KR20160010109A - Thermoreversible elastomers and the method for preparation of the same - Google Patents

Abstract

The present invention provides a heat reversible elastic body where one or more selected from the group consisting of maleic anhydride, maleic acid, and maleic acid derivative comprise a monomer of grafted synthetic rubber, and an ion bond and a covalent bond between the monomers of the synthetic rubber are formed at the same time. The heat reversible elastic body according to the present invention has excellent physical properties because the ion bond and the covalent bond between the monomers of the synthetic rubber are formed at the same time, and shows heat reversible properties at the low temperature. Thus, the heat reversible elastic body according to the present invention has a reusable effect due to a reversible reaction by heat.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoreversible elastomer and a thermoreversible elastomer,

The present invention relates to a thermoreversible elastomer and a method of manufacturing the same, and more particularly, to a thermoreversible elastomer in which ionic bonds and covalent bonds are simultaneously formed between monomer units of a synthetic rubber and a method for producing the same.

Generally, rubber has the elasticity to return to the original state when the shape and volume are deformed by the external force and then the force is removed. The elasticity of the rubber gradually increases the force, In order to increase the limit of permanent deformation and improve the mechanical properties, crosslinking of the network structure is formed by using a crosslinking agent such as sulfur or organic peroxide in the rubber composition. However, the crosslinked rubber composition exhibits thermosetting and has a disadvantage that it can not be recycled.

Conventional rubber recycling means that the molecular structure of the rubber compound is retreated and the rubber that is cured is not melted again due to the nature of the crosslinked rubber. Therefore, it is not possible to recycle the old rubber because it is newly re- It was merely to be recycled to the extent that it was pulverized into powder and then mixed with new rubber.

Therefore, in order to overcome the disadvantages of such a rubber composition, a thermoplastic elastomer (TPE) having elasticity, which is characteristic of rubber by physical agglomeration of hard segment at room temperature, and physical aggregation is melted at high temperature, ) Has been developed and used in rubber applications. Recently, environmental issues have been highlighted most in society and industry, and research and development to replace rubber with thermoplastic elastomer material have been progressing actively and application fields are gradually expanding.

The thermoplastic elastomer is advantageous in that it has high productivity because it has no complicated crosslinking process due to its thermoplasticity and can be used without modification of the existing plastic processing apparatus. On the other hand, compared with the conventional crosslinked rubber having a chemical crosslinking structure, the heat resistance, durability, Strain, elastic restoring force, and scratch resistance are lowered, and residual strain is large, which causes stress relaxation and creep phenomenon. Thermoplastic vulcanizates (TPV), developed to overcome these shortcomings, are blends of soft rubber and hard plastic, but they are materials that exhibit resilience similar to conventional thermosetting rubber due to the cross-linking of soft rubber parts, Plasticity (PP) or polyethylene (PE), which is mainly used for the plasticizer (PE), the filling rate of the filler is low similarly to that of the general plastic, so that it is difficult to increase the content by 30 wt% or more and has a disadvantage that the scratch resistance is poor .

As a method for solving the above problems, a thermally reversible elastomer has been developed. As an example of such a thermally reversible elastomer, MAJ van der Mee et al. A thermally reversible crosslinked maleated ethylene / propylene rubber in which the maleic anhydride and the olefin resin are grafted has been disclosed (rubber chemistry and technology, 81, 96, 2007). However, as described above, hydrogen bonding or ionic interaction has a problem in that the thermally reversible elastomer produced has insufficient physical properties or exhibits thermoreversible properties at high temperatures.

Accordingly, the inventors of the present invention have been studying thermoreversible elastomers having excellent physical properties and thermoreversible properties at low temperatures, and have found that when a maleic anhydride, a maleic acid, and a maleic acid derivative in which at least one of maleic acid derivatives are grafted A thermally reversible elastomer in which ionic bonds and covalent bonds are simultaneously formed between monomer units of rubber has been developed and the present invention has been completed.

It is an object of the present invention to provide a thermo-reversible elastomer and a method of manufacturing the same.

In order to achieve the above object,

At least one monomer selected from the group consisting of maleic anhydride, maleic acid and maleic acid derivatives is grafted,

And a thermally reversible elastomer characterized in that an ionic bond and a covalent bond are simultaneously formed between the monomer units of the synthetic rubber.

In addition,

Preparing a maleic anhydride grafted synthetic rubber (step 1);

Mixing the maleic anhydride grafted synthetic rubber prepared in the step 1 with a metal salt and a secondary alcohol or a tertiary alcohol to prepare a mixture (step 2); And

And stirring the mixture prepared in step 2 to form an ionic bond and a covalent bond between synthetic rubber molecules (step 3).

Further,

There is provided an automobile rubber component comprising the above-mentioned thermally reversible elastomer.

The thermally reversible elastomer according to the present invention has an effect of simultaneously forming ionic bonds and covalent bonds between synthetic rubber units and thus exhibiting excellent physical properties and exhibiting thermoreversible properties at low temperatures. As described above, the thermo-reversible elastomer according to the present invention exhibits a reversible reaction by heat, so that it is reusable.

1 is a graph showing the results of differential scanning calorimetry (DSC) analysis of thermally reversible elastomer and maleic anhydride grafted isobutylene-isoprene rubber prepared in Example 1 and Comparative Examples 1 to 4 according to the present invention ego;
2 to 5 are graphs showing the results of analysis of the thermally reversible elastomer and maleic anhydride-grafted isobutylene-isoprene rubber prepared in Example 1 and Comparative Examples 1 to 4 according to the present invention by a universal testing machine (UTM) ego;
Figs. 6 to 9 are graphs of the thermally reversible elastomers prepared in Example 1 and Comparative Examples 2 to 4 according to the present invention by infrared spectroscopy (FT-IR).

The present invention

At least one monomer selected from the group consisting of maleic anhydride, maleic acid and maleic acid derivatives is grafted,

And a thermally reversible elastomer characterized in that an ionic bond and a covalent bond are simultaneously formed between the monomer units of the synthetic rubber.

Hereinafter, the thermo-reversible elastomer according to the present invention will be described in detail.

In the thermo-reversible elastomer according to the present invention, the thermo-reversible elastomer is a synthetic rubber monomer unit in which at least one member selected from the group consisting of maleic anhydride, maleic acid and maleic acid derivatives is grafted . ≪ / RTI >

The synthetic rubber may be an isobutylene-isoprene rubber, an ethylene-propylene rubber, an isoprene rubber, a butadiene rubber, a styrene-butadiene rubber, a nitrile rubber or the like, but is not limited thereto. Preferably, it may be an isobutylene-isoprene rubber having excellent gas barrier properties and being used in vibration-damping rubbers and the like.

In the thermally reversible elastomer according to the present invention, the thermally reversible elastomer is characterized in that ionic bonds and covalent bonds are simultaneously formed between the units of the synthetic rubber.

The ionic bond and the covalent bond are simultaneously formed between the units of the synthetic rubber contained in the thermo-reversible elastomer, thereby exhibiting thermoreversible characteristics at a low temperature of 150 ° C or less while maintaining excellent physical properties. Preferably, the thermo-reversible elastomer may exhibit thermoreversible properties at a temperature of 50 to 150 ° C. When the rubber product containing the thermoreversible elastomer is recycled by exhibiting the thermoreversible characteristic at low temperature as described above, the energy consumption is small and it is economical.

In addition,

Preparing a maleic anhydride grafted synthetic rubber (step 1);

Mixing the maleic anhydride grafted synthetic rubber prepared in the step 1 with a metal salt and a secondary alcohol or a tertiary alcohol to prepare a mixture (step 2); And

And stirring the mixture prepared in step 2 to form an ionic bond and a covalent bond between synthetic rubber molecules (step 3).

Hereinafter, the method for producing thermo-reversible elastomer according to the present invention will be described in detail for each step.

First, in the method for producing a thermally reversible elastomer according to the present invention, step 1 is a step of preparing a maleic anhydride grafted synthetic rubber.

Step 1 is a step of grafting maleic anhydride so as to form a site which is polarized in the synthetic rubber and can have ionic bonds and covalent bonds.

Specifically, the synthetic rubber of step 1 may be an isobutylene-isoprene rubber, an ethylene-propylene rubber, an isoprene rubber, a butadiene rubber, a styrene-butadiene rubber or a nitrile rubber, As the rubber, an isobutylene-isoprene rubber excellent in gas barrier property and used for vibration proof rubber can be used.

Further, the step of preparing the maleic anhydride grafted synthetic rubber of the step 1 is, for example,

Dissolving the synthetic rubber in a solvent to prepare a synthetic rubber solution (step a); And

Mixing the maleic anhydride and dibenzoyl peroxide in the synthetic rubber solution prepared in step a), and heating the mixture to a temperature of 80 to 100 ° C (step b).

The step (a) is a step of dissolving synthetic rubber in a solvent to prepare a synthetic rubber solution.

Specifically, in step a, a synthetic rubber solution is prepared by dissolving synthetic rubber in a non-polar solvent such as toluene.

The step (b) is a step of mixing maleic anhydride and dibenzoyl peroxide into the synthetic rubber solution prepared in the step (a) and heating the mixture to a temperature of 80 to 100 ° C.

The step b is a step of mixing dibenzoyl peroxide as an auxiliary agent for reaction with maleic anhydride to be grafted in the synthetic rubber solution prepared in step a, heating the mixture at a temperature of 80 to 100 占 폚, And grafting the anhydride.

In this case, the heating in step b is preferably carried out for at least one day, particularly preferably for at least three days, and for a time of from 1 to 10 days. It is preferable that the maleic anhydride is grafted to the synthetic rubber by reacting for a sufficient time as described above.

Also, after step b) is performed to graft the maleic anhydride to the synthetic rubber, the solution can be solidified by drying under vacuum conditions at a temperature of 20 to 60 ° C for 12 to 48 hours.

Next, in the method for producing thermo-reversible elastomer according to the present invention, Step 2 is a step of mixing the maleic anhydride grafted synthetic rubber prepared in Step 1 with a metal salt and a secondary alcohol or a tertiary alcohol to prepare a mixture .

Specifically, the metal salt of step 2 may be potassium hydroxide (KOH). The secondary alcohol in the step 2 may be ethylene glycol. Further, the tertiary alcohol in step 2 may be glycerol. However, the metal salt of the step 2 and the secondary alcohol or the tertiary alcohol may be formed by ring-opening the maleic anhydride of the maleic anhydride-grafted synthetic rubber, thereby simultaneously showing the ionic bond and the covalent bond But the present invention is not limited thereto.

In addition, the mixture of step 2 may further include a solvent such as toluene, methanol, 2-propanol, acetone, ethanol and cyclohexane. By way of example, the mixture of step 2 may further comprise a solvent in which toluene and 2-propanol are mixed.

Next, in the method for producing a thermally reversible elastomer according to the present invention, Step 3 is a step of stirring the mixture prepared in Step 2 to form an ionic bond and a covalent bond between the synthetic rubber units.

In the step 3, the mixture prepared by mixing the maleic anhydride grafted synthetic rubber with the metal salt and the secondary alcohol or the tertiary alcohol in the step 2 is stirred to form ionic bonds and covalent bonds between the synthetic rubber units . At this time, the position where the maleic anhydride grafted synthetic rubber and the metal salt can react with each other to form an ionic bond can be obtained, and the maleic anhydride grafted synthetic rubber is reacted with the secondary alcohol or the tertiary alcohol To obtain a position at which a covalent bond can be formed.

Thus, by forming ionic bonds and covalent bonds at the same time between the synthetic rubber units, excellent physical properties can be maintained and thermoreversible properties can be exhibited at a low temperature of 150 DEG C or lower.

Specifically, the stirring of step 3 is preferably carried out at a rotation speed of 50 to 150 rpm. If the stirring of the step 3 is carried out at a rotational speed of less than 50 rpm, the mixture does not form a uniform reaction and thus the physical properties are insufficient. When the stirring is carried out at a rotational speed exceeding 150 rpm There is a problem that the bonding between the synthetic rubber units is very strongly formed and the thermoreversible characteristics are hardly exhibited.

As a specific example, when the synthetic rubber is isobutylene-isoprene rubber in the step 3, the metal salt is potassium hydroxide (KOH), and the tertiary alcohol is glycerol, Bond and covalent bond.

≪ Formula 1 >

When the maleic anhydride-grafted isobutylene-isoprene rubber is mixed with glycerol, which is a tertiary alcohol, and potassium hydroxide, which is a metal salt, as shown in Formula 1, the thermal reversibility An elastic body can be produced. Thus, by forming ionic bonds and covalent bonds at the same time between the synthetic rubber units, excellent physical properties can be maintained and thermoreversible properties can be exhibited at a low temperature of 150 DEG C or lower.

Further,

There is provided an automobile rubber component comprising the above-mentioned thermally reversible elastomer.

The automobile rubber component comprising the thermo-reversible elastomer according to the present invention exhibits excellent properties including thermally reversible elastomers which exhibit excellent physical properties and simultaneously exhibit thermoreversible properties at low temperatures since ionic bonds and covalent bonds are simultaneously formed between the synthetic rubber units . As described above, the thermo-reversible elastomer according to the present invention exhibits a reversible reaction by heat, so that it is reusable.

Example 1 Preparation of thermally reversible elastomer 1

Step 1: A synthetic rubber solution was prepared by completely dissolving 5 g of isobutylene-isoprene rubber (IIR) in 50 ml of toluene.

The synthetic rubber solution was mixed with maleic anhydride and dibenzoyl peroxide and heated to a temperature of 92 캜 for 3 days.

Thereafter, the solution was dried in a vacuum oven at 40 DEG C for 24 hours to solidify and prepare maleic anhydride-grafted isobutylene-isoprene rubber (MA-g-IIR).

Step 2: 5 g of the maleic anhydride-grafted isobutylene-isoprene rubber prepared in the step 1 was dissolved in a solvent mixture of 25 ml of toluene and 25 ml of 2-propanol, (glycerol) and potassium hydroxide (KOH) were added to prepare a mixture.

Step 3: The mixture prepared in step 2 was stirred at a temperature of 65 DEG C at a rotation speed of 60 rpm for 25 minutes, dried at room temperature for 3 hours or more under a nitrogen atmosphere, and then dried at 60 DEG C for one day Thermally reversible elastomers having ionic bonds and covalent bonds were prepared.

≪ Comparative Example 1 &

A synthetic rubber solution was prepared by completely dissolving 5 g of isobutylene-isoprene rubber (IIR) in 50 ml of toluene.

The synthetic rubber solution was mixed with maleic anhydride and dibenzoyl peroxide and heated to a temperature of 92 캜 for 3 days.

Thereafter, the solution was dried in a vacuum oven at 40 DEG C for 24 hours to solidify and prepare maleic anhydride-grafted isobutylene-isoprene rubber (MA-g-IIR).

≪ Comparative Example 2 &

Step 1: A synthetic rubber solution was prepared by completely dissolving 5 g of isobutylene-isoprene rubber (IIR) in 50 ml of toluene.

The synthetic rubber solution was mixed with maleic anhydride and dibenzoyl peroxide and heated to a temperature of 92 캜 for 3 days.

Thereafter, the solution was dried in a vacuum oven at 40 DEG C for 24 hours to solidify and prepare maleic anhydride-grafted isobutylene-isoprene rubber (MA-g-IIR).

Step 2: 10 g of the maleic anhydride-grafted isobutylene-isoprene rubber prepared in the step 1 was dissolved in 150 ml of toluene, and then 3-amino-1,2,4-triazole -1,2,4-triazole, ATA) and tetrabutyl ammonium bromide (TBAB) were added to prepare a mixture.

Step 3: The mixture prepared in step 2 was stirred at a rotation speed of 60 rpm for 240 minutes, dried under a nitrogen atmosphere for one day at room temperature, and then dried at 60 DEG C for a day to form a thermally reversible elastomer .

≪ Comparative Example 3 &

Step 1: A synthetic rubber solution was prepared by completely dissolving 5 g of isobutylene-isoprene rubber (IIR) in 50 ml of toluene.

The synthetic rubber solution was mixed with maleic anhydride and dibenzoyl peroxide and heated to a temperature of 92 캜 for 3 days.

Thereafter, the solution was dried in a vacuum oven at 40 DEG C for 24 hours to solidify and prepare maleic anhydride-grafted isobutylene-isoprene rubber (MA-IIR).

Step 2: 10 g of the maleic anhydride-grafted isobutylene-isoprene rubber prepared in the above step 1 was added to a mixed solvent of 90 ml of toluene at 80 ° C and 10 ml of 2-propanol After dissolution, potassium hydroxide (KOH) was added to prepare a mixture.

Step 3: The mixture prepared in step 2 was stirred at a temperature of 80 DEG C at a rotation speed of 60 rpm for 25 minutes, dried at a temperature of 40 DEG C for 3 hours or more under a nitrogen atmosphere, To produce a thermally reversible elastomer having an ionic bond.

≪ Comparative Example 4 &

Step 1: A synthetic rubber solution was prepared by completely dissolving 5 g of isobutylene-isoprene rubber (IIR) in 50 ml of toluene.

The synthetic rubber solution was mixed with maleic anhydride and dibenzoyl peroxide and heated to a temperature of 92 캜 for 3 days.

Thereafter, the solution was dried in a vacuum oven at 40 DEG C for 24 hours to solidify and prepare maleic anhydride-grafted isobutylene-isoprene rubber (MA-g-IIR).

Step 2: 5 g of the maleic anhydride-grafted isobutylene-isoprene rubber prepared in the step 1 was dissolved in a solvent mixture of 25 ml of toluene and 25 ml of 2-propanol, (glycerol) was added to prepare a mixture.

Step 3: The mixture prepared in step 2 was stirred at a rotation speed of 60 rpm for 25 minutes, dried under a nitrogen atmosphere for one day at room temperature and then dried at 60 DEG C for one day to form a thermally reversible elastomer .

Experimental Example 1 Differential scanning calorimetry (DSC) analysis

In order to analyze the characteristics of the thermo-reversible elastomer according to the present invention, the thermally reversible elastomer and maleic anhydride-grafted isobutylene-isoprene rubber prepared in Example 1 and Comparative Examples 1 to 4 (MA-g -IIR) was analyzed by differential scanning calorimetry (DSC). The results are shown in FIG.

As shown in FIG. 1, the MAn-g-IIR of Comparative Example 1, which is merely grafted with maleic anhydride only, has a glass transition temperature (T _g ) of about 65 ° C., it can be confirmed that the glass transition temperature of Comparative Examples 2 to 4 and Example 1, which are heat-reversible elastomers formed with bonding, ionic bonding, covalent bonding, ionic bonding and covalent bonding, . It can be seen that this is a phenomenon caused by each combination. In the case of MAn-g-IIR of Comparative Example 1, which is merely grafted with maleic anhydride only, the glass transition temperature is low, but when it is heated, reversible reaction hardly occurs and physical properties are very weak.

In the case of Comparative Example 2, which is a thermally reversible elastomer formed with hydrogen bonds, it can be seen that the peak generated at around 186 ° C is due to multiple hydrogen bonding. In addition, in the case of Comparative Example 3, which is a thermally reversible elastomer formed with ionic bonds, the peak generated at a temperature of 170 캜 was found by ion dissociation, and in Comparative Example 4, which was a covalent bond formed thermally reversible elastomer, 179 캜 A peak occurring near the temperature means that the covalent bond is cleaved. Furthermore, in the case of Example 1, which is a thermally reversible elastomer in which ionic bonds and covalent bonds are simultaneously formed, an endothermic peak is generated at a temperature of 126 ° C and a temperature of 146 ° C, where ionic bonds and covalent bonds are broken.

As a result, it can be seen that the thermo-reversible elastomer in which the ionic bond and the covalent bond are formed simultaneously according to the present invention exhibits thermoreversible properties at a relatively low temperature.

<Experimental Example 2> Analysis of physical properties according to the recycle cycle

In order to analyze the physical properties of the thermo-reversible elastomer according to the recycling cycle of the present invention, the heat-reversible elastomer and maleic anhydride-grafted isobutylene-isoprene rubber prepared in Example 1 and Comparative Examples 1 to 4 (MA-g-IIR) was analyzed with a universal testing machine (UTM), and the results are shown in Figs. 2 to 5. Fig.

At this time, the thermo-reversible elastomer produced in Example 1 and Comparative Examples 2 to 4 was heated up to a temperature at which thermoreversible characteristics were exhibited in a recycle cycle, held for 30 minutes, cooled to room temperature, The tensile strength was measured in each case.

As shown in FIGS. 2 to 5, the thermally reversible elastomers prepared in Example 1 and Comparative Examples 2 to 4 exhibited significantly increased tensile strengths as compared with the MA-g-IIR prepared in Comparative Example 1. In addition, the thermally reversible elastomer prepared in Example 1 and Comparative Examples 2 to 4 had a tensile strength slightly lower than that of MA-g-IIR prepared in Comparative Example 1, . &Lt; / RTI &gt;

Further, in the case of the thermally reversible elastomer of Example 1 in which both the ionic bond and the covalent bond were simultaneously formed, it was confirmed that the thermally reversible elastomer exhibited thermo-reversibility at a temperature of 140 ° C or lower, which is 150 ° C or less.

As described above, when the rubber is recycled and used at a temperature of 150 ° C or lower, the rubber can be reduced in energy consumption and can be used as an industrial rubber because it can exhibit sufficient physical properties even when it is recycled.

Experimental Example 3 Infrared spectroscopic analysis

In order to confirm the thermoreversible characteristics of the thermo-reversible elastomer according to the present invention, the thermo-reversible elastomers prepared in Example 1 and Comparative Examples 2 to 4 were analyzed by infrared spectroscopy (Fourier transform infrared spectroscopy) 6 to 9.

At this time, as in Experimental Example 2, up to 3 cycles were performed and analyzed by infrared spectroscopy.

As shown in FIGS. 6 to 9, the thermally reversible elastomer prepared in Example 1 and Comparative Examples 2 to 4 showed that the molecular structure and the functional groups were not changed during heating and cooling. Upon heating, each bond was released, and upon cooling, each bond was formed again, thereby confirming the thermoreversible characteristics.

Claims (14)

At least one monomer selected from the group consisting of maleic anhydride, maleic acid and maleic acid derivatives is grafted,
Characterized in that ionic bonding and covalent bonding are simultaneously formed between the unit pieces of the synthetic rubber.
The method according to claim 1,
Wherein the synthetic rubber is one kind selected from the group consisting of isobutylene-isoprene rubber, ethylene-propylene rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber and nitrile rubber.
The method according to claim 1,
Wherein the synthetic rubber is an isobutylene-isoprene rubber.
The method according to claim 1,
Wherein the thermo-reversible elastomer exhibits thermoreversible properties at a temperature of 50 to 150 ° C.
Preparing a maleic anhydride grafted synthetic rubber (step 1);
Mixing the maleic anhydride grafted synthetic rubber prepared in the step 1 with a metal salt and a secondary alcohol or a tertiary alcohol to prepare a mixture (step 2); And
And stirring the mixture prepared in step 2 to form an ionic bond and a covalent bond between the synthetic rubber units (step 3).
6. The method of claim 5,
Wherein the synthetic rubber of step 1 is one kind selected from the group consisting of isobutylene-isoprene rubber, ethylene-propylene rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber and nitrile rubber .
6. The method of claim 5,
Wherein preparing the maleic anhydride grafted synthetic rubber of step 1 comprises:
Dissolving the synthetic rubber in a solvent to prepare a synthetic rubber solution (step a); And
Mixing the maleic anhydride and dibenzoyl peroxide in the synthetic rubber solution prepared in step a) and heating the mixture to a temperature of 80 to 100 ° C (step b) A method for producing thermally reversible elastomers.
8. The method of claim 7,
Wherein the heating in step b) is carried out for a period of time of from 1 to 5 days.
6. The method of claim 5,
Wherein the metal salt of step 2 is potassium hydroxide (KOH).
6. The method of claim 5,
Wherein the secondary alcohol in step 2 is ethylene glycol.
6. The method of claim 5,
Wherein the tertiary alcohol of step 2 is glycerol. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
6. The method of claim 5,
Wherein the mixture of step 2 comprises at least one solvent selected from the group consisting of toluene, methanol, 2-propanol, acetone, ethanol and cyclohexane.
6. The method of claim 5,
Wherein the stirring of step 3 is performed at a rotation speed of 50 to 150 rpm.
An automotive rubber part comprising the thermo-reversible elastomer of claim 1.

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