Stone-plastic composite floor and preparation method thereof

Abstract

The invention belongs to the field of composite board manufacturing, and particularly relates to a stone-plastic composite floor and a preparation method thereof. The method comprises the steps that (1) nano alloy powder is placed in pretreatment liquid to be subjected to thermal ultrasonic modification treatment, and modified nano alloy powder is obtained; 2) crushing calcareous dolomite into micro powder, and then premixing the micro powder with an oily plasticizer to prepare compound slurry; 3) mixing PVC resin, a lubricant and the modified nano alloy powder for low-temperature dry mixing, then adding the compound slurry and a stabilizer for heating premixing, and then adding a cross-linking agent for high-temperature mixing to obtain a mixture; and (4) adding a foaming agent into the mixture, performing final mixing, performing tabletting forming, and performing gradient hot pressing treatment to obtain the stone-plastic composite floor. According to the calcium-based stone powder stone-plastic composite floor, multiple synergistic effects are stimulated through the filler, a multi-network structure is constructed, the dispersion uniformity of the filler is improved, the mechanical performance, sound insulation performance and heat insulation performance of the calcium-based stone powder stone-plastic composite floor are comprehensively optimized and improved, and performance jump of a low-cost product is achieved.

Description

Technical Field

[0001] The invention belongs to the field of composite board manufacturing, and in particular relates to a stone-plastic composite floor and a preparation method thereof. Background Art

[0002] Stone Plastic Composite (SPC) is a new type of environmentally friendly building material with stone powder as the main filler and thermoplastic polymer materials such as PVC as the matrix. It combines the stability of stone and the processability of plastic, and can simulate the texture and texture of stone flooring to a certain extent. Therefore, it is widely used in floor decoration in residential, commercial spaces and public places.

[0003] According to the difference in the composition of stone powder fillers, the current stone-plastic composite flooring is mainly divided into silicon-based stone powder stone-plastic composite flooring mainly composed of silicate minerals, and calcium-based stone powder stone-plastic composite flooring mainly composed of calcium carbonate minerals. These two types of stone-plastic composite flooring show significant differences in performance and economy.

[0004] Silica-based stone powder plastic composite flooring offers significant advantages in many areas, such as wear resistance, thermal insulation, and various strength indicators. Furthermore, the interface between calcium carbonate and PVC is clear, the bonding is relatively limited, and it is prone to shedding. Therefore, silica-based stone powder plastic composite flooring far outperforms calcium-based stone powder plastic composite flooring in most performance aspects. However, calcium carbonate minerals are widely available, and their cost is often less than half that of silicate minerals, or even lower. Furthermore, they are easier to process and require fewer additives, resulting in production costs far lower than silica-based stone powder plastic composite flooring, offering a significant cost-performance advantage. With these significant cost and environmental advantages, calcium-based stone powder plastic composite flooring remains a mainstream product in the market.

[0005] However, its performance drawbacks are not to be ignored. Consequently, in recent years, research on calcium-based stone powder-plastic composite flooring has been extensive. Besides improving the matrix composition, most research focuses on metal / metal oxide reinforcement. Three main research directions exist: metal oxide coating reinforcement, such as applying a nanoparticle coating of aluminum oxide or titanium oxide to the wear-resistant layer to improve surface hardness and scratch resistance. However, such coatings are prone to detachment due to insufficient interfacial bonding. Furthermore, the introduction of some precious metals and / or precious metal oxides can weaken or even completely eliminate their cost advantages. Second, metal fiber reinforcement involves incorporating stainless steel or aluminum fibers into the base layer to enhance impact resistance through mechanical interlocking. However, metal fibers have poor compatibility with the PVC matrix and can easily induce interfacial stress concentration, leading to delamination. Third, metal powder fillers are added to stone powder fillers, such as blending copper or iron powder with stone powder to leverage the metal's thermal conductivity to improve the floor's heat dissipation. However, these also present similar challenges as metal fibers, prone to interfacial stress concentration, leading to delamination.

[0006] Clearly, the main challenges facing current metal / metal oxide reinforced SPC composite flooring are dispersibility and bonding issues. Furthermore, metal / metal oxides often increase the brittleness of SPC composite flooring. Furthermore, due to the mismatch between the thermal expansion coefficients of some metal / metal oxides and the substrate, cracking is more likely to occur in areas with large year-round temperature differences or short-term temperature fluctuations. Clearly, metal / metal oxide reinforced calcium-based stone powder SPC composite flooring still faces numerous challenges that need to be addressed. Summary of the Invention

[0007] In order to solve the many performance defects of existing calcium-based stone powder stone plastic composite flooring, and the current research on the strengthening of calcium-based stone powder stone plastic composite flooring has also fallen into some bottlenecks and misunderstandings, resulting in weakened cost advantages or performance imbalances, and even the generation of new performance defects and other problems, the present invention provides a calcium-based stone powder stone plastic composite flooring, and a preparation method of the stone plastic composite flooring.

[0008] The main objectives of the present invention are:

[0009] 1. Through special treatment and addition methods, the strengthening effect of metal-based materials on stone-plastic composite flooring is changed;

[0010] 2. Comprehensively improve the mechanical properties of stone plastic composite flooring through the coordinated cooperation of multiple components;

[0011] 3. Construct a specific microstructure system to weaken the negative effects of metal-based materials on stone-plastic composite flooring.

[0012] To achieve the above objectives, the present invention adopts the following technical solutions.

[0013] A preparation method of stone-plastic composite flooring,

[0014] The method comprises:

[0015] 1) placing the nano alloy powder in a pretreatment solution for thermal ultrasonic modification to obtain modified nano alloy powder;

[0016] 2) crushing the calcareous dolomite into fine powder, and then premixing the fine powder with an oily plasticizer to prepare a compound slurry;

[0017] 3) mixing the PVC resin, lubricant and modified nano alloy powder and performing dry mixing at low temperature, then adding the compound slurry and stabilizer and premixing at elevated temperature, and then adding the cross-linking agent and performing high temperature mixing to obtain a mixture;

[0018] 4) Adding a foaming agent to the mixture for final mixing and then pressing the mixture into sheets to obtain a pre-sheet, and subjecting the pre-sheet to a gradient hot pressing treatment to obtain a stone-plastic composite floor.

[0019] As a preference,

[0020] Step 1) The nano alloy powder is CSZ532 alloy powder, and its mesh number is ≥300 mesh;

[0021] Step 1) The pretreatment liquid is a KH550-ethanol solution with a KH550 concentration of 1 to 3 wt%;

[0022] In step 1), the thermal ultrasonic modification treatment is performed at 55-65° C. for 50-70 minutes, and the modified nano alloy powder is obtained after drying.

[0023] As a preference,

[0024] In step 2), the mass ratio of CaO to MgO in the calcareous dolomite after conversion is (2-2.5):1, and the calcium and / or magnesium components in the calcareous dolomite account for 95wt% or more of its total mass.

[0025] As a preference,

[0026] Step 2) the micro powder mesh size is 200-300 mesh;

[0027] In step 2), the oily plasticizer is dioctyl phthalate, and the premixing process is to disperse the micropowder in the oily plasticizer and perform ultrasonic-assisted dispersion to prepare a dispersion with a solid content of 60-70 wt %, which is the compound slurry.

[0028] As a preference,

[0029] Step 3) The lubricant is a microcrystalline wax with a molecular weight of 400 to 600;

[0030] Step 3) The mass ratio of the PVC resin, lubricant and modified nano alloy powder is 100: (1.0-1.5): (1.5-2.5);

[0031] The low-temperature dry mixing process in step 3) is to stir and mix at 80-90° C. for 5-10 minutes.

[0032] As a preference,

[0033] Step 3) The amount of the compounded slurry is 15-20 g / 100 g PVC resin;

[0034] Step 3) The stabilizer is a mixture of a calcium zinc stabilizer and an organotin stabilizer. Both stabilizers used in the present invention are purchased from Bangtai Chemical, and the calcium zinc stabilizer is a solid calcium zinc stabilizer. Compared with liquid calcium zinc stabilizers, solid calcium zinc stabilizers are less likely to produce segregation, precipitation and other problems. Common PVC processing usually uses liquid calcium zinc stabilizers (especially under the dosage conditions of the present invention). However, the present invention can effectively achieve the dispersion of solid calcium zinc stabilizers through multi-component and process synergy, thereby effectively controlling costs and more effectively stabilizing the matrix. The amount of calcium zinc stabilizer is 1.8-2.2g / 100g PVC resin, and the amount of organotin stabilizer is 0.3-0.7g / 100g PVC resin;

[0035] In step 3), the heating premixing is performed by stirring the premixing at 160-170° C. for 10-12 minutes.

[0036] As a preference,

[0037] Step 3) The cross-linking agent is dicumyl peroxide, and the amount thereof is 1.5 to 2.5 g / 100 g PVC resin;

[0038] The high temperature mixing in step 3) is performed at 180-190° C. for 8-10 minutes.

[0039] As a preference,

[0040] Step 4) The foaming agent is AC foaming agent, and its usage is 0.5-1.0g / 100g PVC resin;

[0041] Step 4) The temperature of the final mixing process is controlled at 190-195° C., the mixing time is 6-10 minutes, and then a pressure of 20-35 MPa is applied at 40-60° C. and maintained for 2-5 minutes to form a pre-sheet.

[0042] As a preference,

[0043] Step 4) The gradient hot pressing treatment is performed on both sides of the pre-sheet, and includes a pressurization stage, a pressure release stage, and a pressure holding stage in sequence;

[0044] During the pressurization stage, the hot pressing temperature is controlled to be 180-185°C, the hot pressing pressure is controlled to be 10-15 MPa, and the pressing time is controlled to be 60-120 seconds;

[0045] During the pressure release stage, the temperature is controlled to drop to 150-155°C and the pressure is directly released, and the pressure release stage is maintained for 30-60 seconds;

[0046] During the pressure holding stage, the temperature is controlled to be reduced to 40-60° C., the pressing pressure is 10-15 MPa, and the pressing time is 3-5 minutes. After completion, the pressing is released and the stone-plastic composite floor is obtained after cooling to room temperature.

[0047] A stone-plastic composite floor.

[0048] The core of the technical solution of the present invention is to use a relatively special alloy powder for filling while initiating multiple chain reactions to achieve the dispersion of the alloy powder and the effective coordination between the various components, and to construct a specific microporous structure.

[0049] Specifically, the present invention uses a special copper alloy, CSZ532, which is purchased from Anhui Dequan New Materials. 0.5 Sn 0.3 Zn 0.2 The ternary alloy (i.e., the atomic ratio of Cu:Sn:Zn is 5:3:2) has a lower melting point than other types of copper alloys. Furthermore, its three components not only work synergistically but also possess relatively high stability. The alloying elements Sn and Zn prevent the Cu in the alloy from excessive oxidation during the processing of the present invention.

[0050] Based on the CSZ532 alloy, the present invention uses a small amount of extremely low melting point segregated alloy phase in the alloy powder to form local melting, and forms thermal activation points through local melting. For example, the melting point of some Sn-Zn eutectic alloy phases is lower than 200°C. During the processing of the technical solution of the present invention, they can serve as dispersed thermal activation points, accelerate the movement of PVC chain segments during high-temperature mixing and final mixing, and stimulate cross-linking reactions. Prior to this, during the low-temperature dry mixing and temperature-raising pre-mixing processes, the main component of the CSZ532 ternary alloy, Cu, as a transition metal, has a unique d orbital electronic structure that can effectively regulate electron density and promote electron transfer. This electronic structure enables it to interact with the C-Cl bond in PVC, reduce the dissociation energy of the C-Cl bond, and thus promote its homolytic cleavage to generate Cl· free radicals. On this basis, Cu and Zn both have the ability to react with Cl -The coordination ability to form coordination bonds enables multi-point coordination connection, that is, the initial synergistic initiation and construction of a dynamic physical cross-linking network is formed through its own components, and the free radicals recombine to form a CC or COC covalent cross-linking network. This multiple network structure lays the foundation for the effective binding, dispersion and subsequent fixation of CSZ, while limiting the slippage of PVC chain segments during this stage.

[0051] In addition, in addition to the good self-synergy of CSZ532 alloy powder in the PVC system and its ability to initially build a dynamic physical cross-linking network, it also has a good promoting effect on the combination of calcium-based stone powder filler and PVC. This is because under the action of CSZ532 alloy powder, the calcium-based stone powder can form more ion-dipole interactions with the chloride ions formed by the PVC chain, and the copper and zinc in the dynamic physical cross-linking network can form coordination with the hydroxyl groups (some mineral calcium carbonate surfaces are rich in hydroxyl groups) or carbonate groups on the surface of calcium carbonate, further indirectly enhancing the combination of calcium-based stone powder and PVC. Compared with the traditional calcium-based stone powder stone-plastic composite flooring that directly uses calcium carbonate, the present invention uses high-calcium dolomite ore (i.e., calcareous dolomite) with lower cost and easier to obtain. This is not only to reduce costs, but more importantly, during the research and development process, the present invention also found that directly using calcium carbonate micropowder as a filler may cause filler agglomeration, which in turn leads to poor preparation effect. Calcium dolomite contains relatively rich magnesium oxide. Even if its surface has more oxygen vacancies and alkaline sites, the zinc ions released by CSZ532 can form a Zn-O-Mg continuum with it, so that the effective dispersion of CSZ532 alloy powder can also effectively drive the dispersion of calcareous dolomite micropowder, inhibiting agglomeration while effectively controlling the dispersibility of the two fillers without the need for additional operations to promote the dispersion of stone powder filler, greatly simplifying the process while optimizing the preparation effect, and also producing further dynamic coordination, which is significantly helpful in improving the comprehensive mechanical properties of stone-plastic composite flooring.

[0052] In addition, due to the addition and use of multiple fillers, in order to further ensure the dispersibility of the fillers, the present invention also adds a small amount of microcrystalline wax as a lubricant, which can cooperate with the stabilizer to produce external lubrication synergy, effectively reduce the viscosity of the material during the refining process, and promote the dispersion of the fillers. The better the uniformity of the material dispersion, the more complete and uniform the multiple networks constructed are, which can also effectively and significantly reduce the brittleness of the stone-plastic composite floor and make it have better resistance to temperature changes.

[0053] After the three-stage refining in step 3), the present invention further adds a foaming agent for final mixing. This is also to ensure that CSZ532 and calcareous dolomite can first be effectively evenly dispersed and relatively fixed, and after local melting heat activation, the PVC chain segment movement degree is higher. At this time, the foaming agent can foam to form more fine and tiny bubbles, and the evenly dispersed CSZ532 in this foaming process can act as a nucleating agent. In particular, after local melting heat activation, the surface roughness of the CSZ532 alloy powder increases, which can effectively serve as a nucleation point to promote bubble nucleation and drive the uniform dispersion of bubbles. The multiple network structure limits the merging and escape of bubbles. Under the combined effect, the stone-plastic composite floor forms rich and evenly dispersed bubble holes. However, these bubble holes will inevitably appear on the surface of the stone-plastic composite floor. Therefore, the present invention further performs a gradient hot pressing treatment.

[0054] During the gradient hot pressing process, the high temperature hot pressing in the first stage (i.e. the pressurization stage) can cause slight melting damage to the surface. After a period of time, the temperature is immediately lowered and the pressure is released (i.e. the pressure release stage) to allow the surface bubbles to escape and at the same time re-stimulate the local melting heat activation, so that the surface is closed to form a smooth and hard surface shell. In this way, the front and back surfaces of the stone plastic composite floor can be effectively closed and fixed while increasing the surface hardness, ensuring that the stone plastic composite floor has good thermal insulation and sound insulation properties. The final pressure holding stage is to further ensure the flatness of the stone plastic composite floor surface and make the final optimization of the product surface.

[0055] In summary, the present invention actually uses a special Cu-Sn-Zn ternary alloy as the core of multi-faceted synergy, constructing a multiple microscopic network structure (including a chemical cross-linking network and a dynamic physical cross-linking network), improving the bonding strength between the special stone powder filler and the PVC matrix and promoting filler dispersion, while also serving as a nucleation point to promote bubble nucleation, comprehensively improving all aspects of the performance of the stone-plastic composite floor. In contrast, during the research and development process, the present invention also used a mixture of copper powder, zinc powder, and tin powder, rather than a ternary alloy. First, its self-synergistic ability was suppressed, and the actual use effect was not good. In particular, in terms of promoting dispersion and bubble nucleation, the performance differences were extremely large. Therefore, the use of a ternary alloy is relatively the most critical.

[0056] In addition to the above-mentioned multi-faceted synergy, the present invention also uses a compound of calcium zinc stabilizer and organotin stabilizer as the stabilizer. Due to the particularity of the system of the present invention, the preparation process requires comprehensive optimization of thermal stability, filler dispersibility and processability. The calcium zinc stabilizer and organotin stabilizer can significantly improve the aforementioned various performances through thermal stability complementarity, filler dispersion optimization and processing performance synergy, making the product quality more stable and the processing process more stable.

[0057] The beneficial effects of the present invention are:

[0058] The present invention stimulates multiple synergistic effects through fillers, constructs multiple network structures and improves the dispersion uniformity of fillers, comprehensively optimizes and improves the mechanical properties, sound insulation and heat insulation properties of the calcium-based stone powder stone plastic composite floor, and achieves a performance leap of low-cost products. DETAILED DESCRIPTION

[0059] The present invention is further described in detail below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only a portion of the embodiments of the present invention, rather than all of the embodiments. Therefore, all other embodiments derived by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0060] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0061] Unless otherwise specified, the calcareous dolomite used in the embodiments of the present invention has a mass ratio of CaO to MgO of 2.2:1 after conversion, and the total content of calcium and magnesium components in the calcareous dolomite is ≥95 wt%.

[0062] Example 1

[0063] A method for preparing a stone-plastic composite floor, comprising:

[0064] 1) placing 300-mesh CSZ532 alloy powder in a 2 wt% KH550-ethanol solution and subjecting it to a thermosonic modification treatment at 60° C. for 60 min, followed by drying to obtain modified nano-alloy powder;

[0065] 2) crushing calcareous dolomite into 300-mesh fine powder, and then premixing the powder with dioctyl phthalate to prepare a dispersion having a solid content of 65 wt %, i.e., a composite slurry;

[0066] 3) PVC resin, microcrystalline wax with a molecular weight of 500, and modified nano-alloy powder were mixed in a mass ratio of 100:1.25:2 and dry-mixed at 85° C. for 8 min, followed by adding the compound slurry in an amount of 15 g / 100 g PVC resin, adding a calcium zinc stabilizer in an amount of 2.0 g / 100 g PVC resin, and adding an organic tin stabilizer in an amount of 0.5 g / 100 g PVC resin, and pre-mixing at 165° C. for 10 min, and then adding dicumyl peroxide in an amount of 2.0 g / 100 g PVC resin and mixing at 185° C. for 8 min to obtain a mixture;

[0067] 4) adding an AC foaming agent to the mixture at a ratio of 0.8 g / 100 g of PVC resin, performing final mixing at 195 ° C for 3 minutes, and then applying a pressure of 30 MPa at 55 ° C for 5 minutes to obtain a pre-plate. The front and back sides of the pre-plate are processed in sequence, including a pressurization stage, a pressure release stage, and a pressure holding stage. The pressurization stage controls the hot pressing temperature to 185 ° C, the hot pressing pressure is 12 MPa, and the pressing time is 120 seconds. In the pressure release stage, the temperature is quickly cooled to 155 ° C and the pressing is directly released. The pressure release stage is maintained for 45 seconds. The temperature is controlled to 50 ° C in the pressure holding stage, the pressing pressure is 12 MPa, and the pressing time is 5 minutes. After completion, the pressing is released and cooled to room temperature to obtain a stone plastic composite floor.

[0068] The performance of the stone-plastic composite floor prepared in this example was characterized, including specific gravity characterization, surface porosity (front and back sides only), surface roughness Ra (front and back sides only), Taber abrasion test, surface hardness characterization (front and back sides only), impact strength characterization, sound insulation performance characterization, thermal insulation performance characterization and crack resistance characterization.

[0069] The Taber abrasion test load is 1.0 kg, with the unit being mg / 1000 revolutions. Sound insulation performance is characterized by impact sound pressure degradation (denoted as sound insulation A, specifically referring to the international standard ISO 717-2) and airborne sound insulation (denoted as sound insulation B, specifically referring to the international standard ISO 717-1). Thermal insulation performance is mainly characterized by the thermal conductivity of the front and back sides of the stone plastic composite floor (unit: W / (m·K)). Cracking resistance is characterized by a -10 / 40°C cyclic insulation cycle, with each cycle lasting 12 hours, including a low-temperature stage and a high-temperature stage. In the low-temperature stage, the sample is cooled to -10°C and maintained for 6 hours before entering the high-temperature stage, where the temperature is raised to 40°C within 15 minutes and maintained at the high-temperature stage for 6 hours. The sample is then cooled to -10°C within the same 15 minutes. After each high-temperature stage, the sample is observed as the end of the cycle to see if it cracks, and the number of cycles in which cracking occurs is recorded. A maximum of 60 cycles are performed, and no cracking after 60 cycles is marked as excellent.

[0070] The specific characterization results are shown in the following table.

[0071] <![CDATA[Specific gravity (g / cm 3 )]]> Surface opening rate (%) Surface roughness Ra Taber abrasion Surface Shore hardness D 1.69 3.7 1.9μm 7.2 86 <![CDATA[Impact strength (kJ / m 2 )]]> Sound insulation A(dB) Sound insulation B (dB) Thermal conductivity Cracking resistance 11.3 21 37 0.049 excellent

[0072] The above characterization results clearly demonstrate that the stone-plastic composite flooring of the present invention exhibits a low specific gravity and low surface porosity, with a high actual internal porosity, resulting in excellent sound and heat insulation. In terms of sound insulation A, sound insulation B, and thermal conductivity, the calcium carbonate stone-plastic composite flooring prepared by the present invention significantly improves the shortcomings of traditional calcium-based stone powder stone-plastic composite flooring, which has almost no sound and heat insulation capabilities. Furthermore, the surface porosity and roughness indicate that the surface has been effectively treated, resulting in an overall smooth and flat surface. It also exhibits high rigidity and strong wear resistance. On the other hand, generally speaking, stone-plastic composite floors reinforced with metal fillers or silicon-based fillers generally have the problem of mismatched thermal expansion coefficients of the components and poor crack resistance. The unique CSZ-Ca / Mg-bubble core system constructed by the present invention not only has a large number of gaps inside to form sound insulation and heat insulation effects, but also has internal expansion margin space, which greatly reduces freeze-thaw cycle cracking caused by differences in thermal expansion coefficients. Therefore, it has very excellent use effects in both the north and the south, breaking through the original limitation of "calcium-based stone-plastic composite floors are suitable for the north and silicon-based stone-plastic composite floors are suitable for the south".

[0073] Example 2

[0074] A method for preparing a stone-plastic composite floor, comprising:

[0075] 1) placing 300-mesh CSZ532 alloy powder in a 2 wt% KH550-ethanol solution and subjecting it to a thermosonic modification treatment at 60° C. for 60 min, followed by drying to obtain modified nano-alloy powder;

[0076] 2) crushing calcareous dolomite into 300-mesh fine powder, and then premixing the powder with dioctyl phthalate to prepare a dispersion having a solid content of 65 wt %, i.e., a composite slurry;

[0077] 3) PVC resin, microcrystalline wax with a molecular weight of 500, and modified nano-alloy powder were mixed in a mass ratio of 100:1.25:2.5 and dry-mixed at 85° C. for 8 min, followed by adding the compound slurry in an amount of 20 g / 100 g PVC resin, adding a calcium zinc stabilizer in an amount of 2.0 g / 100 g PVC resin, and adding an organic tin stabilizer in an amount of 0.5 g / 100 g PVC resin, and pre-mixing at 165° C. for 10 min, and then adding dicumyl peroxide in an amount of 2.0 g / 100 g PVC resin and mixing at 185° C. for 8 min to obtain a mixture;

[0078] 4) adding an AC foaming agent to the mixture at a ratio of 0.8 g / 100 g of PVC resin, performing final mixing at 195 ° C for 3 minutes, and then applying a pressure of 30 MPa at 55 ° C for 5 minutes to obtain a pre-plate. The front and back sides of the pre-plate are processed in sequence, including a pressurization stage, a pressure release stage, and a pressure holding stage. The pressurization stage controls the hot pressing temperature to 185 ° C, the hot pressing pressure is 12 MPa, and the pressing time is 120 seconds. In the pressure release stage, the temperature is quickly cooled to 155 ° C and the pressing is directly released. The pressure release stage is maintained for 45 seconds. The temperature is controlled to 50 ° C in the pressure holding stage, the pressing pressure is 12 MPa, and the pressing time is 5 minutes. After completion, the pressing is released and cooled to room temperature to obtain a stone plastic composite floor.

[0079] The stone-plastic composite flooring produced in this example was characterized for specific gravity, surface porosity (front and back sides only), surface roughness Ra (front and back sides only), Taber abrasion test, surface hardness (front and back sides only), impact strength, sound insulation, thermal insulation, and crack resistance. The characterization methods were the same as in Example 1.

[0080] The specific characterization results are shown in the following table.

[0081] <![CDATA[Specific gravity (g / cm 3 )]]> Surface opening rate (%) Surface roughness Ra Taber abrasion Surface Shore hardness D 1.73 3.3 2.0μm 6.7 87 <![CDATA[Impact strength (kJ / m 2 )]]> Sound insulation A(dB) Sound insulation B (dB) Thermal conductivity Cracking resistance 11.0 22 37 0.051 excellent

[0082] The above characterization results clearly show that increasing the relative filler dosage in this example resulted in a significant increase in specific gravity and some changes in surface properties, with a decrease in open porosity, a slight increase in roughness, and a decrease in wear. The decrease in wear, in particular, warrants special attention. Firstly, the magnitude of the decrease is significant, and secondly, Taber wear loss in stone-plastic composite flooring is typically caused by poor filler bonding, leading to detachment. However, in the technical solution of the present invention, increasing the relative filler dosage actually increases wear, indicating that the bonding strength between the filler and the substrate is very good, and the filler on the surface is not easily detached, effectively achieving surface reinforcement for the floor.

[0083] Example 3

[0084] A method for preparing a stone-plastic composite floor, comprising:

[0085] 1) placing 300-mesh CSZ532 alloy powder in a 2 wt% KH550-ethanol solution and subjecting it to a thermosonic modification treatment at 60° C. for 60 min, followed by drying to obtain modified nano-alloy powder;

[0086] 2) crushing calcareous dolomite into 300-mesh fine powder, and then premixing the powder with dioctyl phthalate to prepare a dispersion having a solid content of 65 wt %, i.e., a composite slurry;

[0087] 3) PVC resin, microcrystalline wax with a molecular weight of 500, and modified nano-alloy powder were mixed in a mass ratio of 100:1.25:1.5 and dry-mixed at 85° C. for 8 min, followed by adding the compound slurry in an amount of 20 g / 100 g PVC resin, adding a calcium zinc stabilizer in an amount of 2.0 g / 100 g PVC resin, and adding an organic tin stabilizer in an amount of 0.5 g / 100 g PVC resin, and pre-mixing at 165° C. for 10 min, and then adding dicumyl peroxide in an amount of 2.0 g / 100 g PVC resin and mixing at 185° C. for 8 min to obtain a mixture;

[0088] 4) adding an AC foaming agent to the mixture at a ratio of 0.8 g / 100 g of PVC resin, performing final mixing at 195 ° C for 3 minutes, and then applying a pressure of 30 MPa at 55 ° C for 5 minutes to obtain a pre-plate. The front and back sides of the pre-plate are processed in sequence, including a pressurization stage, a pressure release stage, and a pressure holding stage. The pressurization stage controls the hot pressing temperature to 185 ° C, the hot pressing pressure is 12 MPa, and the pressing time is 120 seconds. In the pressure release stage, the temperature is quickly cooled to 155 ° C and the pressing is directly released. The pressure release stage is maintained for 45 seconds. The temperature is controlled to 50 ° C in the pressure holding stage, the pressing pressure is 12 MPa, and the pressing time is 5 minutes. After completion, the pressing is released and cooled to room temperature to obtain a stone plastic composite floor.

[0089] The stone-plastic composite flooring produced in this example was characterized for specific gravity, surface porosity (front and back sides only), surface roughness Ra (front and back sides only), Taber abrasion test, surface hardness (front and back sides only), impact strength, sound insulation, thermal insulation, and crack resistance. The characterization methods were the same as in Example 1.

[0090] The specific characterization results are shown in the following table.

[0091] <![CDATA[Specific gravity (g / cm 3 )]]> Surface opening rate (%) Surface roughness Ra Taber abrasion Surface Shore hardness D 1.70 4.9 2.3μm 9.5 83 <![CDATA[Impact strength (kJ / m 2 )]]> Sound insulation A(dB) Sound insulation B (dB) Thermal conductivity Cracking resistance 10.7 17 35 0.058 excellent

[0092] It can be clearly seen from the above characterization results that this example reduced the amount of CSZ532 alloy and increased the relative amount of calcareous dolomite, which led to an imbalance in the internal structure of the product. In terms of surface porosity, the relatively excessive amount of calcareous dolomite connected to the CSZ532 alloy may lead to a reduction in the nucleation points for bubble nucleation and fixation, resulting in increased bubble fusion and overflow. The more direct manifestation is the increase in surface porosity, and the relatively excessive amount of calcareous dolomite also makes it impossible to form highly uniform diffusion and bonding with the CSZ532 alloy powder. The surface roughness Ra and Taber wear are increased, the brittleness is enhanced, and the overall sound insulation and heat insulation effects are weakened. However, it is relatively stable that it can still effectively possess good crack resistance, thereby ensuring its stability in use, and it still has a relatively good overall use effect.

[0093] Comparative Example 1

[0094] Three commercially available calcium-based stone powder plastic composite floors and two silica-based stone powder plastic composite floors were sampled and subjected to the same performance characterization as in Example 1. The characterization results are shown in the following table.

[0095]

[0096] The table above clearly shows that commercially available calcium-based stone powder SPC composite flooring and silica-based stone powder SPC composite flooring exhibit distinct performance trends. For example, calcium-based stone powder SPC composite flooring generally has a higher Shore hardness, while silica-based stone powder SPC composite flooring has higher impact strength and offers superior sound and heat insulation compared to conventional calcium-based stone powder SPC composite flooring. In terms of crack resistance, calcium-based stone powder SPC composite flooring has a slight advantage. However, characterization results for commercially available calcium-based stone powder (calcium carbonate) metal-reinforced (alumina-doped) SPC composite flooring C also show that the introduction of metal reinforcement improves its hardness, wear resistance, impact strength, and thermal insulation, but significantly decreases its crack resistance, demonstrating the significant drawbacks of existing metal-reinforced solutions for calcium-based stone powder SPC composite flooring. In comparison, the special filler of the present invention induces microstructure and reinforcement, which reduces the specific gravity of the calcium-based stone powder stone plastic composite floor of the present invention, significantly optimizes and improves the wear resistance and impact strength, and the thermal insulation and sound insulation performance can reach a level close to that of the silicon-based stone powder stone plastic composite floor. The crack resistance is far superior to all existing stone plastic composite floors. It can be seen that the calcium-based stone powder stone plastic composite floor of the present invention can achieve almost all-round improvement in the performance of stone plastic composite floor.

[0097] Comparative Example 2

[0098] A method for preparing a stone-plastic composite floor, comprising:

[0099] 1) 300-mesh copper powder, tin powder, and zinc powder were placed in a 2 wt % KH550-ethanol solution and subjected to a thermosonic modification treatment at 60° C. for 60 min, followed by drying to obtain modified copper powder, modified tin powder, and modified zinc powder, respectively;

[0100] 2) crushing calcareous dolomite into 300-mesh fine powder, and then premixing the powder with dioctyl phthalate to prepare a dispersion having a solid content of 65 wt %, i.e., a composite slurry;

[0101] 3) PVC resin, microcrystalline wax with a molecular weight of 500 and metal powder (modified copper powder, modified tin powder and modified zinc powder are mixed in a mass ratio of 2.43:2.72:1, which is approximately equivalent to an atomic ratio of 5:3:2) are mixed in a mass ratio of 100:1.25:2 and dry-mixed at 85°C for 8 minutes, followed by adding the compound slurry in an amount of 15g / 100g PVC resin, adding a calcium zinc stabilizer in an amount of 2.0g / 100g PVC resin, and adding an organic tin stabilizer in an amount of 0.5g / 100g PVC resin, heating to 165°C for premixing for 10 minutes, and then adding diisopropylbenzene peroxide in an amount of 2.0g / 100g PVC resin and mixing at 185°C for 8 minutes to obtain a mixture;

[0102] 4) adding an AC foaming agent to the mixture at a ratio of 0.8 g / 100 g of PVC resin, performing final mixing at 195 ° C for 3 minutes, and then applying a pressure of 30 MPa at 55 ° C for 5 minutes to obtain a pre-plate. The front and back sides of the pre-plate are processed in sequence, including a pressurization stage, a pressure release stage, and a pressure holding stage. The pressurization stage controls the hot pressing temperature to 185 ° C, the hot pressing pressure is 12 MPa, and the pressing time is 120 seconds. In the pressure release stage, the temperature is quickly cooled to 155 ° C and the pressing is directly released. The pressure release stage is maintained for 45 seconds. The temperature is controlled to 50 ° C in the pressure holding stage, the pressing pressure is 12 MPa, and the pressing time is 5 minutes. After completion, the pressing is released and cooled to room temperature to obtain a stone plastic composite floor.

[0103] The stone-plastic composite flooring produced in this example was characterized for specific gravity, surface porosity (front and back sides only), surface roughness Ra (front and back sides only), Taber abrasion test, surface hardness (front and back sides only), impact strength, sound insulation, thermal insulation, and crack resistance. The characterization methods were the same as in Example 1.

[0104] The specific characterization results are shown in the following table.

[0105] <![CDATA[Specific gravity (g / cm 3 )]]> Surface opening rate (%) Surface roughness Ra Taber abrasion Surface Shore hardness D 1.82 1.8 3.3μm 23.6 83 <![CDATA[Impact strength (kJ / m 2 )]]> Sound insulation A(dB) Sound insulation B (dB) Thermal conductivity Cracking resistance 7.1 8 19 0.26 49

[0106] It can be clearly seen from the above characterization results that after replacing the original CSZ532 alloy powder with equivalent amounts of copper powder, tin powder and zinc powder, the self-synergistic effect is significantly weakened, resulting in the inability to form a CSZ532 core, but instead each disperses to form a Cu core and a Zn core. As an important alloying element, tin powder can hardly constitute an effective strengthening effect when used alone, and can only play a filling role, and it itself is not suitable for filling strengthening. In terms of performance, due to the splitting of the core nodes, Cu core and Zn core are formed respectively, which cannot be effectively dispersed and cannot be effectively coordinated, resulting in increased surface roughness of the sample prepared in this example, a cliff-like drop in wear resistance, and the impact strength and sound insulation performance cannot be effectively enhanced and improved, which is closer to the conventional calcium carbonate system calcium-based stone powder stone plastic composite floor, and even produces a reverse increase. This is mainly because the addition of metal fillers themselves will increase the thermal conductivity of the board, especially when it is impossible to effectively construct rich and uniform internal pores. The metal fillers are more likely to form heat transfer chains, and the thermal insulation effect is further reduced compared with the conventional calcium carbonate system calcium-based stone powder stone plastic composite floor. In addition, due to the limited dispersion uniformity of each metal powder filler, it is impossible to form a multiple micro-network structure. The difference in thermal expansion coefficient between the filler and the substrate causes its anti-cracking ability to decrease significantly.

[0107] Comparative Example 3

[0108] A method for preparing a stone-plastic composite floor, comprising:

[0109] 1) placing 300-mesh CSZ532 alloy powder in a 2 wt% KH550-ethanol solution and subjecting it to a thermosonic modification treatment at 60° C. for 60 min, followed by drying to obtain modified nano-alloy powder;

[0110] 2) crushing calcareous dolomite into 300-mesh fine powder, and then premixing the powder with dioctyl phthalate to prepare a dispersion having a solid content of 65 wt %, i.e., a composite slurry;

[0111] 3) PVC resin, microcrystalline wax with a molecular weight of 500, and modified nano-alloy powder were mixed in a mass ratio of 100:1.25:2 and dry-mixed at 85° C. for 8 min, followed by adding the compound slurry in an amount of 15 g / 100 g PVC resin, adding a calcium zinc stabilizer in an amount of 2.0 g / 100 g PVC resin, and adding an organic tin stabilizer in an amount of 0.5 g / 100 g PVC resin, and pre-mixing at 165° C. for 10 min, and then adding dicumyl peroxide in an amount of 2.0 g / 100 g PVC resin and mixing at 185° C. for 8 min to obtain a mixture;

[0112] 4) Adding AC foaming agent to the mixture at a ratio of 0.8 g / 100 g PVC resin, performing final mixing at 195° C. for 3 min, and then applying a pressure of 30 MPa at 55° C. for 5 min to form a stone-plastic composite floor.

[0113] The stone-plastic composite flooring produced in this example was characterized for specific gravity, surface porosity (front and back sides only), surface roughness Ra (front and back sides only), Taber abrasion test, surface hardness (front and back sides only), impact strength, sound insulation, thermal insulation, and crack resistance. The characterization methods were the same as in Example 1.

[0114] The specific characterization results are shown in the following table.

[0115] <![CDATA[Specific gravity (g / cm 3 )]]> Surface opening rate (%) Surface roughness Ra Taber abrasion Surface Shore hardness D 1.69 9.6 2.6μm 11.2 81 <![CDATA[Impact strength (kJ / m 2 )]]> Sound insulation A(dB) Sound insulation B (dB) Thermal conductivity Cracking resistance 11.8 11 23 0.098 excellent

[0116] The above characterization results clearly show that without gradient hot pressing, the surface porosity of the stone-plastic composite flooring increased dramatically, its smoothness decreased, and its overall wear resistance and hardness were inferior to those of the sample treated with gradient hot pressing. However, its impact strength and cracking resistance were retained, primarily due to its internal structure. On the other hand, due to the increased porosity, its sound and heat insulation properties also decreased significantly, indicating that the gradient hot pressing process plays a crucial role in stabilizing and optimizing the performance of the board. However, it should be noted that if the temperature used in the first hot pressing stage is too low, it will fail to stimulate localized thermal activation on the surface, resulting in poor treatment results. For example, if only a hot pressing stage temperature of 165°C is used, with all other conditions remaining the same, the surface porosity will reach 8.2%, and its overall performance will be far inferior to the superior sample in Example 1.

[0117] Comparative Example 4

[0118] A method for preparing a stone-plastic composite floor, comprising:

[0119] 1) placing 300-mesh CSZ532 alloy powder in a 2 wt% KH550-ethanol solution and subjecting it to a thermosonic modification treatment at 60° C. for 60 min, followed by drying to obtain modified nano-alloy powder;

[0120] 2) Premixing 300-mesh calcium carbonate micropowder and dioctyl phthalate to prepare a dispersion having a solid content of 65 wt %, i.e., a compound slurry;

[0121] 3) PVC resin, microcrystalline wax with a molecular weight of 500, and modified nano-alloy powder were mixed in a mass ratio of 100:1.25:2 and dry-mixed at 85° C. for 8 min, followed by adding the compound slurry in an amount of 15 g / 100 g PVC resin, adding a calcium zinc stabilizer in an amount of 2.0 g / 100 g PVC resin, and adding an organic tin stabilizer in an amount of 0.5 g / 100 g PVC resin, and pre-mixing at 165° C. for 10 min, and then adding dicumyl peroxide in an amount of 2.0 g / 100 g PVC resin and mixing at 185° C. for 8 min to obtain a mixture;

[0122] 4) adding an AC foaming agent to the mixture at a ratio of 0.8 g / 100 g of PVC resin, performing final mixing at 195 ° C for 3 minutes, and then applying a pressure of 30 MPa at 55 ° C for 5 minutes to obtain a pre-plate. The front and back sides of the pre-plate are processed in sequence, including a pressurization stage, a pressure release stage, and a pressure holding stage. The pressurization stage controls the hot pressing temperature to 185 ° C, the hot pressing pressure is 12 MPa, and the pressing time is 120 seconds. In the pressure release stage, the temperature is quickly cooled to 155 ° C and the pressing is directly released. The pressure release stage is maintained for 45 seconds. The temperature is controlled to 50 ° C in the pressure holding stage, the pressing pressure is 12 MPa, and the pressing time is 5 minutes. After completion, the pressing is released and cooled to room temperature to obtain a stone plastic composite floor.

[0123] The stone-plastic composite flooring produced in this example was characterized for specific gravity, surface porosity (front and back sides only), surface roughness Ra (front and back sides only), Taber abrasion test, surface hardness (front and back sides only), impact strength, sound insulation, thermal insulation, and crack resistance. The characterization methods were the same as in Example 1.

[0124] The specific characterization results are shown in the following table.

[0125]

[0126]

[0127] It can be clearly seen from the above characterization results that in the preparation process of this example, the calcium carbonate is used to replace the calcareous dolomite powder in the technical solution of the present invention, and most of the properties have declined, and the decline is relatively controllable. However, in terms of impact strength and crack resistance, a very significant decline has occurred. This is mainly because calcium carbonate powder is more likely to produce agglomeration and local stress concentration than calcareous dolomite powder, which leads to easy cracking and fracture under external force impact or hot and cold shock conditions. Therefore, the preparation effect of calcareous dolomite is better and the cost is lower. Although an additional grinding and milling process is required, the outsourcing cost of this process is low. Even if it is processed by itself, the difficulty and cost are relatively controllable, and the overall cost performance is still high.

Claims

1. A method for preparing a stone-plastic composite floor, characterized in that: The method comprises: 1) placing the nano alloy powder in a pretreatment solution for thermal ultrasonic modification to obtain modified nano alloy powder; 2) crushing the calcareous dolomite into fine powder, and then premixing the fine powder with an oily plasticizer to prepare a compound slurry; 3) mixing the PVC resin, lubricant and modified nano alloy powder and performing dry mixing at low temperature, then adding the compound slurry and stabilizer and premixing at elevated temperature, and then adding the cross-linking agent and performing high temperature mixing to obtain a mixture; 4) Adding a foaming agent to the mixture for final mixing and then pressing the mixture into sheets to obtain a pre-sheet, and subjecting the pre-sheet to a gradient hot pressing treatment to obtain a stone-plastic composite floor.

2. The method for preparing a stone-plastic composite floor according to claim 1, wherein: Step 1) The nano alloy powder is CSZ532 alloy powder, and its mesh number is ≥300 mesh; Step 1) The pretreatment liquid is a KH550-ethanol solution with a KH550 concentration of 1 to 3 wt%; In step 1), the thermal ultrasonic modification treatment is performed at 55-65° C. for 50-70 minutes, and the modified nano alloy powder is obtained after drying.

3. The method for preparing a stone-plastic composite floor according to claim 1, wherein: In step 2), the mass ratio of CaO to MgO in the calcareous dolomite after conversion is (2-2.5):1, and the calcium and / or magnesium components in the calcareous dolomite account for 95wt% or more of its total mass.

4. The method for preparing a stone-plastic composite floor according to claim 1 or 3, characterized in that: Step 2) the micro powder mesh size is 200-300 mesh; In step 2), the oily plasticizer is dioctyl phthalate, and the premixing process is to disperse the micropowder in the oily plasticizer and perform ultrasonic-assisted dispersion to prepare a dispersion with a solid content of 60-70 wt %, which is the compound slurry.

5. The method for preparing a stone-plastic composite floor according to claim 1, characterized in that: Step 3) The lubricant is a microcrystalline wax with a molecular weight of 400 to 600; Step 3) The mass ratio of the PVC resin, lubricant and modified nano alloy powder is 100: (1.0-1.5): (1.5-2.5); The low-temperature dry mixing process in step 3) is to stir and mix at 80-90° C. for 5-10 minutes.

6. The method for preparing a stone-plastic composite floor according to claim 1, characterized in that: Step 3) The amount of the compounded slurry is 15-20 g / 100 g PVC resin; Step 3) The stabilizer is a mixture of a calcium zinc stabilizer and an organotin stabilizer, wherein the amount of the calcium zinc stabilizer is 1.8 to 2.2 g / 100 g PVC resin, and the amount of the organotin stabilizer is 0.3 to 0.7 g / 100 g PVC resin; In step 3), the heating premixing is performed by stirring the premixing at 160-170° C. for 10-12 minutes.

7. The method for preparing a stone-plastic composite floor according to claim 1, characterized in that: Step 3) The cross-linking agent is dicumyl peroxide, and the amount thereof is 1.5 to 2.5 g / 100 g PVC resin; The high temperature mixing in step 3) is performed at 180-190° C. for 8-10 minutes.

8. The method for preparing a stone-plastic composite floor according to claim 1, characterized in that: Step 4) The foaming agent is AC foaming agent, and its usage is 0.5-1.0g / 100g PVC resin; Step 4) The temperature of the final mixing process is controlled at 190-195° C., the mixing time is 6-10 minutes, and then a pressure of 20-35 MPa is applied at 40-60° C. and maintained for 2-5 minutes to form a pre-sheet.

9. The method for preparing a stone-plastic composite floor according to claim 1 or 8, characterized in that: Step 4) The gradient hot pressing treatment is performed on both sides of the pre-sheet, and includes a pressurization stage, a pressure release stage, and a pressure holding stage in sequence; During the pressurization stage, the hot pressing temperature is controlled to be 180-185°C, the hot pressing pressure is controlled to be 10-15 MPa, and the pressing time is controlled to be 60-120 seconds; During the pressure release stage, the temperature is controlled to drop to 150-155°C and the pressure is directly released, and the pressure release stage is maintained for 30-60 seconds; During the pressure holding stage, the temperature is controlled to be reduced to 40-60° C., the pressing pressure is 10-15 MPa, and the pressing time is 3-5 minutes. After completion, the pressing is released and the stone-plastic composite floor is obtained after cooling to room temperature.

10. A stone-plastic composite floor produced by the method according to any one of claims 1 to 9.

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