Polypropylene-based composite floor and preparation method thereof

Abstract

The invention relates to a polypropylene-based composite floor and a preparation method thereof, a polypropylene base material layer is a double-layer structure formed by a co-extrusion process, the polypropylene base material layer comprises a lower layer which is a semi-hard polypropylene base layer, and the semi-hard polypropylene base layer comprises 60-75wt% of stone powder; the upper layer is a maleic anhydride modified polypropylene bonding layer; the decorative layer is formed on the surface of the maleic anhydride modified polypropylene bonding layer through water-based ink digital printing; the polypropylene wear-resistant layer is bonded with the decorative layer through a PUR (Polyurethane) adhesive horizontal bonding process; the thickness of the wear-resistant layer is 0.15 mm to 0.5 mm; and the polypropylene balance layer is arranged below the polypropylene base material layer and is used for balancing stress in the hot pressing process. According to the invention, the maleic anhydride modified polypropylene bonding layer is co-extruded on the polypropylene base material, so that normal digital printing and ink jet of a common polypropylene plate can be realized, the material types of the digital printing floor are expanded, and the requirements of different application environments are met.

Description

Technical Field

[0001] The present invention relates to the technical field, and specifically to a polypropylene-based composite floor and a preparation method thereof. Background Art

[0002] Due to characteristics such as light weight, environmental protection, and corrosion resistance, polypropylene sheets are widely used in the field of decorative materials. However, in the prior art, the surface polarity of ordinary polypropylene sheets is weak and the surface energy is low, resulting in insufficient interfacial bonding force with digital printing ink, making it difficult to directly perform high-precision digital printing patterns. Especially when realizing complex textures such as wood grain and stone grain, there are significant technical obstacles.

[0003] Currently in the industry, to endow the floor with an uneven wood grain effect, methods such as ink stacking molding or mechanical planing processing are mostly used. However, the ink stacking process needs to form a three-dimensional texture by layer-by-layer stacking. This method not only consumes a large amount of ink materials, resulting in increased costs, but also causes problems such as blurred pattern edges and decreased detail clarity due to multi-layer stacking. At the same time, the too-thick ink layer is prone to chipping defects during later grooving processing and cannot form a chamfer shape with aesthetic value, seriously affecting the appearance quality of the product. The mechanical planing method has technical bottlenecks such as difficult control of processing accuracy, large equipment loss, and complex process, and it is difficult to achieve fine texture reproduction.

[0004] It should be noted that in the prior art, even by adding high-hardness wear-resistant fillers (such as alumina, silicon carbide, etc.) to the ink in an attempt to improve surface wear resistance, due to the insufficient bonding strength between the ink layer and the substrate and the stress concentration effect, its wear resistance is still limited within 1000 revolutions and cannot meet the requirements of high-intensity use scenarios. The above technical defects seriously restrict the application and promotion of polypropylene-based digital printing floors in the high-end decoration field. Summary of the Invention

[0005] Based on this, it is necessary to provide a polypropylene-based composite floor and a preparation method thereof, which can achieve the coordinated improvement of high-precision digital printing, fine presentation of three-dimensional texture, excellent machinability, and wear resistance while ensuring the characteristics of the substrate.

[0006] To achieve the above object, the present invention provides a technical solution:

[0007] A polypropylene-based composite floor, which sequentially includes from top to bottom:

[0008] A polypropylene substrate layer, which is a double-layer structure formed by a co-extrusion process, including:

[0009] The upper layer is a maleic anhydride-modified polypropylene bonding layer;

[0010] The lower layer is a semi-rigid polypropylene base layer, and the semi-rigid polypropylene base layer contains 60wt.% - 75wt.% stone powder;

[0011] A decorative layer, which is formed by digital printing of water-based ink and is disposed on the surface of the maleic anhydride modified polypropylene adhesive layer;

[0012] A polypropylene wear-resistant layer, which is bonded to the decorative layer by glue; the thickness of the polypropylene wear-resistant layer is 0.15 mm to 0.5 mm;

[0013] A polypropylene balancing layer is disposed below the polypropylene base material layer and is used to balance the stress during the hot pressing process.

[0014] The polypropylene-based composite floor has concave and convex patterns formed by a hot pressing process.

[0015] The decorative layer is obtained by digital printing of water-based ink and is disposed on the surface of the maleic anhydride modified polypropylene adhesive layer of the polypropylene base material layer.

[0016] The technical solution of this application realizes normal digital printing and inkjet of ordinary polypropylene sheets by setting a maleic anhydride modified polypropylene adhesive layer, expands the material types of digital printing floors, meets the requirements of different application environments, and some finished product pictures of digital printing floors are as Figure 1 shown.

[0017] Further, the water-based ink required for printing the decorative layer is specifically UV ink, and the main components are acrylic resin and photoinitiator.

[0018] In the prior art, general digital printing forms concave and convex effects through directional multi-layer stacking of paint. This process has obvious concave and convex textures and poor wear resistance, which is not as good as the hot pressing process of the present invention.

[0019] The polypropylene-based composite floor has concave and convex patterns formed by a hot pressing process.

[0020] The pattern is obtained by deepening the polypropylene wear-resistant layer, a certain amount of polyurethane hot melt adhesive and the decorative layer synchronously through hot pressing on the basis of the pattern of water-based ink digital printing; a technical effect similar to the concave and convex effect achieved by ink stacking in the prior art can be obtained.

[0021] In some embodiments, before the polypropylene wear-resistant layer is bonded to the decorative layer, the surfaces are both corona-treated.

[0022] Specifically, corona treatment is a key pretreatment step before the polypropylene wear-resistant layer is bonded to the decorative layer. By improving the surface energy, introducing polar groups, cleaning the surface and optimizing the microstructure, the interlayer bonding strength and durability are significantly enhanced. This technology not only makes up for the non-polar defect of polypropylene itself, but also provides a process basis for the reliable composite of complex floor structures.

[0023] In some of these embodiments, the glue includes PUR glue. Specifically, PUR (Polyurethane Reactive) is a high-performance adhesive. In some of these embodiments, the thickness of the semi-rigid polypropylene base layer is 2.0 mm to 7.0 mm;

[0024] The thickness of the maleic anhydride-modified polypropylene bonding layer is 0.05 mm to 0.12 mm;

[0025] The thickness of the polypropylene balancing layer is 0.15 mm to 0.35 mm;

[0026] The thickness of the wear-resistant layer is preferably 0.3 mm to 0.5 mm. The thickness of the PUR glue is about 0.05 mm.

[0027] In some of these embodiments, the stone powder includes at least one of calcium carbonate powder, silica powder, alumina powder, aluminum hydroxide powder, magnesium hydroxide powder, and montmorillonite powder. The stone powder is mainly used as a filler, mainly playing roles such as reducing costs, improving processing performance, and enhancing dimensional stability. More specifically, the particle size of the stone powder is 400 - 800 mesh.

[0028] In some of these embodiments, in the maleic anhydride-modified polypropylene bonding layer, the mass ratio of maleic anhydride added is 1% - 2% of the polypropylene. The reason for using maleic anhydride to modify the polypropylene bonding layer is that the maleic anhydride-modified polypropylene bonding layer significantly improves the interfacial bonding performance and compatibility of the polypropylene through chemical grafting of polar groups, and at the same time enhances the overall performance of the composite material as an efficient coupling agent. This modification technology plays a key role in floor manufacturing for optimizing interlayer bonding, extending service life, and achieving multi-functional design.

[0029] The present invention also provides a method for preparing a polypropylene-based composite floor, including the steps:

[0030] S100. Prepare a polypropylene base material layer through a co-extrusion process, wherein:

[0031] The lower layer is a semi-rigid polypropylene base layer containing 60% - 75% stone powder;

[0032] The upper layer is a maleic anhydride-modified polypropylene bonding layer.

[0033] S200. On the surface of the maleic anhydride-modified polypropylene bonding layer, use water-based ink for digital printing of pattern patterns to form a decorative layer.

[0034] In some of these embodiments, apply UV clear varnish for pattern alignment printing at the pattern patterns, and cure with a curing energy of 150 mj / cm 2 ~200 mj / cm 2 for curing.

[0035] S300. Corona-treat the surface of the decorative layer and the surface of the polypropylene wear-resistant layer.

[0036] In some embodiments, the dyne value of the corona treatment on the surface of the decorative layer is above 34;

[0037] The dyne value of the corona treatment on the polypropylene wear-resistant layer is above 36.

[0038] This is because the surface of the decorative layer is a printed ink layer, and it doesn't have a very high requirement for the dyne value itself. While the polypropylene wear-resistant layer is made of PP (polypropylene), and it has a relatively high requirement for the dyne value.

[0039] S400. Roller coat PUR glue on the surface of the decorative layer through a flat laminating process and laminate it with the polypropylene wear-resistant layer.

[0040] In some embodiments, the dosage of PUR glue is 80 g / m 2 ~100 g / m 2 .

[0041] S500. Thermally press the laminated board and the polypropylene balance layer through a flat vulcanizing machine, and set a polypropylene balance layer below the polypropylene base layer.

[0042] Specifically, by setting the balance layer, the problem of dimensional deformation can be solved. At the same time, the thermo-pressing process can also further perform secondary shaping on the internal molecular structure of the product, and can also further improve its flatness and stability.

[0043] More specifically, thermo-pressing can form a synchronous pattern matching effect (i.e., the concave-convex patterns and the pattern textures correspond one by one), or a non-pattern matching effect. It can also form various different texture effects such as cloth texture, stone texture, and crystal texture.

[0044] In some embodiments, the pressure of thermo-pressing is 10 MPa to 15 MPa;

[0045] The temperature of thermo-pressing is 150 °C to 180 °C;

[0046] The time of thermo-pressing is 30 s to 60 s.

[0047] Specifically, if the thermo-pressing temperature is too low or the time is too short, the wear-resistant layer cannot be softened and the embossing cannot be formed. If the temperature is too high or the time is too long, the base material will deform and the patterns on the decorative layer will deform.

[0048] S600. Successively perform UV roller coating, tempering, punching, film laminating, grooving, and chamfering on the thermo-pressed board to obtain a propylene-based composite floor.

[0049] In some of these embodiments, surface UV roller coating uses a transparent UV topcoat, and the roller coating amount of the UV topcoat is 15 g / m 2 ~25 g / m 2 , and the curing energy is 500 mj / cm 2 ~1000 mj / cm 2 ;

[0050] The tempering temperature is 180 °C, and the tempering time is 3 min to 5 min;

[0051] For film pasting, a 1 mm 10-fold foamed PP film is used and pasted by an AB glue roller coating process; specifically, the foamed PP film is also called IXPP, which is light in weight, has good sound insulation effect and low cost. Here, 10-fold refers to the magnification of the foamed PP film. In some embodiments, 3-fold, 5-fold, 7.5-fold, 10-fold and 15-fold foamed PP films can also be used.

[0052] More specifically, AB glue refers to two-component polyurethane glue. The main component of agent A is polyurethane polyol, and the main component of agent B is isocyanate group. The two are mixed and reacted in proportion to form a high-strength and wear-resistant adhesive, A:B = 1:(1~5); preferably, the ratio is 1:4.

[0053] The depth of the grooving and chamfering is 0.2 mm to 0.4 mm, and the width of the grooving and chamfering is 0.5 mm to 2 mm.

[0054] In some of these embodiments, the bonding strength of the polypropylene wear-resistant layer > 60 N / 50 mm; the shrinkage rate of the polypropylene floor under high-temperature aging (80 °C * 6 h) < 0.1%, the warpage change value is less than 1 mm, and the wear-resistant rotation speed > 5000 revolutions.

[0055] Advantages of the present invention:

[0056] 1. By co-extruding a maleic anhydride-modified polypropylene bonding layer on the polypropylene substrate, normal digital printing and inkjet printing on ordinary polypropylene sheets can be realized, expanding the types of materials for digital printing floors and meeting the needs of different application environments;

[0057] 2. Water-based ink is used for digital printing. Compared with oil-based ink, it has a larger surface energy and is easier to bond with glue. At the same time, the surface is first subjected to corona treatment to further increase the surface energy, so as to achieve good bonding between the PUR glue and the wear-resistant layer. The peel strength between the wear-resistant layer and the substrate can reach 60 N / 50 mm, improving the aging resistance and reliability of the product;

[0058] 3. By laminating a layer of polypropylene wear-resistant layer on the surface of the printing layer, not only can normal grooving and chamfering effects be achieved as with traditional floors, but wear-resistant layers of different thicknesses can also be selected according to the requirements of wear resistance revolutions, without affecting the clarity of the printed patterns, improving the wear resistance and aesthetics of the floor. After testing, the wear resistance revolutions of a 0.3mm polypropylene wear-resistant layer can reach 6,000 revolutions, and those of a 0.5mm polypropylene wear-resistant layer can reach 10,000 revolutions;

[0059] 4. Compared with the methods of ink stacking or planing, the hot pressing method adopted in the present invention can not only achieve a good surface embossing effect, but also improve the flatness and dimensional stability of the product. The process of hot pressing patterns: higher precision, lower cost, and more mature technology; Description of the Drawings

[0060] Figure 1 It is a finished product diagram of some digital printing floors;

[0061] Figure 2 It is an effect diagram of the concave-convex patterns of the polypropylene-based composite floor in some embodiments;

[0062] Figure 3 It is a finished product diagram of the common processing chamfering method in the prior art. Detailed Embodiments

[0064] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0065] In the embodiments, unless otherwise specified, the test methods used are all conventional methods, and the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0066] In the embodiments

[0067] The polypropylene base material layer contains the following components: 65-75 parts of stone powder, 15-25 parts of polypropylene resin, 1-5 parts of PE resin, 1-5 parts of toughening agent, 0.5-1 part of stabilizer, 0.2-0.5 part of compatibilizer, 0.02-0.05 part of antioxidant, and 0.2-1 part of lubricant.

[0068] The polypropylene wear-resistant layer is made of high-transparency and high-wear-resistant modified polypropylene resin.

[0069] The PUR glue is a commercially available product.

[0070] In terms of the materials of the polypropylene wear-resistant layer and PUR glue, the main component of the polypropylene wear-resistant layer is polypropylene resin, which does not contain inorganic fillers and pigments and has a very high transparency. The PUR glue is also a transparent material. After being melted, it is coated on the surface of the decorative layer in a thin layer (with a thickness of about 0.02 - 0.05 mm), which does not affect the transparency of the decorative layer and will not affect the visibility of the decorative layer formed by water-based ink.

[0071] The following further illustrates the present invention in conjunction with embodiments, but is not limited thereto.

[0072] Embodiment 1

[0073] A preparation method of a polypropylene-based composite floor of the present invention includes the following steps:

[0074] S100. Extrude a two-layer polypropylene substrate through a co-extrusion process. The lower layer is a semi-rigid polypropylene base layer containing 65% stone powder with a thickness of 2.0 mm, and the upper layer is a maleic anhydride-modified polypropylene bonding layer with a thickness of 0.1 mm;

[0075] S200. Perform digital printing above the polypropylene bonding layer to form a decorative layer using water-based ink;

[0076] S201. Perform digital printing above the polypropylene bonding layer to form wood grain, stone grain or personalized customized pattern;

[0077] S202. Print and cure UV varnish on the pattern in registration. Use a curing energy of 170 mj / cm 2 for curing.

[0078] S300. Perform corona treatment on the surface of the decorative layer and the polypropylene wear-resistant layer;

[0079] S301. Perform corona treatment on the surface of the decorative layer to increase the surface energy to 36 dyn / cm;

[0080] S302. Perform corona treatment on the polypropylene wear-resistant layer to increase the surface energy to 38 dyn / cm;

[0081] S400. Roll coat PUR glue on the surface of the decorative layer through a flat laminating process, and then laminate it with a 0.3-mm polypropylene wear-resistant layer. The glue consumption is 80 g / m 2 ;

[0082] S500. Place the board and the polypropylene balance layer in a flat vulcanizing machine for hot pressing and laminating. The pressure is 13 MPa, the temperature is 160 °C, and the time is 40 s; the thickness of the balance layer is 0.15 mm.

[0083] S600. Perform surface UV roll coating, tempering, punching, film laminating, grooving and chamfering treatments to obtain the polypropylene-based composite floor.

[0084] The surface is roll-coated with transparent UV topcoat, and the coating amount is 20 g / m 2 , and the curing energy is 600 mj / cm 2 ;

[0085] The tempering temperature is 80 °C and the time is 3 min;

[0086] The punching size is 1220×180 mm;

[0087] For film laminating, 1 mm 10-fold foamed PP film is used and laminated by AB glue roll-coating process. AB glue refers to two-component polyurethane glue. The main component of agent A is polyurethane polyol, and the main component of agent B is isocyanate group. The two are mixed and reacted in proportion to form a high-strength and wear-resistant adhesive, A:B = 1:4.

[0088] The grooving chamfer depth is 0.2 mm and the width is 0.6 mm.

[0089] Among them, the product drawing of the polypropylene-based composite floor of the present application is as Figure 1 shown.

[0090] The rendering of the concave-convex texture of the polypropylene-based composite floor of the present application is as Figure 2 shown.

[0091] In addition, the present invention has found through research that when the thickness of the polypropylene wear-resistant layer ≥ 0.3 mm, a micro-chamfer effect can be achieved.

[0092] As Figure 3 shown, in the current industry, usually, the method of ink stacking molding or mechanical planing processing on the surface of the polypropylene wear-resistant layer is adopted to achieve the concave-convex wood grain imitation effect on the surface of the polypropylene wear-resistant layer. However, because the ink (UV paint) is relatively hard and the stacking is excessive, even if the thickness of the ink (UV paint) is increased, the micro-chamfer effect on the surface of the polypropylene wear-resistant layer cannot be achieved.

[0093] Example 2

[0094] Another preparation method of the polypropylene-based composite floor of the present invention includes the following steps:

[0095] S100. Extrude a two-layer polypropylene substrate through a co-extrusion process. The lower layer is a semi-rigid polypropylene base layer containing 75% stone powder with a thickness of 6.0 mm, and the upper layer is a maleic anhydride-modified polypropylene bonding layer with a thickness of 0.12 mm;

[0096] S200. Perform digital printing above the polypropylene bonding layer and use water-based oil to form a decorative layer;

[0097] S201. Perform digital printing above the polypropylene bonding layer to form a wood grain pattern;

[0098] S202. Print UV varnish on the pattern at the flower alignment, and cure it with a curing energy of 180 mj / cm 2 .

[0099] S300. Corona-treat the surface of the decorative layer and the polypropylene wear-resistant layer;

[0100] S301. Corona-treat the surface of the decorative layer to increase the surface energy to 38 dyn / cm;

[0101] S302. Corona-treat the polypropylene wear-resistant layer to increase the surface energy to 38 dyn / cm;

[0102] S400. Roll coat PUR glue on the surface of the decorative layer through the flat laminating process, and then laminate it with a 0.5-mm polypropylene wear-resistant layer. The glue consumption is 90 g / m 2 ;

[0103] S500. Place the board and the polypropylene balance layer in a flat vulcanizing machine for hot pressing and laminating. The pressure is 15 MPa, the temperature is 170 °C, and the time is 45 s; the thickness of the balance layer is 0.3 mm.

[0104] S600. Perform surface UV roll coating, tempering, punching, film laminating, and grooving.

[0105] For surface UV roll coating, use a transparent UV topcoat. The roll coating amount is 20 g / m 2 , and the curing energy is 700 mj / cm 2 ; the tempering temperature is 85 °C, and the time is 3 min;

[0106] The punching size is 1220 × 180 mm;

[0107] Laminating a 1-mm 7.5-fold PP soundproof film on the back of the board with AB glue;

[0108] The chamfer depth of the grooving is 0.4 mm, and the width is 1 mm.

[0109] Comparative Example 1

[0110] Print a decorative layer on the surface of the PP substrate, and then print a structural layer and a wear-resistant layer on the surface of the decorative layer. Stick an IXPP soundproof layer on the substrate surface with AB glue.

[0111] Among them, the structural layer is printed at fixed points with paint and piled up into a three-dimensional pattern.

[0112] Other steps are the same as those in Example 1.

[0113] Comparative Example 2

[0114] The corona treatment was not performed on the surface of the decorative layer and the polypropylene wear-resistant layer in S300, and the other steps were the same as those in Example 1.

[0115] Comparative Example 3

[0116] The base material selected in S100 did not use a maleic anhydride-modified polypropylene adhesive layer, but an ordinary polypropylene adhesive layer, and the other steps were the same as those in Example 1.

[0117] This comparative example will cause the decorative pattern to be unable to be printed on the surface of the base material normally, and the finished board cannot be prepared normally.

[0118] Test Example

[0119] The floors prepared in Examples 1-2 and Comparative Examples 1-2 were selected for performance testing. The test standards and test results are shown in Table 1. Among them, the surface peel strength, high-temperature aging warpage, and wear resistance revolutions are the test standards of SGS testing. The board pattern depth was measured using a depth gauge, and the chamfering effect was measured using a vernier caliper.

[0120] Table 1 SGS Test Result Table

[0121]

[0122] In the table, the surface peel strength refers to the surface peel strength between the polypropylene wear-resistant layer and the decorative layer.

[0123] The high-temperature aging in the table refers to the high-temperature aging at 80°C for 6 hours.

[0124] As can be seen from Table 1, the peel strength between the wear-resistant layer and the base material can reach 60 N / 50 mm, and the shrinkage rate of the polypropylene floor under high-temperature aging (80°C for 6 hours) is <0.1%, improving the aging resistance and reliability of the product.

[0125] The method of hot pressing adopted in the present invention can not only achieve a good surface embossing effect, but also improve the flatness and dimensional stability of the product. The process of hot pressing patterns: higher precision, lower cost, and more mature technology.

[0126] According to the preferred parameter range in the technical solution of the present invention, the qualified rate of the product can be controlled above 95%. Specifically, during the production process, 10,000 square meters of products were produced, and 950 square meters of them were qualified.

[0127] It should be noted that the specific parameters or some reagents in the above embodiments are specific embodiments or preferred embodiments under the concept of the present invention, rather than limitations thereto; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present invention.

Claims

1. A polypropylene-based composite floor, characterized in that: From top to bottom, they include: The polypropylene substrate layer, the double-layer structure formed by the co-extrusion process, comprises: The upper layer is a maleic anhydride modified polypropylene bonding layer; The lower layer is a semi-rigid polypropylene base layer, wherein the semi-rigid polypropylene base layer contains 60wt.% to 75wt.% of stone powder; A decorative layer, the decorative layer is formed by digital printing of water-based ink, and the decorative layer is arranged on the surface of the maleic anhydride modified polypropylene bonding layer; A polypropylene wear-resistant layer, wherein the polypropylene wear-resistant layer is bonded to the decorative layer by glue; the thickness of the polypropylene wear-resistant layer is 0.15 mm to 0.5 mm; The polypropylene balancing layer is arranged below the polypropylene substrate layer and is used to balance the stress during the hot pressing process.

2. The polypropylene-based composite floor according to claim 1, characterized in that: Before the polypropylene wear-resistant layer and the decorative layer are bonded by the polyurethane hot melt adhesive, the surfaces of the polypropylene wear-resistant layer and the decorative layer are subjected to corona treatment; and / or; The glue comprises PUR glue.

3. The polypropylene-based composite floor according to claim 1, characterized in that: The thickness of the semi-rigid polypropylene base layer is 2.0 mm to 7.0 mm; And / or, the thickness of the maleic anhydride modified polypropylene adhesive layer is 0.05 mm to 0.12 mm; And / or, the thickness of the polypropylene balancing layer is 0.15 mm to 0.35 mm; And / or, the wear-resistant layer has a thickness of 0.3 mm to 0.5 mm.

4. The polypropylene-based composite floor according to claim 1, characterized in that: The stone powder includes at least one of calcium carbonate powder, silicon dioxide powder, aluminum oxide powder, aluminum hydroxide powder, magnesium hydroxide powder and montmorillonite powder.

5. The polypropylene-based composite floor according to claim 1, characterized in that: In the maleic anhydride modified polypropylene adhesive layer, the added mass ratio of maleic anhydride is 1% to 2% of the polypropylene.

6. A method for preparing a polypropylene-based composite floor as claimed in any one of claims 1 to 5, characterized in that: Includes steps: S100, preparing a polypropylene substrate layer by a co-extrusion process, wherein: The lower layer is a semi-rigid polypropylene base layer containing 60% to 75% stone powder; The upper layer is a maleic anhydride modified polypropylene bonding layer; S200, digitally printing a decorative layer on the surface of the maleic anhydride modified polypropylene adhesive layer using a water-based ink; S300, performing corona treatment on the surface of the decorative layer and the surface of the polypropylene wear-resistant layer; S400, apply PUR glue roller to the surface of the decorative layer through flat lamination process and press it with the polypropylene wear-resistant layer; S500, hot pressing the laminated sheet and the polypropylene balancing layer through a flat vulcanizer, and arranging a polypropylene balancing layer below the polypropylene substrate layer; S600, the hot-pressed board is sequentially subjected to UV roller coating, tempering, punching, film lamination, grooving and chamfering treatments to obtain a polypropylene-based composite floor.

7. The method for preparing a polypropylene-based composite floor according to claim 6, characterized in that: In step S400, the amount of PUR glue used is 80g / m 2 ~100g / m 2 .

8. The method for preparing a polypropylene-based composite floor according to claim 6, characterized in that: In step S500, the pressure of hot pressing is 10MPa to 15MPa; The temperature of hot pressing is 150℃~180℃; The hot pressing time is 30s to 60s.

9. The method for preparing a polypropylene-based composite floor according to claim 6, characterized in that: In step S600, the surface is UV coated with a transparent UV topcoat, and the coating amount of the UV topcoat is 15g / m 2 ~25g / m 2 , curing energy is 500mj / cm 2 ~1000mj / cm 2 ; And / or, the tempering temperature is 80-90°C and the tempering time is 3-5 minutes; And / or, the film is laminated using a foamed PP film and an AB rubber roller coating process; And / or, the depth of the groove chamfer is 0.2 mm to 0.4 mm, and the width of the groove chamfer is 0.5 mm to 2 mm.

10. The method for preparing a polypropylene-based composite floor according to claim 6, characterized in that: The shrinkage rate of polypropylene flooring after high temperature aging is less than 0.1%, the warping change value is less than 1mm, the surface peeling strength between the polypropylene wear-resistant layer and the decorative layer is greater than 60N / 50mm, and the wear-resistant revolution number is greater than 5000 revolutions.

Images