High-strength heat-resistant flame-retardant floor base material based on regenerated PETG (polyethylene terephthalate glycol) and preparation method thereof

Abstract

The invention belongs to the technical field of PETG floors, and particularly relates to a regenerated PETG-based high-strength heat-resistant flame-retardant floor base material and a preparation method thereof. The floor base material is prepared from the regenerated PETG, the compatilizer, the chain extender, the lubricant, the anti-hydrolysis agent, the antioxidant, the modified diatomite and the calcium carbonate according to a specific ratio, has the advantages of low warpage, low shrinkage, high tensile bending strength, good heat resistance and flame retardancy and the like, and also has the advantage of low density and light weight. According to the floor base material and the floor, the resource utilization field of the regenerated PETG is well expanded, and the performance of the regenerated PETG floor base material and the performance of the floor are ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of PETG floor, and particularly relates to a high-strength heat-resistant flame-retardant floor substrate based on recycled PETG and a preparation method thereof. BACKGROUND

[0002] Floor is a commonly used indoor decoration material. Traditional floors mostly adopt solid wood floors and PVC floors, which have problems of large resource consumption, heavy environmental burden or difficult recycling, and have been difficult to meet the increasingly stringent environmental protection requirements. PETG (polyethylene terephthalate-1, 4-cyclohexane dimethyl ester) is a transparent, non-crystalline copolyester, which has rarely been used as a floor substrate layer before. Only a few units in China have carried out research and development of PETG floor, but there are many shortcomings such as the need for a large number of material composites (for example, patent document CN112009060A) or the need to jointly plate with other plastic substrates (for example, patent document CN119708772A), and the floor has many performance deficiencies, and the selection of floor substrate ingredients is difficult.

[0003] At the same time, improper disposal of a large amount of PETG waste (mainly from food packaging, medical devices and other fields) not only causes resource waste, but also causes serious environmental problems. This makes it extremely economically and socially beneficial to develop floor substrates and floors based on recycled PETG, especially floors that do not need to be jointly plated with other plastic substrates or floors that do not need to be composed of a large number of materials.

[0004] Although melt regranulation as a basic process for PETG recycling has become increasingly mature, the simplified physical recycling method and mature equipment system not only greatly reduce production costs, but also maintain the basic performance of the material. This makes it the most economical and practical technical choice for the large-scale production of recycled PETG floor, and lays a solid foundation for the widespread application of recycled materials. However, the research and development of floor substrates and floors based on recycled PETG, especially floors that do not need to be jointly plated with other plastic substrates or floors that do not need to be composed of a large number of materials, is still a technical blank in the field. SUMMARY

[0005] In view of the above problems, the purpose of the present application is to provide a high-strength heat-resistant flame-retardant floor substrate based on recycled PETG and a preparation method thereof, so as to provide a floor substrate and floor based on recycled PETG with superior performance. The technical solution of the present application is as follows: First, this invention provides a high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG. The flooring substrate is made of recycled PETG as the main material and auxiliary materials, including compatibilizers, chain extenders, lubricants, anti-hydrolysis agents, modified diatomaceous earth, and calcium carbonate. The weight ratio of modified diatomaceous earth to calcium carbonate is (1~3):(2~4). The total amount of modified diatomaceous earth and calcium carbonate to the weight ratio of recycled PETG is 150:(60~100). The modified diatomaceous earth is silane coupling agent modified diatomaceous earth.

[0006] Preferably, the silane coupling agent is selected from KH570 and KH590.

[0007] Preferably, the auxiliary material further includes an antioxidant; the amount of antioxidant used is in a weight ratio of (1~2):(60~100) of recycled PETG. More preferably, the antioxidant is selected from one or more of antioxidant 1010, antioxidant 5057, antioxidant 626, and di(tetrazolium thiopropionate).

[0008] Preferably, the compatibilizer is selected from one or more of EMA-g-GMA (ethylene-methyl acrylate grafted glycidyl acrylate), SEBS-g-GMA (styrene-ethylene-butene-styrene block copolymer grafted glycidyl methacrylate), POE-g-GMA (polyolefin elastomer grafted glycidyl methacrylate), ABS-g-MAH (acrylonitrile-butadiene-styrene copolymer grafted maleic anhydride), and POE-g-MAH (polyolefin elastomer grafted maleic anhydride); the weight ratio of the compatibilizer to recycled PETG is (5~10):(60~100).

[0009] Preferably, the chain extender is selected from one or more of styrene-glycidyl methacrylate, 2,2-(1,3-phenylene)-bis(2-oxazoline), triglycidyl isocyanurate, and pyromellitic dianhydride; the weight ratio of the chain extender to recycled PETG is (0.5~1.5):(60~100).

[0010] Preferably, the anti-hydrolysis agent is selected from one or more of UN-03, DC-P2, and Stabaxol I; the amount of the anti-hydrolysis agent and the weight ratio of recycled PETG is (0.8~3):(60~100).

[0011] Preferably, the lubricant is selected from one or more of zinc stearate, erucamide, ethylene bis-stearamide, PE wax, EAA wax, and mineral white oil; the weight ratio of the lubricant to the recycled PETG is (1~4):(60~100).

[0012] In a more preferred embodiment, the high-strength heat-resistant and flame-retardant flooring substrate based on recycled PETG is made of the following materials in the following weight ratio: 60-100 parts by weight of recycled PETG, 5-10 parts by weight of compatibilizer, 0.5-1 parts by weight of chain extender, 1-4 parts by weight of lubricant, 0.8-3 parts by weight of anti-hydrolysis agent, 1-2 parts by weight of antioxidant, and 150 parts by weight of modified diatomaceous earth and calcium carbonate [wherein the weight ratio of modified diatomaceous earth to calcium carbonate is (1-3):(2-4)].

[0013] The present invention also provides a method for preparing the aforementioned flooring substrate, comprising the following steps: S1 Material Premix: Place the floor substrate material in a high-speed mixer and mix for 10-30 minutes to obtain a premix. S2 Extrusion Granulation: The premixed material is fed from the hopper into a twin-screw extruder and extruded at 160℃~220℃ to obtain extruded granules; S3 substrate injection molding: Extruded granules are injection molded into floor substrate at 230℃~260℃ using an injection molding machine. The injection pressure is 110MPa~130MPa, the injection speed is 80g / s~120g / s, the injection time is 4s~6s, the holding pressure is 90MPa~110MPa, the holding time is 10s~30s, and the mold temperature controller temperature is 30℃~60℃.

[0014] The present invention further provides a flooring made from the aforementioned flooring substrate.

[0015] Preferably, the upper surface of the floor substrate is covered with a colored film and / or a transparent film, and the bottom of the floor substrate is cold-applied with a sound-absorbing pad.

[0016] The aforementioned term "flooring substrate" refers to the main component of engineered wood flooring, which provides support for the flooring. It is a concept relative to other structural layers of the flooring, such as sound insulation layers and color film layers.

[0017] Beneficial effects

[0018] The flooring substrate of this invention is made primarily of recycled PETG, eliminating the need for other main materials such as PVC, thus improving the utilization rate of recycled resources and the environmental performance of the flooring substrate.

[0019] The flooring substrate and flooring of the present invention, through extensive material formulation research, significantly improve the product's low warpage, low shrinkage, tensile and bending strength, flame retardancy, etc. by using modified diatomaceous earth combined with calcium carbonate, and have the advantages of being lightweight with no arching and low density. Detailed Implementation

[0020] To better demonstrate and illustrate the purpose, technical solution, and features of this invention, the following detailed explanation is provided in conjunction with specific experimental examples and comparative examples. It should be understood that the embodiments are merely illustrative of the invention and are not intended to limit the scope of protection of the invention. After reading the contents of this invention, those skilled in the art can make various simple modifications or alterations to the invention without creative effort, and these equivalent / identical transformations also fall within the scope of protection of this invention.

[0021] All materials used in the following examples are commercially available. Recycled PETG (rPETG) was sourced from Henan Yinjinda New Material Co., Ltd.; the compatibilizer EMA-g-GMA was from SK (Korea), model AX8900; the chain extender styrene-glycidyl methacrylate was from BASF, model ADR 4468; the lubricant PE wax was from Hebei Tianyu Chemical Co., Ltd.; the anti-hydrolysis agent UN-03 was from Shanghai Youen Chemical Co., Ltd.; the antioxidant 1010 was from Tianjin Lianlong New Material Co., Ltd.; and the calcium carbonate was commercially available heavy calcium carbonate (300-500 mesh; for comparability, 400 mesh was used in the experimental and comparative examples). rPETG can also be prepared using existing techniques; relevant literature can be found in CN118082028A (patent literature).

[0022] The following examples use silane coupling agent (KH590) modified diatomaceous earth, prepared by the following method: diatomaceous earth is washed, filtered, and dried with distilled water under ultrasonication. The dried diatomaceous earth and KH590 (in the experimental and comparative examples, the weight ratio of diatomaceous earth to KH590 is 100:1) are added to a high-speed mixer and mechanically stirred for 30 minutes to obtain silane coupling agent modified diatomaceous earth. Obviously, the silane coupling agent in the silane coupling agent modified diatomaceous earth of this invention can also be other silane coupling agents such as KH570, and the silane coupling agent modified diatomaceous earth can also be prepared using other conventional methods of the prior art (e.g., pre-calcining and acid washing of diatomaceous earth to increase porosity). Such preparation methods can be found in patent document CN116006785A.

[0023] Example 1: Preparation of different flooring substrates and flooring This embodiment demonstrates the material formulation and preparation methods of different flooring substrates and flooring, including the material formulation and preparation methods of experimental examples and comparative examples. The material formulation of the flooring substrate for the experimental examples is shown in Table 1, and the material formulation of the flooring substrate for the comparative examples is shown in Table 2.

[0024] Table 1. Ingredients of the flooring substrate for the experimental example (parts by weight)

[0025] Note: (x:y) represents the weight ratio of modified diatomaceous earth to calcium carbonate; the number before the parentheses represents the total weight of modified diatomaceous earth and calcium carbonate.

[0026] Table 2. Comparative Example: Flooring Substrate Ingredient List (parts by weight)

[0027] Note: (x:y) represents the weight ratio of modified diatomaceous earth to calcium carbonate; the number before the parentheses represents the total weight of modified diatomaceous earth and calcium carbonate.

[0028] The preparation methods for the flooring substrate and corresponding flooring samples in the experimental examples are as follows: S1 Material Premix: Take the materials by weight, and put rPETG and other materials (compatibility agent, chain extender, modified diatomaceous earth, calcium carbonate, lubricant, anti-hydrolysis agent, antioxidant, etc.) into a high-speed mixer and mix for 20 minutes to obtain the premix. S2 Extrusion Granulation: The premixed material is fed from the hopper into a twin-screw extruder for extrusion granulation. The temperatures of the screw sections 1-11 are as follows: 165±5℃, 170±5℃, 190±5℃, 200±5℃, 210±5℃, 210±5℃, 210±5℃, 200±5℃, 200±5℃, 180±5℃, to obtain rPETG extruded granules; S3 substrate injection molding: rPETG extruded granules are injection molded into 4mm floor substrate through an injection molding machine. The temperatures of the injection molding machine in sections 1-5 are 230℃, 240℃, 250℃, 250℃ and 255℃ respectively; the injection pressure is 120MPa, the injection speed is 100g / s, the injection time is 5s, the holding pressure is 100MPa, the holding time is 15s, and the mold temperature controller temperature is 50℃.

[0029] S4 flooring preparation: A colored film and a transparent film are applied to the flooring substrate. The colored film is 0.5 mm thick and the transparent film is 1 mm thick. Both the colored film and the transparent film are made of PETG. A sound-absorbing pad is cold-applied to the bottom of the substrate. The sound-absorbing pad is made of IXPE (cross-linked polyethylene foam).

[0030] The preparation methods of the floor substrate and corresponding floor samples in the comparative examples are the same as those in the experimental examples, except that when a certain material is missing in the comparative examples, the material sampling will not involve that material.

[0031] Example 2 Performance Tests of Different Flooring This embodiment demonstrates the performance tests and results of different flooring samples from Example 1. The test methods for each performance index of the flooring samples are as follows: (1) Density test: Tested according to GB / T1033-2008 standard. Take a 50mm×50mm sample, place it on the top of the instrument and weigh it. Then use tweezers to put the sample into the U-shaped frame in the water of the instrument. The sample density is automatically calculated based on the change in water volume.

[0032] (2) Warpage characteristic test: Tested according to GB / T4085-2015 standard. Take a 250mm×250mm sample, place it on a flat table, and use a feeler gauge to test each of the four corners of the sample; for post-baking warpage, place the sample in an 80℃ oven, take it out and cool it after 6 hours, and use a feeler gauge to test the four corners. The maximum value among the four corners is selected from the test results.

[0033] (3) Heat shrinkage characteristic test: Tested according to GB / T 4085-2015 standard. Take a 250mm×250mm sample, measure the length and width of the sample (measure and record the data on all four sides, record the length as L10 and L20, and the width as W10 and W20), place the sample in an 80℃ oven, take it out after 6 hours and place it in the laboratory to stand for 3 hours. After standing, test the length and width of the sample (record the length as L11 and L21, and the width as W11 and W21). Calculate the length: {[(L10+L20) / 2-(L11+L21) / 2] / [(L10+L20) / 2]}×100%; width: {[(W10+W20) / 2-(W11+W21) / 2] / [(W10+W20) / 2]}×100%, and select the maximum value of the test result.

[0034] (4) Tensile strength test: Tested according to GB / T1040.1-2018 standard. Take a standard dumbbell-shaped specimen according to the national standard, fix it in the test area of ​​the tensile tester, set the specimen parameters and machine speed, click start test, and the instrument will automatically generate tensile strength data after the specimen breaks.

[0035] (5) Bending strength test: Test according to GB / T 9341-2008 standard. Take a 4mm×10mm×80mm sample, fix it in the test area of ​​the machine, set the sample parameters and machine speed, click start test, and the instrument will automatically generate bending strength data.

[0036] (6) Notched impact strength test of simply supported beam: Tested according to GB / T1043.1-2008 standard. Take a 4mm×10mm×80mm specimen and make a 1mm notch. Place the specimen in the test area, set the specimen and pendulum parameters, click start test, and the instrument will automatically generate test data.

[0037] (7) Flame retardant performance test: Tested according to GB / T11785-2005 standard. Cut a 1050mm×230mm sample, fix the calibration plate on the combustion test instrument platform for heat flux calibration, and remove the calibration plate after calibration to replace the test plate. Ignite the ignition source torch, and after 120s, the ignition source torch moves forward to ignite the sample. After 720s, the ignition source torch extinguishes and moves back. After the flame is extinguished, the combustion test instrument automatically records the position and calculates the radiation flux.

[0038] (8) Thermal expansion parameter test: Thermal expansion: Cut a 180mm×1220mm sample, measure the length and width of the sample, record the length as L10 and L20, and the width as W10 and W20, place it in the drying room, set the drying room temperature to 1℃, and record the time when the set temperature is reached. After keeping it at the set temperature for 24 hours, measure the length and width, record the length as L11 and L21, and the width as W11 and W21. After the drying room temperature drops to room temperature, place the sample in the laboratory and let it stand for 24 hours, measure the length and width, record the length as L12 and L22, and the width as W12 and W22. Place the sample in the drying room, set the temperature to 38℃, and record the time when the set temperature is reached. After keeping it at the set temperature for 24 hours, measure the length and width, record the length as L13 and L23, and the width as W13 and W23. After the drying room cools to room temperature, place the sample in the laboratory and let it stand for 24 hours, measure the length and width, record the length as L14 and L24, and the width as W14 and W24. The experimental data were calculated. The coefficient of thermal expansion for length is: [(L13+L23) / 2-(L10+L20) / 2] / [(L10+L20) / 2]; the coefficient of thermal expansion for width is: [(W13+W23) / 2-(W10+W20) / 2] / [(W10+W20) / 2]. The maximum value of the test results was selected.

[0039] (9) Illumination test: Cut a 180mm×1220mm sample, place it in the illumination laboratory, set the illumination temperature to 70℃, and irradiate for 3 hours.

[0040] The performance tests and results of the experimental examples and comparative samples are shown in Tables 3 and 4, respectively. Table 3 shows that the flooring prepared from the flooring substrate of this invention (Experimental Examples 1-6) has a tensile strength ≥72.5 MPa, a bending strength ≥21.4 MPa, a notched impact strength of a simply supported beam ≥8.0 MPa, and a flame retardant performance ≥8.0 kW / m². 2 The pre-drying warpage was ≤0.25mm, the pre-drying thermal shrinkage rate was ≤0.08%, the post-drying warpage was ≤0.30mm, the post-drying thermal shrinkage rate was ≤0.11%, the coefficient of thermal expansion was ≤5.4, and no arching was observed during light exposure testing. Although no flame retardant was added, the flame retardant performance of the flooring sample of this invention was still superior to that of the comparative samples; the overall performance indicators were also significantly superior to the flooring prepared from the flooring substrates of Comparative Examples 1 to 5.

[0041] Table 3 Performance parameters of the flooring samples in the experiment

[0042] Table 4 Performance parameters of comparative floor samples

[0043] In summary, the above results indicate that the rPETG flooring substrate provided by this invention is mainly produced by premixing rPETG with other materials, extruding and granulating, and then injection molding. Specifically, this invention blends rPETG with calcium carbonate and modified diatomaceous earth, and adds functional additives, effectively improving the utilization rate of rPETG (using only rPETG, without using non-rPETG). Even though Comparative Example 5 and the experimental example used the same types of materials, a change in the ratio of calcium carbonate and modified diatomaceous earth alone resulted in a significant decrease in warping, expansion, flame retardancy, tensile strength, and impact strength. Therefore, the ratio of calcium carbonate and modified diatomaceous earth is also a key factor in achieving the excellent performance of the flooring substrate and flooring of this invention.

[0044] As can be seen from the above, the flooring substrate and flooring of the present invention have many advantages such as low warpage, low shrinkage, high tensile and bending strength, and good flame retardant properties, and have extremely broad development prospects and huge application potential in the field of environmentally friendly recycled material products. Furthermore, the flooring substrate and flooring of the present invention have low density, which also provides the advantage of lightweight design.

[0045] It should be noted that although the above embodiments have described the technical solution of the present invention in detail, these embodiments are merely illustrative examples and not limiting definitions. Those skilled in the art should understand that any modifications or equivalent substitutions made without departing from the spirit and scope of the technical solution of the present invention should be included within the scope of the claims of the present invention. Therefore, the scope of protection of the present invention should be determined by the content defined in the claims.

Claims

1. A high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG, characterized in that, The flooring substrate is made of recycled PETG as the main material and auxiliary materials, including compatibilizers, chain extenders, lubricants, anti-hydrolysis agents, modified diatomaceous earth, and calcium carbonate; the weight ratio of modified diatomaceous earth to calcium carbonate is (1~3):(2~4); the total amount of modified diatomaceous earth and calcium carbonate to the weight ratio of recycled PETG is 150:(60~100); the modified diatomaceous earth is silane coupling agent modified diatomaceous earth.

2. The high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG according to claim 1, characterized in that, The auxiliary materials also include antioxidants; the amount of antioxidants used is in a weight ratio of (1~2):(60~100) of recycled PETG.

3. The high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG according to claim 2, characterized in that, The antioxidant is selected from one or more of antioxidant 1010, antioxidant 5057, antioxidant 626, and dithiodipropionate.

4. The high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG according to claim 1, characterized in that, The compatibilizer is selected from one or more of EMA-g-GMA, SEBS-g-GMA, POE-g-GMA, ABS-g-MAH, and POE-g-MAH; the amount of the compatibilizer used is in a weight ratio of (5~10):(60~100) of recycled PETG.

5. A high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG according to claim 1, characterized in that, The chain extender is selected from one or more of styrene-glycidyl methacrylate, 2,2-(1,3-phenylene)-bis(2-oxazoline), triglycidyl isocyanurate, and pyromellitic dianhydride; the weight ratio of the chain extender to recycled PETG is (0.5~1.5):(60~100).

6. The high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG according to claim 1, characterized in that, The anti-hydrolysis agent is selected from one or more of UN-03, DC-P2, and Stabaxol I; the amount of the anti-hydrolysis agent and the weight ratio of recycled PETG is (0.8~3):(60~100).

7. A high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG according to claim 1, characterized in that, The lubricant is selected from one or more of zinc stearate, erucamide, ethylene bis-stearamide, PE wax, EAA wax, and mineral white oil; the weight ratio of the lubricant to recycled PETG is (1~4):(60~100).

8. A method for preparing a high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG as described in any one of claims 1 to 7, comprising the following steps: S1 Material Premix: Place the floor substrate material in a high-speed mixer and mix for 10-30 minutes to obtain a premix. S2 Extrusion Granulation: The premixed material is fed into a twin-screw extruder and extruded at 160℃~220℃ to obtain extruded granules; S3 substrate injection molding: Extruded granules are injection molded into floor substrate at 230℃~260℃ using an injection molding machine. The injection pressure is 110MPa~130MPa, the injection speed is 80g / s~120g / s, the injection time is 4s~6s, the holding pressure is 90MPa~110MPa, the holding time is 10s~30s, and the mold temperature controller temperature is 30℃~60℃.

9. A flooring made from a high-strength, heat-resistant, and flame-retardant flooring substrate based on recycled PETG as described in any one of claims 1 to 7, or a flooring substrate prepared by the preparation method of claim 8, characterized in that, The upper surface of the floor substrate is covered with a colored film and / or a transparent film, and a sound-absorbing pad is cold-applied to the bottom of the floor substrate.

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