Anhydride-containing polypropylene grafts and method for preparing polypropylene grafts

Abstract

The present invention relates to an anhydride group-containing polypropylene graft for insulating materials, which belongs to the polymer field, and to a method for preparing the same. The anhydride group-containing polypropylene graft contains structural units derived from a polypropylene copolymer, structural units derived from anhydride monomers, and structural units derived from an alkenyl-containing polymerizable monomer, and the content of the grafted structural units derived from the anhydride monomers and the alkenyl-containing polymerizable monomers in the anhydride group-containing polypropylene graft is 0.1-5 wt % relative to the weight of the anhydride group-containing polypropylene graft. The molar ratio of the structural units derived from the anhydride monomers to the structural units derived from the alkenyl-containing polymerizable monomers in the anhydride group-containing polypropylene graft is 1:1-20. The polypropylene copolymer has at least one of the following characteristics: a comonomer content of 0.5-40 mol %, a xylene soluble content of 2-80 wt %, a comonomer content in the xylene solubles of 10-70 wt %, and an intrinsic viscosity ratio of the comonomer content in the xylene solubles to the polypropylene copolymer of 0.3-5. The anhydride group-containing polypropylene grafts of the present invention can allow for both mechanical and electrical properties at higher use temperatures.

Description

Detailed Description of the Invention

[0001] [Technical field] The present invention belongs to the polymer field, and in particular relates to an anhydride group-containing polypropylene graft, a method for preparing an anhydride group-containing polypropylene graft, an anhydride group-containing polypropylene graft obtained by said method, and the use of said anhydride group-containing polypropylene graft and cable.

[0002] [Background technology] Due to their excellent electrical insulating properties and low manufacturing costs, polymeric materials are widely used as insulating materials for electrical equipment in electrical engineering and the power industry. Among these, polymeric plastic insulating materials with simple structures, such as polyethylene, are particularly versatile. Cross-linked polyethylene, copolymer polyolefins, and rubber materials developed based on polyethylene are widely used in the insulation of motors and transformers, circuit insulation, and circuit breakers. Ethylene-based polymer insulating materials have better mechanical and thermal properties, excellent electrical insulating properties, and low prices, making them a relatively mature insulating material developed in engineering.

[0003] With the rapid development of the electric power industry, power grid systems are approaching higher voltage levels and greater electrical energy transmission capacity, placing greater demands on the performance of insulating materials. In response to this trend, conventional polyethylene-based insulating materials cannot meet the higher long-term service temperature and electric field requirements (the maximum long-term service temperature of currently available cross-linked polyethylene insulating materials is 70°C). Therefore, there is an urgent need to develop new insulating materials for electrical equipment that can meet the high service temperature and electric field strength requirements.

[0004] As a polymer plastic with a simple structure, polypropylene material possesses all the advantages of polyethylene. Compared to polyethylene, polypropylene has better electrical insulation properties and a higher melting point, making it suitable for use in harsher environments. However, polypropylene's mechanical properties are somewhat inferior to those of polyethylene, and it is particularly brittle at low temperatures, preventing its direct use as an insulating material. Therefore, to maintain its insulating properties under high temperatures and high electric fields, polypropylene must be modified to achieve comprehensive control of its electrical, mechanical, and thermal properties.

[0005] Many literatures and data have shown that doping nanoparticles into polypropylene materials for modification is an effective method for improving their electrical insulation performance. However, in actual manufacturing, the difficulty of controlling the doping behavior of nanoparticles leads to the aggregation of nanoparticles, which in turn reduces the insulating performance of the material, limiting its widespread application in practical engineering.

[0006] Therefore, it is necessary to explore new modified polypropylene materials that have clear insulating performance control ability, can take into account both mechanical and thermal properties, have stable performance, are easy to prepare, and are suitable for practical application in engineering.

[0007] [Contents of the invention] The present invention aims to overcome the drawbacks of the prior art and provides a novel anhydride group-containing polypropylene graft that can take into consideration both mechanical and electrical properties at higher use temperatures and is suitable for use under high temperature and high operating field strength conditions.

[0008] A first aspect of the present invention is an anhydride group-containing polypropylene graft for use in an insulating material, which comprises structural units derived from a polypropylene copolymer, structural units derived from an anhydride monomer, and structural units derived from an alkenyl-containing polymerizable monomer, and the content of the structural units derived from the anhydride monomer and the structural units derived from the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft in a grafted state is 0.1 to 5 wt %, preferably 0.4 to 3 wt %, based on the weight of the anhydride group-containing polypropylene graft, and the molar ratio of the structural units derived from the anhydride monomer to the structural units derived from the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 1:1 to 20, preferably 1:1 to 10, and the poly The present invention provides an anhydride group-containing polypropylene graft, wherein the propylene copolymer has at least one of the following characteristics: a comonomer content of 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; a xylene soluble content of 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; a comonomer content in the xylene solubles of 10 to 70 wt%, preferably 10 to 50 wt%, and more preferably 20 to 35 wt%; and an intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer of 0.3 to 5, preferably 0.5 to 3, and even more preferably 0.8 to 1.3.

[0009] A second aspect of the present invention is to provide a method for preparing an anhydride group-containing polypropylene graft for use in an insulating material, the method comprising the step of grafting a reaction mixture containing a polypropylene copolymer, an anhydride monomer, and an alkenyl-containing polymerizable monomer in the presence of an inert gas to obtain an anhydride group-containing polypropylene graft, wherein the graft reaction is carried out under the following conditions: the content of structural units in the anhydride group-containing polypropylene graft, which are derived from the anhydride monomer and the alkenyl-containing polymerizable monomer and are in a grafted state, is 0.1 to 5 wt %, preferably 0.4 to 3 wt %, based on the weight of the anhydride group-containing polypropylene graft; and The molar ratio of structural units derived from aqueous monomers is 1:1 to 20, preferably 1:1 to 10, and the polypropylene copolymer has at least one of the following characteristics: the comonomer content is 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; the xylene solubles content is 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; the comonomer content in the xylene solubles is 10 to 70 wt%, preferably 10 to 50 wt%, and more preferably 20 to 35 wt%; and the intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer is 0.3 to 5, preferably 0.5 to 3, and more preferably 0.8 to 1.3.

[0010] A third aspect of the present invention is to provide an anhydride group-containing polypropylene graft for insulating materials obtained by the above preparation method.

[0011] A fourth aspect of the present invention provides the use of the anhydride group-containing polypropylene graft as an insulating material.

[0012] A fifth aspect of the present invention provides a cable comprising at least one conductor and at least one electrical insulating layer surrounding the conductor, the material of the electrical insulating layer being the anhydride group-containing polypropylene graft described above.

[0013] A sixth aspect of the present invention provides an insulating material, characterized in that it is an insulating material containing the anhydride group-containing polypropylene graft.

[0014] [Brief description of the drawing] FIG. 1 is a schematic cross-sectional view of a cable according to one embodiment of the present invention.

[0015] (Explanation of symbols) 1 - conductor, 2 - conductor shielding layer, 3 - electrical insulation layer, 4 - electrical insulation shielding layer, 5 - metal shielding layer, 6 - inner sheath layer, 7 - exterior sheath, 8 - outer sheath layer.

[0016] [Detailed Description of the Invention] A first aspect of the present invention is to provide an anhydride group-containing polypropylene graft for use in an insulating material, characterized in that the anhydride group-containing polypropylene graft contains structural units derived from a polypropylene copolymer, structural units derived from an anhydride monomer, and structural units derived from an alkenyl-containing polymerizable monomer, the content of the structural units in the anhydride group-containing polypropylene graft that are in a grafted state and are derived from the anhydride monomer and the alkenyl-containing polymerizable monomer is 0.1 to 5 wt %, preferably 0.4 to 3 wt %, based on the weight of the anhydride group-containing polypropylene graft, and the molar ratio of the structural units derived from the anhydride monomer to the structural units derived from the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 1:1 to 20, preferably 1:1 to 10.

[0017] The polypropylene copolymer has at least one of the following characteristics: a comonomer content of 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; a xylene soluble content of 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; a comonomer content in the xylene solubles of 10 to 70 wt%, preferably 10 to 50 wt%, and more preferably 20 to 35 wt%; and an intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer of 0.3 to 5, preferably 0.5 to 3, and even more preferably 0.8 to 1.3.

[0018] Preferably, the content of structural units in the anhydride group-containing polypropylene graft, which are derived from an anhydride monomer and are in a grafted state, is 0.05 to 2% by weight, and more preferably 0.2 to 0.7% by weight.

[0019] Preferably, the anhydride is selected from anhydrides having at least one olefinic unsaturation. Preferably, the anhydride is selected from maleic anhydride and itaconic anhydride. More preferably, the acid anhydride is maleic anhydride.

[0020] Preferably, the present invention provides an anhydride group-containing polypropylene graft for use in an insulating material, characterized in that the anhydride group-containing polypropylene graft contains structural units derived from a polypropylene copolymer, structural units derived from an anhydride monomer, and structural units derived from an alkenyl-containing polymerizable monomer, the content of structural units in the anhydride group-containing polypropylene monomer that are in a grafted state and are derived from the anhydride monomer and the alkenyl-containing polymerizable monomer is 0.1 to 5 wt %, preferably 0.4 to 3 wt %, relative to the weight of the anhydride group-containing polypropylene graft, and the molar ratio of the structural units derived from the anhydride monomer to the structural units derived from the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 1:1 to 20, preferably 1:1 to 10. The polypropylene copolymer has at least one of the following characteristics: a comonomer content of 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; a xylene soluble content of 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; a comonomer content in the xylene solubles of 10 to 70 wt%, preferably 10 to 50 wt%, and more preferably 20 to 35 wt%; and an intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer of 0.3 to 5, preferably 0.5 to 3, and even more preferably 0.8 to 1.3.

[0021] Preferably, the content of structural units in the anhydride group-containing polypropylene graft, which are derived from an anhydride monomer and are in a grafted state, is 0.05 to 2% by weight, and more preferably 0.2 to 0.7% by weight.

[0022] In the present invention, the term "structural unit" refers to a part of an anhydride group-containing polypropylene graft, and its form is not limited. Specifically, the term "structural unit derived from a polypropylene copolymer" refers to a product formed from a polypropylene copolymer, including not only "radical" but also "polymer" forms. The term "structural unit derived from a (maleic) anhydride monomer" refers to a product formed from a (maleic) anhydride monomer, including not only "radical" but also "monomer" and "polymer" forms. The term "structural unit derived from an alkenyl-containing polymerizable monomer" refers to a product formed from an alkenyl-containing polymerizable monomer, including not only "radical" but also "monomer" and "polymer" forms. The "structural unit" may be a repeating unit or a non-repeating independent unit.

[0023] In the present invention, the structural units derived from (maleic) anhydride monomers in a "grafted" state refer to structural units derived from (maleic) anhydride monomers that form a covalent bond (graft) with a polypropylene copolymer. The structural units derived from alkenyl-containing polymerizable monomers in a "grafted" state refer to structural units derived from alkenyl-containing polymerizable monomers that form a covalent bond (graft) with a polypropylene copolymer.

[0024] In the present invention, the term "comonomer" of the polypropylene copolymer is known to those skilled in the art and means a monomer copolymerized with propylene.

[0025] According to the present invention, the anhydride group-containing polypropylene graft is preferably prepared by a grafting reaction, preferably a solid-phase grafting reaction, of a polypropylene copolymer, a (maleic) anhydride monomer, and an alkenyl-containing polymerizable monomer. Since the grafting reaction of the present invention is a radical polymerization reaction, the term "in a grafted state" refers to a state in which a bond is formed with another reactant after radical polymerization. The bond includes both a direct bond and an indirect bond.

[0026] During the grafting reaction, the anhydride monomer and the alkenyl-containing polymerizable monomer can polymerize with themselves or with each other to form a certain amount of non-grafted polymer. In the present invention, the term "anhydride group-containing polypropylene graft" includes not only the product (crude product) directly obtained by the grafting reaction of a polypropylene copolymer, a (maleic) anhydride monomer, and an alkenyl-containing polymerizable monomer, but also the pure graft-modified polypropylene product obtained by further purifying the product.

[0027] According to the present invention, the polypropylene copolymer (the base polypropylene in the present invention) is a propylene copolymer containing ethylene or a higher α-olefin or a mixture thereof. Specifically, the comonomer of the polypropylene copolymer is at least one selected from C2-C8 α-olefins other than propylene. The C2-C8 α-olefins other than propylene include, but are not limited to, at least one selected from ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene, preferably ethylene and / or 1-butene, and more preferably, the polypropylene copolymer consists of propylene and ethylene.

[0028] The polypropylene copolymer of the present invention may be a heterophasic propylene copolymer. The heterophasic propylene copolymer may contain a propylene homopolymer or a propylene random copolymer matrix component (1) and another propylene copolymer component (2) dispersed therein. In a propylene random copolymer, the comonomer is randomly distributed in the propylene polymer backbone. Preferably, the polypropylene copolymer of the present invention is a heterophasic propylene copolymer prepared in situ in a reactor by conventional processing.

[0029] According to a preferred embodiment, the heterophasic propylene copolymer comprises a propylene homopolymer or random copolymer matrix (1) and a propylene copolymer component (2) comprising one or more ethylene or higher α-olefin comonomers dispersed therein. The heterophasic propylene copolymer may have an islands-in-the-sea or co-continuous structure.

[0030] Two heterophasic propylene copolymers are known in the art: those containing a random copolymer of propylene as the matrix phase, and those containing a homopolymer of propylene as the matrix phase. The random copolymer matrix (1) is a copolymer in which the comonomer moieties are randomly distributed on the polymer chain, in other words, it consists of two monomer units of random length (including single molecules) in alternating order. Preferably, the comonomer in matrix (1) is selected from ethylene or butene. It is particularly preferred that the comonomer in matrix (1) is ethylene.

[0031] Preferably, the propylene copolymer (2) dispersed in the heterophasic propylene copolymer homo- or copolymer matrix (1) is substantially amorphous. The term "substantially amorphous" means herein that the propylene copolymer (2) has a lower crystallinity than the homo- or copolymer matrix (1).

[0032] According to the present invention, the polypropylene copolymer has at least one of the following characteristics in addition to the above compositional characteristics: a comonomer content of 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; a xylene soluble content of 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; a comonomer content in the xylene solubles of 10 to 70 wt%, preferably 10 to 50 wt%, and more preferably 20 to 35 wt%; and an intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer of 0.3 to 5, preferably 0.5 to 3, and more preferably 0.8 to 1.3.

[0033] According to the present invention, the polypropylene copolymer preferably further has at least one of the following characteristics: the melt flow rate under a load of 2.16 kg at 230°C is 0.01 to 60 g / 10 min, preferably 0.05 to 35 g / 10 min, more preferably 0.5 to 15 g / 10 min. The melting point Tm is 100°C or higher, preferably 110 to 180°C, more preferably 110 to 170°C, even more preferably 120 to 170°C, and still more preferably 120 to 166°C. The weight average molecular weight is preferably 20 x 10 4 ~60×10 4 g / mol. A base polypropylene with a high Tm has sufficient impact strength and flexibility at both low and high temperatures, and in addition, when a base polypropylene with a high Tm is used, the graft-modified polypropylene of the present invention has the advantage of being able to withstand higher use temperatures. The polypropylene copolymer of the present invention is preferably in the form of a porous granular or powdered resin.

[0034] According to the present invention, the polypropylene copolymer preferably further has at least one of the following characteristics: a flexural modulus of 10 to 1000 MPa, preferably 50 to 600 MPa; an elongation at break of 200% or more, preferably 300% or more. Preferably, the tensile strength of the polypropylene copolymer is greater than 5 MPa, preferably 10 to 40 MPa.

[0035] The polypropylene copolymer of the present invention can include, but is not limited to, any commercially available polypropylene powder suitable for the present invention, such as NS06 from Sinopec Wuhan Petrochemical and SPF179 from Sinopec Qilu Petrochemical. It can also be produced by polymerization processes described in Chinese patents CN1081683, CN1108315, CN1228096, CN1281380, CN1132865C, and CN102020733A. Common polymerization processes include the Spheripol process from Basell, the Hypol process from Mitsui Oil Chemical, the Borstar PP process from Borealis, the Unipol process from DOW Chemical, and the Innovene gas-phase process from INEOS (formerly BP-Amoco).

[0036] According to the present invention, the anhydride group-containing polypropylene graft preferably has at least one of the following characteristics: a melt flow rate under a load of 2.16 kg at 230°C of 0.01 to 30 g / 10 min, preferably 0.05 to 20 g / 10 min, more preferably 0.1 to 10 g / 10 min, and even more preferably 0.2 to 8 g / 10 min; a flexural modulus of 10 to 1050 MPa, preferably 20 to 1000 MPa, and more preferably 50 to 500 MPa; and an elongation at break of 200% or more, preferably 300% or more. Preferably, the tensile strength of the anhydride group-containing polypropylene graft is greater than 5 MPa, preferably 10 to 40 MPa.

[0037] According to the invention, preferably the anhydride group-containing polypropylene graft has at least one of the following characteristics: - the use temperature of the anhydride group-containing polypropylene graft is 90°C or higher, preferably 90 to 160°C; - Breakdown field strength E of polypropylene graft containing anhydride groups at 90°C gis 210 kV / mm or more, preferably 210 to 800 kV / mm; - Breakdown field strength E of polypropylene graft containing anhydride groups at 90°C g and the breakdown field strength E of the polypropylene copolymer at 90°C, divided by the breakdown field strength E of the polypropylene copolymer at 90°C, the rate of change in breakdown field strength ΔE / E exceeds 1.8%, preferably 2 to 50%, more preferably 5 to 35%, and even more preferably 8 to 28%; - DC volume resistivity ρ of polypropylene grafted with anhydride groups at 90°C and a field strength of 15 kV / mm vg But 1.5 x 10 13 Ω.m or more, preferably 1.5×10 13 Ω.m~1.0×10 20 is Ω.m; - DC volume resistivity ρ of polypropylene copolymer at 90°C and an electric field strength of 15 kV / mm v DC volume resistivity ρ of polypropylene graft containing anhydride groups at 90°C and an electric field strength of 15 kV / mm vg The ratio (ρ vg / ρ v ) exceeds 2, and is preferably 2.1 to 40, more preferably 2.3 to 20, and even more preferably 2.5 to 10.

[0038] Preferably, the dielectric constant of the anhydride group-containing polypropylene graft at 90° C. and 50 Hz exceeds 2.0, preferably 2.1 to 2.5.

[0039] According to the present invention, the alkenyl-containing polymerizable monomer is preferably at least one selected from monomers having a structure represented by Formula 1:

[0040] [ka]

[0041] In formula 1, R b , R c , R dare each independently selected from H, substituted or unsubstituted alkyl; R a is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted ester group, substituted or unsubstituted carboxyl, substituted or unsubstituted cycloalkyl or heterocyclyl, cyano.

[0042] Preferably, R b , R c , R d are each independently selected from H, substituted or unsubstituted C1-C6 alkyl; preferably, R b , R c , R d are each independently selected from H, substituted or unsubstituted C1-C3 alkyl; R a is a substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C1-C 20 Alkoxy, substituted or unsubstituted C6-C 20 Aryl, substituted or unsubstituted C1-C 20 Ester groups, substituted or unsubstituted C1-C 20 Carboxyl, substituted or unsubstituted C3-C 20 cycloalkyl or heterocyclyl, cyano; the substituents of which are halogen, hydroxy, amino, C1-C6 alkyl, C3-C6 cycloalkyl; preferably, R a is a substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C1-C 18 Alkoxy, substituted or unsubstituted C6-C 12 Aryl, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 Carboxyl, substituted or unsubstituted C3-C 12 cycloalkyl or heterocyclyl, cyano, the substituents of which are halogen, C1-C6 alkyl, C3-C6 cycloalkyl; more preferably, R a is a substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C 12It is selected from alkoxy, substituted or unsubstituted C6-C8 aryl, substituted or unsubstituted C1-C6 ester group, substituted or unsubstituted C1-C6 carboxyl, substituted or unsubstituted C3-C6 cycloalkyl or heterocyclyl, cyano, preferably heterocyclyl is selected from imidazolyl, pyrazolyl, carbazolyl, pyrrolidinonyl, pyridyl, piperidinyl, caprolactam group, pyrazinyl, thiazolyl, purinyl, morpholinyl, oxazolinyl.

[0043] More preferably, R b , R c , R d are each independently selected from H, substituted or unsubstituted C1-C6 alkyl; R a is selected from a group represented by formula 2, a group represented by formula 3, a group represented by formula 4, a group represented by formula 6, a combination of a group represented by formula 6 and a group represented by formula 7, and a heterocyclic group;

[0044] [ka]

[0045] In formula 2, R 4 -R 8 are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester group, C1-C 12 amine groups, preferably R 4 -R 8are each independently selected from H, halogen, hydroxy, amino, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy;

[0046] [ka]

[0047] In formula 3, R4-R 10 are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester group, C1-C 12 amine groups, preferably R-R 10 are each independently selected from H, halogen, hydroxy, amino, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, wherein the substituents are selected from halogen, hydroxy, amino, C1-C6 alkyl, C1-C6 alkoxy;

[0048] [ka]

[0049] In formula 4, R4'-R 10 ' are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester group, C1-C 12 amine groups, preferably R4'-R 10 each ' is independently selected from H, halogen, hydroxy, amino, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, wherein the substituents are selected from halogen, hydroxy, amino, C1-C6 alkyl, C1-C6 alkoxy;

[0050] [ka]

[0051] [ka]

[0052] In formula 6, R m is substituted or unsubstituted, C1-C 20 Straight chain alkyl, C3-C 20 Branched alkyl, C3-C 12 Cycloalkyl, C3-C 12 Epoxy alkyl, C3-C 12 The group is selected from the group consisting of epoxyalkylalkyl, the substituents of which are at least one selected from halogen, amino and hydroxyl.

[0053] More preferably, the alkenyl-containing polymerizable monomer is at least one selected from vinyl acetate, styrene, α-methylstyrene, (meth)acrylate, vinyl alkyl ether, vinylpyrrolidone, vinylpyridine, vinylimidazole, and acrylonitrile, and the (meth)acrylate is preferably at least one selected from methyl (meth)acrylate, ethyl (meth)acrylate, and glycidyl (meth)acrylate. Preferably, the alkenyl-containing polymerizable monomer is selected from vinyl acetate, styrene, and α-methylstyrene. More preferably, the alkenyl-containing polymerizable monomer is styrene.

[0054] The anhydride group-containing polypropylene graft of the present invention can be prepared by a method comprising the step of grafting a reaction mixture containing a polypropylene copolymer, a (maleic) anhydride monomer, and an alkenyl-containing polymerizable monomer in the presence of an inert gas (preferably a solid-phase grafting reaction) to obtain an anhydride group-containing polypropylene graft.

[0055] A second aspect of the present invention is a method for preparing an insulating material comprising an anhydride group-containing polypropylene graft, the method comprising the steps of: grafting a reaction mixture comprising a polypropylene copolymer, an anhydride monomer, and an alkenyl-containing polymerizable monomer in the presence of an inert gas to obtain the anhydride group-containing polypropylene graft; The graft reaction conditions are as follows: the content of structural units in the anhydride group-containing polypropylene graft, which are derived from the anhydride monomer and the alkenyl-containing polymerizable monomer and are in a grafted state, is 0.1 to 5 wt %, preferably 0.4 to 3 wt %, based on the weight of the anhydride group-containing polypropylene graft; and the molar ratio of the structural units derived from the anhydride monomer to the structural units derived from the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 1:1 to 20, preferably 1:1 to 10.

[0056] The polypropylene copolymer has at least one of the following characteristics: a comonomer content of 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; a xylene soluble content of 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; a comonomer content in the xylene solubles of 10 to 70 wt%, preferably 10 to 50 wt%, and more preferably 20 to 35 wt%; and an intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer of 0.3 to 5, preferably 0.5 to 3, and even more preferably 0.8 to 1.3.

[0057] Preferably, the content of structural units in the anhydride group-containing polypropylene graft that are derived from an anhydride monomer and are in a grafted state is 0.05 to 2% by weight, and more preferably 0.2 to 0.7% by weight.

[0058] Preferably, the anhydride is selected from anhydrides having at least one olefinic unsaturation. Preferably, the anhydride is selected from maleic anhydride and itaconic anhydride. More preferably, the acid anhydride is maleic anhydride.

[0059] Preferably, the present invention provides a method for preparing an anhydride group-containing polypropylene graft for an insulating material, the method comprising the steps of: grafting a reaction mixture containing a polypropylene copolymer, a maleic anhydride monomer, and an alkenyl-containing polymerizable monomer in the presence of an inert gas to obtain an anhydride group-containing polypropylene graft; The grafting reaction is carried out under the following conditions: the content of structural units in the anhydride group-containing polypropylene graft, which are derived from the maleic anhydride monomer and the alkenyl-containing polymerizable monomer and are in a grafted state, is 0.1 to 5 wt %, preferably 0.4 to 3 wt %, based on the weight of the anhydride group-containing polypropylene graft; and the molar ratio of the structural units derived from the maleic anhydride monomer to the structural units derived from the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 1:1 to 20, preferably 1:1 to 10.

[0060] The polypropylene copolymer has at least one of the following characteristics: a comonomer content of 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; a xylene soluble content of 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; a comonomer content in the xylene solubles of 10 to 70 wt%, preferably 10 to 50 wt%, and even more preferably 20 to 35 wt%; and an intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer of 0.3 to 5, preferably 0.5 to 3, and even more preferably 0.8 to 1.3.

[0061] Preferably, the content of structural units in the anhydride group-containing polypropylene graft that are derived from maleic anhydride monomer and are in a grafted state is 0.05 to 2% by weight, and more preferably 0.2 to 0.7% by weight.

[0062] The grafting reaction of the present invention can be carried out by various methods conventional in the art, preferably by solid-phase grafting reaction, e.g., by forming active grafting sites on a polypropylene copolymer in the presence of (maleic) anhydride monomer and an alkenyl-containing polymerizable monomer for grafting, or by forming active grafting sites on an initial polypropylene copolymer followed by treatment with a monomer for grafting. The grafting sites can be formed by treatment with a free radical initiator or by treatment with high-energy ionizing radiation or microwaves. Free radicals generated in the polymer as a result of chemical or radiation treatment form grafting sites on the polymer and initiate polymerization of the monomers at these sites.

[0063] Preferably, the grafting sites are initiated and the grafting reaction is furthered by a free radical initiator, in which case the reaction mixture comprises a free radical initiator, more preferably the free radical initiator is selected from a peroxide-based free radical initiator and / or an azo-based free radical initiator.

[0064] The peroxide-based free radical initiator is preferably at least one selected from dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, dodecyl peroxide, tert-butylperoxybenzoic acid, diisopropyl peroxydicarbonate, tert-butylperoxy(2-ethylhexanoate), and dicyclohexyl peroxydicarbonate; and the azo-based free radical initiator is preferably azobisisobutyronitrile and / or azobisisoheptonitrile.

[0065] More preferably, the grafting sites are initiated with a peroxide-based free radical initiator to further the grafting reaction.

[0066] Furthermore, the grafting reaction of the present invention can also be carried out according to the methods described in CN106543369A, CN104499281A, CN102108112A, CN109251270A, CN1884326A and CN101492517B.

[0067] The amount of each component used in the graft reaction of the present invention is not particularly limited, provided that the above-mentioned product characteristics are satisfied. Specifically, the ratio of the mass of the free radical initiator to the total mass of the (maleic) anhydride monomer and the alkenyl-containing polymerizable monomer is 0.1 to 10:100, preferably 0.5 to 5:100. The ratio of the total mass of the (maleic) anhydride monomer and the alkenyl-containing polymerizable monomer to the mass of the polypropylene copolymer is 0.1 to 8:100, preferably 0.3 to 5:100. The mass content of the (maleic) anhydride monomer may be 5 to 100 wt%, preferably 10 to 100 wt%, of the mass of the alkenyl-containing polymerizable monomer.

[0068] Furthermore, the present invention is not particularly limited to the technical conditions of the grafting reaction. Specifically, the grafting reaction temperature may be 30 to 130°C, preferably 60 to 120°C, and the reaction time may be 0.5 to 10 hours, preferably 1 to 5 hours.

[0069] In the present invention, the term "reaction mixture" includes all materials added to the grafting reaction system, which may be added all at once or at different stages of the reaction.

[0070] The reaction mixture of the present invention may also contain a dispersant, which is preferably water or an aqueous solution of sodium chloride. The mass content of the dispersant is preferably 50 to 300% of the mass of the polypropylene copolymer.

[0071] The reaction mixture of the present invention may further contain an interfacial agent. The interfacial agent is an organic solvent that has a swelling effect on polyolefins, preferably at least one selected from the following organic solvents that have a swelling effect on polypropylene copolymers: ether solvents, ketone solvents, aromatic hydrocarbon solvents, and alkane solvents; more preferably at least one selected from the following organic solvents: chlorobenzene, polychlorinated benzenes, alkanes or C6 or higher cycloalkanes, benzene, C1-C4 alkyl-substituted benzenes, C2-C6 fatty ethers, C3-C6 fatty ketones, and decalin; even more preferably at least one selected from the following organic solvents: benzene, toluene, xylene, chlorobenzene, tetrahydrofuran, diethyl ether, acetone, hexane, cyclohexane, decalin, and heptane. The mass content of the interfacial agent is preferably 1 to 30% of the mass of the polypropylene copolymer, more preferably 10 to 25%.

[0072] The reaction mixture of the present invention may further contain an organic solvent to dissolve the solid free radical initiator. The organic solvent preferably contains at least one selected from C2-C5 alcohols, C2-C4 ethers, and C3-C5 ketones, more preferably at least one selected from C2-C4 alcohols, C2-C3 ethers, and C3-C5 ketones, and most preferably at least one selected from ethanol, diethyl ether, and acetone. The mass content of the organic solvent is preferably 1 to 35% of the mass of the polypropylene copolymer.

[0073] In the method for preparing the anhydride group-containing polypropylene graft of the present invention, the definitions of the alkenyl-containing polymerizable monomer and the polypropylene copolymer are the same as those described above, and will not be described again here.

[0074] According to the present invention, the method for preparing the anhydride group-containing polypropylene grafts can be selected from the following: Method I, the preparation method, includes the following steps: (a) placing a polypropylene copolymer in a sealed reactor and then replacing the reactor with an inert gas; (b) adding a free radical initiator, an anhydride monomer, and an alkenyl-containing polymerizable monomer to a closed reactor and mixing with stirring; (c) optionally adding an interfacial agent and optionally swelling the reaction system; (d) optionally adding a dispersant and heating the reaction system to a grafting reaction temperature to carry out the grafting reaction; (e) After the reaction is complete, optionally filtering (if an aqueous phase dispersant is used) and drying to obtain the anhydride group-containing polypropylene graft.

[0075] More specifically, the preparation method includes the following steps: (a) placing a polypropylene copolymer in a sealed reactor and then replacing the reactor with an inert gas; (b) dissolving a free radical initiator in an anhydride monomer and an alkenyl-containing polymerizable monomer to obtain a solution, and adding the solution to a closed reactor containing the polypropylene copolymer and mixing with stirring; (c) adding 0 to 30 parts of an interfacial agent and optionally swelling the reaction system at 20 to 60°C for 0 to 24 hours; (d) adding 0 to 300 parts of a dispersant, heating the reaction system to a graft polymerization temperature of 30 to 130°C, and carrying out the reaction for 0.5 to 10 hours; (e) After the reaction is complete, optionally filtering (if an aqueous phase dispersant is used) and drying to obtain the anhydride group-containing polypropylene graft.

[0076] Method II, the preparation method, includes the steps of: (a) placing a polypropylene copolymer in a sealed reactor and then replacing the reactor with an inert gas; (b) mixing an organic solvent with a free radical initiator and adding the mixture to a closed reactor; (c) removing the organic solvent; (d) adding an anhydride monomer and an alkenyl-containing polymerizable monomer, optionally adding an interfacial agent, and optionally swelling the reaction system; (e) optionally adding a dispersant and heating the reaction system to a grafting reaction temperature to carry out the grafting reaction; (f) After the reaction is complete, optionally filtering (if an aqueous phase dispersant is used) and drying to obtain an anhydride group-containing polypropylene graft.

[0077] More specifically, the preparation method includes the following steps: (a) placing a polypropylene copolymer in a sealed reactor and then replacing the reactor with an inert gas; (b) mixing an organic solvent and a free radical initiator to obtain a solution, and adding the solution to a sealed reactor containing the polypropylene copolymer; (c) removing the organic solvent with an inert gas purge or vacuum; (d) adding an anhydride monomer and an alkenyl-containing polymerizable monomer, adding 0 to 30 parts of an interfacial agent, and optionally swelling the reaction system at 20 to 60°C for 0 to 24 hours; (e) adding 0 to 300 parts of a dispersant, heating to a graft polymerization temperature of 30 to 130°C, and carrying out a reaction for 0.5 to 10 hours; (f) After the reaction is complete, optionally filtering (if an aqueous phase dispersant is used) and drying to obtain an anhydride group-containing polypropylene graft.

[0078] According to the method of the present invention, if volatile components are present in the system after the reaction is completed, the method of the present invention preferably includes a step of removing the volatile components, which can be carried out by any conventional method, including vacuum extraction or the use of a stripping agent at the end of the grafting reaction. Suitable stripping agents include, but are not limited to, inert gases.

[0079] As described above, the term "anhydride group-containing polypropylene graft" in the present invention includes not only the product (crude product) directly obtained by the graft reaction of a polypropylene copolymer, an anhydride monomer, and an alkenyl-containing polymerizable monomer, but also the pure graft-modified polypropylene product obtained by further purifying the product. Therefore, the preparation method of the present invention optionally includes a step of purifying the crude product. Therefore, the preparation method of the present invention optionally includes a step of purifying the crude product. Purification can be carried out by various methods commonly used in the art, such as extraction.

[0080] Although the present invention does not particularly limit the grafting efficiency of the grafting reaction, a higher grafting efficiency is more advantageous for obtaining an anhydride group-containing polypropylene graft having desired properties in a single grafting reaction step. Therefore, the grafting efficiency of the grafting reaction is preferably controlled to 20 to 100%, more preferably 25 to 80%. The term "grafting efficiency" is well known to those skilled in the art and refers to the total amount of anhydride monomer and alkenyl-containing polymerizable monomer relative to the amount of grafts per total amount of anhydride monomer and alkenyl-containing polymerizable monomer added to the reaction.

[0081] The inert gas of the present invention can be a variety of inert gases commonly used in the art, including, but not limited to, nitrogen, argon.

[0082] A third aspect of the present invention is to provide an anhydride group-containing polypropylene graft for insulating materials obtained by the above preparation method.

[0083] A fourth aspect of the present invention provides the use of the anhydride group-containing polypropylene graft described above as an insulating material.

[0084] More preferably, the insulating material is a cable insulating material, preferably a DC cable insulating material.

[0085] More preferably, the insulating material is a cable insulation material.

[0086] The anhydride group-containing polypropylene graft used in the present invention can be used directly as a base material for insulating materials without blending with other polymers.

[0087] A fifth aspect of the present invention provides a cable comprising at least one conductor and at least one electrical insulating layer surrounding the conductor, the electrical insulating layer being made of an anhydride group-containing polypropylene graft.

[0088] The core of the present invention uses a novel material as the electrical insulation layer of the cable, and therefore the form and specific structure of the cable in the present invention are not particularly limited, and various cable forms (DC or AC, single-core or multi-core) and corresponding various structures conventional in the art can be used. In the cable of the present invention, except for the use of the novel graft-modified polypropylene material in the electrical insulation layer, other layer structures and other layer materials can be selected as conventional in the art.

[0089] The cable of the present invention may be a DC cable or an AC cable, preferably a DC cable, and more preferably the cable is a medium / high voltage DC cable or an extra-high voltage DC cable. In the present invention, low voltage (LV) refers to a voltage less than 1 kV, medium voltage (MV) refers to a voltage in the range of 1 kV to 40 kV, high voltage (HV) refers to a voltage greater than 40 kV, preferably greater than 50 kV, and extra-high voltage (EHV) refers to a voltage of at least 230 kV.

[0090] According to a preferred embodiment of the present invention, the cable has at least one cable core, and each cable core includes, from the inside to the outside, a conductor, an optional conductor shield layer, an electrical insulating layer, an optional electrical insulating shield layer, and an optional metallic shield layer. The conductor shield layer, the electrical insulating shield layer, and the metallic shield layer can be arranged as needed and are generally used for cables above 6 kV.

[0091] In addition to the above structure, the cable may further include an armor and / or sheath layer.

[0092] The cable of the present invention may be single-core or multi-core. In the case of a multi-core cable, the cable may further include a filling layer and / or a wrapping layer. The filling layer is formed by filling the spaces between the wire cores with a filling material. The wrapping layer covers the outside of all the wire cores, ensuring that the wire cores and the filling layer are round, preventing the wire cores from being scratched by the sheath, and providing a flame-retardant effect.

[0093] In the cable of the present invention, the conductor is a conductive element generally made of a metallic material, preferably aluminum, copper or other alloy containing one or more metal wires. The DC resistance and number of monofilaments of the conductor should meet the requirements of GB / T3956. Preferably, the conductor is 800 mm 2 It has a twisted round structure with a nominal cross-sectional area of ​​1000mm or less 2 The divided conductor structure has a nominal cross-sectional area of ​​170 or more, and the number of conductors is 170 or more.

[0094] In the cable of the present invention, the conductor shielding layer may be a cover layer made of polypropylene, polyolefin elastomer, carbon black, or other materials, and has a volume resistivity at 23°C of less than 1.0 Ω·m and a volume resistivity at 90°C of less than 3.5 Ω·m, a melt flow rate at 230°C under a 2.16 kg load of typically 0.01 to 30 g / 10 min, preferably 0.05 to 20 g / 10 min, more preferably 0.1 to 10 g / 10 min, and even more preferably 0.2 to 8 g / 10 min, a tensile strength of 12.5 MPa or greater, and an elongation at break of 150% or greater. The thickness of the thinnest point of the conductor shielding layer is 0.5 mm or greater, and the average thickness is 1.0 mm or greater.

[0095] In the cable of the present invention, the material of the electrical insulation layer is at least one anhydride-containing polypropylene graft, which means that the base material constituting the electrical insulation layer is an anhydride-containing polypropylene graft, and additional components, such as polymer components or additives, preferably additives, such as any one or more selected from antioxidants, stabilizers, processing aids, flame retardants, water tree retarding additives, acid or ion scavengers, inorganic fillers, voltage stabilizers, and copper inhibitors, may be included separately from the anhydride-containing polypropylene graft. The types and amounts of additives used are conventional and known to those skilled in the art.

[0096] The method for preparing the electrical insulation layer of the present invention may be a conventional method in the field of cable preparation, such as mixing an anhydride-group-containing polypropylene graft with various optional additives, granulating the mixture in a twin-screw extruder, and then extruding the resulting granules in an extruder to obtain an electrical insulation layer. Generally, the conductor shielding material can be co-extruded with the anhydride-group-containing polypropylene graft granules to form a structure of conductor shielding layer + electrical insulation layer, or a structure of conductor shielding layer + electrical insulation layer + electrical insulation shielding layer. Specific operations can be carried out using conventional methods and process conditions in the art.

[0097] By using an anhydride group-containing polypropylene graft, the thickness of the electrical insulation layer is only 50% to 95% of the nominal thickness value of the XLPE insulation layer in GB / T12706, preferably 70% to 90% of the nominal thickness value of the XLPE insulation layer in GB / T12706; the eccentricity is less than 10%.

[0098] In the cable of the present invention, the electrically insulating shielding layer may be a cover layer made of polypropylene, polyolefin elastomer, carbon black, or other materials, and has a volume resistivity at 23°C of less than 1.0 Ω·m and a volume resistivity at 90°C of less than 3.5 Ω·m, a melt flow rate at 230°C under a load of 2.16 kg of typically 0.01 to 30 g / 10 min, preferably 0.05 to 20 g / 10 min, more preferably 0.1 to 10 g / 10 min, and even more preferably 0.2 to 8 g / 10 min, a tensile strength of 12.5 MPa or greater, and an elongation at break of 150% or greater. The thickness of the electrically insulating shielding layer at its thinnest point is 0.5 mm or greater, and an average thickness is 1.0 mm or greater.

[0099] In the cable of the present invention, the metallic shielding layer may be a copper strip shielding layer or a copper wire shielding layer.

[0100] In the cable of the present invention, the filling layer can be made from high molecular weight polymeric materials such as PE / PP / PVC or recycled rubber materials.

[0101] In the cable of the present invention, the packaging layer / sheath is a metal cover layer that typically consists of a copper wire metal cage, a lead or aluminum metal sleeve, or the like, and wraps around the outer surface of the electrically insulating shielding layer, and is characterized by having a DC volume resistivity of 1000 Ω·m or less at room temperature.

[0102] In the cable of the present invention, the material of the sheath layer may be any one selected from polyvinyl chloride, polyethylene, and low-smoke halogen-free materials. The sheath layer includes not only an inner sheath layer but also an outer sheath layer.

[0103] The above-described structure of each layer can be formed by a conventional method in the art. For example, the conductive shielding layer, the electrical insulating layer, and the sheath layer can be formed by extrusion coating using an extruder, and the metallic shielding layer and the outer casing can be formed by winding.

[0104] The cable of the present invention can be prepared by various preparation methods commonly used in the art, and is not particularly limited in the present invention.

[0105] According to a specific embodiment of the present invention, the method for preparing the cable is as follows: Conductor preparation: A number of monofilament conductors (e.g., aluminum) are compacted and twisted to obtain a conductor core, or they are bundled together, and then the bundled monofilament conductors are twisted to obtain a conductor core.

[0106] Preparation of modified polypropylene particles: Anhydride group-containing polypropylene grafts are mixed with optional additives and granulated by a twin-screw extruder.

[0107] Preparation of conductor shielding layer and electrical insulation layer: Conductor shielding material and modified polypropylene particles are co-extruded and coated on the outside of the conductor inner core using an extruder to form a conductor shielding layer + electrical insulation layer or a conductor shielding layer + electrical insulation layer + electrical insulation shielding layer (outer shielding layer).

[0108] Preparation of the metal shielding layer: A copper strip or copper wire is wound around the outside of the electrical insulating layer (electrical insulating shielding layer) to form a metal shielding layer.

[0109] Preparation of inner sheath layer: The sheath layer granules are extruded onto the outside of the metal shielding layer using an extruder to form the inner sheath layer.

[0110] Sheath preparation: Prepare the steel wire or steel strip sheath using galvanized steel / stainless steel / aluminum alloy, and wind a single-layer sheath to the left around the inner sheath layer, or wind a double-layer sheath inner layer to the right and an outer layer to the left, so that the steel wire or steel strip sheath is dense and the gaps between adjacent steel wires / steel strips are minimized.

[0111] Preparation of outer sheath layer: The sheath layer granules are extruded onto the outside of the outer sheath using an extruder to form the outer sheath layer. Finally, the cable is prepared.

[0112] The anhydride group-containing polypropylene graft of the present invention can take into consideration both mechanical and electrical properties at higher use temperatures, and is suitable for use under high temperature and high operating field strength conditions. Furthermore, compared with materials containing small molecule additives, the anhydride group-containing polypropylene graft of the present invention can avoid performance degradation due to small molecule migration, and therefore has excellent stability.

[0113] The cable of the present invention can maintain and even have higher volume resistivity and stronger fracture resistance at higher operating temperatures than conventional cables, while the mechanical properties of the cable can meet the requirements for cable use. Under conditions ensuring the same voltage grade and insulation level, the electrical insulation layer made from an anhydride group-containing polypropylene graft has advantages such as thinner thickness, better heat dissipation, and lighter weight than the electrical insulation layer of conventional cables, thereby broadening the range of applications of the cable.

[0114] A sixth aspect of the present invention is to provide an insulating material, characterized in that the insulating material comprises at least one anhydride group-containing polypropylene graft as described above.

[0115] Preferably, the content of at least one anhydride group-containing polypropylene graft is 20 to 100% by weight, preferably 40 to 100% by weight, more preferably 60 to 100% by weight, even more preferably 80 to 100% by weight, and even more preferably 90 to 100% by weight, based on the weight of the insulating material.

[0116] Preferably, the insulating material further comprises additives such as one or more selected from antioxidants, stabilizers, processing aids, flame retardants, water tree retarding additives, acid or ion scavengers, inorganic fillers, voltage stabilizers, and copper inhibitors. The types and amounts of additives used are conventional and known to those skilled in the art.

[0117] Additionally, the present invention also includes the embodiments described in the following paragraphs.

[0118] (Section 1) A method for preparing an insulating material using an anhydride group-containing polypropylene graft, the method being characterized in that the anhydride group-containing polypropylene graft contains structural units derived from a polypropylene copolymer, structural units derived from an anhydride monomer, and structural units derived from an alkenyl-containing polymerizable monomer, the content of the structural units in the anhydride group-containing polypropylene graft, which are grafted from the anhydride monomer and the alkenyl-containing polymerizable monomer, is 0.1 to 5 wt %, preferably 0.4 to 3 wt %, based on the weight of the anhydride group-containing polypropylene graft, and the molar ratio of the structural units derived from the anhydride monomer to the structural units derived from the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 1:1 to 20, preferably 1:1 to 10; The polypropylene copolymer has at least one of the following characteristics: a comonomer content of 0.5 to 40 mol%, preferably 0.5 to 30 mol%, more preferably 4 to 25 wt%, and even more preferably 4 to 22 wt%; a xylene soluble content of 2 to 80 wt%, preferably 18 to 75 wt%, more preferably 30 to 70 wt%, and even more preferably 30 to 67 wt%; a comonomer content in the xylene solubles of 10 to 70 wt%, preferably 10 to 50 wt%, and more preferably 20 to 35 wt%; and an intrinsic viscosity ratio of the xylene solubles to the polypropylene copolymer of 0.3 to 5, preferably 0.5 to 3, and even more preferably 0.8 to 1.3.

[0119] (Section 2) The polypropylene copolymer according to the method of claim 1 has at least one of the following characteristics: a melt flow rate at 230°C under a load of 2.16 kg of 0.01 to 60 g / 10 min, preferably 0.05 to 35 g / 10 min, and more preferably 0.5 to 15 g / 10 min; a melting point Tm of 100°C or higher, preferably 110 to 180°C, more preferably 110 to 170°C, even more preferably 120 to 170°C, and still more preferably 120 to 166°C; a weight average molecular weight of preferably 20 x 10 4~60×10 4 g / mol.

[0120] (Section 3) 3. The method of claim 1 or 2, wherein the comonomer of the polypropylene copolymer is at least one selected from C2-C8 α-olefins other than propylene; preferably, the comonomer of the polypropylene copolymer is at least one selected from ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene; more preferably, the comonomer of the polypropylene copolymer is ethylene and / or 1-butene; and even more preferably, the polypropylene copolymer consists of propylene and ethylene.

[0121] (Section 4) 4. The method of any one of items 1 to 3, wherein the anhydride group-containing polypropylene graft is prepared by a solid-phase graft reaction of a polypropylene copolymer, an anhydride monomer, and an alkenyl-containing polymerizable monomer.

[0122] (Section 5) 5. The method according to any one of items 1 to 4, wherein the content of structural units derived from the anhydride monomer and in a grafted state in the anhydride group-containing polypropylene graft is 0.05 to 2% by weight, preferably 0.2 to 0.7% by weight.

[0123] (Section 6) 6. The method according to any one of items 1 to 5, wherein the anhydride is selected from anhydrides having at least one olefinic unsaturation, preferably the anhydride is selected from maleic anhydride and itaconic anhydride, more preferably the acid anhydride is maleic anhydride.

[0124] (Section 7) 7. The method according to any one of items 1 to 6, wherein the anhydride group-containing polypropylene graft has at least one of the following characteristics: a melt flow rate at 230°C under a load of 2.16 kg of 0.01 to 30 g / 10 min, preferably 0.05 to 20 g / 10 min, further preferably 0.1 to 10 g / 10 min, and more preferably 0.2 to 8 g / 10 min; a flexural modulus of 10 to 1050 MPa, preferably 20 to 1000 MPa, and more preferably 50 to 500 MPa; and an elongation at break of 200% or more, preferably 300% or more.

[0125] (Section 8) 8. The method of any one of items 1 to 7, wherein the anhydride group-containing polypropylene graft has at least one of the following characteristics: - the use temperature of the anhydride group-containing polypropylene graft is 90°C or higher, preferably 90 to 160°C; - Breakdown field strength E of the anhydride group-containing polypropylene graft at 90 ° C. g is 210 kV / mm or more, preferably 210 to 800 kV / mm; - Breakdown field strength E of the anhydride group-containing polypropylene graft at 90 ° C. g and the breakdown field strength E of the polypropylene copolymer at 90°C, divided by the breakdown field strength E of the polypropylene copolymer at 90°C, the rate of change in breakdown field strength ΔE / E exceeds 1.8%, preferably 2 to 50%, more preferably 5 to 35%, and even more preferably 8 to 28%; - DC volume resistivity ρ of the anhydride group-containing polypropylene graft at 90°C and 15 kV / mm field strength vg But 1.5 x 10 13 Ω.m or more, preferably 1.5×10 13 Ω.m~1.0×10 20 is Ω.m; - DC volume resistivity ρ of the polypropylene copolymer at 90°C and a field strength of 15 kV / mm v The direct current volume resistivity ρ of the anhydride group-containing polypropylene graft at 90 ° C. and 15 kV / mm field strengthvg The ratio (ρ vg / ρ v ) exceeds 2, and is preferably 2.1 to 40, more preferably 2.3 to 20, and even more preferably 2.5 to 10.

[0126] (Section 9) 9. The method according to any one of items 1 to 8, wherein the alkenyl-containing polymerizable monomer is at least one selected from monomers having a structure represented by formula 1.

[0127] [ka]

[0128] In formula 1, R b , R c , R d are each independently selected from H, substituted or unsubstituted alkyl; R a is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted ester group, substituted or unsubstituted carboxyl, substituted or unsubstituted cycloalkyl or heterocyclyl, cyano.

[0129] (Section 10) R b , R c , R d are each independently selected from H, substituted or unsubstituted C1-C6 alkyl; preferably, R b , R c , R d are each independently selected from H, substituted or unsubstituted C1-C3 alkyl; R a but substituted or unsubstituted C1-C 20 Alkyl, substituted or unsubstituted C1-C 20 Alkoxy, substituted or unsubstituted C6-C 20 Aryl, substituted or unsubstituted C1-C 20 Ester groups, substituted or unsubstituted C1-C 20 Carboxyl, substituted or unsubstituted C3-C 20cycloalkyl or heterocyclyl, cyano, the substituents of which are halogen, hydroxy, amino, C1-C6 alkyl, C3-C6 cycloalkyl; preferably, R a Substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C1-C 18 Alkoxy, substituted or unsubstituted C6-C 12 Aryl, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 Carboxyl, substituted or unsubstituted C3-C 12 cycloalkyl or heterocyclyl, cyano, the substituents of which are halogen, C1-C6 alkyl, C3-C6 cycloalkyl; more preferably, R a is substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C 12 Item 9. The method of claim 9, wherein the heterocyclyl is selected from alkoxy, substituted or unsubstituted C6-C8 aryl, substituted or unsubstituted C1-C6 ester group, substituted or unsubstituted C1-C6 carboxyl, substituted or unsubstituted C3-C6 cycloalkyl or heterocyclyl, cyano; preferably, the heterocyclyl is selected from imidazolyl, pyrazolyl, carbazolyl, pyrrolidinonyl, pyridyl, piperidinyl, caprolactam group, pyrazinyl, thiazolyl, purinyl, morpholinyl, and oxazolinyl.

[0130] (Section 11) R b , R c , R d are each independently selected from H, substituted or unsubstituted C1-C6 alkyl; R a is selected from a group represented by formula 2, a group represented by formula 3, a group represented by formula 4, a group represented by formula 6, a combination of a group represented by formula 6 and a group represented by formula 7, and a heterocyclic group;

[0131] [ka]

[0132] In formula 2, R 4 -R 8 are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester group, C1-C 12 amine groups; preferably, R 4 -R 8 are each independently selected from H, halogen, hydroxy, amino, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy;

[0133] [ka]

[0134] In formula 3, R4-R 10 are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester group, C1-C 12amine groups; preferably, R-R 10 are each independently selected from H, halogen, hydroxy, amino, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, wherein the substituents are selected from halogen, hydroxy, amino, C1-C6 alkyl, and C1-C6 alkoxy;

[0135] [ka]

[0136] In formula 4, R4'-R 10 ' are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C1-C 12 Alkyl, substituted or unsubstituted C3-C 12 Cycloalkyl, substituted or unsubstituted C1-C 12 Alkoxy, substituted or unsubstituted C1-C 12 Ester groups, substituted or unsubstituted C1-C 12 amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate, sulfonate, C1-C 12 Alkyl, C3-C 12 Cycloalkyl, C1-C 12 Alkoxy, C1-C 12 Ester group, C1-C 12 amine groups; preferably, R4'-R 10 each ' is independently selected from H, halogen, hydroxy, amino, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C1-C6 alkoxy, wherein the substituents are selected from halogen, hydroxy, amino, C1-C6 alkyl, C1-C6 alkoxy;

[0137] [ka]

[0138] [ka]

[0139] In formula 6, R m is substituted or unsubstituted, C1-C 20 Straight chain alkyl, C3-C 20 Branched alkyl, C3-C 12 Cycloalkyl, C3-C 12 Epoxy alkyl, C3-C 12 The alkyl group is selected from the group consisting of epoxy alkyl and alkyl having at least one substituent selected from halogen, amino and hydroxyl.

[0140] (Section 12) 10. The method of claim 9, wherein the alkenyl-containing polymerizable monomer is at least one selected from vinyl acetate, styrene, α-methylstyrene, (meth)acrylate, vinyl alkyl ether, vinylpyrrolidone, vinylpyridine, vinylimidazole, and acrylonitrile; the (meth)acrylate is preferably at least one selected from methyl (meth)acrylate, ethyl (meth)acrylate, and glycidyl (meth)acrylate; the alkenyl-containing polymerizable monomer is preferably selected from vinyl acetate, styrene, α-methylstyrene; and more preferably, the alkenyl-containing polymerizable monomer is styrene.

[0141] (Section 13) 13. A method according to any one of paragraphs 1 to 12, wherein the insulating material is a cable insulating material, preferably a DC cable insulating material.

[0142] (Section 14) 14. The method of claim 13, wherein the insulating material is a cable insulation layer material.

[0143] Additional features and advantages of the present invention are described in the detailed description of specific embodiments that follow.

[0144] [Mode for Carrying Out the Invention] Below is a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are intended to be illustrative and explanatory only and are not intended to be limiting of the present invention.

[0145] In the following examples and comparative examples: 1. Determination of comonomer content in polypropylene copolymer: Comonomer content was measured by quantitative Fourier transform infrared (FTIR) spectroscopy. The correlation of measured comonomer content was calibrated by quantitative nuclear magnetic resonance (NMR) spectroscopy. 13 Calibration methods based on results obtained from C-NMR spectroscopy were performed according to conventional methods in the art.

[0146] 2. Determination of the xylene solubles content in polypropylene copolymer, the comonomer content in xylene solubles, and the intrinsic viscosity ratio of xylene solubles to polypropylene copolymer: Measurements were made using a Polymer Char CRYST-EX instrument according to the following method: dissolve in trichlorobenzene solvent by heating to 150°C, hold for 90 minutes, sample and test, then cool to 35°C, hold for 70 minutes, sample and test.

[0147] 3. Measurement of weight average molecular weight of polypropylene copolymer: The sample was dissolved in 1,2,4-trichlorobenzene at a concentration of 1.0 mg / ml and analyzed by high-temperature GPC using a Polymer Laboratory PL-GPC 220 gel permeation chromatograph. The measurement temperature was 150°C and the solution flow rate was 1.0 ml / min. A calibration curve was plotted using the molecular weight of polystyrene as an internal standard, and the molecular weight and molecular weight distribution of the sample were calculated as a function of the elution time.

[0148] 4.Melt Flow Rate (MFR) Measurement: The measurements were carried out at 230°C under a load of 2.16 kg using a CEAST 7026 type melt indexer in accordance with the method specified in GB / T3682-2018.

[0149] 5. Melting point (Tm) measurement: The melting and crystallization processes of the materials were analyzed by differential scanning calorimetry. The specific procedure was as follows: Under nitrogen protection, 5-10 mg samples were measured using a three-step temperature ramp from 20°C to 200°C. The melting and crystallization processes of the materials were reflected in the changes in heat flow, and the melting point Tm was calculated.

[0150] 6. Measurement of Grafting Efficiency GE, Parameter M1, and Parameter M2: 2–4 g of the grafted product was placed in a Soxhlet extractor and extracted with ethyl acetate for 24 hours to remove unreacted monomers and homopolymers. The pure grafted product was obtained, which was then dried and weighed. The parameters M1, M2, and grafting efficiency (GE) were then calculated.

[0151] Maleic anhydride mass content %G MAH was tested and calculated according to the method described in the literature (Zhang Guangping, Solid-phase grafting of maleic anhydride onto polypropylene in helical ribbon reactor, China Plastics, Vol. 16, No. 2, February 2002, pp. 69-71).

[0152] The parameter M1 represents the content of structural units derived from maleic anhydride monomers and alkenyl-containing polymerizable monomers in the grafted state of the anhydride group-containing polypropylene graft, and the parameter M2 represents the content of structural units derived from maleic anhydride monomers in the grafted state of the anhydride group-containing polypropylene graft. The calculation formulas for M1, M2, and GE in the present invention are as follows:

[0153]

number

[0154]

number

[0155]

number

[0156] In the above formula, w0 represents the mass of the PP matrix, w1 represents the mass of the grafted product before extraction, w2 represents the mass of the grafted product after extraction, and w3 represents the total mass of the maleic anhydride monomer and the added alkenyl-containing polymerizable monomer.

[0157] 7. DC volume resistivity measurement: The measurements were carried out according to the method specified in GB / T1410-2006.

[0158] 8. Breakdown field strength measurement: The measurements were carried out according to the method specified in GB / T1408-2006.

[0159] 9. Tensile strength measurement: The measurements were carried out according to the method specified in GB / T1040.2-2006.

[0160] 10. Flexural modulus measurement: The measurements were carried out according to the method specified in GB / T9341-2008.

[0161] 11. Measurement of elongation at break: The measurements were carried out according to the method specified in GB / T1040-2006.

[0162] 12. Measurement of dielectric constant and dielectric loss tangent: The measurements were carried out according to the method specified in GB / T1409-2006.

[0163] 13. Measurement of cable main insulation conductivity (resistivity) ratio: The measurements were made according to the method specified in Appendix A of TICW 7.1-2012. The cable's main insulation conductivity ratio is equal to the cable's main insulation conductivity at 90°C divided by the cable's main insulation conductivity at 30°C.

[0164] 14. Field distortion measurement: Cable insulation space charge injection testing was performed according to the method specified in Appendix B of TICW 7.1-2012.

[0165] 15. DC withstand voltage test measurement: The cable was continuously pressurized at 1.85 times the negative rated voltage for 2 hours at room temperature. Breakdown and discharge events did not mean pass, otherwise it meant fail.

[0166] 16. Duty cycle measurement: The cables were heated to 90°C at their rated operating temperature and then subjected to a voltage of 1.85 times the rated voltage for 8 hours. The voltage was then removed and the cables were allowed to cool naturally for 16 hours. This cycle was repeated for 12 days. Failure does not mean a pass.

[0167] The materials used in the examples are listed in Table A below.

[0168] [Table 1]

[0169] *Polypropylene copolymer 1: Polypropylene copolymer used in Example 1, Comparative Example 2, and Comparative Example 3 *Polypropylene copolymer 2: the polypropylene copolymer used in Example 2 *Polypropylene copolymer 3: the polypropylene copolymer used in Example 3 *Polypropylene copolymer 4: the polypropylene copolymer used in Example 4 *Polypropylene copolymer 5: the polypropylene copolymer used in Example 5 *Polypropylene copolymer 6: the polypropylene copolymer used in Example 6 Example 1 A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt %, xylene solubles content of 48.7 wt %, comonomer content in the xylene solubles of 31.9 wt %, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 0.89, and weight average molecular weight of 34.3 × 10 4 The sample had a molecular weight of 1.21 g / mol, a MFR of 1.21 g / 10 min under a 2.16 kg load at 230 °C, a Tm of 143.4 °C, a breakdown field strength of 236 kV / mm at 90 °C, and a DC volume resistivity of 1.16E13 Ω / m at 90 °C and 15 kV / mm. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above base polypropylene copolymer powder was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and deoxygenated by nitrogen substitution. A solution of 1.3 g of dibenzoyl peroxide, 10 g of maleic anhydride, and 40 g of styrene was added, and the reaction mixture was mixed with stirring for 30 minutes, swelled at 40 °C for 2 hours, heated to 90 °C, and reacted for 4 hours. After completion of the reaction, the reaction product was cooled by nitrogen purging to obtain polypropylene-g-styrene / maleic anhydride material product C1.

[0170] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0171] <Example 2> A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 14.7 wt %, xylene solubles content of 41.7 wt %, comonomer content in the xylene solubles of 34.5 wt %, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 0.91, and weight average molecular weight of 36.6 × 10 4The polypropylene copolymer powder had a molecular weight of 1.54 g / mol, a MFR of 1.54 g / 10 min under a 2.16 kg load at 230 °C, a Tm of 164.9 °C, a breakdown field strength of 248 kV / mm at 90 °C, and a DC volume resistivity of 7.25E12 Ω·m at 90 °C and 15 kV / mm. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above base polypropylene copolymer powder was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and deoxygenated by nitrogen substitution. A solution of 0.6 g of dibenzoyl peroxide, 5 g of maleic anhydride, and 22 g of styrene was added, and the reaction mixture was mixed with stirring for 30 minutes, swelled at 40 °C for 3 hours, heated to 95 °C, and reacted for 4 hours. After the reaction was complete, the reaction product was cooled by nitrogen purging to obtain polypropylene-g-styrene / maleic anhydride material product C2.

[0172] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0173] Example 3 A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 20.1 wt %, xylene solubles content of 66.1 wt %, comonomer content in the xylene solubles of 29.5 wt %, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 1.23, and weight average molecular weight of 53.8 × 10 4The polypropylene copolymer powder had a molecular weight of 0.51 g / mol under a 2.16 kg load at 230 °C, a thermal conductivity of 142.5 °C, a breakdown field strength of 176 kV / mm at 90 °C, and a DC volume resistivity of 5.63E12 Ω·m at 90 °C and 15 kV / mm. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above base polypropylene copolymer powder was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and deoxygenated by nitrogen substitution. A solution of 2.6 g of dibenzoyl peroxide, 12 g of maleic anhydride, and 88 g of styrene was added, and the reaction mixture was mixed with stirring for 30 minutes, swelled at 40 °C for 2 hours, heated to 90 °C, and reacted for 4 hours. After the reaction was complete, the reaction product was cooled by nitrogen purging to obtain polypropylene-g-styrene / maleic anhydride material product C3.

[0174] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0175] Example 4 A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 9.3 wt%, xylene solubles content of 21.0 wt%, comonomer content in the xylene solubles of 35.4 wt%, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 1.68, and weight average molecular weight of 30.4 × 10 4The powder had a MFR of 5.69 g / mol under a 2.16 kg load at 230 °C, a Tm of 163.0 °C, a breakdown field strength of 288 kV / mm at 90 °C, and a DC volume resistivity of 1.32E13 Ω / m at 90 °C and 15 kV / mm. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above basic polypropylene copolymer powder was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and deoxygenated by nitrogen substitution. A solution of 5.0 g of tert-butylperoxy(2-ethylhexanoate), 25 g of maleic anhydride, 50 g of vinyl acetate, and 100 g of toluene was added. The reaction mixture was stirred for 30 minutes, heated to 95 °C, and reacted for 4 hours. After the reaction was completed, the reaction product was cooled by nitrogen purging to obtain polypropylene-g-vinyl acetate / maleic anhydride material product C4.

[0176] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0177] <Example 5> A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 4.8 wt%, xylene solubles content of 19.2 wt%, comonomer content in the xylene solubles of 17.6 wt%, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 1.04, and weight average molecular weight of 29.2 × 10 4The polypropylene copolymer powder had a molecular weight of 5.37 g / mol, a MFR of 5.37 g / 10 min under a 2.16 kg load at 230 °C, a Tm of 163.3 °C, a breakdown field strength of 322 kV / mm at 90 °C, and a DC volume resistivity of 1.36E13 Ω·m at 90 °C and 15 kV / mm. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above base polypropylene copolymer powder was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and deoxygenated by nitrogen substitution. A solution of 0.6 g of dibenzoyl peroxide, 10 g of maleic anhydride, 11 g of styrene, and 50 g of toluene was added, and the reaction mixture was mixed with stirring for 30 minutes, swelled at 50 °C for 2 hours, and then heated to 100 °C and reacted for 1 hour. After completion of the reaction, the reaction product was cooled by nitrogen purging to obtain polypropylene-g-styrene / maleic anhydride material product C5.

[0178] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0179] Example 6 A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 12.6 wt%, xylene solubles content of 30.6 wt%, comonomer content in the xylene solubles of 43.6 wt%, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 1.84, and weight average molecular weight of 27.1 × 10 4The molecular weight (MFR) was 8.46 g / mol under a 2.16 kg load at 230°C, Tm was 162.0°C, the breakdown field strength at 90°C was 261 kV / mm, and the DC volume resistivity at 90°C and 15 kV / mm was 9E12 Ω·m. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above basic polypropylene copolymer powder was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and oxygen was removed by nitrogen substitution. 2g of lauroyl peroxide and 20g of maleic anhydride were dissolved in 150g of acetone, the resulting acetone solution was added to the reaction system, heated to 50°C, and acetone was removed by nitrogen purging for 30 minutes. 60g of α-methylstyrene was added dropwise to the reaction kettle, and the solution was mixed with stirring for 30 minutes, swollen at 40°C for 2 hours, heated to 85°C, and 4kg of dispersant water was added at 85°C, and the reaction was carried out for 2 hours. After the reaction was completed, the reaction product was cooled, filtered to remove the dispersant water, and vacuum dried at 70°C for 10 hours to obtain polypropylene-g-α-methylstyrene / maleic anhydride raw material product C6.

[0180] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0181] Example 7 2.0 kg of the base polypropylene copolymer powder from Example 1 was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and purged with nitrogen to remove oxygen. A solution of 4.0 g of dibenzoyl peroxide, 30 g of maleic anhydride, and 120 g of styrene was added, and the reaction mixture was mixed with stirring for 30 minutes, swelled at 40°C for 2 hours, heated to 90°C, and reacted for 4 hours. After the reaction was complete, the reaction product was cooled with nitrogen purging to obtain polypropylene-g-styrene / maleic anhydride product C7.

[0182] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0183] <Comparative Example 1> After sieving to remove fine particles smaller than 40 mesh, 2.0 kg of T30S powder (breakdown field strength at 90°C: 347 kV / mm, DC volume resistivity at 90°C and 15 kV / mm: 1.18E13 Ω·m) was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and oxygen was removed by nitrogen substitution. A solution of 1.3 g of dibenzoyl peroxide, 10 g of maleic anhydride, and 40 g of styrene was added, and the reaction mixture was mixed with stirring for 60 minutes, swelled at 40°C for 2 hours, heated to 90°C, and reacted for 4 hours. After the reaction was complete, the reaction product was cooled by nitrogen purging to obtain polypropylene-g-styrene / maleic anhydride material product D1.

[0184] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0185] <Comparative Example 2> A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt %, xylene solubles content of 48.7 wt %, comonomer content in the xylene solubles of 31.9 wt %, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 0.89, and weight average molecular weight of 34.3 × 10 4 The polypropylene copolymer powder had a molecular weight of 1.21 g / mol, a MFR of 1.21 g / 10 min under a 2.16 kg load at 230 °C, a Tm of 143.4 °C, a breakdown field strength of 236 kV / mm at 90 °C, and a DC volume resistivity of 1.16E13 Ω / m at 90 °C and 15 kV / mm. Fine powder smaller than 40 mesh was removed by sieving. 2.0 kg of the above base polypropylene copolymer powder was weighed and added to a 10 L reactor equipped with a mechanical stirrer. The reaction system was sealed and deoxygenated by nitrogen substitution. A solution of 5 g of dibenzoyl peroxide, 40 g of maleic anhydride, and 160 g of styrene was added, and the reaction mixture was mixed with stirring for 60 minutes, swelled at 40 °C for 2 hours, heated to 90 °C, and reacted for 4 hours. After completion of the reaction, the reaction product was cooled by nitrogen purging to obtain polypropylene-g-styrene / maleic anhydride material product D2.

[0186] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0187] <Comparative Example 3> A base polypropylene copolymer powder was selected with the following characteristics: comonomer ethylene content of 18.1 wt %, xylene solubles content of 48.7 wt %, comonomer content in the xylene solubles of 31.9 wt %, intrinsic viscosity ratio of xylene solubles to polypropylene copolymer of 0.89, and weight average molecular weight of 34.3 × 10 4 The molecular weight (MFR) was 1.21 g / mol at 230°C under a 2.16 kg load, Tm was 143.4°C, the breakdown field strength at 90°C was 236 kV / mm, and the DC volume resistivity at 90°C and 15 kV / mm was 1.16E13 Ω / m. Fine powder smaller than 40 mesh was removed by sieving. 2000 g of the above base polypropylene copolymer powder was weighed and mixed with 50 g of styrene / maleic anhydride copolymer in a screw extruder to obtain Blend D3.

[0188] The resulting product was tested for various performance parameters and the results are shown in Table 1.

[0189] [Table 2]

[0190] remarks: M1 represents the content of structural units in the anhydride group-containing polypropylene graft that are derived from maleic anhydride monomers and alkenyl-containing polymerizable monomers and are in a grafted state. M2 indicates the content of structural units in the anhydride group-containing polypropylene graft that are derived from maleic anhydride monomers and remain grafted. The breakdown field strength change rate ΔE / E is the ratio of the breakdown field strength E of the anhydride group-containing polypropylene graft product at 90°C to the breakdown field strength E of the base polypropylene copolymer powder at 90°C. gThe figure shows the ratio obtained by multiplying the difference ΔE between the breakdown field strength E of the base polypropylene copolymer powder at 90°C and that of the base polypropylene copolymer powder at 90°C by 100%. ρ vg refers to the DC volume resistivity of the anhydride group-containing polypropylene graft product at 90°C and a field strength of 15 kV / mm, and ρ vg / ρ v is the DC volume resistivity ρ of the basic polypropylene copolymer powder at 90°C and 15 kV / mm electric field strength. v DC volume resistivity ρ of an anhydride group-containing polypropylene graft product at 90°C and 15 kV / mm field strength, vg Refers to the percentage of

[0191] Comparing the data of Example 1 and Comparative Example 1, it can be seen that using T30S powder as the base powder results in a polypropylene-g-styrene / maleic anhydride material product with too high a flexural modulus and poor mechanical properties that cannot meet the processing requirements of insulating materials.

[0192] By comparing the data of Example 1 and Comparative Example 2, it can be seen that excessive addition of maleic anhydride monomer / alkenyl-containing polymerizable monomer (too high M value) results in a decrease in the breakdown field strength and volume resistivity of the resulting polypropylene-g-styrene / maleic anhydride material product, affecting the electrical properties of the product.

[0193] By comparing the data of Example 1 and Comparative Example 3, it can be seen that blending styrene / maleic anhydride copolymer significantly reduces the breakdown field strength and volume resistivity of the product, significantly affecting the electrical properties of the product.

[0194] In conclusion, as can be seen from the data in Table 1, the anhydride group-containing polypropylene grafts of the present invention have good mechanical properties due to a significant reduction in flexural modulus, and the breakdown field strengths of the grafted products are all improved compared to the ungrafted polypropylene copolymers using maleic anhydride monomer / alkenyl-containing polymerizable monomer, which also indicates that the anhydride group-containing polypropylene grafts of the present invention have good electrical properties.

[0195] Furthermore, as can be seen from the dielectric constant and dielectric loss data, the graft modification does not affect the dielectric constant and dielectric loss of the material, and the material of the present invention meets the requirements for an insulating material.

[0196] Example A Conductor preparation: A large number of aluminum monofilament conductors are wired and processed into a bundle, and then the bundled monofilament conductors are prepared into a conductor core.

[0197] Preparation of anhydride group-containing polypropylene graft particles: 100 parts by mass of the anhydride group-containing polypropylene grafts obtained in Examples C1, C3, C5, and C7 and 0.3 parts by mass of antioxidant 1010 / 168 / calcium stearate (mass ratio: 2:2:1) are blended and granulated in a twin-screw extruder at a rotation speed of 300 r / min and a granulation temperature of 210 to 230°C.

[0198] Preparation of the conductor shielding layer and electrical insulation layer: The conductor shielding material PSD_WMP-00012 (Zhejiang Wanma Co., Ltd.) and the anhydride-group-containing polypropylene graft particles were coextruded onto the outer surface of the conductor core to form either a conductor shielding layer plus an electrical insulation layer, or a conductor shielding layer plus an electrical insulation layer plus an electrical insulation shielding layer (outer shielding layer). The extrusion temperature was 160-210°C.

[0199] Preparation of metal shielding layer: Using T1 copper, a copper strip is wound around the outside of the electrical insulation layer (electrical insulation shielding layer) to form a metal shielding layer.

[0200] Preparation of the inner sealing layer: St-2 PVC granules (Dongguan Haichuang Electronics Co., Ltd.) are extruded onto the outside of the metal shielding layer using an extruder to form the inner sheath layer.

[0201] Sheath preparation: A steel wire sheath with a nominal diameter of 1.25 mm is prepared using 304 stainless steel, and the single-layer sheath is wound counterclockwise around the inner sheath layer so that the sheath is dense and the gaps between adjacent steel wires are minimized.

[0202] Preparation of outer sheath layer: St-2 PVC granules (Dongguan Haichuang Electronics Co., Ltd.) are extruded onto the outside of the outer sheath using an extruder to form the outer sheath layer.

[0203] The final result was a cable with a high-performance polypropylene insulation layer, the cross section of which is shown in Figure 1.

[0204] According to the above method, cables having an energy level in the range of 6 to 35 kV were prepared based on the materials of Examples C1, C3, C5 and C7, respectively. The cross-sectional area of ​​the conductor in the cable was 240 to 400 mm 2 The thickness of the conductive shielding layer was 1 to 3 mm, the thickness of the electrical insulating layer was 2 to 8 mm, the thickness of the electrical insulating shielding layer was 0.5 to 1.5 mm, the thickness of the outer sheath was 0.5 to 1 mm, the thickness of the inner sheath layer was 1 to 2 mm, and the thickness of the outer sheath layer was 1.8 mm or more.

[0205] <Test Example A> The cables prepared in Example B were tested. Results of the cable main insulation conductivity test: The conductivity ratio of each cable at 90°C and 30°C was less than 100. Results of the cable insulation space charge injection test: The electric field distortion rate of each cable was less than 20%. Results of the DC withstand voltage test: Each cable had no breakdown or discharge phenomena and passed the test. Results of the load cycle test: Each cable had no breakdown phenomena and passed the test.

[0206] Example A1 Conductor preparation: 76 aluminum monofilaments with a diameter of 2.5 mm were compacted and twisted to obtain an aluminum conductor core.

[0207] Preparation of anhydride group-containing polypropylene graft particles: 100 parts by mass of the anhydride group-containing polypropylene graft obtained in Example 2 and 0.3 parts by mass of antioxidant 1010 / 168 / calcium stearate (mass ratio: 2:2:1) were blended and granulated in a twin-screw extruder at a rotation speed of 300 r / min and a granulation temperature of 210 to 230°C.

[0208] Preparation of the conductor shielding layer and electrical insulation layer: The conductor shielding material PSD_WMP-00012 (Zhejiang Wanma Co., Ltd.) and the anhydride-group-containing polypropylene graft particles were coextruded onto the outer surface of the conductor core to form either a conductor shielding layer plus an electrical insulation layer, or a conductor shielding layer plus an electrical insulation layer plus an electrical insulation shielding layer (outer shielding layer). The extrusion temperature was 190-210°C.

[0209] Preparation of the metal shielding layer: Using 25 T1 copper wires with a diameter of 0.3 mm, wind the copper wire around the outside of the electrical insulation layer (electrical insulation shielding layer) to form a metal shielding layer.

[0210] Preparation of the inner sheath layer: St-2 PVC granules (Dongguan Haichuang Electronics Co., Ltd.) are extruded onto the outside of the metal shielding layer using an extruder to form the inner sheath layer.

[0211] Preparation of the sheath: Prepare the steel wire sheath using 50 pieces of 6.0 mm diameter 304 stainless steel wire, and wind the single-layer sheath around the inner sheath layer in a left-handed direction so that the sheath is dense and the gaps between adjacent steel wires are minimized.

[0212] Preparation of outer sheath layer: St-2 PVC granules (Dongguan Haichuang Electronics Co., Ltd.) are extruded onto the outside of the outer sheath using an extruder to form the outer sheath layer.

[0213] The final result was a cable with a high-performance polypropylene insulation layer, the cross section of which is shown in Figure 1.

[0214] According to the above method, a cable with an energy level of 10 kV was prepared based on the material of Example 2. The cross-sectional area of ​​the conductor in the cable was about 400 mm 2 The average thickness of the conductor shielding layer was 1.15 mm, the average thickness of the electrical insulating layer was 2.60 mm, the average thickness of the electrical insulating shielding layer was 1.06 mm, the average thickness of the metallic shielding layer was 1.00 mm, the cable insulation eccentricity was 5.1%, the average thickness of the outer jacket was 6.02 mm, the average thickness of the inner sheath layer was 2.10 mm, and the average thickness of the outer sheath layer was 2.35 mm.

[0215] <Test Example A1> The adjusted cable was tested. Result of cable main insulation conductivity test: The conductivity ratio of the cable at 90°C and 30°C was 44.2. Result of cable insulation space charge injection test: The electric field distortion factor of the cable was 15.4%. Result of DC withstand voltage test: The cable had no breakdown or discharge phenomena and passed the test. Result of load cycle test: The cable had no breakdown phenomena and passed the test.

[0216] It has been found that the cable containing the anhydride group-containing polypropylene graft as the main insulation layer of the present invention has a higher operating temperature than existing cables, and can still maintain a higher volume resistivity and stronger fracture resistance even at higher operating temperatures. Under conditions ensuring the same voltage grade and insulation level, the electrical insulation layer made from the anhydride group-containing polypropylene graft has the advantages of being thinner, having better heat dissipation properties, and being lighter in weight than the electrical insulation layer of conventional cables.

[0217] Although the embodiments of the present invention have been described above, the above description is illustrative and not exhaustive, and the present invention is not limited to the embodiments. Many improvements and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the embodiments.

[0218] The endpoints of the ranges and any values ​​disclosed herein should be understood not to be limited to the exact range or value, but to encompass values ​​close to those ranges or values. For numerical ranges, the endpoints of the ranges, the endpoints of the ranges and individual point values, and the individual point values ​​can be combined with each other to create one or more new numerical ranges, which should be considered to be specifically disclosed herein. [Brief explanation of the drawings]

[0219] [Figure 1] FIG. 1 is a schematic cross-sectional view of a cable according to one embodiment of the present invention.

Claims

1. 1. An anhydride group-containing polypropylene graft for insulating materials, comprising: The polymerizable composition comprises structural units derived from a polypropylene copolymer, structural units derived from an anhydride monomer, and structural units derived from an alkenyl-containing polymerizable monomer; the content of structural units in the anhydride group-containing polypropylene graft, which are derived from the anhydride monomer and the alkenyl-containing polymerizable monomer and are in a grafted state, is 0.1 to 5 wt % based on the weight of the anhydride group-containing polypropylene graft; the molar ratio of the structural units derived from the alkenyl-containing polymerizable monomer to the structural units derived from the anhydride monomer in the anhydride group-containing polypropylene graft is 1:1 to 20; The polypropylene copolymer has at least one of the following characteristics: The comonomer content is 0.5 to 40 mol%; The content of xylene solubles is 2 to 80% by weight; The content of the comonomer in the xylene soluble matter is 10 to 70% by weight; the ratio of the intrinsic viscosity of the xylene soluble material to the polypropylene copolymer is 0.3 to 5; The alkenyl-containing polymerizable monomer is at least one selected from monomers having a structure represented by Formula 1, 【Chemical 1】 In formula 1, R b , R c , and R d are each independently selected from H, substituted or unsubstituted alkyl; and R a is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted ester group, substituted or unsubstituted carboxyl, substituted or unsubstituted cycloalkyl or heterocyclyl, and cyano.

2. the content of grafted structural units derived from the anhydride monomer and the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 0.4 to 3 wt. % based on the weight of the anhydride group-containing polypropylene graft; and / or The anhydride group-containing polypropylene graft according to claim 1, wherein the molar ratio of the structural units derived from the alkenyl-containing polymerizable monomer to the structural units derived from the anhydride monomer in the anhydride group-containing polypropylene graft is 1:1-10.

3. The polypropylene copolymer according to claim 1 or 2, wherein the polypropylene copolymer has at least one of the following characteristics: the comonomer content is 0.5 to 30 mol%, or 4 to 25 wt%, or 4 to 22 wt%; the xylene solubles content is 18 to 75 wt%, or 30 to 70 wt%, or 30 to 67 wt%; the content of the comonomer in the xylene soluble matter is 10 to 50% by weight, or 20 to 35% by weight; The ratio of the intrinsic viscosity of the xylene solubles to the polypropylene copolymer is 0.5 to 3, or 0.8 to 1.

3.

4. The anhydride group-containing polypropylene graft according to any one of claims 1 to 3, wherein the polypropylene copolymer has at least one of the following characteristics: a melt flow rate under a load of 2.16 kg at 230°C of 0.01 to 60 g / 10 min, or 0.05 to 35 g / 10 min, or 0.5 to 15 g / 10 min; The melting point Tm is 100°C or higher, or 110 to 180°C, or 110 to 170°C, or 120 to 170°C, or 120 to 166°C; Weight average molecular weight is 20 x 10 ４ ~60 x 10 ４ g / mol.

5. The comonomer of the polypropylene copolymer is a C copolymer other than propylene. ２ -C ８ The anhydride group-containing polypropylene graft according to any one of claims 1 to 4, wherein the α-olefin is at least one selected from the following α-olefins:

6. The anhydride group-containing polypropylene graft according to any one of claims 1 to 4, wherein the comonomer of the polypropylene copolymer is at least one selected from ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, and 1-octene.

7. The anhydride group-containing polypropylene graft of any one of claims 1 to 6, prepared by a solid-phase graft reaction of a polypropylene copolymer, an anhydride monomer and an alkenyl-containing polymerizable monomer.

8. The anhydride group-containing polypropylene graft according to any one of claims 1 to 7, wherein the content of structural units derived from the anhydride monomer and in a grafted state in the anhydride group-containing polypropylene graft is 0.05 to 2 wt%, or 0.2 to 0.7 wt%.

9. An anhydride group-containing polypropylene graft according to any one of claims 1 to 8, wherein said anhydride monomer is selected from anhydrides having at least one olefinic unsaturation.

10. An anhydride group-containing polypropylene graft according to any one of claims 1 to 8, wherein said anhydride monomer is selected from maleic anhydride and itaconic anhydride.

11. An anhydride group-containing polypropylene graft according to any one of claims 1 to 10, having at least one of the following characteristics: a melt flow rate under a load of 2.16 kg at 230°C of 0.01 to 30 g / 10 min, or 0.05 to 20 g / 10 min, or 0.1 to 10 g / 10 min, or 0.2 to 8 g / 10 min; a flexural modulus of 10 to 1050 MPa, or 20 to 1000 MPa, or 50 to 500 MPa; The elongation at break is 200% or more, or 300% or more.

12. An anhydride group-containing polypropylene graft according to any one of claims 1 to 11, having at least one of the following characteristics: The use temperature of the anhydride group-containing polypropylene graft is 90°C or higher, or 90 to 160°C; The breakdown field strength E of the anhydride group-containing polypropylene graft at 90°C ｇ is 210 kV / mm or more, or 210 to 800 kV / mm; The breakdown field strength E of the anhydride group-containing polypropylene graft at 90°C ｇ and the breakdown field strength E of the polypropylene copolymer at 90°C, divided by the breakdown field strength E of the polypropylene copolymer at 90°C, the rate of change in breakdown field strength ΔE / E is greater than 1.8%, or 2 to 50%, or 5 to 35%, or 8 to 28%; The direct current volume resistivity ρ of the anhydride group-containing polypropylene graft at 90°C and 15 kV / mm electric field strength ｖｇ is 1.5 x 10 １３ Ω.m or more, or 1.5 x 10 １３ Ω.m ~ 1.0 x 10 ２０ Ω.m; The direct current volume resistivity ρ of the polypropylene copolymer at 90°C and an electric field strength of 15 kV / mm ｖ The direct current volume resistivity ρ of the anhydride group-containing polypropylene graft at 90 ° C. and 15 kV / mm electric field strength ｖｇ The ratio (ρ ｖｇ / ρ ｖ ) is greater than 2, or 2.1 to 40, or 2.3 to 20, or 2.5 to 10.

13. R ｂ , R ｃ , R ｄ are each independently H, substituted or unsubstituted C １ -C ６ alkyl; R ａ is substituted or unsubstituted C １ -C ２０ Alkyl, substituted or unsubstituted C １ -C ２０ Alkoxy, substituted or unsubstituted C ６ -C ２０ Aryl, substituted or unsubstituted C １ -C ２０ an ester group, substituted or unsubstituted C １ -C ２０ Carboxyl, substituted or unsubstituted C ３ -C ２０ cycloalkyl or heterocyclyl, cyano, the substituents of which are halogen, hydroxy, amino, C １ -C ６ Alkyl, C ３ -C ６ 2. The anhydride group-containing polypropylene graft of claim 1, which is cycloalkyl.

14. R ｂ , R ｃ , R ｄ are each independently H, substituted or unsubstituted C １ -C ３ alkyl; and / or R ａ is substituted or unsubstituted C １ -C １２ Alkyl, substituted or unsubstituted C １ -C １８ Alkoxy, substituted or unsubstituted C ６ -C １２ Aryl, substituted or unsubstituted C １ -C １２ an ester group, substituted or unsubstituted C １ -C １２ Carboxyl, substituted or unsubstituted C ３ -C １２ cycloalkyl or heterocyclyl, cyano, the substituents of which are halogen, C １ -C ６ Alkyl, C ３ -C ６ is cycloalkyl; and / or 14. The polypropylene graft containing anhydride groups according to claim 13, wherein said heterocyclyl is selected from imidazolyl, pyrazolyl, carbazolyl, pyrrolidinonyl, pyridyl, piperidinyl, caprolactam group, pyrazinyl, thiazolyl, purinyl, morpholinyl, oxazolinyl.

15. R ｂ , R ｃ , R ｄ are each independently H, substituted or unsubstituted C １ -C ６ alkyl; R ａ is selected from a group represented by formula 2, a group represented by formula 3, a group represented by formula 4, a group represented by formula 6, a combination of a group represented by formula 6 and a group represented by formula 7, and a heterocyclic group: 【Chemistry 2】 In formula 2, R ４ -R ８ are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C １ -C １２ Alkyl, substituted or unsubstituted C ３ -C １２ Cycloalkyl, substituted or unsubstituted C １ -C １２ Alkoxy, substituted or unsubstituted C １ -C １２ an ester group, substituted or unsubstituted C １ -C １２ amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate groups, sulfonate groups, C １ -C １２ Alkyl, C ３ -C １２ Cycloalkyl, C １ -C １２ Alkoxy, C １ -C １２ Ester group, C １ -C １２ amine groups; 【Chemistry 3】 In formula 3, R ４ -R １０ are each independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C １ -C １２ Alkyl, substituted or unsubstituted C ３ -C １２ Cycloalkyl, substituted or unsubstituted C １ -C １２ Alkoxy, substituted or unsubstituted C １ -C １２ an ester group, substituted or unsubstituted C １ -C １２ amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate groups, sulfonate groups, C １ -C １２ Alkyl, C ３ -C １２ Cycloalkyl, C １ -C １２ Alkoxy, C １ -C １２ Ester group, C １ -C １２ amine groups; 【Chemistry 4】 In formula 4, R ４ '-R １０ Each ' is independently H, halogen, hydroxy, amino, phosphate, sulfonate, substituted or unsubstituted C １ -C １２ Alkyl, substituted or unsubstituted C ３ -C １２ Cycloalkyl, substituted or unsubstituted C １ -C １２ Alkoxy, substituted or unsubstituted C １ -C １２ an ester group, substituted or unsubstituted C １ -C １２ amine groups, the substituents of which are selected from halogen, hydroxy, amino, phosphate groups, sulfonate groups, C １ -C １２ Alkyl, C ３ -C １２ Cycloalkyl, C １ -C １２ Alkoxy, C １ -C １２ Ester group, C １ -C １２ amine groups; 【Chemistry 5】 【Chemistry 6】 In formula 6, R ｍ is substituted or unsubstituted, C １ -C ２０ Straight chain alkyl, C ３ -C ２０ Branched alkyl, C ３ -C １２ Cycloalkyl, C ３ -C １２ Epoxy alkyl, C ３ -C １２ The alkyl group is selected from the group consisting of epoxy alkyl and alkyl having at least one substituent selected from halogen, amino and hydroxyl.

16. In the formula 2, R ４ -R ８ are each independently H, halogen, hydroxy, amino, substituted or unsubstituted C １ -C ６ Alkyl, substituted or unsubstituted C １ -C ６ alkoxy; and / or In the formula 3, R ４ -R １０ are each independently H, halogen, hydroxy, amino, substituted or unsubstituted C １ -C ６ Alkyl, substituted or unsubstituted C １ -C ６ alkoxy, the substituents of which are halogen, hydroxy, amino, C １ -C ６ Alkyl, C １ -C ６ alkoxy; and / or In the formula 4, R ４ '-R １０ Each ' is independently H, halogen, hydroxy, amino, substituted or unsubstituted C １ -C ６ Alkyl, substituted or unsubstituted C １ -C ６ alkoxy, the substituents of which are halogen, hydroxy, amino, C １ -C ６ Alkyl, C １ -C ６ 16. The anhydride group-containing polypropylene graft of claim 15, wherein the anhydride group-containing polypropylene graft is selected from alkoxy.

17. the alkenyl-containing polymerizable monomer is at least one selected from vinyl acetate, styrene, α-methylstyrene, (meth)acrylate, vinyl alkyl ether, vinylpyrrolidone, vinylpyridine, vinylimidazole, and acrylonitrile; 2. The anhydride group-containing polypropylene graft according to claim 1, wherein the (meth)acrylate is at least one selected from methyl (meth)acrylate, ethyl (meth)acrylate, and glycidyl (meth)acrylate.

18. 18. The polypropylene graft containing anhydride groups according to claim 17, wherein the alkenyl-containing polymerizable monomer is selected from vinyl acetate, styrene, α-methylstyrene.

19. 1. A method for preparing an anhydride group-containing polypropylene graft for insulating materials, comprising: grafting a reaction mixture containing a polypropylene copolymer, an anhydride monomer, and an alkenyl-containing polymerizable monomer in the presence of an inert gas to obtain the anhydride group-containing polypropylene graft; The grafting reaction conditions are as follows: the content of structural units in the anhydride group-containing polypropylene graft, which are derived from the anhydride monomer and the alkenyl-containing polymerizable monomer and are in a grafted state, is 0.1 to 5 wt % relative to the weight of the anhydride group-containing polypropylene graft; and the molar ratio of structural units derived from the alkenyl-containing polymerizable monomer to structural units derived from the anhydride monomer in the anhydride group-containing polypropylene graft is 1:1 to 20; The polypropylene copolymer has at least one of the following characteristics: The comonomer content is 0.5 to 40 mol%; The content of xylene solubles is 2 to 80% by weight; The comonomer content in the xylene soluble matter is 10 to 70% by weight; the ratio of the intrinsic viscosity of the xylene soluble material to the polypropylene copolymer is 0.3 to 5; The alkenyl-containing polymerizable monomer is at least one selected from monomers having a structure represented by Formula 1, 【Chemistry 7】 In formula 1, R b , R c , and R d are each independently selected from H, substituted or unsubstituted alkyl; and R a is selected from substituted or unsubstituted alkyl, substituted or unsubstituted alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted ester group, substituted or unsubstituted carboxyl, substituted or unsubstituted cycloalkyl or heterocyclyl, and cyano.

20. the content of grafted structural units derived from the anhydride monomer and the alkenyl-containing polymerizable monomer in the anhydride group-containing polypropylene graft is 0.4 to 3 wt. % based on the weight of the anhydride group-containing polypropylene graft; and / or 20. The method of claim 19, wherein the molar ratio of structural units derived from the alkenyl-containing polymerizable monomer to structural units derived from the anhydride monomer in the anhydride group-containing polypropylene graft is 1:1-10.

21. 21. The method of claim 19 or 20, wherein the polypropylene copolymer has at least one of the following characteristics: the comonomer content is 0.5 to 30 mol%, or 4 to 25 wt%, or 4 to 22 wt%; the xylene solubles content is 18 to 75 wt%, or 30 to 70 wt%, or 30 to 67 wt%; the comonomer content in the xylene solubles is 10 to 50 wt %, or 20 to 35 wt %; The ratio of the intrinsic viscosity of the xylene soluble material to the polypropylene copolymer is 0.5 to 3, or 0.8 to 1.

3.

22. The method of any one of claims 19 to 21, wherein the polypropylene copolymer has at least one of the following characteristics: a melt flow rate under a load of 2.16 kg at 230°C of 0.01 to 60 g / 10 min, or 0.05 to 35 g / 10 min, or 0.5 to 15 g / 10 min; The melting point Tm is 100°C or higher, or 110 to 180°C, or 110 to 170°C, or 120 to 170°C, or 120 to 166°C; Weight average molecular weight is 20 x 10 ４ ~60 x 10 ４ g / mol.

23. The method according to any one of claims 19 to 22, wherein the content of structural units derived from the anhydride monomer and in a grafted state in the anhydride group-containing polypropylene graft is 0.05 to 2 wt%, or 0.2 to 0.7 wt%.

24. 24. The method of any one of claims 19 to 23, wherein the anhydride monomer is selected from anhydrides having at least one olefinic unsaturation.

25. the reaction mixture further comprises a free radical initiator; and / or the reaction mixture further comprises at least one of a dispersant, an interfacial agent, and an organic solvent; the mass content of the dispersant is 50 to 300% of the mass of the polypropylene copolymer; the mass content of the interfacial agent is 1 to 30% of the mass of the polypropylene copolymer; The method according to any one of claims 19 to 24, wherein the mass content of the organic solvent is 1 to 35% of the mass of the polypropylene copolymer.

26. the free radical initiator is selected from a peroxide-based free radical initiator and / or an azo-based free radical initiator; the peroxide-based free radical initiator is at least one selected from dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, lauroyl peroxide, dodecyl peroxide, tert-butylperoxybenzoic acid, diisopropyl peroxydicarbonate, tert-butylperoxy(2-ethylhexanoate), and dicyclohexyl peroxydicarbonate; 26. The method of claim 25, wherein the azo-based free radical initiator is azobisisobutyronitrile and / or azobisisoheptonitrile.

27. the ratio of the total weight of the anhydride monomer and the alkenyl-containing polymerizable monomer to the weight of the free radical initiator is 0.1 to 10:100, or 0.5 to 5:100; and / or 26. The method of claim 25, wherein the ratio of the weight of the polypropylene copolymer to the total weight of the anhydride monomer and the alkenyl-containing polymerizable monomer is 0.1 to 8:100, or 0.3 to 5:

100.

28. 28. The method of any one of claims 19 to 27, wherein the temperature of the grafting reaction is 30 to 130°C, or 60 to 120°C, and the time is 0.5 to 10 hours, or 1 to 5 hours.

29. The preparation method comprises the steps of: (a) placing the polypropylene copolymer in a sealed reactor and then replacing the atmosphere with an inert gas; (b) adding a free radical initiator, an anhydride monomer, and an alkenyl-containing polymerizable monomer to the closed reactor and mixing with stirring; (c) optionally adding an interfacial agent and optionally swelling the reaction system; (d) optionally adding a dispersant and heating the reaction system to a grafting reaction temperature to carry out the grafting reaction; (e) after completion of the reaction, optionally filtering and drying to obtain the anhydride group-containing polypropylene graft; or The preparation method comprises the steps of: (a) placing the polypropylene copolymer in a sealed reactor and then replacing the atmosphere with an inert gas; (b) mixing an organic solvent with a free radical initiator and adding the mixture to a closed reactor; (c) removing the organic solvent; (d) adding an anhydride monomer and an alkenyl-containing polymerizable monomer, optionally adding an interfacial agent, and optionally swelling the reaction system; (e) optionally adding a dispersant and heating the reaction system to a grafting reaction temperature to carry out the grafting reaction; (f) after completion of the reaction, optionally filtering and drying to obtain the anhydride group-containing polypropylene graft; The method according to any one of claims 19 to 28.

30. the alkenyl-containing polymerizable monomer is at least one selected from vinyl acetate, styrene, α-methylstyrene, (meth)acrylate, vinyl alkyl ether, vinylpyrrolidone, vinylpyridine, vinylimidazole, and acrylonitrile; 20. The method of claim 19, wherein the (meth)acrylate is at least one selected from methyl (meth)acrylate, ethyl (meth)acrylate, and glycidyl (meth)acrylate.

31. Use of the anhydride group-containing polypropylene graft according to any one of claims 1 to 18 as an insulating material.

32. The anhydride group-containing polypropylene graft for insulating material according to any one of claims 1 to 18, or the use according to claim 31, wherein the insulating material is a cable insulating material.

33. The anhydride group-containing polypropylene graft for insulating material according to any one of claims 1 to 18, or the use according to claim 31, wherein the insulating material is a direct current cable insulating material.

34. The anhydride group-containing polypropylene graft for insulating material according to any one of claims 1 to 18, or the use according to claim 31, wherein the insulating material is a cable insulating layer material.

35. at least one conductor and at least one electrically insulating layer surrounding the conductor; Cable, wherein the material of said electrical insulating layer is at least one polypropylene graft containing anhydride groups according to any one of claims 1 to 18.

36. the cable having at least one cable core; Each cable core includes, from the inside to the outside, a conductor, an optional conductor shielding layer, an electrically insulating layer, an optional electrically insulating shielding layer, and an optional metallic shielding layer; 36. The cable of claim 35, optionally the cable further comprising an armor and / or sheath layer and / or a filling layer and / or a wrapping layer.

37. 36. The cable of claim 35, wherein the cable is a DC cable or an AC cable.

38. An insulating material comprising at least one anhydride group-containing polypropylene graft according to any one of claims 1 to 18.

39. 39. The insulating material of claim 38, wherein the content of the at least one anhydride group-containing polypropylene graft is 20 to 100 wt. %, or 40 to 100 wt. %, or 60 to 100 wt. %, or 80 to 100 wt. %, or 90 to 100 wt. %, based on the weight of the insulating material.

40. 40. The insulating material of claim 38 or 39, further comprising one or more selected from antioxidants, stabilizers, processing aids, flame retardants, water tree retarding additives, acid or ion scavengers, inorganic fillers, voltage stabilizers, and copper inhibitors.

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