KR101726955B1 - Self-healing and degradable epoxy resin composition - Google Patents

Abstract

Provided is an epoxy resin composition. The epoxy resin composition contains an epoxy resin, a curing agent, and an organic gel additive including hemiaminal groups which are bonded in a net-like form. The equivalent number of reactive curing groups in the curing agent is set to be 0.8 to 1.2 times greater than that of the epoxide groups in the epoxy resin. The content of the organic gel additive ranges from 0.1 to 60 parts by weight, if the total parts by weight of the epoxy resin and the curing agent together is set to be 100.

Description

[0001] Self-healing and degradable epoxy resin composition [0002]

The present invention relates to an epoxy resin composition, and more specifically to an epoxy adhesive composition.

Epoxy adhesives are excellent in mechanical properties and chemical resistance with respect to adhesive strength and surface stability, have little shrinkage deformation during curing and can control the curing rate. They are used as adhesives, electrical parts, electronic components, Inks, and product finishes.

However, despite the excellent durability and stability of the epoxy adhesive, the epoxy adhesive easily cracks due to the surrounding environment and external force due to brittleness, and when the epoxy adhesive is formed inside the epoxy film, the adhesive agent is peeled off through the crack, It is difficult to keep the fixing by the above.

In addition, the epoxy adhesive is a thermosetting adhesive composed of a main material having an epoxy functional group and a curing agent, and once the adhesive reaction has occurred, it is difficult to remove and it is impossible to decompose spontaneously.

Accordingly, an object of the present invention is to provide an epoxy adhesive composition capable of self-healing and decomposing cracks.

The technical objects of the present invention are not limited to the technical matters mentioned above, and other technical subjects not mentioned can be clearly understood by those skilled in the art from the following description.

According to one aspect of the present invention, there is provided an epoxy resin composition. The epoxy resin composition contains an organic gel additive comprising an epoxy resin, a curing agent, and network-bonded hemicyclic groups represented by the following formula (1). The curing agent may be contained such that the equivalent number of reactive reactive curing groups thereof is 0.8 to 1.2 times the equivalent number of epoxide groups in the epoxy resin. The organic gel additive may be contained in an amount of 0.1 to 60 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent.

[Chemical Formula 1]

In the general formula (1), R is any one of the compounds represented by the following general formula (2)

(2)

In Formula 2, R _1, R _2, and R ₃ is independently selected C2-C4 linear alkyl, branched alkyl C3-C4, or silyl group, n is 2 to 6, n + m is 2 to 12.

The epoxy resin composition according to an embodiment of the present invention contains an organic gel additive having network-bonded hemiaminal groups as shown in Formula 1, thereby exhibiting a self-healing property capable of re-adhesion after cutting Acid treatment It may also be possible to decompose through acid treatment, specifically with a pH of less than 3.

1 is a photograph showing an organic gel according to Production Examples 1 and 2 of Organic Gel Additives.
2 is a graph showing the viscosity of the epoxy adhesive compositions according to Comparative Example 2 and Production Examples 9 to 12.
FIGS. 3A and 3B are photographs showing a self-healing confirmation experiment process.
4 is a graph showing the tensile strengths of the adhesive films formed using the adhesive compositions according to Comparative Example 1 and Production Examples 1 to 8. Fig.
Fig. 5 is a graph showing the tensile strengths of the adhesive films formed using the adhesive compositions according to Comparative Example 2 and Production Examples 9 to 12. Fig.
FIG. 6 is a graph showing tensile strengths before and after re-bonding of the adhesive films formed using the adhesive compositions according to Production Examples 1 to 5. FIG.
FIG. 7 is a graph showing tensile strengths before and after re-bonding of the adhesive films formed using the adhesive compositions according to Production Examples 10 and 11. FIG.
8 is a photograph taken during the progress of the epoxy adhesive film decomposition experiment example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms.

When "Cx to Cy" is described in the present specification, the case where the number of carbon atoms corresponding to all the integers between the number of carbon atoms x and the number of carbon atoms y is also to be interpreted as described. In the present specification, n and m, which represent the number of repetition times of the repeating unit of the polymer compound, should be interpreted as having any value within the range unless otherwise defined.

Epoxy resin composition

The epoxy resin composition according to the present embodiment may contain an organic gel additive having an epoxy resin, a curing agent, and network-bonded hemiaminal groups represented by the following formula (1). The curing agent may be contained such that the equivalent number of reactive reactive curing groups thereof is about 0.8 to 1.2 times the equivalent number of epoxide groups in the epoxy resin. The organic gel additive may be contained in an amount of 0.1 to 60 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent. Such an epoxy resin composition may be used as an adhesive composition and may be a room temperature curing type adhesive composition.

[Chemical Formula 1]

In the above formula (1), Rs may be any of the compounds represented by the following general formula (2), regardless of each other.

(2)

In Formula 2, R ₁ , R ₂ , and R ₃ may be a linear alkyl group of C 2 -C 4, a branched alkyl group of C 3 -C 4, or a silyl group, independently of each other, n may be from 2 to 6, n + m may be from 2 to 12; In other words, R in the above formula (1) may be polyethylene oxide, polypropylene oxide, polybutylene oxide, polysiloxane, or a combination thereof regardless of each other. However, when R is polypropylene oxide, the tensile strength or modulus of the epoxy resin composition may be further improved as compared with other cases.

In another example, R in the formula (1) may be any of the compounds represented by the following formula (3), independently of each other.

(3)

In Formula 3, R ₁ and R ₃ may be a linear alkyl group of C 2 -C 4, a branched alkyl group of C 3 -C 4, or a silyl group, and n may be 2 to 6, regardless of each other. However, when R ₁ is a C3-C4 branched alkyl group, the tensile strength or modulus of the epoxy resin composition may be further improved as compared with other cases.

Specifically, in the above formula (1), Rs may be any one of the compounds represented by the following formulas (3a) to (3e).

[Chemical Formula 3]

(3b)

[Chemical Formula 3c]

(3d)

[Formula 3e]

In the above formulas 3a to 3e, n may be 2 to 6, and in Formula 3e, R 'and R " may be hydrogen or a C1-C4 alkyl group, regardless of each other.

The epoxy resin is a macromolecular compound containing two or more epoxy groups, and examples thereof include bisphenol A type epoxy resins, bisphenol F type epoxy resins and the like; Aminophenolic epoxy resins; Fluorene-based epoxy resin; Siloxane-based epoxy resins; Alicyclic epoxy resins; Or a hydrogenated bisphenol epoxy resin, for example, hydrogenated bisphenol A type epoxy resin or hydrogenated bisphenol F type epoxy resin. Of these, a hydrogenated bisphenol-based epoxy resin or an alicyclic epoxy resin in which sulfur-modified is suppressed can be used.

The curing agent may be a polyether polyamine having two or more amine groups bonded to a polyamine having two or more amine groups, specifically, a polyether backbone, or two or more cyclohexane polyamines in a cyclic nucleic acid backbone. The polyamine-based curing agent may be a diamine or a triamine. Such a curing agent enables curing at room temperature, and thus can be applied to an adhesive material which may be deteriorated by heat at a high temperature such as cultural property. Specifically, the curing agent may be polyethylene oxide diamine, polybutylene oxide diamine, polypropylene oxide diamine, cyclohexanediamine, or a combination thereof.

The cyclohexanediamine may be represented by the following general formula (4).

[Chemical Formula 4]

In the formula (4), R is an alkyl group of C1 to C3, L1 and L2 are independently C1 to C3 alkyl groups, n is an integer of 0 to 4, and m and l may be an integer of 0 to 2 .

Examples of the cyclohexanediamine include 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-cyclohexanediamine, 1,1-cyclohexanediamine, 4-methylcyclo Hexane-1,3-diamine, or 3-aminomethyl-3,5,5-trimethyl-cyclohexaneamine (isophorone diamine). As described above, when cyclohexanediamine is used as the curing agent, the tensile strength can be increased rather than decreased even when the organic gel additive is added.

The epoxy resin composition may further contain a solvent. In this case, the solvent may be contained in an amount of 0.01 to 10 parts by weight. The solvent may be a polar aprotic solvent, such as acetone or NMP (N-methyl pyrrolidone) having a carbonyl group. Such a polar aprotic solvent may induce hydrogen bonding of a hemiaminal group in the organic gel additive.

The epoxy resin composition may further contain 0.1 to 10 parts by weight of a diluent. The diluent may be an aliphatic glycidyl ether such as butyl glycidyl ether or 2-ethylhexyl glycidyl ether or an aromatic glycidyl ether such as phenyl glycidyl ether or O-cresyl glycidyl ether, But is not limited thereto.

The epoxy resin composition may further include 0.1 to 10 parts by weight of an inorganic filler. The inorganic filler may be at least one selected from the group consisting of calcium carbonate, talc, clay, and silica, but is not limited thereto.

Such an epoxy resin composition contains an organic gel additive having a network-bonded hemiaminal group as shown in Formula 1, and exhibits a self-healing property capable of reattaching after cutting, Decomposition through acid treatment may also be possible.

Method for producing epoxy resin composition

The organic gel additive shown in Formula 1 can be prepared.

The organic gel additive may be formed by heat treatment while mixing diamine, paraformaldehyde and a solvent represented by the following formula (5).

[Chemical Formula 5]

In Formula 5, R 1, R 2, and R 3 may be a linear alkyl group of C 2 -C 4, a branched alkyl group of C 3 -C 4, or a silyl group, independently of each other, n may be from 2 to 6, Lt; / RTI > Optionally, m may be zero. In other words, the diamines of formula (5) may be polyethylene oxide diamine, polypropylene oxide diamine, polybutylene oxide diamine, polysiloxane diamine, or combinations thereof. However, when polypropylene oxide diamine is used, the tensile strength or modulus of the epoxy resin composition described later can be further improved.

Specifically, the compound of formula (5) may be represented by the following formula (6).

[Chemical Formula 6]

In Formula 6, R ₁ and R ₃ may be a linear alkyl group of C 2 -C 4, a branched alkyl group of C 3 -C 4, or a silyl group, and n may be 2 to 6, regardless of each other. However, when R ₁ is a C3-C4 branched alkyl group, the tensile strength or modulus of the epoxy resin composition described later can be further improved.

 More specifically, the compound of formula (5) may be represented by the following formulas (6a) to (6e).

[Chemical Formula 6a]

[Formula 6b]

[Chemical Formula 6c]

[Chemical formula 6d]

[Formula 6e]

In the above formulas 6a to 6e, n may be 2 to 6, and in formula 6e, R 'and R " may be hydrogen or a C1-C4 alkyl group, regardless of each other.

The solvent may be polar aprotic solvents. The heat treatment may be performed at a temperature of about 20 to 100 degrees Celsius, specifically about 20 to 60 degrees Celsius degrees.

An epoxy resin, a curing agent, and the organic gel additive may be mixed to prepare an epoxy resin composition. At this time, the curing agent may be contained such that the equivalent number of the reactive curing unit thereof is about 0.8 to 1.2 times the equivalent number of epoxide groups in the epoxy resin. The organic gel additive may be contained in an amount of 0.1 to 60 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent.

Hereinafter, preferred examples will be given to facilitate understanding of the present invention. It should be understood, however, that the following examples are for the purpose of promoting understanding of the present invention and are not intended to limit the scope of the present invention.

≪ Organic gel additive preparation example 1 >

0.3 g of polypropylene oxide diamine (Jeff amine D230) and 0.097 g of paraformaldehyde (HCHO) were dissolved in 2 ml of NMP (N-methyl-2-pyrrolidone) and stirred at room temperature. After 24 hours of reaction, it was confirmed that a transparent organic gel was formed.

≪ Organic gel additive preparation example 2 >

0.3 g of polypropylene oxide diamine (Jeff amine D230) and 0.097 g of paraformaldehyde (HCHO) were dissolved in 2 ml of NMP and stirred at 50 캜. After 12 hours of reaction, it was confirmed that a transparent organic gel was formed.

≪ Organic gel additive preparation example 3 >

0.3 g of polyethylene oxide diamine having a molecular weight of 2000 and 0.02 g of paraformaldehyde (HCHO) were dissolved in 2 ml of NMP and stirred at 50 캜. After 12 hours of reaction, it was confirmed that a transparent organic gel was formed.

1 is a photograph showing an organic gel according to Production Examples 1 and 2 of Organic Gel Additives.

Referring to FIG. 1, the organic gels according to Preparation Examples 1 and 2 have a shape of transparent gel, and even if the vial containing the vials is arranged upside down, it can be seen that they do not flow down. On the other hand, the organic gel according to Production Example 3 had greater flow than the organic gels according to Production Examples 1 and 2. It was understood that this was due to the difference of the diamine compounds.

≪ Epoxy adhesive composition production examples 1 to 8 >

50.0 g of HBA (hydrogenated bisphenol A) epoxy resin and 12.6 g of Jeffamine D230 were placed in a container and stirred at 600 rpm for 10 minutes to prepare an adhesive. Here, the organic gel prepared according to Organic Gel Additive Preparation Example 1 was added as shown in Table 1 below, stirred for 10 minutes, and degassed in a vacuum oven for 10 minutes.

≪ Epoxy adhesive composition production examples 9 to 12 >

50.0 g of HBA (hydrogenated bisphenol A) epoxy resin and 9.35 g of IPDA (Isophonone diamine) were placed in a container and stirred at 600 rpm for 10 minutes to prepare an adhesive. Here, the organic gel prepared according to Organic Gel Additive Preparation Example 1 was added as shown in Table 1 below, stirred for 10 minutes, and degassed in a vacuum oven for 10 minutes.

≪ Epoxy adhesive composition Comparative Example 1 >

50.0 g of HBA (hydrogenated bisphenol A) epoxy resin and 12.6 g of Jeffamine D230 were placed in a container and stirred at 600 rpm for 10 minutes to prepare an adhesive composition.

≪ Epoxy adhesive composition Comparative Example 2 >

50.0 g of HBA (hydrogenated bisphenol A) epoxy resin and 9.35 g of IPDA (Isophonone diamine) were placed in a container and stirred at 600 rpm for 10 minutes to prepare an adhesive composition.

Epoxy adhesive
Composition Type of hardener Organic Gel Additive Content
(% By weight based on the total weight of epoxy resin and curing agent) Comparative Example 1 Jeff Amin D230
(Polypropylene oxide diamine) 0 g (0 wt%) Production Example 1 1.88 g (3 wt%) Production Example 2 3.76 g (6 wt%) Production Example 3 5.63 g (9 wt%) Production Example 4 7.51 g (12 wt%) Production Example 5 9.39 g (15 wt%) Production Example 6 18.78 g (30 wt%) Production Example 7 25.04 g (40 wt%) Production Example 8 31.31 g (50 wt%) Comparative Example 2 IPDA (Isophonone diamine) 0 g (0 wt%) Production Example 9 1.78 g (3 wt%) Production Example 10 5.34 g (9 wt%) Production Example 11 8.90 g (15 wt%) Production Example 12 12.46 g (21 wt%)

2 is a graph showing the viscosity of the epoxy adhesive compositions according to Comparative Example 2 and Production Examples 9 to 12.

Referring to FIG. 2, it can be seen that the viscosity decreases as the organic gel is added. Such reduction of the viscosity facilitates penetration of the adhesive into the inside of the adhering material, which can lead to an improvement in adhesion strength.

<Experimental Example for Confirmation of Self-Healing>

Epoxy Adhesive Compositions Each epoxy adhesive composition obtained through the preparation examples was poured into a silicone mold to produce adhesive rods. At this time, in each production example, a colorless adhesive rod containing no dye and an adhesive rod containing a red dye were prepared. A colorless adhesive rod and a red adhesive rod obtained through the above epoxy adhesive rod preparation example 3 were cut to a length of 1 cm each after 5 days of manufacture, fixed with a predetermined pressure so as to be in contact with each other, and then heat-treated at room temperature and 50 ° C for 2 hours.

FIGS. 3A and 3B are photographs showing a self-healing confirmation experiment process.

3A and 3B, after epoxy adhesive rods obtained through Epoxy Adhesive Rod Production Example 3 were cut, they were fixed with a predetermined pressure so as to contact the cut rods, and then heat-treated at room temperature (FIG. 3A) It can be seen that the bars cut in all cases (Fig. 3B) were again bonded. However, the epoxy adhesive rods obtained through the epoxy adhesive rod Comparative Example 1 were not re-adhered. From this, it can be seen that the epoxy adhesive composition of the present invention has a self-healing property that can be re-adhered by containing an organic gel additive having network-bonded hemiamyl groups.

<Tensile strength test example of epoxy adhesive film>

A stainless steel panel having a size of 130 x 25.4 x 2 mm was prepared and the adhesive side was sanded with 60 times. Thereafter, the adhesive compositions according to Production Examples 1 to 12 and Comparative Examples 1 and 2 were applied on the adhesive surface with a width of 25.4 mm, a length of 13 mm, and a thickness of 0.2 mm to form an adhesive film, The tensile strength was measured at a rate of 2 mm / min.

4 is a graph showing the tensile strengths of the adhesive films formed using the adhesive compositions according to Comparative Example 1 and Production Examples 1 to 8. Fig.

Referring to FIG. 4, when the organic gel is contained in the adhesive composition, the tensile strength is reduced. However, when the organic gel is contained in an amount of 12 wt% or more, no further decrease in tensile strength is exhibited.

Fig. 5 is a graph showing the tensile strengths of the adhesive films formed using the adhesive compositions according to Comparative Example 2 and Production Examples 9 to 12. Fig.

Referring to FIG. 5, it can be seen that the tensile strength is increased when the organic gel is contained in the adhesive composition.

4 and 5, the adhesive compositions according to Production Examples 9 to 12, that is, the adhesive compositions using IPDA (diamine with a backbone of cyclohexane) as a curing agent, were prepared according to Production Examples 1 to 8 Compared to adhesive compositions using adhesive compositions, that is, polypropylene diamine curing agents as curing agents, it has been found that tensile strength is increased even when an organic gel is added. From this, it can be seen that when a diamine curing agent using cyclohexane as a backbone is used, Were expected to be better.

&Lt; Experimental Example of Tensile Strength after Self-Healing of Epoxy Adhesive Film &

Tensile Strength of Epoxy Adhesive Film The epoxy adhesive film was removed from a stainless steel panel in the test pieces after the experiment, and heat-treated at room temperature for 2 days while being fixed with a predetermined pressure so that the two were in contact with each other. The tensile strength was measured at a rate of 2 mm / min.

FIG. 6 is a graph showing tensile strengths before and after re-bonding of the adhesive films formed using the adhesive compositions according to Production Examples 1 to 5. FIG.

Referring to FIG. 6, it can be seen that the tensile strength after re-bonding is slightly lower than that before re-bonding, but still shows a significant value of tensile strength. On the other hand, in the case of the adhesive film formed using the adhesive composition of Comparative Example 1 containing no organic gel, no adhesive force was observed after the re-bonding treatment.

FIG. 7 is a graph showing tensile strengths before and after re-bonding of the adhesive films formed using the adhesive compositions according to Production Examples 10 and 11. FIG.

Referring to FIG. 7, it can be seen that the tensile strength after re-bonding is somewhat lower than before re-bonding, but still shows a significant value of tensile strength. On the other hand, in the case of the adhesive film formed using the adhesive composition according to Comparative Example 2 containing no organic gel, no adhesive force was observed after the re-bonding treatment.

&Lt; Experimental Example of Epoxy Adhesive Film Disassembly &

A film having a thickness of 1.18 mm was prepared using the epoxy adhesive composition according to Production Example 3, and the film was immersed in a 0.5 M aqueous sulfuric acid solution for 30 days.

8 is a photograph taken during the progress of the epoxy adhesive film decomposition experiment example.

8, the film using the epoxy adhesive composition according to Preparation Example 3 containing 9 wt% of organic gel was damaged in the surface and inside of the sample after being dipped in a 0.5 M sulfuric acid aqueous solution for 24 hours, and the thickness thereof was 1.44 mm 22% swelling, indicating decomposition characteristics. After 30 days, the adhesive film was completely decomposed by ultrasonic treatment. From this, it can be seen that the adhesive composition containing an organic gel can be decomposed by acid treatment.

Claims (7)

An organic gel additive comprising an epoxy resin, a curing agent, and network-bonded hemicyclic groups represented by the following formula (1)
Wherein the curing agent is cyclohexanediamine represented by the following general formula (4), the equivalent number of reactive reactive curing groups is 0.8 to 1.2 times the equivalent number of epoxide groups in the epoxy resin,
Wherein the organic gel additive is contained in an amount of 0.1 to 60 parts by weight based on 100 parts by weight of the total amount of the epoxy resin and the curing agent,
[Chemical Formula 1]

In the above formula (1), R is any one of the compounds represented by the following formulas (3c) and (3d) independently of each other,
[Chemical Formula 3c]

(3d)

In the above formulas 3c and 3d, n is 2 to 6,
[Chemical Formula 4]

In the formula (4), R is an alkyl group of C1 to C3, L1 and L2 are independently C1 to C3 alkyl groups, n is an integer of 0 to 4, and m and l are integers of 0 to 2, The method according to claim 1,
0.01 to 10 parts by weight of a polar aprotic solvent. 3. The method of claim 2,
Wherein the polar aprotic solvent is acetone or NMP (N-methyl pyrrolidone). Forming an organic gel by mixing at least one of the compounds represented by the following formulas (6c) and (6d) with diamine, paraformaldehyde, and a solvent; And
And mixing the organic gel, the epoxy resin, and the cyclohexanediamine of the following formula (4):
[Chemical Formula 6c]

[Chemical formula 6d]

In the above formulas 6c and 6d, n is 2 to 6,
[Chemical Formula 4]

In the formula (4), R is an alkyl group of C1 to C3, L1 and L2 are independently C1 to C3 alkyl groups, n is an integer of 0 to 4, and m and l are integers of 0 to 2, 5. The method of claim 4,
Wherein the solvent is a polar aprotic solvent. 6. The method of claim 5,
Wherein the polar aprotic solvent is acetone or NMP (N-methyl pyrrolidone). 5. The method of claim 4,
Wherein the mixing in the step of forming the organic gel is performed at a temperature of 20 to 60 degrees Celsius.

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