High-resilience electromagnetic shielding adhesive and preparation method thereof

Abstract

The invention discloses a high-rebound electromagnetic shielding adhesive and a preparation method thereof. The high-rebound electromagnetic shielding adhesive is prepared from raw materials including the following components: 70-100 parts by weight of base adhesive, 1-10 parts by weight of side hydrogenated silicone oil, 1-5 parts by weight of end side hydrogenated silicone oil, 1-5 parts by weight of tackifier, 0.01-0.03 parts by weight of inhibitor, 0.1-0.5 parts by weight of platinum catalyst, 10-30 parts by weight of diluent, 150-200 parts by weight of conductive filler; the base adhesive is prepared from raw materials including the following components: 60-90 parts by weight of branched vinyl silicone oil, 20-35 parts by weight of fumed silica, 1-7 parts by weight of tetramethyl divinyl silazane, and 1-5 parts by weight of water. The electromagnetic shielding adhesive has excellent mechanical properties, good resilience, is not prone to permanent deformation, and the shielding effect remains good during long-term use.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic shielding adhesives, and in particular to a high-resilience electromagnetic shielding adhesive and a preparation method thereof. Background Art

[0002] With the development of communication fields such as 5G base stations, many electronic devices will be subject to external electromagnetic interference. The electromagnetic shielding problem has always been a major problem affecting the long-term stable use of electronic instruments and equipment. In order to protect the stable operation of electronic equipment, it is necessary to shield external electromagnetic signals, so electromagnetic shielding glue came into being. At present, there are many introductions and studies on electromagnetic shielding glue. For example, CN111718672A introduces a high-performance silicone conductive shielding glue and its preparation method. However, during long-term use, it will be squeezed by the equipment, and the colloid will undergo a relatively large permanent deformation. Due to the irreversible deformation, its internal structure will be damaged to a certain extent, thereby affecting the electromagnetic shielding effect. Therefore, electromagnetic shielding glue has great requirements for the resilience and deformation resistance of the colloid during use. Most of the current electromagnetic shielding glues have poor resilience and deformation resistance. The deformation after the seal is loaded is not easy to recover, and permanent deformation occurs. Especially after use in harsh environments, a certain degree of damage will occur, resulting in sealing failure, and then affecting the shielding effectiveness.

[0003] There is still very little research on the resilience and compression performance of electromagnetic shielding glue, which is crucial to the electromagnetic shielding performance and the use of electronic equipment. How to effectively improve the resilience of electromagnetic shielding glue to effectively protect the use of electronic equipment is a technical problem. Summary of the invention

[0004] The purpose of the present invention is to provide a high-rebound electromagnetic shielding adhesive, which has excellent mechanical properties, good resilience, is not prone to permanent deformation, and is conducive to maintaining a good shielding effect for electronic equipment during long-term use.

[0005] In order to achieve the above object, the present invention includes the following technical solutions.

[0006] A high-resilience electromagnetic shielding adhesive is prepared from raw materials including the following components:

[0007] 70-100 parts by weight of base glue,

[0008] 1-10 parts by weight of side hydrogenated silicone oil,

[0009] 1-5 parts by weight of end-side hydrogenated silicone oil,

[0010] 1-5 parts by weight of a tackifier,

[0011] 0.01-0.03 parts by weight of an inhibitor,

[0012] 0.1-0.5 parts by weight of a platinum catalyst,

[0013] 10-30 parts by weight of diluent,

[0014] 150-200 parts by weight of conductive filler;

[0015] The gum base is prepared from raw materials including the following components:

[0016] 60-90 parts by weight of branched vinyl silicone oil,

[0017] 20-35 parts by weight of fumed silica,

[0018] 1-7 parts by weight of tetramethyldivinylsilazane,

[0019] 1-5 parts by weight of water;

[0020] The structure of the branched vinyl silicone oil is:

[0021]

[0022] In some embodiments, the high resilience electromagnetic shielding adhesive is prepared from raw materials including the following components:

[0023] 78-85 parts by weight of base glue,

[0024] 2-3 parts by weight of side hydrogenated silicone oil,

[0025] 2-3 parts by weight of end-side hydrogenated silicone oil,

[0026] 1-2 parts by weight of a tackifier,

[0027] 0.01-0.03 parts by weight of an inhibitor,

[0028] 0.1-0.5 parts by weight of platinum catalyst,

[0029] 15-25 parts by weight of diluent,

[0030] 150-200 parts by weight of conductive filler.

[0031] In some embodiments, the gum base is prepared from raw materials including the following components:

[0032] 68-75 parts by weight of branched vinyl silicone oil,

[0033] 25-30 parts by weight of fumed silica,

[0034] 4-5 parts by weight of tetramethyldivinylsilazane,

[0035] 1-3 parts by weight of water.

[0036] In some embodiments, the branched vinyl silicone oil is prepared by a hydrosilylation reaction of a vinyl-terminated silicone oil and a side hydrogen-containing silicone oil under the action of a platinum catalyst, and the reaction formula is as follows:

[0037]

[0038] In some embodiments, the vinyl content of the vinyl-terminated silicone oil is 0.2wt%-0.6wt%; the viscosity of the hydrogen-containing silicone oil is 80mPa·s-500mPa·s, and the hydrogen content is 0.05wt%-0.36wt%.

[0039] In some embodiments, the vinyl content of the vinyl-terminated silicone oil is 0.4wt%-0.5wt%; the viscosity of the hydrogen-containing silicone oil is 100mPa·s-200mPa·s, and the hydrogen content is 0.08wt%-0.12wt%.

[0040] In some embodiments, the viscosity of the branched vinyl silicone oil is 8000mPa·s to 30000mPa·s, and the vinyl content thereof is 0.1wt% to 0.4wt%.

[0041] In some embodiments, the viscosity of the branched vinyl silicone oil is 9000mPa·s to 15000mPa·s, and the vinyl content thereof is 0.1wt% to 0.2wt%.

[0042] In some embodiments, the viscosity of the branched vinyl silicone oil is 9000mPa·s-10000mPa·s, and the vinyl content thereof is 0.12wt%-0.18wt%.

[0043] In some embodiments, the mass ratio of the vinyl-terminated silicone oil to the hydrogen-containing silicone oil is 10-15:1.

[0044] In some embodiments, the mass ratio of the terminal vinyl silicone oil to the side hydrogen silicone oil is 12-14:1.

[0045] In some embodiments, the preparation method of the branched vinyl silicone oil comprises the following steps:

[0046] Add hydrogenated silicone oil, platinum catalyst and solvent into the reaction bottle, stir evenly, then drop vinyl-terminated silicone oil into the bottle. After the dropwise addition, heat to 80-95°C and react for 1-3 hours to obtain the product.

[0047] In some embodiments, the solvent is toluene.

[0048] In some embodiments, the specific surface area of ​​the fumed silica is 100 m2 / g-350m 2 / g.

[0049] In some embodiments, the specific surface area of ​​the fumed silica is 200 m 2 / g-300m 2 / g.

[0050] In some embodiments, the method for preparing the gum base comprises the following steps:

[0051] The branched vinyl silicone oil, tetramethyldivinylsilazane and water are mixed, and the fumed silica is added in batches. The temperature is raised to 110° C.-130° C., vacuum stirred for 2 h-5 h, and cooled to obtain the base rubber.

[0052] In some embodiments, the vacuum degree of the vacuum stirring is -85KPa to -100KPa.

[0053] In some embodiments, the viscosity of the side hydrogenated silicone oil is 10 mPa·s-200 mPa·s, and the hydrogen content thereof is 0.18 wt%-0.75 wt%.

[0054] In some embodiments, the viscosity of the side hydrogenated silicone oil is 15 mPa·s-25 mPa·s, and the hydrogen content thereof is 0.3 wt%-0.4 wt%.

[0055] In some embodiments, the viscosity of the end-side hydrogenated silicone oil is 30 mPa·s-100 mPa·s, and the hydrogen content thereof is 0.1 wt%-1 wt%.

[0056] In some embodiments, the viscosity of the end-side hydrogenated silicone oil is 30 mPa·s-40 mPa·s, and the hydrogen content thereof is 0.2 wt%-0.35 wt%.

[0057] In some embodiments, the adhesion promoter is selected from at least one of γ-methacryloxypropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, and 3-isocyanatopropyltriethoxysilane.

[0058] In some embodiments, the inhibitor is selected from at least one of 1-ethyn-1-cyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol and 3,6-dimethyl-1-heptyn-3-ol.

[0059] In some embodiments, the catalyst is selected from at least one of a Custer catalyst, chloroplatinic acid, a chloroplatinic acid-isopropanol complex, and a chloroplatinic acid-divinyltetramethyldisiloxane complex.

[0060] In some embodiments, the diluent is selected from at least one of isopropyl alcohol, ethanol, acetone, butanone, kerosene, octamethylcyclotetrasiloxane, octamethyltrisiloxane, dimethyl carbonate and decamethyltetrasiloxane.

[0061] In some embodiments, the conductive filler is nickel-coated graphite powder with a particle size of 20um-150um.

[0062] In some of the embodiments, the nickel-coated graphite powder has an appearance of one or more of spherical, quasi-spherical and flaky.

[0063] The present invention also provides a method for preparing the above-mentioned high-resilience electromagnetic shielding adhesive, including the following technical solutions.

[0064] A method for preparing a high-resilience electromagnetic shielding adhesive comprises the following steps:

[0065] The base glue, conductive filler, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, tackifier, catalyst, inhibitor and diluent are sequentially added into a disperser and stirred in vacuum for 10 min-30 min to obtain the high resilience electromagnetic shielding glue.

[0066] The present invention has the following beneficial effects:

[0067] In view of the problem that current electromagnetic shielding adhesives are prone to permanent deformation during use and have poor rebound ability, which leads to reduced electromagnetic shielding effectiveness and affects the use of electronic equipment, the present invention provides a high-rebound electromagnetic shielding adhesive and a preparation method thereof. The electromagnetic shielding adhesive has excellent mechanical properties, is not prone to permanent deformation, has good rebound resilience, and is conducive to electronic equipment maintaining a good electromagnetic shielding effect during long-term use.

[0068] In the prior art, the base adhesive of the addition-type electromagnetic shielding adhesive is generally made of ordinary terminal vinyl silicone oil with double bonds at both ends, and the hydrogen-containing silicone oil used is also ordinary side hydrogen-containing silicone oil. The formation of a cross-linked network structure can only rely on multiple Si-H groups on the side chain of the side hydrogen-containing silicone oil. The cross-linked network structure and density formed are limited, and the density of the cross-linked network has a very large influence on resilience and deformation resistance. The denser the cross-linked network, the stronger its resilience and deformation resistance.

[0069] The invention starts from the structural design of the cross-linked network. Firstly, a novel branched vinyl silicone oil is prepared by a silylation reaction of a vinyl-terminated silicone oil and a side hydrogen-containing silicone oil under the action of a platinum catalyst. Then, the branched vinyl silicone oil is used to replace the traditional vinyl-terminated silicone oil as the vinyl component, thereby improving the reaction activity of the vinyl component. Meanwhile, the branched vinyl silicone oil molecular chain has particularly many side chains. The cross-linked network generated after the cross-linking reaction is dense and has better resilience. Secondly, the surface of fumed silica is treated with tetramethyl divinyl silazane containing vinyl groups, so that the vinyl groups in the tetramethyl divinyl silazane can be removed. The alkenyl group is grafted onto the surface of white carbon black to provide more reactive groups. In the later reaction, more reactive active points and crosslinking points can be provided to react with hydrogen-containing silicone oil, thereby increasing the crosslinking density of the colloid, thereby increasing the resilience and deformation resistance of the colloid; again, an appropriate amount of end-side hydrogen-containing silicone oil is added to increase the crosslinking points and crosslinking network density in an all-round way. The increase in crosslinking points and crosslinking density can improve the system's deformation resistance when encountering external forces, and can effectively improve the resilience performance, thereby maintaining the electromagnetic shielding effectiveness in actual use. It is squeezed by external forces without attenuation, thereby enhancing the long-term normal use of electronic equipment. Under the coordinated cooperation of the various components of the present invention, the electromagnetic shielding adhesive of the present invention is not easy to permanently deform while maintaining excellent mechanical properties, and has good resilience, which is conducive to electronic equipment maintaining a good electromagnetic shielding effect during long-term use. DETAILED DESCRIPTION

[0070] The technical scheme of the present invention is further illustrated by specific examples below. Those skilled in the art should understand that the examples are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0071] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0072] The terms "including" and "having" and any variations thereof of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, device, product or equipment comprising a series of steps is not limited to the listed steps or modules, but may optionally include steps not listed, or may optionally include other steps inherent to these processes, methods, products or equipment.

[0073] In the present invention, the term "multiple" refers to two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0074] The viscosity described in the present invention refers to the viscosity under the test condition of 25°C.

[0075] The "side hydrogen-containing silicone oil" of the present invention refers to a polydimethylmethylhydrogensiloxane having a Si-H group in the side chain terminated with a methyl group, and its structural formula is as follows:

[0076]

[0077] The "terminal hydrogen-containing silicone oil" of the present invention refers to H-terminated polydimethylsiloxane, and its structural formula is as follows:

[0078]

[0079] The "terminal hydrogen-containing silicone oil" of the present invention refers to a polydimethylsiloxane terminated with H and also containing a Si-H group on the side chain, and its structural formula is as follows:

[0080]

[0081] The "vinyl-terminated silicone oil" of the present invention refers to polydimethylsiloxane terminated with vinyl, and its structural formula is as follows:

[0082] Vi means vinyl.

[0083] The "side vinyl silicone oil" of the present invention refers to a polydimethylmethylvinylsiloxane having a Si-Vi group in the side chain terminated with a methyl group, and its structural formula is as follows:

[0084] Vi means vinyl.

[0085] The reaction formula for preparing branched vinyl silicone oil according to the present invention is as follows:

[0086]

[0087] Among them, Vi refers to vinyl

[0088] The preparation method comprises the following steps: a. a three-necked flask is equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer, 100 parts by weight of a side hydrogen-containing silicone oil with a viscosity of 100 mPa·s and a hydrogen content of 0.1 wt%, 5 ppm (based on Pt content) of a Custer catalyst and 500 parts of toluene are added, and stirred evenly;

[0089] b: Slowly drip 1300 parts of vinyl-terminated silicone oil with a vinyl content of 0.43 wt% into the above mixed solution within 1 hour, then heat to 90°C and reflux for 2 hours;

[0090] c: After the reaction is completed, the solvent is removed by rotary evaporation and the catalyst is removed by activated carbon adsorption to obtain branched vinyl silicone oil; the viscosity is measured to be about 9800 mPa·s and the vinyl content is 0.15wt%.

[0091] Example 1

[0092] The raw material composition of the base rubber is as follows:

[0093] 70 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15 wt%,

[0094] 30 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0095] 5 parts by weight of tetramethyldivinylsilazane,

[0096] 3 parts by weight of deionized water.

[0097] The preparation method of the base glue comprises the following steps:

[0098] a) Add the branched vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 20 minutes;

[0099] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 3h;

[0100] c). Cool to room temperature to obtain the base glue.

[0101] The raw materials of electromagnetic shielding glue are as follows:

[0102] 80 parts by weight of base glue,

[0103] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0104] 2 parts by weight of end-side hydrogenated silicone oil, with a hydrogen content of 0.28 wt% and a viscosity of 35 mPa·s,

[0105] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0106] 0.01 parts by weight of the inhibitor 3-methyl-1-butyn-3-ol,

[0107] 0.5 parts by weight of Custer platinum catalyst,

[0108] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0109] 150 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0110] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0111] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor, diluent, etc. are sequentially added into a disperser under vacuum (-95KPa) and stirred for 10 minutes (speed 1000 rpm) to obtain the electromagnetic shielding glue.

[0112] Example 2

[0113] The raw material composition of the base rubber is as follows:

[0114] 70 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15 wt%,

[0115] 30 parts by weight of fumed silica, with a specific surface area of ​​300 m 2 / g,

[0116] 5 parts by weight of tetramethyldivinylsilazane,

[0117] 3 parts by weight of deionized water.

[0118] The preparation method of the base glue comprises the following steps:

[0119] a) Add the branched vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 20 minutes;

[0120] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 3h;

[0121] c). Cool to room temperature to obtain the base glue.

[0122] The raw materials of electromagnetic shielding glue are as follows:

[0123] 80 parts by weight of base glue,

[0124] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36 wt% and a viscosity of 20 mPa·s

[0125] 2 parts by weight of end-side hydrogenated silicone oil, with a hydrogen content of 0.28 wt% and a viscosity of 35 mPa·s

[0126] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0127] 0.01 parts by weight of the inhibitor 3,5-dimethyl-1-hexyn-3-ol,

[0128] 0.5 parts by weight of platinum catalyst chloroplatinic acid-divinyltetramethyldisiloxane complex,

[0129] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0130] 170 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0131] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0132] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor and diluent are sequentially added into a disperser under vacuum (-95KPa) and stirred for 10 minutes (speed 1000 rpm) to obtain the electromagnetic shielding glue.

[0133] Example 3

[0134] The raw material composition of the base rubber is as follows:

[0135] 70 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15 wt%,

[0136] 30 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0137] 5 parts by weight of tetramethyldivinylsilazane,

[0138] 3 parts by weight of deionized water.

[0139] The preparation method of the base glue comprises the following steps:

[0140] a) Add the branched vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 20 minutes;

[0141] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 130°C and stir in vacuum (-95KPa) for 3h;

[0142] c). Cool to room temperature to obtain the base glue.

[0143] The raw materials of electromagnetic shielding glue are as follows:

[0144] 80 parts by weight of base glue,

[0145] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0146] 2 parts by weight of end-side hydrogenated silicone oil, with a hydrogen content of 0.28 wt% and a viscosity of 35 mPa·s

[0147] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0148] 0.01 parts by weight of the inhibitor 3,5-dimethyl-1-hexyn-3-ol,

[0149] 0.5 parts by weight of platinum catalyst chloroplatinic acid,

[0150] 20 parts by weight of diluent dimethyl carbonate,

[0151] 200 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0152] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0153] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor and diluent are sequentially added into a disperser under vacuum (-95KPa) and stirred for 15 minutes (speed 1000 rpm) to obtain the electromagnetic shielding glue.

[0154] Example 4

[0155] The raw material composition of the base rubber is as follows:

[0156] 75 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15wt%,

[0157] 25 parts by weight of fumed silica, with a specific surface area of ​​300 m 2 / g,

[0158] 5 parts by weight of tetramethyldivinylsilazane,

[0159] 3 parts by weight of deionized water.

[0160] The preparation method of the base glue comprises the following steps:

[0161] a) Add the branched vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 30 minutes;

[0162] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 130°C and stir in vacuum (-95KPa) for 3h;

[0163] c). Cool to room temperature to obtain the base glue.

[0164] The raw materials of electromagnetic shielding glue are as follows:

[0165] 80 parts by weight of base glue,

[0166] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0167] 2 parts by weight of end-side hydrogenated silicone oil, with a hydrogen content of 0.28 wt% and a viscosity of 35 mPa·s,

[0168] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0169] 0.01 parts by weight of the inhibitor 3,5-dimethyl-1-hexyn-3-ol,

[0170] 0.5 parts by weight of platinum catalyst chloroplatinic acid-divinyltetramethyldisiloxane complex,

[0171] 20 parts by weight of diluent dimethyl carbonate,

[0172] 150 parts by weight of spherical nickel-coated graphite powder with a particle size of 80 μm.

[0173] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0174] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor, diluent, etc. are sequentially added into a disperser under vacuum (-95KPa) and stirred for 10 minutes (speed 1000 rpm) to obtain the electromagnetic shielding glue.

[0175] Example 5

[0176] The raw material composition of the base rubber is as follows:

[0177] 75 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15wt%,

[0178] 25 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0179] 5 parts by weight of tetramethyldivinylsilazane,

[0180] 3 parts by weight of deionized water.

[0181] The preparation method of the base glue comprises the following steps:

[0182] a) Add the branched vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 30 minutes;

[0183] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 4h;

[0184] c). Cool to room temperature to obtain the base glue.

[0185] The raw materials of electromagnetic shielding glue are as follows:

[0186] 80 parts by weight of base glue,

[0187] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0188] 2 parts by weight of end-side hydrogenated silicone oil, with a hydrogen content of 0.28 wt% and a viscosity of 35 mPa·s,

[0189] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0190] 0.01 parts by weight of the inhibitor 1-ethynyl-1-cyclohexanol,

[0191] 0.5 parts by weight of Custer platinum catalyst,

[0192] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0193] 170 parts by weight of spherical nickel-coated graphite powder with a particle size of 50 μm.

[0194] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0195] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor and diluent are sequentially added into a disperser under vacuum (-95KPa) and stirred for 10 minutes (speed 1000 rpm) to obtain the electromagnetic shielding glue.

[0196] Comparative Example 1

[0197] The raw material composition of the base rubber is as follows:

[0198] 70 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15 wt%,

[0199] 30 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0200] 5 parts by weight of hexamethyldisilazane,

[0201] 3 parts by weight of deionized water.

[0202] The preparation method of the base glue comprises the following steps:

[0203] a) Add the branched vinyl silicone oil, hexamethyldisilazane and deionized water into a kneader and stir for 20 minutes;

[0204] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 3h;

[0205] c). Cool to room temperature to obtain the base glue.

[0206] The raw materials of electromagnetic shielding glue are as follows:

[0207] 80 parts by weight of base glue,

[0208] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0209] 2 parts by weight of terminal hydrogenated silicone oil, with a hydrogen content of 0.28wt% and a viscosity of 35mPa·s,

[0210] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0211] 0.01 parts by weight of the inhibitor 3-methyl-1-butyn-3-ol,

[0212] 0.5 parts by weight of Custer platinum catalyst,

[0213] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0214] 150 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0215] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0216] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor and diluent are sequentially added into a disperser and stirred for 10 minutes (speed 1000 rpm) under vacuum (-95KPa) to obtain the electromagnetic shielding glue.

[0217] Comparative Example 2

[0218] The raw material composition of the base rubber is as follows:

[0219] 70 parts by weight of vinyl-terminated silicone oil, with a vinyl content of 0.15 wt%,

[0220] 30 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0221] 5 parts by weight of tetramethyldivinylsilazane,

[0222] 3 parts by weight of deionized water.

[0223] The preparation method of the base glue comprises the following steps:

[0224] a) Add the vinyl-terminated silicone oil, tetramethyldivinylsilazane and deionized water into a kneader and stir for 20 minutes;

[0225] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 3h;

[0226] c). Cool to room temperature to obtain the base glue.

[0227] The raw materials of electromagnetic shielding glue are as follows:

[0228] 80 parts by weight of base glue,

[0229] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0230] 2 parts by weight of terminal hydrogenated silicone oil, with a hydrogen content of 0.28wt% and a viscosity of 35mPa·s,

[0231] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0232] 0.01 parts by weight of the inhibitor 3-methyl-1-butyn-3-ol,

[0233] 0.5 parts by weight of Custer platinum catalyst,

[0234] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0235] 150 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0236] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0237] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor and diluent are sequentially added into a disperser and stirred for 10 minutes (speed 1000 rpm) under vacuum (-95KPa) to obtain the electromagnetic shielding glue.

[0238] Comparative Example 3

[0239] The raw material composition of the base rubber is as follows:

[0240] 70 parts by weight of vinyl silicone oil, with a vinyl content of 0.15wt% and a viscosity of 4000mPa·s,

[0241] 30 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0242] 5 parts by weight of tetramethyldivinylsilazane,

[0243] 3 parts by weight of deionized water.

[0244] The preparation method of the base glue comprises the following steps:

[0245] a) Add the side vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 20 minutes;

[0246] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 3h;

[0247] c). Cool to room temperature to obtain the base glue.

[0248] The raw materials of electromagnetic shielding glue are as follows:

[0249] 80 parts by weight of base glue,

[0250] 2 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0251] 2 parts by weight of terminal hydrogenated silicone oil, with a hydrogen content of 0.28wt% and a viscosity of 35mPa·s,

[0252] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0253] 0.01 parts by weight of the inhibitor 3-methyl-1-butyn-3-ol,

[0254] 0.5 parts by weight of Custer platinum catalyst,

[0255] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0256] 150 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0257] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0258] The above-mentioned base glue, nickel-coated graphite powder, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, thickener, catalyst, inhibitor and diluent are sequentially added into a disperser and stirred for 10 minutes (speed 1000 rpm) under vacuum (-95KPa) to obtain the electromagnetic shielding glue.

[0259] Comparative Example 4

[0260] The raw material composition of the base rubber is as follows:

[0261] 70 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15 wt%,

[0262] 30 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0263] 5 parts by weight of tetramethyldivinylsilazane,

[0264] 3 parts by weight of deionized water.

[0265] The preparation method of the base glue comprises the following steps:

[0266] a) Add the branched vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 20 minutes;

[0267] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 3h;

[0268] c). Cool to room temperature to obtain the base glue.

[0269] The raw materials of electromagnetic shielding glue are as follows:

[0270] 80 parts by weight of base glue,

[0271] 4 parts by weight of hydrogenated silicone oil, with a hydrogen content of 0.36wt% and a viscosity of 20mPa·s,

[0272] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0273] 0.01 parts by weight of the inhibitor 3-methyl-1-butyn-3-ol,

[0274] 0.5 parts by weight of Custer platinum catalyst,

[0275] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0276] 150 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0277] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0278] The above-mentioned base glue, nickel-coated graphite powder, side hydrogenated silicone oil, tackifier, catalyst, inhibitor and diluent are sequentially added into a disperser and stirred for 10 minutes (speed 1000 rpm) under vacuum (-95KPa) to obtain the electromagnetic shielding glue.

[0279] Comparative Example 5

[0280] The raw material composition of the base rubber is as follows:

[0281] 70 parts by weight of branched vinyl silicone oil, with a vinyl content of 0.15 wt%,

[0282] 30 parts by weight of fumed silica, with a specific surface area of ​​200 m 2 / g,

[0283] 5 parts by weight of tetramethyldivinylsilazane,

[0284] 3 parts by weight of deionized water.

[0285] The preparation method of the base glue comprises the following steps:

[0286] a) Add the branched vinyl silicone oil, tetramethyl divinyl silazane and deionized water into a kneader and stir for 20 minutes;

[0287] b) Add white carbon black to the mixture obtained in step a) in batches, raise the temperature to 120°C and stir in vacuum (-95KPa) for 3h;

[0288] c). Cool to room temperature to obtain the base glue.

[0289] The raw materials of electromagnetic shielding glue are as follows:

[0290] 80 parts by weight of base glue,

[0291] 4 parts by weight of terminal hydrogenated silicone oil, with a hydrogen content of 0.28 wt% and a viscosity of 20 mPa·s

[0292] 1 part by weight of the adhesion promoter γ-methacryloxypropyltrimethoxysilane,

[0293] 0.01 parts by weight of the inhibitor 3-methyl-1-butyn-3-ol,

[0294] 0.5 parts by weight of Custer platinum catalyst,

[0295] 20 parts by weight of diluent octamethylcyclotetrasiloxane,

[0296] 150 parts by weight of spherical nickel-coated graphite powder with a particle size of 120 μm.

[0297] The preparation method of electromagnetic shielding adhesive comprises the following steps:

[0298] The above-mentioned base glue, nickel-coated graphite powder, end-hydrogenated silicone oil, tackifier, catalyst, inhibitor and diluent are sequentially added into a disperser and stirred for 10 minutes (speed 1000 rpm) under vacuum (-95KPa) to obtain the electromagnetic shielding glue.

[0299] The electromagnetic shielding adhesives prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to the following performance tests:

[0300] Hardness is measured according to GB / T531.1-2008 Test method for indentation hardness of vulcanized rubber or thermoplastic rubber

[0301] Tensile strength and elongation at break are based on GBT 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber;

[0302] The tear strength test is based on GBT529-2008 Determination of tear strength of vulcanized rubber or thermoplastic rubber;

[0303] Volume resistivity was determined according to MIL-DTL-83528C-2001;

[0304] The electromagnetic shielding effectiveness is measured according to GB / T 30142-2013 Shielding effectiveness measurement method of planar electromagnetic shielding materials;

[0305] The compression set is tested according to GBT 7759.1-2015 Determination of compression permanent set of vulcanized rubber or thermoplastic rubber.

[0306] The specific test results are shown in Table 1 and Table 2.

[0307] Table 1 Performance test results of electromagnetic shielding adhesives prepared in Examples 1-5

[0308]

[0309]

[0310] Table 2 Performance test results of electromagnetic shielding adhesives prepared in Comparative Examples 1-5

[0311]

[0312] From the results in Table 1 and Table 2, it can be seen that the comprehensive performance of the electromagnetic shielding adhesive in the embodiment of the present invention is significantly better than that of the electromagnetic shielding adhesive prepared in Comparative Examples 1-5, among which the tensile strength, elongation at break, volume resistivity, shielding effectiveness and compression deformation are all very excellent. However, the various performances in Comparative Examples 1-5 are relatively poor, and the compression deformation is relatively large, which means that it has undergone relatively large permanent deformation, relatively poor resilience, and the electromagnetic shielding effectiveness has significantly decreased after experiencing compression deformation, which will affect the use of electronic equipment.

[0313] Compared with Example 1, Comparative Example 1 uses hexamethyldisilazane to replace tetramethyldivinylsilazane in Example 1, resulting in that the various properties of the electromagnetic shielding adhesive obtained are worse than those of Example 1. This is because the modification of white carbon black by vinyl-containing silazane can graft vinyl groups on the surface of white carbon black to participate in the cross-linking reaction, thereby providing more cross-linking points and making the cross-linking network denser, thereby making the resilience and deformation resistance stronger and the electromagnetic shielding performance better.

[0314] Compared with Example 1, Comparative Examples 2 and 3 use terminal vinyl silicone oil and side vinyl silicone oil to replace the branched vinyl silicone oil in Example 1, respectively, resulting in that the various properties of the electromagnetic shielding adhesives obtained in Comparative Examples 2-3 are worse than those in Example 1. This is because the branched vinyl silicone oil prepared by the present invention has a unique branched molecular chain structure, which can more effectively improve the crosslinking density of the colloid and enhance the strength of the crosslinking network, thereby improving the mechanical properties of the colloid, and at the same time, it also has a very obvious help for the resilience and compression deformation of the colloid, thereby effectively ensuring the electromagnetic shielding effectiveness and allowing the electronic equipment to maintain long-term normal use.

[0315] Compared with Example 1, Comparative Examples 4 and 5 use side hydrogen-containing silicone oil and end hydrogen-containing silicone oil to replace the end hydrogen-containing silicone oil in Example 1, respectively, resulting in that the electromagnetic shielding adhesives obtained in Comparative Examples 4-5 have various properties worse than those in Example 1. This is because the addition of end hydrogen-containing silicone oil can provide more reactive groups, making the cross-linked network denser, which can effectively increase the cross-linking density of the system, thereby improving the resilience and deformation resistance, and making the electromagnetic shielding performance better.

[0316] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0317] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A high resilience electromagnetic shielding adhesive, characterized in that: It is prepared from raw materials including the following components: 70-100 parts by weight of base glue, 1-10 parts by weight of side hydrogenated silicone oil, 1-5 parts by weight of end-side hydrogenated silicone oil, 1-5 parts by weight of a tackifier, 0.01-0.03 parts by weight of an inhibitor, 0.1-0.5 parts by weight of a platinum catalyst, 10-30 parts by weight of diluent, 150-200 parts by weight of conductive filler; The gum base is prepared from raw materials including the following components: 60-90 parts by weight of branched vinyl silicone oil, 20-35 parts by weight of fumed silica, 1-7 parts by weight of tetramethyldivinylsilazane, 1-5 parts by weight of water; The structure of the branched vinyl silicone oil is: ； The branched vinyl silicone oil has a viscosity of 8000 mPa·s to 30000 mPa·s and a vinyl content of 0.1 wt% to 0.4 wt%; The viscosity of the side hydrogen-containing silicone oil is 10mPa·s to 200mPa·s, and the hydrogen content thereof is 0.18wt% to 0.75wt%; The viscosity of the end-side hydrogen-containing silicone oil is 30 mPa·s to 100 mPa·s, and the hydrogen content thereof is 0.1 wt % to 1 wt %.

2. The high resilience electromagnetic shielding adhesive according to claim 1, characterized in that: The branched vinyl silicone oil is prepared by a hydrosilylation reaction of a vinyl-terminated silicone oil and a second-side hydrogen-containing silicone oil under the action of a platinum catalyst, and the reaction formula is as follows: 。 3. The high resilience electromagnetic shielding adhesive according to claim 2, characterized in that: The vinyl content of the vinyl-terminated silicone oil is 0.2wt%-0.6wt%, the viscosity of the second side hydrogen-containing silicone oil is 80mPa·s-500mPa·s, and the hydrogen content is 0.05wt%-0.36wt%; and / or, The mass ratio of the vinyl-terminated silicone oil to the second-side hydrogen-containing silicone oil is 10-15:

1.

4. The high resilience electromagnetic shielding adhesive according to claim 2, characterized in that: The vinyl content of the vinyl-terminated silicone oil is 0.4wt%-0.5wt%, the viscosity of the second side hydrogen-containing silicone oil is 100mPa·s-200mPa·s, and the hydrogen content is 0.08wt%-0.12wt%; and / or, The mass ratio of the vinyl-terminated silicone oil to the hydrogen-containing silicone oil is 12 to 14:1; and / or, The branched vinyl silicone oil has a viscosity of 9000 mPa·s to 15000 mPa·s, and a vinyl content of 0.1 wt % to 0.2 wt %.

5. The high resilience electromagnetic shielding adhesive according to any one of claims 1 to 4, characterized in that: The preparation method of the branched vinyl silicone oil comprises the following steps: Add the second side hydrogen-containing silicone oil, platinum catalyst and solvent into the reaction bottle, stir evenly, then drop the end vinyl silicone oil, raise the temperature to 80°C to 95°C after the dropwise addition, and react for 1h to 3h to obtain the product.

6. The high resilience electromagnetic shielding adhesive according to any one of claims 1 to 4, characterized in that: The specific surface area of ​​the fumed silica is 100 m 2 / g-350m 2 / g.

7. The high resilience electromagnetic shielding adhesive according to any one of claims 1 to 4, characterized in that: The preparation method of the base glue comprises the following steps: The branched vinyl silicone oil, tetramethyldivinylsilazane and water are mixed, and the fumed silica is added in batches. The temperature is raised to 110° C.-130° C., vacuum stirred for 2 h-5 h, and cooled to obtain the base rubber.

8. The high resilience electromagnetic shielding adhesive according to any one of claims 1 to 4, characterized in that: The tackifier is selected from at least one of γ-methacryloxypropyl trimethoxysilane, γ-glycidyloxypropyl trimethoxysilane, vinyl tris (2-methoxyethoxy) silane, and 3-isocyanatopropyl triethoxysilane; and / or, The inhibitor is selected from at least one of 1-ethyn-1-cyclohexanol, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol and 3,6-dimethyl-1-heptyn-3-ol; and / or, The catalyst is selected from at least one of a Custer catalyst, chloroplatinic acid, a chloroplatinic acid-isopropanol complex, and a chloroplatinic acid-divinyltetramethyldisiloxane complex; and / or, The diluent is selected from at least one of isopropyl alcohol, ethanol, acetone, butanone, kerosene, octamethylcyclotetrasiloxane, octamethyltrisiloxane, dimethyl carbonate and decamethyltetrasiloxane; and / or, The conductive filler is nickel-coated graphite powder, and its particle size is 20µm-150µm.

9. The high resilience electromagnetic shielding adhesive according to any one of claims 1 to 4, characterized in that: The viscosity of the side hydrogenated silicone oil is 15mPa·s-25mPa·s, and the hydrogen content thereof is 0.3wt%-0.4wt%; and / or, The viscosity of the end-side hydrogenated silicone oil is 30 mPa·s-40 mPa·s, and the hydrogen content thereof is 0.2 wt%-0.35 wt%.

10. A method for preparing the high resilience electromagnetic shielding adhesive according to any one of claims 1 to 9, characterized in that: The steps include: The base glue, conductive filler, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, tackifier, catalyst, inhibitor and diluent are sequentially added into a disperser and stirred in vacuum for 10 min-30 min to obtain the high resilience electromagnetic shielding glue.

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