WO2022169317A1 - High-strength self-healing polyurethane polymer having room-temperature self-healing function - Google Patents

Abstract

The present invention relates to a self-healing polyurethane polymer having both high tensile strength and a high self-healing effect even at room temperature. Specifically, the present invention relates to a self-healing polyurethane polymer comprising structural units derived from aliphatic polycarbonate-based polyols, cycloaliphatic polyisocyanates, and aliphatic disulfide-based polyols.

Description

High-strength self-healing polyurethane polymer with room temperature self-healing function

The present invention relates to a transparent polyurethane polymer having high tensile strength and high self-healing efficiency at room temperature and a method for preparing the same.

Unlike biological materials that can repeatedly recover from physical damage caused by external forces, artificially manufactured polymer products have a limited lifespan because they cause irreversible fracture due to accumulated physical damage or cracks.

In particular, among the products made of the polymer, in the case of a protective material or a portable device product that is repeatedly exposed to external stress, there is a problem in that durability and product life are shortened due to an increase in fatigue due to an external force.

Accordingly, in the prior art, research on a self-healing polymer material that is inspired by a biological tissue is being conducted. The development of the self-healing polymer material can be mainly used for protective coatings used in automobile parts, electronic products, and medical devices.

Among various polymer materials, thermoplastic urethane-based elastomer (TPU) has attracted much attention as a self-healing material due to its excellent mechanical and optical performance.

However, there are several problems in order to manufacture the self-healing TPU.

First, it is difficult to balance material performance, and secondly, there is the complexity of molecular design. The trade-off between mechanical and healing properties is the biggest obstacle to the problem of balancing the performance. Mechanical strength requires a dense and well-organized internal structure based on high crystallinity, strong secondary bonds and/or high chain stiffness, but such a polymeric structure inevitably interferes with chain mobility and the corresponding self-healing ability.

Since these high crystallinity and chain mobility are mutually conflicting physical properties, it was difficult to simultaneously satisfy excellent mechanical properties and self-healing properties in the field of self-healing polymers. In particular, in the approach to self-healing TPU, for example, a disulfide group having dynamic covalent bonding properties was trapped in a crystalline hard domain, so that the desired self-healing function could not be sufficiently expressed.

In addition, performance balance must be realized without sacrificing TPU's inherent optical properties such as colorlessness and transparency.

In addition, in order to solve the problems related to molecular design, many strategies based on dynamic physical and chemical bonding have been proposed to make breakthroughs that break the balance of performance. However, complex synthetic procedures and complex molecular structures reduce processability and cost-effectiveness. Instead of designing complex chemical structures, modulation of TPU's hard domains and their microstructures can be in the spotlight as a simple and convenient approach.

Therefore, the present invention is to develop a self-healing high-strength polyurethane polymer that solves the above problems, that is, has high mechanical properties, has excellent self-healing power at room temperature, has excellent optical properties, and can be manufactured with a simple design.

The problem of conventional self-healing polymers is that the mechanical properties decrease as the self-healing properties are improved. To provide a urethane polymer.

In particular, the self-healing temperature of the existing polyurethane material having an aliphatic disulfide requires a temperature of 70° C. or higher, but in the present invention, it was discovered for the first time that self-healing is possible even at room temperature by changing the surrounding polymer structure design.

In order to solve the above problems, the present invention provides a self-healing polyurethane polymer comprising a structural unit derived from an aliphatic polycarbonate-based polyol, an alicyclic polyisocyanate, and an aliphatic disulfide-based polyol.

According to one aspect of the present invention, the self-healing polyurethane polymer may be a polyurethane prepolymer derived from an aliphatic polycarbonate-based polyol and an alicyclic polyisocyanate and an aliphatic disulfide-based polyol connected by a coupling.

According to one aspect of the present invention, the aliphatic polycarbonate-based polyol may have a number average molecular weight of 300 to 10,000 g/mol, preferably 500 to 5,000 g/mol.

According to an aspect of the present invention, the carbon number of the alkylene group of the structural unit of the aliphatic polycarbonate-based polyol may be 4 to 10.

According to an aspect of the present invention, the structural unit of the aliphatic disulfide-based polyol may have 4 to 10 carbon atoms.

According to an aspect of the present invention, the aliphatic polycarbonate-based polyol and the aliphatic disulfide-based polyol may be in a molar ratio of 1: 0.02 to 1.5.

According to an aspect of the present invention, the aliphatic polycarbonate-based polyol and the cycloaliphatic polyisocyanate are 1: 1.5 to 2.5 equivalent ratio of polyurethane prepolymer, and the equivalent ratio of the isocyanate group of the polyurethane prepolymer and the hydroxyl group of the aliphatic disulfide-based polyol is 1 : It may be 0.5 to 1.5.

According to one aspect of the present invention, the self-healing polyurethane polymer may have a tensile strength of 40 MPa or more and a tensile toughness of 50 MJ/m 3 or more.

According to an aspect of the present invention, the self-healing rate at 25° C., 72 hrs may be 40% or more, and the self-healing rate at 35° C., 72 hrs may be 80% or more.

Another aspect of the present invention may provide a porous self-healing polyurethane article comprising a self-healing polyurethane polymer.

The present invention can provide a self-healing polyurethane polymer having excellent mechanical strength of a certain strength or higher, which cannot be achieved due to the contradictory properties of the existing polyurethane polymers, and at the same time having an excellent self-healing effect even at low temperature or room temperature.

The present invention will be described in more detail through the following specific examples or examples. However, the following specific examples or examples are only a reference for describing the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Also, unless 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 for the purpose of effectively describing particular embodiments only and is not intended to limit the invention.

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

Also, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

Conventional self-healing polyurethane-based resins have a problem that the mechanical properties are lowered as the self-healing performance increases. .

Accordingly, the present inventors have discovered that self-healing performance and mechanical strength can be simultaneously improved by preparing a self-healing polyurethane polymer comprising structural units derived from aliphatic polycarbonate-based polyols, cycloaliphatic polyisocyanates and aliphatic disulfide-based polyols. In particular, it was found that a self-healing polymer having excellent mechanical properties as well as an excellent self-healing effect even at a low temperature such as room temperature can be provided, thereby completing the present invention.

Specifically, the self-healing temperature of the existing polyurethane material having an aliphatic disulfide requires a temperature of 70° C. or higher, but in the present invention, it was discovered for the first time that self-healing is possible even at room temperature by changing the design of the surrounding polymer structure.

The remarkable functional effect is an effect exhibited by including all of an aliphatic polycarbonate-based polyol, an alicyclic polyisocyanate, and an aliphatic disulfide polyol as a monomer, and the monomer is included as a structural unit of the polymer through a polymerization reaction.

In addition, the present invention prepares an isocyanate-terminated polyurethane prepolymer by pre-polymerizing the aliphatic polycarbonate-based polyol and alicyclic polyisocyanate, and then reacts with an aliphatic disulfide-based polyol, for example, an aliphatic disulfide-based diol compound. can be manufactured.

According to one aspect of the present invention, the structural unit of the aliphatic polycarbonate-based polyol includes an alkylene group-carbonate group, and hydroxyl groups (-OH) may be included at both ends or side branches of the molecule. The number of hydroxyl groups included in the molecule of the aliphatic polycarbonate-based polyol may be 2 to 6, preferably 2 to 4, and preferably, each of the hydroxyl groups is included at both ends so that two hydroxyl groups may be included in the molecule. , but is not limited thereto.

As the alkylene group is included in the aliphatic polycarbonate-based polyol, the flexibility of the polymer chain may be improved and the self-healing effect may be increased. The number of carbon atoms of the alkylene group included in the structural unit of the aliphatic polycarbonate-based polyol may be 2 to 10, preferably 2 to 8, and more preferably 4 to 6.

The number average molecular weight of the aliphatic polycarbonate-based polyol may be 300 to 10,000 g/mol, preferably 500 to 5,000 g/mol, more preferably 600 to 4,000 g/mol, very preferably 700 to 3,000 g/mol.

The number average molecular weight of the aliphatic polycarbonate-based polyol is more excellent in flexibility and self-healing effect of the polymer chain within the above range, and the physical properties excellent in tensile strength can be satisfied at the same time.

According to an aspect of the present invention, the alicyclic polyisocyanate may be used without particular limitation as long as it is an alicyclic compound having two or more isocyanate groups, and specifically, for example, isophorone diisocyanate (IPDI), 4, 4'-dicyclohexylmethane diisocyanate (hydrogenated methylene diphenyl diisocyanate, hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated toluene diisocyantate, hydrogenated TDI), bis (2-isocyanate) Natoethyl)-4-diclohexene-1,2-dicarboxylate (Bis(2-isocyanatoethyl)-4-diclohexene-1,2-dicarboxylate), 2,5-norbornene diisocyanate (2,5- any one or two or more selected from norbornene diisocyanate) and 2,6-norbornene diisocyanate (2,6-norbornene diisocyanate) may be used. It is particularly preferable to use isophorone diisocyanate (IPDI) in terms of securing high toughness.

According to an aspect of the present invention, the structural unit of the aliphatic disulfide-based polyol may have 2 to 10 carbon atoms, preferably 3 to 8 carbon atoms, and more preferably 4 to 6 carbon atoms. The weight average molecular weight of the aliphatic disulfide-based polyol may be 50 to 300 g/mol, preferably 80 to 250 g/mol, and more preferably 100 to 200 g/mol.

According to an aspect of the present invention, the aliphatic polycarbonate-based polyol and the aliphatic disulfide-based polyol may be included in the polymer chain. Specifically, the aliphatic polycarbonate-based polyol and the aliphatic disulfide-based polyol may be in a molar ratio of 1: 0.02 to 1.5.

When the composition ratio of the aliphatic polycarbonate-based polyol and the aliphatic disulfide-based polyol in the self-healing polyurethane polymer satisfies the above, it can have excellent mechanical strength and at the same time exhibit an excellent self-healing effect at a low temperature. The present invention is not limited thereto.

According to one aspect of the present invention, the self-healing polyurethane polymer is a self-healing polyurethane in which an isocyanate-terminated polyurethane prepolymer derived from an aliphatic polycarbonate-based polyol and an cycloaliphatic polyisocyanate and an aliphatic disulfide-based polyol are coupled to each other. It may be a polymer.

Specifically, as a one-step reaction for producing a self-healing polyurethane polymer, an isocyanate-terminated polyurethane prepolymer is first prepared by a reaction of an aliphatic polycarbonate polyol having a relatively large molecular weight and an alicyclic polyisocyanate, followed by a second step A high molecular weight polyurethane can be prepared by coupling the prepared prepolymer with an aliphatic disulfide-based polyol through the reaction. The high molecular weight polyurethane prepared as described above is good in that it can maintain self-healing properties and mechanical strength uniformly, and at the same time have very excellent self-healing effect at low temperature.

According to an aspect of the present invention, the unit weight ratio of the aliphatic polycarbonate-based polyol and alicyclic polyisocyanate for preparing the polyurethane prepolymer may be 1: 1.5 to 2.5 equivalent ratio, preferably 1.7 to 2.4 equivalent ratio. and more preferably 1.9 to 2.3 equivalent ratio, but is not limited thereto. The equivalent ratio of the isocyanate group of the polyurethane prepolymer prepared by the reaction of the aliphatic polycarbonate-based polyol and the alicyclic polyisocyanate and the hydroxyl group of the aliphatic disulfide-based polyol may be 1: 0.5 to 1.5 equivalent ratio, preferably 1:0.7 to It may be 1.3 equivalent ratio, preferably 1:0.9 to 1.1 equivalent ratio.

As the self-healing polyurethane polymer is prepared in the equivalence ratio, the degree of crosslinking of the self-healing polyurethane is excellent, and in particular, the content of urethane bonds capable of hydrogen bonding in the self-healing polyurethane polymer is high, It has better mechanical strength and self-healing effect.

The self-healing polyurethane polymer prepared by the above method does not need to add additional materials to impart self-healing properties, and can self-heal without raising the temperature to a higher temperature than necessary, and has high tensile strength under external stress. Therefore, it has an excellent advantage for general use.

The weight average molecular weight of the self-healing polyurethane polymer may be 5,000 to 1,000,000 g/mol, preferably 10,000 to 500,000 g/mol, and more preferably 20,000 to 300,000 g/mol, but is not limited thereto. .

According to an aspect of the present invention, the self-healing polyurethane polymer may have a tensile strength of 30 MPa or more, preferably 40 MPa or more, more preferably 40 MPa to 60 MPa, and a tensile toughness of 40 MJ/m 3 or more. , may preferably have a physical property of 50MJ/m3 to 120MJ/m3, but is not limited thereto.

Although a general polyurethane polymer also has high flexibility and toughness, when an article made of the polymer is subjected to physical damage such as cutting, it cannot recover the physical damage, so that the article has a remarkably low mechanical strength according to the physical damage. In contrast, the self-healing polyurethane polymer according to the present invention forms hydrogen bonds and disulfide groups between various functional groups included in the polymer chain, and at the same time achieves an appropriate balance of flexibility, tensile strength, and toughness to form a self-healing polyurethane polymer. When the made article receives physical damage such as cutting, it can quickly recover the physical damage even at a low temperature, such as room temperature, and has a remarkable effect of rapidly recovering the mechanical strength.

Specifically, the self-healing polyurethane polymer has a tensile strength of 30 MPa or more, preferably 40 Mpa to 60 Mpa, and preferably has an excellent tensile strength of 40 Mpa or more, while at the same time 70% at a temperature condition of 35 ℃, Preferably, it can have a remarkable effect with a self-healing rate of 80% or more.

In addition, the self-healing polyurethane polymer of the present invention may have a tensile strength of 30 MPa or more, preferably a physical property of 40 Mpa to 60 Mpa, and a tensile toughness of 40 to 80 MJ/m 3 and a temperature condition of 35 ° C. After 72 hours, it can have a remarkable effect with a self-healing rate of 70%, preferably 80% or more. In addition, after 72 hours at 25 ℃, it can have a remarkable effect having a self-healing rate of preferably 40% or more.

In addition, the self-healing polyurethane polymer satisfies high mechanical properties, excellent self-healing at room temperature, and high light transmittance at the same time, thereby preventing spoilage of refrigerated or frozen food and medical supplies that may be altered according to temperature. It has excellent applicability as a change detection sensor.

For the application of the temperature change sensor, the self-healing polyurethane polymer is opaque at a low temperature, but increases in transparency at a high temperature above a critical temperature, so it may be desirable to have a characteristic having transparency above a certain level.

As a specific example, when the self-healing polyurethane polymer is formed into a film to form a dense film, the change in light transmittance according to temperature change may be insignificant due to the high transparency of the polymer material. In order to maximize the change in light transmittance, light scattering of incident light is generated in the film, so that it is opaque at a low temperature, but at a high temperature above the critical temperature, light scattering is reduced, and it may be desirable to have a characteristic having a certain level of transparency or more.

In order to implement the transparency change characteristics as described above, the self-healing polyurethane article is not uniformly densified or filmed, and the non-uniform self-healing polyurethane article or porosity containing pores or irregularities on the inside or surface of the article A self-healing polyurethane article can be utilized as a desirable temperature change sensor.

The shape and size of the pores or concavities and convexities is sufficient as long as it can generate light scattering of light incident on the article in the visible light region (380-780 nm), and is not limited to a specific shape or size in a specific range. Illustratively, the average diameter of the pores or irregularities may be 10 nm to 500 μm, preferably 100 nm to 100 μm, and more preferably 150 nm to 10 μm.

In the case of a porous self-healing polyurethane article including pores inside the article, the porosity of the article may be 10 to 95%, specifically 20 to 85%, and more specifically 40 to 80%.

The shape of the article is not limited to a specific shape, and specific examples thereof may be a film, a sheet, a sticker, a web-film, a fiber, or a coating solution.

The present invention provides a self-healing web-film, wherein the self-healing web-film comprises a self-healing polyurethane polymer. Specifically, the self-healing polyurethane polymer may be molded into microfibers, and a plurality of microfibers made of the self-healing polyurethane polymer may be manufactured into a self-healing web-film forming a network structure. In the self-healing web-film, microfibers form a network structure, and thus pores may be included in the network structure, or irregularities may be included on the surface of the web-film.

More specifically, the self-healing web-film is made of a nonwoven fabric in which the self-healing polyurethane polymer is finely fibrous and aggregated, and has opaque properties in a web state. However, at a high temperature above the critical temperature, the fine fibers lose their fibrous shape, and the self-healing polyurethane polymer diffuses into the surrounding pores to fill the empty space of the web, making it homogeneous and dense. It has a behavior that changes to a dense film.

The microfibrillation of the self-healing polyurethane polymer may be prepared by solution spinning or melt spinning.

In the case of the solution spinning, there are various spinning methods such as dry spinning, wet spinning and electrospinning, but in the case of the electrospinning, the diameter of the fiber ranges from nanometer level (~102 nm) to micrometer level (~102 μm). It is preferable because it can be easily adjusted.

Accordingly, the present invention provides a method for producing a self-healing web-film by an electrospinning method. Specifically, the self-healing web-film manufacturing method comprises the steps of: S1) dissolving the self-healing polyurethane polymer in an organic solvent to prepare a self-healing polyurethane solution; S2) forming microfibers by electrospinning the self-healing polyurethane solution; and S3) obtaining a web-film made of the microfibers; includes

Electrospinning may be performed using spinning equipment including a nozzle unit for discharging a polyurethane polymer solution or melt for electrospinning, a high voltage generator, and a current collector. Also, it may be a method in which a microfiber aggregate having a random structure is implemented by the strength of an electric field applied to the discharge.

The concentration of the electrospun polymer solution is not particularly limited as long as electrospinning is possible. In addition, in constituting the polymer solution, the solvent may be used without limitation as long as it is a solvent capable of dissolving the polymer and capable of electrospinning.

According to an aspect of the present invention, the electrospinning may be electrospinning on a coagulation bath.

The coagulation bath may include water, and a current collector may be included in the coagulation bath to be electrospinning on the water surface. As the coagulation bath contains water, the solvent included in the polymer solution is preferably a solvent miscible with water, and water may be a poor solvent for the polymer.

In addition, by including a current collector in the coagulation bath during electrospinning, the self-healing polyurethane polymer microfibers are spun on the water surface of the coagulation bath, and thus the self-healing web in the form of a pure non-woven fabric free from impurities and solvents - The film can be obtained easily.

The self-healing web-film produced by the electrospinning may have a very dense nonwoven structure by combining microfibers having a diameter of a nanometer level (~102 nm) to a micrometer level (~102 μm). Specifically, the average diameter of the microfibers may be 0.01 μm to 200 μm, preferably 0.05 μm to 100 μm, and more preferably 0.1 μm to 50 μm.

In addition, the thickness of the self-healing web-film produced by the electrospinning may be 0.1 μm to 200 μm, preferably 0.5 μm to 150 μm, and more preferably 1 μm to 100 μm.

As the self-healing web-film includes microfibers of the average diameter and forms a network structure, a difference in light transmittance according to temperature change in the visible region can be clearly observed with the naked eye, and the self-healing web - The durability of the film can be increased.

By having such a nonwoven structure, incident light is light-scattered through the network structure formed by the microfibers in the web state, and thus has an opaque property. However, at a high temperature above the critical temperature, the microfiber loses its fibrous shape, and the self-healing polyurethane polymer diffuses into the surrounding pores to fill the empty space of the web, making it homogeneous and dense. It has a behavior that changes to a dense film. According to this behavior, the self-healing web-film may have high light transmittance above the critical temperature or higher.

When the web-film is used as a temperature sensor, it can be trusted that freshness is constantly maintained during storage and distribution if the web-film maintains opacity. On the other hand, if it is a film having transparency, it means that it has been maintained at a temperature of 10°C or higher for a certain period of time during storage and distribution. can provide Accordingly, the temperature sensor including the self-healing web-film according to the present invention may be an irreversible temperature sensor.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the following Examples and Comparative Examples are only examples for explaining the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Evaluation of physical properties]

1) Specimen preparation

Each polymer prepared in Examples and Comparative Examples was dissolved in DMAc solvent at a concentration of 40 wt% to prepare a mixed solution. After the mixed solution was applied on a Teflon sheet, the solvent was removed while the temperature was gradually increased to 100 ° C., and vacuum dried at 110 ° C. to prepare a film having a thickness of 1 mm, and the physical properties were measured.

2) Measurement of tensile strength (MPa) and tensile toughness (MJ/㎥)

Tensile strength and tensile toughness were measured using the Intstron 5943 (UK) equipment for the prepared film in accordance with ASTM D638-03 standards and methods.

Tensile strength was measured at 25° C. with a load cell of 1 KN and a crosshead speed of 100 mm/min, and the average value measured 5 times for each sample was taken.

The tensile toughness was converted into MJ/m ³ as the integral value of the strain-stress curve up to the cut strain.

3) Self-healing rate (%) measurement

In order to measure the self-healing rate, a self-healing polyurethane polymer specimen (thickness 1 mm) of the standard conforming to ASTM D638-03 was prepared and then cut in the middle. The cut section of the specimen was re-bonded while maintaining it at a temperature of 35° C. for 48 hours. The tensile toughness of the rejoined specimen was measured, and the recovery rate compared to before cutting was calculated using the following relational formula (1).

[Relational Expression 1]

T ₁ /T _o * 100

(The T _o is the self-healing polyurethane polymer before cutting toughness (MJ/m3), and T ₁ is the self-healing polyurethane polymer after cutting and re-bonding at a temperature of 35° C. for 48 hours (MJ/m3). m ³ ).

4) Absorbance measurement

Absorbance was measured by measuring the absorbance of the film with a UV-2600 UV/vis spectrometer by preparing a film with a thickness of 0.3 mm when preparing a film by the above specimen preparation method, and the absorbance at 420 nm, which is a yellow light region, was quantified.

[Example 1]

After adding 14.5 g of poly(hexamethylene carbonate) diol, HPCD, Mn 1,000 g/mol, 14.5 mmol) to a 0.5 L three-necked flask equipped with a mechanical stirrer and thermometer, vacuum drying at 100 ° C. was removed.

A mixed solution was prepared by dissolving 6.77 g of isophorone diisocyanate (IPDI, 30.45 mmol) and 50 mg of dibutyltin dilaurate (DBTDL) in 5 ml of dimethylacetamide (DMAc).

The mixed solution was slowly added dropwise to the polyhexamethylene carbonate diol and stirred for 2 hours to prepare a polyurethane prepolymer having a weight average molecular weight of 5,000 g/mol.

Thereafter, after lowering the temperature of the polyurethane prepolymer to 25°C, a solution of 10 ml of dimethylacetamide in which 2.24 g of 2-hydroxyethyl disulfide (14.5 mmol) was dissolved was added dropwise and stirred at 40°C for 1.5 hours. Thus, a self-healing polyurethane polymer was prepared.

Using the self-healing polyurethane polymer prepared above, a film with a thickness of 1 mm was prepared by the method for preparing the specimen, and the tensile strength and tensile toughness were measured and described in Table 1. In addition, in order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen according to ASTM D638-03, cut in the middle, and measured by rejoining it, and the absorbance was measured in Table 1 included.

[Comparative Example 1]

In Example 1, all processes were performed in the same manner as in Example 1 except that 3.63 g of bis(4-hydroxyphenyl)disulfide (Bis(4-hydroxyphenyl)disulfide, 14.5 mmol) was added instead of 2-Hydroxyethyl disulfide.

[Comparative Example 2]

In Example 1, all processes were performed in the same manner as in Example 1 except that 1.71 g of 1,6-hexanediol (1,6-hexanediol, 14.5 mmol) was added instead of 2-Hydroxyethyl disulfide.

[Comparative Example 3]

In Example 1, all processes were performed in the same manner as in Example 1, except that 14.5 g of polytetramethylene ether glycol (Polytetramethylene ether glycol, Mn 1,000 g/mol, 14.5 mmol) was added instead of polyhexamethylene carbonate diol.

[Comparative Example 4]

In Example 1, all processes were the same as in Example 1 except that bis(4-isocyanatophenyl)methane (4,4-Diphenylmethane diisocyanate, MDI, 30.45 mmol, 7.62 g) was added instead of isophorone diisocyanate. proceeded.

	Tensile strength (MPa)	Tensile toughness (MJ/m 3 )	Self-healing rate (%, 25 degrees/72 hours)	Self-healing rate (%, 35 degrees / 6 hours)	absorbance (420 nm)
Example 1	45	65	49	88	0.004
Comparative Example 1	43	75	40	49	0.15
Comparative Example 2	68	117	32	36	0.004
Comparative Example 3	3	12	100	100	0.02
Comparative Example 4	58	120	0	0	0.11

As shown in Table 1, in the case of a polyurethane including a structural unit derived from a polycarbonate-based polyol, an alicyclic polyisocyanate and an aliphatic polyol containing a disulfide functional group as in Example 1, the tensile strength of the specimen was 30 MPa or more, tensile toughness of 40 MJ/m3 or more was achieved, and after cutting and rejoining the specimen, after 72 hours at 25°C, room temperature self-healing with a tensile toughness recovery rate of 40% or more It functions as a polyurethane material. In addition, after 6 hours at 35°C after cutting and rejoining the specimen, it functioned as a room temperature self-healing polyurethane material with a tensile toughness recovery rate of 70% or more. In addition, it was confirmed that the self-healing polyurethane polymer film at room temperature with a thickness of 0.3 mm had an absorbance of 0.1 or less at 420 nm and had excellent transparency.

On the other hand, in the case of an aromatic polyol containing a disulfide functional group rather than an aliphatic polyol containing a disulfide functional group (Comparative Example 1), surprisingly, it showed a poorer room temperature self-healing rate and had poor transparency. This is a result that deviates from the expectation that the self-healing temperature of the aliphatic disulfide polyol is 80 degrees or higher in the existing literature (A Novel Self Healing Polyurethane Based on Disulfide Bonds, https://doi.org/10.1002/macp.201600011). , it is considered to be a remarkable effect as a possible result because the crystalline hard domain structure of the polyurethane is resolved into an amorphous form in the present invention.

On the other hand, in the case of an aliphatic polyol consisting only of carbon/hydrogen, not an aliphatic polyol containing a disulfide functional group (Comparative Example 2), the self-healing rate at room temperature was lower than expected because only a hydrogen bond acts as a self-healing functional group.

On the other hand, in the case of the ether-based polyol rather than the polycarbonate-based polyol (Comparative Example 3), the interaction with the urethane group (hard segment) chain was weak, and thus showed low physical properties.

On the other hand, in the case of an aromatic polyisocyanate rather than an alicyclic polyisocyanate (Comparative Example 4), high mechanical properties were achieved by forming a crystalline hard domain, but the disulfide self-healing functional group was trapped inside, so room temperature self-healing was hardly expressed. didn't

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

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

Claims (9)

1. A self-healing polyurethane polymer comprising a structural unit derived from an aliphatic polycarbonate-based polyol, an alicyclic polyisocyanate, and an aliphatic disulfide-based polyol.
2. The method of claim 1,

   The self-healing polyurethane polymer is a self-healing polyurethane polymer in which a polyurethane prepolymer derived from an aliphatic polycarbonate-based polyol and an alicyclic polyisocyanate and an aliphatic disulfide-based polyol are coupled by coupling.
3. The method of claim 1,

   The aliphatic polycarbonate-based polyol is a self-healing polyurethane polymer having a number average molecular weight of 300 to 10,000 g/mol.
4. The method of claim 1,

   A self-healing polyurethane polymer having 2 to 10 carbon atoms in the alkylene group of the structural unit of the aliphatic polycarbonate-based polyol.
5. The method of claim 1,

   A self-healing polyurethane polymer having 2 to 10 carbon atoms in the structural unit of the aliphatic disulfide-based polyol.
6. The method of claim 1,

   The aliphatic polycarbonate-based polyol and the aliphatic disulfide-based polyol are 1: 0.02 to 1.5 weight ratio of self-healing polyurethane polymer.
7. 3. The method of claim 2,

   The aliphatic polycarbonate-based polyol and the alicyclic polyisocyanate are a polyurethane prepolymer having an equivalent ratio of 1: 1.5 to 2.5, and the equivalent ratio of the isocyanate group of the polyurethane prepolymer and the hydroxyl group of the aliphatic disulfide-based polyol is 1: 0.5 to 1.5 Value-based polyurethane polymers.
8. The method of claim 1,

   The self-healing polyurethane polymer is a self-healing polyurethane polymer satisfying the following relation 1, wherein the self-healing effect is 70% or more when left at 35 ° C. for 72 hours.

   [Relational Expression 1]

   T ₁ /T _o * 100

   (The T _o is the self-healing polyurethane polymer before cutting toughness (MJ/m3), and T ₁ is the self-healing polyurethane polymer after cutting and re-bonding at a temperature of 35° C. for 48 hours (MJ/m3). m3) The specimen was prepared with a self-healing polyurethane polymer specimen (thickness of 1 mm) conforming to ASTM D638-03, cut in the middle, and rejoined while maintaining the cut section at a temperature of 35 ° C for 72 hours. )
9. A porous self-healing polyurethane article comprising the self-healing polyurethane polymer of any one of claims 1 to 8.