KR101991797B1 - One-pack type epoxy adhesive composition with curing agent of polythiol copolymer and curing catalyst of core-shell - Google Patents

Abstract

The present invention relates to a one-component epoxy adhesive composition comprising an epoxy resin, a curing agent of a polythiol copolymer structure and a latent curing catalyst of a core shell structure. More particularly, the present invention relates to a one-component epoxy adhesive composition comprising a polythiol copolymer curing agent formed by polymerization of a monomer having a thiol group monomer and a functional group capable of controlling reactivity or physical properties in an inorganic silane main chain and a core- . Therefore, the one-part type epoxy adhesive composition does not cause odor peculiar to sulfur, can realize various properties, and has an advantage of excellent storage stability.

Description

TECHNICAL FIELD [0001] The present invention relates to a one-pack type epoxy adhesive composition comprising a polythiol copolymer curing agent and a core shell latent curing catalyst,

The present invention relates to a one-component epoxy adhesive composition comprising a curing agent of a polythiol copolymer structure and a latent curing catalyst of a core shell structure. More particularly, it relates to a polythiol copolymer curing agent formed by polymerization of a monomer having a thiol group monomer and a functional group capable of controlling reactivity or physical properties in an inorganic silane main chain and a core shell latent curing catalyst in which a curing reaction takes place when a predetermined energy is applied Based epoxy adhesive composition.

The epoxy resin has excellent physical properties such as adhesiveness to various substrates, heat resistance, chemical resistance, electrical characteristics and mechanical characteristics when compared with other resins, and it is easy to control physical properties and is used in various industrial fields such as civil engineering and construction adhesives have. Epoxies are not used alone but are used after being cured with a prepolymer of a thermosetting resin by reaction with a curing agent. At this time, the epoxy forms a three-dimensional network structure of an insoluble and infusible net type, and exhibits inherent properties. Epoxies must contain at least two Epoxide rings in order to form a three-dimensional network structure in the form of a net.

The curing agents for epoxy resins are largely divided into amine type, acid anhydride type, isocyanate type and mercaptan type depending on the kind of the material, but they are generally used in combination to control the curing behavior of the adhesive.

Although many conventional epoxy resin curing agents have been developed, curing catalysts are used together to promote the curing reaction. There is a demand for a catalyst having a low temperature curability that enables curing even at a low temperature for the purpose of improving the productivity depending on the application in which the epoxy resin is used. Further, there is a demand for a curing catalyst having a high storage stability, which promotes curing only when a desired curing temperature is achieved for the purpose of improving handling during storage of the cages, and has no curing catalyst activity when the curing temperature is not a desired curing temperature.

In general, the epoxy adhesive is a thermosetting resin-based adhesive containing epoxy resin, curing agent and catalyst as typical components and further containing additives such as fillers or diluents. The epoxy resin is excellent in mechanical properties after curing, has a strong adhesive force, and has an advantage of excellent heat resistance and electrical insulation. As a result, it is used for repairing cracks in concrete and for bonding metals. Epoxy adhesives can be cured even at room temperature and have little or no ancillary products in the reaction, and they are widely used in general industrial fields such as home, industrial, construction, electric, automobile, and aircraft. In particular, epoxy adhesives may be suitable for applications where durability is required.

In general, epoxy adhesives are divided into two types, liquid or single-liquid, depending on the type of storage. The liquid epoxy adhesive is mixed with an epoxy resin and a curing agent in an appropriate amount immediately before use, and the one-part epoxy adhesive is stored in a state in which the epoxy resin and the curing agent are mixed and can be used immediately without further processing.

This liquid type epoxy adhesive is difficult to be stored and handled, there is a possibility of metering error, and the efficiency of the work is deteriorated. Therefore, a one-component epoxy adhesive in which an epoxy resin and a hardener are mixed in advance is preferred. The one-part epoxy adhesive is cured by progressing the crosslinking reaction through heating, and usually requires a temperature of 120 ° C or higher. However, the above curing conditions are liable to damage the temperature-sensitive device, particularly the adherend in the electronic device, and thus it is difficult to use the product in a specific product. In addition, when an epoxy adhesive is used for an electronic device, thermal deformation of the adhered portion may occur due to heat generated by the driving of the electronic device, thereby causing a problem that the performance of the device is deteriorated. Securing high heat resistance and high reliability is an important factor.

In general, when the curing temperature of the epoxy adhesive is lowered, the curing time is greatly increased. In some cases, it is difficult to achieve complete curing. Further, since an increase in curing time leads to an increase in the production time, It is required to develop a low-temperature-curing epoxy adhesive capable of lowering the curing temperature.

Therefore, it is known to use a curing agent containing a thiol group in order to improve the low temperature fast curing property. However, the curing agent containing a thiol group used in known techniques has difficulties in application due to the characteristic odor of sulfur.

In this connection, Korean Patent No. 10-0951645 (entitled "Low Temperature-Curing Epoxy Curing Agent, Epoxy Paint Composition Including the Same, and Method of Formating Coating Film Using the Same" hereinafter, referred to as Prior Art 1) And a polythiol resin prepared by reacting a polythiol containing a carboxyl group and an anhydride of a carboxylic acid in a molar ratio of 1: 0.5 to 1: 0.7, discloses a technique relating to an epoxy curing agent, There is an advantage that the addition of a solvent for viscosity control is not required and the low temperature curability and water resistance can be improved.

However, the polythiol for epoxy curing in the prior art 1 has a problem that the odor of the sulfur contained in the thiol group is insufficient to remove the odor, and a disadvantage that various additives are required in order to secure the same properties at high temperature curing conditions under low temperature curing conditions there was.

On the other hand, a one-component type epoxy adhesive is essentially used as a latent curing agent which induces a curing reaction only when a curing reaction does not occur at room temperature and only a predetermined stimulus such as heat is given. For this purpose, a method of encapsulating a hardener has been widely used. The capsule type latent curing catalyst does not affect the curing characteristics of the curing agent by the protective film, and the effect of enhancing the storage stability of the caking liquid can be expected.

Generally, as a method of forming a protective film on the surface of a curing agent, a method of dissolving isocyanate or epoxy in an organic solvent, dispersing the amine-based adhesive thereon, and applying heat to induce a reaction on the surface of the adhesive are widely known EP 0304503, EP 1852452). However, such a wet process requires a filtration and drying process, requires additional cost and time for using and treating a large amount of organic solvent, and is disadvantageous in that it is not environmentally friendly.

Therefore, there is a demand for development of a thiol group-containing curing agent capable of forming an epoxy network structure with high physical properties without inducing odor peculiar to sulfur while allowing low-temperature curing. In addition, there is a need to develop a latent curing catalyst for increasing the pot life of the latent curing catalyst used in the one-component epoxy resin and the storage stability of the composition after the tank liquid.

Korean Patent No. 10-0951645 European Patent No. 0304503 European Patent No. 1852452

SUMMARY OF THE INVENTION The present invention provides a technique for a one-component epoxy adhesive composition comprising a core-shell structure latent curing catalyst prepared without the use of a copolymer curing agent and a solvent and additives for monomers functionalized with multifunctional functional groups do.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. There will be.

According to an aspect of the present invention, there is provided a latent curing catalyst comprising an epoxy resin, a curing agent of a polythiol copolymer structure, and a core shell structure, wherein the polythiol copolymer structure comprises a thiol a first repeating unit comprising a monomer having a thiol functional group and a curing accelerating functional group capable of controlling the curing behavior of the monomer and the adhesive and a second repeating unit containing a functional group capable of controlling the reactivity or physical properties of the adhesive And at least one kind of repeating unit selected from the group consisting of the epoxy resin and the epoxy resin.

In an embodiment of the present invention, the epoxy resin may be a one-component epoxy adhesive composition characterized by containing a commercialized epoxy resin containing bisphenol A or bisphenol F as a main component.

In an embodiment of the present invention, the latent curing catalyst content of the core shell structure is 1 wt% to 5 wt% of the epoxy resin content.

In one embodiment of the present invention, the first repeating unit is formed by polymerization of a monomer functionalized with at least one monomer and a functional group capable of controlling the curing behavior of the adhesive. have.

In the embodiment of the present invention, the functional groups capable of controlling the curing behavior of the monomer and the adhesive are selected from a primary amine group, a secondary amine group, a tertiary amine group, a carboxyl group, a hydroxyl group and derivatives thereof Or one or more curing accelerating functional groups.

In an embodiment of the present invention, the second repeating unit may be a one-component epoxy adhesive composition characterized by polymerization of a monomer functionalized with a functional group capable of controlling the reactivity or physical properties of at least one adhesive .

In the embodiment of the present invention, the functional group capable of controlling the reactivity or physical properties of the adhesive includes at least one selected from a hydroxyl group, an epoxy group, an aliphatic hydrocarbon group, a cyanogen group, an imidazole group, and derivatives thereof Lt; RTI ID = 0.0 > epoxy < / RTI >

In the exemplary embodiment of the present invention, when the latent curing predetermined energy is applied, the surface of the catalyst reacts to accelerate the curing reaction by the internal material.

In an embodiment of the present invention, the latent curing catalyst of the core shell structure comprises a core containing a curing agent material, a protective film formed on the surface of the curing agent core, and a filling material physically chemically bonded to the protective film by mechanofusion Lt; RTI ID = 0.0 > epoxy < / RTI > adhesive composition.

In one embodiment of the present invention, the curing agent includes at least one selected from the group consisting of an amine-based adduct, a dicyandiamide-based material, a dihydride compound, and a dichlorophenyldimethylurea compound. Epoxy adhesive composition.

In one embodiment of the present invention, the protective film may be an isocyanate compound.

In an embodiment of the present invention, the filled particles are selected from the group consisting of polystyrene, polymethyl methacrylate, polyvinyl acetate, ethylene-vinyl acetate copolymer, acrylate, acryl-ester copolymer, styrene, styrene- Silver, copper, gold, palladium, platinum, nickel, aluminum, lead, zinc, metal alloys, indium tin oxide, silver oxide, gold or silver But are not limited to, coated nickel, silver coated nickel, silver coated copper, silver coated aluminum, metal coated glass spheres, metal coated fillers, metal coated polymers, silver coated fibers, silver coated spheres, antimony doped tin oxides, Conductive nanospheres, carbon black, carbon fibers, graphite, and carbon nanotubes. Lt; RTI ID = 0.0 > epoxy < / RTI >

According to an embodiment of the present invention, it is possible to rapidly cure the epoxy adhesive at a low temperature (60 ° C to 90 ° C), including a polythiol formed by polymerization of monomers having at least one functional group with a thiol group having low- Provides a feature. Accordingly, the polythiol according to the present invention is advantageous in that it is easy to apply because the thiol group is bonded to the inorganic silane main chain and does not cause odor peculiar to sulfur.

The curing agent according to an embodiment of the present invention may further include at least one repeating unit selected from a first repeating unit having a polythiol and a curing accelerating functional group and a second repeating unit having a functional group capable of controlling physical properties of the adhesive It is advantageous in that properties of epoxy adhesive such as low temperature fast curing characteristics, securing stability at room temperature storage, ensuring heat resistance, and adhesion control can be variously implemented depending on the type and ratio of functional groups including units.

In addition, according to embodiments of the present invention, the surface activity and physical properties of the latent curing agent particles and the charged particles using the high mechanical energy of the dry high energy type mixer are controlled through the control of materials and process conditions without using solvents and additives do. Thereby having the advantage of physicochemically bonding the latent curing agent particles and the charged particles. This provides an advantage that the reaction efficiency can be improved in the process without supplying a heat source from the outside.

In addition, according to the embodiment of the present invention, the process is simpler and more environmentally friendly than the conventional wet process, the process time is short and the economical efficiency is improved, and the denseness of the protective film is increased to provide a storage stability.

As described above, the one-pack type epoxy curing agent composition according to the present invention provides stability at room temperature, curing at low temperatures, odor removal, and one-component advantage.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a one-part epoxy adhesive composition of the present invention. FIG.
2 is a schematic view illustrating a curing agent of a polythiol copolymer structure according to an embodiment of the present invention.
FIG. 3 is a view for explaining the formation of a polythiol in a chain form and a polythiol in a three-dimensional network structure by polymerization of a monomer containing a thiol group according to an embodiment of the present invention.
4 is a schematic diagram of a latent curing catalyst of a core shell structure according to an embodiment of the present invention.
5 is an IR spectrum of a curing agent and a monomer of a polythiol copolymer structure prepared according to an embodiment of the present invention.
6 is a graph showing the results of DSC analysis of polythiol, curing agent of polythiol copolymer structure according to Production Example 1 and Production Example 2;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when a part is referred to as being "connected" (connected, connected, coupled) with another part, it is not only the case where it is "directly connected" "Is included. Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a one-part epoxy adhesive composition of the present invention. FIG.

According to Fig. 1, the one-part epoxy adhesive composition may be composed of an epoxy resin, a curing agent and a curing catalyst.

According to one embodiment of the present invention, the epoxy resin may include but is not limited to a commercialized epoxy resin containing bisphenol A or bisphenol F as a main component. According to one embodiment of the present invention, the curing agent is a curing agent having a polythiol copolymer structure, and the curing catalyst may be a latent curing catalyst having a core shell structure.

According to an embodiment of the present invention, the latent curing catalyst content of the core shell structure may be 1 wt% to 5 wt% of the epoxy resin content. Typically, epoxy resin and curing agent compositions may be present in various compositions depending on physical properties and curing behavior. Further, the curing catalyst is based on the weight showing sufficient curing, and the weight of the curing catalyst is usually determined to be 5 wt% or less based on the epoxy resin.

2 is a view for explaining a curing agent of a polythiol copolymer structure in a one-part epoxy adhesive composition according to an embodiment of the present invention. As shown in the drawings, the present invention relates to a process for producing a polyurethane resin composition comprising a first repeating unit containing a polythiol formed by polymerization of a monomer containing a thiol group and a curing accelerating functional group, and a second repeating unit containing a functional group capable of controlling physical properties of the adhesive The present invention provides a one-pack type epoxy adhesive composition comprising at least one kind of repeating unit selected from the group consisting of epoxy,

Hereinafter, the present invention will be described in a manner in which the curing agent of the polythiol copolymer structure contained in the one-part epoxy adhesive composition of the present invention is repeatedly described in units of repeating units.

The one-part epoxy adhesive composition according to the present invention comprises a polythiol formed by polymerization of a monomer containing a thiol group to ensure low-temperature fast curing properties. The polythiol of the present invention may be formed by polymerization of a silane-based monomer containing at least one thiol group and includes those represented by the following general formula (1) or (2), but the structure of the polythiol is not limited thereto do. The polythiol of the present invention may be bonded to a backbone containing inorganic silane directly or via a hydrocarbon such as an alkyl group via a thiol group, There is an advantage that it does not. Conventionally, the thiol group-containing curing agent bonded to the hydrocarbon chain has been difficult to use due to malodor, but the curing agent of the present invention includes a polythiol formed by polymerization of a silane monomer containing a thiol group, .

(In the above formula (1) or (2)

L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,

And R is an alkyl group having between 1 and 10 carbons.)

The formula (1) is a polythiol group in the form of a chain, and the formula (2) is a polythiol group in a three-dimensional network structure, which will be described in detail below with reference to the drawings.

3 is a view for explaining the formation of a polythiol by polymerization of a monomer containing a thiol group. Referring to FIG. 3 (a), in one embodiment of the present invention, the polythiol group may be formed by polymerization of a trialkoxysilane monomer containing a thiol group (-SH), and in this case, Thereby forming a network-structured polymer. More specifically, a trialkoxysilane monomer containing a thiol group can form a polymer by a sol-gel reaction of a widely known alkoxysilane, which requires a catalyst (+ H) and distilled water (H ₂ O) in the reaction . (In Fig. 3 (a), R and R 'are C1 to C10 alkyl groups and n is an integer of 2 or more).

Referring to FIG. 3 (b), in another embodiment of the present invention, the polythiol group can form a polythiol polymer in a chain form by a sol-gel reaction of a dialkoxysilane containing a thiol group. In addition, the physical properties of the curing agent may vary in the case where the polymer is in the form of a chain and in the case of a three-dimensional network structure. For example, it is known that a polymer having a three-dimensional network structure has excellent heat resistance in comparison with a polymer in a chain form. It may therefore be desirable to select and polymerize monomers that exhibit properties more suitable for the physical properties required in the application. (In Fig. 3 (b), R and R 'are C1 to C10 alkyl groups and n is an integer of 2 or more).

In the above, referring to FIG. 3, a one-part epoxy adhesive of a polythiol copolymer structure formed by polymerization of a trialkoxysilane or dialkoxysilane monomer containing a thiol group has been described. However, It is obvious that the present invention can also be applied to a second repeating unit formed by polymerization of a monomer containing a first repeating unit formed by polymerization of an adhesive and a functional group capable of controlling the reactivity or physical properties of the adhesive.

The one-part epoxy adhesive composition of the present invention comprises a first repeating unit formed by polymerization of at least one or more functionalized monomers with a curing promoting functional group capable of promoting curing of the epoxy resin. In the present invention, the curing accelerating functional group is a group having a primary amine group (-NH ₂ ), a secondary amine group (-NHR), a tertiary amine group (-NRR '), a carboxyl group (-COOH) And a derivative thereof. These curing accelerating functional groups can catalyze the ring opening reaction of the epoxy rings included in the epoxy resin to accelerate the curing of the epoxy. Among them, the primary amine group, the secondary amine group and the carboxyl group have active hydrogen, May be possible.

When the one-part epoxy adhesive composition of the present invention contains the polythiol and the first repeating unit, the low temperature fast curing property of the thiol group is further improved, and complete curing can be performed quickly at a low temperature curing condition. The curing agent having such physical properties may be more suitable when it causes deformation and deterioration of the adherend due to heat.

The first repeating unit of the present invention formed by polymerization of at least one or more functionalized monomers with the curing accelerating functional group may include those represented by the following general formula (3) or (4). In one embodiment, the first repeating unit of the present invention may be formed by polymerization of a silane monomer functionalized with at least one curing accelerating functional group, as in the case of the polythiol represented by the above formula (1) or (2).

(In the above formula (3) or (4)

L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,

R is an alkyl group having between 1 and 10 carbons,

X is a cure accelerating functional group.)

However, the first recurring unit of the present invention is not limited to the above-mentioned general formula (3) or (4), and if the monomer having at least one functional group as a curing accelerating functional group is copolymerized with a monomer containing a thiol group, .

The first recurring unit of the present invention includes a case where two or more kinds of curing promoting functional groups are formed by polymerization of monomers having different curing promoting functional groups different from each other as shown in the following Formulas (3-1) and (4-1) do.

(In the formulas (3-1) and (4-1)

X ₁ and X ₂ represent different curing accelerating functional groups.)

There is a difference in the curing initiation temperature, curing rate, volatility characteristic or heat resistance of the curing agent depending on the curing promoting functional group, and in order to have the optimum physical properties required for a desired application field, a monomer functionalized with different curing promoting functional groups And that the first repeating unit having at least two or more curing accelerating functional groups can be included in the one-pack type epoxy curing agent composition of the present invention.

), 알리파틱 탄화수소기(

,

), 시안화기(-CN), 이미다졸기 및 이들의 유도체 중에서 선택되는 어느 하나 이상일 수 있다.The one-part epoxy adhesive composition of the present invention may contain a second repeating unit formed by polymerization of at least one functionalized monomer as a functional group capable of controlling the reactivity or physical properties of the adhesive. The functional groups capable of controlling the reactivity or physical properties of the adhesive include a hydroxyl group (-OH), an epoxy group (

), Aliphatic hydrocarbon group (

,

), A cyanogen (-CN) group, an imidazole group, and derivatives thereof.

In the present invention, the second repeating unit formed by the polymerization of the monomer functionalized with an epoxy group can improve the compatibility with the epoxy group to facilitate the preparation of the one-part epoxy adhesive composition and the handling of the adhesive, and the functionalization with the hydroxyl group The second repeating unit formed by the polymerization of the monomers may react with the epoxide of the epoxy resin to develop the crosslinked structure of the epoxy adhesive.

Further, the second repeating unit formed by polymerization of an aliphatic hydrocarbon group or a monomer functionalized with a cyanation group can delay the curing of the epoxy resin, thereby lowering the reaction rate of the one-part epoxy adhesive and improving stability at room temperature and storage stability Can be done.

In addition, when it contains a second repeating unit formed by polymerization of a monomer functionalized with an imidazole group, it may be possible to secure the potential curing properties of the epoxy adhesive. The imidazole compound does not undergo a curing reaction when stored at room temperature and has a property of causing a curing reaction by light irradiation or heating so that when the imidazole compound contains a repeating unit formed by polymerizing a functionalized monomer, Can be secured.

The second repeating unit of the present invention formed by polymerization of at least one or more functionalized monomers as a functional group capable of controlling the reactivity or physical properties of the one-component epoxy adhesive composition may include those represented by the following general formula (5) or have.

(In the above Chemical Formula 5 or Chemical Formula 6,

L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,

R is an alkyl group having between 1 and 10 carbons,

Y is a functional group capable of controlling the reactivity or physical properties of the adhesive.)

However, the second repeating unit of the present invention is not limited to the above-mentioned formula (5) or (6). If the functional group capable of controlling the reactivity or physical properties of the one-part epoxy adhesive composition is a monomer having at least one functional group, It is stated that any amount of copolymerization with monomers can lead to the present invention.

The second repeating unit of the present invention includes a case in which two or more kinds of reactive or physical property controlling functional groups are formed by polymerization of monomers having at least one or more functional groups with different kinds of reactive or physical property controlling functional groups. In this case, the second repeating unit may be represented by the following general formula (5-1) or (6-1), but it is not limited thereto and it may be possible to have two or more kinds of reactive or physical property- .

(In the formulas (5-1) and (6-1)

Y ₁ and Y ₂ are functional groups capable of controlling the reactivity or physical properties of the adhesive, and Y ₁ and Y ₂ are different from each other.

The one-part epoxy adhesive composition according to the present invention may include various combinations including a polythiol and at least one repeating unit selected from a first repeating unit and a second repeating unit. Specifically, the one-part epoxy adhesive composition of the present invention may include, but is not limited to, a curing agent of the polythiol copolymer structure represented by the following formula (7), (8), (9), (10)

The one-part epoxy adhesive compositions represented by the following general formulas (7) and (8) may include a curing agent of a polythiol copolymer structure formed by copolymerization of a monomer containing a thiol group and a monomer functionalized with a curing accelerating functional group (X).

(In the above formula (7) or (8)

L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,

R is an alkyl group having between 1 and 10 carbons,

X is a cure accelerating functional group,

i and j are each independently an integer of 1 or more.

The one-part epoxy adhesive compositions represented by the following general formulas (9) and (10) are prepared by copolymerizing monomers containing a thiol group and a polythiol copolymer structure formed by copolymerization of monomers functionalized with a functional group (Y) A curing agent.

(In the above formula (9) or (10)

L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,

R is an alkyl group having between 1 and 10 carbons,

Y is a functional group capable of controlling the reactivity or physical properties of the adhesive,

and l and m are each independently an integer of 1 or more.

The one-part epoxy adhesive compositions represented by the following formulas (11) and (12) are formed by copolymerization of monomers functionalized with a functional group capable of controlling the reactivity or physical properties of a monomer containing a thiol group, a monomer functionalized with a curing- Copolymers.

(In the above formula (11) or (12)

L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,

R is an alkyl group having between 1 and 10 carbons,

X is a cure accelerating functional group,

Y is a functional group capable of controlling the reactivity or physical properties of the adhesive,

a, b, and c are each independently an integer of 1 or more.

As shown in the above formulas (7) to (12), the present invention can be used in various combinations by copolymerizing monomers containing a thiol group, at least one monomer selected from monomers functionalized with a functional group capable of controlling physical properties of an epoxy curing agent and an epoxy adhesive, Based epoxy adhesive composition containing a curing agent of a thiol-copolymer structure can be formed, whereby the physical properties of the curing agent can be variously controlled. However, the one-part epoxy adhesive composition according to the present invention is not limited to the above-mentioned formulas.

The one-part epoxy adhesive composition of the present invention may be in the form of a random copolymer, an alternative copolymer, a block copolymer, a graft copolymer and a star block copolymer (star-shaped copolymer).

In the present invention, the molecular weight of the curing agent of the polythiol copolymer structure in the one-part epoxy adhesive composition is not particularly limited, and may be adjusted depending on the application field of the one-part epoxy adhesive composition. In one embodiment, the one-part epoxy adhesive composition for bonding the LED lens requires low viscosity properties, and thus it may be desirable to control the molecular weight of the curing agent from 1000 g / mol to 3000 g / mol. However, it should be understood that the present invention is not limited thereto. However, as the molecular weight of the polymer of the one-part epoxy adhesive composition increases, the viscosity tends to increase. When the viscosity is excessively increased, the handling of the adhesive may not be easy. Therefore, It may be preferable to control the molecular weight of the copolymer.

Hereinafter, the latent curing catalyst included in the one-part epoxy adhesive composition of the present invention will be described.

The latent curing catalyst is a catalyst for solving the drawbacks of the liquid epoxy resin composition and does not undergo a curing reaction under ordinary conditions and undergoes a curing reaction by light irradiation or heating.

4 is a schematic diagram of a latent curing catalyst of a core shell structure according to an embodiment of the present invention.

Referring to FIG. 4, the latent curing catalyst of the core shell structure is a structure that avoids direct contact with the epoxy resin, and shows a form in which the particulate curing catalyst is surrounded by the charged particles using a dry coating. The latent curing catalyst may have structural characteristics that confer latency in the curing reaction and allow it to collapse at a predetermined temperature to initiate curing. The filler particles that control the latent curing catalyst potential and cure behavior may be chemically treated fine powdered silica.

Hereinafter, a method for preparing the latent curing catalyst according to an embodiment of the present invention will be described.

Hereinafter, Preparation Examples and Experimental Examples of the present invention will be described. However, these production examples and experimental examples are intended to explain the constitution and effects of the present invention more specifically, and the scope of the present invention is not limited thereto.

[Production Example 1]

Thiol group  And a hardening promoting functional group (-OH) Polythiol  Synthesis of curing agent of copolymer structure

A silane monomer containing a thiol functional group and a silane monomer containing a hydroxyl group (-OH) as a curing accelerating functional group were mixed at a weight ratio of 9: 1, 3 g of ethanol as a solvent was added, stirred for 10 minutes, Respectively. 100 μl of acid catalyst (+ H) and 1 ml of distilled water were further added to the ultrasonic treated solution, and the mixture was stirred and sonicated for 10 minutes to hydrolyze the acid catalyst to synthesize a curing agent for the polythiol copolymer structure Respectively. After completion of the reaction, the reaction product was washed with 120 ml of ethanol to remove impurities such as remaining adducts, water, and solvents. The product was purified by an azeotropic process through evaporation, and the resulting product was repeated five times. Hour to obtain a curing agent (copolymerization ratio of 9: 1) of the purified polythiol copolymer structure.

[Production Example 2]

Thiol group  And a hardening promoting functional group (-OH) Polythiol  Synthesis of curing agent of copolymer structure

Except that a silane monomer containing a thiol functional group and a silane monomer containing a hydroxyl group (-OH) as a curing accelerating functional group were mixed at a weight ratio of 8: 2 in the same manner as in Preparation Example 1, (Copolymerization ratio of 8: 2) as a curing agent.

The curing agent of the polythiol copolymer structure prepared according to Production Example 1 and Production Example 2 is represented by the following formula (A). (The curing agent of the polythiol copolymer structure produced according to Production Example 1 and Production Example 2 is represented by the same formula, but the copolymerization ratio of the silane monomer containing a thiol functional group and the silane monomer containing a curing promoting functional group Are 9: 1 and 8: 2 respectively).

(A)

In order to confirm the synthesis of the curing agent of the polythiol copolymer structure, IR analysis of the curing agent according to Production Example 1 was carried out, and the spectrum obtained by IR analysis was shown in Fig. IR spectra of the monomers are also shown for comparison. (-SH) functional group and a hydroxyl group (-OH) bonded to the main chain of the silane can be confirmed by confirming the Si-O-Si peak, You can also check.

[Production Example 3]

One-pack type  Epoxy adhesive composition synthesis

A latent curing catalyst was added to a curing agent of an epoxy resin and a polythiol copolymer structure, and the mixture was mixed by a ball-mill process to prepare a one-part epoxy adhesive. The content of the latent curing catalyst was set to 1 wt%, 3 wt%, or 5 wt%, respectively, relative to the epoxy resin content, and the capacity was increased by 30 minutes or more using a planetary mixer .

[Comparative Example 1]

Polythiol  synthesis

10 g of the silane monomer containing a thiol functional group and 3 g of ethanol were mixed, stirred for 10 minutes, and sonicated for 30 minutes. After the addition of 100 μl of acid catalyst (+ H) and 1 ml of distilled water to the ultrasonically treated solution, a polymer of low molecular weight was synthesized by hydrolysis with acid catalyst by stirring and ultrasonic treatment for 10 minutes. After completion of the reaction, purification and drying were carried out in the same manner as in Preparation Example 1 and Preparation Example 2 to complete the synthesis of the polythiol.

[Experimental Example 1]

Polythiol  Of the curing agent of the copolymer structure Curing temperature  Measure

Polythiol formed by copolymerization of a polythiol formed by polymerization of a silane monomer containing a thiol functional group and a silane monomer containing a silane monomer containing a thiol functional group and a curing accelerating functional group (-OH) as in Production Examples 1 and 2 DSC analysis was carried out to determine the curing temperature of the curing agent of the cohesive structure. The curing agent of the polythiol copolymer structure according to Production Example 1 and the polythiol polymer according to Comparative Example 2 were each mixed with an epoxy resin as a curing agent and DSC analysis was carried out to measure the curing temperature of the epoxy resin. The DSC measurement results are shown in Fig.

6 (a) is a graph showing the results of DCS analysis of the polythiol polymer according to Comparative Example 1, and as shown, it was confirmed that the curing temperature of the polythiol polymer was 84.54 ° C. 6 (b) to 6 (c) are graphs showing the DSC analysis results of the curing agent of the polythiol copolymer structure according to Production Example 1 and Production Example 2, respectively, and the curing temperatures were found to be 77.89 ° C and 76.15 ° C, respectively . The curing agent of the polythiol copolymer structure prepared by copolymerizing a silane monomer containing a hydroxyl group (-OH) as a curing accelerating functional group with a silane monomer containing a thiol functional group has a curing temperature of 6 to 8.5 DEG C It can be confirmed that it is lowered.

Further, the polythiol copolymer according to Production Example 2 was copolymerized with the addition of a silane monomer containing a curing promoting functional group more than Production Example 1. As the content of the curing promoting functional group was larger, the curing promoting property was further increased It can be confirmed that the curing temperature is lowered.

As a result of the above experimental results, it is possible to improve the curing accelerating property of the curing agent through copolymerization of the silane monomer containing a thiol functional group and the silane monomer containing a curing accelerating functional group, and to improve the curing acceleration property according to the copolymerization ratio .

In the above Preparation Examples and Experimental Examples, a curing agent of a polythiol copolymer structure was prepared using a hydroxyl group (-OH) as one of the curing accelerating functional groups as an example, and it was confirmed that the curing temperature was improved. However, . The present invention relates to a process for preparing a curing agent of a polythiol copolymer structure by various combinations of a monomer containing a thiol group and a monomer containing a curing accelerating functional group and / or a functional group capable of controlling reactivity or physical properties, The present invention is characterized in that it is possible to control the curing accelerating functional group and / or the functional group capable of controlling the reactivity or physical properties as well as the properties of the epoxy resin To provide a curing agent having the characteristics.

In addition, the latent curing catalyst prepared using the mechanofusion of the present invention is excellent in dispersibility, interfacial adhesion, and storage stability, and thus has suitable characteristics as a one-pack type epoxy adhesive composition.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (17)

Epoxy resin;
A curing agent of a polythiol copolymer structure; And
A latent curing catalyst of a core shell structure,
The polythiol copolymer structure is preferably a polythiol-
A monomer having a thiol functional group in an inorganic silane main chain; And
At least one repeating unit selected from a first repeating unit including a curing accelerating functional group capable of controlling the curing behavior of the monomer and the adhesive and a second repeating unit including a functional group capable of controlling the reactivity or physical properties of the adhesive ; And,
The functional group capable of controlling the curing behavior of the monomer and the adhesive is any one or more curing accelerating functional groups selected from a primary amine group, a secondary amine group, a tertiary amine group, a carboxyl group, a hydroxyl group and derivatives thereof Including,
Wherein the functional group capable of controlling the reactivity or physical properties of the adhesive includes at least one selected from the group consisting of a hydroxyl group, an epoxy group, an aliphatic hydrocarbon group, a cyanating group, an imidazole group, and derivatives thereof.
The method according to claim 1,
Wherein the epoxy resin comprises a compatibilized epoxy resin comprising bisphenol A or bisphenol F.
The method according to claim 1,
Wherein the latent curing catalyst content of the core shell structure is 1 wt% to 5 wt% of the epoxy resin content.
The method according to claim 1,
Wherein the first repeating unit is formed by polymerization of a monomer functionalized with at least one monomer and a functional group capable of controlling the curing behavior of the adhesive.
delete The method according to claim 1,
Wherein the second repeating unit is formed by polymerization of a monomer functionalized with a functional group capable of controlling the reactivity or physical properties of at least one adhesive.
delete The method according to claim 1,
Wherein the polythiol comprises a compound represented by the following formula (1) or (2): < EMI ID =

(In the above formula (1) or (2)
L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,
And R is an alkyl group having between 1 and 10 carbons.
The method according to claim 1,
Wherein the first repeating unit comprises a compound represented by the following general formula (3) or (4): < EMI ID =

(In the above formula (3) or (4)
L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,
R is an alkyl group having between 1 and 10 carbons,
And X is a curing accelerating functional group).
The method according to claim 1,
Wherein the second repeating unit comprises a compound represented by the following general formula (5) or (6): < EMI ID =

(In the above Chemical Formula 5 or Chemical Formula 6,
L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,
R is an alkyl group having between 1 and 10 carbons,
Y is a functional group capable of controlling the reactivity or physical properties of the adhesive).
The method according to claim 1,
Wherein the copolymer comprises a copolymer represented by the following general formula (7) or (8): < EMI ID =

(In the above formula (7) or (8)
L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,
R is an alkyl group having between 1 and 10 carbons,
X is a cure accelerating functional group,
i and j are each independently an integer of 1 or more).
The method according to claim 1,
Wherein the copolymer comprises a copolymer represented by the following general formula (9) or (10): < EMI ID =

(In the above formula (9) or (10)
L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,
R is an alkyl group having between 1 and 10 carbons,
Y is a functional group capable of controlling the reactivity or physical properties of the adhesive,
l and m are each independently an integer of 1 or more).
The method according to claim 1,
Wherein the copolymer comprises a copolymer represented by the following general formula (11) or (12): < EMI ID =

(In the above formula (11) or (12)
L is a direct bond or a chain or branched alkylene group having 1 to 10 carbons, or a divalent radical of an aromatic hydrocarbon, and may include at least one element selected from oxygen and nitrogen,
R is an alkyl group having between 1 and 10 carbons,
X is a cure accelerating functional group,
Y is a functional group capable of controlling the reactivity or physical properties of the adhesive,
a, b and c each independently represents an integer of 1 or more).
The method according to claim 1,
The latent curing catalyst of the core-
A core comprising a curing agent material; And
And a shell comprising a protective film formed on a surface of the core and a filler particle physically chemically bonded to the protective film by mechanofusion.
15. The method of claim 14,
Wherein the curing agent material comprises at least one selected from the group consisting of an amine based adduct, a dicyandiamide-based material, a dihydride compound, and a dichlorophenyldimethylurea compound.
15. The method of claim 14,
Wherein the protective film is an isocyanate compound.
15. The method of claim 14,
The filler particles may be selected from the group consisting of polystyrene, polymethyl methacrylate, polyvinyl acetate, ethylene-vinyl acetate copolymer, acrylate, acryl-ester copolymer, styrene, styrene-acrylate copolymer, polyurethane, rubber latex, Silver, nickel, aluminum, lead, zinc, metal alloys, indium tin oxide, silver oxide, gold or silver coated nickel, silver coated copper Silver-coated aluminum, metal coated glass spheres, metal coated fillers, metal coated polymers, silver coated fibers, silver coated spheres, antimony doped tin oxides, conductive nanospheres, carbon black, carbon Fiber, graphite, and carbon nanotube. The one-component type When the adhesive composition.

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