KR20230144251A - Photocurable composition and heat-conducting urethane acrylic elastomer prepared therefrom - Google Patents

Abstract

The present invention provides a photocurable composition containing acrylic oligomers, metallic particles, and carbon-based particles, and an acrylic elastomer manufactured therefrom. The photocurable composition can solve the dimensional stability and processability problems of conventional thermosetting polymer-based elastomers. In addition, the acrylic elastomer prepared therefrom can have excellent thermal conductivity.

Description

Photocurable composition and heat-conducting urethane acrylic elastomer prepared therefrom}

The present invention relates to a photocurable composition containing metallic particles and carbon-based particles and an acrylic elastomer manufactured by curing the same.

Currently, in cutting-edge industrial fields, the use of polymer-based elastomers is increasing due to its excellent heat resistance, mechanical properties, and processability. In particular, polymer-based elastomers with excellent ductility and elasticity are used in the miniaturization of electronic devices and robotics fields. It is expected to increase further.

However, in the electrical/electronic field, polymer-based elastomers have low thermal conductivity and cannot sufficiently dissipate heat generated in electronic devices, which may cause problems such as damage or functional deterioration of electronic devices in the future.

In order to solve the thermal conductivity problem of the polymer-based elastomer, the heat resistance of the conventional polymer-based elastomer was increased by adding metallic particles and carbon-based particles, but this method inevitably faces trade-offs such as reduced processability and increased modulus. In addition, conventional polymer-based elastomers have problems with cost volume, process speed, dimensional stability, and adhesion to substrates due to the use of heat-cured or solvent-based elastomers, and the adhesion problem significantly increases thermal conductivity. Couldn't do it.

Therefore, in order to solve the problems of conventional polymer-based elastomers, there is a need for a photocurable polymer-based elastomer with excellent moldability and dimensional stability, and furthermore, a new photocurable polymer that maintains excellent thermal conductivity, self-adhesion, and the physical properties of polymer elastomers. There is a need for a base elastic material.

Korean Patent Publication No. 10-2021-0146614 A Korean Patent Publication No. 10-2020-0073795 A

The purpose of the present invention is to provide an acrylic oligomer with acrylate functional groups introduced at both ends and a photocurable composition containing the same in order to improve the problems of dimensional stability, processability and processability of conventional thermosetting polymer-based elastomers.

The purpose of the present invention is to provide a photocurable composition that simultaneously realizes excellent thermal conductivity and elongation rate and an acrylic elastomer manufactured therefrom in order to improve the problem of reduced elongation caused by the addition of a thermally conductive material in a conventional polymer-based elastomer. .

The present invention is a photocurable composition comprising an acrylic dispersion solution, metal particles, and carbon particles,

The acrylic dispersion solution provides a photocurable composition comprising an acrylic oligomer represented by the following formula (1), a functional monomer, and a photocatalyst.

[Formula 1]

(In Formula 1 above,

A ₁ is C1-C12 straight or branched chain alkylene,

A ₂ and A ₃ are independently C1-C6 straight or branched chain alkylene,

Ar ₁ and Ar ₂ are alkylene containing one or two or more selected from C6-C20 arylene, C6-C20 cycloalkylene, and C3-C20 heteroarylene,

R ₁ and R ₂ are independently hydrogen or C1-C6 straight or branched chain alkyl,

n is an integer from 1 to 20,

m is an integer from 10 to 40.)

According to one embodiment, in Formula 1 above,

A ₁ is C1-C6 straight or branched chain alkylene,

A ₂ and A ₃ are independently C1-C4 straight chain alkylene,

Ar ₁ and Ar ₂ are independently alkylene containing C6-C20 aryl or C6-C20 cycloachilene,

R ₁ and R ₂ are independently hydrogen or C1-C6 straight or branched chain alkyl,

n is an integer from 1 to 10,

m may be an integer of 30 to 40.

In Formula 1 above according to one embodiment.

Ar ₁ and Ar ₂ are , , , , , or It can be.

The acrylic oligomer according to one embodiment may be represented by the following formula (2).

[Formula 2]

(In Formula 2 above,

m is an integer from 30 to 40,

n is an integer from 1 to 10.)

According to one embodiment, the acrylic dispersion solution may have a weight ratio of acrylic oligomer and functional monomer of 1:1 to 1:4.

According to one embodiment, the acrylic dispersion solution may contain 0.01 to 0.1% by weight of a photocatalyst.

According to one embodiment, the acrylic dispersion solution may further include 0.1 to 10% by weight of a crosslinking agent.

According to one embodiment, the photocurable composition may contain 1 to 50% by volume of a metal compound based on the total volume of the acrylic dispersion solution.

According to one embodiment, the metallic particles may be one or two or more selected from aluminum, zinc, silicon, tin, boron, antimony, barium, manganese, titanium, calcium, magnesium, vanidium, copper, iron, and oxides thereof. there is.

According to one embodiment, the photocurable composition may contain 0.01 to 0.2% by volume of carbon-based particles, based on the total volume of the acrylic dispersion solution.

According to one embodiment, the carbon-based particles may include one or two or more selected from single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphite, carbon black, carbon fiber, and fullerene.

The present invention provides an acrylic elastomer manufactured by curing the above-described photocurable composition.

According to one embodiment, the acrylic elastomer may have a thermal conductivity measured by ASTM E1461 of 0.3 W/m·k or more.

According to one embodiment, the acrylic elastomer may have a curing depth of 1 mm or more when the photocurable composition is cured by irradiating an LED with a wavelength of 455 nm for 5 minutes.

The present invention provides a molded article manufactured including the above-described acrylic elastomer.

According to one implementation, the molded article may be one or two or more selected from the group of patterning film, soft robotics material, circuit board material, and adhesive layer.

The photocurable composition according to the present invention contains an acrylic oligomer and a photocatalyst with a specific structure and can be photocured rather than thermally cured, thereby providing excellent workability, dimensional stability, and patterning.

The acrylic oligomer having a specific structure according to the present invention has a long chain structure containing a urethane bond, and thus can significantly increase the elongation and self-adhesion of the acrylic elastomer prepared therefrom when applied to a photocurable composition.

The photocurable composition according to the present invention can have excellent thermal conductivity by containing aluminum and carbon nanotubes (MWCNT).

Therefore, the photocurable composition of the present invention can be used in various fields, such as photocurable adhesives, pressure-sensitive adhesives, and photocurable 3D printing materials, and can be particularly useful in electronic component materials and soft robotics materials that require excellent thermal conductivity. .

Figure 1 is a graph showing the curing depth (a) according to the aluminum content and the curing depth (b) according to the MWCNT content in Comparative Example 1.
Figure 2 is a graph measuring the tensile properties of Examples 1 to 6 and Comparative Examples 1 to 6.
Figure 3 is a graph measuring the thermal conductivity of Examples 1 to 6 and Comparative Examples 1 to 6.
Figure 4 is a graph measuring the self-adhesion of Examples 7 to 12 and Comparative Example 11.
Figure 5 shows the measured patterning of Example 13.

Hereinafter, the photocurable composition according to the present invention and the acrylic elastomer manufactured therefrom will be described in detail. At this time, if there is no other definition in the technical and scientific terms used, they 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.

As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly dictates otherwise.

In addition, the numerical range used in this specification includes the lower limit and upper limit and all values within the range, increments logically derived from the shape and width of the defined range, all double-defined values, and the upper limit of the numerical range defined in different forms. and all possible combinations of the lower bounds. Unless otherwise specified in the specification of the present invention, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

The term “comprises” in this specification is an open description with the same meaning as expressions such as “comprises,” “contains,” “has,” or “characterized by” elements that are not additionally listed; Does not exclude materials or processes.

As used herein, the term “CA-CB” means “carbon number A or more and B or less.”

In this specification, the term capping agent may refer to a compound that caps by reacting with an isocyanate group.

Conventional polymer-based elastomers that impart thermal conductivity are thermoset or melt-type, and have problems such as production cost, process speed, dimensional stability, and adhesion to substrates. Processability is reduced due to particles added to impart thermal conductivity. and there were problems such as an increase in modulus.

As a result of intensifying research to overcome this problem, the present inventors developed an acrylic oligomer with an acrylate end and a photocurable composition containing the same, and the acrylic elastomer manufactured therefrom can have excellent elongation and thermal conductivity at the same time. It has excellent self-adhesion and can be easily patterned, so it can be used for photocuring adhesives, pressure-sensitive adhesives, and photocuring 3D printing materials. In particular, it has been found to be used as electronic component materials and soft robotics materials that require excellent thermal conductivity. And the invention was completed.

Hereinafter, the present invention will be described in detail.

The photocurable composition according to the present invention is intended to produce a polymer-based elastomer by photocuring it differently from the heat-cured one in order to produce a conventional thermally conductive polymer-based elastomer. In particular, the acrylic elastomer manufactured from the photocurable composition is It has technical significance in that it can have excellent thermal conductivity and elongation at the same time.

The present invention is a photocurable composition comprising an acrylic dispersion solution, metal particles, and carbon particles,

The acrylic dispersion solution provides a photocurable composition containing an acrylic oligomer, a functional monomer, and a photocatalyst represented by the following formula (1).

[Formula 1]

(In Formula 1 above,

A ₁ is C1-C12 straight or branched chain alkylene,

A ₂ and A ₃ are independently C1-C6 straight or branched chain alkylene,

Ar ₁ and Ar ₂ are alkylene containing one or two or more selected from C6-C20 arylene, C6-C20 cycloalkylene, and C3-C20 heteroarylene,

R ₁ and R ₂ are independently hydrogen or C1-C6 straight or branched chain alkyl,

n is an integer from 1 to 20,

m is an integer from 10 to 40.)

According to one embodiment, in Formula 1,

A ₁ is C1-C6 straight or branched chain alkylene,

A ₂ and A ₃ are independently C1-C4 straight chain alkylene,

Ar ₁ and Ar ₂ are independently alkylene containing C6-C20 aryl or C6-C20 cycloachilene,

R ₁ and R ₂ are independently hydrogen or C1-C6 straight or branched chain alkyl,

n is an integer from 1 to 10,

m may be an integer of 30 to 40.

According to another implementation, in Formula 1, Ar ₁ and Ar ₂ are , , , , , or It can be.

The photocurable composition containing the urethane oligomer containing Ar ₁ and Ar ₂ of the above structure may have a low viscosity, and the acrylic elastomer prepared therefrom can further increase the cured density and have excellent mechanical strength and heat resistance. In addition, it may be preferred because it can further improve the heat distortion temperature and maintain dimensional stability in a high temperature environment.

The acrylic oligomer according to one embodiment may be represented by the following formula (2).

[Formula 2]

(In Formula 2 above,

m is an integer from 30 to 40,

n is an integer from 1 to 10.)

Hereinafter, the method for producing the acrylic oligomer will be described in detail.

The acrylic oligomer is prepared by reacting a polyol and a diisocyanate compound to produce a polyurethane represented by the following formula (3); and

Preparing an acrylic oligomer represented by Formula 1 by reacting the polyurethane and a capping agent;

It may include.

[Formula 3]

(In Formula 3 above,

A ₁ is C1-C12 straight or branched chain alkylene,

Ar ₁ and Ar ₂ are alkylene containing one or two or more selected from C6-C20 arylene, C6-C20 cycloalkylene, and C3-C20 heteroarylene,

n is an integer from 1 to 20,

m is an integer from 10 to 40.)

The polyol may be an aromatic polyol, an alicyclic polyol, or an aliphatic polyol. However, in order for the prepared acrylic oligomer to have excellent flexibility, an aliphatic polyol may be preferable, and more preferably an aliphatic polyol containing two or more hydroxy groups. You can.

Specifically, the aliphatic polyol may be an alkylene glycol-based polyglycol, for example, and in order to have excellent dispersion of the photocurable composition according to the polyurethane reaction rate and oxygen content of the acrylic oligomer, C1-C12 alkylene glycol is polymerized. It may be preferable to use polyalkylene glycol, and more preferably, the polyalkylene glycol has a weight average weight of 500 to 5,000 g/mol, specifically 1,000 to 3,000 g/mol, so that it can have better flexibility. It may be preferred.

The diisocyanate compound is an aliphatic type. One or two or more selected from the cycloaliphatic, aromatic, and heteroaromatic groups may be used, but as described above, the low viscosity of the photocurable composition containing the prepared acrylic oligomer and the excellent heat resistance and mechanical properties of the acrylic elastomer prepared therefrom In terms of strength, it may be preferable to use an aromatic diisocyanate compound.

The aromatic diisocyanate-based compounds include, for example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, and 4,4'-diisocyanate. Phenylmethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3 '-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4',4"-triphenylmethane triisocyanate, m-isocyanatophenylsulfonylisocyanate and p -It may be isocyanatophenylsulfonyl isocyanate, etc.

The acrylic oligomer may have an acrylate functional group at the end by reacting the polyurethane represented by Formula 3 with a capping agent.

The capping agent can be used as long as the acrylic oligomer contains a carbon double bond vinyl group (*-CH=CH ₂ ) and a functional group that reacts with an isocyanate group in order to provide a radical reaction, and the functional group is, for example, a hydroxy group ( *-OH), thiol group (*-SH), or amine group (*-NH) may be a compound, but the photocurable composition containing acrylic oligomer has excellent dispersion and the excellent mechanical strength of the acrylic elastomer manufactured therefrom. In order to have , compounds containing hydroxy may be more preferred.

Specifically, for photocuring reactivity, the vinyl group may preferably have an acrylic group, and the functional group may preferably have a hydroxy group because it may have better reactivity.

More specifically, the capping group may be an aliphatic capping group, an aromatic capping group, or an alicyclic capping group. However, in order to have excellent curing and reactivity of the photocurable composition containing the prepared acrylic oligomer and better elasticity of the acrylic elastomer prepared therefrom, the capping group may be an aliphatic capping group, an aromatic capping group, or an alicyclic capping group. A capping group may be preferred, and for example, it may be hydroxyalkylene (C1-C6) (meth)acrylate.

Hereinafter, the acrylic dispersion solution of the photocurable composition of the present invention will be described.

According to one embodiment, the acrylic dispersion solution may have a weight ratio of acrylic oligomer and functional monomer of 1:1 to 1:4.

The functional monomer can control the viscosity reduction, curing acceleration, and dispersibility of the photocurable composition, and can control the impact resistance, hardness, flexibility, heat resistance, cohesion, and adhesion of the acrylic elastomer manufactured therefrom, specifically. It may include a diluting monomer, an adhesion-promoting monomer, and an initiation-promoting monomer.

The acrylic liquid solution may contain 10 to 40% by weight of diluted monomer, and more specifically, 15 to 35% by weight.

A photoinitiator composition containing diluted monomers in the above range can provide a viscosity with good workability, and more specifically, can shorten the mixing process time after adding metal particles and carbon particles and have excellent dispersion. It may be preferred.

Specifically, the diluting monomers include, for example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isodecyl (meth)acrylate, 2-( 2-Ethoxyethoxy)ethyl (meth)acrylate, stearyl (meth)acrylate, lauryl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, isobornyl (meth)acrylate, It may be one or a combination of two or more selected from the group consisting of tridecyl (meth)acrylate, polycaprolactone (meth)acrylate, etc., more preferably isobornyl (meth)acrylate, tetrahydrofurfuryl ( It may be meth)acrylate and mixtures thereof.

The photocurable composition containing the isobornyl (meth)acrylate can not only lower the viscosity, but also increase the cohesion, and provide high heat resistance by controlling the polymer glass transition temperature, so that the acrylic elastomer manufactured therefrom It may be preferred because it has excellent mechanical strength and can have excellent elasticity even at room and low temperatures.

The acrylic dispersion solution may not contain an adhesion-promoting monomer or may contain less than 20% by weight, more specifically, 5 to 15% by weight.

A photocurable composition containing an adhesion-promoting monomer in the above range can not only provide a viscosity with good workability, but an acrylic elastomer prepared therefrom can have excellent self-adhesion, so it can be preferred.

Specifically, the adhesion promoting monomer may be hydroxyalkyl (C1-C12) (meth)acrylate, for example, AA (Acrylic acid), HEA (2-hydroxyethyl acrylate), and HBA (4-Hydroxybutyl acrylate). , this is not limited as long as it does not impair the physical properties of the photocurable composition containing it and the acrylic elastomer manufactured therefrom.

The acrylic dispersion solution may contain 10 to 40% by weight of initiation accelerator monomer, and more specifically, 10 to 25% by weight.

A photocurable composition containing an initiation accelerator monomer in the above range may be preferred because not only can no co-initiator be added, but the photocatalyst content can be significantly reduced and the photocuring time can be shortened.

Specifically, the curing accelerator monomer may be N-Vinyl-Pyrrolidone (NVP), N-Vinyl-caprolactam (NVC), or mixtures thereof.

According to one implementation, the dispersion solution may contain 0.01 to 0.1% by weight of the photocatalyst, and specifically may contain 0.01 to 0.05% by weight.

The photocatalyst may be one or more selected from 4DP-IPN, 4Cz-IPN, eosin Y, and camphorquinone described in Korean Patent Publication No. 10-2021-0146614 A.

Since the photocatalyst is not consumed during the curing process of the photocurable composition, a smaller amount can be used than using a photoinitiator, and the content of impurities can be small, so that the acrylic elastomer manufactured therefrom will have superior mechanical strength. It can be preferred.

The acrylic dispersion solution according to one embodiment may further include 0 to 10% by weight of a crosslinking agent, and specifically, may further include 0.5 to 5% by weight.

Acrylic elastomers manufactured with a photocurable composition containing a cross-linking agent at the above content can have excellent elongation and modulus at the same time by increasing the cross-linking content, and can furthermore be preferred because the physical properties can be adjusted by adjusting the cross-linking agent content. there is.

The crosslinking agent may be an aliphatic diacrylate-based compound, and specifically may be polyalkylene (C1-C12) glycol diacrylate, and more specifically, polyethylene glycol di(meth) having a weight average molecular weight of 300 to 1,000 g/mol. ) It may be acrylate.

The photocurable composition according to one embodiment may contain 1 to 50% by volume of a metal compound, specifically 10 to 40% by volume, based on the total volume of the acrylic dispersion solution.

A photocurable composition containing a metal-based compound within the above range may have excellent thermal conductivity and may be preferred because pinhole defects may not occur. A photocurable composition containing a content exceeding the above range may cause the metal-based compound to emit light when irradiated with light. By reflecting, the photocuring depth can be reduced and the elongation rate can be significantly reduced, which can be more preferable.

A photocurable composition containing a metal-based compound within the above range may have excellent thermal conductivity and may be preferred because pinhole defects may not occur. A photocurable composition containing a content exceeding the above range may cause the metal-based compound to emit light when irradiated with light. By reflecting, the photocuring depth can be reduced and the elongation rate can be significantly reduced, which can be more preferable.

The metallic particles according to one embodiment may be one or two or more selected from zinc, silicon, tin, boron, antimony, barium, manganese, titanium, calcium, magnesium, vanidium, copper, iron, and oxides thereof, and may be specifically It may be aluminum, which does not oxidize and has excellent thermal conductivity.

The metal crab particles may preferably be spherical in order to solve the dispersibility and pinhole problems of the photocurable composition containing them, and an average diameter of 1 to 10 ㎛ is preferred because of better dispersibility and may not cause pinhole problems. It can be.

According to one embodiment, the photocurable composition may contain 0.01 to 0.2% by volume of carbon-based particles, specifically 0.01 to 0.1% by volume, based on the total volume of the acrylic dispersion solution.

A photocurable composition containing carbon-based particles within the above range may have better thermal conductivity by distributing carbon-based particles between dispersed metal particles, and a photocurable composition containing carbon-based particles exceeding the above range may have carbon-based particles in the light. It may be more preferable to include carbon-based particles in the above content because the curing depth of the acrylic elastomer manufactured therefrom is lowered.

The carbon-based particles according to one embodiment may include one or two or more selected from single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphite, carbon black, carbon fiber, and fullerene, and more preferably Can be single-walled carbon nanotubes, multi-walled carbon nanotubes, and mixtures thereof.

Since the single/multi-walled carbon nanotubes have excellent thermal conductivity in different transverse directions, an acrylic elastomer manufactured including them can have better thermal conductivity as the carbon nanotubes are well connected between metallic particles.

Hereinafter, the acrylic elastomer of the present invention will be described.

The present invention provides an acrylic elastomer manufactured by curing the above-described photocurable composition.

Specifically, the acrylic elastomer is photocured by irradiating the photocurable composition with ultraviolet rays, infrared rays, or visible light. More specifically, it may be visible light, more specifically visible light with a wavelength of 200 to 500 λ, but the photocurable composition may be photocured by irradiating ultraviolet rays, infrared rays, or visible light. If it is something that can be converted, there is no limit to it.

According to one embodiment, the acrylic elastomer may have a curing depth of 1 mm or more, specifically 2 to 6 mm, when the photocurable composition is cured by irradiating an LED with a wavelength of 455 nm for 5 minutes.

The thermal conductivity measured by ASTM E 1461 according to one implementation may be 0.3 W/m·k or more, and specifically, may be 0.3 to 0.6 or less.

The curing depth and thermal conductivity of the acrylic elastomer increase as the number of metallic particles and carbon-based particles increases, but the photocuring depth may decrease, thereby facing a technical trade-off, and the above-mentioned metallic particles and carbon-based particles It may be desirable to include, and it may be more desirable to adjust their content appropriately.

The present invention provides a molded article manufactured including the acrylic elastomer.

Unlike conventional thermally conductive polymer-based elastomers, the acrylic elastomer can be photocured, so it can be used in a wider range of fields and has excellent processability and productivity.

The molded article according to one embodiment may be one or two or more selected from the group of patterning film, soft robotics material, circuit board material, and adhesive layer.

Since the acrylic elastomer is manufactured by photocuring, it can be patterned more easily using a masking film, so it can be manufactured into more complex shapes and can also be used as a 3D printing material.

In addition, the acrylic elastomer has excellent flexibility and thermal conductivity, so it can be used in the field of soft robotics. It also has excellent self-adhesion, so it can have better thermal conductivity and can easily dissipate heat generated in electronic circuits. It can be used as a photocurable adhesive.

The photocurable composition according to the present invention and the acrylic elastomer manufactured therefrom will be described in more detail through examples below. However, the following examples are only a reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms. Additionally, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. Additionally, the terms used in the description in the present invention are only intended to effectively describe specific embodiments and are not intended to limit the present invention.

[Preparation Example 1] Preparation of acrylic oligomer

167 g of isobutylacrylate (IBOA) was added to a 50 ml round bottom flask equipped with a thermometer and a condenser, stirred for 10 minutes, and purged with nitrogen. Afterwards, 353 g of polypropylene glycol (weight average molecular weight: 2,000 g/mol), 36.5 g of 1,3-bis(isocyanatomethyl)benzene, and 0.39 g of butyltin dilaurate were sequentially added to the flask, and the temperature was raised to 60°C. The reaction was conducted for 8 hours to synthesize formula a.

Afterwards, 49 g of 2-Hydroxyethyl Acrylate was added to the flask in which a was synthesized and reacted at 60°C for 8 hours. After the reaction solution was cooled to room temperature, it was dried in a vacuum oven to produce the acrylic oligomer of the formula above. Obtained.

[measurement method]

1. Cure depth evaluation

The photocurable composition was placed in a vial (20 mL Disposable Scintillation vials, LK Lab Korea), and the bottom of the vial was irradiated with a blue LED (λ: 455 nm, intensity: 57 mW/cm ² ) for 5 minutes and cured, and acetone was added into the vial. was poured and the uncured portion was removed.

Afterwards, the cured part inside the vial was taken out, the edges were trimmed, and the thickness was measured.

2. Tensile property evaluation

The photocurable composition was coated between A4 size release papers to a thickness of 100 ㎛ and cured by irradiating with a blue LED (λ: 455 nm, intensity: 15 mW/cm ² ) for 15 minutes, and laminated in a total of 5 layers in the same manner as above. A 0.5 mm thick film was prepared.

The manufactured film was processed into a specimen according to ASTM D 638 standard and measured using a Universal testing machine (AMETEK, LS1).

3. Thermal conductivity measurement

Using an electronic densimeter (Alfa Mirage, MD-300S), the specific gravity of the sample prepared with the photocurable composition was measured according to ASTM D792, and the value was converted to density.

In addition, differential scanning calorimetry (TA, DSC 25) was used to measure the specific heat of samples prepared with photocurable compositions in accordance with KS M ISO 11357-4.

In addition, thermal diffusivity measurements (NETZSCH, LFA 447) were used to measure the thermal diffusivity of samples prepared with photocurable compositions according to ASTM E1461.

Afterwards, the measured density, specific heat, and thermal diffusivity were calculated using Equation 1 below to obtain the thermal conductivity of the sample.

[Equation 1]

Thermal conductivity (W/m·k) = Density (kg/m ³ ) × Specific heat (J/kg·k) × Thermal diffusion rate (mm ² /s)

Changes in physical properties depending on aluminum and MWCNT content

[Examples 1 to 6 and Comparative Examples 1 to 10]

A dispersion solution was prepared by mixing acrylic oligomer (46.20 wt%), N-Vinylpyrrolidone (NVP, 33.00 wt%), Isobornyl acrylate (IBOA, 19.80 wt%), and Poly(ethylene glycol)diacrylate (PEGDA, 1.00 wt%). , To the dispersion solution, aluminum (Denka, DAW-05) and MWCNT (Applied Carbon nano Technology, A-Tube-AM97) were added in the volume % shown in Table 1 below and mixed with a paste mixer (ARE-310, Thinky). ) was used to prepare a photocurable composition by stirring at room temperature for 6 minutes.

Afterwards, the prepared photocurable composition was measured using the following measurement method and is shown in Figures 1, 2, 3, and Table 1.

Al
(volume%) MWCNTs
(volume%) cure depth
(mm) Tensile properties thermal conductivity
(W/m·k) Young's modulus
(MPa) Elongation at break
(mm/mm) Example 1 10 0.05 3.15 0.23 2.88 0.16 Example 2 10 0.1 2.01 0.24 2.70 0.18 Example 3 30 0.05 1.03 0.62 2.39 0.38 Example 4 30 0.1 0.98 0.74 2.47 0.45 Example 5 50 0.05 1.05 2.67 0.90 0.82 Example 6 50 0.1 0.94 2.86 0.76 0.80 Comparative Example 1 0 0 4.98 0.14 2.46 0.12 Comparative Example 2 One 0 3.59 0.18 3.27 0.10 Comparative Example 3 10 0 1.76 0.20 3.19 0.18 Comparative Example 4 20 0 1.36 0.57 3.11 0.21 Comparative Example 5 30 0 1.21 0.82 3.08 0.26 Comparative Example 6 50 0 1.16 8.44 0.55 0.81 Comparative Example 7 0 0.05 3.20 0.13 2.63 0.09 Comparative Example 8 0 0.1 2.08 0.13 2.47 0.11 Comparative Example 9 0 0.2 0.13 0.14 2.51 0.15 Comparative Example 10 0 0.5 0.05 0.13 2.52 0.19

Checking the curing depth in Table 1 above, it was confirmed that the curing depth decreases as the aluminum and MWCNT content increases, which is a phenomenon caused by light reflection and light diffraction of aluminum and light absorption of MWCNT. In particular, as the MWCNT content increases, the curing depth decreases. It was confirmed that the curing depth was significantly reduced.

In Table 1 above, when checking the tensile properties, the Young's modulus does not significantly increase up to 30 vol% of aluminum, but it increases significantly in Examples 5, 6, and Comparative Example 6 containing 50 vol% of aluminum, resulting in a decrease in elongation at break. It was confirmed that this was the case.

Checking the thermal conductivity in Table 1, it was confirmed that the thermal conductivity increased as the aluminum and MWCNT content increased, and Examples 3 and 4, which contained 30% by volume of aluminum, showed the greatest difference in thermal conductivity.

Therefore, the physical property behavior of acrylic elastomers according to the aluminum and MWCNT content means that as the aluminum and MWCNT content increases, the thermal conductivity value increases, but the curing depth decreases and the curing time becomes longer. In the cured product containing 30% by volume of aluminum, the curing time becomes longer. Thermal conductivity significantly increases depending on the MWCNT content.

In addition, in terms of the tensile properties of the acrylic elastomer, as the aluminum content increases, the Young's modulus increases, thereby reducing the elongation at break. In particular, the Young's modulus of the acrylic elastomer containing more than 30% by volume of aluminum significantly increases.

Therefore, this suggests that it is possible to secure the target thermal conductivity, tensile modulus, and hardening behavior by controlling the aluminum and MWCNT contents.

Changes in physical properties depending on the composition of the dispersion solution

[measurement method]

4. 90 ^o peel measurement

Samples were prepared and measured according to ASTM D3330. The photocurable composition was coated to a thickness of 50 ㎛ between the PET substrate and the release paper and cured by irradiating a blue LED (λ: 455 nm, intensity: 15 mW/cm ² ) for 15 minutes, and then peeled from the release paper to produce a film-shaped sample. prepared.

The prepared sample was attached to a SUS304 substrate by pressing it with a 2kg roller, and after 24 hours, it was peeled off at a speed of 5 mm/s using UTM (AMETEK, LS1), and the peel strength was measured. A total of 4 measurements were made using the above method. So, the average value was shown.

5. Loop take measurement

Samples were prepared and measured according to ASTM D6195. The photocurable composition was coated to a thickness of 50 ㎛ between the PET substrate and the release paper and cured by irradiating a blue LED (λ: 455 nm, intensity: 15 mW/cm ² ) for 15 minutes, and then peeled from the release paper to produce a film-shaped sample. prepared.

The prepared sample was processed to a size of 10 mm Later, the force was measured by peeling in the opposite direction at the same speed. The value was obtained by integrating the measured force with the area attached to the SUS304 substrate, and the average value was expressed by measuring a total of 4 times using the above method.

6 Rheometer measurements

The photocurable composition was coated to a thickness of 100 ㎛ between release papers, and cured by irradiating a blue LED (λ: 455 nm, intensity: 15 mW/cm ² ) for 15 minutes. The same method was repeated a total of times to prepare a sample with a thickness of 0.5 mm. was manufactured.

The prepared sample was processed into a circle with a diameter of 20 mm, and measured at 0.01 Hz and 100 Hz at 25 ° C. with 1% strain using a rheometer (Discovery HR20, TA company), and expressed as G and G″.

7. Lap shear strength measurement

The photocurable composition was coated between two identical glass plates with a thickness of 100 ㎛ and an area of 25 mm × 10 mm, and then cured by irradiating LED (λ: 455 nm, intensity: 15 mW/cm ² ) for 15 minutes.

After curing, it was peeled off at a speed of 1 mm/min using UTM (AMETEK, LS1), and the maximum strength was measured. A total of 4 measurements were made in the same manner as above, and the average value was shown.

8. Patterning measurements

The photocurable composition was coated between release papers to a thickness of 100 ㎛, the prepared masking film was placed on the coating, and then cured by irradiating a blue LED (λ: 455 nm, intensity: 15 mW/cm ² ) for 15 minutes.

After curing, the sample was prepared by washing with acetone and removing the uncured part. The prepared sample was heated on a hot plate at 50°C and photographed with a thermal imaging camera (FLIR, FLIR P620) at 7 and 20 seconds. did.

[Examples 7 to 12]

A dispersion solution was prepared with the composition shown in Table 2 below, and 30 vol% of aluminum and 0.1 vol% of MWCNT were added to the total volume of the dispersion solution, and stirred for 6 minutes at room temperature using a paste mixer (ARE-310, Thinky). A photocurable composition was prepared.

Afterwards, it was measured using the above measurement method and is shown in Table 3 below.

[Comparative Example 11]

Acrylic Interface Pad (3M, 5571) was used and measured using the above measurement method, as shown in Table 3 below.

Acrylic oligomer
(weight%) IBOAs
(weight%) NVP
(weight%) HBA
(weight%) PEGDA
(weight%) Example 7 46.20 19.80 33.00 0 1.0 Example 8 43.30 24.75 24.27 6.20 1.0 Example 9 43.30 24.80 18.60 12.30 1.0 Example 10 43.30 30.90 12.40 12.40 1.0 Example 11 43.50 24.90 24.90 6.20 1.0 Example 12 43.75 25.00 25.00 6.25 0

thermal conductivity
(W/m·k) Young's modulus
(MPa) Elongation at break
(%) self-adhesive 90°peel
(N/cm) loop
(N/mm) Rheomter
(0.01 Hz, 100 Hz) lap shear
(MPa) G′
(Mpa) G″
(Mpa) Example 7 0.454 0.763 2.561 0.11 2.21 0.13,
0.23 0.13,
0.25 0.36 Example 8 0.385 0.385 3.366 0.56 2.92 0.19,
0.52 0.007,
0.29 0.76 Example 9 0.398 0.398 3.215 0.47 4.46 0.04,
0.16 0.005,
0.34 0.71 Example 10 0.386 0.386 3.543 0.27 3.94 0.03,
0.17 0.004,
0.33 0.59 Example 11 0.328 0.328 4.228 0.55 4.04 0.04,
0.19 0.004,
0.32 0.86 Example 12 0.343 0.342 6.508 0.46 4.01 0.04,
0.17 0.006,
0.28 0.51 Comparative Example 11 1.299 0.744 0.628 0.19 8.21 0.04,
0.31 0.010,
0.19 0.01

Looking at the thermal conductivity measurements in Table 3, Example 7 had the best value, but it was confirmed that the thermal conductivity of Examples 7 to 12 was 0.3 to 0.5 W/m·k.

This suggests that even if the composition of the dispersion solution is different, the difference in thermal conductivity according to the aluminum and MWCNT content is not greater, and the thermal conductivity level is maintained in the above range.

Looking at the Young's modulus and elongation at break in Table 3, it was confirmed that Example 7 had the largest Young's modulus and the smallest elongation at break, and Example 12 had the smallest Young's modulus and the best elongation at break.

This was confirmed to be a difference depending on the content of HBA and PEGGDA included in Examples 7 to 12, and thus suggests that the elongation and modulus are controlled by differences in the composition of the dispersion solution.

Looking at the self-adhesion in Table 3, Comparative Example 11 has the best loop take measurement value, but Examples 7 to 12 have significantly higher lap shear strength than Comparative Example 11, except for Example 7. °peel strengths are excellent.

Therefore, Examples 7 to 12 have 90°peel strengths equal to or superior to Comparative Example 11, and lap shear strength is more significant than Comparative Example 11, suggesting that they have applicability as a photocurable adhesive.

In addition, looking at the rheometer measurement results in Table 3, Examples 7 to 12 belong to region 5 in the viscoelastic window, suggesting that they can be used as general pressure-sensitive adhesives.

[Example 13]

In Example 7, a photocurable composition was prepared in the same manner as in Example 7, except that aluminum contained 50% by volume based on the total volume of the dispersion solution.

Thereafter, by measuring using the patterning measurement method described above. It is shown in Figure 5 below.

Looking at Figure 5 below, it can be seen that heat is transferred according to each pattern.

Therefore, the photocurable composition of the present invention can be patterned using a masking film, and it is possible to manufacture acrylic elastomers of complex shapes using curable 3D printing.

As described above, the present invention has been described with specific details and limited examples and comparative examples, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above-mentioned examples. Those skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

Claims (16)

A photocurable composition containing an acrylic dispersion solution, metallic particles, and carbon-based particles,
The acrylic dispersion solution is a photocurable composition comprising an acrylic oligomer, a functional monomer, and a photocatalyst represented by the following formula (1):
[Formula 1]

In Formula 1,
A ₁ is C1-C12 straight or branched chain alkylene,
A ₂ and A ₃ are independently C1-C6 straight or branched chain alkylene,
Ar ₁ and Ar ₂ are alkylene containing one or two or more selected from C6-C20 arylene, C6-C20 cycloalkylene, and C3-C20 heteroarylene,
R ₁ and R ₂ are independently hydrogen or C1-C6 straight or branched chain alkyl,
n is an integer from 1 to 20,
m is an integer from 10 to 40. According to clause 1,
In Formula 1,
A ₁ is C1-C6 straight or branched chain alkylene,
A ₂ and A ₃ are independently C1-C4 straight chain alkylene,
Ar ₁ and Ar ₂ are independently alkylene including C6-C20 arylene or C6-C20 cycloarylene,
R ₁ and R ₂ are independently hydrogen or C1-C6 straight or branched chain alkyl,
n is an integer from 1 to 10,
A photocurable composition where m is an integer of 30 to 40. According to clause 1,
In Formula 1 above.
Ar ₁ and Ar ₂ are , , , , , or Phosphorus photocurable composition. According to clause 1,
A photocurable composition wherein the acrylic oligomer is represented by the following formula (2):
[Formula 2]

In Formula 2,
m is an integer from 30 to 40,
n is an integer from 1 to 10. According to clause 1,
The acrylic dispersion solution is a photocurable composition in which the weight ratio of acrylic oligomer and functional monomer is 1:1 to 1:4. According to clause 1,
The acrylic dispersion solution is a photocurable composition containing 0.01 to 0.1% by weight of a photocatalyst. According to clause 1,
A photocurable composition in which the acrylic dispersion solution further contains 0.1 to 10% by weight of a crosslinking agent. According to clause 1,
The photocurable composition includes 1 to 50% by volume of a metal compound based on the total volume of the acrylic dispersion solution. According to clause 8,
The metal particles are one or more selected from aluminum, zinc, silicon, tin, boron, antimony, barium, manganese, titanium, calcium, magnesium, vanidium, copper, iron, and oxides thereof. Photocurable composition. According to clause 1,
The photocurable composition is a photocurable composition containing 0.01 to 0.2% by volume of carbon-based particles, based on the total volume of the acrylic dispersion solution. According to clause 10,
A photocurable composition wherein the carbon-based particles include one or two or more selected from single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphite, carbon black, carbon fiber, and fullerene. An acrylic elastomer manufactured by curing the photocurable composition selected from claims 1 to 11. According to clause 12,
The acrylic elastomer has a thermal conductivity of 0.3 W/m·k or more as measured by ASTM E 1461. According to clause 12,
The acrylic elastomer is an acrylic elastomer having a curing depth of 1 mm or more obtained by curing a photocurable composition by irradiating an LED with a wavelength of 455 nm for 5 minutes. A molded article manufactured including the acrylic elastomer of claim 12. According to clause 15,
The molded product is one or more molded products selected from the group of patterning film, soft robotics material, circuit board material, and adhesive layer.