WO2010003278A1

WO2010003278A1 - Anti-flaming packaging material for electronic element

Info

Publication number: WO2010003278A1
Application number: PCT/CN2008/001509
Authority: WO
Inventors: 高卫国; 张艳飞
Original assignee: 天津市凯华绝缘材料有限公司
Priority date: 2008-07-10
Filing date: 2008-08-22
Publication date: 2010-01-14
Also published as: CN101302343A

Abstract

The invention provides an anti-flaming packaging organic silicon resin material used for electronic element, the components and weight percentage thereof are as follows: 15-60wt% of organic silicon resin, 20-80wt% of filling material, 1-20wt% of plasticizer, 0.5-1.5wt% of catalyst, 0.5-5 wt% of assistant and 0.5-5wt% of pigment. The material of the invention has the following advantages: no-environment pollution, high temperature resistance, excellent flame retardance, low cure temperature, self-leveling and good electrical insulating property etc. And it is suitable for packaging of electronic elements such as piezo resistor, thermal resistor and ceramic capacitor and the like.

Description

Flame-retardant packaging material for electronic components

The present invention relates to a flame-retardant encapsulating material for electronic components. Specifically, the present invention relates to a silicone resin flame-retardant encapsulating material for electronic components, and belongs to the technical field of electronic component packaging materials. Background technique

After the electronic components are manufactured and tested, it is necessary to coat the surface of these chips with a high-strength, insulating and moisture-proof coating. The quality and performance of this coating is critical to the quality of electronic components. Impact. Nowadays, such coating materials generally use epoxy powder encapsulating materials, which have good adhesion, high mechanical properties and low cost, and can achieve UL94-V0 flame retardant level. Despite this, when the electronic components are subjected to an instantaneous overload voltage, the enormous heat generated can still ignite the epoxy encapsulating material. Although the halogen flame retardant and the lanthanide synergist are used to cause the combustion to terminate spontaneously after a certain period of time, under certain circumstances, it is still a fire hazard, and the halogenated flame retardant tends to generate a large amount when burning. The highly carcinogenic substance - polybrominated dibenzodioxane and polybrominated dibenzofuran, is extremely harmful. Therefore, in view of the many challenges faced by epoxy encapsulants, it is necessary to develop a flame-retardant electronic packaging material using environmentally friendly flame retardants.

Silicone resin is a material with both mechanical and inorganic properties. It has excellent electrical properties, high dielectric strength and electrical resistivity, low dielectric loss, and little variation over a wide range of temperatures and frequencies. It performs well in heat resistance, weather resistance, water repellency, and flame retardancy, and is suitable for packaging materials. In addition, the low carbon content of methyl silicone resin has excellent non-combustible properties, and it does not need to add flame retardant to have non-combustible properties. The silicone resin with slightly higher carbon content needs to add a small amount of environmentally friendly flame retardant to achieve resistance. Combustion performance. Solvent-based coating products using silicone resins as base materials have been used for insulation encapsulation of electronic components and have achieved good results. Among them, xylene is commonly used as a solvent. It is well known that xylene is a toxic and flammable organic solvent, which is harmful to operators and the environment. Therefore, it is difficult to obtain widespread application.

The silicone resin encapsulating material can better solve the above problems. The powder coating is produced by the melt extrusion method, and the organic solvent is not used in the production and use process, and the flame retardant is safe and environmentally friendly or does not need to be added with a flame retardant.

European Patent EP 0 950 695 A1 discloses a silicone resin composition which can be used for heat-resistant coatings, but has the following disadvantages when used for packaging coatings: (1) The thickness of the coating film can only reach several tens of micrometers, and excessive thickness tends to cause cracking and peeling of the coating film. The thickness of the coating film formed by the surface encapsulation material of the electronic component should be at least 300 μm _; (2) the curing temperature exceeds 230 ° C, and the heat resistance temperature of the electronic component generally does not exceed 180 ° C, otherwise the solder joint may fall off. public account For the Chinese patent application of CN101163748A, a silicone encapsulant is mentioned, and the product is formed by heat molding, and self-leveling by heating cannot be achieved. Summary of the invention

The technical problem to be solved by the present invention is to provide a flame-retardant encapsulating material for electronic components according to the deficiencies of the prior art, wherein the encapsulating material is mainly composed of a silicone resin, which is environmentally friendly, high temperature resistant, flame retardant, and cured. Low temperature, self-leveling, good electrical insulation and so on.

The technical problem to be solved by the present invention is achieved by the following technical solutions:

A flame-retardant encapsulating material for electronic components, each component and its weight percentage range are: silicone resin 15-60%;

Filler 20-80%;

Plasticizer 1-20%;

Catalyst 0.5-1.5%;

Additive 0.5-5%;

Pigment 0.5-5%.

Further, a pigment and a flame retardant may be added to the constituent components, wherein the flame retardant is added in an amount of from 0 to 30% by weight based on the weight of the filler. The type and amount of the pigment are selected according to the color, such as: carbon black.

Further, the silicone resin is obtained by polymerizing one or more of the organochlorosilane monomers having the following structure, or by first oxidizing and then performing a polymerization reaction by an alcoholysis reaction. Three-dimensional crosslinked structure of solid polysiloxane:

Me _m SiCl _n or Ph _x SiCl _y , where m+n=4, m=0-3, x+y=4, x=l, 2, m, n, x and y should be integers.

Moreover, the property parameter of the silicone resin is such that the weight content of the phenyl group and the methyl group should be <50%, preferably <30%; and the molar ratio of the phenyl group to the methyl group is between 0-5: 1, preferably 0.2-3.3: 1; glass transition temperature Tg>45. C.

Moreover, the filler is at least one material selected from the group consisting of silicon micropowder, talc, mica powder, wollastonite powder and BaSO ₄ , at least one or any combination of several of them.

Moreover, the plasticizer is at least one material selected from the group consisting of silicone rubber, silicone oil, silane, at least one or any combination of several of them.

Moreover, the catalyst is at least one material selected from the group consisting of: an organic acid complex of divalent zinc, acetyl propyl The ketone aluminum, 12-aminododecanoic acid, p-toluenesulfonic acid or a salt thereof, a quaternary ammonium salt or any combination thereof may preferably be a combination of aluminum acetylacetonate and 12-aminododecanoic acid.

Further, the auxiliary agent is at least one selected from the group consisting of at least one of an auxiliary agent such as an adhesion promoter, an antifoaming agent, a leveling agent, a wetting agent, and a brightener.

Moreover, the flame retardant may be selected from environmentally friendly flame retardants known in the prior art, such as: Al(OH) ₃ , Mg(OH) ₂ , zinc borate, ammonium polyphosphate having a degree of polymerization greater than 100, and trimeric europium At least one or a combination of several of the amine cyanurates.

Further, the pigment may be a commercially available inorganic or organic pigment having a heat-resistant temperature of 200 ° C or more and which does not adversely affect the encapsulating material.

Another technical problem to be solved by the present invention is to provide a method for preparing a flame-retardant encapsulant for electronic components according to the deficiencies of the prior art, which comprises applying the components of the composition to the technical field of the art. Common equipment and methods are fully mixed and dispersed. For example: After mixing uniformly, it is melt extruded at a certain temperature in a twin-screw extruder to obtain a composition of the present invention.

The advantages and positive effects of the present invention are:

(1) The silicone resin encapsulating material does not use any organic solvent during production, processing and use, and is safe and environmentally friendly;

(2) The silicone resin encapsulating material uses an environmentally friendly and harmless flame retardant, or can achieve a flame retardant effect without adding a flame retardant, and does not produce a substance harmful to the human body or the environment when burned or burned by a flame. ;

(3) The silicone resin encapsulating material is capable of heating self-leveling and forming a continuous glossy encapsulation layer;

(4) The curing temperature of the silicone resin encapsulating material is lower than 180 ° C, and is suitable for use with electronic components having solder joints;

<5) The invention has the characteristics of environmental protection, high temperature resistance, flame retardancy, low curing temperature, self-leveling heating, good electrical insulation performance, etc., and is used for encapsulation of electronic components such as varistor, thermistor and ceramic capacitor. . detailed description

The invention is further described in detail below with reference to the specific embodiments. The following examples are merely illustrative and not limiting, and the scope of the invention is not limited thereto.

First, the constituent components of the present invention are described as follows:

1. Silicone resin:

Prepared from one or more of organochlorosilane monomers having the following structure:

Me _m SiCl _n or Ph _x SiCiy, where m+n=4, m=0-3, x+y=4, x=l, 2, m, n, x and y should Is an integer.

One or more of the above monomers are subjected to a polymerization reaction, or alkoxylation is carried out by an alcoholysis reaction followed by a polymerization reaction to obtain a solid polysiloxane having a three-dimensional crosslinked structure.

Its structural formula can be expressed as follows, but is not limited to this expression -

Wherein, R-methyl or phenyl groups, dashed lines represent omitted repeating units.

The weight content of the phenyl group and the methyl group in the solid polysiloxane should be <50%, preferably <30%, and the lower the content, the better the flame retardancy; the molar ratio of the phenyl group to the methyl group is between 0-5: 1, preferably 0.2-3.3: 1, the higher the phenyl content, the slower the curing speed of the paint film, and the lower the flame retardancy, but the advantageous side is to improve the toughness of the paint film. The higher the temperature and the thermal shock impact resistance; the glass transition temperature Tg>45 ° C, to ensure that the powder material will not agglomerate at room temperature. Silicone resin products that meet the above requirements are Dowcoming® 220, 233, 249, Z-6018 from Dowcoming, USA, Silres® 604, 610 from Wacker, Germany. The content of the silicone resin is 15-60%, preferably 20-55%.

2. Filler: The filler may be at least one of silicon fine powder, talc powder, mica powder, wollastonite powder, BaS0 ₄ , or the like, and the particle size is between 150 mesh and 3000 mesh, preferably 200 mesh. -800 mesh. When the thickness of the coating exceeds 300μηη, in order to avoid cracking, it is necessary to add mica powder or wollastonite to mix with plasticizer. The lamellar structure of mica powder and the rod-like structure of wollastonite can play the role of reinforcing ribs in the coating film. To avoid cracking of the coating film. In addition, talc can improve the toughness of the film. The content of the filler is 20-80%, and for the filler having a large specific gravity, such as wollastonite powder, BaS0 ₄ , preferably 50-60%.

3. Plasticizer:

Plasticizers are generally used to improve the brittleness of silicone materials, improve the toughness of the coating film, and are less prone to cracking. Depending on the type, the amount may be from 1 to 20%, and may be silicone rubber, silicone oil, silicon germanium or the like which is compatible with the solid silicone, and one or a combination of them may be used in the present invention. 4. Catalyst - The catalyst is generally a complex of divalent zinc such as zinc octoate or zinc stearate with high catalytic activity, aluminum acetylacetonate, 12-aminododecanoic acid, p-toluenesulfonic acid and its salt or quaternary ammonium salt. Preferably, the aluminum acetylacetonate and the 12-aminododecanoic acid composition are catalytically active to catalyze the reaction of the silicone resin between 120 and 170 ° C, and the amount of the catalyst is 0.5 to 1.5%.

5. Auxiliaries:

Additives include adhesion promoters, as well as defoamers, leveling agents, wetting agents, brighteners and other functional additives commonly used in powder coatings; adhesion promoters help to improve the adhesion of the coating film to the substrate. Force, defoamer is used to remove small molecules of volatiles generated during the curing reaction. The leveling agent helps the coating to form a dense, continuous, smooth coating, such as Exytront A-4 and Resiflow P-67 from Estron Chemical Inc. Wait. The total amount of additives is 0.5-5%.

6. Flame Retardant - The flame retardancy of silicone resin varies with the content of hydrocarbon groups such as methyl or phenyl. When the content of hydrocarbon group is high, the flame retardancy is poor, in order to ensure the flame retardancy of the packaging material. To achieve UL-94 V0 level, a flame retardant is required. Flame retardants are selected from the flame retardants known in the prior art, especially several environmentally friendly flame retardants which have been commercialized, such as: Al(OH)3, Mg(OH) ₂ , zinc borate, degree of polymerization greater than 100 A combination of one or more of ammonium polyphosphate or melamine cyanurate. It is generally believed that its flame retardant mechanism absorbs a large amount of heat, and it liberates crystallization water or inert gas to dilute the combustible gas. The first three flame retardants can also be thermally crosslinked to form a dense inorganic protective film, so that oxygen can not enter the inside of the coating film. Flame retardant effect. The flame retardant may be used in an amount of from 0 to 30% by weight based on the total amount of the filler.

7. Pigments:

The pigment may be a commercially available inorganic or organic pigment having a heat-resistant temperature of 200 ° C or higher and having no adverse effect on the encapsulating material.

Example 1

Flame-retardant silicone resin encapsulating material for electronic components, each component and its weight fraction are respectively

10 copies of Dowcorning® 220;

Silres® 610 40 servings;

107 silicone oil (viscosity 5000cs) 2 parts;

1 part of aluminum acetylacetonate;

12-aminododecanoic acid 0.3 parts;

Silicon micropowder (325 mesh) 50 parts;

Dowcorning® Z-6040 0.1 parts; Oxymelt A-4 0.5 parts;

1 Resiflow P-67;

Carbon black 0.1 parts.

The preparation method is:

All of the above components were uniformly dispersed in a high-mixing pot, melt-extruded in a twin-screw extruder, and then cooled to obtain a finished product.挤出Use the extruder to control the temperature in two zones, ί60°C, Π80°C, screw speed 180rpm. It should be noted that if the temperature is too high or the screw speed is too slow, it is easy to cause a curing reaction between the components in the extruder, and the powder can no longer be leveled. Example 2:

A flame-retardant silicone resin encapsulating material for electronic components, each component and its parts by weight are respectively -

10 copies of Dowcorning 220;

Silres® 610 40 servings;

107 silicone oil (viscosity 5000cs) 2 parts;

1 part of aluminum acetylacetonate;

12-aminododecanoic acid 0.3 parts; '

Silicon micropowder (325 mesh) 30 parts;

Mica powder (325 mesh) 20 parts;

Dowcorning® Z-6040 0.1 parts;

Oxymelt A-4 0.5 parts;

1 Resiflow P-67;

Carbon black 0.1 parts.

The preparation method is the same as in Example 1. Example 3:

A flame-retardant silicone resin encapsulating material for electronic components, each component and its parts by weight are:

Silres® 604 50 servings;

107 silicone oil (viscosity 5000cs) 2 parts;

1 part of aluminum acetylacetonate;

0.5 parts of 12-aminododecanoic acid; Silicon micropowder (325 mesh) 30 parts;

Mica powder (325 mesh) 20 parts;

Dowcorning® Z-6040 0.1 parts;

Oxymelt A-4 0.5 parts;

1 Resiflow P-67;

Carbon black 0.1 parts.

The preparation method is the same as that in the first embodiment. Example 4:

Silres® 604 50 servings;

107 silicone oil (viscosity 5000cs) 2 parts;

1 part of aluminum acetylacetonate;

12-aminododecanoic acid 0.5 parts;

Mica powder (325 mesh) 20 parts;

30 parts of Mg(OH) ₂ ;

Dowcorning® Z-6040 0.1 parts;

Oxymelt A-4 0.5 parts;

1 Resiflow P-67;

Carbon black 0.1 parts.

The preparation method is the same as in Example 1.

The composition of the raw materials of the examples is summarized as follows:

Example 1 2 3 4 Raw material Dowcorning® 220 10 10

Silicone

Proportion Silres® 604 50 50 Resin

Silres® 610 40 40

Plasticizer 107 Silicone oil (viscosity 5000c.s) 2 2 2 2 Aluminum acetylacetonate 1 1 1 1 Catalyst

12-aminododecanoic acid 0.3 0.3 0.5 0.5 Filled silicon micropowder (325 mesh) 50 30 30 Mica powder (325 mesh) 20 20 20

Mg(OH) ₂ 30

Dowcorning® Z-6040 0.1 0.1 0.1 0.1 Additive Oxymelt A-4 0.5 0.5 0.5 0.5

Resiflow P-67 1 1 1 1 Pigment Carbon black 0.1 0.1 0.1 0.1 Preparation Extrusion conditions Zone I 60 Ό , Zone II 80 ° C Condition Screw speed 180 rpm

Note: Both Oxymelt A-4 and Resiflow P-67 are Estron Chemical Ine products.

The beneficial effects of the present invention are further verified by specific test results below:

The product obtained above was taken, and 100 mesh - 325 mesh powder was collected after pulverization, and tested in accordance with the method of SJ20633-1997.

When it is required to test with electronic components such as varistor, thermistor, ceramic capacitor, etc., the preheating temperature of the electronic component and the leveling temperature of the powder are both 160 ° C, and the number of coatings is determined according to the thickness of the coating film. The film thickness is controlled at 300-350 μm; the curing condition is 140 ° C, 20 min.

Note: 1, 160 ° C leveling; 2, temperature cycle _{condition: -40 ° C x30min; -25 °} C x l5min; -85 ° C x30min; then repeated.

In summary, the silicone resin encapsulating material provided by the invention does not use any organic solvent during production, processing and use, and is safe and environmentally friendly; the use of environmentally friendly and harmless flame retardant, or the addition of a flame retardant can be achieved Flame-retardant effect, and does not produce harmful substances to the human body or the environment when burned or burned by flame; can heat self-leveling and form a continuous glossy encapsulation layer; the curing temperature of the encapsulating material is lower than 180 ° C, Suitable for use with electronic components with solder joints; the invention has the characteristics of environmental protection, high temperature resistance, flame retardancy, low curing temperature, self-leveling by heating, good electrical insulation performance, etc., and is used for varistor, thermistor, ceramic Encapsulation of electronic components such as capacitors. It should be noted that the above embodiments are only intended to illustrate the invention and are not to be construed as limiting the scope of the invention. The spirit and scope of the invention are intended to be included within the scope of the appended claims.

Claims

Claim

A flame-retardant encapsulating material for electronic components, characterized in that: each constituent component and its weight percentage range are:

Silicone resin 15-60%;

Filler 20-80%;

Plasticizer 1-20%;

Catalyst 0.5-1.5%;

Additive 0.5-5%:

Pigment 0.5-5%.

2. The flame-retardant encapsulating material for electronic components according to claim 1, wherein: the pigment is a commercially available inorganic or organic pigment that does not adversely affect the encapsulating material, and has a heat resistance temperature of 200°. Above C.

The flame-retardant encapsulating material for an electronic component according to claim 1, wherein a flame retardant is further added to the constituent component, wherein the flame retardant is added in an amount of from 0 to 30% by weight based on the weight of the filler.

The flame-retardant encapsulating material for electronic components according to claim 3, wherein the flame retardant is Al(OH)3, Mg(OH) ₂ , zinc borate, polyphosphoric acid having a degree of polymerization greater than 100 At least one of ammonium, melamine cyanurate.

The flame-retardant encapsulating material for an electronic component according to any one of claims 1 to 4, wherein the silicone resin is polymerized by using one or more of organochlorosilane monomers having the following structure. Or alkoxylation by alcoholysis reaction followed by polymerization to obtain a solid polysiloxane having a three-dimensional crosslinked structure:

Me _m SiCl _n or Ph _x SiCl _y , where m+n=4, m-0-3 , x+y=4, x-1 , 2, and m, n, x and y should be integers.

The flame-retardant encapsulating material for electronic components according to claim 5, wherein: the property parameter of the silicone resin is that the weight content of the phenyl group and the methyl group should be <50%, preferably < 30%; molar ratio of phenyl group to methyl group is 0-5:1, preferably 0.2-3.3:1; glass transition temperature Tg>45 °C.

The flame-retardant encapsulating material for electronic components according to any one of claims 1 to 4, wherein the filler is at least one of silicon fine powder, talc powder, mica powder, wollastonite powder, and BaS0 ₄ .

The flame-retardant encapsulating material for an electronic component according to any one of claims 1 to 4, wherein the plasticizer is at least one of silicone rubber, silicone oil, and silane.

The flame-retardant encapsulating material for electronic components according to any one of claims 1 to 4, wherein the catalyst is an organic acid complex of divalent zinc, or aluminum acetylacetonate or 12-aminododecanoic acid. Or p-toluenesulfonic acid And a salt thereof, or a quaternary ammonium salt, preferably a combination of aluminum acetylacetonate and 12-aminododecanoic acid.

The flame-retardant encapsulating material for an electronic component according to any one of claims 1 to 4, wherein the auxiliary agent is at least one of an adhesion promoter, an antifoaming agent, and a leveling agent.