Full-sea-depth adaptive long-life rubber material and manufacturing method thereof

Abstract

The invention discloses a rubber composite material for a watertight connector, and aims to provide a full-sea-depth adaptive long-life rubber material which is good in heat resistance and weather resistance, can reduce the vulcanization temperature and shorten the vulcanization time in the vulcanization process, and can improve the processing plasticity of a rubber material and the dimensional stability of a semi-finished product, and a manufacturing method of the full-sea-depth adaptive long-life rubber material. According to the key points of the technical scheme, ethylene propylene diene monomer with excellent heat resistance and weather resistance and chloroprene rubber are used together, peroxide is used as a vulcanizing agent, and a small-molecule vinyl-terminated polyfunctional group monomer is used as an auxiliary cross-linking agent, so that the heat resistance and weather resistance of the rubber can be further improved through the structure, and the service life of the rubber is prolonged. And ordered crystallization of a 1, 2 structure chain end on a chloroprene rubber molecular chain can be inhibited by destroying the regularity of the molecular chain through complex crosslinking. The method is suitable for the field of rubber composite material manufacturing.

Description

Technical Field

[0001] The present invention relates to a rubber composite material for a watertight connector, and more particularly to a rubber material with full ocean depth adaptability and long service life and a manufacturing method thereof. Background Art

[0002] Compared to natural rubber and general-purpose synthetic rubber, chloroprene rubber is widely used for sealing components in marine equipment due to its superior overall performance. The performance advantages of chloroprene rubber in marine environments include high adhesion, resistance to seawater corrosion, resistance to ozone and light-heat aging, heat resistance, and high mechanical properties. In watertight connectors, chloroprene rubber is widely used as an insulator in plugs and sockets, providing isolation and insulation between pins and sockets, while also providing a sealing effect through adhesion to the surfaces of pins and sockets. Furthermore, chloroprene rubber can achieve end-face sealing by compressing the end faces of the plug and socket after docking, preventing seawater intrusion.

[0003] While chloroprene rubber offers numerous performance advantages for marine applications, the design of chloroprene rubber composites for specific watertight connector applications still faces several challenges: 1) To preserve chloroprene rubber's excellent heat and weather resistance, chloroprene rubber is typically not cured using a sulfur cure system, but rather using oxide or peroxide cure systems. This type of cure system typically requires high-temperature vulcanization, which can cause thermal aging effects on other components connected to the insulator, such as wiring harnesses and cable sheaths. Switching to low-temperature vulcanization significantly prolongs the cure time. 2) Due to the predominance of the trans-1,4 structure and the high regularity of the molecular chain, most chloroprene rubber varieties have a strong tendency to crystallize. Rapid crystallization is beneficial for chloroprene rubber adhesives, but for products used in sealing applications, once crystallization occurs, the seal will significantly harden and the sealing surface contact will be poor, posing a risk of leaks. 3) Due to the presence of polar functional groups, the cohesive energy of the chloroprene rubber molecular chain is relatively high, the plasticity and fluidity during high-temperature thermal processing are poor, and the shrinkage rate of the extruded and pressed rubber is large, which will have a relatively significant impact on the vulcanization molding and dimensional control of subsequent products. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a full-sea-depth adaptable long-life rubber material and its manufacturing method with good heat resistance and weather resistance, which can reduce the vulcanization temperature and shorten the vulcanization time during the vulcanization process, and can improve the processing plasticity of the rubber compound and the dimensional stability of the semi-finished product.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a full-sea-depth adaptable long-life rubber material, comprising the following materials: chloroprene rubber, EPDM rubber, carbon black, peroxide DCP, a vinyl-terminated multifunctional monomer, and a tackifying resin, wherein the chloroprene rubber is one of conventional sulfur-regulated, thiol-regulated, and mixed-regulated types; the carbon black is one of N550, N660, and N774; the vinyl-terminated multifunctional monomer is one of TAIC or TMPTA; and the tackifying resin is one of C5 resin, C9 resin, or coumarone resin.

[0006] The present invention is further configured as follows: the amount of each component in the rubber material is: chloroprene rubber and EPDM rubber are both recorded as 100 phr, carbon black is 40-60 phr, peroxide DCP is 2-5 phr, terminal vinyl multifunctional monomer is 2-4 phr, and tackifying resin is 2-10 phr.

[0007] Preferably, in the combined amount of chloroprene rubber and EPDM rubber in the rubber material, the EPDM rubber is 10-30 phr.

[0008] The present application also provides a method for manufacturing a full-sea-depth adaptable and long-life rubber material, comprising the following steps: S1, preparing raw materials of corresponding components according to the rubber material to be manufactured;

[0009] S2. Set the speed of the internal mixer to 40 rpm and the temperature of the mixing chamber to 70° C. Add chloroprene rubber and EPDM rubber into the internal mixer and mix for 1.5 min.

[0010] S3. After the chloroprene rubber and EPDM rubber are mixed, carbon black and tackifying resin are added into an internal mixer and mixed again for 3.5 min to obtain a masterbatch;

[0011] S4. Take out the masterbatch from the internal mixer, adjust the speed of the internal mixer to 20 rpm, the temperature of the mixing chamber to 50°C, put the masterbatch back into the internal mixer, and mix for 1 minute;

[0012] S5, adding half of the raw material components of peroxide DCP and half of the raw material components of the vinyl-terminated multifunctional monomer into an internal mixer, and mixing for 1.5 minutes;

[0013] S6. Add the remaining half of the peroxide DCP and the remaining general vinyl-terminated multifunctional monomer into the internal mixer, mix again for 1.5 minutes, and discharge the rubber to obtain the final rubber mix.

[0014] By adopting the above technical solution, the beneficial effects are as follows: 1. The present application adopts EPDM rubber with excellent heat resistance and weather resistance and chloroprene rubber for combined use, and adopts peroxide as a vulcanizing agent, and uses a small molecule terminal vinyl multifunctional monomer as an auxiliary cross-linking agent. Specifically, the use of EPDM rubber with no double bonds in the main chain can further improve the heat resistance and weather resistance of the chloroprene rubber system. When conventional oxides or trithiocyanate (TCY) are used to vulcanize chloroprene rubber, they can only rely on the active chlorine atoms in the allylic position on the 1, 2 structural units in the main chain of the rubber macromolecule. Since 1, The proportion of 2 structures in the main chain is only 1.5%, so the cross-linking density of the vulcanized rubber formed by the conventional vulcanization system is relatively low. For the system using peroxide or terminal vinyl multifunctional monomers, the chloroprene rubber has more effective active sites on the molecular chain during vulcanization. At the same time, the vinyl multifunctional monomers can have multiple reaction end groups and are easy to form multi-arm bridges, which makes it have a higher degree of cross-linking. The above structure can not only further increase the heat resistance and weather resistance of the rubber, but also destroy the regularity of the molecular chain through complex cross-linking to inhibit the orderly crystallization of the 1,2 structure chain ends on the chloroprene rubber molecular chain.

[0015] 2. Furthermore, the combined use of the EPDM rubber can inhibit the crystallization tendency of the chloroprene rubber to a certain extent, and the use of the vinyl-terminated multifunctional monomer can efficiently activate the vulcanization system, which can not only reduce the vulcanization temperature but also shorten the vulcanization time. At the same time, the addition of the EPDM rubber to the chloroprene rubber can improve the plasticity of the rubber during processing and the dimensional stability of the semi-finished product due to the low cohesive energy density of the EPDM rubber's non-functional group molecules.

[0016] 3. At the same time, the rubber material is based on the problems existing in the chloroprene rubber-based watertight connector sealing material, so that the present application can have low-temperature rapid vulcanization characteristics, resistance to low-temperature crystallization and excellent processing plasticity, thereby solving the process problems of vulcanization and molding of watertight connector plugs and socket insulators, and avoiding the problem of sealing failure caused by crystallization hardening. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a flowchart of a manufacturing method of a full-sea-depth adaptable long-life rubber material and a manufacturing method thereof according to an embodiment of the present invention; DETAILED DESCRIPTION

[0018] Reference Figure 1 The present invention further describes an embodiment of a long-life rubber material with full ocean depth adaptability and a method for manufacturing the same.

[0019] For ease of explanation, spatial relative terms such as "upper", "lower", "left", and "right" are used in the embodiments to illustrate the relationship between one element or feature shown in the figures and another element or feature. It should be understood that, in addition to the orientation shown in the figures, spatial terms are intended to include different orientations of the device in use or operation. For example, if the device in the figure is inverted, the element described as being "under" other elements or features will be positioned "above" other elements or features. Therefore, the exemplary term "under" can include both upper and lower orientations. The device can be positioned in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used here can be interpreted accordingly.

[0020] Moreover, relational terms such as “first” and “second” are merely used to distinguish one component from another having the same name, but do not necessarily require or imply any actual relationship or order between these components.

[0021] A full-sea-depth adaptable and long-life rubber material comprises the following materials: chloroprene rubber, EPDM rubber, carbon black, peroxide DCP, a vinyl-terminated multifunctional monomer, and a tackifying resin, wherein the chloroprene rubber is one of conventional sulfur-regulated, mercaptan-regulated, and mixed-regulated types; the carbon black is one of N550, N660, and N774; the vinyl-terminated multifunctional monomer is one of TAIC and TMPTA; and the tackifying resin is one of C5 resin, C9 resin, or coumarone resin.

[0022] The dosage of each component in the rubber material is as follows: chloroprene rubber and EPDM rubber are both 100 phr, carbon black is 40-60 phr, peroxide DCP is 2-5 phr, terminal vinyl multifunctional monomer is 2-4 phr, and tackifying resin is 2-10 phr.

[0023] Preferably, in the combined amount of chloroprene rubber and EPDM rubber in the rubber material, the EPDM rubber is 10-30 phr.

[0024] The present application also provides a method for manufacturing a full-sea-depth adaptable and long-life rubber material, comprising the following steps: S1, preparing raw materials of corresponding components according to the rubber material to be manufactured;

[0025] S2. Set the speed of the internal mixer to 40 rpm and the temperature of the mixing chamber to 70° C. Add chloroprene rubber and EPDM rubber into the internal mixer and mix for 1.5 min.

[0026] S3. After the chloroprene rubber and EPDM rubber are mixed, carbon black and tackifying resin are added into an internal mixer and mixed again for 3.5 min to obtain a masterbatch;

[0027] S4. Take out the masterbatch from the internal mixer, adjust the speed of the internal mixer to 20 rpm, the temperature of the mixing chamber to 50°C, put the masterbatch back into the internal mixer, and mix for 1 minute;

[0028] S5, adding half of the raw material components of peroxide DCP and half of the raw material components of the vinyl-terminated multifunctional monomer into an internal mixer, and mixing for 1.5 minutes;

[0029] S6. Add the remaining half of the peroxide DCP and the remaining general vinyl-terminated multifunctional monomer into the internal mixer, mix again for 1.5 minutes, and discharge the rubber to obtain the final rubber mix.

[0030] The present invention adopts EPDM rubber with excellent heat resistance and weather resistance and chloroprene rubber for combined use, and adopts peroxide as vulcanizing agent, and uses small molecule terminal vinyl multifunctional monomer as auxiliary crosslinking agent. Specifically, the use of EPDM rubber with no double bonds in the main chain can further improve the heat resistance and weather resistance of the chloroprene rubber system. When conventional oxides or trithiocyanate (TCY) are used to vulcanize chloroprene rubber, they can only rely on the active chlorine atoms in the allylic position on the 1,2 structural units in the main chain of the rubber macromolecule. Due to the proportion of 1,2 structural units in the main chain, the heat resistance and weather resistance of the chloroprene rubber system are improved. It is only 1.5%, so the crosslinking density of the vulcanized rubber formed by the conventional vulcanization system is relatively low. For the system using peroxide or terminal vinyl multifunctional monomers, the chloroprene rubber has more effective active sites on the molecular chain during vulcanization. At the same time, the vinyl multifunctional monomers can have multiple reaction end groups and are easy to form multi-arm bridges, which makes it have a higher degree of crosslinking. The above structure can not only further increase the heat resistance and weather resistance of the rubber, but also destroy the regularity of the molecular chain through complex crosslinking to inhibit the orderly crystallization of the 1,2 structure chain ends on the chloroprene rubber molecular chain.

[0031] Furthermore, the combined use of the EPDM rubber can inhibit the crystallization tendency of the chloroprene rubber to a certain extent, and the use of terminal vinyl multifunctional monomers can efficiently activate the vulcanization system, which can not only reduce the vulcanization temperature but also shorten the vulcanization time. At the same time, the addition of the EPDM rubber to the chloroprene rubber can improve the plasticity of the rubber during processing and the dimensional stability of the semi-finished product due to the low cohesive energy density of the EPDM rubber's non-functional group molecules and its use in the chloroprene rubber.

[0032] At the same time, the rubber material is based on the problems existing in the chloroprene rubber-based watertight connector sealing material, so that the present application can have low-temperature rapid vulcanization characteristics, resistance to low-temperature crystallization and excellent processing plasticity, thereby solving the process problems of vulcanization and molding of watertight connector plugs and socket insulators, and avoiding the problem of sealing failure caused by crystallization hardening.

[0033] Furthermore, in this application, in order to obtain the optimal composite material, multiple embodiments and comparative examples are provided to obtain multiple experimental effects, and the experimental results are shown in Table 1 below:

[0034]

[0035]

[0036] Table 1 - Rubber compound formula composition

[0037] The test conditions for the positive vulcanization time are 145℃×90min, with Tc90 as the positive vulcanization time. The vulcanized rubber physical property test samples are vulcanized and molded at 145℃×Tc90.

[0038] The shrinkage rate of the film is based on the final mixing of the rubber on an open mixing mill at 50°C. The thickness of the film is 3.0-3.5mm. This temperature and thickness effectively heat the film evenly and achieve good mixing results. After the film is unrolled, a 300mm x 150mm rectangular block is cut from the middle area of the film. After standing at room temperature for 24 hours, the width is measured and the width change rate is graded as the shrinkage rate.

[0039] The Mooney relaxation time is ML1+4 at 100°C. The time starting from the end of the Mooney test and the stop of the rotor is recorded. The time corresponding to the torque dropping to 80% of the initial value is recorded as the Mooney relaxation time. It can effectively evaluate the stress relaxation characteristics of the rubber compound during processing, reflect the fluidity and processing stability of the rubber molecular chain, and serve as a reference data for extrusion conditions to confirm the degree of crosslinking before vulcanization, so as to clearly adjust process parameters such as fillers and extrusion temperature.

[0040] The crystallization melting peak is determined by freezing the vulcanized rubber in a -10°C environment for 48 hours and then performing a temperature scan test using a differential scanning calorimeter (DSC). The temperature is raised to 80°C at a rate of 10°C / min, and the crystallization melting peak is observed in the temperature rise curve to confirm the chain regularity and branching degree of the colloid, and to confirm that the cooling rate or annealing conditions are adjusted to control the crystallinity.

[0041] In the aging coefficient, the aging conditions are 100°C × 48h. The products of tensile strength and elongation at break before and after aging are calculated respectively. The ratio of the product after aging to the product before aging is recorded as the aging coefficient. The antioxidant, anti-aging agent and filler are adjusted according to the aging coefficient to improve the anti-aging ability of the colloid.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A long-life rubber material with full sea depth adaptability, characterized in that: The invention comprises the following materials: chloroprene rubber, EPDM rubber, carbon black, peroxide DCP, a vinyl-terminated multifunctional monomer and a tackifying resin, wherein the chloroprene rubber is one of conventional sulfur-regulated type, mercaptan-regulated type and mixed-regulated type, the carbon black is one of N550, N660 and N774, the vinyl-terminated multifunctional monomer is one of TAIC and TMPTA, and the tackifying resin is one of C5 resin, C9 resin and coumarone resin.

2. The full-sea-depth adaptable long-life rubber material according to claim 1, characterized in that: The dosage of each component in the rubber material is as follows: chloroprene rubber and EPDM rubber are both 100 phr, carbon black is 40-60 phr, peroxide DCP is 2-5 phr, terminal vinyl multifunctional monomer is 2-4 phr, and tackifying resin is 2-10 phr.

3. The full-sea-depth adaptable long-life rubber material according to claim 2, characterized in that: In the common usage of chloroprene rubber and EPDM rubber in the rubber material, the EPDM rubber is 10-30 phr.

4. A method for manufacturing a full-sea-depth adaptable long-life rubber material according to any one of claims 1 to 3, characterized in that: The manufacturing method comprises the following steps: S1, preparing raw materials of corresponding components according to the rubber material to be manufactured; S2. Set the speed of the internal mixer to 40 rpm and the temperature of the mixing chamber to 70° C. Add chloroprene rubber and EPDM rubber into the internal mixer and mix for 1.5 min. S3. After the chloroprene rubber and EPDM rubber are mixed, carbon black and tackifying resin are added into an internal mixer and mixed again for 3.5 min to obtain a masterbatch; S4. Take out the masterbatch from the internal mixer, adjust the speed of the internal mixer to 20 rpm, the temperature of the mixing chamber to 50°C, put the masterbatch back into the internal mixer, and mix for 1 minute; S5, adding half of the raw material components of peroxide DCP and half of the raw material components of the vinyl-terminated multifunctional monomer into an internal mixer, and mixing for 1.5 minutes; S6. Add the remaining half of the peroxide DCP and the remaining general vinyl-terminated multifunctional monomer into the internal mixer, mix again for 1.5 minutes, and discharge the rubber to obtain the final rubber mix.

Images