A high melt strength polypropylene material and a method for its preparation, use

Abstract

The application provides a high-melt-strength polypropylene material and a preparation method and application thereof, the high-melt-strength polypropylene material is prepared by the following steps: melt grafting polypropylene, a polar monomer and a first initiator to obtain a polar grafted polypropylene; ion modifying the polar grafted polypropylene by a metal salt to obtain a polypropylene metal ionomer with a grafted structure; and crosslinking the polypropylene and the polypropylene metal ionomer to obtain the high-melt-strength polypropylene material. The high-melt-strength polypropylene material provided by the application can improve the melt strength of polypropylene, and meanwhile, the high-melt-strength polypropylene material has excellent performance and good mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a high melt strength polypropylene material and a preparation method and application thereof. BACKGROUND

[0002] As one of the most widely used general-purpose plastics, polypropylene has the advantages of high melting point, corrosion resistance, good electrical insulation, excellent mechanical properties, easy processing and low production cost, and is widely used in packaging materials, insulation materials, automobile industry, electronic communication and health care fields. However, most of the polypropylene materials currently used are linear structures with relatively narrow molecular weight distribution, resulting in a short melting range and a narrow processing window during processing. When the processing temperature is higher than the melting point of polypropylene, the melt strength and melt viscosity of polypropylene decrease sharply, which is difficult to meet the requirements of different forming processes. Especially in the foaming process, due to the small molecular weight and low melt strength of polypropylene, there is no strain hardening effect in the molten state, making it difficult for the gas to remain in the polypropylene melt, resulting in uneven cell size, cell collapse and low foaming ratio, and it is difficult to prepare high-quality foaming products.

[0003] High melt strength polypropylene is a kind of polypropylene material developed to overcome the defects of linear polypropylene in foaming process. By introducing long chain branches and widening the molecular weight distribution, the melt strength of polypropylene can be improved, and the strain hardening can be improved. However, the improvement of melt strength and mechanical properties is not ideal, and the mechanical properties of high melt strength polypropylene material are poor.

[0004] Therefore, there is an urgent need to develop a high melt strength polypropylene material with excellent mechanical properties. SUMMARY

[0005] The present application aims to provide a high melt strength polypropylene material and a preparation method and application thereof, to solve the technical problem of poor mechanical properties of high melt strength polypropylene material in the prior art.

[0006] To solve the above technical problems, the technical solutions of the present application are as follows:

[0007] A high melt strength polypropylene material is prepared by melt grafting polypropylene, polar monomer and first initiator to obtain polar grafted polypropylene; then ion modification is carried out on the polar grafted polypropylene with metal salt to obtain polypropylene metal ionomer with graft structure; and then crosslinking is carried out on the polypropylene and the polypropylene metal ionomer to obtain the high melt strength polypropylene material.

[0008] Preferably, the high melt strength polypropylene material has a crosslinked network structure, a melt index of 1-5 g / 10 min and a melt strength of 10-70 cN.

[0009] Preferably, the polypropylene is linear polypropylene with a melt index of 0.1-10 g / 10 min;

[0010] Optionally, the polar monomer is one or more of anhydride, acid, ester, amide;

[0011] Preferably, the polar monomer is one or more of an unsaturated bond-containing anhydride, acid, ester, amide.

[0012] Optionally, the first initiator is one or more of benzoyl peroxide, lauryl peroxide, dicumyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide.

[0013] Preferably, the polar grafted polypropylene is prepared from the following raw materials by weight:

[0014] 100 parts of polypropylene, 1-10 parts of polar monomer, 0.1-0.5 parts of first initiator.

[0015] Preferably, the preparation raw materials of the polar grafted polypropylene further comprise 0.1-1 parts of first antioxidant;

[0016] Optionally, the first antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 626.

[0017] Preferably, the metal salt is one or more of metal zinc salt, metal sodium salt, metal nickel salt, and hydrates thereof.

[0018] Preferably, the polypropylene metal ionomer is prepared from the following raw materials by weight:

[0019] 100 parts of polar grafted polypropylene, 5-20 parts of metal salt.

[0020] Preferably, the preparation raw materials of the high melt strength polypropylene material comprise: polypropylene, the polypropylene metal ionomer, nucleating agent, second initiator, second antioxidant;

[0021] Optionally, the nucleating agent is one or more of talc, nano calcium carbonate;

[0022] Optionally, the second initiator is one or more of benzoyl peroxide, lauryl peroxide, dicumyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide.

[0023] Optionally, the second antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, and antioxidant 626.

[0024] Preferably, the high melt strength polypropylene material is prepared by the following raw materials in parts by weight:

[0025] Polypropylene 100 parts, polypropylene metal ionomer 5-20 parts, nucleating agent 0.1-3 parts, second initiator 0.05-0.1 parts, second antioxidant 0.1-0.5.

[0026] Preferably, the polypropylene is linear polypropylene.

[0027] The application also provides a preparation method of the high melt strength polypropylene material, comprising the following steps:

[0028] (1) taking polypropylene, polar monomer and first initiator to carry out melt reaction to obtain polar grafted polypropylene;

[0029] (2) taking metal salt and the polar grafted polypropylene in step (1) to carry out melt modification to obtain polypropylene metal ionomer with grafted structure;

[0030] (3) taking polypropylene and the polypropylene metal ionomer in step (2) to carry out crosslinking reaction to obtain high melt strength polypropylene material.

[0031] Preferably, the preparation method of the high melt strength polypropylene material comprises the following steps:

[0032] (1) taking polypropylene, polar monomer and first initiator, mixing uniformly, and carrying out melt extrusion reaction through a double-screw extruder to obtain polar grafted polypropylene; wherein the extrusion temperature of the double-screw extruder is 170-200 DEG C, and the screw rotation speed is 100-200 rpm;

[0033] (2) taking metal salt and the polar grafted polypropylene in step (1), carrying out melt extrusion blending modification through a double-screw extruder to obtain polypropylene metal ionomer with grafted structure; wherein the extrusion temperature of the double-screw extruder is 180-220 DEG C, and the screw rotation speed is 100-200 rpm;

[0034] (3) taking polypropylene and the polypropylene metal ionomer in step (2), carrying out melt extrusion crosslinking reaction through a double-screw extruder or a triple-screw extruder to obtain high melt strength polypropylene material; wherein the extrusion temperature of the double-screw extruder or the triple-screw extruder is 200-260 DEG C, and the screw rotation speed is 100-300 rpm.

[0035] The application also provides application of the high melt strength polypropylene material in the field of foaming materials.

[0036] The above scheme of the application at least has the following beneficial effects:

[0037] (1) The high melt strength polypropylene material of the present application is prepared by melt grafting polypropylene, polar monomer and first initiator to obtain polar grafted polypropylene; then ion modifying the polar grafted polypropylene with metal salt to obtain polypropylene metal ionomer with grafted structure; and then crosslinking polypropylene and the polypropylene metal ionomer to obtain the high melt strength polypropylene material. The high melt strength polypropylene material of the present application is prepared by melt grafting polypropylene, polar monomer and first initiator to obtain polar grafted polypropylene with short branch and high grafting rate, which solves the problem of difficult preparation of polypropylene with high grafting rate. Then, without adding other additives, the polar grafted polypropylene is ion modified by metal salt through the interaction between metal ions to obtain the polypropylene metal ionomer. Finally, under the synergistic effect of physical entanglement of the polypropylene metal ionomer and polypropylene molecular chain and chemical crosslinking between polypropylene molecular chains, the high melt strength polypropylene with adjustable network structure is obtained to improve the defects of small molecular weight of polypropylene ionomer and low melt strength of polypropylene, and the melt strength of polypropylene is improved. At the same time, the high melt strength polypropylene material obtained has excellent performance and good mechanical properties.

[0038] (2) The raw materials for preparing the high melt strength polypropylene material of the present application include polypropylene, the polypropylene metal ionomer, nucleating agent, second initiator and second antioxidant. The introduction of metal ions of the polypropylene metal ionomer and nucleating agent can better control the crystallization and foaming nucleation of polypropylene, improve its foaming performance, and thus be better used in foaming materials.

[0039] (3) The preparation method of the high melt strength polypropylene material of the present application is simple in process, high in production efficiency and low in cost, and is suitable for use in foaming materials. DETAILED DESCRIPTION

[0040] Unless otherwise indicated, the conditions in the various embodiments of the present application are carried out under conventional conditions or the conditions recommended by the manufacturer. Unless otherwise indicated, the reagents or instruments used are conventional products that can be obtained commercially, and the use of raw materials of different manufacturers and models does not affect the implementation of the technical solutions of the present application and the realization of the technical effects.

[0041] Example 1

[0042] The high melt strength polypropylene material of the present embodiment is prepared by melt grafting polypropylene, polar monomer and first initiator to obtain polar grafted polypropylene; then ion modifying the polar grafted polypropylene with metal salt to obtain polypropylene metal ionomer with grafted structure; and then crosslinking polypropylene and the polypropylene metal ionomer to obtain the high melt strength polypropylene material.

[0043] The polar grafting polypropylene is prepared by the following raw materials in weight parts:

[0044] Polypropylene 100 parts, polar monomer 10 parts, first initiator 0.3 parts, first antioxidant 0.1 part. Among them, the polypropylene for preparing the polar grafting polypropylene is linear polypropylene with a melt index of 0.1 g / 10 min, which can be homo-polypropylene or copolymer polypropylene; the polar monomer is an acid anhydride; in this embodiment, it is maleic anhydride. The first initiator is benzoyl peroxide. The first antioxidant is antioxidant 1010, with a CAS number of 6683-19-8.

[0045] The polypropylene metal ionomer is prepared by the following raw materials in weight parts:

[0046] The polar grafting polypropylene 100 parts, metal salt 5 parts. Among them, the metal salt is zinc stearate.

[0047] The high melt strength polypropylene material is prepared by the following raw materials in weight parts:

[0048] Polypropylene 100 parts, polypropylene metal ionomer 20 parts, nucleating agent 1.5 parts, second initiator 0.1 part, second antioxidant 0.1. Among them, the nucleating agent is a mixture of talc and nano calcium carbonate in a weight ratio of 1:1; the second initiator is benzoyl peroxide; the second antioxidant is antioxidant 1076, with a CAS number of 2082-79-3.

[0049] The preparation method of the high melt strength polypropylene material in this embodiment includes the following steps:

[0050] (1) Take polypropylene, polar monomer and first initiator, mix uniformly, and carry out melt extrusion reaction through a double-screw extruder to obtain a polar grafting polypropylene; wherein the extrusion temperature of the double-screw extruder is 170°C, and the screw rotation speed is 150 rpm;

[0051] (2) Take metal salt and the polar grafting polypropylene in step (1), and carry out melt extrusion blending modification through a double-screw extruder to obtain a polypropylene metal ionomer with grafting structure; wherein the extrusion temperature of the double-screw extruder is 180°C, and the screw rotation speed is 200 rpm;

[0052] (3) Take polypropylene and the polypropylene metal ionomer in step (2), and carry out melt extrusion crosslinking reaction through a double-screw extruder or a triple-screw extruder to obtain a high melt strength polypropylene material; wherein the extrusion temperature of the double-screw extruder or the triple-screw extruder is 230°C, and the screw rotation speed is 100 rpm.

[0053] The high melt strength polypropylene material obtained in the embodiment can be used for preparing foamed materials.

[0054] Embodiment 2

[0055] The high melt strength polypropylene material of the embodiment is prepared by melt grafting polypropylene, a polar monomer and a first initiator to obtain a polar grafted polypropylene; then ionically modifying the polar grafted polypropylene with a metal salt to obtain a polypropylene metal ionomer with a grafted structure; and then crosslinking the polypropylene with the polypropylene metal ionomer to obtain the high melt strength polypropylene material.

[0056] The polar grafted polypropylene is prepared from the following raw materials by weight:

[0057] The polypropylene is 100 parts, the polar monomer is 1 part, the first initiator is 0.5 part, and the first antioxidant is 1 part. The polypropylene used for preparing the polar grafted polypropylene is linear polypropylene with a melt index of 10 g / 10 min, which can be homopolymer polypropylene or copolymer polypropylene; the polar monomer is an acid, which is acrylic acid in the embodiment; and the first initiator is lauryl peroxide. The first antioxidant is antioxidant 168, which has a CAS number of 31570-04-4.

[0058] The polypropylene metal ionomer is prepared from the following raw materials by weight:

[0059] The polar grafted polypropylene is 100 parts, and the metal salt is 20 parts. The metal salt is sodium propionate.

[0060] The high melt strength polypropylene material is prepared from the following raw materials by weight:

[0061] The polypropylene is 100 parts, the polypropylene metal ionomer is 5 parts, the nucleating agent is 0.1 part, the second initiator is 0.08 part, and the second antioxidant is 0.5 part. The nucleating agent is nano calcium carbonate; the second initiator is lauryl peroxide; and the second antioxidant is antioxidant 626, which is bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite.

[0062] The preparation method of the high melt strength polypropylene material of the embodiment includes the following steps:

[0063] (1) Take polypropylene, a polar monomer and a first initiator, mix them uniformly, and perform melt extrusion reaction through a double-screw extruder to obtain a polar grafted polypropylene; wherein the extrusion temperature of the double-screw extruder is 185℃, and the screw rotation speed is 200 rpm.

[0064] (2) taking the metal salt and the polar grafting polypropylene in step (1) to perform melt extrusion blending modification through a double-screw extruder to obtain a polypropylene metal ionomer with a graft structure; wherein the extrusion temperature of the double-screw extruder is 220℃, and the screw rotation speed is 150 rpm;

[0065] (3) taking the polypropylene and the polypropylene metal ionomer in step (2) to perform melt extrusion crosslinking reaction through a double-screw extruder or a triple-screw extruder to obtain a high-melt-strength polypropylene material; wherein the extrusion temperature of the double-screw extruder or the triple-screw extruder is 260℃, and the screw rotation speed is 300 rpm.

[0066] The high-melt-strength polypropylene material obtained in the embodiment can be used for the preparation of a foaming material.

[0067] Embodiment 3

[0068] The high-melt-strength polypropylene material of the embodiment is prepared by melt grafting of polypropylene, a polar monomer and a first initiator to obtain a polar grafting polypropylene, then ion modification of a metal salt and the polar grafting polypropylene to obtain a polypropylene metal ionomer with a graft structure, and then crosslinking of polypropylene and the polypropylene metal ionomer to obtain a high-melt-strength polypropylene material.

[0069] The polar grafting polypropylene is prepared from the following raw materials by weight:

[0070] Polypropylene 100 parts, polar monomer 5 parts, first initiator 0.1 part, first antioxidant 0.5 part. Among them, the polypropylene for preparing the polar grafting polypropylene is linear polypropylene with a melt index of 5 g / 10 min, which can be homopolymer polypropylene or copolymer polypropylene; the polar monomer is an ester, which is methyl methacrylate in the embodiment; the first initiator is dicumyl peroxide. The first antioxidant is antioxidant 1076.

[0071] The polypropylene metal ionomer is prepared from the following raw materials by weight:

[0072] The polar grafting polypropylene 100 parts, the metal salt 12 parts. Among them, the metal salt is nickel benzoate.

[0073] The high-melt-strength polypropylene material is prepared from the following raw materials by weight:

[0074] Polypropylene 100 parts, polypropylene metal ionomer 12 parts, nucleating agent 3 parts, second initiator 0.05 part, second antioxidant 0.3. Among them, the nucleating agent is talc; the second initiator is dicumyl peroxide; and the second antioxidant is antioxidant 1010.

[0075] The preparation method of the high melt strength polypropylene material described in the embodiment comprises the following steps:

[0076] (1) Take polypropylene, polar monomer and first initiator, mix uniformly, and perform melt extrusion reaction through a double-screw extruder to obtain polar grafted polypropylene; wherein the extrusion temperature of the double-screw extruder is 200°C, and the screw rotation speed is 100 rpm;

[0077] (2) Take metal salt and the polar grafted polypropylene in step (1), perform melt extrusion blending modification through a double-screw extruder to obtain polypropylene metal ionomer with grafted structure; wherein the extrusion temperature of the double-screw extruder is 200°C, and the screw rotation speed is 100 rpm;

[0078] (3) Take polypropylene and the polypropylene metal ionomer in step (2), perform melt extrusion crosslinking reaction through a double-screw extruder or a triple-screw extruder to obtain high melt strength polypropylene material; wherein the extrusion temperature of the double-screw extruder or the triple-screw extruder is 200°C, and the screw rotation speed is 200 rpm.

[0079] The high melt strength polypropylene material obtained in the embodiment can be used for the preparation of foaming material.

[0080] Embodiment 4

[0081] The high melt strength polypropylene material of the embodiment is prepared by melt grafting of polypropylene, polar monomer and first initiator to obtain polar grafted polypropylene, then ion modification of metal salt and the polar grafted polypropylene to obtain polypropylene metal ionomer with grafted structure, and then crosslinking of polypropylene and the polypropylene metal ionomer to obtain high melt strength polypropylene material.

[0082] The polar grafted polypropylene is prepared from the following raw materials by weight:

[0083] Polypropylene 100 parts, polar monomer 5 parts, first initiator 0.3 parts, and first antioxidant 0.5 parts. Among them, the polypropylene for preparing the polar grafted polypropylene is linear polypropylene with a melt index of 5 g / 10 min; the polar monomer is amide, which is acrylamide in the embodiment; the first initiator is tert-butyl peroxybenzoate. The first antioxidant is antioxidant 626.

[0084] The polypropylene metal ionomer is prepared from the following raw materials by weight:

[0085] The polar grafted polypropylene 100 parts, metal salt 10 parts. Among them, the metal salt is nickel chloride hexahydrate.

[0086] The high melt strength polypropylene material is prepared by the following raw materials by weight:

[0087] Polypropylene 100 parts, polypropylene metal ionomer 12 parts, nucleating agent 1.5 parts, second initiator 0.07 parts, second antioxidant 0.3. Among them, the nucleating agent is talc; the second initiator is tert-butyl hydroperoxide; the second antioxidant is antioxidant 1076.

[0088] The preparation method of the high melt strength polypropylene material described in this embodiment includes the following steps:

[0089] (1) Take polypropylene, polar monomer and first initiator, mix uniformly, and carry out melt extrusion reaction through a double screw extruder to obtain a polar grafted polypropylene; wherein the extrusion temperature of the double screw extruder is 180℃, and the screw rotation speed is 150rpm;

[0090] (2) Take the metal salt and the polar grafted polypropylene in step (1), and carry out melt extrusion blending modification through a double screw extruder to obtain a polypropylene metal ionomer with a graft structure; wherein the extrusion temperature of the double screw extruder is 200℃, and the screw rotation speed is 150rpm;

[0091] (3) Take polypropylene and the polypropylene metal ionomer in step (2), and carry out melt extrusion crosslinking reaction through a double screw extruder or a triple screw extruder to obtain a high melt strength polypropylene material; wherein the extrusion temperature of the double screw extruder or the triple screw extruder is 230℃, and the screw rotation speed is 200rpm.

[0092] The high melt strength polypropylene material obtained in this embodiment can be used for the preparation of foaming materials.

[0093] Example 5

[0094] The raw materials of the high melt strength polypropylene material in this embodiment and example 4 are the same, and the same method is used for preparation, the only difference is that the polar monomer is fumaric acid.

[0095] Example 6

[0096] The raw materials of the high melt strength polypropylene material in this embodiment and example 4 are the same, and the same method is used for preparation, the only difference is that the polar monomer is butyl acrylate.

[0097] Example 7

[0098] The raw materials of the high melt strength polypropylene material in this embodiment and example 4 are the same, and the same method is used for preparation, the only difference is that the metal salt is sodium phosphate.

[0099] Example 8

[0100] The raw materials of the high melt strength polypropylene material of the present example are the same as those of Example 4, and the preparation is carried out by the same method, with the only difference being that the metal salt is magnesium stearate.

[0101] Example 9

[0102] The raw materials of the high melt strength polypropylene material of the present example are the same as those of Example 4, and the preparation is carried out by the same method, with the only difference being that the metal salt is magnesium stearate, and the polar monomer is fumaric acid.

[0103] Comparative Example 1

[0104] The high melt strength polypropylene material of the present comparative example is prepared by the following method:

[0105] Take 100 parts of polypropylene, 2 parts of styrene monomer, 0.2 parts of the first initiator, and 0.2 parts of the first antioxidant, mix them uniformly, and then add them into a twin-screw extruder for melt reaction extrusion. The extrusion temperature of the twin-screw extruder is set to 200℃, and the screw rotation speed is 150rpm. The long-chain branched polypropylene is obtained.

[0106] The first initiator and the first antioxidant are the same as those of Example 4.

[0107] Effect Comparative Example

[0108] In order to verify the technical effect of the high melt strength polypropylene material of the present application, the following tests are carried out:

[0109] Take the high melt strength polypropylene materials prepared in Examples 1-8 and Comparative Example 1, and the polypropylene in step (1) of Example 4, respectively, and measure the melt strength by using a melt strength tester, test the melt index by using the American Measurement Standard Association (ASTM) method, test the tensile strength according to the method of GB / T 2412-2008, test the bending modulus according to the method of GB / T 9341-2008, and test the notched impact strength according to the method of GB / T 1843-2008. According to the extrusion foaming ratio, test the foaming performance of the material, and according to the elution monomer method, titrate and calculate the grafting rate of the high melt strength polypropylene material.

[0110] After the experiment, the results are as follows:

[0111]

[0112]

[0113] From the above results, compared with the comparative example 1, the melt strength of the material prepared by the application is obviously improved, and the tensile strength, notched impact strength and bending modulus are also improved to a certain extent, and the foaming performance is also outstanding. It can be seen that the high melt strength polypropylene material has higher melt strength, better mechanical properties and better foaming performance.

[0114] From the technical common sense, the application can be realized by other embodiments without departing from the spirit or essential characteristics thereof. Therefore, the above disclosed embodiments are only examples in all aspects, and are not the only ones. All changes within the scope of the application or within the scope equivalent to the application are included in the application.

Claims

1. A high melt strength polypropylene material, characterized in that, The polar grafting polypropylene is prepared by melt grafting polypropylene, polar monomer and first initiator; the polypropylene metal ionomer with graft structure is obtained by ion modification of the polar grafting polypropylene with metal salt; and the high melt strength polypropylene material is obtained by crosslinking polypropylene with the polypropylene metal ionomer; The polypropylene metal ionomer is prepared by the following raw materials by weight: 100 parts of the polar grafting polypropylene and 10-20 parts of metal salt; The metal salt is one or more of metal zinc salt, metal sodium salt, metal nickel salt and hydrates thereof.

2. The high melt strength polypropylene material according to claim 1, characterized in that, The polypropylene is linear polypropylene with melt index of 0.1-10 g / 10 min. Optionally, the polar monomer is one or more of acid anhydride, acid, ester and amide. Optionally, the first initiator is one or more of benzoyl peroxide, lauryl peroxide, dicumyl peroxide, tert-butyl benzoyl peroxide and tert-butyl hydroperoxide.

3. The high melt strength polypropylene material according to claim 1, characterized in that, The polar grafting polypropylene is prepared by the following raw materials by weight: 100 parts of polypropylene, 1-10 parts of polar monomer and 0.1-0.5 parts of first initiator.

4. The high melt strength polypropylene material according to claim 3, characterized in that, The raw materials for preparing the polar grafting polypropylene further include 0.1-1 parts of first antioxidant. Optionally, the first antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 1076 and antioxidant 626.

5. The high melt strength polypropylene material according to claim 1, characterized in that, The raw materials for preparing the high melt strength polypropylene material include polypropylene, the polypropylene metal ionomer, nucleating agent, second initiator and second antioxidant. Optionally, the nucleating agent is one or more of talc and nano calcium carbonate. Optionally, the second initiator is one or more of benzoyl peroxide, lauryl peroxide, dicumyl peroxide, tert-butyl benzoyl peroxide and tert-butyl hydroperoxide. Optionally, the second antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 1076 and antioxidant 626.

6. The high melt strength polypropylene material according to claim 5, characterized in that, The high melt strength polypropylene material is prepared by the following raw materials by weight: 100 parts of polypropylene, 5-20 parts of polypropylene metal ionomer, 0.1-3 parts of nucleating agent, 0.05-0.1 parts of second initiator and 0.1-0.5 parts of second antioxidant.

7. A process for the preparation of a high melt strength polypropylene material according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: (1) melt reaction of polypropylene, polar monomer and first initiator to obtain polar grafting polypropylene; (2) melt modification of metal salt with the polar grafting polypropylene in step (1) to obtain polypropylene metal ionomer with graft structure; (3) crosslinking reaction of polypropylene with the polypropylene metal ionomer in step (2) to obtain high melt strength polypropylene material.

8. Use of the high melt strength polypropylene material according to any one of claims 1-7 in the field of foaming materials.

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