Highly thixotropic insulating adhesive and preparation method therefor

Abstract

The present invention relates to the technical field of high polymer materials. Disclosed are a highly thixotropic insulating adhesive and a preparation method therefor. The highly thixotropic insulating adhesive creatively generates a highly thixotropic insulating adhesive framework. By means of the molecular acting force between a hydroxyl structure and a dimethylamino structure in the framework structure, high thixotropy is improved, and a more excellent insulating effect is achieved in the case of a thin coating layer. In addition, the present invention further provides a method for preparing the highly thixotropic insulating adhesive. The preparation method has the characteristics of simple steps and a low cost.

Description

A high thixotropic insulating adhesive and preparation method thereof Technical Field

[0001] The embodiments of the present application relate to the technical field of polymer materials, and in particular to a highly thixotropic insulating adhesive and a preparation method thereof. Background Art

[0002] In today's electronic age, various electrical devices continuously generate various electromagnetic radiations. If these radiations are not controlled, they can interfere with each other, leading to device malfunction or even more serious consequences. Therefore, many components need to shield these electromagnetic radiations, or even shield the electromagnetic radiation they generate themselves. The common solution is to use metal shielding covers, but these are costly, complex, and bulky. An alternative is to use electromagnetic shielding coatings. However, since electromagnetic shielding coatings are typically conductive, insulation measures are required between them and the target components.

[0003] Currently, the industry typically uses insulating adhesives for insulation, but these adhesives present several challenges. For example, to ensure effective insulation in the workplace, the film thickness typically needs to be at least 100μm, which presents challenges with film thickness. Furthermore, since most components are rectangular, the thixotropic index of the insulating adhesive is a critical factor. A low thixotropic index results in poor adhesion to sharp corners, resulting in demanding application procedures and reduced product yield.

[0004] In summary, how to provide an insulating adhesive with a high thixotropic index and capable of achieving functionality at a low thickness is a problem that relevant technicians in this field need to solve.

[0005] Summary of the Invention

[0006] In order to solve the above problems, the first aspect of the present application aims to provide a highly thixotropic insulating adhesive;

[0007] The second aspect of the present application aims to provide a method for preparing a highly thixotropic insulating adhesive.

[0008] In order to achieve the above object, the present invention provides the following technical solutions:

[0009] A highly thixotropic insulating adhesive, comprising a highly thixotropic insulating adhesive skeleton having the following structural formula (I):

[0010] Wherein, R represents one or more of C1-C6 straight or branched carbon chains.

[0011] Optionally, the highly thixotropic insulating adhesive skeleton having structural formula (I) is formed by polymerizing a first monomer and a second monomer, and the first monomer has the following structural formula (II):

[0012] The second monomer has the following structural formula (III):

[0013] Optionally, the following raw material components are included in parts by weight:

[0014] 0.05-0.15 parts of polyvinyl alcohol,

[0015] 6-8 parts of lower alcohol,

[0016] 33-36 parts of dimethylaminoethyl acrylate,

[0017] 10-12 parts of n-butyl acetate,

[0018] 12-15 parts of hydroxy acrylate,

[0019] 0.5-2 parts initiator,

[0020] 4-6 parts emulsifier,

[0021] 25-30 parts deionized water;

[0022] The high thixotropic insulating adhesive skeleton is formed by polymerizing the dimethylaminoethyl acrylate and the hydroxy acrylate.

[0023] Optionally, the lower alcohol includes at least one of methanol, ethanol, propanol, butanol and isomers thereof.

[0024] Optionally, the initiator includes at least one of ammonium sulfate, magnesium sulfate, barium sulfate or calcium sulfate.

[0025] Optionally, the emulsifier comprises glyceryl monostearate.

[0026] Optionally, the polyvinyl alcohol has a degree of polymerization of 1000-1500, a degree of alcoholysis of 52-55 mole / %, and a viscosity of 4% aqueous solution of 4.0-6.0 mPa.S.

[0027] In a second aspect, a method for preparing the above-mentioned highly thixotropic insulating adhesive is provided, wherein the preparation method comprises:

[0028] Dimethylaminoethyl acrylate, hydroxy acrylate monomer and initiator are added into a reactor and heated to preliminarily obtain an insulating adhesive including the highly thixotropic insulating adhesive skeleton.

[0029] Optionally, before “adding dimethylaminoethyl acrylate, hydroxyacrylate monomer, and initiator into the reactor”, the preparation method further comprises:

[0030] Adding lower alcohol, n-butyl acetate and deionized water into a reactor and mixing them uniformly to form a mixed solution;

[0031] An emulsifier is added to the mixed solution and stirred evenly.

[0032] Optionally, after “heating to obtain the highly thixotropic insulating adhesive skeleton”, the preparation method further comprises:

[0033] Polyvinyl alcohol is added to the preliminarily obtained insulating adhesive, stirred evenly, and cooled to room temperature to obtain a highly thixotropic insulating adhesive.

[0034] Based on the above technical solutions, the present invention has the following technical effects:

[0035] 1. The present invention provides a highly thixotropic insulating adhesive that creatively creates a highly thixotropic insulating adhesive skeleton and utilizes the molecular forces between the hydroxyl groups and dimethylamine groups within the skeleton structure to enhance thixotropic properties. When the highly thixotropic insulating adhesive is in a static state, the nucleophilicity of the hydroxyl groups and the electrophilicity of the dimethylamine groups generate intermolecular forces between them. The hydroxyl and dimethylamine groups between the molecular chains attract each other, macroscopically increasing the static viscosity. This intermolecular force is also very small compared to the mechanical shear forces applied externally under stirring conditions, thereby ensuring fluidity under external forces. This ultimately improves the thixotropic properties of the product.

[0036] 2. The preparation method of the highly thixotropic insulating adhesive provided by the present invention obtains the target product, the highly thixotropic insulating adhesive skeleton, through the polymerization reaction of the monomers dimethylaminoethyl acrylate and hydroxy acrylate. The synthesis steps are simple and easy to operate.

[0037] 3. The high thixotropic insulating adhesive provided by the present invention has a high thixotropic insulating adhesive skeleton as its main active ingredient. The high thixotropic insulating adhesive skeleton provides the high thixotropic insulating adhesive with high thixotropic and insulating properties. In addition, the high thixotropic insulating adhesive can maintain good insulation ability when applied in a thin layer, effectively meeting the insulation requirements of electromagnetic shielding coatings. DETAILED DESCRIPTION

[0038] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to specific embodiments. The present invention provides preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0039] Before further describing the various embodiments of the compounds / compositions and methods of the present disclosure in more detail through exemplary descriptions, examples and results, it should be understood that the embodiments of the present disclosure are not limited in application to the details of the methods and compositions described in the following description. The description provided herein is for illustrative purposes only and is not to be interpreted in a limiting sense. The inventive concepts of the present disclosure are capable of other embodiments or can be practiced or implemented in various ways. Therefore, the language used herein is intended to give the broadest scope and meaning; and the embodiments are intended to be exemplary, not exhaustive, and are not intended to limit the present disclosure to these specific embodiments. Moreover, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered restrictive unless otherwise stated. In addition, in the following detailed description, many specific details are listed in order to provide a more thorough understanding of the present disclosure.

[0040] However, it is obvious to one skilled in the art that the embodiments of the present disclosure can be practiced without these specific details. In other cases, features well known to one skilled in the art have not been described in detail to avoid unnecessary complexity of the description. It is intended that all alternatives, replacements, modifications and equivalents obvious to one skilled in the art are included within the scope of the present disclosure. Based on the present disclosure, all compounds / compositions disclosed herein and their preparation methods, applications and uses can be prepared and implemented without undue experimentation.

[0041] Thus, while the compounds / compositions and methods of the present disclosure have been described with respect to specific embodiments, it will be apparent to those skilled in the art that variations may be made in the formulations, compounds or compositions and / or methods, as well as in the steps or order of steps of the methods described herein, without departing from the spirit and scope of the inventive concepts of the present disclosure.

[0042] As used herein, any reference to "one embodiment" or "an embodiment" means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase "in one embodiment" in multiple places in the specification are not necessarily all referring to the same embodiment.

[0043] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present disclosure shall have the meanings commonly understood by those of ordinary skill in the art. In addition, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0044] Example 1

[0045] Synthesis route of high thixotropic insulating adhesive skeleton:

[0046] In this embodiment, monomer (I) is dimethylaminoethyl acrylate, and monomer (II) is hydroxymethyl acrylate, wherein R represents a C1 carbon chain.

[0047] The synthesis steps of high thixotropic insulating adhesive containing high thixotropic insulating adhesive skeleton are as follows:

[0048] (1) In a 2 L glass three-necked flask, 60 g of ethanol, 100 g of n-butyl acetate, and 250 g of deionized water were mixed to form a mixed solution;

[0049] (2) Add 40 g of glyceryl monostearate into a glass container in proportion and stir evenly;

[0050] (3) Add 330 g of dimethylaminoethyl acrylate and 150 g of hydroxymethyl acrylate into a glass container, stir, and heat in a water bath to 60° C.; add 5 g of ammonium persulfate, and maintain the temperature under reflux and stirring for 120-160 minutes;

[0051] (4) Add 1g of polyvinyl alcohol, stir evenly, cool to room temperature, and store in a sealed container.

[0052] In step (3), dimethylaminoethyl acrylate and hydroxymethyl acrylate are used as monomers, and a polymerization reaction is generated under the action of an initiator represented by ammonium persulfate to generate a high thixotropic insulating adhesive skeleton, which provides the high thixotropic and insulating properties of the high thixotropic insulating adhesive; wherein the initiator can also be other alkaline earth metal persulfate salts, such as magnesium persulfate, barium persulfate or calcium persulfate, etc.

[0053] It should be noted that in other embodiments, the weight percentage of dimethylaminoethyl acrylate is preferably 35 parts, and the weight percentage of hydroxyacrylate is preferably 13 parts. The hydroxyacrylate can be at least one of methyl hydroxyacrylate, ethyl hydroxyacrylate, propyl hydroxyacrylate, and butyl hydroxyacrylate. This preparation method has the characteristics of simple steps and low cost.

[0054] In step (1), the mixed solution formed by mixing a lower alcohol represented by ethanol, n-butyl acetate, and deionized water can ensure that the raw materials will not be separated before and after polymerization and provide a certain viscosity. In addition, the lower alcohol provides good quick-drying performance when used by the user; wherein, the lower alcohol is preferably a monohydric alcohol, which can be at least one of methanol, ethanol, propanol, butanol, and isomers thereof.

[0055] In step (2), the emulsifier represented by glyceryl monostearate can provide better dispersion performance for the polymerization product, that is, the high thixotropic insulating adhesive skeleton, and also optimize the fluidity of the high thixotropic insulating adhesive.

[0056] In step (4), the thixotropy of the highly thixotropic insulating adhesive is further optimized by adding polyvinyl alcohol. In this embodiment, polyvinyl alcohol having the following properties is preferred: degree of polymerization of 1000-1500, degree of alcoholysis of 52-55 mole / %, and viscosity of 4% aqueous solution of 4.0-6.0 mPa.s.

[0057] Example 2

[0058] In this embodiment, monomer (I) is dimethylaminoethyl acrylate, and monomer (II) is n-butyl hydroxyacrylate, wherein R represents a C4 carbon chain.

[0059] (1) In a 2 L glass three-necked flask, 70 g of ethanol, 120 g of n-butyl acetate, and 300 g of deionized water were mixed to form a mixed solution;

[0060] (2) Add 60 g of glyceryl monostearate into a glass container in proportion and stir evenly;

[0061] (3) Add 360 g of dimethylaminoethyl acrylate and 150 g of n-butyl hydroxyacrylate into a glass container, stir, and heat in a water bath to 60° C.; add 15 g of ammonium persulfate, and maintain the temperature under reflux and stirring for 120-160 minutes;

[0062] (4) Add 0.8 g of polyvinyl alcohol, stir evenly, cool to room temperature, and store in a sealed container.

[0063] Example 3

[0064] In this embodiment, monomer (I) is dimethylaminoethyl acrylate, and monomer (II) is hydroxyethyl acrylate, wherein R represents a C4 carbon chain.

[0065] (1) In a 2 L glass three-necked flask, 80 g of propanol, 110 g of n-butyl acetate, and 280 g of deionized water were mixed to form a mixed solution;

[0066] (2) Add 50 g of glyceryl monostearate into a glass container in proportion and stir evenly;

[0067] (3) Add 350 g of dimethylaminoethyl acrylate and 120 g of hydroxyethyl acrylate into a glass container, stir, and heat in a water bath to 65° C.; add 15 g of ammonium persulfate, and maintain the temperature under reflux with stirring for 120-160 minutes;

[0068] (4) Add 1.5 g of polyvinyl alcohol, stir evenly, cool to room temperature, and store in a sealed container.

[0069] Example 4

[0070] In this embodiment, monomer (I) is dimethylaminoethyl acrylate, and monomer (II) is n-propyl hydroxyacrylate, wherein R represents a C3 carbon chain.

[0071] (1) In a 2 L glass three-necked flask, 60 g of ethanol, 110 g of n-butyl acetate, and 300 g of deionized water were mixed to form a mixed solution;

[0072] (2) Add 60 g of glyceryl monostearate into a glass container in proportion and stir evenly;

[0073] (3) Add 360 g of dimethylaminoethyl acrylate and 140 g of n-propyl hydroxyacrylate into a glass container, stir, and heat in a water bath to 60° C.; add 18 g of ammonium persulfate, and maintain the temperature under reflux with stirring for 120-160 minutes;

[0074] (4) Cool to room temperature and store in a sealed container.

[0075] 1. The high thixotropic insulating adhesive samples obtained in the above four examples were subjected to thixotropic index testing and compared with the thixotropic index of the typical commercially available insulating adhesives, the imported competitor A and the domestic competitor B. The following Table 1 shows the thixotropic index data of the samples of Examples 1-4 and the competitors:

[0076] Table 1 Thixotropic index of example samples and typical commercially available competitive products

[0077] 2. The highly thixotropic insulating adhesive samples obtained in Examples 1-4 were coated on a test substrate with a 50 μm adhesive layer using a coater. Competitive insulating adhesives A and B were coated on two test substrates with 50 μm and 100 μm adhesive layers, respectively, using a coater. All coated substrates were baked and cured at 120°C for 15 minutes, then powered on and immersed in artificial sweat to test the insulation ability of the adhesive layer under artificial sweat corrosion conditions. The test results are shown in Table 2:

[0078] Table 2 Insulation maintenance time of example samples and typical commercially available competitive products

[0079] It should be noted that the artificial sweat used in the test is configured according to "4.4 Acid Test Solution" in the GB / T 3922 standard.

[0080] From Table 1, the thixotropic index of the high thixotropic insulating adhesives of Examples 1-4 are all above 7.3, and are significantly higher than typical commercially available competing products. The main reason for this is that Examples 1-4 creatively utilize the molecular forces between the hydroxyl structure and the dimethylamino structure in the skeleton structure to improve the high thixotropic performance. In the static state of the high thixotropic insulating adhesive, the nucleophilicity of the hydroxyl group and the electrophilicity of the dimethylamino group cause an intermolecular force to be generated between the two, and the hydroxyl and dimethylamino groups between the molecular chains attract each other, which macroscopically increases the viscosity at rest. This intermolecular force is very small compared to the mechanical shear force applied externally under conditions such as stirring, thereby ensuring fluidity under external force, and ultimately improving the thixotropic performance of the product. The low thixotropic index leads to poor glue attachment ability at sharp corners, especially when it needs to be applied to electromagnetic shielding coatings such as rectangular blocks. Insulating adhesives with a high thixotropic index can reduce the difficulty of use and improve the yield rate when used on electromagnetic shielding coatings.

[0081] Furthermore, Table 2 shows that the highly thixotropic insulating adhesive samples of Examples 1-4 exhibit excellent corrosion resistance and insulation performance at a 50 μm coating thickness, significantly outperforming the insulation performance of Competitors A and B at 100 μm coating thickness. This demonstrates that the highly thixotropic insulating adhesives of Examples 1-4 can meet the insulation requirements of a working environment even with a thin coating thickness.

[0082] The above description is merely an example and illustration of the structure of the present invention. Although the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications and improvements without departing from the scope of the present invention, and such obvious alternatives are all within the scope of protection of the present invention.

Claims

1. A highly thixotropic insulating adhesive, characterized in that: The highly thixotropic insulating adhesive contains a highly thixotropic insulating adhesive skeleton, and the highly thixotropic insulating adhesive skeleton has the following structural formula (I): Wherein, R represents one or more of C1-C6 straight or branched carbon chains.

2. The highly thixotropic insulating adhesive according to claim 1, characterized in that: The highly thixotropic insulating adhesive skeleton having structural formula (I) is formed by polymerizing a first monomer and a second monomer, wherein the first monomer has the following structural formula (II): The second monomer has the following structural formula (III):

3. The highly thixotropic insulating adhesive according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 0.05-0.15 parts of polyvinyl alcohol, 6-8 parts of lower alcohol, 33-36 parts of dimethylaminoethyl acrylate, 10-12 parts of n-butyl acetate, 12-15 parts of hydroxy acrylate, 0.5-2 parts initiator, 4-6 parts emulsifier, 25-30 parts deionized water; The high thixotropic insulating adhesive skeleton is formed by polymerizing the dimethylaminoethyl acrylate and the hydroxy acrylate.

4. The highly thixotropic insulating adhesive according to claim 3, characterized in that: The lower alcohol includes at least one of methanol, ethanol, propanol, butanol and isomers thereof.

5. The highly thixotropic insulating adhesive according to claim 3, characterized in that: The initiator includes at least one of ammonium persulfate, magnesium persulfate, barium persulfate or calcium persulfate.

6. The highly thixotropic insulating adhesive according to claim 3, characterized in that: The emulsifier includes glyceryl monostearate.

7. The highly thixotropic insulating adhesive according to claim 3, characterized in that: The polyvinyl alcohol has a polymerization degree of 1000-1500, an alcoholysis degree of 52-55 mole / %, and a 4% aqueous solution viscosity of 4.0-6.0 mPa.S.

8. A method for preparing the highly thixotropic insulating adhesive according to any one of claims 1 to 7, characterized in that: The preparation method comprises: Dimethylaminoethyl acrylate, hydroxy acrylate monomer and initiator are added into a reactor and heated to preliminarily obtain an insulating adhesive including the highly thixotropic insulating adhesive skeleton.

9. The method for preparing a highly thixotropic insulating adhesive according to claim 8, characterized in that: Before "adding dimethylaminoethyl acrylate, hydroxy acrylate monomer, and initiator into the reactor", the preparation method further comprises: Adding lower alcohol, n-butyl acetate and deionized water into a reactor and mixing them uniformly to form a mixed solution; An emulsifier is added to the mixed solution and stirred evenly.

10. The method for preparing a highly thixotropic insulating adhesive according to claim 9, characterized in that: After "heating to obtain the highly thixotropic insulating adhesive skeleton", the preparation method further comprises: Polyvinyl alcohol is added to the preliminarily obtained insulating adhesive, stirred evenly, and cooled to room temperature to obtain a highly thixotropic insulating adhesive.

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