KR102402169B1 - High-strength self-healing polyurethane polymer and web-film for temperature sensors comprising the same - Google Patents

Abstract

The present invention relates to a self-healing polyurethane polymer having high tensile strength and a high self-healing effect at the same time and a method for preparing the same. Specifically, by providing a self-healing polyurethane polymer comprising structural units derived from polycarbonate-based polyols, cycloaliphatic polyisocyanates and aliphatic polyols, it has excellent self-healing effect and high mechanical strength even at room temperature, and at the same time has excellent transparency By having it, it has excellent usefulness as a temperature sensor and a display film.

Description

High-strength self-healing polyurethane polymer and web-film for temperature sensor comprising the same

The present invention relates to a high-strength self-healing polyurethane polymer having high tensile strength and high self-healing effect, and a web-film for a temperature sensor comprising the same.

A self-healing material that can autonomously and repeatedly recover from physical damage through dynamic physical and chemical bonding can be applied to various material fields such as automobiles, electronics, robotics, and medical devices. .

Most of these self-healing materials have lower tensile and flexural strength than commercial rubber due to their material characteristics. On the other hand, when the mechanical strength of the self-healing material is increased, there is a problem that the self-healing effect is rapidly reduced.

That is, the high chain rigidity, entanglement, and crystallinity of the polymer for mechanical strengthening are variables contrary to the high diffusion and exchange of dynamic bonds for self-healing, and it is difficult to simultaneously improve the mechanical strength and the self-healing effect.

Accordingly, there is a demand for the development of a self-healing material having excellent self-healing effect and at the same time having mechanical properties suitable for commercialization in actual industry.

Republic of Korea Patent Publication No. 10-2015-0097902 (2015.08.27.)

An object of the present invention is to provide a high-strength self-healing polyurethane polymer having high tensile strength and excellent self-healing.

In addition, an object of the present invention is to provide a self-healing web-film having an onset point at a specific temperature, and in which the microfibers are irreversibly self-fused to each other at the onset point, thereby increasing transparency.

In addition, an object of the present invention is to provide a self-healing polyurethane polymer having excellent transparency and suitable for use in functional display films and the like.

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

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

According to an aspect of the present invention, the polycarbonate-based polyol may include an aliphatic polycarbonate-based polyol.

According to an aspect of the present invention, the polycarbonate-based polyol may have a number average molecular weight of 500 to 5000 g/mol.

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

According to an aspect of the present invention, the structural unit of the aliphatic polyol may have 4 to 6 carbon atoms.

According to an aspect of the present invention, the polycarbonate-based polyol and the aliphatic polyol may be in a weight ratio of 1: 0.02 to 0.5.

According to one aspect of the present invention, the polycarbonate-based polyol and the alicyclic polyisocyanate are a polyurethane prepolymer in 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 polyol is 1: 0.5 to It may be 1.5.

According to one aspect of the present invention, the self-healing polyurethane polymer may have a tensile strength of 25 MPa or more, and satisfy the following Relational Equation 1.

[Relational Expression 1]

50 ≤ T ₁ /T _o * 100

(In the above relation 1, T _o is the toughness (MJ/m ³ ) measured at a temperature condition of 35 ° C before cutting the film made of the self-healing polyurethane polymer, and T ₁ is the film made of the self-healing polyurethane polymer Toughness (MJ/m ³ ) measured after cutting and re-bonding the cut section for 48 hours at a temperature of 35 ° C. The film made of the self-healing polyurethane polymer has a dumbbell shape conforming to ISO 37-4. and the thickness is 1 mm.)

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

Another aspect of the present invention provides a method for producing a self-healing web-film,

S1) preparing a self-healing polyurethane solution by dissolving the self-healing polyurethane polymer of the first aspect in an organic solvent;

S2) forming microfibers by electrospinning the self-healing polyurethane solution; and

S3) the web made of the microfibers - obtaining a film; includes.

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

According to an aspect of the present invention, the coagulation bath may include water, and a current collector may be included in the coagulation bath to be electrospinning on the water surface.

According to an aspect of the present invention, it may include a plurality of microfibers made of the self-healing polyurethane polymer, and the plurality of microfibers may provide a self-healing web-film forming a network structure.

According to an aspect of the present invention, the self-healing web-film may have a light transmittance of 25% or less at a wavelength of 380 to 780 nm.

According to an aspect of the present invention, the self-healing web-film has an onset point at a temperature of 10° C. or higher, and the microfibers irreversibly self-fuse each other at the onset point, thereby increasing transparency.

According to one aspect of the present invention, the microfiber may be prepared by solution spinning or melt spinning.

According to an aspect of the present invention, the average diameter of the fine fibers constituting the self-healing web-film may be 0.01 μm to 200 μm.

According to one aspect of the present invention, it is possible to provide a temperature sensor comprising the self-healing web-film.

The present invention can provide a self-healing polyurethane polymer having both excellent mechanical strength and a self-healing effect that cannot be achieved by conventional polyurethane polymers.

In addition, the present invention provides a web-film in the form of a nonwoven fabric in which the self-healing polyurethane polymer is microfibrillated, wherein the web-film has an onset point at a specific temperature, and the microfibers are irreversibly connected to each other at the onset point. It is possible to provide a self-healing web-film having increased transparency by self-fusing.

In addition, since the present invention does not use a compound such as a sulfur compound, it has excellent transparency and at the same time has self-healing properties and has recovery ability against various physical damages such as scratches, so it has properties very suitable for use in functional display films and the like.

1 is a graph showing a tensile stress graph of Example 1 and a change in tensile toughness before and after self-healing.
2 is a view showing a photograph and a WAXS pattern showing the degree of crystallization due to external stress in Example 1.
3 is a self-healing web of Example 5 - a schematic diagram of electrospinning to prepare a film.
4 is a view showing the change in transparency of the self-healing web-film of Example 5 and Comparative Example 6 after being exposed at 25° C. for 48 hours.

Hereinafter, the present invention will be described in more detail through embodiments or examples including the accompanying drawings. 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.

In addition, the 'onset point' described in the specification means a 'critical temperature' at which the self-healing polyurethane can start self-healing, and self-healing does not occur below the onset point, and self-healing is triggered only above the onset point. ) can be Accordingly, 'onset point' and 'critical temperature' are used herein as terms that are interchangeable with each other.

Conventional self-healing polyurethane-based resins have a problem in that 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 polycarbonate-based polyols, cycloaliphatic polyisocyanates and aliphatic polyols, and the present invention was completed.

The self-healing polyurethane polymer is uniquely capable of self-healing at room temperature under the influence of disordered hydrogen bonding in an amorphous state and low phase separation state in the absence of external stress, but is meta-stable under external stress It has a remarkable effect of having high mechanical strength under the influence of ordered hydrogen bonds and crystals by changing to a single crystal state.

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

According to an aspect of the present invention, the polycarbonate-based polyol may include an aliphatic polycarbonate-based polyol.

The aliphatic polycarbonate-based polyol has a structural unit including 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. , is not limited to a specific numerical range.

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 4 to 10, preferably 4 to 8, and more preferably 4 to 6.

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

In the range of the number average molecular weight of the polycarbonate-based polyol of 500 to 5,000 g/mol, the flexibility and self-healing effect of the polymer chain are more excellent, and the physical properties excellent in tensile strength can be satisfied at the same time. More preferably, in the range of 600 to 4,000 g/mol, more preferably 700 to 3,000 g/mol, a more excellent effect can be expressed.

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 polyol may have 2 to 10 carbon atoms, preferably 3 to 8 carbon atoms, and more preferably 4 to 6 carbon atoms.

The aliphatic polyol is a chain extender for coupling the polyurethane prepolymer, and has an advantage in increasing the molecular weight of the self-healing polyurethane polymer during the coupling reaction.

The weight average molecular weight of the aliphatic polyol may be 50 to 300 g/mol, preferably 60 to 200 g/mol, and more preferably 70 to 150 g/mol.

According to an aspect of the present invention, the polycarbonate-based polyol may be included in the polymer chain in an amount greater than that of the aliphatic polyol. Specifically, the polycarbonate-based polyol and the aliphatic polyol may be in a weight ratio of 1: 0.02 to 0.5, preferably 1:0.04 to 0.4, and more preferably 1:0.06 to 0.3 by weight.

Since the weight of the polycarbonate-based polyol is higher than the weight of the aliphatic polyol in the self-healing polyurethane polymer, the self-healing polyurethane polymer can have excellent mechanical strength, and at the same time, a self-healing effect can also be exhibited. do.

According to an aspect of the present invention, the self-healing polyurethane polymer may be a self-healing polyurethane polymer in which a polyurethane prepolymer derived from a polycarbonate-based polyol and an cycloaliphatic polyisocyanate and an aliphatic polyol are coupled by coupling.

Specifically, as a one-step reaction for producing a self-healing polyurethane polymer, a polyurethane prepolymer is first prepared by a reaction of a polycarbonate polyol having a relatively large molecular weight and an alicyclic polyisocyanate, and then a second step reaction By coupling the prepolymer and the aliphatic polyol, a high molecular weight polyurethane can be prepared, which is preferable. In addition, as a high molecular weight polyurethane is prepared, it may be preferable in terms of being able to uniformly maintain the self-healing properties and mechanical strength of the polyurethane.

In another aspect of the present invention, the self-healing polyurethane polymer may be a self-healing polyurethane polymer in which a polyurethane prepolymer derived from an aliphatic polyol and an cycloaliphatic polyisocyanate and a polycarbonate polyol are coupled by coupling. .

According to an aspect of the present invention, the polycarbonate-based polyol and the alicyclic polyisocyanate may be in an equivalent ratio of 1: 1.5 to 2.5, preferably in an equivalent ratio of 1.7 to 2.4, and more preferably in an equivalent ratio of 1.9 to 2.3. . The equivalent ratio of the isocyanate group of the polyurethane prepolymer prepared by the reaction of the polycarbonate-based polyol and the alicyclic polyisocyanate and the hydroxyl group of the aliphatic polyol may be 1: 0.5 to 1.5 equivalent ratio, preferably 1: 0.7 to 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 25 MPa or more, preferably 30 MPa to 50 MPa, and simultaneously satisfying the tensile strength of the above range and the following relational expression 1 can

[Relational Expression 1]

50 ≤ T ₁ /T _o * 100

(In the above relation 1, T _o is the toughness (MJ/m ³ ) measured at a temperature condition of 35 ° C before cutting the film made of the self-healing polyurethane polymer, and T ₁ is the film made of the self-healing polyurethane polymer Toughness (MJ/m ³ ) measured after cutting and re-bonding the cut section for 48 hours at a temperature of 35 ° C. The film made of the self-healing polyurethane polymer has a dumbbell shape conforming to ISO 37-4. and the thickness is 1 mm.)

The toughness of the self-healing polyurethane polymer may be measured by a standard and method conforming to ASTM D638-03.

Specifically, T ₁ /T _o * 100 in Relation 1 may have a value of 50 to 90, more specifically, a value of 50 to 70.

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. On the other hand, the self-healing polyurethane polymer according to the present invention forms hydrogen bonds between various functional groups included in the polymer chain, and at the same time achieves an appropriate balance of flexibility, tensile strength and toughness, so that an article made of a self-healing polyurethane polymer In case of physical damage such as this cut, the physical damage can be quickly restored, and the mechanical strength also has a remarkable effect that can be quickly restored.

Specifically, the self-healing polyurethane polymer can exhibit a remarkable effect of having a self-healing rate of 50% or more as defined by the above-mentioned formula under a temperature condition of 35°C while having a tensile strength of 25 MPa or more.

In addition, the self-healing polymers developed so far essentially contain a specific functional group such as a thiol group or a disulfide bond in the polymer chain for realization of self-healing properties, and the polymer chain through a mechanism such as oxidation-reduction reaction of the specific functional group Self-healing properties have been realized through the method of recombination of chemical cleavage of However, the self-healing polyurethane polymer according to the present invention does not include a specific functional group, and does not take a way to recombine chemical cleavage of the polymer chain. Rather, it should be noted that the self-healing properties were realized by guiding bonding and dissociation to occur reversibly using hydrogen bonding, which is a physical bond between various functional groups, and at the same time balancing flexibility, tensile strength, and toughness appropriately. .

In other words, since a specific functional group such as a thiol group or a disulfide bond is not included in the polymer chain, no coloring phenomenon occurs, and thus the light transmittance is relatively excellent. have a gender In particular, as the self-healing polyurethane polymer according to the present invention has self-healing properties above the onset point, it has recovery ability against various physical damages such as scratches when the operating temperature is above the onset point, making it very suitable for use in functional display films, etc. have suitable characteristics.

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 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 the 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, so it may be desirable to have a characteristic having a certain level or more of transparency.

In order to implement the transparency change characteristics as described above, the self-healing polyurethane article is not densified, and the non-uniform self-healing polyurethane article or porous self-healing polyurethane containing pores or irregularities on the inside or surface of the article The 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 within 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%, 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 in which a network structure is formed. 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 non-woven 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 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.

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 is at the nanometer level (~102 nm) to ^{the micrometer level (~10 2 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 electrospinning polymer solution is not particularly limited as long as the 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 plate 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 (~ 10 2 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, the 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, in the web state, incident light is light-scattered through the network structure formed by the microfibers, 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.

The self-healing web-film may have a light transmittance of 25% or less at a wavelength of 380 to 780 nm at a temperature below the onset point, preferably 15% or less, and more preferably 10% or less can be

The self-healing web-film may have an onset point at a temperature of 10° C. or higher. At a temperature above the onset point, the microfibers irreversibly self-fused to each other, thereby increasing transparency. This means that the self-healing web-film maintains the nonwoven form at a temperature below the onset point, but is converted from the nonwoven form to the film form at a temperature of 10° C. or more, and the transparency increases.

Specifically, the onset point may be 15°C or higher, specifically 20°C or higher, and may be 30°C or lower without limitation, but it is not limited to a specific numerical range because it corresponds to a design variable that may vary according to application examples.

For example, when storing and distributing temperature-sensitive meat and fish, there is a risk of loss of freshness and deterioration due to temperature rise. Accordingly, when a self-healing web-film having an onset point of 10°C is used as a temperature sensor, it can be trusted that the 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 merely 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]

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.

1) 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.

2) 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 (2).

[Relational Expression 2]

T ₁ /T _o * 100

(In Relation 2, T _o is the pre-cut toughness of the self-healing polyurethane polymer (MJ/m ³ ), and T ₁ is the self-healing polyurethane polymer cut and reattached at a temperature of 35 ° C. for 48 hours. After toughness (MJ/m ³ ).)

3) Measurement of transmittance

Using a UV-VIS spectrophotometer (UV-2600, Shimadzu Co.), Examples 5 to 6, the web-films prepared in Comparative Examples 5 to 6, and the film prepared in Comparative Example 7 were each prepared at 25 ° C. for 48 hours. The light transmittance (T%) of the exposed microfiber-based web-film was measured under the same green light (λ=560 nm) light source (slit size=2 mm).

[Example 1]

14.5 g of polyhexamethylene carbonate diol (HPCD, Mn 1,000 g/mol, 14.5 mmol) was added to a 0.5 L three-necked flask equipped with a mechanical stirrer and a thermometer, and then the moisture was removed by vacuum drying at 100 ° C.

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 15,000 g/mol.

Thereafter, after lowering the temperature of the polyurethane prepolymer to 25° C., a 10 ml solution of dimethylacetamide in which 1.71 g of 1,6-hexanediol (1,6-hexanediol, 14.5 mmol) was dissolved was added dropwise, followed by 1.5 hours at 40° C. A self-healing polyurethane polymer was prepared by stirring.

The prepared self-healing polyurethane polymer was prepared as a film with a thickness of 1 mm, and its tensile strength was measured and described in Table 1.

In order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen having a standard conforming to ASTM D638-03, and then cut in the middle and rejoined.

Table 1 shows the self-healing rates of the samples.

The toughness before cutting was 52 MJ/m ³ , and the toughness after cutting the self-healing polyurethane polymer film and rejoining it for 48 hours at 35° C. was 28 MJ/m ³ and the self-healing rate was 54%.

[Example 2]

In Example 1, all processes were performed in the same manner as in Example 1 except that 1,4-butanediol (1,4-butanediol, 14.5 mmol, 1.31 g) was added instead of 1,6-hexanediol.

The prepared self-healing polyurethane polymer was prepared as a film with a thickness of 1 mm, and its tensile strength was measured and described in Table 1.

In order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen having a standard conforming to ASTM D638-03, and then cut in the middle and rejoined.

Table 1 shows the self-healing rates of the samples.

The prepared self-healing polyurethane polymer had a toughness of 48 MJ/m ³ before cutting, and the toughness after cutting the self-healing polyurethane polymer and rejoining it for 48 hours at 35 ° C was 25 MJ/m ³ . The cure rate was 52%.

[Example 3]

In Example 1, all the steps were performed with Example 1 except that polyhexamethylene carbonate diol (58.0 g) having a number average molecular weight of 4000 g/mol was added instead of polyhexamethylene carbonate diol having a number average molecular weight of 1000 g/mol. It proceeded in the same way.

The prepared self-healing polyurethane polymer was prepared as a film with a thickness of 1 mm, and its tensile strength was measured and described in Table 1.

In order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen having a standard conforming to ASTM D638-03, and then cut in the middle and rejoined.

Table 1 shows the self-healing rates of the samples.

The prepared self-healing polyurethane polymer had a toughness of 40 MJ/m ³ before cutting, and the toughness after cutting the self-healing polyurethane polymer and rejoining it for 48 hours at 35 ° C was 20 MJ/m ³ . The cure rate was 50%.

[Example 4]

In Example 1, all the steps were performed with Example 1 except that polyhexamethylene carbonate diol (29.0 g) having a number average molecular weight of 2000 g/mol was added instead of polyhexamethylene carbonate diol having a number average molecular weight of 1000 g/mol. It proceeded in the same way.

The prepared self-healing polyurethane polymer was prepared as a film with a thickness of 1 mm, and its tensile strength was measured and described in Table 1.

In order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen having a standard conforming to ASTM D638-03, and then cut in the middle and rejoined.

Table 1 shows the self-healing rates of the samples.

The prepared self-healing polyurethane polymer had a toughness of 38 MJ/m ³ before cutting, and the toughness after cutting the self-healing polyurethane polymer and re-bonding at a temperature of 35 ° C for 48 hours was 20 MJ/m ³ . The cure rate was 52%.

[Comparative Example 1]

In Example 1, all the processes were the same as in Example 1, except that polytetramethylene ether glycol (PTMEG, 14.5 mmol, 14.5 g, number average molecular weight 1,000 g/mol, manufactured by Korea PTG) was added instead of polyhexamethylene carbonate diol. It proceeded in the same way.

The prepared self-healing polyurethane polymer was prepared as a film with a thickness of 1 mm, and its tensile strength was measured and described in Table 1.

In order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen having a standard conforming to ASTM D638-03, and then the center was cut and rejoined.

Table 1 shows the self-healing rates of the samples. The prepared self-healing polyurethane polymer had a toughness of 12 MJ/m ³ before cutting, and the toughness after cutting the self-healing polyurethane polymer and re-bonding at a temperature of 35 ° C for 48 hours was 12 MJ/m ³ . The cure rate was 100%.

[Comparative Example 2]

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.

The prepared self-healing polyurethane polymer was prepared as a film with a thickness of 1 mm, and its tensile strength was measured and described in Table 1.

In order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen having a standard conforming to ASTM D638-03, and then the center was cut and rejoined.

Table 1 shows the self-healing rates of the samples.

The prepared self-healing polyurethane polymer had a toughness of 60 MJ/m ³ before cutting, and the toughness after cutting the self-healing polyurethane polymer and re-bonding at a temperature of 35 ° C for 48 hours was 0 MJ/m ³ . The cure rate was 0%.

[Comparative Example 3]

In Example 1, all the steps were performed with Example 1 except that polyhexamethylene carbonate diol (4.35 g) having a number average molecular weight of 300 g/mol was added instead of polyhexamethylene carbonate diol having a number average molecular weight of 1000 g/mol. It proceeded in the same way. Tensile strength and self-healing rate of the prepared self-healing polyurethane polymer were measured and described in Table 1. The prepared self-healing polyurethane polymer had a toughness of 32 MJ/m ³ before cutting, and the toughness after cutting the self-healing polyurethane polymer and rejoining it for 48 hours at 35 ° C was 8 MJ/m ³ . The cure rate was 25%.

[Comparative Example 4]

In Example 1, all the processes were the same as in Example 1 except that polyhexamethylene carbonate diol (101.5 g) having a number average molecular weight of 7000 g/mol was added instead of polyhexamethylene carbonate diol having a number average molecular weight of 1000 g/mol. It proceeded in the same way.

The prepared self-healing polyurethane polymer was prepared as a film with a thickness of 1 mm, and its tensile strength was measured and described in Table 1.

In order to measure the self-healing rate of the sample, the self-healing polyurethane polymer was prepared as a specimen having a standard conforming to ASTM D638-03, and then the center was cut and rejoined.

Table 1 shows the self-healing rates of the samples.

The prepared self-healing polyurethane polymer had a toughness of 20 MJ/m ³ before cutting, and the toughness after cutting the self-healing polyurethane polymer and rejoining it for 48 hours at 35 ° C was 8 MJ/m ³ . The cure rate was 40%.

Tensile strength (MPa) Self-healing rate (%) Example 1 40 54 Example 2 32 52 Example 3 26 50 Example 4 28 52 Comparative Example 1 4 100 Comparative Example 2 48 0 Comparative Example 3 27 25 Comparative Example 4 17 40

As shown in Table 1, polyurethane polymerized from a composition containing a carbonate-type polyol and an alicyclic polyisocyanate as in Examples 1 and 2 showed high tensile strength and self-healing rate. On the other hand, as in Comparative Example 1, the self-healing polyurethane prepared using a polyether-type polyol rather than a carbonate-based polyol had a high self-healing rate, but was found to have a very low tensile strength.

On the other hand, it was found that when an aromatic polyisocyanate was used as the polyisocyanate, it had no self-healing ability at all due to the rigidity of the polymer chain.

The remarkable self-healing power and mechanical properties of Examples 1 to 4 are in a reversible crystal change caused by an external stress, which, as shown in FIG. -ray scattering (WAXS)) pattern was confirmed.

[Example 5]

The self-healing polyurethane polymer obtained in Example 1 was dissolved in a complex solvent composed of dimethylacetamide and tetrahydrofuran (THF) in a 3:7 volume ratio at a concentration of 20 wt% to prepare a self-healing polyurethane solution.

After injecting the prepared self-healing polyurethane solution into the cylinder, a voltage of 6.5 kV was applied to the polymer solution using a High Voltage Power Supply and spun for 2 minutes and 30 seconds. At this time, the spinning nozzle was 24 gauge (diameter 0.31 mm), the solution discharge rate was 1 ml/h, and the distance from the nozzle to the metal collector was 15 cm. As shown in FIG. 3 , a coagulation bath filled with distilled or tap water was placed under the spinning nozzle to collect the microfiber-based web-film from which impurities such as residual solvent and dust were removed.

The microfiber-based web-film collected on the upper part of the coagulation bath was taken as a square frame with outer and inner side lengths of 5 and 3 cm, respectively, and dried at room temperature (20 ° C) for about 30 minutes, as listed in Table 2 below. , a web-film with a thickness of 6.4 ㎛ was prepared, and it was attached to the upper and lower PET films (SKC) for microfiber-based web-film protection, and the light transmittance (UV-2600, Shimadzu Co.) was used to measure the light transmittance ( %) and the results are listed in Table 2.

[Example 6]

A web-film was prepared in the same manner as in Example 5, except that the self-healing polyurethane polymer prepared in Example 2 was used instead of the self-healing polyurethane polymer prepared in Example 1.

In addition, the light transmittance (%) of the prepared web-film was measured in the same manner as described in Example 5, and the results are listed in Table 2.

[Comparative Example 5]

A web-film was prepared in the same manner as in Example 5, except that the self-healing polyurethane polymer prepared in Comparative Example 1 was used instead of the self-healing polyurethane polymer prepared in Example 1.

In addition, the light transmittance (%) of the prepared web-film was measured in the same manner as described in Example 5, and the results are listed in Table 2.

[Comparative Example 6]

A web-film was prepared in the same manner as in Example 5, except that the self-healing polyurethane polymer prepared in Comparative Example 2 was used instead of the self-healing polyurethane polymer prepared in Example 1.

In addition, the light transmittance (%) of the prepared web-film was measured in the same manner as described in Example 5, and the results are listed in Table 2.

[Comparative Example 7]

A mixed solution was prepared by dissolving the self-healing polyurethane polymer prepared in Example 1 in a DMAc solvent at a concentration of 40 wt%.

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 with a thickness of 10 µm, and a PET film (SKC) on the prepared film. was attached to the top and bottom, and the light transmittance (%) was measured with a UV-VIS spectrophotometer (UV-2600, Shimadzu Co.), and the results are listed in Table 2.

temperature Senser Permeability (%) 5 ℃ 25℃ (48 hours exposure) Example 5 0.5 21.0 Example 6 0.5 18.7 Comparative Example 5 - - Comparative Example 6 0.2 0.5 Comparative Example 7 85.2 85.1

As shown in Table 2, in the web-film prepared from the microfibers according to Example 5, the microfibers are fused by the self-healing phenomenon under the conditions of a specific temperature range to change into a uniform film, thereby increasing the light transmittance. it was confirmed

As described above, the present invention has been described with reference to specific matters 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 to be described later, 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 (19)

A porous self-healing polyurethane article comprising a polycarbonate-based polyol, a self-healing polyurethane polymer comprising a structural unit derived from an alicyclic compound having two or more isocyanate groups and an aliphatic polyol. The method of claim 1,
The self-healing polyurethane polymer is a porous self-healing polyurethane article in which a polyurethane prepolymer derived from a polycarbonate-based polyol and an alicyclic compound having two or more isocyanate groups and an aliphatic polyol are coupled by coupling. The method of claim 1,
The polycarbonate-based polyol is a porous self-healing polyurethane article that is an aliphatic polycarbonate-based polyol. The method of claim 1,
The polycarbonate-based polyol is an aliphatic polycarbonate-based polyol having a number average molecular weight of 500 to 5000 g/mol. A porous self-healing polyurethane article. The method of claim 1,
A porous self-healing polyurethane article having 4 to 10 carbon atoms in the alkylene group of the structural unit of the polycarbonate-based polyol. The method of claim 1,
A porous self-healing polyurethane article having 4 to 6 carbon atoms in the structural unit of the aliphatic polyol. The method of claim 1,
The polycarbonate-based polyol and the aliphatic polyol are 1: 0.02 to 0.5 weight ratio of a porous self-healing polyurethane article. 3. The method of claim 2,
The polycarbonate-based polyol and the alicyclic compound having two or more isocyanate groups is a polyurethane prepolymer in 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 polyol is 1: 0.5 to 1.5 Phosphorus porous self-healing polyurethane article. The method of claim 1,
The self-healing polyurethane polymer has a tensile strength of 25 MPa or more, and a porous self-healing polyurethane article satisfying the following relation (1).
[Relational Expression 1]
50 ≤ T ₁ /T _o * 100
(In the above relation 1, T _o is the toughness (MJ/m ³ ) measured at a temperature condition of 35 ° C before cutting the film made of the self-healing polyurethane polymer, and T ₁ is the film made of the self-healing polyurethane polymer Toughness (MJ/m ³ ) measured after cutting and re-bonding the cut section for 48 hours at a temperature of 35 ° C. The film made of the self-healing polyurethane polymer has a dumbbell shape conforming to ISO 37-4. and the thickness is 1 mm.) delete S1) preparing a self-healing polyurethane solution by dissolving the self-healing polyurethane polymer of any one of claims 1 to 9 in an organic solvent;
S2) forming microfibers by electrospinning the self-healing polyurethane solution; and
S3) obtaining a web-film made of the microfibers;
A self-healing web containing a method for producing a film. 12. The method of claim 11,
The electrospinning is a method of producing a self-healing web-film by electrospinning on a coagulation bath. 13. The method of claim 12,
The coagulation bath includes water, and a current collector plate is included in the coagulation bath to electrospinning on the water surface - a self-healing web method for producing a film. The porous self-healing polyurethane article of any one of claims 1 to 9 is that a plurality of microfibers are formed in a network structure, a self-healing web-film. 15. The method of claim 14,
The self-healing web-film is an opaque self-healing web-film having a light transmittance of 25% or less at a wavelength of 380 to 780 nm. 15. The method of claim 14,
The self-healing web-film has an onset point at a temperature of 10° C. or higher, and the microfibers are irreversibly self-fused to each other at the onset point to increase transparency. 15. The method of claim 14,
The microfiber is a self-healing web-film produced by solution spinning or melt spinning. 15. The method of claim 14,
The self-healing web-film, wherein the average diameter of the fine fibers constituting the self-healing web-film is 0.01 μm to 200 μm. A temperature sensor comprising the self-healing web-film according to claim 14 .

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