KR102411510B1 - Adhesive composition containing urethane modified epoxy compound and cured product prepared therefrom - Google Patents

Abstract

The adhesive composition containing the urethane-modified epoxy compound according to the present invention and its cured product have excellent compatibility with the epoxy resin, so that it is easy to handle, and excellent adhesive performance such as high shear strength and T-peel strength can be realized.
The adhesive composition of the present invention may be used as a structural adhesive. Specifically, it can be used as a structural adhesive in the assembly of vehicles, such as automobiles, aircraft, ships, etc., as well as structures such as civil engineering buildings. In particular, in response to the demand for adhesive materials for automobiles according to automobile weight reduction, it is possible to provide an adhesive composition containing the urethane-modified epoxy compound of the present invention having excellent adhesive performance and mechanical strength.

Description

Adhesive composition comprising a urethane-based modified epoxy compound and cured product prepared therefrom

The present invention relates to an adhesive composition comprising a urethane-based modified epoxy compound and a cured product prepared therefrom.

Epoxy resins used in adhesives are widely used in the bonding, molding, and coating industries due to their high mechanical properties and thermal and insulating properties. In spite of the good mechanical properties of the epoxy resin, it is pointed out as a major disadvantage in the industrial field requiring high resistance to impact due to brittleness, which is easy to break from impact, such as glass. That is, an epoxy resin lacking in toughness can compromise important strength requirements, such as impact strength, flexural strength, shear strength and peel strength. The epoxy adhesive composition whose strength requirements are damaged in this way has reduced adhesive performance and causes separation between the substrates, so that the field of use is inevitably limited.

In order to solve this problem, the recent epoxy adhesive composition is preparing an epoxy adhesive using an additive such as a toughening agent. However, these additives increase the viscosity of the adhesive or have low compatibility with the epoxy resin, making it difficult to handle, and there are problems in that the adhesive performance is deteriorated due to impact or compression shear at the bonding site. is in a minor state.

Therefore, there is still a need for research and development on adhesives that are easy to handle and that can realize excellent adhesive performance even under impact or high compression shear.

KR 10-2019-0096678 A (2019.08.20)

An object of the present invention is to provide an adhesive composition excellent in shear strength and T-peel strength.

In addition, it is an object of the present invention to produce a urethane-based modified epoxy compound with improved compatibility with the epoxy resin, and to directly participate in the curing reaction, thereby satisfying excellent mechanical strength and adhesive performance. It is to provide an adhesive composition comprising the and a cured product prepared therefrom.

In order to solve the above problems, the present invention provides an adhesive composition comprising an epoxy resin, a trifunctional urethane-modified epoxy compound represented by the following Chemical Formula 1, a toughening agent, and a filler.

[Formula 1]

In Formula 1, Y ₁ to Y ₆ are each independently C _2-4 alkylene;

Y ₇ is a substituted or unsubstituted hydrocarbon backbone, wherein at least one hydrogen is halogen, hydroxy, cyano, amino, carboxyl, carboxylate, C _1-20 alkyl, C _1-20 alkoxy, C ₂ - ₂₀ alkenyl, C _2-20 alkynyl, C _3-20 cycloalkyl, C _6-20 aryl, or a combination thereof; x+y+z ranges from 3 to 100.

According to an embodiment of the present invention, Y ₇ of Formula 1 may satisfy Formula 2 below.

[Formula 2]

At least one selected from L ₁ to L ₃ in Formula 2 is C _1-4 alkylene, and the other two are each independently a direct bond or C _1-4 alkylene;

R is hydrogen or C _1-7 alkyl.

According to an embodiment of the present invention, the adhesive composition is based on 100 parts by weight of the epoxy resin, 0.1 to 50 parts by weight of the trifunctional urethane-modified epoxy compound represented by Chemical Formula 1, 10 to 60 parts by weight of the toughening agent, and the filler 1 to 30 parts by weight.

According to an embodiment of the present invention, the toughening agent may be a urethane-based toughening agent, a rubber-based toughening agent, or a mixture thereof.

According to an embodiment of the present invention, the adhesive composition may further include a curing agent and a curing accelerator.

According to an embodiment of the present invention, the curing agent may be an amine-based curing agent, an acid anhydride-based curing agent, or a phenol-based curing agent.

According to an embodiment of the present invention, the adhesive composition may satisfy the following formula (1) upon thermal curing.

[Equation 1] S ₁ /S ₀ ≥ 1.1

In Formula 1, S ₁ is the shear strength (MPa) of a cured adhesive material containing a trifunctional urethane-modified epoxy compound represented by Formula 1, and S ₀ is a trifunctional urethane-based product represented by Formula 1 in the adhesive composition. Shear strength (MPa) of the cured adhesive excluding only the modified epoxy compound.

According to an embodiment of the present invention, the adhesive composition may satisfy Equation 2 below during thermal curing.

[Equation 2] T ₁ /T ₀ ≥ 1.1

In Formula 2, T ₁ is the T-peel strength (N/25 mm) of the cured adhesive containing the trifunctional urethane-modified epoxy compound represented by Formula 1, and T ₀ is represented by Formula 1 in the adhesive composition. It is the T-peel strength (N/25 mm) of the cured adhesive excluding only the trifunctional urethane-modified epoxy compound used.

An adhesive cured product obtained by curing the adhesive composition according to an embodiment of the present invention may be provided.

The adhesive composition comprising the trifunctional urethane-modified epoxy compound according to the present invention and the cured product prepared therefrom have excellent compatibility with the epoxy resin and thus not only easy handling, but also excellent adhesion such as high shear strength and T-peel strength performance can be implemented.

1 is a shear strength measurement result of the adhesive composition prepared according to Examples 1 to 4 and Comparative Example 1.
2 is a T-peel strength measurement result of the adhesive composition prepared according to Examples 1 to 4 and Comparative Example 1.

Hereinafter, an adhesive composition comprising a trifunctional urethane-modified epoxy compound according to the present invention and a cured product prepared therefrom will be described in detail. At this time, unless there are other definitions in the technical terms and scientific terms used, it has a meaning commonly understood by a person of ordinary skill in the art to which this invention belongs, and in the following description, it may unnecessarily obscure the subject matter of the present invention. A description of possible known functions and configurations will be omitted.

As used herein, the singular form may also be intended to include the plural form unless the context specifically dictates otherwise.

Numerical ranges as used herein include lower and upper limits and all values within that range, increments logically derived from the form and width of the range defined, all values defined therein, and the upper and lower limits of numerical ranges defined in different forms. all possible combinations of Unless otherwise defined in the specification of the present invention, values outside the numerical range that may occur due to experimental errors or rounding of values are also included in the defined numerical range.

As used herein, the term "comprises" is an open-ended description having an equivalent meaning to expressions such as "comprises", "contains", "has" or "characterized by", and is an element not listed further; Materials or processes are not excluded.

As used herein, the term “alkyl” refers to a monovalent organic radical derived from a saturated hydrocarbon.

As used herein, the term “alkenyl” refers to a monovalent organic radical derived from a straight-chain or pulverized hydrocarbon containing at least one double bond, and “alkynyl” refers to a straight-chain or pulverized form containing at least one triple bond. It refers to a monovalent organic radical derived from a hydrocarbon of

As used herein, the term “alkylene” refers to a divalent organic radical derived from a saturated hydrocarbon.

As used herein, the term "halogen" means a fluorine (F), chlorine (Cl), bromine (Br) or iodine (I) atom, "hydroxy" means -OH, "amino" means -NH ₂ , "cyano" means -CN, "carboxyl" means -COOH, and "carboxylate" means -COOM. M may be an alkali metal (Na, K, etc.).

As used herein, the term “alkoxy” refers to an —O-alkyl radical, where “alkyl” is as defined above.

As used herein, the term “cycloalkyl” refers to a monovalent free radical derived from a fully saturated or partially unsaturated hydrocarbon ring of 3 to 9 carbon atoms, and includes aryl or heteroaryl fused thereto.

As used herein, the term "aryl" means an aromatic ring monovalent organic radical derived from an aromatic hydrocarbon by removal of one hydrogen, suitably 4 to 7, preferably 5 or 6 ring atoms in each ring. It includes a single or fused ring system that includes, and includes a form in which a plurality of aryls are connected by a single bond.

As used herein, the term "epoxy resin" refers to an epoxy resin in a state that has been scientifically reacted with a curing agent, but as a component of an epoxy composition as commonly used in the technical field, it has at least one epoxy group as a functional group, so that the curing agent and may include an epoxy compound capable of reacting with. Representative examples include, but are not limited to, bisphenol A diglycidyl ether.

As used herein, the term “cured product” may be a cured product of an epoxy adhesive composition in a general sense. In addition, the cured product may include a semi-cured material.

Hereinafter, the present invention will be specifically described.

Conventional epoxy resins, despite excellent mechanical properties, are fragile like glass, and lack resistance to external impacts, that is, toughness. As a result of in-depth research on the epoxy 　 adhesive composition to overcome such problems, the present inventors developed an 　 adhesive composition containing a specific trifunctional urethane-modified epoxy compound with the epoxy 　 resin as the subject. The adhesive composition is not only easy to handle in a wide temperature range, but also has excellent mechanical properties such as shear strength and T-peel strength, and it has been found that excellent adhesive performance can be expressed even in impact or high compressive shear, thereby completing the present invention. .

The present invention may provide an adhesive composition comprising an epoxy resin, a trifunctional urethane-modified epoxy compound represented by the following Chemical Formula 1, a toughening agent, and a filler.

[Formula 1]

In Formula 1, Y ₁ to Y ₆ are each independently C _2-4 alkylene, Y ₇ is a substituted or unsubstituted hydrocarbon backbone, wherein at least one hydrogen is halogen, hydroxy, cyano, amino , carboxyl, carboxylate, C _1-20 alkyl, C _1-20 alkoxy, C _2-20 alkenyl, C _2-20 alkynyl, C _3-20 cycloalkyl, C _6-20 aryl or a combination thereof. , and x+y+z may range from 3 to 100.

Y ₇ of Formula 1 is a substituted or unsubstituted hydrocarbon backbone, wherein at least one hydrogen is halogen, hydroxy, C _1-20 alkyl, C _1-20 alkoxy, C _2-20 alkenyl, C It may be replaced with a substituent of _2-20 alkynyl, C _3-20 cycloalkyl, C _6-20 aryl, or a combination thereof. Specifically, Y ₇ of Formula 1 is C _1-20 alkyl, C _2-20 alkenyl, C _2-20 alkynyl, C _3-20 cycloalkyl, C _6-20 aryl, or a substituent of a combination thereof is substituted It may be a hydrocarbon backbone. More specifically, Y ₇ of Formula 1 is a substituent of C _1-7 alkyl, C _2-7 alkenyl, C _2-7 alkynyl, C _3-10 cycloalkyl, C _6-10 aryl, or a combination thereof. It may be a substituted hydrocarbon backbone.

In addition, in Formula 1, x, y and z are each independently an integer of 1 or more, and the sum thereof is 3 to 10, or 3 to 30, or 11 to 30, or 3 to 70, or 31 to 70, or It may be in the range of 3 to 90, or 71 to 90.

According to an embodiment of the present invention, Y ₇ of Formula 1 may satisfy Formula 2 below.

[Formula 2]

In Formula 2, at least one selected from L ₁ to L ₃ is C _1-4 alkylene, the other two are each independently a direct bond or C _1-4 alkylene, and R is hydrogen or C _1-7 alkyl.

In Formula 2, at least one selected from L ₁ to L ₃ may be methylene, ethylene, or propylene, and the other two may be each independently a direct bond, methylene, ethylene, or propylene, and R is hydrogen, methyl, ethyl or propyl, and the like.

Specifically, Chemical Formula 1 may be represented by Chemical Formula 3 below.

[Formula 3]

In Formula 3, x, y and z are each independently an integer of 1 or more, and the sum thereof is 3 to 10, or 3 to 30, or 11 to 30, or 3 to 70, or 31 to 70, or 3 to 90 , or may have a range of 71 to 90.

In addition, the trifunctional urethane-modified epoxy compound represented by Formula 1 is prepared by reacting a compound represented by Formula 4 with a compound represented by Formula 5 below, followed by further reaction with epichlorohydrin. it may be

Specifically, the amine group present at the terminal of the following Chemical Formula 4 may react with the compound represented by the following Chemical Formula 5 to form a poly(hydroxyurethane) structure having a hydroxyl group at the terminal. By adding epichlorohydrin thereto, a trifunctional urethane-based modified epoxy compound represented by Chemical Formula 1 can be prepared.

[Formula 4]

[Formula 5]

In Formula 4, R ₁ to R ₃ may be each independently C _2-4 alkylene, Y ₇ is a substituted or unsubstituted hydrocarbon backbone, wherein the substitution is at least one hydrogen is halogen, hydroxy, cyano, amino, carboxyl, carboxylate, C _1-20 alkyl, C _1-20 alkoxy, C _2-20 alkenyl, C _2-20 alkynyl, C _3-20 cycloalkyl, C _6-20 aryl or combinations thereof may be substituted with a substituent, and x+y+z may be in the range of 3 to 100. Specifically, Chemical Formula 4 may be Jeffamine T-403 or Jeffamine T-5000.

In Formula 5, R ₄ to R ₇ may be each independently hydrogen or C _1-3 alkyl. In this case, Chemical Formula 5 may be a cyclic carbonate compound, and more specifically, Chemical Formula 5 may be ethylene carbonate, propylene carbonate, butylene carbonate, or pentylene carbonate.

The epoxy equivalent weight (EEW) of the trifunctional urethane-modified epoxy compound may specifically satisfy the range of 200 to 350 g/eq, more specifically 230 to 300 g/eq, and when the above range is satisfied, the adhesive site Mechanical properties such as shear strength and T-peel strength and adhesion performance are improved, so more advantageous properties can be expressed.

The trifunctional urethane-based modified epoxy compound may have a weight average molecular weight of 200 to 5,000 g/mol. Specifically, it may be 400 to 3,000 g/mol or less, or 600 to 2,000 g/mol or less, or 700 to 1,000 g/mol or less, but is not limited thereto.

According to an embodiment of the present invention, the adhesive composition is based on 100 parts by weight of the epoxy resin, 0.1 to 50 parts by weight of the trifunctional urethane-modified epoxy compound represented by Chemical Formula 1, 10 to 60 parts by weight of the toughening agent, and the filler 1 to 30 parts by weight. Specifically, based on 100 parts by weight of the epoxy resin, 1 to 30 parts by weight of the trifunctional urethane-modified epoxy compound represented by Chemical Formula 1, 20 to 50 parts by weight of a toughening agent, and 5 to 20 parts by weight of a filler may be included, and more Specifically, with respect to 100 parts by weight of the epoxy resin, 1 to 20 parts by weight of the trifunctional urethane-modified epoxy compound represented by Chemical Formula 1, 20 to 50 parts by weight of a toughening agent, and 5 to 20 parts by weight of a filler. .

The epoxy resin may be used without limitation as long as it is conventionally used in the field. For example, any one or more bisphenol-type epoxy resins selected from bisphenol A, bisphenol E, bisphenol F, bisphenol M, bisphenol S and bisphenol H; and any one or a mixture of two or more selected from a glycidyl ether-based epoxy resin, a glycidyl amine-based epoxy resin, a phenol novolak-type epoxy resin, and a cresol novolak-type epoxy resin. Preferably, any one or two or more selected from the bisphenol A-based epoxy resin and the bisphenol F-based epoxy resin may be used in terms of maximally improving the adhesive performance, shear strength and T-peel strength.

In addition, the epoxy resin may be liquid at room temperature, and may have an epoxy equivalent weight (EEW) of 100 to 600 g/eq, or 150 to 550 g/eq. When the above range is satisfied, it may have more advantageous properties in that adhesive performance such as shear strength and T-peel strength to the bonding site is improved as well as the above-described effects.

According to an embodiment of the present invention, the toughening agent may be a urethane-based toughening agent, a rubber-based toughening agent, or a mixture thereof.

The urethane-based toughening agent may be used to increase the shear strength and T-peel strength of the adhesive composition of the present invention, and is not limited as long as it is commonly used in the relevant field. In addition, in order to effectively improve the impact strength and T-peel strength targeted in the present invention, specifically, for example, a polyol compound having a molecular weight of 1,000 to 3,000 g/mol and a polyisocyanate compound are reacted using a tin-based catalyst, , one prepared by capping with a phenol-based capping agent such as risocinol may be used. In this case, the polyol compound may be specifically polyether diol, and the polyisocyanate compound may be an alicyclic diisocyanate compound such as isophorone diisocyanate.

The rubber-based toughening agent may include rubber, a rubber copolymer, or a rubber derivative. Specific examples include butadiene rubbers such as terminal vinylized butadiene rubber, chlorinated butadiene rubber, chlorosulfonated butadiene rubber, nitrile butadiene rubber and styrene butadiene rubber; chlorosulfonated polyethylene; silicone rubber; rubber copolymers such as a styrene-butadiene-polymethylmethacrylate triblock copolymer, an acrylonitrile-butadiene-styrene copolymer, and a styrene-butadiene-styrene copolymer; or a rubber derivative, and the like, and any one or a mixture of two or more thereof may be used.

In addition, the rubber-based toughening agent may be a core-shell type rubber-based toughening agent. Specific examples include acrylic rubber, silicone rubber, urethane rubber, styrene-butadiene rubber, butadiene rubber, and the like. The core part and the shell part do not need to be the same type of rubber, and the core part is silicone rubber and the shell part is acrylic rubber, or the core part is butadiene rubber and the shell part is acrylic rubber. not available and available. In the preparation, it can be prepared by a well-known method, for example, emulsion polymerization, suspension polymerization, microsuspension polymerization, and the like. The core-shell type rubber-based toughening agent is preferably spherical. In addition, although not limited, the average particle diameter may be 0.01 to 20 μm, preferably 0.1 to 5 μm.

The toughening agent may be used in an amount of 10 to 60 parts by weight based on 100 parts by weight of the epoxy resin, preferably 20 to 50 parts by weight, more preferably 30 to 40 parts by weight, but if it does not impair the physical properties described in the present invention The content range is not particularly limited.

The filler may be used to improve mechanical strength, thermal dimensional stability and moisture resistance. Specifically, for example, quartz, limestone, mica, fumed silica, calcium carbonate, magnesium carbonate, aluminum nitride, boron nitride, silicon nitride, aluminum hydroxide, hydrotalcite, magnesium hydroxide, calcium hydroxide, wollastonite, bentonite, silica , any one selected from the group consisting of alumina, titanium oxide, barium sulfate, calcium sulfate, talc and glass fiber, or a mixture of two or more may be used. The filler may be used in 1 to 30 parts by weight based on 100 parts by weight of the epoxy resin, preferably 5 to 25 parts by weight, more preferably 5 to 20 parts by weight, but if it does not impair the physical properties described in the present invention The content range is not particularly limited.

According to an embodiment of the present invention, the adhesive composition may further include a curing agent and a curing accelerator. The curing agent is for curing the adhesive composition of the present invention, preferably a latent curing agent that is solid at room temperature to prepare a one-component adhesive, melts upon heating and reacts with the epoxy group. The curing agent may directly participate in the crosslinking of the composition or may be used in the form of a catalyst.

According to an embodiment of the present invention, the curing agent may be an amine-based curing agent, an acid anhydride-based curing agent, or a phenol-based curing agent. These may be used independently and may mix and use 2 or more types. Preferably, an amine-based curing agent may be used.

Examples of the amine-based curing agent include dimethyldisican, dicyandiamide, isophoronediamine, diethylenetriamine, triethylenetetramine, triethylenepentamine, bis(p-aminocyclohexyl)methane, methylenedianiline (eg , 4,4'-methylenedianiline, etc.), 4,7,10-trioxatridecane-1,13-diamine, polyetheramine (eg, Jeffamine D-230, Jeffamine D-400, etc.), diaminodi Phenylmethane, diaminodiphenylsulfone, 2,4-toluenediamine, 2,6-toluenediamine, 2,4-diamino-1-methylcyclohexane, 2,6-diamino-1-methylcyclohexane, 2 ,4-diamino-3,5-diethyltoluene, 2,6-diamino-3,5-diethyltoluene, 1,2-diaminobenzene, 1,3-diaminobenzene, 1,4-dia minobenzene, diaminodiphenyl oxide, 3,3',5,5'-tetramethyl-4,4'-diaminobiphenyl and 3,3'-dimethyl-4,4'-diaminodiphenyl, etc. Any one or two or more selected may be used.

Examples of the acid anhydride-based curing agent include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylnadic anhydride, nadic anhydride, glutaric anhydride, methyl and any one or two or more selected from hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride.

Examples of the phenol-based curing agent include phenol resins such as formaldehyde condensed resol phenol resins, non-formaldehyde condensed phenol resins, novolak phenol resins, novolak phenol formaldehyde resins, and polyhydroxystyrene resins; resol-type phenol resins such as aniline-modified resol resins and melamine-modified resol resins; novolak-type phenolic resins such as phenol novolac resins, cresol novolac resins, tert-butylphenol novolac resins, nonylphenol novolak resins and naphthol novolac resins; special phenol resins such as dicyclopentadiene-modified phenolic resins, terpene-modified phenolic resins, triphenolmethane-type resins, phenolaralkyl resins having a phenylene skeleton or diphenylene skeleton, and naphtholaralkyl resins; and any one or two or more selected from polyhydroxystyrene resins such as poly(p-hydroxystyrene).

The content of the curing agent may include 1 to 20 parts by weight of the curing agent, preferably 5 to 15 parts by weight, based on 100 parts by weight of the epoxy resin, but is not limited thereto.

The curing accelerator is used together with the curing agent to control the curing rate, and may be any one or two or more selected from a tertiary amine curing accelerator, an imidazole-based curing accelerator, and a urea-based curing accelerator, but is not limited thereto. .

Examples of the tertiary amine-based curing accelerator include any one or two or more selected from benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol or tri(dimethylaminomethyl)phenol.

Examples of the imidazole-based curing accelerator include 2-methyl imidazole, 2-heptadecyl imidazole, 2-phenyl imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-Ethyl-4-methylimidazole, 2-methylimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2 ,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, 2-undecylimidazole, 3-heptadecylimidazole, 2-phenyl imidazole, 2-phenylimidazoline, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole and any one or two or more selected from 1-cyanoethyl-2-undecylimidazole and the like.

Examples of the urea-based curing accelerator include any one selected from p-chlorophenyl-N,N-dimethylurea, 3-phenyl-1,1-dimethylurea, and 3,4-dichlorophenyl-N,N-dimethylurea; Two or more may be mentioned.

The curing accelerator may be used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the epoxy resin, more preferably 0.01 to 5 parts by weight, and still more preferably 0.5 to 3 parts by weight. Although it is good that sufficient hardening acceleration effect can be expressed in the said range, if the physical property described by this invention is not impaired, it is not restrict|limited in particular.

In addition to this, one or more other additives may be optionally added to the adhesive composition according to an embodiment of the present invention. For example, optional additives may include stabilizers, viscosity modifiers, surfactants, pigments or dyes, matting agents, flame retardants, curing inhibitors, defoamers, wetting agents, colorants, thermoplastics, processing aids, ultraviolet (UV) blocking agents, fluorescent compounds, UV stabilizers, antioxidants, mold release agents, and mixtures thereof may be further included. The optional additives may be used in a range that does not impair the physical properties of the adhesive composition of the present invention.

According to an embodiment of the present invention, the adhesive composition may satisfy Equation 1 below during thermal curing.

[Equation 1] S ₁ /S ₀ ≥ 1.1

In Formula 1, S ₁ is the shear strength (MPa) of a cured adhesive product containing a trifunctional urethane-modified epoxy compound represented by Formula 1, and S ₀ is a trifunctional urethane-based product represented by Formula 1 in the adhesive composition. Shear strength (MPa) of the cured adhesive excluding only the modified epoxy compound.

In Formula 1, the shear strength (MPa) of the cured adhesive product containing the trifunctional urethane-modified epoxy compound represented by Formula 1 is 10 compared to the shear strength (MPa) of the cured adhesive product excluding only the trifunctional urethane-modified epoxy compound % or more, it means that the effect can be improved. Preferably, Equation 1 may satisfy 1.2 or more. That is, an effect of improving by 20% or more can be expressed.

According to an embodiment of the present invention, the adhesive composition may satisfy Equation 2 below during thermal curing.

[Equation 2] T ₁ /T ₀ ≥ 1.1

In Formula 2, T ₁ is the T-peel strength (N/25 mm) of the cured adhesive containing the trifunctional urethane-modified epoxy compound represented by Formula 1, and T ₀ is represented by Formula 1 in the adhesive composition. It is the T-peel strength (N/25 mm) of the cured adhesive excluding only the trifunctional urethane-modified epoxy compound used.

In Formula 2, the T-peel strength (N/25 mm) of the cured adhesive product containing the trifunctional urethane-modified epoxy compound represented by Formula 1 is the T-peel of the cured adhesive except for the trifunctional urethane-modified epoxy compound. It means that the effect can be improved by 10% or more compared to the strength (N/25mm). Preferably, Equation 2 may satisfy 1.15 or more.

In addition, the adhesive composition may be a one-component type. In this case, since the pot life is long and the strength of the epoxy after curing is high, it may be useful as an epoxy adhesive for applications requiring high strength.

The adhesive composition of the present invention can be used as a structural adhesive. Specifically, it can be used as a structural adhesive in the assembly of vehicles, such as automobiles, aircraft, ships, etc., as well as structures such as civil buildings. In particular, in response to the demand for adhesive materials for automobiles according to automobile weight reduction, it is possible to provide an adhesive composition comprising the trifunctional urethane-modified epoxy compound of the present invention having excellent adhesive performance and mechanical strength. In addition, it exhibits excellent adhesion performance even between the same or different substrates, such as metal and metal, metal and glass, and metal and carbon fiber, and does not peel off between substrates even under strong shear stress. It is possible.

An adhesive cured product obtained by curing the adhesive composition according to an embodiment of the present invention may be provided. The curing may be thermosetting, and in the thermal curing process, the curing temperature and curing time of the process may be variously set according to the conditions of the curing agent, curing accelerator, and specimen, etc., but as long as it does not impair the physical properties described in the present invention it's not going to be Although the cured product contains a toughening agent, it has excellent mechanical strength, so that peeling between substrates does not occur easily, and excellent adhesion performance can be exhibited.

Hereinafter, an adhesive composition comprising a urethane-based modified epoxy compound according to the present invention will be described in more detail through Examples. However, the following examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms. Also, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, the terminology used in the description in the present invention is only for effectively describing specific embodiments, and is not intended to limit the present invention.

[Method for evaluating physical properties]

1) Shear strength evaluation (Shear strength, ㎫): The shear strength test piece forms an adhesive part of 25 Х 12.7 ㎜ on two metal steel plates (SPRC440, 25 Х 100 Х 1.6 ㎜) and overlaps each other with a 2 mm glass bead. After adjusting the thickness, it was prepared by curing at 180° C. for 20 minutes. Shear strength was measured by pulling the adherend at a speed of 1.3 mm/min according to ASTM D-1002 standard with a universal testing machine (UTM, universal testing machine).

2) T-peel strength evaluation (T-peel strength, N/25㎜): For the T-peel strength test piece, two metal steel plates (SPRC440, 25 Х 305 mm) were used to prepare the specimen according to ISO 11339 standard. The thickness of the bonding site was controlled with a 2 mm glass bead, and the specimen was prepared by curing at 180° C. for 20 minutes. T-peel strength was measured by pulling the adherend at a speed of 50 mm/min with a universal testing machine (UTM, universal testing machine).

[Preparation Example 1] Preparation of trifunctional urethane-modified epoxy compound (UME)

After putting 191.4 g of propylene carbonate and 250.0 g of Jeffamine T-403 in a round flask, the mixture was stirred at 100 degrees Celsius for about 5 days. And after fractionation using water and dichloromethane (DCM), the collected organic solvent layer was dried using MgSO ₄ and the residual solvent was evaporated to finally obtain 415.1 g (94%) of the product PHU in a brown liquid form. obtained.

Then, 154.9 g of PHU, 85.1 g of NaOH, and 196.8 g of epichlorohydrin were added to a round flask and stirred for about 15 minutes. Then, after adding 2.24 g of tetrabutylammonium bromide, the mixture was stirred at 50 degrees Celsius for about 4 hours. After the reaction was filtered through a filter, the filtered liquid was fractionally extracted using water and DCM. Then, the collected organic solvent layer was dried using MgSO ₄ and the residual solvent was evaporated to finally obtain 132.0 g (69.2%) of a liquid UME product with high brown viscosity.

The urethane compound obtained by the above method was analyzed through ¹ H NMR, and three protons located in the epoxy ring were identified at 2.5 to 3.3 ppm, respectively, and based on the newly generated peak at 910 cm ^-1 through FT-IR, By confirming that the epoxy structure was added, the preparation of the final product UME was confirmed.

The theoretical epoxy equivalent weight (EEW _theoret ) of the UME obtained by the above method is 298.69 to 318.05 g/eq (functionality of epoxy = 3), and the epoxy equivalent weight (EEW _exp. ) measured by ASTM D1652 is 265.88 g/eq (functionality of epoxy = 3.37 to 3.59). In addition, the weight average molecular weight of UME was predicted to be 787.86 to 889.89 Da (g/mol) based on the ¹ H NMR and epoxy equivalent weight (EEWexp.) results.

[Examples 1 to 4 and Comparative Examples 1 to 2]

An adhesive composition was prepared with the composition shown in Table 1 below, wherein the content of each component was described in units of parts by weight with respect to the epoxy resin. That is, the composition shown in Table 1 was added to a planetary mixer and stirred at room temperature for 30 minutes under vacuum conditions to prepare an adhesive composition. In addition, the results of the physical properties through the evaluation method are shown in FIGS. 1 and 2 below.

(parts by weight) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 EPIKOTE 828 100 100 100 100 100 100 UME 5 10 15 20 - - toughener 37.41 37.41 37.41 37.41 37.41 46.5 DICY 10.93 11.25 11.55 11.86 10.61 10.61 filler 9.09 9.09 9.09 9.09 9.09 - reaction accelerator 1.6 1.6 1.6 1.6 1.6 1.6

In Table 1, as the epoxy resin, MOMENTIVE's EPIKOTE 828 (epoxy equivalent weight: 187 g/eq) was used, and the toughening agent was a urethane-based toughening agent (80 g of polytetrahydrofuran having a number average molecular weight of 2000 g/mol and isophorone). 10 g of diisocyanate was reacted at 80° C. for 30 minutes using a dibutyltin dilaurate catalyst, and then 20 g of lysocinol was added to react) and a core-shell rubber toughener (MX-156, manufactured by KANEKA) was used by mixing in a 1:1 weight ratio. Dicyandiamide (DICY) (active hydrogen equivalent weight (AHEW) = 21 g/eq) of AIR PRODUCTS was used as the curing agent, and a mixture of limestone and quartz in a 1:1 weight ratio was used as the filler, and the curing accelerator was 3-phenyl-1,1-dimethylurea was used.

1 and 2, in the case of Example 2 in which 10 phr of a trifunctional urethane-modified epoxy compound (UME) was added in the adhesive composition according to the present invention, the highest shear strength (26.12 MPa) and T - Peeling strength (192.55 N/25mm) is shown, and compared to the shear strength (21.1 MPa) and T-peel strength (163.94 N/25mm) of Comparative Example 1 without UME added, the adhesion performance is improved by 24% and 17%, respectively. indicated. In addition, in the case of Comparative Example 2 in which the UME and the filler were removed, the shear strength and T-peel strength were insufficient as compared to Examples 1 and 1, and cracking occurred.

Through this, it was confirmed that the adhesive composition including the trifunctional urethane-modified epoxy compound, toughening agent and filler according to the present invention can exhibit excellent shear strength and T-peel strength. The adhesive composition can be widely used not only for adhesives but also for coatings and molding material parts, and in particular, it can be used for automotive adhesives and coating materials to be variously applied to the automotive adhesive material market for the purpose of weight reduction.

As described above, in the present invention, specific matters and limited examples and comparative examples have been described, but these are only provided to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and the present invention is not limited to the above examples. Various modifications and variations are possible from these descriptions by those of ordinary skill in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all those with equivalent or equivalent modifications to the claims will be said to belong to the scope of the spirit of the present invention. .

Claims (9)

An adhesive composition comprising an epoxy resin, a trifunctional urethane-modified epoxy compound represented by the following Chemical Formula 1, a toughening agent, and a filler.
[Formula 1]

In Formula 1,
Y ₁ to Y ₆ are each independently C _2-4 alkylene;
Y ₇ is a substituted or unsubstituted hydrocarbon backbone, wherein at least one hydrogen is halogen, hydroxy, cyano, amino, carboxyl, carboxylate, C _1-20 alkyl, C _1-20 alkoxy, C ₂ - ₂₀ alkenyl, C _2-20 alkynyl, C _3-20 cycloalkyl, C _6-20 aryl, or a combination thereof;
x+y+z ranges from 3 to 100. The method of claim 1,
The Y ₇ of Formula 1 is an adhesive composition that satisfies Formula 2 below.
[Formula 2]

In Formula 2,
At least one selected from L ₁ to L ₃ is C _1-4 alkylene, and the other two are each independently a direct bond or C _1-4 alkylene;
R is hydrogen or C _1-7 alkyl. The method of claim 1,
The adhesive composition is based on 100 parts by weight of the epoxy resin, 0.1 to 50 parts by weight of the trifunctional urethane-modified epoxy compound represented by Chemical Formula 1, 10 to 60 parts by weight of a toughening agent, and 1 to 30 parts by weight of a filler Adhesive composition comprising. The method of claim 1,
The toughening agent is a urethane-based toughening agent, a rubber-based toughening agent, or a mixture thereof. The method of claim 1,
The adhesive composition further comprises a curing agent and a curing accelerator. 6. The method of claim 5,
The curing agent is an amine-based curing agent, an acid anhydride-based curing agent, or a phenol-based curing agent curing agent adhesive composition. The method of claim 1,
When the adhesive composition is thermally cured, the adhesive composition that satisfies Formula 1 below.
[Equation 1] S ₁ /S ₀ ≥ 1.1
In Formula 1, S ₁ is the shear strength (MPa) of a cured adhesive material containing a trifunctional urethane-modified epoxy compound represented by Formula 1, and S ₀ is a trifunctional urethane-based product represented by Formula 1 in the adhesive composition. Shear strength (MPa) of the cured adhesive excluding only the modified epoxy compound. The method of claim 1,
When the adhesive composition is thermally cured, the adhesive composition that satisfies Formula 2 below.
[Equation 2] T ₁ /T ₀ ≥ 1.1
(In Formula 2, T ₁ is the T-peel strength (N/25 mm) of the cured adhesive material containing the trifunctional urethane-modified epoxy compound represented by Formula 1, and T ₀ is Formula 1 in the adhesive composition. T-peel strength (N/25 mm) of the cured adhesive excluding only the indicated trifunctional urethane-modified epoxy compound.) A cured product obtained by curing the adhesive composition of any one of claims 1 to 8.

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