Organosilicon modified epoxy adhesive capable of being cured at ultralow temperature and preparation method thereof

Abstract

The invention relates to the technical field of adhesives, in particular to an organic silicon modified epoxy adhesive capable of being cured at an ultralow temperature and a preparation method of the organic silicon modified epoxy adhesive. The problems of high viscosity and poor moisture resistance in a low-temperature environment formed by a common technology are solved. The organic silicon modified epoxy adhesive comprises a component A and a component B, the component A accounts for 20-80% of the total mass, and the component B accounts for 20-80% of the total mass. The prepared adhesive is extremely low in viscosity before curing and suitable for normal-temperature even low-temperature rapid potting, the organic silicon epoxy resin in the sealant prepared by the method is preferentially arranged on the surface, the surface energy is reduced, and the moisture resistance of a cured product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives, in particular to an ultra-low temperature curable organosilicon-modified epoxy adhesive and a preparation method thereof. Background Art

[0002] Epoxy sealant has excellent high temperature resistance and electrical insulation capabilities, is easy to operate, has no small molecule release, has low curing shrinkage, has excellent adhesion to a variety of metal substrates and porous substrates, and is widely used in various packaging fields.

[0003] Most epoxy potting adhesives need to be heated to cure quickly. After curing, the colloid is hard and brittle. After cooling, it causes internal stress, causing deformation, debonding and even damage to the substrate. Therefore, room temperature or even low temperature curing systems have become a development trend. The epoxy curing material has a rigid structure and weak resistance to cold and heat changes. It is easy to crack after being subjected to cold and hot shocks. Therefore, there is a strong demand for epoxy potting adhesives that are resistant to cold and hot shocks and have a certain degree of flexibility.

[0004] After curing, traditional epoxy resins contain a large number of hydroxyl groups, ether bonds, benzene rings and other structures, with high self-absorption rate and poor moisture resistance. Most epoxy resins have high viscosity, which increases significantly with decreasing temperature. How to prepare epoxy potting glue that can be quickly potted and cured at room temperature or even low temperature, is flexible and moisture-proof with high high and low temperature impact resistance has become a difficult problem and development direction in the industry.

[0005] Therefore, it is urgent to propose an ultra-low temperature curable silicone-modified epoxy adhesive and a preparation method to solve the above technical problems. Summary of the invention

[0006] The purpose of the present invention is to solve the problem of high viscosity and poor moisture resistance in low temperature environment formed by common technology. A brief summary of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this summary is not an exhaustive summary of the present invention. It is not intended to identify the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0007] The technical solution of the present invention:

[0008] An ultra-low temperature curable organosilicon-modified epoxy adhesive, the organosilicon-modified epoxy adhesive comprising component A and component B;

[0009] The A component accounts for 20 to 80% of the total mass, and the B component accounts for 20 to 80% of the total mass.

[0010] Preferably, component A is composed of 5-45% of resorcinol diglycidyl ether epoxy resin, 10-50% of glycidyl ester epoxy resin, 10-50% of epoxy diluent, and 5-45% of silicone epoxy resin.

[0011] Preferably, component B is composed of 10-90% of a polythiol curing agent and 0.01-10% of an accelerator.

[0012] Preferably, the glycidyl ester is one of alicyclic glycidyl esters and aromatic glycidyl esters.

[0013] Preferably, the epoxy diluent is one of aliphatic glycidyl ether and alicyclic glycidyl ester.

[0014] Preferably, the silicone epoxy resin is one or more of a linear silicone epoxy resin, a cyclic silicone epoxy resin, and a phenyl silicone epoxy resin.

[0015] Preferably, the polythiol curing agent is one or more of an ester thiol curing agent and an ether thiol curing agent.

[0016] Preferably, the accelerator is one of a tertiary amine accelerator, a fatty amine accelerator, a substituted urea accelerator, and an organic amine accelerator.

[0017] A method for preparing an organosilicon epoxy resin comprises the following steps:

[0018] Step 1: Vinyl cyclohexene oxide and 1,3,5,7-tetramethylcyclotetrasiloxane are used as raw materials, platinum and toluene are added, and nitrogen is introduced to protect the reaction at a temperature of 85°C for 6 hours;

[0019] Step 2: After the reaction is completed, filter, reduce pressure, and distill to obtain an organosilicon epoxy resin.

[0020] A method for preparing an ultra-low temperature curable organosilicon-modified epoxy adhesive, characterized in that it comprises the following steps:

[0021] Step 1: add resorcinol diglycidyl ether epoxy resin and glycidyl ester epoxy resin into a reaction kettle, heat the reaction kettle to 80°C, bake for 1-2h, add epoxy diluent and silicone epoxy resin and stir for 1h, then cool to 30°C after stirring to obtain component A;

[0022] Step 2: Add the polythiol curing agent and the organic amine catalyst into the reaction kettle and stir for 0.5h to obtain component B;

[0023] Step 3: Weigh component A and component B, and stir them under a low-speed mixer for 30 minutes to mix component A and component B evenly to prepare an ultra-low temperature curable silicone-modified epoxy adhesive.

[0024] The present invention has the following beneficial effects:

[0025] The adhesive prepared by the present invention has extremely low viscosity before curing and is suitable for rapid potting at room temperature or even low temperature;

[0026] The adhesive prepared by the present invention does not need to be heated and can be quickly cured at room temperature or even at low temperature;

[0027] The adhesive prepared by the present invention has low curing shrinkage, good flexibility, small internal stress, and good high and low temperature impact resistance;

[0028] The organosilicon epoxy resin in the sealant prepared by the present invention is preferentially arranged on the surface, thereby reducing the surface energy and improving the moisture resistance of the cured product. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the synthesis of silicone epoxy resin. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is described below by the specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0031] Specific implementation method 1: This implementation method is an ultra-low temperature curable silicone modified epoxy adhesive, the silicone modified epoxy adhesive includes component A and component B;

[0032] The A component accounts for 20 to 80% of the total mass, and the B component accounts for 20 to 80% of the total mass.

[0033] The A component preferably accounts for 30-70% of the total mass, and the optimal amount is 40-65%; the B component preferably accounts for 30-70% of the total mass, and the optimal amount is 40-65%.

[0034] The ultra-low temperature curing temperature of the present invention is -50°C to 60°C.

[0035] Specific implementation method 2: In this implementation method, an ultra-low temperature curable silicone-modified epoxy adhesive is provided, wherein component A is composed of 5-45% of resorcinol diglycidyl ether epoxy resin, 10-50% of glycidyl ester epoxy resin, 10-50% of epoxy diluent, and 5-45% of silicone epoxy resin.

[0036] The distribution ratio of group A is 5-30% of resorcinol diglycidyl ether epoxy resin, 10-40% of glycidyl ester epoxy resin, 10-40% of epoxy diluent, and 5-30% of silicone epoxy resin;

[0037] The distribution ratio of group A is 10-25% of resorcinol diglycidyl ether epoxy resin, 15-35% of glycidyl ester epoxy resin, 15-35% of epoxy diluent, and 10-25% of silicone epoxy resin.

[0038] Specific implementation method three: In this implementation method, an ultra-low temperature curable silicone-modified epoxy adhesive is used, wherein component B is composed of 10-90% of a polythiol curing agent and 0.01-10% of an accelerator.

[0039] The distribution ratio of group B is 25-70% of polythiol curing agent and 25-70% of ether polythiol curing agent;

[0040] The proportion of group B is 0.05-5% of organic amine accelerator and 35-60% of ester polythiol curing agent;

[0041] The distribution ratio of group B is 35-65% of ether polythiol curing agent and 0.07-2% of organic amine accelerator.

[0042] Specific implementation method 4: This implementation method is an ultra-low temperature curable silicone-modified epoxy adhesive, and the glycidyl ester is one of alicyclic glycidyl esters and aromatic glycidyl esters, and their common feature is that the viscosity at room temperature is not higher than 1 Pa·s.

[0043] The glycidyl ester is preferably one of diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl epoxidized tetrahydrophthalate, and triglycidyl trimesic acid.

[0044] Specific embodiment 5: This embodiment is a silicone-modified epoxy adhesive that can be cured at ultra-low temperature. The epoxy diluent is one of aliphatic glycidyl ether and alicyclic glycidyl ester. The main feature of this type of epoxy is that the viscosity at room temperature is lower than 0.3 Pa·s, among which a difunctional active diluent with a room temperature viscosity of lower than 0.1 Pa·s is preferred.

[0045] The epoxy diluent is preferably one of 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 4-vinyl-1-cyclohexene diepoxide, and cyclohexane-1,2-dicarboxylic acid diglycidyl ether.

[0046] Specific embodiment six: This embodiment is a silicone-modified epoxy adhesive that can be cured at ultra-low temperature. The silicone epoxy resin is one or more of a linear silicone epoxy resin, a cyclic silicone epoxy resin, and a phenyl silicone epoxy resin. The common characteristics are good compatibility with other epoxy resins and a viscosity at room temperature of less than 0.2 Pa·s.

[0047] The epoxy groups of silicone epoxy resins can be located at the terminal groups or the side groups.

[0048] Specific implementation method seven: In this implementation method, an ultra-low temperature curable silicone-modified epoxy adhesive is used, and the polythiol curing agent is one or more of an ester thiol curing agent and an ether thiol curing agent.

[0049] The polythiol curing agent is a substance containing a thiol group (-SH) with a functionality greater than or equal to 2, and the -SH mass fraction thereof is at least 5wt%, preferably a variety with a -SH content greater than 10wt%, and most preferably a variety with a -SH content greater than 25wt%;

[0050] Polythiol curing agent is a trifunctional, tetrafunctional, hexafunctional and other multifunctional polythiol curing agent. Compared with other curing agents such as amines and anhydrides, it has the characteristics of low-temperature rapid curing. It also contains flexible sulfur chains and a higher refractive index. It has high application value in increasing the toughness and transparency of resins.

[0051] Specific implementation eight: In this implementation, an ultra-low temperature curable organosilicon-modified epoxy adhesive is used, and the accelerator is one of a tertiary amine accelerator, a fatty amine accelerator, a substituted urea accelerator, and an organic amine accelerator.

[0052] The accelerator is preferably one of benzyldimethylamine, triethylamine, triethanolamine, dimethylethanolamine, N,N-dimethylaniline, pyridine, and 2,4,6-tris(dimethylaminomethyl)phenol;

[0053] The accelerator is preferably one of diethylenetriamine, triethylenetetramine, and polyethylenepolyamine;

[0054] The accelerator is preferably one of chlorourea, dimethylimidazole urea, and thiourea;

[0055] The accelerator is preferably one of tetramethylguanidine, acyl-substituted guanidine, alkyl-substituted guanidine and the like.

[0056] Specific embodiment 9: A method for preparing a silicone epoxy resin in this embodiment comprises the following steps:

[0057] Step 1: Vinyl cyclohexene oxide and 1,3,5,7-tetramethylcyclotetrasiloxane are used as raw materials, platinum and toluene are added, and nitrogen is introduced to protect the reaction at a temperature of 85°C for 6 hours;

[0058] Step 2: After the reaction is completed, filter, reduce pressure, and distill to obtain an organosilicon epoxy resin.

[0059] Specific embodiment 10: A method for preparing an ultra-low temperature curable silicone-modified epoxy adhesive in this embodiment comprises the following steps:

[0060] Step 1: add resorcinol diglycidyl ether epoxy resin and glycidyl ester epoxy resin into a reaction kettle, heat the reaction kettle to 80°C, bake for 1-2h, add epoxy diluent and silicone epoxy resin and stir for 1h, then cool to 30°C after stirring to obtain component A;

[0061] Step 2: Add the polythiol curing agent and the organic amine catalyst into the reaction kettle and stir for 0.5h to obtain component B;

[0062] Step 3: Weigh component A and component B, and stir them under a low-speed mixer for 30 minutes to mix component A and component B evenly to prepare an ultra-low temperature curable silicone-modified epoxy adhesive.

[0063] In any of the above embodiments, a proper amount of filler may be added to adjust the strength, hardness, thermal conductivity, and other properties of the cured product, such as silicon dioxide, silicon carbide, zinc oxide, aluminum oxide, aluminum powder, and the like.

[0064] The present invention is further described below in conjunction with embodiments. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0065] Wherein a is resorcinol diglycidyl ether; b is isophthalic acid diglycidyl ester; c is 1,6-hexanediol diglycidyl ether; d is 4-vinyl-1-cyclohexene diepoxide; e is silicone epoxy resin; f is thiol curing agent; g is nano zinc dioxide; and h is 2,4,6-tris(dimethylaminomethyl)phenol.

[0066] The following examples are operated in the same manner, with only the amounts of raw materials modified.

[0067] Dosage a b c d e f g h Example 1 5g 0g 0g 0g 0g 5g 0g 0.01g Example 2 4g 1g 0g 0g 0g 5g 0g 0.01g Example 3 3g 1g 1g 0g 0g 5g 0g 0.01g Example 4 3g 1g 0g 1g 0g 5g 0g 0.01g Example 5 2g 1g 1g 0g 1g 5g 0g 0.01g Example 6 2g 1g 0g 1g 1g 5g 0g 0.001g Example 7 2g 1g 0g 1g 1g 5g 3g 0.001g

[0068] Performance Testing

[0069] Viscosity test: static shear test by rotational rheometer, rotor diameter 50mm flat plate, rotation speed 1s-1, test temperature -25 degrees Celsius.

[0070] Curing time data: the time from curing at -25°C until the sample can fully rebound after being pressed by fingers.

[0071] Tensile strength and elongation at break test: The cured samples were tested according to GB / T5282009 tensile properties of vulcanized rubber and thermoplastic rubber, with a test speed of 100 mm / min and a test temperature of 25°C.

[0072] Hardness test: The cured samples were tested according to GB / T23651-2009 Hardness test for vulcanized rubber and thermoplastic rubber using a Shore A durometer.

[0073] The performance characteristics of the embodiments are shown in the table below.

[0074]

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0076] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An ultra-low temperature curable organosilicon-modified epoxy adhesive, characterized in that: The silicone modified epoxy adhesive includes component A and component B; The A component accounts for 20 to 80% of the total mass, and the B component accounts for 20 to 80% of the total mass.

2. The ultra-low temperature curable organosilicon-modified epoxy adhesive according to claim 1, characterized in that: Component A consists of 5-45% of resorcinol diglycidyl ether epoxy resin, 10-50% of glycidyl ester epoxy resin, 10-50% of epoxy diluent and 5-45% of organic silicon epoxy resin.

3. The ultra-low temperature curable organosilicon-modified epoxy adhesive according to claim 1, characterized in that: Component B is composed of 10-90% of a polythiol curing agent and 0.01-10% of an accelerator.

4. The ultra-low temperature curable organosilicon-modified epoxy adhesive according to claim 2, characterized in that: Glycidyl esters are one of alicyclic glycidyl esters and aromatic glycidyl esters.

5. The ultra-low temperature curable organosilicon-modified epoxy adhesive according to claim 2, characterized in that: Epoxy diluent is a type of aliphatic glycidyl ether or alicyclic glycidyl ester.

6. The ultra-low temperature curable organosilicon-modified epoxy adhesive according to claim 2, characterized in that: The silicone epoxy resin is one or more of a linear silicone epoxy resin, a cyclic silicone epoxy resin, and a phenyl silicone epoxy resin.

7. The ultra-low temperature curable organosilicon-modified epoxy adhesive according to claim 3, characterized in that: The polythiol curing agent is one or more of an ester thiol curing agent and an ether thiol curing agent.

8. The ultra-low temperature curable organosilicon-modified epoxy adhesive according to claim 3, characterized in that: The accelerator is one of a tertiary amine accelerator, a fatty amine accelerator, a substituted urea accelerator, and an organic amine accelerator.

9. A method for preparing an organosilicon epoxy resin, characterized in that: The steps include: Step 1: Vinyl cyclohexene oxide and 1,3,5,7-tetramethylcyclotetrasiloxane are used as raw materials, platinum and toluene are added, and nitrogen is introduced to protect the reaction at a temperature of 85°C for 6 hours; Step 2: After the reaction is completed, filter, reduce pressure, and distill to obtain an organosilicon epoxy resin.

10. A method for preparing an ultra-low temperature curable organosilicon-modified epoxy adhesive, characterized in that: The steps include: Step 1: add resorcinol diglycidyl ether epoxy resin and glycidyl ester epoxy resin into a reaction kettle, heat the reaction kettle to 80°C, bake for 1-2h, add epoxy diluent and silicone epoxy resin and stir for 1h, then cool to 30°C after stirring to obtain component A; Step 2: Add the polythiol curing agent and the organic amine catalyst into the reaction kettle and stir for 0.5h to obtain component B; Step 3: Weigh component A and component B, and stir them under a low-speed mixer for 30 minutes to mix component A and component B evenly to prepare an ultra-low temperature curable silicone-modified epoxy adhesive.

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