Compositions for the preparation of thermoplastic elastomers and thermoplastic elastomers and processes for their preparation and use

Abstract

The present application relates to the field of elastomer material, in particular to a kind of preparation thermoplastic elastomer composition and thermoplastic elastomer and its preparation method and application.The composition includes: ternary ethylene-propylene rubber 100 parts by weight, natural rubber 10-100 parts by weight, polypropylene 40-200 parts by weight, vulcanizing agent 1-10 parts by weight and antioxidant 0.1-5 parts by weight, wherein the Mooney viscosity of the natural rubber is 30-120.The thermoplastic elastomer prepared by the composition of the present application has good wear resistance and mechanical properties, low cost and easy processing.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of elastomer materials, in particular to a composition for preparing thermoplastic elastomer and thermoplastic elastomer and a preparation method and application thereof. BACKGROUND

[0002] Thermoplastic vulcanizate (TPV) refers to a thermoplastic elastomer prepared by using dynamic vulcanization technology. Dynamic vulcanization refers to that under the action of a crosslinking agent, the rubber is vulcanized and dispersed into the plastic continuous phase at the same time under the conditions of high temperature and high shear, and finally micron-sized vulcanized rubber phases are formed in the continuous phase of the plastic. TPV successfully combines some properties of vulcanized rubber, such as heat resistance and low compression deformation, with the easy processing properties of thermoplastic plastic, and is green and environmentally friendly, can be recycled and used, and has a wide range of applications.

[0003] The main application field of TPV at present is automobile parts, accounting for more than 60% of the total market share. In addition, it is also widely used in the fields of fluid treatment, medical materials, wires and cables, and building. The TPV product using ethylene-propylene-diene rubber as raw material is the TPV product with the largest use amount and the highest market share at present, but its wear resistance is poor, and the cost is high, and the price advantage is not obvious. Natural rubber has large elasticity, high modulus, excellent tear resistance and electrical insulation, good wear resistance and drought resistance, good processability, and easy adhesion to other materials, and its comprehensive performance is better than that of most synthetic rubbers. SUMMARY

[0004] The purpose of the present application is to overcome the problems of poor wear resistance and mechanical properties and high cost of the existing thermoplastic elastomer preparation technology, and to provide a composition for preparing thermoplastic elastomer and thermoplastic elastomer and a preparation method and application thereof. The thermoplastic elastomer prepared by the composition has the characteristics of good wear resistance and mechanical properties and low cost.

[0005] In order to achieve the above-mentioned purpose, the first aspect of the present application provides a composition for preparing thermoplastic elastomer, which comprises: 100 parts by weight of ethylene-propylene-diene rubber, 10-100 parts by weight of natural rubber, 40-200 parts by weight of polypropylene, 1-10 parts by weight of vulcanizing agent and 0.1-5 parts by weight of antioxidant, wherein,

[0006] The natural rubber has a Mooney viscosity of 30-120.

[0007] The second aspect of the present application provides a thermoplastic elastomer, which is prepared by melt processing the composition provided in the first aspect of the present application.

[0008] The third aspect of the present application provides a preparation method of thermoplastic elastomer, which comprises:

[0009] (1) first blending polypropylene and antioxidant, second blending the obtained melt with ethylene-propylene-diene rubber and natural rubber to obtain a mixing material by melting;

[0010] (2) extruding and granulating the mixing material to obtain mixing material granules;

[0011] (3) mixing the mixing material granules and vulcanizing agent to obtain a thermoplastic elastomer by dynamic vulcanization.

[0012] The fourth aspect of the present application provides application of the thermoplastic elastomer prepared by the preparation method of the second aspect or the third aspect of the present application in the field of automotive interior and exterior decoration and rail transit.

[0013] Through the above technical solution, the present application has the following advantages:

[0014] The thermoplastic elastomer prepared from the composition of the present application has good wear resistance and mechanical properties, low cost and easy processing.

[0015] The preparation method of the thermoplastic elastomer of the present application adopts a step-by-step blending melting and dynamic vulcanization processing method, and the prepared thermoplastic elastomer has good wear resistance and mechanical properties, and has the advantages of simple process operation, easy control of production conditions, less waste, energy saving, high production rate and the like. DETAILED DESCRIPTION

[0016] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The endpoints of the ranges of values and the values thereof can be combined with one another even if not stated explicitly to form one or more new ranges and / or values.

[0017] The present application provides a composition for preparing a thermoplastic elastomer, the composition comprising: 100 parts by weight of ethylene-propylene-diene rubber, 10-100 parts by weight of natural rubber, 40-200 parts by weight of polypropylene, 1-10 parts by weight of vulcanizing agent and 0.1-5 parts by weight of antioxidant, wherein,

[0018] The natural rubber has a Mooney viscosity of 30-120.

[0019] In the present application, the Mooney viscosity of the natural rubber is measured under the condition of ML125℃ 1+4.

[0020] The thermoplastic elastomer prepared from the composition of the present application has good wear resistance and mechanical properties, low cost and easy processing.

[0021] In the present application, the Mooney viscosity of the EPDM rubber is not particularly limited as long as the object of the present application can be achieved, and according to one preferred embodiment of the present application, the Mooney viscosity of the EPDM rubber is 40-90. By adopting the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared from the composition can be further improved.

[0022] In the present application, the Mooney viscosity of the EPDM rubber is measured under the condition of ML 125℃ 1+4.

[0023] According to one preferred embodiment of the present application, the content of the structural unit from the unsaturated third monomer in the EPDM rubber is 0.5-10wt%, and the content of the structural unit from ethylene is 50-75wt%, based on the total amount of the EPDM rubber. By adopting the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared from the composition can be further improved.

[0024] In the present application, the natural rubber can be a conventional selection in the art as long as the Mooney viscosity of the natural rubber is in the range of 30-120, and according to one preferred embodiment of the present application, the natural rubber is selected from at least one of pellet rubber, smoked sheet rubber, air-dried sheet rubber, crepe sheet rubber, and constant viscosity natural rubber, preferably Malaysian standard rubber. By adopting the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared from the composition can be further improved.

[0025] In the present application, the parameter condition of the polypropylene is not particularly limited as long as the object of the present application can be achieved, and according to one preferred embodiment of the present application, the number average molecular weight of the polypropylene is 200,000-900,000g / mol. By adopting the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared from the composition can be further improved.

[0026] In the present application, the vulcanizing agent can be a conventional selection in the art, and according to one preferred embodiment of the present application, the vulcanizing agent is an organic peroxide, preferably selected from at least one of dicumyl peroxide, bis(t-butylperoxy isopropyl) benzene, t-butyl cumyl peroxide, 2,5-bis(t-butylperoxy)-2,5-dimethyl-3-hexyne, 2,5-bis(t-butylperoxy)-2,5-dimethylhexane, dibenzoyl peroxide, t-butylperoxy benzoate, di-t-butyl peroxide, more preferably selected from dicumyl peroxide and / or bis(t-butylperoxy isopropyl) benzene. By adopting the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared from the composition can be further improved.

[0027] In the present application, the antioxidant can be a conventional selection in the art, according to one preferred embodiment of the present application, the antioxidant is a macromolecular multifunctional hindered phenolic antioxidant, preferably selected from at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester (antioxidant 1010), 2,6-di-tert-butyl-p-cresol (antioxidant 264), 2,2-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246) and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane. By adopting the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared from the composition can be further improved.

[0028] The present application provides a thermoplastic elastomer prepared from the composition by melt processing.

[0029] The thermoplastic elastomer has good wear resistance and mechanical properties, low cost and easy processing.

[0030] The present application provides a preparation method of a thermoplastic elastomer, which comprises:

[0031] (1) blending polypropylene and antioxidant to obtain a first blend, and then blending the obtained melt with ethylene-propylene-diene rubber and natural rubber to obtain a second blend, and then melting to obtain a mixing material; wherein the natural rubber has a Mooney viscosity of 30-120;

[0032] (2) extruding and granulating the mixing material to obtain mixing material particles;

[0033] (3) mixing the mixing material particles and a vulcanizing agent to perform dynamic vulcanization to obtain a thermoplastic elastomer.

[0034] The preparation method of the thermoplastic elastomer of the present application adopts a step-by-step blending and melting and dynamic vulcanization processing method, and the prepared thermoplastic elastomer has good wear resistance and mechanical properties, and has the advantages of simple process operation, easy control of production conditions, less scrap, energy saving, high production rate and the like.

[0035] In the present application, the blending equipment and corresponding operating conditions used in the first blending and the second blending in step (1) can be a conventional selection in the art, according to one preferred embodiment of the present application, in step (1), the blending equipment used in the first blending and the second blending includes an internal mixer, wherein the conditions of the first blending include: the rotor speed of the internal mixer is 60-90 rpm, and the blending temperature is 160-220°C; the conditions of the second blending include: the rotor speed of the internal mixer is 60-90 rpm, and the blending temperature is 160-220°C. By adopting the foregoing preferred scheme, the wear resistance and mechanical properties of the prepared thermoplastic elastomer can be further improved.

[0036] In the present application, the equipment used for the extrusion granulation in step (2) and the corresponding operating conditions can be the conventional selection in the art, according to one preferred embodiment of the present application, in step (2), the extrusion granulation is carried out by using a single screw extruder, wherein the conditions for the extrusion granulation include: the screw length-diameter ratio is 20-30, the screw rotation speed is 50-200 rpm, and the extrusion temperature is 160-220℃. By using the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared can be further improved.

[0037] In the present application, the equipment used for the dynamic vulcanization in step (3) and the corresponding operating conditions can be the conventional selection in the art, according to one preferred embodiment of the present application, in step (3), the dynamic vulcanization is carried out by using a co-rotating intermeshing twin-screw extruder, wherein the conditions for the dynamic vulcanization include: the screw length-diameter ratio is 44-65, the screw rotation speed is 50-300 rpm, the main feeding speed is 30-50 rpm, the die temperature is 170-200℃, the screw feeding section temperature is 120-170℃, and the screw melting and mixing section temperature is 180-220℃. By using the foregoing preferred scheme, the wear resistance and mechanical properties of the thermoplastic elastomer prepared can be further improved.

[0038] The present application provides an application of the thermoplastic elastomer in the field of automotive interior and exterior decoration and rail transportation.

[0039] The present application will be described in detail by way of examples. In the following examples, the raw materials used are all commercially available products, unless otherwise specified:

[0040] Ethylene-propylene-diene rubber: purchased from Shanghai Sinopec Mitsui Chemical Co., Ltd., with a brand name of 3092PM, a Mooney viscosity of 61, an ethylene- norbornene content of 4.6%, and an ethylene content of 65%;

[0041] Natural rubber: selected from Malaysia constant viscosity standard rubber SMR CV60 (ISNR-5), with a Mooney viscosity of 60±5;

[0042] Polypropylene: purchased from Sinopec Yangzi Petrochemical Co., Ltd., with a brand name of F401, a molecular weight of about 380-400 thousand, and a melt flow rate of 2.5 g / 10 min;

[0043] Antioxidant: antioxidant 1010, purchased from Shanghai Jinhaibaobao Fine Chemical Co., Ltd.; antioxidant 2246, purchased from Anhui Weichi Chemical Co., Ltd.; antioxidant 264, purchased from Wuxi Qianfeng Chemical Co., Ltd.;

[0044] Vulcanizing agent: dicumyl peroxide, purchased from Akzo Nobel China Co., Ltd., with a brand name of Luperox® 1010; BC-FF; Bis (tert-butylperoxy isopropyl) benzene, purchased from Hubei Ruixin Chemical Co., Ltd.

[0045] The properties involved are tested by the following methods:

[0046] (1) Hardness: tested according to standard GB / T 531.1-2008;

[0047] (2) Tensile strength: tested according to standard GB / T 528-2009;

[0048] (3) Elongation at break: tested according to standard GB / T 528-2009;

[0049] (4) Compression set: tested according to standard GB / T 7759-1996;

[0050] (5) Abrasion resistance test: tested according to WSK M98P5-A FLTM BN 108-02 standard, grinding wheel type: CS-10, load 500g, test speed 100, test time 2h.

[0051] Example 1

[0052] The preparation process of the thermoplastic elastomer is as follows:

[0053] (1) 100 parts by weight of polypropylene and 0.5 parts by weight of antioxidant 1010 were added to a Banbury mixer at 180°C, and after the polypropylene was melted, 100 parts by weight of ethylene-propylene-diene rubber and 100 parts by weight of natural rubber were added, and high-temperature melting was carried out to obtain a mixed material, the mixing conditions including: rotation speed 75 rpm, mixing temperature 180°C; the mixed material was subjected to first granulation by a single screw extruder, to obtain mixed material particles, the single screw extruder having a length-diameter ratio of 20:1, the first granulation conditions including: screw rotation speed 100 rpm, extrusion temperature 200°C;

[0054] (2) The mixed material particles prepared in step (1) were subjected to dynamic vulcanization and second granulation with 2 parts by weight of vulcanizing agent (dicumyl peroxide) in a co-rotating intermeshing twin-screw extruder to obtain thermoplastic vulcanized rubber particles, the co-rotating intermeshing twin-screw extruder having a length-diameter ratio of 44:1; the dynamic vulcanization conditions including: screw rotation speed 200 rpm, main feeding speed 40 rpm, die temperature 180°C, screw feeding section temperature 150°C, and melt mixing section temperature 180°C.

[0055] Examples 2-5

[0056] The same method as in Example 1 was used, except that the formulation or process parameters of the composition used were different, to produce thermoplastic elastomers, as shown in Table 1. In Example 3, the ethylene-propylene rubber was purchased from Shanghai Sinopec Mitsui Co., Ltd., with a brand name of 4045M, a Mooney viscosity of 45, an ethylene-ethylene content of 5%, and an ethylene content of 47%.

[0057] Table 1

[0058]

[0059] Examples 6-9

[0060] The same method as in Example 1 was used, except that the formulation or process parameters of the composition used were different, to produce thermoplastic elastomers, as shown in Table 1.

[0061] Table 1 (continued 1)

[0062]

[0063] Examples 10-13

[0064] The same method as in Example 1 was used, except that the formulation or process parameters of the composition used were different, to produce thermoplastic elastomers. In Example 13, a one-step method was used, in which the ethylene-propylene rubber particles, natural rubber particles, polypropylene particles, antioxidant, vulcanizing agent, and the like were mixed and then directly subjected to dynamic vulcanization using a twin-screw extruder to produce the thermoplastic elastomer, as shown in Table 1.

[0065] Table 1 (continued 2)

[0066]

[0067] Comparative Examples 1-4

[0068] The same method as in Example 1 was used, except that the formulation or process parameters of the composition used were different, to produce thermoplastic elastomers. In Comparative Example 1, the ethylene-propylene rubber was purchased from Dow Chemical Company, with a brand name of 3722P, a Mooney viscosity of 20, an ethylene-ethylene content of 0.5%, and an ethylene content of 70.5%, as shown in Table 1.

[0069] Table 1 (continued 3)

[0070]

[0071]

[0072] Test Example

[0073] The physical and mechanical properties of the thermoplastic elastomers prepared in the above examples were tested, and the specific results are shown in Table 2.

[0074] Table 2

[0075]

[0076] Table 2 (continued 1)

[0077]

[0078]

[0079] Table 2 (continued 2)

[0080]

[0081] Table 2 (continued 3)

[0082]

[0083] As can be seen from Table 1 and Table 2, the thermoplastic elastomers obtained by using the composition of the present application can obtain excellent physical and mechanical properties, for example, compared with Example 1 implemented according to the preferred scheme of the present application and Example 3 (the content of structural units from ethylene is not 50-75 wt%), Example 4 (the vulcanizing agent is dibenzoyl peroxide) and Example 13 (one-step mixing method) implemented according to the non-preferred scheme, the tensile strength is greater, the elongation at break is greater, the compression set is smaller, and the wear degree is also smaller. Compared with Comparative Examples 1-4 which do not use the technical scheme of the present application, the performance of the elastomers obtained by Examples 1-13 using the scheme of the present application is more obviously improved, and is particularly suitable for use in automotive interior and exterior, rail transit and other fields.

[0084] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical scheme of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for preparing a thermoplastic elastomer, characterized in that, The composition used for preparing thermoplastic elastomers is characterized in that, The composition comprises: 100 parts by weight of ethylene propylene diene monomer (EPDM) rubber, 10-100 parts by weight of natural rubber, 40-200 parts by weight of polypropylene, 1-10 parts by weight of vulcanizing agent, and 0.1-5 parts by weight of antioxidant, wherein... The Mooney viscosity of the natural rubber is 30-120; The Mooney viscosity of the EPDM rubber is 40-90; based on the total amount of the EPDM rubber, the content of structural units from the unsaturated third monomer in the EPDM rubber is 0.5-10 wt%, and the content of structural units from ethylene is 50-75 wt%. The vulcanizing agent is an organic peroxide; The antioxidant is a macromolecular multifunctional hindered phenolic antioxidant. The preparation method includes the following steps: (1) Polypropylene and antioxidant are first blended, and the resulting melt is second blended with EPDM rubber and natural rubber, and the mixture is melted to obtain a compound; wherein the Mooney viscosity of the natural rubber is 30-120. (2) The mixture is extruded and granulated to obtain mixture granules; (3) The compound particles and vulcanizing agent are mixed and dynamically vulcanized to obtain a thermoplastic elastomer.

2. The preparation method according to claim 1, wherein, The natural rubber is selected from at least one of granulated rubber, smoked sheet rubber, air-dried sheet rubber, crepe rubber, and constant tack natural rubber.

3. The preparation method according to claim 1, wherein, The natural rubber mentioned is constant tack natural rubber.

4. The preparation method according to claim 1, wherein, The natural rubber mentioned is Malaysian constant tack standard rubber.

5. The preparation method according to claim 1, wherein, The number-average molecular weight of the polypropylene is 20,000-900,000 g / mol.

6. The preparation method according to claim 1, wherein, The vulcanizing agent is selected from at least one of dicumyl peroxide, bis(tert-butylperoxide)benzene, tert-butylperoxide, 2,5-bis(tert-butylperoxide)-2,5-dimethyl-3-hexyne, 2,5-bis(tert-butylperoxide)-2,5-dimethylhexane, benzoyl peroxide, tert-butyl peroxide, and ditert-butyl peroxide; The antioxidant is selected from at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-p-cresol, 2,2-methylenebis(4-methyl-6-tert-butylphenol) and 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane.

7. The preparation method according to claim 1, wherein, The vulcanizing agent is selected from dicumyl peroxide and / or bis(tert-butylperoxide)benzene.

8. The preparation method according to claim 1, wherein, In step (1), the blending equipment used for the first blending and the second blending includes an internal mixer, wherein, The conditions for the first blending include: a mixer rotor speed of 60-90 rpm and a blending temperature of 160-220℃; and / or The conditions for the second blending include: the internal mixer rotor speed is 60-90 rpm and the blending temperature is 160-220℃.

9. The preparation method according to claim 1, wherein, In step (2), the extrusion granulation is performed using a single-screw extruder, wherein, The extrusion granulation conditions include: a screw length-to-diameter ratio of 20-30, a screw speed of 50-200 rpm, and an extrusion temperature of 160-220℃.

10. The preparation method according to any one of claims 1-9, wherein, In step (3), dynamic vulcanization is performed using a co-rotating twin-screw extruder, wherein, The conditions for dynamic vulcanization include: a screw length-to-diameter ratio of 44-65, a screw speed of 50-300 rpm, a main feed speed of 30-50 rpm, a die head temperature of 170-200℃, a screw feed section temperature of 120-170℃, and a screw melting and mixing section temperature of 180-220℃.

11. The application of the thermoplastic elastic material prepared by the preparation method according to any one of claims 1-10 in the fields of automotive interior and exterior trim and rail transportation.

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