled into the internal mixer. At this time, the stirring system of the internal mixer will not mechanically impact the TPU main material. When the TPU main material is fully heated and melted, and the surface humidity of the mixture is maintained, it is converted to an external heating source again, and the surface humidity is used to protect the surface of the mixture. At the same time, the speed of the internal mixer is increased to fully melt the mixture into one, forming a low-shrinkage floor rubber. S3: TPU surface layer 1 and TPU bottom layer 2 are formed, the low shrinkage floor rubber material is fed into an extruder for extrusion and then pressed into a desired thickness and width by a pressing machine to obtain the TPU surface layer 1 and TPU bottom layer 2; S4: Precipitation processing of TPU surface layer 1 and TPU bottom layer 2, sending TPU surface layer 1 and TPU bottom layer 2 to processing roller row 5, completing the precipitation processing of TPU surface layer 1 and TPU bottom layer 2, and then rolling up the processed TPU surface layer 1 and TPU bottom layer 2 to obtain TPU surface layer 1 coil and TPU bottom layer 2 coil; The processing process of the TPU floor cloth 10 is as follows: the TPU surface layer 1 and the TPU bottom layer 2 are simultaneously fed into the heating roller, and the precipitation surface 3 of the TPU surface layer 1 and the TPU bottom layer 2 is processed by the heating roller to make the precipitation surface 3 in a semi-molten state. Then, the TPU surface layer 1 and the TPU bottom layer 2 are fed into the hot pressing molding machine 9, and the semi-molten precipitation surface 3 of the TPU surface layer 1 and the TPU bottom layer 2 is hot-pressed by the hot pressing molding machine 9, and then the TPU floor cloth 10 is obtained by cooling, cutting and printing.

[0022] Embodiment 2: The low shrinkage TPU floor of the present invention comprises a TPU surface layer 1 and a TPU bottom layer 2, wherein the TPU surface layer 1 and the TPU bottom layer 2 comprise a TPU main material and a PBS ingredient, wherein the TPU main material components are as follows: 40kg TPU polyurethane, 30kg 60C halogen-free flame retardant, 28kg H-AL aluminum hydroxide, 5.5kg halogen-free aluminum flame retardant, 1kg PE compatibilizer, 0.9kg stearic lubricant, 1.3kg polypropylene lubricant, 1.3kg silicone lubricant and 0.15kg 316A lubricant; when the TPU surface layer and TPU bottom layer are made of all TPU main materials, a 2.48mm TPU floor cloth is prepared, and the shrinkage rate of the TPU floor cloth is tested. During the test, multiple batches of samples are cut and tested by constant temperature heating equipment (constant temperature 80℃, continuous heating for 6h). The average lateral change rate is 0.26%, and the average longitudinal change rate is 0.27%; the shrinkage rate is at the critical value of excellent products; then, keep the TPU main material unchanged and put in 22kg PBS particles were added to prepare the TPU surface layer, and the average lateral change rate was 0.09%, and the average longitudinal change rate was 0.11%; then, the TPU main material was kept unchanged, and 45kg of PBS particles were added to prepare the TPU bottom layer, and the average lateral change rate was 0.041%, and the average longitudinal change rate was 0.045%; and according to the above TPU floor preparation method, a TPU floor cloth was prepared, and the thickness of the TPU floor cloth was 2.48mm; and the TPU floor cloth was sampled The sampled TPU floor cloth was sent to a constant temperature heating device (constant temperature 80°C, continuous heating for 6 hours) for testing, and the lateral change rate of the sampled TPU floor cloth was 0.06%, and the longitudinal change rate was 0.05%; the gram weight of the TPU floor cloth was 3.434g, which met the technical requirement of less than 3.5g; the Shore hardness was 88, the tensile strength was 8.56Mpa, the elongation at break was 93.8%, the tear strength was 74.916kN / m, the oxygen index was 31.5%, and the flexibility was crack-free; the above indicators all met the technical requirements.

[0023] The above embodiments are only preferred implementations of the present invention, so any equivalent changes or modifications made according to the structures, features and principles described in the scope of application of the present invention are included in the scope of application of the present invention.

Claims

1. A low shrinkage TPU floor, characterized by: include TPU surface layer, the components of the TPU surface layer include TPU main material and PBS ingredients, and the content of PBS ingredients in the TPU surface layer is 20-25%; A TPU bottom layer, wherein the components of the TPU bottom layer include a TPU main material and a PBS ingredient, and the content of the PBS ingredient in the TPU bottom layer is 40-45%; The thickness ratio of the TPU surface layer to the TPU bottom layer is 3:2; the TPU surface layer and the TPU bottom layer are integrally formed by a hot pressing molding machine; Before the TPU surface layer and the TPU bottom layer are hot-pressed, the PBS precipitation processing of the TPU surface layer and the TPU bottom layer is first completed. During the processing, the TPU surface layer and the TPU bottom layer are respectively sent to the processing roller row. After the processing is completed, the precipitation surfaces of the TPU surface layer and the TPU bottom layer are obtained. Then, the precipitation surfaces of the TPU surface layer and the TPU bottom layer are brought close to each other, and the precipitation surfaces of the TPU surface layer and the TPU bottom layer are passed through an intermediate heating roller group. After being heated by the intermediate heating roller group, they are sent to a hot pressing molding machine to complete integrated hot pressing molding to obtain a TPU floor cloth.

2. The low shrinkage TPU floor according to claim 1, characterized in that: The processing roller row includes 5 to 8 groups of precipitation rollers, and 3 to 5 groups of cooling rollers are arranged at the output end of the precipitation rollers; the upper roller of the precipitation roller pair is a cold roller, and the lower roller of the precipitation roller pair is a temperature-controlled heating roller. The heating temperature of the temperature-controlled heating roller is 110 to 115°C, and the upper roller and the lower roller of the cooling roller pair are both cold rollers; the intermediate heating roller group is composed of multiple temperature-controlled heating rollers.

3. The low shrinkage TPU floor according to claim 1, characterized in that: A mesh cloth is arranged between the TPU surface layer and the TPU bottom layer; the mesh cloth is heat-pressed between the TPU surface layer and the TPU bottom layer.

4. The low shrinkage TPU floor according to claim 3, characterized in that: The mesh cloth is a carbon fiber mesh cloth or a glass fiber mesh cloth; the thickness of the mesh cloth is 1 / 3 to 2 / 3 of the thickness of the precipitation surface.

5. A method for preparing a TPU floor with a low shrinkage rate, used for preparing the TPU floor with a low shrinkage rate as claimed in any one of claims 1 to 4, characterized in that: The method comprises preparing a TPU surface layer and a TPU bottom layer, and hot pressing the TPU surface layer and the TPU bottom layer to form a TPU floor cloth; the TPU surface layer and the TPU bottom layer are prepared in the same manner, and the specific process is as follows: S1: Mixing at room temperature: fully mixing the TPU main material and the PBS ingredients at room temperature to obtain a mixture; S2: Protect the internal mixer, put the mixture into the internal mixer, and introduce the steam system into the internal mixer, control the steam temperature to 110~115℃, and keep the heating time for 2~2.5min; at this time, the internal mixer is in a low speed state; when the mixture is softened, convert the steam heating to the external heating of the internal mixer. During the conversion process, the steam heating is continuously reduced, and the external heating source is used to supplement the heat source until the internal temperature of the internal mixer is always maintained at 110~115℃; until the steam heating is completely turned off, then control the external heating source to reduce the internal temperature of the internal mixer to 105~110℃; then control the internal mixer speed to enter a high speed state; keep the internal mixing time for 5~8min, and complete the internal mixing to obtain a low shrinkage floor rubber compound; S3: TPU surface layer and TPU bottom layer are formed, the low shrinkage floor rubber material is fed into the extruder for extrusion and then pressed into the required thickness and width by the pressing machine to obtain the TPU surface layer and TPU bottom layer; S4: TPU surface layer and TPU bottom layer precipitation processing, the TPU surface layer and TPU bottom layer are sent to the processing roller row to complete the TPU surface layer and TPU bottom layer precipitation surface processing, and then the processed TPU surface layer and TPU bottom layer are rolled to obtain TPU surface layer coils and TPU bottom layer coils; The processing process of the TPU floor cloth is as follows: the TPU surface layer and the TPU bottom layer are simultaneously fed into a heating roller, the precipitation surfaces of the TPU surface layer and the TPU bottom layer are processed by the heating roller to make the precipitation surfaces in a semi-molten state, then the TPU surface layer and the TPU bottom layer are fed into a hot pressing molding machine, the semi-molten precipitation surfaces of the TPU surface layer and the TPU bottom layer are hot pressed by the hot pressing molding machine, and then the TPU floor cloth is obtained by cooling, cutting and printing.

6. The method for preparing a low shrinkage TPU floor according to claim 5, characterized in that: The room temperature mixing is specifically as follows: the TPU main material and the PBS ingredients are put into a three-dimensional mixer, and the TPU main material and the PBS ingredients are fully mixed by the three-dimensional mixer at room temperature to obtain a mixture.

7. The method for preparing a low shrinkage TPU floor according to claim 5, characterized in that: When the internal mixer is in a low speed state, the internal mixer speed is 5 to 10 rpm; when the internal mixer speed enters a high speed state, the internal mixer speed is 25 to 30 rpm.

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