Non-polyvinyl chloride wood-plastic plate deformation control method and application

Abstract

The present invention relates to the technical field of floor manufacturing, and in particular to a non-polyvinyl chloride wood-plastic plate deformation control method and an application. The method comprises: outputting a non-polyvinyl chloride wood-plastic semi-finished plate from an output port, and pulling the semi-finished plate by means of a traction roller assembly, the direction in which the semi-finished plate is pulled by means of the traction roller assembly not coinciding with the direction of the gravity of the semi-finished plate itself, and the included angle between the two being less than 90 degrees. After the semi-finished plate is output from the output port, the conveying angle thereof is changed, so that the present application effectively overcomes the problems of shrinkage and warping of a traditional plate base material using polyvinyl chloride as a raw material during extrusion, and also unexpectedly improves the mechanical strength, hardness and wear resistance of the plate.

Description

Deformation control method and application of non-PVC wood-plastic board Technical Field

[0001] The present invention relates to the technical field of floor manufacturing, in particular to a deformation control method and application of a non-polyvinyl chloride wood-plastic board. Background Art

[0002] Flooring is an integral part of both indoor and outdoor decoration, providing comfort, aesthetics, thermal insulation, and sound insulation, among other functions. It plays a crucial role in enhancing the quality and comfort of both indoor and outdoor environments. The flooring market is currently experiencing rapid growth, with consumer demand for flooring products increasing year by year. With rising living standards and changing consumer attitudes, higher demands are being placed on flooring types, quality, environmental performance, and decorative effects, further driving the development of the flooring industry. According to market research firms, the flooring market continues to expand, and steady growth is expected in the coming years, with continued demand particularly in the residential and commercial construction sectors.

[0003] Polyvinyl chloride (PVC) wood-based panels are a key material in the flooring industry, highly favored for their outstanding performance and wide range of applications. PVC wood-based panels offer abrasion resistance, water resistance, and corrosion resistance, ensuring a long service life and excellent performance. They are widely used in a variety of applications, including homes, commercial buildings, and outdoor spaces.

[0004] In homes, PVC flooring can mimic the texture and feel of solid wood flooring while also being waterproof and easy to clean, making it a top choice for many home decorators. In commercial buildings, PVC flooring is wear-resistant, non-slip, and easy to install, making it suitable for high-traffic areas such as shopping malls, office buildings, and public spaces. Outdoors, PVC flooring is weather-resistant and waterproof, making it suitable for use in playgrounds, terraces, and gardens.

[0005] For example, patent CN112095967B discloses a multi-layer PVC panel with synchronized patterning and molded rounded edges. The panel comprises a UV paint layer, a PVC wear-resistant layer, a PVC patterned film layer, a PVC substrate, and a PVC base material layer. The panel surface features a synchronized, simulated three-dimensional texture, with rounded edges and a locking structure around the edges, enabling interlocking and splicing between panels. Furthermore, patent CN114953665A discloses a process for preparing PVC flooring. This process involves laminating a PVC substrate layer, a PVC printed layer, and a PVC pre-coated film, and performing a one-step lamination process to produce the finished PVC flooring.

[0006] However, despite its widespread use in the flooring industry, PVC panels also present certain drawbacks and challenges. First, due to the structural characteristics of PVC, its recycling and reuse are difficult, leading to resource waste. Compared to other recyclable materials, PVC has a lower recycling rate, placing a certain strain on the environment. Second, PVC panels release hazardous substances during production, use, and disposal, posing potential risks to the environment and human health. For example, PVC releases harmful substances such as hydrogen chloride and dioxins, which pollute air and water and may cause respiratory diseases and other health issues. This creates pressure and challenges for the flooring industry in terms of both environmental protection and health.

[0007] In order to solve the defects of PVC artificial boards, technicians began to look for non-PVC wood-plastic boards as alternative materials and carried out relevant research and development work. Polyolefin materials (such as polyethylene, polypropylene, etc.) are considered to be a potential alternative to PVC artificial boards. Compared with PVC artificial boards, polyolefin wood-plastic boards have the characteristics of recycling and reuse, which helps to reduce resource waste and environmental pollution. Polyolefin wood-plastic boards can be recycled and reprocessed through physical and chemical methods to make new wood-plastic boards or other plastic products, reducing dependence on and mining of raw materials, while reducing pollution to the environment and waste of resources. This recyclable and reuse feature is in line with the concept of sustainable development and environmental protection, and promotes the green development of the flooring industry.

[0008] For example, patent CN108659333A provides a non-PVC surface covering, comprising a primer layer, an intermediate layer, and a transparent wear-resistant layer. The transparent wear-resistant layer comprises polyolefin, polyolefin elastomer, or polyolefin plastomer, and a processing aid. Furthermore, patent CN111267448A discloses a non-PVC-based 3D printed floor, comprising a non-PVC base layer, a balancing layer, and a solid wood layer. The surface of the solid wood layer is provided with a UV primer layer and a white UV paint layer, and also has a printed pattern layer and a concave-convex effect layer.

[0009] However, research on polyolefin-based wood-plastic panels has revealed that, while polyolefins offer excellent physical properties and chemical stability, they also exhibit high thermal shrinkage, making them susceptible to warping during the panel forming process. Furthermore, compared to PVC-based panels, polyolefins lag behind in wear resistance. Consequently, due to these two drawbacks, non-PVC wood-plastic panels made from polyolefins still face significant obstacles in the flooring market. To overcome these challenges, improvements are needed in the methods and equipment for preparing panels made from polyolefins, thereby enhancing the quality, stability, and environmental friendliness of non-PVC wood-plastic panels.

[0010] Summary of the Invention

[0011] The present invention aims to overcome the defects of the prior art non-PVC wood-plastic board in that the warping rate is high during the molding process, resulting in unevenness and instability of the final floor. Therefore, a deformation control method and application of the non-PVC wood-plastic board are provided to overcome the above-mentioned shortcomings.

[0012] To achieve the above-mentioned purpose, the present invention is implemented through the following technical solutions:

[0013] In a first aspect, the present invention first provides a method for controlling deformation of a polyvinyl chloride wood-plastic board, characterized in that it comprises at least the following steps:

[0014] (S.1) providing an extruder and a die adapted therefor, the die comprising an outlet for discharging a semi-finished sheet; (S.2) providing a set of traction roller assemblies for traction and shaping the semi-finished sheet, the traction inlet of the traction roller assembly being at a lower height than the outlet;

[0015] (S.3) Outputting the non-PVC wood-plastic semi-finished board from the output port, and pulling the semi-finished board by the pulling roller assembly, so that the direction in which the semi-finished board is pulled by the pulling roller assembly does not coincide with the direction of the gravity acting on the semi-finished board itself, and the angle between the two is less than 90 degrees.

[0016] Preferably, the angle between the direction in which the semi-finished plate is pulled by the traction roller assembly and the direction of the gravity acting on the semi-finished plate itself is 30-60°.

[0017] Preferably, the traction roller assembly in step (S.3) includes at least three traction rollers, so that the semi-finished plate is squeezed at least twice by adjacent traction rollers during the process of being pulled by the traction roller assembly, and heat exchange occurs during the process of the semi-finished plate being in contact with the traction rollers, thereby reducing the temperature of the semi-finished plate.

[0018] Preferably, step (S.3) further includes the step of independently adjusting the temperature of each traction roller in the traction roller assembly so that the internal and external temperatures of the semi-finished plate are consistent after it is output from the traction roller assembly.

[0019] Preferably, the temperatures of the pulling rollers in the pulling roller assembly in step (S.3) are increased sequentially along the conveying direction of the semi-finished plate.

[0020] Preferably, the temperature difference between the traction roller for inputting the semi-finished plate and the temperature of the output port in the traction roller assembly is 10-15°C;

[0021] The difference between the temperature of the traction roller for outputting the semi-finished plate in the traction roller assembly and the temperature of the output port is ≤10°C.

[0022] Preferably, after step (S.3) is completed, step (S.4) is further included, which is an intermediate processing step of suspending the semi-finished plate in the air under traction and naturally cooling it under ambient conditions.

[0023] Preferably, after the intermediate processing step is completed, the step of tempering and shaping the semi-finished plate is also included.

[0024] Preferably, the tempering temperature is 10-15° C. higher than the temperature of the semi-finished plate after the intermediate processing step.

[0025] Preferably, in step (S.4), the semi-finished plate is pulled by a set of pulling mechanisms;

[0026] The rotation speed of the traction mechanism is higher than the rotation speed of the traction roller assembly.

[0027] Preferably, the semi-finished board material contains polyolefin, wood powder, stone powder and processing aids.

[0028] Preferably, the polyolefin is any one or more of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-polypropylene copolymer, ethylene-acrylic acid or acrylate copolymer, poly-1-butene, and poly-4-methyl-1-pentene.

[0029] In a second aspect, the present invention further provides the use of the above-mentioned method for controlling deformation of non-PVC wood-plastic board in the preparation of non-PVC wood-plastic board or non-PVC floor.

[0030] Compared with the prior art, this application has the following beneficial effects:

[0031] (1) The present application adjusts the traction conveying angle of the semi-finished board after it is output from the output port, so that the conveying direction of the semi-finished board from the output port to the inlet of the traction roller assembly does not coincide with the direction of the gravity exerted on the semi-finished board itself and the angle between the two is less than 90 degrees, thereby effectively overcoming the shrinkage and warping problems that newly appear during the molding process of non-PVC wood-plastic board;

[0032] (2) The above arrangement unexpectedly improves the mechanical strength, hardness and wear resistance of the plate;

[0033] (3) The non-PVC wood-plastic board produced by the method described in this application effectively improves the qualified rate of the floor, thereby effectively reducing the dependence on and mining of raw materials, while reducing pollution to the environment and waste of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a flow chart of an embodiment of the present invention.

[0035] FIG2 is a schematic diagram of preparing a semi-finished plate using a preparation method in the prior art.

[0036] FIG3 is a schematic diagram of the preparation method of the present invention for preparing a semi-finished plate.

[0037] FIG. 4 is a schematic diagram of preparing a semi-finished plate using a pulling roller assembly comprising two pulling rollers.

[0038] FIG5 is a schematic diagram of preparing a semi-finished plate using a pulling roller assembly comprising four pulling rollers.

[0039] FIG6 is a flow chart of another embodiment of the present invention.

[0040] FIG7 is a schematic diagram of step (S.3) to step (S.5).

[0041] Among them: output port 100, semi-finished plate 200, traction roller assembly 300, traction roller 301, tempering and shaping equipment 400, traction mechanism 500. DETAILED DESCRIPTION

[0042] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below generally represent only a portion of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0043] Example

[0044] As shown in FIG1 , in a first embodiment of the present invention, the present invention first provides a method for controlling deformation of a non-PVC wood-plastic board, which comprises at least the following steps:

[0045] (S.1) providing an extruder and a die adapted thereto, wherein the die comprises an outlet for discharging the semi-finished sheet;

[0046] (S.2) providing a set of traction roller assemblies for traction and shaping of the semi-finished plate, wherein the traction inlet of the traction roller assembly is lower than the outlet;

[0047] (S.3) Outputting a semi-finished board material comprising polyolefin and wood powder from an output port, and pulling the semi-finished board material by a pulling roller assembly, so that the direction in which the semi-finished board material is pulled by the pulling roller assembly does not coincide with the direction of gravity acting on the semi-finished board material itself, and the angle between the two is less than 90 degrees.

[0048] In the prior art, the preparation process of sheet substrates made of polyvinyl chloride (such as SPC substrates and LVT substrates) usually uses polyvinyl chloride as a polymer substrate and adds stone powder thereto. Finally, the desired sheet is obtained through an extrusion process. Since polyvinyl chloride is an amorphous polymer, its volume shrinkage before and after extrusion is relatively low. Traditional polyvinyl chloride substrates do not need to consider too much about the warping caused by volume shrinkage during the preparation process. In addition, polyvinyl chloride has a strong polarity, and the melt viscosity obtained after mixing and melting with stone powder is relatively high. The semi-finished sheet obtained after the melt flows out of the mold and cools has a high hardness. Even under the action of external force, it maintains a strong shape stability and is less likely to warp or deform.

[0049] For these reasons, the current extrusion process for polyvinyl chloride (PVC) sheet materials typically involves melting the material in an extruder, passing it through a horizontally mounted die, and then producing a semi-finished sheet. The sheet is then pulled horizontally into a cooling mechanism for cooling and shaping. However, with increasing environmental protection requirements, upgrading and replacing PVC materials has become urgent. However, the use of conventional extrusion equipment to produce new polyolefin-based sheet materials has encountered unexpected technical challenges. The semi-finished polyolefin sheets produced using conventional extrusion equipment exhibit significant volume shrinkage and severe warping, making them difficult to use in the production of non-PVC wood-plastic panels and non-PVC wood-plastic flooring.

[0050] In response to the above phenomenon, researchers conducted in-depth research and found that the reasons for the serious warping and deformation of non-PVC wood-plastic boards include at least the following: (1) The molecular chain segments of polyolefin materials (any one of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-polypropylene copolymer, ethylene-acrylic acid or acrylate copolymer, poly-1-butene, and poly-4-methyl-1-pentene) are more regular, resulting in their crystallization performance being significantly higher than that of traditional polyvinyl chloride, resulting in volume shrinkage during the crystallization process. (2) The viscosity of the polyolefin melt is low when it is extruded from the mold, and it is easily deformed by external forces (such as traction and gravity). (3) The influence of traction and gravity causes the degree of crystallization of the polyolefin material at different positions to be uneven, further exacerbating the occurrence of warping. In response to the above causes of warping, researchers proposed improvements in several aspects: raw material formulation, preparation and molding process, and molding equipment.

[0051] This application is based on a method for producing non-PVC wood-plastic boards with polyolefin as the main material, and aims to solve or alleviate the serious warping and deformation problems caused by the use of the PVC wood-plastic board preparation method.

[0052] During routine experiments, the applicant unexpectedly discovered that after the polyolefin non-PVC wood-plastic board is extruded, the subsequent drawing and cooling steps have a significant impact on its own crystallization behavior, thereby affecting the deformation resistance of the semi-finished board.

[0053] As shown in FIG2 , the applicant discovered that: after the polyolefin raw materials, wood flour, stone powder and other raw materials are melted and plasticized in the extruder and extruded from the output port 100 of the mold, the melt is affected by gravity, causing the middle part of the semi-finished board 200 to sag. If the semi-finished board 200 is subjected to a horizontal traction force during transportation at this time, the superposition of the two forces in different directions, gravity and traction, will cause the crystallization behavior at the center and the edge of the semi-finished board to be inconsistent, resulting in different crystallinity and crystal size at the center and the edge of the semi-finished board 200, and ultimately causing warping in its width direction. Note: The length direction described in this application is the direction in which the semi-finished board 200 is transported by the traction force, the width direction described in this application is the direction of the surface of the semi-finished board 200 perpendicular to its length direction, and the thickness direction described in this application is the perpendicular direction between the upper and lower planes of the semi-finished board 200.

[0054] As shown in Figure 3, the present application addresses this phenomenon by creatively adjusting the angle between the direction in which the semi-finished sheet 200 is pulled by the pulling roller assembly 300 and the direction of gravity acting on the semi-finished sheet 200 to be less than 90 degrees. This arrangement reduces the effect of gravity on the semi-finished sheet 200 in its thickness direction, making the effect of gravity uniform across its width. This results in more balanced crystallization behavior across its width, effectively reducing warping of the semi-finished sheet 200 in its width direction.

[0055] In addition, through the above-mentioned setting, the resultant force of the semi-finished plate 200 along its length direction is also improved, so that the macromolecules or microcrystals and other structures inside the semi-finished plate are significantly oriented along its length direction, further accelerating the induction effect of external force on the semi-finished plate along its length direction, and ultimately improving the crystallization speed and crystallinity of the semi-finished plate, thereby preventing shrinkage and warping caused by changes in its crystal form during subsequent cooling and storage processes.

[0056] Furthermore, since the macromolecules or microcrystals inside the semi-finished plate 200 are oriented under the induction of external force, their crystal structures are always evenly arranged along the length direction of the semi-finished plate, so the mechanical strength, hardness and wear resistance of the semi-finished plate can be greatly improved.

[0057] However, the direction in which the semi-finished plate 200 is pulled by the traction roller assembly 300 along the output port 100 and the direction of the gravity on the semi-finished plate itself are not necessarily as small as possible. For example, in the extreme case where the two coincide, the resultant force on the semi-finished plate along its length direction is greatly increased, resulting in uneven thickness of the semi-finished plate, which is specifically manifested as the generation of flow lines and wave lines.

[0058] In order to explore the relationship between the traction direction of the traction roller assembly 300 and the warping degree of the semi-finished plate 200 obtained in the final embodiment, the semi-finished plate 200 prepared at different traction angles of the traction roller assembly 300 was tested, and the test results are shown in Table 1 below.

[0059] Table 1

[0060] The test results above demonstrate that changing the angle between the pulling direction of the traction roller assembly 300 and the horizontal plane effectively reduces the effect of gravity on the warpage of the semi-finished sheet 200. When the angle between the pulling direction of the traction roller assembly 300 and the horizontal plane is 0°, the warpage of the semi-finished sheet 200 reaches its maximum, reaching 0.62 mm / m. As the angle between the pulling direction of the traction roller assembly 300 and the horizontal plane increases, the warpage gradually decreases. When the angle between the pulling direction of the traction roller assembly 300 and the horizontal plane is ≥30°, the warpage of the semi-finished sheet 200 can reach a level of less than 0.3 mm / m. However, a larger angle between the outlet and the horizontal plane is not necessarily better. When the angle between the pulling direction of the traction roller assembly 300 and the horizontal plane is 80°, flow lines appear on the surface of the semi-finished sheet 200. When the pulling direction of the traction roller assembly 300 is perpendicular to the horizontal plane (i.e., at an angle of 90°), obvious flow lines are present. Therefore, considering the warping and flow pattern of the semi-finished plate, when the angle between the direction in which the semi-finished plate 200 is pulled by the traction roller assembly 300 and the direction of the gravity on the semi-finished plate 200 itself is 30-60°, the prepared semi-finished plate 200 has the best performance.

[0061] Therefore, in summary, this embodiment effectively overcomes the shrinkage and warping problems that arise during the molding process of non-PVC wood-plastic boards by adjusting the angular relationship between the direction in which the semi-finished board 200 is pulled by the traction roller assembly 300 and the direction of the gravity exerted on the semi-finished board 200 itself, and unexpectedly improves the mechanical strength, hardness and wear resistance of the board.

[0062] As shown in Figure 3, in some preferred embodiments, the traction roller assembly 100 includes at least three traction rollers 301, so that the semi-finished plate 200 is squeezed at least twice by adjacent traction rollers 301 during the process of being pulled by the traction roller assembly 300, and heat exchange occurs during the process of the semi-finished plate and the traction roller exchanging, thereby reducing the temperature of the semi-finished plate.

[0063] To verify the effect of the number of pulling rollers 301 in a pulling roller assembly 300 on the warpage of a semi-finished plate 200, pulling roller assemblies 300 as shown in Figures 4 and 5 were respectively set up. The pulling roller assembly 300 in Figure 4 only includes two pulling rollers 101, so that the semi-finished plate 200 is squeezed once by adjacent pulling rollers 301 during the pulling roller assembly 300. The pulling roller assembly 300 in Figure 5 only includes four pulling rollers 301, so that the semi-finished plate 200 is squeezed three times by adjacent pulling rollers 301 during the pulling roller assembly 300.

[0064] The test results are shown in Table 2 below.

[0065] Table 2

[0066] It can be seen from the above test results that as the number of traction rollers in the traction roller assembly 300 increases, the semi-finished plate 200 is squeezed more times during the traction of the semi-finished plate 200 by the traction roller assembly 300, thereby more effectively releasing the stress inside the semi-finished plate 200 and reducing the degree of warping of the semi-finished plate 200.

[0067] In addition to the angle between the outlet 100 and the horizontal plane regulating the warpage of the semi-finished sheet 200, the applicant has also discovered that the temperature of each pulling roller 301 in the pulling roller assembly 300 plays a secondary role in controlling the deformation of the semi-finished sheet 200. This is because, as the molten material is discharged from the outlet 100 of the mold, the temperature of the surface of the semi-finished sheet 200 rapidly drops, while the middle portion remains at a higher temperature. Consequently, a large temperature difference exists between the inside and outside of the semi-finished sheet 200, causing significant changes in the crystallinity inside and outside the semi-finished sheet 200. Specifically, the polymer crystals on the surface of the semi-finished sheet 200 are smaller in size, while the polymer crystals inside the semi-finished sheet 200 are relatively larger. Furthermore, the sudden drop in temperature on the surface of the semi-finished sheet 200 causes some polymer chains to cool and solidify before they have time to crystallize, resulting in changes in the crystallinity of the polymer inside and outside the semi-finished sheet 200, further affecting the stability of the semi-finished sheet 200.

[0068] To address the above issues, the present application independently adjusts the temperature of each pulling roller 301 in the pulling roller assembly 300, ensuring that the temperature inside and outside the semi-finished sheet 200 is consistent after exiting the pulling roller assembly 300, thereby radically changing the original polymer crystallization process. The applicant has discovered that by gradually increasing the temperature of the pulling rollers 301 in the pulling roller assembly 300, the crystallinity of the polymer inside and outside the semi-finished sheet 200 can be increased. This allows for precise control of the polymer crystallization process, ensuring uniform crystallization during transport, thereby improving the quality and consistency of the finished product and reducing material non-uniformity. This helps to increase the strength and stiffness of the semi-finished sheet 200, making it more suitable for specific application requirements. Furthermore, by gradually increasing the temperature of the pulling rollers 301 in the pulling roller assembly 300, the semi-finished sheet 200 can be subjected to an annealing step, thereby reducing residual stress in the semi-finished sheet 200. The principle behind this is that temperature changes can induce polymer molecules to rearrange, reducing residual stress in the sheet, and improving the sheet's stability and durability.

[0069] In some preferred conditions of this embodiment, the temperature difference between the pulling roller 301 in the pulling roller assembly 300 for inputting the semi-finished sheet 200 and the temperature of the outlet 301 can be 10-15°C, while the temperature difference between the pulling roller 301 in the pulling roller assembly 300 for outputting the semi-finished sheet 200 and the temperature of the outlet 100 can be ≤10°C. This setting can ensure that the temperature of the pulling roller 301 in the pulling roller assembly 300 is closer to the temperature of the semi-finished sheet 200 output from the outlet 100, effectively avoiding the phenomenon of uneven crystallization caused by rapid cooling of the semi-finished sheet 200, thereby further improving the stability of the semi-finished sheet 200 and reducing its warpage.

[0070] In order to explore the relationship between the temperature of the pulling roller assembly 300 and the warping degree of the semi-finished plate 200 finally obtained, the temperature of each pulling roller 301 in the pulling roller assembly 300 is set separately in this embodiment, and the semi-finished plate 200 prepared is tested, wherein the pulling rollers 301 in the pulling roller assembly 300 are marked as pulling roller No. 1, pulling roller No. 2, and pulling roller No. 3 along the conveying direction of the semi-finished plate 200, and the test results are shown in Table 3 below.

[0071] Table 3

[0072] It can be seen from the above test results that as the temperature of each pulling roller 301 in the pulling roller assembly 300 changes, the warping of the semi-finished plate 200 obtained in the end will also be adjusted accordingly.

[0073] As shown in Figures 6 and 7, in some preferred embodiments, after step (S.3), a further step (S.4) is included, wherein the semi-finished plate is suspended in mid-air under the traction of a set of traction mechanisms 500 and naturally cooled under ambient conditions. The rotational speed of the traction mechanism is higher than the rotational speed of the traction roller assembly.

[0074] Furthermore, after the intermediate processing step, a further step (i.e., step (S.5) in FIG. 6 ) is included in which the semi-finished sheet material is subjected to tempering and shaping equipment 400 for tempering and shaping. This further eliminates residual stress within the semi-finished sheet material, thereby further reducing the warpage of the semi-finished sheet material 200 after the tempering and shaping treatment. However, the tempering and shaping temperature also has a certain relationship with the warpage of the semi-finished sheet material 200. The applicant has found that the tempering and shaping temperature has a significant effect on the release of residual stress only when it is within a certain range. Excessively low or high temperatures have little effect on the improvement of warpage and may even have the opposite effect. The relevant test results are shown in Table 4 below.

[0075] Table 4

[0076] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A method for controlling the deformation of non-PVC wood-plastic boards, characterized in that, At least include the following steps: (S.1) Provide an extruder and a mold adapted thereto, the mold comprising an outlet for outputting a semi-finished sheet; (S.2) Provide a set of traction roller assemblies for traction and shaping of the semi-finished sheet, the traction inlet height of the traction roller assemblies being lower than the outlet; (S.3) Output a non-PVC wood-plastic composite semi-finished sheet from the outlet, and traction the semi-finished sheet through the traction roller assemblies, such that the direction in which the semi-finished sheet is tractioned by the traction roller assemblies does not coincide with the direction of the gravity force received by the semi-finished sheet itself and the angle between the two is less than 90 degrees.

2. The non-PVC wood-plastic composite sheet deformation control method according to claim 1, wherein the angle between the direction in which the semi-finished sheet is tractioned by the traction roller assemblies and the direction of the gravity force received by the semi-finished sheet itself is 30-60°.

3. The non-PVC wood-plastic composite sheet deformation control method according to claim 1 or 2, wherein in step (S.3), the traction roller assemblies at least include 3 traction rollers, such that during the process of the semi-finished sheet being tractioned by the traction roller assemblies, it is squeezed at least twice by adjacent traction rollers, and such that heat exchange occurs during the process of the semi-finished sheet being in squeezing contact with the traction rollers, thereby reducing the temperature of the semi-finished sheet.

4. The non-PVC wood-plastic composite sheet deformation control method according to claim 3, wherein step (S.3) further includes a step of independently adjusting the temperature of each traction roller in the traction roller assemblies, such that the internal and external temperatures of the semi-finished sheet are the same after it is output from the traction roller assemblies.

5. The non-PVC wood-plastic composite sheet deformation control method according to claim 4, wherein the temperatures of the traction rollers in the traction roller assemblies in step (S.3) increase sequentially along the conveying direction of the semi-finished sheet.

6. The non-PVC wood-plastic composite sheet deformation control method according to claim 5, wherein the temperature difference between the traction roller for inputting the semi-finished sheet in the traction roller assemblies and the temperature of the outlet is 10-15°C; the temperature difference between the traction roller for outputting the semi-finished sheet in the traction roller assemblies and the temperature of the outlet ≤ 10°C.

7. The non-PVC wood-plastic composite sheet deformation control method according to claim 1, wherein after step (S.3) ends, it further includes step (S.4) of, in a traction state, suspending the semi-finished sheet and naturally cooling it under environmental conditions as an intermediate treatment step.

8. The non-PVC wood-plastic composite sheet deformation control method according to claim 7, wherein after the intermediate treatment step ends, it further includes a step of tempering and shaping the semi-finished sheet.

9. The non-PVC wood-plastic composite sheet deformation control method according to claim 8, wherein the temperature for tempering and shaping is 10-15°C higher than the temperature of the semi-finished sheet after the intermediate treatment step.

10. The non-PVC wood-plastic composite sheet deformation control method according to claim 7 or 8 or 9, wherein in step (S.4), the semi-finished sheet is tractioned by a set of traction mechanisms; The rotational speed of the traction mechanism is higher than that of the traction roller assembly.

11. The method for controlling the deformation of non-PVC wood-plastic boards according to claim 1, wherein The semi-finished board contains polyolefin, wood powder, stone powder and processing aids.

12. The method for controlling the deformation of non-PVC wood-plastic boards according to claim 11, wherein The polyolefin is any one or a combination of polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-acrylic acid or acrylate copolymer, poly-1-butene, poly-4-methyl-1-pentene.

13. The application of the method for controlling the deformation of non-PVC wood-plastic boards according to any one of claims 1-12 in the preparation of non-PVC wood-plastic boards or non-PVC floors.

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