Low-temperature-resistant skin-friendly TPV (thermoplastic vulcanizate) material and preparation method and application thereof
By optimizing the composition and processing technology of TPV materials, a low-temperature resistant and skin-friendly TPV material was prepared, which solved the problem of insufficient low-temperature and oil resistance of existing TPV materials, and enabled its application in automotive engine seals, especially improving sealing stability and feel in cold regions.
Patent Information
- Application Number
- CN202511670732.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-14
- Publication Date
- 2026-02-24
AI Technical Summary
The application of existing PP+EPDM system TPV materials in automotive parts is limited, mainly due to insufficient low-temperature resistance, poor oil resistance, and high sliding friction coefficient, resulting in poor slip and feel. In particular, there are sealing stability issues in cold regions and engine sealing applications.
Using raw materials such as PP resin, COC resin, silica, talc, EPDM adhesive, methyl vinyl phenyl silicone rubber, vulcanizing agent, processing aids and carbon black masterbatch, low-temperature resistant and skin-friendly TPV material is prepared by melt mixing in a twin-screw extruder. The material composition and processing technology are optimized to improve low-temperature resistance, oil resistance and low sliding friction coefficient.
A TPV material with no cracks at -70℃, no stickiness at 150℃, and a low coefficient of sliding friction has been developed. It is suitable for automotive engine sealing, improving the material's low-temperature resistance and slip properties, and meeting the application needs of cold regions.
Smart Images
Figure CN121554880A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of new materials technology and relates to automotive materials, specifically a low-temperature resistant, skin-friendly TPV material, its preparation method, and its application. Background Technology
[0002] Currently, automotive seals primarily utilize soft PVC, EPDM, and PP+EPDM dynamically vulcanized elastomer (TPV) materials. PVC and EPDM rubber are gradually being replaced by TPV materials due to environmental concerns, particularly in static sealing systems. PP+EPDM TPV materials are widely used in automotive static sealing components due to their ease of processing and recyclability. However, their limited low-temperature resistance and insufficient oil resistance (especially fuel resistance), along with high surface sliding friction coefficient and insufficient friction resistance (leading to balling and excessive material buildup) and poor slip properties, restrict their application in automotive parts requiring high oil resistance, low-temperature resistance, and low friction coefficients, especially in cold northern regions. Summary of the Invention
[0003] Currently, PP+EPDM system TPV materials have insufficient fuel resistance and low-temperature resistance, with a low-temperature embrittlement temperature of around -45℃, resulting in a low-temperature operating temperature generally not exceeding -20℃. In particular, the high coefficient of sliding friction in PP+EPDM system TPV materials leads to poor slipperiness and feel, and the surface is prone to stickiness, especially for low-hardness materials (hardness below 60A). This invention discloses a low-temperature resistant, skin-friendly TPV material, its preparation method, and its applications, achieving good fuel resistance, especially good low-temperature performance, and providing a smooth and pleasant feel.
[0004] The present invention adopts the following technical solution.
[0005] A low-temperature resistant, skin-friendly TPV material is prepared from raw materials including PP resin, COC resin, silica, talc, EPDM adhesive, methyl vinyl phenyl silicone rubber, vulcanizing agent, processing aids, and carbon black masterbatch.
[0006] This invention discloses a method for preparing the aforementioned low-temperature resistant, skin-friendly TPV material, comprising the following steps: melt-mixing raw materials including PP resin, COC resin, silica, talc, EPDM adhesive, methyl vinyl phenyl silicone rubber, vulcanizing agent, processing aids, and carbon black masterbatch, preferably using a twin-screw extruder to obtain the low-temperature resistant, skin-friendly TPV material. For example, the diameter of the twin-screw extruder can be 30-75 mm, the rotation speed can be 300-1200 rpm, and the temperature can be 170-230°C, followed by processing, molding, and granulation.
[0007] In this invention, the vulcanizing agent includes a peroxide vulcanizing agent and BMI (N,N'-4,4'-diphenylmethane bismaleimide), wherein the peroxide vulcanizing agent can be selected from bis(2,4'-diphenylmethane) and odorless DCP, etc. Preferably, the mass ratio of peroxide vulcanizing agent to BMI is (0.5-1.5):1; more preferably, the mass ratio of peroxide vulcanizing agent to BMI is (0.7-1.2):1.
[0008] In this invention, the processing aids include one or more of antioxidants, UV stabilizers, lubricants, initiators, and anti-aging agents.
[0009] In this invention, the mass ratio of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica is (3-15):(5-20):(30-45):(20-40):(2-8):(5-15). Preferably, the mass ratio of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica is (5-10):(7-15):(35-42):(25-35):(3-7):(8-12).
[0010] In this invention, the total mass of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica is 100%, and the mass of the vulcanizing agent is 1.5-3%, that is, the amount of vulcanizing agent is 1.5-3% of the total mass of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica; preferably 1.7-2.5%.
[0011] In this invention, the total mass of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica is 100%, and the mass of processing aids is 1.5-3%, that is, the amount of processing aids is 1.5-3% of the total mass of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica; preferably 1.7-2.5%.
[0012] In this invention, the total mass of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica is 100%, and the mass of carbon black masterbatch is 1.5-3%, that is, the amount of carbon black masterbatch is 1.5-3% of the total mass of PP resin, COC resin, EPDM adhesive, methyl vinyl phenyl silicone rubber, talc, and silica; preferably 1.7-2.5%.
[0013] This invention discloses the application of the above-mentioned low-temperature resistant, skin-friendly TPV material in the preparation of sealing components; or the application of the above-mentioned low-temperature resistant, skin-friendly TPV material in the preparation of automotive sealing materials, especially automotive engine sealing materials.
[0014] An automotive sealing material comprising the aforementioned low-temperature resistant, skin-friendly TPV material. Preferably, the automotive sealing material is an automotive engine sealing material.
[0015] Currently, PP+EPDM system TPV materials are used in the automotive field, mainly for static sealing components. The main problems with their application in automotive engine peripheral products are insufficient fuel resistance, poor low-temperature resistance, high surface sliding friction coefficient leading to insufficient friction resistance (easily causing balling and excessive material debris), and insufficient slippage. In particular, the poor heat-adhesion resistance, which has received little attention, affects sealing stability. Currently, industry professionals focus on the retention rate of mechanical properties after TPV heat treatment to assess the material's heat aging resistance, but no information has been found regarding the stickiness of TPV material surfaces during heating. The applicant has for the first time disclosed a low-temperature resistant, skin-friendly TPV material, solving the problem of surface stickiness even in existing TPV materials with good heat aging resistance. Specifically, after heat treatment at 150℃ for 180 minutes, the surface of this invention's low-temperature resistant, skin-friendly TPV material is not sticky, a technological advancement beyond expectations. Moreover, it simultaneously possesses the advantages of a low surface sliding friction coefficient, good friction resistance, and sufficient slippage. Importantly, it exhibits excellent low-temperature resistance, showing no cracks upon drop ball impact at -70℃, achieving unexpected technical results. Attached Figure Description
[0016] Figure 1 Photographs of extruded test pieces according to embodiments of the present invention.
[0017] Figure 2 This is a photo of the oil that seeps out after the sample is heated.
[0018] Figure 3 This is a photograph of the test piece of the present invention, showing that no oil was produced after heating and the markings were clear.
[0019] Figure 4 This is a photograph of the test piece of the present invention that does not produce oil after heating. Detailed Implementation
[0020] Currently, PP+EPDM system TPV materials are mainly used for static sealing components in automobiles, with few reports of their application in engine sealing. Automotive engines frequently operate under unsteady transitional conditions, such as starting, warm-up, sudden acceleration, and sudden deceleration. Especially under sudden acceleration conditions, the unsteady temperature of the engine cylinder head can reach over 150℃. Existing TPV materials may exhibit surface stickiness, which, over time, reduces their sealing stability. Furthermore, insufficient oil resistance is also a limiting factor in the application of TPV materials in engine sealing, and this is a key issue that needs to be addressed. Simultaneously, for cold regions, low-temperature resistance is also crucial. Currently, TPV materials that do not crack at -40℃ ensure their application in cold regions. The industry has proposed even more stringent testing conditions at -70℃; if the material does not crack at this temperature, its stability in cold regions can be guaranteed.
[0021] The applicant previously disclosed a heat-resistant aging-resistant EPDM dynamically vulcanized TPV, its preparation method, and its application. The method involves feeding a masterbatch into a twin-screw extruder for vulcanization; then feeding COC resin into the twin-screw extruder from the middle section for mixing; followed by homogenization; and finally granulation to obtain the heat-resistant aging-resistant EPDM dynamically vulcanized TPV. The applicant also previously disclosed a low-sliding-friction coefficient self-lubricating TPV material, its preparation method, and its application. This method involves melt-mixing a TPV base material, additives, and auxiliaries to obtain a low-sliding-friction coefficient self-lubricating TPV material; the additives are polyethylene, phenyl silicone rubber, and molybdenum disulfide. These products exhibit excellent heat aging resistance or wear resistance, but poor oil resistance, and in particular, poor anti-heat-sticking properties have been observed in applications.
[0022] This invention involves blending PP resin, COC resin, EPDM rubber, methyl vinyl phenyl silicone rubber, talc, silica, and processing aids in a Banbury mixer to prepare a masterbatch. Then, the masterbatch, vulcanizing agent, and carbon black masterbatch are vulcanized and granulated in a twin-screw extruder to prepare a novel dynamically vulcanized TPV material, which is a low-temperature resistant, skin-friendly, and tactile TPV material. The Banbury mixer can be a 5-100L unit, with a blending temperature of 190℃-210℃. The diameter of the twin-screw extruder can be 30-75mm, the melt processing speed can be 300-1200rpm, and the temperature can be 170-230℃, for example: feed section: 170-190℃, melt section: 190-220℃, mixing section: 210-230℃, die head section: 200-220℃, and main extruder speed: 500-600rpm. The specific feeding and extrusion operations are conventional techniques.
[0023] In this invention, the PP resin is homopolymer polypropylene with a melt index of 1-4 g / 10 min; the COC resin is a cyclic olefin copolymer with a glass transition temperature above 149°C and a melt index of less than 10 g / 10 min; the silica is prepared by precipitation method with a particle size of 1000 mesh; the talc powder is 2500 mesh; and the methyl vinyl phenyl silicone rubber has a molecular weight of 650,000 and a phenyl content of less than 10%.
[0024] Appearance and performance evaluation. The appearance of the extruded specimens (1mm thickness, 15mm width) was evaluated using standard methods. Observe the appearance: it should be delicate and free of grains; Shore hardness: According to ISO 868, reading at 15s, Shore A, required to be 50A-60A; Tensile strength: According to ISO 37, 500 mm / min, the requirement is above 4.5 MPa; Heat aging resistance: According to ISO 188, 168h@150℃, the tensile strength retention rate should be above 70%; Low temperature resistance: Low temperature drop ball impact test at -70℃, 5J energy (500g steel ball, 1m height), no cracks required (OK), otherwise NG; some test pieces were first tested at -50℃, and if cracks were found, they were not tested again; Oil resistance: According to ASTM D471, 903# oil, after 72 hours, the weight change rate should not exceed 50%; Smoothness: According to GB / T 10006 standard, at 9.8N, the coefficient of sliding friction should not exceed 0.7; Oiliness and stickiness: Stack two test pieces together and clamp the four sides with a dovetail clip, bake at 150℃ for 180 minutes. After opening, there should be no oiliness or stickiness, the surface should still be relatively dry, the glass rod should be smooth and without any stickiness, and the oily marks should be almost impossible to wipe off (wipe with a tissue once).
[0025] The raw materials used in this invention are existing products, and the specific preparation operations and performance testing are conventional techniques.
[0026] PP resin: homopolymer polypropylene, melt index 2g / 10min (Sinopec K8003); COC resin: Cyclic olefin copolymer, glass transition temperature above 149℃, melt index within 10g / 10min (TAMT1410 from Topene Technology). Silica: Precipitation method, particle size 1000 mesh, Shengda Chemical; Talc powder: 2500 mesh, Heshan Chemical; EPDM adhesive: Keltan 5469C; Methyl vinyl phenyl silicone rubber: molecular weight 650,000, phenyl content less than 10% (Anhui Yueta IOTA 3120); Methyl vinyl silicone rubber (110-3); Vulcanizing agent: BMI + 225, with a mass ratio of 1:0.9; Processing aids include antioxidants, UV stabilizers, and lubricants, all of which are commercially available: antioxidant 1010, UV stabilizer 622, and lubricant erucamide.
[0027] The charcoal black masterbatch is Cabot 2014.
[0028] The preparation method of the low-temperature resistant, skin-friendly TPV material of the present invention is a conventional technique. First, all materials except vulcanizing agent and color masterbatch are prepared into masterbatch in a mixer. Then, the masterbatch, vulcanizing agent and color masterbatch are vulcanized and granulated in a twin-screw extruder to prepare a novel dynamically vulcanized TPV material.
[0029] Examples & Comparative Examples Table 1. Examples and comparative formulations (Kg) and extrusion test results.
[0030] The mass ratio of antioxidant, UV protectant, and lubricant is 0.3:0.3:0.1.
[0031] Comparative Example 8 Referring to Example 1, methyl vinyl silicone rubber was used instead of methyl vinyl phenyl silicone rubber, while the rest remained the same. The prepared test piece showed no cracks when dropped at -50°C, but cracks appeared when dropped at -70°C, and slight oiling and stickiness occurred after 180 minutes at 150°C.
[0032] Comparative Example 9 Referring to Example 1, the vulcanizing agent was replaced with a noble metal catalytic system: methyl-terminated hydrogen-containing silicone oil with a hydrogen content of 0.80 wt% (3 kg) and a chloroplatinic acid-vinyltetramethylsiloxane complex solution (concentration 2000 ppm, amount 650 g based on platinum content). The prepared test piece showed cracks when dropped at -50°C, and exhibited oil seepage and stickiness after 180 minutes at 150°C. These obvious phenomena were observed. See [link to example]. Figure 2 The oily ink marks show signs of erasure.
[0033] Preparation methods for the examples and comparative examples: PP resin, COC resin, EPDM rubber, silicone rubber, talc, silica, and processing aids (raw materials selected according to Table 1) were blended in an internal mixer to prepare a masterbatch; then, the masterbatch, vulcanizing agent, and carbon black masterbatch were vulcanized and granulated in a twin-screw extruder to prepare a novel dynamically vulcanized TPV material, which is a low-temperature resistant, skin-friendly, and hand-feeling TPV material. The internal mixer was a 50L unit, the blending temperature was 200℃, and the time was 1 hour; the twin-screw extruder used had a diameter of 55mm, a melt processing speed of 600rpm, and the following temperatures were set: feed section: 170–190℃, melt section: 190–220℃, mixing section: 210–230℃, and die head section: 200–220℃.
[0034] Except for Comparative Example 3, the other comparative examples exhibited varying degrees of oiliness and stickiness; moreover, marks made with an oil-based pen before heating to 150°C were clearly visible, but after heating, the marks were easily erased after a single wipe with a tissue. In contrast, the extrusion test specimens of the formulations in Examples 1, 2, and 4 of this invention can be found in the photographs. Figure 1 From left to right, these correspond to Examples 1, 2, and 4. Before heating to 150°C, marks were made with an oil-based pen; the marks were clearly visible. After heating, the marks remained visible even after wiping with a tissue once, showing almost no signs of removal. Furthermore, no oily or sticky residue appeared after heating to 150°C. Figure 3 This is a photo of the product from Example 1 after heating; the markings are still clearly visible. Figure 4 The photo shows the specimen of Example 4 after being heated to 150°C. The surface remained smooth and there was no oil seepage.
[0035] Comparison Example Currently, commercially available TPV products claiming to have good oil resistance show cracking after a drop ball test at -50°C, and exhibit oil seepage and stickiness after 180 minutes at 150°C. Even the commercially available TPV product with the best (nominal) heat aging resistance shows cracking after a drop ball test at -70°C, and slight oil seepage and stickiness after 180 minutes at 150°C. This is why existing commercially available products are difficult to apply to automotive engine sealing, especially for automotive engine sealing in extremely cold regions.
[0036] The applicant previously disclosed a low sliding friction coefficient self-lubricating TPV material with a delicate and smooth appearance, low surface energy, good high temperature resistance, low sliding friction coefficient and self-lubricating properties, which improves friction resistance and durability of sealing strip products; however, it developed cracks when dropped at -70℃ and showed slight oil seepage and stickiness after 180 minutes at 150℃.
[0037] This invention achieves good oil resistance and excellent low-temperature performance, and also provides a good feel and low coefficient of sliding friction at room temperature; in particular, it does not produce oil or become sticky when heated.
Claims
1. A low-temperature resistant, skin-friendly TPV material, characterized in that, The raw materials for preparing low-temperature resistant, skin-friendly TPV materials include PP resin, COC resin, silica, talc, EPDM adhesive, methyl vinyl phenyl silicone rubber, vulcanizing agent, processing aids, and carbon black masterbatch.
2. The low-temperature resistant, skin-friendly TPV material according to claim 1, characterized in that, The mass ratio of PP resin, COC resin, EPDM glue, methyl vinyl phenyl silicone rubber, talc powder, and silica is (3-15): (5-20): (30-45): (20-40): (2-8): (5-15).
3. The low-temperature resistant, skin-friendly TPV material according to claim 2, characterized in that, The mass ratio of PP resin, COC resin, EPDM glue, methyl vinyl phenyl silicone rubber, talc powder, and silica is (5-10): (7-15): (35-42): (25-35): (3-7): (8-12).
4. The low-temperature resistant, skin-friendly TPV material according to claim 1, characterized in that, The mass of PP resin, COC resin, EPDM glue, methyl vinyl phenyl silicone rubber, talc, and silica is 100%; the mass of vulcanizing agent is 1.5-3%, the mass of processing aids is 1.5-3%, and the mass of carbon black masterbatch is 1.5-3%.
5. The preparation method of the low-temperature resistant, skin-friendly TPV material according to claim 1, characterized in that, The process includes the following steps: melting and mixing raw materials including PP resin, COC resin, silica, talc, EPDM adhesive, methyl vinyl phenyl silicone rubber, vulcanizing agent, processing aids, and carbon black masterbatch to obtain a low-temperature resistant, skin-friendly TPV material.
6. The method for preparing the low-temperature resistant, skin-friendly TPV material according to claim 5, characterized in that, Vulcanizing agents include peroxide vulcanizing agents and BMI; processing aids include one or more of antioxidants, UV stabilizers, lubricants, initiators, and antioxidants.
7. The application of the low-temperature resistant, skin-friendly TPV material of claim 1 in the preparation of sealing components.
8. The application of the low-temperature resistant, skin-friendly TPV material of claim 1 in the preparation of automotive sealing materials.
9. An automotive sealing material comprising the aforementioned low-temperature resistant, skin-friendly TPV material.
10. The application according to claim 7 or the automotive sealing material according to claim 9, characterized in that, Automotive sealing materials are the sealing materials for automotive engines.