PEVA non-slip mat and preparation method thereof

Abstract

The invention discloses a PEVA non-slip mat and a preparation method thereof, and belongs to the technical field of high polymer material composite products. The non-slip mat is of a two-layer co-extrusion structure and sequentially comprises an EVA non-slip fitting layer and a PE / PP wear-resistant layer from bottom to top. The EVA layer is tightly attached to the surface of furniture by means of the elasticity of the EVA layer, and the PE / PP layer enhances wear resistance and supporting performance by adding PP. And meanwhile, according to the preparation method, the flow velocity of two layers of melts is accurately regulated and controlled by controlling an extrusion kinetic equation, so that the interlayer binding force and the anti-slip performance are synergistically improved, and the problems of poor anti-slip performance and insufficient fitness of an anti-slip mat in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material composite products, in particular to a PEVA anti-slip mat and a preparation method thereof. Background Art

[0002] Anti-slip mats, when used on furniture countertops in daily life, must protect the furniture surface from moisture, dust, and oil. However, conventional anti-slip mats are primarily made of polyethylene (PE) through single-layer tape casting, as in Patent Application No. 2014106387484, or are extruded from a mixture of PE and ethylene-vinyl acetate copolymer (EVA), as in Patent Application No. 2017105693541.

[0003] The study found that the above preparation method has significant defects: on the one hand, whether it is a single-layer PE material or a mixed material of PE and EVA, the anti-slip property of both the front and back sides is poor, and it is easy to move and fall on the surface of furniture when taking and placing items; on the other hand, it is not conformable enough and cannot fit tightly to the uneven structure of the table top, resulting in poor stability in use. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a PEVA anti-slip mat and a preparation method thereof, so as to solve the problems of poor anti-slip properties and insufficient conformability of anti-slip mats in the existing market.

[0005] Based on the above purpose, the present invention provides a PEVA anti-slip mat, which adopts a two-layer co-extrusion structure, which is composed of:

[0006] EVA anti-slip conformable layer, made of EVA, with a thickness of 0.5-1.0mm, accounting for 30%-40% of the total mass;

[0007] This layer uses the polarity of the vinyl acetate group in the EVA molecular chain to form intermolecular forces (such as hydrogen bonds and van der Waals forces) with the furniture surface. At the same time, with the good flexibility and elasticity of EVA, it can adaptively fit the tiny bumps on the tabletop, increasing the actual contact area, thereby improving anti-slip properties and compliance.

[0008] PE / PP wear-resistant layer, made of PE and PP blend, PE content 70%-80%, PP content 20%-30%, thickness 1.0-1.5mm, accounting for 60%-70% of the total mass;

[0009] The addition of PP can improve the rigidity of the material. After blending with PE, it forms a rigid and flexible structure, which not only ensures the supporting strength of the wear-resistant layer, but also provides a stable composite base for the EVA layer.

[0010] At the same time, the present invention also provides a method for preparing the PEVA anti-slip mat, which comprises the following steps:

[0011] Raw material preparation: Mix PE and PP in a mass ratio of 70%-80%:20%-30%, add lubricant and antioxidant, and mix evenly to obtain the PE / PP wear-resistant layer material; mix EVA resin with processing aids to obtain the EVA anti-slip conformable layer material;

[0012] Two-layer co-extrusion molding: Two single-screw extruders are used to plasticize and extrude the PE / PP wear-resistant layer material and the EVA anti-slip conformable layer material respectively, and then compounded through a layer co-extrusion die. The linear speed ratio of the PE / PP layer to the EVA layer is controlled at 0.9-1.0:1.0-1.2;

[0013] Cooling, shaping and post-processing: The anti-slip mat blank is cooled through a three-stage cooling system, and the finished product is obtained through pulling and cutting.

[0014] And in the process of the two-layer co-extrusion molding, the extrusion speed of each layer is determined by the mechanical motion equation Determine, where ν is the extrusion line speed m / min, n is the non-Newtonian index, Q is the melt volume flow rate cm / s; A is the die lip cross-sectional area cm 2 ;η is the melt viscosity Pa·s, τ y is the melt yield stress Pa, L is the length of the straight section of the die lip cm, ΔP is the die head pressure drop MPa, and R is the equivalent radius of the flow channel cm;

[0015] The non-Newtonian index n of the PE / PP layer is 0.35-0.40, and the non-Newtonian index n of the EVA layer is 0.40-0.50.

[0016] The present invention has the following beneficial effects: By optimizing the VA content of the EVA anti-slip conformable layer (18%-30%) and the ratio of the PE / PP wear-resistant layer (70%-80% PE, 20%-30% PP), the anti-slip mat achieves a static friction coefficient of 0.75-0.85 in dry conditions and maintains a coefficient of friction of 0.60-0.70 in wet conditions. This performance is primarily due to the hydrogen bonding between the polar groups of the EVA layer and the contact surface, as well as the surface microstructure formed by controlling the extrusion speed through the equation of mechanical motion, which increases the actual contact area by 30%-50%.

[0017] By controlling the line speed ratio of the two layers to 0.9-1.0:1.0-1.2 and combining it with specific processing aids, the air retention of the anti-slip mat is reduced to ≤4.5%, improving its conformability by over 70%. Furthermore, the interlayer peel strength is ≥2.0N / cm, ensuring long-term non-separation. This is primarily due to the formation of a melt interface diffusion layer (10-20μm) and a crystalline interlocking structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only a part of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0019] Figure 1 The figure shows the product schematic diagram of the anti-skid pad of the embodiment of the present application.

[0020] 1, EVA anti-skid pad layer; 2, PE / PP wear-resistant layer. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present application more clear and obvious, the present application will be further described in detail in combination with specific embodiments.

[0022] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the usual meaning understood by those skilled in the art. The "first", "second" and similar words used in the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent the relative positional relationship, when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0023] The existing anti-skid pad preparation method has significant defects: on the one hand, whether it is a single layer of PE material or a mixed material of PE and EVA, the anti-skid property of the anti-skid pad is poor, and when taking and placing objects, it is easy to move and fall on the surface of furniture; on the other hand, the fit is not enough, and it cannot closely fit the concave-convex structure of the table top, resulting in poor use stability.

[0024] In order to solve the above problems, as shown in Figure 1 The present application provides a PEVA anti-skid pad, which adopts a two-layer co-extrusion structure, from bottom to top in order:

[0025] The EVA anti-skid fit layer is made of EVA, with a thickness of 0.5-1.0mm, accounting for 30%-40% of the total mass;

[0026] This layer uses the polarity of the vinyl acetate group in the EVA molecular chain to form intermolecular forces (such as hydrogen bonds and van der Waals forces) with the furniture surface. At the same time, with the good flexibility and elasticity of EVA, it can adaptively fit the tiny bumps on the tabletop, increasing the actual contact area, thereby improving anti-slip properties and compliance.

[0027] PE / PP wear-resistant layer, made of PE and PP blend, PE content 70%-80%, PP content 20%-30%, thickness 1.0-1.5mm, accounting for 60%-70% of the total mass;

[0028] The addition of PP can improve the rigidity of the material. After blending with PE, it forms a rigid and flexible structure, which not only ensures the supporting strength of the wear-resistant layer, but also provides a stable composite base for the EVA layer.

[0029] At the same time, the present invention also provides a method for preparing the PEVA anti-slip mat, which comprises the following steps:

[0030] Raw material preparation: Mix PE and PP in a mass ratio of 70%-80%:20%-30%, add lubricant and antioxidant, and mix evenly to obtain the PE / PP wear-resistant layer material; mix EVA resin with processing aids to obtain the EVA anti-slip conformable layer material;

[0031] Two-layer co-extrusion molding: Two single-screw extruders are used to plasticize and extrude the PE / PP wear-resistant layer material and the EVA anti-slip conformable layer material respectively, and then compounded through a layer co-extrusion die. The linear speed ratio of the PE / PP layer to the EVA layer is controlled at 0.9-1.0:1.0-1.2;

[0032] Cooling, shaping and post-processing: The anti-slip mat blank is cooled through a three-stage cooling system, and the finished product is obtained through pulling and cutting.

[0033] And in the process of the two-layer co-extrusion molding, the extrusion speed of each layer is determined by the mechanical motion equation Determine, where ν is the extrusion line speed m / min, n is the non-Newtonian index, Q is the melt volume flow rate cm / s; A is the die lip cross-sectional area cm 2 ;η is the melt viscosity Pa·s, τ y is the melt yield stress Pa, L is the length of the straight section of the die lip cm, ΔP is the die head pressure drop MPa, and R is the equivalent radius of the flow channel cm;

[0034] The non-Newtonian index n of the PE / PP layer is 0.35-0.40, and the non-Newtonian index n of the EVA layer is 0.40-0.50.

[0035] By optimizing the VA content of the EVA anti-slip conforming layer (18%-30%) and the ratio of the PE / PP wear-resistant layer (70%-80% PE, 20%-30% PP), the anti-slip mat achieves a static coefficient of friction of 0.75-0.85 in dry conditions and maintains a coefficient of friction of 0.60-0.70 in wet conditions. This performance is primarily due to the hydrogen bonding between the polar groups of the EVA layer and the contact surface, as well as the surface microstructure formed by controlling the extrusion speed through the mechanical equation of motion, which increases the actual contact area by 30%-50%.

[0036] By controlling the line speed ratio of the two layers to 0.9-1.0:1.0-1.2 and combining it with specific processing aids, the air retention of the anti-slip mat is reduced to ≤4.5%, improving its conformability by over 70%. Furthermore, the interlayer peel strength is ≥2.0N / cm, ensuring long-term non-separation. This is primarily due to the formation of a melt interface diffusion layer (10-20μm) and a crystalline interlocking structure.

[0037] Specifically, one or more embodiments of the present invention provide a method for preparing a PEVA anti-slip mat, which is prepared by a layered co-extrusion process, and the specific steps are as follows:

[0038] Raw material preparation

[0039] PE / PP wear-resistant layer material: PE (such as LLDPE 7042) and PP (such as T30S) are mixed in a mass ratio of 7:3-8:2, 0.5%-2% of a lubricant (such as calcium stearate) and 0.2%-1% of an antioxidant (such as hindered phenol antioxidant 1010) are added, and the mixture is mixed in a high-speed mixer at 80-120°C for 10-15 minutes to uniformly disperse the materials.

[0040] Materials for the EVA anti-slip conformable layer: Select EVA resin with a VA content of 18%-30% (such as EVA 18J3), add 1%-3% processing aid (such as PE wax), and mix in a low-speed mixer at room temperature for 5-10 minutes to improve processing fluidity.

[0041] Two-layer co-extrusion

[0042] Two single-screw extruders are used to plasticize and extrude the PE / PP wear-resistant layer material and the EVA anti-slip conformable layer material respectively:

[0043] PE / PP layer extruder: screw diameter 65mm, aspect ratio 30:1, extrusion temperature set to 180-200℃ in the feeding section, 200-220℃ in the compression section, and 220-230℃ in the metering section. The shearing effect of the screw is used to fully blend and melt PE and PP.

[0044] EVA layer extruder: screw diameter 50mm, aspect ratio 28:1, extrusion temperature set to 150-160℃ in the feeding section, 160-170℃ in the compression section, and 170-180℃ in the metering section to avoid decomposition of vinyl acetate groups in EVA due to excessive temperature.

[0045] The two layers are compounded through a T-type co-extrusion die. The die temperature is controlled at 200-210°C to ensure consistent melt fluidity. The extrusion speed ratio of the two layers is controlled to be PE / PP layer:EVA layer = 0.9-1.0:1.0-1.2. The specific extrusion speed is determined by the following mechanical motion equation: Determine, where ν is the extrusion line speed m / min, n is the non-Newtonian index, Q is the melt volume flow rate cm / s; A is the die lip cross-sectional area cm 2 ;η is the melt viscosity Pa·s, τ y is the melt yield stress Pa, L is the length of the straight section of the die lip cm, ΔP is the die head pressure drop MPa, and R is the equivalent flow channel radius cm.

[0046] Cooling, shaping and post-processing

[0047] A three-stage cooling system is used: the first stage is mist water cooling at 50-100mm below the die head, with a water temperature of 20-25℃, which quickly solidifies the surface melt; the second stage is air cooling at a distance of 200-300mm from the die head with a wind volume of 500-800m 3 / h, uniformly cooling the middle layer; the third section is the contact cooling roller in front of the traction roller with a surface temperature of 15-20℃, ensuring the two-layer structure is fixed.

[0048] The cooled anti-slip mat passes through a traction machine, the traction speed matches the extrusion speed, and the error is ≤5%. It is then cut into the target size (such as 1000mm×500mm) by a cutter to obtain a finished product.

[0049] Specifically, the PEVA anti-slip mat provided in Example 1 of the present invention is:

[0050] (1) The raw material formula is as follows:

[0051] The EVA anti-slip conformable layer comprises 97% EVA (VA content 18%, brand 18J3) and 3% PE wax.

[0052] PE / PP wear-resistant layer, wherein the content of PE (LLDPE 7042) is 78%, the content of PP (T30S) is 20%, the content of calcium stearate is 1.5%, and the content of antioxidant 1010 is 0.5%.

[0053] The content of the EVA anti-slip conformable layer accounts for 30% of the total mass, and the content of the PE / PP wear-resistant layer accounts for 70% of the total mass.

[0054] (2) The preparation method of PEVA anti-slip mat is as follows:

[0055] Step 1: Raw material preparation

[0056] PE, PP, calcium stearate and antioxidant were added to a high-speed mixer and mixed at 120°C for 12 minutes to fully and evenly disperse the materials to prepare the PE / PP wear-resistant layer material; EVA and PE wax were mixed in a low-speed mixer at room temperature for 8 minutes to improve the processing fluidity of the EVA resin to prepare the EVA anti-slip and conformable layer material.

[0057] Step 2: Two-layer co-extrusion molding

[0058] Two single-screw extruders are used to plasticize and extrude the PE / PP wear-resistant layer material and the EVA anti-slip conforming layer material respectively: PE / PP layer extruder: the screw diameter is 65mm, the aspect ratio is 30:1, the temperature is set to 190℃ in the feeding section, 210℃ in the compression section, and 220℃ in the metering section. Through the rotation of the screw and temperature control, PE and PP are fully melted and blended.

[0059] EVA layer extruder: The screw diameter is 50mm, the aspect ratio is 28:1, and the temperature is set at 160℃ in the feeding section, 170℃ in the compression section, and 180℃ in the metering section to ensure that the EVA resin is plasticized at the appropriate temperature to avoid decomposition of the VA group.

[0060] The two layers of melt are compounded through a T-layer co-extrusion die, and the die temperature is controlled at 205°C to ensure that the two layers of melt have good fluidity and compatibility.

[0061] The extrusion speed of each layer is calculated by the mechanical motion equation:

[0062] For the PE / PP layer, the non-Newtonian index n = 0.38 and the melt volume flow rate Q = 120 cm 3 / s, die lip cross-sectional area A = 80 cm 2 , melt viscosity η=70Pa·s, melt yield stress τ y =450Pa, the straight section length of the die lip L = 8cm, the die head pressure drop ΔP = 7MPa, the equivalent flow channel radius R = 0.3cm, substituting into the equation we can get: PE / PP ≈0.65m / min;

[0063] For the EVA layer, the non-Newtonian index n = 0.45, the melt volume flow rate Q = 90 cm / s, and the die lip cross-sectional area A = 60 cm 2 , melt viscosity η=50Pa·s, melt yield stress τ y=300Pa, the length of the straight section of the die lip L = 8cm, the die head pressure drop ΔP = 6MPa, the equivalent radius of the flow channel R = 0.25cm, substituting into the equation we can get: EVA ≈0.72m / min.

[0064] The linear speed ratio of the PE / PP layer and the EVA layer is controlled to be 0.65:0.72≈0.9:1.08.

[0065] Step 3: Cooling, shaping and post-processing

[0066] A three-stage cooling system is used to cool and shape the anti-slip mat blank:

[0067] The first section is mist water cooling 100mm below the die head. The water temperature is controlled at 22℃, which quickly reduces the melt temperature and initially solidifies the surface layer.

[0068] The second section is air cooling 300mm away from the die head, and the air volume is set to 600m 3 / h, evenly cool the middle layer to prevent local overheating.

[0069] The third section is a contact cooling roller before the traction roller, the surface temperature of which is maintained at 18°C ​​to ensure that the two-layer structure is fully formed and avoids deformation.

[0070] The cooled anti-slip mat is pulled by a traction machine, and the pulling speed is controlled at 0.68m / min, which matches the extrusion speed with an error of no more than 5%.

[0071] Finally, the anti-slip mat is cut into finished products of 1000mm×600mm with a cutter, with a total thickness of 1.8mm, of which the thickness of the EVA anti-slip conformable layer is 0.7mm and the thickness of the PE / PP wear-resistant layer is 1.1mm.

[0072] Step 4: Performance test data

[0073] (1) Anti-slip performance test

[0074] Test method: In accordance with GB / T 3903.5-2013 "Footwear Test Methods - Anti-slip Performance", use a friction coefficient tester to test on dry and wet tile floors.

[0075] Test results: Dry tile surface: The static friction coefficient of the anti-slip mat of the present invention is 0.82, and the static friction coefficient of the commercially available single-layer PE anti-slip mat is 0.55. The static friction coefficient of the present invention is improved by about 49% compared with the commercially available product.

[0076] Wet tile surface: The static friction coefficient of the anti-slip mat of the present invention is 0.68, while the static friction coefficient of the commercially available single-layer PE anti-slip mat is 0.35. The static friction coefficient of the present invention is improved by about 94% compared with the commercially available product.

[0077] (2) Fit test

[0078] Test method: Place the anti-slip mat on a tile with a surface roughness of Ra = 1.5μm, and use the vacuum adsorption method to measure the amount of air remaining between the anti-slip mat and the tile surface.

[0079] Test results: The air residual content of the anti-slip mat of the present invention is 4.2%, while the air residual content of the commercially available single-layer PE anti-slip mat is 15.6%. The air residual content of the present invention is reduced by about 73% compared with the commercially available product, indicating that the fit is greatly improved.

[0080] (3) Interlayer bonding strength test

[0081] Test method: Use a tensile testing machine to test the interlayer peel strength according to GB / T 2791-1995 "Adhesive T-peel strength test method flexible material to flexible material" standard, and the test speed is 100mm / min.

[0082] Test results: The interlayer peeling strength of the anti-slip mat of the present invention is 2.3 N / cm, which meets the requirements for long-term use.

[0083] (4) Mechanical properties test

[0084] Tensile strength test: According to GB / T 1040.2-2006, "Plastics - Determination of Tensile Properties - Part 2: Test Conditions for Molded and Extruded Plastics," the anti-slip mat was formed into a standard dumbbell-shaped specimen and stretched at a speed of 50 mm / min. The test result showed a tensile strength of 9.5 MPa, approximately 27% higher than that of the pure PE layer.

[0085] Elongation at break test: carried out simultaneously with the tensile strength test, the test result showed an elongation at break of 280%, indicating good toughness.

[0086] 10% deformation compressive strength test: According to GB / T 1041-2008 "Determination of compression properties of plastics", the test result is 10% deformation compressive strength of 13.2MPa, which can withstand daily heavy pressure.

[0087] Specifically, the PEVA anti-slip mat provided in Example 2 of the present invention is prepared by adjusting the VA content of the EVA anti-slip conformable layer based on Example 1, with the VA content being 25% and 30% respectively, while other formulas and process parameters remain unchanged.

[0088] Performance test results are shown in Table 1. When the VA content of the EVA is between 18% and 30%, the anti-slip mat exhibits excellent anti-slip performance and interlayer adhesion. At 18% VA, the static coefficient of friction reaches high values ​​in both dry and wet environments, and interlayer adhesion is also ideal. This is because increasing the VA content increases the polarity and flexibility of the EVA, enhancing the intermolecular forces and adhesion to the contact surface. However, excessive VA content can reduce the strength of the EVA and affect interlayer adhesion. Therefore, a VA content of 18% to 30% is preferred, with 18% being the optimal value.

[0089] Table 1 Performance test results of anti-slip mats with different VA contents

[0090]

[0091]

[0092] Specifically, the PEVA anti-slip mat provided in Example 3 of the present invention is adjusted based on Example 1, with the PP content in the PE / PP wear-resistant layer being 25% and 30%, respectively. The performance test results are shown in Table 2. Table 2 Performance test results of anti-slip mats with different PP contents

[0093]

[0094] As the PP content increases, the tensile strength, 10% deformation compressive strength, and wear resistance of the PE / PP wear-resistant layer gradually improve, but the elongation at break decreases somewhat. When the PP content is 20%-25%, the wear-resistant layer combines high strength, wear resistance, and a certain degree of toughness, meeting the needs of daily use. When the PP content exceeds 25%, although the strength and wear resistance are further improved, the elongation at break decreases significantly, the material's toughness deteriorates, and it is prone to cracking. Therefore, a PP content of 20%-30% is preferred, with 20% being the optimal.

[0095] Specifically, a PEVA anti-slip mat provided in Example 4 of the present invention is prepared by adjusting the extrusion temperatures of the PE / PP wear-resistant layer and the EVA anti-slip conforming layer on the basis of Example 1, while keeping other process parameters unchanged, as follows:

[0096] Low temperature combination:

[0097] PE / PP layer extrusion temperature: feeding section 180℃, compression section 200℃, metering section 210℃;

[0098] EVA layer extrusion temperature: feeding section 150℃, compression section 160℃, metering section 170℃.

[0099] High temperature combination:

[0100] PE / PP layer extrusion temperature: feeding section 200℃, compression section 220℃, metering section 230℃;

[0101] EVA layer extrusion temperature: feeding section 170℃, compression section 180℃, metering section 190℃.

[0102] The performance test results are shown in Table 3.

[0103] Table 3 Performance test results of anti-slip mats at different extrusion temperatures

[0104]

[0105] Extrusion temperature has an important influence on the interlayer bonding strength and the stability of the EVA layer. Under low-temperature combinations, the melt fluidity is poor, and the interface diffusion of the two melt layers is insufficient, resulting in low interlayer peeling strength. Under medium-temperature combinations, the melt fluidity is moderate, the interface bonding is good, and the interlayer peeling strength reaches the best. Although the high-temperature combination has better melt fluidity, the EVA layer undergoes slight thermal decomposition and the VA group is lost, which affects the polarity and flexibility of the EVA and leads to a decrease in interlayer bonding strength. Therefore, the preferred extrusion temperature for the PE / PP layer is 180-230°C, and the extrusion temperature for the EVA layer is 150-180°C, with the best being the medium-temperature combination.

[0106] Specifically, a PEVA anti-slip mat provided in Example 5 of the present invention is prepared as follows, based on Example 1, with the linear speed ratio of the PE / PP layer to the EVA layer adjusted, while other formulations and process parameters remain unchanged:

[0107] Line speed ratio 0.8:1.1: PE / PP layer line speed 0.58m / min, EVA layer line speed 0.80m / min;

[0108] Line speed ratio 1.0:1.0: PE / PP layer line speed 0.72m / min, EVA layer line speed 0.72m / min;

[0109] Line speed ratio 1.1:0.9: PE / PP layer line speed 0.80m / min, EVA layer line speed 0.65m / min.

[0110] The performance test results are shown in Table 4.

[0111] Table 4 Performance test results of anti-slip pads at different linear speed ratios

[0112]

[0113] The linear velocity ratio directly affects the composite uniformity and interfacial bonding strength of the two melt layers. When the linear velocity ratio is 0.9-1.0:1.0-1.2, the residence time of the two melt layers in the mold is highly matched, and interfacial diffusion is sufficient, which not only ensures the elastic deformation capacity of the EVA layer but also enables the PE / PP layer to provide stable support. At this time, the anti-slip properties and interlayer bonding strength are optimally balanced. A linear velocity ratio that is too small (such as 0.8:1.1) will cause the EVA layer to extrude too quickly, resulting in wrinkles. A linear velocity ratio that is too large (such as 1.1:0.9) will cause the PE / PP layer to dominate the flow, causing the EVA layer to be stretched and thinned, and the thickness uniformity of the two layers will be affected.

[0114] Specifically, a PEVA anti-slip mat provided in Example 6 of the present invention, based on Example 1, controls the extrusion line speeds of the PE / PP layer and the EVA layer by changing the non-Newtonian exponent n and the die pressure drop ΔP in the mechanical motion equation. The specific parameters are set as follows:

[0115] Control group A: The extrusion speed was set only by experience, without using the mechanical motion equations.

[0116] PE / PP layer line speed: 0.7m / min (empirical value);

[0117] EVA layer line speed: 0.7m / min (experience value);

[0118] Experimental Group B: Using the equation of motion to calculate and adjust the non-Newtonian index n

[0119] PE / PP layer: n = 0.35 (lower than the conventional value of 0.38);

[0120] EVA layer: n = 0.50 (higher than the conventional value of 0.45);

[0121] The calculated linear speed of the PE / PP layer is 0.62 m / min, and the linear speed of the EVA layer is 0.75 m / min.

[0122] Experimental Group C: Using the equation of motion to calculate, adjust the die pressure drop ΔP

[0123] PE / PP layer: ΔP = 6MPa (lower than the normal value of 7MPa);

[0124] EVA layer: ΔP = 7 MPa (6 MPa higher than the normal value);

[0125] The calculated linear speed of the PE / PP layer is 0.58 m / min, and the linear speed of the EVA layer is 0.80 m / min.

[0126] Experimental Group D: Calculation of Standard Mechanical Equations of Motion (Parameters of Example 1)

[0127] PE / PP layer: n = 0.38, ΔP = 7 MPa;

[0128] EVA layer: n = 0.45, ΔP = 6 MPa;

[0129] The calculated linear speed of the PE / PP layer is 0.65 m / min, and the linear speed of the EVA layer is 0.72 m / min.

[0130] The performance test results are shown in Table 5.

[0131]

[0132] Experimental Group D, by precisely controlling the non-Newtonian exponent n and the die pressure drop ΔP, matched the EVA layer's extrusion speed to its elastic deformation capacity, achieving a wet coefficient of friction of 0.68, a 13.3% improvement over Control Group A. This is because the equation calculation ensured that the EVA layer retained more VA polar groups during the extrusion process (SEM observations showed a VA group loss rate of less than 5%), enhancing the water bridge interaction with the wet surface.

[0133] In experimental group B, the n value of the PE / PP layer was reduced, which increased the melt fluidity. The linear speed ratio of the PE / PP layer to the EVA layer was close to 0.83:1. The EVA layer produced moderate stretching during compounding, and the surface micro-convex structure increased (AFM detection roughness Ra increased from 1.2μm to 1.5μm), thereby improving the anti-slip properties.

[0134] The residual air content of experimental group D is only 4.2%, which is 38.2% lower than that of control group A. Because the equation calculates that the residence time difference between the two layers of melt in the mold is less than 10%, the EVA layer can maintain more than 90% of the initial elastic modulus (15MPa), effectively filling the table groove.

[0135] Experimental group C increased the EVA layer die pressure drop ΔP to increase the melt shear rate to 1200s -1 The orientation degree of EVA molecular chain increases, and after cooling, a micro-wrinkle structure is formed along the extrusion direction (SEM observation wrinkle density 10-15 / mm), which further enhances the fit.

[0136] The interlayer peel strength of experimental group D reached 2.3N / cm. Due to the equation calculation, the temperature difference between the two layers of melt was controlled at 40-50℃ (220℃ for PE / PP layer and 180℃ for EVA layer), the thickness of the interfacial diffusion layer reached 15-20μm, and the crystalline segments of PE and the amorphous segments of EVA formed an interlocking structure (DSC detection showed that the interfacial crystallinity decreased by 8%).

[0137] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the scope of the present invention, the above embodiments or technical features in different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0138] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A PEVA anti-slip mat, characterized in that: The anti-slip mat adopts a two-layer co-extrusion structure, which is as follows from bottom to top: The EVA anti-slip conformable layer is made of EVA, wherein the EVA content accounts for 30%-40% of the mass; The PE / PP wear-resistant layer is made of a PE / PP blend, wherein the PE content is 70%-80%, the PP content is 20%-30%, and the PE / PP content accounts for 60%-70% of the mass.

2. The PEVA anti-slip mat according to claim 1, characterized in that: The VA content of the EVA in the EVA anti-slip conformable layer is 18%-30%.

3. The PEVA anti-slip mat according to claim 1, characterized in that: 0.5%-2% of lubricant and 0.2%-1% of antioxidant are also added to the PE / PP wear-resistant layer.

4. The PEVA anti-slip mat according to claim 3, characterized in that: The lubricant is one or more of calcium stearate, zinc stearate or polyethylene wax, and the antioxidant is one or more of hindered phenol or phosphite antioxidants.

5. The PEVA anti-slip mat according to claim 1, characterized in that: The interlayer peeling strength between the EVA anti-slip conformable layer and the PE / PP wear-resistant layer is ≥2.0N / cm.

6. A method for preparing the PEVA anti-slip mat according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: Raw material preparation: Mix PE and PP in a mass ratio of 70%-80%:20%-30%, add lubricant and antioxidant, and mix evenly to obtain the PE / PP wear-resistant layer material; mix EVA resin with processing aids to obtain the EVA anti-slip conformable layer material; Two-layer co-extrusion molding: Two single-screw extruders are used to plasticize and extrude the PE / PP wear-resistant layer material and the EVA anti-slip conformable layer material respectively, and then compounded through a layer co-extrusion die. The linear speed ratio of the PE / PP layer to the EVA layer is controlled at 0.9-1.0:1.0-1.2; Cooling, shaping and post-processing: The anti-slip mat blank is cooled through a three-stage cooling system, and the finished product is obtained through pulling and cutting.

7. The preparation method according to claim 6, characterized in that The extrusion temperature of the PE / PP wear-resistant layer is 180-230°C, the extrusion temperature of the EVA anti-slip conformable layer is 150-180°C, and the die head temperature is 200-210°C.

8. The preparation method according to claim 6, characterized in that During the two-layer co-extrusion process, the extrusion speed of each layer is determined by the mechanical motion equation Determine, where ν is the extrusion line speed m / min, n is the non-Newtonian index, Q is the melt volume flow rate cm / s; A is the die lip cross-sectional area cm 2 ;η is the melt viscosity Pa·s, τ y is the melt yield stress Pa, L is the length of the straight section of the die lip cm, ΔP is the die head pressure drop MPa, and R is the equivalent radius of the flow channel cm; The non-Newtonian index n of the PE / PP layer is 0.35-0.40, and the non-Newtonian index n of the EVA layer is 0.40-0.

50.

9. The preparation method according to claim 6, characterized in that The three-stage cooling system includes mist water cooling, air cooling and contact cooling roller cooling in sequence. The mist water cooling temperature is 20-25°C, and the surface temperature of the contact cooling roller is 15-20°C.

10. The preparation method according to claim 6, characterized in that The amount of the processing aid added to the EVA anti-slip conformable layer material is 1%-3%, and the processing aid is PE wax.

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