KR20180091385A - Conductive silicone rubber composition and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a conductive silicone rubber composition and to a manufacturing method thereof. In one embodiment, the conductive silicone rubber composition comprises 100 parts by weight of a polyorganosiloxane represented by chemical formula 1 below; 20 to 70 parts by weight of silica; 0.5 to 20 parts by weight of siloxane oil having silanol groups at both terminals; 0.1 to 5 parts by weight of a curing agent; and 0.1 to 10 parts by weight of a single walled carbon nanotube (SWCNT) masterbatch. The chemical formula 1 is as defined in the detailed description. An object of the present invention is to provide the conductive silicone rubber composition having both conductivity and mechanical strength at the same time.

Description

TECHNICAL FIELD [0001] The present invention relates to a conductive silicone rubber composition and a method of manufacturing the same. BACKGROUND ART [0002]

The present invention relates to a conductive silicone rubber composition and a method for producing the same.

The silicone rubber composition is excellent in stability at high temperature and low temperature and can exhibit various hardness. It also has the advantages of chemical stability, water repellency, electrical properties and compression resistance.

On the other hand, in order to impart conductivity to the silicone rubber composition, a conductive filler such as carbon black is added. However, such a conductive filler such as carbon black is required to have a large amount, so that it is difficult to realize a low degree of hardness, and it is difficult to disperse in the production of a composition and the physical properties of the manufactured product are deteriorated. In addition, when carbon black is used, the product is implemented in black, which makes it difficult to produce products having various colors.

BACKGROUND ART [0002] The background art relating to the present invention is disclosed in Korean Patent Registration No. 10-1362753 (published on Mar. 23, 201, title of the invention: condensation reaction curing type silicone rubber composition).

An object of the present invention is to provide a conductive silicone rubber composition having both conductivity and mechanical strength at the same time.

Another object of the present invention is to provide a conductive silicone rubber composition capable of realizing various hardnesses and colors.

It is still another object of the present invention to provide a method for producing the conductive silicone rubber composition.

It is still another object of the present invention to provide a silicone rubber molded article formed from the conductive silicone rubber composition.

One aspect of the present invention relates to a conductive silicone rubber composition. In one embodiment, the conductive silicone rubber composition comprises 100 parts by weight of a polyorganosiloxane represented by Formula 1 below; 20 to 70 parts by weight of silica; 0.5 to 20 parts by weight of a siloxane oil having silanol groups at both terminals; 0.1 to 5 parts by weight of a curing agent; And 0.1 to 10 parts by weight of a masterbatch of a single walled carbon nanotube (SWCNT), wherein the single-walled carbon nanotube masterbatch comprises a siloxane oil having a viscosity of 500 to 10,000 cs 1 to 20% by weight and 80 to 99% by weight of single-walled carbon nanotubes:

[Chemical Formula 1]

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, A hydroxyalkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an amino group having 2 to 20 carbon atoms At least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is a straight or branched alkyl group having from 2 to 20 carbon atoms, 20 alkenyl group).

In one embodiment, the polyorganosiloxane may have an alkenyl group content of 0.1 to 20 mol% and a weight average molecular weight of 300,000 g / mol to 800,000 g / mol.

In one embodiment, the single-walled carbon nanotube may have an average diameter of 0.1 to 100 nm and an average length of 0.1 to 200 μm.

In one embodiment, 0.1 to 20 parts by weight of carbon black may be further added to 100 parts by weight of the polyorganosiloxane.

In one embodiment, siloxane oil, silica and polyorganosiloxane having silanol groups at both ends may be contained in a weight ratio of 1: 2 to 8: 10 to 20.

In one embodiment, the siloxane oil having a silanol group at both ends has a hydroxyl group content of 1 to 10% by weight and a kinematic viscosity of 10 to 100 cSt.

In one embodiment, the curing agent comprises at least one of an acyl-based curing agent and an alkyl-based curing agent, wherein the acyl curing agent is selected from the group consisting of benzoyl peroxide, bis (2,4-dichlorobenzoyl) Butyl cerium oxide and dicumyl peroxide, and wherein said alkyl curing agent comprises at least one of di-t-butyl peroxide and 2,5-dimethyl-2,5-di (t-butyl peroxide) And may include one or more.

In one embodiment, the conductive silicone rubber composition has a volume resistivity of 10 to 10 ¹¹ Ω · cm as measured according to ASTM D 257, a hardness (SHORE A) of 30 to 80 as measured according to ASTM D 2240, A tensile strength as measured according to ASTM D 624 of 100 to 130 kgf / cm ² and an elongation of 300 to 900%.

Another aspect of the present invention relates to a method for producing the conductive silicone rubber composition. In one embodiment, the method for preparing the conductive silicone rubber composition comprises the steps of: 100 parts by weight of a polyorganosiloxane represented by the following formula (1), 20 to 70 parts by weight of silica, and 0.5 to 20 parts by weight of a siloxane oil having silanol groups at both terminals 1 heating the mixture at 100 to 220 캜; Adding 0.1 to 10 parts by weight of a single-walled carbon nanotube masterbatch to 100 parts by weight of the polyorganosiloxane to the first mixture to prepare a second mixture; And 0.1 to 5 parts by weight of a curing agent is added to the second mixture to prepare a first cured product. The single-walled carbon nanotube master batch has a viscosity of 500 to 10,000 cs 1 to 20% by weight of siloxane oil and 80 to 99% by weight of single-walled carbon nanotubes.

[Chemical Formula 1]

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, A hydroxyalkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an amino group having 2 to 20 carbon atoms At least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is a straight or branched alkyl group having from 2 to 20 carbon atoms, 20 alkenyl group).

In one embodiment, the first cured product may be molded at a temperature of 150 to 200 ° C.

In one embodiment, the single-walled carbon nanotube masterbatch comprises a third mixture comprising 1 to 20 weight percent siloxane oil having a viscosity of 500 to 10,000 cs (at 25 占 폚) and 80 to 99 weight percent of single walled carbon nanotubes And mixing at 40 to 60 캜.

Another aspect of the present invention relates to a silicone rubber molded article formed from the conductive silicone rubber composition.

The conductive silicone rubber composition of the present invention and the molded article formed therefrom have excellent mechanical strength such as conductivity, tensile strength and tensile strength, and can realize various hardnesses and colors.

FIG. 1 is a photograph comparing the color of the conductive silicone rubber composition specimen of the comparative example according to the present invention and the present invention. FIG.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to be exemplary, self-explanatory, allowing for equivalent explanations of the present invention.

Conductive silicone rubber composition

One aspect of the present invention relates to a conductive silicone rubber composition. In one embodiment, the conductive silicone rubber composition comprises 100 parts by weight of a polyorganosiloxane represented by Formula 1 below; 20 to 70 parts by weight of silica; 0.5 to 20 parts by weight of a siloxane oil having silanol groups at both terminals; 0.1 to 5 parts by weight of a curing agent; And 0.1 to 10 parts by weight of a masterbatch of a single walled carbon nanotube (SWCNT), wherein the single-walled carbon nanotube masterbatch comprises a siloxane oil having a viscosity of 500 to 10,000 cs 80 to 99 wt% and 1 to 20 wt% of single-walled carbon nanotubes:

[Chemical Formula 1]

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, A hydroxyalkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an amino group having 2 to 20 carbon atoms At least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is a straight or branched alkyl group having from 2 to 20 carbon atoms, 20 alkenyl group).

Hereinafter, the constituent components of the conductive silicone rubber composition will be described in detail.

Polyorganosiloxane

The polyorganosiloxane is represented by the following Formula 1:

[Chemical Formula 1]

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represent a linear or branched alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms An aminoalkyl group, a hydroxyalkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, And at least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is an alkyl group having 2 to 20 carbon atoms Lt; / RTI >

Examples of the alkyl group having 1 to 10 carbon atoms in the linear or branched form include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, n-pentyl, isopentyl, neopentyl, Octyl, nonyl, and decyl.

Examples of the aminoalkyl group having 1 to 10 carbon atoms include methylamino group, dimethylamino group, ethylamino group, diethylamino group, dipropylamino group, and dibutylamino group.

In the specific examples, the hydroxyalkyl group having 1 to 10 carbon atoms includes hydroxymethyl, hydroxyethyl and hydroxypropyl.

Examples of the haloalkyl group having 1 to 20 carbon atoms include fluoroalkyl groups such as trifluoropropyl, heptafluoropentyl, heptafluoroisopentyl, tridecafluorooctyl and heptadecafluorodecyl; And chloroalkyl groups such as chloromethyl, chloroethyl and chloropropyl.

Examples of the cycloalkyl group having 3 to 15 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cyclodecyl, cyclododecyl, butylcyclopropyl, methyl Cyclopentyl, dimethylcyclohexyl, ethyldimethylcycloheptyl, and dimethylcyclooctyl.

In the specific examples, the aryl group having 6 to 12 carbon atoms includes a phenyl group, a tolyl group, a xylyl group and a naphthyl group.

In the specific examples, the aralkyl group having 7 to 20 carbon atoms includes a methylphenyl group, an ethylphenyl group, a methylnaphthyl group, and a dimethylnaphthyl group.

Examples of the alkenyl group having 2 to 20 carbon atoms in the specific examples include vinyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, decynyl, hexadecynyl and octadecynyl.

In an embodiment, the alkenyl group content of the polyorganosiloxane may be from 0.01 mol% to 20 mol%. In the above range, the curing property is excellent and the hardness and physical properties of the composition can be excellent. When the vinyl group content is less than 0.01 mol%, the tensile strength and elongation strength are decreased. When the vinyl group content is more than 20 mol%, the hardness is increased and tensile strength and elongation strength may be lowered. For example, the alkenyl group content of the polyorganosiloxane may be from 0.01 mol% to 4.5 mol%.

The weight average molecular weight (Mw) of the polyorganosiloxane may be from 300,000 g / mol to 800,000 g / mol. Within the above range, the mechanical properties and processability of the present invention can be excellent. For example from 350,000 g / mol to 700,000 g / mol.

In the present invention, the polyorganosiloxane may include two or more kinds of polyorganosiloxanes having different alkenyl groups.

In one embodiment, the polyorganosiloxane has an alkenyl group content of 0.16 mol% or more and 4.5 mol% or less, and a first polyorganosiloxane having a weight average molecular weight of 650,000 to 750,000 g / mol and an alkenyl group content of 0.01 mol% or more And a second polyorganosiloxane having a weight average molecular weight of 650,000 to 750,000 g / mol in a weight ratio of 1: 5 to 1:10. Under the above-mentioned conditions, the composition may be excellent in dispersibility and processability.

In one embodiment, the polyorganosiloxane may be a polydimethylvinylsiloxane having both terminals made of dimethylvinylsilyl groups.

The polymerization degree of the polyorganosiloxane may be 100 to 20,000. Within the above range, the mechanical properties and processability of the present invention can be excellent.

Silica

The silica is included for the purpose of reinforcing mechanical strength such as tensile and tensile strength and tear strength of the present invention. The silica may be amorphous or crystalline. The silica may include at least one of fumed silica and precipitated silica. More particularly, one or more of hydrophobic dry silica, hydrophobic wet silica, hydrophilic dry silica and hydrophilic wet silica may be used.

The silica may have a specific surface area (BET method) of 100 to 300 m < 2 > / g. The mechanical properties of the present invention can be excellent in the specific surface area. For example, 150 to 250 m < 2 > / g.

The silica may have an average particle size of 5 nm to 30 탆 and a specific gravity of 1.5 to 2.5 g / cm 3. In this range, dispersion is easy, and workability and strength can be improved. On the other hand, the particle " size " of silica in the present invention is defined as meaning the " maximum length " of the silica particles.

In the specific examples, the silica may be at least one of a silane-based surface treatment agent and a silazane-based surface treatment agent. Examples of the silane surface treating agent include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexyltrimethoxysilane, Hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, trifluoropropyltrimethoxysilane, hexamethyldisiloxane, trimethylmethoxysilane, ethyltrimethoxysilane, trimethylethoxysilane, and dimethyldiethoxysilane. .

The silazane-based surface treatment agent may include at least one of divinyltetramethyldisilazane, octamethylcyclotetrasilazane, and hexamethyldisilazane.

When the surface treatment is performed with the surface treatment agent, the silica reacts with moisture in the air to form a hydrogen bond while maintaining the appearance and transparency of the present invention, thereby suppressing an increase in plasticity, and excellent mixing and compatibility.

The silica is contained in an amount of 20 to 70 parts by weight based on 100 parts by weight of the polyorganosiloxane. When the silica is contained in an amount of less than 20 parts by weight, the mechanical properties of the present invention are poor. When the silica is contained in an amount of more than 70 parts by weight, mixing and formability are decreased and hardness of the product may be difficult to control. For example, from 25 parts by weight to 60 parts by weight. As another example, 30 parts by weight to 55 parts by weight may be included.

Carbon black

In one embodiment, the conductive silicone rubber composition may further comprise carbon black. The carbon black may exist as a structure (agglomerate) in which primary particles having an average particle diameter of several tens of nanometers are fused to each other to form a structure, and the structures are bonded by van der Waals force. In one embodiment, the carbon black may be at least one of furnace black, channel black, acetylene black, lamp black, and thermal black.

In one embodiment, 0.1 to 20 parts by weight of carbon black may be added to 100 parts by weight of the polyorganosiloxane. When the content is in the above range, the conductivity of the present invention is excellent, and the hardness can be easily controlled when the conductive silicone rubber composition is prepared. For example, 0.1 to 10 parts by weight.

At both ends Silanol groups  Have Siloxane  oil

The siloxane oil is included for the purpose of improving the mixing property and the moldability in the production of the conductive silicone rubber composition.

In one embodiment, the siloxane oil having silanol groups at both ends may have a hydroxyl group content of 1 to 10 wt% and a kinematic viscosity of 10 to 100 cSt. The moldability and the mixing property can be excellent under the above conditions.

For example, the siloxane oil may include at least one of polydimethylsiloxane and silanediol having silanol groups at both ends.

In one embodiment, 0.5 to 20 parts by weight of a siloxane oil having silanol groups at both ends relative to 100 parts by weight of the polyorganosiloxane is contained. When the siloxane oil having silanol groups at both ends is contained in an amount of less than 0.5 part by weight, bubbles are formed during the production of the composition, resulting in deterioration of moldability, appearance and mechanical properties. When the siloxane oil is contained in an amount exceeding 10 parts by weight, The physical properties may be deteriorated. For example, 1 to 8 parts by weight.

In one embodiment, the siloxane oil, silica and polyorganosiloxane having silanol groups at both ends may be contained in a weight ratio of 1: 3 to 8: 15 to 25. When included in the above weight range, the mechanical properties, formability, and mixing properties of the composition can be excellent at the same time. For example, in a weight ratio of 1: 5 to 7: 18 to 21.

Hardener

The curing agent is contained for the purpose of curing by radical reaction with an alkenyl group (vinyl group) of the polyorganosiloxane. The curing agent may include at least one of an alkyl-based and an acyl-based organic curing agent.

The acyl curing agent is selected from the group consisting of benzoyl peroxide, bis (2,4-dichloro benzoyl) peroxide, tert-butylcumyl peroxide, Dicumyl peroxide, and the alkyl-based curing agent is at least one selected from the group consisting of 2,5-dimethyl-2,5 (di-tert-butylperoxide) -di (tert-butyl peroxide) hexane, and di-tert-butylperoxide.

In one embodiment, the curing agent may include the acyl curing agent and the alkyl curing agent in a weight ratio of 1: 0.3-1. For example, bis (2,4-dichlorobenzoyl) peroxide and 2,5-dimethyl-2,5-di (t-butylperoxide) hexane may be contained in a weight ratio of 1: 0.3-1. Within the above range, the curing efficiency and mechanical properties can be excellent.

Examples of products that can be used as the curing agent in one embodiment include Akzo Nobel's Trigonox 101, Trigonox 101-50D-PD, Trigonox 101-45S-PS, Trigonox 101-45B-PD, Perkadox PD- , Lucidol S-50PS, Perkadox BC-40MB-GR (40%), Trigonox B (99%) and Trigonox T-50D-PD (50%, on silica).

The curing agent is included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the polyorganosiloxane. Within the above range, easy curing proceeds and mechanical properties are excellent. When the amount of the curing agent is less than 0.1 parts by weight, crosslinking is not easily carried out, and the mechanical properties and heat resistance of the present invention are lowered. When the curing agent is added in an amount exceeding 5 parts by weight, the time required for removing the remaining curing agent is increased , The mechanical strength may be lowered. For example, 0.5 to 5 parts by weight. For example, 0.5 to 3 parts by weight.

catalyst

In one embodiment, the conductive silicone rubber composition may further comprise a catalyst. The catalyst is included in the present invention for the purpose of promoting the curing reaction (or hydrosilylation reaction) of the conductive silicone rubber composition.

In one embodiment, the catalyst may comprise platinum. For example, at least one of fine powder platinum, platinum black, chloroplatinic acid, alcohol-modified chloroplatinic acid, chloroplatinic acid-olefin complex, chloroplatinic acid-alkenylsiloxane complex, and chloroplatinic acid-divinyltetramethyldisiloxane complex .

The platinum-based catalyst may be added in an amount of 0.0001 to 3 parts by weight based on 100 parts by weight of the polydimethylvinylsiloxane. Within this range, the curing reaction rate of the present invention can be easily controlled.

Single wall  Carbon nanotube master batch

The single-walled carbon nanotube masterbatch is included in order to secure the conductivity of the present invention and can be used in the form of a master batch to ensure dispersibility, mixing properties and moldability.

In one embodiment, the single-walled carbon nanotube masterbatch comprises 80 to 99 wt% of a siloxane oil having a viscosity of 500 to 10,000 cs (measured at 25 캜), and 1 to 20 wt% of single-walled carbon nanotubes. In one embodiment, the siloxane oil may be dimethylpolysiloxane.

When the siloxane oil having the above viscosity range is applied, the dispersibility, the mixing property and the compatibility of the present invention can be excellent. When the single-walled carbon nanotube is contained in an amount of less than 80% by weight, it is difficult to ensure conductivity. When the single-walled carbon nanotube is contained in an amount exceeding 99% by weight, dispersibility and mixing property may be deteriorated.

In one embodiment, the single-walled carbon nanotube may have an average diameter of 0.1 to 100 nm and an average length of 0.1 to 200 μm and a purity of 20 to 99%. Under the above-mentioned conditions, excellent mixability, dispersibility and conductivity can be obtained. For example, an average diameter of 0.5 to 100 nm, an average length of 0.1 to 150 占 퐉, and a purity of 50 to 80%. In one embodiment, TUBALL ( ^TM ) of OCSiAl may be used as the product name of the single-walled carbon nanotube.

In one embodiment, the single-walled carbon nanotube master batch is included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the polyorganosiloxane. When the single-walled carbon nanotube masterbatch is contained in an amount of less than 0.1 part by weight, it is difficult to secure conductivity. When the amount exceeds 10 parts by weight, the flowability of the composition may be deteriorated and the mixing property and formability may be deteriorated. For example, 2 to 7 parts by weight.

additive

One embodiment of the conductive silicone rubber composition may further contain other additives such as fillers, impact modifiers, antistatic agents, antimicrobial agents, heat stabilizers, antioxidants, mold release agents, light stabilizers, surfactants, plasticizers, lubricants, antistatic agents, dyes, Based on the total weight of the composition. The content of the additive may be 0.1 to 40 parts by weight based on 100 parts by weight of the polyorganosiloxane, but is not limited thereto.

In one embodiment, the conductive silicone rubber composition has a volume resistivity of 10 to 10 ¹¹ Ω · cm as measured according to ASTM D 257, a hardness of 30 to 80 as measured according to ASTM D 2240, The tensile strength measured is 100 to 130 kgf / cm ² , and the elongation measured according to ASTM D 624 is 300 to 900%.

Method for manufacturing conductive silicone rubber composition

Another aspect of the present invention relates to a method for producing the conductive silicone rubber composition. In one embodiment, the method for preparing the conductive silicone rubber composition comprises 100 parts by weight of a polyorganosiloxane represented by the following formula (1), 20 to 70 parts by weight of silica, and 0.5 to 20 parts by weight of a siloxane oil having silanol groups at both terminals Heating the first mixture at 100 to 220 캜; Adding 0.1 to 10 parts by weight of a single-walled carbon nanotube masterbatch to 100 parts by weight of the polyorganosiloxane to the first mixture to prepare a second mixture; And 0.1 to 5 parts by weight of a curing agent is added to the second mixture to prepare a first cured product, wherein the single walled carbon nanotube masterbatch comprises 80 to 99% by weight of a siloxane oil, 1 to 20% by weight of carbon nanotubes:

[Chemical Formula 1]

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represent a linear or branched alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms An aminoalkyl group, a hydroxyalkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, And at least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is an alkyl group having 2 to 20 carbon atoms Lt; / RTI >

The polyorganosiloxane, silica, siloxane oil, curing agent and single-walled carbon nanotube master batch can use the same components and contents as those described above, so that a detailed description thereof will be omitted.

In one embodiment, the first mixture or the second mixture may be prepared by adding 0.1 to 40 parts by weight of the polyorganosiloxane to 100 parts by weight of the polyorganosiloxane. Conventional additives such as fillers, impact modifiers, anti-drop agents, antibacterial agents, heat stabilizers, antioxidants, mold release agents, light stabilizers, surfactants, plasticizers, lubricants, antistatic agents, dyes and pigments may be added.

In one embodiment, the single-walled carbon nanotube masterbatch comprises a third mixture comprising 1 to 20 weight percent siloxane oil having a viscosity of 500 to 10,000 cs (at 25 占 폚) and 80 to 99 weight percent of single walled carbon nanotubes At 40 to 60 < 0 > C for 15 to 45 minutes. When the mixture is mixed under the above-mentioned temperature conditions, the conductivity of the present invention can be excellent when the masterbatch is produced.

In one embodiment, the third mixture may be prepared by further comprising 0.1 to 20 parts by weight of carbon black relative to 100 parts by weight of the polyorganosiloxane. The same carbon black as that described above can be used.

One embodiment of the present invention may further include a step of molding the first cured product at 150 to 200 ° C to produce a molded article. For example, the first cured product can be molded at a temperature of 150 to 200 ° C by press molding.

Molded products formed from conductive silicone rubber composition

Another aspect of the present invention relates to a molded article formed from the conductive silicone rubber composition. In one embodiment, the molded article can be used in all fields where conductivity is required.

In one embodiment, the molded article may be used for a conductive roller member or the like.

The conductive silicone rubber composition according to the present invention and the molded article formed therefrom have excellent mechanical strength such as conductivity, tensile strength and elongation strength at the same time, and various hardnesses and colors can be realized.

Hereinafter, the structure and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example  And Comparative Example

The components used in the following examples and comparative examples are as follows.

(A) a polyorganosiloxane: (A1) a first polyorganosiloxane having a weight average molecular weight of 700,000 g / mol, a vinyl group content of 0.16 mol% and a dimethylvinylsilyl group at both terminals, T5TM was used. (A2) Second polyorganosiloxane: a weight average molecular weight of 700,000 g / mol, a vinyl group content of 0.03 mol%, and T722TM of Grace Continental Korea Co., Ltd. was used.

(B) Silica: EVONIC product having a BET specific surface area of 200 m ² / g was used.

(C) Siloxane oil: (C1) Polydimethylsiloxane having a kinematic viscosity of 42 cSt and silanol groups at both ends was used. (C2) silane diol having a kinematic viscosity of 80 cSt was used.

(D) Curing agent: An acyl curing agent (bis (2,4-dichlorobenzoyl) peroxide) was used.

(E) Carbon nanotube master batch: (E1) Single walled carbon nanotube master batch: Single walled carbon nanotube (SWCNT) having an average diameter of 50 nm, an average length of 100 탆 and a purity of 75% (Disolver Mixer, Korea M-Tech) at a weight ratio of 9: 1 with siloxane oil (dimethylpolysiloxane, Shin-Etsu Co., Ltd., KF-96) having a viscosity of 1000 cc and mixed at 40 ° C for 20 minutes. Pressure three times. (E2) A multiwalled carbon nanotube (MWCNT) having an average diameter of 50 nm, an average length of 100 m and a purity of 75% was mixed with siloxane oil having a viscosity of 1000 cs (dimethylpolysiloxane, Shin-Etsu, KF-96 (Disolver Mixer, Korea M-Tech) at a weight ratio of 9: 1 and mixed at 40 ° C for 20 minutes to prepare a third mixture, which was then passed through a high-pressure homogenizer at a pressure of 1000 bar three times.

(F) carbon black was used.

(G) platinum catalyst was used.

Example  One

10 parts by weight of the first polyorganosiloxane (A1) and 90 parts by weight of the second polyorganosiloxane (A2) were mixed in a mixer (manufactured by Korea M-Tech Co., Ltd.) for 30 minutes. Then, 30 parts by weight of silica (B) (C1) and 0.1 to 1 part by weight of a pigment as an additive were charged and compounded by heating at 200 DEG C for 8 hours. Subsequently, 2 parts by weight of the single wall carbon nanotube master batch (E1) was added to the first mixture and mixed to prepare a second mixture, 2 parts by weight of the curing agent (D) was added to the second mixture, For 30 minutes for primary curing, thereby preparing a first cured product. Then, the first cured product was pressure-molded at 170 DEG C for 10 minutes to prepare a conductive silicone rubber composition specimen of 150 mm x 150 mm in size.

Example  2 to 3

A conductive silicone rubber composition test piece was prepared in the same manner as in Example 1, except that the components and contents in the following Table 1 were applied.

Example  4 to 5

In preparing the single-walled carbon nanotube master batch (E1), a conductive silicone rubber composition specimen was prepared in the same manner as in Example 1, except that carbon black was used in the amounts shown in Table 1 below.

Example  6 to 8

A conductive silicone rubber composition test piece was prepared in the same manner as in Example 1, except that the components and contents in the following Table 1 were applied.

Example  9-10

A conductive silicone rubber composition specimen was prepared in the same manner as in Example 6, except that carbon black was used in the content of the following Table 2 in preparing the single-walled carbon nanotube master batch (E1).

Example  11-13

A conductive silicone rubber composition test piece was prepared in the same manner as in Example 1 except that the components and the contents in Table 2 were applied.

Example  14-15

In preparing the single-walled carbon nanotube master batch (E1), a conductive silicone rubber composition specimen was prepared in the same manner as in Example 11, except that carbon black was used in the amounts shown in Table 2 below.

Comparative Example  1-3

A conductive silicone rubber composition specimen was prepared in the same manner as in Example 1, except that carbon black was used instead of the carbon nanotube master batch in the preparation of the second mixture in the amounts shown in Table 3 below.

Comparative Example  4 to 5

A conductive silicone rubber composition specimen was prepared in the same manner as in Example 1, except that the multi-walled carbon nanotube master batch (E2) was used in the preparation of the second mixture in the contents shown in the following Table 3.

Comparative Example  6

A conductive silicone rubber composition specimen was prepared in the same manner as in Example 1 except that the carbon nanotube master batch was excluded and 10 parts by weight of the platinum catalyst (F) was used when the curing agent (D) was added.

Example  7 to 10

A conductive silicone rubber composition test piece was prepared in the same manner as in Example 1, except that the components and contents in Table 3 were applied.

The properties of the conductive silicone rubber composition samples prepared in Examples 1 to 15 and Comparative Examples 1 to 10 were measured by the following methods, and the results are shown in Tables 4 and 5 below.

How to measure property

(1) Conductivity (? 占) m): It was evaluated according to ASTM D 257. Conductivity is expressed as volume resistance.

(2) Tensile strength (kgf / cm2) and elongation (%): Measured according to ASTM D 624.

(3) Hardness (shore A): measured by ASTM D 2240.

(4) Moldability and blending property: The blending property of the components of the conductive silicone rubber composition, the moldability at the time of press molding of the composition, and the mold release from the mold were visually observed and evaluated according to the following four criteria.

(?: Excellent,?: Excellent,?: Fair, X: poor)

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a photograph showing a comparison of colors of the conductive silicone rubber composition specimens of Examples 1, 3, and 11 and Comparative Example 2 according to the present invention. Referring to the results shown in Table 4 and FIG. 1, the conductive silicone rubber compositions of Examples 1 to 15 according to the present invention were able to produce conductive silicone rubbers having excellent conductivity and various hardnesses. The conductive silicone rubbers having tensile strength and elongation Mechanical properties were excellent. It was found that when the single-walled carbon nanotube master batch of the present invention was applied, it was possible to produce conductive silicone rubber of various colors.

In contrast, in Comparative Examples 1 to 3 in which carbon black was used instead of the single-walled carbon nanotubes of the present invention, the conductivity was lowered and the tensile strength was lowered than in the examples. In the case of Comparative Examples 4 and 5 in which the multi-wall carbon nanotubes were applied, it was found that hardness control was difficult and the tensile strength was lower than that of the present invention. In the case of Comparative Example 6 in which carbon nanotubes and carbon black were not used, the conductivity was lowered. In Comparative Examples 6 to 10, in which the composition was deviated from the content of the composition of the present invention, conductivity, tensile strength and formability were significantly lower than those of the present invention And it was found. In addition, in the case of the comparative example, it was found that it is difficult to apply a carbon black in an excess amount or to apply a multi-walled carbon nanotube, and to realize a color other than black.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (12)

100 parts by weight of a polyorganosiloxane represented by the following formula (1);
20 to 70 parts by weight of silica;
0.5 to 20 parts by weight of a siloxane oil having silanol groups at both terminals;
0.1 to 5 parts by weight of a curing agent; And
0.1 to 10 parts by weight of a single walled carbon nanotube (SWCNT) masterbatch,
Wherein the single-walled carbon nanotube masterbatch comprises 1 to 20% by weight of a siloxane oil having a viscosity of 500 to 10,000 cs (at 25 캜), and 80 to 99% by weight of single-walled carbon nanotubes. Composition:
[Chemical Formula 1]

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, A hydroxyalkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an amino group having 2 to 20 carbon atoms At least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is a straight or branched alkyl group having from 2 to 20 carbon atoms, 20 alkenyl group).
The conductive silicone rubber composition according to claim 1, wherein the polyorganosiloxane has an alkenyl group content of 0.1 to 20 mol% and a weight average molecular weight of 300,000 g / mol to 800,000 g / mol.
The conductive silicone rubber composition according to claim 1, wherein the single-walled carbon nanotube has an average diameter of 0.1 to 100 nm and an average length of 0.1 to 200 μm.
The conductive silicone rubber composition according to claim 1, further comprising 0.1 to 20 parts by weight of carbon black per 100 parts by weight of the polyorganosiloxane.
The conductive silicone rubber composition according to claim 1, wherein the siloxane oil, silica and polyorganosiloxane having silanol groups at both ends are contained in a weight ratio of 1: 2 to 8: 10 to 20.
The conductive silicone rubber composition according to claim 1, wherein the siloxane oil having silanol groups at both terminals has a hydroxyl group content of 1 to 10% by weight and a kinematic viscosity of 10 to 100 cSt.
The method of claim 1, wherein the curing agent comprises at least one of an acyl-based curing agent and an alkyl-based curing agent,
Wherein the acyl based curing agent comprises at least one of benzoyl peroxide, bis (2,4-dichlorobenzoyl) peroxide, t-butyl cumyl peroxide and dicumyl peroxide, and
Wherein the alkyl-based curing agent comprises at least one of di-t-butyl peroxide and 2,5-dimethyl-2,5-di (t-butyl peroxide) hexane.
The conductive silicone rubber composition according to claim 1, wherein the conductive silicone rubber composition has a volume resistivity of 10 to 10 ¹¹ ? Cm measured according to ASTM D 257, a hardness (SHORE A) of 30 to 80 measured according to ASTM D 2240 , The tensile strength measured according to ASTM D 264 is 100 to 130 kgf / cm ² , and the elongation measured according to ASTM D 264 is 300 to 900%.
Heating a first mixture comprising 100 parts by weight of a polyorganosiloxane represented by the following formula (1), 20 to 70 parts by weight of silica, and 0.5 to 20 parts by weight of a siloxane oil having silanol groups at both ends, at 100 to 220 캜;
Adding 0.1 to 10 parts by weight of a single-walled carbon nanotube masterbatch to 100 parts by weight of the polyorganosiloxane to the first mixture to prepare a second mixture; And
And 0.1 to 5 parts by weight of a curing agent is added to the second mixture to first cure the mixture to prepare a first cured product,
Wherein the single-walled carbon nanotube masterbatch comprises 1 to 20% by weight of a siloxane oil having a viscosity of 500 to 10,000 cs (at 25 캜), and 80 to 99% by weight of single-walled carbon nanotubes. Method of preparing composition:
[Chemical Formula 1]

Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ each independently represents a linear or branched alkyl group having 1 to 10 carbon atoms, A hydroxyalkyl group having 1 to 10 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 15 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and an amino group having 2 to 20 carbon atoms At least one of R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ is a straight or branched alkyl group having from 2 to 20 carbon atoms, 20 alkenyl group).
The method of claim 9, further comprising molding the first cured product at 150-200 ° C.
10. The method of claim 9, wherein the single-walled carbon nanotube masterbatch comprises 1 to 20% by weight of a siloxane oil having a viscosity of 500 to 10,000 cs (at 25 占 폚), and 80 to 99% 3 mixture at a temperature of 40 to 60 캜.
A molded silicone rubber article formed from the conductive silicone rubber composition according to any one of claims 1 to 8.

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