A polystyrene foamed article and a method for producing the same
By combining chemical and physical foaming agents in polystyrene foam products, a uniform and fine cell structure is formed, which solves the problems of large environmental impact and insufficient compressive strength in the existing technology, and realizes the preparation of efficient and stable polystyrene foam materials.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGBO INST OF MATERIALS TECH & ENG CHINESE ACAD OF SCI
- Filing Date
- 2023-04-27
- Publication Date
- 2026-07-07
AI Technical Summary
Existing technologies for preparing polystyrene foam materials have significant environmental impacts, insufficient compressive strength, and difficulty in meeting the performance requirements of high-standard safety helmets. Furthermore, traditional methods require sophisticated equipment, involve complex processes, and are costly.
By combining chemical and physical foaming agents, a uniform cell structure is formed in the polystyrene matrix. The chemical foaming agent generates gas, which, combined with the physical changes of the physical foaming agent, forms fine cells, thus controlling the cell diameter and density.
This invention achieves high compressive strength polystyrene foam products with uniform and high-density cells, suitable for safety helmet lining materials, and reduces water usage in the preparation process, improving production efficiency and dimensional stability of the products.
Smart Images
Figure CN116535780B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of foamed plastic products, and relates to a polystyrene foamed product and its preparation method, particularly to a high-compression-strength polystyrene foamed product and its preparation method. Background Technology
[0002] Expandable polystyrene (EPS) is lightweight, inexpensive, and possesses excellent thermal insulation, sound insulation, and shock absorption properties. It is commonly used in packaging, construction, and transportation industries and is one of the three major polystyrene resin products (GPPS, HIPS, and EPS). There are generally two methods for preparing expandable polystyrene: one-step and two-step methods. The one-step method (suspension EPS) is mostly used to produce white expandable polystyrene, while the two-step method (impregnation EPS) is used to produce modified expandable polystyrene, including flame-retardant expandable polystyrene, colored expandable polystyrene, and antistatic expandable polystyrene. The suspension method requires a large amount of water, which has a significant environmental impact, and the molded products produced cannot meet high-standard requirements.
[0003] To better inspect for cracks, black expandable polystyrene (EPS) is used as a primary material, such as in safety helmets, and requires excellent compressive strength. Traditional helmets use a suspension method to produce white EPS, which is then coated with a surface coating to obtain black EPS. However, this method not only has a significant environmental impact, but its compressive and impact resistance also fails to meet the performance requirements of safety helmets.
[0004] To further improve EPS performance, researchers have conducted a series of studies to modify EPS. For example, patent CN 110343342 A directly uses an extruder to co-extrude and granulate a polystyrene composition with a foaming agent to obtain expandable polystyrene granules. However, this method requires a metering pump in the middle to inject the foaming agent into the extruder, placing high demands on equipment and process stability. Patent CN101353439 A adds styrene monomers and other aromatics during the impregnation process to improve the dispersion of fillers in polystyrene, achieving the preparation of high-performance expandable polystyrene materials. However, this method is relatively complex and costly. No reports have been found on improving the compressive strength of EPS by modifying the cell morphology.
[0005] For example, the prior art document (CN102161774A) also discloses other foaming agents, including physical foaming agents and chemical foaming agents. In the extrusion process, physical foaming agents and chemical foaming agents are added at the same time to obtain expanded polystyrene extruded boards. This method has high requirements for extrusion equipment and is not suitable for the production of expanded polystyrene irregular products. Summary of the Invention
[0006] The purpose of this invention is to address the aforementioned problems in the prior art by providing a polystyrene foam product with high compressive strength and a more uniform and finer cell structure.
[0007] To achieve the above-mentioned objectives, the present invention is implemented through the following scheme: a polystyrene foamed product, wherein the raw materials of the foamed product include a polystyrene modified system composed of polystyrene, a chemical foaming agent, a foaming aid, and a toughening agent, and a physical foaming system composed of water, a physical foaming agent, and a dispersant, wherein the average diameter of the foamed product is less than 50 μm.
[0008] The polystyrene foam products of the present invention contain both chemical foaming agents and physical foaming systems. The chemical foaming agent produces gases such as carbon dioxide or nitrogen through thermal decomposition, thereby forming cells in the polymer matrix. The added physical foaming agent is produced through changes in the physical form of the foaming agent, such as the expansion of compressed gas, the evaporation of liquid, or the dissolution of solid.
[0009] Preferably, the polystyrene is general-purpose polystyrene (GPPS); the melt index of the general-purpose polystyrene is 3-15 g / 10 min (200℃, 5 kg).
[0010] In the above-mentioned polystyrene foamed products, the chemical foaming agent accounts for 0.1% to 1% of the mass of polystyrene.
[0011] In the above-mentioned polystyrene foamed products, the foaming agent accounts for 0.1% to 1% of the mass of polystyrene.
[0012] Preferably, the mass ratio of chemical foaming agent to foaming aid is (1-10):1.
[0013] Preferably, the chemical foaming agent is one or more of azodicarbonamide, potassium azodicarbonamide formate, dinitrosopeptimide, p-toluenesulfonyl azide, and ethanolamine.
[0014] Preferably, the foaming agent is one or more of zinc nitrate, lead stearate, lauric acid, maleic anhydride, phthaloyl chloride, and stearoyl chloride.
[0015] In the above-mentioned polystyrene foamed products, the physical foaming agent accounts for 4 to 10% of the mass of the polystyrene modified system in the physical foaming system.
[0016] Preferably, the mass ratio of physical foaming agent to chemical foaming agent is (5-100):1. If the ratio of physical foaming agent to chemical foaming agent is too high, that is, too much physical foaming agent, it is not conducive to the formation of small and uniform cells; if the ratio is too low, that is, too much chemical foaming agent, it will cause the particles to shrink and the cell size to be unstable.
[0017] In the above-mentioned polystyrene foamed products, water and dispersant account for 150-200% and 1-2% of the mass of the polystyrene modified system, respectively, in the physical foaming system.
[0018] Preferably, the physical foaming agent is pentane.
[0019] Further preferably, the pentane is a mixed solvent of n-pentane and isopentane, with a mass ratio of n-pentane to isopentane of 1:(0.5-1). Excessive n-pentane content will increase molding pressure, which is detrimental to energy conservation; excessive isopentane content will increase cooling time during molding, reducing production efficiency and negatively impacting the dimensional stability of the molded body.
[0020] The dispersant is a mixture of inorganic and organic dispersants, with a mass ratio of inorganic to organic dispersant of 1:(10-30).
[0021] Further preferably, the inorganic dispersant is one or more of kaolin, montmorillonite, alkali metal phosphate, nano clay, and tricalcium phosphate.
[0022] More preferably, the organic dispersant is one or more of sodium benzenesulfonate, glyceryl monostearate, calcium stearate, stearamide, and polyvinyl alcohol.
[0023] In the above-mentioned polystyrene foam products, the toughening agent accounts for 0.5% to 2% of the mass of polystyrene.
[0024] Preferably, the toughening agent is one or more of ethylene propylene rubber, nitrile rubber, styrene-butadiene thermoplastic elastomer (SBS), and acrylonitrile-butadiene-styrene copolymer (ABS).
[0025] In the aforementioned polystyrene foam products, the polystyrene modification system also includes other additives, such as one or more of carbon black, graphite, carbon nanotubes, iron oxide red, and red lead.
[0026] In the above-mentioned polystyrene foam products, the average cell diameter is 20–50 μm; the cell density is 10. 8 ~10 13 pcs / cm 3 The 50% compressive strength of the foamed product is 0.5–2.0 MPa, and the density of the foamed product is 0.06–0.12 g / cm³. 3 .
[0027] Another object of the present invention is to provide a method for preparing the above-mentioned polystyrene foamed product, the method comprising the following steps:
[0028] S1. Weigh the raw materials for the foamed product, mix polystyrene, chemical foaming agent, foaming aid and toughening agent, melt-blend and extrude in an extruder, and granulate to obtain modified polystyrene microparticles;
[0029] S2. The physical foaming system consisting of water, physical foaming agent, and dispersant, along with the microparticles obtained in step S1, is added to a reaction vessel. Under saturated gas conditions, the mixture is pressurized, heated, and stirred. After saturation, the mixture is cooled and removed. The microparticles are then pre-expanded and molded to obtain polystyrene foamed products.
[0030] The present invention adds a small amount of chemical foaming agent during the extrusion process, forming a microporous structure in the polymer matrix. This is beneficial for increasing the solubility of pentane in the polymer matrix during impregnation and forming more heterogeneous nucleation sites, and for forming a uniform and high-density cell structure in the subsequent pre-expansion process.
[0031] Preferably, the extruder melting temperature in step S1 is 150–200°C.
[0032] Preferably, the modified polystyrene microparticles have a length of 1.5–3 mm, a diameter of 0.5–1.5 mm, and an aspect ratio of (1.5–3):1.
[0033] Preferably, the saturated gas in step S2 is one or more of air, nitrogen, and carbon dioxide.
[0034] Preferably, the pressurization pressure in step S2 is 0.5 to 1.5 MPa.
[0035] Preferably, the heating temperature in step S2 is 100–140°C.
[0036] Preferably, step S2 is carried out while stirring until the particles are removed.
[0037] Preferably, the temperature at which the particles are removed in step S2 is 30–50°C.
[0038] Preferably, the immersion time in the reactor in step S2 is 3 to 6 hours. The immersion time is the time from when the physical foaming system consisting of water, physical foaming agent, and dispersant, and the microparticles obtained in step S1 are added to the reactor until the particles are removed.
[0039] Preferably, the pre-expansion temperature is 80–130°C, and the pre-expansion time is 30–300 seconds. The bulk density of the pre-expanded foamed beads is 60–120 g / L.
[0040] Preferably, the steam pressure during molding is 0.5-1.5 bar, and the molding time is 10-30 seconds.
[0041] Preferably, the process includes curing after pre-expansion and before molding. Curing is carried out at room temperature for 24 to 200 hours.
[0042] The above-mentioned polystyrene foam products of the present invention are used in safety helmets, thermal insulation materials, packaging materials, and building materials.
[0043] Compared with the prior art, the present invention has the following advantages:
[0044] 1. Existing technologies using a single chemical foaming agent are not suitable for the preparation of irregularly shaped products, while using a single physical foaming agent will result in low compressibility. The present invention contains both a chemical foaming agent and a physical foaming agent in the polystyrene matrix. The chemical foaming agent decomposes thermally to produce gases such as carbon dioxide or nitrogen, thereby forming cells in the polymer matrix; while the added physical foaming agent works by changing the physical form of the foaming agent, such as the expansion of compressed gas, the evaporation of liquid, or the dissolution of solid.
[0045] 2. In this invention, a small amount of chemical foaming agent is added first, which partially decomposes during the extrusion process to form more small molecules, thereby creating more heterogeneous nucleation sites in the PS matrix and forming a microporous structure in the polymer matrix. This is beneficial for increasing the solubility of the physical foaming agent added later in the polymer matrix during the impregnation process and forming more heterogeneous nucleation sites. Furthermore, it helps to form a uniform cell structure with high cell density during the subsequent pre-expansion process.
[0046] 3. By controlling the ratio of physical foaming agents, this invention controls the dimensional stability of the molded products, resulting in foamed beads with a more uniform and finer cell structure, an average cell diameter of less than 50 μm, and more stable molded product dimensions. It also improves production efficiency, makes the preparation process stable, safe and controllable, and reduces the amount of water required during the preparation process.
[0047] 4. The polystyrene foam products of the present invention have excellent compressive strength, uniform cell distribution, high cell density, high intercellular compressive strength and good toughness, and are widely used. They can be used as lining materials for high-performance safety helmets, as well as for thermal insulation materials, packaging materials and building materials, etc. Attached Figure Description
[0048] Figure 1 This is a diagram showing the cell structure of a cross-section of the foamed beads in Example 1;
[0049] Figure 2 This is a diagram showing the cell structure of a cross-section of the molded product from Example 1;
[0050] Figure 3 The cell structure diagram is shown in the cross-section of the foamed product of Comparative Example 1.
[0051] Figure 4This is a diagram of the cell structure of a cross-section of the molded product in Comparative Example 1. Detailed Implementation
[0052] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the high-compression-strength black polystyrene foam material and its preparation method provided by the present invention. However, the specific material ratios, process parameters, and results described in the embodiments are merely illustrative of the invention and should not, and will not, limit the invention as described in detail in the claims.
[0053] Unless otherwise specified, the raw materials used in the embodiments of this application were all purchased through commercial channels. Unless otherwise specified, the testing methods were all conventional methods, and the instrument settings were all the settings recommended by the manufacturer.
[0054] The testing method involved in this invention:
[0055] The internal cell structure of foamed beads and molded product cross-sections: Analysis was performed using a scanning electron microscope (SEM) specifically an EVO18 large-cavity SEM from ZEISS GmbH, Germany. The analytical method involved analyzing the cross-sections of the prepared foamed beads and molded product samples. The average cell size (d) was determined. n The unit is μm, and the unit of bubble density (N0) is cells / cm³. 3 The calculation method is as follows:
[0056]
[0057] (Formula 1)
[0058]
[0059] (Formula 2)
[0060]
[0061] (Formula 3)
[0062] In the formula, d i Equivalent bubble diameter;
[0063] n i The number of bubbles with an equivalent diameter of di;
[0064] n is the number of bubbles in the SEM image;
[0065] M is the magnification factor of the SEM image;
[0066] A is the area of the SEM image (cm²) 2 );
[0067] φ represents the expansion ratio of the foaming material;
[0068] ρ0 is the density of the sample before foaming;
[0069] ρ f The density of the sample after foaming.
[0070] Bulk density of foamed beads: Pour the prepared foamed beads into a 1L graduated cylinder, smooth the surface of the graduated cylinder, and weigh the mass of the foamed beads in the graduated cylinder. During the experiment, the sample should be kept in a loose state to prevent any degree of vibration. The mass of foamed beads per unit volume can then be obtained, and the unit is g / L.
[0071] Compressive strength of molded products: The Instron 5567 universal testing machine was used, and the test method was GB 8813-2008. The material compression performance was tested at a compression rate of 5 mm / min, and the unit is MPa.
[0072] Raw materials for foamed products in Examples 1-5 and Comparative Examples 1-3
[0073]
[0074]
[0075] Example 1
[0076] According to the mass proportions described in Table 1 Example 1, 6 parts by weight of polystyrene, chemical foaming agent, foaming aid, toughening agent and carbon black were weighed, mixed and then melt-blended and extruded in an extruder, and granulated to obtain modified polystyrene microparticles.
[0077] Then, water, physical foaming agent, and dispersant are weighed and added to a reaction vessel to form a physical foaming system. 100 parts by weight of modified polystyrene microparticles are added to the reaction vessel and heated to 1.5 MPa and 120°C under saturated nitrogen gas. After saturation for 5 hours, the mixture is cooled down. When the temperature drops to 50°C, the particles are taken out. Stirring is carried out during the pressurization and heating process until the particles are taken out and the stirring is turned off.
[0078] The extracted particles were first air-dried, then pre-expanded at 110℃ for 60 seconds to obtain foamed beads with a bulk density of 80 g / L. These beads were then cured at room temperature for 48 hours. Figure 1 The image shows a cross-section of the foamed beads, indicating a uniform distribution of cell size.
[0079] The foamed beads are passed through a steam molding machine at a steam pressure of 1.0 bar for 20 seconds to obtain polystyrene foam products. Figure 2 The image shows a cross-section of the molded product. The particles are uniformly distributed and the bonding between the particle interfaces is complete. The average cell diameter of the polystyrene foam product is 35 μm, and the cell density is 5.0 × 10⁻⁶. 11 pcs / cm 3After compression testing with a universal testing machine, the 50% compressive strength is 1.06 MPa.
[0080] Example 2
[0081] According to the mass proportions described in Table 1 Example 2, 6 parts by weight of polystyrene, chemical foaming agent, foaming aid, toughening agent and carbon black were weighed, mixed and then melt-blended and extruded in an extruder, and granulated to obtain modified polystyrene microparticles.
[0082] Then, water, physical foaming agent, and dispersant are weighed and added to a reaction vessel to form a physical foaming system. 100 parts by weight of modified polystyrene microparticles are added to the reaction vessel and heated to 1.2 MPa and 115°C under saturated nitrogen gas. After saturation for 5 hours, the mixture is cooled down. When the temperature drops to 50°C, the particles are taken out. Stirring is carried out during the pressurization and heating process until the particles are taken out and the stirring is turned off.
[0083] The extracted particles were first air-dried naturally, then pre-expanded at 100℃ for 60 seconds to obtain foamed beads with a bulk density of 90 g / L, and then cured at room temperature for 48 hours.
[0084] The foamed beads are passed through a steam molding machine with a steam pressure of 1.2 bar and a molding time of 25 seconds to obtain polystyrene foam products.
[0085] The average cell diameter of polystyrene foam products is 25 μm, and the cell density is 6.1 × 10⁻⁶. 12 pcs / cm 3 After compression testing with a universal testing machine, the 50% compressive strength is 1.30 MPa.
[0086] Example 3
[0087] The raw materials were weighed according to the mass fractions described in Table 1 Example 3, and prepared according to the preparation method in Example 1. During the preparation process, the materials were heated to 1.0 MPa and 110°C under saturated nitrogen gas. After saturation for 5 hours, the materials were cooled down and the particles were removed when the temperature dropped to 50°C.
[0088] The extracted particles were first air-dried naturally, then pre-expanded at 100℃ for 100s to obtain foamed beads with a bulk density of 85g / L, and then cured at room temperature for 48 hours.
[0089] The foamed beads are passed through a steam molding machine with a steam pressure of 1.0 bar and a molding time of 20 seconds to obtain polystyrene foam products.
[0090] The average cell diameter of polystyrene foam products is 30 μm, and the cell density is 7.2 × 10⁻⁶. 11 pcs / cm 3 After compression testing with a universal testing machine, the 50% compressive strength is 1.15 MPa.
[0091] Example 4
[0092] The raw materials were weighed according to the mass fractions described in Table 1 Example 4 and prepared according to the preparation method in Example 1. During the preparation process, the materials were pressurized and heated to 1.1 MPa and 110°C under saturated nitrogen gas. After saturation for 5 hours, the materials were cooled down and the particles were removed when the temperature dropped to 50°C.
[0093] The extracted particles were first air-dried naturally, then pre-expanded at 100℃ for 120s to obtain foamed beads with a bulk density of 80g / L, and then cured at room temperature for 48 hours.
[0094] The foamed beads are passed through a steam molding machine with a steam pressure of 1.0 bar and a molding time of 20 seconds to obtain polystyrene foam products.
[0095] The average cell diameter of polystyrene foam products is 30 μm, and the cell density is 3.5 × 10⁻⁶. 11 pcs / cm 3 After compression testing with a universal testing machine, the 50% compressive strength is 1.08 MPa.
[0096] Example 5
[0097] The raw materials were weighed according to the mass proportions described in Example 5 of Table 1, and prepared according to the preparation method in Example 4. The bulk density of the foamed beads was 100 g / L, the average cell diameter of the polystyrene foam product was 20 μm, and the cell density was 1.0*10. 13 pcs / cm 3 After compression testing with a universal testing machine, the 50% compressive strength is 1.40 MPa.
[0098] Example 6
[0099] The only difference between this example and Example 1 is the use of 0.05 parts of azodicarbonamide in Example 6. The foamed beads were prepared according to the method described in Example 1, resulting in a bulk density of 85 g / L, an average cell diameter of 50 μm, and a cell density of 1.0 × 10⁻⁶. 10 pcs / cm 3 After compression testing with a universal testing machine, the 50% compressive strength is 1.10 MPa.
[0100] Example 7
[0101] The only difference between this example and Example 1 is the addition of 2 parts azodicarbonamide in Example 7. The mixture was then prepared according to the method described in Example 1, resulting in foamed beads with a bulk density of 75 g / L, polystyrene foam with an average cell diameter of 100 μm, and a cell density of 2.5 x 10⁻⁶. 8 pcs / cm3 After compression testing with a universal testing machine, the 50% compressive strength is 0.75 MPa.
[0102] Example 8
[0103] The only difference between the raw materials and those in Example 1 is that in Example 8, the physical foaming agent is 1 part n-pentane and 1 part isopentane. Then, the foaming beads are prepared according to the preparation method in Example 1. The bulk density of the foamed beads is 150 g / L. The content of the physical foaming agent is too low, so it is impossible to obtain a lower bulk density and it is not easy to form.
[0104] Example 9
[0105] The only difference between Example 9 and Example 1 is that the physical foaming agent in Example 9 is 6 parts n-pentane and 6 parts isopentane. The foaming process was then carried out according to the method described in Example 1, resulting in foamed beads with a bulk density of 45 g / L, polystyrene foam with an average cell diameter of 150 μm, and a cell density of 2.1*10⁻⁶. 7 pcs / cm 3 The product underwent compression testing on a universal testing machine, with a 50% compressive strength of 0.35 MPa. The excessively high content of physical foaming agent made it impossible to control the product's density during the manufacturing process.
[0106] Example 10
[0107] The only difference between Example 9 and Example 1 is that the physical foaming agent in Example 9 is 5 parts of n-pentane. The foaming process was then carried out according to the method described in Example 1, resulting in foamed beads with a bulk density of 80 g / L, an average cell diameter of 40 μm in the polystyrene foam product, and a cell density of 7.0 x 10⁻⁶. 10 pcs / cm 3 The compression strength was 0.95 MPa at 50% after compression testing on a universal testing machine. Increasing the n-pentane content resulted in a corresponding increase in molding pressure, but compared to Example 1, the same molding pressure yielded a worse molded product with lower compressive strength.
[0108] Example 11
[0109] Weigh the raw material components from Example 1, and mix polystyrene, chemical foaming agent, foaming aid, toughening agent, and carbon black. Add the mixture to an extruder, and add pentane in the middle section of the extruder. Pelletize to obtain modified polystyrene microparticles. Pre-expand the microparticles at 110°C for 60 seconds to obtain foamed beads with a bulk density of 80 g / L. After curing at room temperature for 48 hours, mold the product. The average cell size of the polystyrene foamed product is 50 μm, and the cell density is 7.1 × 10⁻⁶. 10 pcs / cm 3 The 50% compressive strength is 0.98 MPa.
[0110] Comparative Example 1
[0111] The raw materials were weighed according to the mass proportions described in Comparative Example 1 in Table 1, and prepared according to the preparation method in Example 1 to obtain foamed beads with a bulk density of 82 g / L. Figure 3 The image shown is a SEM image of a cross-section of the foamed beads in Comparative Example 1, revealing an uneven distribution of cell size. The final product obtained is a polystyrene molded product. Figure 4 This is a SEM image of a cross-section of a polystyrene molded product. The particle uniformity is poor, resulting in unsatisfactory molding performance. The average cell size of the polystyrene foam product is 350 μm, and the cell density is 2.1 x 10⁻⁶. 6 pcs / cm 3 After compression testing with a universal testing machine, the 50% compressive strength is 0.90 MPa.
[0112] Comparative Example 2
[0113] The raw materials were weighed according to the mass proportions described in Comparative Example 2 of Table 1, and prepared according to the preparation method in Example 1 to obtain foamed beads with a bulk density of 95 g / L. Finally, polystyrene molded products were obtained. The average cell diameter of the polystyrene foamed products was 200 μm, and the cell density was 3.8 × 10⁻⁶. 7 pcs / cm 3 After compression testing with a universal testing machine, the 50% compressive strength is 1.06 MPa.
[0114] Comparative Example 3
[0115] The raw materials were weighed according to the mass fractions described in Comparative Example 3 in Table 1, and prepared according to the preparation method in Example 1. No pentane was added during the impregnation process, and the particles did not foam during the pre-expansion process, so foamed products could not be obtained.
[0116] In summary, this invention incorporates both chemical and physical foaming agents into the polystyrene matrix. A small amount of the chemical foaming agent partially decomposes during extrusion, forming more small molecules. This results in more heterogeneous nucleation sites within the PS matrix and the formation of a microporous structure. This also improves the solubility of the physical foaming agent in the polymer matrix and facilitates the formation of a uniform and high-density cell structure during subsequent pre-expansion. Furthermore, by controlling the proportion of the physical foaming agent, this invention controls the dimensional stability of the molded product, resulting in foamed beads with a more uniform and finer cell structure, an average cell diameter of less than 50 μm, and more stable dimensions and superior compressive strength. Simultaneously, it improves production efficiency, makes the preparation process stable, safe, and controllable, and reduces the water requirement during preparation.
[0117] The above are specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A polystyrene foam product, characterized in that, The raw materials of the foamed product include a polystyrene modified system composed of polystyrene, chemical foaming agent, foaming aid, and toughening agent, and a physical foaming system composed of water, physical foaming agent, and dispersant. The average diameter of the foamed product is less than 50 μm. The chemical foaming agent is one or more of azodicarbonamide, potassium azodicarbonamide formate, dinitrosopeptimethylenetetramine, p-toluenesulfonyl azide, and ethanolamine; the foaming aid is one or more of zinc nitrate, lead stearate, lauric acid, maleic anhydride, phthaloyl chloride, and stearoyl chloride. The chemical foaming agent accounts for 0.1-1% of the mass of polystyrene, and the foaming aid accounts for 0.1-1% of the mass of polystyrene, with a mass ratio of (1-10):1 between the chemical foaming agent and the foaming aid; The physical foaming agent is pentane, which is a mixed solvent of n-pentane and isopentane, with a mass ratio of n-pentane to isopentane of 1:(0.5~1). In the physical foaming system, the physical foaming agent accounts for 4-10% of the mass of the polystyrene modified system; The mass ratio of the physical foaming agent to the chemical foaming agent is (5~100):1; The method for preparing the polystyrene foam product includes the following steps: S1. Weigh the raw materials for the foamed product, mix polystyrene, chemical foaming agent, foaming aid and toughening agent, melt-blend and extrude in an extruder, and granulate to obtain modified polystyrene microparticles; S2. Add the physical foaming system consisting of water, physical foaming agent, and dispersant, and the microparticles obtained in step S1 into the reactor. Pressurize, heat, and stir under saturated gas. After saturation, cool down and remove the particles. After pre-expansion and molding, polystyrene foam products are obtained. In step S2, the pressure applied is 0.5~1.5MPa, the heating temperature is 100~140℃, the steam pressure during molding is 0.5~1.5bar, and the molding time is 10~30s.
2. The polystyrene foam product according to claim 1, characterized in that, The toughening agent in the polystyrene modification system accounts for 0.5-2% of the mass of polystyrene; the polystyrene modification system also includes other additives, which include one or more of carbon black, graphite, carbon nanotubes, iron oxide red, and red lead.
3. The polystyrene foam product according to claim 1, characterized in that, The average cell diameter of the polystyrene foam product is 20~50μm; the cell density is 10. 8 ~10 13 pcs / cm 3 The 50% compressive strength of the foamed product is 0.5~2.0 MPa, and the density of the foamed product is 0.06~0.12 g / cm³. 3 .
4. A method for preparing a polystyrene foamed product as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: S1. Weigh the raw materials for the foamed product, mix polystyrene, chemical foaming agent, foaming aid and toughening agent, melt-blend and extrude in an extruder, and granulate to obtain modified polystyrene microparticles; S2. The physical foaming system consisting of water, physical foaming agent, and dispersant, along with the microparticles obtained in step S1, is added to a reaction vessel. Under saturated gas conditions, the mixture is pressurized, heated, and stirred. After saturation, the mixture is cooled and removed. The microparticles are then pre-expanded and molded to obtain polystyrene foamed products.
5. The method for preparing polystyrene foamed products according to claim 4, characterized in that, In step S2, the pressure applied is 0.5~1.5MPa, the heating temperature is 100~140℃, the steam pressure during molding is 0.5~1.5bar, and the molding time is 10~30s.