KR102595290B1 - Silicone conformal coating composition, silicone cured film prepared therefrom, and use thereof - Google Patents

Abstract

The present invention relates to (a) an alkoxy-terminated polydialkylsiloxane; (b) polydialkylsiloxane having a terminal group containing a (meth)acrylate group and a hydroxy group; (c) dihydroxy-terminated polydialkylsiloxane terminated with hydroxy groups at both ends; (d) curing catalyst; And (e) a photoinitiator; a silicone conformal coating composition comprising a. It relates to a cured film prepared therefrom and its use.

Description

Silicone conformal coating composition, silicone cured film prepared therefrom, and use thereof {Silicone conformal coating composition, silicone cured film prepared therefrom, and use thereof}

The present invention relates to silicone conformal coating compositions, silicone cured films prepared therefrom, and uses thereof.

Conformal coating material is a polymer cured film that protects electronic components while maintaining the outline of a printed circuit board (PCB). Depending on its composition, it can be classified into silicone-based, acrylic-based, urethane-based, and varnish-based. there is. In particular, silicone-based conformal coating materials are widely used because they are stable in a wide range of temperature and humidity conditions and have excellent physical properties such as elasticity, impact resistance, and insulation strength.

On the other hand, room temperature moisture-curable compositions that can form a cured film by reacting with moisture in the air at room temperature are advantageous for application to electrical/electronic devices because they do not require separate heating to cure, and are a silicone-based conformal coating that can be moisture-cured at room temperature. Research to develop is continuing.

However, the conventional moisture-curable silicone-based composition has a slow curing speed, low productivity, and is not suitable for mass production. In addition, in order to increase adhesion to the substrate, the hardness of the cured film decreases and the surface tends to be sticky, and as a result, there is a problem that the cured film is damaged or easily peeled off.

In other words, there is a need to develop a silicone-based composition that has an improved curing speed while maintaining the excellent physical properties of the existing silicone-based cured film, and can simultaneously achieve excellent adhesion to the substrate and improved surface stickiness.

KR 10-2020-0125578 A

The present invention was developed to solve the above-mentioned problems, and provides a silicone conformal coating composition that not only allows room temperature curing when manufacturing a cured film, but also can significantly shorten the curing time.

In addition, the purpose of the present invention is to provide a cured film that can realize excellent physical properties and has improved surface stickiness using the silicone conformal coating composition, and an electronic device including the same.

For the purposes described above, the present invention provides (a) an alkoxy-terminated polydialkylsiloxane having a terminal group represented by the formula (1) below; (b) polydialkylsiloxane having a terminal group containing a (meth)acrylate group and a hydroxy group; (c) dihydroxy-terminated polydialkylsiloxane terminated with hydroxy groups at both ends; (d) curing catalyst; and (e) a photoinitiator. It provides a silicone conformal coating composition comprising a.

[Formula 1]

(In Formula 1 above,

R ₁ is (C1-C10)alkyl or (C2-C10)alkenyl;

R ₂ is (C1-C10)alkyl;

a is an integer of 0 or 1.)

The viscosity of the (a) alkoxy-terminated polydialkylsiloxane measured with a Brookfield viscometer at a temperature of 25°C according to an embodiment of the present invention is 1,000 to 80,000 cps, and the viscosity of (b) polydialkylsiloxane is 100 to 80,000 cps. It is 30,000 cps, and the viscosity of (c) dihydroxy-terminated polydialkylsiloxane may be 1,000 to 80,000 cps.

According to an embodiment of the present invention The terminal group containing the (b) (meth)acrylate group and the hydroxy group may be represented by the following formula (3).

[Formula 3]

(In Formula 3 above,

R ₅ is hydrogen or (C1-C6)alkyl.)

The (b) polydialkylsiloxane according to an embodiment of the present invention may be represented by the following formula (4).

[Formula 4]

(In Formula 4 above,

R ₅ is hydrogen or (C1-C6)alkyl;

R ₁₁ to R ₁₆ are each independently (C1-C6)alkyl;

p is a real number between 1 and 2,000.)

The silicone conformal coating composition according to an embodiment of the present invention may further include an adhesion agent, fumed silica, or a combination thereof.

Additionally, the present invention provides a silicone cured film obtained by photocuring and moisture curing the silicone conformal coating composition.

The ultraviolet-water silicone conformal coating composition according to the present invention not only allows room temperature curing when manufacturing a cured film, but also can achieve a very fast curing speed, and can provide a cured film with excellent physical properties and excellent adhesion to a substrate.

Specifically, the silicone conformal coating composition according to the present invention has a very fast curing speed even at room temperature, so the process time can be shortened, the cost can be reduced, thereby improving economic efficiency, and it can be easily applied to mass production. there is. In addition, the silicone conformal coating composition has excellent flowability and wettability, so it has good workability and can produce a cured film of uniform thickness, as well as improved adhesion between the substrate and the cured film.

In addition, the cured film manufactured from the silicone conformal coating composition not only has excellent adhesion to the substrate, but can also effectively improve the stickiness of the surface of the cured film, solving the problem of damage to the surface of the cured film or easy peeling off. there is.

That is, the silicone conformal coating composition according to the present invention can improve the curing speed problem of the conventional moisture-curable silicone-based composition and simultaneously satisfy the adhesion and physical properties of the cured film produced therefrom.

Hereinafter, the present invention will be described in more detail. Unless otherwise defined, the technical and scientific terms used herein have meanings commonly understood by those skilled in the art to which this invention pertains, and the following description will not unnecessarily obscure the gist of the present invention. Descriptions of possible notification functions and configurations are omitted.

Throughout the specification describing the present invention, the fact that a part "includes" a certain component does not mean that other components are excluded, but may further include other components, unless specifically stated to the contrary. You can.

Unless otherwise specified herein, when a part such as a layer, film, thin film, region, plate, etc. is said to be “on” or “on” another part, this means not only when it is “right on” the other part, but also in between them. It may also include cases where there is another part.

As used herein, the term “hybrid curing” may mean that both curing by light irradiation and curing by moisture are possible.

As used herein, the term “tack free time” may refer to the time until the surface hardens so that the sample does not stick to the pipette or hand.

As used herein, the term “complete curing time” may refer to the time until the center of the cured film is completely cured.

As used herein, the term “(meth)acrylate” may mean both methacrylate or acrylate.

Hereinafter, the present invention will be described in detail.

Room-temperature moisture-curing silicone-based cured films have been widely used because they are stable in a wide range of temperature and humidity conditions, have excellent physical properties such as elasticity, impact resistance, and dielectric strength, and do not require a heating process when manufacturing the cured film. However, conventional moisture-curable silicone-based compositions have a slow curing speed, low productivity, and are not suitable for mass production. In addition, in order to increase adhesion to the substrate, the hardness of the cured film decreases and the surface tends to be sticky, and as a result, there is a problem that the cured film is damaged or easily peeled off.

As a result of extensive research to solve the above problems, the present inventors have found that alkoxy-terminated polydialkylsiloxane; Polydialkylsiloxane having a terminal group containing a (meth)acrylate group and a hydroxy group; dihydroxy terminated polydialkylsiloxane; curing catalyst; and a photoinitiator; when photocuring and moisture curing were performed using a composition containing a photoinitiator, it was discovered that not only could the curing speed be greatly shortened, but also a cured film having excellent physical properties could be provided.

In other words, the composition having the above composition can simultaneously achieve excellent adhesion to the substrate and improved surface stickiness while maintaining superior physical properties compared to conventional moisture-curing silicone-based compositions, and can significantly accelerate the curing speed. discovered and completed the present invention.

Hereinafter, each configuration of the present invention will be described in more detail. However, this is only illustrative and the present invention is not limited to the specific embodiments described as examples.

A silicone conformal coating composition according to an aspect of the present invention includes (a) an alkoxy-terminated polydialkylsiloxane having a terminal group represented by Formula 1 below; (b) polydialkylsiloxane having a terminal group containing a (meth)acrylate group and a hydroxy group; (c) dihydroxy-terminated polydialkylsiloxane terminated with hydroxy groups at both ends; (d) curing catalyst; and (e) a photoinitiator.

[Formula 1]

(In Formula 1 above,

R ₁ is (C1-C10)alkyl or (C2-C10)alkenyl;

R ₂ is (C1-C10)alkyl;

a is an integer of 0 or 1.)

As the silicone conformal coating composition according to one aspect of the present invention includes the above components as components, a chemical reaction such as a curing reaction is induced between the components, thereby providing a cured film that realizes excellent durability. In addition, it is possible to secure excellent adhesion between the cured film and the substrate after curing, and at the same time improve the phenomenon of stickiness remaining on the surface of the cured film. In addition, when manufacturing a cured film, the surface hardening time (tack free time, TFT) and complete curing time can be significantly shortened.

Specifically, the silicone conformal coating composition according to one aspect of the present invention includes (a) an alkoxy-terminated polydialkylsiloxane, (b) a polydialkylsiloxane having a (meth)acrylic group and a hydroxy group, and (c) a dihydroxy-terminated polydialkylsiloxane. By using polydialkylsiloxane together, hybrid curing is possible, which not only significantly shortens the curing time even at low temperatures such as room temperature, but also effectively improves the phenomenon of stickiness remaining on the surface of the cured film after curing is completed. You can.

R ₁ of Formula 1 according to one aspect of the present invention may preferably be (C1-C6)alkyl or (C2-C6)alkenyl, and more preferably (C1-C3)alkyl or (C2-C3)alkenyl. It could be Neil. Additionally, R ₂ may be preferably (C1-C6)alkyl, and more preferably (C1-C3)alkyl.

The (a) alkoxy-terminated polydialkylsiloxane according to one aspect of the present invention may be represented by the following formula (2) as an example.

[Formula 2]

(In Formula 2 above,

R ₁ is (C1-C6)alkyl or (C2-C6)alkenyl;

R ₂ to R ₄ are each independently (C1-C6)alkyl;

a is an integer of 0 or 1;

n is a real number between 1 and 2,000.)

According to one aspect of the present invention, R ₃ and R ₄ may each independently be (C1-C3) alkyl, and the (a) alkoxy-terminated polydialkylsiloxane is more preferably represented by the following formula 2-1: You can.

[Formula 2-1]

(In Formula 2-1 above,

The definitions of R ₁ , R ₂ , a and n are the same as those in Formula 2 above.)

The (a) alkoxy-terminated polydialkylsiloxane according to one aspect of the present invention may be more preferably represented by the following formula 2-2 or 2-3.

[Formula 2-2]

[Formula 2-3]

(In Formulas 2-2 and 2-3,

R is (C1-C6)alkyl;

R' is (C1-C6)alkyl or (C2-C6)alkenyl;

n and m are each independently real numbers from 1 to 1,000.)

In addition, the (a) alkoxy-terminated polydialkylsiloxane according to one aspect of the present invention may have a viscosity value measured with a Brookfield viscometer at a temperature of 25°C of 1,000 to 80,000 cps, preferably 5,000 to 30,000 cps. there is. By satisfying the above viscosity range, not only can workability be improved, but the wettability and flowability of the silicone conformal coating composition can be further improved. Additionally, surface contact with the substrate can be improved, and adhesion between the substrate and the cured film can be further improved.

As an example, the terminal group containing the (b) (meth)acrylate group and the hydroxy group according to one aspect of the present invention may be represented by the following formula (3).

[Formula 3]

(In Formula 3 above,

R ₅ is hydrogen or (C1-C6)alkyl.)

(b) polydialkylsiloxane according to one aspect of the present invention contains both a hydroxy group and a (meth)acrylate group as shown in Chemical Formula 3, and thus can further improve the surface curing rate of the silicone conformal coating composition. In addition, the surface stickiness of the cured film can be more effectively improved after curing. When a vinyl group or an allyl group is included instead of the (meth)acrylate group, stickiness may remain on the surface of the cured film even after it is completely cured, so it is not preferred.

As an example, the (b) polydialkylsiloxane according to one aspect of the present invention may be represented by the following formula (4).

[Formula 4]

(In Formula 4 above,

R ₅ is hydrogen or (C1-C6)alkyl;

R ₁₁ to R ₁₆ are each independently (C1-C6)alkyl;

p is a real number between 1 and 2,000.)

According to one aspect of the present invention, R ₅ may be hydrogen or (C1-C3)alkyl, R ₁₁ to R ₁₆ may each independently be (C1-C3)alkyl, and p is 10 to 2,000. It could be a mistake.

More preferably, the (b) polydialkylsiloxane may be represented by the following formula 4-1.

[Formula 4-1]

(In Formula 4-1 above,

R ₅ is hydrogen or (C1-C3)alkyl;

p is a real number between 1 and 2,000.)

In addition, the (b) polydialkylsiloxane according to one aspect of the present invention may have a viscosity value measured with a Brookfield viscometer at a temperature of 25°C of 100 to 30,000 cps, preferably 500 to 20,000 cps. As the viscosity range is satisfied, the wettability and spreadability of the silicone conformal coating composition according to one aspect of the present invention can be further improved, and the adhesion between the substrate and the cured film can be further improved. Additionally, curing time can also be accelerated.

In addition, the (b) polydialkylsiloxane is not limited, for example, 1 to 20 parts by weight, preferably 100 parts by weight of the (a) alkoxy-terminated polydialkylsiloxane, as long as the purpose of the present invention is achieved. It may contain 5 to 20 parts by weight, more preferably 5 to 15 parts by weight. By including the above-described weight portion of (b) polydialkylsiloxane, the surface curing speed of the polysiloxane composition can be further improved, and a cured film with excellent durability can be provided.

The (c) dihydroxy-terminated polydialkylsiloxane (hereinafter also referred to as 2OH-PDMS) according to one aspect of the present invention may be represented by the following formula (5) as an example.

[Formula 5]

(In Formula 5 above,

R ₂₁ to R ₂₆ are each independently (C1-C6)alkyl;

x is a real number between 1 and 2,000.)

According to one aspect of the present invention, R ₂₁ to R ₂₆ may each independently be (C1-C3)alkyl, and more preferably methyl, but are not limited thereto. Additionally, x may be a real number between 10 and 2,000.

More preferably, the (c) dihydroxy-terminated polydialkylsiloxane may be represented by the following formula 5-1.

[Formula 5-1]

(In Formula 5-1 above,

x is a real number between 1 and 2,000.)

In addition, the (c) dihydroxy-terminated polydialkylsiloxane according to one aspect of the present invention may have a viscosity value of 1,000 to 80,000 cps, preferably 5,000 to 30,000 cps, as measured with a Brookfield viscometer at a temperature of 25°C. It can be. As the viscosity range is satisfied, the workability of the silicone conformal coating composition according to one aspect of the present invention can be further improved and the curing reaction can be effectively promoted.

In addition, the (c) dihydroxy-terminated polydialkylsiloxane is not limited as long as the purpose of the present invention is achieved, for example, 1 to 20 parts by weight relative to 100 parts by weight of the (a) alkoxy-terminated polydialkylsiloxane. parts, preferably 5 to 15 parts by weight. By including the above-mentioned weight parts (b) polydialkylsiloxane, the surface curing speed of the composition can be more effectively shortened.

The curing catalyst (d) according to one aspect of the present invention may be one or two or more selected from organotin compounds, organozinc compounds, organic nickel compounds, zirconium complexes, aluminum complexes, and titanium complexes. The organotin compound is, for example, dibutyltin octoate, dibutyltin dilaurate, dibutyltin di(2-ethylhexanoate), dioctyltin dilaurate, dioctyltin diacetate, dibutyltin dilaurate, dibutyltin dilaurate, and dibutyltin dilaurate. Organotin compounds such as octyltin dioctoate; organic zinc compounds such as zinc octylate and zinc(II) acetylacetonate, and organic nickel compounds such as nickel acetylacetoate and nickel diacetylacetoate; Zirconium complexes such as zirconium tetra(acetylacetonate) and zirconium tetrabutyrate; Aluminum tris(acetylacetonate), aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butylate, aluminum ethylate, ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethylacetoacetate) ), Alkylacetoacetate aluminum diisopropylate, aluminum monoacetylaceto nate bis(ethylacetoacetate), aluminum tris(acetylacetonate), aluminum monoisopropoxymonooleoxyethylacetoacetate, cyclic aluminum oxide isopropylate Aluminum complexes such as cyclic aluminum oxide octylate and cyclic aluminum oxide stearate; Diisopropoxybis(acetylacetonate)titanium, diisopropoxybis(triethanol aminate)titanium, di-n-butoxybis(triethanol aminate)titanium, di(2-ethylhexyloxy)bis(2) -A titanium complex such as ethyl-1,3-hexanediolato)titanium, isopropoxy(2-ethylhexanediolato)titanium, tetraacetylacetonate titanium, and hydroxybis(lactate)titanium; or There may be two or more, but it is not limited to this.

In addition, the curing catalyst (d) may contain 0.05 to 2 parts by weight, preferably 0.05 to 1 part by weight, and more preferably 0.1 to 1 part by weight, based on 100 parts by weight of (a) alkoxy-terminated polydialkylsiloxane. there is. By including the weight part of the curing catalyst, the condensation reaction of the alkoxy group due to moisture can be further promoted without reducing the stability of the composition.

The (e) photoinitiator according to one aspect of the present invention is, for example, one selected from benzophenone-based compounds, triazine-based compounds, benzoin-based compounds, imidazole-based compounds, xanthone-based compounds, phosphine-based compounds, and oxime-based compounds. Or there may be two or more. More specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylanino acetophenone, 2,2-dimethyl Toxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1one, 1-hydroxy cyclohexylphenyl ketone, 2-methyl -1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone , p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2- Methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethylketal, p-dimethylamino benzoic acid one selected from ester, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] and 2,4,6-tmethylbenzoyl-diphenyl-phosphine oxide Or there may be two or more, but it is not limited thereto.

In addition, the (e) photoinitiator may contain 0.05 to 1 part by weight, preferably 0.05 to 0.5 part by weight, and more preferably 0.1 to 0.5 part by weight, based on 100 parts by weight of (a) alkoxy-terminated polydialkylsiloxane. .

The silicone conformal coating composition according to one aspect of the present invention may further include an adhesion imparting agent. The adhesion imparting agent is an alkoxysilane having one or more reactive groups selected from amine groups, thiol groups, and hydroxy groups; dialkyldialkoxysilane; Alkyltrialkoxysilane; tetraalkoxysilane; Or, it may be selected from a combination thereof.

The adhesion imparting agent is, for example, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3 -Aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane and N-2-(aminoethyl)-8-aminooctyltrimethoxysilane, (3-mercaptopropyl )Trimethoxysilane, (3-mercaptopropyl)triethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisoprop Poxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, hexyltrimethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane It may be one or more than one selected from toxin silane, phenyltriisopropoxysilane, tetramethyl ortho silicate, tetraethyl ortho silicate, tetrapropyl ortho silicate, tetrabutyl ortho silicate, and tetrapentyl ortho silicate. It is not limited.

In addition, the adhesion imparting agent may contain 0.01 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of (a) alkoxy-terminated polydialkylsiloxane. By further including the weight portion of the adhesion agent, effects such as shortening the curing time of the silicone conformal coating composition, improving the durability of the cured film, and improving the surface stickiness phenomenon can be more effectively improved.

The silicone conformal coating composition according to one aspect of the present invention may further include an inorganic filler. The inorganic filler is not particularly limited as long as it is an inorganic filler used in this field, but for example, it may be one or two or more selected from silica, talc, titanium dioxide, aluminum oxide, calcium carbonate, aluminum silicate, magnesium silicate, and zirconium oxide. and preferably silica, but is not limited thereto. Specifically, the silica may include precipitated silica or fumed silica, and it may be more preferable to use fumed silica.

In addition, when using the above inorganic filler, the content is not particularly limited as long as it achieves the purpose of the present invention, but for example, 1 to 20 parts by weight based on 100 parts by weight of (a) alkoxy-terminated polydialkylsiloxane. It may include By further including an inorganic filler in the above weight range, the viscosity and storage stability of the silicone conformal coating composition can be more easily controlled, and the mechanical properties of the cured film formed after curing can be further improved.

In addition, the present invention may further include hexaalkyldisilazane as a reaction accelerator. The reaction accelerator traps alcohol, a side reactant, in the condensate to react, thereby promoting the overall curing reaction in the forward direction and improving physical properties. It's good because it's an inducement. Preferably, it is preferable to use the same or less equivalent weight of the alkoxy group of component (a), so its content is not limited. Preferably, it may contain 0.5 to 10 parts by weight based on 100 parts by weight of the (a) alkoxy-terminated polydialkylsiloxane. By further including a reaction accelerator in the above weight range, a synergistic effect can be provided in shortening the surface curing time of the silicone conformal coating composition.

The silicone conformal coating composition according to one aspect of the present invention may be in an anhydrous state, and therefore, a curing reaction by moisture can be easily performed later under humidified conditions.

Additionally, the silicone conformal coating composition according to one aspect of the present invention can be used as a conformal coating agent, and preferably can be used as a conformal coating agent for electronic devices.

In addition, one aspect of the present invention provides a silicone cured film obtained by photocuring and moisture curing the silicone conformal coating composition and an electronic device including the same.

The electronic device is not particularly limited, but may be an electronic device including an electric circuit or electrode, for example, a resistor, capacitor, transistor, diode, amplifier, relay, transformer, battery, fuse, integrated circuit, switch, LED. , antennas and oscillators, etc.

Of course, any method for manufacturing the silicone cured film according to one aspect of the present invention can be any known method within the range recognized by a person skilled in the art.

Hereinafter, a method of forming a silicone cured film using the silicone conformal coating composition will be described in detail.

A silicone cured film according to an aspect of the present invention includes the steps of (A) applying the silicone conformal coating composition to a substrate at a relative humidity of 30 to 90%; and (B) photocuring and moisture curing through light irradiation.

The production of the silicone cured film according to one aspect of the present invention may be performed at 10 to 50°C, preferably at 10 to 30°C, and more preferably at 20 to 30°C. That is, the silicone conformal coating composition according to one aspect of the present invention can be cured even at a low temperature such as room temperature and does not require heating during curing, so it can be used as a sealant, adhesive, or coating agent for electrical and electronic devices. In addition, process equipment and manufacturing processes can be simplified, thereby improving economic efficiency.

In step (A) according to an aspect of the present invention, a conventional coating method may be used, and specific examples include a spray method, a roll coater method, a rotational coating method, and a spin coater method, but are not limited thereto. Additionally, the substrate may be made of silicon, quartz, glass, silicon wafer, polymer, metal, or metal oxide, but is not limited thereto.

Additionally, the relative humidity may be 30 to 90%, preferably 40 to 90%, and more preferably 50 to 80%. Under the above-mentioned humidity conditions, the curing reaction by moisture can proceed more easily.

The light source for photocuring in step (B) according to an aspect of the present invention may be selected from visible light, ultraviolet rays, deep ultraviolet rays, electron beams, : 436 nm), h-ray, i-ray (wavelength: 365 nm), etc. can be used, and of course, the irradiation amount of these ultraviolet rays can be appropriately selected according to need. More specifically, the light irradiation may be performed using a high-pressure mercury lamp.

Of course, the thickness of the silicone cured film according to one aspect of the present invention may be appropriately changed depending on the purpose, but may preferably be formed to a thickness of 0.1 ㎛ to 2,000 ㎛, preferably 1 ㎛ to 1,000 ㎛, and further. Preferably, it can be formed to have a thickness of 10 ㎛ to 500 ㎛.

Hereinafter, an embodiment will be described to specifically explain the present invention, but the present invention is not limited to the following embodiment.

[Preparation Example 1] Preparation of room temperature moisture curing PDMS (AK-3M)

A four-neck 3L reactor equipped with a mechanical stirrer, cooling condenser, nitrogen injection device, and thermometer was sufficiently purged with nitrogen gas. Afterwards, 500g of 5,000cps OH-PDMS (hydroxyl terminated polydimethylsiloxane, YF70C-0.5M), 1,500g of 20,000cps OH-PDMS (YF70C-2M), and 38.66g of TMOS (tetramethylorthosilicate) were added and incubated at 30°C for 10 minutes. It was thoroughly mixed by stirring. 0.38 g of sodium methylate (30% solution in methanol) was added to the mixture, and stirred for 30 minutes while maintaining the temperature of the reactor at 30°C. After taking 10 g of the reaction solution, a tetra-n-butyl titanate (Tyzor TnBT) reaction test was performed to confirm that no hydroxyl functional group was present, and then the reaction was terminated. After completion of the reaction, it was neutralized and cooled with 0.11 g of 99% formic acid at room temperature (25°C), then high-vacuum distilled to remove unreacted substances and filtered through a 200-mesh wire mesh to produce room-temperature moisture-curable PDMS with a viscosity of 15,800 cps. The compound AK-3M was obtained.

[Preparation Example 2] Preparation of room temperature moisture curing PDMS (AK-M2M)

AK-M2M with a viscosity of 15,700 cps was obtained in the same manner as Preparation Example 1, except that 27.24 g of MTMS (Methyltrimethoxysilane) was used instead of 38.66 g of TMOS (tetramethylorthosilicate).

[Preparation Example 3] Preparation of room temperature moisture curing PDMS (AK-V2M)

AK-V2M with a viscosity of 16,050 cps was obtained in the same manner as Preparation Example 1, except that 27.24 g of VTMS (vinyltrimethoxysilane) was used instead of 38.66 g of TMOS.

[Preparation Example 4] Preparation of UV-curable PDMS (MAT-PDMS)

A four-neck 3L reactor equipped with a mechanical stirrer, cooling condenser, nitrogen injection device, and thermometer was sufficiently purged with nitrogen gas. After that, 1,000 g of HT-PDMS (Korea Biogen, RF HD 0080, H content 0.093 mmol/g), 11.1 g of AGE (Allyl gylcidyl ether), 10 g (1 wt%) of platinum catalyst, and 1,000 g of toluene were added. The mixture was stirred at 130°C for 50 minutes while maintaining a nitrogen atmosphere. FT-IR was measured to confirm that the Si-H peak (2140 cm ^-1 ) disappeared, and the reaction was terminated to obtain ET-PDMS. After that, 8.6 g of MAA (Methacrylic acid) was added and reacted at 110° C. for 4 hours. Unreacted products and solvents were removed by distillation under reduced pressure and filtered through a 200 mesh wire mesh to obtain MAT-PDMS with a viscosity of 1,100 cps.

[Preparation Example 5] Preparation of UV-curable PDMS (AT-PDMS)

AT-PDMS with a viscosity of 1,080 cps was obtained in the same manner as Preparation Example 4, except that 7.2 g of AA (Acrylic acid) was used instead of 8.6 g of MAA.

[Example 1]

Preparation of Silicone Conformal Coating Compositions

After adding 1,955 g of room temperature moisture curing PDMS (AK-3M PMDS) and 175 g of silicone oil (PDMS Oil, 100 cPs) prepared in Preparation Example 1 to the mixing tank, the tank was mounted on a stirrer and mixed for 30 minutes at room temperature (25°C). After stirring for a minute, 250 g of fumed silica (KONASIL, K-P15) was added and stirred for an additional 30 minutes. Afterwards, 25 g of 3-Aminopropyltrimethoxysilane (ATPMS,) and 37.5 g of Methyltrimethoxysilane (MTMS) were added as adhesion agents, stirred for 30 minutes, and then washed with an alcohol scavenger. 50 g of hexamethyldisilazane (HMDZ) and 7.5 g of dibutyltin dilaurate (DBTDL) as a curing catalyst were added and stirred for 30 minutes. Afterwards, 100 g of UV curable PDMS (MAT-PDMS) prepared in Preparation Example 4, 150 g of dihydroxy-terminated PDMS (2OH-PDMS, 15,000 cPs), and 5 g of benzyl dimethyl Ketal (BDK) as a photoinitiator were added. After stirring for 30 minutes, the silicone conformal coating composition of Example 1 was obtained by quickly packaging it into a defined cartridge. The physical properties are listed in Table 2 below.

Manufacturing of silicone cured film

Under conditions of 50% relative humidity, room temperature (25°C), and nitrogen atmosphere, the silicone conformal coating composition prepared above was coated to a thickness of 0.2 mm on a glass substrate. Afterwards, it was irradiated with light for 30 seconds using a high-pressure mercury lamp (1 kW, Philips), left at room temperature, and the surface curing time (ASTM C679) and complete curing time were measured, and a silicone cured film was manufactured.

[Examples 2 to 7]

Except for using the polydimethylsiloxane (PDMS) compound and photoinitiator content of Examples 2 to 7 shown in Table 1 below, the same procedure as Example 1 was performed, and the physical properties are shown in Table 2 below.

[Comparative Example 1]

The room temperature moisture-curable silicone-based composition of Comparative Example 1 was prepared in the same manner as Example 1, except that UV-curable PDMS (MAT-PDMS), 2OH-PDMS, and photoinitiator (BDK) were not used, and the physical properties were is listed in Table 2 below.

Room temperature moisture hardening PDMS UV-curable PDMS 2OH-PDMS photoinitiator type Content (g) type Content (g) Content (g) Content (g) Example 1 AK-3M 1,955 MAT-PDMS 100 100 5 Example 2 AK-3M 1,955 MAT-PDMS 100 200 5 Example 3 AK-3M 1,955 MAT-PDMS 200 100 10 Example 4 AK-3M 1,955 MAT-PDMS 300 100 15 Example 5 AK-3M 1,955 AT-PDMS 300 100 15 Example 6 AK-M2M 1,955 MAT-PDMS 300 100 15 Example 7 AK-V2M 1,955 MAT-PDMS 300 100 15 Comparative Example 1 AK-3M 1,955 - - -

Surface hardening time (min) Full curing time (h) Example 1 3 20 Example 2 2 18 Example 3 One 12 Example 4 One 5 Example 5 One 5 Example 6 One 5 Example 7 One 3 Comparative Example 1 11 51

As shown in Table 2 above, it can be seen that the curing time of the silicone conformal coating composition according to the present invention is significantly shortened. Specifically, although the conventional moisture-curable silicone-based composition can realize excellent physical properties after curing, the curing speed is slow, and when improving adhesion to the substrate, the hardness of the cured film decreases and stickiness occurs on the surface. However, it can be seen that the composition according to the present invention, compared to Comparative Example 1, can secure the excellent physical properties of the existing silicone-based cured film and at the same time significantly improve the curing speed.

In other words, the silicone conformal coating composition according to the present invention can shorten the process time, reduce the cost, improve economic efficiency, can be easily applied to mass production, and has the adhesive strength of the cured film manufactured therefrom. and physical properties can be satisfied at the same time.

Claims (6)

(a) alkoxy-terminated polydialkylsiloxane having a terminal group represented by the following formula (1); (b) polydialkylsiloxane represented by the following formula (4); (c) dihydroxy-terminated polydialkylsiloxane terminated with hydroxy groups at both ends; (d) curing catalyst; And (e) a photoinitiator; a silicone conformal coating composition comprising a.
[Formula 1]

[Formula 4]

In Formulas 1 and 4,
R ₁ is (C1-C6)alkyl or (C2-C6)alkenyl;
R ₂ is (C1-C6)alkyl;
a is an integer of 0 or 1;
R ₅ is hydrogen or (C1-C6)alkyl;
R ₁₁ to R ₁₆ are each independently (C1-C6)alkyl;
p is a real number between 1 and 2,000. According to clause 1,
The viscosity of the (a) alkoxy-terminated polydialkylsiloxane measured with a Brookfield viscometer at a temperature of 25°C is 1,000 to 80,000 cps, (b) the viscosity of the polydialkylsiloxane is 100 to 30,000 cps, and (c) A silicone conformal coating composition, wherein the hydroxy terminated polydialkylsiloxane has a viscosity of 1,000 to 80,000 cps. delete delete According to clause 1,
The silicone conformal coating composition further includes an adhesion agent, fumed silica, or a combination thereof. A silicone cured film obtained by photocuring and moisture curing the silicone conformal coating composition of any one of claims 1, 2, and 5.