Halogen-free flame-retardant thermoplastic polyester elastomer and preparation method thereof

Abstract

The invention provides a halogen-free flame-retardant thermoplastic polyester elastomer and a preparation method thereof. The halogen-free flame-retardant thermoplastic polyester elastomer is prepared from the following components in parts by weight: 100 parts of polyether ester type TPEE (Thermoplastic Polyester Ester Ester), 10 to 30 parts of polymeric phosphorus flame retardant, 0.3 to 0.8 part of anti-dripping agent, 0.2 to 0.6 part of thermal stability aid and 0.2 to 0.5 part of ultraviolet absorbent. According to the halogen-free flame-retardant thermoplastic polyester elastomer and the preparation method thereof, the specific composition of the halogen-free flame-retardant thermoplastic polyester elastomer is designed, and the polymeric phosphorus flame retardant is further used, so that the problems that the flame retardant is poor in compatibility and easy to separate out in polyether ester TPEE are solved, and the halogen-free flame-retardant thermoplastic polyester elastomer with relatively good flame retardance and relatively good mechanical properties is prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant polymer materials, and in particular relates to a halogen-free flame-retardant thermoplastic polyester elastomer and a preparation method thereof. Background Art

[0002] Thermoplastic polyester elastomer (TPEE) is an emerging block polyester thermoplastic elastomer. Its structure consists of two parts: polyester hard segment and polyether / aliphatic polyester soft segment. The polyester hard segment gives the material good processability and excellent mechanical properties, while the polyether / aliphatic polyester soft segment gives the material good resilience and low-temperature toughness, making it have both the processability of plastic materials and the elasticity of rubber materials, becoming an emerging popular elastomer material and attracting much attention from universities and enterprises. At present, TPEE has been widely used in automotive parts, wires and cables, foamed shoe materials, breathable films, railway pads and other fields.

[0003] Although TPEE has many advantages such as heat resistance, weather resistance, oil resistance, chemical resistance, aging resistance, fatigue resistance, and wear resistance, it is similar to conventional polyester materials. TPEE has poor combustion resistance, and its limiting oxygen index (LOI) is only about 19%. It is a flammable material. In addition, it produces a lot of smoke and serious molten droplets during the combustion process, which can easily cause secondary combustion, increase the intensity of combustion, and cause more serious losses and harm.

[0004] In the most traditional flame retardant technology, halogen-containing flame retardants are usually used to improve the flame retardant effect of TPEE, such as the common bromine-based and chlorine-based flame retardants, which are added in relatively small amounts and have significant flame retardant effects. However, toxic gases will be produced during the combustion process, which are harmful to the human body and are difficult to remove in the atmosphere, seriously polluting the atmospheric environment and destroying the ozone layer. In addition, dioxanes produced by the decomposition of bromine-containing flame retardants are toxic substances and harmful to the human body. At present, this type of flame retardant has been increasingly banned.

[0005] Among the existing flame retardant modification technologies, phosphorus-based flame retardants are favored by researchers because of their low toxicity and high efficiency flame retardant characteristics. The flame retardant components of the currently common flame retardant TPEE materials are still mainly phosphorus-based flame retardants, usually phosphorus-containing inorganic or organic mixtures such as phosphates, ammonium phosphates, red phosphorus, and phosphate esters. However, although phosphorus-containing flame retardants are effective in flame retardant modification, the amount added in the modification is usually high, which has a great impact on the performance of the material, especially for the elastomer TPEE, which has relatively low strength itself. The strength and toughness of the modified material are significantly reduced, which affects the application field and service life of TPEE to a certain extent; in addition, phosphorus-based flame retardants are mostly small molecule modification additives, which have poor compatibility with the main material and are easy to migrate and precipitate during use, which further reduces the flame retardant modification effect.

[0006] CN106795362A selected inorganic magnesium hydroxide (MgOH) and alumina trihydrate (ATH), organic melamine cyanurate and hypophosphite as flame retardants to prepare low-smoke halogen-free flame-retardant TPEE. Its tensile stress at break and elongation decreased significantly compared with those before modification, and the flame retardant effect was not significant enough. When the flame retardant addition amount was about 60%, the UL-V combustion grade test could reach V0 level, but the tensile strength was only 6MPa, the loss rate exceeded 60%, and the mechanical properties decreased significantly.

[0007] CN102807739A selected aluminum diethylphosphinate (Exolit OP1230) and MPP as flame retardants. When the addition amount of the flame retardant was 30%, the flame retardant effect was significant, reaching the VW-1 level, but the mechanical properties decreased by nearly 60%, resulting in a significant performance loss.

[0008] CN112457635A improves the dripping problem during the combustion process by introducing anti-drip additive polytetrafluoroethylene, thereby effectively reducing the amount of flame retardant aluminum diethylphosphinate added, the elongation of the material remains above 500%, and the vertical combustion level is increased to 0.8mm-V0 level. However, its tensile strength has dropped significantly. The tensile strength of low-hardness 35DTPEE is only 16.3MPa when only 17.8% flame retardant is added, and the performance loss exceeds 20%. When the addition amount is 30%, the loss exceeds 55%. This is because the small molecule flame retardant acts as a plasticizer in TPEE, and the dispersion uniformity is poor, resulting in a greater impact on the tensile properties under higher addition conditions.

[0009] In view of the current modified application of flame retardants in TPEE, with the development of science and technology and social progress, people's requirements for environmental protection are getting higher and higher, and organophosphorus flame retardants will still be the dominant flame retardants in the future. However, organophosphorus flame retardants still show many problems such as poor compatibility with polymer materials, poor thermal stability, and great influence on the mechanical properties of materials.

[0010] Therefore, how to provide a halogen-free flame retardant thermoplastic polyester elastomer with good compatibility between the flame retardant and the thermoplastic polyester elastomer, in which the flame retardant is not easy to precipitate, and has both good flame retardancy and good mechanical properties has become a technical problem that needs to be solved urgently. Summary of the invention

[0011] In view of the shortcomings of the prior art, the object of the present invention is to provide a halogen-free flame-retardant thermoplastic polyester elastomer and a preparation method thereof. The present invention designs the specific composition of the halogen-free flame-retardant thermoplastic polyester elastomer and further solves the problem of poor compatibility and easy precipitation of flame retardants in polyether ester type TPEE by using polymeric phosphorus flame retardants, thereby preparing a halogen-free flame-retardant thermoplastic polyester elastomer with good flame retardancy and good mechanical properties.

[0012] To achieve this object, the present invention adopts the following technical solutions:

[0013] In a first aspect, the present invention provides a halogen-free flame retardant thermoplastic polyester elastomer, wherein the halogen-free flame retardant thermoplastic polyester elastomer comprises the following components in parts by weight:

[0014]

[0015] The present invention designs the specific composition of the halogen-free flame-retardant thermoplastic polyester elastomer and further solves the problems of poor compatibility and easy precipitation of the flame retardant in polyether ester type TPEE by using a polymeric phosphorus-based flame retardant, thereby preparing a halogen-free flame-retardant thermoplastic polyester elastomer with both good flame retardancy and good mechanical properties.

[0016] Polymeric phosphorus flame retardant is a high molecular weight phosphorus-containing polymer, which forms an interpenetrating network structure with polyether ester TPEE resin after mixing, which improves the compatibility of flame retardant and resin, thereby avoiding the precipitation of flame retardant and a significant decrease in the performance of modified elastomer, so that it still has excellent mechanical properties.

[0017] Compared with the currently common flame retardants such as phosphates, ammonium phosphates, red phosphorus, and phosphate esters, polymeric phosphorus flame retardants retain the high-efficiency flame retardant characteristics of phosphorus flame retardants. At the same time, they can form an interpenetrating network structure with macromolecular resins and have better compatibility. On the one hand, they are not easy to precipitate from the matrix resin, making the flame retardant period more durable; on the other hand, they have less plasticizing effect on the matrix resin and are easy to retain the excellent mechanical properties of the matrix resin.

[0018] Although phosphorus-based flame retardants can effectively improve the combustion resistance of TPEE, due to the large amount of heat released and the violent reaction during the combustion process, the carbon layer formed by the combustion may still melt and drip, causing the risk of secondary combustion. Therefore, the present invention uses an anti-melting dripping agent to increase the melt strength, reduce the melt fluidity during the combustion process, improve the stability and density of the carbon layer, and prevent the dripping of melts and combustion products during the combustion process.

[0019] In the present invention, a halogen-free flame-retardant thermoplastic polyester elastomer with excellent comprehensive performance is prepared by controlling the amount of the polymeric phosphorus flame retardant within a specific range. If the amount of the polymeric phosphorus flame retardant is too small, the flame retardancy of the prepared halogen-free flame-retardant thermoplastic polyester elastomer is poor; if the amount of the polymeric phosphorus flame retardant is too large, the strength, elasticity, toughness and other comprehensive properties of the modified polyester elastomer will inevitably be reduced. At the same time, if the amount of the polymeric phosphorus flame retardant is too large, the cost is too high and the promotion and application are limited.

[0020] In the present invention, the weight proportion of the polymeric phosphorus-based flame retardant in the halogen-free flame-retardant thermoplastic polyester elastomer can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts or 30 parts, etc.

[0021] The weight proportion of the anti-drip agent in the halogen-free flame retardant thermoplastic polyester elastomer can be 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, 0.6 parts, 0.65 parts, 0.7 parts, 0.75 parts or 0.8 parts, etc.

[0022] The weight proportion of the heat stabilizing agent in the halogen-free flame retardant thermoplastic polyester elastomer may be 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts or 0.6 parts, etc.

[0023] The weight proportion of the polymeric phosphorus-based flame retardant in the halogen-free flame-retardant thermoplastic polyester elastomer may be 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts or 0.5 parts, etc.

[0024] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0025] As a preferred technical solution of the present invention, the mass percentage of phosphorus element in the polymeric phosphorus-based flame retardant is 8-20%, for example, it can be 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc.

[0026] Preferably, the polymeric phosphorus-based flame retardant has a melt index of 6-20 g / 10 min at 240° C. and 1.2 kg, for example, 6 g / 10 min, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 14 g / 10 min, 16 g / 10 min, 18 g / 10 min or 20 g / 10 min.

[0027] In the present invention, the test method for the melt index of the polymeric phosphorus-based flame retardant at 240° C. and 1.2 kg is completed by using the method of GB / T 3682-2000.

[0028] Preferably, the limiting oxygen index (LOI) of the polymeric phosphorus flame retardant is 50-70%, for example, it can be 50%, 52%, 54%, 56%, 58%, 60%, 62%, 64%, 66%, 68% or 70%.

[0029] In the present invention, the limiting oxygen index (LOI) of the polymeric phosphorus flame retardant is tested according to the method of GB / T2406.2-2009.

[0030] Preferably, the decomposition temperature of the polymeric phosphorus-based flame retardant is ≥ 440°C, for example, it may be 440°C, 442°C, 444°C, 446°C, 448°C, 450°C, 452°C, 454°C, 456°C, 458°C or 460°C.

[0031] In the present invention, the decomposition temperature test method of the polymeric phosphorus-based flame retardant adopts the method of GB / T1634-2004 and uses a thermogravimetric analyzer (TGA) to complete the test.

[0032] The invention prepares a thermoplastic polyester elastomer with excellent flame retardant performance by selecting a polymerizable phosphorus flame retardant with phosphorus content (content of phosphorus element), melt index and decomposition temperature within a specific range and with a relatively high limiting oxygen index.

[0033] Preferably, the polymeric phosphorus-based flame retardant comprises a polyphosphate ester having a branched structure, and the polyphosphate ester having a branched structure has the following structural formula:

[0034]

[0035] Wherein, R represents a terminal group, and R is selected from a methyl diphenoxy phosphine oxide group or a group containing a bisphenol A structure;

[0036] n represents the degree of polymerization of the repeating segment, and n is selected from an integer. Preferably, n is 3-20, for example, 3, 4, 6, 8, 10, 12, 14, 16, 18 or 20.

[0037] In the present invention, the branched polyphosphate having the above structural formula is prepared by polymerization using methyl diphenyl phosphine oxide and bisphenol A as main raw materials, 1,1,1-tri(4-hydroxyphenyl)ethane as a branching agent, and tetraphenylphosphine phenolate as a catalyst.

[0038] Preferably, the polymeric phosphorus-based flame retardant includes polyphosphate ester Nofia-HM1100 and / or polyphosphate ester Nofia-HM9000 produced by FRX Polymers.

[0039] The present invention selects a polymeric phosphorus flame retardant with a specific structure to further optimize the flame retardancy of the thermoplastic polyester elastomer.

[0040] As a preferred technical solution of the present invention, the content of terminal carboxyl groups in the polyether ester type TPEE is ≤30 mmol / kg, for example, it can be 3 mmol / kg, 6 mmol / kg, 9 mmol / kg, 12 mmol / kg, 15 mmol / kg, 18 mmol / kg, 21 mmol / kg, 24 mmol / kg, 27 mmol / kg or 30 mmol / kg, etc.

[0041] In the present invention, the test method for the terminal carboxyl group in the polyether ester type TPEE is tested by the determination method of the terminal carboxyl group in GB / T 14190-2017.

[0042] The present invention controls the content of terminal carboxyl groups in the polyether ester type TPEE within a specific range, so that the prepared flame retardant thermoplastic polyester elastomer has bright white color without color stains, and has stable heat resistance and hydrolysis resistance. If the content of terminal carboxyl groups in the polyether ester type TPEE is too large, the comprehensive performance of the flame retardant thermoplastic polyester elastomer will be reduced, and the risk of degradation will be aggravated in subsequent processing and modification, affecting the appearance and performance of the modified sample.

[0043] Preferably, the melting point of the polyetherester TPEE is 180-220°C, for example, it may be 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C or 220°C.

[0044] Preferably, the melt index of the polyetherester TPEE at 230°C and 2.16kg is 6-30g / 10min, for example, it can be 6g / 10min, 8g / 10min, 10g / 10min, 12g / 10min, 14g / 10min, 16g / 10min, 18g / 10min, 20g / 10min, 22g / 10min, 24g / 10min, 26g / 10min, 28g / 10min or 30g / 10min, etc.

[0045] In the present invention, the test method for the melt index of polyetherester TPEE at 230° C. and 2.16 kg is carried out using the method of GB / T3682-2000.

[0046] Preferably, the hardness of the polyetherester TPEE is 30-45D, for example, it may be 30D, 31D, 32D, 33D, 34D, 35D, 36D, 37D, 38D, 39D or 45D.

[0047] In the present invention, the hardness of polyetherester TPEE is tested by the method in GB / T 2411-2008.

[0048] The hardness of the polyether ester TPEE is controlled within a specific range in the present invention, so that the prepared flame retardant thermoplastic polyester elastomer meets the current practical applications of flame retardant TPEE in automotive parts, new energy charging piles, wires and cables, and soft pipes. By comparing the performance differences between the flame retardant polyether ester TPEE prepared by the present invention and the flame retardant TPEE currently on the market, the excellent performance of the flame retardant polyether ester TPEE prepared by the present invention can be further verified.

[0049] As a preferred technical solution of the present invention, the polyetherester type TPEE is prepared by the following method, which comprises the following steps:

[0050] (1) mixing an aromatic dibasic acid, a small molecule diol, a polyether polyol and a part of a catalyst to carry out an esterification reaction to obtain an esterified product;

[0051] (2) adding the remaining catalyst to the reaction system of step (1) to carry out a preliminary polycondensation reaction;

[0052] (3) subjecting the reaction system obtained in step (2) to a final polycondensation reaction to obtain the polyetherester type TPEE.

[0053] As a preferred technical solution of the present invention, the aromatic dibasic acid is selected from any one of terephthalic acid, isophthalic acid or naphthalene-2,6-dicarboxylic acid or a combination of at least two thereof.

[0054] Preferably, the small molecule diol is selected from any one of ethylene glycol (EG), propylene glycol (HDO), butanediol (BDO) or diethylene glycol (DEG) or a combination of at least two thereof.

[0055] Preferably, the polyether polyol is selected from any one of polyethylene glycol (PEG), polypropylene glycol (PPG) or polytetramethylene glycol (PTMG) or a combination of at least two thereof.

[0056] Preferably, the number average molecular weight of the polyether polyol is 600-6000 g / mol, for example, it can be 600 g / mol, 1000 g / mol, 1500 g / mol, 2000 g / mol, 2500 g / mol, 3000 g / mol, 3500 g / mol, 4000 g / mol, 4500 g / mol, 5000 g / mol, 5500 g / mol or 6000 g / mol, etc.

[0057] Preferably, the catalyst includes at least one of an antimony-based catalyst, a titanium-based catalyst, a zinc-based catalyst or a germanium-based catalyst, illustratively including but not limited to antimony trioxide, antimony glycol, tetrabutyl titanate, tetraisopropyl titanate, zinc acetate, etc.

[0058] As a preferred technical solution of the present invention, the molar ratio of the aromatic dibasic acid to the small molecule diol is 1:(1.2-2.5), for example, it can be 1:1.2, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4 or 1:2.5, etc.

[0059] Preferably, taking the mass percentage of the aromatic dibasic acid, small molecule diol and polyether polyol as 100%, the mass percentage of the polyether polyol is 40-70%, for example, it can be 40%, 43%, 46%, 49%, 52%, 55%, 58%, 61%, 64%, 67% or 70%, etc.

[0060] Preferably, based on the mass percentage of the aromatic dibasic acid, small molecule diol and polyether polyol as 100%, the mass percentage of the catalyst is 0.05-0.5%, for example, it can be 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45% or 0.5%, etc.

[0061] Preferably, based on 100% of the amount of the catalyst, the mass percentage of the catalyst added in step (1) is 30-80%, for example, it can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80%, etc.

[0062] As a preferred technical solution of the present invention, the raw materials for preparing the polyetherester type TPEE also include auxiliary agents.

[0063] Preferably, the auxiliary agent includes an antioxidant.

[0064] Preferably, the antioxidant comprises any one of a hindered phenol antioxidant, an amine antioxidant, a phosphite antioxidant or a thioester antioxidant, or a combination of at least two thereof, illustratively including but not limited to: antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 1098 or antioxidant 412S.

[0065] In the present invention, an antioxidant may be added in step (1).

[0066] It should be noted that the present invention does not have any special restrictions on the specific dosage of the antioxidant, and the dosage range commonly used in the art is applicable.

[0067] Preferably, based on the mass percentage of the aromatic dibasic acid, small molecule diol and polyether polyol as 100%, the mass percentage of the auxiliary agent is 0.2-1.0%, for example, it can be 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1%, etc.

[0068] As a preferred technical solution of the present invention, the temperature of the esterification reaction in step (1) is 200-230°C (for example, it can be 200°C, 203°C, 206°C, 209°C, 212°C, 215°C, 218°C, 221°C, 224°C, 227°C or 230°C, etc.), and the time is 2-4h (for example, it can be 2h, 2.5h, 3h, 3.5h or 4h, etc.).

[0069] Preferably, the esterification reaction in step (1) is carried out in a protective gas atmosphere, and the protective gas includes nitrogen.

[0070] Preferably, the esterification reaction in step (1) is carried out under normal pressure.

[0071] Preferably, the acid value of the esterified product is ≤10 mgKOH / g, for example, it may be 1 mgKOH / g, 2 mgKOH / g, 3 mgKOH / g, 4 mgKOH / g, 5 mgKOH / g, 6 mgKOH / g, 7 mgKOH / g, 8 mgKOH / g, 9 mgKOH / g or 10 mgKOH / g, etc.

[0072] Preferably, the temperature of the pre-polycondensation reaction in step (2) is 230-240°C (for example, it can be 230°C, 231°C, 232°C, 233°C, 234°C, 235°C, 236°C, 237°C, 238°C, 239°C or 240°C, etc.), the time is 0.5-1h (for example, it can be 30min, 40min, 50min or 60min, etc.), and the vacuum degree is ≤1000Pa (for example, it can be 500Pa, 550Pa, 600Pa, 650Pa, 700Pa, 750Pa, 800Pa, 850Pa, 900Pa, 950Pa or 1000Pa, etc.).

[0073] Preferably, the temperature of the final polycondensation reaction in step (3) is 240-260°C (for example, it may be 240°C, 242°C, 244°C, 246°C, 248°C, 250°C, 252°C, 254°C, 256°C, 258°C or 260°C, etc.), the time is 1-3h (for example, it may be 1h, 1.5h, 2h, 2.5h or 3h, etc.), and the vacuum degree is ≤200Pa (for example, it may be 100Pa, 110Pa, 120Pa, 130Pa, 140Pa, 150Pa, 160Pa, 170Pa, 180Pa, 190Pa or 200Pa, etc.).

[0074] As a preferred technical solution of the present invention, the polyetherester type TPEE is prepared by the following method, which specifically comprises the following steps:

[0075] (1) mixing an aromatic dibasic acid, a small molecule diol, a polyether polyol, a part of a catalyst, and an optional auxiliary agent, and performing an esterification reaction at 200-230° C. for 2-4 hours under a protective gas atmosphere and normal pressure to obtain an esterified product with an acid value of ≤10 mgKOH / g;

[0076] The molar ratio of the aromatic dibasic acid to the small molecule diol is 1:(1.5-2.5);

[0077] Taking the mass percentage of the aromatic dibasic acid, the small molecule diol and the polyether polyol as 100%, the mass percentage of the polyether polyol is 40-70%;

[0078] Taking the mass percentage of the aromatic dibasic acid as 100%, the mass percentage of the catalyst is 0.05-0.5%;

[0079] Taking the amount of the catalyst as 100%, the mass percentage of the catalyst added in step (1) is 45-55%;

[0080] (2) adding the remaining catalyst to the reaction system of step (1), evacuating to a vacuum degree of ≤1000 Pa, and heating to 230-240° C. to carry out a pre-polycondensation reaction for 0.5-1 h;

[0081] (3) Continue to evacuate until the vacuum degree is ≤200 Pa, raise the temperature to 240-260° C., and perform a final polycondensation reaction on the reaction system obtained in step (2) for 1-3 hours to obtain the polyetherester type TPEE.

[0082] The present invention prepares polyether ester type TPEE with excellent performance by designing the preparation raw materials and process conditions of polyether ester type TPEE. The halogen-free flame retardant thermoplastic elastomer prepared from the polyether ester type TPEE has both good flame retardancy and good mechanical properties.

[0083] As a preferred technical solution of the present invention, the anti-dripping agent includes montmorillonite and / or polytetrafluoroethylene.

[0084] Preferably, the heat stabilizing aid comprises a combination of a hindered phenol antioxidant and a phosphite antioxidant.

[0085] Preferably, the hindered phenol antioxidant includes antioxidant 1010, and the phosphite antioxidant includes antioxidant 168.

[0086] Preferably, the ultraviolet absorber includes ultraviolet absorber UV-326 and / or ultraviolet absorber UV-531.

[0087] In a second aspect, the present invention provides a method for preparing the halogen-free flame-retardant thermoplastic polyester elastomer as described in the first aspect, the preparation method comprising the following steps:

[0088] The components of the halogen-free flame-retardant thermoplastic polyester elastomer are mixed, melted, extruded and granulated to obtain the halogen-free flame-retardant thermoplastic polyester elastomer.

[0089] Preferably, the mixing method comprises mixing using a high-speed mixer.

[0090] Preferably, the melt extrusion method comprises using a twin-screw extruder for melt extrusion granulation, the barrel temperature of the twin-screw extruder is 190-230°C (for example, it can be 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C or 230°C, etc.), the screw speed is 170-250rpm (for example, it can be 170rpm, 180rpm, 190rpm, 200rpm, 210rpm, 220rpm, 230rpm, 240rpm, etc.), and the melt extrusion method comprises using a twin-screw extruder for melt extrusion granulation, the barrel temperature of the twin-screw extruder is 190-230°C (for example, it can be 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C or 230°C, etc.), and the screw speed is 170-250rpm (for example, it can be 170rpm, 180rpm, 190rpm, 200rpm, 210rpm, 220rpm, 230rpm, 240rpm, etc.). rpm or 250rpm, etc.), the feeding speed is 6-12rpm (for example, it can be 6rpm, 7rpm, 8rpm, 9rpm, 10rpm, 11rpm or 12rpm, etc.), and the vacuum degree is -0.06MPa to -0.1MPa (for example, it can be -0.06MPa, -0.065MPa, -0.07MPa, -0.075MPa, -0.08MPa, -0.085MPa, -0.09MPa, -0.095MPa or -0.1MPa, etc.).

[0091] Compared with the prior art, the present invention has the following beneficial effects:

[0092] (1) The present invention designs the specific composition of the halogen-free flame-retardant thermoplastic polyester elastomer and further solves the problem of poor compatibility and easy precipitation of flame retardants in polyether ester type TPEE by using polymeric phosphorus-based flame retardants, thereby preparing a halogen-free flame-retardant thermoplastic polyester elastomer with both good flame retardancy and good mechanical properties.

[0093] (2) The present invention further optimizes the comprehensive performance of the halogen-free flame-retardant thermoplastic polyester elastomer by combining a polyetherester-type TPEE with specific performance requirements and a polymeric phosphorus-based flame retardant with a specific structure.

[0094] (3) The flame retardant thermoplastic polyester elastomer prepared by the present invention does not contain halogen and meets the flame retardant requirements for elastomer materials in the fields of electronics and automobiles at home and abroad. DETAILED DESCRIPTION

[0095] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0096] The sources of some components used in the following preparation examples and comparative preparation examples are shown in Table 1 below:

[0097] Table 1

[0098]

[0099]

[0100] Preparation Examples 1-6 and Comparative Preparation Examples 1-3

[0101] Preparation Examples 1-6 and Comparative Preparation Examples 1-3 respectively provide a polyether ester type TPEE and a preparation method thereof. The preparation method of the polyether ester type TPEE is as follows:

[0102] (1) mixing an aromatic dibasic acid, a small molecule diol, a polyether polyol, a part of a catalyst, and an optional antioxidant, and performing an esterification reaction under a nitrogen atmosphere and normal pressure to obtain an esterified product;

[0103] (2) adding the remaining catalyst to the reaction system of step (1), evacuating the system, and performing a preliminary polycondensation reaction;

[0104] (3) continuing to evacuate the reaction system obtained in step (2) to perform a final polycondensation reaction to obtain the polyetherester type TPEE;

[0105] The specific selection and dosage of the aromatic dibasic acid, small molecule diol, polyether polyol, catalyst, and antioxidant in Preparation Examples 1-6 and Comparative Preparation Examples 1-3, as well as the reaction conditions in steps (1) to (3) are shown in Tables 2 and 3 below.

[0106] The acid value of the ester obtained in step (1) is tested by the following method: 0.2 g of the ester is weighed and placed in a conical flask, 30 ml of a toluene-ethanol mixture is added, and the mixture is placed in a 70° C. heating environment to dissolve, 10 drops of phenolphthalein indicator solution are titrated, and then titrated with a KOH standard solution until a slightly reddish color does not fade for 30 seconds, which is the titration endpoint, and the acid value is calculated based on the amount of KOH consumed.

[0107] Comparative Preparation Example 4

[0108] This comparative preparation example provides a polyether ester type TPEE, and the polyether ester type TPEE is purchased from Jiangyin Hechuang, with a brand name of H40DMG.

[0109] The performance of the polyether ester type TPEE provided in the above preparation examples and comparative preparation examples was tested, and the specific test method is as follows:

[0110] Terminal carboxyl content: Tested according to the determination method of terminal carboxyl in 5.4 of GB / T 14190-2017;

[0111] Melting point: The melting point of the sample was tested according to the DSC method in GB / T 19466-2009;

[0112] Melt index: Tested according to the method in GB / T 3682-2000;

[0113] Tensile strength and elongation: tensile specimens were prepared according to the methods in GB / T 1040.3-2006 and 1040.1-2018, and the performance tests were completed using an Instron universal testing machine in the laboratory.

[0114] The above performance test results are shown in Table 2 and Table 3 below:

[0115] Table 2

[0116]

[0117]

[0118] Table 3

[0119]

[0120]

[0121] The sources of some components in the following examples and comparative examples are shown in Table 4 below:

[0122] Table 4

[0123] Components illustrate Polymeric phosphorus flame retardant 1 Nofia-HM1100, purchased from FRX Polymers Polymeric phosphorus flame retardant 2 Nofia-HM9000, purchased from FRX Polymers Polymeric phosphorus flame retardant A Exolit AP 422, purchased from Clariant Diethylphenylaluminum hypophosphite LFR-8001, purchased from Liside New Materials Melamine polyurethane JLS-MC25, purchased from JLS Flame Retardant Chemicals Montmorillonite GEKO P, purchased from Clariant Polytetrafluoroethylene (PTFE) FR-2600, purchased from Zhenming Chemical Heat Stabilizer Antioxidant B215, purchased from Lionlon UV absorber UV-326, purchased from Lianlong

[0124] Example 1-Example 14, Comparative Example 1-Comparative Example 4

[0125] Example 1 to Example 14 and Comparative Example 1 to Comparative Example 4 respectively provide a halogen-free flame retardant thermoplastic polyester elastomer, and the specific composition of the halogen-free flame retardant thermoplastic polyester elastomer is shown in Table 5 to Table 7 below (the amount of each component in Table 5 to Table 7 is in parts by weight);

[0126] The preparation method of the halogen-free flame-retardant thermoplastic polyester elastomer is as follows:

[0127] After mixing the components of the halogen-free flame-retardant thermoplastic polyester elastomer using a high-speed mixer, the mixture is placed in a twin-screw extruder for melt extrusion granulation, the barrel temperature is 190-230° C., the screw speed is 200 rpm, the feed speed is 10 rpm, and the vacuum degree is -0.03 MPa to obtain the halogen-free flame-retardant thermoplastic polyester elastomer.

[0128] Comparative Example 5

[0129] This comparative example provides a halogen-free flame-retardant thermoplastic polyester elastomer purchased from Sichuan Chenguangke, with a new brand name of FK40.

[0130] Comparative Example 6

[0131] This comparative example provides a halogen-free flame-retardant thermoplastic polyester elastomer purchased from Jiangyin Hechuang with a brand name of C40DHF.

[0132] Table 5

[0133]

[0134] Table 6

[0135]

[0136] Table 7

[0137]

[0138] The properties of the halogen-free flame-retardant thermoplastic polyester elastomers provided in the above embodiments and comparative examples were tested, and the specific testing method is as follows:

[0139] UL-94 (1.6mm): Tested in accordance with the national standard GB / T 2408-2008;

[0140] UL-94 (3.2mm): Tested in accordance with the national standard GB / T 2408-2008;

[0141] Limiting oxygen index (LOI) / %: tested in accordance with the national standard GB / T 2406.2-2009;

[0142] Tensile strength / MPa: tested in accordance with standard GB / T 1040-2006;

[0143] Elongation / %: Tested in accordance with standard GB / T 1040-2006.

[0144] The above performance test results are shown in Table 8:

[0145] Table 8

[0146]

[0147]

[0148] From the above content, it can be seen that the present invention solves the problems of poor compatibility, easy precipitation and significantly reduced mechanical properties of flame retardants in polyether ester TPEE by designing the specific composition of the halogen-free flame retardant thermoplastic polyester elastomer and further using a polymeric phosphorus-based flame retardant, thereby preparing a halogen-free flame retardant thermoplastic polyester elastomer with good flame retardancy and good mechanical properties, wherein the UL-94 (1.6mm) grade is V0 or V1, the UL-94 (1.6mm) grade is V0 or V1, the limiting oxygen index is 29.0-31.2%, the tensile strength is 10.1-23.7MPa, and the elongation is 515-690%.

[0149] The present invention further optimizes the comprehensive performance of the halogen-free flame-retardant thermoplastic polyester elastomer through the cooperation of a polyether-ester type TPEE with specific performance requirements and a polymeric phosphorus-based flame retardant with a specific structure. The UL-94 (1.6 mm) grade is V0, the UL-94 (3.2 mm) grade is V0, the limiting oxygen index is greater than 30%, the tensile strength loss rate is less than 20% compared with that before flame-retardant modification, specifically 14.9-20.8 MPa, the elongation loss rate is less than 30% compared with that before flame-retardant modification, and is 605-660%. The mechanical properties are better maintained, which is significantly better than the existing halogen-free flame-retardant polyester elastomers currently on the market.

[0150] According to Example 1, Examples 13-14 and Comparative Examples 1-2 of the present application, the present invention prepares a halogen-free flame retardant thermoplastic polyester elastomer with excellent comprehensive performance by designing the dosage of the polymerizable phosphorus-based flame retardant within a specific range.

[0151] It can be seen from Comparative Example 3 that the comprehensive mechanical properties of the halogen-free flame-retardant thermoplastic polyester elastomer prepared by using the most common small molecule flame retardant to replace the polymeric phosphorus flame retardant in the present invention are poor.

[0152] It can be seen from Comparative Example 4 that if the anti-dripping agent is not used, the flame retardant grade of the prepared halogen-free flame retardant thermoplastic polyester elastomer cannot reach V0 grade.

[0153] It can be seen from Comparative Examples 5-6 that the present invention designs the specific composition of the halogen-free flame retardant thermoplastic polyester elastomer. Compared with the halogen-free flame retardant thermoplastic polyester elastomer currently on the market, the prepared halogen-free flame retardant thermoplastic polyester elastomer has better flame retardancy and better mechanical properties.

[0154] In summary, the present invention solves the problems of poor compatibility, easy precipitation and severe damage to mechanical properties of current flame retardants in polyetherester TPEE by designing the specific composition of the halogen-free flame retardant thermoplastic polyester elastomer and further using a polymeric phosphorus-based flame retardant, thereby preparing a halogen-free flame retardant thermoplastic polyester elastomer with both good flame retardancy and good mechanical properties.

[0155] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A halogen-free flame-retardant thermoplastic polyester elastomer, characterized in that: The halogen-free flame-retardant thermoplastic polyester elastomer comprises the following components in parts by weight:

2. The halogen-free flame-retardant thermoplastic polyester elastomer according to claim 1, characterized in that: The mass percentage of phosphorus in the polymeric phosphorus flame retardant is 8 to 20%; Preferably, the polymeric phosphorus flame retardant has a melt index of 6 to 20 g / 10 min at 240° C. and 1.2 kg; Preferably, the limiting oxygen index of the polymeric phosphorus flame retardant is 50-70%; Preferably, the decomposition temperature of the polymeric phosphorus flame retardant is ≥ 440°C; Preferably, the polymeric phosphorus-based flame retardant comprises a polyphosphate ester having a branched structure, and the polyphosphate ester having a branched structure has the following structural formula: Wherein, R is selected from a methyl diphenoxy phosphine oxide group or a group containing a bisphenol A structure; n represents the degree of polymerization of the repeating segment, and n is selected from integers; Preferably, n is 3-20; Preferably, the polymeric phosphorus-based flame retardant includes polyphosphate ester Nofia-HM1100 and / or polyphosphate ester Nofia-HM9000 produced by FRX Polymers.

3. The halogen-free flame-retardant thermoplastic polyester elastomer according to claim 1 or 2, characterized in that: The content of terminal carboxyl groups in the polyether ester type TPEE is ≤30mmol / kg; Preferably, the melting point of the polyetherester TPEE is 180-220°C; Preferably, the polyetherester TPEE has a melt index of 6-30 g / 10 min at 230° C. and 2.16 kg; Preferably, the hardness of the polyetherester TPEE is 30-45D.

4. The halogen-free flame-retardant thermoplastic polyester elastomer according to any one of claims 1 to 3, characterized in that: The polyetherester type TPEE is prepared by the following method, which comprises the following steps: (1) mixing an aromatic dibasic acid, a small molecule diol, a polyether polyol and a part of a catalyst to carry out an esterification reaction to obtain an esterified product; (2) adding the remaining catalyst to the reaction system of step (1) to carry out a preliminary polycondensation reaction; (3) subjecting the reaction system obtained in step (2) to a final polycondensation reaction to obtain the polyetherester type TPEE.

5. The halogen-free flame-retardant thermoplastic polyester elastomer according to claim 4, characterized in that: The aromatic dibasic acid is selected from any one of terephthalic acid, isophthalic acid or naphthalene-2,6-dicarboxylic acid or a combination of at least two thereof; Preferably, the small molecule diol is selected from any one or a combination of at least two of ethylene glycol, propylene glycol, butanediol or diethylene glycol; Preferably, the polyether polyol is selected from any one or a combination of at least two of polyethylene glycol, polypropylene glycol or polybutylene glycol; Preferably, the number average molecular weight of the polyether polyol is 600-6000 g / mol; Preferably, the catalyst includes at least one of an antimony-based catalyst, a titanium-based catalyst, a zinc-based catalyst or a germanium-based catalyst.

6. The halogen-free flame-retardant thermoplastic polyester elastomer according to claim 4 or 5, characterized in that: The molar ratio of the aromatic dibasic acid to the small molecule diol is 1:(1.2-2.5); Preferably, based on the mass percentage of the aromatic dibasic acid, the small molecule diol and the polyether polyol as 100%, the mass percentage of the polyether polyol is 40-70%; Preferably, the mass percentage of the catalyst is 0.05-0.5%, based on the mass percentage of the aromatic dibasic acid, the small molecule diol and the polyether polyol as 100%; Preferably, based on 100% of the amount of the catalyst, the mass percentage of the catalyst added in step (1) is 30-80%.

7. The halogen-free flame-retardant thermoplastic polyester elastomer according to any one of claims 4 to 6, characterized in that: The raw materials for preparing the polyether ester type TPEE also include auxiliary agents; Preferably, the auxiliary agent includes an antioxidant; Preferably, the antioxidant comprises any one of a hindered phenol antioxidant, an amine antioxidant, a phosphite antioxidant or a thioester antioxidant, or a combination of at least two thereof; Preferably, based on the mass percentage of the aromatic dibasic acid, the small molecule diol and the polyether polyol being 100%, the mass percentage of the auxiliary agent is 0.2-1%.

8. The halogen-free flame-retardant thermoplastic polyester elastomer according to any one of claims 4 to 7, characterized in that: The temperature of the esterification reaction in step (1) is 200-230° C. and the time is 2-4 hours; Preferably, the esterification reaction in step (1) is carried out in a protective gas atmosphere; Preferably, the acid value of the esterified product is ≤10 mgKOH / g; Preferably, the temperature of the pre-polycondensation reaction in step (2) is 230-240° C., the time is 0.5-1 h, and the vacuum degree is ≤1000 Pa; Preferably, the temperature of the final polycondensation reaction in step (3) is 240-260° C., the time is 1-3 h, and the vacuum degree is ≤200 Pa.

9. The halogen-free flame-retardant thermoplastic polyester elastomer according to any one of claims 1 to 8, characterized in that: The anti-drip agent includes montmorillonite and / or polytetrafluoroethylene; Preferably, the heat stabilizing agent comprises a combination of a hindered phenol antioxidant and a phosphite antioxidant; Preferably, the hindered phenol antioxidant includes antioxidant 1010, and the phosphite antioxidant includes antioxidant 168; Preferably, the ultraviolet absorber includes ultraviolet absorber UV-326 and / or ultraviolet absorber UV-531.

10. A method for preparing a halogen-free flame-retardant thermoplastic polyester elastomer according to any one of claims 1 to 9, characterized in that: The preparation method comprises the following steps: The components of the halogen-free flame-retardant thermoplastic polyester elastomer are mixed, melted, extruded and granulated to obtain the halogen-free flame-retardant thermoplastic polyester elastomer.

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