KR20180005029A - Composites having core-shell structure and rubber composition comprising the same - Google Patents

Abstract

The present invention relates to a composite having a core-shell structure and to a rubber composition comprising the same, and more particularly, to a composite having a core-shell structure, which comprises a diene-based latex core; and a shell obtained by graft-polymerizing an alkyl (meth) acrylate monomer and an alkoxysilane monomer on the core, wherein the core and the shell comprise a polyethylene glycol-based comonomer and a phosphoric anionic emulsifier, and to a rubber composition comprising the same. The composite having the core-shell structure of the present invention, makes it possible to produce rubber molded articles such as high-performance tires when used in a rubber composition by improving mechanical properties and viscoelastic characteristics of the rubber.

Description

Technical Field [0001] The present invention relates to a composite having a core-shell structure and a rubber composition comprising the same. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a composite having a core-shell structure capable of improving the mechanical properties of the rubber and at the same time improving the viscoelastic properties affecting wear resistance and dynamic properties, and a rubber composition comprising the same.

The rubber has excellent extensibility and elasticity restoring ability and can be freely selected in its shape, and can be freely added or removed by controlling the compounding or using the additive, which is widely used in various industrial fields.

In particular, in the tire industry, rubber is an essential material used for manufacturing tires, and the life and performance of the tire are greatly affected by the characteristics of the rubber.

Recently, as the demand for stability, durability and low fuel consumption of automobiles has increased, development of high performance tires capable of maintaining optimal performance on various roads and climates is required. In order to accomplish this, it is important for the tire to have good adhesion to the dry road surface and the wet road surface, so that the rotation resistance and the wet grip of the tire are properly balanced. At this time, wet grip is important for braking performance, wear resistance is the life time of tire, and rotational resistance is a decisive factor for fuel efficiency.

Generally, the wet grip and the rotational resistance of a tire largely vary depending on the viscoelastic properties of the rubber used in the production of tire tread, which is the portion of the tire that is in contact with the ground. Among the viscoelastic characteristics, the dynamic loss coefficient (tan δ) at 0 ° C is closely related to the wet grip property and the dynamic loss coefficient at 60 ° C is closely related to the rolling resistance.

Specifically, in order to lower the rolling resistance, the rubber used for the tire tread should have a high rebound resilience in the range of 60 to 100 占 폚. To improve the wet grip property, the rubber used for the tire has a high attenuation factor at 0 占 폚 Lt; RTI ID = 0.0 > 0-23 C. < / RTI >

Therefore, when the dynamic loss coefficient at 0 占 폚 is used as the corresponding value of the wet grip property and the dynamic loss coefficient at 60 占 폚 is used as the corresponding value of the rotational resistance, the dynamic loss coefficient at 0 占 폚 is large and the dynamic loss coefficient It can be understood that both the braking performance and the fuel efficiency can be satisfied.

In order to meet these demands, various mixtures of rubber were used in tires. Typical methods include one or more rubbers (e.g., styrene-butadiene rubbers) having a relatively high glass transition temperature and one or more rubbers having a relatively low glass transition temperature (e.g., polybutadiene having a high 1,4-sheath content) , Or styrene-butadiene rubber having a low styrene content and a very low vinyl content, respectively, or a mixture composed of a polybutadiene prepared in a solution having a low vinyl content.

However, the above-mentioned rubber mixture is insufficient to satisfy both the wet gripability, the rolling resistance and the abrasion resistance of the tire, and studies have been carried out to reinforce the rubber composition with various reinforcing materials.

For example, Korean Patent Laid-Open Nos. 2011-0071607 and 2011-0073061 disclose a rubber composition for tire tread exhibiting improved processability, braking performance, wear performance, and low fuel consumption performance by including silica as a reinforcing filler in a rubber composition have.

However, since silica itself has a large number of silanol groups (-SiOH) on its surface, it shows hydrophilicity and has poor compatibility with non-polar rubber due to its strong polarity. Thus, a silane coupling agent is used to solve this problem.

The silane coupling agent reacts with the silanol group of the silica to change the polarity, which is the surface chemical property of the silica, to nonpolar to facilitate mixing with the rubber. However, since the conventional silane coupling agent contains a sulfide group, a scorch is generated at a temperature of 150 ° C or higher, resulting in deterioration of processability. Thus, the silane coupling agent is not widely used.

Japanese Patent Application Laid-Open No. 2014-084369 discloses a rubber composition comprising silica and an amide compound added thereto, and Korean Laid-Open Patent Application No. 2015-0021287 also discloses a rubber composition comprising a vinyltris (2-methoxyethoxy) silane (2-methoxyethoxy) silane, triethoxyvinylsilane, and the like.

Although the rubber compositions proposed in these patents improve the braking performance and the fuel consumption performance of the tire to some extent, the effect is insufficient and the mechanical properties and the life characteristics are deteriorated. Therefore, studies on rubber compositions which are not only easily applicable to tire materials in various industries in which rubber is used, especially in the tire industry but also have excellent mechanical properties such as tensile strength, tensile elongation, abrasion resistance and viscoelasticity It is necessary.

Korean Patent Publication No. 2011-0071607 (Jun. 29, 2011), a rubber composition for a tire tread, and a tire manufactured using the same Korean Patent Laid-Open No. 2011-0073061 (Jun. 29, 2011), a rubber composition for a tire tread, and a tire Japanese Patent Application Laid-Open No. 2014-084369 (Apr. 21, 2014), a rubber composition for tread, Korean Patent Laid-Open Publication No. 2015-0021287 (2015.03.02), rubber compositions for tire treads and tires made therefrom

The present inventors have conducted various studies to solve the above-mentioned problems. As a result, they have found that by using a composite having a core-shell structure including a polyethylene glycol comonomer and a phosphate anionic emulsifier in a core and a shell, It is possible to improve not only the mechanical properties but also the abrasion resistance and viscoelastic characteristics.

Accordingly, an object of the present invention is to provide a composite having a core-shell structure capable of improving mechanical properties, abrasion resistance and viscoelastic properties.

Another object of the present invention is to provide a rubber composition comprising the composite having the core-shell structure.

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

In order to achieve the above object,

Dienic latex cores; And

And a shell obtained by graft-polymerizing an alkyl (meth) acrylate monomer and an alkoxysilane monomer on the core,

Wherein the core and the shell comprise a polyethylene glycol-based comonomer and a phosphate-based anionic emulsifier.

The polyethylene glycol comonomer is represented by the following Formula 1 and has a number average molecular weight (M _n ) in the range of 300 to 10,000:

[Chemical Formula 1]

(Wherein R ₁ , R ₂ and n are as described in the specification)

The polyethylene glycol comonomer may be selected from the group consisting of polyethylene glycol acrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) diacrylate, and polyethylene Poly (ethylene glycol) dimethacrylate), and the like.

The phosphoric anionic emulsifier is characterized by being represented by the following formula (2)

(2)

(In the above formula (2), R ₃ , m and n are as described in the description)

Wherein the phosphate anionic emulsifier is selected from the group consisting of sodium di (hexaoxyethylene lauryl ether) phosphate, sodium di (hexaoxyethylene tridecyl ether) phosphate, sodium di (hexaoxyethylene myristyl ether) phosphate, disodium hexaoxyethylene At least one member selected from the group consisting of ether phosphate, disodium hexaoxyethylene tridecyl ether phosphate and disodium hexaoxyethylene myristyl ether phosphate.

Based on 100% by weight of the total monomer constituting the core,

20 to 60% by weight of a conjugated diene monomer; From 20 to 60% by weight of an ethylenically unsaturated aromatic monomer; 10 to 30% by weight of a crosslinking agent; 1 to 10% by weight of a polyethylene glycol comonomer; And 1 to 5% by weight of a phosphoric acid anionic emulsifier.

Based on 100% by weight of the total monomer constituting the shell,

50 to 80% by weight of an alkyl (meth) acrylate monomer; 10 to 40% by weight of an alkoxysilane monomer; 1 to 10% by weight of a polyethylene glycol comonomer; And 1 to 5% by weight of a phosphoric acid anionic emulsifier.

The composite having the core-shell structure has a composition of 100 wt%

40 to 80% by weight of cores; And 20 to 60% by weight of the shell.

The present invention also provides a rubber composition comprising the composite having the core-shell structure.

In addition, the present invention provides a rubber molded article produced from the above rubber composition.

The composite having a core-shell structure according to the present invention comprises a polyethylene glycol comonomer and a phosphoric acid anionic emulsifier in the core and shell, thereby improving the specific gravity, tensile strength and tensile elongation characteristics of the rubber containing the same, And viscoelastic properties.

Thus, a rubber molded article made from a rubber composition containing the composite having the core-shell structure, for example, a tire, can satisfy both mechanical characteristics, fuel consumption performance, braking performance and life performance, thereby enhancing product competitiveness as a high performance tire.

The present invention provides a composite having a core-shell structure capable of improving the mechanical, abrasion and viscoelastic properties of rubber.

Rubber is widely used in various fields, and it is an important material that determines the life and performance of tires, especially the materials used in tires.

Generally, tires should support the heavy load of the car body, so they should have high tensile strength and good durability while maintaining proper elongation. In addition, it should not be damaged by impact during running, and it must withstand torsion in left and right direction while not being severely worn. Therefore, it should have a high tear strength, wear resistance and absorb shock well. In addition, the rolling resistance must be low so that the energy loss during driving is minimized, the fuel economy is high and the heat generation is suppressed. As the speed of the automobile increases from the wet road surface to the dry road surface, The viscoelastic characteristics that affect the dynamic properties such as high wet grip property should be excellent. However, in order to improve the fuel economy, if the friction with the tire surface is reduced, the braking performance is lowered, and the rotational resistance and the wet grip property are opposite to each other.

A reinforcing material is added to the rubber composition for tire manufacturing in order to simultaneously improve physical properties such as mechanical strength, impact absorption and durability of the tire as well as wet gripability and rotational resistance. Carbon black is well dispersed in rubber and has good tensile and abrasion properties. However, the carbon black has a limitation that the braking performance and the fuel consumption performance of the tire can not be simultaneously improved.

On the other hand, a considerable amount of carbon black is being replaced by silica because addition of silica improves both braking performance and fuel efficiency. Unlike rubber-friendly carbon black, silica is hydrophilic and does not mix well with hydrophobic rubber, so a separate additive is needed to link the rubber with silica in a covalent bond. In addition, although the dynamic properties of the rubber are improved due to the addition of silica, there is a problem that irreversible deformation occurs due to the cohesion of hydroxyl groups, which are hydrophilic functional groups on the surface, and collapse under dynamic conditions when applied to a tire.

Accordingly, in the present invention, in order to improve the specific gravity, tensile strength, tensile elongation and abrasion resistance of a tire, and to satisfy both rotational resistance and wet grip property, it is used as a reinforcing material of rubber, And a core-shell structure comprising a cationic anionic emulsifier.

Specifically, a composite having a core-shell structure according to an embodiment of the present invention includes a diene-based latex core and a shell comprising an alkyl (meth) acrylate monomer formed on the core and an alkoxysilane monomer, And the shell include polyethylene glycol-based comonomers and phosphoric anionic emulsifiers. The composite of the present invention is excellent in compatibility with a rubber composition and improves the viscoelastic properties of the rubber, which affects the fuel consumption performance and the braking performance of the rubber molded product, for example, a tire produced therefrom, and simultaneously improves the mechanical properties and wear characteristics .

The core according to one embodiment of the present invention may be a polymer derived from a mixture comprising a conjugated diene monomer, an ethylenically unsaturated monomer, a crosslinker, a polyethylene glycol comonomer, and a phosphate anionic emulsifier. Particularly, in the core according to the present invention, the polyethylene glycol comonomer improves the cross-linking density of the core and the phosphate anionic emulsifier enhances the stability of the core to effectively form a shell.

The conjugated diene monomer serves to lower the glass transition temperature of the composite having the core-shell structure to improve cold resistance of the rubber containing the same.

The conjugated diene-based monomer may be at least one selected from the group consisting of 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3-ethyl- At least one selected from the group consisting of pentadiene and chloroprene can be used. And preferably 1,3-butadiene.

The conjugated diene monomer may be used in an amount of 20 to 60% by weight, preferably 25 to 55% by weight, based on 100% by weight of the total monomers constituting the core. If the content of the conjugated diene monomer is less than the above range, the cold resistance of the rubber is lowered due to an increase in the glass transition temperature of the composite. On the contrary, when the content exceeds the above range, the oil resistance of the rubber is deteriorated and the tensile strength is lowered .

The ethylenically unsaturated aromatic monomer serves to control the glass transition temperature of the composite having the core-shell structure to have an appropriate value without excessively lowering the glass transition temperature.

The ethylenically unsaturated aromatic monomer may be selected from the group consisting of styrene,? -Methylstyrene, isopropylphenyl naphthalene, vinyl naphthalene, alkylstyrene substituted with alkyl group having 1 to 3 carbon atoms, and halogen substituted styrene. Preferably styrene.

The ethylenically unsaturated aromatic monomer may be used in an amount of 20 to 60% by weight, preferably 25 to 55% by weight, based on 100% by weight of the total monomers constituting the core. At this time, if the content of the ethylenically unsaturated aromatic monomer is out of the above range, the glass transition temperature of the composite may be lowered or increased, resulting in deteriorated mechanical and chemical properties of the rubber.

The core may contain a conjugated diene monomer and an ethylenically unsaturated aromatic monomer in a weight ratio of 7: 3 to 3: 7, preferably in a weight ratio of 3: 5 to 5: 3.

The crosslinking agent serves to control the degree of crosslinking of the core. Examples of the crosslinking agent include divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butyl At least one selected from the group consisting of ethylene glycol dimethacrylate, ethylene glycol dimethacrylate, arylene glycol dimethacrylate, aryl methacrylate and 1,3-butylene glycol diacrylate. Preferably, it may be divinylbenzene.

The crosslinking agent may be used in an amount of 10 to 30% by weight, preferably 15 to 25% by weight, based on 100% by weight of the total monomers constituting the core. If the content of the crosslinking agent is less than the above range, the crosslinking reaction of the core is insufficient, and the durability and abrasion resistance of the composite and the rubber composition containing the crosslinking agent are deteriorated. If the content exceeds the above range, the crosslinking reaction becomes insufficient due to excessive crosslinking reaction. The elasticity of the composite and the finally obtained rubber may be lowered.

The polyethylene glycol-based comonomer is polymerized together with the conjugated diene-based monomer and the ethylenically unsaturated aromatic monomer to improve the cross-linking density of the core to improve the mechanical properties and life characteristics of the rubber.

The polyethylene glycol-based comonomer may be to be represented by the formula (1), the number average molecular weight (M _n) of 300 to 10,000 range:

(In the formula 1,

R ₁ and R ₂ are the same or different and each independently hydrogen; Methyl group; Or a (meth) acrylate group,

and n is an integer of 3 to 14)

The polyethylene glycol comonomer may be at least one selected from the group consisting of polyethylene glycol acrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) diacrylate, and polyethylene glycol Poly (ethylene glycol) dimethacrylate), but the present invention is not limited thereto. And preferably polyethylene glycol methacrylate.

The polyethylene glycol comonomer may be used in an amount of 1 to 10% by weight, preferably 2 to 5% by weight based on 100% by weight of the total monomers constituting the core. If the content of the polyethyleneglycol comonomer is out of the above range, the desired degree of crosslinking of the core can not be obtained and the physical properties of the rubber can be lowered.

The phosphate anionic emulsifier stabilizes the core and thereby enhances the graft rate of the shell, which is a graft polymer formed on the core.

The polyoxyethylene alkylether phosphate sodium (PAP) represented by the following formula (2) is used as the phosphate anionic emulsifier:

(In the formula 2,

R ₃ is an alkyl group having 10 to 15 carbon atoms,

m is 1 or 2,

and n is an integer of 4 to 8)

In Formula 2, R ₃ is an alkyl group having 10 to 15 carbon atoms and preferably an alkyl group having 12 to 14 carbon atoms. If the carbon number of R ₃ is less than the above range, the hydrophobic property is insufficient to weaken the emulsifying function. On the other hand, when the carbon number is more than the above range, the viscosity of the R ₃ is high.

Specifically, the phosphate anionic emulsifier is selected from the group consisting of sodium di (hexaoxyethylene lauryl ether) phosphate, sodium di (hexaoxyethylene tridecyl ether) phosphate, sodium di (hexaoxyethylene myristyl ether) phosphate, disodium hexaoxy And at least one selected from the group consisting of ethylene lauryl ether phosphate, disodium hexaoxyethylene tridecyl ether phosphate and disodium hexaoxyethylene myristyl ether phosphate. And preferably sodium di (hexaoxyethylene lauryl ether) phosphate.

The phosphate anionic emulsifier may be used in an amount of 1 to 5% by weight, preferably 1 to 3% by weight based on 100% by weight of the total monomers constituting the core. If the content of the phosphate anionic emulsifier is less than the above range, sufficient emulsification function can not be performed. If the content of the phosphate anionic emulsifier is more than the above range, the stability of the core may be deteriorated.

The shell according to an embodiment of the present invention may be formed so as to surround the above-mentioned core and may include an alkyl (meth) acrylate monomer, an alkoxysilane monomer, a polyethylene glycol comonomer, and a phosphoric acid anionic emulsifier .

The alkyl (meth) acrylate monomer is a monomer which is a basic composition of the shell in the composite according to the present invention. Examples of the monomer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, At least one selected from the group consisting of stearyl acrylate, methyl methacrylate, n-butyl methacrylate, benzyl methacrylate, lauryl methacrylate and stearyl methacrylate can be used. Preferably methyl methacrylate.

The alkyl (meth) acrylate monomer may be used in an amount of 50 to 80% by weight, preferably 50 to 75% by weight based on 100% by weight of the sum of monomers constituting the shell. If the content of the alkyl (meth) acrylate monomer is less than the above range, there is a problem in dispersibility due to poor compatibility. On the other hand, if the content exceeds the above range, the content of the polyethylene glycol comonomer There may be a problem.

The alkoxysilane monomer serves to improve the compatibility between the rubber composition and the composite having the core-shell structure of the present invention.

The alkoxysilane monomer may be at least one selected from the group consisting of trimethoxysilylpropyl methacrylate, trimethoxysilylpropyl acrylate, and trimethoxysilylethylstyrene. And preferably trimethoxysilylpropyl methacrylate.

The alkoxysilane monomer may be used in an amount of 10 to 40% by weight, preferably 20 to 30% by weight, based on 100% by weight of the total monomers constituting the shell. At this time, if the content of the alkoxysilane monomer is out of the above range, the rubber composition may not be dispersed in the rubber composition, resulting in deteriorated physical properties of the rubber.

The polyethylene glycol comonomer serves to help the shell to be formed on the outside of the core without being introduced into the core in the graft polymerization of the shell, thereby improving the dispersibility and processability of the composite having the core-shell structure.

At this time, the type and content of the polyethylene glycol-based comonomer are as described above.

The phosphate anionic emulsifier enhances the shell graft ratio and further improves the compatibility with the rubber composition.

The kind and content of the phosphate anionic emulsifier are as described above.

The composite having a core-shell structure according to the present invention may comprise 40 to 80% by weight of the core and 20 to 60% by weight of the shell relative to 100% by weight of the total. If the core is contained in an amount of less than 40% by weight, the wet grip property of the rubber molded article made from the rubber composition containing the core may be deteriorated. If the core contains more than 80% by weight, And the core may not be sufficiently wrapped around the core, so that compatibility and dispersibility with the rubber composition may be deteriorated and the workability may be deteriorated.

The preparation of the composite having the core-shell structure according to an embodiment of the present invention is not particularly limited and can be produced by a method commonly known in the art.

For example, the above method may employ a polymerization method such as emulsion polymerization, suspension polymerization, solution polymerization and the like. The emulsion polymerization is a method of emulsifying a monomer of a certain composition into a non-solvent (usually water) with an emulsifier, and then polymerizing the monomer using a polymerization initiator and an oxidation-reduction catalyst. The suspension polymerization is a polymerization in which monomers of a certain composition are dispersed in a non-solvent (usually water) using a dispersing agent and then polymerization is carried out by using a polymerization initiator and an oxidation-reduction catalyst. Solution polymerization, Monomer is dissolved in a solvent and polymerization is carried out using a polymerization initiator and an oxidation-reduction catalyst. A preferred method among the above methods may be emulsion polymerization.

Specifically, the composite having the core-shell structure can be prepared through two steps of emulsion polymerization.

For example, the method for producing a composite having the core-shell structure includes the steps of preparing a diene-based latex core and graft-copolymerizing the diene-based latex core with an alkyl (meth) acrylate monomer and an alkoxysilane monomer Lt; / RTI >

Each step will be described in detail below.

First, a conjugated diene monomer, an ethylenically unsaturated monomer, a crosslinking agent, a polyethylene glycol comonomer, and a phosphoric acid anionic emulsifier are fed all at once into a reactor and subjected to a polymerization reaction at a temperature range of 30 to 90 ° C to prepare a core. At this time, the monomer mixture may be reacted with additional additives such as a comonomer or an emulsifier in a batch or the monomer may be initially added, and the additives may be added or continuously added during the reaction several times.

The polymerization reaction may further include, for example, polymerization initiators, molecular weight regulators, activators, oxidation-reduction catalysts, ionized water and the like commonly known in the art.

The polymerization initiator is not particularly limited, but a water-soluble initiator can be used. Examples thereof include inorganic peroxides such as sodium persulfate, potassium persulfate, ammonium persulfate, potassium persulfate, and hydrogen peroxide; t-butyl peroxide, cumene hydroperoxide, p-menthol hydroperoxide, di-t-butyl peroxide, t-butyl cumyl peroxide, acetyl peroxide, isobutyl peroxide, octanoyl peroxide, dibenzoyl peroxide Organic peroxides such as oxides, 3,5,5-trimethylhexanol peroxide, t-butyl peroxyisobutyrate; Nitrogen compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, and azobisisobutyric acid (butyl acid) methyl. The polymerization initiator is used in an amount of 0.00001 to 0.2 parts by weight based on 100 parts by weight of the monomer mixture.

Examples of the molecular weight regulator include, but are not limited to, mercaptans such as? -Methylstyrene dimer, t-nodecyl mercaptan, n-dodecylmercaptan and octylmercaptan; Halogenated hydrocarbons such as carbon tetrachloride, methylene chloride, and methylene bromide; And sulfur compounds such as tetraethyldiuram disulfide, dipentamethylenediamidosulfide, and diisopropylxanthogen disulfide, and may be used in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the monomer mixture.

The activator may include, but is not limited to, at least one selected from sodium hydrogensulfate, sodium formaldehyde sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, lactose, dextrose, sodium lorolene and sodium sulfate. 0.01 to 0.15 parts by weight based on 100 parts by weight of the monomer mixture.

The redox catalyst may be, for example, sodium formaldehyde sulfoxylate, ferrous sulfate, disodium ethylenediamine tetraacetate, and cupric sulfate, and may be used in an amount of 0.01 to 0.1 parts by weight per 100 parts by weight of the monomer mixture Can be used.

Subsequently, the shell containing the alkyl (meth) acrylate monomer and the alkoxysilane monomer can be produced by mixing an alkyl (meth) acrylate monomer, an alkoxysilane monomer, a polyethylene glycol comonomer and a phosphate anionic emulsifier And graft copolymerization may be carried out on the diene-based latex cores. At this time, the shell may be formed to surround the outer surface of the core.

The graft copolymerization is not particularly limited, and can be carried out by a conventionally known method in the art. For example, the graft copolymerization can be carried out under the same composition and reaction conditions as the emulsion polymerization mentioned above.

In addition, the composite having the core-shell structure may further comprise a step of preparing and then coagulating.

The aggregation may be carried out by a method commonly used in the art, and may be carried out using an acid, a salt or a polymer.

After the coagulation, the powder may be prepared by a method of dehydrating and drying the powder by a method commonly used in the art, or by a spray drying method.

The composite having the core-shell structure obtained through the above-described production method may have an average particle diameter of 30 to 100 nm.

The present invention also provides a rubber composition comprising the composite having the core-shell structure.

Particularly, the composite having the core-shell structure satisfies not only the viscoelastic characteristic that affects the dynamic properties of the rubber composition included by including the polyethylene glycol-based co-polymer and the phosphate-based anionic emulsifier in the core and shell, The abrasion resistance can also be improved. The viscoelastic characteristic is related to rotational resistance and wet gripability, and reduces rotational resistance to reduce fuel consumption and wet gripability, thereby enhancing braking (or braking) performance when driving.

Specifically, the rubber composition may include 20 to 80 parts by weight of the composite having the core-shell structure per 100 parts by weight of the rubber.

If the content of the composite having the core-shell structure is less than the above range, the effect of improving the mechanical properties and abrasion resistance of the rubber molded article made from the rubber composition containing the core-shell structure may be insufficient. On the other hand, The rotational resistance and wet grip property of the tire may be deteriorated.

The rubber composition may be a mixture in which the composite having the core-shell structure is dispersed in the rubber, and the mixture may be in the form of aggregate in which the emulsion of the rubber and the composite having the core-shell structure are mixed and agglomerated, And the composite having the core-shell structure may be simply mixed with the rubber.

The rubber is not particularly limited, and examples thereof include natural rubber; Synthetic rubbers such as diene rubbers, styrene-butadiene rubbers, isoprene rubbers, nitrile rubbers, urethane rubbers, butyl rubbers, and the like.

If necessary, various additives commonly used in this field may be further included. Examples of the additive include heat stabilizers, lubricants, impact modifiers, plasticizers, UV stabilizers, flame retardants, colorants, fillers, flame retardants, antimicrobials, mold release agents, heat stabilizers, antioxidants, light stabilizers, compatibilizers, dyes, A conventional additive such as a filler, a filler, a plasticizer, an impact modifier, an admixture, a colorant, a stabilizer, a lubricant, an antistatic agent, a pigment, a flame retardant and a vulcanization accelerator may be added alone or in admixture of two or more .

In addition, the present invention provides a rubber molded article produced from the above rubber composition.

The rubber molded article according to one embodiment of the present invention may be a tire, preferably a tire tread.

The rubber molded article, particularly the tire, made from the rubber composition comprising the composite having the core-shell structure according to the present invention can improve the mechanical properties and improve the life performance, the fuel consumption performance and the braking performance.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example 1

(1) Production of Dienic Latex Core

Into a 120 L high-pressure polymerization vessel equipped with a stirrer, 280 parts by weight of ion-exchanged water, 0.3 part by weight of buffer solution, 1.5 parts by weight of sodium di (hexaoxyethylene lauryl ether) phosphate, 0.1 part by weight of ethylenediaminetetra sodium 0.0047 parts by weight of acetic acid salt, 0.003 parts by weight of ferrous sulfate, 0.02 part by weight of sodium formaldehyde sulfoxylic acid and 0.1 part by weight of diisopropylbenzene hydroperoxide were initially charged. 30 wt% of butadiene (BD), 47 wt% of styrene (SM), 20 wt% of divinylbenzene (DVB) and poly (ethylene glycol) methacrylate (PEGMA) 3% by weight, and the mixture was polymerized at 50 DEG C for 6 hours to prepare a dienic latex core having a particle size of 260 ANGSTROM as a diene-based latex core. The polymerization conversion rate of the produced diene latex was 96%.

(2) Preparation of a composite having a core-shell structure

60% by weight (based on solid content) of the prepared diene-based latex core was charged into a closed reactor, and then nitrogen was charged. Then, 0.0094 part by weight of ethylenediaminetetra sodium acetate, 0.006 part by weight of ferrous sulfate, And 0.04 part by weight of a poxylate was added thereto. Then, a monomer mixture containing 28% by weight of methyl methacrylate, 10% by weight of trimethoxysilylpropyl methacrylate and 2% by weight of polyethylene glycol methacrylate was added, Oxyethylene lauryl ether) phosphate (30 parts by weight), ion-exchanged water (30 parts by weight) and t-butyl hydroperoxide (0.1 part by weight) were continuously added at 50 ° C for 1 hour and further graft polymerized for 1 hour to prepare diene- A composite having a core-shell structure was prepared by forming a shell on the core. Herein, the weight part represents the total amount of the dienic latex core, methyl methacrylate and trimethoxysilylpropyl methacrylate as 100 parts by weight.

The polymer particles having the core-shell structure prepared above were spray-dried at 190 DEG C and 10,000 rpm in a spray dryer (NIRO) to obtain a composite powder having a core-shell structure.

(3) Production of rubber composition

137.5 parts by weight of a butadiene rubber (SSBR 3626, 37.5% of treated distillate aromatic extract (TDAE)) was added to a 300 cc Banbury-type Haak mixer, 50 parts by weight of the obtained composite powder having a core- 2.0 parts by weight of stearic acid, 2.0 parts by weight of Z50S (EVONIK DEGUSSA, 50% carbon black / 50% bis (3-trimethoxysilylpropyltetrasulfane) 11.2 parts, zinc oxide 3.0 parts by weight, polymerized 2,2,4- 2.0 parts by weight of 1,2-dihydroquinoline (Flexsys), 1.0 part by weight of wax and 1.75 parts by weight of diphenyl guanidine (Flexsys) were charged and stirred at 80 rpm while raising the temperature from 70 캜 to 150 캜 , And further stirred for 4 minutes while maintaining the temperature at 150 캜 to obtain a primary blend.

The resulting primary blend was cooled sufficiently at room temperature for 2 hours or more, then the cooled primary blend was poured into the Banbury-type Haak mixer, and 1.5 parts by weight of sulfur as a crosslinking agent and Nt-butyl-2-benzothiazylsulfone 2.0 parts by weight of amide (Flexsys) were added and stirred at 40 DEG C at 40 rpm for 1 minute and 30 seconds to obtain a second blend.

The prepared secondary blend was molded into a 4 mm thick sheet at 50 캜 using a 6 inch roll to prepare a rubber specimen.

Example 2

A rubber specimen was prepared in the same manner as in Example 1, except that 2.5 parts by weight of sodium di (hexaoxyethylene lauryl ether) phosphate was used in preparing the core and 1 part by weight in the shell preparation.

Example 3

In producing the core, 50% by weight of butadiene, 26% by weight of styrene, 4% by weight of polyethylene glycol methacrylate and 2 parts by weight of sodium di (hexaoxyethylene lauryl ether) phosphate were used, and methyl methacrylate , 28.5% by weight of ethylene glycol dimethacrylate, 1.5% by weight of polyethylene glycol methacrylate and 0.8% by weight of sodium di (hexaoxyethylene lauryl ether) phosphate.

Comparative Example 1

Styrene was used in an amount of 50 wt%, polyethylene glycol methacrylate was not added, and sodium alkylaryl naphthalene sulfonate was added in an amount of 3.6 parts by weight instead of sodium di (hexaoxyethylene lauryl ether) phosphate. Except that polyethylene glycol methacrylate was not added and methyl methacrylate was used in an amount of 30% by weight, and sodium alkylaryl naphthalene sulfonate was added instead of sodium di (hexaoxyethylene lauryl ether) phosphate as 1 part by weight. A rubber specimen was prepared in the same manner as in Example 1.

Comparative Example 2

A rubber specimen was prepared in the same manner as in Example 1 except that 70 parts by weight of a silica filler was added without adding a composite powder having a core-shell structure.

Comparative Example 3

In the preparation of the core, polyethylene glycol methacrylate was not added and styrene was used in an amount of 50% by weight, sodium di (hexaoxyethylene lauryl ether) phosphate was added in an amount of 2 parts by weight, and polyethylene glycol methacrylate A rubber specimen was prepared in the same manner as in Example 1, except that methyl methacrylate was used in an amount of 30% by weight and sodium di (hexaoxyethylene lauryl ether) phosphate was added in an amount of 0.8 part by weight.

Comparative Example 4

46% by weight of styrene and 4% by weight of polyethylene glycol methacrylate were added without adding sodium di (hexaoxyethylene lauryl ether) phosphate in the preparation of the core, and 28.5% by weight of methyl methacrylate, A rubber specimen was prepared in the same manner as in Example 1, except that glycol methacrylate was used in an amount of 1.5% by weight and sodium alkyldiallylphthalene sulfonate was added in place of sodium di (hexaoxyethylene lauryl ether) phosphate in an amount of 1 part by weight. .

Comparative Example 5

In the production of the core, polyethylene glycol methacrylate was not added and styrene was used in an amount of 50% by weight and sodium alkylaryl naphthalene sulfonate was added in an amount of 3.6 parts by weight instead of sodium di (hexaoxyethylene lauryl ether) A rubber specimen was prepared in the same manner as in Example 1 except that 0.8 part by weight of sodium di (hexaoxyethylene lauryl ether) phosphate was added.

Comparative Example 6

In the production of the core, 46% by weight of styrene, 4% by weight of polyethylene glycol methacrylate and 2 parts by weight of sodium di (hexaoxyethylene lauryl ether) phosphate were used, and methylethylene glycol methacrylate Except that 1 part by weight of sodium alkylaryl naphthalene sulfonate was used instead of sodium di (hexaoxyethylene lauryl ether) phosphate and 30 parts by weight of methacrylate was added to the rubber specimen .

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 core Monomer
(weight%) BD ¹⁾ 30 30 50 30 - 30 30 30 30 SM ²⁾ 47 47 26 50 - 50 46 50 46 DVB ^{3 )} 20 20 20 20 - 20 20 20 20 PEGMA ^{4 )} 3 3 4 - - - 4 - 4 PAP ^{5 )} (parts by weight) 1.5 2.5 2 - - 2 - - - SANS ^{6 )} (parts by weight) - - - 3.6 - - 3.6 3.6 - Shell Monomer
(weight%) MMA ^{7 )} 70 70 71.25 75 0 75 71.25 70 75 MPS ^{8 )} 25 25 25 25 0 25 25 25 25 PEGMA 5 5 3.75 0 0 0 3.75 5 0 PAP (parts by weight) 0.5 One 0.8 - - 0.8 - 0.8 - SANS (parts by weight) - - - One - - One 0 One * The above parts by weight represent 100 parts by weight of the total amount of each of the monomers constituting the core and the shell.
1) Butadiene
2) styrene monomer
3) Dibinylbenzene
4) Polyethylene glycol methacrylate (PEGMA, poly (ethylene glycol) methacrylate)
5) Sodium di (hexaoxyethylene lauryl ether) phosphate
6) sodium alkylaryl naphthalene sulfonate
7) methyl methacrylate
8) trimethoxysilyl propyl methacrylate (trimethoxysilyl) propyl methacrylate

Experimental Example: Measurement of Physical Properties

The specific gravity, tensile strength, tensile elongation, 300% modulus, abrasion resistance, Payne effect (ΔG) and dynamic loss coefficient were measured according to the following methods in order to comparatively analyze the characteristics of the rubber specimens prepared in Examples and Comparative Examples. The results obtained are shown in Table 2 below.

(1) Specific gravity

Each of the specimens prepared in Examples and Comparative Examples was prepared as a sample of 2 cm (width) × 2 cm (length) × 3 mm (thickness), and specific gravity was measured using model AG245 manufactured by METTLER TOLEDO.

(2) Tensile strength, tensile elongation and 300% modulus

Tensile strength, tensile elongation and 300% modulus were analyzed according to ASTM D638. Each of the specimens prepared in Examples and Comparative Examples was injection-molded at 300 ° C to prepare 1/8 "samples. The specimens were allowed to stand at 23 ° C for 24 hours, and then the both ends of the samples were placed in a tensile tester (INSTRON, 4465 model) After being stuck to the staple, one staple is fixed and the other staple is pulled at a speed of 500 mm / min to obtain a load value when each specimen is elongated to 300% and a load value at the time of cutting, Tensile strength (kgf / cm ² ), tensile elongation (%), and 300% modulus (kgf / cm ² )

[Equation 1]

&Quot; (2) "

&Quot; (3) "

(3) Abrasion resistance

Each of the rubber specimens prepared in the above Examples and Comparative Examples was crosslinked at 160 캜 for 20 minutes to prepare respective samples. 152 Akron Type Abrasion Tester (Yasuda) was used to perform preliminary abrasion 500 times under 10 lb load, followed by 3000 cycles of abrasion, and volume reduction was measured.

(4) Payne effect (ΔG ') and dynamic loss factor (tan δ)

In order to analyze the Payne effect and the dynamic loss coefficient, dynamic viscoelasticity tests were carried out on each of the specimens prepared in the above Examples and Comparative Examples.

The Payne effect was obtained by a strain sweep test during the dynamic viscoelasticity test of each specimen. The dynamic viscoelasticity test was carried out at 160 ° C for 20 minutes.

In order to analyze the rotational resistance and the wet grip property, the dynamic viscoelasticity test was performed to measure the dynamic loss coefficient (tan δ).

The dynamic viscoelasticity test was carried out using a viscoelastic machine (DMTS 500N, Gabo, Germany) at a frequency of 10 Hz, a prestrain of 5%, and a dynamic strain of 0.5%, from -40 ° C to 70 ° C.

In this case, the dynamic loss coefficient at 0 ° C is a value indicating the degree of wet grip performance (braking performance) when applied to a tire, and the Payne effect and the dynamic loss coefficient at 60 ° C are the degrees of rotation resistance The higher the dynamic loss coefficient at 0 캜, the better the wet grip property, and the lower the Payne effect and the dynamic loss coefficient at 60 캜, the better the rolling resistance.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 importance
(g / cm ³⁾ 1.00 1.00 0.99 0.99 1.146 0.98 0.98 0.98 0.98 The tensile strength
(kgf / cm ² ) 220 219 224 202 232 203 210 204 208 Tensile elongation
(%) 623 617 634 556 657 558 578 562 585 300% modulus
(kgf / cm ² ) 73 73 72 78 69 77 78 79 77 Abrasion resistance
(cc) 0.0101 0.0095 0.0097 0.0156 0.0265 0.0154 0.0153 0.0140 0.151 Payne effect
(? G ',?) 213 195 202.74 327 612 324 311 317 314 tan δ (0 ° C.) 0.785 0.778 0.799 0.701 0.622 0.704 0.722 0.708 0.726 tan (60 DEG C) 0.073 0.068 0.071 0.112 0.133 0.111 0.106 0.109 0.108

As shown in Table 2, the rubbers of Examples 1 to 3 prepared using a composite having a core-shell structure containing a polyethylene glycol-based comonomer and a phosphate-based anionic emulsifier in the core and shell of the present invention Exhibits excellent specific gravity, tensile strength, tensile elongation, and 300% modulus characteristic as compared with the rubbers of Comparative Examples 1 to 6, has a significantly low Payne effect, a high dynamic loss coefficient at 0 ° C and a dynamic loss coefficient at 60 ° C Low.

Specifically, as compared to the rubber of Comparative Example 2, which does not contain a polyethylene comonomer and a phosphoric acid anionic emulsifier in the core and shell, the rubbers of Examples 1 to 3 according to the present invention have excellent mechanical and dynamic properties Respectively.

In addition, the rubber prepared in Examples 1 to 3 according to the present invention had somewhat lower tensile strength, tensile elongation and 300% modulus characteristics than the rubber of Comparative Example 2 using silica as a filler instead of the composite having a core-shell structure , But exhibited high abrasion resistance, significantly low payne effect and excellent dynamic loss coefficient. This is because the composite having the core-shell structure according to the present invention imparts mechanical properties (tensile strength and the like) to the rubber comparable to those of the silica used in Comparative Example 2, and at the same time, the abrasion resistance (life characteristic) , Rotational resistance (fuel economy performance) and wet grip performance (braking performance) can be improved.

In addition, a composite having a core-shell structure in which one of the polyethylene glycol-based monomer and the phosphate-based anionic emulsifier is used for the core and the shell, or the polyethylene glycol-based monomer and the phosphate-based anionic emulsifier is contained in either the core or shell, Compared with the rubbers of Comparative Examples 3 to 6, the rubbers of Examples 1 to 3 according to the present invention have excellent tensile strength, tensile elongation and 300% modulus, as well as payne effect, wear resistance and dynamic The loss factor is low and the dynamic loss coefficient at 0 ° C is high. Therefore, it can be understood that the mechanical characteristics and the performance characteristics required when the tire is applied are sufficiently satisfied.

Particularly, the rubber produced in the examples exhibited a maximum loss of 67% and 48%, respectively, compared to the Comparative Example at a payne effect and a dynamic loss coefficient at 60 ° C, and a dynamic loss coefficient at 0 ° C increased by 28% . Accordingly, it can be seen that the rubber composition including the composite having the core-shell structure according to the present invention satisfies the wet grip and the rotational resistance at the same time when applied to the tire, thereby achieving improved braking performance and fuel efficiency.

The composite having the core-shell structure of the present invention is used in a rubber composition to make a rubber molded article having excellent mechanical properties and viscoelastic properties.

Claims (17)

Dienic latex cores; And
And a shell obtained by graft-polymerizing an alkyl (meth) acrylate monomer and an alkoxysilane monomer on the core,
Wherein the core and shell comprise a polyethylene glycol-based comonomer and a phosphate-based anionic emulsifier. The method according to claim 1,
Wherein the polyethylene glycol-based comonomer is represented by the following Formula 1 and has a number average molecular weight (M _n ) in the range of 300 to 10,000:
[Chemical Formula 1]

(In the formula 1,
R ₁ and R ₂ are the same or different and each independently hydrogen; Methyl group; Or a (meth) acrylate group,
and n is an integer of 3 to 14) The method according to claim 1,
The polyethylene glycol comonomer may be at least one selected from the group consisting of polyethylene glycol acrylate, poly (ethylene glycol) methacrylate, poly (ethylene glycol) diacrylate, and polyethylene glycol Dimethacrylate, and dimethacrylate. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
The phosphate-based anionic emulsifier is represented by the following formula (2): < EMI ID =
(2)

(In the formula 2,
R ₃ is an alkyl group having 10 to 15 carbon atoms,
m is 1 or 2,
and n is an integer of 4 to 8) The method according to claim 1,
The phosphate anionic emulsifier may be selected from the group consisting of sodium di (hexaoxyethylene lauryl ether) phosphate, sodium di (hexaoxyethylene tridecyl ether) phosphate, sodium di (hexaoxyethylene myristyl ether) phosphate, disodium hexaoxyethylene lauryl Wherein the core-shell structure is at least one selected from the group consisting of ether phosphate, disodium hexaoxyethylene tridecyl ether phosphate and disodium hexaoxyethylene myristyl ether phosphate. The method according to claim 1,
Based on 100% by weight of the total monomer constituting the core,
20 to 60% by weight of a conjugated diene monomer;
From 20 to 60% by weight of an ethylenically unsaturated aromatic monomer;
10 to 30% by weight of a crosslinking agent;
1 to 10% by weight of a polyethylene glycol comonomer; And
And 1 to 5% by weight of a phosphoric acid anionic emulsifier. The method according to claim 6,
The conjugated diene-based monomer may be at least one selected from the group consisting of 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 2,4-dimethyl-1,3-pentadiene, 3-ethyl- Wherein the core-shell structure is at least one selected from the group consisting of polytetrafluoroethylene, pentadiene, and chloroprene. The method according to claim 6,
Wherein the ethylenically unsaturated aromatic monomer is at least one member selected from the group consisting of styrene,? -Methylstyrene, isopropylphenylnaphthalene, vinylnaphthalene, alkylstyrene substituted with an alkyl group having 1 to 3 carbon atoms, and halogen-substituted styrene ≪ / RTI > having a core-shell structure. The method according to claim 6,
The crosslinking agent may be at least one selected from the group consisting of divinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, aryl methacrylate, and 1,3 -Butylene glycol diacrylate. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
Based on 100% by weight of the total monomer constituting the shell,
50 to 80% by weight of an alkyl (meth) acrylate monomer;
10 to 40% by weight of an alkoxysilane monomer;
1 to 10% by weight of a polyethylene glycol comonomer; And
And 1 to 5% by weight of a phosphoric acid anionic emulsifier. 11. The method of claim 10,
The alkyl (meth) acrylate monomer may be selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, methyl methacrylate, Methacrylate, methacrylate, methacrylate, methacrylate, methacrylate, lauryl methacrylate and stearyl methacrylate. 11. The method of claim 10,
Wherein the alkoxysilane monomer is at least one selected from the group consisting of trimethoxysilylpropyl methacrylate, trimethoxysilylpropyl acrylate, and trimethoxysilylethylstyrene. The method according to claim 1,
The composite having the core-shell structure has a composition of 100 wt%
40 to 80% by weight of cores; And
And 20 to 60% by weight of the shell. With respect to 100 parts by weight of the rubber,
A rubber composition comprising 20 to 80 parts by weight of a composite having a core-shell structure according to any one of claims 1 to 13. 15. The method of claim 14,
Wherein the rubber is at least one selected from the group consisting of natural rubber, diene rubber, styrene-butadiene rubber, isoprene rubber, nitrile rubber, urethane rubber and butyl rubber. Rubber composition. A rubber molded article produced from the rubber composition according to claim 14. 17. The method of claim 16,
Wherein the rubber molded article is a tire.