Polypropylene composition, process for its preparation and use thereof

Abstract

The application belongs to the field of polypropylene, and specifically discloses a polypropylene composition, a preparation method and application thereof.The polypropylene composition comprises the following components in parts by weight: 68-102 parts of copolymerized polypropylene, 4.5-31 parts of polytetrahydrofuran ether glycol, 0.01-0.6 parts of an antioxidant, and 0.07-0.9 parts of hexafluorobisphenol A.The polypropylene composition has improved high-temperature creep resistance and cracking problems through the combination of polytetrahydrofuran ether glycol and dihexafluorobisphenol A.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polypropylene, and particularly relates to a polypropylene composition and a preparation method and application thereof. BACKGROUND

[0002] The automobile bellows is mainly used for the automobile cooling system, which is located near the engine, so the temperature is high, and it is required to have good aging performance. At the same time, due to the existence of the coolant in the automobile cooling system, it is often in a certain pressure state, which requires the automobile bellows material to have good high-temperature creep resistance. The automobile bellows is generally a three-layer co-extrusion material, the outermost layer is PA612, the middle layer is an adhesive layer, and the inner layer is a PP layer. Since it is located in the cooling system, the major automobile manufacturers require that after adding coolant in the cooling pipeline, the automobile bellows does not crack under high temperature and high pressure.

[0003] Patent document CN113549291A discloses a creep-resistant polypropylene and a preparation method thereof, which improves the creep resistance by adding inorganic creep-resistant modifiers and polytetrafluoroethylene, and the creep resistance is reduced from 12.3% to 5.5%. Chinese patent document CN102532701A discloses a low-warp, creep-resistant polypropylene composition and a preparation method thereof, which involves the use of a compatibilizer and a nucleating agent to improve the creep resistance of polypropylene and improve the warp performance. Patent document CN105504500A discloses a creep-resistant polypropylene composite material and a preparation method thereof, which improves the crosslinking degree of polypropylene by adding a cooling master batch, thereby improving the creep resistance. The above-mentioned creep resistance is only the normal temperature creep resistance, and there is no research on the high and low temperature creep resistance, so the application range is greatly limited, and it cannot meet the specific requirements of the automobile bellows for crack resistance. SUMMARY

[0004] In view of the poor high-temperature creep resistance and crack resistance of the existing PP composite material, the present application provides a polypropylene composition and a preparation method and application thereof.

[0005] To achieve the above-mentioned purpose, the following technical solutions are specifically included:

[0006] A polypropylene composition, comprising the following components in parts by weight: copolymerized polypropylene 68-102 parts, polytetrahydrofuran ether diol 4.5-31 parts, antioxidant 0.01-0.6 parts, and hexafluorobisphenol A 0.07-0.9 parts.

[0007] The polypropylene composition contains polytetrahydrofuran ether glycol, which contains hydroxyl groups at both ends of the molecular chain and ether bonds on the skeleton, and after the internal skeleton ether bonds are broken after the addition of the substance, crosslinking points can be provided for polypropylene, so that the polypropylene molecules become a network structure, and the creep performance is improved; and contains hexafluorobisphenol A, which has hydroxyl groups and good resistance to precipitation, and as a component of auxiliary antioxidant, the aging performance of the material can be ensured; the combination of polytetrahydrofuran ether glycol and hexafluorobisphenol A improves the cracking problem of the polypropylene composition cooling pipe.

[0008] As a preferred embodiment of the present application, the polypropylene composition includes the following components by weight: copolymerized polypropylene 70-100 parts, polytetrahydrofuran ether glycol 5-30 parts, antioxidant 0.1-0.5 parts, and hexafluorobisphenol A 0.1-0.8 parts.

[0009] The weight parts of the copolymerized polypropylene can be 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, and specific point values between the above point values, and due to the consideration of space and simplicity, the present application does not exhaustively list the specific point values included in the range.

[0010] As a preferred embodiment of the present application, the melt mass flow rate of the copolymerized polypropylene is 0.2-4 g / 10 min under the condition of 230℃ and 2.16 Kg load according to ISO1133-2011.

[0011] As a further preferred embodiment of the present application, the melt mass flow rate of the copolymerized polypropylene is 0.5-3 g / 10 min under the condition of 230℃ and 2.16 Kg load according to ISO1133-2011.

[0012] As a preferred embodiment of the present application, the mass percentage content of the copolymerized polypropylene in the polypropylene composition is not less than 60%.

[0013] As a preferred embodiment of the present application, the number average molecular weight of the polytetrahydrofuran ether glycol is 1000-2300.

[0014] As a further preferred embodiment of the present application, the number average molecular weight of the polytetrahydrofuran ether glycol is 1800-2000.

[0015] As a further preferred embodiment of the present application, the weight parts of the polytetrahydrofuran ether glycol are 10-20 parts.

[0016] The weight parts of the polytetrahydrofuran ether glycol can be 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, and specific point values between the above point values. Due to the limitation of the length and for the sake of simplicity, the present application will not list the specific point values included in the range.

[0017] As a preferred embodiment of the present application, the antioxidant includes at least one of tris[2.4-di-tert-butylphenyl] phosphite (168), pentaerythritol tetra-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (1010), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (3114), and pentaerythritol tetra(3-laurylthiopropionate) (412S).

[0018] As a further preferred embodiment of the present application, the antioxidant is tris[2.4-di-tert-butylphenyl] phosphite (168) and pentaerythritol tetra-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (1010), or 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (3114) and pentaerythritol tetra(3-laurylthiopropionate) (412S); the mass ratio of tris[2.4-di-tert-butylphenyl] phosphite (168) and pentaerythritol tetra-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (1010) is 1:(0.9-1.1); the mass ratio of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate (3114) and pentaerythritol tetra(3-laurylthiopropionate) (412S) is 1:(0.9-1.1).

[0019] The weight parts of the hexafluorobisphenol A can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.65, 0.7, 0.75, 0.8, and specific point values between the above point values. Due to the limitation of the length and for the sake of simplicity, the present application will not list the specific point values included in the range.

[0020] As a further preferred embodiment of the present application, the weight parts of the hexafluorobisphenol A is 0.2-0.5 parts.

[0021] A preparation method of a polypropylene composition, comprising the following steps: sequentially mixing and uniformly mixing, melt kneading, and extruding and granulating copolymerized polypropylene resin, polytetrahydrofuran ether glycol, antioxidant, and hexafluorobisphenol A to obtain the polypropylene composition.

[0022] As a preferred embodiment of the present application, the temperature of the melt kneading is 180-220℃.

[0023] As a preferred embodiment of the present application, the rotation speed of the melt mixing is 450-500 rpm.

[0024] Use of a polypropylene composition in the manufacture of an automotive bellows, the polypropylene composition meeting the requirements of automotive bellows for crack resistance.

[0025] Compared with the prior art, the present application has the following beneficial effects: the present application improves the high-temperature creep resistance and cracking problems of the polypropylene composition by combining both polytetrahydrofuran ether glycol and dihexafluorobisphenol A. DETAILED DESCRIPTION

[0026] In order to better illustrate the purpose, technical scheme and advantages of the present application, the present application will be further described below through specific examples. The test methods used in the examples and / or comparative examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are commercially available unless otherwise specified.

[0027] PP 3010: melt mass flow rate 1.2 g / 10 min, purchased from Taiwan Chemical Fiber Co., Ltd. of China;

[0028] PP R4220: melt mass flow rate 0.5 g / 10 min, purchased from Yanshan Petrochemical;

[0029] PP K8003: melt mass flow rate 3.0 g / 10 min, purchased from Yanshan Petrochemical.

[0030] PTMEG P1000: polytetrahydrofuran ether glycol, number average molecular weight 1000, purchased from BASF;

[0031] PTMEG P1800: polytetrahydrofuran ether glycol, number average molecular weight 1800, purchased from BASF;

[0032] PTMEG P2000: polytetrahydrofuran ether glycol, number average molecular weight 2000, purchased from BASF;

[0033] Primary antioxidant 1010: purchased from BASF;

[0034] Primary antioxidant 3114: purchased from Tianjin Li'anlong New Material Co., Ltd.;

[0035] Secondary antioxidant 168: purchased from BASF;

[0036] Secondary antioxidant 412S: purchased from Aidi Ke;

[0037] Hexafluorobisphenol A: antioxidant auxiliary agent, purchased from BASF.

[0038] Examples 1-17 and Comparative Examples 1-3

[0039] A polypropylene composition, comprising the following steps:

[0040] (1) Put copolymerized polypropylene resin, polytetramethylene ether glycol, antioxidant and hexafluorobisphenol A into a high-speed mixer according to the raw material ratio in Table 1 and mix uniformly;

[0041] (2) Then add into a twin-screw extruder, melt mix and extrude granulation under the temperature of 180-220 ℃ and the screw rotation speed of 450-500 rpm to obtain the polypropylene composition.

[0042] Table 1 (parts by weight)

[0043]

[0044]

[0045] Each performance evaluation method:

[0046] (1) High-temperature creep (strain) performance evaluation method: test the sample at the temperature of 100 ℃, select the stress of 10 MPa, carry out for 200 h according to the stress, and record the strain amount, and the lower the strain amount, the better the creep resistance performance is;

[0047] (2) Part cracking performance evaluation method: extrude the corresponding material of the above examples and the comparative examples into a corrugated pipe, and arrange to carry out the test under the pressure of 1 Bar at 100 ℃, record the part cracking time, and the longer the cracking time is, the better the cracking resistance performance is.

[0048] Table 2

[0049]

[0050] It can be known from the examples that the strain amount of the polypropylene composition of the present application reaches 2.7-3.9%, and the cracking time reaches 710-910 h.

[0051] It can be known from Examples 2, 1 and 3 that with the increase of the melt mass flow rate of PP (0.5, 1.2, 3.0 g / 10 min), the strain amount of the polypropylene composition gradually increases, and the cracking time gradually decreases, and the comprehensive performance of the polypropylene composition is better when the melt mass flow rate of PP is 0.5-3.0 g / 10 min.

[0052] It can be known from Examples 4, 2 and 5 that with the increase of the molecular weight of polytetramethylene ether glycol (1000, 1800, 2000), the strain amount of the polypropylene composition gradually decreases, and the cracking time gradually increases, and the greater the number average molecular weight of polytetramethylene ether glycol is, the better the creep resistance and cracking resistance performance of the polypropylene composition is.

[0053] From the examples 6, 2, 7, 8, 9, it can be seen that with the increase of the addition amount of polytetrahydrofuran ether glycol (5, 10, 15, 20, 30 parts), the strain of the polypropylene composition gradually decreases and tends to be constant, and the cracking time gradually increases and tends to be constant. The comprehensive performance of the polypropylene composition is relatively optimal when the addition amount of polytetrahydrofuran ether glycol is 5-20 parts.

[0054] From the examples 2, 10, it can be seen that in the case of adding hexafluorobisphenol A, the comprehensive performance of the polypropylene composition prepared by the complexing of the main antioxidant 3114 and the auxiliary antioxidant 412S is better than that of the complexing of the main antioxidant 1010 and the auxiliary antioxidant 168.

[0055] From the examples 11, 2, 12, 13, it can be seen that with the increase of the addition amount of hexafluorobisphenol A (0.1, 0.2, 0.5, 0.8 parts), the strain of the polypropylene composition gradually decreases and tends to be constant, and the cracking time gradually increases and tends to be constant. The comprehensive performance of the polypropylene composition is relatively optimal when the addition amount of hexafluorobisphenol A is 0.2-0.5 parts.

[0056] From the examples 2 and the comparative examples 1, 2 and 3, it can be seen that the high-temperature creep resistance and cracking problems of the polypropylene composition are improved by the combination of polytetrahydrofuran ether glycol and dihexafluorobisphenol A.

[0057] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A polypropylene composition, characterized in that, The product comprises the following components in parts by weight: 68-102 parts of copolymer polypropylene, 4.5-31 parts of polytetrahydrofuran ether glycol, 0.01-0.6 parts of antioxidant, and 0.07-0.9 parts of hexafluorobisphenol A; the copolymer polypropylene has a melt flow rate of 0.2-4 g / 10 min tested at 230°C and 2.16 kg load according to ISO 1133-2011; and the polytetrahydrofuran ether glycol has a number average molecular weight of 1000-2300.

2. The polypropylene composition according to claim 1, characterized in that, The number-average molecular weight of the polytetrahydrofuran ether diol is 1800-2000.

3. The polypropylene composition according to claim 1, characterized in that, The polytetrahydrofuran ether diol is present in parts by weight of 10-20.

4. The polypropylene composition according to claim 1, characterized in that, The hexafluorobisphenol A is present in an amount of 0.2-0.5 parts by weight.

5. The polypropylene composition according to claim 1, characterized in that, The antioxidants include at least one of tris[2,4-di-tert-butylphenyl] phosphite, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, and pentaerythritol tetrakis(3-lauryl thiopropionate).

6. The polypropylene composition according to claim 1, characterized in that, The antioxidant is tris[2,4-di-tert-butylphenyl]phosphite and pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, or 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid and pentaerythritol tetrakis(3-lauryl thiopropionate).

7. A method for preparing the polypropylene composition according to any one of claims 1-6, characterized in that, The process includes the following steps: mixing copolymer polypropylene resin, polytetrahydrofuran ether glycol, antioxidant and hexafluorobisphenol A in sequence, followed by melt mixing, extrusion granulation, to obtain the polypropylene composition.

8. The use of a polypropylene composition according to any one of claims 1-6 in the preparation of automotive bellows.

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