Polypropylene composition as well as preparation method and application thereof

Abstract

The invention discloses a polypropylene composition as well as a preparation method and application thereof. The polypropylene composition is prepared from the following components in percentage by mass: 72 to 88 percent of flame-retardant polypropylene particles and 12 to 28 percent of long glass fiber master batch, the flame-retardant polypropylene particles comprise the following components in parts by weight: 30-60 parts of polypropylene resin; 15 to 25 parts of piperazine salt; 5 to 15 parts of melamine salt; 0.3 to 2 parts of a flame retardant synergist; 3-6 parts of finished ceramic filler; 1-4 parts of a fluxing agent; 2-6 parts of a flow modifier; 0.5 to 1 part of hyperbranched polyester; the melt flow rate of the polypropylene resin under the conditions of 230 DEG C and 2.16 kg is not less than 50g / 10min. The melt flow rate of the polypropylene resin is adjusted, and the flow modifier and the hyperbranched polyester are added, so that the ablation resistance and the precipitation resistance of the composition can be effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering plastics, and more specifically, relates to a polypropylene composition, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of the new energy industry, the installed capacity of power batteries and energy storage batteries has increased sharply. Traditional metals and thermosetting materials face challenges due to weight and environmental protection issues. Thermoplastic materials are gradually replacing traditional materials due to their lightweight and environmental protection advantages. Local high temperatures in batteries may cause serious accidents, and many international and domestic standards aim to improve the safety and reliability of battery shell materials.

[0003] In this context, it is particularly crucial to develop high-performance, safe and standardized composite materials, which need to have characteristics such as high temperature resistance, impact resistance, and flame retardancy. Polyolefin materials have become a research hotspot due to their low carbon, high flame retardancy, low density, and low harmful gas release. With the booming development of the new energy vehicle and energy storage industries, the demand for energy storage battery packs shows an explosive increasing trend from thermosetting to thermoplastic materials. The core components of battery packs are required to pass the fire resistance test of GB / T 31467.3-2015 and the thermal runaway test of UL2596. Currently, the trend of thin-walled lightweight is obvious, and the existing halogen-free flame retardant reinforced polypropylene materials have problems that the fire resistance cannot meet the requirements and the surface precipitation risk increases sharply. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects or deficiencies in the prior art that the halogen-free flame retardant polypropylene composition cannot meet the requirements of ablation resistance and has a surface precipitation risk, and to provide a polypropylene composition.

[0005] Another purpose of the present invention is to provide a preparation method of the polypropylene composition.

[0006] Another purpose of the present invention is to provide an application of the polypropylene composition.

[0007] In order to achieve the above purposes, the present invention is realized through the following technical solutions:

[0008] A polypropylene composition, the polypropylene composition comprises by mass percentage:

[0009] 72-88% flame retardant polypropylene particles and 12-28% long glass fiber masterbatch;

[0010] The flame retardant polypropylene particles comprise the following components calculated by weight:

[0011] 30-60 parts of polypropylene resin;

[0012] 15-25 parts of piperazine salt;

[0013] 5 to 15 parts of melamine salt;

[0014]

[0015] The melt flow rate of the polypropylene resin under the conditions of 230 °C and 2.16 kg is not less than 50 g / 10 min.

[0016] In the present invention, a polypropylene composition is provided. By using polypropylene resin as the matrix resin and adding a flow modifier and a hyperbranched polyester, a polypropylene composition with good ablation resistance, exudation performance, and good fluidity can be obtained. Specifically, the compounding of piperazine salt and melamine salt can effectively improve the ablation resistance of the material. Adjusting the melt flow rate of the polypropylene resin and adding a flow modifier can effectively reduce the viscosity of the system and avoid the generation of material degradation. The addition of hyperbranched polyester helps the dispersion of each component in the resin system, and can effectively improve the ablation resistance, exudation performance, and mechanical properties, etc. A hyperbranched polyester with amphiphilic segments is introduced, one end binds to the matrix resin, and the other end binds to the strongly polar groups of piperazine salt and melamine salt, improving the interfacial strength between the flame retardant system and the matrix resin, enhancing the compatibility and toughness of the material, and at the same time improving the flame retardant stability of the polyolefin composite material.

[0017] It should be noted that the content of polypropylene resin in the polypropylene composition described in the present invention is preferably not less than 40 wt%.

[0018] Furthermore, the melt flow rate described in the present invention is obtained by testing according to the ISO 1133-1:2022 standard.

[0019] It should be noted that the melt flow rate of the polypropylene resin under the load of 230 °C and 2.16 kg in the present invention is not less than 50 g / 10 min, such as but not limited to not less than 50 g / 10 min, 55 g / 10 min, 60 g / 10 min, 65 g / 10 min, 70 g / 10 min, 75 g / 10 min, 80 g / 10 min, 85 g / 10 min, 90 g / 10 min, 95 g / 10 min, 100 g / 10 min, 105 g / 10 min, 110 g / 10 min, 115 g / 10 min, 120 g / 10 min, 125 g / 10 min, 130 g / min, 135 g / 10 min, 140 g / 10 min, 145 g / 10 min, 150 g / 10 min, 155 g / 10 min or 160 g / 10 min.

[0020] Furthermore, the melt flow rate of the polypropylene resin at 230 °C under a load of 2.16 kg is 60-150 g / 10 min. The polypropylene composition prepared within this range has good impact strength while maintaining fluidity and anti-bleeding performance.

[0021] Specifically, the polypropylene resin includes one or more of homopolypropylene, propylene-ethylene block copolymer, propylene-ethylene random copolymer, and propylene / 1-butene random block copolymer.

[0022] Furthermore, the polypropylene resin is a propylene-ethylene block copolymer.

[0023] Furthermore, the melt flow rate of the flow modifier at 190 °C under a load of 2.16 kg is 30-300 g / 10 min.

[0024] Even further, the melt flow rate of the flow modifier at 190 °C under a load of 2.16 kg is 100-200 g / 10 min. The polypropylene composition prepared within this range has better fluidity and anti-bleeding performance.

[0025] Furthermore, the flow modifier is polybutene-1.

[0026] Furthermore, the hyperbranched polyester is a hydroxyl-terminated hyperbranched polyester.

[0027] Specifically, the hydroxyl-terminated hyperbranched polyester is a hyperbranched polyester with trimellitic anhydride as the core, AB2-type monomers synthesized from trimellitic anhydride and ethylene glycol as the branches, and capped with a vinyl-containing compound.

[0028] Furthermore, the hydroxyl content of the hyperbranched polyester is not less than 40 wt%.

[0029] Even further, the hydroxyl content of the hyperbranched polyester is 45-75 wt%.

[0030] Specifically, the measurement method for the hydroxyl content is the anhydride-sulfuric acid method.

[0031] Furthermore, the number average molecular weight of the hyperbranched polyester is 3500-6500 g / mol.

[0032] Specifically, the measurement method for the number average molecular weight is the gel permeation chromatography-wide distribution standard sample calibration method.

[0033] Furthermore, the hyperbranched polyester can be selected from one or more of HBP-158 and HyPer C100 of Wuhan Hyperbranched.

[0034] The piperazine salt includes one or more of piperazine phosphate, piperazine pyrophosphate or polyphosphoric acid piperazine.

[0035] Preferably, the piperazine salt is piperazine pyrophosphate.

[0036] The melamine salt includes one or more of melamine phosphate, melamine pyrophosphate or melamine polyphosphate.

[0037] Preferably, the melamine salt is melamine polyphosphate.

[0038] Furthermore, the mass ratio of the piperazine salt to the melamine salt is (1.2 - 3):1.

[0039] Furthermore, the mass ratio of the piperazine salt to the melamine salt is (1.8 - 2.5):1, such as but not limited to 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1 or 2.5:1, etc. The polypropylene composition prepared within this range has better precipitation properties.

[0040] The flame retardant synergist includes one or more of zinc oxide, magnesium oxide, aluminum oxide, lanthanum oxide or silicon dioxide.

[0041] Preferably, the D50 particle size of the flame retardant synergist is 0.01 - 15 μm.

[0042] The flux includes one or more of ammonium borate, zinc borate, boron frit, low melting point glass powder, nano - sepiolite or montmorillonite.

[0043] Preferably, the flux is nano - sepiolite.

[0044] Preferably, the D50 particle size of the flux is 6 - 10 μm.

[0045] The ceramizing filler includes one or more of kaolin, talc powder, wollastonite, white carbon black, sericite, muscovite or quartz powder.

[0046] Preferably, the ceramizing filler is spherical, rod - shaped or flake - shaped ceramizing filler.

[0047] Preferably, the D50 particle size of the ceramizing filler is 6 - 40 μm.

[0048] In some specific embodiments, the aspect ratio of the ceramizing filler is (15 - 20):1 and D50 ≥ 10 μm.

[0049] Furthermore, the long glass fiber content in the long glass fiber masterbatch is 30 - 60 wt%.

[0050] Specifically, the particle length of the long glass fiber masterbatch is 6 - 10 mm.

[0051] The matrix resin in the long glass fiber masterbatch is polypropylene, including copolymerized polypropylene and / or homopolymerized polypropylene.

[0052] Further, the flame-retardant polypropylene particles include the following components calculated by weight:

[0053]

[0054] Further, the flame-retardant polypropylene particles further include 0.1 to 5 parts of an auxiliary agent.

[0055] Further, the auxiliary agent includes one or more of an antioxidant, a lubricant, a weathering agent, or a color powder.

[0056] In the present invention, the antioxidant can be selected from common antioxidants, such as but not limited to one or more of hindered phenol antioxidants, phosphite antioxidants, or thioester antioxidants.

[0057] The hindered phenol antioxidants include one or more of pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 1010), tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (antioxidant 3114), ethylene bis(oxyethylene) bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] (Irganox 245), 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)acrylic acid]-1,1-dimethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane (ADK AO-80), N,N'-hexamethylenebis(3,5-di-tert-butyl-4-hydroxybenzamide) (Irganox 1098), 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (Irganox 259), or n-octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox 1076).

[0058] The phosphite antioxidants are one or more of tris(2,4-di-tert-butylphenyl) phosphite (Irganox 168), bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite (PEP-36), or 627A.

[0059] The thioester antioxidants are one or more of distearyl thiodipropionate, dilauryl thiodipropionate, or pentaerythritol tetrakis(3-laurylthiopropionate).

[0060] In the present invention, common lubricants can be selected, such as but not limited to one or more of vinyl bisstearamide, polysiloxane, calcium stearate, magnesium stearate, zinc stearate, PE wax, or PP wax.

[0061] In the present invention, common weathering agents can be selected, such as but not limited to hindered amine light stabilizers and benzotriazole ultraviolet light absorbers.

[0062] Specifically, the hindered amine light stabilizer is at least one of bis(2,2,6,6-tetramethylpiperidinol) sebacate, polymer of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and 2,4,6-trichloro-1,3,5-triazine.

[0063] Specifically, the benzotriazole ultraviolet light absorber is one or more of 2-(2'-hydroxy-5'-methylphenyl) benzotriazole (UV-P), 2-(2'-hydroxy-3',5'-bis(α,α-dimethylbenzyl)phenyl) benzotriazole (UV-234), 2-(2'-hydroxy-3-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole (UV-236).

[0064] The present invention also provides a preparation method of the above polypropylene composition, comprising the following steps:

[0065] S1. After mixing the components of the flame-retardant polypropylene particles evenly, melt-blend, pelletize and dry them using a twin-screw extruder to obtain flame-retardant polypropylene particles;

[0066] S2. Blend the flame-retardant polypropylene particles with a long glass fiber masterbatch to obtain the polypropylene composition.

[0067] Furthermore, the extruder is a twin-screw extruder.

[0068] Specifically, the temperature of the twin-screw extruder is preferably 150 - 160 °C in the first zone, 180 - 190 °C in the second zone, 210 - 230 °C in the third to fifth zones, and 200 - 210 °C at the die; the screw speed is 300 - 500 r / min; the vacuum degree is ≤ 0.1 MPa.

[0069] The present invention also protects the application of the above polypropylene composition in preparing materials for electronic and electrical housings, such as energy storage battery packs, power battery lithium battery covers, protection boxes for electrical and electronic circuit boards, etc.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] The present invention provides a polypropylene composition. By adjusting the melt flow rate of the polypropylene resin and combining with hyperbranched polyester and flow modifiers, the ablation resistance and exudation resistance of the material can be effectively improved, and it has good impact performance and flow performance. The ablation resistance is not less than 600 s, the exudation area grade is not higher than grade 2, and the helix length is not less than 1700 mm. Detailed Embodiments

[0072] The following further elaborates the present invention in conjunction with specific embodiments. The embodiments are only used to explain the present invention and are not used to limit the scope of the present invention. The test methods used in the following embodiments are conventional methods unless otherwise specified; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0073] 1. Raw materials used in each embodiment and comparative example:

[0074] Polypropylene resin:

[0075] Polypropylene resin 1: Block copolymerized polypropylene, PP K7100, with a melt flow rate of 110 g / 10 min measured at 230 °C under a load of 2.16 kg according to the ISO 1133-1:2022 standard, purchased from Sinopec Yanshan Petrochemical;

[0076] Polypropylene resin 2: Block copolymerized polypropylene, PP BX3910, with a melt flow rate of 80 g / 10 min measured at 230 °C under a load of 2.16 kg according to the ISO 1133-1:2022 standard, purchased from SK Geo Centric, South Korea;

[0077] Polypropylene resin 3: Block copolymerized polypropylene, PP BX3950, with a melt flow rate of 150 g / 10 min measured at 230 °C under a load of 2.16 kg according to the ISO 1133-1:2022 standard, purchased from SK Geo Centric, South Korea;

[0078] Polypropylene resin 4: Homopolypropylene, PP PPH-MN150, with a melt flow rate of 150 g / 10 min measured at 230 °C under a load of 2.16 kg according to the ISO 1133-1:2022 standard, purchased from Sinopec Luoyang Engineering Co., Ltd.;

[0079] Polypropylene resin 5: Block copolymerized polypropylene, PP EP548R, with a melt flow rate of 28 g / 10 min measured at 230 °C under a load of 2.16 kg according to the ISO 1133-1:2022 standard, purchased from CNOOC and Shell Petrochemicals Company Limited;

[0080] Piperazine salt:

[0081] Piperazine salt 1: Piperazine pyrophosphate, JNP-2, purchased from Sichuan Research and Design Institute of Fine Chemical Industry;

[0082] Piperazine salt 2: Piperazine phosphate, JNP-1, purchased from Sichuan Research and Design Institute of Fine Chemical Industry;

[0083] Melamine salt:

[0084] Melamine salt 1: Melamine polyphosphate, Melapur200-70, purchased from BASF SE;

[0085] Melamine salt 2: Melamine pyrophosphate, DMPY, purchased from Sichuan Research and Design Institute of Fine Chemical Industry;

[0086] Flame retardant synergist: Silicon dioxide, XFI05, purchased from Xianfeng Nano Materials Technology Co., Ltd.;

[0087] Long glass fiber masterbatch: GFPP-L50 (glass fiber content is 50wt%), purchased from Kingfa Sci & Tech Co., Ltd.;

[0088] Ceramic forming filler: Wollastonite, HG-400, purchased from Dalian Global Minerals Group;

[0089] Flux:

[0090] Flux 1: Nano sepiolite, CALY 20, purchased from Tolsa Group, Spain;

[0091] Flux 2: Low melting point glass powder, FR01, purchased from Guangzhou Gelinger New Materials Co., Ltd.;

[0092] Flow modifier:

[0093] Flow modifier 1: Polybutene-1, PB 0801M, the melt flow rate tested according to ISO 1133-1:2022 standard at 190℃ and 2.16 kg load is 200 g / 10 min;

[0094] Flow modifier 2: Polybutene-1, DP 8510M, the melt flow rate tested according to ISO 1133-1:2022 standard at 190℃ and 2.16 kg load is 40 g / 10 min;

[0095] Hyperbranched polyester:

[0096] Hyperbranched polyester 1: HBP-158, number average molecular weight 6000 g / mol, hydroxyl end group content is 70wt%, purchased from Wuhan Hyperbranched Resin Technology Co., Ltd.;

[0097] Hyperbranched resin 2: HyPer C100, with a number average molecular weight of 4000 g / mol and a terminal hydroxyl group content of 50 wt%, was purchased from Wuhan Hyperbranched Resin Technology Co., Ltd.;

[0098] Auxiliaries:

[0099] Antioxidant: A compound with a mass ratio of 1:1 of a hindered phenol antioxidant and a thioester antioxidant, both commercially available;

[0100] Lubricant: EBS B50, commercially available;

[0101] It should be noted that the same raw materials used in the parallel experiments of each example and comparative example in the present invention are from the same source.

[0102] 2. The polypropylene compositions described in each example and comparative example were prepared by the following method according to the formulations in Tables 1 to 4, including the following steps:

[0103] S1. After mixing the components in the flame-retardant polypropylene particles in a high-speed mixer for 1 to 3 minutes until evenly mixed, melt blending, pelletizing, and drying were carried out using a twin-screw extruder to obtain flame-retardant polypropylene particles; among them, the feeding speed of the twin-screw extruder was 250 to 350 rpm, and the specific extrusion temperatures were: the temperature of the first zone was 150 to 160 °C, the temperature of the second zone was 160 to 170 °C, the temperatures of the third to fifth zones were 180 to 190 °C, and the die temperature was 190 to 200 °C;

[0104] S2. The flame-retardant polypropylene particles were mixed evenly with the long glass fiber masterbatch to obtain the polypropylene composition.

[0105] 3. Performance testing:

[0106] (1) Ablation resistance performance test: The polypropylene compositions prepared in each example and comparative example were injection molded into square plates with dimensions of 100 mm * 100 mm * 2.0 mm. According to the ablation material test method of GJB323A-96, an oxy-acetylene flame was vertically impinged on the square plate, and the oxy-acetylene flame temperature was as high as 1300 °C. The material was burned through or ablated until 600 s;

[0107] (2) Impact performance test: The polypropylene compositions prepared in each example and comparative example were tested according to the ISO 180-2000 standard. The specimen size was 4 mm * 10 mm * 80 mm, with a Type A notch;

[0108] (3) Exudation performance test: Place a square plate of 100mm * 100mm * 2.0mm in a natural aging box (85 °C, 85% relative humidity) for 500h, observe the area of surface exudates. The larger the exudation area, the more serious the exudation. When the exudation area ≤ 10% is recorded as level 1; 10% < exudation area ≤ 40% is recorded as level 2; 40% < exudation area ≤ 60% is recorded as level 3; 60% < exudation area ≤ 90% is recorded as level 4; when the exudation area > 90% is recorded as level 5.

[0109] (4) Archimedes spiral length test: Use an Archimedes spiral mold with a thickness of 2.5mm. Set the temperature of a 120-ton injection molding machine at 230 °C, the injection pressure at 45%, the injection speed at 45%, and the mold temperature at 50 °C. Test the Archimedes spiral length of the polypropylene compositions prepared in each example and comparative example. The longer the length, the better the fluidity.

[0110] Examples 1 - 14 and Comparative Examples 1 - 4

[0111] Table 1 Dosages of each component of flame-retardant polypropylene particles in the polypropylene compositions in Examples 1 - 11 (unit: parts by weight)

[0112]

[0113]

[0114] Table 2 Dosages of each component of flame-retardant polypropylene particles in the polypropylene compositions in Examples 12 - 14 and Comparative Examples 1 - 4 (unit: parts by weight)

[0115]

[0116]

[0117] Table 3 Dosages (unit: weight percentage) and properties of components in the polypropylene compositions in Examples 1 - 11

[0118]

[0119]

[0120] Table 4 Dosages (unit: weight percentage) and properties of components in the polypropylene compositions in Examples 12 - 14 and Comparative Examples 1 - 4

[0121]

[0122]

[0123] The polypropylene compositions prepared in the embodiments of the present invention have good ablation resistance, exudation properties, good fluidity and mechanical properties. Specifically, the ablation resistance is not less than 600 s, the exudation area grade is not higher than grade 2, and the helix length is not less than 1700 mm.

[0124] As can be seen from Comparative Example 1, when the melt flow rate of the polypropylene resin used is too low, the exudation properties of the prepared polypropylene composition significantly decrease.

[0125] As can be seen from Comparative Examples 2 and 3, if the flow modifier or hyperbranched polyester is not added, the exudation properties of the polypropylene composition cannot be well improved.

[0126] As can be seen from Comparative Example 4, if a conventional lubricant is used instead of the hyperbranched polyester in the present invention, the compatibility between the flame retardant and the resin cannot be enhanced, but the exudation properties will decrease instead. Continuing to increase its dosage cannot improve the exudation properties.

[0127] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A polypropylene composition, characterized in that The polypropylene composition comprises, by mass percentage: 72-88% flame retardant polypropylene particles and 12-28% long glass fiber masterbatch; The flame retardant polypropylene particles include the following components calculated in parts by weight: The melt flow rate of the polypropylene resin at 230° C. and 2.16 kg is not less than 50 g / 10 min.

2. The polypropylene composition according to claim 1, characterized in that The helical length of the polypropylene composition is not less than 1700 mm, preferably 1700 to 2300 mm.

3. The polypropylene composition according to claim 1, characterized in that: The flow modifier has a melt flow rate of 30 to 300 g / 10 min at 190° C. and a load of 2.16 kg.

4. The polypropylene composition according to claim 1, characterized in that: The flow improver is polybutene-1.

5. The polypropylene composition according to claim 1, characterized in that: The piperazine salt includes one or more of piperazine phosphate, piperazine pyrophosphate or piperazine polyphosphate.

6. The polypropylene composition according to claim 1, characterized in that: The melamine salt includes one or more of melamine phosphate, melamine pyrophosphate or melamine polyphosphate.

7. The polypropylene composition according to claim 1, characterized in that: The content of long glass fibers in the long glass fiber masterbatch is 30-60 wt %.

8. The polypropylene composition according to claim 1, characterized in that: The flame retardant polypropylene particles also include 0.1 to 5 parts of auxiliary agents.

9. A method for preparing the polypropylene composition according to any one of claims 1 to 8, characterized in that: The steps include: S1. After the components of the flame-retardant polypropylene particles are uniformly mixed, melt blending, granulation, and drying are performed using a twin-screw extruder to obtain flame-retardant polypropylene particles; S2. Blending the flame retardant polypropylene particles with the long glass fiber masterbatch to obtain a polypropylene composition.

10. Use of the polypropylene composition according to any one of claims 1 to 8 in the preparation of electronic and electrical materials.

Images