Novel polyphenyl ether / polystyrene foamed bead with nested structure and preparation method of novel polyphenyl ether / polystyrene foamed bead

Abstract

The invention discloses a novel polyphenyl ether / polystyrene foamed bead with a nested structure and a preparation method of the novel polyphenyl ether / polystyrene foamed bead, and belongs to the technical field of microcellular foaming of high polymer materials. The polyphenyl ether / polystyrene foamed bead is prepared from the following raw materials in percentage by mass: 40 to 85 percent of polystyrene, 5 to 40 percent of polyphenyl ether, 5 to 20 percent of polypropylene, 0.1 to 5 percent of heterogeneous nucleating agent, 0.5 to 1.2 percent of antioxidant and 0.1 to 0.3 percent of dispersing agent. According to the invention, raw materials are optimized, polytetrafluoroethylene is added to increase the adsorption effect of the material on a foaming agent, and a sea-island structure formed by polypropylene in a polyphenyl ether / polystyrene matrix is utilized to realize redesign of a foaming bubble pore structure through foaming, so that the composite material which is internally provided with a polystyrene film and has a good foaming effect is obtained. The foam holes with the polyphenyl ether / polystyrene structure are formed in the outer part, so that the foaming temperature required by the polyphenyl ether foaming bead is reduced, and the problem of high foaming temperature of the polyphenyl ether foaming bead in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of microporous foaming of polymer materials, and in particular to polyphenylene ether / polystyrene foaming beads with a novel nested structure and a preparation method thereof. Background Art

[0002] Polyphenylene oxide (PPO) is a high-strength engineering material with good temperature resistance, electrical insulation, wear resistance and excellent flame retardancy. It has a very large application market in electronic components, automotive parts, household appliances, etc. However, due to its own high processing temperature, its promotion and application in many fields is limited. The viscosity of polystyrene (PS) is much lower than that of PPO, and it has good compatibility with PPO. It is often used to adjust the viscosity of PPO to meet the foaming requirements.

[0003] Supercritical carbon dioxide autoclave foaming technology is a foaming technology that uses carbon dioxide to impregnate foaming materials at high pressure through a reactor at high temperature and then releases the pressure rapidly. It can form a uniform porous structure inside the polymer material and can produce foam materials. While greatly reducing the apparent density of the polymer, it can also take into account its good physical properties and achieve the purpose of lightweighting the material. The products produced by this technology are mostly transported in granular form. When used, they can be formed by steam molding to obtain various products. Compared with conventional injection molding and molded foaming, it has better practicality and processability.

[0004] The use of supercritical carbon dioxide autoclave foaming technology to prepare polyphenylene ether foam beads can achieve the purpose of lightweighting the material. However, in the process of obtaining the polyphenylene ether foam beads, a higher foaming temperature is usually required, making the foaming of polyphenylene ether more difficult. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a novel nested structure polyphenylene ether / polystyrene foamed beads and a preparation method thereof. The present invention optimizes the raw materials, adds polytetrafluoroethylene to increase the carbon dioxide adsorption effect of the material, and at the same time utilizes the sea-island structure formed by polypropylene in the polyphenylene ether / polystyrene matrix, and through foaming, realizes the redesign of the foaming hole structure, obtains a polypropylene film inside and a polyphenylene ether / polystyrene structure outside, reduces the foaming temperature required for the polyphenylene ether foamed beads, and solves the problem of high foaming temperature of polyphenylene ether foamed beads in the prior art.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of the present invention protects a novel nested structure of polyphenylene ether / polystyrene foam beads, the raw materials of the polyphenylene ether / polystyrene foam beads, calculated by mass percentage, include the following raw material components: 40-85% polystyrene, 5-40% polyphenylene ether, 5-20% polypropylene, 0.1-5% heterogeneous nucleating agent, 0.5-1.2% antioxidant, and 0.1-0.3% dispersant.

[0008] Preferably, the polyphenylene ether / polystyrene foam beads include the following raw material components by mass percentage: 70-85% polystyrene, 5-15% polyphenylene ether, 5-15% polypropylene, 0.1-5% heterogeneous nucleating agent, 0.5-1.2% antioxidant, and 0.1-0.3% dispersant.

[0009] Preferably, the mass ratio of the polyphenylene ether to the polypropylene is 1-2:1.

[0010] Preferably, the polyphenylene ether is obtained by drying a polyphenylene ether raw material.

[0011] Preferably, the heterogeneous nucleating agent includes at least one of polytetrafluoroethylene, zinc borate and talc; preferably, the heterogeneous nucleating agent is polytetrafluoroethylene, and the particle size of the polytetrafluoroethylene is 1-20 μm.

[0012] Preferably, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076; and the dispersant includes one or two of kaolin, butter, and montmorillonite.

[0013] The second aspect of the present invention protects a method for preparing the novel nested polyphenylene ether / polystyrene foamed beads described in the first aspect. The preparation method comprises the following steps, by mass fraction:

[0014] S1: polyphenylene ether, polystyrene, polypropylene, a heterogeneous nucleating agent and an antioxidant are mixed and stirred evenly, added into an extruder for blending and extrusion, cooled and drawn, and then granulated with a pelletizer to obtain polyphenylene ether / polystyrene pre-foamed particles;

[0015] S2: placing the polyphenylene ether / polystyrene pre-foamed microparticles in step S1 into a reactor, adding a dispersant, setting the temperature of the reactor to 140-160°C and the pressure to 1.0-4.0 MPa, and introducing a foaming agent into the reactor, heating and pressurizing for foaming, releasing the pressure, and drying to obtain polyphenylene ether / polystyrene foamed beads with a novel nested structure.

[0016] Preferably, in step S1, the stirring speed is 100-500 r / min, and the time is 10-30 min; the extrusion temperature of the extruder is 160-260° C., and the rotation speed is 10-30 r / min; and the rotation speed of the pelletizer is 500-800 r / min.

[0017] Preferably, in step S1, the polyphenylene ether / polystyrene pre-foamed microparticles have a diameter of 0.5-1.5 mm, a length of 1.8-2.5 mm, and a single particle mass of 0.5-2.0 mg.

[0018] Preferably, in step S2, the foaming agent includes at least one of CO2, N2, supercritical CO2, and supercritical N2; the heating and pressurizing time is 30-60 min; and the pressure release rate is 2-5 MPa / s.

[0019] The beneficial technical effects of the present invention are:

[0020] The present invention realizes physical foaming by synergizing polypropylene and polyphenylene ether in combination with polytetrafluoroethylene, thereby improving the problems of difficult gas storage, poor expandability, high foaming temperature, etc. during foaming. The segment rigidity of polyphenylene ether is strong, and the internal gas expands at the moment of foaming, requiring a certain gas sealing performance to ensure that the particles can expand successfully. However, when the polyphenylene ether is below 160° C., it is difficult for the rigid segment to effectively seal the gas, resulting in a large amount of internal gas escaping during foaming, and the foaming effect is very poor. The present invention introduces polypropylene, and the polypropylene exists in the pores in a nested structure as an effective nucleation point for PPO / PS foaming, thereby improving the disadvantages of difficult gas storage, poor expandability, high foaming temperature, etc. of PPO / PS, and can achieve a good gas sealing effect at a lower foaming temperature, thereby improving the foaming performance of PPO / PS.

[0021] The present invention successfully prepares PPO / PS bead foams with controllable pore size, foam density and pore density by controlling the foaming raw materials and processes. The obtained polyphenylene ether / polystyrene foamed beads have a uniform closed-cell structure, and the foaming ratio is as high as 7.6 times, and the closed-cell rate can reach 97%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram of the internal pore structure of PPO / PS bead foam prepared in Example 1 of the present invention.

[0023] Figure 2 This is a diagram showing the internal structure of the PPO / PS pre-foamed particles of Example 1 of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below in conjunction with the embodiments.

[0025] The first aspect of the present invention provides a novel nested structure of polyphenylene ether / polystyrene foam beads, wherein the raw materials for preparing the polyphenylene ether / polystyrene foam beads include the following raw material components by mass percentage: 40-85% polystyrene (PS), 5-40% polyphenylene ether (PPO), 5-20% polypropylene (PP), 0.1-5% heterogeneous nucleating agent, 0.5-1.2% antioxidant, and 0.1-0.3% dispersant.

[0026] The present invention realizes physical foaming by synergizing polypropylene and polyphenylene ether in combination with polytetrafluoroethylene, thereby improving the problems of difficult gas storage, poor expandability, high foaming temperature, etc. during foaming. The segment rigidity of polyphenylene ether is strong, and the internal gas expands at the moment of foaming, requiring a certain gas sealing performance to ensure that the particles can expand successfully. However, when the polyphenylene ether is below 160° C., it is difficult for the rigid segment to effectively seal the gas, resulting in a large amount of internal gas escaping during foaming, and the foaming effect is very poor. The present invention introduces polypropylene, and the polypropylene exists in the pores in a nested structure as an effective nucleation point for PPO / PS foaming, thereby improving the disadvantages of difficult gas storage, poor expandability, high foaming temperature, etc. of PPO / PS, and can achieve a good gas sealing effect at a lower foaming temperature, thereby improving the foaming performance of PPO / PS.

[0027] In some embodiments, the polyphenylene ether / polystyrene foam beads include the following raw material components by mass percentage: 70-85% polystyrene, 5-15% polyphenylene ether, 5-15% polypropylene, 0.1-5% heterogeneous nucleating agent, 0.5-1.2% antioxidant, and 0.1-0.3% dispersant.

[0028] In some embodiments, the mass ratio of the polyphenylene ether to the polypropylene is 1-2: 1. The present invention regulates the formation of the pore structure by controlling the relative amounts of polyphenylene ether and polypropylene. When there is too much polyphenylene ether and too little polypropylene, the foaming ratio is low and the pore size is small. When there is too little polyphenylene ether and too much polypropylene, the foam will be over-expanded, and a large number of pores will merge and the pores will rupture.

[0029] The polyphenylene ether is obtained by drying a polyphenylene ether raw material.

[0030] In some embodiments, the polyphenylene ether is pure polyphenylene ether powder.

[0031] In some embodiments, the heterogeneous nucleating agent includes at least one of polytetrafluoroethylene, zinc borate, and talc; preferably, the heterogeneous nucleating agent is polytetrafluoroethylene.

[0032] In some embodiments, the particle size of the polytetrafluoroethylene is 1-20 μm, including but not limited to 1 μm, 5 μm, 10 μm, 15 μm, and 20 μm.

[0033] It is understandable that the heterogeneous nucleating agent PTFE used in the present invention has a good affinity for carbon dioxide and can adsorb more gas under the same conditions, which is conducive to the formation of pores. Although the drying step before processing has little effect on the overall foaming, small bubbles are more likely to appear inside the raw materials that are not dried during the processing.

[0034] In some embodiments, the antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076; the dispersant includes one or two of kaolin, butter, and montmorillonite.

[0035] The second aspect of the present invention protects a method for preparing the novel nested polyphenylene ether / polystyrene foamed beads described in the first aspect, the preparation method comprising the following steps:

[0036] S1: According to the mass fraction, polyphenylene ether, polystyrene polypropylene, heterogeneous nucleating agent and antioxidant are mixed, stirred evenly, added into an extruder for blending and extrusion, cooled and drawn, and granulated with a pelletizer to obtain polyphenylene ether / polystyrene pre-foamed particles;

[0037] S2: placing the polyphenylene ether / polystyrene pre-foamed microparticles in step S1 into a reactor, adding a dispersant, setting the temperature of the reactor to 140-160°C, including but not limited to 140°C, 150°C, and 160°C, and the pressure to 1.0-4.0MPa, including but not limited to 1.0MPa, 2MPa, 3MPa, and 4MPa, and introducing a foaming agent into the reactor, heating and pressurizing for foaming, releasing the pressure, and drying to obtain polyphenylene ether / polystyrene foamed beads with a novel nested structure.

[0038] In some embodiments, in step S1, the stirring speed is 100-500r / min, including but not limited to 100r / min, 200r / min, 300r / min, 400r / min, 500r / min, and the time is 10-30min, including but not limited to 10min, 15min, 20min, 25min, 30min; the extrusion temperature of the extruder is 160-260℃, including but not limited to 160℃, 180℃, 200℃, 220℃, 240℃, 260℃, and the rotation speed is 10-30r / min, including but not limited to 10r / min, 15r / min, 20r / min, 25r / min, 30r / min; the rotation speed of the pelletizer is 500-800r / min, including but not limited to 500r / min, 600r / min, 700r / min, 800r / min.

[0039] In some embodiments, in step S1, the diameter of the polyphenylene ether / polystyrene pre-foamed particles is 0.5-1.5 mm, including but not limited to 0.5 mm, 1.0 mm, and 1.5 mm, the length is 1.8-2.5 mm, including but not limited to 1.8 mm, 2.0 mm, 2.2 mm, and 2.5 mm, and the mass of a single particle is 0.5-2.0 mg, including but not limited to 0.5 mg, 1.0 mg, 1.5 mg, and 2.0 mg.

[0040] In some embodiments, in step S2, the foaming agent includes at least one of CO2, N2, supercritical CO2, and supercritical N2; the heating and pressurizing time is 30-60 min, including but not limited to 30 min, 40 min, 50 min, and 60 min; the pressure release rate is 2-5 MPa / s, including but not limited to 2 MPa / s, 3 MPa / s, 4 MPa / s, and 5 MPa / s.

[0041] It is understandable that the present invention reduces the foaming temperature, and materials with good foaming properties can be obtained at lower foaming temperatures. Moreover, in the scheme of the present invention, when the foaming temperature exceeds the specified range, a large number of pores may rupture, because the glass transition temperature of PP is increased, and if the strength of PPO is insufficient, it may not be able to be formed.

[0042] The present invention successfully prepares PPO / PS bead foams with controllable pore size, foam density and pore density by controlling the foaming raw materials and processes. The obtained polyphenylene ether / polystyrene foamed beads have a uniform closed-cell structure, and the foaming ratio is up to 7.6 times, and the foaming density is 0.132g / cm 3 The average cell size is about 36μm, and the closed cell rate reaches 97%.

[0043] The present invention will be further described below by way of examples and the like.

[0044] Example 1

[0045] A PPO / PS bead foam, wherein the raw materials for preparing the bead foam include the following components by mass percentage: PPO 10%, PS 83.4%, PP 5%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. Among them, PS is PG-33(2) of Zhenjiang Chimei Chemical Co., Ltd.; PPO is LXN035 of Nantong Xingchen Synthetic Materials Co., Ltd.; PP is FL7540L of Singapore Polypropylene Co., Ltd. (tpc); the heterogeneous nucleating agent is PTFE, provided by Nanjing Tianshi New Materials Co., Ltd., and its particle size is 5 μm. The antioxidant is antioxidant 1010. The dispersant is a mixture of kaolin and butter, wherein the mass ratio of kaolin to butter is 1:1, and the foaming agent is CO2, which has a purity of 99.9% and is provided by Linde CO2 Co., Ltd.

[0046] The preparation of the above-mentioned PPO / PS bead foam comprises the following steps:

[0047] (1) PPO, PS, heterogeneous nucleating agent PTFE, PP, and antioxidant 1010 were added into a high-speed mixer according to mass percentage, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-200-220-240-240-230-210° C., and the rotation speed was 20 r / min; after underwater cooling and drawing, PPO / PS pre-foamed microparticles were prepared in a pelletizer, wherein the rotation speed of the pelletizer was 500 r / min.

[0048] (2) Add the prepared PPO / PS pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 145°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0049] The microstructure of the PPO / PS pre-expanded particles prepared in step 1 of this embodiment was photographed using a scanning electron microscope. Figure 2 As shown by Figure 2 The sea-island structure formed by polypropylene in the polyphenylene ether / polystyrene matrix can be seen.

[0050] The internal cell structure of the PPO / PS bead foam prepared in step (2) of Example 1 was photographed using a scanning electron microscope. Figure 1 As shown, it can be seen that the foamed particles prepared in the example have cells with a polypropylene film inside and a polyphenylene ether / polystyrene structure outside.

[0051] Example 2

[0052] A PPO / PS bead foam, wherein the raw materials of the bead foam include the following components by mass percentage: PPO 15%, PS 74.4%, PP 9%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. The manufacturer model of each raw material is the same as that of Example 1.

[0053] The preparation of the PPO / PS bead foam comprises the following steps:

[0054] (1) According to the mass percentage, PPO, PS, heterogeneous nucleating agent PTFE, PP, and antioxidant 1010 were added into a high-speed mixer, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-210-230-240-240-230-210° C., and the speed was 20 r / min; after underwater cooling and drawing, PPO / PS pre-foamed microparticles were prepared in a pelletizer, wherein the speed of the pelletizer was 500 r / min;

[0055] (2) Add the prepared PPO / PS pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 145°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0056] Example 3

[0057] A PPO / PS bead foam, wherein the raw materials of the bead foam include the following components by mass percentage: PPO 13%, PS 73.4%, PP 12%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. The manufacturer model of each raw material is the same as that of Example 1.

[0058] The preparation of the PPO / PS bead foam comprises the following steps:

[0059] (1) According to the mass percentage, PPO, PS, heterogeneous nucleating agent PTFE, PP, and antioxidant 1010 are added to a high-speed mixer, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added to a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder is 190-210-220-240-240-230-210° C., and the speed is 20 r / min; after underwater cooling and drawing, PPO / PS pre-foamed microparticles are prepared in a pelletizer, wherein the speed of the pelletizer is 500 r / min;

[0060] (2) Add the prepared PPO / PS pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 145°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0061] Example 4

[0062] A PPO / PS bead foam, wherein the raw materials of the bead foam include the following components by mass percentage: PPO 15%, PS 68.4%, PP 15%, heterogeneous nucleating agent 0.5%, antioxidant 1010 1.2%, and dispersant 0.3%. The manufacturer model of each raw material is the same as that of Example 1.

[0063] The preparation of the PPO / PS bead foam comprises the following steps:

[0064] (1) According to the mass percentage, PPO, PS, heterogeneous nucleating agent PTFE, PP, and antioxidant 1010 were added into a high-speed mixer, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-210-230-240-240-230-210° C., and the speed was 20 r / min; after underwater cooling and drawing, PPO / PS pre-foamed microparticles were prepared in a pelletizer, wherein the speed of the pelletizer was 500 r / min;

[0065] (2) Add the prepared PPO / PS pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 145°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0066] Example 5

[0067] A PPO / PS bead foam, wherein the raw materials for preparing the bead foam include the following components by mass percentage: PPO 10%, PS 83.4%, PP 5%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. Among them, PS is PG-33(2) of Zhenjiang Chimei Chemical Co., Ltd.; PPO is LXN035 of Nantong Xingchen Synthetic Materials Co., Ltd.; PP is FL7540L of Singapore Polypropylene Co., Ltd. (tpc); the heterogeneous nucleating agent is PTFE, provided by Nanjing Tianshi New Materials Co., Ltd., and its particle size is 5μm. The antioxidant is antioxidant 168. The dispersant is a mixture of kaolin and butter, wherein the mass ratio of kaolin to butter is 1:1, and the foaming agent is CO2, with a purity of 99.9%, provided by Linde CO2 Co., Ltd.

[0068] The preparation of the above-mentioned PPO / PS bead foam comprises the following steps:

[0069] (1) PPO, PS, heterogeneous nucleating agent PTFE, PP, and antioxidant 1010 were added into a high-speed mixer according to mass percentage, stirred at a speed of 100 r / min for 30 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-200-220-240-240-230-210° C., and the rotation speed was 10 r / min; after underwater cooling and drawing, PPO / PS pre-foamed microparticles were prepared in a pelletizer, wherein the rotation speed of the pelletizer was 700 r / min.

[0070] (2) Add the prepared PPO / PS pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 140°C and the pressure to 1.0 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 30 minutes, release the pressure at a rate of 3 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0071] Example 6

[0072] A PPO / PS bead foam, wherein the raw materials for preparing the bead foam include the following components by mass percentage: PPO 10%, PS 83.4%, PP 5%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. Among them, PS is PG-33(2) of Zhenjiang Chimei Chemical Co., Ltd.; PPO is LXN035 of Nantong Xingchen Synthetic Materials Co., Ltd.; PP is FL7540L of Singapore Polypropylene Co., Ltd. (tpc); the heterogeneous nucleating agent is PTFE, provided by Nanjing Tianshi New Materials Co., Ltd., and its particle size is 5μm. The antioxidant is antioxidant 1076. The dispersant is a mixture of kaolin and butter, wherein the mass ratio of kaolin to butter is 1:1, and the foaming agent is CO2, with a purity of 99.9%, provided by Linde CO2 Co., Ltd.

[0073] The preparation of the above-mentioned PPO / PS bead foam comprises the following steps:

[0074] (1) PPO, PS, heterogeneous nucleating agent PTFE, PP, and antioxidant 1010 were added into a high-speed mixer according to mass percentage, stirred at a speed of 300 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-200-220-240-240-230-210° C., and the rotation speed was 30 r / min; after underwater cooling and drawing, PPO / PS pre-foamed microparticles were prepared in a pelletizer, wherein the rotation speed of the pelletizer was 800 r / min.

[0075] (2) Add the prepared PPO / PS pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 160°C and the pressure to 3 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 60 minutes, release the pressure at a rate of 5 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0076] Comparative Example 1

[0077] A PPO / PS bead foam, wherein the raw materials of the bead foam include the following components by mass percentage: PPO 10%, PS 88.4%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. The manufacturer model of each raw material is the same as that of Example 1. Compared with Example 1, Comparative Example 1 does not add PP.

[0078] The preparation of the PPO / PS bead foam comprises the following steps:

[0079] (1) PPO, PS, heterogeneous nucleating agent PTFE, and antioxidant 1010 were added into a high-speed mixer according to mass percentage, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-200-220-240-240-230-210° C., and the speed was 20 r / min; PPO / PS pre-foamed microparticles were prepared by underwater cooling and drawing, wherein the speed of the pelletizer was 500 r / min;

[0080] (2) Add the prepared PPO / PS / PP pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 145°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0081] Comparative Example 2

[0082] A PPO / PS bead foam board, wherein the raw materials of the bead foam board include the following components by mass percentage: PPO 10%, PS 88.4%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. The manufacturer model of each raw material is the same as that of Example 1. The foaming temperature of Comparative Example 1 is different from that of Comparative Example 2.

[0083] The preparation of the PPO / PS bead foam board comprises the following steps:

[0084] (1) PPO, PS, heterogeneous nucleating agent PTFE, and antioxidant 1010 were added into a high-speed mixer according to mass percentage, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-200-220-240-240-230-210° C., and the speed was 20 r / min; PPO / PS pre-foamed microparticles were prepared by underwater cooling and drawing, wherein the speed of the pelletizer was 500 r / min;

[0085] (2) Add the prepared PPO / PS / PP pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 150°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0086] Comparative Example 3

[0087] A PPO / PS bead foam, wherein the raw materials of the bead foam include the following components by mass percentage: PPO 15%, PS 74.5%, PP 9%, antioxidant 10101.2%, and dispersant 0.3%. The manufacturer model of each raw material is the same as that of Example 1. The amount of heterogeneous nucleating agent PTFE used in Comparative Example 3 is different from that in Example 2.

[0088] The preparation of the PPO / PS bead foam comprises the following steps:

[0089] (1) PPO, PS, PP and antioxidant 1010 were added into a high-speed mixer according to mass percentage, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-200-220-240-240-230-210° C., and the speed was 20 r / min; PPO / PS pre-foamed microparticles were prepared by a pelletizer after underwater cooling and drawing, wherein the speed of the pelletizer was 500 r / min;

[0090] (2) Add the prepared PPO / PS / PP pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 145°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0091] Comparative Example 4

[0092] A PPO / PS bead foam, wherein the raw materials of the bead foam include the following components by mass percentage: PPO 15%, PS 74.4%, PP 9%, heterogeneous nucleating agent 0.1%, antioxidant 1010 1.2%, and dispersant 0.3%. The manufacturer model of each raw material is the same as that of Example 1. Comparative Example 4 Compared with Example 2, the polyphenylene ether raw material is not dried at 90°C.

[0093] The preparation of the PPO / PS bead foam comprises the following steps:

[0094] (1) According to the mass percentage, PPO, PS, heterogeneous nucleating agent PTFE, PP, and antioxidant 1010 were added into a high-speed mixer, stirred at a speed of 500 r / min for 20 min, and mixed evenly, and then added into a twin-screw extruder for melt blending, wherein the extrusion temperature range of the twin-screw extruder was 190-210-230-240-240-230-210° C., and the speed was 20 r / min; after underwater cooling and drawing, PPO / PS pre-foamed microparticles were prepared in a pelletizer, wherein the speed of the pelletizer was 500 r / min;

[0095] (2) Add the prepared PPO / PS pre-expanded particles into a reactor, and add kaolin and butter. Set the temperature of the reactor to 145°C and the pressure to 4 MPa. Allow CO2 to enter the reactor through the air inlet on the reactor for heating and pressurization. After the PPO / PS / PP particles are saturated with CO2 for 45 minutes, release the pressure at a rate of 2 MPa / s to normal atmospheric pressure, and then dry to obtain PPO / PS bead foam.

[0096] Test example:

[0097] The PPO / PS foamed beads prepared in Examples 1-4 and Comparative Examples 1-4 were examined by scanning electron microscopy, and the average cell size was calculated using ImagePro software. The closed cell ratio was measured by a true density meter according to GB / T10799-2008 standard, and the foam density and expansion ratio of the PPO / PS foamed beads were measured by the drainage method. The results are shown in Table 1.

[0098] Table 1 Comparison of the properties of the bead foams prepared in Examples 1-2 and Comparative Examples 1-4 of the present application

[0099]

[0100]

[0101] As can be seen from Table 1, using CO2 as a foaming agent, PTFE as a nucleating agent, and PP as a cell improver, PPO / PS foam particles with uniform cell size and high foaming ratio can be prepared at a lower foaming temperature; at the same foaming temperature, compared with the foaming material without PP, the foaming ratio is significantly improved after adding PP, which is due to the strong flexibility of the PP molecular chain and the good sealing effect on the gas. At the same time, PS and PPO are relatively rigid and can be effectively used as the supporting structure of PP. The nested structure formed by the cooperation of the two parties will achieve an excellent foaming effect. At the same time, different amounts of PP added can effectively control the cell size, which is convenient for making foam particles with different cell sizes. It can be seen from Comparative Example 3 that due to the good affinity of the heterogeneous nucleating agent PTFE to carbon dioxide, more gas can be adsorbed under the same conditions, which is more conducive to the formation of cells. Comparative Example 4 did not dry the polyphenylene ether raw material, which had little effect on the overall foaming situation, but small bubbles were more likely to appear inside the raw material that was not dried during the processing, resulting in problems such as broken wires that were very likely to occur during the wire drawing process.

[0102] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A novel nested structure of polyphenylene ether / polystyrene foam beads, characterized in that: The polyphenylene ether / polystyrene foaming beads include the following raw material components by mass percentage: 40-85% polystyrene, 5-40% polyphenylene ether, 5-20% polypropylene, 0.1-5% heterogeneous nucleating agent, 0.5-1.2% antioxidant, and 0.1-0.3% dispersant.

2. The polyphenylene ether / polystyrene foamed beads according to claim 1, characterized in that: The polyphenylene ether / polystyrene foaming beads include the following raw material components by mass percentage: 70-85% polystyrene, 5-15% polyphenylene ether, 5-15% polypropylene, 0.1-5% heterogeneous nucleating agent, 0.5-1.2% antioxidant, and 0.1-0.3% dispersant.

3. The polyphenylene ether / polystyrene foamed beads according to claim 1, characterized in that: The mass ratio of the polyphenylene ether to the polypropylene is 1-2:

1.

4. The polyphenylene ether / polystyrene foamed beads according to claim 1, characterized in that: The polyphenylene ether is obtained by drying a polyphenylene ether raw material.

5. The polyphenylene ether / polystyrene foamed beads according to claim 1, characterized in that: The heterogeneous nucleating agent includes at least one of polytetrafluoroethylene, zinc borate and talc; Preferably, the heterogeneous nucleating agent is polytetrafluoroethylene, and the particle size of the polytetrafluoroethylene is 1-20 μm.

6. The polyphenylene ether / polystyrene foamed beads according to claim 1, characterized in that: The antioxidant includes one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076; The dispersant includes one or two of kaolin, butter and montmorillonite.

7. A method for preparing the novel nested polyphenylene ether / polystyrene foamed beads according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps, by mass fraction: S1: polyphenylene ether, polystyrene, polypropylene, a heterogeneous nucleating agent and an antioxidant are mixed and stirred evenly, added into an extruder for blending and extrusion, cooled and drawn, and then granulated with a pelletizer to obtain polyphenylene ether / polystyrene pre-foamed particles; S2: placing the polyphenylene ether / polystyrene pre-foamed microparticles in step S1 into a reactor, adding a dispersant, setting the temperature of the reactor to 140-160°C and the pressure to 1.0-4.0 MPa, and introducing a foaming agent into the reactor, heating and pressurizing for foaming, releasing the pressure, and drying to obtain polyphenylene ether / polystyrene foamed beads with a novel nested structure.

8. The preparation method according to claim 7, characterized in that: In step S1, the stirring speed is 100-500 r / min, and the time is 10-30 min; the extrusion temperature of the extruder is 160-260° C., and the rotation speed is 10-30 r / min; and the rotation speed of the pelletizer is 500-800 r / min.

9. The preparation method according to claim 7, characterized in that: In step S1, the polyphenylene ether / polystyrene pre-foamed microparticles have a diameter of 0.5-1.5 mm, a length of 1.8-2.5 mm, and a single particle mass of 0.5-2.0 mg.

10. The preparation method according to claim 7, characterized in that: In step S2, the foaming agent includes at least one of CO2, N2, supercritical CO2, and supercritical N2; The heating and pressurizing time is 30-60 minutes; the pressure relief rate is 2-5 MPa / s.

Images