KR102477301B1 - Autocatalytic polyurethane and epoxy adhesive composition including the same - Google Patents

Abstract

The present invention relates to a self-catalyzed polyurethane polymer and an epoxy adhesive composition containing the same, and more particularly, to an alicyclic terminal isocyanate group of a polyurethane prepared by polymerizing polyisocyanate, a polyol and a crosslinking agent, etc. By capping with a group tertiary amine capping agent, the self-catalyzed polyurethane polymer has excellent storage stability at room temperature and includes a catalytic functional group at the end that can act as a catalyst for epoxy curing reaction at high temperature, and the self-catalyzed polyurethane polymer The present invention relates to an epoxy adhesive composition that has a simplified manufacturing process, is economical, can be manufactured as a one-component adhesive, and has excellent storage stability.

Description

Autocatalytic polyurethane and epoxy adhesive composition including the same}

The present invention relates to a self-catalyzed polyurethane polymer and an epoxy adhesive composition containing the same, and more particularly, to a polyurethane prepared by polymerizing a polyisocyanate, a polyol, a crosslinking agent, etc., in which a terminal isocyanate group is blocked with a tertiary amine. By capping using an alicyclic tertiary amine capping agent, a self-catalyzed polyurethane polymer having excellent storage stability at room temperature and containing a catalytic functional group at the terminal that can act as a catalyst for epoxy curing reaction at high temperature, and the polyurethane polymer It relates to an epoxy adhesive composition having a simplified manufacturing process, economical, capable of being manufactured as a one-component adhesive, and having excellent storage stability.

Epoxy composition composed of epoxy resin and amine curing agent is a structural adhesive used in the manufacture of automobiles and aircraft. It is useful for metal bonding, composite material bonding, metal-composite material, and metal-plastic material bonding. It is widely used as an eco-friendly adhesive material that does not emit during the curing process.

The reaction temperature of the epoxy resin composition can be controlled by the amount of the tertiary amine catalyst used, and the epoxy resin composition as an adhesive for automobiles is usually cured at 170 to 180 °C. In the case of amine catalysts, imidazole or urea derivatives are widely used. An adhesive composition containing an epoxy resin is a binder resin composed of an epoxy resin, a curing agent and a reaction catalyst (accelerator), an inorganic filler, a polymer type toughening agent, a core/shell toughening agent, a thixotropic reagent, a coupling reagent, a glass bead, and a reactive agent. A number of additives such as a diluent are additionally included.

Epoxy compositions show high lap shear strength when cured, but also have brittleness that is easily broken by impact like glass. Therefore, when used as an adhesive material for automobiles, imparting toughness has been an important research topic. Accordingly, elastic polyurethane is used as an important material for improving the lap shear strength and T-peel strength of the epoxy composition and at the same time imparting toughness so that the cured epoxy material has a property that is not easily broken.

Since it was synthesized by Otto Bayer in the late 1930s, polyurethane has been used as an important additive for adhesives, coatings, and paints, and is a polymer compound widely used as a binder for inks and paints.

Polyurethane is synthesized by the reaction of various reactants, which are a polyol having two alcohol groups, a compound having two isocyanate groups, a chain extender having two alcohol groups or an amine group, or a crosslinking agent having three or more alcohol groups ( It consists of a cross linker), a tin-based or amine-based catalyst, and a capping agent that caps the isocyanate groups at both ends of polyurethane resulting from the reaction between polyol and isocyanate compound.

Both ends of the alcohol group of the extender or crosslinker react with the isocyanate functional group reacted with the polyol to form a peptide bond. As a result, soft segments composed of polyether and hard segments composed of peptide bonds connecting other soft segments are created. Polyurethane having such a hard part and a soft part is called a polyurethane elastomer.

The soft part made in this way has a non-polar property and has a glass transition temperature (Tg) lower than room temperature, and the hard part has a polar property and has a glass transition temperature (Tg) higher than room temperature, and the temperature at which the epoxy composition is cured. Phase separation occurs at (170 to 180 ° C.), which has an important effect on the improvement of physical properties such as toughness and impact resistance of the cured epoxy composition.

Due to these advantages, as polyurethane is added as a toughness additive to the epoxy adhesive composition, the number of compositions giving functionality in the binder composed of the basic main material, the epoxy resin, the curing agent, and the catalyst, gradually increases as needed, and accordingly, as an adhesive It is a disadvantage that the difficulty in manufacturing the adhesive is amplified by the increasing number of parts to be considered in the reactivity or manufacturing process of the adhesive. In Japanese Patent Laid-open Publication No. 1993-125144, an epoxy resin with improved impact resistance is prepared by dispersing a urethane prepolymer in an epoxy prepolymer, and in US Patent Publication No. 7,557,169, 2-allylphenol, 2-(n-penta Epoxy resin with improved impact resistance is manufactured by adding polyurethane capped with -8`-decenyl)phenol and curing it. In the above two inventions, in order to promote the epoxy curing reaction and control the reaction temperature, additionally adding an activated amine compound or urea as a reaction catalyst in a separate step, and further adding additives used together with the reaction catalyst Accordingly, there is a disadvantage in that the manufacturing cost of the epoxy resin adhesive rapidly increases and the manufacturing process of the epoxy adhesive becomes complicated. Epoxy adhesives of the prior art, including the above two inventions, further include catalysts such as expensive urea and activated amine compounds as additional components in addition to catalysts such as expensive urea and activated amine compounds to improve curing reactivity and adhesive efficiency. Not only does the manufacturing process of epoxy adhesive become complicated, but insoluble solid additives exist in the adhesive, making it impossible to manufacture a one-component adhesive, thereby limiting the application range of the adhesive, and the epoxy catalytic reaction is excessively fast. As the gelation of the adhesive occurs at high speed, it is difficult to manufacture a high-quality adhesive compared to the manufacturing cost, resulting in low manufacturing efficiency.

Japanese Unexamined Patent Publication No. 1993-125144 US Patent Registration No. 7,557,169

In order to solve the above problems, the present invention has excellent storage stability at room temperature and exhibits catalytic activity of the epoxy curing reaction in a specific temperature range, so that the self-catalyzed polyurethane polymer can simultaneously act as a toughness additive and catalyst in an epoxy adhesive composition. for the purpose of providing

Specifically, a terminal isocyanate group of polyurethane prepared by polymerizing a composition of polyisocyanate, polyol and crosslinking agent is blocked with a sulfonic acid compound such as arylsulfonic acid, alkylarylsulfonic acid and cycloalkylsulfonic acid. Capping using an alicyclic tertiary amine containing an alicyclic tertiary amine has excellent storage stability at room temperature and exhibits catalytic activity of the epoxy curing reaction in a specific temperature range, thereby acting as a toughness additive and catalyst in an epoxy adhesive composition. Catalyst at the terminal. It is an object to provide a self-catalyzing polyurethane polymer comprising functional groups.

In addition, by including the polyurethane polymer, the use of additional additives used in the prior art can be minimized, so the manufacturing process is simplified and cost-effective, it is possible to manufacture a one-component adhesive, and epoxy has excellent storage stability. It aims at providing an adhesive composition.

One aspect of the present invention for achieving the above object is prepared from a composition comprising a polyisocyanate, a polyol, a crosslinking agent and a capping agent, wherein the capping agent is C ₆ to C ₂₄ arylsulfonic acid, C ₇ to C ₂₄ alkyl It may be a self-catalyzed polyurethane polymer characterized by being an alicyclic tertiary amine blocked with any one or two or more sulfonic acid-based compounds selected from arylsulfonic acid and C ₆ to C ₂₄ alicyclic alkylsulfonic acid.

As one aspect of the present invention, the sulfonic acid-based compound may be any one or two or more compounds selected from camphorsulfonic acid, benzenedisulfonic acid, naphthalenesulfonic acid, and dodecylbenzenesulfonic acid.

In one aspect of the present invention, the alicyclic tertiary amine is C ₆ to C ₂₀ hydroxyalkyl piperidine, C ₅ to C ₂₀ hydroxyalkyl pyrrolidine, C ₅ to C ₂₀ hydroxyalkyl molar It may be any one or two or more compounds selected from the group consisting of porin and C ₆ to C ₂₀ hydroxy piperidine alcohol.

As one aspect of the present invention, the capping agent may be prepared by including the sulfonic acid-based compound and an alicyclic tertiary amine in an amount of 1:0.5 to 1.5.

In one aspect of the present invention, the hydroxyl group of the polyol included in the composition of the self-catalyzed polyurethane polymer is 0.4 to 1 molar equivalent with respect to the total number of moles of isocyanate groups of the polyisocyanate included in the composition, and the hydroxyl group of the crosslinking agent is 0.005 to 0.08 molar equivalents based on the total number of moles of the isocyanate groups, and the content of the capping agent may be 0.5 to 2 molar equivalents based on the total number of moles of the isocyanate groups.

Another aspect of the present invention relates to an epoxy adhesive composition comprising the self-catalyzed polyurethane polymer.

As one aspect of the present invention, the polyurethane polymer may be a polymer having a weight average molecular weight of 9,000 to 50,000 and a polydispersity index of 1.5 to 10.

As one aspect of the present invention, the epoxy adhesive composition may include 10 to 30 parts by weight of the polyurethane polymer based on 100 parts by weight of the epoxy resin, and may be cured at 160 to 180 ° C.

As one aspect of the present invention, the epoxy adhesive composition may be characterized by satisfying the following relational expression 1.

[Relationship 1]

< 180 [단위 : ℃]160 <

< 180 [Unit : ℃]

(In Equation 1, T _peak is the maximum exothermic temperature (° C.) during the exothermic curing reaction of the epoxy adhesive composition, and T _onset is the exothermic start temperature (° C.) during the exothermic curing reaction of the epoxy adhesive composition. At this time, the exothermic curing reaction The temperature is based on the measurement by differential scanning calorimetry (DSC), and the heating temperature is 10 ° C / min.)

The self-catalyzed polyurethane polymer according to the present invention is an alicyclic tertiary amine containing a tertiary amine group in which the terminal isocyanate group is blocked with a sulfonic acid-based compound such as arylsulfonic acid, alkylarylsulfonic acid, and cycloalkylsulfonic acid. As it is capped, the curing reaction of the epoxy resin can be accelerated at a relatively low temperature of 160 to 180 ° C., and the mechanical properties of the epoxy resin can be improved at the same time, thereby acting as a toughness additive and an epoxy curing reaction catalyst in the epoxy adhesive composition. can be done

In addition, the epoxy adhesive composition according to the present invention includes the polyurethane polymer in liquid form exhibiting a catalytic activity of the epoxy curing reaction at a low temperature range of 160 to 180 ° C. as a toughness additive, and thus a separately added solid additive such as a catalyst It can be manufactured as a one-component epoxy adhesive by minimizing the use of adhesive, effectively lowering the curing reaction temperature of epoxy, and maximizing storage stability, thereby simplifying the manufacturing process of epoxy adhesive and improving economic efficiency in terms of manufacturing cost. maximal effect can be obtained.

1 is a graph of maximum exotherm of the epoxy adhesive composition according to Example 3,
Figure 2 is a graph of the maximum exotherm of the epoxy adhesive composition according to Example 4.

Hereinafter, the self-catalyzing polyurethane polymer of the present invention and the epoxy adhesive composition including the same will be described in detail. The embodiments introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. In addition, if there are no other definitions in the technical terms and scientific terms used, they have meanings commonly understood by those of ordinary skill in the art to which this invention belongs, and will unnecessarily obscure the gist of the present invention in the following description. Descriptions of possible known functions and configurations are omitted.

In the terminology of the present invention, "accelerator" is used as a word meaning '(reaction) catalyst of the curing reaction of epoxy'.

The present invention relates to a self-catalyzing polyurethane polymer comprising a functional group acting as a curing catalyst at the terminal during a curing reaction of an epoxy resin, and is specifically prepared from a composition containing polyisocyanate, a polyol, a crosslinking agent and a capping agent. The capping agent is tertiary by any one or two or more sulfonic acid-based compounds selected from C ₆ to C ₂₄ arylsulfonic acid, C ₇ to C ₂₄ alkylarylsulfonic acid, and C ₆ to C ₂₄ alicyclic alkylsulfonic acid. It relates to a self-catalyzed polyurethane that is an alicyclic tertiary amine with an amine group blocked.

In the present invention, the polyisocyanate is not particularly limited, but may be an aliphatic or alicyclic polyisocyanate compound having 2 or more isocyanate groups (-NCO; functional group), preferably an aliphatic or alicyclic polyisocyanate compound having 2 to 5 functional groups. An isocyanate compound, more preferably an aliphatic or alicyclic polyisocyanate compound having two functional groups. For example, 1,6-hexamethylene diisocyanate, 3,5,5-trimethyl-1-isocyano-3-isocyanatomethylcyclohexane, trimethylhexamethylene diisocyanate, methylenediphenyl diisocyanate, toluene di Isocyanate, 1,4-butylene diisocyanate, isophorone diisocyanate, bis(4,4'-isocyanatocyclohexyl)methane, 1,4-cyclohexylene diisocyanate, 4-isocyanatomethyl- Any one or two or more compounds selected from 1,8-octane diisocyanate and alkyl-2,6-diisocyanatohexanoate having an alkyl group having 1 to 8 carbon atoms may be used.

In addition, the polyisocyanate of the present invention is a modified diisocyanate having a structure of uretdione, isocyanurate, urethane, allophanate, biuret, iminooxadiazinedione or oxadiazinetrione having two or more functional groups. It may be a mixture containing

In the present invention, the polyol is not particularly limited, but may be a polymer polyol having a weight average molecular weight of 1,000 to 6,000 g/mol and a number of hydroxyl groups (—OH; functional groups) of 2 to 6, and specifically, polyetherdiol, Bisphenol A, bisphenol S, polypropylene glycol, polybutylene glycol, trimethylolpropane, glycerol, erythritol, pentaerythritol, trimethylolbenzene and trishydroxyethyl isocyanurate, polyester polyols, polyether polyols, poly acrylate polyols, polyurethane polyols, polycarbonate polyols, polyester polyacrylate polyols, polyurethane polyacrylate polyols, polyurethane polyester polyols, polyurethane polyether polyols, polyurethane polycarbonate polyols and polyester polycarbonate polyols, etc. Any one or two or more selected compounds may be used, and among them, polytetrahydrofuran diol may be most preferably used. The number of functional groups of the polyol used in the present invention is preferably 2, but is not particularly limited thereto, and the hydroxyl group of the polyol included in the composition of the self-catalyzed polyurethane polymer of the present invention is 0.4 based on the total number of moles of the isocyanate group. to 1 molar equivalent, preferably 0.5 to 0.7 molar equivalent, but is not particularly limited.

In the present invention, the crosslinking agent is a material added for the crosslinking reaction of the linear or branched polyurethane prepolymer prepared by polymerization of the polyisocyanate compound and the polyol compound, and is not particularly limited, but is not limited to, hydroxyl group (—OH; functional group ) may be an aliphatic, alicyclic or aromatic polyol compound having 3 to 6, preferably an aliphatic, alicyclic or aromatic polyol compound having 3 functional groups. For example, any one or two or more compounds selected from trimethylolpropane and 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenol (TPT), etc. It may be used, preferably 4,4 ', 4 "-(1,3,5-triazine-2,4,6-triyl) triphenol (TPT) may be used, but is not limited thereto. The hydroxyl group of the crosslinking agent included in the composition of the self-catalyzed polyurethane polymer of the present invention is preferably included in an amount of 0.005 to 0.08 molar equivalent, preferably 0.01 to 0.07 molar equivalent, based on the total number of moles of the isocyanate group, but is not particularly limited thereto. .

In the self-catalyzed polyurethane polymer of the present invention, the terminal isocyanate group of the polyurethane prepared through polymerization of the polyisocyanate, the polyol, and the crosslinking agent is bonded to a capping agent having a characteristic of exhibiting a curing reaction catalytic activity of an epoxy resin (hereinafter Being capped, it can be included in the epoxy adhesive composition and act as a toughness additive that improves the mechanical properties of the epoxy resin, as well as an accelerator that promotes the curing reaction by lowering the temperature of the curing reaction of the epoxy resin. has the characteristics of

In the present invention, the capping agent is a compound in which a sulfonic acid-based compound and an alicyclic tertiary amine are chemically bonded, and among the functional groups included in the alicyclic tertiary amine, the sulfone is added to the tertiary amine group capable of accelerating the epoxy curing reaction. It is a compound in which the catalytic action of the tertiary amine group is deactivated (hereinafter referred to as block) by binding the sulfonic acid group (-SO ₃ H) of the acid compound.

At this time, the sulfonic acid-based compound is any one or two or more sulfonic acid-based compounds selected from C ₆ to C ₂₄ arylsulfonic acid, C ₇ to C ₂₄ alkylarylsulfonic acid, and C ₆ to C ₂₄ alicyclic alkylsulfonic acid. It may be, preferably any one or two or more compounds selected from camphorsulfonic acid, benzenedisulfonic acid, naphthalenesulfonic acid, and dodecylbenzenesulfonic acid. It can be, but is not particularly limited thereto.

In addition, the alicyclic tertiary amine of the present invention may be a tertiary amine and an alicyclic tertiary amine compound containing one or more hydroxyl groups, preferably C ₆ to C ₂₀ hydroxyalkyl piperidine (hydroxyalkyl piperidine), C ₅ to C ₂₀ hydroxyalkyl pyrrolidine, C ₅ to C ₂₀ hydroxyalkyl morpholine and C ₆ to C ₂₀ hydroxy piperidine alcohol (hydroxy piperidine alcohol) and the like, and more preferably 1-(2-hydroxyethyl)piperidine, 1-(2-hydroxyethyl)pyrrolidine, It may be any one or two or more compounds selected from 4-(2-hydroxyethyl)morpholine, 4-hydroxy-1-piperidineethanol, etc., but is not particularly limited thereto.

The capping agent of the present invention may be prepared by including the sulfonic acid-based compound and the alicyclic tertiary amine in an amount of 1:0.5 to 1.5 equivalents, preferably 1:0.8 to 1 equivalent. Abuse of the sulfonic acid-based compound can be avoided by using the sulfonic acid-based compound and alicyclic tertiary amine used in the preparation of the capping agent in the equivalent amount, and the tertiary amine group present in the alicyclic tertiary amine is added to the sulfonic acid-based compound. It is possible to manufacture a capping agent blocked by the capping agent, and only when the self-catalyzed polyurethane polymer of the present invention, which is end-capped with the capping agent, is heated to an epoxy curing reaction temperature, the sulfonic acid-based compound is dissociated to obtain a tertiary amine group. Epoxy curing catalyst reactivity (catalytic activity) can be selectively exhibited, and accordingly, when the self-catalyzed polyurethane polymer is included as a toughness additive in an epoxy adhesive composition, it is possible to prepare an adhesive composition with excellent storage stability compared to the prior art, which is preferable. .

In addition, the content of the capping agent included in the composition of the self-catalyzed polyurethane polymer of the present invention is preferably 0.5 to 2 molar equivalents, preferably 0.8 to 1.5 molar equivalents, based on the total number of moles of isocyanate groups included in the composition. . When the self-catalyzed polyurethane polymer of the present invention is prepared, an appropriate amount of tertiary amine group can be formed at the end of the polyurethane by including the capping agent in the above content range, and the self-catalyzed polyurethane polymer of the present invention thus prepared is epoxy When included as a toughness additive in the adhesive composition, it is possible to derive similar or more improved mechanical property improvement effects of epoxy compared to the use of the prior art toughness additive, and at the same time, it is possible to accelerate the epoxy curing reaction without using an additional accelerator, and omit the accelerator. Through this, it is also possible to manufacture a one-component adhesive, which is preferable.

The self-catalyzed polyurethane polymer according to the present invention may further include any one or two or more additives selected from a catalyst and a chain extender as needed in addition to the polyisocyanate, polyol, crosslinking agent and capping agent during the synthesis process.

The catalyst is a polymerization catalyst for accelerating the polymerization reaction of the self-catalyzed polyurethane polymer of the present invention, and is not particularly limited as long as it is a catalyst commonly used in the polymerization reaction of polyurethane in the art. For example, amine-based catalysts, organic Any one or two or more selected from titanium compound-based and organotin compound-based catalysts may be used, and dibutyl tin dilaurate or di-n-butylbis( Dodecylthio)tin (di-n-butylbis(dodecylthio)tin) may be used.

The chain extender has at least one functional component of -NH ₂ and -NH components, but is not particularly limited thereto, but diamines or polyamines such as ethylenediamine, 1,2-diaminopropane, 1,3-dia Minopropane, 1,4-diaminobutane, 1,6-diaminohexane, isophoronediamine, an isomeric mixture of 2,2,4- and 2,4,4-trimethylhexamethylenediamine, 2-methylpentamethylenediamine , diethylenetriamine, diaminodicyclohexylmethane or dimethylethylenediamine may be used.

The self-catalyzed polyurethane polymer according to the present invention has the advantage of not requiring a separate solvent in the synthesis process because the polyol melts at a high temperature of 80 to 95 °C.

In addition, the present invention is to provide an epoxy adhesive composition comprising the self-catalyzed polyurethane polymer.

In the present invention, the self-catalyst polyurethane polymer may be a polyurethane polymer having a weight average molecular weight of 9,000 to 50,000 and a polydispersity index of 1.5 to 10. The self-catalyzed polyurethane polymer is included in the epoxy adhesive composition of the present invention, and can exhibit the effect of adding a toughness additive that improves mechanical properties such as lap shear strength and peel strength of the epoxy resin, and has a temperature of 160 to 180 ° C. As it acts as a catalyst for the epoxy curing reaction in the temperature range and accelerates the curing reaction of the epoxy adhesive, it can show the same effect as the case of adding an accelerator without using an additional curing accelerator, and the use of an additional accelerator as described above As this can be omitted, it is possible to reduce the composition included to impart the functionality of the adhesive, thereby simplifying the manufacturing process of the adhesive and producing a one-component adhesive.

Specifically, the epoxy adhesive composition to which the self-catalyst polyurethane polymer is added and the accelerator is not added may satisfy the following relational expression 1.

[Relationship 1]

< 180 [단위 : ℃]160 <

< 180 [Unit : ℃]

(In Equation 1, T _peak is the maximum exothermic temperature (° C.) during the exothermic curing reaction of the epoxy adhesive composition, and T _onset is the exothermic start temperature (° C.) during the exothermic curing reaction of the epoxy adhesive composition. At this time, the exothermic curing reaction The temperature is based on the measurement by differential scanning calorimetry (DSC), and the heating temperature is 10 °C/min.)

인 지점의 온도를 경화온도(T_cure)로 볼 수 있다. 즉, 본 발명에 따른 에폭시 접착제 조성물은 160℃ 초과, 180 ℃ 미만인 온도 범위에서 경화 반응이 시작됨에 따라, 앞서 설명한 바와 같이, 추가적인 경화 촉진제의 사용 없이도 촉진제를 첨가한 경우와 동등한 효과를 나타낼 수 있으며, 160℃ 초과에서 경화 반응이 시작됨에 따라 상온(20 내지 25℃)에서는 매우 우수한 저장안정성을 가질 수 있다. 이에 따라, 160℃ 초과의 온도를 가하는 가열 과정에서만 촉매반응이 선택적으로 발생하여, 일액형 접착제로의 제조가 가능하며, 우수한 접착 효율을 나타내는 에폭시 접착제의 제조가 가능하다.In detail, relational expression 1 is related to the curing temperature of the epoxy adhesive composition,

The temperature at the in-point can be viewed as the curing temperature (T _cure ). That is, as the curing reaction starts in the temperature range of more than 160 ° C and less than 180 ° C, the epoxy adhesive composition according to the present invention, as described above, can exhibit the same effect as the case of adding an accelerator without using an additional curing accelerator, , As the curing reaction starts at more than 160 ° C, it can have very good storage stability at room temperature (20 to 25 ° C). Accordingly, a catalytic reaction selectively occurs only during a heating process in which a temperature of more than 160° C. is applied, making it possible to manufacture a one-component adhesive and to manufacture an epoxy adhesive exhibiting excellent adhesion efficiency.

The epoxy adhesive composition of the present invention may include an epoxy resin and a curing agent as essential components in addition to the self-catalyzing polyurethane polymer.

In the present invention, the epoxy resin is at least one epoxy resin selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, and alicyclic type epoxy resin. Any epoxy resin commonly used in the art may be used without being particularly limited thereto.

In the present invention, the curing agent is an epoxy resin curing agent added to promote the curing reaction of the epoxy adhesive composition, and the curing agent is any one or more compounds selected from the group consisting of aliphatic polyamines, aromatic amines, and modified aliphatic polyamines. It can be used, preferably selected from diethylenetriamine, triethylenetetramine, diethylaminopropylamine, methanediamine, dicyandiamine, metaphenylenediamine, 4,4'-dimethylaniline and diaminodiphenylsulfone. Any one or more compounds may be used, but are not particularly limited thereto, and any epoxy resin curing agent commonly used in the art may be used.

The epoxy adhesive composition according to the present invention may further include any one or two additives selected from a coupling agent and a filler in addition to the epoxy resin and the curing agent, if necessary.

The epoxy adhesive composition of the present invention may include 10 to 30 parts by weight of the self-catalyzed polyurethane polymer based on 100 parts by weight of the epoxy resin, and may be cured at 160 to 180 °C. The content of the self-catalyzed polyurethane polymer used in the preparation of the epoxy adhesive composition is not particularly limited thereto, but when the above range is satisfied, the curing reaction of the epoxy adhesive composition proceeds rapidly in the temperature range of 160 to 180 ° C. Efficiency is improved, and excellent overlap shear strength and peel strength of the epoxy resin subjected to the curing reaction can be obtained, which is preferable.

The polymerization method of elastic polyurethane according to the present invention and the elastic polyurethane polymer prepared therefrom will be described in more detail through the following examples. However, the following examples are only one reference for explaining the present invention in detail, but the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, 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. The terminology used in the description herein is merely to effectively describe specific embodiments and is not intended to limit the present invention.

In addition, the drawings introduced below are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Therefore, the present invention may be embodied in other forms without being limited to the drawings presented below, and the drawings presented below may be exaggerated to clarify the spirit of the present invention. Also, like reference numerals denote like elements throughout the specification.

Also, the singular forms used in the specification and appended claims may be intended to include the plural forms as well, unless the context dictates otherwise.

First, the method of the experiment conducted in the present invention is presented.

The physical properties of the polyurethane polymer synthesized through the following Examples and Comparative Examples and the adhesive composition containing the same were measured as follows and are shown in Table 1, Table 2, FIG. 1 or 2.

Experiment 1) Lap shear strength measurement

Lap shear strength was measured according to the ASTM D 1002 standard.

A SPRC 440R (Steel Plate Rephosphorized Cold Rolled) cold-rolled steel sheet having a maximum tensile strength of 440 MPa, a length and width of 100 × 25 mm, and a thickness of 1.6 mm was used as an adherend. An adhesive was applied to an area of 12.7 × 25 mm at the end of the adherend, and at this time, the thickness of the adhesive surface was adjusted using glass beads to make the thickness of 0.2 to 0.25 mm. After curing the test piece prepared by the above method at 170 ° C for 25 minutes, the overlap shear strength was measured using a universal testing machine at room temperature (23 ° C). At this time, the testing speed of the universal testing machine was applied at 1.3 mm / min.

Experiment 2) T-peel strength measurement

Measurement of T-peel strength was performed according to the ASTM D 1876 standard.

SPCC (steel plate cold commercia) cold-rolled steel sheet having a length and width of 150 × 25 mm and a thickness of 0.8 mm was used as an adherend. An adhesive was applied to the adherend, and the length and width of the adhesive portion were processed into a 'L' shape so that the length and width of the adherend were respectively 80 × 25 mm. After curing the test piece prepared by the above method at 170 ° C for 25 minutes, the overlap shear strength was measured using a universal testing machine at room temperature (23 ° C). At this time, the testing speed of the universal testing machine was applied at 254 mm / min. The experimental results were presented by collecting the results from the point at which the peeling of the adhesive surface of the test piece started to 50 mm.

Experiment 3) Investigation of curing temperature (T _cure )

It was observed using a differential scanning calorimetry (TA DSC Q-200). As for the reactivity, the maximum exothermic temperature (T _peak ) was measured during the curing process of the composition while the temperature was raised from 25 ° C to 300 ° C in an N ₂ atmosphere at 10 ° C / min, and curing was performed by calculating the T _oneset and 1/2 point of T _peak The temperature (T _cure ) was calculated. T _oneset means the temperature at the point where the baseline and the tangent of the exothermic curing graph are interpolated by extrapolation.

[Example 1] Synthesis of polyurethane polymer (A1) using an alicyclic tertiary amine blocked with camphorsulfonic acid as a capping agent

(a)

(a)

(b)

(b)

(c)

(c)

80 g (0.04 mol) of polytetrahydrofuran (PolyTHF 2000, Sigma Aldrich, USA) having a weight average molecular weight of 2,000 g/mol was put into a three-necked flask, and then heated at 86° C. to dissolve completely. Thereafter, 0.5 g (0.001 mol) of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenol as a crosslinking agent was mixed with 12 ml of hexamethylene diisocyanate (HMDI, 0.07 mol), mixed in polytetrahydrofuran, and a tin-based catalyst (di-n-butylbis(dodecylthio)tin, 0.8 μl) was added and reacted for 40 minutes. After the reaction, isocyanate end groups 12 ml (0.1 mol) of 1-(2-hydroxyethyl piperidine, Sigma Aldrich, USA) and camphorsulfonic acid (Sigma Aldrich, USA) were used as a capping agent to cap the After adding 25 g (0.1 mol) of a mixture of ), the temperature was raised to 110 ° C and reacted for 3 hours, and then the temperature was lowered to room temperature (20 ° C) to terminate the reaction, and the polyurethane polymer in the form of a highly viscous liquid (A1) was obtained The obtained polyurethane polymer (A1) had a number average molecular weight of 9,920 g/mol, a weight average molecular weight of 17,330 g/mol, and a polydispersity index of 1.7.

[Example 2] Synthesis of polyurethane polymer (A2) using alicyclic tertiary amine blocked with camphorsulfonic acid as a capping agent

(a)

(a)

(b)

(b)

(c)

(c)

In place of 0.5 g (0.001 mol) of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenol used as a crosslinking agent in Example 1, 1,1 Except for using 0.5 g (0.003 mol) of ,1-trimethylolpropane as a crosslinking agent, a liquid polyurethane polymer (A2) was prepared in the same manner as the rest. Number average molecular weight of the polyurethane polymer (A2) obtained above is 5,580 g/mol, the weight average molecular weight is 18,290 g/mol, and the polydispersity index is 3.3.

[Examples 3 to 4] Preparation of epoxy adhesive composition containing polyurethane polymer

An epoxy adhesive composition was prepared according to the following composition, and the maximum exothermic temperature results were shown in FIGS. 1 and 2 using the prepared epoxy adhesive compositions (Examples 3 and 4).

The epoxy resin used at this time is bisphenol A diglycidyl ether (Epikote 828, Momentive, USA), the curing agent is dicyandiamide (DICY; Dicyanex 1400F, Airproducts, Korea), and the accelerator is a urea catalyst (Amicure UR 7 /10, Airproducts, Korea). In addition, the coupling agent used below is a silane coupling agent containing an epoxy functional group (Silquest A-187, Momentive, USA), and the filler is calcium carbonate (omya, USA).

[Examples 5 to 6] Preparation of one-component epoxy adhesive composition containing polyurethane polymer

A one-component epoxy adhesive composition was prepared according to the following composition.

At this time, the curing agent used was methylhexahydrophthalic anhydride (MHHPA; Sigma Aldrich, USA) instead of the dicyandiamide (DICY), and the remaining epoxy resin, accelerator, coupling agent and filler except for this were used. It is the same as that used in Examples 3 to 4 above.

[Comparative Example 1] Synthesis of polyurethane polymer (A3) using 2-allylphenol as a capping agent

Except for using 20 g of 2-allylphenol as a capping agent instead of a mixture of 1-(2-hydroxyethyl)piperidine and camphorsulfonic acid used as a capping agent in Example 2 and a liquid polyurethane polymer (A3) was prepared in the same manner. The polyurethane polymer (A3) obtained above had a number average molecular weight of 12,210 g/mol, a weight average molecular weight of 27,820 g/mol, and a polydispersity index of 2.3.

[Comparative Example 2] Synthesis of polyurethane polymer (A4) using unblocked alicyclic tertiary amine as capping agent

In place of the mixture of 1-(2-hydroxyethyl)piperidine and camphorsulfonic acid used as the capping agent in Example 2, 1-(2-hydroxyethyl)piperidine 12 A liquid polyurethane polymer (A4) was prepared in the same manner except for using ㎖ as a capping agent. The obtained polyurethane polymer (A4) had a number average molecular weight of 6,790 g/mol, a weight average molecular weight of 13,780 g/mol, and a polydispersity index of 2.0.

[Comparative Examples 3 to 5] Preparation of epoxy adhesive composition containing polyurethane polymer

An epoxy adhesive composition was prepared according to the following composition.

The epoxy resin, curing agent, accelerator, coupling agent, and filler used at this time are the same as those used in Examples 3 to 4.

[Comparative Examples 6 to 7] Preparation of one-component epoxy adhesive composition containing polyurethane polymer

A one-component epoxy adhesive composition was prepared according to the following composition.

The epoxy resin, accelerator, coupling agent, and filler used at this time are the same as those used in Examples 3 and 4, and the curing agent is the same as that used in Examples 5 and 6.

The results of evaluating the epoxy adhesive compositions of Examples 3 to 4 and Comparative Examples 3 to 5 through the methods of Experiment 1 and Experiment 2 are shown in Table 1 below. In addition, the shape of the one-component epoxy adhesive composition prepared in Examples 5 to 6 and Comparative Examples 6 to 7 and the results of curing the adhesive composition at a temperature of 170 ° C are shown in Table 2 below.

Example 3 Example 4 Comparative Example 3 Comparative Example 4 Comparative Example 5 Lap shear strength
[MPa] 28.1 28.2 25.6 - - T-peel strength
[N/25mm] 189.2 180.1 177.2 - - note - - - hardening ×
(curing temperature: over 195℃) Occurrence of gelation reaction

Example 5 Example 6 Comparative Example 6 Comparative Example 7 Whether a one-component epoxy adhesive composition can be manufactured possible possible possible impossible
(gelation) Curing result at 170℃ hardening Ο hardening Ο hardening ×
(curing temperature:
above 206 ℃) -

Through the results of Examples and Comparative Examples in Tables 1 and 2, when the self-catalyzed polyurethane polymer according to the present invention is included in the epoxy adhesive composition, the curing of the epoxy resin can be achieved without separately including an accelerator (curing reaction catalyst). It can be seen that the curing reaction of the epoxy adhesive composition effectively occurs at a relatively low temperature of 170 ° C. during the heating process for

In addition, through the results of Example 3 and Comparative Example 5, in the case of the adhesive composition of Comparative Example 5 using a capping agent in which the tertiary amine of the alicyclic tertiary amine is not blocked, the tertiary amine is exposed to the epoxy resin as it is While the catalytic reaction is activated and a gelation reaction occurs, the adhesive composition of Example 3 uses a capping agent in which the tertiary amine of an alicyclic tertiary amine is blocked with sulfonic acid, so that it is present at the end of polyurethane It can be confirmed that the catalytic reaction of the tertiary amine to be selectively appears only at high temperature. Accordingly, when the self-catalyzed polyurethane of the present invention is included in the epoxy adhesive composition, the epoxy exhibits excellent storage stability because no catalytic reaction occurs at room temperature and exhibits excellent adhesive efficiency because the catalytic reaction selectively occurs only in the heating process for curing. It can be seen that the production of adhesives is possible.

In addition, through the results of Examples 3 to 4 and Comparative Example 3 in Table 1, compared to the epoxy resin of the composition of Comparative Example 3 further comprising a separate accelerator, the self-catalyzed polyurethane of the present invention without an accelerator It can be seen that the epoxy resins of the compositions of Example 3 and Example 4, including the above, exhibit similar or improved mechanical properties after curing, so that the production of epoxy adhesives having excellent physical properties by including the self-catalyst polyurethane of the present invention know that it is possible.

Claims (9)

It is prepared from a composition comprising a polyisocyanate, a polyol, a crosslinking agent and a capping agent,
The capping agent is blocked with any one or two or more sulfonic acid-based compounds selected from C ₆ to C ₂₄ arylsulfonic acid, C ₇ to C ₂₄ alkylarylsulfonic acid and C ₆ to C ₂₄ alicyclic alkylsulfonic acid A self-catalyzed polyurethane polymer that is a cycloaliphatic tertiary amine.
According to claim 1,
The sulfonic acid-based compound is a self-catalyzed polyurethane polymer, characterized in that any one or two or more selected from camphorsulfonic acid, benzenedisulfonic acid, naphthalenesulfonic acid and dodecylbenzenesulfonic acid.
According to claim 1,
The alicyclic tertiary amine is C ₆ to C ₂₀ hydroxyalkyl piperidine, C ₅ to C ₂₀ hydroxyalkyl pyrrolidine, C ₅ to C ₂₀ hydroxyalkyl morpholine and C ₆ to C ₂₀ A self-catalyzed polyurethane polymer, characterized in that any one or two or more compounds selected from the group consisting of hydroxy piperidine alcohol.
According to claim 1,
The capping agent is a self-catalyzed polyurethane polymer, characterized in that prepared by including the sulfonic acid compound and alicyclic tertiary amine in an amount of 1:0.5 to 1.5.
According to claim 1,
The hydroxyl group of the polyol included in the composition is 0.4 to 1 molar equivalent based on the total number of moles of isocyanate groups of the polyisocyanate, the hydroxyl group of the crosslinking agent is 0.005 to 0.08 molar equivalent based on the total number of moles of the isocyanate group, and the capping agent The self-catalyzed polyurethane polymer, characterized in that the content is 0.5 to 2 molar equivalents based on the total number of moles of the isocyanate group.
An epoxy adhesive composition comprising any one of autocatalytic polyurethane polymers selected from claims 1 to 5.
According to claim 6,
The polyurethane polymer is an epoxy adhesive composition, characterized in that the weight average molecular weight of 9,000 to 50,000, polydispersity index of 1.5 to 10.
According to claim 6,
The epoxy adhesive composition comprises 10 to 30 parts by weight of the polyurethane polymer based on 100 parts by weight of the epoxy resin, and is cured at 160 to 180 ° C.
According to claim 6,
The epoxy adhesive composition is an epoxy adhesive composition, characterized in that satisfies the following relational expression 1.
[Relationship 1]
160 <

< 180 [Unit : ℃]
(In the above relational expression 1, T _peak is the maximum exothermic temperature (℃) during the exothermic curing reaction of the epoxy adhesive composition, and T _onset is the exothermic start temperature (℃) during the exothermic curing reaction of the epoxy adhesive composition. At this time, the exothermic curing reaction The temperature is based on the measurement by differential scanning calorimetry (DSC), and the heating temperature is 10 ° C / min.)

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