Preparation method of impact-resistant polystyrene extruded sheet

Abstract

The invention relates to the technical field of polystyrene, and discloses a preparation method of an impact-resistant polystyrene extruded sheet, which comprises the following steps: mixing 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 an auxiliary agent, 2-4 parts by weight of a flame retardant and the like, extruding, and carrying out foam molding to obtain the impact-resistant polystyrene extruded sheet. The side chain of the modified SBS contains carboxyl which can form hydrogen bond interaction with hydroxyl on the surface of the wood flour, so that the compatibility between the wood flour and the polystyrene resin is improved, the mechanical property of the extruded sheet is improved, and the extruded sheet shows higher impact strength and bending strength. A triazole structure is introduced into a modified SBS side chain and forms a nitrogen-phosphorus flame retardant with triphenyl phosphate, so that the limit oxygen index and flame retardance of the extruded sheet are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polystyrene, and specifically to a preparation method of an impact-resistant polystyrene extrusion board. Background Art

[0002] Polystyrene extrusion boards are light in weight, low in water absorption, good in heat insulation performance, and excellent in sound insulation effect, and are widely used in building materials, petrochemical and other fields. Traditional polystyrene boards have problems such as low impact resistance and easy combustion. Blending polystyrene with wood flour can obtain a wood-plastic material with excellent flame retardancy and high mechanical strength. In order to improve the compatibility between wood flour and polystyrene, it is usually necessary to modify the wood flour with silane coupling agents, maleic anhydride, etc., or add compatibilizers such as maleic anhydride-grafted polystyrene.

[0003] Adding an elastomer material to the polystyrene board can improve its toughness, impact strength and other properties. SBS styrene-butadiene-styrene block copolymer is an elastomer material with excellent properties and is widely used. Reacting or grafting SBS with chloromethylating reagents, maleic anhydride, acrylate and other substances can obtain a functional SBS material. Chinese Patent CN109294087B discloses a modified polystyrene material and its preparation method, using polystyrene, star-shaped SBS, core-shell toughening agent and other raw materials. The prepared modified polystyrene has advantages such as good impact strength and good melt fluidity, but this modified polystyrene does not have good flame retardancy. Summary of the Invention

[0004] Technical problem to be solved: The present invention provides a preparation method of an impact-resistant polystyrene extrusion board, which solves the problems of easy combustion and low impact strength of the polystyrene extrusion board.

[0005] Technical solution: A preparation method of an impact-resistant polystyrene extrusion board: (1) Add chloromethylated SBS to the reaction solvent, stir, then add 5-carboxy-3-amino-1,2,4-triazole and a catalyst, stir and react, add ethanol to the solution for precipitation, filter, wash with water and ethanol, and dry to obtain modified SBS.

[0006] (2) Add 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 an auxiliary agent, 2-3 parts by weight of a nucleating agent, 2-4 parts by weight of a flame retardant, and 0.4-0.6 parts by weight of an antioxidant to a mixer for mixing, then extrude through a twin-screw extruder, and finally extrude and foam-mold in a single-screw extruder to obtain an impact-resistant polystyrene extrusion board.

[0007] Further, the auxiliary agent includes azodicarbonamide.

[0008] Furthermore, the nucleating agent includes talcum powder.

[0009] Furthermore, the flame retardant includes triphenyl phosphate.

[0010] Furthermore, the antioxidant includes antioxidant 1010, antioxidant 1076 or antioxidant 168.

[0011] Furthermore, the reaction solvent in (1) includes toluene or xylene.

[0012] Furthermore, the reaction temperature in (1) is 80 - 110 °C, and the reaction time is 24 - 36 h.

[0013] Furthermore, the mass ratio of chloromethylated SBS, 5 - carboxy - 3 - amino - 1,2,4 - triazole, and the catalyst in (1) is 100:(20 - 70):(26 - 94).

[0014] Furthermore, the catalyst in (1) includes sodium carbonate or potassium carbonate.

[0015] Furthermore, the temperature of the 1 - 6 zones of the twin - screw extruder in (2) is 165 - 210 °C, and the screw speed is 60 - 100 r / min. The temperature of the 1 - 3 zones of the single - screw extruder is 150 - 180 °C, and the screw speed is 50 - 80 r / min.

[0016] Furthermore, the preparation method of chloromethylated SBS is as follows: Add 100 parts by weight of SBS (styrene - butadiene - styrene block copolymer) to toluene, 12 - 30 parts by weight of tin chloride, stir and then dropwise add 16 - 40 parts by weight of 1,4 - bis(chloromethoxy) - butane, react at 15 - 20 °C for 4 - 6 h, add ethanol to the solution for precipitation, filter, wash with water, and dry to obtain chloromethylated SBS.

[0017] Beneficial technical effects: In the present invention, a substitution reaction is carried out between the chloromethyl group of chloromethylated SBS and the amino group of 5 - carboxy - 3 - amino - 1,2,4 - triazole to obtain modified SBS, and then it is subjected to extrusion foaming with polystyrene resin, wood powder, triphenyl phosphate flame retardant, additives, etc. to obtain an impact - resistant polystyrene extrusion board. The side chain of this modified SBS contains carboxyl groups, which can form hydrogen - bond interactions with the hydroxyl groups on the surface of wood powder, so that the modified SBS modifies and coats the surface of wood powder. Since the SBS (styrene - butadiene - styrene block copolymer) has good compatibility with polystyrene resin, the compatibility between wood powder and polystyrene resin is improved, the interfacial strength between the two is enhanced, which is beneficial to improving the mechanical properties of the extrusion board, showing higher impact strength and bending strength.

[0018] The triazole structure introduced into the side chain of the modified SBS of the present invention forms a nitrogen-phosphorus flame retardant with triphenyl phosphate. When burning, it generates gases such as nitrogen, promotes the formation of an expanded carbon layer in the extruded board, and improves the limiting oxygen index and flame retardant performance of the extruded board. Description of the Drawings

[0019] Figure 1 It is the preparation reaction formula of modified SBS.

[0020] Figure 2 It is the infrared spectrum of modified SBS. Detailed Embodiments

[0021] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0022] Example 1: (1) Add 200 g of SBS styrene-butadiene-styrene block copolymer and 24 g of stannous chloride to 10 L of toluene. After stirring, add 32 g of 1,4-bis(chloromethoxy)butane dropwise, and react at 20 °C for 4 h. Add ethanol to the solution for precipitation, filter, wash with water, and dry to obtain chloromethylated SBS.

[0023] (2) Add 300 g of chloromethylated SBS to 10 L of toluene, heat to 100 °C, add 60 g of 5-carboxy-3-amino-1,2,4-triazole and 78 g of catalyst potassium carbonate after stirring, 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 In 3424 cm -1 and 1721 cm -1 are the absorption peaks of -OH in the carboxyl group and -C=O- in the carbonyl group. 1450 cm -1 is the absorption peak of the -C=N- bond in triazole.

[0024] (3) Add 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 auxiliaries azodicarbonamide, 300 g of nucleating agent talc powder, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 to a mixer for mixing, and then extrude through a twin-screw extruder. The temperatures of zones 1-6 are 165 °C, 190 °C, 200 °C, 210 °C, 210 °C, and 205 °C, and the screw speed is 100 r / min; finally, foam molding is carried out in a single-screw extruder. The temperatures of zones 1-3 are 150 °C, 180 °C, and 170 °C, and the screw speed is 80 r / min to obtain an impact-resistant polystyrene extruded board.

[0025] Example 2: (1) Add 200 g of styrene-butadiene-styrene block copolymer (SBS), 40 g of tin chloride to 12 L of toluene. After stirring, add 55 g of 1,4-bis(chloromethoxy)butane dropwise, and react at 20 °C for 5 h. Add ethanol to the solution for precipitation, filter, wash with water, and dry to obtain chloromethylated SBS.

[0026] (2) Add 300 g of chloromethylated SBS to 11 L of xylene, heat to 80 °C, add 130 g of 5-carboxy-3-amino-1,2,4-triazole and 170 g of potassium carbonate catalyst after stirring, 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.

[0027] (3) Add 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 azodicarbonamide as an additive, 260 g of talc as a nucleating agent, 0.3 kg of triphenyl phosphate as a flame retardant, and 40 g of antioxidant 168 to a mixer for mixing, and then extrude through a twin-screw extruder. The temperatures in zones 1-6 are 165 °C, 190 °C, 200 °C, 210 °C, 210 °C, and 205 °C, and the screw speed is 60 r / min; finally, foam molding is carried out in a single-screw extruder. The temperatures in zones 1-3 are 150 °C, 180 °C, and 170 °C, and the screw speed is 80 r / min to obtain an impact-resistant polystyrene extrusion sheet.

[0028] Example 3: (1) Add 200 g of styrene-butadiene-styrene block copolymer (SBS), 60 g of tin chloride to 12 L of toluene. After stirring, add 80 g of 1,4-bis(chloromethoxy)butane dropwise, and react at 15 °C for 6 h. Add ethanol to the solution for precipitation, filter, wash with water, and dry to obtain chloromethylated SBS.

[0029] (2) Add 300 g of chloromethylated SBS to 13 L of toluene, heat to 110 °C, add 210 g of 5-carboxy-3-amino-1,2,4-triazole and 282 g of sodium carbonate catalyst after stirring, 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.

[0030] (3) Add 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 azodicarbonamide as an additive, 200 g of talc as a nucleating agent, 0.2 kg of triphenyl phosphate as a flame retardant, and 40 g of antioxidant 1010 into a mixer for mixing, and then extrude through a twin-screw extruder. The temperatures of zones 1-6 are 165 °C, 190 °C, 200 °C, 210 °C, 210 °C, and 205 °C, and the screw speed is 100 r / min; finally, foam molding is carried out in a single-screw extruder. The temperatures of zones 1-3 are 150 °C, 180 °C, and 170 °C, and the screw speed is 50 r / min to obtain an impact-resistant polystyrene extrusion board.

[0031] Comparative Example 1. The difference between this comparative example and Example 1 is that SBS styrene-butadiene-styrene block copolymer is used instead of modified SBS.

[0032] (1) Add 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 azodicarbonamide as an additive, 300 g of talc as a nucleating agent, 0.4 kg of triphenyl phosphate as a flame retardant, and 46 g of antioxidant 1076 into a mixer for mixing, and then extrude through a twin-screw extruder. The temperatures of zones 1-6 are 165 °C, 190 °C, 200 °C, 210 °C, 210 °C, and 205 °C, and the screw speed is 100 r / min; finally, foam molding is carried out in a single-screw extruder. The temperatures of zones 1-3 are 150 °C, 180 °C, and 170 °C, and the screw speed is 80 r / min to obtain an impact-resistant polystyrene extrusion board.

[0033] Comparative Example 2. The difference between this comparative example and Example 1 is that chloromethylated SBS is used instead of modified SBS.

[0034] (1) Add 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 azodicarbonamide as an additive, 300 g of talc as a nucleating agent, 0.4 kg of triphenyl phosphate as a flame retardant, and 46 g of antioxidant 1076 into a mixer for mixing, and then extrude through a twin-screw extruder. The temperatures of zones 1-6 are 165 °C, 190 °C, 200 °C, 210 °C, 210 °C, and 205 °C, and the screw speed is 100 r / min; finally, foam molding is carried out in a single-screw extruder. The temperatures of zones 1-3 are 150 °C, 180 °C, and 170 °C, and the screw speed is 80 r / min to obtain an impact-resistant polystyrene extrusion board.

[0035] Comparative Example 3. The difference between this comparative example and Example 1 is that 3-amino-1,2,4-triazole is used instead of 5-carboxy-3-amino-1,2,4-triazole.

[0036] (1) Add 300 g of chloromethylated SBS to 10 L of toluene, heat to 100 °C, stir and then add 60 g of 3-amino-1,2,4-triazole (CAS No. 61-82-5) and 78 g of catalyst potassium carbonate. Stir and react for 24 h. Add ethanol to the solution for precipitation, filter and wash with water and ethanol, and dry to obtain modified SBS.

[0037] (2) Add 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 azodicarbonamide, 300 g of nucleating agent talc powder, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 into a mixer for mixing, and then extrude through a twin-screw extruder. The temperatures of zones 1-6 are 165 °C, 190 °C, 200 °C, 210 °C, 210 °C, and 205 °C, and the screw speed is 100 r / min; finally, foam molding is carried out in a single-screw extruder. The temperatures of zones 1-3 are 150 °C, 180 °C, and 170 °C, and the screw speed is 80 r / min to obtain an impact-resistant polystyrene extrusion sheet.

[0038] Comparative Example 4. The difference between this comparative example and Example 1 is that β-alanine is used instead of 5-carboxy-3-amino-1,2,4-triazole.

[0039] (1) Add 300 g of chloromethylated SBS to 10 L of toluene, heat to 100 °C, stir and then add 60 g of β-alanine (CAS No. 107-95-9) and 78 g of catalyst potassium carbonate. Stir and react for 24 h. Add ethanol to the solution for precipitation, filter and wash with water and ethanol, and dry to obtain modified SBS.

[0040] (2) Add 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 azodicarbonamide, 300 g of nucleating agent talc powder, 0.4 kg of flame retardant triphenyl phosphate, and 46 g of antioxidant 1076 into a mixer for mixing, and then extrude through a twin-screw extruder. The temperatures of zones 1-6 are 165 °C, 190 °C, 200 °C, 210 °C, 210 °C, and 205 °C, and the screw speed is 100 r / min; finally, foam molding is carried out in a single-screw extruder. The temperatures of zones 1-3 are 150 °C, 180 °C, and 170 °C, and the screw speed is 80 r / min to obtain an impact-resistant polystyrene extrusion sheet.

[0041] The notched Izod impact strength is tested according to the standard of GB / T 1043.1-2008. The flexural strength is tested according to the standard of GB / T 9341-2008. The flame retardant performance is tested according to the standard of GB / T 2406.2-2009.

[0042] Table 1 Performance test of polystyrene extruded board

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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 preparation method of an impact-resistant polystyrene extrusion board, characterized in that, The preparation method is as follows: (1) Add chloromethylated SBS to the reaction solvent, stir, then add 5-carboxy-3-amino-1,2,4-triazole and a catalyst, stir and react, add ethanol to the solution for precipitation, filter, wash, and dry to obtain modified SBS; (2) Add 65-80 parts by weight of polystyrene resin, 20-35 parts by weight of wood powder, 5-15 parts by weight of modified SBS, 1.2-1.7 parts by weight of an auxiliary agent, 2-3 parts by weight of a nucleating agent, 2-4 parts by weight of a flame retardant, and 0.4-0.6 parts by weight of an antioxidant to a mixer for mixing, then extrude through a twin-screw extruder, and finally foam and mold in a single-screw extruder to obtain an impact-resistant polystyrene extrusion board.

2. The preparation method of the impact-resistant polystyrene extruded sheet according to claim 1, characterized in that, The auxiliary agent includes azodicarbonamide; the nucleating agent includes talcum powder.

3. The preparation method of the impact-resistant polystyrene extrusion 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 preparation method of the impact-resistant polystyrene extruded sheet according to claim 1, characterized in that, The reaction solvent in (1) includes toluene or xylene.

5. The preparation method of the impact-resistant polystyrene extrusion board according to claim 1, characterized in that, The reaction temperature in (1) is 80-110 °C, and the reaction time is 24-36 h.

6. The preparation method of the impact-resistant polystyrene extruded sheet according to claim 1, characterized in that, The mass ratio of chloromethylated SBS, 5-carboxy-3-amino-1,2,4-triazole, and the catalyst in (1) is 100:(20-70):(26-94).

7. The preparation method of the impact-resistant polystyrene extruded sheet according to claim 6, characterized in that, The catalyst includes sodium carbonate or potassium carbonate.

8. The preparation method of the impact-resistant polystyrene extruded sheet according to claim 1, characterized in that, The temperature of the 1-6 zones of the twin-screw extruder of the screw extruder is 165-210 °C, and the screw speed is 60-100 r / min; the temperature of the 1-3 zones of the single-screw extruder is 150-180 °C, and the screw speed is 50-80 r / min.

9. The preparation method of the impact-resistant polystyrene extruded sheet according to claim 1, characterized in that, The preparation method of the chloromethylated SBS is: add 100 parts by weight of SBS styrene-butadiene-styrene block copolymer to toluene, 12-30 parts by weight of tin chloride, stir and then dropwise add 16-40 parts by weight of 1,4-bis(chloromethoxy)butane, react at 15-20 °C for 4-6 h, add ethanol to the solution for precipitation, filter, wash, and dry to obtain chloromethylated SBS.

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