CN107189447A - LED packaging silicon rubbers of wet-heat resisting and its preparation method and application - Google Patents

Abstract

The invention relates to heat-and-humidity-resistant LED packaging silica gel, a preparation method and application thereof, and belongs to the technical field of material chemistry. The heat-and-humidity-resistant LED encapsulation silicone is composed of component A and component B, wherein part A includes: methyl phenyl vinyl silicone resin, platinum catalyst, and addition type tackifier; part B includes: methyl phenyl vinyl Base silicone resin, methyl phenyl hydrogen silicone resin, reaction inhibitor. The heat and humidity resistant LED packaging silica gel, through the selection of specific raw materials to cooperate with each other, has obtained the heat and humidity resistant LED packaging silica gel, which improves the heat and humidity resistance of SMD devices and solves the problem of moisture absorption in the storage process of SMD devices and the lead-free reflow soldering process. The problem of easy cracking and degumming in the medium and long term reduces the risk and improves the production efficiency.

Description

Moisture and heat resistant LED encapsulation silica gel and its preparation method and application

technical field

The invention relates to the technical field of material chemistry, in particular to a heat-and-humidity-resistant LED packaging silica gel and a preparation method and application thereof.

Background technique

At present, a large part of the current commercialized LED lighting devices are packaged in SMD (Surface Mount Type), and high-fold LED silicone resin has excellent transparency, heat resistance and UV aging resistance, so it has become a popular choice for SMD devices. The main packaging material.

However, in the actual application process, after the SMD device is packaged with high-fold silicone resin, due to the sealing property or the hygroscopicity and gas permeability of the packaging material, it will inevitably absorb water vapor during the storage process, and the SMD device needs to be mounted. On the PCB circuit board, in the lead-free reflow soldering process, the moisture-absorbing SMD devices are prone to colloidal cracking and detachment, which will damage the packaging structure.

Contents of the invention

Based on this, it is necessary to address the above problems and provide a heat-and-humidity-resistant LED packaging silica gel, which improves the heat-and-moisture resistance of SMD devices and solves the problem of moisture absorption in the storage process of SMD devices. The problem of easy cracking and degumming during the reflow soldering process reduces the risk and improves production efficiency.

A kind of heat and humidity resistant LED encapsulation silicone, composed of A component and B component,

The A component is prepared from the following raw materials in weight percentage:

Methylphenyl vinyl silicone resin 40%-60%

Platinum catalyst 0.0002%-0.002%

Additive tackifier 0.1%-5%

The B component is mainly prepared from the following raw materials in weight percentage:

Methylphenyl vinyl silicone resin 10%-40%

Methylphenyl hydrogen silicone resin 10%-45%

Reaction inhibitor 0.01%-0.2%

The sum of the A component and B component raw materials is 100%.

For the above heat and humidity resistant LED packaging silica gel, select a methylphenyl vinyl silicone resin with a specific structure, which can ensure the strength and flexibility of the cured product of the MDT type phenyl vinyl silicone resin and reduce the hygroscopicity of the cured product; and, choose silicon The main function of boron-type tackifier is to improve the cohesive force between the colloid and the substrate. The above-mentioned silicon-boron-type tackifier greatly improves the bonding force with PPA and silver-plated metal during the curing process, especially After a period of high-temperature baking, such as a standard baking condition of 170°C/3hrs, the addition of silicon-boron tackifier improves the sealing between the colloid and the substrate, and reduces the water vapor from the interface between the colloid and the substrate. Possibility of entering SMD devices; and with MDT type methyl phenyl hydrogen silicone resin, it can ensure the cross-linking density of the cured product, improve the toughness and reduce the hygroscopicity of the cured product.

In one of the embodiments, the A component is prepared from the following raw materials in weight percent:

Methylphenyl vinyl silicone resin 45%-55%

Platinum catalyst 0.0004%-0.001%

Additive tackifier 1%-3%

The B component is mainly prepared from the following raw materials in weight percentage:

Methylphenyl vinyl silicone resin 15%-35%

Methylphenyl hydrogen silicone resin 25%-45%

Reaction inhibitor 0.05%-0.1%.

The addition amount of the above-mentioned toluene phenyl vinyl silicone resin in the formula is preferably 45%-55%, the addition amount of the methyl phenyl vinyl silicone resin is determined according to the ratio of SiH/Vi, and the SiH/vi value is between 1-2.0 Meanwhile, when the content of the methylphenyl hydrogen-containing silicone resin is too low, a desired hardness cannot be obtained, and when the content of the methylphenyl hydrogen-containing silicone resin is too high, the curing of the glue may be affected.

When the amount of platinum catalyst added is too small, the curing time will be prolonged and the degree of curing will be incomplete. better effect.

The addition amount of the addition-type tackifier is preferably 1%-2%. When the amount is too small, the proper bonding effect cannot be achieved. When the amount is too much, the transparency of the colloid and the curing of the glue will be affected.

After mixing, in order to make the glue have a longer service life and viscosity stability, a reaction inhibitor is selected to be added, and the added amount ranges from 0.01% to 0.2%. When the added amount is too small, a good inhibitory effect cannot be achieved. If it is too much, the curing time of the colloid will be prolonged, the degree of curing will be reduced, and the desired hardness cannot be obtained. The added amount is preferably 0.05% to 0.1%.

In one of the embodiments, the methylphenyl vinyl silicone resin has the following chemical formula:

(PhSiO _3/2 )a(Ph ₂ SiO _2/2 )b(Me ₂ SiO _2/2 )c(ViMe ₂ SiO _1/2 )d

Wherein, a+b+c+d=1, and 0<a<0.6, 0<b<0.4, 0<C<0.4, 0<d<0.3;

The methylphenyl hydrogen-containing silicone resin has the following chemical formula:

(PhSiO _3/2 )a(Ph ₂ SiO _2/2 )b(HMe ₂ SiO _1/2 )c

Among them, a+b+c=1 0<a<0.5, 0<b<0.4, 0<C<0.4;

The addition type tackifier is selected from silicon boron type addition type tackifier, has the following structure:

CH ₂ OCHCH ₃ H ₆ (CH ₃ O) ₂ Si0(Ph ₂ SiO ₂ /2)a(MeSiO ₂ /2)b(BO ₃ /2)cOSi(OCH ₃ ) ₂ CH ₂ OCHCH ₃ H ₆ , where 0 <a<0.7, 0<b<0.3, 0<c<0.1

When the boron content in the silicon-boron type tackifier is too high, it may cause the problem of deliquescence in the air. Therefore, the molar percentage of the (BO ₃ /2)c unit is controlled at 0<c<0.1,

Ph is phenyl, Me is methyl, Vi is vinyl, Si is silicon, O is oxygen, H is hydrogen, and a, b, c, d represent the average mole percentage of structural units in macromolecules.

In one of the embodiments, the molar ratio of SiH/Vi in the LED packaging silica gel is 1-2. Preferably 1.2-1.5. When SiH/vi is in this range, the curing reaction is the most complete (residual reactive groups in the cured product are the smallest), showing optimal performance, and the hygroscopicity of the cured product is reduced, and the moisture barrier performance is improved.

In one embodiment, in the methylphenyl hydrogen-containing silicone resin, 0.2<a<0.45, 0.1<b<0.25, 0.1<C<0.35, and the (HMe ₂ SiO _1/2 ) group is an encapsulating end group. The methylphenyl hydrogen-containing silicone resin has an MDT structure, and the molecular chain is branched. In the structure, the "T" (PhSiO _3/2 ) chain links play a reinforcing role, and the "D" (Ph ₂ SiO _{2/ 2)} The chain link provides a "flexible" segment to improve flexibility, and the side end of the D chain link is a phenyl group, which improves the steric hindrance effect and effectively improves the moisture barrier property. The molar percentage of the "T" link Between 0-50%, preferably 20%-45%, the molar percentage of "D" chain link is between 0%-40%, preferably 10%-25%, the M chain link is a hydrogen-containing functional group, its The molar percentage is 0-40%, preferably 10%-35%, especially the M chain section is a capping group, and each molecular chain contains at least 2 M units.

In one of the embodiments, the refractive index of the methylphenyl vinyl silicone resin is not less than 1.54, the viscosity at 25°C is 5000cps-100000cps; (preferably 30000-60000cps), the molecular weight is 200-1500, and the polydispersity The index (PDI) is less than 1.3, and the mole percentage of molecules with molecular weight less than 500 is less than 1%;

The refractive index of the methylphenyl hydrogen-containing silicone resin is not less than 1.54, the viscosity at 25°C is 200cps-5000cps, (preferably 1000-2000cps), the molecular weight is 500-1000, and the mass fraction of H is 0.1%-0.6 % (preferably 0.2%-0.5%). When the hydrogen content is too small, the crosslinking density will decrease and the hygroscopicity will increase. When the hydrogen content is too high, the crosslinking density will increase, but at the same time the brittleness will increase and the flexibility will decrease. Controlling the H content in the above range will have a better effect .

In one embodiment, the platinum catalyst is selected from: 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum(0), 1,3-divinyl- At least one of 1,1,3,3-tetramethyldisiloxane platinum(0), hexachloroplatinum hydride;

Preferred is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum(0) toluene solution, 1,3-divinyl-1,1,3,3-tetramethyl Platinum disiloxane platinum (0) isopropanol solution, at least one of hexachloroplatinum hydrogen acid isopropanol solution;

The reaction inhibitor is selected from at least one of ethynyl cyclohexanol, polyvinyl compounds, and silane-modified acetylenic alcohols.

In one embodiment, the platinum catalyst is 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum(0).

This Faming also discloses the preparation method of the above-mentioned heat-and-humidity resistant LED encapsulation silica gel, comprising the following steps:

Preparation of component A: Mix the raw materials of component A evenly to obtain;

Preparation of component B: Mix all the ingredients of component B evenly to get ready.

The above method for preparing the heat-and-humidity-resistant LED encapsulating silica gel has the characteristics of simple process and high reliability, and can be conveniently applied in industrial production.

In one of the embodiments, in the step of preparing component A, each raw material is added to the mixer respectively, stirred evenly at room temperature, vacuumized to remove foaming, and then obtained; preferably, each raw material is respectively added to the planetary mixer, and the rotation The speed is 35-45r/min, stir at room temperature for 0.8-1.2h, stop stirring, and vacuumize for defoaming.

In the step of preparing component B, add each raw material into a blender, stir evenly at room temperature, and vacuumize to remove foaming. Preferably, each raw material is added to a planetary mixer respectively, the rotation rate is 35-45r/min, stirred at room temperature for 0.8-1.2h, the stirring is stopped, and the vacuum is used for defoaming.

The above normal temperature refers to 15-35°C, preferably 25°C.

The present invention also discloses the application of the above-mentioned heat-and-humidity-resistant LED encapsulating silica gel in encapsulating LEDs.

Compared with the prior art, the present invention has the following beneficial effects:

The heat-and-humidity-resistant LED packaging silica gel of the present invention improves the heat-and-humidity resistance of SMD devices by selecting specific raw materials to cooperate with each other, and solves the problems of moisture absorption in the storage process of SMD devices and easy cracking and degumming in the lead-free reflow soldering process. problems, thereby reducing risks and improving production efficiency.

The preparation method of the heat-and-humidity-resistant LED packaging silica gel of the present invention has the characteristics of simple process and high reliability, and can be conveniently applied in industrial production.

The heat-and-moisture-resistant LED encapsulating silica gel can be used in encapsulating LEDs, especially the use of the LED encapsulating glue to encapsulate SMD devices can greatly improve the heat-and-moisture resistance performance of the SMD devices.

Description of drawings

Fig. 1 is a schematic diagram of the relationship between LED chip and packaging glue coating in the background technology;

Among them: 1. Packaging glue; 2. Phosphor powder; 3. Gold wire; 4. Bracket; 5. Chip.

detailed description

In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the associated drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The raw materials used in the following examples are all commercially available.

Example 1

A kind of heat and humidity resistant LED encapsulation silicone, composed of A component and B component,

The A component is prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.48(Ph ₂ SiO _2/2 )0.16(Me ₂ SiO _2/2 )0.09(ViMe ₂ SiO _1/2 )0.27, viscosity 30000cps, refractive index 1.543, molecular weight MW=951, PDI=1.253) 50g

Platinum catalyst (content is 5000ppm Pt-1,3,5,7 tetramethyl-divinylsilane toluene solution) 0.2g

Addition type tackifier (boron type tackifier,

CH ₂ OCHCH ₃ H ₆ (CH ₃ O) ₂ Si0(Ph ₂ SiO ₂ /2)0.68(MeSiO ₂ /2)0.25(BO ₃ /2)0.07OSi(OCH ₃ ) ₂ CH ₂ OCHCH ₃ H ₆ )

1.0g

The B component is mainly prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.48(Ph ₂ SiO _2/2 )0.16(Me ₂ SiO _2/2 )0.09(ViMe ₂ SiO _1/2 )0.27, viscosity 30000cps, refractive index 1.543, molecular weight MW=951, PDI=1.253) 20g

Methylphenyl hydrogen-containing silicone resin ((PhSiO _3/2 )0.51(Ph ₂ SiO _2/2 )0.25(HMe ₂ SiO _1/2 )0.24, viscosity 1000cps, refractive index 1.54, molecular weight mw=975, hydrogen content 0.3%) 30g

Reaction inhibitor (1-ethynyl cyclohexanol) 0.03g

The heat-and-humidity-resistant LED encapsulation silica gel of this embodiment is prepared by the following method:

1. Preparation of component A.

Add each raw material in component A into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component A.

2. Preparation of component B.

Add each raw material in component B into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component B.

Example 2

A kind of heat and humidity resistant LED encapsulation silicone, composed of A component and B component,

The A component is prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.5(Ph ₂ SiO _2/2 )0.16(Me ₂ SiO _2/2 )0.07(ViMe ₂ SiO _1/2 )0.27, viscosity 40000cps, refractive index 1.545, molecular weight MW=1025, PDI=1.237) 50g

Platinum catalyst (content is 5000ppm Pt-1,3,5,7 tetramethyl-divinylsilane toluene solution) 0.2g

Addition type tackifier (boron type tackifier,

CH ₂ OCHCH ₃ H ₆ (CH ₃ O) ₂ Si0(Ph ₂ SiO ₂ /2)0.68(MeSiO ₂ /2)0.25(BO ₃ /2)0.07OSi(OCH ₃ ) ₂ CH ₂ OCHCH ₃ H ₆ )

1.0g

The B component is mainly prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.5(Ph ₂ SiO _2/2 )0.16(Me ₂ SiO _2/2 )0.07(ViMe ₂ SiO _1/2 )0.27, viscosity 40000cps, refractive index 1.545, molecular weight MW=1025, PDI=1.237) 15g

Methylphenyl hydrogen-containing silicone resin ((PhSiO _3/2 ) 0.48 (Ph ₂ SiO _2/2 ) 0.27 (HMe ₂ SiO _1/2 ) 0.25, viscosity 2000cps, refractive index 1.54, molecular weight mw=700, hydrogen content 0.25%) 35g

Reaction inhibitor (1-ethynyl cyclohexanol) 0.03g

The heat-and-humidity-resistant LED encapsulation silica gel of this embodiment is prepared by the following method:

1. Preparation of component A.

Add each raw material in component A into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component A.

2. Preparation of component B.

Add each raw material in component B into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component B.

Example 3

A kind of heat and humidity resistant LED encapsulation silicone, composed of A component and B component,

The A component is prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.51(Ph ₂ SiO _2/2 )0.15(Me ₂ SiO _2/2 )0.07(ViMe ₂ SiO _1/2 )0.27, viscosity 45000cps, refractive index 1.543, molecular weight MW=1105, PDI=1.221) 50g

Platinum catalyst (5000ppm Pt-1,3,5,7 tetramethyl-divinylsilane toluene solution)

0.2g

Addition type tackifier (boron type tackifier,

CH ₂ OCHCH ₃ H ₆ (CH ₃ O) ₂ Si0(Ph ₂ SiO ₂ /2)0.68(MeSiO ₂ /2)0.25(BO ₃ /2)0.07OSi(OCH ₃ ) ₂ CH ₂ OCHCH ₃ H ₆ ) 1.0 g

The B component is mainly prepared from the following raw materials:

Methylphenyl vinyl silicone resin (((PhSiO _3/2 )0.51(Ph ₂ SiO _2/2 )0.15(Me ₂ SiO _2/2 )0.07(ViMe ₂ SiO _1/2 )0.27, viscosity is 45000cps, refractive Rate is 1.543, molecular weight MW=1105, PDI=1.221) 12g

Methylphenyl hydrogen-containing silicone resin ((PhSiO _3/2 ) 0.48 (Ph ₂ SiO _2/2 ) 0.27 (HMe ₂ SiO _1/2 ) 0.25 has a viscosity of 2000cps, a refractive index of 1.54, a molecular weight of mw=700, and a hydrogen content of 0.25 %) 38g

Reaction inhibitor (1-ethynyl cyclohexanol) 0.03g

The heat-and-humidity-resistant LED encapsulation silica gel of this embodiment is prepared by the following method:

1. Preparation of component A.

Add each raw material in component A into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component A.

2. Preparation of component B.

Add each raw material in component B into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component B.

Example 4

A kind of heat and humidity resistant LED encapsulation silicone, composed of A component and B component,

The A component is prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.52(Ph ₂ SiO _2/2 )0.15(Me ₂ SiO _2/2 )0.08(ViMe ₂ SiO _1/2 )0.25, viscosity is 50000cps, refractive index 1.543, molecular weight MW=1208, PDI=1.228) 50g

Platinum catalyst (content is 5000ppm Pt-1,3,5,7 tetramethyl-divinylsilane toluene solution) 0.2g

Addition type tackifier (boron type tackifier,

CH ₂ OCHCH ₃ H ₆ (CH ₃ O) ₂ Si0(Ph ₂ SiO ₂ /2)0.68(MeSiO ₂ /2)0.25(BO ₃ /2)0.07OSi(OCH ₃ ) ₂ CH ₂ OCHCH ₃ H ₆ )

1.0g

The B component is mainly prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.52(Ph ₂ SiO _2/2 )0.15(Me ₂ SiO _2/2 )0.08(ViMe ₂ SiO _1/2 )0.25, viscosity 50000cps, refractive index 1.543, molecular weight MW=1208, PDI=1.228) 8g

Methylphenyl hydrogen-containing silicone resin ((PhSiO _3/2 )0.51(Ph ₂ SiO _2/2 )0.25(HMe ₂ SiO _1/2 )0.24, viscosity 2000cps, refractive index 1.54, molecular weight mw=700, hydrogen content 0.2%) 42g

Reaction inhibitor (1-ethynyl cyclohexanol) 0.03g

The heat-and-humidity-resistant LED encapsulation silica gel of this embodiment is prepared by the following method:

1. Preparation of component A.

Add each raw material in component A into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component A.

2. Preparation of component B.

Add each raw material in component B into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component B.

Example 5

A kind of heat and humidity resistant LED encapsulation silicone, composed of A component and B component,

The A component is prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.53(Ph ₂ SiO _2/2 )0.17(Me ₂ SiO _2/2 )0.04(ViMe ₂ SiO _1/2 )0.26, viscosity 50000cps, refractive index 1.543, molecular weight MW=1208, PDI=1.228) 50g

Platinum catalyst (content is 5000ppm Pt-1,3,5,7 tetramethyl-divinylsilane toluene solution) 0.2g

Addition type tackifier (boron type tackifier,

CH ₂ OCHCH ₃ H ₆ (CH ₃ O) ₂ Si0(Ph ₂ SiO ₂ /2)0.68(MeSiO ₂ /2)0.25(BO ₃ /2)0.07OSi(OCH ₃ ) ₂ CH ₂ OCHCH ₃ H ₆ )

1.0g

The B component is mainly prepared from the following raw materials:

Methylphenyl vinyl silicone resin ((PhSiO _3/2 )0.52(Ph ₂ SiO _2/2 )0.17(Me ₂ SiO _2/2 )0.04(ViMe ₂ SiO _1/2 )0.26, viscosity 50000cps, refractive index 1.543, molecular weight MW=1208, PDI=1.228) 5g

Methylphenyl hydrogen-containing silicone resin ((PhSiO _3/2 )0.51(Ph ₂ SiO _2/2 )0.25(HMe ₂ SiO _1/2 )0.24, viscosity 1500cps, refractive index 1.54, molecular weight mw=600, hydrogen content 0.25%) 45g

Reaction inhibitor (1-ethynyl cyclohexanol) 0.03g

The heat-and-humidity-resistant LED encapsulation silica gel of this embodiment is prepared by the following method:

1. Preparation of component A.

Add each raw material in component A into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component A.

2. Preparation of component B.

Add each raw material in component B into a planetary mixer, mix and stir at room temperature for 1.0 h, vacuumize and defoam to obtain component B.

Comparative example 1

A heat-and-humidity-resistant LED packaging silica gel, which is basically similar to the silica gel in Example 1, the difference is:

Component A in Comparative Example 1 was added with 6g of methylphenylvinyl silicone oil.

Comparative example 2

A heat-and-humidity-resistant LED packaging silica gel, which is basically similar to the silica gel in Example 2, the difference is:

The silicon-boron type tackifier in this comparative example 2 was replaced by Shin-Etsu Chemical KBM-403 tackifier, and the tackifier was composed of r-glycidoxytrimethylsilane.

Comparative example 3

A heat-and-humidity-resistant LED packaging silica gel, which is basically similar to the silica gel in Example 3, the difference is:

Component B in Comparative Example 3 is added with 5g of hydrogen-containing silicone oil, the composition of which is tetramethyldiphenyltrisiloxane, and its structure is as follows:

Comparative example 4

A heat-and-humidity-resistant LED packaging silica gel, which is basically similar to the silica gel of Example 4, the difference is:

The A component in this comparative example 4 is added with the vinyl silicone oil of 6g, and the structural formula of this vinyl silicone oil is as follows:

Comparative example 5

A heat-and-humidity-resistant LED encapsulating silica gel, which is basically similar to the silica gel in Example 5, the difference is that:

Component B in Comparative Example 5 is added with 6g of methylphenyl vinyl silicone oil and 6g of methylphenyl hydrogen-containing silicone oil. The composition of the methylphenyl vinyl silicone oil is as follows:

The composition of this methyl phenyl hydrogen silicone oil is as follows:

Experimental example

The heat-and-humidity-resistant LED encapsulants prepared from different examples and comparative examples were tested for performance.

The test method is as follows:

1. Mix agent A and agent B evenly in a certain proportion, and dispense glue on the SMD5050 patch;

2. Baking and curing at 80℃/1hrs+170℃/3hrs;

3. Put the cured SMD5050 patch into the constant temperature and humidity machine, the humidity RH=85%, the temperature Ta=85%; place them for 24h, 48h, 72h respectively;

4. Take out the patch and recover for 20 minutes in a standard laboratory,

5. Carry out lead-free reflow soldering process, 260℃/30s, 3 times, record the number of cracked and degummed glue; cracked or degummed glue is recorded as failure.

The test results are shown in the table below.

Table 1. Formulas and performance test results of various LED encapsulation adhesives

As can be seen from the above results, when the amount of hydrogen-containing silicone resin in the formula increases (Vi/SiH value increases from small to large), the hardness of the colloid after curing increases, showing that the failure percentage of the MSL test decreases (the best result is the embodiment). 4vi/SiH=1/1.5), but when phenylvinyl silicone oil is added to the formula, the hardness of the cured colloid decreases, which is manifested as an increase in the failure percentage of the MSL test.

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

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. A heat-and-humidity-resistant LED encapsulation silica gel, characterized in that it consists of component A and component B, The A component is prepared from the following raw materials in weight percentage: Methylphenyl vinyl silicone resin 40%-60% Platinum catalyst 0.0002%-0.002% Additive tackifier 0.1%-5% The B component is mainly prepared from the following raw materials in weight percentage: Methylphenyl vinyl silicone resin 10%-40% Methylphenyl hydrogen silicone resin 10%-45% Reaction inhibitor 0.01%-0.2% The sum of the A component and B component raw materials is 100%. 2. The heat-and-humidity-resistant LED packaging silica gel according to claim 1, characterized in that, the A component is prepared from the following raw materials in weight percentage: Methylphenyl vinyl silicone resin 45%-55% Platinum catalyst 0.0004%-0.001% Additive tackifier 1%-3% The B component is mainly prepared from the following raw materials in weight percentage: Methylphenyl vinyl silicone resin 15%-35% Methylphenyl hydrogen silicone resin 25%-45% Reaction inhibitor 0.05%-0.1%. 3. The heat-and-humidity-resistant LED packaging silica gel according to claim 1 or 2, wherein the methylphenyl vinyl silicone resin has the following chemical formula: (PhSiO _3/2 )a(Ph ₂ SiO _2/2 )b(Me ₂ SiO _2/2 )c(ViMe ₂ SiO _1/2 )d Wherein, a+b+c+d=1, and 0<a<0.6, 0<b<0.4, 0<C<0.4, 0<d<0.3; The methylphenyl hydrogen-containing silicone resin has the following chemical formula: (PhSiO _3/2 )a(Ph ₂ SiO _2/2 )b(HMe ₂ SiO _1/2 )c Among them, a+b+c=1 0<a<0.5, 0<b<0.4, 0<C<0.4; The addition type tackifier is selected from silicon boron type addition type tackifier, has the following structure: CH ₂ OCHCH ₃ H ₆ (CH ₃ O) ₂ Si0(Ph ₂ SiO ₂ /2)a(MeSiO ₂ /2)b(BO ₃ /2)cOSi(OCH ₃ ) ₂ CH ₂ OCHCH ₃ H ₆ ; where, Ph is a phenyl group, Me is a methyl group, B is a boron atom, a, b, and c represent the average mole percentage of each structural unit in the molecule, among which 0<a<0.7, 0<b<0.3, 0<c< 0.1 Ph is phenyl, Me is methyl, Vi is vinyl, Si is silicon, O is oxygen, H is hydrogen, and a, b, c, d represent the average mole percentage of structural units in macromolecules. 4. The heat-and-humidity resistant LED packaging silica gel according to claim 3, characterized in that, in the LED packaging silica gel, the molar ratio of SiH/Vi is 1-2. 5. The heat-and-humidity-resistant LED packaging silica gel according to claim 3, characterized in that, in the methylphenyl hydrogen-containing silicone resin, 0.2<a<0.45, 0.1<b<0.25, 0.1<C<0.35, And the (HMe ₂ SiO _1/2 ) group is a capping group. 6. The heat-and-humidity resistant LED packaging silica gel according to claim 3, characterized in that the refractive index of the methylphenyl vinyl silicone resin is not less than 1.54, the viscosity at 25°C is 5000cps-100000cps; and the molecular weight is 200 -1500, the polydispersity index is less than 1.3, and the mole percentage of molecules with molecular weight less than 500 is less than 1%; The refractive index of the methylphenyl hydrogen-containing silicone resin is not less than 1.54, the viscosity at 25°C is 200cps-5000cps, the molecular weight is 500-1000, and the mass fraction of H is 0.1%-0.6%. 7. The heat-and-humidity-resistant LED packaging silica gel according to claim 1 or 2, wherein the platinum catalyst is selected from the group consisting of: 1,3-divinyl-1,1,3,3-tetramethyldisilica At least one of oxane platinum(0), 1,3-divinyl-1,1,3,3-tetramethyldisiloxane platinum(0), hexachloroplatinum hydride The reaction inhibitor is selected from at least one of ethynyl cyclohexanol, polyvinyl compounds, and silane-modified acetylenic alcohols. 8. The preparation method of the heat-and-humidity-resistant LED encapsulation silica gel described in any one of claims 1-7, is characterized in that, comprises the following steps: Preparation of component A: Mix the raw materials of component A evenly to obtain; Preparation of component B: Mix all the ingredients of component B evenly to get ready. 9. the preparation method of the heat-and-humidity-resistant LED packaging silica gel according to claim 8, is characterized in that, In the step of preparing component A, add each raw material into a blender, stir evenly at room temperature, vacuumize to remove foaming, and obtain; In the step of preparing component B, add each raw material into a blender, stir evenly at room temperature, and vacuumize to remove foaming. 10. The application of the heat-and-moisture-resistant LED encapsulating silica gel described in any one of claims 1-7 in encapsulating LEDs.