KR102519043B1 - Dual-curable high-viscosity adhesive composition with improved glass transition temperature - Google Patents

Abstract

The present invention relates to a dual curing type-high viscosity adhesive composition with improved glass transition temperature. More specifically the dual curing type-high viscosity adhesive composition consists of an epoxy resin mixture, a diluent, an anti-foaming agent, a filler material, a photoinitiator, a cationic photoinitiator, a cationic curing agent, a polymerization inhibitor and a thickener. The adhesive composition consisting of the ingredients is cured by an LED light source or heat, and exhibits high viscosity, but has no difference in physical properties between a surface and an inner part of the adhesive. In addition, the adhesive composition does not cause precipitation or separation, exhibits excellent dispersion stability by removing air bubbles due to an antifoaming agent, and exhibits excellent heat resistance due to high glass transition temperature.

Description

Dual-curable high-viscosity adhesive composition with improved glass transition temperature

The present invention relates to a dual-curing high-viscosity adhesive composition having an improved glass transition temperature, and more specifically, curing by an LED light source or heat, showing high viscosity, no difference in physical properties between the surface and the inside of the adhesive, and no precipitation or separation phenomenon. It relates to a dual-curing high-viscosity adhesive composition with improved glass transition temperature, which not only does not occur, but also exhibits excellent dispersion stability due to the removal of air bubbles due to the antifoaming agent and exhibits excellent heat resistance due to a high glass transition temperature.

Adhesives are applied in various industrial fields and are used to connect different parts to each other. Compared to assembly using bolts and nuts or joining using soldering, the process is simple, and it is advantageous in terms of light weight and environmental safety. Its usage is gradually increasing.

When adhesives are applied to electronic products, there are cases where electrical conductivity needs to be imparted in addition to adhesive performance. In the case of electrically conductive adhesives instead of soldering, flake-shaped silver particles are added to epoxy resin that realizes adhesive performance to improve electrical conductivity. The method of giving is mainly used.

In order to impart conductivity to the adhesive in the above process, a large amount of the injected silver particles must be connected or contacted with each other to allow current to pass through.

In addition, there are many cases where electronic products inevitably generate heat during operation, and a technology for releasing the generated heat to the outside is required. Recently, according to the trend of miniaturization of electronic products, the heat generated during operation is effectively diffused and removed. In order to do this, high thermal conductivity is required for adhesives. For example, in the case of adhesives used for attaching semiconductor chips in the manufacture of electronic products, it is preferable to have high thermal conductivity. We are developing adhesives with added metal alloys. However, fillers of inorganic or metal fine particles dispersed in organic polymers are generally recognized to have high interfacial resistance and poor electron and positron movement.

On the other hand, silicone-based and epoxy-based resins are common as conventional adhesives for LED packaging materials, but most of them have low heat dissipation characteristics, resulting in a problem in that product life is not long.

In addition, conventional adhesives for LED packaging materials show differences in physical properties between the surface and the inside of the adhesive, so they do not exhibit uniform conductivity or heat transfer performance, and there is a problem of low dispersion stability due to precipitation or phase powder.

In addition, conventional adhesives have a low glass transition temperature, so adhesive performance can be easily deteriorated due to high heat generated in electronic products, so there is a problem in that application fields are limited.

Korean Patent Registration No. 10-1732965 (2017.04.27.) Korean Patent Publication No. 10-2019-0085349 (2019.07.18.)

The purpose of the present invention is to cure by LED light source or heat, show high viscosity, but there is no difference in physical properties between the surface and inside of the adhesive, and no precipitation or separation occurs. To provide a dual-curing high-viscosity adhesive composition having an improved glass transition temperature and exhibiting excellent heat resistance due to a high glass transition temperature.

An object of the present invention is an epoxy resin mixture, a diluent, an antifoaming agent, a filler, a photoinitiator, a cationic photoinitiator, a cationic curing agent, a polymerization inhibitor and a thickener, characterized in that the glass transition temperature is improved dual curing type high viscosity adhesive composition is achieved by providing.

According to a preferred feature of the present invention, the dual curing type high viscosity adhesive composition having an improved glass transition temperature includes 100 parts by weight of an epoxy resin mixture, 10 to 30 parts by weight of a diluent, 0.2 to 1 part by weight of an antifoaming agent, 0.1 to 40 parts by weight of a filler, and 0.02 parts by weight of a photoinitiator. to 0.2 parts by weight, 1 to 6 parts by weight of a cationic photoinitiator, 1 to 6 parts by weight of a cationic curing agent, 0.01 to 0.2 parts by weight of a polymerization inhibitor, and 0.1 to 40 parts by weight of a thickener.

According to a more preferred feature of the present invention, the epoxy resin mixture is made by mixing an epoxy resin and a liquid type epoxy resin in a ratio of 1:1.

According to a more preferred feature of the present invention, the diluent is made of 100 parts by weight of glycerin (triphosphate) triacrylate and 20 to 50 parts by weight of 2-(2-vinyloxyethoxy)ethyl acrylate.

According to a more preferred feature of the present invention, the photoinitiator is made of bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide.

According to a further preferred feature of the present invention, the filler is made of non-asbestos type talc.

According to a further preferred feature of the present invention, the thickener is made of fumed silica treated with a hydrophobic agent.

According to a more preferred feature of the present invention, the hydrophobic agent is made of one selected from the group consisting of polydimethylsiloxane, hexamethyldisilazane and dimethyldichlorosilane.

The dual-curing high-viscosity adhesive composition with improved glass transition temperature according to the present invention is cured by an LED light source or heat, and while showing high viscosity, there is no difference in physical properties between the surface and the inside of the adhesive, and no precipitation or separation occurs. The antifoaming agent removes air bubbles and exhibits excellent dispersion stability, and exhibits an excellent effect of providing an adhesive composition exhibiting excellent heat resistance due to a high glass transition temperature.

1 is a flow chart showing a manufacturing process of a dual-curing high-viscosity adhesive composition having an improved glass transition temperature according to the present invention.

Hereinafter, a preferred embodiment of the present invention and the physical properties of each component will be described in detail, but this is to be explained in detail so that a person having ordinary knowledge in the art to which the present invention belongs can easily practice the invention, This is not meant to limit the technical spirit and scope of the present invention.

The dual curing high viscosity adhesive composition having improved glass transition temperature according to the present invention is composed of an epoxy resin mixture, a diluent, an antifoaming agent, a filler, a photoinitiator, a cationic photoinitiator, a cationic curing agent, a polymerization inhibitor and a thickener, and 100 parts by weight of the epoxy resin mixture, 10 diluents to 30 parts by weight, 0.2 to 1 part by weight of an antifoaming agent, 0.1 to 40 parts by weight of a filler, 0.02 to 0.2 parts by weight of a photoinitiator, 1 to 6 parts by weight of a cationic photoinitiator, 1 to 6 parts by weight of a cationic curing agent, 0.01 to 0.2 parts by weight of a polymerization inhibitor, and It is preferably composed of 0.1 to 40 parts by weight of the thickener.

The epoxy resin mixture is a main component of the dual-curing high-viscosity adhesive composition having an improved glass transition temperature according to the present invention, and it is preferable that the epoxy resin and the liquid epoxy resin are mixed in a ratio of 1:1.

As the epoxy resin, a bisphenol A, F, or celoxide-based epoxy resin may be used. In addition, Duksan YDF-170 can be used as the liquid type epoxy resin. When a filler having good heat transfer properties is mixed and included inside the matrix of the epoxy resin, the filler is a stable liquid phase inside the matrix of the epoxy resin to restore the original state. By maintaining the position as it is, it serves to suppress the phenomenon that the filler is separated from the inside of the matrix and gradually precipitated even after time elapses after being mixed with the epoxy resin due to the difference in specific gravity.

The diluent contains 10 to 30 parts by weight, and serves to dilute the epoxy resin mixture to lower the viscosity while not significantly reducing the adhesive performance, 100 parts by weight of glycerin (triphosphate) triacrylate and 2-(2 - It is preferably composed of 20 to 50 parts by weight of vinyloxyethoxy) ethyl acrylate.

If the content of the diluent is less than 10 parts by weight, the viscosity of the adhesive is too high, so that additives, thickeners, fillers, etc. cannot be mixed evenly, so that uniform physical properties cannot be exhibited. It is undesirable because the content of the resin mixture is too low, and the physical properties and viscosity of the pressure-sensitive adhesive may be excessively reduced while the above effects are not greatly improved.

The antifoaming agent is contained in an amount of 0.2 to 1 part by weight, and serves to improve dispersibility by suppressing the formation of bubbles in the adhesive prepared through the present invention, and it is preferable to use BYK-1790 of BYK.

If the content of the antifoamer is less than 0.2 parts by weight, the above effect is insignificant, and if the content of the antifoamer exceeds 1 part by weight, the above effect may not be greatly improved and the physical properties of the adhesive may be deteriorated.

The filler is contained in an amount of 0.1 to 40 parts by weight, and physical properties such as heat resistance, dimensional stability, and flexural modulus of the adhesive layer made of the adhesive of the present invention can be improved.

At this time, the filler is preferably made of non-asbestos type talc, and KOCH's KC3000 may be used. When the content of the filler exceeds 40 parts by weight, the effect is not greatly improved, and the present invention This is not preferable because the adhesive force of the adhesive may be excessively lowered.

The photoinitiator is contained in an amount of 0.02 to 0.2 parts by weight, and is preferably composed of bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide {Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide}, the present invention It serves to allow the adhesive manufactured through the curing by irradiation of a light source such as LED.

If the content of the photoinitiator is less than 0.02 parts by weight, the curing of the adhesive proceeds too slowly when irradiated with a light source, and if the content of the photoinitiator exceeds 0.2 parts by weight, the above effects are not greatly improved and the physical properties of the adhesive can be reduced. there is.

The cationic photoinitiator is contained in an amount of 1 to 6 parts by weight, and serves to impart cationic curing reaction performance to the adhesive prepared through the present invention. It shows high cationic curing reactivity at room temperature and does not contain antimony. Preferably, CIBA's Irgacure 290 can be used.

If the content of the cationic photoinitiator is less than 1 part by weight, the cationic curing reaction performance of the adhesive is too low, and if the content of the cationic photoinitiator exceeds 6 parts by weight, the above effect is not greatly improved and the physical properties of the adhesive can be reduced. not desirable because

The cationic curing agent is contained in an amount of 1 to 6 parts by weight, and serves to impart cationic curing performance to thermosetting adhesives such as cationic epoxy, photoresist, packaging, and anisotropic conductive adhesives. It is recommended to use SAN's AID SI-360 desirable.

If the content of the cationic curing agent is less than 1 part by weight, the above effect is insignificant, and if the content of the cationic curing agent exceeds 6 parts by weight, the above effect is not greatly improved and the physical properties of the adhesive may be reduced.

The polymerization inhibitor is contained in an amount of 0.01 to 0.2 parts by weight, and in the adhesive according to the present invention, the polymerization reaction proceeds excessively due to the photoinitiator or the cationic photoinitiator and serves to control the polymerization reaction so that the viscosity is not excessively improved. If the amount is less than 0.01 parts by weight, the above effect is insignificant, and if the content of the polymerization inhibitor exceeds 0.2 parts by weight, the polymerization initiating effect due to the photoinitiator or cationic photoinitiator may be excessively reduced, which is undesirable. At this time, the polymerization inhibitor may be made of AID SI-S of SAN.

The thickener is contained in an amount of 0.1 to 40 parts by weight, and serves to maintain adhesive performance by exhibiting a constant viscosity of the adhesive prepared through the present invention, preferably made of fumed silica treated with a hydrophobic agent.

At this time, the hydrophobic agent is preferably made of one selected from the group consisting of polydimethylsiloxane, hexamethyldisilazane and dimethyldichlorosilane.

In general, fumed silica is a type of synthetic amorphous silica, where synthetic amorphous silica (SAS) is an intentionally manufactured form of silicon dioxide (SiO ₂ ), distinguishing it from naturally occurring amorphous silica, such as diatomaceous earth. As a man-made product, SAS is almost 100% pure amorphous silica, whereas naturally occurring amorphous silica also contains silica in crystalline form. SAS will be manufactured in two forms characterized by two distinct manufacturing practices: (1) wet process silica (including precipitated silica and silica gel) and (2) thermal process silica (including pyrogenic silica, also known as fumed silica). can Thus, fumed silica is SAS formed by a thermal process as opposed to a wet process.

Thermal processes for producing fumed silica use flame pyrolysis. Specifically, fumed silica is produced from flame pyrolysis of silicon tetrachloride or quartz sand vaporized in an electric arc at 3000°C. When fine droplets of amorphous silica are exposed to an electric arc, the droplets fuse into branched, chain-like three-dimensional particles and then agglomerate further into three-dimensional particles. As a result, fumed silica particles have a lower bulk density and higher surface area than wet processed silica particles such as silica gel, and a higher purity than precipitated silica. Fumed silica particles are also non-porous whereas wet processed silica particles are porous. As a result of the thermal process used to make fumed silica particles, fumed silica particles are inherently hydrophilic unless specially treated. To form hydrophobic fumed silica particles, the fumed silica particles (hydrophilic) undergo a chemical post-treatment with a hydrophobic agent. A hydrophobic agent such as an alkoxysilane, silazane or siloxane makes the fumed silica particles hydrophobic by covalently bonding with oxide groups of silicon dioxide molecules on the fumed silica particles. The hydrophobically treated fumed silica used in the present invention is non-porous fumed silica in the form of particles having a hydrophobic agent bonded to the surface of the particle through one or more covalent oxygen bonds.

The dual-curing high-viscosity adhesive composition with improved glass transition temperature composed of the above components is a raw material mixing step (S101) of mixing an epoxy resin mixture, a diluent and an antifoaming agent, and the mixture prepared through the raw material mixing step (S101) is mixed with a planetary mixer The first stirring step (S103) of stirring at low speed, the filler mixing step (S105) of mixing the filler with the mixture stirred through the first stirring step (S103), the mixture prepared through the filler mixing step (S105) A second stirring step (S107) of low-speed stirring with a planetary mixer, an additive mixing step (S109 ), a third stirring step (S111) of removing internal bubbles by stirring the mixture prepared through the additive mixing step (S109) at high speed with a planetary mixer, and bubbles are removed through the third stirring step (S111) Manufacturing consisting of a pulverization and dispersion step (S113) of pulverizing and dispersing the mixture with a 3-roll-mill and a vacuum stirring step (S115) of vacuum stirring the pulverized and dispersed mixture through the pulverization and dispersion step (S113) with a planetary mixer can be produced through the process.

At this time, the first stirring step (S103) and the second stirring step (S107) are preferably composed of a process of low-speed stirring for 30 to 120 seconds at a speed of 500 to 1500 rpm using a planetary mixer. .

In addition, the third stirring step (S111) is a step of stirring the mixture prepared through the additive mixing step (S109) at high speed with a planetary mixer to remove internal bubbles, the additive mixing step (S109) It is preferable that the mixture is introduced into a planetary mixer and stirred at a high speed of 3000 to 10000 rpm for 30 to 120 seconds.

Through the above process, the mixture prepared through the additive mixing step (S109) is evenly mixed, and air bubbles remaining in the mixture are removed, thereby providing an adhesive exhibiting uniform physical properties.

In addition, the grinding and dispersing step (S113) is a step of grinding and dispersing the mixture from which bubbles are removed through the third stirring step (S111) with a 3-roll-mill, and the bubbles are removed through the third stirring step (S111). It is preferable to mill the removed mixture 1 to 3 times with a 3-roll-mill to grind and disperse the mixture. The mixture has improved dispersibility.

At this time, it is preferable that the number of milling of the 3-roll-mill in the grinding and dispersing step (S113) is performed in consideration of the viscosity of the prepared mixture. When the number of milling of the 3-roll-mill exceeds 3 times, the adhesive is dispersed. Although the properties are improved, it is not preferable because the viscosity is too low and the adhesive performance may be deteriorated.

In addition, the vacuum stirring step (S115) is a step of vacuum stirring the mixture pulverized and dispersed through the pulverization and dispersion step (S113) with a planetary mixer, the pulverized and dispersed mixture through the pulverization and dispersion step (S113) is introduced into a planetary mixer and is preferably performed for 30 to 60 seconds at a speed of 500 to 1500 rpm in a vacuum state.

Through the vacuum stirring step (S115) consisting of the above process, the components contained in the mixture pulverized and dispersed through the pulverization and dispersion step (S113) are evenly mixed, but the reaction between each component is suppressed so that there is no difference in physical properties between the surface and the inside, and there is no difference in physical properties and dispersion A high-viscosity adhesive with improved stability can be provided.

Hereinafter, the manufacturing method of the dual-curing high-viscosity adhesive composition having an improved glass transition temperature according to the present invention and the physical properties of the high-viscosity adhesive produced through the manufacturing method will be described with examples.

<Example 1>

Epoxy resin mixture (epoxy resin and liquid type epoxy resin mixed in a ratio of 1: 1) 100 parts by weight, diluent {glycerin (triphosphate) triacrylate 100 parts by weight and 2- (2-vinyloxyethoxy) ethyl acrylate 35 parts by weight} 20 parts by weight and 0.5 parts by weight of an antifoaming agent (BYK-1790 from BYK) were mixed and put into a planetary mixer and stirred at low speed for 75 seconds at a speed of 1000 rpm. 20 parts by weight of cotton-type talc, KC3000) was mixed, the mixture mixed with the filler was put into a planetary mixer and stirred at low speed for 75 seconds at a speed of 1000 rpm, compared to 100 parts by weight of the epoxy resin contained in the low-speed stirred mixture Photoinitiator [bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide {Bis (2,4,6-trimethylbenzoyl) -phenylphosphineoxide)] 0.1 parts by weight, cationic photoinitiator (Irgacure 290) 3.5 parts by weight, cationic curing agent (AID SI-360) 3.5 parts by weight, polymerization inhibitor (AID SI-S) 0.1 parts by weight and thickener (fumed silica treated with polydimethylsiloxane) 20 parts by weight were mixed and put into a planetary mixer at a speed of 7500 rpm Bubbles were removed by high-speed stirring for 75 seconds, and the mixture from which bubbles were removed by high-speed stirring was milled twice with a 3-ROLL-MILL to pulverize and disperse the mixture, and pulverize and disperse the mixture. The mixture was put into a planetary mixer and vacuum stirred at a speed of 1000 rpm for 45 seconds in a vacuum state to prepare a high-viscosity adhesive having improved dispersion stability.

<Comparative Example 1>

DELO-DUALBOND LT3480.

The physical properties of the adhesives of Example 1 and Comparative Example 1 were measured and are shown in Table 1 below.

{However, for the properties of the adhesive, a method of measuring the glass transition temperature (Tg) and shrinkage before and after the glass transition temperature was used.}

<Table 1>

As shown in Table 1, it can be seen that the adhesive prepared through the present invention has excellent heat resistance due to its high glass transition temperature and excellent adhesive strength due to its excellent shrinkage performance.

Therefore, the dual-curing high-viscosity adhesive composition with improved glass transition temperature according to the present invention is cured by an LED light source or heat, and while showing high viscosity, there is no difference in physical properties between the surface and the inside of the adhesive, and no precipitation or separation occurs. In addition, an adhesive composition exhibiting excellent dispersion stability due to the removal of air bubbles due to the antifoaming agent and excellent heat resistance due to a high glass transition temperature is provided.

S101; Raw material mixing step
S103; 1st stirring step
S105; Filler mixing step
S107; 2nd stirring step
S109; Additive mixing step
S111; 3rd stirring step
S113; Grinding and dispersing step
S115; vacuum agitation step

Claims (8)

100 parts by weight of epoxy resin mixture, 10 to 30 parts by weight of diluent, 0.2 to 1 part by weight of antifoaming agent, 0.1 to 40 parts by weight of filler, 0.02 to 0.2 parts by weight of photoinitiator, 1 to 6 parts by weight of cationic photoinitiator, 1 to 6 parts by weight of cationic curing agent , 0.01 to 0.2 parts by weight of polymerization inhibitor and 0.1 to 40 parts by weight of thickener,
The epoxy resin mixture is made by mixing an epoxy resin and a liquid epoxy resin in a ratio of 1: 1,
The diluent is a dual curing type high viscosity adhesive composition with improved glass transition temperature, characterized in that consisting of 100 parts by weight of glycerin (triphosphate) triacrylate and 20 to 50 parts by weight of 2- (2-vinyloxyethoxy) ethyl acrylate.
delete delete delete The method of claim 1,
The photoinitiator is a dual-curing high-viscosity adhesive composition with improved glass transition temperature, characterized in that consisting of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide.
The method of claim 1,
The filler is a dual-curing high-viscosity adhesive composition with improved glass transition temperature, characterized in that consisting of non-asbestos type talc.
The method of claim 1,
The thickener is a dual-curing high-viscosity adhesive composition with improved glass transition temperature, characterized in that consisting of fumed silica treated with a hydrophobic agent.
The method of claim 7,
The hydrophobic agent is polydimethylsiloxane, hexamethyldisilazane and dimethyldichlorosilane, characterized in that consisting of one selected from the group consisting of improved glass transition temperature dual curing high viscosity adhesive composition.

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