KR20230067318A - Composition for epoxy-based structural adhesive - Google Patents

Abstract

The present invention relates to an epoxy-based structural adhesive composition. More specifically, provided is an epoxy-based structural adhesive composition including: a main material unit including a) 50 to 70 wt% of one or more epoxy resins, b) 15 to 25 wt% of an elastomeric toughening agent having terminal isocyanate groups in which core-shell rubber particles are dispersed, and c) 15 to 25 wt% of additives; and a curing agent unit. Provided is a two-component epoxy-based structural adhesive composition with improved mechanical properties such as adhesion and impact strength by using the toughening agent.

Description

Epoxy-based structural adhesive composition {COMPOSITION FOR EPOXY-BASED STRUCTURAL ADHESIVE}

The present invention relates to epoxy-based structural adhesive compositions, and more particularly to two-part epoxy-based structural adhesive compositions containing an elastomeric toughening agent having terminal isocyanate groups containing core-shell rubber particles.

Structural adhesives are materials having properties capable of bonding high-strength materials such as wood, composites, or metals to each other, and are particularly used in industries requiring high functionality, such as automobiles, aerospace industries, and ships. Rather than joining structures by welding or mechanical methods, bonding using adhesives increases work speed, reduces costs, and is more preferred because there is no problem of corrosion due to potential difference between materials.

In particular, the greatest advantage of structural adhesives used in transportation industries such as automobiles is that they can be reduced in weight by using structural adhesives rather than mechanical bonding methods. As such, structural adhesives applied to the automobile field require durability capable of withstanding large impacts such as vehicle collisions. In addition, physical properties such as adhesive strength, impact peel strength, and elasticity should be excellently maintained even in a wide temperature range.

Epoxide resin adhesive has excellent adhesion, durability, physical properties, etc., and its properties can be changed relatively easily depending on the combination of the main agent and the curing agent, so it is widely used in fields such as electricity, civil engineering, and construction. .

Existing automotive structural adhesives are high-temperature curing, one-component adhesives used for bonding steel materials. However, when the existing one-component structural adhesives are applied to the bonding of heterogeneous materials such as aluminum (Al) due to the recent weight reduction of automobile bodies, the thermal expansion coefficient between the vehicle body material and the adhesive is applied. Due to the large difference, severe external deformation occurs during high temperature curing.

Accordingly, two-component structural adhesives cured at room temperature are being actively researched and developed, but there is still a need for a material capable of realizing high-strength adhesion between aluminum and composite materials and realizing conventional impact strength.

Republic of Korea Patent Publication No. 10-2011-0034673 (published on April 5, 2011)

In order to solve the above problems, an object of the present invention is to provide an epoxy-based structural adhesive composition comprising an elastomeric toughener having terminal isocyanate groups containing core-shell rubber particles.

In order to achieve the above object, the present invention provides a) 50 to 70% by weight of one or more epoxy resins, b) 15 to 25% by weight of an elastomeric toughener having terminal isocyanate groups in which core-shell rubber particles are dispersed, and c ) a main part containing 15 to 25% by weight of additives; And a curing agent unit; provides an epoxy-based structural adhesive composition comprising a.

The epoxy resin may include 30 to 40% by weight of a bisphenol-type epoxy resin and 20 to 30% by weight of a modified epoxy resin in which rubber particles are dispersed in the bisphenol-type epoxy resin.

The toughening agent is polybutadiene, polyethylene oxide (PEO), polytetramethylene oxide (PTMO), polypropylene oxide (PPO), polyisobutylene, polyethylene adipate (poly(ethylene adipate)) or polycaprolactone (polycaprolactone) After dispersing the core-shell rubber particles in one polyol or a mixture of two or more polyols selected from the group consisting of a diol, a triol, and a tetraol, a polyisocyanate-based compound is added to may have reacted.

The additive may be one or more selected from the group consisting of a filler, a reactive diluent, an inorganic filler, and a coupling agent.

The main part and the curing agent part may be included in a weight ratio of 1: (0.3 to 0.7).

By using the elastomeric toughener having a terminal isocyanate group containing core-shell rubber particles according to the present invention, a two-component epoxy-based structural adhesive composition having improved mechanical properties such as adhesive strength and impact strength can be provided.

By using the two-component epoxy-based structural adhesive composition, problems occurring in existing one-component adhesive compositions can be solved and more effectively utilized as automotive structural adhesives.

Hereinafter, the present invention will be described in detail.

The terms used in the present invention have been selected from general terms that are currently widely used as much as possible while considering the functions in the present invention, but these may vary depending on the intention of a person skilled in the art or precedent, the emergence of new technologies, and the like. Therefore, the term used in the present invention should be defined based on the meaning of the term and the overall content of the present invention, not simply the name of the term.

When it is said that a certain part "includes" a certain component throughout the specification, it means that it may further include other components without excluding other components unless otherwise stated.

The present invention provides an epoxy-based structural adhesive composition.

The epoxy-based structural adhesive composition according to the present invention may be a two-component adhesive composition including a main part and a curing agent part.

In the epoxy-based structural adhesive composition according to the present invention, the main part comprises a) 50 to 70% by weight of at least one epoxy resin, b) 15 to 25% by weight of an elastomeric toughener having terminal isocyanate groups, and c) 15 to 70% by weight of an additive 25% by weight.

As the epoxy resin, a curable epoxy resin containing an epoxy group may be used. The epoxy resin is not limited to its type, and an epoxy resin commonly used in epoxy adhesives may be used. For example, a monoepoxy compound, a multivalent epoxy compound, or a mixture thereof may be used.

The mono-epoxy compound, for example, butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether ether), para-butylphenyl glycidyl ether, para-xylyl glycidyl ether, glycidyl acetate, glycidyl butyrate butyrate), glycidyl hexoate, glycidyl benzoate, or mixtures thereof.

Examples of the polyhydric epoxy compound include bisphenol-type epoxy resins, polyhydric phenol-type epoxy resins obtained by glycidylation, novolak-type epoxy resins, aliphatic ether-type epoxy resins, ether ester-type epoxy resins, ester-type epoxy resins, and amine-type epoxy resins. Epoxy resins, alicyclic epoxy resins, or mixtures thereof.

As said bisphenol type epoxy resin, for example, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S, tetrabromobisphenol A, tetra Chlorobisphenol A, tetrafluorobisphenol A, or mixtures thereof; and the like. The bisphenol-type epoxy resin may be used in a liquid or solid state at room temperature.

As the epoxy resin obtained by glycidylating the polyhydric phenol type, for example, a dihydric phenol type such as biphenol, dihydroxynaphthalene, 9,9-bis(4-hydroxyphenyl)fluorene, etc. Cydylated epoxy resins, glycidylated epoxy resins of trisphenol type such as 1,1,1-tris(4-hydroxyphenyl)methane, 1,1,2,2-tetrakis(4-hydroxyphenyl) ) Epoxy resin obtained by glycidylating a tetrakisphenol type such as ethane or a mixture thereof; and the like.

The novolak-type epoxy resin is, for example, an epoxy obtained by glycidylating a novolak type such as a phenol novolak type, a cresol novolak type, a bisphenol A novolak type, a brominated phenol novolak type, or a brominated bisphenol A novolak type. resins or mixtures thereof; and the like.

As said aliphatic ether-type epoxy resin, the epoxy resin which glycidylated polyhydric alcohol, such as glycerol and polyethylene glycol, or mixtures thereof, etc. are mentioned, for example.

Examples of the ether ester type epoxy resin include epoxy resins obtained by glycidylating hydroxycarboxylic acids such as paraoxybenzoic acid, or mixtures thereof.

As said ester type epoxy resin, the epoxy resin which glycidylated polycarboxylic acid, such as phthalic acid and terephthalic acid, or mixtures thereof, etc. are mentioned, for example.

Examples of the amine type epoxy resin include epoxy resins obtained by glycidylating amine compounds such as 4,4-diaminodiphenylmethane and m-aminophenol, or mixtures thereof.

Examples of the alicyclic epoxy resin include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, 1,2-epoxy-4-vinylcyclohexane, and bis(3,4). -Epoxycyclohexylmethyl) adipate, 1-epoxyethyl-3,4-epoxycyclohexane, limonene diepoxide, 3,4-epoxycyclohexylmethanol, or mixtures thereof.

The epoxy resin may include a modified epoxy resin in which core-shell rubber particles are dispersed.

According to one embodiment of the present invention, the epoxy resin may include both a bisphenol-type epoxy resin and a modified epoxy resin, and the epoxy resin may be included in an amount of 50 to 70% by weight.

More specifically, the bisphenol-type epoxy resin may be a bisphenol A-type epoxy resin, and the bisphenol-A type epoxy resin may be 30 to 40% by weight, preferably 35% by weight, but is not limited thereto. If the content of the bisphenol A-type epoxy resin is too small, there may be problems with adhesion and bonding strength in the adhesive, and if the content is too large, a problem of deteriorating adhesion may occur, so the above range is preferable.

More specifically, the modified epoxy resin is a bisphenol A type epoxy resin; and a methyl methacrylate butadiene styrene (MBS) system in which rubber particles are dispersed throughout the methyl methacrylate-styrene polymer matrix. 70% by weight and 30 to 40% by weight of the MBS system may be mixed, and the modified epoxy resin may be included in 20 to 30% by weight, preferably 25% by weight, but is not limited thereto.

The toughening agent may be prepared by rapidly dispersing core-shell rubber particles in a polyol or a polyol mixture prepared by mixing two or more different polyols, and then adding and reacting with a polyisocyanate-based compound.

The polyol may be selected from an aliphatic polyol or an aromatic polyol. This refers to a compound each including an aliphatic linking group or an aromatic linking group as a linking group and including two or more hydroxyl groups (—OH), and any one commonly used in the art may be used without particular limitation.

More specifically, the aliphatic polyol is 2,4-pentanediol, 2,3-pentanediol, 2-methyl-2,4-pentanediol, 2,4-dimethyl-2,4-pentane diol, 2,4,4-trimethyl-2,3-pentanediol, 1,5-pentanediol, 1,4-butanediol, 1,6-hexanediol, 3-methylpentane-1, 5-diol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonandiol, 1,10-decanediol, 1,12-dodecanediol, 1,6-hexane oligomers of diols, ethylene glycol and propylene glycol, and polycondensation polymers therefrom, but are not limited thereto.

The aromatic polyol is a polyol containing an aromatic linking group, and may include, for example, a naphthalene structure, but is not limited thereto.

The core-shell rubber particles may be butadiene-based rubber particles, but are not limited thereto.

The polyisocyanate-based compound is a reactive monomer containing two or more isocyanate groups (-NCO) and may be used without particular limitation as long as it is commonly used in the art. Specifically, for example, it may be any one or a mixture of two or more selected from aromatic diisocyanate compounds, aliphatic diisocyanates, and alicyclic diisocyanates.

In the case of using the alicyclic diisocyanate compound, it may be preferred in that it can express high flexibility when applied to an epoxy composition for adhesives, but is not limited thereto.

For example, the aromatic diisocyanate is 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, 4,4'-di Phenylmethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3 '-Dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, 4,4',4"-triphenylmethanetriisocyanate, m-isocyanatophenylsulfonylisocyanate and p -Isocyanatophenylsulfonylisocyanate and the like, but is not limited thereto.

Aliphatic diisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, Lysine diisocyanate, 2,6-diisocyanatomethylcaproate, bis(2-isocyanatoethyl)fumarate, bis(2-isocyanatoethyl)carbonate and 2-isocyanatoethyl-2,6 - It may be diisocyanatohexanoate or the like, but is not limited thereto.

The alicyclic diisocyanate isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis( 2-isocyanatoethyl) -4-dichlorohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, and the like, but is not limited thereto. .

According to one embodiment of the present invention, preferably, the toughening agent is a polyol having 2 to 4 hydroxyl groups (—OH), for example, polybutadiene, polyethylene oxide (PEO), polytetramethylene oxide (PTMO) consisting of diols, triols and tetraols of polypropylene oxide (PPO), polyisobutylene, poly(ethylene adipate) or polycaprolactone. After high-speed dispersion of butadiene-based core-shell rubber particles in one polyol or a mixture of two or more polyols selected from the group, more preferably a mixture of polyester polyol and polybutadiene diol made of dimer diol, aliphatic diisocyanate, Preferably, it may be prepared by adding and reacting 1,6-hexamethylene diisocyanate, and the toughening agent may be included in an amount of 15 to 25% by weight, preferably 20% by weight.

The additive may be one or more selected from the group consisting of a filler, a reactive diluent, an inorganic filler, and a coupling agent.

The filler may improve workability by adjusting the viscosity of the main part or the curing agent part and further improving the flowability of the epoxy-based adhesive composition. For example, the filler is silica, alumina, barium sulfate, talc, mud, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, calcium titanate, magnesium titanate , bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, or a mixture thereof, but is not limited thereto, and the silica may specifically be fumed silica.

According to one embodiment of the present invention, the filler may be included in 10 to 15% by weight in the main part.

The reactive diluent is neophenyl glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,4-butanediol glycidyl ether, ethylene glycol diglycidyl ether, 1,6-hexanediol glycidyl diyl ether, 1,4-cyclohexane dimethanol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like, but is not limited thereto.

According to one embodiment of the present invention, the reactive diluent may be included in an amount of 1 to 10% by weight in the main part.

In addition, the composition is a stabilizer, a surfactant, a flow modifier, a pigment, a dye, a matting agent, a degassing agent, a filler, a flame retardant, a curing initiator, a curing inhibitor, a wetting agent, a colorant, a pigment, a thermoplastic agent, a processing aid, and ultraviolet (UV) blocking It may further include any one or two or more additives selected from compounds, fluorescent compounds, UV stabilizers, antioxidants, and release agents, which may be used within a range that does not impair physical properties of the epoxy-based adhesive composition.

In the epoxy-based structural adhesive composition according to the present invention, the curing agent part may include i) 55 to 65 wt% of one or more curing agents, and ii) 35 to 45 wt% of additives.

The curing agent as curing an epoxy resin may be used without limitation as long as it is known in the art. Specifically, for example, the curing agent may include an anhydride-based curing agent, a phenol-based curing agent, a dicyan diamide-based curing agent, an amine-based curing agent, and a rubber-based curing agent, and may be used alone or in combination of two or more.

Preferably, the curing agent is an amine-based curing agent, and more specifically, an aliphatic amine, an aliphatic polyamine, an aromatic polyamine, a polyamide polyamine, a modified aromatic amine, or a mixture thereof may be used. Specifically, for example, the aliphatic amine curing agent is ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, polymethylenediamine, trimethylhexamethylene It may be at least one selected from diamine and polyether diamine, but is not limited thereto.

The cycloaliphatic amine curing agent is isophoronediamine, menthandiamine, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl) 2,4,8,10-tetraoxaspiro(5,5)undecane adduct , bis(4-amino-3-methylcyclohexyl)methane, bis(4-aminocyclohexyl)methane, and the like. The aromatic amine curing agent may be at least one selected from phenylenediamine, xylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, benzyldimethylamine, and dimethylaminomethylbenzene. In this case, the aromatic amine curing agent may have any form of meta (m-), ortho (o-) or para (p-) form. The modified aromatic amine may be a mixture of one or more selected from the group consisting of 4,4-diaminodiphenylmethane, meta-phenylene diamine, and diaminodiphenyl sulfone, but is not limited thereto.

The amine-based curing agent may be included in an amount of 15 to 25% by weight, and when the amine-based curing agent is included in the above range, the curing rate of the epoxy resin may be adjusted and excellent mechanical strength may be secured.

In addition, the curing agent may include a conventional rubber-based curing agent in the art, and by imparting toughness and flexibility to the epoxy-based adhesive composition according to the present invention, it will provide an effect of improving adhesive strength and improving mechanical properties at low temperatures. can

Preferably, the rubber-based curing agent may be an amine-terminated reactive liquid rubber, more preferably amine-terminated butadiene acrylonitrilem (ATBN), and may be included in an amount of 35 to 45% by weight. , but not limited to

.

The additive may be one or more selected from a curing accelerator or filler, and may be included in an amount of 35 to 45% by weight, but is not limited thereto.

The curing accelerator is used together with a curing agent to control the curing rate, and tertiary amines such as DMP-30 may be used, and may be included in an amount of 1 to 5% by weight. If the content of the curing accelerator in the curing agent unit is too small, there may be a problem in that the curing time at low temperature becomes long. .

The filler may be included in an amount of 34 to 40% by weight in the curing agent part, but is not limited thereto.

Corresponding features may be substituted in the foregoing.

In the epoxy-based structural adhesive composition according to the present invention, the main part and the curing agent part may be included in a weight ratio of 1: (0.3 to 0.7), preferably 1: 0.5, but are not limited thereto. .

The present invention also provides a method for preparing an elastomeric toughener having terminal isocyanate groups in which core-shell rubber particles are dispersed.

The toughening agent manufacturing method according to the present invention is a polyol having 2 to 4 hydroxyl groups (-OH), for example, polybutadiene, polyethylene oxide (PEO), polytetramethylene oxide (PTMO), polypropylene oxide (PPO) One polyol selected from the group consisting of a diol, a triol, and a tetraol of polyisobutylene, polyethylene adipate, or polycaprolactone or preparing a mixture of two or more polyols;

preparing a pre-polymer by adding a polyisocyanate-based compound after high-speed dispersing core-shell rubber particles in the polyol or polyol mixture; and

After blocking the prepared prepolymer, degassing in vacuum may be included.

The step of preparing the polyol or polyol mixture is the polybutadiene, polyethylene oxide (PEO), polytetramethylene oxide (PTMO), polypropylene oxide (PPO), polyisobutylene, polyethylene adipate (poly(ethylene adipate)) Alternatively, one polyol selected from the group consisting of a diol, a triol, and a tetraol of polycaprolactone is prepared, or two or more different polyols are prepared in a nitrogen atmosphere at 100 to 200 ° C. It may be performed by mixing for 10 to 60 minutes in

According to an embodiment of the present invention, 35 to 70% by weight of dimer diol or polyester polyol prepared therefrom and 10 to 20% by weight of polybutadiene diol are mixed in a nitrogen atmosphere at 100 to 200 ° C. for 10 to 60 minutes. It can be.

In the step of preparing the prepolymer, 10 to 40% by weight of butadiene-based core-shell rubber particles are dispersed at high speed in the polyol mixture prepared above, and then 5 to 15% by weight of a polyisocineanate-based compound is added to form a 60 to 60 to 40% by weight polyisocineanate compound. It can be carried out by reacting for 100 minutes.

The blocking may be performed by adding 1,3-dimethylpyrazole to the prepared prepolymer and reacting at 80 to 100° C. for 50 to 70 minutes.

Corresponding features may be substituted in the foregoing.

Hereinafter, examples will be described in detail to aid understanding of the present invention. However, the following examples are merely illustrative of the contents of the present invention, but the scope of the present invention is not limited to the following examples. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

<Example 1> Preparation of toughening agent 1

66% by weight of 1000 molecular weight dimer diol (Priplast™ 1837, Croda) and 17% by weight of polybutadiene diol (R-45HT, SATOMER) were mixed at 100°C in a nitrogen atmosphere for 30 minutes. After mixing, 12 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 5 wt% of 1,3-dimethylpyrazole was added to The blocking reaction was allowed to occur at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Example 2> Preparation of toughening agent 2

53% by weight of 1000 molecular weight dimer diol and 17% by weight of polybutadiene diol were mixed in a nitrogen atmosphere at 150° C. for 30 minutes, and then 15% by weight of butadiene-based core-shell rubber particles were dispersed at high speed. Thereafter, the temperature was lowered to 100° C., and 11 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 4 wt% of 1,3-hexamethylene diisocyanate was added. Dimethylpyrazole was added to allow a blocking reaction at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Example 3> Preparation of toughening agent 3

40% by weight of 1000 molecular weight dimer diol and 17% by weight of polybutadiene diol were mixed in a nitrogen atmosphere at 150° C. for 30 minutes, and then 30% by weight of butadiene-based core-shell rubber particles were dispersed at high speed. Thereafter, the temperature was lowered to 100° C., and 9 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 4 wt% of 1,3-hexamethylene diisocyanate was added. Dimethylpyrazole was added to allow a blocking reaction at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Example 4> Preparation of toughening agent 4

40% by weight of 2000 molecular weight dimer diol (Priplast™ 1838, Croda) and 17% by weight of polybutadiene diol were mixed in a nitrogen atmosphere at 150° C. for 30 minutes, and then 30% by weight of butadiene-based core-shell rubber particles were mixed. dispersed at high speed. Thereafter, the temperature was lowered to 100° C., and 9 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 4 wt% of 1,3-hexamethylene diisocyanate was added. Dimethylpyrazole was added to allow a blocking reaction at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Example 5> Preparation of toughening agent 5

40% by weight of 3000 molecular weight dimer diol (Priplast™ 3196, Croda) and 17% by weight of polybutadiene diol were mixed in a nitrogen atmosphere at 150° C. for 30 minutes, and then 30% by weight of butadiene-based core-shell rubber particles were mixed. dispersed at high speed. Thereafter, the temperature was lowered to 100° C., and 9 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 4 wt% of 1,3-hexamethylene diisocyanate was added. Dimethylpyrazole was added to allow a blocking reaction at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Comparative Example 1> Preparation of toughening agent A

40% by weight of 2000 molecular weight ether diol and 17% by weight of ester diol were mixed in a nitrogen atmosphere at 150° C. for 30 minutes, and then 30% by weight of butadiene-based core-shell rubber particles were dispersed at high speed. Thereafter, the temperature was lowered to 100° C., and 9 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 4 wt% of 1,3-hexamethylene diisocyanate was added. Dimethylpyrazole was added to allow a blocking reaction at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Comparative Example 2> Preparation of toughening agent B

40% by weight of 2000 molecular weight polycarbonate diol and 17% by weight of ester diol were mixed in a nitrogen atmosphere at 150° C. for 30 minutes, and then 30% by weight of butadiene-based core-shell rubber particles were dispersed at high speed. Thereafter, the temperature was lowered to 100° C., and 9 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 4 wt% of 1,3-hexamethylene diisocyanate was added. Dimethylpyrazole was added to allow a blocking reaction at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Comparative Example 3> Preparation of toughening agent C

40% by weight of 2000 molecular weight polytetramethylene ether glycol diol and 17% by weight of ester diol were mixed in a nitrogen atmosphere at 150° C. for 30 minutes, and then 30% by weight of butadiene-based core-shell rubber particles were dispersed at high speed. Thereafter, the temperature was lowered to 100° C., and 9 wt% of 1,6-hexamethylene diisocyanate was added and reacted for 80 minutes to prepare a 3.0 to 3.5 wt% NCO prepolymer, and 4 wt% of 1,3-hexamethylene diisocyanate was added. Dimethylpyrazole was added to allow a blocking reaction at 90° C. for 60 minutes. The resulting toughening agent was degassed under vacuum conditions.

<Preparation Example 1> Preparation of two-component epoxy structural adhesive formulation

Table 1 below shows formulation components and weights for preparing epoxy structural adhesives.

item ingredient weight



PART A Diglycidyl ether of bisphenol A 35 toughening agent 20 Core-shell modified epoxy ¹⁾ 25 Neophenyl glycol diglycidyl ether 5 fumed silica 2 filler 11 coupling agent 2 Sum 100


PART B triethylenetetraamine 10 ATBN ²⁾ 20 tertiary amine One fumed silica 2 filler 17 Sum 50 Mixing ratio (PART A: PART B) 2:1

* 1) A mixture in which 65% by weight of diglycidyl ether of bisphenol A and 35% by weight of MBS-based core-shell particles are dispersed

* 2) Hypro 1300x16 - Amine terminated butadiene acrylonitrile produced by Huntsman

<Analysis Example 1> Physical property analysis

1. Shear strength (MPa)

Cold rolled steel sheet (Cole Rolled steel sheet, CR) was degreased and dried using isopropyl alcohol or toluene, then the surface solvent was removed with a clean cloth, and only the dust on the surface of the aluminum (Al) specimen was removed with a clean cloth. . The size of the specimen was 100mm x 25mm x 1.6T for the CR steel plate and 100mm x 25mm x 2.0T for the Al specimen. The adhesive prepared in Examples or Comparative Examples was applied to one side of the CR and Al specimens and bonded at an overlap of 12.5 mm. After fixing with a joint clip (compressive force of about 0.3 kg), curing at 22° C. for 72 hours, the test was conducted under standard conditions of 22° C. and 65% relative humidity. A tensile load was applied to the shear strength test piece in a 180° direction at a tensile speed of 5 mm/min in a universal testing machine (SHIMADZU, AG-X plus). The maximum value of the shear strength was obtained from the load-displacement curve of the automatic recording device attached to the universal testing machine, and the average value of three tests was described.

2. T-peel strength (N/25mm)

CR and Al steel sheets with a size of 150mm x 300mm x 0.8T were degreased and dried with isopropyl alcohol or toluene, and then the surface solvent was removed with a clean cloth. After applying 25 mm x 220 mm of the adhesive prepared in Example or Comparative Example to one side of the test specimen, the other steel plate was bonded. The joint was fixed with a clip (compressive force of about 0.3 kg), cured at 22° C. for 72 hours, and then tested under standard conditions of 22° C. and 65% relative humidity. The peel strength test piece was subjected to a tensile load in the direction of 180 ° at a tensile speed of 50 mm / min in a universal testing machine (SHIMADZU, AG-X plus). The peel strength is the average value of the 50 mm length after the first maximum value from the load-displacement curve of the automatic recording device attached to the tensile tester, and the average value tested three times was entered.

3. Impact strength (N/mm)

After degreasing and drying a 90mm x 20mm x 1.6T steel sheet with isopropyl alcohol or toluene, removing residual solvent with a clean cloth, 20mm x 30mm of the adhesive prepared in the above example was applied to one side of the CR steel sheet, and then the other side steel plates were joined. The joint was fixed with a clip (compressive force of about 0.3 kg), cured at 22° C. for 72 hours, and then tested under standard conditions of 22° C. and 65% relative humidity. The test piece was tested using an impact strength tester (Instron 9250HV) under the following conditions; The impact was applied according to the drop weight (45 kg), drop height (0.2 m), and drop speed (2 m/sec). The impact strength value was the average value tested three times.

Table 2 below confirms the physical properties of the adhesives according to the toughening agents prepared according to Examples 1 to 5 and Comparative Examples 1 to 3.

No.

toughening agent Shear strength (MPa)
/destroy mode Peel Strength (N/25mm) Impact peel strength (N/mm) AI CR AI CR normal temperature
/destroy mode -40℃
/destroy mode One 1 (Example 1) 17/CF 18/CF 160/CF 180/CF 18/CF 15/CF 2 2 (Example 2) 20/CF 22/CF 200/CF 240/CF 26/CF 24/CF 3 3 (Example 3) 25/CF 27/CF 223/CF 263/CF 30/CF 26/CF 4 4 (Example 4) 27/CF 28/CF 210/CF 252/CF 28/CF 20/CF 5 5 (Example 5) 20/AF 24/CF 163/AF 180/AF 23/CF 21/CF 6 A (Comparative Example 1) 10/AF 18/CF 90/AF 130/AF 8/AF 8/AF 7 B (Comparative Example 2) 11/AF 20/CF 95/AF 132/AF 12/AF 8/AF 8 C (Comparative Example 3) 10/AF 14/CF 110/AF 120/CF 13/AF 11/AF

(* CF: cohesive fracture, AF: adhesive fracture)

In the measurement experiments of Examples 1 to 5 and Comparative Examples 1 to 3, most of the adhesives in the examples showed a tendency for the failure mode of the CR surface and the Al surface to be in the CF state, and all physical properties for shear strength, impact strength and peel strength was able to obtain excellent test measurement results.

However, in the case of Comparative Examples 1 to 3, shear strength, peel strength, and impact strength showed a tendency to AF failure mode, and showed very weak results compared to Examples.

Having described specific parts of the present invention in detail above, it is clear that these specific techniques are merely preferred embodiments for those skilled in the art, and the scope of the present invention is not limited thereto. Accordingly, the substantial scope of the present invention will be defined by the appended claims and equivalents thereof. The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims (5)

a) 50 to 70% by weight of at least one epoxy resin, b) 15 to 25% by weight of an elastomeric toughening agent having terminal isocyanate groups in which core-shell rubber particles are dispersed, and c) 15 to 25% by weight of an additive. wealth; and
An epoxy-based structural adhesive composition comprising a; curing agent unit. According to claim 1,
The epoxy resin,
An epoxy-based structural adhesive composition comprising 30 to 40% by weight of a bisphenol-type epoxy resin and 20 to 30% by weight of a modified epoxy resin in which rubber particles are dispersed in the bisphenol-type epoxy resin. According to claim 1,
The toughening agent,
Diols of polybutadiene, polyethylene oxide (PEO), polytetramethylene oxide (PTMO), polypropylene oxide (PPO), polyisobutylene, poly(ethylene adipate) or polycaprolactone After dispersing core-shell rubber particles in one polyol or a mixture of two or more polyols selected from the group consisting of diol, triol, and tetraol, a polyisocyanate-based compound is added and reacted. To, an epoxy-based structural adhesive composition. According to claim 1,
The additive is
An epoxy-based structural adhesive composition, characterized in that at least one selected from the group consisting of a filler, a reactive diluent, an inorganic filler and a coupling agent. According to claim 1,
The subject part and the curing agent part,
1: characterized in that it is included in a weight ratio of (0.3 to 0.7), epoxy-based structural adhesive composition.