KR102695839B1 - Super soft moisture-curable water-resistant coating agent composition and super soft moisture-curable water-resistant coating agent comprising the same - Google Patents

Abstract

The present invention relates to a moisture-curable conformal coating composition that enables connector connection even after application to a printed circuit board assembly due to the ultra-soft properties of the resin.

Description

Super soft moisture-curable water-resistant coating agent composition and super soft moisture-curable water-resistant coating agent comprising the same

The present invention relates to an ultra-soft moisture-curable waterproof coating composition and an ultra-soft moisture-curable waterproof coating comprising the same, and more specifically, to an ultra-soft moisture-curable waterproof coating composition capable of connector connection even after application to a printed circuit board assembly due to the ultra-soft properties of a resin, and an ultra-soft moisture-curable waterproof coating comprising the same.

As the gaps between devices mounted on the board in printed circuit board assemblies or the leads thereof become closer together, the movement of ions between the leads or the occurrence of short circuits due to whiskers, etc., due to external environmental factors such as foreign substances, contamination, and moisture are becoming major problems. To address this, conformal coating, which coats the leads with a moisture-resistant resin to completely block the leads from the atmospheric environment, is being performed.

In order to provide waterproofing and dustproofing functions to the internal devices of most electronic devices, a structural sealing method using rubber packing and silicone is used. This method directly prevents water or contaminants from entering the electronic device, but in any case, if water penetrates into the electronic device, it cannot prevent the device from breaking down due to current conduction between semiconductor devices in the printed circuit board assembly.

In order to solve these problems, a waterproof coating agent must be introduced. However, conventional conformal coating agents have a high modulus of resin and do not take into account the special situation in which a connector must be connected after coating, resulting in insufficient ease of connector attachment and problems in which current does not flow after connection.

Currently, in the case of conformal coating agents for printed circuit boards, a method is adopted in which the surrounding area is coated after the connector and semiconductor device are connected, or a method is adopted in which a dam is created around the connector area with a coating agent in advance and then the semiconductor device is connected. However, if moisture enters due to poor adhesion of the conformal coating agent or moisture infiltration through pores, there is still a possibility that defects may occur in the semiconductor device. In addition, as current mobile devices are becoming foldable, flexible, and rollable, there is a need to supplement the waterproofing properties of the hinge area, which is vulnerable to moisture infiltration.

KR 10-0193014 B1

The present invention provides an ultra-soft moisture-curable waterproof coating composition that enables the connection of semiconductor devices even after coating on a connector portion of a printed circuit board, as deformation (pushing phenomenon and puncturing phenomenon) of the resin can easily occur even under a very small force (20 gf).

In addition, the present invention provides an ultra-soft moisture-curable waterproof coating composition that can easily cause deformation of the resin even under a very small force (20 gf), while maintaining contamination resistance and waterproofness that can be used as a waterproof coating agent.

In addition, the present invention provides an ultra-soft moisture-curable waterproof coating comprising the composition, and particularly, an ultra-soft moisture-curable waterproof coating applied to prevent movement of ions and conduction of electricity by water in a printed circuit board assembly when an electronic device is immersed in water.

In addition, the present invention provides a printed circuit board assembly coated with the above-described ultra-soft moisture-curable waterproof coating agent.

The present invention provides a moisture-curable waterproof coating composition comprising: polydimethylsiloxane containing hydroxyl groups at both terminals; polydimethylsiloxane as a plasticizer; a crosslinking agent; and a catalyst.

In one embodiment of the present invention, the polydimethylsiloxane containing hydroxyl groups at both terminals may be included in an amount of 10 wt% or more and less than 50 wt% based on the total weight of the composition.

In one embodiment of the present invention, the polydimethylsiloxane containing hydroxyl groups at both terminals may have an average molecular weight of 3,000 to 140,000 g/mol.

In one embodiment of the present invention, polydimethylsiloxane as the plasticizer may be included in an amount of more than 30 wt% and less than 90 wt% based on the total weight of the composition.

In one embodiment of the present invention, the polydimethylsiloxane as the plasticizer may have an average molecular weight of 1,000 to 140,000 g/mol.

In one embodiment of the present invention, the crosslinking agent may be an oxime-type or alcohol-type silane coupling agent.

In one embodiment of the present invention, the crosslinking agent may be included in an amount of 1 to 10 wt% based on the total weight of the composition.

In one embodiment of the present invention, the catalyst may be an organotin-based catalyst.

In one embodiment of the present invention, the content of the catalyst may be included in an amount of 0.01 to 1 wt% based on the total weight of the composition.

In one embodiment of the present invention, the cured product of the composition can be deformed, preferably penetrated, by an external force of 20 gf.

In one embodiment of the present invention, the cured product of the composition may have a complex shear modulus of 3 to 20 kPa.

The present invention provides an ultra-soft moisture-curable waterproof coating agent comprising the composition.

The present invention provides a printed circuit board assembly coated with the above-described ultra-soft moisture-curable waterproof coating agent.

The moisture-curable waterproof coating composition of the present invention has an ultra-soft characteristic, unlike existing conformal coating resins, and thus has a characteristic of being easily deformed by a weak external physical force (20 gf), thereby enabling connector connection even after coating on a printed circuit board assembly, and further has excellent waterproofness and fast and stable moisture-curing characteristics. Therefore, if the moisture-curable waterproof coating composition of the present invention is used, the coating can be applied to a connector in advance and used without any restrictions on the assembly of a printed circuit board.

Figure 1 illustrates that when a super-soft moisture-curable waterproof coating agent according to the present invention is coated on a printed circuit board and a semiconductor device is connected, deformation occurs in the coating agent, thereby enabling current conduction between the semiconductor device and the printed circuit board.

The term "moisture curing" in the present invention refers to curing or vulcanization of a curable portion of a material or polymer by a condensation cross-linking reaction of terminal functional groups of the polymer chain caused by water or moisture in the air in the presence of a moisture curing catalyst.

In the present invention, the term "water-resistant coating" is used to mean a conformal coating that enhances water resistance (water resistance).

In the present invention, a "printed circuit board (PCB)" is a component configured such that wiring is integrated so that various elements can be mounted or electrically connected between elements can be achieved. Electronic elements (e.g., electronic chips) are mounted on a printed circuit board to form a printed circuit board assembly, and printed circuit board assemblies of various shapes and functions are being manufactured as technology advances. Examples of these include RAM, motherboards, and LAN cards.

One embodiment of the present invention is a one-component, ultra-soft, moisture-curable composition as a coating agent containing polysiloxane as a main component.

The ultra-soft moisture-curable waterproof coating composition of the present invention comprises: polydimethylsiloxane containing hydroxyl groups at both terminals; polydimethylsiloxane as a plasticizer; a crosslinking agent; and a catalyst.

The moisture-curable waterproof coating composition of the present invention has ultra-soft properties, unlike existing conformal coating resins, so that deformation such as pushing or puncturing easily occurs due to a weak external physical force, for example, 20 gf, after coating and curing, and thus, when connecting a semiconductor device, connection or grounding between a connector and a semiconductor device is possible.

(A) Polydimethylsiloxane containing hydroxyl groups at both terminals

In one embodiment of the present invention, the polydimethylsiloxane containing hydroxyl groups at both terminals may be included in an amount of 10 wt% or more and less than 50 wt% based on the total weight of the composition.

If the content of polydimethylsiloxane containing hydroxyl groups at both terminals is 50 wt% or more, the crosslinking density becomes too high to impart ultra-soft properties, and if it is less than 10 wt%, the degree of crosslinking is insufficient and the plasticizer is eluted, which may cause serious defects in surrounding devices.

In one embodiment of the present invention, the polydimethylsiloxane containing hydroxyl groups at both terminals may have an average molecular weight of 3,000 g/mol to 140,000 g/mol.

When the average molecular weight of the polydimethylsiloxane containing hydroxyl groups at both terminals is less than 3,000 g/mol, the chain length of the polymer participating in polymerization is too short and the degree of crosslinking is insufficient. The dissolution of the plasticizer may be induced and the modulus may increase, and when it exceeds 140,000 g/mol, even if polydimethylsiloxane containing hydroxyl groups at both terminals is contained in an amount of 50 wt% or more of the total composition, ultra-soft characteristics can be exhibited, but the viscosity of the coating solution becomes too high, making it difficult to handle during application and thus difficult to use as a conformal coating agent.

For example, the polydimethylsiloxane having hydroxyl groups at both terminals can have a viscosity of about 300,000 cSt or less, specifically about 200,000 cSt or less, more specifically about 150,000 cSt or less, and most specifically about 100,000 cSt or less, wherein the lower limit of each range is greater than 0, such as 1 cSt or 5 cSt.

(B) Polydimethylsiloxane as a plasticizer

The composition of the present invention includes polydimethylsiloxane as a plasticizer in order to smoothly impart ultra-soft properties. The reason for including polydimethylsiloxane as a plasticizer is to ensure compatibility with other raw materials participating in the curing reaction, but all chemical substances that do not participate in the crosslinking reaction can be used.

If the average molecular weight of the above polydimethylsiloxane is less than 1,000 g/mol, it may have a negative effect on surrounding devices after coating due to the volatile matter of the raw material, and if it exceeds 140,000 g/mol, the viscosity of the coating solution becomes too high, making it difficult to handle during application and the discharge property is not good, making it impossible to use it as a coating agent.

In one embodiment of the present invention, polydimethylsiloxane as the plasticizer may be included in an amount of more than 30 wt% and less than 90 wt% based on the total weight of the composition.

If polydimethylsiloxane as a plasticizer is included in an amount of 30 wt% or less based on the total weight of the composition, the crosslinking density becomes too high and the composition cannot have ultra-soft properties. If it is included in an amount of 90 wt% or more, problems may arise in which the composition cannot function as a coating agent due to dissolution of the plasticizer and a semi-liquid state after curing.

The average molecular weight of polydimethylsiloxane contained as a plasticizer is controlled within a range that provides suitable viscosity to the coating agent. The lower the average molecular weight, the less tacky it is after curing, and a smooth surface condition can be obtained.

(C) Crosslinking agent

In one embodiment of the present invention, the crosslinking agent may be an oxime type, alcohol type, acetic acid type, acetone type silane coupling agent, etc.

Preferably, the crosslinking agent may be one or a mixture of two or more selected from the group consisting of methyltrismethylethylketoximsilane, vinyltrismethylethylketoximsilane, and tetramethylethylketoximsilane, but is not limited thereto and all silane coupling agents may be used.

The crosslinking agent may be included in an amount of 1 to 10 wt% based on the total weight of the composition.

If the content of the crosslinking agent exceeds 10 wt%, a cloudy phenomenon may occur due to a difference in compatibility with existing siloxane-based polymers, and the crosslinking density may become too high, resulting in an excessively high modulus. If it is less than 1 wt%, the crosslinking density may be too low, resulting in a semi-liquid or gel state that cannot maintain its shape, or the plasticizer may be eluted after a long period of time after curing.

(D) Catalyst

The ultra-soft moisture-curable waterproof coating composition of the present invention is cured by a hydrolysis condensation reaction using a catalyst and moisture.

Accordingly, the composition of the present invention comprises a silicone polymer, a plasticizer, a crosslinking agent and a moisture-curing catalyst that initiates moisture curing of the composition in the presence of moisture.

The crosslinking reaction is a condensation reaction, which leads to the product of a crosslinked network through Si-O-Si covalent bonds between water-reactive components.

The moisture-curing catalyst used in the moisture-curing type waterproof coating composition of the present invention includes those known to those skilled in the art as being useful for catalytically promoting and facilitating moisture curing. The catalyst may be a metal or non-metal catalyst. Examples of metal catalysts useful in the present invention include organometallic compounds of tin, titanium, zinc, zirconium, lead, iron, cobalt, antimony, manganese and bismuth. Preferably, an organotin-based catalyst can be used, but is not limited thereto as long as it induces a silicone hydrolysis condensation reaction.

In one embodiment, the moisture cure catalyst useful for promoting the moisture cure of the silicone composition is dibutyltin dilaurate, tin dimethyldineodecanoate, dioctyltin didecylmercaptide, dibutyltin diacetate, dibutyltin dimethoxide, stannous octoate, isobutyltin triceroate, dibutyltin oxide, solubilized dibutyltin oxide, dibutyltin bisdiisooctylphthalate, bis-tripoxysilyl dioctyltin, dibutyltin bis-acetylacetone, silylated dibutyltin dioxide, carbomethoxyphenyltin tris-uberate, isobutyltin triceroate, dimethyltin dibutyrate, dimethyltin dineodecanoate, triethyltin tartarate, dibutyltin dibenzoate, tin. It may be, but is not limited to, tin oleate, tin naphthenate, butyltin tri-2-ethylhexyl hexoate, tin butyrate or dioctyltin didecyl mercaptide.

Preferably, the moisture curing catalyst may be dibutyltin dilaurate.

In one embodiment of the present invention, the catalyst may be included in an amount of 0.01 to 1 wt% based on the total weight of the composition.

The moisture-curable waterproof coating composition of the present invention may have a viscosity of 300 to 500,000 cSt. Preferably, it may be 300 to 100,000 cSt. More preferably, it may be 300 to 50,000 cSt.

The moisture-curable waterproof coating composition of the present invention has a viscosity within the above range, thereby ensuring excellent discharge properties and enabling smooth processability.

The above moisture-curable waterproof coating composition has excellent water resistance and fast and stable moisture-curing characteristics.

According to one embodiment of the present invention, the ultra-soft moisture-curable waterproof coating composition can have a tack-free curing time of 3 to 15 minutes based on a 15 μm application.

The cured product of the composition of the present invention can be deformed even by an external force of 20 to 100 gf. More preferably, deformation should occur by an external force of 20 gf.

The cured product of the composition of the present invention may have a complex shear modulus of 3 to 50 kPa. More preferably, it may be 3 to 20 kPa.

The composition of the present invention, cured to a thickness of 1 mm The complex shear modulus must be 20 kPa or less so that grounding can be achieved between the connector and the semiconductor device even at a very low pressure of 20 gf. If the complex shear modulus is 20 kPa or more, a greater force is required to deform the cured form of the coating agent, making it difficult to achieve grounding between the connector and the semiconductor device, and may even result in poor grounding. In addition, if the complex shear modulus is 3 kPa or less, it is closer to a gel state than a solid state, so there is a high risk of dissolution.

The composite modulus can be controlled by controlling the ratio of hydroxyl groups in the polydimethylsiloxane having hydroxyl groups at both terminals included in the composition of the present invention or controlling the ratio of polydimethylsiloxane as a plasticizer. If the ratio of hydroxyl groups in the polydimethylsiloxane having hydroxyl groups at both terminals is high or the ratio of polydimethylsiloxane as a plasticizer is low, the composite modulus of the cured product becomes high, and therefore, a greater force is required to cause deformation in the cured composition.

In addition, the present invention provides an ultra-soft moisture-curable waterproof coating agent comprising the composition.

In order to impart thixotropic properties to the above-mentioned ultra-soft moisture-curable waterproof coating agent, an inorganic filler may be further included.

In addition, dyes, pigments and fluorescent substances may be included to easily check the application state after coating, and a silane coupling agent capable of inducing intermolecular attraction or chemical bonding with the substrate may be used as an adhesive agent.

In addition, the present invention provides a printed circuit board assembly coated with the ultra-soft moisture-curable waterproof coating agent.

For example, the printed circuit board assembly may include a plurality of electronic components; a printed circuit board on which the plurality of electronic components are mounted; a protective body covering the entire printed circuit board; and a connection unit configured such that one end is exposed to the outside of the protective body so that the printed circuit board can be electrically connected to a sub-board.

The above printed circuit board assembly can be configured such that when a semiconductor device is connected, the connector is connected by an external force of 20 to 100 gf, thereby enabling current to flow between the semiconductor device and the printed circuit board.

Hereinafter, the present invention will be described in more detail through examples and comparative examples. These examples are presented only as examples to more specifically explain the present invention, and it will be obvious to those skilled in the art that the scope of the present invention is not limited by these examples.

<Example 1>

In a reactor, 20 wt% of polydimethylsiloxane (a mixture of average molecular weights of 100,000 g/mol, 45,000 g/mol, and 5,000 g/mol, purchased from Luminex) containing hydroxyl groups at both terminals, 70 wt% of polydimethylsiloxane (a mixture of average molecular weights of 15,000 g/mol and 30,000 g/mol) (purchased from Luminex) as a plasticizer, 4 wt% of a mixture of methyltrismethylethylketoximsilane (purchased from Seogwang Chemical), vinyltrismethylethylketoximsilane (purchased from Seogwang Chemical), and tetramethylethylketoximsilane (purchased from Seogwang Chemical) as a crosslinking agent, 0.1 wt% of dibutyltin dilaurate (purchased from Tokyo Chemical Industry Co., Ltd.) as a catalyst, and 5.9 wt% of other additives. The composition was prepared by adding and stirring.

<Example 2>

A composition was prepared by adding 15 wt% of polydimethylsiloxane (average molecular weight: 120,000 g/mol) having hydroxyl groups at both terminals (purchased from: Luminex) as a reactor, 75 wt% of polydimethylsiloxane (average molecular weight: 1,500 g/mol) (purchased from: Luminex) as a plasticizer, 4 wt% of a mixture of methyltrismethylethylketoximsilane, vinyltrismethylethylketoximsilane, and tetramethylethylketoximsilane (purchased from: Seo Kwang Chemical) as a crosslinking agent, 0.1 wt% of dibutyltin dilaurate (purchased from: Tokyo Chemical Industry Co., Ltd.) as a catalyst, and 5.9 wt% of other additives, and stirring the mixture.

<Example 3>

A composition was prepared by adding 30 wt% of polydimethylsiloxane (average molecular weight: 6,000 g/mol) (purchased from Luminex) having hydroxyl groups at both ends, 60 wt% of polydimethylsiloxane (average molecular weight: 30,000 g/mol) (purchased from Luminex) as a plasticizer, 4 wt% of a mixture of methyltrismethylethylketoximsilane (purchased from Seo Kwang Chemical), vinyltrismethylethylketoximsilane (purchased from Seo Kwang Chemical), and tetramethylethylketoximsilane (purchased from Seo Kwang Chemical) as a crosslinking agent, 0.1 wt% of dibutyltin dilaurate (purchased from Tokyo Chemical Industry Co., Ltd.) as a catalyst, and 5.9 wt% of other additives, and stirring the mixture.

<Comparative Example 1>

A composition was prepared in the same manner as in Example 1, except that polydimethylsiloxane containing hydroxyl groups at both terminals and having an average molecular weight of 2,000 g/mol was used.

<Comparative Example 1-1>

A composition was prepared in the same manner as in Example 1, except that 55 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals and having an average molecular weight of 3,500 g/mol was used, and the content of the plasticizer was 35 wt%.

<Comparative Example 1-2>

A composition was prepared in the same manner as in Example 1, except that 5 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals and having an average molecular weight of 3,500 g/mol was used, and the content of the plasticizer was 85 wt%.

<Comparative Example 2>

A composition was prepared in the same manner as in Example 1, except that polydimethylsiloxane containing hydroxyl groups at both terminals and having an average molecular weight of 150,000 g/mol was used.

<Comparative Example 2-1>

A composition was prepared in the same manner as in Example 1, except that 55 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals and having an average molecular weight of 150,000 g/mol was used, and the content of the plasticizer was 35 wt%.

<Comparative Example 2-2>

A composition was prepared in the same manner as in Example 1, except that 5 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals and having an average molecular weight of 150,000 g/mol was used, and the content of the plasticizer was 85 wt%.

<Comparative Example 3>

A composition was prepared in the same manner as in Example 1, except that polydimethylsiloxane having an average molecular weight of 700 g/mol was used.

<Comparative Example 3-1>

A composition was prepared in the same manner as in Example 1, except that 93 wt% of polydimethylsiloxane having an average molecular weight of 1,250 g/mol and 3 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals were used.

<Comparative Example 3-2>

A composition was prepared in the same manner as in Example 1, except that 25 wt% of polydimethylsiloxane having an average molecular weight of 1,250 g/mol and 65 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals were used.

<Comparative Example 4>

A composition was prepared in the same manner as in Example 1, except that polydimethylsiloxane having an average molecular weight of 150,000 g/mol was used.

<Comparative Example 4-1>

A composition was prepared in the same manner as in Example 1, except that 93 wt% of polydimethylsiloxane having an average molecular weight of 150,000 g/mol and 3 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals were used.

<Comparative Example 4-2>

A composition was prepared in the same manner as in Example 1, except that 25 wt% of polydimethylsiloxane having an average molecular weight of 150,000 g/mol and 65 wt% of polydimethylsiloxane containing hydroxyl groups at both terminals were used.

<Comparative Example 5>

A composition was prepared in the same manner as in Example 1, except that 15 wt% of the crosslinker was used and 59 wt% of polydimethylsiloxane was used as a plasticizer.

<Comparative Example 6>

A composition was prepared in the same manner as in Example 1, except that 0.5 wt% of the crosslinker was used and 73.5 wt% of polydimethylsiloxane was used as a plasticizer.

The compositions of Examples 1 to 3 and Comparative Examples 1 to 6 are summarized in Table 1 below.

(Unit: g/mol, weight%) (A) (B)
(C) (D) Additives Example 1 100,000, 45,000, 5,000 15,000, 30,000 4 0.1 5.9 20 70 Example 2 120,000 1,500 4 0.1 5.9 15 75 Example 3 6,000 30,000 4 0.1 5.9 30 60 Comparative Example 1 2,000 15,000,
30,000 4 0.1 5.9 20 70 Comparative Example 1-1 3,500 15,000,
30,000 4 0.1 5.9 55 35 Comparative Example 1-2 3,500 15,000,
30,000 4 0.1 5.0 5 70 Comparative Example 2 150,000 15,000,
30,000 4 0.1 5.9 20 70 Comparative Example 2-1 139,000 15,000,
30,000 4 0.1 5.9 55 35 Comparative Example 2-2 139,000 15,000,
30,000 4 0.1 5.9 5 85 Comparative Example 3 100,000, 45,000, 5,000 700 4 0.1 5.9 20 70 Comparative Example 3-1 100,000, 45,000, 5,000 1,250 4 0.1 5.9 3 93 Comparative Example 3-2 100,000, 45,000, 5,000 1,250 4 0.1 5.9 65 25 Comparative Example 4 100,000, 45,000, 5,000 150,000 4 0.1 5.9 20 70 Comparative Example 4-1 100,000, 45,000, 5,000 150,000 4 0.1 5.9 3 93 Comparative Example 4-2 100,000, 45,000, 5,000 150,000 4 0.1 5.9 65 25 Comparative Example 5 100,000, 45,000, 5,000 15,000, 30,000 15 0.1 5.9 20 59 Comparative Example 6 100,000, 45,000, 5,000 15,000, 30,000 0.5 0.1 5.9 20 73.5

<Experimental Example 1>: Current Test

The samples of Examples 1 to 3 and Comparative Examples 1 to 6 were cured for 24 hours at a relative temperature of 25°C and a relative humidity of 50% to a thickness of 500 μm, and then a current test (SEMI test) was performed at a pin pressure of 20 gf. The results are shown in Table 2 below.

<Experimental Example 2>: Modulus Measurement

The samples of Examples 1 to 3 and Comparative Examples 1 to 6 were cured to a thickness of 1 mm, and the modulus of the obtained cured products was measured (measuring device: Anton Pasar MCR-702 rheometer) according to the test standard: ISO-6721-10, and the maximum value was confirmed. The results are shown in Table 2 below.

<Experimental Example 3>: Measurement of water resistance

The samples of Examples 1 to 3 and Comparative Examples 1 to 6 were coated and cured at a thickness of 15 μm on a copper-plated printed circuit board at intervals of 0.318 mm, and then a leakage current test (measuring device: DC power supply & Multimeter) was performed for 1 hour while immersed in water to measure water resistance. The results are shown in Table 2 below.

Conductivity Modulus (kPa) Water resistance
(No leakage current) Eruption viscosity
(cSt) Example 1 O 5 O X 2500 Example 2 O 4 O X 550 Example 3 O 12 O X 720 Comparative Example 1 O Liquid X O 600 Comparative Example 1-1 X 39 X O 60 Comparative Example 1-2 O Unable to maintain shape X O 690 Comparative Example 2 O 2.8 O O 3200 Comparative Example 2-1 X 21 O X 14000 Comparative Example 2-2 O 0.8 X O 1500 Comparative Example 3 O 2 X O 240 Comparative Example 3-1 O Liquid X O 16 Comparative Example 3-2 X 37 O X 2100 Comparative Example 4 O 2.7 O O 70000 Comparative Example 4-1 O Unable to maintain shape X O 79000 Comparative Example 4-2 X 41 O X 63000 Comparative Example 5 X 36 O X 2300 Comparative Example 6 O Unable to maintain shape X O 2900

As shown in Table 2 above, the samples of Examples 1 to 3 according to the present invention had low modulus and excellent bonding properties, so they had excellent electrical conductivity and water resistance, and no dissolution occurred.

However, in the case of Comparative Examples 1 to 6, problems occurred in which the modulus was high and the bonding property was low, resulting in poor electrical conductivity or water resistance, or in which the crosslinking density was too low and dissolution occurred.

In addition, in the case of Comparative Example 4 using polydimethylsiloxane having an average molecular weight of 150,000 g/mol, the viscosity of the composition is too high, resulting in poor dischargeability (processability), making it difficult to use as a coating agent.

Claims (16)

Polydimethylsiloxane containing hydroxyl groups at both terminals;
Polydimethylsiloxane as a plasticizer;
Crosslinking agent: and
Containing a catalyst,
The polydimethylsiloxane containing hydroxyl groups at both terminals has an average molecular weight of 3,000 to 140,000 g/mol.
A super-soft moisture-curable waterproof coating composition. In the first paragraph,
A composition wherein the polydimethylsiloxane containing hydroxyl groups at both terminals is contained in an amount of 10 wt% or more and less than 50 wt% based on the total weight of the composition. delete In the first paragraph,
A composition wherein polydimethylsiloxane as the plasticizer is contained in an amount of more than 30 wt% and less than 90 wt% based on the total weight of the composition. In the first paragraph,
A composition wherein the polydimethylsiloxane as the plasticizer has an average molecular weight of 1,000 to 140,000 g/mol. In the first paragraph,
A composition wherein the cross-linking agent is an oxime-type, alcohol-type, acetic acid-type or acetone-type silane coupling agent. In the first paragraph,
A composition wherein the crosslinking agent is contained in an amount of 1 to 10 wt% or less based on the total weight of the composition. In the first paragraph,
A composition wherein the above catalyst is an organotin catalyst. In the first paragraph,
A composition wherein the catalyst is contained in an amount of 0.01 to 1 wt% based on the total weight of the composition. In the first paragraph,
The above composition is a composition having a viscosity of 300 to 50,000 cSt. In the first paragraph,
The cured product of the above composition is a composition that undergoes deformation by an external force of 20 gf. In the first paragraph,
A composition wherein the composite modulus of the cured product of the above composition is 3 to 20 kPa. In the first paragraph,
The above composition is a composition having a tack free time of 3 to 15 minutes based on a 15㎛ application. An ultra-soft moisture-curable waterproof coating comprising a composition according to any one of claims 1 to 2 and claims 4 to 13. A printed circuit board assembly coated with a super-soft moisture-curable waterproof coating agent of Article 14. In Article 15,
The above printed circuit board assembly is a printed circuit board assembly that is deformed by an external force of 20 gf when a semiconductor device is connected, thereby enabling current to flow between the semiconductor device and the printed circuit board.