CN105862017B - A kind of anti-silver discoloration agent for LED silver bracket and its preparation and film-forming method - Google Patents

Abstract

A kind of anti-silver tarnish agent of LED silver stent and preparation and film build method, it is the silane coupling agent with sulfydryl that anti-silver tarnish agent, which includes a kind of silane coupling agent, it is one or two kinds of can and packaging plastic compatibility the silane coupling agents with vinyl.The LED silver stent for having accomplished fluently gold thread but non-resin-encapsulated is immersed in silane coupling agent mixed solution of the end group containing sulfydryl and vinyl so that silver-based surface can be quickly generated a kind of approximate double-deck polysiloxanes laminated film.The polysiloxanes laminated film is not only formed between silver has good adhesive force, but also compatible with surface encapsulation resin can have good compatibility again.Not only anti-sulphur ability is good, of low cost, not influence later stage encapsulation process, building-up process simple, follow-up easy to use for the anti-silver tarnish agent of the present invention, the advantages that being suitble to large-scale promotion, but also will not generate pollution to environment.

Description

A kind of anti-silver discoloration agent for LED silver bracket and its preparation and film-forming method

technical field

The invention relates to a convenient and fast method for preventing silver or silver-plated materials from vulcanization and discoloration, in particular to a method for preventing sulfur discoloration of LED silver brackets.

Background technique

In recent years, due to the many advantages of light-emitting diode (LED) lamps such as high efficiency, energy saving, long life, wide application range, and environmental protection, the entire LED industry has developed rapidly both at home and abroad. However, with the prolongation of use time, the LED light will gradually become darker, the light decay will increase rapidly, the luminous flux will decrease significantly, the service life of the lamp will become shorter, and in severe cases, the phenomenon of dead light will even occur. This problem is exacerbated by air pollution. The reason is that silver or silver-plated materials are generally used as the bracket base for LED lights at present, which are used for reflection and heat conduction. However, silver material is easy to change color in the air, especially sensitive to sulfur in the atmosphere, and it is easy to generate dark-colored Ag ₂ S, which causes the silver layer to turn black, thus leading to the above-mentioned phenomenon.

Aiming at the problem of discoloration of LED silver substrates, there are currently two commonly used solutions. One is to modify the encapsulation resin covering the silver support to increase its overall crosslinking density. For example, patent CN 102965069 A reports that by optimizing organic The ratio of phenyl, vinyl, and vinyl MQ resins in silicon encapsulants is used to improve the anti-vulcanization effect of encapsulants. Another solution is to directly cover a layer of dense protective film on the LED element, and then encapsulate the silicone resin to improve the anti-sulfur ability of silver. For example, patent CN 104576901 A improves the anti-sulfur ability of LED components by applying a coating of polysilazane material on the surface of LED silver substrates. The former method is easy to operate, but the increase in the density of the silicone will lead to a decrease in the luminous flux of the LED, and the gas barrier properties of the encapsulating molecules are not strong, so the discoloration of the silver substrate cannot be completely eliminated. The latter method can well improve the anti-sulfur performance of the LED element, but its polysilazane synthesis process is complicated and the operation process is cumbersome, which increases the production cost. Therefore, there is an urgent need to develop an anti-silver discoloration agent that not only has good anti-sulfur performance, is environmentally friendly, but also can make the synthesis process and the use process simple, low-cost, and does not affect the subsequent packaging process of LEDs.

Contents of the invention

The object of the present invention is to provide a preparation and film-forming method of an anti-silver discoloration agent for LED silver brackets, which can greatly improve the anti-sulfur performance of LED silver-based.

The present invention is achieved through the following technical solutions.

An anti-silver discoloration agent for LED silver brackets according to the present invention uses two or more silane coupling agents that are compatible with each other as main components; one of the silane coupling agents is a mercapto-containing silane coupling agent , using the mercapto group at the end of this type of coupling agent to form a bond with the silver substrate, so that the combination between the silane coupling agent and the silver base is tighter, the arrangement is more orderly, and the adhesion between it and the silver is increased; by introducing another One or two vinyl-based silane coupling agents compatible with the encapsulant can improve the light transmittance of the encapsulant;

A film-forming method of an anti-silver discoloration agent for LED silver stents. The LED silver stents that have been laid with gold wires but not encapsulated in resin are immersed in a mixed solution of silane coupling agent containing mercapto and vinyl groups at the end groups, and the silver and mercapto groups are used to form a film. The characteristics of the bonding between them make the silane coupling agent with mercapto group enriched on the surface of the silver layer, while the silane coupling agent with vinyl tends to be enriched on the upper layer (with the characteristics of being compatible with organic encapsulation resins), and at the same time Utilizing the property that the silane coupling agent can be dehydrated and polymerized at high temperature, the above silane coupling agent can quickly generate a nearly double-layer polysiloxane composite film on the surface of the silver base. The polysiloxane composite film not only has good adhesion with silver, but also has good compatibility with surface encapsulation resin. Finally, organic resin encapsulation is performed on the polysiloxane composite film formed on the surface of the LED silver base.

An anti-silver discoloration agent for LED silver brackets according to the present invention comprises the following two structural units (1) and (2):

(1) (2)

Wherein, R is -CH ₂ or -C ₂ H ₄ ; when R ₁ =R ₂ =R ₃ , R ₁ , R ₂ and R ₃ can be selected as -OC ₂ H ₅ or -OCH ₃ ; R ₁ =R ₂ , R ₁ and R ₂ can be selected as -OC ₂ H ₅ or -OCH ₃ , and R ₃ can be selected as -CH ₃ .

When R ₄ =R ₅ =R ₆ , R ₄ , R ₅ and R ₆ can be selected as -Cl, -OC ₂ H ₅ , -OCH ₃ , -OC ₂ H ₄ OCH ₃ or -OCOCH ₃ ; R ₄ =R When ₅ = -Cl, R ₆ = -CH ₃ .

An anti-silver discoloration agent for LED silver brackets according to the present invention is prepared from two solutions of A and B at a volume ratio of 15-25:1.

The A solution includes the above structural unit (1), catalyst and solvent.

Preferably, the mass percent of each substance of the A solution is:

The above structural unit (1): 0.1-5.0%;

Catalyst: 1.0-5.0%;

Solvent: 90.0-98.9%.

The B solution includes the above structural unit (2), catalyst and solvent.

Preferably, the mass percent of each substance of the B solution is:

The above structural unit (2): 10.0-20.0%;

Catalyst: 1.0-5.0%;

Solvent: 75.0-89.0%.

The catalyst is an acid catalyst, preferably one or more of formic acid, acetic acid, dilute hydrochloric acid or dilute sulfuric acid.

The solvent may be water, one or more of alcoholic organic solvents such as methanol, ethanol, isopropanol, and n-butanol.

The anti-silver discoloration agent for LED silver stents of the present invention can be formed into a film by various methods such as drip coating, spin coating, and soaking. Preferably, the soaking method is used, and this method can be used on a large scale, which is convenient and simple.

The method for forming a film of an anti-silver discoloration agent for an LED silver bracket according to the present invention comprises the following steps: immerse the LED silver bracket that has been gold-wired but not resin-encapsulated in the above-mentioned anti-silver discoloration agent, takes it out after soaking, and places it in the Dry in an oven at 100-150°C for 10-60 minutes, then take it out.

Compared with the prior art, the present invention has the advantages of:

The anti-silver discoloration agent of the present invention not only has good anti-sulfur ability, low cost, does not affect the subsequent packaging process, simple synthesis process, easy subsequent use and operation, is suitable for large-scale promotion, and has the advantages of not polluting the environment and the like.

The polysiloxane composite film formed by the anti-silver discoloration agent of the present invention not only has good anti-sulfur performance and high permeability, but also introduces mercapto groups at the end to coordinate with silver on the surface of the silver base, so that the formed siloxane film Good adhesion to silver.

The polysiloxane composite film formed by the anti-silver discoloration agent of the present invention has good compatibility with the upper packaging glue.

Description of drawings

Fig. 1 is a principle diagram of forming a polysiloxane composite film on the silver-based surface of an LED according to the present invention, wherein the square dotted line box represents the encapsulation glue.

Fig. 2 is a specific appearance diagram of the anti-sulfur effect of the present invention, in which the five diagrams from top to bottom and from left to right are the appearance diagrams of vulcanization at 0 minute, 15 minutes, 24 hours, 36 hours and 48 hours respectively. Among them, the first blackened in each figure is the LED silver-based bracket represented by embodiment 10, and the rest represent embodiments 7-9 respectively.

Fig. 3 is the specific appearance representation diagram of the permeation of the red ink of the present invention after cooking, wherein the two on the left are the permeation conditions of embodiment 10, and the three on the right are the permeation conditions of embodiments 7-9 from top to bottom, wherein the encapsulating glue and The darker the silver base, the deeper the penetration.

Detailed ways

The invention utilizes two or more silane coupling agents with different functional groups, hydrolyzes itself into silanols and prepares them in a certain proportion, dehydrates and polymerizes at high temperature to form a layer of dense polysiloxane composite film. The dense polysiloxane composite film formed by the invention can not only form good adhesion with the silver base, but also maintain excellent anti-sulfur performance without affecting the encapsulation in the later stage.

According to the present invention, the polysiloxane composite film formed on the silver base of the LED as described above is prepared through the following steps: ① Preparation of anti-silver discoloration solution ② Application method ③ Film forming step.

The present invention will be further described below in conjunction with specific examples, but the present invention is not limited thereby.

The materials used in the present invention can be obtained through public commercial channels unless otherwise specified. At the same time, the LED silver brackets used in the following examples are all commercially available. Before use, the silver-based surface is not further treated with anti-sulfur, and generally there are no restrictions and requirements on the size. The encapsulation glue used in the examples is the general commercial BQ-4138A/B type glue.

1. Preparation of anti-silver discoloration agent components for LED silver brackets.

Example 1.

Preparation of component A of anti-silver discoloration agent for LED silver bracket: Take 40mL ethanol in a 100mL beaker, add dropwise 3.5mL deionized water, 1.6mL acetic acid, shake well, then add 0.7mL 3-mercaptopropyltriethoxysilane, stir (room temperature, medium speed) 18 hours. You can drop a drop of the solution on a glass slide and dry it in an oven at 100°C. If it is a transparent glass body, it can be used. After preparation, store at room temperature at 15°C until use. The solution is A1.

Preparation of component B of anti-silver discoloration agent for LED silver bracket: Take 4mL of ethanol in a 20mL vial, add 3mL of deionized water and 1.2mL of vinyl tris(2-methoxyethoxy)silane dropwise into it, and let it stand for 24 hours. After preparation, store at room temperature (15°C) for later use. The solution is B1.

Example 2.

Preparation of component A of anti-silver discoloration agent for LED silver bracket: Take 40mL of ethanol in a 100mL beaker, add dropwise 5mL of deionized water, 2.5mL of acetic acid, shake well, then add 1.0mL of 3-mercaptopropyltriethoxysilane, stir ( room temperature, medium speed) for 20 hours. You can drop a drop of the solution on a glass slide and dry it in an oven at 150°C. If it is a transparent glass body, it can be used. After preparation, store at room temperature at 25°C until use. The solution is A2.

Preparation of component B of anti-silver discoloration agent for LED silver bracket: Take 4mL of ethanol in a 20mL vial, add dropwise 3mL of deionized water, 1.2mL of vinyl tris(2-methoxyethoxy)silane, and let it stand for 24h. After preparation, store at room temperature at 25°C until use. The solution is B2.

Example 3.

Preparation of component A of anti-silver discoloration agent for LED silver bracket: Take 40mL of methanol in a 100mL beaker, add dropwise 5mL of deionized water, 1.6mL of formic acid, shake well, then add 1.0mL of 3-mercaptopropyltrimethoxysilane, stir (room temperature , medium speed) for 24 hours. It can be taken by taking a drop of the solution and dropping it on a glass slide, and drying it in a 100°C oven. If there is a transparent glass body, it can be used. After preparation, store at room temperature at 20°C until use. The solution is A3.

Preparation of component B of anti-silver discoloration agent for LED silver bracket: Take 4mL of ethanol in a small bottle, add 3mL of deionized water, 0.6mL of acetic acid, and 1.2mL of vinyltriethoxysilane dropwise into the vial, and let it stand for 24 hours. After preparation, store at room temperature at 20°C until use. The solution is B3.

2. Preparation of anti-silver discoloration agent for LED silver bracket.

Example 4.

Take 4mL of the above A1 solution, add 0.35mL of B1 solution, and stir for 0.5 hours. After preparation, store at room temperature (15°C) until use. The anti-silver discoloration agent is C1.

Example 5.

Take 4mL of the above A2 solution, add 0.50mL of B2 solution, and stir for 2 hours. After preparation, store at room temperature at 25°C until use. The anti-silver discoloration agent is C2.

Example 6.

Take 4mL of the above A3 solution, add 0.2mL of B2 solution, and stir for 1 hour. After preparation, store at room temperature at 20°C until use. The anti-silver discoloration agent is C2.

3. Film-forming preparation process.

Example 7.

Using the anti-silver discoloration agent C1 prepared in Example 4, soak the LED silver bracket into it by soaking method, take it out after 5-10 minutes, and then directly put it in an oven at 100-150°C for drying, and take it out after 10-60 minutes , try to keep the groove solution from spilling during this process.

Example 8.

Using the anti-silver discoloration agent C2 prepared in Example 5, soak the LED silver bracket into it by soaking method, take it out after 5-10 minutes, and then directly put it in an oven at 100-150°C for drying, and take it out after 10-60 minutes , try to keep the groove solution from spilling during this process.

Example 9.

Use the anti-silver discoloration agent C3 prepared in Example 6, soak the LED silver bracket into it by soaking method, take it out after 5-10 minutes, and then directly put it in an oven at 100-150°C for drying, and take it out after 10-60 minutes , try to keep the groove solution from spilling during this process.

Divide the anti-sulfur treated LED silver brackets of Examples 7-9 into two parts, one part is encapsulated with polysiloxane resin, and the encapsulation and curing steps are: 80°C/1 hour+150°C/3 hours. The other part is not encapsulated.

Comparative Example 10.

The LED silver bracket does not undergo anti-vulcanization treatment, and part of it is directly encapsulated with polysiloxane encapsulation glue. The encapsulation and curing steps are: 80 ° C / 1 hour + 150 ° C / 3 hours. The other part is not encapsulated.

Example 11: Comparison of anti-vulcanization effects.

The anti-vulcanization effect of the LED silver bracket (without encapsulation glue) in Examples 7-10 was tested, and the detection method was: sulfur bloom accelerated vulcanization experiment.

The specific test steps are as follows: Put the LED silver brackets (without encapsulant) in Examples 7-10 into a 500mL sealed glass bottle, which contains 20g of sulfur and 0.2g of deionized water, and under the sealed condition of 100°C, After 15 minutes, 24 hours, 36 hours, and 48 hours after vulcanization, take out the sulfur bottle at a fixed point, wait until it reaches room temperature, take out the LED silver bracket to compare the degree of vulcanization, and the specific vulcanization conditions are shown in the table below:

Silver-based sulfide condition/sample Example 7 Example 8 Example 9 Example 10 Sulfurization for 15 minutes Silver-based surface condition keep it bright keep it bright keep it bright completely black Sulfurized 24-hour silver-based surface condition keep it bright keep it bright keep it bright Silver-based surface condition after 36 hours of vulcanization keep it bright keep it bright keep it bright Condition of silver-based surface after vulcanization for 48 hours corner blackened part corner blackened part corner blackened part

The specific appearance after vulcanization can be seen in Figure 2.

Embodiment 12: Determination of light decay after comparative vulcanization.

The anti-vulcanization effect of the LED silver bracket (with encapsulation glue) in Examples 7-10 was tested. The detection method was: after the sulfur bloom accelerated vulcanization test, the light attenuation test was carried out.

The specific test steps are as follows: Put the LED silver brackets (with sealing glue) in Examples 7-10 into a 500mL sealed glass bottle, which contains 20g of sulfur and 0.2g of deionized water. Take out the sulfur flower bottle every 2 hours, and when it is about to reach room temperature, take out the LED silver bracket to measure the light decay. Please refer to the following table for the specific step-by-step light attenuation data:

Light decay/sample Example 7 Example 8 Example 9 Example 10 Light decay after 2h vulcanization 4.6% 4.4% 4.8% 53.0% (dead lights) Gradual light decay after 4h vulcanization 1.7% 1.9% 1.7% Gradual light decay after 6h vulcanization 1.5% 1.3% 1.6% Light decay after 8h vulcanization step by step 1.1% 1.5% 1.5%

Example 13: High-temperature red ink test, comparing the anti-permeation performance of the encapsulation adhesive after curing.

Put the LED silver brackets (with encapsulation glue) in Examples 7-10 into a 500mL stainless steel cup filled with red ink, cook at high temperature, and test whether the surface encapsulation will be affected by sealing a protective film on the surface of the silver base The permeability of the glue.

The specific test conditions are as follows: 170°C red ink solution (red ink: ethanol = 1:1) was cooked for 1 hour. See the table below for specific anti-penetration conditions:

Permeability/sample Example 7 Example 8 Example 9 Example 10 Penetration of red ink medium penetration medium penetration medium penetration heavily penetrated

See accompanying drawing 3 for the specific permeated appearance of the red ink after cooking.

Claims (7)

1. an anti-silver discoloration agent for LED silver support is characterized in that it comprises the following two structural units: (1) (2) In formula (1), R is -CH ₂ or -C ₂ H ₄ ; when R ₁ =R ₂ =R ₃ , R ₁ , R ₂ and R ₃ are -OC ₂ H ₅ ; when R ₁ =R ₂ , R ₁ and R ₂ are -OC ₂ H ₅ or -OCH ₃ , R ₃ is -CH ₃ ; In formula (2), when R ₄ =R ₅ =R ₆ , R ₄ , R ₅ and R ₆ are -Cl, -OC ₂ H ₅ , -OCH ₃ , -OC ₂ H ₄ OCH ₃ or -OCOCH ₃ ; When R ₄ =R ₅ =-Cl, R ₆ =-CH ₃ . 2. the preparation method of the anti-silver discoloration agent of LED silver bracket claimed in claim 1 is characterized in that it is formulated by the ratio of A and B two kinds of solutions by volume ratio 15-25:1; Described A solution comprises above-mentioned structural unit (1), catalyst and solvent, and the mass percentage of its each substance is: The above structural unit (1): 0.1-5.0%; Acid catalyst: 1.0-5.0%; Solvent: 90.0-98.9%; Described B solution comprises above-mentioned structural unit (2), catalyst and solvent, and the mass percentage of its each substance is: The above structural unit (2): 10.0-20.0%; Acid catalyst: 1.0-5.0%; Solvent: 75.0-89.0%. 3. The preparation method of the anti-silver discoloration agent for LED silver brackets according to claim 2, characterized in that the catalyst is one or more of formic acid, acetic acid, dilute hydrochloric acid or dilute sulfuric acid. 4. the preparation method of LED silver bracket anti-silver discoloration agent according to claim 2 is characterized in that described solvent is water or alcoholic organic solvent. 5. the preparation method of LED silver bracket anti-silver discoloration agent according to claim 4 is characterized in that described alcoholic organic solvent is one or more in methanol, ethanol, Virahol, n-butanol . 6. The film-forming method of the anti-silver discoloration agent for LED silver stents according to claim 1, characterized in that the anti-silver discoloration agent for LED silver stents is film-formed by drip coating, spin coating or soaking. 7. The film-forming method according to claim 6, characterized in that the soaking method is to immerse the LED silver bracket that has been gold-wired but not resin-encapsulated in the anti-silver discoloration agent, take it out after soaking, and place it in 100 Dry in an oven at -150°C for 10-60 minutes.