A one-component epoxy sealant, its preparation method, and its application.

Abstract

This invention relates to the field of adhesive technology, and particularly to a one-component epoxy sealant and its preparation method. By weight, it comprises the following components: 10-20 parts solid epoxy resin, 20-35 parts low-viscosity epoxy resin, 10-15 parts rubber-modified epoxy resin, 10-13 parts cashew phenol epoxy reactive diluent, 32-35 parts acid anhydride mixture, and 3-5 parts modified imidazole. The one-component epoxy sealant of this invention is characterized by its ease of use as a single component, excellent waterproofing, good sealing performance, low shrinkage, and high bonding strength. It effectively ensures the sealing and protection requirements of sensors within wearable smart electronic products, and is also suitable for sealing and bonding various wearable smart electronic product housings to associated difficult-to-bond materials, demonstrating good applicability.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, and in particular to a one-component epoxy sealant, its preparation method, and its application. Background Technology

[0002] Wearable smart electronic products, as an emerging technology, are widely used in fields such as health, medicine, and sports, primarily through various sensors and software technologies to monitor human physiological functions. Wearable smart electronic products are developing towards multi-functionality and miniaturization, with the micro-assembly technology of various key components also advancing rapidly. Simultaneously, sensor technology is also developing towards high precision, multi-dimensionality, and virtual multi-functionality. Sealant is used to seal and protect wearable smart electronic products and related sensor components, resulting in good processability, high adhesive strength, and effectively improving the functionality, practicality, and reliability of wearable smart electronic products.

[0003] Most commercially available sealants currently suffer from problems such as complex operation, poor waterproof performance, poor sealing performance, large shrinkage, and low bonding strength, which cannot meet the high-performance requirements brought about by the current development of wearable product technology towards multi-functionality and miniaturization. Summary of the Invention

[0004] To address the aforementioned technical problems in the prior art, this invention provides a one-component epoxy sealant and its preparation method.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] A first aspect of the present invention is to provide a one-component epoxy sealant, comprising, by weight parts:

[0007] 10-20 parts solid epoxy resin, 20-35 parts low-viscosity epoxy resin, 10-15 parts rubber-modified epoxy resin, 10-13 parts cashew phenol epoxy reactive diluent, 32-35 parts acid anhydride mixture, and 3-5 parts modified imidazole.

[0008] Based on the above technical solution, the present invention can also be improved in the following ways:

[0009] Furthermore, the solid epoxy resin is a solid epoxy resin with a molecular weight of 1345-1395, an epoxy equivalent of 800-835 g / eq, and a softening point of 87-95°C.

[0010] Furthermore, the solid epoxy resin is prepared by the following method: 71-72 parts by mass of epoxy resin and 28-29 parts by mass of bisphenol A are added to a reaction vessel, heated to 140-160°C, and stirred at 10 RPM for 1-2 hours until completely dissolved; the temperature is lowered to 95-105°C, and 0.05-0.1 parts by mass of catalyst are added while maintaining the stirring speed at 10 RPM; the temperature is then raised to 185-195°C, a vacuum is drawn, and the stirring speed is set to 30 RPM for 2-3 hours to obtain the solid epoxy resin.

[0011] Furthermore, the epoxy resin is a bisphenol A type epoxy resin with a molecular weight of 338-346 and an epoxy equivalent of 188-198 g / eq; the bisphenol A propane has a molecular weight of 216-228 and a melting point of 158-159°C; and the catalyst is ethyltriphenylphosphine bromide with a molecular weight of 265-371 and a melting point of 204-207°C.

[0012] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the synthesis mechanism of the solid epoxy resin is that the oxygen atom of the epoxy group in the epoxy resin undergoes a Michael addition reaction with the hydroxyl group in bisphenol A propane under the catalysis of ethyltriphenylphosphine bromide; the solid epoxy resin has a large molecular weight, which can increase the flexibility and sealing of the system, and at the same time has good waterproof performance; the benzene ring hybrid structure with molecular linkages has excellent thermal stability and low shrinkage performance.

[0013] Furthermore, the epoxy resin is HBEL-123 produced by Dongying Hebang Chemical Co., Ltd.

[0014] The beneficial effects of adopting the above-mentioned further technical solution are that the epoxy resin HBEL-123 has excellent reactivity and bonding strength, which is conducive to further improving the bonding strength and sealing performance of solid epoxy resin.

[0015] Furthermore, the bisphenol A propane is bisphenol A propane produced by Huangshan Shanfu Chemical Co., Ltd.

[0016] Furthermore, the catalyst is ethyltriphenylphosphine bromide produced by Shanghai Yuanye Biotechnology Co., Ltd., which has the structural formula shown in Formula I:

[0017]

[0018] The beneficial effects of adopting the above-mentioned further technical solution are as follows: compared with other phosphorus-based catalysts and imidazole catalysts, the ethyltriphenylphosphine bromide exhibits high catalytic efficiency, stable acceleration of reaction rate, and good heat resistance and flexibility of the product.

[0019] Furthermore, the low-viscosity epoxy resin is a bisphenol F type epoxy resin with a viscosity of 800-1500 mPa·s at 25°C and an epoxy equivalent of 155-165 g / eq; the rubber-modified epoxy resin is a nano-core-shell rubber-modified epoxy resin with a viscosity of 6000-9000 mPa·s at 50°C and an epoxy equivalent of 260-275 g / eq; the cashew phenol epoxy reactive diluent is a cashew phenol modified epoxy reactive diluent with a viscosity of 90-200 mPa·s at 25°C and an epoxy equivalent of 250-300 g / eq; and the modified imidazole is an imidazole adduct with an average particle size of 2-4 μm and a reaction temperature of 100°C.

[0020] Furthermore, the low-viscosity epoxy resin is HBEL-153 produced by Dongying Hebang Chemical Co., Ltd.

[0021] The beneficial effects of adopting the above-mentioned further technical solution are that the low viscosity epoxy resin has the characteristics of low viscosity, high bonding strength and low shrinkage.

[0022] Furthermore, the rubber-modified epoxy resin is MX267 manufactured by Kaneka Corporation of Japan.

[0023] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the rubber-modified epoxy resin is a nano-core-shell rubber-modified epoxy resin toughening agent, the nano-core-shell rubber is uniformly dispersed in the epoxy resin, and has excellent toughness, heat resistance and impact resistance.

[0024] Furthermore, the cashew phenol epoxy reactive diluent is LITE513DF manufactured by Cardley Chemicals, Inc., USA, which has the structural formula shown in Formula II:

[0025]

[0026] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the cashew phenol epoxy reactive diluent has long aliphatic side chains, exhibiting strong hydrophobicity, good water resistance, and good flexibility.

[0027] Furthermore, the imidazole adduct is PN-23J manufactured by Ajinomoto Co., Ltd. of Japan.

[0028] The beneficial effect of adopting the above-mentioned further scheme is that the imidazole adduct can accelerate the reaction rate of the acid anhydride mixture and epoxy resin, and the product has the characteristics of low shrinkage, good heat resistance, and good water resistance.

[0029] Furthermore, the anhydride mixture is prepared by the following method: 18-20 parts by mass of dodecenyl succinic anhydride, 79-80 parts by mass of methyl hexahydrophthalic anhydride, and 1-3 parts by mass of glycerol are sequentially added to a stirred tank, and the mixture is stirred for 0.5-1 hour under nitrogen protection at a speed of 10 RPM to obtain the anhydride mixture.

[0030] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the obtained anhydride mixture has a longer end group molecular chain, which can increase the flexibility and sealing of the system, while also having good water resistance and adhesion properties; glycerol, as a molecular chain transfer agent, has good reaction control performance and reduces the volume shrinkage effect caused by molecular cross-linking of the system.

[0031] Furthermore, the dodecenylsuccinic anhydride is an aliphatic anhydride with a molecular weight of 262-270 and an acid value of 395-425 mgKOH / g; the methylhexahydrophthalic anhydride is an anhydride compound with a molecular weight of 164-172 and an acid value of 640-650 mgKOH / g.

[0032] Furthermore, the dodecenyl succinic anhydride is CA-I-05 produced by Guangdong Huajinda New Materials Co., Ltd.

[0033] Furthermore, the methylhexahydrophthalic anhydride is HNA-100 manufactured by Hitachi, Ltd. of Japan.

[0034] Furthermore, the glycerol mentioned is glycerol produced by Henan Changyuan Chemical Products Co., Ltd.

[0035] The second aspect of the present invention is to provide a method for preparing the above-mentioned one-component epoxy sealant, comprising the following steps: according to the mass parts, solid epoxy resin, low viscosity epoxy resin, rubber modified epoxy resin, cashew phenol epoxy reactive diluent, acid anhydride mixture and modified imidazole are sequentially added into a mixing tank, vacuum is drawn, the rotation speed is set to 30 RPM, and the mixture is stirred for 3 to 4 hours to obtain the one-component epoxy sealant.

[0036] Another aspect of the present invention is to provide the application of the above-mentioned one-component epoxy sealant in wearable smart electronic products.

[0037] Compared with the prior art, the present invention has the following technical effects:

[0038] The single-component epoxy sealant of this invention features easy operation and effectively meets the diverse process requirements of wearable smart electronic products; it has good waterproof performance, good sealing performance, and low shrinkage performance, effectively ensuring the sealing and protection requirements of sensors inside wearable smart electronic products; it has high bonding strength and is suitable for sealing and bonding various wearable smart electronic product shells to related difficult-to-bond materials, thus having good applicability. Detailed Implementation

[0039] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0040] Example 1

[0041] a. By mass parts: 710g of epoxy resin HBEL-123 and 290g of bisphenol A propane were added to a reaction vessel, heated to 140℃, and stirred at 10 RPM for 1.5 hours until completely dissolved; cooled to 95℃, and under the same stirring conditions (10 RPM), 1g of ethyltriphenylphosphine bromide was added; then heated to 185℃, vacuumed, and stirred at 30 RPM for 3 hours to obtain solid epoxy resin;

[0042] b. By mass parts: 190g of dodecenyl succinic anhydride CA-I-05, 790g of methyl hexahydrophthalic anhydride HNA-100, and 20g of glycerol were added sequentially into a stirred tank. Under nitrogen protection, the stirring speed was set to 10 RPM and stirred for 1 hour to obtain an acid-anhydride mixture.

[0043] c. By mass parts: 100g of solid epoxy resin, 350g of low viscosity epoxy resin HBEL-153, 100g of rubber modified epoxy resin MX267, 100g of cashew phenol epoxy reactive diluent LITE513DF, 350g of acid anhydride mixture, and 50g of modified imidazole PN-23J are added sequentially into a mixing tank. Under vacuum conditions, the speed is set to 30RPM and stirred for 3 hours to obtain the sealant.

[0044] Example 2

[0045] a. By mass parts: 720g of epoxy resin HBEL-123 and 280g of bisphenol A propane were added to a reaction vessel, heated to 150℃, and stirred at 10 RPM for 1 hour until completely dissolved; cooled to 100℃, and 0.5g of ethyltriphenylphosphine bromide was added under the same stirring conditions; heated to 190℃, and stirred at 30 RPM under vacuum for 2 hours to obtain solid epoxy resin;

[0046] b. By mass parts: 200g of dodecenyl succinic anhydride CA-I-05, 800g of methyl hexahydrophthalic anhydride HNA-100, and 10g of glycerol were added sequentially into a stirred tank. Under nitrogen protection, the stirring speed was set to 10 RPM and stirred for 0.5 hours to obtain an acid-anhydride mixture.

[0047] c. By mass parts: 150g of solid epoxy resin, 200g of low viscosity epoxy resin HBEL-153, 150g of rubber modified epoxy resin MX267, 130g of cashew phenol epoxy reactive diluent LITE513DF, 330g of acid anhydride mixture, and 40g of modified imidazole PN-23J are added sequentially into a mixing tank. Under vacuum conditions, the speed is set to 30RPM and stirred for 3 hours to obtain the sealant.

[0048] Example 3

[0049] a. By mass parts: 710g of epoxy resin HBEL-123 and 290g of bisphenol A propane were added to a reaction vessel, heated to 160℃, and stirred at 10 RPM for 2 hours until completely dissolved; the temperature was lowered to 105℃, and 1g of ethyltriphenylphosphine bromide was added under the same stirring conditions (10 RPM); the temperature was then raised to 195℃, and stirred at 30 RPM under vacuum for 3 hours to obtain solid epoxy resin;

[0050] b. By mass parts: 180g of dodecenyl succinic anhydride CA-I-05, 790g of methyl hexahydrophthalic anhydride HNA-100, and 30g of glycerol were added sequentially into a stirred tank. Under nitrogen protection, the stirring speed was set to 10 RPM and stirred for 1 hour to obtain an acid-anhydride mixture.

[0051] c. By mass parts: 200g of solid epoxy resin, 250g of low viscosity epoxy resin HBEL-153, 100g of rubber modified epoxy resin MX267, 100g of cashew phenol epoxy reactive diluent LITE513DF, 320g of acid anhydride mixture, and 30g of modified imidazole PN-23J are added sequentially into a mixing tank. Under vacuum conditions, the speed is set to 30RPM and stirred for 4 hours to obtain the sealant.

[0052] Comparative Example 1

[0053] a. By mass parts: 180g of dodecenyl succinic anhydride CA-I-05, 790g of methyl hexahydrophthalic anhydride HNA-100, and 30g of glycerol were added sequentially into a stirred tank. Under nitrogen protection, the stirring speed was set to 10 RPM and stirred for 1 hour to obtain an acid-anhydride mixture.

[0054] c. By mass parts: 160g of epoxy resin HBEL-123, 250g of low viscosity epoxy resin HBEL-153, 100g of rubber-modified epoxy resin MX267, 100g of cashew phenol epoxy reactive diluent LITE513DF, 360g of acid anhydride mixture, and 30g of modified imidazole PN-23J are added sequentially into a mixing tank. Under vacuum conditions, the speed is set to 30RPM and stirred for 3 hours to obtain the sealant.

[0055] Comparative Example 2

[0056] a. By mass parts: 710g of epoxy resin HBEL-123 and 290g of bisphenol A propane were added to a reaction vessel, heated to 160℃, and stirred at 10 RPM for 2 hours until completely dissolved; the temperature was lowered to 95℃, and 1g of ethyltriphenylphosphine bromide was added under the same stirring conditions; the temperature was then raised to 195℃, and stirred at 30 RPM under vacuum for 3 hours to obtain solid epoxy resin;

[0057] b. By mass parts: 180g of dodecenyl succinic anhydride CA-I-05, 790g of methyl hexahydrophthalic anhydride HNA-100, and 30g of glycerol were added sequentially into a stirred tank. Under nitrogen protection, the stirring speed was set to 10 RPM and stirred for 1 hour to obtain an acid-anhydride mixture.

[0058] c. By mass parts: 200g of solid epoxy resin, 250g of low viscosity epoxy resin HBEL-153, 100g of rubber modified epoxy resin MX267, 100g of carbon 12-14 alkyl glycidyl ether (748), 320g of acid anhydride mixture, and 30g of modified imidazole PN-23J are added sequentially into a mixing tank. Under vacuum conditions, the speed is set to 30RPM and stirred for 4 hours to obtain the sealant.

[0059] Comparative Example 3

[0060] a. By mass parts: 710g of epoxy resin HBEL-123 and 290g of bisphenol A propane were added to a reaction vessel, heated to 140℃, and stirred at 10 RPM for 2 hours until completely dissolved; the temperature was lowered to 105℃, and 1g of ethyltriphenylphosphine bromide was added under the same stirring conditions; the temperature was then raised to 190℃, and stirred at 30 RPM under vacuum for 3 hours to obtain solid epoxy resin;

[0061] b. By mass parts: 200g of solid epoxy resin, 270g of low viscosity epoxy resin HBEL-153, 100g of rubber modified epoxy resin MX267, 100g of cashew phenol epoxy reactive diluent LITE513DF, 300g of methyl hexahydrophthalic anhydride HNA-100, and 30g of modified imidazole PN-23J are added sequentially into a mixing tank. Under vacuum conditions, the speed is set to 30RPM and stirred for 4 hours to obtain the sealant.

[0062] Comparative Example 4

[0063] a. By mass parts: 710g of epoxy resin HBEL-123 and 290g of bisphenol A propane were added to a reaction vessel, heated to 140℃, and stirred at 10 RPM for 2 hours until completely dissolved; the temperature was lowered to 105℃, and 1g of ethyltriphenylphosphine bromide was added under the same stirring conditions; the temperature was then raised to 195℃, and stirred at 30 RPM under vacuum for 3 hours to obtain solid epoxy resin;

[0064] b. By mass parts: 200g of dodecenyl succinic anhydride CA-I-05 and 800g of methyl hexahydrophthalic anhydride HNA-100 were added to a stirred tank in sequence. Under nitrogen protection, the stirring speed was set to 10 RPM and stirred for 1 hour to obtain an acid-anhydride mixture.

[0065] c. By mass parts: 200g of solid epoxy resin, 250g of low viscosity epoxy resin HBEL-153, 100g of rubber modified epoxy resin MX267, 100g of cashew phenol epoxy reactive diluent LITE513DF, 320g of acid anhydride mixture, and 30g of modified imidazole PN-23J are added sequentially into a mixing tank. Under vacuum conditions, the speed is set to 30RPM and stirred for 3 hours to obtain the sealant.

[0066] The sealants prepared in Examples 1-3 and Comparative Examples 1-4 were tested for the following properties:

[0067] (1) Waterproof performance

[0068] Using an analytical balance, according to GB / T 1034-2008 Test Method for Water Absorption of Plastics, place a 61mm*61mm*1mm sample in water at 25℃ for 24 hours, remove it, wipe it dry, weigh it, and calculate the water absorption rate (unit: ).

[0069] (2) Sealing performance

[0070] Using a leak tester, test the enclosure protection rating according to GB / T 4208-2017, at 5 atmospheres for 1 hour, and observe whether the waterproof indicator label inside the sample changes color.

[0071] (3) Shrinkage performance

[0072] The liquid density of the sealant was tested using a density cup, and the solid density of the sealant block was tested using a density balance. The volumetric shrinkage rate was calculated according to GB / T39818-2021, "Test Method for Shrinkage Rate of Thermosetting Molding Materials," in percentage (%).

[0073] (4) Adhesion strength performance

[0074] Aluminum-aluminum composite materials were bonded together using sealant. The shear strength was tested using a universal testing machine at 25℃ and a shear rate of 10 mm / min, according to GB / T 1742-1979, for adhesive bonding strength. The unit is megapascal (MPa).

[0075] Waterproof performance is characterized by water absorption rate; the lower the value, the better the waterproof performance. Sealing performance is characterized by the color change of the label; no color change indicates good sealing performance. Shrinkage performance is characterized by the volume shrinkage rate after curing; the lower the value, the less shrinkage. Adhesive strength is characterized by shear strength; the higher the value, the better the adhesive strength.

[0076] The test results are shown in Table 1.

[0077] Table 1 Performance test results of each embodiment and comparative example

[0078]

[0079] As can be seen from the data in Table 1, the combined use of solid epoxy resin and cashew phenol epoxy reactive diluent has a significant enhancing effect on waterproof sealing performance, which is better than using either alone; the acid anhydride mixture has a significant enhancing effect on shrinkage and adhesion performance, while glycerol has a enhancing effect on low shrinkage performance; the sealant prepared by this invention has the advantages of being easy to operate as a single component, having good waterproof and sealing performance, low shrinkage, and high bonding strength, and is suitable for waterproof and moisture-proof sealing and bonding of various wearable smart electronic products.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A one-component epoxy sealant, characterized in that, By weight, it includes the following components: 10-20 parts of solid epoxy resin, 20-35 parts of low-viscosity epoxy resin, 10-15 parts of rubber-modified epoxy resin, 10-13 parts of cashew phenol epoxy reactive diluent, 32-35 parts of acid anhydride mixture, and 3-5 parts of modified imidazole. The solid epoxy resin is prepared by the following method: 71-72 parts by mass of epoxy resin and 28-29 parts by mass of bisphenol A propane are added to a reaction vessel, heated to 140-160°C, and stirred at 10 RPM for 1-2 hours until completely dissolved; the temperature is lowered to 95-105°C, and 0.05-0.1 parts by mass of catalyst are added while maintaining the stirring speed at 10 RPM; the temperature is then raised to 185-195°C, a vacuum is drawn, and the stirring speed is set to 30 RPM for 2-3 hours to obtain the solid epoxy resin. The anhydride mixture is prepared by the following method: 18-20 parts by mass of dodecenyl succinic anhydride, 79-80 parts by mass of methyl hexahydrophthalic anhydride, and 1-3 parts by mass of glycerol are sequentially added to a stirred tank, and the mixture is stirred for 0.5-1 hour under nitrogen protection at a speed of 10 RPM to obtain the anhydride mixture.

2. The single-component epoxy sealant according to claim 1, characterized in that, The solid epoxy resin is a solid epoxy resin with a molecular weight of 1345-1395, an epoxy equivalent of 800-835 g / eq, and a softening point of 87-95℃.

3. The single-component epoxy sealant according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin with a molecular weight of 338-346 and an epoxy equivalent of 188-198 g / eq; the bisphenol A propane has a molecular weight of 216-228 and a melting point of 158-159℃; the catalyst is ethyltriphenylphosphine bromide with a molecular weight of 265-371 and a melting point of 204-207℃.

4. The single-component epoxy sealant according to claim 1, characterized in that, The low-viscosity epoxy resin is a bisphenol F type epoxy resin with a viscosity of 800-1500 mPa·s at 25℃ and an epoxy equivalent of 155-165 g / eq; the rubber-modified epoxy resin is a nano-core-shell rubber-modified epoxy resin with a viscosity of 6000-9000 mPa·s at 50℃ and an epoxy equivalent of 260-275 g / eq; the cashew phenol epoxy reactive diluent is a cashew phenol modified epoxy reactive diluent with a viscosity of 90-200 mPa·s at 25℃ and an epoxy equivalent of 250-300 g / eq; the modified imidazole is an imidazole adduct with an average particle size of 2-4 μm and a reaction temperature of 100℃.

5. The single-component epoxy sealant according to claim 1, characterized in that, The dodecenylsuccinic anhydride is an aliphatic anhydride with a molecular weight of 262-270 and an acid value of 395-425 mgKOH / g; the methylhexahydrophthalic anhydride is an anhydride compound with a molecular weight of 164-172 and an acid value of 640-650 mgKOH / g.

6. A method for preparing a one-component epoxy sealant according to any one of claims 1-5, characterized in that, The process includes the following steps: according to the mass fractions, solid epoxy resin, low viscosity epoxy resin, rubber modified epoxy resin, cashew phenol epoxy reactive diluent, acid anhydride mixture, and modified imidazole are sequentially added into a mixing tank, a vacuum is drawn, the speed is set to 30 RPM, and the mixture is stirred for 3 to 4 hours to obtain the single-component epoxy sealant.

7. The application of a single-component epoxy sealant according to any one of claims 1-5 in wearable smart electronic products.

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