High and low temperature resistant formed rubber plug, sealing rubber plug and preparation method thereof

Abstract

The application discloses a high and low temperature resistant cured rubber plug, a sealing rubber plug and a preparation method thereof, which is composed of the following components in percentage by mass: ethylene-propylene-diene monomer (EPDM), polypropylene (PP), alkane oil, styrene elastomer, talcum powder, calcium carbonate, polyethylene (PE), ultraviolet absorber UV329, black pigment, and the balance of zinc oxide; the application adopts an EPDM / PP / elastomer composite matrix, cooperates with the alkane oil, inorganic fillers and weather-resistant additives to form a stable synergistic system, realizes the balance of elasticity and rigidity, and the product is not easy to be brittle broken and to be deformed and slipped; meanwhile, the product has excellent high and low temperature resistance, can maintain good toughness and rigidity in a low temperature environment of-40 DEG C without brittle breaking and cracking, is not softened and deformed in a high temperature environment of 120 DEG C, and has stable performance in a high and low temperature cycle environment, and can be adapted to severe use scenes such as cold regions, high temperature scenes and high and low temperature alternating scenes.

Description

Technical Field

[0001] This invention belongs to the field of sealing component technology, and relates to a high and low temperature resistant forming rubber plug, a sealing rubber plug and its preparation method. Background Technology

[0002] Sealing plugs are widely used in various equipment assembly and fixing scenarios due to their advantages such as light weight, insulation, corrosion resistance, and low cost. Traditional sealing plugs are mostly made of single polypropylene (PP), polyethylene (PE), or ordinary rubber, which have obvious performance defects: single PP material has sufficient rigidity but insufficient toughness and elasticity, making it prone to brittle breakage during assembly and having poor impact resistance; single rubber material has excellent elasticity but low rigidity and hardness, resulting in insufficient fastening force and easy creep and slippage after long-term use; conventional blended materials have not been optimized for weather resistance, making them prone to aging, cracking, and fading under outdoor sunlight and high and low temperature cycling environments, resulting in a short service life; at the same time, the poor compatibility between resin and filler leads to poor processing fluidity and large fluctuations in mechanical properties, making it difficult to meet the requirements of high reliability and high weather resistance fasteners in new energy and other fields.

[0003] Currently, composite systems based on TPV, PP, and EPDM are the mainstream direction for improving the overall performance of sealing plugs. However, existing technologies generally suffer from problems such as unreasonable component ratios, low matching degree of weather-resistant additives, and incompatibility between preparation processes and formulations, making it difficult to achieve a balance between high elasticity, high rigidity, high weather resistance, and good processability at the same time. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high- and low-temperature resistant forming rubber stopper and sealing rubber stopper. By optimizing the synergistic ratio of the matrix resin, plasticizer, elastomer, inorganic filler, and weather-resistant additives, the material possesses excellent elasticity, rigidity, dimensional stability, and UV aging resistance. Another objective of this invention is to provide a continuous manufacturing method for the above-mentioned sealing rubber stopper, with a stable and controllable process suitable for industrial mass production, and the resulting product can meet the needs of various application scenarios.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A type of high and low temperature resistant forming rubber stopper and sealing rubber stopper, comprising the following components by mass percentage: Ethylene propylene diene monomer (EPDM) 32%~38%, polypropylene (PP) 13%~19%, alkane oil 28%~34%, styrene elastomer 3%~7%, talc 4%~8%, calcium carbonate 2%~6%, polyethylene (PE) 0.5%~1.5%, ultraviolet absorber UV-329 0.5%~1.5%, black pigment 0.5%~1.5%, with the balance being zinc oxide.

[0006] Among them, EPDM rubber and styrene-based elastomers work synergistically to provide high elasticity and toughness; polypropylene and polyethylene provide basic rigidity and processing fluidity; alkane oils act as plasticizers to improve the compatibility and plasticizing effect of each component; talc and calcium carbonate act as inorganic fillers to improve hardness, dimensional stability and heat resistance; UV absorber UV-329 significantly improves UV aging resistance; zinc oxide acts as an activator to optimize the rubber phase interface; and black pigments ensure uniform and stable appearance.

[0007] The preparation method of the above-mentioned high weather-resistant TPV / PP composite sealing plug includes the following steps: Step S1: Raw material pretreatment: Dry EPDM rubber, styrene elastomer, polypropylene, and polyethylene at room temperature to remove moisture; dry talc powder and calcium carbonate at 100~110℃ for 2~3 hours, then pulverize and pass through a 200-mesh sieve for later use. Step S2: Internal mixing and blending: Add EPDM rubber and styrene elastomer to an internal mixer and mix at 150~160℃ for 5~8 minutes. Then add polypropylene, polyethylene, and alkane oil and continue mixing for 10~15 minutes. Next, add UV absorber UV-329, zinc oxide, and black pigment and mix for 3~5 minutes. Finally, add talc and calcium carbonate and mix for 5~10 minutes. The speed of the internal mixer is controlled at 300~500 r / min to obtain a uniform blend. Step S3: Extrusion granulation: The blend is added to a twin-screw extruder at an extrusion temperature of 160~180℃ and a screw speed of 200~300r / min. The composite particles are obtained by melt extrusion, water cooling and pelletizing. Step S4: Injection molding: Add the composite particles to the injection molding machine, with a barrel temperature of 170~190℃, a mold temperature of 40~60℃, an injection pressure of 80~100MPa, a holding pressure of 10~15s, and cooling and solidification to obtain a black TPV / PP composite sealing plug.

[0008] The beneficial effects of this invention are as follows: This invention uses an EPDM / PP / elastomer composite matrix, combined with alkane oil, inorganic fillers, and weather-resistant additives to form a stable and synergistic system, achieving a balance between elasticity and rigidity. The product is not easily brittle or prone to deformation and slippage; and it utilizes UV absorbers... 329 constructs a highly efficient weather-resistant system with excellent outdoor aging resistance and significantly extended service life. It also possesses excellent high and low temperature resistance, maintaining good toughness and rigidity at -40℃ without brittle fracture or cracking, and showing no softening or deformation at 120℃. It exhibits stable performance in high and low temperature cycling environments, making it suitable for harsh applications in cold regions, high-temperature scenarios, and alternating high and low temperatures. The scientifically proportioned components ensure good interfacial compatibility, excellent processing fluidity, and continuous and stable injection molding with a high finished product qualification rate. The formula can be flexibly adjusted within a protected range to meet the needs of different scenarios, such as standard, high-elasticity, high-rigidity, and ultra-high weather resistance types. The overall solution has excellent practicality, stability, and industrialization prospects. Detailed Implementation

[0009] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only for illustrating the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Simple modifications and equivalent substitutions made by those skilled in the art within the scope of the present invention are all within the scope of protection of the present invention. The embodiments of the present invention adopt a continuous and unified preparation process, with only minor adjustments to the proportions and process parameters according to performance requirements. The overall process is consistent and highly reproducible.

[0010] Example 1: The preferred embodiment of this invention comprises, by weight percentage: 35% EPDM rubber, 16% polypropylene, 31% alkane oil, 5% styrene elastomer, 6% talc, 4% calcium carbonate, 1% polyethylene, and UV absorber. 3291%, black pigment 1%, balance zinc oxide; In the preparation process, EPDM rubber, styrene elastomer, polypropylene, and polyethylene are first air-dried at room temperature to remove moisture. Simultaneously, talc powder and calcium carbonate are dried at 105℃ for 2.5 hours and then pulverized through a 200-mesh sieve. Subsequently, EPDM rubber and styrene elastomer are added to an internal mixer and mixed at 155℃ for 6 minutes. Polypropylene, polyethylene, and alkane oil are then added, and the mixing continues for 12 minutes. Finally, UV absorber is added. 329. Zinc oxide and black pigment are mixed for 4 minutes. Finally, talc powder and calcium carbonate are added and mixed for 8 minutes. The speed of the mixer is maintained at 400 r / min. After obtaining a uniform blend, it is fed into a twin-screw extruder. After melt extrusion, water cooling, and pelletizing, composite particles are obtained. The composite particles are then added to an injection molding machine. The barrel temperature is set to 180℃, the mold temperature to 50℃, the injection pressure to 90MPa, and the holding time to 12s. After cooling and shaping, high and low temperature resistant chemically formed rubber stoppers and sealing rubber stoppers are obtained. Testing revealed that the sealing plug exhibits a tensile strength of 18.2 MPa, an elongation at break of 320%, and a Shore A hardness of 85. After 1000 hours of UV aging, it showed no cracking, powdering, or significant discoloration. After 168 hours of heat aging at 100℃, it retained ≥90% of its mechanical properties. It showed no brittle fracture or cracking at -40℃ and no softening or deformation at 120℃. It maintains excellent resilience and toughness, with no performance degradation after high and low temperature cycling. It combines balanced rigidity, elasticity, weather resistance, and processing stability, making it suitable for most conventional fastening applications in new energy, electronics, and hardware industries. This makes it the most suitable basic solution for large-scale mass production.

[0011] Example 2: Based on the continuous process of Example 1, the formulation was adjusted to obtain the high and low temperature resistant rubber stopper and sealing rubber stopper of Example 2, which, by mass percentage, consisted of: 37% EPDM rubber, 14% polypropylene, 32% alkane oil, 6% styrene elastomer, 5% talc, 3% calcium carbonate, 0.8% polyethylene, and UV absorber. 3291%, black pigment 1%, balance zinc oxide; The raw material pretreatment steps are exactly the same as in Example 1. During the mixing stage, the temperature is controlled at 150-155℃ and the rubber plasticizing time is extended to 8 minutes. During the extrusion stage, the temperature is set at 165-175℃ and the screw speed is 240 r / min. During the injection molding stage, the pressure is reduced to 85 MPa and the holding time is shortened to 10 seconds. By increasing the ratio of rubber to elastomer and optimizing the plasticizing and molding parameters, the toughness and resilience of the material are enhanced. The prepared sealing plug has a tensile strength of 16.5 MPa, an elongation at break of 360%, a Shore A hardness of 80, and a resilience of ≥65%. It still maintains its good appearance after 1000 hours of UV aging. Compared with Example 1, its elasticity is improved by about 12.5%, and its torsional and impact resistance is better. It is suitable for applications that require frequent disassembly and assembly and have shock absorption and cushioning requirements. Although the mechanical strength is slightly reduced, it fully meets the usage requirements and complements the performance of Example 1.

[0012] Example 3: Continuing the above continuous preparation logic, the formula and process were adjusted to obtain the high-rigidity sealing plug of Example 3, which, by mass percentage, consisted of: 33% EPDM rubber, 18% polypropylene, 29% alkane oil, 4% styrene elastomer, 7% talc, 5% calcium carbonate, 1.2% polyethylene, and UV absorber. 3291%, black pigment 1%, balance zinc oxide; The raw material pretreatment remains unchanged. During the mixing stage, the temperature is increased to 155-160℃ and the mixing time of the filler is extended to 10 minutes. During the extrusion stage, the temperature is increased to 170-180℃ to enhance the system compatibility and material density. During the injection molding stage, the pressure is increased to 95MPa and the holding time is extended to 15s. By increasing the ratio of polypropylene to inorganic fillers, strengthening the blending and injection molding conditions, the rigidity and dimensional stability of the material are improved. The resulting sealing plug has a tensile strength of 20.5 MPa, an elongation at break of 280%, a Shore A hardness of 90, and a dimensional deviation of ±0.015 mm. Its creep performance is significantly better than that of conventional sealing plugs. Compared with Example 1, the tensile strength is increased by 12.6% and the hardness is increased by 5 degrees. It has a stronger fastening force and is not easy to deform or slip off. It is suitable for high-load, long-term fixed and high-precision assembly applications. It maximizes rigidity and stability with a slight decrease in toughness.

[0013] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high and low temperature resistant forming rubber stopper and sealing rubber stopper, characterized in that, Composed of the following components by weight percentage: 32%~38% EPDM rubber, 13%~19% polypropylene, 28%~34% alkane oil, 3%~7% styrene elastomer, 4%~8% talc, 2%~6% calcium carbonate, 0.5%~1.5% polyethylene, and UV absorber. 3290.5%~1.5%, black pigment 0.5%~1.5%, balance zinc oxide.

2. The high and low temperature resistant rubber stopper, sealing rubber stopper, and its preparation method according to claim 1, characterized in that, Its optimal formulation, by weight percentage, is: 35% EPDM rubber, 16% polypropylene, 31% alkane oil, 5% styrene elastomer, 6% talc, 4% calcium carbonate, 1% polyethylene, and UV absorber. 3291%, pigment 1%, balance zinc oxide.

3. The high and low temperature resistant forming rubber stopper and sealing rubber stopper according to claim 1, characterized in that, The sealing plug is black, and the substrate is a TPV / PP / EPDM composite system.

4. A high and low temperature resistant forming rubber stopper, a sealing rubber stopper, and a method for preparing the same, used in the preparation of the high and low temperature resistant forming rubber stopper and the sealing rubber stopper as described in any one of claims 1 to 3, characterized in that, Includes the following steps: Step S1: Raw material pretreatment: Dry EPDM rubber, styrene elastomer, polypropylene, and polyethylene at room temperature to remove moisture; Talc and calcium carbonate are dried at 100-110℃ for 2-3 hours and then passed through a 200-mesh sieve. Step S2: Internal mixing and blending: Internally mix EPDM rubber and styrene elastomer at 150-160℃ for 5-8 minutes, add polypropylene, polyethylene, and alkane oil and internally mix for 10-15 minutes, then add UV absorber.

329. Zinc oxide and pigment are mixed for 3-5 minutes, then talc and calcium carbonate are added and mixed for 5-10 minutes at a speed of 300-500 r / min. Step S3: Extrusion granulation: Twin-screw extruder temperature 160~180℃, screw speed 200~300r / min, extrusion, water cooling, pelletizing; Step S4: Injection molding: Barrel temperature 170~190℃, mold temperature 40~60℃, injection pressure 80~100MPa, holding pressure 10~15s, cooling and shaping.

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