Rubber with electromagnetic shielding and wave absorbing functions and preparation method thereof

Abstract

The invention relates to the technical field of rubber products, in particular to rubber with electromagnetic shielding and wave absorbing functions and a preparation method thereof.The rubber with the electromagnetic shielding and wave absorbing functions is prepared from, by mass, 5-50 parts of rubber; the mass part of the filling agent is 50 to 93 parts; and 1-2 parts by mass of a compounding agent. The invention relates to a preparation method of rubber with electromagnetic shielding and wave absorbing functions. The preparation method comprises the following steps: plasticizing raw rubber on an open mill; filling agents are added into the plasticized raw rubber in batches; the rubber material is subjected to primary sheet processing on an open mill, the sheet processing comprises three times of cyclic operation, and the time of each cyclic operation is not less than 30 minutes; standing the obtained rubber material, wherein the standing time is 8 to 24 hours; and carrying out secondary sheet processing on the obtained rubber material to finally obtain the finished product rubber. The rubber product provided by the invention overcomes the technical problem that a single filler is difficult to realize good electromagnetic shielding and wave-absorbing properties at the same time.

Description

Technical Field

[0001] This application relates to the technical field of rubber products, and particularly relates to a rubber with electromagnetic shielding and wave absorption functions and a preparation method thereof. Background Art

[0002] With the rapid development of industry, the demand for rubber is not only for simple sealing and shock absorption functions. Currently, the demand for materials with electromagnetic shielding and wave absorption functions is increasing in industrial, military, and civilian fields. Although traditional metal shielding materials have good electromagnetic shielding effects, they have disadvantages such as high weight, difficult processing, and easy corrosion. Currently, common conductive rubbers on the market are mainly prepared by compounding conductive fillers (such as carbon black, graphite, metal powders, etc.) with a rubber matrix. However, it is difficult for a single filler to achieve both good electromagnetic shielding and wave absorption performances simultaneously. Summary of the Invention

[0003] This application aims to solve at least one of the above technical problems in the prior art to some extent. Therefore, an embodiment of this application provides a rubber with electromagnetic shielding and wave absorption functions and a preparation method thereof. The rubber product of this application not only solves the problems of high weight, difficult processing, and easy corrosion of traditional metal shielding materials but also overcomes the technical problem that it is difficult for a single filler to achieve both good electromagnetic shielding and wave absorption performances simultaneously, providing a new solution for the application of electromagnetic shielding materials.

[0004] A rubber with electromagnetic shielding and wave absorption functions comprises the following raw materials:

[0005] Rubber, with a mass fraction of 5 - 50 parts;

[0006] Filler, with a mass fraction of 50 - 93 parts;

[0007] Compound agent, with a mass fraction of 1 - 2 parts.

[0008] In an optional or preferred embodiment, the rubber includes: silicone rubber, ethylene propylene rubber, nitrile rubber; the filler includes: conductive or magnetic metal powders; the compound agent includes: one or more of vulcanizing agent, coupling agent, reinforcing agent, structure control agent, and process improver.

[0009] In an optional or preferred embodiment, the filler is one or more of carbonyl iron powder, ferrite, and silver powder.

[0010] A preparation method of a rubber with electromagnetic shielding and wave absorption functions for preparing the above rubber comprises the following steps:

[0011] (1) Plasticize the raw rubber on an open mill;

[0012] (2) Add the filler to the plasticized raw rubber in batches until the filler is completely mixed in;

[0013] (3) Conduct the first thin sheet processing on the rubber compound obtained in step (2) on an open mill. The first thin sheet processing is carried out for 3 cycle operations, and the time for each cycle operation is not less than 30 minutes;

[0014] (4) Let the rubber compound obtained in step (3) stand still, and the standing time is 8 - 24 hours;

[0015] (5) Conduct the second thin sheet processing on the rubber compound obtained in step (4) in the operation mode of step (3) to finally obtain the finished rubber.

[0016] In an optional or preferred embodiment, the steps for adding the filler include:

[0017] S1. Divide the filler into 3 or more portions;

[0018] S2. Slowly add the filler at a gradually slowing down speed;

[0019] S3. When it is difficult to incorporate the filler, pause for a period of time and then continue to add the filler;

[0020] Repeat step S2 and step S3 until all the filler is added and the incorporation of the filler is completed.

[0021] In an optional or preferred embodiment, in step S2, the adding speed of the filler is 1 g / min - 3 g / min.

[0022] In an optional or preferred embodiment, in step S3, the time for pausing the addition of the filler is 8 - 24 h.

[0023] In an optional or preferred embodiment, in the first thin sheet processing, the roll gap between the two rollers is 0.5 - 1.0 mm.

[0024] In an optional or preferred embodiment, in the 3 cycle operations of the thin sheet processing, the time interval between two adjacent operations is not less than 30 min.

[0025] Based on the above technical solutions, the embodiments of the present application have at least the following beneficial effects: The rubber products of the present application not only solve the problems of the traditional metal shielding material such as large weight, difficult processing, and easy corrosion, but also overcome the technical problem that it is difficult for a single filler to simultaneously achieve good electromagnetic shielding and wave absorption performance. Detailed implementation manners

[0026] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts shall fall within the scope of protection of this application.

[0027] The following further describes the implementation manners of this application in conjunction with embodiments. The following embodiments are used to illustrate this application, but cannot be used to limit the scope of this application.

[0028] In the description of the embodiments of this application, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is only for the convenience of describing the embodiments of this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the embodiments of this application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0029] In the description of the embodiments of this application, it should be noted that unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific situations.

[0030] In the embodiments of this application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0031] With the rapid development of industry, the demand for rubber is not only for simple sealing and shock absorption functions. At present, the demand for materials with electromagnetic shielding and wave absorption functions is increasing in industrial, military, and civilian fields. Although traditional metal shielding materials have good electromagnetic shielding effects, they have disadvantages such as high weight, difficult processing, and easy corrosion. Currently, the common conductive rubbers on the market are mainly prepared by compounding conductive fillers (such as carbon black, graphite, metal powders, etc.) with rubber matrices. However, it is difficult for a single filler to achieve good electromagnetic shielding and wave absorption performance simultaneously.

[0032] The present invention provides a rubber with electromagnetic shielding and wave absorption functions, comprising the following raw materials:

[0033] Rubber, in an amount of 5 - 50 parts by mass;

[0034] Filler, in an amount of 50 - 93 parts by mass;

[0035] Compound agent, in an amount of 1 - 2 parts by mass.

[0036] Among them, the rubber includes: silicone rubber, ethylene - propylene rubber, nitrile rubber; the filler includes: conductive or magnetic metal powders; the compound agent includes: one or more of vulcanizing agents, coupling agents, reinforcing agents, structure - controlling agents, and process - improving agents.

[0037] In some embodiments, the filler is one or more of carbonyl iron powder, ferrite, and silver powder.

[0038] The following further illustrates the present invention with specific embodiments.

[0039] Example 1

[0040] In this example, the following raw materials are used to prepare a rubber with electromagnetic shielding and wave absorption functions: silicone rubber: 30 parts, carbonyl iron powder: 65 parts, vulcanizing agent: 1.5 parts, coupling agent: 0.5 part.

[0041] The specific preparation steps are as follows:

[0042] Step 1: Place the silicone rubber on an open mill and perform plasticization treatment at room temperature for 30 minutes;

[0043] Step 2: Divide 65 parts of carbonyl iron powder into 4 parts (each part is about 16.25 parts) and add them in the following manner: The first part: add at a speed of 2 g / min, the second part: add at a speed of 1.5 g / min, the third and fourth parts: add at a speed of 1 g / min. When there is difficulty in incorporating the powder, pause for 12 hours and then continue to add;

[0044] Step 3: Conduct the first thin sheet processing of the mixed rubber compound on a two-roll mill: Set the roll gap to 0.8 mm, conduct 3 cycles of operation, each cycle for 35 minutes, with an interval of 40 minutes between adjacent operations;

[0045] Step 4: Take out the rubber compound and let it stand for 16 hours;

[0046] Step 5: After standing, conduct the second thin sheet processing in the same operation manner as in Step 3 to finally obtain the finished rubber.

[0047] The prepared rubber has the following performance characteristics: Electromagnetic shielding effectiveness: It can reach 45 - 60 dB in the frequency band of 1 - 18 GHz, reflection loss: The maximum can reach -25 dB in the frequency band of 8 - 18 GHz, tensile strength: 12 MPa, elongation at break: 280%.

[0048] Example 2

[0049] In this example, the following raw materials are used to prepare the rubber with electromagnetic shielding and wave absorption functions: Ethylene propylene rubber: 20 parts, ferrite powder: 70 parts, silver powder: 5 parts, vulcanizing agent: 1.2 parts, reinforcing agent: 0.8 parts.

[0050] The specific preparation steps are as follows:

[0051] Step 1: Plasticize the ethylene propylene rubber on a two-roll mill for 40 minutes;

[0052] Step 2: Add 75 parts of filler (a mixture of ferrite powder and silver powder) in 3 portions: The first portion: Add at a speed of 2.5 g / min; The second portion: Add at a speed of 1.8 g / min; The third portion: Add at a speed of 1.2 g / min; When there is difficulty in incorporating the powder, pause for 16 hours and then continue;

[0053] Step 3: The first thin sheet processing: Set the roll gap to 0.6 mm, conduct 3 cycles of operation, each cycle for 40 minutes; The interval between adjacent operations is 35 minutes;

[0054] Step 4: Let it stand for 20 hours;

[0055] Step 5: After standing, conduct the second thin sheet processing in the same operation manner as in Step 3 to obtain the finished rubber.

[0056] The prepared rubber has the following performance characteristics: Electromagnetic shielding effectiveness: It can reach 50 - 65 dB in the frequency band of 1 - 18 GHz; Reflection loss: The maximum can reach -28 dB in the frequency band of 8 - 18 GHz; Tensile strength: 14 MPa; Elongation at break: 260%;

[0057] Example 3

[0058] In this embodiment, the following raw materials are used to prepare rubber with electromagnetic shielding and wave absorption functions: nitrile rubber: 15 parts; carbonyl iron powder: 45 parts; ferrite: 30 parts; vulcanizing agent: 1.6 parts; structure control agent: 0.4 parts.

[0059] The specific production steps are as follows:

[0060] Step 1: Plasticize nitrile rubber for 35 minutes;

[0061] Step 2: Gradually add 75 parts of filler in 4 portions: The first and second portions are added at a speed of 2 g / min; the third and fourth portions are added at a speed of 1.5 g / min; pause for 20 hours when it is difficult to incorporate the filler;

[0062] Step 3: First thin sheet processing: The roll gap is 0.7 mm; 3 cycles, each cycle for 45 minutes; the interval between adjacent two operations is 40 minutes;

[0063] Step 4: Let it stand for 24 hours;

[0064] Step 5: After standing, perform the second thin sheet processing in the same operation mode as in Step 3 to obtain the finished rubber.

[0065] In this application, by adding fillers in batches, the agglomeration phenomenon is avoided. The reasonable standing time ensures the release of internal stress. Multiple thin sheet processes improve the dispersion uniformity, and the strictly controlled process parameters ensure the stability of product quality.

[0066] This application can select different rubber matrices and filler ratios according to different application scenarios, and has good adaptability.

[0067] The rubber product of this application not only solves the problems of heavy weight, difficult processing, and easy corrosion of traditional metal shielding materials, but also overcomes the technical problem that it is difficult for a single filler to achieve good electromagnetic shielding and wave absorption performance at the same time, providing a new solution for the application of electromagnetic shielding materials.

[0068] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of this application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0069] The above embodiments of the present application have been described in detail, but the present application is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the spirit of the present application.

Claims

1. A rubber having electromagnetic shielding and wave absorbing functions, characterized in that: Including the following ingredients: Rubber, 5-50 parts by weight; Filler, 50-93 parts by weight; Compounding agent, mass fraction is 1-2 parts.

2. The electromagnetic shielding and wave absorbing rubber according to claim 1, characterized in that: The rubber includes silicone rubber, ethylene propylene rubber, and nitrile rubber; the filler includes conductive or magnetic metal powder; and the compounding agent includes one or more of a vulcanizing agent, a coupling agent, a reinforcing agent, a structure control agent, and a process improving agent.

3. The electromagnetic shielding and wave absorbing rubber according to claim 2, characterized in that: The filler is one or more of carbonyl iron powder, ferrite, and silver powder.

4. A method for preparing a rubber having electromagnetic shielding and wave absorbing functions, used for preparing the rubber according to claim 1, characterized in that: The following steps are involved: (1) placing the raw rubber on an open mixing mill for plasticization; (2) adding fillers to the plasticized raw rubber in batches until the fillers are completely mixed; (3) subjecting the rubber material obtained in step (2) to a first slicing process on an open mixing mill, wherein the first slicing process is repeated three times, and each cycle lasts no less than 30 minutes; (4) allowing the rubber obtained in step (3) to stand for 8 to 24 hours; (5) The rubber material obtained in step (4) is subjected to a second thin-sheet processing according to the operation method of step (3) to finally obtain a finished rubber product.

5. The method for preparing the rubber having electromagnetic shielding and wave absorbing functions according to claim 4, characterized in that: The step of adding the filler comprises: S1, dividing the filler into 3 or more portions; S2. Slowly add the filler at a gradually decreasing speed; S3. When it is difficult to eat the powder, stop for a while and then continue to add the filler; Repeat step S2 and step S3 until all the fillers are added, so that the powder eating is completed.

6. The method for preparing the rubber having electromagnetic shielding and wave absorbing functions according to claim 5, characterized in that: In the step S2, the filler is added at a rate of 1 g / min to 3 g / min.

7. The method for preparing the rubber having electromagnetic shielding and wave absorbing functions according to claim 5, characterized in that: In step S3, the time for suspending the feeding is 8 to 24 hours.

8. The method for preparing the rubber having electromagnetic shielding and wave absorbing functions according to claim 5, characterized in that: In the first thin sheet processing, the roller distance between the two rollers is 0.5-1.0 mm.

9. The method for preparing the rubber having electromagnetic shielding and wave absorbing functions according to claim 5, characterized in that: In the three cycles of thin film processing, the time interval between two adjacent operations shall not be less than 30 minutes.