Enhanced flame-retardant polyester composite material for baking all-in-one machine shell and preparation method thereof

Abstract

The present application relates to the technical field of polyester composite material, in particular to a reinforced flame-retardant polyester composite material for baking integrated machine shell and a preparation method thereof, the composite material takes polybutylene terephthalate and poly(1,4-cyclohexylenedimethylene terephthalate) as main raw materials, and higher heat distortion temperature, heat resistance and high strength are obtained by the cooperation of the two, the polybutylene terephthalate has better fatigue resistance and size stability, and smaller creep; the grafting modification thermoplastic polyester elastomer is added, the special heat-sensitive hydrophobicity and the toughening property of the thermoplastic polyester elastomer are utilized, and the toughening agent and the antioxidant are synergistically used to improve the hydrolysis resistance, high-temperature and high-humidity weather resistance, high-low temperature impact toughness and low shrinkage of the polyester composite material; the synergistic flame-retardant effect of the added bromine-based flame retardant and halogen-free flame retardant can meet the flame-retardant requirements of the material; the glass fiber has the effects of hydrolysis resistance and low warping, and the low shrinkage can promote the structure of the product to be flat, and the polyester composite material is particularly suitable for producing baking integrated machine shell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyester composite materials, in particular to a reinforced flame-retardant polyester composite material for an oven all-in-one machine shell and a preparation method thereof. BACKGROUND

[0002] An oven all-in-one machine, also commonly known as a steam and oven all-in-one machine, is a kitchen appliance that combines the functions of a steam oven and an oven. The oven all-in-one machine can not only perform steam cooking or baking operations separately, but also combines the two functions to achieve steam and oven hybrid cooking, resulting in a more rich taste of food while preserving nutrients and moisture.

[0003] The shell material of the oven all-in-one machine is diverse, and common materials include ceramics or enamel, which are relatively high in cost. If plastic materials are used, the heat resistance is relatively poor, and deformation, scratching or cracking is likely to occur. For flame-retardant PBT materials, the flame spread speed can be significantly reduced during combustion, and even self-extinguish under certain conditions. However, due to the REACH directive's restriction on PFAS (perfluoro or polyfluoroalkyl substances), the flame-retardant anti-dripping agent PTFE component needs to be removed from the material, which will directly affect the flame-retardant effect of the material. Antimony flame retardants can cause skin irritation in humans, and the cost of antimony flame retardants is also high, which is not suitable for the shell of the oven all-in-one machine. Non-antimony flame-retardant materials further affect the flame-retardant effect of the material. In addition, the shell structure of the oven all-in-one machine is complex, and the material flow requirements are extremely high, while also needing to meet the requirements of low warping, high-temperature baking resistance, and high-temperature and high-humidity resistance. SUMMARY

[0004] In order to overcome the shortcomings and deficiencies in the prior art, one of the purposes of the present application is to provide a reinforced flame-retardant polyester composite material for an oven all-in-one machine shell.

[0005] The second purpose of the present application is to provide a preparation method of a reinforced flame-retardant polyester composite material for an oven all-in-one machine shell. The preparation method is simple to operate, convenient to control, high in production efficiency, low in production cost, and can be used for large-scale production.

[0006] One of the purposes of the present application is achieved by the following technical solution: a reinforced flame-retardant polyester composite material for an oven all-in-one machine shell, comprising the following raw materials by weight:

[0007]

[0008] The baking all-in-one machine shell uses reinforced flame-retardant polyester composite material, taking polybutylene terephthalate and poly-1,4-cyclohexane dimethanol terephthalate as main raw materials, which has high insulation resistance, low dielectric constant and dielectric loss, can effectively block leakage current, avoid the risk of electric shock, ensure the safe operation of the circuit, in addition, the two can obtain high heat distortion temperature, heat resistance and high strength, polybutylene terephthalate has good fatigue resistance and dimensional stability, and small creep; the special grafted modified thermoplastic polyester elastomer is added, which utilizes the special heat-sensitive hydrophobicity and the toughening property of the thermoplastic polyester elastomer, and cooperates with the toughening agent and the antioxidant to improve the hydrolysis resistance, high temperature and high humidity weather resistance, high and low temperature impact toughness and low shrinkage of the polyester composite material; the added bromine-based flame retardant and halogen-free flame retardant provide gas source cooling, and the halogen-free flame retardant mainly has the effect of forming carbon, and the carbon layer network structure formed on the surface is not easy to drop, and at the same time, oxygen and material combustion are isolated, the two cooperate to block fire, can meet the flame-retardant requirements of the material, and can achieve PFAS-free and lower cost; the added special glass fiber has the effects of hydrolysis resistance and low warping, and low shrinkage can promote the structure of the product to be flat, and is especially suitable for producing baking all-in-one machine shell.

[0009] Preferably, the intrinsic viscosity of the polybutylene terephthalate is 0.7-1.2 dL / g, and the intrinsic viscosity of the poly-1,4-cyclohexane dimethanol terephthalate is 0.7-1.2 dL / g.

[0010] Preferably, the preparation method of each part of the grafted modified thermoplastic polyester elastomer comprises the following steps:

[0011] (R1), taking 100 parts of organic solvent, 25-45 parts of thermoplastic polyester elastomer TPEE, 3-8 parts of N-isopropyl acrylamide monomer, 3-4 parts of initiator solution and 50 parts of methanol by weight, standby;

[0012] (R2), adding thermoplastic polyester elastomer TPEE and N-isopropyl acrylamide monomer to the organic solvent, heating to 60-70 DEG C and stirring to dissolve, to obtain a mixed solution;

[0013] (R3), the mixed solution is heated to 75-85 DEG C, and the initiator solution is continuously added while stirring for 1-2 h, and then stirring is continued for 2-5 h, and then the reaction semi-product is obtained after cooling;

[0014] (R4), after mixing, filtering, washing and drying treatment, the grafted modified thermoplastic polyester elastomer is obtained.

[0015] In the technical solution, the thermoplastic polyester elastomer TPEE and N-isopropyl acrylamide monomers are reacted under the action of an initiator and heating in an organic solvent to obtain TPEE grafted with N-isopropyl acrylamide, which has the functions of compatibility, toughening and low warping. N-isopropyl acrylamide has a hydrophilic amide group and a hydrophobic isopropyl group in the molecule, and the reaction conditions are relatively flexible, and the requirements for the solvent and the acid-base degree are not high. There is no side reaction such as anhydride hydrolysis to affect the grafting efficiency and the performance of the product. The grafted material has temperature sensitivity, and cooperates with the toughening agent and the antioxidant to improve the hydrolysis resistance, high-temperature and high-humidity weather resistance, high and low temperature impact toughness and low shrinkage of the polyester composite material.

[0016] Preferably, the organic solvent is N,N-dimethylformamide, the Shore D hardness of the thermoplastic polyester elastomer TPEE is 40±5, and the initiator solution is an azo initiator-N,N-dimethylformamide solution with a concentration of 2-5wt%.

[0017] Preferably, the toughening agent is at least one of ethylene-octene copolymer grafted glycidyl methacrylate (POE-g-GMA), ethylene-acrylate-glycidyl methacrylate terpolymer, ethylene-butyl acrylate copolymer (EBA), and ethylene-methyl acrylate copolymer (EMA).

[0018] Preferably, the antioxidant is antioxidant S9228, and the ester exchange inhibitor is dihydrogen disodium pyrophosphate.

[0019] In the technical solution, the antioxidant S9228 has good antioxidant effect at high temperature and is not easily hydrolyzed in a high-humidity state. The antioxidant S9228 cooperates with the specially grafted and modified thermoplastic polyester elastomer to improve the hydrolysis resistance and high-temperature and high-humidity weather resistance of the polyester composite material.

[0020] Preferably, the bromine-based flame retardant is at least one of brominated polystyrene, brominated polycarbon, brominated epoxy, and brominated triazine, and the halogen-free flame retardant is diisobutyl aluminum hypophosphite.

[0021] In the technical solution, the bromine-based flame retardant provides a gas source for cooling, and the halogen-free flame retardant mainly forms carbon, and a carbon layer network structure is formed on the surface to prevent dripping and isolate oxygen and the material from burning. The two flame retardants can meet the flame-retardant requirements of the material, are PFAS-free, and have lower cost. In addition, the melting point of diisobutyl aluminum hypophosphite is 250-280℃, which is lower than that of conventional organic aluminum hypophosphite, and the improvement of the flowability of the material is more obvious.

[0022] Preferably, the glass fiber is a hydrolysis-resistant flat glass fiber obtained by soaking flat glass fiber in a hydrolysis-resistant infiltrant for 5-10 hours and drying, the average flat ratio of the glass fiber is 1:3-5, the average length of the short-cut is 2-3 mm, and the average thickness of the single filament is 5-10 mm.

[0023] The above technical solution has the effects of hydrolysis resistance and low warping, and low shrinkage can promote the structure of the product to be flat, and is particularly suitable for producing an oven all-in-one machine shell.

[0024] Preferably, the hydrolysis-resistant infiltrant comprises the following raw materials by weight: 100 parts of polyester resin emulsion, 0.5-1 part of silane coupling agent, 1 part of sulfate, 2-3 parts of polycarbodiimide, and 1-5 parts of polyethylene wax.

[0025] The above technical solution uses polyester resin emulsion as the main body, and adds silane coupling agent, sulfate, polycarbodiimide, and polyethylene wax for blending to obtain the hydrolysis-resistant infiltrant. After the flat glass fiber is soaked, the hydrolysis-resistant infiltrant reacts with the functional groups such as hydroxyl groups on the surface of the glass fiber to form chemical bonds, thereby forming a continuous protective film on the surface of the glass fiber, enhancing the hydrolysis resistance of the fiber, improving the interfacial bonding strength between the glass fiber and the resin matrix, thereby enhancing the overall performance of the composite material, eliminating or weakening the static electricity on the surface of the fiber, ensuring the smooth progress of the production process, and reducing the friction between the fibers and improving the flowability of the fibers.

[0026] The second object of the present application is achieved by the following technical solution: the preparation method of the reinforced flame-retardant polyester composite material for the oven all-in-one machine shell as described above, comprising the following steps:

[0027] (S1), take polybutylene terephthalate, poly(1,4-cyclohexane dimethylene terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor, and glass fiber according to weight parts, for standby;

[0028] (S2), after the polybutylene terephthalate, poly(1,4-cyclohexane dimethylene terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor, and glass fiber are uniformly mixed, they are extruded and granulated through a double-screw extruder to obtain the reinforced flame-retardant polyester composite material for the oven all-in-one machine shell;

[0029] The processing temperatures of each section of the double-screw extruder are 200℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, respectively, the die temperature is 270-290℃, and the screw rotation speed is 500-600r / min.

[0030] The baking all-in-one machine shell reinforced flame-retardant polyester composite material of the present application uses polybutylene terephthalate and poly-1,4-cyclohexanedimethanol terephthalate as main raw materials, has high insulation resistance, low dielectric constant and dielectric loss, can effectively block leakage current, avoid the risk of electric shock, ensure the safe operation of the circuit, in addition, the two synergistically obtain high heat distortion temperature, heat resistance, high strength, polybutylene terephthalate has good fatigue resistance and dimensional stability, and small creep; the addition of special grafted thermoplastic polyester elastomer, the use of its special heat-sensitive hydrophobicity and the toughening property of thermoplastic polyester elastomer, and the synergistic effect of toughening agent and antioxidant, improve the hydrolysis resistance, high temperature and humidity weather resistance, high and low temperature impact toughness and low shrinkage of the polyester composite material; the addition of bromine-based flame retardant and halogen-free flame retardant, the bromine-based flame retardant provides gas source cooling, and the halogen-free flame retardant mainly has the effect of forming carbon, and the surface forms a carbon layer network structure which is not easy to drop, and at the same time, it isolates oxygen and combustion of the material, the two synergistically flame-retardant can meet the flame-retardant requirements of the material while achieving PFAS-free, and the cost is lower; the addition of special glass fiber plays a role in hydrolysis resistance and low warpage effect, and low shrinkage can promote the structure of the product to be flat, and is especially suitable for producing baking all-in-one machine shell.

[0031] The preparation method of the present application is simple to operate, convenient to control, high in production efficiency and low in production cost, and can be used for large-scale production. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of those skilled in the art, the present application will be further described below in conjunction with examples, and the content mentioned in the implementation manner is not a limitation on the present application.

[0033] Example 1

[0034] A kind of baking all-in-one machine shell reinforced flame-retardant polyester composite material, including the following weight parts of raw materials:

[0035]

[0036] The intrinsic viscosity of the polybutylene terephthalate is 0.8 dL / g, and the intrinsic viscosity of the poly-1,4-cyclohexanedimethanol terephthalate is 0.7 dL / g.

[0037] The preparation method of each part of the grafted thermoplastic polyester elastomer includes the following steps:

[0038] (R1), take 100 parts of organic solvent, 35 parts of thermoplastic polyester elastomer TPEE, 5 parts of N-isopropyl acrylamide monomer, 3.5 parts of initiator solution and 50 parts of methanol by weight, standby;

[0039] (R2), adding a thermoplastic polyester elastomer TPEE and N-isopropyl acrylamide monomer into an organic solvent, dissolving by heating and stirring at 65℃ to obtain a mixed solution;

[0040] (R3), heating the mixed solution to 80℃, adding an initiator solution dropwise while stirring for 1.5h, continuing to stir for 4h, and obtaining a reaction semi-product after cooling;

[0041] (R4), adding methanol to the reaction semi-product, and obtaining a graft-modified thermoplastic polyester elastomer after filtering, washing and drying.

[0042] The organic solvent is N,N-dimethylformamide, the Shore D hardness of the thermoplastic polyester elastomer TPEE is 40, and the initiator solution is an azobisisobutyronitrile-N,N-dimethylformamide solution with a concentration of 3wt%.

[0043] The toughening agent is ethylene-octene copolymer grafted glycidyl methacrylate (POE-g-GMA).

[0044] The antioxidant is antioxidant S9228, and the ester exchange inhibitor is dihydrogen sodium pyrophosphate.

[0045] The bromine-based flame retardant is brominated polystyrene, and the halogen-free flame retardant is aluminum diisobutyl phosphinate.

[0046] The glass fiber is hydrolysis-resistant flat glass fiber obtained by soaking flat glass fiber in a hydrolysis-resistant sizing agent for 8h and then drying, and the average flatness ratio of the glass fiber is 1:3.5, the average length of the chopped fiber is 3mm, and the average thickness of the single filament is 8mm.

[0047] The hydrolysis-resistant sizing agent comprises the following raw materials by weight: 100 parts of polyester resin emulsion PU7301, 0.8 parts of silane coupling agent KH570, 1 part of sulfate, 2.5 parts of polycarbodiimide, and 3 parts of polyethylene wax.

[0048] The preparation method of the reinforced flame-retardant polyester composite material for the roasting all-in-one machine shell comprises the following steps:

[0049] (S1), taking polybutylene terephthalate, polycyclohexane dimethanol terephthalate, graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor and glass fiber by weight parts, and reserving;

[0050] (S2), the polybutylene terephthalate, poly-1, 4-cyclohexane dimethylene terephthalate, graft modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine flame retardant, halogen-free flame retardant, ester exchange inhibitor and glass fiber are uniformly mixed, and then extruded and granulated by a double screw extruder to obtain the reinforced flame-retardant polyester composite material for the baking all-in-one machine shell;

[0051] The processing temperature of each section of the double screw extruder from the feeding section is 200 DEG C, 270 DEG C, 280 DEG C, 270 DEG C, 270 DEG C, 280 DEG C, 280 DEG C, 260 DEG C, 270 DEG C, 270 DEG C respectively, the die head temperature is 290 DEG C, and the screw rotation speed is 500 r / min.

[0052] Example 2

[0053] A reinforced flame-retardant polyester composite material for the baking all-in-one machine shell comprises the following raw materials by weight:

[0054]

[0055] The intrinsic viscosity of the polybutylene terephthalate is 0.8 dL / g, and the intrinsic viscosity of the poly-1, 4-cyclohexane dimethylene terephthalate is 0.7 dL / g.

[0056] The preparation method of each part of the graft modified thermoplastic polyester elastomer comprises the following steps:

[0057] (R1), 100 parts of an organic solvent, 25 parts of a thermoplastic polyester elastomer TPEE, 3 parts of N-isopropyl acrylamide monomer, 3 parts of an initiator solution and 50 parts of methanol are taken by weight for standby;

[0058] (R2), the thermoplastic polyester elastomer TPEE and the N-isopropyl acrylamide monomer are added to the organic solvent, heated to 60 DEG C and stirred to dissolve, to obtain a mixed solution;

[0059] (R3), the mixed solution is heated to 75 DEG C, the initiator solution is continuously added dropwise while stirring for 1 h, and then stirring is continued for 2 h, and the reaction semi-finished product is obtained after cooling;

[0060] (R4), methanol is added to the reaction semi-finished product and mixed, and then filtered, washed and dried to obtain the graft modified thermoplastic polyester elastomer.

[0061] The organic solvent is N,N-dimethylformamide, the Shore D hardness of the thermoplastic polyester elastomer TPEE is 40, and the initiator solution is an azobisisobutyronitrile-N,N-dimethylformamide solution with a concentration of 3wt%.

[0062] The toughening agent is ethylene-octene copolymer grafted glycidyl methacrylate (POE-g-GMA).

[0063] The antioxidant is antioxidant S9228; the ester exchange inhibitor is dihydrogen sodium pyrophosphate.

[0064] The bromine-based flame retardant is brominated polystyrene; the halogen-free flame retardant is aluminum diisobutyl phosphinate.

[0065] The glass fiber is hydrolysis-resistant flat glass fiber obtained by soaking flat glass fiber in a hydrolysis-resistant sizing agent for 5h and then drying, wherein the average flatness ratio of the glass fiber is 1:3, the average length of the chopped fiber is 2mm, and the average thickness of the single filament is 5mm.

[0066] The hydrolysis-resistant sizing agent comprises the following raw materials by weight: 100 parts of polyester resin emulsion PU7301, 1 part of silane coupling agent KH570, 1 part of sulfate, 3 parts of polycarbodiimide, and 5 parts of polyethylene wax.

[0067] The preparation method of the reinforced flame-retardant polyester composite material for the roasting all-in-one machine shell comprises the following steps:

[0068] (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethylene terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor, and glass fiber by weight parts, for standby;

[0069] (S2), uniformly mixing polybutylene terephthalate, poly(1,4-cyclohexanedimethylene terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor, and glass fiber, and then extruding and granulating through a double-screw extruder to obtain a reinforced flame-retardant polyester composite material for the roasting all-in-one machine shell;

[0070] Wherein, the processing temperature of each section of the double-screw extruder from the feeding section is respectively: 200℃, 270℃, 280℃, 270℃, 270℃, 280℃, 280℃, 260℃, 270℃, 270℃, the die temperature is 290℃, and the screw rotation speed is 500r / min.

[0071] Example 3

[0072] A reinforced flame-retardant polyester composite material for the roasting all-in-one machine shell comprises the following raw materials by weight:

[0073]

[0074] The intrinsic viscosity of the polybutylene terephthalate is 0.8 dL / g, and the intrinsic viscosity of the poly-1,4-cyclohexanedimethylene terephthalate is 0.7 dL / g.

[0075] The preparation method of each part of the graft-modified thermoplastic polyester elastomer comprises the following steps:

[0076] (R1), taking 100 parts of an organic solvent, 45 parts of a thermoplastic polyester elastomer TPEE, 8 parts of an N-isopropyl acrylamide monomer, 4 parts of an initiator solution, and 50 parts of methanol by weight parts, standby;

[0077] (R2), adding the thermoplastic polyester elastomer TPEE and the N-isopropyl acrylamide monomer into the organic solvent, heating to 70°C and stirring to dissolve to obtain a mixed solution;

[0078] (R3), heating the mixed solution to 85°C, continuously adding the initiator solution dropwise while stirring for 2h, and continuing to stir for 5h, and then cooling to obtain a reaction semi-finished product;

[0079] (R4), adding methanol to the reaction semi-finished product, and then filtering, washing, and drying to obtain a graft-modified thermoplastic polyester elastomer.

[0080] The organic solvent is N,N-dimethylformamide, the Shore D hardness of the thermoplastic polyester elastomer TPEE is 40, and the initiator solution is an azobisisobutyronitrile-N,N-dimethylformamide solution with a concentration of 3wt%.

[0081] The toughening agent is ethylene-octene copolymer grafted glycidyl methacrylate (POE-g-GMA).

[0082] The antioxidant is antioxidant S9228; and the ester exchange inhibitor is dihydrogen sodium pyrophosphate.

[0083] The bromine-based flame retardant is brominated polystyrene; and the halogen-free flame retardant is aluminum diisobutyl phosphinate.

[0084] The glass fiber is a hydrolysis-resistant flat glass fiber obtained by soaking flat glass fiber in a hydrolysis-resistant sizing agent for 10h and then drying, and the average flatness ratio of the glass fiber is 1:5, the average length of the chopped fiber is 3mm, and the average thickness of the single filament is 10mm.

[0085] The hydrolysis-resistant sizing agent comprises the following raw materials by weight parts: 100 parts of polyester resin emulsion PU7301, 0.5 parts of silane coupling agent KH570, 1 part of sulfate, 2 parts of polycarbodiimide, and 1 part of polyethylene wax.

[0086] The preparation method of the reinforced flame-retardant polyester composite material for the roasting all-in-one machine shell comprises the following steps:

[0087] (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethylene terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor and glass fiber by weight parts, standby;

[0088] (S2), polybutylene terephthalate, poly(1,4-cyclohexanedimethylene terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor and glass fiber are mixed uniformly, then extruded and granulated by a twin-screw extruder to obtain a reinforced flame-retardant polyester composite material for a baking all-in-one machine shell;

[0089] Wherein, the processing temperature of each section of the twin-screw extruder from the feeding section is respectively: 200℃, 270℃, 280℃, 270℃, 270℃, 280℃, 280℃, 260℃, 270℃, 270℃, the die temperature is 290℃, and the screw speed is 500r / min.

[0090] Example 4

[0091] A reinforced flame-retardant polyester composite material for a baking all-in-one machine shell, comprising the following raw materials by weight parts:

[0092]

[0093]

[0094] The intrinsic viscosity of the polybutylene terephthalate is 0.8dL / g, and the intrinsic viscosity of the poly(1,4-cyclohexanedimethylene terephthalate) is 0.7dL / g.

[0095] The preparation method of each part of the graft-modified thermoplastic polyester elastomer comprises the following steps:

[0096] (R1), taking 100 parts of organic solvent, 30 parts of thermoplastic polyester elastomer TPEE, 5 parts of N-isopropyl acrylamide monomer, 3 parts of initiator solution and 50 parts of methanol by weight parts, standby;

[0097] (R2), adding thermoplastic polyester elastomer TPEE and N-isopropyl acrylamide monomer to the organic solvent, heating to 60℃ and stirring to dissolve to obtain a mixed solution;

[0098] (R3), the mixed solution is heated to 85℃, the initiator solution is added dropwise while stirring for 1.2h, and then stirring is continued for 2.5h, and the reaction semi-finished product is obtained after cooling;

[0099] (R4), methanol is added to the reaction semi-finished product, and after mixing, filtration, washing and drying treatment, a graft-modified thermoplastic polyester elastomer is obtained.

[0100] The organic solvent is N,N-dimethylformamide, the Shore D hardness of the thermoplastic polyester elastomer TPEE is 40, and the initiator solution is an azobisisobutyronitrile-N,N-dimethylformamide solution with a concentration of 3wt%.

[0101] The toughening agent is ethylene-octene copolymer grafted glycidyl methacrylate (POE-g-GMA).

[0102] The antioxidant is antioxidant S9228, and the ester exchange inhibitor is dihydrogen sodium pyrophosphate.

[0103] The bromine-based flame retardant is brominated polystyrene, and the halogen-free flame retardant is aluminum diisobutyl phosphinate.

[0104] The glass fiber is hydrolysis-resistant flat glass fiber obtained by soaking flat glass fiber in a hydrolysis-resistant sizing agent for 8 hours and then drying, and has an average flat ratio of 1:4, an average short-cut length of 2mm, and an average single-filament thickness of 6mm.

[0105] The hydrolysis-resistant sizing agent comprises the following raw materials by weight: 100 parts of polyester resin emulsion PU7301, 0.8 parts of silane coupling agent KH570, 1 part of sulfate, 2.3 parts of polycarbodiimide, and 2 parts of polyethylene wax.

[0106] The preparation method of the reinforced flame-retardant polyester composite material for the roasting all-in-one machine shell comprises the following steps:

[0107] (S1), taking polybutylene terephthalate, polycyclohexane dimethanol terephthalate, graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor and glass fiber by weight parts, for standby;

[0108] (S2), after mixing polybutylene terephthalate, polycyclohexane dimethanol terephthalate, graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, bromine-based flame retardant, halogen-free flame retardant, ester exchange inhibitor and glass fiber uniformly, extruding and granulating through a double-screw extruder to obtain a reinforced flame-retardant polyester composite material for the roasting all-in-one machine shell;

[0109] The processing temperatures of each section of the double-screw extruder, starting from the feeding section, are 200℃, 270℃, 280℃, 270℃, 270℃, 280℃, 280℃, 260℃, 270℃, 270℃, respectively, the die temperature is 290℃, and the screw rotation speed is 500r / min.

[0110] Comparative Example 1

[0111] The difference between the present comparative example and Example 1 is that:

[0112] The graft-modified thermoplastic polyester elastomer is replaced by TPEE-g-MAH, and the grafting rate of maleic anhydride is 0.22%.

[0113] Comparative Example 2

[0114] The difference between the present comparative example and Example 1 is that:

[0115] The hydrolysis-resistant wetting agent is a polyester resin emulsion PU7301.

[0116] Comparative Example 3

[0117] The difference between the present comparative example and Example 1 is that:

[0118] The halogen-free flame retardant is aluminum diethyl phosphinate.

[0119] Performance test

[0120] The polyester composite materials of Examples 1-4 and Comparative Examples 1-3 are taken to test their shrinkage, tensile strength, bending strength, impact strength, heat distortion temperature, flame retardancy, and double 85 aging test, and the test results are as follows

[0121] As shown in Table 1:

[0122]

[0123]

[0124] As can be seen from the above Table 1, the reinforced flame-retardant polyester composite material for the baking machine shell has a high heat distortion temperature, high strength, hydrolysis resistance, high temperature and humidity resistance, high and low temperature impact toughness, flame retardancy and low shrinkage, and is particularly suitable for producing baking machine shells.

[0125] The above examples are the preferred implementation of the present application, in addition to this, the present application can be realized in other ways, without departing from the concept of the present application, any obvious replacement within the protection scope of the present application.

Claims

1. A reinforced flame-retardant polyester composite material for the outer shell of an integrated baking machine, characterized in that, The ingredients include the following parts by weight: 20-60 parts of polybutylene terephthalate 20-60 parts of polyethylene terephthalate (PET) 10-30 parts of graft-modified thermoplastic polyester elastomer 2-6 parts toughening agent Antioxidant 0.2-0.4 parts 10-20 parts of brominated flame retardant 10-20 parts of halogen-free flame retardant Transesterification inhibitor 0.5-1 part 10-30 parts glass fiber; The preparation method of the grafted modified thermoplastic polyester elastomer includes the following steps: (R1) Take 100 parts by weight of organic solvent, 25-45 parts of thermoplastic polyester elastomer TPEE, 3-8 parts of N-isopropylacrylamide monomer, 3-4 parts of initiator solution and 50 parts of methanol, and set aside. (R2) Add thermoplastic polyester elastomer TPEE and N-isopropylacrylamide monomer to an organic solvent, heat to 60-70℃ and stir to dissolve to obtain a mixed solution; (R3) Heat the mixed solution to 75-85°C, and add the initiator solution dropwise while stirring for 1-2 hours. Continue stirring for 2-5 hours, and then cool to obtain the reaction semi-finished product. (R4) After adding methanol to the reaction semi-finished product and mixing, the mixture is filtered, washed and dried to obtain grafted modified thermoplastic polyester elastomer. The brominated flame retardant is at least one of brominated polystyrene, brominated polycarbonate, brominated epoxy, and brominated triazine; the halogen-free flame retardant is aluminum diisobutylphosphite. The glass fiber is obtained by soaking flat glass fiber in a hydrolysis-resistant wetting agent for 5-10 hours and then drying it. The hydrolysis-resistant wetting agent comprises the following raw materials in parts by weight: 100 parts polyester resin emulsion, 0.5-1 parts silane coupling agent, 1 part sulfate ester, 2-3 parts polycarbodiimide and 1-5 parts polyethylene wax; The organic solvent is N,N-dimethylformamide.

2. The reinforced flame-retardant polyester composite material for the outer shell of an integrated baking machine according to claim 1, characterized in that: The intrinsic viscosity of the polybutylene terephthalate is 0.7-1.2 dL / g, and the intrinsic viscosity of the poly(1,4-cyclohexanediethanol terephthalate) is 0.7-1.2 dL / g.

3. The reinforced flame-retardant polyester composite material for the outer shell of an integrated baking machine according to claim 1, characterized in that: The thermoplastic polyester elastomer TPEE has a Shore D hardness of 40±5, and the initiator solution is an N,N-dimethylformamide solution of an azo initiator with a concentration of 2-5wt%.

4. The reinforced flame-retardant polyester composite material for the outer shell of an integrated baking machine according to claim 1, characterized in that: The toughening agent is at least one of ethylene-octene copolymer grafted glycidyl methacrylate (POE-g-GMA), ethylene-acrylate-glycidyl methacrylate terpolymer, ethylene-butyl acrylate copolymer (EBA), and ethylene-methyl acrylate copolymer (EMA).

5. The reinforced flame-retardant polyester composite material for the outer shell of an integrated baking machine according to claim 1, characterized in that: The antioxidant is antioxidant S9228; the transesterification inhibitor is disodium dihydrogen pyrophosphate.

6. A method for preparing a reinforced flame-retardant polyester composite material for the shell of a baking integrated machine as described in any one of claims 1-5, characterized in that, Includes the following steps: (S1) Take polybutylene terephthalate, poly(1,4-cyclohexanedimethyl terephthalate), grafted modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber according to the weight parts, and set aside. (S2) Polybutylene terephthalate, poly(1,4-cyclohexanedimethyl terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber are mixed evenly and then extruded and granulated by a twin-screw extruder to obtain a reinforced flame-retardant polyester composite material for the shell of the baking integrated machine. The processing temperatures of the twin-screw extruder from the feeding section onwards are as follows: 200℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, the die head temperature is 270-290℃, and the screw speed is 500-600 r / min.

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