Halogen-free ablation-resistant polypropylene resin composition and use thereof

Abstract

Provided is a halogen-free ablation-resistant polypropylene resin composition, comprising the following components in parts by weight: 18-50 parts of a polypropylene resin, 3-10 parts of a piperazine flame retardant, 20-26 parts of a nitrogen-phosphorus composite flame retardant, 0.2-1.8 parts of a flame retardant synergist, and 12-28 parts of a long glass fiber, wherein the mass percentage of silicon dioxide in the long glass fiber is greater than 60%. The halogen-free ablation-resistant polypropylene resin composition has excellent burn-through resistance and heat-insulation properties, and has good flame-retardant properties.

Description

Halogen-free ablative polypropylene resin composition and application thereof TECHNICAL FIELD

[0001] The application belongs to the technical field of materials for battery pack upper covers, and particularly relates to a halogen-free ablative polypropylene resin composition and application thereof. BACKGROUND

[0002] With the vigorous development of the new energy industry, the installed capacity of power batteries and energy storage batteries is continuously increasing. Among them, the materials for battery pack upper covers are mainly metals or thermosetting materials, and the scheme has the disadvantages of large proportion, low processing efficiency and environmental pollution. With the continuous promotion of the national double carbon policy, thermoplastic materials are rapidly popularized and applied due to their light weight and green environmental protection advantages.

[0003] The core requirement of a battery pack is to pass the GB / T31467.3-2015 fire resistance test, and it is required that no large amount of toxic and harmful gases are generated during the combustion process. Conventional polypropylene materials (PP) cannot meet the existing requirements, and a new generation of low smoke, halogen-free, ablative and heat-insulating flame-retardant reinforced PP that meets the test requirements of customers will become the trend of technological development. In related technologies, halogen-free piperazine flame retardants, long glass fibers and ceramic fillers are compounded to have a certain ablative effect, but after thinning, the material is not resistant to fire and has the problem of easy burning through.

[0004] Therefore, it is an urgent problem in the art to develop a polypropylene resin material that still has excellent ablative performance, heat-insulating performance and flame-retardant performance after thinning. SUMMARY

[0005] The following is a summary of the subject matter of the detailed description. This summary is not intended to limit the scope of the claims.

[0006] The application provides a halogen-free ablative polypropylene resin composition and application thereof; the halogen-free ablative polypropylene resin composition has excellent burn-through resistance and heat-insulating performance, and good flame-retardant performance.

[0007] In a first aspect, the application provides a halogen-free ablative polypropylene resin composition, which comprises, in parts by weight, 18-50 parts of a polypropylene resin, 3-10 parts of a piperazine flame retardant, 20-26 parts of a nitrogen-phosphorus composite flame retardant, 0.2-1.8 parts of a synergistic flame retardant, and 12-28 parts of long glass fibers; the long glass fibers have a mass percentage of silicon dioxide of >60%.

[0008] In the present application, the specific content of piperazine flame retardant and nitrogen-phosphorus composite flame retardant is compounded, which is beneficial to increase the thickness and density of carbon layer, improve the heat insulation performance; adding a specific content of synergistic flame retardant for compounding, further improving the heat insulation performance of the material; adding specific long glass fiber can enhance the skeleton strength and improve the ablation resistance; long glass fiber is compounded with specific flame retardant and synergistic flame retardant, so that the halogen-free ablation-resistant polypropylene resin composition has excellent ablation resistance and heat insulation performance, and good flame retardant performance.

[0009] The 18-50 parts of polypropylene resin may be, for example, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts or 50 parts, etc.

[0010] The 3-10 parts of piperazine flame retardant may be, for example, 3 parts, 3.2 parts, 3.4 parts, 3.6 parts, 3.8 parts, 4 parts, 4.2 parts, 4.4 parts, 4.6 parts, 4.8 parts, 5 parts, 5.2 parts, 5.5 parts, 5.8 parts, 6 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7 parts, 7.2 parts, 7.5 parts, 7.8 parts, 8 parts, 8.2 parts, 8.5 parts, 8.8 parts, 9 parts, 9.2 parts, 9.5 parts, 9.8 parts or 10 parts, etc.

[0011] The 20-26 parts of nitrogen-phosphorus composite flame retardant may be, for example, 20 parts, 20.5 parts, 21 parts, 21.5 parts, 22 parts, 22.5 parts, 23 parts, 23.5 parts, 24 parts, 24.5 parts, 25 parts, 25.5 parts or 26 parts, etc.

[0012] The 0.2-1.8 parts of synergistic flame retardant may be, for example, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 parts, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts or 1.8 parts, etc.

[0013] The 12-28 parts of long glass fiber may be, for example, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts or 28 parts, etc.

[0014] The mass percentage of silicon dioxide in the long glass fiber is >60%, for example, it may be 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69% or 70%, etc.

[0015] In the present application, the silica content in the long glass fiber can be determined by a conventional method in the related art, such as according to the method of GB / T 1549-2008 Fiber Glass Chemical Analysis.

[0016] In the present application, the long glass fiber further comprises, in terms of mass percentage, 10-20% alumina (for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%, etc.), 5-15% boron oxide (for example, it can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, or 15%, etc.), 12-22% calcium oxide (for example, it can be 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or 22%, etc.), 2-8% magnesium oxide (for example, it can be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, or 8%, etc.), and 0-0.5% sodium oxide (for example, it can be 0%, 0.1%, 0.2%, 0.3%, 0.4%, or 0.5%, etc.).

[0017] Preferably, the polypropylene resin has a melt index of 10-32 g / 10 min, for example, it can be 10 g / 10 min, 12 g / 10 min, 14 g / 10 min, 16 g / 10 min, 18 g / 10 min, 20 g / 10 min, 22 g / 10 min, 24 g / 10 min, 26 g / 10 min, 28 g / 10 min, 30 g / 10 min, or 32 g / 10 min, etc.

[0018] In the present application, the test conditions for the melt index of the polypropylene resin are 230°C and 2.16 kg.

[0019] Preferably, the piperazine flame retardant comprises any one or a combination of at least two of piperazine phosphate, piperazine pyrophosphate, or piperazine polyphosphate.

[0020] Preferably, the nitrogen-phosphorus composite flame retardant comprises melamine pyrophosphate and / or melamine polyphosphate.

[0021] Preferably, the mass ratio of the melamine pyrophosphate and the melamine polyphosphate is (0.3-3):1, wherein the specific value in (0.3-3) can be 0.3, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, or 3, etc.; and further preferably (1-2.6):1.

[0022] Preferably, the synergistic flame retardant comprises at least two of zinc oxide, zinc borate, glass powder or sepiolite, further preferably a combination of zinc oxide and zinc borate, or a combination of sepiolite and zinc borate.

[0023] Preferably, the synergistic flame retardant comprises at least two of zinc oxide, sepiolite and zinc borate, further preferably a combination of zinc oxide and zinc borate, or a combination of sepiolite and zinc borate.

[0024] Preferably, the mass ratio of zinc oxide and zinc borate, or the mass ratio of sepiolite and zinc borate is independently (0.5-4.2):1, wherein the specific value in (0.5-4.2) can be 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4 or 4.2, etc., further preferably (1.2-4):1.

[0025] Preferably, the average retention length of the long glass fiber is >1mm, for example, 1, 1.05mm, 1.1mm, 1.15mm, 1.2mm, 1.25mm, 1.3mm, 1.35mm, 1.4mm, 1.45mm, 1.5mm, 1.55mm, 1.6mm, 1.65mm, 1.7mm, 1.75mm, 1.8mm, 1.85mm, 1.9mm, 1.95mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.2mm, 4.5mm, 4.8mm or 5mm, etc., further preferably 1.2-3mm.

[0026] In the present application, the factors affecting the average retention length of the long glass fiber include the type of long glass fiber (including the content of silicon dioxide) and the injection molding conditions (such as injection pressure or back pressure), etc.

[0027] Preferably, the mass percentage of silicon dioxide in the long glass fiber is 65-70%.

[0028] Preferably, the long glass fiber is added in the form of long glass fiber masterbatch.

[0029] In the present application, the long glass fiber masterbatch comprises resin and long glass fiber; the resin comprises polyolefin; the polyolefin comprises polypropylene.

[0030] Preferably, the long glass fiber in the long glass fiber master batch has a mass percentage of 40-60%, for example, 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, or 60%, etc.

[0031] Preferably, the halogen-free ablative polypropylene resin composition further comprises 1-5 parts of a compatibilizer, for example, 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, etc.

[0032] Preferably, the compatibilizer comprises polypropylene grafted maleic anhydride (PP-g-MAH) and / or polyolefin elastomer grafted maleic anhydride.

[0033] In the present application, the polyolefin elastomer grafted maleic anhydride comprises ethylene-octene copolymer grafted maleic anhydride (POE-g-MAH).

[0034] Preferably, the halogen-free ablative polypropylene resin composition further comprises 0.3-1.5 parts of other additives, for example, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, or 1.5 parts, etc.

[0035] Preferably, the other additives comprise an antioxidant and / or a lubricant.

[0036] In the present application, the antioxidant comprises, but is not limited to, at least one of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester (antioxidant 1010), tri[2.4-di-tert-butylphenyl]phosphite (antioxidant 168), n-octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), 4,4'-bis(α,α-dimethylbenzyl) diphenylamine (antioxidant 445), or N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine (antioxidant 1098).

[0037] In the present application, the lubricant comprises, but is not limited to, at least one of ethylene bis-stearamide, erucamide, zinc stearate, or silicone oil.

[0038] In the present application, the halogen-free ablative polypropylene resin composition, after being made into a thin-walled product, still has excellent ablative resistance, solving the problem of easy burning through of conventional polypropylene composites after thinning.

[0039] In the present application, the thin-walled refers to a thickness of the product as low as 2 mm, for example, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, or 2 mm, etc.

[0040] In a second aspect, the present application provides an article comprising the halogen-free ablative-resistant polypropylene resin composition of the first aspect, wherein the article comprises a battery pack upper cover.

[0041] The numerical ranges recited herein are inclusive of the endpoints and also include any other ranges that fall within the recited ranges, which are limited only by the inclusion of endpoints. For simplicity, the ranges are not listed with every possible combination of endpoints.

[0042] Compared with the related art, the present application has the following beneficial effects:

[0043] The halogen-free ablative-resistant polypropylene resin composition provided by the present application uses specific contents of piperazine flame retardant, nitrogen-phosphorus composite flame retardant, synergistic flame retardant, and specific long glass fiber compound, and the obtained composition is particularly suitable for preparing thin-walled polypropylene materials, and improves the burn-through resistance, heat insulation performance, and flame retardant performance of the thin-walled polypropylene materials.

[0044] Other aspects can become apparent from the following detailed description. DETAILED DESCRIPTION

[0045] The technical solutions of the present application are further illustrated by the specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application, and should not be regarded as specific limitations of the present application.

[0046] The materials used in the present application are as follows:

[0047] Resin

[0048] PP-1: homopolymer polypropylene pellets, brand HP500N, CNOOC Shell;

[0049] PP-2: copolymer polypropylene pellets, brand EP548R, CNOOC Shell;

[0050] Long glass fiber masterbatch (the resin in the long glass fiber masterbatch is polypropylene)

[0051] GF-1: the mass percentage content of long glass fiber is 50%; the long glass fiber includes, in terms of mass percentage content: 62% silicon dioxide, 15% aluminum oxide, 6% boron oxide, 13% calcium oxide, 3.6% magnesium oxide, and 0.4% sodium oxide;

[0052] GF-2: the mass percentage content of long glass fiber is 50%; the long glass fiber includes, in terms of mass percentage content: 68% silicon dioxide, 11% aluminum oxide, 6.5% boron oxide, 12% calcium oxide, 2.2% magnesium oxide, and 0.3% sodium oxide;

[0053] GF-d1: 50% by mass of long glass fiber; the long glass fiber includes, by mass percent: 50% of silicon dioxide, 16% of aluminum oxide, 6.8% of boron oxide, 21.5% of calcium oxide, 5.5% of magnesium oxide, and 0.2% of sodium oxide;

[0054] Antioxidant: Antioxidant 1010, commercially available; Antioxidant 168, commercially available, in a mass ratio of 1:1;

[0055] Lubricant: Ethylene bis-stearamide EBS, commercially available;

[0056] Melamine pyrophosphate: purchased from Hubei Xinmingtai Chemical Co., Ltd.;

[0057] Melamine polyphosphate: purchased from Wuhan Jixingyibang Biological Technology Co., Ltd.;

[0058] Sepiolite: purchased from Yitian Mining Industry;

[0059] PP-g-MAH: Xingyuan Chemical, XYJ1210;

[0060] POE-g-MAH: Dow Chemical, AMPLIFY GR216;

[0061] Piperazine pyrophosphate, piperazine phosphate, triphenyl phosphate, zinc oxide, and zinc borate can be purchased commercially.

[0062] Examples 1-14 and Comparative Examples 1-6 provide a halogen-free ablative polypropylene resin composition, the formulation of which is shown in Tables 1 and 2, in parts by weight, wherein " / " indicates that the component is not included in the formulation.

[0063] Table 1

[0064] Table 2

[0065] Performance Test

[0066] The halogen-free ablative polypropylene resin compositions provided by Examples 1-14 and Comparative Examples 1-6, which are suitable for thin-walled injection molding, were thin-walled injection molded into polypropylene resin materials with a thickness of 1.5 mm, and the relevant properties thereof were tested; the specific process of the thin-walled injection molding included: an injection molding temperature of 210°C, a mold temperature of 30°C, and a back pressure of 0 bar.

[0067] (1) Flame-retardant property: reference to UL 94, vertical burning of 1.5 mm flame-retardant samples;

[0068] (2) Average fiber retention length: 1.5mm square plate of injection molding, ash after testing at 800℃ for 2h, secondary microscopic test of glass fiber average retention length;

[0069] (3) Burn-through resistance: 1000℃ flame, 1.5mm square plate is burned for 10min. Observe whether the square plate is burned through;

[0070] (4) Heat insulation performance: 1000℃ flame, 1.5mm square plate is burned, at the same time, test the temperature of the back of the square plate (the other side away from the flame), the smaller the temperature, the better the heat insulation performance.

[0071] The specific test results are shown in Table 3.

[0072] Table 3

[0073] As can be seen from Table 3, the halogen-free ablation-resistant polypropylene resin composition provided by the application is compounded with piperazine flame retardant, nitrogen-phosphorus composite flame retardant, synergistic flame retardant and specific long glass fiber in a specific content, and the obtained composition is especially suitable for preparing thin-walled polypropylene material, and improves the burn-through resistance, heat insulation performance and flame retardant performance of the thin-walled polypropylene material; in the application, the polypropylene material including the halogen-free ablation-resistant polypropylene resin composition has a V-0 level of flame retardant grade at a relatively thin thickness (1.5mm), a long average fiber retention length, good burn-through resistance, a back temperature rise of not higher than 255℃ and good heat insulation effect.

[0074] The above specific embodiments further specifically describe the purpose, technical solutions and beneficial effects of the application, and it should be understood that the above description is only for specific embodiments of the application and is not used to limit the application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application should be included in the protection scope of the application.

Claims

1. A halogen-free ablative polypropylene resin composition comprising, in parts by weight, 18-50 parts of a polypropylene resin, 3-10 parts of a piperazine flame retardant, 20-26 parts of a nitrogen-phosphorus compound flame retardant, 0.2-1.8 parts of a synergistic flame retardant, and 12-28 parts of long glass fibers. The long glass fibers have a mass percentage of silica > 60%.

2. The halogen-free ablative polypropylene resin composition according to claim 1, wherein, The polypropylene resin has a melt index of 10-32 g / 10 min.

3. The halogen-free ablative polypropylene resin composition according to claim 1 or 2, wherein, The polypropylene resin comprises a homopolymer polypropylene and / or a copolymer polypropylene.

4. The halogen-free ablative polypropylene resin composition according to any one of claims 1 to 3, wherein, The piperazine flame retardant comprises any one or a combination of at least two of piperazine phosphate, piperazine pyrophosphate, or piperazine polyphosphate.

5. The halogen-free ablative polypropylene resin composition according to any one of claims 1 to 4, wherein, The nitrogen-phosphorus compound flame retardant comprises melamine pyrophosphate and / or melamine polyphosphate. Preferably, the mass ratio of the melamine pyrophosphate and the melamine polyphosphate is (0.3-3): 1, further preferably (1-2.6):

1.

6. The halogen-free ablative polypropylene resin composition according to any one of claims 1 to 5, wherein The synergistic flame retardant comprises any one or a combination of at least two of zinc oxide, zinc borate, glass powder, or sepiolite. Preferably, the synergistic flame retardant comprises at least two of zinc oxide, sepiolite, and zinc borate, further preferably a combination of zinc oxide and zinc borate, or a combination of sepiolite and zinc borate. Preferably, the mass ratio of the zinc oxide and the zinc borate and the mass ratio of the sepiolite and the zinc borate are each independently (0.5-4.2): 1, further preferably (1.2-4):

1.

7. The halogen-free ablative polypropylene resin composition according to any one of claims 1 to 6, wherein The long glass fibers have an average retention length > 1 mm, further preferably 1.2-3 mm. Preferably, the long glass fibers have a mass percentage of silica of 65-70%.

8. The halogen-free ablative polypropylene resin composition according to any one of claims 1 to 7, wherein The long glass fibers are added in the form of long glass fiber masterbatch. Preferably, the long glass fiber masterbatch has a mass percentage of long glass fibers of 40-60%.

9. The halogen-free ablative polypropylene resin composition according to any one of claims 1 to 8, wherein, The halogen-free ablative polypropylene resin composition further comprises, in parts by weight, 1-5 parts of a compatibilizer.

10. The halogen-free ablative polypropylene resin composition according to claim 9, wherein, The compatibilizer comprises polypropylene grafted maleic anhydride and / or polyolefin elastomer grafted maleic anhydride.

11. The halogen-free ablative-resistant polypropylene resin composition according to any one of claims 1 to 10, wherein, The halogen-free ablative polypropylene resin composition further comprises, in parts by weight, 0.3-1.5 parts of other auxiliary agents.

12. The halogen-free ablative polypropylene resin composition of claim 11, wherein, The other auxiliary agents comprise an antioxidant and / or a lubricant.

13. An article comprising the halogen-free ablative polypropylene resin composition of any one of claims 1-12, which comprises a battery pack upper cover.

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