PPA-POK alloy composition as well as preparation method and application thereof

Abstract

The invention discloses a PPA-POK alloy composition as well as a preparation method and application thereof. The composition is prepared from the following components in parts by weight: 30 to 60 parts of PPA resin, 10 to 20 parts of POK resin, 8 to 20 parts of alkyl phosphinate flame retardant, 1 to 5 parts of compatilizer and 1 to 5 parts of synergist. The preparation method of the composition comprises the following steps: uniformly mixing all the components according to the ratio, and carrying out melt blending, extrusion and granulation. The PPA-POK alloy composition has high thermal deformation temperature and high glowing filament ignition temperature, and is suitable for preparing electrical parts with strict requirements on heat resistance and flame retardance, such as key parts such as relays, circuit breakers and high-voltage connectors.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, and specifically relates to a PPA-POK alloy composition, its preparation method, and its application. Background Technology

[0002] GWIT (Glow Wire Ignition Temperature) refers to the lowest temperature at which a material sample can be ignited by a glow wire under specified test conditions. It is mainly used to evaluate the material's ability to resist ignition by internal hot spots in electrical equipment and is one of the core indicators for the safety design of electrical equipment.

[0003] Unattended equipment typically operates for extended periods without monitoring, thus requiring extremely high safety standards for its internal materials. Electronic components and wiring within unattended equipment may generate high temperatures during long-term operation due to various reasons, such as poor contact, overload, or short circuits. If the GWIT (glow-to-ignition) of materials used in the equipment's casing and insulation is low, these high temperatures can easily ignite, leading to equipment malfunctions or even fires. Ensuring high GWIT in equipment components improves reliability in high-temperature environments and reduces equipment damage and safety accidents caused by material combustion. With the increasing prevalence of unattended electrical equipment in industry and energy sectors, the GWIT performance of plastic materials is receiving more attention. Materials and components in unattended equipment need sufficient heat resistance and non-flammability; GWIT is a crucial indicator of the safety of unattended equipment. High-GWIT materials effectively reduce fire risks, ensuring reliable equipment operation and the safety of personnel and property.

[0004] Semi-aromatic polyamides (PPA) possess excellent mechanical properties, high melting point and high heat distortion temperature (HDT), excellent temperature resistance, excellent electrical insulation properties, and are characterized by their halogen-free system, low toxicity, low smoke, and environmental friendliness, making them widely used in the connector field. In electrical equipment, the GWIT (growth efficiency index) performance of plastic materials is crucial. For example, in low-voltage electrical applications, plastic materials within 3mm of electrical connections require a GWIT of ≥750℃, while components such as relay housings, bases, and coil frames typically require a GWIT of ≥775℃. Because red phosphorus has highly efficient flame-retardant properties in both the gas and condensed phases, red phosphorus-flame-retardant polyamides can more easily achieve high GWIT. Compared to red phosphorus-flame-retardant polyamides, dialkyl phosphines often have relatively lower GWIT and are more difficult to develop. However, given the wide application of dialkyl phosphines, developing dialkyl phosphines with high GWIT (≥775℃) is essential.

[0005] In addition, electrical equipment places increasingly higher demands on the heat resistance of plastic materials. This is because, on the one hand, the equipment generates heat when powered on, requiring long-term operational stability; and on the other hand, it is necessary to prevent the spread of flames due to softening at high temperatures during combustion. Currently, plastic parts in direct contact with high-temperature heat sources require a heat distortion temperature of 210-280℃. With the development of the industry, some high-temperature modified materials need to achieve a heat distortion temperature of over 250℃.

[0006] Therefore, it is of great significance to provide a PPA-POK alloy composition that has both high heat distortion temperature and high GWIT performance. Summary of the Invention

[0007] The primary objective of this invention is to solve the aforementioned technical problems and provide a PPA-POK alloy composition with high heat distortion temperature and high GWIT.

[0008] A second objective of the present invention is to provide a method for preparing the above-mentioned PPA-POK alloy composition.

[0009] A third objective of the present invention is to provide applications of the above-described PPA-POK alloy composition.

[0010] A fourth objective of the present invention is to provide an electrical component comprising the above-described PPA-POK alloy composition.

[0011] This invention is achieved through the following technical solution:

[0012] A PPA-POK alloy composition, comprising the following components by weight:

[0013] 30-60 parts of PPA resin;

[0014] 10-20 parts of POK resin;

[0015] 8-20 parts of alkyl phosphinate flame retardant;

[0016] 1-5 parts compatibilizer;

[0017] Synergistic agent 1-5 parts.

[0018] The PPA resin mentioned in this invention refers to semi-aromatic polyamide.

[0019] Preferably, it refers to a polymer formed by the polycondensation reaction of at least one aromatic dicarboxylic acid (or its polyamide derivative, such as diacyl chloride or diester) with at least one aliphatic diamine. Its molecular backbone simultaneously contains rigid aromatic ring structural units provided by the aromatic dicarboxylic acid and flexible aliphatic chain structural units provided by the aliphatic diamine.

[0020] In this invention, the PPA resin has a molar percentage of terephthalic acid or isophthalic acid, or terephthalic acid and isophthalic acid together, accounting for no less than 55% of the total dicarboxylic acid portion in its repeating structural units on its molecular chain.

[0021] In this invention, the weight parts (unit: parts) of the PPA resin can be 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, or any range formed by any two of the above values, preferably 35-55 parts.

[0022] The sum of PPA resin and POK resin described in this invention has a mass content of not less than 40% in the PPA-POK alloy composition.

[0023] Preferably, the relative viscosity of the PPA resin is 1.8-2.4, the test standard is GB / T 12006.1, and the test method is as follows: at a temperature of 25°C, 0.25 g of resin is first dissolved in 25 mL of concentrated sulfuric acid (mass fraction 96%±0.02%), and the viscosity of the resin solution and the viscosity of the concentrated sulfuric acid are tested using an Ubbelohde viscometer. The ratio of the two is the relative viscosity.

[0024] In this invention, the relative viscosity of the PPA resin can be 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, or any range formed by any two of the above values.

[0025] Preferably, the PPA is selected from at least one of PA6T, PA5T / 6T, PA9T, PA10T, PA10T / 66, PA10T / 10I, PA6T / 66, PA6T / 6, PA6T / 6I, PA6I / 6T, PA6T / 6I / 66, and PA6T / 10T.

[0026] More preferably, the PPA resin is selected from at least one of PA6T / 66, PA9T, and PA10T / 10I.

[0027] More preferably, the PPA resin is selected from PA6T / 66.

[0028] In this invention, the POK resin is a polyketone resin, which is a terpolymer of carbon monoxide, ethylene, and propylene, wherein the molar content of carbon monoxide is 40%-60%.

[0029] In this invention, the melt flow index of the POK resin is 5-250 g / (10 min), ASTM D1238, and the test conditions are 240℃ and 2.16 kg. The melt flow index of the POK resin can be: 5, 10, 15, 20, 25, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 6 6, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, or any two of the above values, preferably 40-210 g / (10min), more preferably 45-160 g / (10min).

[0030] In this invention, the weight parts (unit: parts) of the POK resin can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or any range formed by any two of the above values, preferably 13-18 parts, and more specifically 13, 15, 18 parts.

[0031] The POK resin described in this invention has a mass content of not less than 5% in the PPA-POK alloy composition.

[0032] In this invention, the PPA-POK alloy composition further includes 15-50 parts of filler.

[0033] Preferably, the filler is selected from at least one of glass fiber, carbon fiber, and mica.

[0034] More preferably, the filler is selected from glass fiber.

[0035] More preferably, the average fiber diameter of the glass fiber is 0.5-30µm.

[0036] In this invention, the weight parts (unit: parts) of the alkylphosphinate flame retardant can be 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or any range formed by any two of the above values, preferably 10-18 parts, and more preferably 10, 15, 18 parts.

[0037] In this invention, the alkylphosphinate flame retardant is selected from diethylaluminum hypophosphite.

[0038] In this invention, the number of parts by weight (unit: parts) of the compatibilizer can be 1, 2, 3, 4, or 5, or any range formed by any two of the above values, preferably 2-4 parts, and more preferably 2, 3, or 4 parts.

[0039] In this invention, the compatibilizer is selected from maleic anhydride graft copolymers.

[0040] Preferably, the maleic anhydride graft copolymer is selected from maleic anhydride grafted ethylene copolymer.

[0041] In this invention, the weight parts (unit: parts) of the synergist can be 1, 2, 3, 4, 5, or any range formed by any two of the above values, preferably 2-4 parts.

[0042] In this invention, the synergist is selected from at least one of borate, boehmite, and melamine polyphosphate.

[0043] Preferably, the synergist is selected from borates.

[0044] Specifically, the borate is selected from zinc borate.

[0045] Specifically, the melamine polyphosphate is selected from at least one of melamine polyphosphate, melamine aluminum polyphosphate, melamine magnesium polyphosphate, and melamine zinc polyphosphate.

[0046] In this invention, the PPA-POK alloy composition further includes 0.5-2 parts of antioxidant.

[0047] Preferably, the antioxidant is selected from at least one of hindered phenolic antioxidants, amine antioxidants, phosphite antioxidants, and thioester antioxidants.

[0048] Preferably, the PPA-POK alloy composition further includes 1-8 parts of nickel-titanium alloy.

[0049] In this invention, the weight parts (unit: parts) of the nickel-titanium alloy can be 1, 2, 3, 4, 5, 6, 7, 8, or any range formed by any two of the above values, preferably 3-8 parts, and more specifically 3, 4, 5, 6, 7, 8 parts.

[0050] In this invention, nickel-titanium alloy is added to the composition in powder form.

[0051] Adding a specific weight portion of nickel-titanium alloy to the PPA-POK alloy composition can further improve GWIT.

[0052] The present invention provides a method for preparing the above-mentioned PPA-POK alloy composition: all components are mixed evenly according to the ratio, and then melt-blended and extruded into granules.

[0053] Preferably, a twin-screw extruder is used for extrusion.

[0054] Preferably, the screw speed of the twin-screw extruder is 350-450 rpm.

[0055] Preferably, the screw diameter of the twin-screw extruder is 30-40 mm, and the length-to-diameter ratio (L / D) is 40:1-50:1.

[0056] Preferably, the melting temperature during melt blending is 250-300℃.

[0057] Preferably, the extrusion temperature is 200-300℃.

[0058] This invention provides the application of the above-mentioned PPA-POK alloy composition for the preparation of electrical components.

[0059] The present invention also provides an electrical component comprising the above-described PPA-POK alloy composition.

[0060] The electrical components described in this invention include, but are not limited to, the following categories:

[0061] (1) Structural support and insulation components, such as coil frames, bases, and housings of relays / contactors, internal supports and contact supports of circuit breakers, and insulation frames and end caps of motors, etc.

[0062] (2) Arc protection and arc extinguishing components, such as arc extinguishing covers and their grid plate supports in circuit breakers / contactors;

[0063] (3) High-temperature connection and interface components, including high-voltage connector housings, terminal blocks, fuse holders, and charging gun / charging socket housings for new energy vehicles, etc.;

[0064] (4) Battery system and safety isolation components, such as the insulating end plate of the battery module and the cell spacer.

[0065] Compared with the prior art, the present invention has the following advantages:

[0066] This invention achieves a synergistic improvement in high glow wire ignition temperature (GWIT) and heat distortion temperature (HDT): by alloying PPA resin and POK resin and combining them with dialkylphosphinate flame retardants, the material has a high HDT while significantly improving GWIT performance, which can meet the safety requirements of GWIT for key electrical components such as relay housings and circuit breaker brackets.

[0067] The composition of this invention establishes a highly efficient and stable condensed-phase flame-retardant synergistic mechanism: an interaction exists between the carbonyl groups in the POK resin molecular chain and the amide bonds in the PPA resin, forming a well-compatible system with the assistance of a compatibilizer. Under high temperature or combustion conditions, the aromatic ring structure and carbonyl groups in this alloy system synergistically promote cross-linking to form char, rapidly creating a dense, stable, and low-porosity char protective layer. This char layer effectively isolates heat and oxygen from internal transfer and inhibits the escape of internal combustible gases, thereby efficiently suppressing combustion at the condensed-phase level.

[0068] The diethylphosphonate halogen-free flame retardant used can catalyze the char formation of the polymer matrix at high temperatures, strengthening the aforementioned condensed phase barrier layer, and can also decompose to generate free radical scavengers, extinguishing the H· and OH· free radicals required for the combustion chain reaction in the gas phase. This gas-solid phase synergistic flame retardant mechanism interrupts the combustion cycle at its source, forming a highly efficient protection with dual flame retardancy in both the gas and condensed phases, playing a crucial role in preventing the ignition of the glowing wire.

[0069] Furthermore, the nickel-titanium alloy used can efficiently absorb and dissipate heat from its surrounding area within a very short time of contact with the heat source, directly reducing the actual heating temperature of the matrix composition at that point and delaying its reaching the thermal decomposition temperature. This induces stress concentration, microcracks, or micropores at the interface with the polymer matrix. These changes can disrupt the continuous path of heat conduction into the material's interior, increasing thermal resistance. Simultaneously, the nickel-titanium alloy powder may also physically interrupt or interfere with the initial pyrolysis gas channels and flame propagation front that are forming. This rapid physical endothermic reaction and mechanical disturbance buy time for the chemical char formation reaction of the PPA-POK-diethylphosphonate system, potentially resulting in a more irregular and better-covering protective char layer.

[0070] The PPA-POK alloy composition provided by this invention has excellent comprehensive performance, while also taking into account high heat resistance, high glow wire ignition temperature, and meeting the needs of high-end electrical applications. It is particularly suitable for manufacturing key components in unattended electrical equipment with extremely high requirements for long-term thermal stability and fire safety, such as contactor frames, arc extinguishing components, and high-voltage connectors. It provides an ideal material solution for improving the long-term operational reliability and fire safety of high-end electrical equipment. Detailed Implementation

[0071] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0072] The raw materials used in this invention are sourced from:

[0073] PPA resin 1: PA6T / 66, Vicnyl 400, Zhuhai Wantong Special Engineering Plastics Co., Ltd., relative viscosity 2.22;

[0074] PPA resin 2: PA9T, N1000A, Kuraray (Japan), relative viscosity 2.13;

[0075] PPA resin 3: PA10T / 10I, Vicnyl 6100, Zhuhai Wantong Special Engineering Plastics Co., Ltd., relative viscosity 2.12.

[0076] POK resin 1: POKM330F, melt index 60 g / 10min, Hyosung, South Korea;

[0077] POK resin 2: POKM130F, melt flow index 200 g / 10min, Hyosung, South Korea;

[0078] POK resin 3: POKM230A, melt index 150 g / 10min, Hyosung, South Korea;

[0079] POK resin 4: POKM630A, melt flow index 6 g / 10min, Hyosung, South Korea;

[0080] Other resins 1: PA66, PA66 EPR27, Pingdingshan Shenma;

[0081] Other resin 2: PA6, M32800, Guangdong Xinhui Meida.

[0082] Glass fiber 1: ECS10-03-568H, average fiber diameter is 10 micrometers, Jushi Group Co., Ltd.

[0083] Alkylphosphonate flame retardant: aluminum diethylphosphonate, Exolit OP 1480, Clariant.

[0084] Compatibilizer: Fusabond N493, maleic anhydride (MAH) grafted ethylene copolymer, DuPont, USA;

[0085] Synergist 1: Zinc borate XS-ZB-2335, Zhejiang Xusen Flame Retardant Co., Ltd.;

[0086] Synergist 2: Boehmite BG-601, Anhui Yishitong Materials Technology Co., Ltd.;

[0087] Synergist 3: Melamine polyphosphate (MPP), Zhenjiang Xingxing Flame Retardant Co., Ltd.

[0088] Nickel-titanium alloy: TINI-02, Shaanxi Yuruibang New Materials Co., Ltd.

[0089] Antioxidant 1: Hindered amine antioxidant, Tinuvin 123, BASF.

[0090] Test methods:

[0091] (1) Glow wire ignition temperature (GWIT): Tested according to the method in standard IEC 60695-2-13:2021, with a thickness of 1.0 mm. Place the 60*60*1 mm sample on the fixture, adjust the 4 mm diameter nickel-chromium alloy glow wire to the set temperature, start the equipment, press the glow wire vertically on the sample surface, hold for 30 seconds, and then the machine will automatically remove the glow wire. Test 3 samples continuously. During this process, observe in real time whether the sample burns. If it does not burn or the flame lasts for no more than 5 seconds, it is considered qualified. By gradually adjusting the glow wire temperature, finally determine the highest temperature at which the sample just does not ignite, which is the glow wire ignition temperature of the material.

[0092] (2) Heat distortion temperature (HDT): Tested according to the method in standard ISO 75-1 / -2, with a load of 1.8 MPa. The sample size is 80*10*4 mm.

[0093] The embodiments described in this invention are obtained by the following method:

[0094] The components are mixed evenly according to the formula and then extruded and granulated using a twin-screw extruder. The screw speed of the twin-screw extruder is 400 rpm and the length-to-diameter ratio (L / D) is 40:1. The processing conditions for melt extrusion in the extruder are as follows: Zone 1 temperature 260℃, Zone 2 temperature 280℃, Zone 3 temperature 290℃, Zone 4 temperature 300℃, Zone 5 temperature 300℃, Zone 6 temperature 295℃, Zone 7 temperature 290℃, Zone 8 temperature 285℃, Zone 9 temperature 285℃, and die temperature 280℃.

[0095] Table 1. Weight parts and test results of each component in Examples 1-16

[0096] Components / parts by weight Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Example 15 Example 16 PPA resin 1 30 40 50 50 60 50 50 50 50 50 50 50 50 50 PPA resin 2 50 PPA resin 3 50 POK Resin 1 20 15 15 20 10 15 15 15 15 15 15 15 15 POK Resin 2 15 POK Resin 3 15 POK Resin 4 15 Fiberglass 1 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 Alkylphosphonate flame retardants 15 15 15 15 15 15 15 15 15 15 8 20 15 15 15 15 compatibilizer 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Synergist 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Synergist 2 2 Synergist 3 2 Nickel-titanium alloy 4 8 Antioxidant 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Glow wire ignition temperature (GWIT), unit: °C 875 850 850 875 825 850 850 825 850 825 825 875 825 825 875 875 Heat distortion temperature (HDT), unit: °C 267.3 271.5 275.1 272.4 279.2 274.0 274.3 271.6 273.7 277.8 275.4 275.0 275.5 275.7 275.8 276.2

[0097] Table 2. Weight parts of each component and test results for Comparative Examples 1-6

[0098] Components / parts by weight Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 PPA resin 1 50 50 50 50 Other resins 1 50 Other resins 2 50 POK Resin 1 / 15 15 15 15 30 Fiberglass 1 30 30 30 30 30 30 Alkylphosphonate flame retardants 15 / 15 15 15 15 compatibilizer 2 2 2 2 2 2 Synergist 1 2 2 / 2 2 2 Antioxidant 1 1 1 1 1 1 1 Glow wire ignition temperature (GWIT), unit: °C 775 725 800 775 750 875 Heat distortion temperature (HDT), unit: °C 280.3 274.9 273.2 220.8 205 236.5

[0099] As shown in Examples 1-16, the PPA-POK alloy composition provided in this invention has a glow wire ignition temperature ≥825℃ and a heat distortion temperature >260℃. This achieves both an increased glow wire ignition temperature and high heat distortion temperature retention.

[0100] As shown in Comparative Example 1, the glow wire ignition temperature of the composition without added POK resin is only 775℃.

[0101] As shown in Comparative Example 2, the glow wire ignition temperature of the PPA-POK alloy composition without the addition of alkyl phosphonate flame retardant is only 725°C.

[0102] Although the glow wire ignition temperature of the PPA-POK alloy composition without synergist in Comparative Example 3 was somewhat higher than that in Comparative Example 1, it was still lower than that in Example 3 with synergist.

[0103] As can be seen from Comparative Examples 4-5, the synergistic effect of POK resin with other resins is not as good as that of PPA resin.

[0104] As shown in Comparative Example 6, when the amount of POK resin exceeds the upper limit, the ignition temperature of the glow wire increases to the upper limit and the heat distortion temperature deteriorates.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A PPA-POK alloy composition, characterized in that, By weight, it includes the following components 30-60 parts of PPA resin; 10-20 parts of POK resin; 8-20 parts of alkyl phosphinate flame retardant; 1-5 parts compatibilizer; Synergistic agent 1-5 parts.

2. The PPA-POK alloy composition according to claim 1, characterized in that, By weight, it includes the following components: 35-55 parts of PPA resin; 13-18 parts of POK resin; 10-18 parts of alkyl phosphonate flame retardant; 2-4 parts compatibilizer; 2-4 parts of synergist.

3. The PPA-POK alloy composition according to claim 1, characterized in that, The POK resin has a melt index of 5-250 g / (10 min), ASTM D1238, 240℃, 2.16 kg, preferably 40-210 g / (10 min); more preferably 45-160 g / (10 min).

4. The PPA-POK alloy composition according to claim 1, characterized in that, At least one of the following conditions must be met: (a) The alkylphosphinate flame retardant is selected from diethylaluminum hypophosphite; (b) The compatibilizer is selected from maleic anhydride graft copolymers, preferably maleic anhydride graft ethylene copolymers; (c) It also includes 0.5-2 parts of an antioxidant, preferably the antioxidant being selected from at least one of hindered phenolic antioxidants, amine antioxidants, phosphite antioxidants, and thioester antioxidants.

5. The PPA-POK alloy composition according to claim 1, characterized in that, The synergist is selected from at least one of borate, boehmite and melamine polyphosphate, preferably borate.

6. The PPA-POK alloy composition according to claim 1, characterized in that, It also includes at least one of the following components: 15-50 parts of filler; preferably the filler is selected from at least one of glass fiber, carbon fiber, and mica, and preferably glass fiber.

7. The PPA-POK alloy composition according to claim 1, characterized in that, It also includes 1-8 parts of nickel-titanium alloy.

8. A method for preparing a PPA-POK alloy composition according to claims 1-7, characterized in that, All components are mixed evenly according to the formula, and then granulated by melt blending and extrusion.

9. The application of the PPA-POK alloy composition according to claims 1-7 for the manufacture of electrical components.

10. An electrical component, characterized in that, The composition comprises the PPA-POK alloy composition according to any one of claims 1-7.