Fireproof and flame-retardant synthetic resin tile and method for manufacturing the same

Abstract

This invention discloses a fire-retardant synthetic resin tile and its preparation method, relating to the technical field of synthetic resin tiles. A synthetic resin tile includes a surface layer, a first toughening layer, a flame-retardant skeleton layer, and a second toughening layer arranged sequentially. The flame-retardant skeleton layer comprises flame-retardant chopped fibers and a composite smoke suppressant. By combining the flame-retardant chopped fibers with the composite smoke suppressant, not only is the flame-retardant performance of the flame-retardant skeleton layer improved, but the mechanical strength of the flame-retardant skeleton layer is also enhanced through fiber reinforcement. Furthermore, the flame-retardant skeleton layer, together with the first and second toughening layers, forms a multi-layered composite structure, resulting in a synthetic resin tile that not only possesses excellent flame-retardant and smoke-suppressing effects but also high mechanical strength.

Description

Technical Field

[0001] This invention relates to the technical field of synthetic resin tiles, and in particular to a fire-retardant synthetic resin tile and its preparation method. Background Technology

[0002] Synthetic resin roofing tiles are lightweight roofing materials made primarily of resins such as polyvinyl chloride (PVC), acrylonitrile-styrene-acrylate copolymer (ASA), or polycarbonate (PC) through co-extrusion or lamination processes. Compared to traditional ceramic tiles, metal tiles, and glazed tiles, they offer advantages such as lightweight, corrosion resistance, impact resistance, good color stability, and easy installation. They are now widely used in new rural construction, flat-to-slope roof conversion projects, scenic area decoration, and rural old house renovation.

[0003] Currently, most synthetic resin tiles on the market are made of PVC as the main raw material. Although PVC molecules contain chlorine, which can absorb some heat during combustion and has a self-extinguishing effect, the flame retardancy of ordinary PVC is still insufficient. It is a flammable material and releases a lot of black smoke and harmful gases during combustion. Its environmental performance is poor and it is difficult to meet the increasingly stringent fire safety requirements for buildings.

[0004] To improve the flame retardant properties of PVC-based synthetic resin tiles, the commonly used technique is to add flame retardants, such as inorganic combustion improvers or halogenated flame retardants. However, traditional inorganic flame retardants, such as aluminum hydroxide and magnesium hydroxide, have low flame retardant efficiency, requiring high dosages to meet building fire safety requirements. This not only significantly increases material costs but also reduces the flexibility and increases the brittleness of the resin tiles, making them prone to cracking under wind, snow, or hail impacts. Furthermore, excessive filling can affect the processing flowability of the synthetic resin tiles, making them difficult to manufacture. While adding highly efficient halogenated flame retardants can achieve good flame retardant effects with smaller dosages, halogenated flame retardants not only fail to reduce the amount of smoke produced when PVC resin tiles burn but also release large amounts of hydrogen halide fumes, posing certain environmental and health risks. Therefore, how to synergistically improve the flame retardant rating of synthetic resin tiles, maintain high mechanical strength and flexibility, and reduce smoke emissions with limited flame retardant dosages has become a critical technical bottleneck that the industry urgently needs to overcome. Summary of the Invention

[0005] In order to improve the flame retardant properties of synthetic resin tiles, balance their flame retardant effect and mechanical strength, and reduce the amount of smoke generated when the resin tiles are burning, this application provides a fire-retardant synthetic resin tile and its preparation method.

[0006] Firstly, the synthetic resin tile provided in this application adopts the following technical solution:

[0007] A synthetic resin tile includes a surface layer, a first toughness layer, a flame-retardant skeleton layer and a second toughness layer stacked in sequence, wherein the surface layer is formed by hot pressing and bonding ASA film onto the surface of the first toughness layer, and the first toughness layer, the flame-retardant skeleton layer and the second toughness layer are extruded together by a multi-layer co-extrusion process.

[0008] Both the first toughening layer and the second toughening layer are formed by melt extrusion of a toughening masterbatch, which comprises the following raw materials in parts by weight:

[0009] 100 parts PVC resin powder, 4.5-6 parts calcium-zinc stabilizer, 2-4 parts ACR impact modifier, 3-5 parts CPE, 0.8-1.2 parts stearic acid, 0.3-0.48 parts antioxidant, 2-3 parts titanium dioxide, and 10-15 parts heavy calcium carbonate;

[0010] The flame-retardant skeleton layer is formed by melt extrusion of flame-retardant masterbatch, which includes the following raw materials by weight: 100 parts PVC resin powder, 5-6.5 parts calcium zinc stabilizer, 6-8 parts CPE, 1-1.2 parts stearic acid, 0.8-1 parts PE wax, 10-16 parts flame-retardant chopped fiber, 6-8 parts composite smoke suppressant, and 30-40 parts heavy calcium carbonate;

[0011] Specifically, the flame-retardant chopped fibers are prepared by coating the surface of alkali-free glass fibers with zinc hydroxystannate sol, and then cutting them short after drying and curing; the composite smoke suppressant is a mixture of at least one of antimony trioxide, molybdenum trioxide or ammonium molybdate and zinc borate.

[0012] By adopting the above technical solution, flame-retardant chopped fibers are prepared by coating alkali-free glass fibers with zinc hydroxystannate sol. The zinc hydroxystannate coated on the surface of the alkali-free glass fibers can be fully dispersed in PVC along with the flame-retardant chopped fibers. Combined with a uniformly dispersed composite smoke suppressant, this not only significantly improves the flame-retardant performance of synthetic resin tiles, but also enhances the mechanical strength of the flame-retardant skeleton layer through the fiber reinforcement effect of the flame-retardant chopped fibers. In addition, by sequentially stacking the flame-retardant skeleton layer with the first toughening layer and the second toughening layer to form a multi-layer composite structure, the toughness and low-temperature impact resistance of the synthetic resin tiles can be effectively improved. This balances the relationship between the flame-retardant performance and mechanical strength of the synthetic resin tiles, achieving a superior overall performance with both excellent flame-retardant and smoke-suppressing effects and high mechanical strength.

[0013] Optionally, the method for preparing the flame-retardant chopped fibers includes the following steps:

[0014] A1. First, soak and clean the alkali-free glass fiber with anhydrous ethanol, dry it, then immerse the alkali-free glass fiber in an acidic solution, heat and continuously stir the reaction, take it out, soak and clean it multiple times with deionized water until the cleaning solution is neutral, and dry it to obtain acid-etched glass fiber.

[0015] A2. Weigh out zinc chloride and tin tetrachloride separately, mix them thoroughly, add them to deionized water, stir until completely dissolved, then continue stirring and slowly add sodium hydroxide solution, controlling the pH value within the range of 8.0-8.5, and continue stirring for 2-3 hours to obtain zinc hydroxystannate sol.

[0016] A3. Heat the zinc hydroxystannate sol to 60-70℃, then introduce and immerse the acid-etched glass fiber obtained in step A1 into the zinc hydroxystannate sol. After soaking for 3-5 minutes, pull it out at a uniform speed and air dry it with hot air. Repeat the soaking and air drying at least 3 times. Finally, pull it into an oven and heat it to 150-160℃ and dry and cure it for 2-3 hours. After taking it out, cool it and cut it into shorter pieces to obtain the flame-retardant short chopped fiber.

[0017] Optionally, in step A2 of the method for preparing flame-retardant chopped fibers, the molar ratio of zinc chloride to tin tetrachloride is 1:(0.75-0.9), and the zinc chloride is added to deionized water at an addition concentration of 1-1.5 mol / L.

[0018] Optionally, in step A3 of the flame-retardant chopped fiber preparation method, the mass ratio of the zinc hydroxystannate sol to the acid-etched glass fiber is 1:(0.5-0.8).

[0019] By adopting the above technical solution, a flame-retardant short fiber with both good flame-retardant effect and fiber reinforcement can be obtained. This is beneficial to improve the flame-retardant performance of synthetic resin tiles while increasing their mechanical strength, thus achieving a balance between the flame-retardant performance and mechanical strength of synthetic resin tiles.

[0020] Optionally, the flame-retardant chopped fibers have a length of 4-6 mm.

[0021] By adopting the above technical solution, it is possible to prevent the entanglement and overlap of fibers and the formation of local agglomeration areas caused by excessive fiber length, while ensuring that the flame-retardant chopped fibers have a certain fiber reinforcement effect. This helps to reduce stress concentration points in the flame-retardant skeleton layer, thereby improving the toughness and impact resistance of synthetic resin tiles.

[0022] Optionally, the composite smoke suppressant is a mixture of zinc borate, antimony trioxide, and molybdenum trioxide.

[0023] By adopting the above technical solution, a good smoke suppression system can be formed in conjunction with flame-retardant chopped fibers, which is beneficial to improving the flame-retardant and smoke-suppressing performance of synthetic resin tiles.

[0024] Optionally, the heavy calcium carbonate in both the toughening masterbatch and the flame retardant masterbatch needs to undergo surface modification treatment before being added together. The surface modification treatment of the heavy calcium carbonate includes the following steps:

[0025] Heavy calcium carbonate was added to an ethanol aqueous solution at a rate of 20 wt%, and then ultrasonically dispersed. The solution was heated to 75-80°C, and then titanate coupling agent and ammonium polyphosphate were added. The mixture was stirred continuously for 2-3 hours, filtered under reduced pressure, and dried under vacuum to obtain surface-modified heavy calcium carbonate.

[0026] Optionally, the mass ratio of the heavy calcium carbonate, the titanate coupling agent, and the ammonium polyphosphate is 100:(2-3):(12-18).

[0027] By adopting the above technical solution, not only can the surface properties of heavy calcium carbonate be improved, allowing it to be fully dispersed and combined in PVC, which is beneficial to further improving the mechanical properties of synthetic resin tiles; but also ammonium polyphosphate with flame-retardant effect can be introduced into the surface of heavy calcium carbonate. As the heavy calcium carbonate is fully dispersed, the ammonium polyphosphate can be uniformly dispersed in the synthetic resin tiles, which is beneficial to further improving the overall flame-retardant performance of synthetic resin tiles.

[0028] Secondly, the method for preparing a synthetic resin tile provided in this application adopts the following technical solution:

[0029] A method for preparing synthetic resin tiles includes the following steps:

[0030] S1. Weigh the tough PVC masterbatch and flame-retardant PVC masterbatch separately and dry them thoroughly. Then, send them to the first extruder, the second extruder and the third extruder respectively. They are extruded and mixed, and then sent to the layer distributor through their respective channels. They are then collected into the main channel and extruded into the die head to form a three-layer tile body arranged in the form of a first tough layer, a flame-retardant skeleton layer and a second tough layer. S2. Apply an ASA film to the surface of the three-layer tile body obtained in step S1 by hot pressing rollers. Then, send it into a shaping mold for wave pressing. After natural cooling, it is pulled, trimmed and cut to a fixed length to obtain the synthetic resin tile.

[0031] By adopting the above technical solution, the preparation method is simple. A multi-layer co-extrusion process can fully bond the first toughening layer, the flame-retardant skeleton layer, and the second toughening layer. Furthermore, a hot-pressing composite process can cover the surface of the first toughening layer with a highly weather-resistant ASA film, which improves the weather resistance and service life of the synthetic resin tile. In addition, the required equipment investment is relatively small, which is beneficial for the factory to carry out mass production of synthetic resin tiles.

[0032] Optionally, the overall thickness of the co-extruded first toughness layer, the flame-retardant skeleton layer and the second toughness layer is 2-3.5 mm, and the thickness ratio of the first toughness layer, the flame-retardant skeleton layer and the second toughness layer is 1:(2.5-3):(1-1.5).

[0033] By adopting the above technical solution, not only can the flame retardant and mechanical properties of synthetic resin tiles be effectively balanced, but also the overall weight of synthetic resin tiles at this thickness is appropriate, neither too heavy nor too light, making them suitable for roofing construction of various load-bearing structures and highly versatile.

[0034] In summary, the technical solution of this application has at least one of the following beneficial effects:

[0035] 1. By using zinc hydroxystannate sol to coat alkali-free glass fibers to obtain flame-retardant chopped fibers, and combining them with uniformly dispersed composite smoke suppressants, the flame-retardant properties of synthetic resin tiles can be significantly improved. Furthermore, the mechanical strength of the flame-retardant skeleton layer can be enhanced through the fiber reinforcement effect of the flame-retardant chopped fibers.

[0036] 2. Synthetic resin tiles with a multi-layer composite structure formed by sequentially stacking a flame-retardant skeleton layer, a first toughening layer, and a second toughening layer can effectively improve the toughness and low-temperature impact resistance of synthetic resin tiles.

[0037] 3. By controlling the length of flame-retardant chopped fibers within the range of 4-6mm, it is possible to prevent fiber entanglement, overlap, and the formation of local agglomeration areas due to excessive fiber length, while ensuring that the flame-retardant chopped fibers have a certain fiber reinforcement effect. This helps to reduce stress concentration points in the flame-retardant skeleton layer, thereby improving the toughness and impact resistance of synthetic resin tiles.

[0038] 4. By using titanate coupling agents and ammonium polyphosphate to modify the surface of heavy calcium carbonate, not only can the surface properties of heavy calcium carbonate be improved, allowing it to be fully dispersed and combined in PVC, which is beneficial to further improving the mechanical properties of synthetic resin tiles; but also, ammonium polyphosphate with flame-retardant effect can be introduced into the surface of heavy calcium carbonate. As the heavy calcium carbonate is fully dispersed, the ammonium polyphosphate can be uniformly dispersed in the synthetic resin tiles, which is beneficial to further improving the overall flame-retardant performance of synthetic resin tiles. Attached Figure Description

[0039] Figure 1 This is a cross-sectional view of a synthetic resin tile according to Embodiment 1 of this application.

[0040] Figure 2 This is a cross-sectional view of a synthetic resin tile in Comparative Example 4 of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Surface layer; 2. First toughness layer; 3. Flame-retardant skeleton layer; 4. Second toughness layer. Detailed Implementation

[0043] The present application will be further described in detail below with reference to the accompanying drawings, preparation examples, embodiments and comparative examples.

[0044] The ASA film specifically selected was the PVC-specific ultra-weather-resistant ASA film from Shanghai Hongjingyin Industrial Co., Ltd., with a thickness of 0.08mm.

[0045] The PVC resin powder was specifically purchased from SG-5 PVC resin powder in Erdos.

[0046] The ACR impact modifier was specifically purchased from Kanekazuchi, Japan, with the brand name PA-20.

[0047] The heavy calcium carbonate was purchased from Dongguan Wuxin New Materials, specifically 1000 mesh heavy calcium carbonate.

[0048] The titanium dioxide was purchased from Panzhihua Iron and Steel Group Co., Ltd., and the grade was R-248 rutile titanium dioxide.

[0049] The titanate coupling agent was purchased from Nengde New Materials, specifically the new alkoxy titanate with the brand name TCA-L38.

[0050] The glass fiber was purchased from Jiujiang Lianfeng Glass Fiber Co., Ltd., specifically 100g alkali-free glass fiber of model 2116.

[0051] Preparation Example

[0052]

Preparation Example 1-1

[0053] A flame-retardant chopped fiber is prepared by the following method:

[0054] A1. First, thoroughly soak and clean the alkali-free glass fiber with anhydrous ethanol. After drying, immerse the alkali-free glass fiber in an acidic solution, which is a 5% hydrochloric acid aqueous solution. Heat to 82°C and stir continuously for 30 minutes. Remove the fiber and soak and clean it multiple times with deionized water until the cleaning solution is neutral. After drying, acid-etched glass fiber is obtained.

[0055] A2. Weigh out 10 mol of zinc chloride and 7.5 mol of tin tetrachloride, mix them thoroughly, and add them to 10 L of deionized water. Stir until completely dissolved, then continue stirring and slowly add sodium hydroxide solution, controlling the pH value within the range of 8.0-8.5. Continue stirring and react for 2 hours to obtain zinc hydroxystannate sol.

[0056] A3. Heat the zinc hydroxystannate sol to 60°C, then take 5 kg of the acid-etched glass fiber obtained in step A1 and immerse it in 10 kg of zinc hydroxystannate sol. After soaking for 5 minutes, pull it out at a uniform speed and air dry it with hot air at 75°C. Repeat the soaking and air drying process 3 times. Finally, pull it into an oven and heat it to 150°C and dry and cure it for 3 hours. After taking it out, cool it and cut it to a length of 4-6 mm to obtain the flame-retardant short chopped fiber.

[0057]

Preparation Examples 1-2

[0058] A flame-retardant chopped fiber is prepared by the following method:

[0059] A1. First, thoroughly soak and clean the alkali-free glass fiber with anhydrous ethanol. After drying, immerse the alkali-free glass fiber in an acidic solution, which is a 5% hydrochloric acid aqueous solution. Heat to 85°C and stir continuously for 20 minutes. Remove the fiber and soak and clean it multiple times with deionized water until the cleaning solution is neutral. After drying, acid-etched glass fiber is obtained.

[0060] A2. Weigh out 15 mol of zinc chloride and 9 mol of tin tetrachloride, mix them thoroughly, and add them to 10 L of deionized water. Stir until completely dissolved, then continue stirring and slowly add sodium hydroxide solution, controlling the pH value within the range of 8.0-8.5. Continue stirring and react for 2 hours to obtain zinc hydroxystannate sol.

[0061] A3. Heat the zinc hydroxystannate sol to 70°C, then take 8 kg of the acid-etched glass fiber obtained in step A1 and immerse it in 10 kg of zinc hydroxystannate sol. After soaking for 3 minutes, pull it out at a uniform speed and air dry it with hot air at 80°C. Repeat the soaking and air drying process 3 times. Finally, pull it into an oven and heat it to 160°C and dry and cure it for 2 hours. After taking it out, cool it and cut it to a length of 4-6 mm to obtain the flame-retardant short chopped fiber.

[0062]

Preparation Examples 1-3

[0063] A flame-retardant chopped fiber, which differs from [Preparation Example 1] in that step S3 of the preparation method is different.

[0064] In this preparation example, in step S3, the acid-etched glass fiber is only immersed in zinc hydroxystannate sol and air-dried once.

[0065]

Preparation Examples 1-4

[0066] A flame-retardant chopped fiber, which differs from [Preparation Example 1] in that the length of the flame-retardant chopped fiber is different.

[0067] In this preparation example, the flame-retardant chopped fibers are cut to a length of 10-12 mm.

[0068]

Preparation Example 2-1

[0069] A surface-modified heavy calcium carbonate, the surface modification of which includes the following steps:

[0070] 50 kg of heavy calcium carbonate was added to a 75% ethanol aqueous solution at a concentration of 20 wt%, and the mixture was fully ultrasonically dispersed and heated to 75°C. Then, 1.5 kg of titanate coupling agent and 9 kg of ammonium polyphosphate were added, and the mixture was stirred continuously for 3 hours. The mixture was then filtered under reduced pressure and dried under vacuum to obtain surface-modified heavy calcium carbonate.

[0071]

Preparation Example 2-2

[0072] A surface-modified heavy calcium carbonate, the surface modification of which includes the following steps:

[0073] 50 kg of heavy calcium carbonate was added to a 75% ethanol aqueous solution at a concentration of 20 wt%, and the mixture was fully ultrasonically dispersed and heated to 80°C. Then, 1 kg of titanate coupling agent and 6 kg of ammonium polyphosphate were added, and the mixture was stirred continuously for 2 h. The mixture was then filtered under reduced pressure and dried under vacuum to obtain the surface-modified heavy calcium carbonate.

[0074] Example

[0075]

Example 1

[0076] A synthetic resin tile, as described above Figure 1 It includes a surface layer 1, a first toughness layer 2, a flame-retardant skeleton layer 3, and a second toughness layer 4, which are stacked in sequence. The surface layer 1 is formed by applying an ASA film to the surface of the first toughness layer 2 through a hot-pressing composite process. The first toughness layer 2, the flame-retardant skeleton layer 3, and the second toughness layer 4 are extruded together through a multi-layer co-extrusion process.

[0077] The first toughening layer 2 and the second toughening layer 4 are both formed by melt extrusion of toughening masterbatch. In this embodiment, the toughening masterbatch includes the following raw materials: 100kg PVC resin powder, 4.5kg calcium zinc stabilizer, 2kg ACR impact agent, 5kg CPE, 0.8 parts stearic acid, 0.3kg antioxidant, 3kg titanium dioxide and 10kg heavy calcium carbonate.

[0078] Specifically, the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2, that is, the antioxidant includes 0.1 kg of antioxidant 1010 and 0.2 kg of antioxidant 168.

[0079] The flame-retardant skeleton layer 3 is formed by melt extrusion of flame-retardant masterbatch. In this embodiment, the flame-retardant masterbatch includes the following raw materials: 100 parts of PVC resin powder, 5 kg of calcium zinc stabilizer, 6 kg of CPE, 1 kg of stearic acid, 0.8 kg of PE wax, 16 kg of flame-retardant chopped fiber, 8 kg of composite smoke suppressant and 30 kg of heavy calcium carbonate.

[0080] The flame-retardant chopped fibers were specifically prepared according to [Preparation Example 1-1]. The composite smoke suppressant was specifically a mixture of zinc borate and molybdenum trioxide in a 4:1 mass ratio, i.e., the composite smoke suppressant consisted of 6.4 kg of zinc borate and 1.6 kg of molybdenum trioxide.

[0081] A method for preparing synthetic resin tiles includes the following steps:

[0082] S1. Weigh the toughness masterbatch and flame retardant masterbatch by mass, mix them thoroughly, and then dry them. Then send them to the first extruder, the second extruder, and the third extruder respectively. After extrusion and mixing, they are collected into the main channel through the layer distributor and co-extruded into the die head to form a three-layer tile body arranged in the form of the first toughness layer 2, the flame retardant skeleton layer 3, and the second toughness layer 4.

[0083] S2. The ASA film is hot-pressed onto the surface of the three-layer tile body obtained in step S1 using a hot press roller. Then, it is fed into a shaping mold for wave pressing and molding. After natural cooling, it is pulled, trimmed, and cut to a fixed length to obtain the synthetic resin tile.

[0084] In this embodiment, the three-layer tile body in step S1 is extruded with an overall thickness of 3mm, wherein the thickness of the first toughening layer 2 is 0.6mm, the thickness of the flame-retardant skeleton layer 3 is 1.5mm, and the thickness of the second toughening layer 4 is 0.9mm.

[0085]

Example 2

[0086] A synthetic resin tile differs from [Example 1] in that the raw materials and thicknesses of the first toughening layer 2, the flame-retardant skeleton layer 3, and the second toughening layer 4 are different.

[0087] The first toughening layer 2 and the second toughening layer 4 are both formed by melt extrusion of toughening masterbatch. In this embodiment, the toughening masterbatch includes the following raw materials: 100 parts PVC resin powder, 6 parts calcium zinc stabilizer, 4 parts ACR impact agent, 3 parts CPE, 1.2 parts stearic acid, 0.48 parts antioxidant, 2 parts titanium dioxide and 15 parts heavy calcium carbonate.

[0088] Specifically, the antioxidant is a mixture of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:3, that is, the antioxidant includes 0.12 kg of antioxidant 1010 and 0.36 kg of antioxidant 168.

[0089] The flame-retardant skeleton layer 3 is formed by melt extrusion of flame-retardant masterbatch. In this embodiment, the flame-retardant masterbatch includes the following raw materials: 100 parts PVC resin powder, 6.5 parts calcium zinc stabilizer, 8 parts CPE, 1.2 parts stearic acid, 1 part PE wax, 10 parts flame-retardant chopped fiber, 6 parts composite smoke suppressant and 40 parts light calcium carbonate.

[0090] The flame-retardant chopped fibers were specifically prepared according to [Preparation Examples 1-2]. The composite smoke suppressant was specifically a mixture of zinc borate and ammonium molybdate in a 5:1 mass ratio, i.e., the composite smoke suppressant consisted of 5 kg of zinc borate and 1 kg of ammonium molybdate.

[0091] In this embodiment, the heavy calcium carbonate used in both the toughening masterbatch and the flame retardant masterbatch is surface-modified heavy calcium carbonate. Specifically, in this embodiment, the surface-modified heavy calcium carbonate is prepared according to [Preparation Example 2-1].

[0092] In this embodiment, the three-layer tile body in step S1 is extruded with an overall thickness of 3mm, wherein the thickness of the first toughening layer 2 is 0.6mm, the thickness of the flame-retardant skeleton layer 3 is 1.8mm, and the thickness of the second toughening layer 4 is 0.6mm.

[0093]

Example 3

[0094] A synthetic resin tile, which differs from [Example 1] in that the flame-retardant skeleton layer 3 is different.

[0095] In this embodiment, the flame-retardant chopped fibers used in the flame-retardant masterbatch are specifically prepared from [Preparation Examples 1-3].

[0096]

Example 4

[0097] A synthetic resin tile, which differs from [Example 1] in that the flame-retardant skeleton layer 3 is different.

[0098] In this embodiment, the flame-retardant chopped fibers used in the flame-retardant masterbatch are specifically prepared from [Preparation Examples 1-4].

[0099]

Example 5

[0100] A synthetic resin tile, which differs from [Example 1] in that the flame-retardant skeleton layer 3 is different.

[0101] In this embodiment, the composite smoke suppressant used in the flame retardant masterbatch is specifically a mixture of zinc borate and antimony trioxide, wherein the mass ratio of zinc borate to antimony trioxide is 3:1, that is, the composite smoke suppressant includes 6 kg of zinc borate and 2 kg of antimony trioxide.

[0102]

Example 6

[0103] A synthetic resin tile, which differs from [Example 1] in that the flame-retardant skeleton layer 3 is different.

[0104] In this embodiment, the composite smoke suppressant used in the flame retardant masterbatch is a mixture of zinc borate, antimony trioxide and molybdenum trioxide, wherein the mass ratio of zinc borate, antimony trioxide and molybdenum trioxide is 12:3:1, that is, the composite smoke suppressant includes 6 kg of zinc borate, 1.5 kg of antimony trioxide and 0.5 kg of molybdenum trioxide.

[0105]

Example 7

[0106] A synthetic resin tile differs from [Example 6] in that the first toughening layer 2, the flame-retardant skeleton layer 3, and the second toughening layer 4 are different.

[0107] In this embodiment, the heavy calcium carbonate used in both the toughening masterbatch and the flame retardant masterbatch is surface-modified heavy calcium carbonate. Specifically, the surface-modified heavy calcium carbonate is prepared according to [Preparation Example 2-2].

[0108] Comparative Example

[0109] Comparative Example 1

[0110] A synthetic resin tile, which differs from [Example 1] in that the flame-retardant skeleton layer 3 is different.

[0111] In this comparative example, no flame-retardant chopped fibers were added to the flame-retardant masterbatch.

[0112] Comparative Example 2

[0113] A synthetic resin tile, which differs from [Example 1] in that the flame-retardant skeleton layer 3 is different.

[0114] In this comparative example, the flame-retardant chopped fibers used in the flame-retardant masterbatch were replaced with equal amounts of alkali-free glass fibers.

[0115] Comparative Example 3

[0116] A synthetic resin tile, which differs from [Example 1] in that the flame-retardant skeleton layer 3 is different.

[0117] In this comparative example, no composite smoke suppressant was added to the flame retardant masterbatch.

[0118] Comparative Example 4

[0119] A synthetic resin tile differs from [Example 1] in that its overall structure is different.

[0120] In this comparative example, refer to Figure 2 The synthetic resin tile consists only of a surface layer 1 and a flame-retardant skeleton layer 3 stacked sequentially. The preparation of both the surface layer 1 and the flame-retardant skeleton layer 3 is the same as in [Example 1], and the thickness of the flame-retardant skeleton layer 3 is 3 mm.

[0121] Performance test data

[0122] 1. Limiting oxygen index: The limiting oxygen index of the synthetic resin tiles prepared in each example and comparative example was tested according to Section 6.1 of "TCBMCA 007-2019 Synthetic Resin Tiles" and "GB / T2406.22009 Determination of Combustion Behavior by Oxygen Index Method for Plastics - Part 2: Room Temperature Test".

[0123] 2. Smoke density: Flame tests were conducted according to GB / T 8323.1-2008 Plastics Smoke Generation Part 1: Guidelines for Smoke Density Test Method and GB / T 8323.2-2008 Plastics Smoke Generation Part 2: Single Chamber Method for Determination of Smoke Density Test Method, and the smoke density rating (SDR) of the synthetic resin tiles prepared in each example and comparative example was recorded.

[0124] 3. Tensile strength: The tensile strength (MPa) and elongation at break (%) of the synthetic resin tiles prepared in each example and comparative example were tested according to Section 6.13 of "TCBMCA 007-2019 Synthetic Resin Tiles" and "GB / T1040.2-2022 Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics".

[0125] 4. Impact resistance: The low-temperature drop hammer impact test was conducted according to Section 6.8 of "TCBMCA 007-2019 Synthetic Resin Tiles", and the cracking conditions of the synthetic resin tiles prepared in each embodiment and comparative example were recorded.

[0126] Table 1. Partial Performance Tests of Synthetic Resin Tiles

[0127]

[0128] Based on Examples 1 and Comparative Examples 1-3, and the data in Table 1, it can be seen that using zinc hydroxystannate sol to coat alkali-free glass fibers to produce flame-retardant chopped fibers, and then combining these flame-retardant chopped fibers with a composite smoke suppressant, can significantly improve the flame-retardant performance of synthetic resin tiles. Furthermore, because the flame-retardant chopped fibers have a certain fiber reinforcement effect, they can also help maintain the high mechanical strength of the synthetic resin tiles, thus balancing the flame-retardant effect and mechanical strength. In addition, based on Examples 1 and Comparative Example 4, and the data in Table 1, it can be seen that when the overall structure of the synthetic resin tile consists only of the surface layer 1 and the flame-retardant skeleton layer 3, although the overall combustion oxygen index of the synthetic resin tile increases, the smoke density decreases, and the tensile strength also increases significantly, the overall toughness decreases significantly. Not only is the elongation at break significantly reduced, but the number of fractures in the low-temperature impact test also increases significantly. This demonstrates that the first toughening layer 2 and the second toughening layer 4 play an important role in the toughening and balancing effect of the synthetic resin tile.

[0129] Combining Examples 1 and 3 with the data in Table 1, it can be seen that when the number of times the alkali-free glass fibers are soaked and air-dried in the zinc hydroxystannate sol is reduced during the preparation of flame-retardant chopped fibers, the oxygen index of the subsequently produced synthetic resin tiles is significantly lower, and the smoke density is also increased, indicating a decrease in the flame-retardant performance of the synthetic resin tiles. This may be because repeatedly soaking the alkali-free glass fibers in the zinc hydroxystannate sol facilitates the full adhesion of zinc hydroxystannate to the alkali-free glass fibers, thereby effectively increasing the coating rate of zinc hydroxystannate on the surface of the alkali-free glass fibers. The higher the coating rate of zinc hydroxystannate on the surface of the added flame-retardant chopped fibers, i.e., the greater the proportion of zinc hydroxystannate, the better the flame-retardant performance of the synthetic resin tiles is improved through the uniform dispersion of the alkali-free glass fibers.

[0130] Combining Examples 1 and 4 with the data in Table 1, it can be seen that when the length of the flame-retardant chopped fibers used is in the range of 10-12 mm, compared with the length of the flame-retardant chopped fibers in the range of 4-6 mm, the elongation at break and the low-temperature impact resistance of the resulting synthetic resin tiles are significantly reduced, indicating that the toughness of the synthetic resin tiles is reduced at this time. This may be because when the length of the flame-retardant chopped fibers increases to 10-12 mm, during the extrusion of the flame-retardant skeleton layer 3 with a thickness of 1.5 mm, the longer flame-retardant chopped fibers are more likely to entangle and overlap between fibers, forming local agglomerates. These agglomerates not only cannot effectively transfer stress, but also become stress concentration points inside the material. Consequently, when the synthetic resin tile is subjected to tensile or impact loads, the stress will preferentially accumulate in the matrix around the agglomerates, making this part more prone to brittle fracture, thus exhibiting a decrease in elongation at break and an increase in the low-temperature impact fracture rate.

[0131] Combining Examples 1 and 5-6 with the data in Table 1, it can be seen that when the composite smoke suppressant in the flame-retardant skeleton layer 3 is a mixture of zinc borate, antimony trioxide, and molybdenum trioxide, the resulting synthetic resin tile exhibits superior flame retardancy compared to a mixture using only one of antimony trioxide or molybdenum trioxide mixed with zinc borate. This may be because the flame-retardant and smoke-suppressing mechanisms of antimony trioxide and molybdenum trioxide are different. In the smoke-suppressing system of the mixture of zinc borate, antimony trioxide, and molybdenum trioxide, the gas-phase free radical capture of antimony trioxide complements the condensed-phase physical barrier of zinc borate. Meanwhile, the catalytic charring effect of molybdenum trioxide enhances the charring effect of zinc borate and assists antimony trioxide in reducing the concentration of gaseous combustibles. This results in a synergistic cycle of "gas-phase blocking - condensed-phase protection - char layer strengthening" smoke-suppressing system in the flame-retardant skeleton layer 3, thus further improving the flame-retardant performance of the synthetic resin tile.

[0132] Based on Examples 6-7 and the data in Table 1, it can be seen that using surface-modified heavy calcium carbonate as a filler not only improves the flame retardant and smoke-suppressing properties of synthetic resin tiles, but also further enhances their tensile strength and fracture properties, resulting in superior overall performance. This is likely because surface modification of heavy calcium carbonate using titanate coupling agents and ammonium polyphosphate not only improves the surface properties of the heavy calcium carbonate, allowing it to disperse and bind fully in PVC, but also introduces flame-retardant ammonium polyphosphate onto the surface of the heavy calcium carbonate. Furthermore, with the full dispersion of the heavy calcium carbonate, the ammonium polyphosphate can improve the flame retardant and smoke-suppressing properties of the synthetic resin tiles through its own flame-retardant and smoke-suppressing effects, thus contributing to superior overall performance.

[0133] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A synthetic resin tile, characterized in that: It includes a surface layer (1), a first toughness layer (2), a flame-retardant skeleton layer (3) and a second toughness layer (4) stacked in sequence. The surface layer (1) is formed by hot-pressing composite of ASA film onto the surface of the first toughness layer (2). The first toughness layer (2), the flame-retardant skeleton layer (3) and the second toughness layer (4) are extruded together by multi-layer co-extrusion process. Both the first toughness layer (2) and the second toughness layer (4) are formed by melt extrusion of toughness masterbatch, which comprises the following raw materials in parts by weight: 100 parts PVC resin powder, 4.5-6 parts calcium-zinc stabilizer, 2-4 parts ACR impact modifier, 3-5 parts CPE, 0.8-1.2 parts stearic acid, 0.3-0.48 parts antioxidant, 2-3 parts titanium dioxide, and 10-15 parts heavy calcium carbonate; The flame-retardant skeleton layer (3) is formed by melt extrusion of flame-retardant masterbatch, which includes the following raw materials in parts by weight: 100 parts PVC resin powder, 5-6.5 parts calcium-zinc stabilizer, 6-8 parts CPE, 1-1.2 parts stearic acid, 0.8-1 part PE wax, 10-16 parts flame-retardant chopped fiber, 6-8 parts composite smoke suppressant, and 30-40 parts heavy calcium carbonate; Specifically, the flame-retardant chopped fibers are prepared by coating the surface of alkali-free glass fibers with zinc hydroxystannate sol, and then cutting them short after drying and curing; the composite smoke suppressant is a mixture of at least one of antimony trioxide, molybdenum trioxide or ammonium molybdate and zinc borate.

2. The synthetic resin tile according to claim 1, characterized in that: The method for preparing the flame-retardant chopped fiber includes the following steps: A1. First, soak and clean the alkali-free glass fiber with anhydrous ethanol, dry it, then immerse the alkali-free glass fiber in an acidic solution, heat and continuously stir the reaction, take it out, soak and clean it multiple times with deionized water until the cleaning solution is neutral, and dry it to obtain acid-etched glass fiber. A2. Weigh out zinc chloride and tin tetrachloride separately, mix them thoroughly, add them to deionized water, stir until completely dissolved, then continue stirring and slowly add sodium hydroxide solution, controlling the pH value within the range of 8.0-8.5, and continue stirring for 2-3 hours to obtain zinc hydroxystannate sol. A3. Heat the zinc hydroxystannate sol to 60-70℃, then introduce and immerse the acid-etched glass fiber obtained in step A1 into the zinc hydroxystannate sol. After soaking for 3-5 minutes, pull it out at a uniform speed and air dry it with hot air. Repeat the soaking and air drying at least 3 times. Finally, pull it into an oven and heat it to 150-160℃ and dry and cure it for 2-3 hours. After taking it out, cool it and cut it into shorter pieces to obtain the flame-retardant short chopped fiber.

3. The synthetic resin tile according to claim 2, characterized in that: In step A2 of the method for preparing flame-retardant chopped fibers, the molar ratio of zinc chloride to tin tetrachloride is 1:(0.75-0.9), and the zinc chloride is added to deionized water at a concentration of 1-1.5 mol / L.

4. A synthetic resin tile according to claim 3, characterized in that: In step A3 of the method for preparing flame-retardant chopped fibers, the mass ratio of the zinc hydroxystannate sol to the acid-etched glass fiber is 1:(0.5-0.8).

5. A synthetic resin tile according to claim 2, characterized in that: The flame-retardant chopped fibers have a length of 4-6 mm.

6. A synthetic resin tile according to claim 1, characterized in that: The composite smoke suppressant is a mixture of zinc borate, antimony trioxide, and molybdenum trioxide.

7. A synthetic resin tile according to claim 1, characterized in that: The heavy calcium carbonate in both the toughening masterbatch and the flame retardant masterbatch needs to undergo surface modification treatment before being added together. The surface modification treatment of the heavy calcium carbonate includes the following steps: Heavy calcium carbonate was added to an ethanol aqueous solution at a rate of 20 wt%, and then ultrasonically dispersed. The solution was heated to 75-80°C, and then titanate coupling agent and ammonium polyphosphate were added. The mixture was stirred continuously for 2-3 hours, filtered under reduced pressure, and dried under vacuum to obtain surface-modified heavy calcium carbonate.

8. A synthetic resin tile according to claim 7, characterized in that: The mass ratio of the heavy calcium carbonate, the titanate coupling agent, and the ammonium polyphosphate is 100:(2-3):(12-18).

9. A method for preparing synthetic resin tiles, used to prepare synthetic resin tiles as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Weigh the tough masterbatch and flame retardant masterbatch respectively and dry them thoroughly. Send them to the first extruder, the second extruder and the third extruder respectively. They are extruded and mixed respectively. Then they are sent to the layer distributor through their respective flow channels, converged into the main flow channel and entered the die head for co-extrusion to form a three-layer tile body arranged in the first tough layer (2), the flame retardant skeleton layer (3) and the second tough layer (4). S2. The ASA film is hot-pressed onto the surface of the three-layer tile body obtained in step S1 using a hot press roller. Then, it is sent into a shaping mold for wave pressing and molding. After natural cooling, it is pulled, trimmed, and cut to a fixed length in place to obtain the synthetic resin tile.

10. The method for preparing a synthetic resin tile according to claim 9, characterized in that: In step S1, the overall thickness of the three-layer tile body is 2-3.5mm, and the thickness ratio of the first toughness layer (2), the flame-retardant skeleton layer (3) and the second toughness layer (4) is 1:(2.5-3):(1-1.5).

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