Silica gel modified polyolefin elastomer and preparation method thereof

Abstract

The invention discloses a silica gel modified polyolefin elastomer material and a dynamic vulcanization preparation method thereof. An SEBS / POE blend is used as matrix resin, a certain amount of directionally hydrogenated SEBS and silane modified POE are added to serve as reactive compatilizers, vinyl silicone rubber and filler are matched, and crosslinking and dispersion of silica gel in the SEBS / POE blend are achieved through a dynamic vulcanization process. In the formula, directionally hydrogenated SEBS and silica gel can be subjected to an in-situ cross-linking reaction through hydrogen-containing silicone oil, silane modified POE and silicone rubber can be condensed, a double-cascade compatibility mechanism is constructed through cooperation of SEBS and silane modified POE, and the compatibility effect is enhanced. The content of SEBS / POE / silica gel is adjusted through the hardness prediction model, precise control over the hardness is achieved, and the obtained silica gel modified polyolefin elastomer material has excellent mechanical properties and good touch feeling and is suitable for the high-end fields of consumer electronics shells, wearable devices and the like.

Description

Technical Field

[0001] This invention belongs to the field of dynamic vulcanized thermoplastic elastomer technology, specifically relating to a silicone-modified polyolefin elastomer and its preparation method. Background Technology

[0002] Dynamic vulcanization is an important method for preparing thermoplastic elastomers. First proposed by Gessler and further developed by Fisher et al., it was industrially applied after Dr. Coran successfully prepared fully vulcanized EPDM / PP TPV for the first time. This technology involves melt-blending unvulcanized raw rubber with an unvulcanizable thermoplastic polymer in a high-temperature, high-shear blending device, while simultaneously vulcanizing the rubber phase under the action of a crosslinking agent. This results in a stable structure where micron-sized vulcanized rubber particles are uniformly dispersed in the resin. Unlike traditional static vulcanization, it offers advantages such as high efficiency, energy saving, and recyclability, and is widely used in the automotive, electronics, and construction industries.

[0003] Despite the numerous advantages of dynamic vulcanization technology, the compatibility between silicone and different polymers has remained a key challenge hindering further performance improvements in practical applications. Differences in polarity and molecular structure among the polymers involved in the blending often lead to poor compatibility, thus affecting the material's mechanical properties, durability, and processability.

[0004] To address this issue, existing technologies employ various methods. Patent CN112011185B proposes a dual-premixed dynamic vulcanization process, which incorporates compatibilizers such as ethylene-methyl acrylate copolymer (EMA) and ethylene-methyl acrylate-glycidyl methacrylate random terpolymer (EMA-g-GMA), but these compatibilizers generally have poor compatibility with silicone. Patents CN1429253A and CN114369366B use hydroxyl-terminated silicone oil, epoxy silicone oil, or silane coupling agents as compatibilizers. These compatibilizers exhibit good compatibility with silicone but poor compatibility with general-purpose resins, resulting in weak overall compatibility. Patent CN109553982A uses silicone-modified polyurethane, ethylene-vinyl acetate copolymer grafted silicone rubber, or maleic anhydride grafted silicone rubber as compatibilizers. This improves interfacial compatibility through molecular chain physical entanglement, but the interfacial bonding force is weak.

[0005] While these existing patents have improved the compatibility of silicone and resin to some extent, they still have problems such as poor compatibility, weak interaction with resin, poor processing performance, and insufficient stability, which limit the application and development of silicone and resin systems in a wider range of fields. Summary of the Invention

[0006] In the dynamic vulcanization process of current polyolefin / silicone thermoplastic elastomers, the poor compatibility between silicone rubber and polyolefin leads to poor dispersion of silicone rubber, resulting in poor mechanical properties and a rough surface of the obtained thermoplastic elastomer. Furthermore, the hardness of two-component or three-component systems is unpredictable, making it difficult to directly obtain the final hardness through formulation, thus increasing the difficulty of formulation design.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A silicone-modified polyolefin elastomer material, comprising the following raw materials in parts by weight:

[0009] 30-50 parts SEBS, 20-35 parts POE, 3-8 parts directional hydrogenated SEBS, 1.5-5 parts silane-modified POE, 20-40 parts methyl vinyl silica gel, 1.2-2.5 parts crosslinking agent, and 1-10 parts filler.

[0010] In one specific embodiment, the SEBS has a styrene content of 10-35% by mass, a melt index of 0.1-10 g / 10 min (200℃ / 5 kg), preferably 0.2-8 g / 10 min (200℃ / 5 kg), and a hardness range of 40-60A.

[0011] In one specific embodiment, the styrene content of the directional hydrogenated SEBS is 15-50% by mass, and the melt index is 0.5-10 g / 10 min (200℃ / 5 kg), preferably 0.5-5 g / 10 min (200℃ / 5 kg);

[0012] In one specific embodiment, the POE melt flow index is 1-20 g / 10 min (190℃ / 2.16 kg), preferably 1-10 g / 10 min (190℃ / 2.16 kg); the hardness range is 60-85A.

[0013] In one specific embodiment, the modifier for the silane-modified POE is selected from one or more of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane, and the grafting rate of the modifier is 1-5 wt%. The α-olefin of the silane-modified POE is preferably 1-octene.

[0014] In one specific embodiment, the methyl vinyl silica gel is selected from vinyl-terminated or methyl-terminated vinyl silica gels, with a vinyl molar content of 0.03-1%, preferably 0.03-0.2%, and a molecular weight of 450,000-1,200,000;

[0015] In one specific embodiment, the crosslinking agent is a hydrogen-containing silicone oil, selected from one or more of end-containing hydrogen-containing silicone oil, side-containing hydrogen-containing silicone oil, and end-side hydrogen-containing silicone oil, with a hydrogen content of 0.01-2 wt%, preferably 0.5-1.6%.

[0016] In one specific embodiment, the filler is selected from one or more of silica, talc, and antioxidants (e.g., 1010, 1135, 168).

[0017] On the other hand, the present invention provides a dynamic vulcanization preparation method for the silicone-modified polyolefin elastomer material, comprising the following steps:

[0018] (1) Premixing: Add 30-50 parts of SEBS, 20-35 parts of POE, 3-8 parts of directional hydrogenated SEBS, 1.5-5 parts of silane-modified POE, 20-40 parts of methyl vinyl silica gel, 1.2-2.5 parts of crosslinking agent, and 1-10 parts of filler to a kneader or internal mixer and mix them, and then granulate them by extrusion.

[0019] (2) Dynamic vulcanization: The product obtained in step (1) is mixed with the catalyst through a mixer and added to a twin-screw extruder for dynamic vulcanization reaction, and granulated to obtain silicone-modified polyolefin elastomer.

[0020] In one specific embodiment, the temperature of premixing in step (1) is 170-210℃ and the mixing time is 5-20 min; the temperature of dynamic vulcanization in step (2) is 180-220℃ and the dynamic vulcanization time is 1-10 min.

[0021] In one specific embodiment, the catalyst is a Castells platinum catalyst with a platinum content of 1000-10000 ppm;

[0022] Furthermore, the catalyst content in the silicone-modified thermoplastic elastomer is 3-30 ppm.

[0023] The elastomer of the present invention has a hardness (in Å) that conforms to the following hardness prediction model:

[0024]

[0025] In the formula,

[0026] A represents the mass content of SEBS in the elastomer. For example, if the mass content is 40 wt%, the value of A is 0.4.

[0027] B represents the hardness of SEBS.

[0028] C represents the POE content;

[0029] D represents the hardness of POE;

[0030] E represents the silica gel content;

[0031] F represents the filler content.

[0032] In the method of this invention, the hardness of the thermoplastic elastomer after dynamic vulcanization modification of silicone can be directly calculated from the formula through the above prediction model, thereby achieving precise control of the material hardness.

[0033] The beneficial effects of this invention are as follows:

[0034] Firstly, the directional hydrogenation of SEBS, under the action of a platinum catalyst, achieves interfacial compatibility through a co-crosslinking reaction between hydrogen-containing silicone oil and vinyl silicone, effectively solving the problem of poor compatibility between silicone and resin.

[0035] Secondly, silane-modified POE can react with the hydroxyl groups on the surface of silica gel through hydrolysis to generate a Si-O-Si structure, which works synergistically with directional hydrogenated SEBS to construct a dual-step compatibility mechanism, significantly improving the compatibility and tactile feel of the material.

[0036] Third, by using appropriate mathematical models to predict the hardness of the thermoplastic elastomer obtained from the formulation, and by precisely adjusting the formulation and process, the hardness can be precisely controlled to meet the specific hardness requirements of different application scenarios.

[0037] The solution of this invention significantly improves the overall performance of the material, making it outstanding in terms of tactile feel, compatibility, and mechanical properties, and has broad application prospects. Detailed Implementation

[0038] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for the purpose of better understanding the invention and do not imply that the invention is limited to these embodiments.

[0039] Information on the source of main raw materials:

[0040] SEBS: G1657 (hardness 47A, styrene 13wt%, melt index 8g / 10min (200℃ / 5kg)), G1651 (hardness 60A, styrene 33wt%, melt index 0.2g / 10min (200℃ / 5kg)), Kraton Corporation;

[0041] Directed hydrogenation of SEBS: Q5501 (49wt% styrene, melt index 0.82g / 10min (200℃ / 5kg)), Zhejiang Zhongli Synthetic Materials Technology Co., Ltd.

[0042] POE: Model 65056 (hardness 63A, melt flow index 5g / 10min (190℃ / 2.16kg)), 5057 (hardness 70A, melt flow index 5g / 10min (190℃ / 2.16kg)), 5018 (hardness 85A, melt flow index 1g / 10min (190℃ / 2.16kg)), Wanhua Chemical;

[0043] Methyl vinyl silicone: Model 110-0 (vinyl-terminated, vinyl content 0.03-0.06%, molecular weight 640,000), 110-2 (vinyl-terminated, vinyl content 0.07-0.12%, molecular weight 650,000), 112-0 (methyl-terminated, vinyl content 0.03-0.06%, molecular weight 640,000), Hesheng Silicon Industry Co., Ltd.;

[0044] Hydrogen-containing silicone oils: SES004 (side-containing hydrogen, hydrogen content 1.5%), HCA468 (side-containing hydrogen, hydrogen content 0.75%), Senri Organosilicon Materials Co., Ltd.

[0045] Castor platinum catalyst: CAST-F60050 (platinum content 5000ppm), Suzhou Betterley Polymer Materials Co., Ltd.;

[0046] Silane-modified POE: R1020, KOS Chemical Co., Ltd.;

[0047] Main testing methods

[0048] Hardness was tested according to ASTM D4420.

[0049] Tensile strength and elongation at break were tested according to ASTM D412.

[0050] Tear strength was tested according to ASTM D624.

[0051] Compression set was tested according to ASTM D395, under the conditions of 25°C / 24H.

[0052] Example 1

[0053] 40 parts of SEBS (G1657), 25 parts of POE (5018), 4 parts of directional hydrogenated SEBS, 3 parts of silane-modified POE, 23 parts of vinyl silicone (110-0), 2 parts of crosslinking agent SES004, 1 part of silica, 1 part of talc, and 1 part of antioxidant 1010 were added to a kneader and mixed at 190°C for 8 min. The mixture was then extruded and granulated using a single-screw extruder to obtain a premix. The premix was then mixed with 10 ppm of catalyst and added to a twin-screw extruder for dynamic vulcanization. The mixture was mixed at 200°C and 400 r / min for 4 min, and then granulated to obtain silicone-modified polyolefin elastomer.

[0054] Example 2

[0055] 50 parts of SEBS (G1651), 20 parts of POE (5018), 3.7 parts of directional hydrogenated SEBS, 2 parts of silane-modified POE, 20 parts of vinyl silicone (110-2), 2.3 parts of crosslinking agent SES004, 1 part of silica, and 1 part of antioxidant 1010 were added to a kneader and mixed at 180°C for 15 min. The mixture was then extruded and granulated using a single-screw extruder to obtain a premix. The premix was then mixed with 8 ppm of catalyst and added to a twin-screw extruder for dynamic vulcanization. The mixture was stirred and reacted at 210°C and 450 r / min for 7 min. Granulation was then performed to obtain a silicone-modified polyolefin elastomer.

[0056] Example 3

[0057] 30 parts SEBS (G1657), 35 parts POE (5057), 3 parts directional hydrogenated SEBS, 3.5 parts silane-modified POE, 24 parts vinyl silicone (112-0), 2.5 parts crosslinking agent HCA468, 1 part silica, and 1 part antioxidant 1010 were added to a kneader and mixed at 200°C for 6 min. The mixture was then extruded and granulated using a single-screw extruder to obtain a premix. The premix was then mixed with 15 ppm catalyst and added to a twin-screw extruder for dynamic vulcanization. The mixture was stirred and reacted at 190°C for 3 min at 500 r / min and granulated to obtain a silicone-modified polyolefin elastomer.

[0058] Example 4

[0059] 30 parts of SEBS (G1657), 20 parts of POE (65056), 3.1 parts of directional hydrogenated SEBS, 1.5 parts of silane-modified POE, 40 parts of vinyl silicone (110-0), 2.4 parts of crosslinking agent SES004, 1 part of silica, 1 part of talc, and 1 part of antioxidant 1010 were added to a kneader and mixed at 210°C for 10 min. The mixture was then extruded and granulated using a single-screw extruder to obtain a premix. The premix was then mixed with 25 ppm of catalyst and added to a twin-screw extruder for dynamic vulcanization. The mixture was mixed and reacted at 220°C and 400 r / min for 5 min. The mixture was then granulated to obtain silicone-modified polyolefin elastomer.

[0060] Comparative Example 1

[0061] Referring to Example 1, the difference is that directional hydrogenated SEBS and silane-modified POE are not added;

[0062] Comparative Example 2

[0063] Refer to Example 1, except that silane-modified POE is not added;

[0064] Comparative Example 3

[0065] Referring to Example 1, the difference is that directional hydrogenated SEBS is not added.

[0066] The physical properties of the silicone-modified polyolefin elastomers obtained in the examples and comparative examples were tested and compiled into a table, as shown below.

[0067] Example Test Results

[0068] Test Project Example 1 Example 2 Example 3 Example 4 Hardness (A) 61 65 58 52 Hardness (A) (Model Prediction) 60.19 65.81 57.90 51.86 Tensile strength (MPa) 16 22 12 10 Elongation at break (%) 550 590 630 490 Tear strength (kN / m) 51 60 43 37 Compression permanent deformation (%) 18 20 21 23

[0069] Comparative test results

[0070] Test Project Comparative Example 1 Comparative Example 2 Comparative Example 3 Hardness (A) 64 63 63 Hardness (A) (Model Prediction) 60.19 60.19 60.19 Tensile strength (MPa) 6 10 8 Elongation at break (%) 223 350 330 Tear strength (kN / m) 19 25 20 Compression permanent deformation (%) 39 28 32

[0071] By comparing the hardness test results and model prediction results of the examples, the difference between the two is within 1A, indicating that the model of the present invention can make relatively accurate predictions of hardness. In Comparative Examples 1-3, the hardness prediction model deviation is greater than 2A, and the worse the compatibility, the greater the deviation. By comparing Example 1 and Comparative Example 1, under the same process conditions, without the addition of directional hydrogenated SEBS and silane-modified POE, the physical property test results of Comparative Example 1 are significantly worse, and compared with the smooth feel of Example 1, the sample of Comparative Example 1 feels rougher. Comparative Example 2 only added periodically hydrogenated SEBS, and the physical properties and feel were slightly improved compared with Comparative Example 1, but the problem of poor compatibility still exists. Compared with Example 1, both physical properties and feel are worse. Comparative Example 3 only added silane-modified POE, and compared with Example 1, the problem of poor compatibility still exists, and the physical properties and feel are not as good. By comparing Example 1 and Comparative Examples 1-3, it can be found that adding directional hydrogenated SEBS or silane-modified POE alone cannot form a dual-step compatibility mechanism, and the physical properties are not as effective as when they are added together.

[0072] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A silicone-modified polyolefin elastomer material, comprising the following raw materials in parts by weight: 30-50 parts SEBS, 20-35 parts POE, 3-8 parts directional hydrogenated SEBS, 1.5-5 parts silane-modified POE, 20-40 parts methyl vinyl silica gel, 1.2-2.5 parts crosslinking agent, and 1-10 parts filler.

2. The silicone-modified polyolefin elastomer material according to claim 1, wherein, The SEBS has a styrene content of 10-35% by mass, a melt index of 0.1-10 g / 10 min (200℃ / 5 kg), preferably 0.2-8 g / 10 min (200℃ / 5 kg), and a hardness range of 40-60A.

3. The silicone-modified polyolefin elastomer material according to claim 1, wherein, The styrene content of the directed hydrogenated SEBS is 15-50% by mass, and the melt index is 0.5-10 g / 10 min (200℃ / 5 kg), preferably 0.5-5 g / 10 min (200℃ / 5 kg).

4. The silicone-modified polyolefin elastomer material according to claim 1, wherein, The POE has a melt flow index of 1-20 g / 10 min (190℃ / 2.16 kg), preferably 1-10 g / 10 min (190℃ / 2.16 kg); and a hardness range of 60-85A.

5. The silicone-modified polyolefin elastomer material according to claim 1, wherein, The modifier for the silane-modified POE is selected from one or more of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(β-methoxyethoxy)silane, γ-methacryloyloxypropyltrimethoxysilane, and γ-glycidoxypropyltrimethoxysilane, and the grafting rate of the modifier is preferably 1-5 wt%.

6. The silicone-modified polyolefin elastomer material according to claim 1, wherein, The methyl vinyl silica gel is selected from vinyl-terminated or methyl-terminated types, with a vinyl molar content of 0.03-1%, preferably 0.03-0.2%, and a molecular weight of 450,000-1,200,000.

7. The silicone-modified polyolefin elastomer material according to claim 1, wherein, The crosslinking agent is a hydrogen-containing silicone oil, selected from one or more of end-containing hydrogen-containing silicone oil, side-containing hydrogen-containing silicone oil, and end-side hydrogen-containing silicone oil, with a hydrogen content of 0.01-2 wt%, preferably 0.5-1.6%.

8. The silicone-modified polyolefin elastomer material according to claim 1, wherein, The filler is selected from one or more of silica, talc, and antioxidants (e.g., 1010, 1135, 168).

9. The dynamic vulcanization preparation method of the silicone-modified polyolefin elastomer material according to any one of claims 1-8, comprising the following steps: (1) Premixing: Add the raw materials to a kneader or internal mixer and mix them, and then extrude and granulate them through an extruder; (2) Dynamic vulcanization: The product obtained in step (1) is mixed with the catalyst through a mixer and added to a twin-screw extruder for dynamic vulcanization reaction, and granulated to obtain silicone-modified polyolefin elastomer.

10. The method according to claim 9, wherein, The temperature for premixing in step (1) is 170-210℃ and the mixing time is 5-20 min; the temperature for dynamic vulcanization in step (2) is 180-220℃ and the dynamic vulcanization time is 1-10 min.

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