阅读说明：本技术 耐低温低硬度热塑性弹性体及其制备方法 (Low-temperature-resistant low-hardness thermoplastic elastomer and preparation method thereof ) 是由 王晓敏 刘浩 刘容德 王晶 张新华 孙丽朋 王秀丽 高磊 于 2020-06-24 设计创作，主要内容包括：本发明涉及一种耐低温低硬度热塑性弹性体及其制备方法,属于高分子弹性体领域。所述的耐低温低硬度热塑性弹性体,由如下质量份数的原料制成：聚丙烯树脂10-40份；含碳纳米管的粉末丁苯橡胶60-90份；聚异丁烯5-20份；硫化剂1-5份；促进剂0.1-1份。本发明以丁苯橡胶和聚丙烯树脂为基本原料采用动态硫化技术,用碳纳米管乳液与丁苯橡胶乳液共絮凝工艺制备含碳纳米管的粉末丁苯橡胶,与聚丙烯树脂共混以低分子量聚异丁烯充油软化制备耐低温低硬度热塑性弹性体。用碳纳米管乳液与丁苯橡胶乳液共絮凝工艺解决了填料分散性差导致的永久变形大的问题,填充低分子量聚异丁烯降低了TPV制品的硬度,TPV耐低温性能优异。(The invention relates to a low-temperature-resistant low-hardness thermoplastic elastomer and a preparation method thereof, belonging to the field of high-molecular elastomers. The low-temperature-resistant low-hardness thermoplastic elastomer is prepared from the following raw materials in parts by mass: 10-40 parts of polypropylene resin; 60-90 parts of powdered styrene butadiene rubber containing carbon nano tubes; 5-20 parts of polyisobutylene; 1-5 parts of a vulcanizing agent; 0.1-1 part of accelerator. The invention uses butadiene styrene rubber and polypropylene resin as basic raw materials, adopts dynamic vulcanization technology, uses the co-flocculation process of carbon nanotube emulsion and butadiene styrene rubber emulsion to prepare powdered butadiene styrene rubber containing carbon nanotubes, and mixes the powdered butadiene styrene rubber with polypropylene resin to prepare the low-temperature resistant low-hardness thermoplastic elastomer by oil-filling and softening of low-molecular-weight polyisobutylene. The co-flocculation process of the carbon nanotube emulsion and the styrene-butadiene rubber emulsion solves the problem of large permanent deformation caused by poor filler dispersibility, the filling of the low molecular weight polyisobutylene reduces the hardness of the TPV product, and the TPV has excellent low temperature resistance.)

1. A low temperature resistant low hardness thermoplastic elastomer characterized by: the feed is prepared from the following raw materials in parts by mass:

2. the low temperature resistant low hardness thermoplastic elastomer according to claim 1, characterized in that: the polyisobutylene is low-molecular-weight polyisobutylene, and the molecular weight range is 700-1000.

3. The low temperature resistant low hardness thermoplastic elastomer according to claim 1, characterized in that: the mass content of the carbon nano tubes in the styrene butadiene rubber containing the carbon nano tubes is 15-20%.

4. The low temperature resistant low hardness thermoplastic elastomer according to claim 1, characterized in that: the preparation method of the powdered styrene-butadiene rubber containing the carbon nano tubes comprises the following steps:

adding deionized water into a coagulator, controlling the temperature at 60-70 ℃, adding 18-22% sodium chloride solution into the coagulator, starting stirring at the stirring speed of 300-.

5. The low temperature resistant low hardness thermoplastic elastomer according to claim 4, characterized in that: the carbon nano tube aqueous solution contains modified carbon nano tubes.

6. The low temperature resistant low hardness thermoplastic elastomer according to claim 5, characterized in that: the modified carbon nano tube is a carboxyl modified carbon nano tube.

7. The low temperature resistant low hardness thermoplastic elastomer according to claim 1, characterized in that: the vulcanizing agent is 2, 5-dimethyl-2, 5-di-tert-butyl hexane peroxide.

8. The low temperature resistant low hardness thermoplastic elastomer according to claim 1, characterized in that: the accelerant is triacrylate isocyanurate.

9. A method for preparing a low temperature resistant low hardness thermoplastic elastomer according to any one of claims 1 to 8, characterized in that: the method comprises the following steps:

the preparation method comprises the steps of refining powdered styrene butadiene rubber containing carbon nano tubes, polypropylene resin, polyisobutylene, a vulcanizing agent and an accelerator in an internal mixer to prepare a premix, adding the premix into a double-screw extruder for reaction and extrusion, granulating, and extruding TPV sheets from granules on a Brabender single-screw extruder unit.

10. The method for preparing a low temperature resistant low hardness thermoplastic elastomer according to claim 9, wherein: the temperature of the double-screw extruder is controlled at 160-165 ℃, and the rotation frequency of the screw is 4-6 Hz.

Technical Field

The invention relates to a low-temperature-resistant low-hardness thermoplastic elastomer and a preparation method thereof, belonging to the field of high-molecular elastomers.

Background

Dynamically vulcanized thermoplastic elastomers (TPVs) are thermoplastic elastomers prepared by a dynamic vulcanization process. TPVs are mainly composed of two parts, rubber as the dispersed phase and plastic as the continuous phase. In recent years, the thermoplastic elastomer has more and more outstanding application value due to excellent performance, has elasticity of rubber at normal temperature, can have processing performance like thermoplastic plastics when being heated, has simple processing technology, can recycle leftover materials, saves energy, meets the requirement of the latest national environmental protection policy, is widely applied to the fields of automobile materials, electronics, electric wires and cables and the like, and is one of the key development directions of rubber materials in the world.

Styrene Butadiene Rubber (SBR) has the advantages of wide application, mature processing technology, large yield and low price. The blend type styrene-butadiene rubber thermoplastic elastomer is a thermoplastic diene rubber developed in 90 s of 20 th century, and is mainly prepared by mechanically blending styrene-butadiene rubber (SBR) and polyolefin Plastics (PO) such as Polyethylene (PE) or polypropylene (PP) and the like and dynamically vulcanizing. At present, most of blend TPVs still have the defects of high hardness, poor rubber feeling, large permanent deformation and the like. It is common in the industry to add extender oil to reduce the hardness and improve the processability of the material, and the common oil is mainly paraffin oil, naphthenic oil and white oil. Rubber filling oil is obtained by filling oil into rubber at normal temperature and mixing the oil with plastic in a melting way at high temperature, but has the defects of crystallization of the plastic along with temperature reduction, oil precipitation and the like.

In order to make the thermoplastic elastomer material obtained by dynamic vulcanization have certain mechanical properties, fillers such as carbon black and white carbon black are usually added into the blend, but the permanent deformation of the product is large due to poor dispersibility.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: overcomes the defects of the prior art, provides a low-temperature resistant low-hardness thermoplastic elastomer, and has small permanent deformation of products; the invention also provides a preparation method of the composition, which is scientific, reasonable, simple and feasible.

The low-temperature-resistant low-hardness thermoplastic elastomer is prepared from the following raw materials in parts by mass:

the polyisobutylene is low-molecular-weight polyisobutylene, and the molecular weight range is 700-1000.

The mass content of the carbon nano tubes in the styrene butadiene rubber containing the carbon nano tubes is 15-20%.

The preparation method of the powdered styrene-butadiene rubber containing the carbon nano tubes comprises the following steps:

adding deionized water into a coagulator, controlling the temperature at 60-70 ℃, adding 18-22% sodium chloride solution into the coagulator, starting stirring at the stirring speed of 300-.

The carbon nano tube aqueous solution contains modified carbon nano tubes.

The modified carbon nanotube is a carboxyl modified carbon nanotube and is purchased from Shandong Dazhang nanometer materials Co.

The vulcanizing agent is 2, 5-dimethyl-2, 5-di-tert-butyl hexane peroxide.

The accelerant is triacrylate isocyanurate.

The preparation method of the low-temperature-resistant low-hardness thermoplastic elastomer comprises the following steps of:

the preparation method comprises the steps of refining powdered styrene butadiene rubber containing carbon nano tubes, polypropylene resin, polyisobutylene, a vulcanizing agent and an accelerator in an internal mixer to prepare a premix, adding the premix into a double-screw extruder for reaction and extrusion, granulating, and extruding TPV sheets from granules on a Brabender single-screw extruder unit.

The temperature of the double-screw extruder is controlled at 160-165 ℃, and the rotation frequency of the screw is 4-6 Hz.

Preferably, the sample preparation process is: the pellets were extruded into 2mm thick TPV sheets at 170 ℃ and 185 ℃ on a Brabender single screw extruder block and dumbbell test specimens were cut out using a prototype press.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention uses butadiene styrene rubber and polypropylene resin as basic raw materials, adopts dynamic vulcanization technology, uses the co-flocculation process of carbon nanotube emulsion and butadiene styrene rubber emulsion to prepare powdered butadiene styrene rubber containing carbon nanotubes, and mixes the powdered butadiene styrene rubber with polypropylene resin to prepare the low-hardness and low-temperature-resistant thermoplastic elastomer by oil-filling and softening of low-molecular-weight polyisobutylene.

2. In the invention, the carbon nano tube is covered with a layer of film on the surface after being modified, and the carbon nano tube is used as a reinforcing agent while playing a role in isolating styrene-butadiene rubber particles after being condensed, so that the tensile strength, the elongation at break, the wear resistance and the like of the material can be obviously improved.

3. Styrene-butadiene rubber and polypropylene resin have excellent compatibility, but their phase interfaces are still separated. The compatibilizer needs to be added into the system to improve the interface condition between PP and SBR and improve the compatibility. The low molecular weight polyisobutylene is in liquid state, non-toxic, colorless, tasteless, and has brittleness temperature of-90 deg.C; the polyisobutylene has good thermodynamic compatibility with most nonpolar rubbers and plastics, can be blended with the polyisobutylene at any proportion, has good low-temperature resistance, does not precipitate at low temperature, and can be used as a compatilizer and a softener.

4. The invention solves the problem of large permanent deformation caused by poor filler dispersibility by using a co-flocculation process of the carbon nano tube emulsion and the styrene-butadiene rubber emulsion, reduces the hardness of TPV products by filling low molecular weight polyisobutylene, and has excellent low temperature resistance of TPV.

Detailed Description

The present invention will be further described with reference to the following detailed description, but is not limited thereto.

The raw materials used in the examples were as follows:

styrene butadiene rubber emulsion, SBR 1502.

Polypropylene resin, PP 230G.

Styrene butadiene rubber, SBR 1502.

Carbon black, 8 #.

Polyisobutylene, PIB 1300.

2,5 dimethyl-2, 5 di-tert-butylperoxyhexane, BPDH.

Triacrylate isocyanurate, TAIC.

Carboxyl modified carbon nanotubes, available from Shandong Dazhu nanometer materials, Inc.

The preparation method of the powdered styrene-butadiene rubber containing the carbon nano tubes adopted in the embodiment is as follows:

adding deionized water into a coagulator, controlling the temperature at 60 ℃, adding 20% sodium chloride solution into the coagulator, starting stirring, stirring at the rotating speed of 350r/min, adding a carbon nano tube aqueous solution (containing 20% of carboxyl modified carbon nano tubes), uniformly stirring, then adding SBR-1502 emulsion for coagulation reaction, and after coagulation is finished, dehydrating and drying to obtain the carbon nano tube-containing powdered styrene butadiene rubber with the carbon nano tube content of 20%.

Example 1

Weighing 80 parts of carbon nanotube-containing powder styrene butadiene rubber, 20 parts of PP230G, 5 parts of PIB1300, 5 parts of vulcanizing agent BPDH and 1 part of accelerator TAIC, premixing for 5 minutes in an internal mixer to prepare a premix, adding the premix into a double-screw extruder for reaction and extrusion, granulating, controlling the temperature at 160-165 ℃ and the screw rotation frequency at 5Hz, extruding the granules into TPV sheets with the thickness of 2mm on a Brabender single-screw extruder at 170-185 ℃, and cutting the dumbbell-shaped samples by using a sampling machine.

Example 2

Weighing 75 parts of powdered styrene butadiene rubber containing carbon nanotubes, 25 parts of PP230G, 20 parts of PIB1300, 1 part of vulcanizing agent BPDH and 0.1 part of accelerator TAIC, premixing for 5 minutes in an internal mixer to prepare a premix, adding the premix into a double-screw extruder for reaction and extrusion, granulating, controlling the temperature at 160-90 ℃ and the screw rotation frequency at 5Hz, extruding the granules into TPV sheets with the thickness of 2mm on a Brabender single-screw extruder at 170-185 ℃, and cutting the dumbbell-shaped samples by using a sampling machine.

Example 3

Weighing 68 parts of carbon nanotube-containing powder styrene butadiene rubber, 32 parts of PP230G, 10 parts of PIB1300, 3 parts of vulcanizing agent BPDH and 0.5 part of accelerator TAIC, premixing for 5 minutes in an internal mixer to prepare a premix, adding the premix into a double-screw extruder for reaction and extrusion, granulating, controlling the temperature at 160-165 ℃ and the screw rotation frequency at 5Hz, extruding the granules into TPV sheets with the thickness of 2mm on a Brabender single-screw extruder at 170-185 ℃, and cutting the dumbbell-shaped samples by using a sampling machine.

Comparative example 1

Weighing 68 parts of SBR1502 block rubber, 32 parts of PP230G, 10 parts of naphthenic oil, 20 parts of carbon black, 3 parts of vulcanizing agent BPDH and 0.5 part of accelerator TAIC, premixing for 5 minutes in an internal mixer to prepare a premix, adding the premix into a double-screw extruder, reacting, extruding and granulating, controlling the temperature at 160-90 ℃ and the screw rotation frequency at 5Hz, extruding the granules into TPV sheets with the thickness of 2mm on a Brabender single-screw extruder at 170-185 ℃, and cutting the dumbbell type samples by using a sampling machine.

Comparative example 2

Weighing 68 parts of SBR1502 block rubber, 32 parts of PP230G, 10 parts of liquid paraffin, 20 parts of carbon black, 3 parts of vulcanizing agent BPDH and 0.5 part of accelerator TAIC, premixing for 5 minutes in an internal mixer to prepare a premix, adding the premix into a double-screw extruder, reacting, extruding and granulating, controlling the temperature at 160-90 ℃ and the screw rotation frequency at 5Hz, extruding the granules into TPV sheets with the thickness of 2mm on a Brabender single-screw extruder at 170-185 ℃, and cutting the dumbbell-shaped samples by using a sampling machine.

Comparative example 3

Weighing 68 parts of SBR1502 block rubber, 32 parts of PP230G, 10 parts of white oil, 20 parts of carbon black, 3 parts of vulcanizing agent BPDH and 0.5 part of accelerator TAIC, premixing for 5 minutes in an internal mixer to prepare a premix, adding the premix into a double-screw extruder for reaction and extrusion, granulating, controlling the temperature to be 160-plus-165 ℃ and the screw rotation frequency to be 5Hz, extruding the granules into TPV sheets with the thickness of 2mm on a Brabender single-screw extruder at the temperature of 170-plus 185 ℃, and cutting the dumbbell-shaped samples by using a sampling machine.

The samples prepared in examples 1 to 3 and comparative examples 1 to 3 were subjected to the performance test, and the test results are shown in Table 1.

TABLE 1 SBR/PP-TPV Performance test results

As shown in the table, the SBR powder containing 20% carbon nano tubes is mixed with polypropylene resin and filled with the low molecular weight polyisobutylene PIB1300, so that the SBR/PP-TPV with small permanent deformation, low hardness and excellent low temperature resistance can be prepared, and the SBR/PP-TPV powder can be widely applied to the fields of automobile materials, electronics, wires and cables and the like.

Of course, the foregoing is only a preferred embodiment of the invention and should not be taken as limiting the scope of the embodiments of the invention. The present invention is not limited to the above examples, and equivalent changes and modifications made by those skilled in the art within the spirit and scope of the present invention should be construed as being included in the scope of the present invention.