A room temperature curing electromagnetic shielding neoprene rubber sealing rubber, its preparation method and application

Abstract

This invention discloses a room-temperature curable electromagnetic shielding chloroprene rubber sealing rubber, its preparation method, and its applications, relating to the field of electromagnetic shielding materials technology. It comprises component A and component B; component A includes a first organic solvent and a chloroprene compound; component B includes triphenylmethane triisocyanate, dibutyltin dilaurate, and a second organic solvent. This invention uses chloroprene rubber as a matrix, and is expected to prepare an electromagnetic shielding sealing rubber material with high viscosity, easy application, and room-temperature deep curing capability.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding materials technology, specifically to a room temperature curing electromagnetic shielding neoprene rubber sealing rubber, its preparation method, and its application. Background Technology

[0002] In today's information age, electromagnetic interference and radiation from electronic devices are ubiquitous. These interferences generate significant amounts of electromagnetic radiation, leading to serious side effects such as electromagnetic interference and electromagnetic incompatibility, posing potential hazards to the normal operation of electronic devices and human health. Electromagnetic shielding rubber materials, as flexible materials, can overcome the shortcomings of traditional electromagnetic shielding materials, such as high processing difficulty, high density, and poor corrosion resistance, representing a new direction in the development of electromagnetic shielding materials.

[0003] Existing electromagnetic shielding rubber types include rubber patches, sealing strips, and sealing rubber. For electromagnetic protection in gaps, sealing rubber is required for plugging. Currently, room-temperature curing silicone rubber is commonly used in industry to prepare electromagnetic shielding sealing rubber. However, because this type of rubber cures through moisture, the curing depth is only 2-4 mm, making it difficult to cure in deep gaps. Under gravity, delamination of the filler and rubber, or self-flowing of the sealing rubber, can easily occur, leading to electromagnetic shielding failure. Therefore, developing a high-performance electromagnetic shielding sealing rubber that can achieve deep curing at room temperature is particularly important. Summary of the Invention

[0004] To address the shortcomings of the aforementioned background technology, this invention provides a room-temperature curable electromagnetic shielding neoprene rubber sealing rubber, its preparation method, and its applications. This invention uses neoprene rubber as the matrix, and is expected to prepare an electromagnetic shielding sealing rubber material with high viscosity, easy application, and room-temperature deep curing capability.

[0005] To achieve the above objectives, the first objective of this invention is to provide a room temperature curing electromagnetic shielding neoprene rubber sealing rubber, comprising component A and component B;

[0006] Component A includes a first organic solvent and chloroprene compound;

[0007] The chloroprene compound comprises the following components by weight: 100 parts of dry chloroprene rubber, 150-400 parts of conductive metal powder, 1-5 parts of conductive reinforcing agent, 3-8 parts of magnesium oxide, 10-20 parts of tackifier, 2-8 parts of anti-settling agent, and 3-8 parts of zinc oxide; the mass ratio of the chloroprene compound to the first organic solvent is 1:(1-2).

[0008] Component B includes triphenylmethane triisocyanate, dibutyltin dilaurate, and a second organic solvent;

[0009] The mass ratio of the triphenylmethane triisocyanate, dibutyltin dilaurate, and the second organic solvent is 1:0.001~0.002:2~4.

[0010] Preferably, the chloroprene rubber dry rubber grade is one or more of A-90, A-100, SN242A, SN242B, SN243, and CR244.

[0011] Preferably, the metal powder is one or more of silver-coated copper, silver-coated aluminum, and silver-coated hollow glass microspheres; the particle size of the metal powder is 10~50μm.

[0012] Preferably, the conductive reinforcing agent is one or more of silver powder, conductive carbon black, graphene, and carbon nanotubes; wherein the silver powder has a particle size of 1~20μm.

[0013] Preferably, the magnesium oxide is highly active magnesium oxide with an iodine uptake value of 80~180 mg / g; the zinc oxide is highly active zinc oxide and / or indirect zinc oxide.

[0014] Preferably, the tackifier is a blend of rosin resin, terpene resin, 2402 phenolic resin, and polyisobutylene in a mass ratio of (1~3):1:1:1;

[0015] The anti-settling agent is fumed silica and / or bentonite.

[0016] Preferably, both the first organic solvent and the second organic solvent are dichloromethane.

[0017] The second objective of this invention is to provide a method for preparing room temperature curing electromagnetic shielding neoprene rubber sealing rubber, comprising the following steps:

[0018] In a two-roll mill, chloroprene rubber is plasticized, magnesium oxide, tackifier, anti-settling agent, conductive metal powder, and conductive reinforcing agent are added, and after being mixed evenly, zinc oxide is added, and after being mixed evenly again, the rubber is discharged and cooled to obtain the compound.

[0019] The compounded rubber is dissolved in an organic solvent to obtain component A;

[0020] Component B is obtained by dissolving triphenylmethane triisocyanate and dibutyltin dilaurate in an organic solvent.

[0021] The third objective of this invention is to provide a method for using room temperature curing electromagnetic shielding neoprene rubber sealing rubber, comprising the following steps:

[0022] Shake component A thoroughly before use, then mix component A and component B thoroughly in a container before application.

[0023] The mass ratio of component A to component B is 80:(1~2).

[0024] The fourth objective of this invention is to provide an application of chloroprene rubber sealing rubber in electromagnetic shielding.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention provides a room-temperature curing electromagnetic shielding chloroprene rubber sealing rubber, its preparation method, and its application. The invention achieves deep room-temperature curing of chloroprene rubber by transforming it into a diene structure under the action of zinc oxide and phenylmethane triisocyanate, which then crosslinks it into a three-dimensional network. Dibutyltin dilaurate is used as a catalyst to shorten the room-temperature curing time. Zinc oxide and magnesium oxide form chelates with 2402 phenolic resin in the tackifier, achieving chemical bridging with the chloroprene rubber. The entanglement of tackifier molecular chains constructs a physical reinforcing network, synergistically increasing the system's adhesive performance. The conductive metal powder has a larger particle size, making it easier to form a conductive network through mutual contact. The conductive reinforcing agent has a smaller particle size, dispersing within the system to fill gaps in the conductive network, achieving high conductivity. The use of an anti-settling agent reduces the rapid settling of fillers, ensuring the stability of the sealing rubber application.

[0027] The electromagnetic shielding sealing rubber prepared by the preparation method provided by this invention can achieve deep curing at room temperature; the prepared electromagnetic shielding sealing rubber has both high shielding performance and high viscosity; the prepared electromagnetic shielding sealing rubber has long-lasting viscosity, ensuring the durability and reliability of electromagnetic shielding protection. Detailed Implementation

[0028] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific embodiments, but the embodiments are not intended to limit the present invention.

[0029] This invention primarily addresses the cross-linking effect of chloroprene rubber, which, due to the presence of chlorine atoms in its molecular chain, can be achieved by metal oxides replacing chlorine atoms. Unlike moisture curing, this allows for deep curing. Furthermore, adhesives made from chloroprene rubber exhibit good bonding properties and can be used to bond various materials, including rubber, plastics, artificial leather, ceramics, concrete, and metals, demonstrating a wide range of applications. Therefore, using chloroprene rubber as a matrix holds promise for developing electromagnetic shielding and sealing rubber materials with high viscosity, ease of application, and room-temperature deep curing capability.

[0030] The first aspect of this invention provides a room temperature curing electromagnetic shielding neoprene rubber sealing rubber, comprising component A and component B;

[0031] Component A includes a first organic solvent and chloroprene compound;

[0032] The chloroprene compound comprises the following components by weight: 100 parts of dry chloroprene rubber, 150-400 parts of conductive metal powder, 1-5 parts of conductive reinforcing agent, 3-8 parts of magnesium oxide, 10-20 parts of tackifier, 2-8 parts of anti-settling agent, and 3-8 parts of zinc oxide; the mass ratio of the chloroprene compound to the first organic solvent is 1:(1-2).

[0033] Component B includes triphenylmethane triisocyanate, dibutyltin dilaurate, and a second organic solvent;

[0034] The mass ratio of the triphenylmethane triisocyanate, dibutyltin dilaurate, and the second organic solvent is 1:0.001~0.002:2~4.

[0035] The chloroprene rubber dry adhesive is one or more of the following grades: A-90, A-100, SN242A, SN242B, SN243, and CR244.

[0036] The metal powder is one or more of silver-coated copper, silver-coated aluminum, and silver-coated hollow glass microspheres; the particle size of the metal powder is 10~50μm.

[0037] The conductive reinforcing agent is one or more of silver powder, conductive carbon black, graphene, and carbon nanotubes; wherein the silver powder has a particle size of 1~20μm.

[0038] The magnesium oxide is highly active magnesium oxide with an iodine uptake value of 80~180 mg / g; the zinc oxide is highly active zinc oxide and / or indirect zinc oxide.

[0039] The tackifier is a blend of rosin resin, terpene resin, 2402 phenolic resin and polyisobutylene, with a mass ratio of (1~3):1:1:1;

[0040] The anti-settling agent is fumed silica and / or bentonite.

[0041] Both the first organic solvent and the second organic solvent are dichloromethane.

[0042] A second aspect of this invention provides a method for preparing room temperature curing electromagnetic shielding neoprene rubber sealing rubber, comprising the following steps:

[0043] In a two-roll mill, chloroprene rubber is plasticized, magnesium oxide, tackifier, anti-settling agent, conductive metal powder, and conductive reinforcing agent are added, and after being mixed evenly, zinc oxide is added, and after being mixed evenly again, the rubber is discharged and cooled to obtain the compound.

[0044] The compounded rubber is dissolved in an organic solvent to obtain component A;

[0045] Component B is obtained by dissolving triphenylmethane triisocyanate and dibutyltin dilaurate in an organic solvent.

[0046] In one embodiment, a method for preparing an electromagnetic shielding sealing rubber includes the following steps:

[0047] In a two-roll mill, chloroprene rubber is plasticized, and magnesium oxide, tackifier, anti-settling agent, conductive metal powder, and conductive reinforcing agent are added. After mixing evenly, zinc oxide is added, and the mixture is mixed evenly again before being discharged and cooled to obtain the compound rubber.

[0048] The above-mentioned rubber compound was dissolved in an organic solvent to obtain component A.

[0049] Triphenylmethane triisocyanate was dissolved in an organic solvent to obtain component B.

[0050] A third aspect of this invention provides a method for using room temperature curing electromagnetic shielding neoprene rubber sealing rubber, comprising the following steps:

[0051] Shake component A thoroughly before use, then mix component A and component B thoroughly in a container before application.

[0052] The mass ratio of component A to component B is 80:(1~2).

[0053] The fourth aspect of this invention provides an application of chloroprene rubber sealing rubber in electromagnetic shielding.

[0054] It should be noted that, unless otherwise specified, the experimental methods used in this invention are all conventional methods; and the reagents and materials used, unless otherwise specified, are all commercially available.

[0055] The following embodiment provides a method for preparing room temperature curing electromagnetic shielding neoprene rubber sealing rubber, as detailed below:

[0056] According to the formula in Table 1, after weighing the materials according to the mass ratio, adjust the roller gap of the open mill, turn on the cooling water of the open mill, set the open mill temperature to 60℃, and the front and rear roller speeds to 21:18 r / min. Perform thin-pass plasticizing of the chloroprene rubber five times. Add magnesium oxide, tackifying resin, anti-settling agent, conductive metal powder, and conductive reinforcing agent, mix for 10 minutes, then add zinc oxide, mix again for 5 minutes, drain the rubber, and cool to obtain the compound. Add dichloromethane and the compound to a single-necked flask in proportion, and stir to dissolve using a polytetrafluoroethylene (PTFE) stirrer for 12 hours. After complete dissolution, remove and package into component A.

[0057] Weigh out phenylmethane triisocyanate, dibutyltin dilaurate and dichloromethane according to the proportion, stir to dissolve, and then take out and dispense into component B.

[0058] Mix components A and B in a specific ratio to prepare an electromagnetic shielding neoprene rubber sealing rubber for application.

[0059] Table 1 Electromagnetic shielding neoprene sealing rubber formulation (by weight)

[0060] project Example 1 Example 2 Example 3 Example 4 Component A Chloroprene rubber dry adhesive A-90 100 0 0 0 Chloroprene rubber dry adhesive SN242A 0 100 0 20 Chloroprene rubber dry adhesive CR244 0 0 100 80 magnesium oxide 5 5 5 5 Silver-plated aluminum powder 300 0 250 150 Silver-plated copper powder 0 300 0 0 Silver powder 10 0 5 0 Conductive carbon black 0 10 0 5 rosin resin 6 5 10 7 Terpene resins 3 5 5 3 Polyisobutylene 3 5 5 3 2402 Phenolic Resin 3 5 5 3 Fumed silica 2 2 2 5 Indirect method for zinc oxide 6 6 5 5 dichloromethane 500 500 400 300 Component B Phenylacetylene triisocyanate 5 5 4 3 Dibutyltin dilaurate 0.005 0.005 0.004 0.003 dichloromethane 15 15 12 9

[0061] The sealing rubbers of Examples 1-4 were subjected to performance tests.

[0062] 1. Test the electromagnetic shielding performance of the adhesive material according to MIL-G-83528.

[0063] 2. Curing depth test: Pour electromagnetic shielding neoprene rubber sealant into several disposable plastic cups, smooth it, and cut open the plastic cups at 12h, 24h, 48h, and 72h to observe the curing depth.

[0064] 3. Adhesion Strength Test: Take a piece of ordinary rubber sheet as the substrate, cut it into strips 25cm wide, and use a grinding wheel or sandpaper to sand the bonding surfaces of the two substrates. Use a cleaning agent to remove surface debris, exposing a fresh interface. Apply the prepared electromagnetic shielding neoprene sealing rubber to the two substrates and let it dry for 20 minutes. Repeat the application and drying process twice more. After this second application, let it dry for 10 minutes before bonding the two substrates together. After the samples have been stored for 4h, 8h, 16h, 24h, and 48h, perform a 180° peel test to measure the peel force at a speed of 100mm / min.

[0065] Table 2 Performance of Examples

[0066] project Example 1 Example 2 Example 3 Example 4 Electromagnetic shielding performance Shielding effectiveness, 10MHz 65 68 45 28 Shielding effectiveness, 10GHz 85 88 58 42 Shielding effectiveness, 18GHz 115 112 75 68 Curing depth 12-hour curing depth, mm 4.2 4.5 5.0 5.5 24-hour curing depth, mm 11.2 10.4 12.5 14.2 48h curing depth, mm 14.8 14.6 16.2 20.5 72h curing depth, mm 16.5 17.2 20.7 24.5 Adhesion strength 4h peel strength, N 12.5 12.5 21.2 25 8h peel strength, N 20.2 26.4 32.5 54.8 16h peel strength, N 49.5 62.2 72.5 78.4 24h peel strength, N 67.5 77.5 105 117.5 48h peel strength, N 72.5 82.4 110 135

[0067] As shown in Table 2, the synergistic effect of zinc oxide, phenylmethane triisocyanate, and dibutyltin dilaurate ensures rapid and deep curing at room temperature. The chelation between zinc oxide, magnesium oxide, and 2402 phenolic resin, as well as the entanglement between the tackifier, achieves high adhesive strength. The synergistic cooperation between conductive metal powder and conductive reinforcing agent constructs a complete conductive network, providing high conductivity and achieving excellent electromagnetic shielding effect. The anti-settling agent ensures the construction stability of the sealing rubber.

[0068] The electromagnetic shielding sealing rubber provided by this invention has good electromagnetic shielding effect, high adhesion strength to the substrate, high adhesion in 4 hours, and basically complete curing after 24 hours. The adhesion is not easily reduced during use, and the curing speed is fast and the depth is large. It is of great significance for electromagnetic shielding protection in deep gaps.

[0069] The above description is only the preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. All those skilled in the art can make various corresponding changes and modifications to the present invention, and all such changes and modifications should fall within the scope of protection of the appended claims without departing from the principles of the invention.

Claims

1. A room temperature vulcanizing electromagnetic shielding neoprene seal rubber, characterized by, The A component and the B component are included; The A component includes a first organic solvent and a chloroprene rubber compound; The chloroprene rubber compound includes the following components by weight: chloroprene rubber dry gum 100 parts, conductive metal powder 150-400 parts, conductive reinforcing agent 1-5 parts, magnesium oxide 3-8 parts, tackifier 10-20 parts, anti-settling agent 2-8 parts, and zinc oxide 3-8 parts; the mass ratio of the chloroprene rubber compound to the first organic solvent is 1: (1-2); The B component includes triphenylmethane triisocyanate, dibutyltin dilaurate, and a second organic solvent; The mass ratio of the triphenylmethane triisocyanate, dibutyltin dilaurate, and the second organic solvent is 1: 0.001-0.002: 2-4; The chloroprene rubber dry gum is one or more of A-90, A-100, SN242A, SN242B, SN243, and CR244; The metal powder is one or more of silver-coated copper, silver-coated aluminum, and silver-coated hollow glass microbeads; the particle size of the metal powder is 10-50 μm; The conductive reinforcing agent is one or more of silver powder, conductive carbon black, graphene, and carbon nanotubes; the particle size of the silver powder is 1-20 μm; The magnesium oxide is high-activity magnesium oxide with an iodine absorption value of 80-180 mg / g; the zinc oxide is high-activity zinc oxide and / or indirect zinc oxide; The tackifier is a blend of rosin resin, terpene resin, 2402 phenolic resin, and polyisobutylene with a mass ratio of (1-3): 1: 1: 1; The anti-settling agent is fumed white carbon black and / or bentonite; The first organic solvent and the second organic solvent are both dichloromethane.

2. A process for the preparation of a room temperature vulcanizable electromagnetic shielding neoprene seal rubber as claimed in claim 1, characterized in that, The method includes the following steps: In an open mill, the chloroprene rubber is plasticized, and magnesium oxide, a tackifier, an anti-settling agent, conductive metal powder, and conductive reinforcing agent are added; after uniform mixing, zinc oxide is added, and the mixture is again uniformly mixed and discharged; the mixture is cooled to obtain a rubber compound; The rubber compound is dissolved in an organic solvent to obtain the A component; Triphenylmethane triisocyanate and dibutyltin dilaurate are dissolved in an organic solvent to obtain the B component.

3. A method of using the room temperature vulcanizing electromagnetic shielding neoprene seal rubber as claimed in claim 1, characterized in that, The method includes the following steps: Before use, the A component is thoroughly shaken, and then the A component and the B component are thoroughly mixed and stirred in a container before construction; The mass ratio of the A component to the B component is 80: (1-2).

4. A chloroprene rubber seal rubber as claimed in claim 1 for use in electromagnetic shielding.