CN116178907A - Flame-retardant polyester expanded beads, and preparation method and application thereof - Google Patents

Abstract

The invention discloses flame-retardant polyester foam beads and its preparation method and application. The raw materials for forming the flame-retardant polyester foam beads include: polyester, chain extender, nucleating agent, flame retardant , antioxidants, surfactants and physical blowing agents. The flame-retardant polyester foamed beads have excellent characteristics such as environmental friendliness, high expansion ratio, small bulk density, high closed cell rate (closed cell rate ≥ 90%), high strength, high modulus, and high flame retardancy, and The flame-retardant polyester foam beads have a density of 80-200kg/m ³ , a foaming ratio of 5-20 times, and a cell size of 50-300μm. They can be used in automotive parts, rail transit, ships, refrigerated vehicles, and inside and outside buildings. Decoration, furniture filling and other fields.

Description

Flame-retardant polyester foam beads and its preparation method and application

technical field

The invention belongs to the field of polyester materials, and in particular relates to a flame-retardant polyester foamed bead, a preparation method and application thereof.

Background technique

Because the melt strength of polyester is very low, it will cause cell collapse, rupture, merger and other phenomena, that is, the cell wall cannot maintain a certain strength, so that effective bubbles cannot be formed, and it is necessary to improve the melt of polyester through reaction blending. body strength. During the foaming process, the pressure of the high-pressure reactor is very high. How to obtain higher-magnification foamed beads is also a major difficulty in the preparation of polyester bead foaming materials. At the same time, the flame retardant research and application development of polyester are becoming more and more active all over the world, but there is little research on flame retardant polyester foam beads.

Contents of the invention

The present invention aims to solve one of the technical problems in the related art at least to a certain extent. For this reason, an object of the present invention is to propose a kind of flame-retardant polyester foamed bead and its preparation method and application, and this flame-retardant polyester foamed bead has environment-friendly, high expansion ratio, small bulk density, High closed cell rate (closed cell rate ≥ 90%), high strength, high modulus, high flame retardancy and other excellent properties, and the flame-retardant polyester foam beads have a density of 80-200kg/m ³ , and the expansion ratio 5 to 20 times, cell size is 50 to 300 μm, can be used in automotive parts, rail transit, ships, refrigerated vehicles, building interior and exterior decoration, furniture filling and other fields.

In one aspect of the present invention, the present invention provides a kind of flame-retardant polyester foam beads. According to an embodiment of the present invention, the raw materials for forming the flame-retardant polyester foam beads include: polyester, chain extender, nucleating agent, flame retardant, antioxidant, surfactant and physical foaming agent .

Therefore, the flame-retardant polyester foam beads are environmentally friendly, high expansion ratio, small bulk density, high closed cell rate (closed cell rate ≥ 90%), high strength, high modulus, high flame retardancy, etc. characteristics, and the flame-retardant polyester foam beads have a density of 80-200kg/m ³ , a foaming ratio of 5-20 times, and a cell size of 50-300μm, which can be used in automotive parts, rail transit, ships, and refrigerated vehicles , building interior and exterior decoration, furniture filling and other fields.

In addition, the flame-retardant polyester foam beads according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some embodiments of the present invention, the mass ratio of the polyester, the chain extender, the nucleating agent, the flame retardant, the antioxidant and the surfactant is 100:( 0.2~1): (0.5~2): (6~15): (0.2~1): (0.2~1). Thus, flame-retardant polyester foam beads with excellent characteristics such as environmental friendliness, high expansion ratio, small bulk density, high closed cell ratio, high strength, high modulus, and high flame retardancy can be prepared.

In some embodiments of the present invention, the polyester includes at least one of PET, PBT, PTT, PCT, PEN, PLA, PETG, PBAT, PBS and TPEE.

In some embodiments of the present invention, the chain extender includes at least one of pyromellitic anhydride (PMDA), isocyanate (MDI), TGDDM and bisphenol A diglycidyl ether DGEBA. Thus, the melt strength of the polyester can be effectively improved and its "foamability" can be improved, and the phenomenon of foam collapse, cell rupture and cell merging during the foaming process can be effectively prevented.

In some embodiments of the present invention, the antioxidant includes at least one of the antioxidant 1010, the antioxidant 259 and the antioxidant 1330.

In some embodiments of the present invention, the surfactant includes at least one of polyether modified silicone oil (Shengbang SI-X221), simethicone oil (Dow Corning PMX140) and flame retardant silicone oil (Evonik B8525) .

In some embodiments of the present invention, the phosphorus content in the flame retardant is not less than 50000ppm. Thereby, the flame retardancy of the polyester expanded beads can be improved.

In some embodiments of the present invention, the flame retardant includes at least one of phosphorus-based flame retardants and phosphorus-nitrogen-based flame retardants.

In some embodiments of the present invention, the flame retardant is selected from aluminum diethyl hypophosphite ADP and polyphosphate HM1100, [(6-oxo-(6H)-dibenzo-(CE)(1,2 At least one of )-oxaphosphorin-6-one)methyl]-succinic acid (DDP), Clariant Exolit OP 550, Teijin FCX-210 and melamine cyanurate MCA.

In some embodiments of the present invention, the nucleating agent is a one-dimensional nucleating agent, and the aspect ratio of the one-dimensional nucleating agent is not lower than 20. Thus, the crystallization performance of the polyester can be improved, and the crystal grains can be refined, thereby improving the hardness and mechanical properties of the foamed beads.

In some embodiments of the present invention, the one-dimensional nucleating agent includes at least one of calcium carbonate whiskers, carbon nanotubes, nanofibers, sepiolite and attapulgite. Thus, the crystallization performance of the polyester can be improved, the crystal grains can be refined, and the hardness and mechanical properties of the foamed beads can be improved.

In some embodiments of the present invention, the physical blowing agent includes at least one of cyclopentane, HFC-152a, N ₂ and CO ₂ .

In some embodiments of the present invention, based on 100 parts by weight of the polyester, the physical blowing agent is used in an amount of 1-2.5 parts by weight.

In the second aspect of the present invention, the present invention proposes a method for preparing the above-mentioned flame-retardant polyester foam beads. According to an embodiment of the present invention, the method includes:

(1) After mixing polyester, chain extender, nucleating agent, flame retardant, antioxidant and surfactant, granulate through melt blending and extrusion, so as to obtain flame retardant polyester modified particles;

(2) Add the flame-retardant polyester-based modified particles into a dry high-pressure dipping kettle, inject a physical foaming agent to completely impregnate the flame-retardant polyester-based modified particles under high temperature and high pressure, to form a polymer/foaming agent homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank of step (2) to relieve pressure, forming an internal and external pressure drop, so that the homogeneous saturated system of the polymer/foaming agent is in a thermodynamically unstable state, driving Cells grow, and then cooled, washed, and dried to obtain flame-retardant polyester foam beads.

According to the method for preparing flame-retardant polyester foam beads according to the embodiment of the present invention, polyester elastomer, chain extender, nucleating agent, flame retardant, antioxidant and surfactant are mixed and melt-copolymerized Mixed extrusion for granulation, the addition of chain extenders can effectively increase the melt strength of polyester and improve its "foamability", and effectively prevent foam collapse, cell rupture and cell merging during the foaming process ; The nucleating agent forms a large number of low potential energy points at the interface between the melts during the foaming process, forming a large number of uniform nucleation hot spots, which is beneficial to the subsequent obtaining of higher-magnification expanded beads. The addition of flame retardants, 1) at high temperatures, decomposes to produce flammable or non-combustible gases, dilutes the concentration of flammable gases in the mixed gas around the material, and also reduces the oxygen content in the mixed gas, forming a gas protection around the combustibles Layer, while taking away a lot of heat, so as to achieve the purpose of flame retardancy. 2) The highly viscous liquid formed when the flame retardant is heated and melted or the foam structure formed when it is carbonized and foamed covers the surface of the combustible material, which prevents the heat transfer and oxygen transfer of the material from the external heat source, and also cuts off the Combustible materials decompose to produce flammable gases to escape, so as to achieve the purpose of flame retardancy. 3) When the combustible material reaches the temperature of thermal decomposition or spontaneous combustion, relying on the free radical inhibitor released by the flame retardant, it can capture the free radical released by the combustion reaction of the material, react with it to form non-combustible substances, and destroy the chain growth of the combustion reaction , so as to achieve the purpose of flame retardancy. There is a synergistic effect between the surfactant and the nucleating agent, heterogeneous nucleation, forming a large number of uniform nucleation hotspots, which is conducive to the subsequent obtaining of higher-magnification foaming beads; and the surfactant and polyester have better compatibility properties, can form a stable foam structure, prevent the cells from merging, reduce the foam opening rate, and at the same time act as a part of the high-temperature resistant lubricant; After mixing, the physical foaming agent is injected into the dry high-pressure dipping kettle. The physical foaming agent dissolves in the flame-retardant polyester modified particles at a certain temperature and vapor pressure to form a homogeneous saturated system of polymer/foaming agent. Finally, Open the discharge valve at the bottom of the dry high-pressure impregnation tank to relieve the pressure, forming internal and external pressure drop and thermodynamic instability, driving the cells to grow, and then cooling, cleaning, and drying to obtain environmentally friendly, high foaming ratio, small bulk density, High closed cell rate (closed cell rate ≥ 90%), high strength, high modulus, high flame retardancy and other excellent properties of flame-retardant polyester foam beads, and the obtained flame-retardant polyester foam beads density 80-200kg/m ³ , the expansion ratio is 5-20 times, and the cell size is 50-300μm. It can be used in automotive parts, rail transit, ships, refrigerated vehicles, building interior and exterior decoration, furniture filling and other fields.

In addition, the method for preparing flame-retardant polyester foam beads according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some embodiments of the present invention, in step (1), the particle diameter of the flame-retardant polyester-based modified particles is 0.5-1 mm.

In some embodiments of the present invention, in step (2), after injecting the physical foaming agent into the dry autoclave, control the vapor pressure in the dry autoclave to be 10-30MPa, and the temperature to be 130 ~270°C. Thus, the physical foaming agent is completely impregnated with the flame-retardant polyester modified particles, forming a polymer/foaming agent homogeneous saturated system.

In the third aspect of the present invention, the present invention provides a foamed shaped part. According to an embodiment of the present invention, the foamed special-shaped part is prepared by using the above-mentioned flame-retardant polyester foam beads or the flame-retardant polyester foam beads prepared by the above-mentioned method. Therefore, the foamed special-shaped part has excellent characteristics such as environmental friendliness, high expansion ratio, small bulk density, high closed cell rate (closed cell rate ≥ 90%), high strength, high modulus, high flame retardancy, etc., and can be used in automobiles. Components, rail transit, ships, refrigerated vehicles, building interior and exterior decoration, furniture filling and other fields.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and understandable from the description of the embodiments in conjunction with the following drawings, wherein:

1 is a schematic flow diagram of a method for preparing flame-retardant polyester foam beads according to an embodiment of the present invention;

Fig. 2 is the physical figure of embodiment 1 foamed beads;

Fig. 3 is the SEM topography diagram of the cross-section of the expanded beads in Example 2.

Detailed ways

The following detailed descriptions of the embodiments of the present invention are intended to explain the present invention, but should not be construed as limiting the present invention.

In one aspect of the present invention, the present invention proposes a flame-retardant polyester foamed bead, and the raw materials for forming the flame-retardant polyester foamed bead include: polyester, chain extender, nucleating agent, Flame retardants, antioxidants, surfactants and physical blowing agents.

The inventors found that the addition of chain extenders can effectively increase the melt strength of polyester and improve its "foamability", and effectively prevent foam collapse, cell rupture and cell merging in the foaming process; nucleation During the foaming process, the agent forms a large number of low-potential energy points at the interface between the melts, forming a large number of uniform nucleation hotspots, which is beneficial to the subsequent obtaining of higher-magnification expanded beads. The addition of flame retardants, 1) at high temperatures, decomposes to produce flammable or non-combustible gases, dilutes the concentration of flammable gases in the mixed gas around the material, and also reduces the oxygen content in the mixed gas, forming a gas protection around the combustibles Layer, while taking away a lot of heat, so as to achieve the purpose of flame retardancy. 2) The highly viscous liquid formed when the flame retardant is heated and melted or the foam structure formed when it is carbonized and foamed covers the surface of the combustible material, which prevents the heat transfer and oxygen transfer of the material from the external heat source, and also cuts off the Combustible materials decompose to produce flammable gases to escape, so as to achieve the purpose of flame retardancy. 3) When the combustible material reaches the temperature of thermal decomposition or spontaneous combustion, relying on the free radical inhibitor released by the flame retardant, it can capture the free radical released by the combustion reaction of the material, react with it to form non-combustible substances, and destroy the chain growth of the combustion reaction , so as to achieve the purpose of flame retardancy. There is a synergistic effect between the surfactant and the nucleating agent, heterogeneous nucleation, forming a large number of uniform nucleation hotspots, which is conducive to the subsequent obtaining of higher-magnification foaming beads; and the surfactant and polyester have better compatibility It can form a stable foam structure, prevent cells from merging, reduce the foam opening rate, and at the same time act as a part of high temperature resistant lubricant. Thus, the expanded beads have high mechanical properties and high flame retardancy.

Further, the mass ratio of the polyester, chain extender, nucleating agent, flame retardant, antioxidant and surfactant is 100:(0.2～1):(0.5～2):(6～15): (0.2～1): (0.2～1). The inventors have found that if the chain extender is added too high, the melt will be gel-like, similar to the rubber state, and the color will become darker, which is unfavorable for extrusion; and if the chain extender is added too low, it will not be able to support the growth of the foam. If the nucleating agent is added too much, it will form agglomeration, which is not conducive to the formation of a uniform cell structure; and if the nucleating agent is added too low, the ideal nucleation effect will not be obtained, and the heterogeneous nucleation point If the amount of antioxidant is too low, a dense foam structure cannot be formed; and if the amount of antioxidant added is too high, the anti-oxidation stabilization effect will no longer increase, and there will be precipitation; and if the amount of antioxidant added is too low, the oxidation resistance of the material cannot be effectively reduced. Cause material discoloration and degradation; if the amount of flame retardant added is too low, the flame retardant effect will not be obvious, and if the amount of flame retardant added is too high, the mechanical properties of the material will decrease, the viscoelasticity of polyester will decrease, and high-performance foam cannot be obtained. Bubble beads: If the surfactant is added too high, it will cause agglomeration, and the effect will not increase significantly, which is not conducive to the formation of a uniform cell structure. If the surfactant is added too low, the surface tension cannot be effectively reduced.

According to an embodiment of the present invention, the polyester includes at least one of PET, PBT, PTT, PCT, PEN, PLA, PBAT, PETG, PBS and TPEE.

Further, the above-mentioned chain extenders include but are not limited to at least one of pyromellitic anhydride (PMDA), isocyanate (MDI), TGDDM and bisphenol A diglycidyl ether DGEBA, and antioxidants include but are not limited to At least one of the oxygen agent 1010, the antioxidant agent 259 and the antioxidant agent 1330. And the phosphorus content in the above flame retardant is not less than 50000ppm. The inventors found that if the phosphorus content of the flame retardant is lower than 50000ppm, the flame retardancy of the foamed beads is not good, and the oxygen index of the foamed beads is lower than 26%. Preferably, the flame retardants include phosphorus flame retardants and phosphorus nitrogen flame retardants, including aluminum diethyl hypophosphite ADP, polyphosphate HM1100, [(6-oxygen-(6H)-dibenzo-(CE )(1,2)-oxaphosphorin-6-one)methyl]-succinic acid (DDP), Clariant ExolitOP 550, Teijin FCX-210 and melamine cyanurate MCA kind. Specifically, phosphorus-based flame retardants are decomposed by heat to produce strong acids (such as polyphosphoric acid and pyrophosphoric acid) with water absorption or dehydration effects. Combustible materials are separated from oxidants and heat sources to prevent the transfer of substances and heat, so as to prevent the progress of combustion.

Further, the above-mentioned nucleating agent is a one-dimensional nucleating agent. The inventors have found that the addition of a one-dimensional structure nucleating agent can improve the crystallization properties of the polyester and refine the crystal grains, thereby improving the hardness of the foamed beads. A large number of low potential energy points are formed at the interface, heterogeneous nucleation, and a large number of uniform nucleation hotspots are formed, which is conducive to the subsequent obtaining of higher-magnification expanded beads. In addition, compared with other structural nucleating agents (such as flaky, spherical, etc.), the addition of one-dimensional structural nucleating agents improves the mechanical properties of foamed products more significantly. Preferably, the aspect ratio of the one-dimensional structure nucleating agent is not lower than 20. The inventors have found that the one-dimensional nucleating agent has a certain length-to-diameter ratio (L/D), and the larger the L/D, the better the reinforcing effect. Compared with other structural nucleating agents (such as flakes, spherical shapes, etc.), The addition of one-dimensional nucleating agent can improve the mechanical properties of foam products more obviously. For example, one-dimensional nucleating agents include but are not limited to at least one of calcium carbonate whiskers, carbon nanotubes, nanofibers, sepiolite and attapulgite.

Further, the above-mentioned surfactants include but are not limited to at least one of polyether-modified silicone oil, dimethyl silicone oil and flame-retardant silicone oil. The inventors have found that this type of surfactant has a synergistic effect with the above-mentioned nucleating agent, nucleates in heterogeneous phases, and forms a large number of uniform nucleation hotspots, thereby facilitating the subsequent obtaining of higher-magnification expanded beads; and this type of surfactant It has good compatibility with polyester, can form a stable foam structure, prevent cell merging, reduce the foam opening rate, and at the same time act as a part of high temperature resistant lubricant; in addition, the flame retardant silicone oil surfactant has high activity , while ensuring the flame retardant performance of the beads, the amount of flame retardant added is reduced, saving costs. In addition, it also solves the problem of the decrease in melt strength caused by the addition of flame retardants, and improves the performance of foamed beads with the addition of flame retardants. and reduce the problem.

In the second aspect of the present invention, the present invention proposes a method for preparing the above-mentioned flame-retardant polyester foam beads. According to an embodiment of the present invention, with reference to Fig. 1, the method includes:

S100: After mixing polyester, chain extender, nucleating agent, flame retardant, antioxidant and surfactant, it is granulated by melt blending and extrusion

In this step, the polyester, chain extender, nucleating agent, flame retardant, antioxidant and surfactant are mixed and granulated by melt blending and extruding to obtain a flame retardant polymer with a particle size of 0.5-1mm. Ester modified particles. The inventors found that the addition of chain extenders can effectively increase the melt strength of polyester and improve its "foamability", and effectively prevent foam collapse, cell rupture and cell merging in the foaming process; nucleation During the foaming process, the agent forms a large number of low-potential energy points at the interface between the melts, forming a large number of uniform nucleation hotspots, which is beneficial to the subsequent obtaining of higher-magnification expanded beads. The addition of flame retardants, 1) at high temperatures, decomposes to produce flammable or non-combustible gases, dilutes the concentration of flammable gases in the mixed gas around the material, and also reduces the oxygen content in the mixed gas, forming a gas protection around the combustibles Layer, while taking away a lot of heat, so as to achieve the purpose of flame retardancy. 2) The highly viscous liquid formed when the flame retardant is heated and melted or the foam structure formed when it is carbonized and foamed covers the surface of the combustible material, which prevents the heat transfer and oxygen transfer of the material from the external heat source, and also cuts off the Combustible materials decompose to produce flammable gases to escape, so as to achieve the purpose of flame retardancy. 3) When the combustible material reaches the temperature of thermal decomposition or spontaneous combustion, relying on the free radical inhibitor released by the flame retardant, it can capture the free radical released by the combustion reaction of the material, react with it to form non-combustible substances, and destroy the chain growth of the combustion reaction , so as to achieve the purpose of flame retardancy. There is a synergistic effect between the surfactant and the above-mentioned nucleating agent, heterogeneous nucleation, forming a large number of uniform nucleation hotspots, which is beneficial to the subsequent obtaining of higher-magnification foaming beads; and this type of surfactant has better affinity with polyester. Compatibility, can form a stable foam structure, prevent cells from merging, reduce the foam opening rate, and at the same time play a role in part of the high temperature resistant lubricant. Thus, the expanded beads have high mechanical properties and high flame retardancy.

Further, the mass ratio of the polyester, chain extender, nucleating agent, flame retardant, antioxidant and surfactant is 100:(0.2～1):(0.5～2):(6～15): (0.2～1): (0.2～1). The inventors have found that if the chain extender is added too high, the melt will be gel-like, similar to the rubber state, and the color will become darker, which is unfavorable for extrusion; and if the chain extender is added too low, it will not be able to support the growth of the foam. If the nucleating agent is added too much, it will form agglomeration, which is not conducive to the formation of a uniform cell structure; and if the nucleating agent is added too low, the ideal nucleation effect will not be obtained, and the heterogeneous nucleation point If the amount of antioxidant is too low, a dense foam structure cannot be formed; and if the amount of antioxidant added is too high, the anti-oxidation stabilization effect will no longer increase, and there will be precipitation; and if the amount of antioxidant added is too low, the oxidation resistance of the material cannot be effectively reduced. Cause material discoloration and degradation; if the amount of flame retardant added is too low, the flame retardant effect will not be obvious, and if the amount of flame retardant added is too high, the mechanical properties of the material will decrease, the viscoelasticity of polyester will decrease, and high-performance foam cannot be obtained. Bubble beads: If the surfactant is added too high, it will cause agglomeration, and the effect will not increase significantly, which is not conducive to the formation of a uniform cell structure. If the surfactant is added too low, the surface tension cannot be effectively reduced.

According to an embodiment of the present invention, the polyester includes at least one of PET, PBT, PTT, PCT, PEN, PLA, PETG, PBAT, PBS and TPEE.

Further, the above-mentioned chain extenders include but are not limited to at least one of pyromellitic anhydride (PMDA), isocyanate (MDI), TGDDM and bisphenol A diglycidyl ether DGEBA, and antioxidants include but are not limited to At least one of the oxygen agent 1010, the antioxidant agent 259 and the antioxidant agent 1330. And the phosphorus content in the above flame retardant is not less than 50000ppm. The inventors found that if the phosphorus content of the flame retardant is lower than 50000ppm, the flame retardancy of the foamed beads is not good, and the oxygen index of the foamed beads is lower than 26%. Preferably, the flame retardants include phosphorus flame retardants and phosphorus nitrogen flame retardants, including aluminum diethyl hypophosphite ADP, polyphosphate HM1100, [(6-oxygen-(6H)-dibenzo-(CE )(1,2)-oxaphosphorin-6-one)methyl]-succinic acid (DDP), Clariant ExolitOP 550, Teijin FCX-210 and melamine cyanurate MCA kind. Specifically, phosphorus-based flame retardants are decomposed by heat to produce strong acids (such as polyphosphoric acid and pyrophosphoric acid) with water absorption or dehydration effects. Combustible materials are separated from oxidants and heat sources to prevent the transfer of substances and heat, so as to prevent the progress of combustion.

Further, the above-mentioned nucleating agent is a one-dimensional nucleating agent. The inventors have found that the addition of a one-dimensional structure nucleating agent can improve the crystallization properties of the polyester and refine the crystal grains, thereby improving the hardness of the foamed beads. A large number of low potential energy points are formed at the interface, heterogeneous nucleation, and a large number of uniform nucleation hotspots are formed, which is conducive to the subsequent obtaining of higher-magnification expanded beads. In addition, compared with other structural nucleating agents (such as flaky, spherical, etc.), the addition of one-dimensional structural nucleating agents improves the mechanical properties of foamed products more significantly. Preferably, the aspect ratio of the one-dimensional structure nucleating agent is not lower than 20. The inventors found that the acicular nucleating agent has a certain length-to-diameter ratio (L/D), the larger the L/D, the better the reinforcing effect, compared with other structural nucleating agents (such as flake, spherical, etc.), The addition of needle-shaped nucleating agent can improve the mechanical properties of foam products more obviously. For example, one-dimensional nucleating agents include but are not limited to at least one of calcium carbonate whiskers, carbon nanotubes, nanofibers, sepiolite and attapulgite.

Further, the above-mentioned surfactants include but are not limited to at least one of polyether-modified silicone oil, dimethyl silicone oil and flame-retardant silicone oil. The inventors have found that this type of surfactant has a synergistic effect with the above-mentioned nucleating agent, nucleates in heterogeneous phases, and forms a large number of uniform nucleation hotspots, thereby facilitating the subsequent obtaining of higher-magnification expanded beads; and this type of surfactant It has good compatibility with polyester, can form a stable foam structure, prevent cell merging, reduce the foam opening rate, and at the same time act as a part of high temperature resistant lubricant; in addition, the flame retardant silicone oil surfactant has high activity , while ensuring the flame retardant performance of the beads, the amount of flame retardant added is reduced, saving costs. In addition, it also solves the problem of the decrease in melt strength caused by the addition of flame retardants, and improves the performance of foamed beads with the addition of flame retardants. and reduce the problem.

S200: Add flame-retardant polyester modified particles into dry high-pressure impregnation kettle, inject physical foaming agent to completely impregnate flame-retardant polyester modified particles under high temperature and high pressure

In this step, the flame-retardant polyester modified particles obtained by the above-mentioned granulation are added into a dry-type high-pressure impregnation kettle, and then the physical foaming agent is injected into the dry-type high-pressure impregnation kettle through high pressure. Under the condition of vapor pressure of 10-30MPa, the physical foaming agent and flame-retardant polyester modified particles can achieve better infiltration, forming a polymer/foaming agent homogeneous saturated system.

Further, according to an embodiment of the present invention, the above-mentioned physical blowing agent includes but is not limited to at least one of cyclopentane, HFC-152a, _N2 and _CO2 ; and based on 100 parts by mass of the polyester, The amount of the physical blowing agent is 1-2.5 parts by weight. The inventors found that if the amount of foaming agent added is too high, due to the limited solubility of the foaming agent in the flame-retardant polyester modified particles, the excess foaming agent does not participate in the cell growth process, but instead causes the foam to merge. ; And if the amount of foaming agent added is too low, it will result in low foaming ratio and insignificant weight loss.

S300: Open the discharge valve at the bottom of the dry high-pressure impregnation tank in step S200 to relieve pressure, forming an internal and external pressure drop

In this step, the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step S200 is opened to relieve pressure, forming an internal and external pressure drop, making the polymer/foaming agent homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, Then cool, wash, and dry to obtain flame-retardant polyester foam beads.

In the second aspect of the present invention, the present invention provides a kind of flame-retardant polyester foam beads. According to an embodiment of the present invention, the flame-retardant polyester foam beads are prepared by the above method. Therefore, the flame-retardant polyester foamed beads have excellent characteristics such as environmental friendliness, high expansion ratio, small bulk density, high closed cell ratio, high strength, high modulus, and high flame retardancy, and the obtained flame-retardant polymer The density of ester foamed beads is 80-200kg/m ³ , the expansion ratio is 5-20 times, the closed cell rate is ≥90%, the cell size is 50-300μm, the strength is ≥1.5MPa, the modulus is ≥100MPa, and the oxygen index is ≥30%, can be used in auto parts, shoe materials, rail transit, construction, packaging, furniture filling, cement filling and other fields.

It should be noted that the features and advantages described above for the method for preparing flame-retardant polyester foam beads are also applicable to the flame-retardant polyester foam beads, and will not be repeated here.

In the third aspect of the present invention, the present invention provides a foamed shaped part. According to an embodiment of the present invention, the foamed special-shaped part is prepared by using the above-mentioned flame-retardant polyester foam beads or the flame-retardant polyester foam beads prepared by the above-mentioned method. Therefore, the foamed special-shaped part has excellent characteristics such as environmental friendliness, high expansion ratio, small bulk density, high closed cell rate (closed cell rate ≥ 90%), high strength, high modulus, high flame retardancy, etc., and can be used in automobiles. Components, rail transit, ships, refrigerated vehicles, building interior and exterior decoration, furniture filling and other fields.

It should be noted that the features and advantages described above for the flame-retardant polyester foamed beads and the preparation method thereof are also applicable to the foamed special-shaped part, and will not be repeated here.

Embodiments of the present invention are described in detail below, and it should be noted that the embodiments described below are exemplary, and are only used to explain the present invention, and should not be construed as limiting the present invention. In addition, if not clearly stated, all reagents used in the following examples are commercially available, or can be synthesized according to this article or known methods, and for the reaction conditions not listed, they are all readily available to those skilled in the art.

Comparative example 1

(1) 100 parts by weight of PET, 0.5 parts by weight of PMDA, 0.5 parts by weight of calcium carbonate whiskers (length-to-diameter ratio is 80), 0.5 parts by weight of antioxidant 1010, and 0.2 parts by weight of Evonik B8525 are mixed uniformly in proportion, and double The screw extruder (Coperion STS-50MC11) melts and extrudes at 260°C to obtain 0.8mm PET modified particles;

(2) Add the above-mentioned PET modified particles into a dry high-pressure impregnation kettle, then inject 2 parts by weight of CO ₂ , and impregnate the PET modified particles for 6 hours at a vapor pressure of 25 MPa and 260°C to form a PET/CO ₂ homogeneously saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step (2) to relieve pressure, forming an internal and external pressure drop, making the PET/ _CO2 homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, and then After cooling, washing and drying, PET foam beads are obtained.

Example 1

(1) 100 parts by weight of PET, 0.5 parts by weight of PMDA, 0.5 parts by weight of calcium carbonate whiskers (the aspect ratio is 80), 6 parts by weight of aluminum diethylphosphinate ADP (the phosphorus content is 230000ppm), 0.5 parts by weight of anti- Oxygen agent 1010, 0.2 parts by weight of flame-retardant silicone oil (Evonik B8525) were mixed evenly in proportion, melted and extruded at 260°C by twin-screw extruder (Coperion STS-50MC11) to obtain 0.8mm PET modified particles;

(2) Add the above-mentioned flame-retardant PET modified particles into a dry high-pressure impregnation kettle, then inject 2 parts by weight of CO ₂ , impregnate the flame-retardant PET modified particles for 6 hours at a vapor pressure of 24MPa and 260°C to form a PET/CO ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step (2) to relieve pressure, forming an internal and external pressure drop, making the PET/ _CO2 homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, and then After cooling, washing, and drying, flame-retardant PET foam beads were obtained, and the actual picture thereof is shown in Figure 1.

Example 2

(1) 100 parts by weight of PET, 0.5 parts by weight of PMDA, 0.5 parts by weight of calcium carbonate whiskers (the aspect ratio is 80), 6 parts by weight of aluminum diethylphosphinate ADP (the phosphorus content is 230000ppm), 0.5 parts by weight of anti- Oxygen agent 1010 and 1 weight part of flame retardant silicone oil (Evonik B8525) were uniformly mixed in proportion, melted and extruded at 260°C to obtain 0.8mm flame retardant PET modified particles;

(2) Add the above-mentioned flame-retardant PET modified particles into a dry high-pressure impregnation kettle, then inject 2 parts by weight of CO ₂ , impregnate the flame-retardant PET modified particles for 6 hours at a vapor pressure of 23 MPa and 260°C to form a PET/CO ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step (2) to relieve pressure, forming an internal and external pressure drop, making the PET/ _CO2 homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, and then After cooling, washing, and drying, flame-retardant PET foam beads were obtained, and the cross-sectional SEM image is shown in Figure 3.

Example 3

(1) 100 parts by weight of PBT, 0.5 parts by weight of PMDA, 0.5 parts by weight of calcium carbonate whiskers (aspect ratio of 80), 12 parts by weight of polyphosphate HM1100 (phosphorus content of 105000ppm), 0.5 parts by weight of antioxidant 1010 , 0.5 parts by weight of flame-retardant silicone oil (Evonik B8525) were mixed evenly in proportion, melted and extruded at 220°C by twin-screw extruder (Coperion STS-50MC11) to obtain 0.6mm flame-retardant PBT modified particle;

(2) Add the above-mentioned flame-retardant PBT modified particles into a dry high-pressure impregnation kettle, then inject 2 parts by weight of CO ₂ , impregnate the flame-retardant PBT modified particles for 5 hours at a vapor pressure of 24MPa and 220°C to form a PBT/CO ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank of step (2) to relieve pressure, forming an internal and external pressure drop, making the PBT/ _CO Homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow up, and then After cooling, washing and drying, flame-retardant PBT foam beads are obtained.

Example 4

(1) 100 parts by weight of PTT, 0.5 parts by weight of PMDA, 0.5 parts by weight of calcium carbonate whiskers (aspect ratio of 80), 10 parts by weight of [(6-oxygen-(6H)-dibenzo-(CE)( 1,2)-Oxaphosphorin-6-one)methyl]-succinic acid (DDP) (phosphorus content is 140000ppm), 0.2 parts by weight of antioxidant 1330, 0.5 parts by weight of flame retardant silicone oil (Evonik B8525 ) are evenly mixed, melted and extruded at 230°C by a twin-screw extruder (Coperion STS-50MC11) to obtain 0.5mm flame-retardant polyester PTT;

(2) Add the above-mentioned flame-retardant PTT modified particles into a dry high-pressure impregnation kettle, then inject 2.5 parts by weight of N ₂ , impregnate the flame-retardant PTT modified particles for 6 hours at a vapor pressure of 20 MPa and 210°C to form a PTT/N ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank of step (2) to relieve pressure, forming an internal and external pressure drop, making the PTT/ _N homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, and then After cooling, washing and drying, flame-retardant PTT foam beads are obtained.

Example 5

(1) 100 parts by weight of PCT, 1 part by weight of MDI, 0.5 parts by weight of calcium carbonate whiskers (the aspect ratio is 80), 8 parts by weight of Exolit OP 550 (the phosphorus content is 170000ppm), 1 part by weight of antioxidant 259, 0.5 parts by weight of flame-retardant silicone oil (Evonik B8525) was uniformly mixed in proportion, melted and extruded at 270°C by a twin-screw extruder (Coperion STS-50MC11) to obtain 0.5mm flame-retardant PCT modified particles ;

(2) Add the above-mentioned flame-retardant PCT modified particles into a dry high-pressure impregnation kettle, then inject 2.5 parts by weight of N ₂ , impregnate the flame-retardant PCT modified particles for 5 hours at a vapor pressure of 23MPa and 270°C to form a PCT/N ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank of step (2) to relieve pressure, forming an internal and external pressure drop, making the PCT/ _N homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow up, and then After cooling, washing and drying, flame-retardant PCT foam beads are obtained.

Example 6

(1) 100 parts by weight of PEN, 1 part by weight of MDI, 0.8 parts by weight of carbon nanotubes (the aspect ratio is 1000), 12 parts by weight of Teijin FCX-210 (the phosphorus content is 150000ppm), 0.5 parts by weight of antioxidant 1010, 1 part by weight of polyether modified silicone oil (Shengbang SI-X221) was mixed evenly in proportion, melted and extruded at 265°C by a twin-screw extruder (Coperion STS-50MC11) to obtain 1mm flame-retardant PEN Modified particles;

(2) Add the above-mentioned flame-retardant PEN modified particles into a dry high-pressure impregnation kettle, then inject 1.5 parts by weight of HFC-152a, and impregnate the flame-retardant PEN modified particles for 7 hours at a vapor pressure of 22MPa and 265°C to form a PEN/ HFC-152a homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step (2) to relieve pressure, forming an internal and external pressure drop, making the PEN/HFC-152a homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow up, After cooling, washing and drying, flame-retardant PEN foam beads are obtained.

Example 7

(1) 100 parts by weight of PLA, 1 part by weight of MDI, 0.8 parts by weight of carbon nanotubes (the aspect ratio is 1000), 10 parts by weight of melamine cyanurate MCA (the phosphorus content is 200000ppm), 0.5 parts by weight of antioxidant 1010, 0.5 parts by weight of polyether modified silicone oil (Shengbang SI-X221) were mixed evenly in proportion, melted and extruded at 190°C by a twin-screw extruder (Coperion STS-50MC11) to obtain 1mm resistance Burn PLA modified particles;

(2) Add the above-mentioned flame-retardant PLA modified particles into a dry-type high-pressure impregnation kettle, then inject 1.5 parts by weight of HFC-152a, and impregnate the flame-retardant PLA modified particles at a vapor pressure of 15 MPa and 190°C for 6 hours to form PLA/ HFC-152a homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step (2) to relieve pressure, forming an internal and external pressure drop, making the PLA/HFC-152a homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow up, Then cool, wash, and dry to obtain flame-retardant PLA foam beads.

Example 8

(1) 100 parts by weight of PETG, 0.2 parts by weight of TGDDM, 1 part by weight of nanofibers (the aspect ratio is 80), 10 parts by weight of polyphosphate HM1100 (the phosphorus content is 105000ppm), 0.5 parts by weight of antioxidant 1330, 0.5 parts by weight Parts by weight of flame-retardant silicone oil (Evonik B8525) were mixed uniformly in proportion, melted and extruded at 220°C through a twin-screw extruder (Coperion STS-50MC11) to obtain 0.7mm flame-retardant PETG modified particles;

(2) Add the above-mentioned flame-retardant PETG modified particles into a dry high-pressure impregnation kettle, then inject 1.5 parts by weight of CO ₂ , and impregnate the flame-retardant PETG modified particles for 6.8 hours at a vapor pressure of 20 MPa and 225°C to form a PETG/ CO ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step (2) to relieve pressure, forming an internal and external pressure drop, making the PETG/ _CO2 homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, and then After cooling, washing and drying, flame-retardant PETG foam beads are obtained.

Example 9

(1) 100 parts by weight of PBAT, 0.5 parts by weight of TGDDM, 1 part by weight of attapulgite (aspect ratio of 50), 12 parts by weight of [(6-oxo-(6H)-dibenzo-(CE) (1 ,2)-Oxaphosphorin-6-one)methyl]-succinic acid (DDP) (phosphorus content is 140000ppm), 0.5 parts by weight of antioxidant 259, 0.6 parts by weight of simethicone oil (Dow Corning PMX140) Mix evenly in proportion, melt and extrude at 140°C through a twin-screw extruder (Coperion STS-50MC11) to obtain 0.8mm flame-retardant PBAT modified particles;

(2) Add the above-mentioned flame-retardant PBAT modified particles into a dry-type high-pressure impregnation kettle, then inject 1.5 parts by weight of cyclopentane, and impregnate the flame-retardant PBAT modified particles at a vapor pressure of 20 MPa and 135°C for 7 hours to form a PBAT/ Cyclopentane homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank of step (2) to relieve pressure, forming an internal and external pressure drop, making the PBAT/cyclopentane homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow up, After cooling, washing and drying, flame-retardant PBAT foam beads are obtained.

Example 10

(1) 100 parts by weight of PBS, 0.4 parts by weight of bisphenol A diglycidyl ether DGEBA, 1 part by weight of attapulgite (aspect ratio of 50), 12 parts by weight of Teijin FCX-210 (phosphorus content of 150000ppm), 0.5 259 parts by weight of antioxidant and 0.5 parts by weight of simethicone oil (Dow Corning PMX140) were mixed evenly in proportion, melted and extruded at 190°C by a twin-screw extruder (Coperion STS-50MC11) to obtain 0.5mm Flame retardant PBS modified particles;

(2) Add the above-mentioned flame-retardant PBS modified particles into a dry high-pressure impregnation kettle, then inject 2 parts by weight of CO ₂ , and impregnate the flame-retardant PBS modified particles at 190°C for 7 hours at a vapor pressure of 18 MPa to form a PBS/CO ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank of step (2) to relieve pressure, forming an internal and external pressure drop, making the PBS/ _CO Homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, and then After cooling, washing and drying, flame-retardant PBS foam beads are obtained.

Example 11

(1) 100 parts by weight of TPEE, 0.5 parts by weight of bisphenol A diglycidyl ether DGEBA, 2 parts by weight of sepiolite (the aspect ratio is 40), 8 parts by weight of Clariant Exolit OP 550 (the phosphorus content is 170000ppm), 0.5 parts by weight of antioxidant 259 and 0.6 parts by weight of simethicone oil (Dow Corning PMX140) were uniformly mixed in proportion, melted and extruded at 220° C. to obtain 0.8 mm flame retardant TPEE modified particles;

(2) Add the above-mentioned flame-retardant TPEE modified particles into a dry high-pressure impregnation kettle, then inject 2.5 parts by weight of N ₂ , impregnate the flame-retardant TPEE modified particles for 7 hours at a vapor pressure of 20 MPa and 220°C to form TPEE/N ₂ homogeneous saturated system;

(3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank in step (2) to relieve pressure, forming an internal and external pressure drop, making the TPEE/ _N homogeneous saturation system in a thermodynamically unstable state, driving the cells to grow, and then After cooling, washing and drying, flame-retardant TPEE foam beads are obtained.

evaluate:

1. Evaluate the foam density, expansion ratio, cell size, closed cell ratio, strength, modulus and flame retardancy of the flame-retardant polyester foam beads obtained in Comparative Example 1 and Examples 1-11;

2. Performance evaluation method of flame-retardant polyester foam beads:

Foam density: according to GB/T 6343-86

Foaming ratio: the ratio of the density of the material after foaming to the density before foaming

Cell Size: Scanning Electron Microscope (SEM) Size Calibration

Closed cell rate: in accordance with GB/T10799-1989 "Test method for open cell and closed cell volume percentage of rigid foam plastics"

Strength: According to ISO 844 "Determination of Compressive Properties of Rigid Foam Materials"

Modulus: According to ISO 844 "Determination of Compressive Properties of Rigid Foam Materials"

Flame retardancy: according to GB/T2406.2-2009 foam material oxygen index test

The test results of the flame-retardant polyester foamed beads obtained in Comparative Example 1 and Examples 1-11 are shown in Table 1, and the oxygen index test chart of the expanded beads is shown in Figure 2 .

Table 1 comparative example 1 and embodiment 1-11 gained polyester foamed bead performance data

In the description of this specification, descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific examples", or "some examples" mean that specific features described in connection with the embodiment or example , structure, material or characteristic is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention, those skilled in the art can make the above-mentioned The embodiments are subject to changes, modifications, substitutions and variations.

Claims (11)

1. A flame-retardant polyester foamed bead, is characterized in that, the raw material that forms described flame-retardant polyester foamed bead comprises: polyester, chain extender, nucleating agent, flame retardant, anti- Oxygenating agents, surfactants and physical blowing agents. 2. The expanded beads according to claim 1, characterized in that, the polyester, the chain extender, the nucleating agent, the fire retardant, the antioxidant and the surface The mass ratio of the active agent is 100:(0.2-1):(0.5-2):(6-15):(0.2-1):(0.2-1). 3. The foamed beads according to claim 1 or 2, wherein the polyester comprises at least one of PET, PBT, PTT, PCT, PEN, PLA, PBAT, PETG, PBS and TPEE. Optionally, the chain extender includes at least one of pyromellitic anhydride, isocyanate, TGDDM and bisphenol A diglycidyl ether. 4. The expanded beads according to claim 1 or 2, wherein the antioxidant comprises at least one of antioxidant 1010, antioxidant 259 and antioxidant 1330; Optionally, the surfactant includes at least one of polyether-modified silicone oil, dimethyl silicone oil and flame-retardant silicone oil. 5. The expanded beads according to claim 1 or 2, characterized in that, the phosphorus content in the flame retardant is not less than 50000ppm; Optionally, the flame retardant includes at least one of a phosphorus flame retardant and a phosphorus nitrogen flame retardant; The flame retardant is selected from aluminum diethyl hypophosphite and polyphosphate, [(6-oxo-(6H)-dibenzo-(CE)(1,2)-oxaphosphorin-6-ketone ) at least one of methyl]-succinic acid, Exolit OP 550, FCX-210 and melamine cyanurate. 6. The foamed beads according to claim 1 or 2, wherein the nucleating agent is a one-dimensional nucleating agent, and the aspect ratio of the one-dimensional nucleating agent is not less than 20; Optionally, the one-dimensional nucleating agent includes at least one of calcium carbonate whiskers, carbon nanotubes, nanofibers, sepiolite and attapulgite. 7. expanded beads according to claim 1, is characterized in that, described physical blowing agent comprises cyclopentane, HFC-152a, N ₂ and CO At least _one in; Optionally, based on 100 parts by mass of the polyester, the physical blowing agent is used in an amount of 1-2.5 parts by weight. 8. A method for preparing the flame-retardant polyester foam beads described in any one of claims 1-7, characterized in that, comprising: (1) After mixing polyester, chain extender, nucleating agent, flame retardant, antioxidant and surfactant, granulate through melt blending and extrusion, so as to obtain flame retardant polyester modified particles; (2) Add the flame-retardant polyester-based modified particles into a dry high-pressure dipping kettle, inject a physical foaming agent to completely impregnate the flame-retardant polyester-based modified particles under high temperature and high pressure, to form a polymer/foaming agent homogeneous saturated system; (3) Open the discharge valve at the bottom of the dry-type high-pressure impregnation tank of step (2) to relieve pressure, forming an internal and external pressure drop, so that the homogeneous saturated system of the polymer/foaming agent is in a thermodynamically unstable state, driving Cells grow, and then cooled, washed, and dried to obtain flame-retardant polyester foam beads. 9. The method according to claim 8, characterized in that, in step (1), the particle diameter of the flame-retardant polyester modified particles is 0.5-1 mm. 10. The method according to claim 8, characterized in that, in step (2), after the physical blowing agent is injected into the dry autoclave, the vapor pressure in the dry autoclave is controlled to be 10-30MPa, the temperature is 130-270°C. 11. A special-shaped foaming part, characterized in that, the special-shaped foaming part adopts the flame-retardant polyester foam beads according to any one of claims 1-7 or any one of claims 8-10. The flame-retardant polyester foam beads prepared by one of the methods are prepared.

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