Reinforced flame-retardant polyester composite material for baking all-in-one machine shell and preparation method of reinforced flame-retardant polyester composite material

Abstract

The invention relates to the technical field of polyester composite materials, in particular to a reinforced flame-retardant polyester composite material for a baking all-in-one machine shell and a preparation method of the reinforced flame-retardant polyester composite material for the baking all-in-one machine shell. The polybutylene terephthalate and the polybutylene terephthalate cooperate to obtain higher heat deformation temperature, heat resistance and high strength, and the polybutylene terephthalate has better fatigue resistance and dimensional stability and smaller creep deformation; the graft modified thermoplastic polyester elastomer is added, the special thermosensitive hydrophobicity of the graft modified thermoplastic polyester elastomer and the toughening property of the thermoplastic polyester elastomer are utilized, and the graft modified thermoplastic polyester elastomer, the toughening agent and the antioxidant have a synergistic effect, so that the hydrolysis resistance, the high-temperature and high-humidity resistance, the weather resistance, the high-low temperature impact toughness and the low shrinkage rate of the polyester composite material are improved; the added brominated flame retardant and halogen-free flame retardant have a synergistic flame retardant effect, so that the flame retardant requirement of the material can be met; the glass fibers have hydrolysis-resistant and low-warping effects, low shrinkage can promote the structure flatness of the product, and the glass fibers are particularly suitable for producing the baking all-in-one machine shell.

Description

Technical Field

[0001] The invention relates to the technical field of polyester composite materials, and in particular to a reinforced flame-retardant polyester composite material for a baking machine housing and a preparation method thereof. Background Art

[0002] A combined oven and steamer, also commonly known as a combined oven and steamer, is a kitchen appliance that combines the functions of a steamer and an oven. A combined oven and steamer can not only steam or bake separately, but also combine the two to achieve a hybrid of steaming and baking, making the food taste richer while retaining nutrition and moisture.

[0003] The shell materials of all-in-one ovens are varied, including ceramic or enamel materials, which are relatively expensive. If plastic materials are used, the heat resistance is relatively poor, it is easy to deform, and it is easy to scratch or crack. For flame-retardant PBT materials, the flame spread rate can be significantly reduced when burning, and it can even self-extinguish under certain conditions. However, due to the restrictions on PFAS (perfluoro or polyfluoroalkyl substances) in the REACH directive, it is necessary to remove the flame retardant and anti-drip agent PTFE in the material, which will directly affect the flame retardant effect of the material. Antimony flame retardants are easy to cause human skin allergies, and the cost of antimony flame retardants is also high. It is not suitable for the shell of all-in-one ovens. The absence of antimony flame retardants also further affects the flame retardant effect of the material. In addition, the shell structure of the all-in-one oven is relatively complex, and the material flow requirements are extremely high. At the same time, it needs to meet the requirements of low warping, high temperature baking resistance, and high temperature and high humidity resistance. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, one of the objectives of the present invention is to provide a reinforced flame-retardant polyester composite material for the shell of a toaster.

[0005] The second object of the present invention is to provide a method for preparing a reinforced flame-retardant polyester composite material for a toaster shell. The preparation method is simple to operate, convenient to control, has high production efficiency, low production cost, and can be used for large-scale production.

[0006] One of the purposes of the present invention is achieved through the following technical solution: A reinforced flame-retardant polyester composite material for a baking machine housing comprises the following raw materials in parts by weight:

[0007]

[0008] The shell of the baking machine is made of reinforced flame-retardant polyester composite material, with polybutylene terephthalate and poly(1,4-cyclohexanedimethanol terephthalate) as the 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, and ensure the safe operation of the circuit. In addition, the two work together to obtain high heat deformation temperature, heat resistance, and high strength. Polybutylene terephthalate has good fatigue resistance and dimensional stability, and small creep; special grafted modified thermoplastic polyester elastomer is added, and its special thermosensitive hydrophobicity and the toughening of thermoplastic polyester elastomer are utilized to The toughening agent and antioxidant work synergistically to improve the hydrolysis resistance, high temperature and high humidity weather resistance, high and low temperature impact toughness and low shrinkage of polyester composite materials; the added brominated flame retardants and halogen-free flame retardants, the brominated flame retardants provide gas source cooling, the main effect of the halogen-free flame retardant is charring, and the carbon layer network structure formed on the surface is not easy to drip, and at the same time isolates oxygen from the combustion of the material. The synergistic flame retardancy of the two can meet the flame retardant requirements of the material while being PFAS-free and at a lower cost; the added special glass fiber has the effects of hydrolysis resistance and low warping, and the low shrinkage can promote the flatness of the product structure, which is particularly suitable for the production of baking-in-one machine casings.

[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-cyclohexanedimethanol terephthalate) is 0.7-1.2 dL / g.

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

[0011] (R1), take 100 parts 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 by weight, and set aside;

[0012] (R2), adding thermoplastic polyester elastomer TPEE and N-isopropylacrylamide monomer to an organic solvent, heating to 60-70° C. and stirring to dissolve, to obtain a mixed solution;

[0013] (R3), heating the mixed solution to 75-85° C., adding the initiator solution dropwise for 1-2 hours while stirring, continuing to stir for 2-5 hours, and cooling to obtain a reaction semi-finished product;

[0014] (R4), adding methanol to the semi-finished product, mixing, filtering, washing and drying to obtain a graft-modified thermoplastic polyester elastomer.

[0015] By adopting the above technical scheme, the thermoplastic polyester elastomer TPEE and N-isopropylacrylamide monomer react in an organic solvent under the action of an initiator and heating to obtain TPEE grafted N-isopropylacrylamide, which has the functions of compatibility, toughening and low warping. Due to the hydrophilic amide group and hydrophobic isopropyl group in the molecule of N-isopropylacrylamide, the reaction conditions are relatively flexible and the requirements on solvent and pH are not large. There is no side reaction such as acid anhydride hydrolysis that affects the grafting efficiency and product performance. The stability is good. The grafted material is temperature-sensitive and synergistic with the toughening agent and 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%. Further, the azo initiator is azobisisobutyronitrile and / or azobisisoheptanenitrile.

[0017] Preferably, the toughening agent is at least one of ethylene-octene copolymer grafted with 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 transesterification inhibitor is disodium dihydrogen pyrophosphate.

[0019] By adopting the above technical scheme, the antioxidant S9228 has a good antioxidant effect at high temperature and is not easily hydrolyzed under high humidity conditions. It works synergistically with the special grafted modified thermoplastic polyester elastomer to improve the hydrolysis resistance, high temperature and high humidity weather resistance of the polyester composite material.

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

[0021] With the above technical solution, the brominated flame retardant provides air source cooling, and the main effect of the halogen-free flame retardant is charring. The carbon layer mesh structure formed on the surface is not easy to drip, and at the same time isolates oxygen and material combustion. The synergistic flame retardancy of the two can meet the flame retardancy requirements of the material while being PFAS-free and at a lower cost. In addition, the melting point of diisobutyl aluminum hypophosphite is 250-280℃, which is lower than the melting point of conventional organic aluminum hypophosphite, and has a more obvious beneficial effect on improving the fluidity of the material.

[0022] Preferably, the glass fiber is a hydrolysis-resistant flat glass fiber obtained by soaking flat glass fiber in a hydrolysis-resistant impregnating agent for 5-10 hours and then drying, and the average flatness ratio of the glass fiber is 1:3-5, the average short chopped length is 2-3 mm, and the average thickness of the monofilament is 5-10 mm.

[0023] The above technical solution achieves hydrolysis resistance and low warping effects, and the low shrinkage can promote the flatness of the product structure, which is particularly suitable for the production of the shell of the all-in-one baking machine.

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

[0025] By adopting the above technical scheme, polyester resin emulsion is used as the main body, and silane coupling agent, sulfate, polycarbodiimide and polyethylene wax are added to blend to obtain a hydrolysis-resistant wetting agent. After the flat glass fiber is immersed, the hydrolysis-resistant wetting agent reacts with functional groups such as hydroxyl groups on the surface of the glass fiber to form chemical bonds, forming a continuous protective film on the surface of the glass fiber, enhancing the hydrolysis resistance of the fiber, and improving the interface 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 fiber surface, ensuring the smooth progress of the production process, and reducing the friction between the fibers and improving the fluidity of the fibers.

[0026] The second object of the present invention is achieved by the following technical solution: The preparation method of the above-mentioned reinforced flame-retardant polyester composite material for the shell of the integrated toaster comprises the following steps:

[0027] (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber according to weight parts, and setting aside;

[0028] (S2), polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber are uniformly mixed, 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 machine;

[0029] Among them, the processing temperatures of each section of the twin-screw extruder starting from the feeding section are: 200℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, the head temperature is 270-290℃, and the screw speed is 500-600r / min.

[0030] The beneficial effects of the present invention are as follows: the reinforced flame-retardant polyester composite material for the shell of the all-in-one baking machine of the present invention 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, and ensure the safe operation of the circuit. In addition, the two synergistically obtain high heat deformation temperature, heat resistance, and high strength. Polybutylene terephthalate has good fatigue resistance and dimensional stability, and small creep. A special graft-modified thermoplastic polyester elastomer is added, and its special heat-sensitive hydrophobicity and thermoplastic polyester elastomer are utilized. The toughening of the body, synergistically with toughening agents and antioxidants, improves the hydrolysis resistance, high temperature and high humidity weather resistance, high and low temperature impact toughness and low shrinkage of polyester composite materials; the added brominated flame retardants and halogen-free flame retardants, the brominated flame retardants provide gas source cooling, the main effect of the halogen-free flame retardant is charring, and a carbon layer network structure is formed on the surface that is not easy to drip, while isolating oxygen from the combustion of the material. The synergistic flame retardancy of the two can meet the flame retardant requirements of the material while being PFAS-free and at a lower cost; the added special glass fiber has the effect of hydrolysis resistance and low warping, and the low shrinkage can promote the flatness of the product structure, which is particularly suitable for the production of baking-in-one machine shells.

[0031] The preparation method of the invention has the advantages of simple operation, convenient control, high production efficiency and low 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 invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0033] Example 1

[0034] A reinforced flame-retardant polyester composite material for a baking machine housing comprises the following raw materials in parts by weight:

[0035]

[0036] 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.

[0037] The preparation method of each graft-modified thermoplastic polyester elastomer comprises 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, and set aside;

[0039] (R2), adding thermoplastic polyester elastomer TPEE and N-isopropylacrylamide monomer to an organic solvent, heating to 65° C. and stirring to dissolve, to obtain a mixed solution;

[0040] (R3), heating the mixed solution to 80° C., adding the initiator solution dropwise for 1.5 h while stirring, continuing to stir for 4 h, and cooling to obtain a reaction semi-finished product;

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

[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 a 3wt% azobisisobutyronitrile-N,N-dimethylformamide solution.

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

[0044] The antioxidant is antioxidant S9228; the ester exchange inhibitor is disodium dihydrogen pyrophosphate.

[0045] The brominated flame retardant is brominated polystyrene; and the halogen-free flame retardant is diisobutyl aluminum hypophosphite.

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

[0047] The hydrolysis-resistant wetting agent comprises the following raw materials in parts 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 method for preparing the reinforced flame-retardant polyester composite material for the shell of the baking machine comprises the following steps:

[0049] (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber according to weight parts, and setting aside;

[0050] (S2), polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber are uniformly mixed, 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 machine;

[0051] Among them, the processing temperatures of each section of the twin-screw extruder starting from the feeding section are: 200℃, 270℃, 280℃, 270℃, 270℃, 280℃, 280℃, 260℃, 270℃, 270℃, 270℃, the head temperature is 290℃, and the screw speed is 500r / min.

[0052] Example 2

[0053] A reinforced flame-retardant polyester composite material for a baking machine housing comprises the following raw materials in parts 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-cyclohexanedimethylene terephthalate) is 0.7 dL / g.

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

[0057] (R1), take 100 parts of organic solvent, 25 parts of thermoplastic polyester elastomer TPEE, 3 parts of N-isopropylacrylamide monomer, 3 parts of initiator solution and 50 parts of methanol by weight, and set aside;

[0058] (R2), adding thermoplastic polyester elastomer TPEE and N-isopropylacrylamide monomer to an organic solvent, heating to 60° C. and stirring to dissolve, to obtain a mixed solution;

[0059] (R3), heating the mixed solution to 75° C., adding the initiator solution dropwise for 1 h while stirring, continuing to stir for 2 h, and cooling to obtain a reaction semi-finished product;

[0060] (R4), adding methanol to the semi-finished product, mixing, filtering, washing and drying to obtain a 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 a 3wt% azobisisobutyronitrile-N,N-dimethylformamide solution.

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

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

[0064] The brominated flame retardant is brominated polystyrene; and the halogen-free flame retardant is diisobutyl aluminum hypophosphite.

[0065] The glass fiber is a hydrolysis-resistant flat glass fiber obtained by soaking the flat glass fiber in a hydrolysis-resistant impregnating agent for 5 hours and then drying it. The glass fiber has an average flatness ratio of 1:3, an average short chopped length of 2 mm, and an average monofilament thickness of 5 mm.

[0066] The hydrolysis-resistant wetting agent comprises the following raw materials in parts 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 method for preparing the reinforced flame-retardant polyester composite material for the shell of the baking machine comprises the following steps:

[0068] (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber according to weight parts, and setting aside;

[0069] (S2), polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber are uniformly mixed, 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 machine;

[0070] Among them, the processing temperatures of each section of the twin-screw extruder starting from the feeding section are: 200℃, 270℃, 280℃, 270℃, 270℃, 280℃, 280℃, 260℃, 270℃, 270℃, 270℃, the head temperature is 290℃, and the screw speed is 500r / min.

[0071] Example 3

[0072] A reinforced flame-retardant polyester composite material for a baking machine housing comprises the following raw materials in parts 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 graft-modified thermoplastic polyester elastomer comprises the following steps:

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

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

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

[0079] (R4), adding methanol to the semi-finished product, mixing, 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 a 3wt% azobisisobutyronitrile-N,N-dimethylformamide solution.

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

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

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

[0084] The glass fiber is a hydrolysis-resistant flat glass fiber obtained by soaking the flat glass fiber in a hydrolysis-resistant impregnating agent for 10 hours and then drying it. The glass fiber has an average flatness ratio of 1:5, an average short chopped length of 3 mm, and an average monofilament thickness of 10 mm.

[0085] The hydrolysis-resistant wetting agent comprises the following raw materials in parts by weight: 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 method for preparing the reinforced flame-retardant polyester composite material for the shell of the baking machine comprises the following steps:

[0087] (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber according to weight parts, and setting aside;

[0088] (S2), polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber are uniformly mixed, 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 machine;

[0089] Among them, the processing temperatures of each section of the twin-screw extruder starting from the feeding section are: 200℃, 270℃, 280℃, 270℃, 270℃, 280℃, 280℃, 260℃, 270℃, 270℃, 270℃, the head temperature is 290℃, and the screw speed is 500r / min.

[0090] Example 4

[0091] A reinforced flame-retardant polyester composite material for a baking machine housing comprises the following raw materials in parts by weight:

[0092]

[0093]

[0094] 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.

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

[0096] (R1), take 100 parts of organic solvent, 30 parts of thermoplastic polyester elastomer TPEE, 5 parts of N-isopropylacrylamide monomer, 3 parts of initiator solution and 50 parts of methanol by weight, and set aside;

[0097] (R2), adding thermoplastic polyester elastomer TPEE and N-isopropylacrylamide monomer to an organic solvent, heating to 60° C. and stirring to dissolve, to obtain a mixed solution;

[0098] (R3), heating the mixed solution to 85° C., adding the initiator solution dropwise for 1.2 h while stirring, continuing to stir for 2.5 h, and cooling to obtain a reaction semi-finished product;

[0099] (R4), adding methanol to the semi-finished product, mixing, filtering, washing and drying to obtain a graft-modified thermoplastic polyester elastomer.

[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 a 3wt% azobisisobutyronitrile-N,N-dimethylformamide solution.

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

[0102] The antioxidant is antioxidant S9228; the ester exchange inhibitor is disodium dihydrogen pyrophosphate.

[0103] The brominated flame retardant is brominated polystyrene; and the halogen-free flame retardant is diisobutyl aluminum hypophosphite.

[0104] The glass fiber is a hydrolysis-resistant flat glass fiber obtained by soaking the flat glass fiber in a hydrolysis-resistant impregnating agent for 8 hours and then drying it. The glass fiber has an average flatness ratio of 1:4, an average short chopped length of 2 mm, and an average monofilament thickness of 6 mm.

[0105] The hydrolysis-resistant wetting agent comprises the following raw materials in parts 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 method for preparing the reinforced flame-retardant polyester composite material for the shell of the baking machine comprises the following steps:

[0107] (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber according to weight parts, and setting aside;

[0108] (S2), polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber are uniformly mixed, 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 machine;

[0109] Among them, the processing temperatures of each section of the twin-screw extruder starting from the feeding section are: 200℃, 270℃, 280℃, 270℃, 270℃, 280℃, 280℃, 260℃, 270℃, 270℃, 270℃, the head temperature is 290℃, and the screw speed is 500r / min.

[0110] Comparative Example 1

[0111] The difference between this comparative example and Example 1 is:

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

[0113] Comparative Example 2

[0114] The difference between this comparative example and Example 1 is:

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

[0116] Comparative Example 3

[0117] The difference between this comparative example and Example 1 is:

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

[0119] Performance Testing

[0120] The polyester composite materials of Examples 1-4 and Comparative Examples 1-3 were tested for shrinkage, tensile strength, flexural strength, impact strength, heat deformation temperature, flame retardancy, and double 85 aging test. The test results are as follows:

[0121] As shown in Table 1:

[0122]

[0123]

[0124] It can be seen from Table 1 above that the reinforced flame-retardant polyester composite material used for the shell of the baking machine has high heat deformation temperature, high strength, hydrolysis resistance, high temperature and high humidity weather resistance, high and low temperature impact toughness, flame retardancy and low shrinkage, and is particularly suitable for the production of the shell of the baking machine.

[0125] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A reinforced flame-retardant polyester composite material for a baking machine housing, characterized in that: The invention comprises the following raw materials in parts by weight:

2. The reinforced flame-retardant polyester composite material for the shell of a toaster 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-cyclohexanedimethylene terephthalate) is 0.7-1.2 dL / g.

3. The reinforced flame-retardant polyester composite material for the shell of a toaster according to claim 1, characterized in that: The preparation method of each graft-modified thermoplastic polyester elastomer comprises the following steps: (R1), take 100 parts 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 by weight, and set aside; (R2), adding thermoplastic polyester elastomer TPEE and N-isopropylacrylamide monomer to an organic solvent, heating to 60-70° C. and stirring to dissolve, to obtain a mixed solution; (R3), heating the mixed solution to 75-85° C., adding the initiator solution dropwise for 1-2 hours while stirring, continuing to stir for 2-5 hours, and cooling to obtain a reaction semi-finished product; (R4), adding methanol to the semi-finished product, mixing, filtering, washing and drying to obtain a graft-modified thermoplastic polyester elastomer.

4. The reinforced flame-retardant polyester composite material for the shell of a toaster according to claim 3, characterized in that: 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%.

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

6. The reinforced flame-retardant polyester composite material for the shell of a toaster according to claim 1, characterized in that: The antioxidant is antioxidant S9228; the ester exchange inhibitor is disodium dihydrogen pyrophosphate.

7. The reinforced flame-retardant polyester composite material for the shell of a toaster according to claim 1, characterized in that: The brominated flame retardant is at least one of brominated polystyrene, brominated polycarbonate, brominated epoxy and brominated triazine; and the halogen-free flame retardant is diisobutyl aluminum hypophosphite.

8. The reinforced flame-retardant polyester composite material for the shell of a toaster according to claim 1, characterized in that: The glass fiber is a hydrolysis-resistant flat glass fiber obtained by soaking the flat glass fiber in a hydrolysis-resistant impregnating agent for 5-10 hours and then drying it. The glass fiber has an average flatness ratio of 1:3-5, an average short chopped length of 2-3 mm, and an average monofilament thickness of 5-10 mm.

9. The reinforced flame-retardant polyester composite material for the shell of a toaster according to claim 7, characterized in that: The hydrolysis-resistant wetting agent comprises the following raw materials in parts by weight: 100 parts of polyester resin emulsion, 0.5-1 parts of silane coupling agent, 1 part of sulfate, 2-3 parts of polycarbodiimide and 1-5 parts of polyethylene wax.

10. A method for preparing the reinforced flame-retardant polyester composite material for the shell of a toaster according to any one of claims 1 to 9, characterized in that: The steps include: (S1), taking polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber according to weight parts, and setting aside; (S2), polybutylene terephthalate, poly(1,4-cyclohexanedimethanol terephthalate), graft-modified thermoplastic polyester elastomer, toughening agent, antioxidant, brominated flame retardant, halogen-free flame retardant, transesterification inhibitor and glass fiber are uniformly mixed, 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 machine; Among them, the processing temperatures of each section of the twin-screw extruder starting from the feeding section are: 200℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, 260-280℃, the head temperature is 270-290℃, and the screw speed is 500-600r / min.

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