A method for preparing impact-resistant polystyrene extruded board

Abstract

The present invention relates to the technical field of polystyrene, and discloses a preparation method of an impact-resistant polystyrene extruded sheet material, wherein 65-80 parts by weight of polystyrene resin, 20-35 parts by weight of wood flour, 5-15 parts by weight of modified SBS, 1.2-1.7 parts by weight of auxiliary agent, 2-4 parts by weight of flame retardant, etc. are mixed, extruded, and foamed to obtain an impact-resistant polystyrene extruded sheet material. The side chain of the modified SBS contains a carboxyl group, which can form a hydrogen bond interaction with the hydroxyl group on the surface of the wood flour, thereby improving the compatibility between the wood flour and the polystyrene resin, and is conducive to improving the mechanical properties of the extruded sheet material, showing higher impact strength and flexural strength. The modified SBS side chain introduces a triazole structure, forms a nitrogen-phosphorus flame retardant with triphenyl phosphate, and improves the limiting oxygen index and flame retardant properties of the extruded sheet material.

Description

Technical Field

[0001] The invention relates to the technical field of polystyrene, in particular to a method for preparing an impact-resistant polystyrene extruded plate. Background Art

[0002] Extruded polystyrene boards are lightweight, have low water absorption, offer excellent thermal insulation, and provide superior sound insulation, making them widely used in building materials, petrochemicals, and other fields. Traditional polystyrene boards suffer from low impact resistance and flammability. Blending polystyrene with wood flour can produce wood-plastic materials with excellent flame retardancy and high mechanical strength. To improve the compatibility of wood flour and polystyrene, the wood flour is typically modified with silane coupling agents, maleic anhydride, or a compatibilizer such as maleic anhydride-grafted polystyrene is added.

[0003] Adding elastomers to polystyrene sheets can improve their toughness, impact strength, and other properties. SBS (styrene-butadiene-styrene block copolymer) is a high-performance elastomer with a wide range of applications. Functional SBS materials can be obtained by reacting or grafting SBS with chloromethylating agents, maleic anhydride, acrylates, and other substances. Chinese patent CN109294087B discloses a modified polystyrene material and its preparation method. Using polystyrene, star-shaped SBS, and a core-shell toughening agent as raw materials, the resulting modified polystyrene exhibits advantages such as good impact strength and melt flowability. However, the modified polystyrene lacks flame retardancy. Summary of the Invention

[0004] Technical problem to be solved: The present invention provides a method for preparing an impact-resistant polystyrene extruded board, which solves the problem that the polystyrene extruded board is easy to burn and has low impact strength.

[0005] Technical solution: A method for preparing impact-resistant polystyrene extruded board:

[0006] (1) Chloromethylated SBS is added to the reaction solvent, and after stirring, 5-carboxy-3-amino-1,2,4-triazole and a catalyst are added, and the mixture is stirred for reaction. Ethanol is added to the solution for precipitation, and the mixture is filtered, washed with water and ethanol, and dried to obtain modified SBS.

[0007] (2) 65-80 parts by weight of polystyrene resin, 20-35 parts by weight of wood flour, 5-15 parts by weight of modified SBS, 1.2-1.7 parts by weight of auxiliary agent, 2-3 parts by weight of nucleating agent, 2-4 parts by weight of flame retardant, and 0.4-0.6 parts by weight of antioxidant are added into a mixer and mixed, and then extruded through a twin-screw extruder, and finally extruded and foamed in a single-screw extruder to obtain an impact-resistant polystyrene extruded board.

[0008] Furthermore, the auxiliary agent includes azodicarbonamide.

[0009] Furthermore, the nucleating agent includes talc.

[0010] Furthermore, the flame retardant includes triphenyl phosphate.

[0011] Furthermore, the antioxidant includes antioxidant 1010, antioxidant 1076 or antioxidant 168.

[0012] Furthermore, the reaction solvent in (1) includes toluene or xylene.

[0013] Furthermore, the reaction temperature in (1) is 80-110°C, and the reaction time is 24-36h.

[0014] Furthermore, the mass ratio of chloromethylated SBS, 5-carboxy-3-amino-1,2,4-triazole, and catalyst in (1) is 100:(20-70):(26-94).

[0015] Furthermore, the catalyst in (1) includes sodium carbonate or potassium carbonate.

[0016] Furthermore, (2) the temperature of zones 1-6 of the twin-screw extruder of the medium-screw extruder is 165-210°C, and the screw speed is 60-100 r / min. The temperature of zones 1-3 of the single-screw extruder is 150-180°C, and the screw speed is 50-80 r / min.

[0017] Furthermore, the preparation method of chloromethylated SBS is as follows: 100 parts by weight of SBS styrene-butadiene-styrene block copolymer and 12-30 parts by weight of tin chloride are added to toluene, 16-40 parts by weight of 1,4-bis(chloromethoxy)-butane are added dropwise after stirring, and the mixture is reacted at 15-20° C. for 4-6 hours. Ethanol is added to the solution for precipitation, and the mixture is filtered, washed with water, and dried to obtain chloromethylated SBS.

[0018] Beneficial technical effects: The present invention involves a substitution reaction between the chloromethyl group of chloromethylated SBS and the amino group of 5-carboxyl-3-amino-1,2,4-triazole to obtain a modified SBS, which is then extruded and foamed with a polystyrene resin, wood powder, a triphenyl phosphate flame retardant, and additives to produce an impact-resistant polystyrene extruded board. The modified SBS has a side chain containing carboxyl groups that can form hydrogen bonds with the hydroxyl groups on the surface of the wood powder, thereby allowing the modified SBS to be modified and coated on the surface of the wood powder. Since the SBS styrene-butadiene-styrene block copolymer has good compatibility with the polystyrene resin, the compatibility between the wood powder and the polystyrene resin is improved, and the interfacial strength between the two is enhanced, which is beneficial for improving the mechanical properties of the extruded board, exhibiting higher impact strength and flexural strength.

[0019] The triazole structure introduced into the modified SBS side chain of the present invention forms a nitrogen-phosphorus flame retardant with triphenyl phosphate, which generates nitrogen and other gases during combustion, promotes the formation of an expanded carbon layer in the extruded board, and improves the limiting oxygen index and flame retardancy of the extruded board. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the preparation reaction formula of modified SBS.

[0021] Figure 2 It is the infrared spectrum of modified SBS. DETAILED DESCRIPTION

[0022] The present invention will be further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto.

[0023] Example 1: (1) 200 g of SBS styrene-butadiene-styrene block copolymer and 24 g of tin chloride were added to 10 L of toluene, and 32 g of 1,4-bis(chloromethoxy)-butane was added dropwise after stirring. The mixture was reacted at 20°C for 4 h. Ethanol was added to the solution for precipitation. The mixture was filtered, washed with water, and dried to obtain chloromethylated SBS.

[0024] (2) Add 300 g of chloromethylated SBS to 10 L of toluene, heat to 100 °C, stir, add 60 g of 5-carboxy-3-amino-1,2,4-triazole and 78 g of potassium carbonate as a catalyst, stir and react for 24 h, add ethanol to the solution for precipitation, filter, wash with water and ethanol, and dry to obtain modified SBS. Figure 1 Middle 3424cm -1 and 1721cm -1 It is the absorption peak of hydroxyl -OH and carbonyl -C=O- in carboxyl group, 1450cm -1 It is the absorption peak of the -C=N- bond in triazole.

[0025] (3) 8 kg of polystyrene resin, 2 kg of poplar wood powder (average particle size 60 mesh), 1.5 kg of modified SBS, 170 g of auxiliary agent azodicarbonamide, 300 g of nucleating agent talc, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 were added to a mixer and mixed, and then extruded through a twin-screw extruder, with the temperatures of zones 1-6 being 165°C, 190°C, 200°C, 210°C, 210°C, and 205°C, and the screw speed being 100 r / min; finally, extrusion foaming was performed in a single-screw extruder, with the temperatures of zones 1-3 being 150°C, 180°C, and 170°C, and the screw speed being 80 r / min, to obtain impact-resistant polystyrene extruded board.

[0026] Example 2: (1) 200 g of SBS styrene-butadiene-styrene block copolymer and 40 g of tin chloride were added to 12 L of toluene, and 55 g of 1,4-bis(chloromethoxy)-butane was added dropwise after stirring. The mixture was reacted at 20°C for 5 h. Ethanol was added to the solution for precipitation. The mixture was filtered, washed with water, and dried to obtain chloromethylated SBS.

[0027] (2) Add 300 g of chloromethylated SBS to 11 L of xylene, heat to 80 °C, stir, add 130 g of 5-carboxy-3-amino-1,2,4-triazole and 170 g of potassium carbonate as a catalyst, stir and react for 36 h, add ethanol to the solution for precipitation, filter, wash with water and ethanol, and dry to obtain modified SBS.

[0028] (3) 7.5 kg of polystyrene resin, 2.5 kg of poplar wood powder (average particle size 60 mesh), 1 kg of modified SBS, 150 g of auxiliary agent azodicarbonamide, 260 g of nucleating agent talc, 0.3 kg of flame retardant triphenyl phosphate, and 40 g of antioxidant 168 were added to a mixer and mixed, and then extruded through a twin-screw extruder, with the temperatures of zones 1-6 being 165°C, 190°C, 200°C, 210°C, 210°C, and 205°C, and the screw speed being 60 r / min; finally, extrusion foaming was performed in a single-screw extruder, with the temperatures of zones 1-3 being 150°C, 180°C, and 170°C, and the screw speed being 80 r / min, to obtain impact-resistant polystyrene extruded sheets.

[0029] Example 3: (1) Add 200 g of SBS styrene-butadiene-styrene block copolymer and 60 g of tin chloride to 12 L of toluene, stir, add 80 g of 1,4-bis(chloromethoxy)-butane dropwise, react at 15°C for 6 h, add ethanol to the solution for precipitation, filter, wash with water, and dry to obtain chloromethylated SBS.

[0030] (2) Add 300 g of chloromethylated SBS to 13 L of toluene, heat to 110 °C, stir, add 210 g of 5-carboxy-3-amino-1,2,4-triazole and 282 g of sodium carbonate as a catalyst, stir and react for 30 h, add ethanol to the solution for precipitation, filter, wash with water and ethanol, and dry to obtain modified SBS.

[0031] (3) 6.5 kg of polystyrene resin, 3.5 kg of poplar wood powder (average particle size 60 mesh), 0.5 kg of modified SBS, 120 g of auxiliary agent azodicarbonamide, 200 g of nucleating agent talc, 0.2 kg of flame retardant triphenyl phosphate, and 40 g of antioxidant 1010 were added to a mixer and mixed, and then extruded through a twin-screw extruder, with the temperatures of zones 1-6 being 165°C, 190°C, 200°C, 210°C, 210°C, and 205°C, and the screw speed being 100 r / min; finally, extrusion foaming was performed in a single-screw extruder, with the temperatures of zones 1-3 being 150°C, 180°C, and 170°C, and the screw speed being 50 r / min, to obtain impact-resistant polystyrene extruded board.

[0032] Comparative Example 1: This comparative example differs from Example 1 in that SBS styrene-butadiene-styrene block copolymer is used instead of modified SBS.

[0033] (1) 8 kg of polystyrene resin, 2 kg of poplar wood powder (average particle size 60 mesh), 1.5 kg of SBS styrene-butadiene-styrene block copolymer, 170 g of auxiliary agent azodicarbonamide, 300 g of nucleating agent talc, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 were added to a mixer and mixed, and then extruded through a twin-screw extruder, with the temperatures of zones 1-6 being 165°C, 190°C, 200°C, 210°C, 210°C, and 205°C, and the screw speed being 100 r / min; finally, extruded and foamed in a single-screw extruder, with the temperatures of zones 1-3 being 150°C, 180°C, and 170°C, and the screw speed being 80 r / min, to obtain impact-resistant polystyrene extruded board.

[0034] Comparative Example 2: This comparative example differs from Example 1 in that chloromethylated SBS is used instead of modified SBS.

[0035] (1) 8 kg of polystyrene resin, 2 kg of poplar wood powder (average particle size 60 mesh), 1.5 kg of chloromethylated SBS, 170 g of auxiliary agent azodicarbonamide, 300 g of nucleating agent talc, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 were added to a mixer and mixed, and then extruded through a twin-screw extruder, with the temperatures of zones 1-6 being 165°C, 190°C, 200°C, 210°C, 210°C, and 205°C, and the screw speed being 100 r / min; finally, extruded and foamed in a single-screw extruder, with the temperatures of zones 1-3 being 150°C, 180°C, and 170°C, and the screw speed being 80 r / min, to obtain impact-resistant polystyrene extruded board.

[0036] Comparative Example 3: This comparative example differs from Example 1 in that 3-amino-1,2,4-triazole is used instead of 5-carboxyl-3-amino-1,2,4-triazole.

[0037] (1) Add 300 g of chloromethylated SBS to 10 L of toluene, heat to 100 °C, stir, add 60 g of 3-amino-1,2,4-triazole (CAS No. 61-82-5) and 78 g of potassium carbonate as a catalyst, stir and react for 24 h, add ethanol to the solution for precipitation, filter, wash with water and ethanol, and dry to obtain modified SBS.

[0038] (2) 8 kg of polystyrene resin, 2 kg of poplar wood powder (average particle size 60 mesh), 1.5 kg of modified SBS, 170 g of auxiliary agent azodicarbonamide, 300 g of nucleating agent talc, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 were added to a mixer and mixed, and then extruded through a twin-screw extruder, with the temperatures of zones 1-6 being 165°C, 190°C, 200°C, 210°C, 210°C, and 205°C, and the screw speed being 100 r / min; finally, extrusion foaming was performed in a single-screw extruder, with the temperatures of zones 1-3 being 150°C, 180°C, and 170°C, and the screw speed being 80 r / min, to obtain impact-resistant polystyrene extruded board.

[0039] Comparative Example 4: This comparative example differs from Example 1 in that β-aminopropionic acid is used instead of 5-carboxy-3-amino-1,2,4-triazole.

[0040] (1) Add 300 g of chloromethylated SBS to 10 L of toluene, heat to 100 °C, stir, add 60 g of β-aminopropionic acid (CAS No. 107-95-9) and 78 g of potassium carbonate as a catalyst, stir and react for 24 h, add ethanol to the solution for precipitation, filter, wash with water and ethanol, and dry to obtain modified SBS.

[0041] (2) 8 kg of polystyrene resin, 2 kg of poplar wood powder (average particle size 60 mesh), 1.5 kg of modified SBS, 170 g of auxiliary agent azodicarbonamide, 300 g of nucleating agent talc, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 were added to a mixer and mixed, and then extruded through a twin-screw extruder, with the temperatures of zones 1-6 being 165°C, 190°C, 200°C, 210°C, 210°C, and 205°C, and the screw speed being 100 r / min; finally, extrusion foaming was performed in a single-screw extruder, with the temperatures of zones 1-3 being 150°C, 180°C, and 170°C, and the screw speed being 80 r / min, to obtain impact-resistant polystyrene extruded board.

[0042] Simply supported beam impact strength is tested according to GB / T 1043.1-2008. Flexural strength is tested according to GB / T 9341-2008. Flame retardancy is tested according to GB / T 2406.2-2009.

[0043] Table 1 Performance test of polystyrene extruded board

[0044]

[0045] Examples 1-4 incorporate modified SBS, whose side chains contain carboxyl groups that can form hydrogen bonds with hydroxyl groups on the surface of wood powder, thereby modifying the modified SBS on the wood powder surface. Since the SBS styrene-butadiene-styrene block copolymer has good compatibility with polystyrene resin, this improves the compatibility between the wood powder and the polystyrene resin, enhancing the interfacial strength between the two, which helps improve the mechanical properties of the extruded board, exhibiting higher impact strength and flexural strength. Furthermore, the triazole structure introduced into the side chains of the modified SBS forms a nitrogen-phosphorus flame retardant with triphenyl phosphate. Upon combustion, the generated nitrogen and other gases dilute oxygen, promoting the formation of an expanded char layer in the extruded board, resulting in a better flame retardant effect and a higher limiting oxygen index.

[0046] Comparative Example 1 incorporated only standard SBS styrene-butadiene-styrene block copolymer, which lacks carboxyl groups and cannot form hydrogen bonds with the hydroxyl groups on the wood powder surface, failing to improve the compatibility between the wood powder and the polystyrene resin. Consequently, the extruded board exhibited low impact and flexural strength. Furthermore, the SBS styrene-butadiene-styrene block copolymer lacks a triazole structure, failing to form a nitrogen-phosphorus flame retardant system. This resulted in a low limiting oxygen index for the extruded board.

[0047] Comparative Example 2 incorporates chloromethylated SBS, which lacks carboxyl groups and cannot form hydrogen bonds with the hydroxyl groups on the wood flour surface, failing to improve the compatibility between the wood flour and the polystyrene resin. Consequently, the extruded board exhibits low impact and flexural strength. Furthermore, the SBS styrene-butadiene-styrene block copolymer lacks a triazole structure, failing to form a nitrogen-phosphorus flame retardant system. This results in a low limiting oxygen index for the extruded board.

[0048] In Comparative Example 3, 3-amino-1,2,4-triazole was reacted with chloromethylated SBS. The resulting modified SBS did not contain carboxyl groups and could not form hydrogen bonds with the hydroxyl groups on the surface of the wood powder. Therefore, the compatibility between the wood powder and the polystyrene resin could not be improved, resulting in low impact strength and flexural strength of the extruded board.

[0049] In Comparative Example 4, β-alanine was reacted with chloromethylated SBS to obtain a modified SBS that did not contain a triazole structure and did not form a nitrogen-phosphorus flame retardant system, resulting in a lower limiting oxygen index of the extruded board.

[0050] The present invention is not limited to the above-mentioned embodiments. Any modification, improvement, or substitution that can be conceived by those skilled in the art without departing from the essential content of the present invention shall fall within the scope of the present invention.

Claims

1. A method for preparing an impact-resistant polystyrene extruded board, characterized in that: The preparation method is as follows: (1) Add chloromethylated SBS to the reaction solvent, stir, add 5-carboxy-3-amino-1,2,4-triazole and a catalyst, stir to react, add ethanol to the solution for precipitation, filter, wash, and dry to obtain modified SBS; (2) 65-80 parts by weight of polystyrene resin, 20-35 parts by weight of wood flour, 5-15 parts by weight of modified SBS, 1.2-1.7 parts by weight of auxiliary agent, 2-3 parts by weight of nucleating agent, 2-4 parts by weight of flame retardant, and 0.4-0.6 parts by weight of antioxidant are added into a mixer and mixed, and then extruded through a twin-screw extruder, and finally extruded and foamed in a single-screw extruder to obtain an impact-resistant polystyrene extruded board.

2. The method for preparing an impact-resistant polystyrene extruded board according to claim 1, wherein: The auxiliary agent includes azodicarbonamide; and the nucleating agent includes talc.

3. The method for preparing the impact-resistant polystyrene extruded board according to claim 1, characterized in that: The flame retardant includes triphenyl phosphate; the antioxidant includes antioxidant 1010, antioxidant 1076 or antioxidant 168.

4. The method for preparing an impact-resistant polystyrene extruded board according to claim 1, wherein: The reaction solvent in (1) includes toluene or xylene.

5. The method for preparing an impact-resistant polystyrene extruded board according to claim 1, wherein: The reaction temperature in (1) is 80-110°C, and the reaction time is 24-36h.

6. The method for preparing an impact-resistant polystyrene extruded board according to claim 1, wherein: The mass ratio of chloromethylated SBS, 5-carboxyl-3-amino-1,2,4-triazole and catalyst in (1) is 100:(20-70):(26-94).

7. The method for preparing the impact-resistant polystyrene extruded board according to claim 6, characterized in that: The catalyst includes sodium carbonate or potassium carbonate.

8. The method for preparing an impact-resistant polystyrene extruded board according to claim 1, wherein: The temperature of zones 1-6 of the twin-screw extruder is 165-210° C., and the screw speed is 60-100 r / min; the temperature of zones 1-3 of the single-screw extruder is 150-180° C., and the screw speed is 50-80 r / min.

9. The method for preparing an impact-resistant polystyrene extruded board according to claim 1, wherein: The preparation method of the chloromethylated SBS comprises the following steps: adding 100 parts by weight of an SBS styrene-butadiene-styrene block copolymer and 12-30 parts by weight of tin chloride to toluene, adding dropwise 16-40 parts by weight of 1,4-bis(chloromethoxy)-butane after stirring, reacting at 15-20° C. for 4-6 hours, adding ethanol to the solution for precipitation, filtering, washing, and drying to obtain the chloromethylated SBS.

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