Polypropylene composition, polypropylene material and power cable protection pipe

Abstract

The present invention relates to the field of polypropylene materials, and in particular to a polypropylene composition, a polypropylene material and a power cable protection conduit. The polypropylene composition contains a polypropylene base resin, an antioxidant, an α-crystal nucleating agent, an optional light stabilizer and a masterbatch; the polypropylene base resin contains homopolymerized polypropylene and ethylene-propylene random copolymerized polypropylene. The power cable protection conduit made of the polypropylene composition or polypropylene material provided by the present invention has the characteristics of high tensile strength, high bending strength, high external pressure resistance, high toughness and high heat resistance.

Description

Technical Field

[0001] The invention relates to the field of polypropylene materials, and in particular to a polypropylene composition, a polypropylene material prepared from the composition, and a power cable protection pipe made from the polypropylene composition or the polypropylene material. Background Art

[0002] In the application of power cable protection pipes, pipes produced from polypropylene are superior to traditional pipes such as metal, ceramic and cement because of their light weight, good processability, convenient and reliable connection, service life and comprehensive cost advantages. Such pipes can ensure the high functional safety of municipal power cables for a long time.

[0003] As society's requirements for the environment continue to increase, more and more power cables are laid underground using trenchless methods, which is beneficial to beautify the environment and reduce production costs. Trenchless pipeline laying technology is a process that does not require a large amount of mud, soil, or road damage, and has good application prospects in the field of power cable laying projects in roads, railways, buildings, riverbeds, etc.

[0004] Trenchless power cable protection conduits have high requirements for tensile strength, impact strength and ring stiffness, that is, they are required to have excellent rigidity and toughness balance. Due to the limitations of structural performance characteristics, the rigidity and toughness balance of polypropylene resin has always been a difficult contradiction to overcome. Therefore, it is difficult to manufacture power cable protection conduits with excellent tensile strength, external pressure resistance, good low-temperature toughness and heat resistance with existing technical products.

[0005] CN102964689A discloses a modified polypropylene corrugated pipe and a manufacturing method thereof. The corrugated pipe is made of modified polypropylene material, and the modified polypropylene material is made of polypropylene base material, polytetrafluoroethylene, calcium stearate, antioxidant, pigment, etc. The modified polypropylene corrugated pipe of the present invention has excellent flame retardant performance, excellent electrical insulation, good impact resistance, relatively high heat deformation temperature, good low-temperature impact resistance, light weight, smooth surface, small friction resistance when passing cables, and can be hot-melt welded and butted, so it is suitable for laying pipelines and cables underground, and is widely used in telecommunications, power and other projects. However, the patent does not specify whether the relevant performance of the prepared modified polypropylene corrugated pipe can meet the requirements of the power industry standard DL / T802.7-2010.

[0006] CN107189318A discloses a special material for power cable sheath pipe and its preparation method. The special material composition system includes polypropylene matrix resin, reinforcing masterbatch, compatibilizer, nucleating agent, antioxidant, impact-resistant component, etc. It is reported that the composition system can meet the technical indicators of high temperature resistance, low temperature resistance, high strength, high toughness, etc. of power cable pipe, and meet the special requirements of trenchless construction and long-term use of 10kV high-voltage wires. However, the performance indicators of the pipe prepared by the combination, such as tensile strength, bending strength, elongation at break, Vicat softening temperature, etc., need to be improved.

[0007] CN105440455B discloses a polypropylene material, which is prepared from a polypropylene composition containing a polypropylene resin, an organic stiffening nucleating agent, an inorganic nucleating agent and an antioxidant. The drainage pipe made of the material has a high tensile elastic modulus, high notched impact strength, high ring stiffness, high resistance to impact loads and good heat resistance. However, the addition of the inorganic nucleating agent will affect the elongation at break of the pipe, and the elongation at break of the pipe prepared by the material cannot meet the requirements of the industry standard DL / T802.7-2010 for trenchless modified polypropylene plastic power cable conduits. Summary of the invention

[0008] The purpose of the present invention is to overcome the fact that the polypropylene pipe of the prior art cannot simultaneously meet the requirements of the performance of the power cable protection pipe in terms of tensile strength, rigidity-toughness balance and heat resistance, and to provide a polypropylene composition. The polypropylene composition has a simple composition, and the polypropylene material made from the composition has high rigidity, excellent toughness, excellent heat resistance and processing performance. The power cable protection pipe produced from the polypropylene composition or polypropylene material has significantly improved mechanical strength, which is better than the relevant requirements of the industry standard DL / T802.7-2010, and has good application prospects in the field of municipal power cable engineering.

[0009] In order to achieve the above object, the first aspect of the present invention provides a polypropylene composition, which contains a polypropylene base resin, an antioxidant, an α-crystal nucleating agent, an optional light stabilizer and a masterbatch;

[0010] The polypropylene base resin contains homopolymer polypropylene and ethylene-propylene random copolymer polypropylene with specific requirements.

[0011] The second aspect of the present invention provides a polypropylene material, which is prepared by blending, extruding and granulating the above-mentioned polypropylene composition.

[0012] The third aspect of the present invention provides a method for preparing a polypropylene material, which comprises blending, extruding and granulating the above-mentioned polypropylene composition.

[0013] A fourth aspect of the present invention provides a power cable protection pipe made of the above-mentioned polypropylene composition or polypropylene material.

[0014] Through the above technical scheme, the polypropylene composition of the present invention uses homopolymerized polypropylene and ethylene-propylene random copolymerized polypropylene as the polypropylene base resin, and adds an efficient α-crystal nucleating agent, an antioxidant, a light stabilizer and a masterbatch, so that the physical properties of the prepared polypropylene material are further improved, and it has high tensile strength, high rigidity, excellent toughness, excellent heat resistance and processing performance. The power cable protection pipe produced by using the polypropylene composition or polypropylene material has the characteristics of high tensile strength, high bending strength, high external pressure resistance, high toughness and high heat resistance, that is, its mechanical strength is significantly improved compared with the plastic pipes in the prior art, and is better than the relevant requirements of the industry standard DL / T802.7-2010, especially the external pressure resistance and elongation at break of the pipe. The cable protection pipe prepared by the polypropylene composition or polypropylene material has a tensile strength of ≥31.0MPa, an elongation at break of ≥480%, a bending strength of ≥35.7MPa, and other properties are also better than the relevant requirements of the industry standard DL / T802.7-2010, which is more beneficial to ensuring the long-term performance and service life of the pipe, and has very good application prospects as a power cable protection pipe. Therefore, the polypropylene composition, polypropylene material and polypropylene pipe provided by the present invention can be applied to a power cable protection pipe system, and have broad application prospects in the field of municipal power cable engineering. DETAILED DESCRIPTION

[0015] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0016] The first aspect of the present invention provides a polypropylene composition, which contains a polypropylene base resin, an antioxidant, an α-crystal nucleating agent, an optional light stabilizer and a masterbatch;

[0017] The polypropylene base resin contains homopolypropylene and ethylene-propylene random copolymer polypropylene.

[0018] The inventors have found that the α-crystal nucleating agent determined by the present invention has a significant improvement effect on the tensile strength, bending stress, bending modulus, simply supported beam notched impact strength and Vicat softening temperature of the polypropylene material containing the above-mentioned homopolypropylene and ethylene-propylene random copolymer polypropylene when added in a specific amount, while ensuring that the material maintains a high tensile strain at break.

[0019] In some embodiments of the present invention, the amount of the α-crystal nucleating agent is 0.01-0.1 parts by weight relative to 100 parts by weight of the polypropylene base resin. When the amount of the α-crystal nucleating agent is higher than 0.1 parts by weight, the tensile strain at break of the obtained polypropylene material will be significantly reduced. When the amount of the α-crystal nucleating agent is lower than 0.01 parts by weight, there is no significant effect on the improvement of the tensile strength, simply supported beam notched impact strength and other properties of the obtained polypropylene material. Preferably, the amount of the α-crystal nucleating agent is 0.015-0.06 parts by weight relative to 100 parts by weight of the polypropylene base resin, and most preferably 0.02-0.04 parts by weight. In some embodiments of the present invention, the amount of the antioxidant is 0.1-1.5 parts by weight, preferably 0.2-1 parts by weight, and most preferably 0.3-0.5 parts by weight relative to 100 parts by weight of the polypropylene base resin.

[0020] In some embodiments of the present invention, the amount of the masterbatch is 0-5 parts by weight, preferably 1-4 parts by weight, and most preferably 1.5-3 parts by weight, relative to 100 parts by weight of the polypropylene base resin.

[0021] In some embodiments of the present invention, the amount of the light stabilizer is 0-1 part by weight, preferably 0.1-0.8 part by weight, and most preferably 0.2-0.6 part by weight relative to 100 parts by weight of the polypropylene base resin. The inventors have found that adding a light stabilizer can better protect the pipeline from aging and degradation due to light during transportation and construction.

[0022] In some embodiments of the present invention, based on the total amount of the polypropylene base resin, the amount of homopolypropylene is 80-98 wt%, preferably 85-95 wt%; the amount of the ethylene-propylene random copolymer polypropylene is 2-20 wt%, preferably 5-15 wt%.

[0023] In the present invention, in the polypropylene base resin, the homopolypropylene has a moderate melt mass flow rate, which can have both good mechanical properties and processing flow properties, and the content of the comonomer of the ethylene-propylene random copolymer polypropylene is moderate, which is very beneficial to improving the rigidity and toughness balance of the composition. Therefore, in some embodiments of the present invention, at 230°C and 2.16kg load conditions, the melt mass flow rate of the homopolypropylene is 0.1-3g / 10min, preferably 0.2-2g / 10min, and more preferably 0.3-1g / 10min; the melt mass flow rate of the ethylene-propylene random copolymer polypropylene is 0.2-3g / 10min, preferably 0.2-0.6g / 10min.

[0024] In the present invention, the melt mass flow rate (ie, MFR) is tested according to GB / T3682.1-2018, and the test conditions include: temperature 230° C., load 2.16 kg.

[0025] In the present invention, based on the total molar number of the ethylene-propylene random copolymer polypropylene, the content of the ethylene structural unit in the ethylene-propylene random copolymer polypropylene is 30-70 mol%, preferably 40-60 mol%. The inventors have found that when the content of the ethylene structural unit of the ethylene-propylene random copolymer polypropylene is higher than 70 mol%, the rigidity of the polypropylene material prepared from the polypropylene composition decreases significantly, and the external pressure resistance of the prepared polypropylene pipe cannot meet the requirements; when the content is lower than 30 mol%, the toughness of the polypropylene material prepared from the polypropylene composition is insufficient, and the tensile strength of the prepared polypropylene pipe cannot meet the requirements.

[0026] In the present invention, the content of ethylene structural units in the ethylene-propylene random copolymer polypropylene is determined by nuclear magnetic resonance.

[0027] In an embodiment of the present invention, the antioxidant is at least one of a hindered phenol antioxidant, a phosphite antioxidant and a thioester antioxidant. Preferably, in order to further improve the heat aging resistance of the polypropylene material prepared from the above polypropylene composition and the long-term service life of the polypropylene pipe, the antioxidant is a hindered phenol antioxidant and a phosphite antioxidant and / or a thioester antioxidant. In some embodiments of the present invention, the weight ratio of the hindered phenol antioxidant: (phosphite antioxidant and / or thioester antioxidant) = 1: (0.1-8), preferably 1: (0.2-5), and most preferably 1: (0.3-3).

[0028] In some embodiments of the present invention, the hindered phenol antioxidant is selected from hindered phenol antioxidants with a melting point of 100-260° C. Preferably, the hindered phenol antioxidant is at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)-trione, and 2,2'-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate].

[0029] In some embodiments of the present invention, the phosphite antioxidant is selected from phosphite antioxidants having a melting point greater than 160° C. Preferably, the phosphite antioxidant is tris(2,4-di-tert-butylphenyl)phosphite and / or bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite.

[0030] In some embodiments of the present invention, the thioester antioxidant is dioctadecyl thiodipropionate and / or dilauryl thiodipropionate.

[0031] In some embodiments of the present invention, the α-crystal nucleating agent can be various α-crystal nucleating agents well known to those skilled in the art. Preferably, in order to further improve the performance of the obtained polypropylene material and the obtained polypropylene pipe, the α-crystal nucleating agent is at least one of an aryl phosphate nucleating agent, a sorbitol nucleating agent, and a carboxylic acid metal salt nucleating agent. Examples of the aryl phosphate nucleating agent may include, but are not limited to: methylene bis (2,4-di-tert-butylphenyl) phosphate hydroxyaluminum salt (commercially available, NA-21); specific examples of the sorbitol nucleating agent include, but are not limited to: di (3,4-dimethylbenzylidene) sorbitol (commercially available, referred to as 3988); specific examples of the carboxylic acid metal salt nucleating agent may include, but are not limited to: one or more of sodium succinate, aluminum benzoate, sodium benzoate, potassium benzoate, sodium cinnamate, sodium glutarate, calcium cyclohexane pimelate and butyl aluminum benzoate.

[0032] In the present invention, the nucleating agent can be directly added to the polypropylene base resin, or can be first made into concentrated masterbatch and then added to the polypropylene matrix.

[0033] In some embodiments of the present invention, in order to further improve the physical properties of the obtained polypropylene material and the obtained polypropylene pipe, the light stabilizer is a hindered amine light stabilizer. High molecular weight light stabilizers have good stability and have good synergistic effects with the above-mentioned antioxidant system, which can further improve the heat aging resistance, light aging performance and long-term use performance of the polypropylene material and its pipe obtained by the polypropylene composition. Therefore, in some preferred embodiments of the present invention, the hindered amine light stabilizer is at least one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, a polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, and poly-{[6-(1,1,3,3-tetramethylbutyl)-imino]-1,3,5 triazine-2,4-diyl}[2-(2,2,6,6-tetramethylpiperidinyl)-amino]-hexylene-[4-(2,2,6,6-tetramethylpiperidinyl)-imino].

[0034] In the present invention, the masterbatch may be a masterbatch well known to those skilled in the art, for example, a yellow or orange masterbatch whose base material is polypropylene. The masterbatch may be commercially available.

[0035] The second aspect of the present invention provides a polypropylene material, which is prepared by blending, extruding and granulating the above-mentioned polypropylene composition.

[0036] In some embodiments of the present invention, the tensile strength of the polypropylene material is ≥30.7 MPa, the tensile strain at break is ≥480%, the bending stress is ≥35.8 MPa, the bending modulus is ≥1590 MPa, and the notched impact strength of the simply supported beam is ≥30 kJ / m 2 , Vicat softening temperature ≥156℃.

[0037] In the present invention, the tensile strength of the polypropylene material is tested according to GB / T1040.2-2006; the tensile strain at break of the polypropylene material is tested according to GB / T1040.2-2006; the bending stress is tested according to GB / T9341-2008; the bending modulus is tested according to GB / T9341-2008; the simply supported beam notched impact strength is tested according to GB / T1043.1-2008; the Vicat softening temperature is tested according to GB / T1633-2000, wherein the test method is the A50 method.

[0038] The third aspect of the present invention provides a method for preparing a polypropylene material, which comprises blending, extruding and granulating the above-mentioned polypropylene composition.

[0039] In the present invention, the above method can be a one-step method or a two-step method. The one-step method is to directly mix the polypropylene base resin, α-crystal nucleating agent, antioxidant, light stabilizer and masterbatch in a high-speed mixer, and then extrude and granulate them at 160-250°C. The two-step method is: (1) extrude and granulate the α-crystal nucleating agent, antioxidant and light stabilizer to obtain the auxiliary agent masterbatch; (2) melt-blend and granulate the auxiliary agent masterbatch, polypropylene base resin and masterbatch; wherein the conditions for the extrusion granulation include: the temperature is 60-160°C, and the conditions for the melt-blending granulation include: the temperature is 160-250°C.

[0040] According to the method of the present invention, the amounts and types of the polypropylene base resin, α-crystal nucleating agent, antioxidant, light stabilizer and masterbatch are as described above and will not be repeated here.

[0041] In some embodiments of the present invention, in order to make the components mixed more uniformly, the method is a two-step method. Compared with the one-step method for preparing polypropylene materials, the two-step method for preparing polypropylene materials can significantly improve the dispersibility of α-crystal nucleating agent, antioxidant, and light stabilizer in the polypropylene base resin, thereby further improving the mechanical properties and long-term performance of the pipe made of the material.

[0042] In the present invention, the equipment used for granulation is a screw extruder granulator.

[0043] A fourth aspect of the present invention provides a power cable protection pipe made of the above-mentioned polypropylene composition or polypropylene material.

[0044] In the present invention, the density of the power cable protection pipe is ≥ 0.9 g / cm 3 , Vicat softening temperature ≥156℃, tensile strength ≥31MPa, elongation at break ≥480%, flexural strength ≥35.7MPa.

[0045] In the present invention, the density of the pipe is tested according to GB / T1033.1-2008; the Vicat softening temperature of the pipe is tested according to GB / T1633-2000, wherein the test method is A50 method; the tensile strength of the pipe is tested according to GB / T8804.3-2003; the elongation at break of the pipe is tested according to GB / T8804.3-2003; and the bending strength is tested according to GB / T9341-2008.

[0046] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, parts represent parts by weight.

[0047] The melt mass flow rate (i.e., MFR) of homopolypropylene and EPDM random copolymer polypropylene is tested in accordance with GB / T3682.1-2018. The test conditions include: temperature 230°C and load 2.16 kg.

[0048] The content of ethylene structural units in ethylene-propylene random copolymer polypropylene was determined by nuclear magnetic resonance.

[0049] The methods involved in the performance testing of polypropylene materials are as follows:

[0050] 1. MFR: Tested in accordance with GB / T3682.1-2018, the test conditions include: 230℃, 2.16kg;

[0051] 2. Tensile strength: tested in accordance with GB / T1040.2-2006;

[0052] 3. Tensile strain at break: Tested in accordance with GB / T1040.2-2006;

[0053] 4. Bending stress: tested in accordance with GB / T9341-2008;

[0054] 5. Flexural modulus: tested in accordance with GB / T9341-2008;

[0055] 6. Simply supported beam notch impact strength: tested in accordance with GB / T1043.1-2008;

[0056] 7. Vicat softening temperature: tested in accordance with GB / T1633-2000, where the test method is A50 method.

[0057] The methods involved in the performance testing of polypropylene pipes are as follows:

[0058] 1. Density: Tested in accordance with GB / T1033.1-2008;

[0059] 2. Ring stiffness: Tested according to GB / T9647-2015, the pipe specification is dn225×en20mm;

[0060] 3. Flattening test: Tested in accordance with GB / T9647-2015;

[0061] 4. Drop hammer impact test: Tested in accordance with GB / T14152-2001;

[0062] 5. Vicat softening temperature: tested in accordance with GB / T1633-2000, where the test method is A50 method;

[0063] 6. Tensile strength: Tested in accordance with GB / T8804.3-2003;

[0064] 7. Elongation at break: Tested in accordance with GB / T8804.3-2003;

[0065] 8. Bending strength: Tested in accordance with GB / T9341-2008.

[0066] Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available.

[0067] The homopolymer polypropylene and ethylene-propylene random copolymer polypropylene in the following examples and comparative examples were purchased from Yanshan Petrochemical Company, among which:

[0068] The grade of homopolymer polypropylene A1 is PPH-YSSH-1;

[0069] The grade of homopolymer polypropylene A2 is PPH-YSSH-2;

[0070] The grade of homopolymer polypropylene A3 is PPH-YSSH-3;

[0071] The grade of homopolymer polypropylene A4 is PPH-YSSH-4;

[0072] The grade of homopolymer polypropylene A5 is PPH-YSSH-5;

[0073] The grade of homopolymer polypropylene A6 is PPH-YSSH-6;

[0074] The grade of ethylene-propylene random copolymer polypropylene B1 is PPR-YSSH-1;

[0075] The grade of ethylene-propylene random copolymer polypropylene B2 is PPR-YSSH-2;

[0076] The grade of ethylene-propylene random copolymer polypropylene B3 is PPR-YSSH-3;

[0077] The grade of ethylene-propylene random copolymer polypropylene B4 is PPR-YSSH-4;

[0078] The grade of ethylene-propylene random copolymer polypropylene B5 is PPR-YSSH-5;

[0079] The grade of ethylene-propylene random copolymer polypropylene B6 is PPR-YSSH-6;

[0080] The grade of ethylene-propylene random copolymer polypropylene B7 is PPR-YSSH-7;

[0081] The grade of ethylene-propylene random copolymer polypropylene B8 is PPR-YSSH-8.

[0082] Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (hindered phenol antioxidant) was purchased from BASF, brand number 1010;

[0083] Tris(2,4-di-tert-butylphenyl)phosphite (phosphite antioxidant) was purchased from BASF, brand number 168;

[0084] Bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (light stabilizer) was purchased from BASF, brand number 770;

[0085] Methylene bis(2,4-di-tert-butylphenyl) phosphate hydroxyaluminum salt (aryl phosphate nucleating agent) was purchased from Asahi Kasei Corporation, Japan, with the brand name NA-21;

[0086] The masterbatch was purchased from Beijing Jihe Company, brand number 6428;

[0087] Di(3,4-dimethylbenzylidene)sorbitol (sorbitol nucleating agent) was purchased from Milliken & Company, brand number 3988;

[0088] 1,3,5-Trimethyl-2,4,6-tri(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (hindered phenol antioxidant) was purchased from BASF, brand number 1330;

[0089] Poly-{[6-(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl}[2-(2,2,6,6-tetramethylpiperidinyl)-amino]-hexylidene-[4-(2,2,6,6-tetramethylpiperidinyl)-imino] (light stabilizer) was purchased from BASF with the brand number 944;

[0090] Sodium benzoate nucleating agent (carboxylic acid metal salt nucleating agent) was purchased from Guangzhou Chenghe Company with the brand name NAR6;

[0091] 2,2'-Thiodiethyl bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (hindered phenol antioxidant) was purchased from BASF, brand number 1035;

[0092] Dioctadecyl thiodipropionate (thioester antioxidant) was purchased from BASF with the brand name DSTP;

[0093] The polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol (light stabilizer) was purchased from BASF, brand 622;

[0094] Bis(p-tert-butyl)benzoic acid hydroxyaluminum (carboxylic acid metal salt nucleating agent) was purchased from Guangzhou Chenghe Company with the brand name NAA325;

[0095] 1,3,5-Tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione (hindered phenol antioxidant) was purchased from BASF, brand number 1790;

[0096] Dilauryl thiodipropionate (thioester antioxidant) was purchased from BASF with the brand name DLTP.

[0097] Example 1

[0098] (1) Composition

[0099]

[0100]

[0101] (2) Preparation of polypropylene materials

[0102] First, an aromatic phosphate nucleating agent NA-21, an antioxidant and a light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A1, ethylene-propylene random copolymer polypropylene B1 and a masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P1.

[0103] Example 2

[0104] (1) Composition

[0105]

[0106] (2) Preparation of polypropylene materials

[0107] First, sorbitol nucleating agent 3988, antioxidant and light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A1, ethylene-propylene random copolymer polypropylene B2 and masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P2.

[0108] Example 3

[0109] (1) Composition

[0110]

[0111] (2) Preparation of polypropylene materials

[0112] First, sodium benzoate nucleating agent NAR6, antioxidant and light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A1, ethylene-propylene random copolymer polypropylene B3 and masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P3.

[0113] Example 4

[0114] (1) Composition

[0115]

[0116]

[0117] (2) Preparation of polypropylene materials

[0118] First, an aromatic phosphate nucleating agent NA-21, an antioxidant and a light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A2, ethylene-propylene random copolymer polypropylene B4 and a masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P4.

[0119] Example 5

[0120] (1) Composition

[0121]

[0122] (2) Preparation of polypropylene materials

[0123] First, bis(p-tert-butylbenzoic acid) hydroxyaluminum NAA325, an antioxidant, and a light stabilizer are mixed uniformly in proportion and then fed into a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160°C to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A3, ethylene-propylene random copolymer polypropylene B5, and a masterbatch are mixed uniformly in proportion, and the obtained mixture is fed into a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is controlled at 180°C, 190°C, 220°C, 230°C, 230°C, and 200°C, respectively, and the vacuum degree of each section is maintained at 0.02-0.09MPa; the mixture is melted, sheared, dispersed, compressed, exhausted, and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die to obtain a polypropylene material P5.

[0124] Example 6

[0125] (1) Composition

[0126]

[0127] (2) Preparation of polypropylene materials

[0128] First, an aromatic phosphate nucleating agent NA-21, an antioxidant and a light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A1, ethylene-propylene random copolymer polypropylene B6 and a masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P6.

[0129] Example 7

[0130] (1) Composition

[0131]

[0132] (2) Preparation of polypropylene materials

[0133] First, an aromatic phosphate nucleating agent NA-21, an antioxidant and a light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A4, ethylene-propylene random copolymer polypropylene B7 and a masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P7.

[0134] Example 8

[0135] (1) Composition

[0136]

[0137] (2) Preparation of polypropylene materials

[0138] First, an aromatic phosphate nucleating agent NA-21, an antioxidant and a light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A1, ethylene-propylene random copolymer polypropylene B1 and a masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P8.

[0139] Example 9

[0140] (1) Composition

[0141]

[0142] (2) Preparation of polypropylene materials

[0143] First, an aromatic phosphate nucleating agent NA-21, an antioxidant and a light stabilizer are mixed uniformly in proportion and then sent to a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A1, ethylene-propylene random copolymer polypropylene B1 and a masterbatch are mixed uniformly in proportion, and the obtained mixture is sent to a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P9.

[0144] Example 10

[0145] A polypropylene composition, a polypropylene material P10 and a polypropylene pipe were prepared according to the method of Example 1, except that homopolypropylene A5 was used instead of homopolypropylene A1, and the MFR of the homopolypropylene was 0.80 g / 10 min.

[0146] Comparative Example 1

[0147] (1) Composition

[0148]

[0149] (2) Preparation of polypropylene materials

[0150] First, an antioxidant and a light stabilizer are mixed uniformly in proportion and then fed into a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A6, ethylene-propylene random copolymer polypropylene B8 and a masterbatch are mixed uniformly in proportion, and the obtained mixture is fed into a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a reference polypropylene material DP1.

[0151] Comparative Example 2

[0152] (1) Composition

[0153]

[0154] (2) Preparation of polypropylene materials

[0155] First, an aromatic phosphate nucleating agent NA-21, an antioxidant and a light stabilizer are mixed uniformly in proportion and then fed into a twin-screw extruder, the screw speed is adjusted to 190-220 rpm, and the temperature of each section is controlled at 60-160° C. to obtain an additive masterbatch; then the additive masterbatch, homopolypropylene A4 and a color masterbatch are mixed uniformly in proportion, and the obtained mixture is fed into a twin-screw extruder, the screw speed is adjusted to 200-240 rpm, the temperature of each section is respectively controlled at 180° C., 190° C., 220° C., 230° C., 230° C. and 200° C., and the vacuum degree of each section is maintained at 0.02-0.09 MPa; the mixture is melted, sheared, dispersed, compressed, exhausted and plasticized in the screw and barrel of the extruder, and then extruded and pelletized through a die head to obtain a polypropylene material P1.

[0156] Test Example 1

[0157] The performance tests were performed on the polypropylene materials prepared in Examples 1-10 and Comparative Examples 1-2. The results are shown in Table 1.

[0158] Table 1

[0159]

[0160]

[0161] Note 1: MFR test conditions are 230℃, load 2.16kg;

[0162] Note 2: The simply supported beam notched impact strength is the 0°C impact performance of the notched spline. P means that the spline is partially broken, and C means that the spline is completely broken.

[0163] Note 3: Vicat softening temperature is A50 method.

[0164] Test Example 2

[0165] The polypropylene materials prepared in Examples 1-10 and Comparative Examples 1-2 were used to prepare pipes, and the pipe specifications were dn225×en20mm. The prepared polypropylene pipes were tested for performance, and the results are shown in Table 2.

[0166] Table 2

[0167]

[0168]

[0169] Note 1: The conditions for the ring stiffness test are: pipe specification is dn225×en20mm, compression rate is 10±0.5mm / min, and test temperature is room temperature (23℃);

[0170] Note 2: Vicat softening temperature is A50 method.

[0171] It can be seen from Table 1 that the polypropylene material prepared using the polypropylene composition of the present invention has excellent physical properties, and has high tensile strength, bending stress, bending modulus, simply supported beam notched impact strength and Vicat softening temperature while maintaining a high tensile strain at break, that is, it has high rigidity, excellent toughness, excellent heat resistance and processing performance.

[0172] It can be seen from Table 2 that the pipe made of the polypropylene material of the present invention has good tensile strength, external pressure resistance, high toughness and high heat resistance, that is, good mechanical strength. At the same time, the tensile strength of the pipe made of the polypropylene material of the present invention is ≥31.0MPa, the elongation at break is ≥480%, the bending strength is ≥35.7MPa, and other properties are also better than the relevant requirements of the industry standard DL / T802.7-2010, which is more beneficial to ensuring the long-term performance and service life of the pipe, and has a very good application prospect as a power cable protection pipe.

[0173] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A polypropylene composition, characterized in that The polypropylene composition contains a polypropylene base resin, an antioxidant, an alpha crystal nucleating agent, an optional light stabilizer and a masterbatch; The polypropylene base resin contains homopolymer polypropylene and ethylene-propylene random copolymer polypropylene; Based on the total amount of the polypropylene base resin, the amount of the ethylene-propylene random copolymer polypropylene is 5-15% by weight, and the amount of the homopolymer polypropylene is 85-95% by weight; In the ethylene-propylene random copolymer polypropylene, the content of ethylene structural units is 40-60 mol%; Relative to 100 parts by weight of the polypropylene base resin, the amount of the α-crystal nucleating agent is 0.02-0.04 parts by weight, and the amount of the antioxidant is 0.3-0.5 parts by weight.

2. The polypropylene composition according to claim 1, wherein The amount of the masterbatch is 0-5 parts by weight relative to 100 parts by weight of the polypropylene base resin; The amount of the light stabilizer is 0-1 part by weight relative to 100 parts by weight of the polypropylene base resin.

3. The polypropylene composition according to claim 2, wherein The amount of the masterbatch is 1-4 parts by weight relative to 100 parts by weight of the polypropylene base resin; The amount of the light stabilizer is 0.1-0.8 parts by weight relative to 100 parts by weight of the polypropylene base resin.

4. The polypropylene composition according to claim 3, wherein The amount of the masterbatch is 1.5-3 parts by weight relative to 100 parts by weight of the polypropylene base resin; The amount of the light stabilizer is 0.2-0.6 parts by weight relative to 100 parts by weight of the polypropylene base resin.

5. The polypropylene composition according to any one of claims 1 to 4, wherein The melt mass flow rate of the homopolymer polypropylene at 230° C. and 2.16 kg load is 0.1-3 g / 10 min; And / or, the ethylene-propylene random copolymer polypropylene has a melt mass flow rate of 0.2-3 g / 10 min at 230° C. and 2.16 kg load.

6. The polypropylene composition according to claim 5, wherein The melt mass flow rate of the homopolymer polypropylene at 230° C. and 2.16 kg load is 0.2-2 g / 10 min; And / or, the ethylene-propylene random copolymer polypropylene has a melt mass flow rate of 0.2-0.6 g / 10 min at 230° C. and 2.16 kg load.

7. The polypropylene composition according to claim 6, wherein The homopolypropylene has a melt mass flow rate of 0.3-1 g / 10 min at 230° C. and a load of 2.16 kg.

8. The polypropylene composition according to any one of claims 1 to 4, wherein The antioxidant is at least one of a hindered phenol antioxidant, a phosphite antioxidant and a thioester antioxidant.

9. The polypropylene composition according to claim 8, wherein m 受阻酚类抗氧剂 :m 亚磷酸酯抗氧剂和 / 或硫酯类抗氧剂 =1:0.1-8。 10. The polypropylene composition according to claim 9, wherein m 受阻酚类抗氧剂 :m 亚磷酸酯抗氧剂和 / 或硫酯类抗氧剂 =1:0.2-5。 11. The polypropylene composition according to claim 10, wherein m 受阻酚类抗氧剂 :m 亚磷酸酯抗氧剂和 / 或硫酯类抗氧剂 =1:0.3-3。 12. The polypropylene composition according to claim 8, wherein the hindered phenol antioxidant is selected from hindered phenol antioxidants having a melting point of 100-260°C; And / or, the phosphite antioxidant is selected from phosphite antioxidants having a melting point greater than 160°C.

13. The polypropylene composition according to claim 12, wherein the hindered phenol antioxidant is at least one selected from pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-(3,5-di-tert-butyl-4-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)-trione, and 2,2'-thiodiethylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; And / or, the phosphite antioxidant is selected from tris(2,4-di-tert-butylphenyl)phosphite and / or bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite; And / or, the thioester antioxidant is dioctadecyl thiodipropionate and / or dilauryl thiodipropionate.

14. The polypropylene composition according to any one of claims 1 to 4, wherein The α-crystal nucleating agent is at least one of an aromatic phosphate nucleating agent, a sorbitol nucleating agent, and a carboxylic acid metal salt nucleating agent; The light stabilizer is a hindered amine light stabilizer.

15. The polypropylene composition according to claim 14, wherein The light stabilizer is at least one of bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate, a polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, and poly-{[6-(1,1,3,3-tetramethylbutyl)-imino]-1,3,5-triazine-2,4-diyl}[2-(2,2,6,6-tetramethylpiperidinyl)-amino]-hexamethylene-[4-(2,2,6,6-tetramethylpiperidinyl)-imino].

16. A polypropylene material, which is prepared by blending, extruding and granulating the polypropylene composition according to any one of claims 1 to 15.

17. The polypropylene material according to claim 16, wherein The tensile strength of the polypropylene material is ≥30.7MPa, the tensile strain at break is ≥480%, the bending stress is ≥35.8MPa, the bending modulus is ≥1590MPa, and the simply supported beam notched impact strength is ≥30kJ / m 2 , Vicat softening temperature ≥156℃.

18. A method for preparing a polypropylene material, characterized in that: The method comprises blending, extruding and pelletizing the polypropylene composition described in any one of claims 1 to 15.

19. The method according to claim 18, wherein: The method comprises: (1) extruding and granulating an α-crystal nucleating agent, an antioxidant and a light stabilizer to prepare an additive masterbatch; (2) melt-blending and granulating the additive masterbatch, the polypropylene base resin and the color masterbatch; The conditions for the extrusion granulation include: a temperature of 60-160°C, and the conditions for the melt blending granulation include: a temperature of 160-250°C.

20. A protective pipe for power cables made from the polypropylene composition according to any one of claims 1 to 15 or the polypropylene material according to claim 16 or 17.

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