Polyolefin-based LVT floor and preparation method thereof

Abstract

The invention relates to an LVT floor, in particular to a polyolefin-based LVT floor and a preparation method thereof. Belongs to the technical field of indoor floors. The polyolefin-based LVT floor sequentially comprises a balance layer, a polyolefin base material layer, a color film layer and a wear-resistant layer from bottom to top, the wear-resistant layer comprises a prefabricated wear-resistant sheet made of a PET (Polyethylene Terephthalate) material and a UV (Ultraviolet) wear-resistant layer arranged on the basis of the prefabricated wear-resistant sheet; the color film layer comprises a PET background film layer and a pattern layer arranged based on the PET background film layer. According to the polyolefin-based LVT floor provided by the invention, through material innovation and structure optimization, the comprehensive problems of the traditional LVT floor in the aspects of wear resistance, pattern adhesive force and interlayer bonding strength are systematically solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of LVT floor, especially a kind of polyolefin-based LVT floor and its preparation method.It belongs to indoor floor technical field. BACKGROUND

[0002] LVT (Luxury Vinyl Tile) is a kind of semi-hard sheet plastic elastic floor.Vinyl is the most economical cost in vinyl resin, so the LVT on the market is almost polyvinyl floor at present.For example, the patent for invention with the authorization announcement No.CN 112922266 B discloses an indoor LVT floor.The floor includes substrate layer, color film layer and wear-resistant layer, and the substrate layer includes elastic layer, reinforcing layer and bottom layer from top to bottom;compared with the bottom layer, the elastic layer filler is low, the plasticizer is high, the reinforcing layer filler is high, and the plasticizer is low, so that the reinforcing layer is relatively hard, the elastic layer is relatively soft, and the bottom layer is moderate, and the soft elastic characteristics of the elastic layer and the bottom layer are used to reduce the warping degree of the floor.Because polyvinyl chloride molecule contains chlorine atom, toxic gas is released during combustion, and plasticizer such as dioctyl phthalate is easy to migrate and separate out, which has health risk.

[0003] In order to overcome the above problems, the industry proposes a technical scheme of replacing polyvinyl with polyolefin as LVT floor substrate.But due to the difference between polyolefin and polyvinyl, when the substrate is changed to polyolefin, the color film layer and wear-resistant layer originally suitable for polyvinyl substrate are no longer suitable.If polyvinyl color film is replaced with polypropylene color film, due to the low polarity of polypropylene film surface, the ink has weak binding force with it, which will also cause the pattern of color film layer to fall off or fade, affecting the decoration effect and service life. SUMMARY

[0004] The present application solves the above problems, and provides a kind of polyolefin-based LVT floor.The polyolefin-based LVT floor of the present application uses PET material wear-resistant sheet and background film layer to solve the problem of poor ink adhesion.

[0005] The technical scheme for solving the above problems is as follows: A kind of polyolefin-based LVT floor, from bottom to top, includes balancing layer, polyolefin substrate layer, color film layer and wear-resistant layer;The wear-resistant layer includes preformed wear-resistant sheet of PET material and UV wear-resistant layer based on the preformed wear-resistant sheet;The color film layer includes PET background film layer and pattern layer based on the PET background film layer.

[0006] In the above technical solution of the present application, the UV wear-resistant layer is arranged on the prefabricated wear-resistant sheet, and the wear-resistant layer is prepared in the form of prefabricated sheet+UV layer. It is found in the test that: if only the UV layer is used, the wear-resistant revolution cannot meet the requirements; if only the UV layer is used and the thickness is increased, although the wear-resistant revolution can meet the requirements, the wear-resistant layer becomes hard and brittle, which does not meet the use habit; only the prefabricated sheet, the surface hardness is insufficient, and it is easy to scratch in the wear-resistant test. Therefore, in the above technical solution, the prefabricated sheet provides toughness, and the UV layer provides wear resistance, and the two cooperate to satisfy the synergistic effect of toughness and wear resistance.

[0007] In the above technical solution of the present application, PET is a polymer obtained by polycondensation of terephthalic acid and ethylene glycol. It is a polar polymer, and various patterns such as wood grain or stone grain can be easily made thereon, and the pattern layer has good bonding force.

[0008] As a preferred embodiment of the above technical solution, the pattern layer is prepared by printing or thermal transfer on the PET background film layer.

[0009] As a preferred embodiment of the above technical solution, the polyolefin base material layer comprises a basic base material layer and a modified base material layer located above the basic base material layer; The basic base material layer is composed of the following components by mass fraction: Polyolefin resin 80~100, polyolefin elastomer 15~20, filler 10~30, stabilizer 2~5, processing aid 2~5; The modified base material layer is composed of the following components by mass fraction: Polyolefin resin 40~60, polyolefin grafting modified resin 20~40, polyolefin elastomer 10~20, filler 10~20, modified filler 2~5, stabilizer 2~5, processing aid 2~5; the modified filler is nano silicon dioxide treated with silane coupling agent. The polyolefin grafting modified resin can be maleic anhydride grafting modified polyethylene / polypropylene.

[0010] Elastomer is a kind of high polymer material which deforms significantly under weak stress and can quickly recover to the original state and size after stress relaxation. In the above technical solution of the present application, the polyolefin elastomer is an elastomer obtained by random copolymerization of ethylene and other α-olefins (such as 1-butene, 1-octene, etc.); the molecular chain of the polyolefin elastomer is usually composed of hard segments (such as polyethylene crystalline segments) and soft segments (such as ethylene-butene copolymer segments, ethylene-octene copolymer segments); the content of other α-olefins is more than 15% (generally more than 20%); a large amount of other α-olefins weaken the crystalline region of the carbon-carbon main chain, forming an amorphous region exhibiting rubber elasticity. In the above technical solution of the present application, by blending the polyolefin resin and the polyolefin elastomer, the flexibility of the base material is significantly improved, and the LVT floor has better soft touch.

[0011] Since olefin resins or olefin elastomers are almost non-polar, it is difficult for PET background films to form a strong bond with them. Therefore, in the above-mentioned technical solution of the present invention, a polyolefin graft-modified resin, such as PE-g-MAH or PP-g-MAH, is added to the formulation of the modified substrate layer. The graft-modified resin introduces carboxyl side chains on the carbon-carbon backbone, and after blending, it can significantly increase the surface carboxyl content of the modified substrate layer.

[0012] In the above technical solution of the present invention, in order to further improve the bonding between the PET background film and the modified substrate layer, the PET background film is also subjected to corona treatment.

[0013] While both PET and CH bonds undergo corona treatment, the results are significantly better on PET than on the substrate. This is because the substrate, being a polyolefin, has lower polarity and surface energy. Corona treatment primarily targets CC and CH bonds, requiring higher energy input. Furthermore, polyolefin corona treatment exhibits a self-healing effect, meaning it has poor durability and needs to be completed quickly. Otherwise, the surface polar groups may migrate or redistribute over time, significantly reducing surface energy; and the product is prone to delamination or cracking after long-term use. In contrast, PET corona treatment primarily targets R-COO-R bonds, generating a large number of hydroxyl and carboxyl groups. Simultaneously, the dispersed addition of nano-silica in the modified substrate layer increases the surface hydroxyl content. Therefore, compatibility with the modified substrate layer can be improved through hydrogen bonding or dipole interactions, and covalent bonding can be achieved through the reaction of hydroxyl and carboxyl groups, significantly enhancing the bonding strength between the two. That is, the present invention modifies the surface of the substrate layer to introduce carboxyl and hydroxyl groups on its surface; and secondly, it generates a large number of carboxyl and hydroxyl groups on the surface of the PET background film by corona treatment; thereby enabling the two to improve compatibility and binding through hydrogen bonding or dipole interaction between hydroxyl and / or carboxyl groups, and to improve covalent bonding through esterification reaction between hydroxyl and carboxyl groups.

[0014] As a preferred embodiment of the above technical solution, the color filter layer includes a UV protective layer disposed on the surface of the pattern layer.

[0015] As a further preferred embodiment of the above technical solution, a first adhesive layer is also provided between the UV protective layer and the prefabricated wear-resistant sheet.

[0016] In the above-described technical solution of this invention, the UV protective layer is essentially a cured layer formed by the polymerization of acrylate monomers or oligomers initiated by ultraviolet (UV-A) light. Compared to other layers, it typically has higher rigidity, thus providing protection. Furthermore, the first adhesive layer based on this layer exhibits good adhesion, and the first adhesive layer demonstrates good coatability, facilitating process implementation. More importantly, the first adhesive layer often undergoes volume shrinkage during curing, which can exert mechanical stress on the pattern layer, leading to pattern blurring; the UV protective layer effectively counteracts this effect. While the UV protective layer itself also shrinks during curing, the degree of shrinkage differs significantly, and the amount of UV coating is very small, making the negative impact of shrinkage on the pattern negligible.

[0017] As a preferred embodiment of the above technical solution, a second adhesive layer is further provided between the modified substrate layer and the PET background film layer.

[0018] In the above technical solution of the present invention, the bonding between the modified substrate layer and the PET film layer is improved by setting an adhesive layer between the two.

[0019] As a further preferred embodiment of the above technical solution, the adhesion between the two is further improved by first spraying a surface agent onto the modified substrate layer and then setting a second adhesive layer. The surface agent is selected from at least one of silane coupling agents, hydroxy acrylate monomers, carboxyacrylate monomers, and acrylate oligomers.

[0020] As a further preferred embodiment of the above technical solution, the surface of the modified substrate is first sanded with a belt sander, then a surface agent is sprayed, and then a second adhesive layer is applied.

[0021] As a preferred embodiment of the above technical solution, the pattern layer is a wood grain pattern layer.

[0022] Another object of the present invention is to provide a method for preparing the above-mentioned polyolefin-based LVT flooring.

[0023] The technical solution is as follows: A method for preparing polyolefin-based LVT flooring includes the following steps: S1. A polyolefin substrate layer with a balancing layer on the back and a PET background film layer on the decorative surface is provided; S2. A pattern layer is formed on the PET background film by printing or heat transfer. S3. Spray / roll coat UV resin onto the patterned layer, and then cure it with UV-A band light to produce a UV protective layer with a thickness of 10~50μm. S4. Spray / roll-coat the first adhesive onto the UV protective layer; S5. Lay the PET pre-made abrasion-resistant sheet onto the color film layer; S6. Spray / roll-coat UV resin onto the PET prefabricated wear-resistant sheet, and then cure it with UV-A band light to produce a UV wear-resistant layer with a thickness of more than 100μm.

[0024] As a preferred embodiment of the above technical solution, step S1 is as follows: S11. The first resin composition for forming the base substrate layer is fed into the first main extruder; S12. The second resin composition for forming the modified substrate layer is fed into the second main extruder; S13. The first resin composition and the second resin composition are co-extruded from the first co-extrusion die through the first main extruder and the second main extruder respectively to obtain the polyolefin substrate layer; S14. Pass the polyolefin substrate layer into the main runner of the second co-extrusion die; S15. Using a first auxiliary extruder, the third resin composition for forming the balance layer is melt-extruded into the first side channel of the second co-extrusion die; S16. Using a second auxiliary extruder, the polyurethane hot melt adhesive used to form the second adhesive layer is melted and extruded into the second side channel of the second co-extrusion die; S17. The third resin composition and polyurethane hot melt adhesive are extruded from the second co-extrusion die through the first auxiliary extruder and the second auxiliary extruder respectively to obtain a polyolefin substrate layer with a balance layer on the back and a second adhesive layer on the decorative surface. S18. The polyolefin substrate layer obtained in step S17 is hot-pressed together with the PET background film layer through the second adhesive layer to obtain a polyolefin substrate layer with a balancing layer on the back and a PET background film layer on the decorative surface.

[0025] As another preferred embodiment of the above technical solution, step S1 is as follows: S11. The first resin composition for forming the base substrate layer is fed into the first main extruder; S12. The second resin composition for forming the modified substrate layer is fed into the second main extruder; S13. The first resin composition and the second resin composition are co-extruded from the first co-extrusion die through the first main extruder and the second main extruder respectively to obtain the polyolefin substrate layer; S14. Pass the polyolefin substrate layer into the main runner of the second co-extrusion die; S15. Using a first auxiliary extruder, the third resin composition for forming the balance layer is melt-extruded into the first side channel of the second co-extrusion die; S16. Using a second auxiliary extruder, the polyurethane hot melt adhesive used to form the second adhesive layer is melted and extruded into the second side channel of the second co-extrusion die; S17. Using a third auxiliary extruder, melt the PET resin used to form the PET background film layer and extrude it into the third side channel of the second co-extrusion die; S18. The third resin composition, polyurethane hot melt adhesive and PET resin are extruded from the second co-extrusion die through the first auxiliary extruder, the second auxiliary extruder and the third auxiliary extruder respectively, to obtain the polyolefin substrate layer with a balancing layer on the back and a PET background film layer on the decorative surface.

[0026] In summary, the present invention has the following beneficial effects: 1. This invention provides a polyolefin-based LVT flooring that, through material innovation and structural optimization, systematically solves the comprehensive problems of traditional LVT flooring in terms of wear resistance, pattern adhesion, and interlayer bonding strength. 2. A balance between flexibility and high hardness is achieved through the composite design of pre-formed sheets (PET material) and a UV abrasion-resistant layer. The high elongation at break of the pre-formed sheet effectively absorbs impact energy, preventing brittle fracture; the UV abrasion-resistant layer provides high hardness, significantly enhancing surface scratch resistance; the two work together to achieve an abrasion resistance rating of 5000 revolutions (EN13329); the combination of pre-formed sheet and UV layer reduces the number of abrasion layer coatings, increasing production efficiency by more than 30%; at the same time, the impact resistance is optimized, allowing it to withstand heavy impacts without easily cracking, meeting the needs of high-traffic commercial spaces; 3. Using PET background film instead of traditional PVC material, its polar molecular structure (containing ester bonds R-COO-R) supports direct printing or heat transfer of patterns, achieving firm adhesion without additional treatment; PET's high glass transition temperature (Tg>70℃) ensures that the pattern will not deform or fade in high-temperature underfloor heating environments, and combined with a UV protective layer to further block ultraviolet rays, it solves the problems of easy peeling and poor heat resistance of traditional PVC colored film, significantly improving the long-term stability of the floor; 4. The polyolefin substrate layer is divided into a basic substrate layer and a modified substrate layer. The basic substrate layer is modified with polyolefin elastomers (such as ethylene-octene copolymer) to improve flexibility. The modified substrate layer is dually modified with grafted modified resins (such as PP-g-MAH) and polyolefin elastomers (such as ethylene-octene copolymer). The elastomer rubber phase gives the substrate a soft touch and improves foot comfort. The grafted modified resin introduces carboxyl groups on the surface, which, combined with the surface hydroxyl groups of nano-silica, increases the surface carboxyl group content by 3 to 5 times. This significantly improves the bonding strength with the PET background film (preferably by generating hydroxyl and carboxyl groups in situ on the surface through corona treatment), and solves the problem of easy delamination between layers caused by the low polarity of traditional polyolefin substrates. 5. The use of polyurethane hot melt adhesive layer and UV protective layer to offset the stress of adhesive curing shrinkage achieves a comprehensive improvement in interlayer bonding strength; UV protective layer effectively avoids blurring of pattern layer caused by adhesive shrinkage, ensuring no delamination and clear pattern over long-term use. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of Example 1; Figure 2 yes Figure 1 A magnified view of a portion of the image; In the diagram, the component names represented by each label are as follows: 1-Abrasion-resistant layer, 2- First adhesive layer, 3-Color filter layer, 4-Second adhesive layer, 5-Polyolefin substrate layer, 6-Balance layer, 11-Pre-fabricated wear-resistant sheet, 12-UV wear-resistant layer, 31-PET background film layer, 32-Pattern layer, 33-UV protective layer, 51 - Basic substrate layer 52-Modified substrate layer. Detailed Implementation

[0028] The present invention will be further explained and described below with reference to the accompanying drawings.

[0029] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. Any changes made by those skilled in the art after reading the specification of the present invention, as long as they are within the scope of the claims, will be protected by patent law. Example 1

[0030] like Figures 1-2 As shown, a polyolefin-based LVT flooring comprises, from top to bottom, a wear-resistant layer 1, a first adhesive layer 2, a color film layer 3, a second adhesive layer 4, a polyolefin substrate layer 5, and a balancing layer 6.

[0031] The wear-resistant layer 1 comprises a pre-fabricated wear-resistant sheet 11 made of PET material and a UV wear-resistant layer 12 based on the pre-fabricated wear-resistant sheet. The thickness of the pre-fabricated wear-resistant sheet 11 is approximately 200 μm, and the thickness of the UV wear-resistant layer is approximately 120 μm. The first adhesive layer 2 is formed by curing a polyurethane acrylate emulsion and has a thickness of approximately 30 μm. The color filter layer 3 comprises a PET background film layer 31, a pattern layer 32 based on the PET background film layer, and a UV protective layer 33 covering the pattern layer 32. The thickness of the PET background film layer 31 is approximately 100 μm, the thickness of the pattern layer 32 is less than 20 μm, and the thickness of the UV protective layer 33 is approximately 30 μm. The second adhesive layer 4 is a polyurethane hot melt adhesive layer with a thickness of approximately 100 μm. The polyolefin substrate layer 5 comprises a base substrate layer 51 and a modified substrate layer 52. The thickness of the base substrate layer 51 is approximately 3.5 mm, and the thickness of the modified substrate layer 52 is approximately 1.5 mm. The balancing layer 6 has a thickness of approximately 0.2 mm.

[0032] The formulation of the base substrate layer 51 is as follows, calculated in parts by weight: Polypropylene resin 100, POE elastomer (1-octene content > 20%) 20, calcium carbonate 20, stabilizer 3, processing aid 2; The formulation of the modified substrate layer 52 is as follows, calculated in parts by weight: Polypropylene resin 65, PP-g-MAH resin 35, POE elastomer (1-octene content > 20%) 20, calcium carbonate 20, stabilizer 3, processing aid 2; The formula for balance layer 6 is as follows, calculated in parts by weight: Polypropylene resin 65, POE elastomer (1-octene content > 20%) 35, stabilizer 3, processing aid 2.

[0033] The preparation method of the above-mentioned polyolefin-based LVT flooring includes the following steps: S1. The process of creating a polyolefin substrate layer 5 with a balancing layer 6 on the back and a PET background film layer 31 on the decorative surface includes the following steps: S11. The first resin composition for forming the base substrate layer 51 is fed into the first main extruder; S12. The second resin composition for forming the modified substrate layer 52 is fed into the second main extruder; S13. The first resin composition and the second resin composition are co-extruded from the first co-extrusion die through the first main extruder and the second main extruder respectively to obtain the polyolefin substrate layer 5. S14. Pass the polyolefin substrate layer 5 into the main runner of the second co-extrusion die; S15. Using a first auxiliary extruder, the third resin composition used to form the balance layer 6 is melted and extruded into the first side channel of the second co-extrusion die; S16. Using a second auxiliary extruder, the polyurethane hot melt adhesive used to form the second adhesive layer 4 is melted and extruded into the second side channel of the second co-extrusion die; S17. Using a third auxiliary extruder, PET resin for forming the PET background film layer 31 is melted and extruded into the third side channel of the second co-extrusion die; S18. The third resin composition, polyurethane hot melt adhesive and PET resin are extruded from the second co-extrusion die through the first auxiliary extruder, the second auxiliary extruder and the third auxiliary extruder respectively, to obtain a polyolefin substrate layer 5 with a balance layer 6 on the back and a PET background film layer 31 on the decorative surface. S2. A pattern layer 32 is formed on the PET background film layer 31 by printing. S3. Spray UV resin onto the patterned layer 32, and then cure it with UV-A band light to produce a UV protective layer 33 with a thickness of about 30μm. S4. Roller-coating the first adhesive onto the UV protective layer 33; S5. The PET pre-fabricated abrasion-resistant sheet 11 is attached to the color film layer 3; S6. Spray UV resin onto the PET prefabricated wear-resistant sheet 11, and then cure it with UV-A band light to produce a UV wear-resistant layer 12 with a thickness of 120μm. Example 2

[0034] The difference from Example 1 is that step S1, which involves preparing a polyolefin substrate layer 5 with a balancing layer 6 on the back and a PET background film layer 31 on the decorative surface, specifically includes the following steps: S11. The first resin composition for forming the base substrate layer 51 is fed into the first main extruder; S12. The second resin composition for forming the modified substrate layer 52 is fed into the second main extruder; S13. The first resin composition and the second resin composition are co-extruded from the first co-extrusion die through the first main extruder and the second main extruder respectively to obtain the polyolefin substrate layer 5. S14. Pass the polyolefin substrate layer 5 into the main runner of the second co-extrusion die; S15. Using a first auxiliary extruder, the third resin composition used to form the balance layer 6 is melted and extruded into the first side channel of the second co-extrusion die; S16. Using a second auxiliary extruder, the polyurethane hot melt adhesive used to form the second adhesive layer 4 is melted and extruded into the second side channel of the second co-extrusion die; S17. The third resin composition and polyurethane hot melt adhesive are extruded from the second co-extrusion die through the first auxiliary extruder and the second auxiliary extruder respectively to obtain a polyolefin substrate layer 5 with a balance layer 6 on the back and a second adhesive layer 4 on the decorative surface. S18. The polyolefin substrate layer 5 prepared in step S17 is hot-pressed together with the pre-made PET background film layer 31 through the second adhesive layer 4 to obtain the polyolefin substrate layer 5 with a balancing layer 6 on the back and a PET background film layer 31 on the decorative surface; in this embodiment, the second adhesive is also a polyurethane hot melt adhesive; and the pre-made PET background film layer 31 has been treated with double-sided corona treatment. Example 3

[0035] The difference from Example 1 is that the polyolefin-based LVT floor does not contain a first adhesive layer. Example 4

[0036] The difference from Example 1 is that the polyolefin-based LVT floor does not contain a second adhesive layer. Example 5

[0037] The difference from Example 1 is that the polyolefin-based LVT floor does not contain a UV protection layer.

[0038] Comparative Example 1 A polyolefin-based LVT flooring comprises, from top to bottom, a wear-resistant layer 1, a first adhesive layer 2, a color film layer 3, a second adhesive layer 4, a polyolefin substrate layer 5, and a balancing layer 6.

[0039] The wear-resistant layer 1 and the first adhesive layer 2 are the same as in Example 1.

[0040] The color filter layer 3 includes a PP background film layer 31, a pattern layer 32 formed on the PP background film layer, and a UV protection layer 33 covering the pattern layer 32. The PP background film layer 31 has a thickness of approximately 100 μm, the pattern layer 32 has a thickness of less than 20 μm, and the UV protection layer 33 has a thickness of approximately 30 μm. The PP background film layer 31 undergoes double-sided corona treatment.

[0041] The second adhesive layer 4, the polyolefin substrate layer 5, and the balancing layer 6 are the same as in Example 1.

[0042] The relevant performance of Examples 1 to 5 and Comparative Example 1 were tested in accordance with ISO 24345, and the results are shown in Table 1.

[0043] Table 1. Impregnation and peeling properties of each specimen Test criteria Peel strength (N / 50mm) Example 1 ISO 24345 120 Example 2 ISO 24345 113 Example 3 ISO 24345 81 Example 4 ISO 24345 57 Example 5 ISO 24345 116 Comparative Example 1 ISO 24345 93 , As shown in Table 1, Example 1 is a "full-function configuration": it includes a PET background film, a pattern layer, a UV protective layer, a double adhesive layer, a UV abrasion-resistant layer, and a pre-fabricated abrasion-resistant sheet; its peel strength reaches 120N / 50mm, which is the best among all specimens. This indicates that when the PET background film and the polyolefin substrate layer are effectively bonded together by polyurethane hot melt adhesive (second adhesive layer), and the UV protective layer alleviates the shrinkage stress of the adhesive layer, and the overall structural design is reasonable, the interlayer bonding strength is the highest and the system is the most stable.

[0044] Example 4, without the second adhesive layer, shows a sharp drop in peel strength to 57 N / 50 mm, the lowest among all examples. This demonstrates that the second adhesive layer (i.e., the polyurethane hot melt adhesive layer between the PET background film and the polyolefin substrate) is crucial for ensuring the bond between the PET and polyolefin layers; without this layer, delamination or peeling easily occurs between the PET (high polarity) and the polyolefin (low polarity).

[0045] Example 3, which does not contain a first adhesive layer (i.e., no adhesive between the UV protective layer and the prefabricated abrasion-resistant sheet), has a peel strength of 81 N / 50 mm. Although it still maintains a medium-to-high bonding strength, it is significantly lower than that of Examples 1 (120), 2 (113), and 5 (116) which contain a first adhesive layer. This indicates that the first adhesive layer (typically a polyurethane acrylate) acts as an adhesive transition between the UV protective layer and the abrasion-resistant layer, contributing to the overall structural stability, especially preventing interface separation when the abrasion-resistant layer is under stress.

[0046] Example 5, without a UV protective layer but retaining the first and second adhesive layers, achieved a peel strength of 116 N / 50 mm, which is still relatively high. Although slightly lower than Example 1 (120), it is significantly higher than Example 4 (57) without the second adhesive layer or Example 3 (81) without the first adhesive layer. This indicates that although the UV protective layer itself does not directly participate in the bonding, its low curing shrinkage rate can offset the stress effect of the first adhesive layer on the pattern layer and film layer during curing, indirectly protecting the overall structural stability and bonding strength.

[0047] Comparative Example 1, using a PP (polypropylene) background film (non-PET), showed a peel strength of only 93 N / 50 mm even after corona treatment. This indicates that PET, due to its high polarity (containing ester groups), good ink adhesion, and superior bonding performance with polyurethane hot melt adhesive, is more suitable than PP as the color film substrate for LVT flooring, especially exhibiting stronger interlayer adhesion compatibility when laminated with polyolefin substrates. A complete structural design using a PET background film, combined with a second adhesive layer (polyurethane hot melt adhesive), and supplemented by a first adhesive layer and a UV protective layer (as in Example 1), achieved an interlayer peel strength of 120 N / 50 mm for the polyolefin-based LVT flooring, the highest among all test groups, demonstrating excellent interlayer bonding performance and long-term stability. Conversely, omitting the second adhesive layer (as in Example 4) drastically reduced the peel strength to 57 N / 50 mm, significantly increasing the risk of delamination. PET, compared to PP background film, has significant advantages in polarity matching and adhesive compatibility, making it the fundamental material choice for achieving high peel strength.

[0048] Therefore, from the perspective of peel strength, a key performance indicator, the design of this application, which uses a PET background film as the core and combines a dual adhesive system with a UV protective layer, can effectively solve the problems of easy peeling between layers and easy pattern detachment in traditional polyolefin LVT flooring, and has significant advantages in industrial applications.

Claims

1. A polyolefin-based LVT flooring, comprising, from bottom to top, a balancing layer (6), a polyolefin substrate layer (5), a color film layer (3), and a wear-resistant layer (1); characterized in that: The wear-resistant layer (1) includes a pre-made wear-resistant sheet (11) made of PET material and a UV wear-resistant layer (12) based on the pre-made wear-resistant sheet; the color film layer (3) includes a PET background film layer (31) and a pattern layer (32) based on the PET background film layer.

2. The polyolefin-based LVT flooring according to claim 1, characterized in that: The pattern layer (32) is obtained by printing or heat transfer on the PET background film layer (31).

3. The polyolefin-based LVT flooring according to claim 1, characterized in that: The polyolefin substrate layer (5) includes an integrally connected base substrate layer (51) and a modified substrate layer (52) located on the base substrate layer. The base substrate layer (51) is composed of the following components in parts by weight: Polyolefin resin 80~100, polyolefin elastomer 15~20, filler 10~30, stabilizer 2~5, processing aid 2~5; The modified substrate layer (52) is composed of the following components in parts by weight: The mixture comprises 40-60 parts polyolefin resin, 20-40 parts polyolefin graft-modified resin, 15-20 parts polyolefin elastomer, 10-20 parts filler, 2-5 parts modified filler, 2-5 parts stabilizer, and 2-5 parts processing aid; the modified filler is nano-silica treated with silane coupling agent.

4. The polyolefin-based LVT flooring according to claim 1, characterized in that: The color filter layer (3) includes a UV protection layer (33) disposed on the surface of the pattern layer (32).

5. A polyolefin-based LVT flooring according to claim 4, characterized in that: It also includes a first adhesive layer (2) disposed between the UV protective layer (33) and the prefabricated abrasion-resistant sheet (11).

6. The polyolefin-based LVT flooring according to claim 5, characterized in that: It also includes a second adhesive layer (4) disposed between the modified substrate layer (52) and the PET background film layer (31).

7. A polyolefin-based LVT flooring according to claim 1 or 2, characterized in that: The pattern layer (32) is a wood grain pattern layer.

8. A method for preparing the polyolefin-based LVT flooring according to any one of claims 1 to 7, comprising the following steps: S1. A polyolefin substrate layer (5) is provided with a balancing layer (6) on the back and a PET background film layer (31) on the decorative surface. S2. A pattern layer (32) is formed on the PET background film layer (31) by printing or heat transfer. S3. Spray / roll coat UV resin onto the patterned layer (32), and then cure it with UV-A band light to produce a UV protective layer (33) with a thickness of 10~50μm. S4. Spray / roll-coat the first adhesive onto the UV protective layer (33); S5. The PET pre-made abrasion-resistant sheet (11) is attached to the color film layer (3). S6. Spray / roll coat UV resin onto the PET pre-made wear-resistant sheet (11), and then cure it with UV-A band light to produce a UV wear-resistant layer (12) with a thickness of more than 100μm.

9. The preparation method according to claim 8, characterized in that, Step S1 is as follows: S11. The first resin composition for forming the base substrate layer (51) is fed into the first main extruder; S12, The second resin composition for forming the modified substrate layer (52) is fed into the second main extruder; S13. The first resin composition and the second resin composition are extruded from the first co-extrusion die by the first main extruder and the second main extruder respectively to obtain the polyolefin substrate layer (5). S14. Pass the polyolefin substrate layer (5) into the main channel of the second co-extrusion die; S15. Using a first auxiliary extruder, the third resin composition used to form the balance layer (6) is melt-extruded into the first side channel of the second co-extrusion die; S16. Using a second auxiliary extruder, the polyurethane hot melt adhesive used to form the second adhesive layer (4) is melted and extruded into the second side channel of the second co-extrusion die; S17. The third resin composition and polyurethane hot melt adhesive are extruded from the second co-extrusion die by the first auxiliary extruder and the second auxiliary extruder respectively, to obtain a polyolefin substrate layer (5) with a balance layer (6) on the back and a second adhesive layer (4) on the decorative surface. S18. The polyolefin substrate layer (5) prepared in step S17 is hot-pressed together with the PET background film layer (31) through the second adhesive layer (4) to obtain the polyolefin substrate layer (5) with a balancing layer (6) on the back and a PET background film layer (31) on the decorative surface.

10. The preparation method according to claim 8, characterized in that, Step S1 is as follows: S11. The first resin composition for forming the base substrate layer (51) is fed into the first main extruder; S12, The second resin composition for forming the modified substrate layer (52) is fed into the second main extruder; S13. The first resin composition and the second resin composition are extruded from the first co-extrusion die by the first main extruder and the second main extruder respectively to obtain the polyolefin substrate layer (5). S14. Pass the polyolefin substrate layer (5) into the main channel of the second co-extrusion die; S15. Using a first auxiliary extruder, the third resin composition used to form the balance layer (6) is melt-extruded into the first side channel of the second co-extrusion die; S16. Using a second auxiliary extruder, the polyurethane hot melt adhesive used to form the second adhesive layer (4) is melted and extruded into the second side channel of the second co-extrusion die; S17. Using a third auxiliary extruder, PET resin for forming a PET background film layer (31) is melted and extruded into the third side channel of the second co-extrusion die; S18. The third resin composition, polyurethane hot melt adhesive and PET resin are extruded from the second co-extrusion die through the first auxiliary extruder, the second auxiliary extruder and the third auxiliary extruder respectively, to obtain the polyolefin substrate layer (5) with a balance layer (6) on the back and a PET background film layer (31) on the decorative surface.

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