Green room-temperature high-damping thermoplastic elastomer composite material and preparation method thereof

Abstract

The invention discloses a green room-temperature high-damping thermoplastic elastomer composite material and a preparation method thereof. According to the invention, hydrogenated styrene resin is used as a continuous phase, and halogenated butyl rubber is used as a dispersed phase to form a sea-island two-phase structure of the thermoplastic elastomer. Flaky nano-clay is selected as a functional filler, low-molecular-weight polyisobutene is selected as a processing aid, traditional damping fillers or aids such as hindered phenol, petroleum resin and polyvinyl chloride resin are not required to be added, a vulcanizing agent required by traditional rubber is not required to be added, and an irradiation vulcanization crosslinking process is not required. The green damping thermoplastic elastomer composite material with the loss factor greater than 0.9 can be obtained at the room temperature of 22 DEG C. The tensile strength of the composite material is greater than 15 MPa, the elongation is greater than 300%, and the composite material has excellent physical and mechanical properties; after three times of recycling and repeated processing, the physical and mechanical property retention rate is still excellent, the excellent repeatable processability is realized, and the loss factor retention rate at 22 DEG C is greater than 95%.

Description

Technical Field

[0001] The invention belongs to the technical field of functional polymer composite materials, and in particular relates to a green room temperature high damping thermoplastic elastomer composite material and a preparation method thereof. Background Art

[0002] With the development of science and technology, large precision instruments, mechanical equipment, electronic instruments, and components tend to be high-speed, efficient, and automated, and the vibration, noise, excessive wear, and fatigue fracture caused by system operation are becoming more and more prominent. Rubber materials have unique dynamic viscoelasticity and large hysteresis loss. They have obvious advantages in absorbing large-amplitude vibrations and low-energy long-wave vibrations. They have broad application prospects in damping fields such as large precision instruments, mechanical equipment, building bridge shock absorption, and submarine silencing. Nano-damping technology is one of the important methods to control structural resonance and noise.

[0003] Common rubber nano-damping technology, rubber damping material refers to a functional material that can convert mechanical vibration into heat energy or other forms of energy to absorb most or even all vibrations. The damping loss process is usually accompanied by energy conversion, and the strong internal friction generated by the relaxation movement of the rubber macromolecular chain segments is converted into heat energy and dissipated.

[0004] Most of the damping composite materials on the market are rubber-based, and sulfur-containing compounds need to be added as vulcanizing agents. They are formed by hot vulcanization, and the chemical cross-linking characteristics make them non-recyclable. At present, high-damping rubber materials are often based on butyl rubber, nanofillers and vulcanizing agents, which are obtained by mixing, kneading and high-temperature vulcanization. Nanofillers are mainly carbon black, modified white carbon black, flaky mica and lamellar kaolin, which can have a high loss factor below 0 ℃. However, at room temperature of 22 ℃, the loss factor of traditional high-damping rubber is very low, and hindered phenol damping fillers need to be added. However, with the increase in the amount of hindered phenol, the compatibility of hindered phenol fillers with rubber substrates varies greatly. After the material has been parked for a long time, some hindered phenol small molecules will migrate to the surface of the product, forming frost, which seriously affects the appearance quality of the product.

[0005] Therefore, it is in line with the development needs of green environmental protection to study a reusable damping rubber composite material suitable for damping at room temperature of 22 ℃ without adding damping fillers and vulcanizers. On the one hand, it is necessary to select a suitable elastomer material as the continuous phase to ensure the basic performance and repeated processing of the rubber composite material; on the other hand, it is necessary to select a suitable dispersed phase structure to achieve high damping characteristics and obtain the preparation of a green high damping thermoplastic elastomer composite material. Summary of the invention

[0006] In order to solve the technical problems existing in the existing products, the present invention provides a green room temperature high damping thermoplastic elastomer composite material and a preparation method thereof. The present invention uses hydrogenated styrene resin as a continuous phase and halogenated butyl rubber as a dispersed phase to form a "sea and island" two-phase structure of a thermoplastic elastomer. Flaky nanoclay is selected as a functional filler, and low molecular weight polyisobutylene is selected as a processing aid. There is no need to add damping fillers or additives such as traditional hindered phenols, petroleum resins, polyvinyl chloride resins, etc., and there is no need to add vulcanizers required for traditional rubbers, and no radiation vulcanization cross-linking process is required. Instead of using butyl rubber alone in the prior art, it still has the effect of high damping loss at 22°C after repeated use.

[0007] The raw material composition of the green room temperature high damping thermoplastic elastomer composite material includes, by mass: 50-95 parts of hydrogenated styrene resin, preferably 60-90 parts; 5-50 parts of halogenated butyl rubber, preferably 10-40 parts; 5-80 parts of flaky nanoclay, preferably 10-40 parts; 2-20 parts of polyisobutylene, preferably 3-10 parts; 1-5 parts of antioxidant, preferably 2-4 parts; The hydrogenated styrene resin and the halogenated butyl rubber accounted for 100 parts in total.

[0008] The hydrogenated styrene resin is a hydrogenated styrene-butadiene block copolymer (SEBS). The hydrogenated styrene-butadiene block copolymer is obtained by hydrogenating the polybutadiene chain segments in SBS to form polyethylene chain segments and polybutylene chain segments. SEBS not only has the dual properties of plasticization and rubber, but also has better light-oxidation aging resistance, thermal stability and weather resistance compared to SBS due to the high saturation of the main chain.

[0009] The styrene content of the hydrogenated styrene resin is 33-60%, preferably 40-55%.

[0010] The hydrogenated styrene-butadiene block copolymer is a hydrogenated polystyrene-polybutadiene-polystyrene block copolymer.

[0011] The halogenated butyl rubber is chlorinated butyl rubber and / or brominated butyl rubber. The halogenated butyl rubber has dense methyl groups, large steric hindrance and a wide damping temperature range.

[0012] The Mooney viscosity of the halogenated butyl rubber is ML (1+8) at 125°C: 20-50, preferably 30-40. The halogen content of the halogenated butyl rubber is 0.5-3%, preferably 1-2%.

[0013] The flaky nanoclay is a lamellar silicon-containing mineral material; the average diameter of the flaky layer is 300-500 nm, and the average thickness of the flaky layer is 30-50 nm. The lamellar nanoclay filler has good reinforcement performance and good flexibility, and can be used as a good energy dissipation carrier in terms of damping loss.

[0014] The flaky nanoclay is nano-montmorillonite and / or nano-rectorite.

[0015] The polyisobutylene is a polymer obtained by cationic polymerization of isobutylene, and has good flexibility and processability. The average molecular weight of the polyisobutylene is 680-2400.

[0016] The antioxidant is a primary antioxidant and a secondary antioxidant in a mass ratio of 1-3:1, preferably 1-2:1; the primary antioxidant is an amine antioxidant; and the secondary antioxidant is a phenolic antioxidant.

[0017] The amine antioxidant is one or more of 2,2,4-trimethyl-1,2-dihydroquinoline (antioxidant RD), 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (antioxidant MB), octylated diphenylamine, and 4.4'-bis(2.2-dimethylbenzyl)diphenylamine (antioxidant 445).

[0018] The phenolic antioxidant is one or more of styrenated phenol (antioxidant SP), 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246), and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1010).

[0019] The preparation method of the green room temperature high damping thermoplastic elastomer composite material is: The hydrogenated styrene resin, halogenated butyl rubber, flaky nano clay, polyisobutylene and antioxidant are mixed in an open mill, sheared and mixed by a twin-screw, water-cooled and pelletized to obtain a green room temperature high-damping thermoplastic elastomer composite material.

[0020] The mixing temperature is 100-150°C and the mixing time is 10-20 minutes.

[0021] The temperature of each heating section of the twin screw is 180-230° C., and the screw speed is 200-300 r / min.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention can obtain a green damping thermoplastic elastomer composite material with a loss factor greater than 0.9 at room temperature 22°C without adding damping fillers such as hindered phenol, petroleum resin, polyvinyl chloride resin, etc.; (2) The present invention does not require the addition of a vulcanizing agent or radiation cross-linking to obtain a damping composite material having a tensile strength greater than 15 MPa, an elongation greater than 300%, and excellent physical and mechanical properties; (3) The green high-damping thermoplastic composite material involved in the present invention has excellent reproducibility. After three times of recycling and repeated processing, the retention rate of physical and mechanical properties is still excellent, with a tensile strength retention rate of more than 75%, a tear elongation retention rate of more than 95%, a right-angle tear strength retention rate of more than 95%, a DMA test maximum loss factor retention rate of more than 95%, and a 22°C loss factor retention rate of more than 95%. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0024] The raw materials used in the examples and comparative examples are all conventional commercially available raw materials.

[0025] The amount of each raw material used in the examples and comparative examples is based on mass fraction.

[0026] Reference standards for performance testing: Mechanical properties test: GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber; Right-angle tear test: GB / T 529-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber; DMA test: GB / T 9870.1-2006 Determination of dynamic properties of vulcanized rubber or thermoplastic rubber Part 1: General.

[0027] Comparative Example 1 The recipe is shown in Table 1.

[0028] Compared with Examples 1 to 3, Comparative Example 1 did not add halogenated butyl rubber; The styrene content of the SEBS used is 45%, the flaky nanoclay is nano-montmorillonite, the dosage is 20 parts by weight, the main antioxidant is diphenylamine antioxidant 445, the auxiliary antioxidant is hindered phenol antioxidant 1010, and the molecular weight of polyisobutylene is 680. The preparation process conditions are as follows: accurately weigh the mass ratio of each component of the comparative example in Table 1, mix on an electric heating open mill for 10 minutes at a temperature of 130°C, and obtain a uniformly dispersed mixture. The above mixture is mixed and kneaded by a twin-screw extruder, the aspect ratio of the twin screw is 48:1, the temperatures of each heating section are 180 ℃, 190 ℃, 195 ℃, 200 ℃, 200 ℃, 205 ℃, 205 ℃, 210 ℃, 210 ℃, 215 ℃, 200 ℃, the screw speed is 280 r / min, and after shear mixing by the twin screw, it is water-cooled and pelletized to obtain thermoplastic composite particles.

[0029] Comparative Example 2 The recipe is shown in Table 1.

[0030] Compared with Examples 1 to 3, Comparative Example 2 did not add SEBS; The halogenated butyl rubber used is ExxonMobil's CIIR1066, with a chlorine content of 1.3% and a Mooney viscosity (ML1+8, 125°C) of 38. The flaky nanoclay is nano-montmorillonite, with an amount of 20 parts by mass. The main antioxidant is diphenylamine antioxidant 445, the auxiliary antioxidant is hindered phenol antioxidant 1010, the molecular weight of polyisobutylene is 680, the vulcanizing agent is sulfur and tetramethylthiuram disulfide (accelerator TMTD), and the activator is zinc oxide. The preparation process conditions are as follows: accurately weigh the mass ratio of each component of the comparative example in Table 1, mix on an open mill for 10 min at a temperature of 55°C to obtain a uniformly dispersed mixture. The vulcanized rubber sheet is obtained by a flat plate vulcanizer at 170°C × 20 min and a pressure of 15 MPa.

[0031] Example 1 The recipe is shown in Table 1.

[0032] The styrene content of the SEBS used is 55%, and the dosage is 90 parts by mass. The halogenated butyl rubber is ExxonMobil CIIR1066 with a chlorine content of 1.3%, a Mooney viscosity (ML1+8, 125°C) of 38, and the dosage is 10 parts by mass. The flaky nanoclay is nano-montmorillonite, and the dosage is 30 parts by mass. The main antioxidant is diphenylamine antioxidant MB, the auxiliary antioxidant is antioxidant 2246, and the molecular weight of polyisobutylene is 2400. The preparation process conditions are as follows: accurately weigh the mass ratio of each component in Table 1, mix on an electric heating open mill for 12 minutes, and the temperature is 130°C to obtain a uniformly dispersed mixture. The above mixture is mixed and kneaded through a twin-screw extruder, and the mixture after open kneading is mixed and kneaded through a twin-screw extruder, the aspect ratio of the twin screw is 48:1, the temperatures of each heating section are 185 ℃, 190 ℃, 195 ℃, 210 ℃, 210 ℃, 215 ℃, 215 ℃, 220 ℃, 220 ℃, 225 ℃, 210 ℃, the screw speed is 240 r / min, and after twin-screw shearing and kneading, it is water-cooled and pelletized to obtain high damping thermoplastic composite particles.

[0033] Example 2 The recipe is shown in Table 1.

[0034] The styrene content of the SEBS used is 45%, the dosage is 80 parts by mass, the halogenated butyl rubber is ExxonMobil BIIR2222, the bromine content is 2.0%, the Mooney viscosity (ML1+8, 125°C) is 32, the dosage is 20 parts by mass, the flaky nanoclay is nanorectorite, the dosage is 20 parts by mass, the main antioxidant is diphenylamine antioxidant 445, the auxiliary antioxidant is hindered phenol antioxidant 2246, and the molecular weight of polyisobutylene is 680. The preparation process conditions are as follows: accurately weigh the mass ratio of each component in Table 1, mix on an electric heating open mill for 10 minutes, the temperature is 125°C, and a uniformly dispersed mixture is obtained. The above mixture is mixed and kneaded by a twin-screw extruder, the twin-screw aspect ratio is 48:1, the temperatures of each heating section are 190°C, 200°C, 205°C, 210°C, 210°C, 215°C, 215°C, 220°C, 220°C, 225°C, 210°C, the screw speed is 280 r / min, and after twin-screw shearing and kneading, it is water-cooled and pelletized to obtain high damping thermoplastic composite particles.

[0035] Example 3 The recipe is shown in Table 1.

[0036] The styrene content of the SEBS used is 45%, the dosage is 70 parts by mass, the halogenated butyl rubber is ExxonMobil CIIR1066, the chlorine content is 1.3%, the Mooney viscosity (ML1+8, 125°C) is 38, the dosage is 30 parts by mass, the flaky nanoclay is nano-montmorillonite, the dosage is 20 parts by mass, the main antioxidant is diphenylamine antioxidant 445, the auxiliary antioxidant is hindered phenol antioxidant 1010, and the molecular weight of polyisobutylene is 2400. The preparation process conditions are as follows: accurately weigh the mass ratio of each component in Table 1, mix on an electric heating open mill for 10 minutes, the temperature is 120°C, and a uniformly dispersed mixture is obtained. The above mixture is mixed and kneaded by a twin-screw extruder with a twin-screw aspect ratio of 48:1, the temperatures of each heating section are 195 ℃, 205 ℃, 210 ℃, 215 ℃, 215 ℃, 220 ℃, 225 ℃, 225 ℃, 225 ℃, 230 ℃, and 210 ℃, and the screw speed is 220 r / min. After twin-screw shearing and kneading, the mixture is water-cooled and pelletized to obtain high damping thermoplastic composite particles.

[0037] Table 1 Formulas of Comparative Examples and Examples 1 to 3 (by mass)

[0038] The sheet preparation process of Comparative Example 1 and Examples 1 to 3 is as follows: the prepared composite material particles are thinned, triangular-packaged, plasticized, and sheeted on an open mixing mill (roller temperature of the mixing mill is 130°C), hot-pressed (170°C×10min, 10MPa) by a flat vulcanizer, and then cold-pressed (40°C, 15min) to obtain a high-damping sheet of 100mm×100mm×1mm.

[0039] The sheet preparation process of Comparative Example 2 is as follows: the prepared mixed rubber is re-mixed on an open mixing mill for 3 times to produce a sheet, which is vulcanized on a flat vulcanizer (170°C×20min, 15MPa) to obtain a vulcanized rubber sheet with a size of 100mm×100mm×1.0mm.

[0040] The sheets of comparative examples and examples 1 to 3 were tested for mechanical properties, DMA tests and repeated processing performance, and the test results are listed in Table 2. (DMA test conditions: tensile mode, frequency 10 Hz, elongation 0.3%, temperature rise 3 ° C / min).

[0041] The preparation process of recycling and repeated processing is as follows: the sheet is cut into small pieces with a length and width of 1-10 mm, thinned, triangular-wrapped, plasticized, and sheeted on an open mill (roller temperature of the open mill is 130°C), hot-pressed (170°C×10min, 10MPa) by a flat vulcanizer, and then cold-pressed (40°C, 15min) to obtain a 100mm×100mm×1mm high-damping sheet. This process is repeated 3 times.

[0042] Table 2 Performance test results of the sheets and wires of Examples 1 to 3 and the comparative example

[0043] The key performance indicators of high damping materials are as follows: sheet tensile strength ≥ 15 MPa, elongation ≥ 300%, and 22°C loss factor tanδ ≥ 0.9. As can be seen from Table 2, after the sheets of Examples 1 to 3 were processed three times, the strength retention rate was above 75%, the elongation at break retention rate was above 97%, and the tear strength retention rate was above 95%, and the mechanical properties were good. The maximum loss factor at 22°C was still greater than 0.9 after three repeated processings, and had excellent room temperature damping characteristics.

[0044] Compared with Comparative Example 1, 10 to 30 parts by mass of halogenated butyl rubber are added in Examples 1 to 3. After three times of recycling and repeated processing, the tensile strength retention rate of Comparative Example 1 is only 42.5%, and the elongation at break retention rate is only 77.4%; after three recycling cycles, the tensile strength retention rate of Example 1 is 93%, and the elongation retention rate is 109.7%; after three recycling cycles, the tensile strength retention rate of Example 2 is 76.6%, and the elongation retention rate is 97.4%; after three recycling cycles, the tensile strength retention rate of Example 3 is 91.5%, and the elongation retention rate is 144.4%. The results show that after the introduction of halogenated butyl rubber, after three recycling and repeated processing, the tensile strength retention rate of the material is greater than 75%, and the elongation retention rate is greater than 95%, indicating that the green room temperature damping thermoplastic elastomer composite material proposed in the present application has excellent repeatable processing performance.

[0045] No SEBS is added in Comparative Example 2, which belongs to the damping material of the traditional halogenated butyl rubber system. It needs to introduce additional sulfur vulcanizing agent, introduce chemical crosslinking, and cannot be recycled for repeated processing. The maximum loss factor of Comparative Example 2 at 22 ℃ is 0.59, which is much smaller than the maximum loss factor of the material of the present application, and the damping performance at room temperature is poor. In addition, the tensile strength of Comparative Example 2 is 6.5MPa, which is much lower than the thermoplastic elastomer material proposed in the present application, and the physical and mechanical properties are poor.

[0046] In Comparative Example 1, no halogenated butyl rubber was added, and the tensile strength and elongation retention rates were lower than those of the examples. From the tear strength performance, the tear strength retention rates of the examples were all above 95%, indicating that the use of halogenated butyl rubber as the dispersed phase can effectively improve the tear resistance of SEBS as the main chain continuous phase.

Claims

1. A green room temperature high damping thermoplastic elastomer composite material, characterized in that: The raw material composition of the composite material includes, by weight: 50-95 parts of hydrogenated styrene resin, preferably 60-90 parts; 5-50 parts of halogenated butyl rubber, preferably 10-40 parts; 5-80 parts of flaky nanoclay, preferably 10-40 parts; 2-20 parts of polyisobutylene, preferably 3-10 parts; 1-5 parts of antioxidant, preferably 2-4 parts; The hydrogenated styrene resin and the halogenated butyl rubber accounted for 100 parts in total.

2. The green room temperature high damping thermoplastic elastomer composite material according to claim 1, characterized in that: The hydrogenated styrene resin is a hydrogenated styrene-butadiene block copolymer; the styrene content in the hydrogenated styrene resin is 33-60%, preferably 40-55%.

3. The green room temperature high damping thermoplastic elastomer composite material according to claim 1, characterized in that: The halogenated butyl rubber is chlorinated butyl rubber and / or brominated butyl rubber; the halogen content in the halogenated butyl rubber is 0.5-3%, preferably 1-2%.

4. The green room temperature high damping thermoplastic elastomer composite material according to claim 1, characterized in that: The flaky nanoclay is a flaky silicon-containing mineral material; the average diameter of the flaky layer is 300-500 nm, and the average thickness of the flaky layer is 30-50 nm.

5. The green room temperature high damping thermoplastic elastomer composite material according to claim 1, characterized in that: The polyisobutylene is a polymer obtained by cationic polymerization of isobutylene; the average molecular weight of the polyisobutylene is 680-2400.

6. The green room temperature high damping thermoplastic elastomer composite material according to claim 1, characterized in that: The antioxidant is composed of a primary antioxidant and a secondary antioxidant in a mass ratio of 1-3:1, preferably 1-2:1; the primary antioxidant is an amine antioxidant; and the secondary antioxidant is a phenolic antioxidant.

7. The green room temperature high damping thermoplastic elastomer composite material according to claim 6, characterized in that: The amine antioxidant is one or more of 2,2,4-trimethyl-1,2-dihydroquinoline, 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, octylated diphenylamine, and 4.4'-bis(2.2-dimethylbenzyl)diphenylamine; The phenolic antioxidant is one or more of styrenated phenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

8. The method for preparing a green room temperature high damping thermoplastic elastomer composite material according to any one of claims 1 to 7, characterized in that: The specific operation of the preparation method is: mixing hydrogenated styrene resin, halogenated butyl rubber, flaky nano clay, polyisobutylene and antioxidant in an open mill, shearing and mixing with a twin-screw, water cooling and pelletizing to obtain a green room temperature high-damping thermoplastic elastomer composite material.

9. The preparation method according to claim 8, characterized in that: The mixing temperature is 100-150°C and the mixing time is 10-20 minutes.

10. The preparation method according to claim 8, characterized in that: The temperature of each heating section of the twin screw is 180-230° C., and the screw speed is 200-300 r / min.

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