JP2008239722A - Self-repairing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystalline self-repairing material capable of being produced simply at a low cost and excellent in self-repairing ability and to provide a crystalline self-repairing structure utilizing the same. <P>SOLUTION: The self-repairing material is a crystalline polymer crosslinked product composed of a polymer crosslinked structure and many dangling chains bonded thereto and exhibits characteristics of a near-critical gel which satisfies both of shape retention action resulting from the crosslinked polymer structure and self-repairing action resulting from the dangling chains by the mechanism in which the content of the dangling chains bonded thereto and the inter-crosslink molecular weight are adjusted so as to fall within their respective specific regions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a self-healing material that naturally heals by heating even if a scratch occurs on the surface.

  More specifically, the present invention relates to a crystalline polymer crosslinked body in which a large number of dangling chains are bonded to the polymer crosslinked structure, and the crystallinity that achieves both a material shape retaining action and a wound self-healing action. The present invention relates to a self-healing material, a method for producing the crystalline self-healing material, and a crystalline self-healing structure in which the crystalline self-healing material is immobilized on a substrate.

  The development of intelligent materials that mimic biomaterials is strongly desired in all fields. In particular, a self-healing material that naturally heals and returns to its original state even when a scratch occurs is a characteristic that is not found in conventional artificial structures, and its development is strongly desired. Applications of self-healing materials include skin materials made of various materials such as materials used in places where repair work is difficult, such as outer space and the body.

  Conventionally, as self-healing materials, microcapsules and hollow fillers containing chemical reactants are mixed with specific plastic materials, and the microcapsules and hollow fillers break down at the same time as scratches occur, and the internal chemical reactants become plastic. For example, the following Non-Patent Document 1 to Non-Patent Document 4 have proposed a self-healing material based on a method of repairing a scratched part by spreading inside.

R. P. Wool, “Polymer Interfaces, structure and strength”, p.473, Hanser, 1995. S. R. White, N. R. Sottos, P. H. Geubelle, J. S. Moore, M. R. Kessler, S. R. Sriram, E. N. Brown, S. Viswanathan, Nature, vol. 409, pp. 794-797, (2001). E. N. Brown, S. R. White, N. R. Sottos, S. White, J. Mater. Sci., Vol. 39, pp. 1703-1710 (2004). JWC Pang, IP Bond, Composites Sci. Technol., Vol.65, pp.1791-1799 (2005). Also, by focusing on polyphenylene ether and polycarbonate, and mixing a catalyst that causes a reaction again after degradation. For example, the following non-patent document 5 proposes a method for performing self-repair. In short, the technique of Non-Patent Document 5 is a method in which a main chain of a polymer is recombined using a chemical reaction in a specific type of polymer compound.

K. Takeda, M. Tanahashi, H. Unno, Sci. Technol. Adv. Materials, vol.4, pp.435-444, (2003). For example, the following non-patent document 6 proposes a method of raising the temperature above the transition temperature, and for example, the following non-patent document 7 proposes a method of repairing a scratch by dipping in a specific solvent. ing.

R. P. Wool., "Polymer Interface; Structure and Strength", Chap. 12, Hanser Gardener, Cincinnati, 1994. C. B. Lin, S. Lee, K. S. Liu, Polym. Eng. Sci., Vol. 30, pp. 1399-1406 (1990).

  However, in the methods of Non-Patent Document 1 to Non-Patent Document 4, since it is necessary to include a chemical substance in microcapsules and hollow fillers, and it must be dispersed in plastic, it is inferior in cost performance and technical. It is also difficult. Furthermore, it is considered impossible to repair a scratch generated in the same part of the material repeatedly.

  Furthermore, each of the methods of Non-Patent Document 1 to Non-Patent Document 5 has a problem that the application target is limited to a specific polymer compound.

  Next, in the methods of Non-Patent Documents 6 and 7, the self-repairing action does not appear autonomously, and it is necessary to raise the temperature of the damaged material to a temperature higher than the glass transition temperature or to immerse it in a specific solvent. Therefore, practically it was difficult to apply. In addition, since the method of Non-Patent Document 6 performs self-repair by utilizing diffusion of a linear polymer chain in short, it realizes a practical self-repair speed and fluidization of the material (deformation of self-repair material or There is a fatal problem in practical use that the shape collapse is directly connected.

  Due to these various problems of the prior art, 1) the manufacturing process is excellent in cost performance and technically simple, 2) the application target is not essentially restricted by the type of polymer compound, and 3) self-repairing action. Occurs repeatedly even in the same part of the material, 4) self-healing action is manifested only by heating and without shape collapse, etc. 5) self-healing with advantages such as exhibiting a sufficiently higher elastic modulus than rubber The provision of materials was desired. An object of the present invention is to provide such a self-healing material.

(First invention)
In order to solve the above problems, the first invention of the present application is a crystalline polymer crosslinked body in which a number of dangling chains are bonded to a polymer crosslinked structure, By adjusting the amount of bonding and the molecular weight between cross-linking points of the polymer cross-linked structure within a certain specific region, both the retention of the material shape by the polymer cross-linked structure and the self-healing effect by the dangling chain are compatible. It is a self-healing material that exhibits the properties of a gel in the vicinity of the critical point, and further exhibits a sufficiently higher elastic modulus than rubber because it exhibits crystallinity.

  In the self-healing material of the first invention, the material shape retaining action and the self-healing action are compatible. In the present specification, a crosslinked polymer having such characteristics is referred to as “a gel near the critical point”. The holding action of the material shape is due to the above-described polymer cross-linking structure. On the other hand, the self-repairing action against the wound is due to the dangling chain. As is well known, the dangling chain refers to “a partial chain in which one end is connected to the crosslinked body and the other end is not connected to the crosslinked body”.

  The self-healing mechanism of dangling chains is based on the topology that when the self-healing material is damaged, the dangling chains invade each other in and between the molecules of the polymer cross-linked body and form cohesive force by entanglement. By interaction. Therefore, the time required for self-repair becomes shorter when the temperature is higher. However, even if the self-healing action is promoted by increasing the temperature, as long as the bonding amount of dangling chains and the molecular weight between cross-linking points of the polymer cross-linked structure are adjusted within a certain specific region, the action of retaining the material shape Balances self-healing action with a good balance. This point is decisively different from the case of Non-Patent Document 6 described above.

  In conventional self-healing materials, the concept of near-critical gels for polymer cross-linked materials has never been disclosed, and, moreover, “dangling chain binding amount” or “cross-linking” that defines the formation of gels near critical points. There has never been disclosed or suggested the existence of a specific region for “point-to-point molecular weight”.

  As will be described later, the self-healing material of the first invention can be manufactured by a process that is simple and excellent in cost performance. Moreover, as long as it is a crosslinked polymer exhibiting crystallinity, its application target is not limited by the type of the polymer compound. Next, since the self-healing action is based on the above-described topological interaction, it repeatedly occurs in the same part of the material. Furthermore, the self-healing action is manifested only by heating without causing shape collapse and the like, and at a use temperature, it exhibits a sufficiently higher elastic modulus than rubber to exhibit crystallinity. Thereby, the self-healing material of 1st invention can solve the subject of above-described this invention.

  FIG. 1 schematically shows the self-healing material of the first invention. FIG. 1A shows a state in which a single molecule of the crystalline polymer crosslinked body 1 described above is immobilized on the base material 3 by a chemical reaction at a fixing point 2 having a functional group. As for the molecular crosslinked body 1, its crosslinked structure and a number of dangling chains 4 are visually shown. However, no consideration is given to crystals. FIG. 1B shows a state in which a plurality of molecules of the polymer crosslinked body 1 are densely fixed to the base material 3 at the fixing point 2 to form the coating layer 5. However, FIG. 1 is only a schematic illustration of the self-healing material, and shows specific regions regarding the amount of dangling chains bound to the crystalline polymer crosslinked structure and the molecular weight between crosslinking points of the crystalline polymer crosslinked structure. It is not intended to be exemplary or specific.

  In the crystalline self-healing material of the first invention, the “specific region” relating to the bonding amount of dangling chains and the molecular weight between crosslinking points is the type of polymer, the type of monomer compound forming the polymer, the polymer Since there are various types depending on the content of the cross-linked structure, it is difficult or impossible to uniformly define these specific regions with numerical values. However, as will be described later in the second invention, it is possible to define a specific region that defines the gel in the vicinity of the critical point in terms of the physical properties of the self-healing material.

(Second invention)
The structure of the second invention of the present application for solving the above problem is that the crystalline self-healing material according to the first invention satisfies one or more of the following conditions (a) to (d): Material.
(A) In the measurement of dynamic viscoelasticity, the loss tangent at a temperature 20 ° C. higher than the crystal melting point is in the range of 0.6 to 10.0 at 10 Hz.
(B) In the measurement of dynamic viscoelasticity, the ratio (E10 / E80) of the storage elastic modulus (E10) at a temperature 10 ° C higher than the crystal melting point and the storage elastic modulus (E80) at a temperature 80 ° C higher is 10 Hz. In the range of 2-100.
(C) The gel fraction exceeds 30%.
(D) In the measurement of dynamic viscoelasticity, the storage elastic modulus at the use temperature is 5 × 10 ⁷ Pa or more at 10 Hz.

  In the second invention, a specific region as a gel in the vicinity of the critical point in the crystalline self-healing material according to the first invention is defined in terms of material physical properties and the like.

Although details will be described later, a large loss tangent at a temperature 20 ° C. higher than the crystal melting point under the condition (a) indicates that there are many dangling chains. Under the condition (b), “E10 / E80” is large, that is, a large decrease in storage elastic modulus at a temperature higher than the crystal melting point also means that there are many dangling chains. In the condition of (c), the gel fraction means [[weight after drying] / [weight before immersion] × 100 (%)], but the gel fraction is less than 30%. It means that there are many sols whose ends are not connected to the crosslinked body, and in this case, shape retention is often impaired during heating. In the measurement of dynamic viscoelasticity under the condition (d), the storage elastic modulus at use temperature of 5 × 10 ⁷ Pa or more at 10 Hz means that the elastic modulus is sufficiently higher than that of rubber, and the hardness High self-healing material.

(Third invention)
The configuration of the third invention of the present application for solving the above problems is that the polymer crosslinked product according to the first invention or the second invention is a polyester resin, a polyamide resin, a polycarbonate resin, a polyurethane resin, a polyether resin, an epoxy resin, It is a self-healing material comprising a blend material of one or more of polyimide resin, polyolefin resin, polystyrene resin, saturated rubber, unsaturated rubber, or other resin / rubber.

  As described above, the resin species of the crosslinked polymer constituting the self-healing material is not essentially limited, but preferred examples include those listed in the third invention. The elastic modulus of the self-healing material is mainly determined by the degree of crystallinity of the polymer crosslinked body, and can be controlled by a value ranging from rubber to the elastic modulus of a general crystalline polymer.

(Fourth invention)
The structure of the fourth invention of the present application for solving the above-described problems is that, if necessary, a catalyst is used, and certain first compounds and second compounds are defined as defined in the following (1) to (3). Or a method for producing a self-healing material, wherein a certain first compound to third compound are mixed and reacted at a predetermined reaction ratio to produce the self-healing material according to any of the first to third inventions. It is.

  (1) Functional group A includes a first compound having three or more functional groups A in one molecule and a second compound having two or more functional groups B specifically binding to functional group A in one molecule. / Reaction ratio of functional group B (refers to the ratio of the number of moles of functional groups involved in the reaction; the same shall apply hereinafter) is mixed and reacted at 0.3 to 0.7. The first compound and / or the second compound exhibit crystallinity.

  (2) a first compound having three or more functional groups A in one molecule, a second compound having two or more functional groups B specifically binding to the functional group A in one molecule, and a functional group A A third compound having two in one molecule is mixed and reacted at a functional group A / functional group B reaction ratio of 0.4 to 0.8. However, the number of moles of the functional group A derived from the first compound occupies 25% or more of the total number of moles of the functional group A. The first compound and / or the second compound exhibit crystallinity.

  (3) The functional group A includes a first compound having three or more functional groups A in one molecule and a second compound having three or more functional groups B specifically binding to the functional group A in one molecule. / The reaction ratio is 0.1 to 0.6 in the reaction ratio of the functional group B. The first compound and / or the second compound exhibit crystallinity.

The fourth invention provides a method for producing the self-healing material according to any of the first to third inventions easily and at low cost.

In the fourth invention described above, the reaction can also be caused in a solvent. After completion of the reaction, the solvent can be dried to obtain the target composition.

  As described above, the self-healing material of the first invention which is a “gel in the vicinity of the critical point” is difficult or impossible to uniformly define the specific region defining the same from the structural aspect as described above. However, while it can be defined from the viewpoint of material properties as in the second invention, it can also be defined by the manufacturing conditions as in the fourth invention.

(Fifth invention)
The structure of the fifth invention of the present application for solving the above problem is that in the method (1) for producing a self-healing material according to the fourth invention, the first compound has three or more isocyanate groups as the functional group A in one molecule. In the case where the second compound is a crystalline polymer polyol having two or more hydroxyl groups in one molecule and the manufactured self-healing material is a polyurethane resin, the reaction of isocyanate group / hydroxyl group This is a method for producing a self-healing material in which a first compound and a second compound are mixed and reacted at a ratio of 0.3 to 0.7.

  The fifth invention provides an example of a particularly preferred embodiment of the polyurethane resin among the methods for producing the self-healing material of the fourth invention. When a polyurethane is produced from a polyester diol having a molecular weight of 2000 and an isocyanurate-modified product of a diisocyanate compound, the isocyanate group / hydroxyl group reaction ratio is particularly preferably 0.50 or a value in the vicinity thereof.

(Sixth invention)
The structure of the sixth invention of the present application for solving the above problem is a self-healing structure in which the self-healing material according to any one of the first to third inventions is fixed on a substrate. Here, the form of “immobilization” is not limited, but as a typical form thereof, the molecular chain of the crosslinked polymer constituting the self-healing material is chemically bonded to the substrate at one place or plural places. The form can be mentioned.

  The use form of the crystalline self-healing material according to the first to third inventions is not limited, but the use form as a self-healing structure in which the self-healing material is fixed on the substrate as in the sixth invention. It is particularly useful.

  The type of the base material is not particularly limited as long as it has a means capable of immobilizing the polymer crosslinked body. For example, a base material made of a polymer material is preferably used. For the purpose of increasing the reactive functional group on the substrate surface, it is also preferable to perform a surface treatment such as corona discharge on the surface of the substrate. The thickness of the crosslinked polymer constituting the self-healing material is preferably in the range of 0.01 mm to 10 mm.

If the thickness of the polymer crosslinked body is less than 0.01 mm, there is a problem that the received scratches easily reach a substrate having no self-repairing property. When the thickness of the polymer crosslinked body exceeds 10 mm, the mechanical properties of the base material are greatly impaired and the self-healing material is easily wasted.

  The crystalline self-healing material of the present invention is 1) the manufacturing process is excellent in cost performance and technically simple, 2) the application object is not essentially restricted by the type of polymer compound, and 3) the self-healing action is a material. 4) It occurs repeatedly even in the same part of 4), 4) It exhibits a self-repairing effect only by heating, without causing shape collapse, etc. 5) It has an excellent advantage such as a sufficiently higher elastic modulus than rubber.

  Next, modes for carrying out the present invention will be described including the best mode.

[Self-healing materials]
The crystalline self-healing material according to the present invention is a crosslinked crystalline polymer in which a number of dangling chains are bonded to the polymer crosslinked structure. And the characteristic of a near-critical gel is shown by adjusting the bonding amount of the dangling chain to the polymer crosslinked structure and the molecular weight between crosslinking points of the polymer crosslinked structure within a specific region. Here, the characteristic of the gel in the vicinity of the critical point means that the holding action of the material shape and the self-repairing action are compatible at the crystalline melting point or higher.

The crystalline self-healing material according to the present invention may be defined as satisfying one or more of the following conditions (a) to (d) from the viewpoint of physical properties and the like.
(A) Loss tangent at a temperature 20 ° C. higher than the crystal melting point in the measurement of dynamic viscoelasticity is in the range of 0.6 to 10.0.
(B) The ratio (E10 / E80) of the storage elastic modulus (E10) at a temperature 10 ° C. higher than the crystal melting point and the storage elastic modulus (E80) at a temperature 80 ° C. higher than the crystal melting point is 2 to Within the range of 100.
(C) The gel fraction exceeds 30%.
(D) In the measurement of dynamic viscoelasticity, the storage elastic modulus at the use temperature is 5 × 10 ⁷ Pa or more at 10 Hz.

  The conditions (a) to (d) will be described in more detail as follows.

  The crosslinked crystalline polymer used for the self-healing material has a loss tangent at a temperature 20 ° C. higher than the crystal melting point in the range of 0.6 to 10.0, more preferably in the range of 0.65 to 5.0. Of these, more preferably within the range of 0.7 to 3.0. If the loss tangent at this temperature is less than 0.6, self-repairability is not exhibited, and if it exceeds 10.0, it is difficult to maintain the shape. Further, when the loss tangent at a temperature 50 ° C. higher than the crystal melting point is in the range of 0.5 to 10.0, the self-repairing property is further improved.

The crystal melting point in the present invention is a temperature at which the tensile loss elastic modulus rapidly decreases in the measurement of dynamic viscoelasticity. In the present invention, for convenience, the tensile storage elastic modulus is 1 × 10 ⁷ at a frequency of 10 Hz. The temperature is defined as Pa. The tensile storage modulus can be easily measured with a commercially available forced vibration type dynamic viscoelasticity measuring apparatus.

  The crosslinked polymer used in the crystalline self-healing material of the present invention has a ratio between the storage elastic modulus (E10) at a temperature 10 ° C higher than the crystalline melting point and the storage elastic modulus (E80) at a temperature 80 ° C higher. “E10 / E80” is in the range of 2 to 100, more preferably in the range of 2 to 80. If E10 / E80 is less than 2, self-repairing properties are not exhibited, and if it exceeds 100, it is difficult to maintain the shape.

  A large decrease in storage modulus at a temperature higher than the crystalline melting point means that there are many dangling chains. The dangling strand exhibits a repair property to the wound due to the above-described action. However, if the storage elastic modulus decreases too much, the temperature dependence of the elastic modulus becomes excessive, which may cause a practical problem.

  The crosslinked crystalline polymer used in the self-healing material of the present invention has a gel fraction [[weight after drying] / [weight before immersion] × 100 (%)] of 30%, more preferably 50%, More preferably, it exceeds 80%. If the gel fraction is less than 30%, shape retention may be impaired during heating.

  The low gel fraction of the crosslinked crystalline polymer means that the amount of sol whose both ends are not connected to the crosslinked body increases. Since the sol component exhibits fluidity, it is difficult to use it as a material.

The crosslinked crystalline polymer used in the crystalline self-healing material of the present invention has a storage elastic modulus at use temperature of 5 × 10 ⁷ Pa or more, preferably 1 × 10 ⁸ Pa at 10 Hz, as measured by dynamic viscoelasticity. Thus, a material having a high surface hardness and a high elastic modulus can be obtained.
The crystallinity of the crosslinked crystalline polymer is not particularly limited, and it is preferable to set a high crystallinity for a material with high hardness and a low crystallinity for a material with low hardness. However, in order to significantly reduce the surface adhesion, it is desirable that the crystallinity is 10% or more. The degree of crystallinity is calorimetric if the heat of fusion of the complete crystal is known (crystallinity = heat of fusion of the sample / heat of fusion of the complete crystal), and the density of the complete crystal and amorphous is known. Measurement (crystallinity = (sample density−amorphous density) / (crystal density−amorphous density)) or wide angle X-ray diffraction measurement (crystallinity = (total crystal peak area) / (Total sum of crystal peak areas + area of amorphous peaks)).

  Furthermore, it is desirable that the crystalline polymer crosslinked material used in the crystalline self-healing material of the present invention has a crystal melting point of 30 ° C. or higher, and thus a material having a high elastic modulus can be obtained even at room temperature.

  The self-healing behavior in the crystalline self-healing material of the present invention is due to entanglement interaction involving dangling chains that become active above the crystalline melting point. Since the formation of the entanglement interaction becomes intense above the crystalline melting point, it is necessary to leave the material at a temperature higher than the crystalline melting point in order to cause self-healing properties. Thereafter, by cooling to the use temperature, crystallization occurs again, and a high elastic modulus is exhibited. A method for reaching a temperature higher than the crystal melting point is arbitrary, and is not particularly limited. For example, there are methods such as leaving in an oven, ironing, and soaking in hot water.

  The resin type of the crystalline self-healing material is not limited as long as a polymer crosslinked body can be formed, but since the reaction can be easily controlled, polyester resin, polyamide resin, polycarbonate resin, polyurethane resin, polyether resin It is preferably composed of one or more of epoxy resin, polyimide resin, polyolefin resin, polystyrene resin, saturated rubber and unsaturated rubber. In some cases, blend materials of these self-healing materials and other materials (resin / rubber) that are not self-healing materials can also be used.

[Method of manufacturing self-healing material]
The crystalline self-healing material of the present invention can be produced by the method of the fourth invention. That is, if necessary, a predetermined first compound and a second compound, or a predetermined first compound to a third compound, as defined in the following (1) to (3), using a catalyst. The above self-healing material is produced by mixing and reacting at a reaction ratio of (the ratio of the number of moles of functional groups involved in the reaction; the same applies hereinafter).

  (1) Functional group A includes a first compound having three or more functional groups A in one molecule and a second compound having two or more functional groups B specifically binding to functional group A in one molecule. / The reaction is carried out with a functional group B reaction ratio of 0.3 to 0.7. The first compound and / or the second compound exhibit crystallinity.

  (2) a first compound having three or more functional groups A per molecule, a second compound having two or more functional groups B specifically binding to the functional group A, and a functional group A A third compound having two in one molecule is mixed and reacted at a functional group A / functional group B reaction ratio of 0.4 to 0.8. However, the number of moles of the functional group A derived from the first compound occupies 25% or more of the total number of moles of the functional group A. The first compound and / or the second compound exhibit crystallinity.

  (3) The functional group A includes a first compound having three or more functional groups A in one molecule and a second compound having three or more functional groups B specifically binding to the functional group A in one molecule. / The reaction ratio is 0.1 to 0.6 in the reaction ratio of the functional group B. The first compound and / or the second compound exhibit crystallinity.

  In this method, the first compound to the third compound mean so-called monomers. As the combination of functional group A / functional group B, isocyanate group / hydroxyl group, isocyanate group / amino group, carboxyl group / amino group, carboxyl group / hydroxyl group, carboxyl group / glycidyl group, carboxyl group / oxazoline group, maleic anhydride / Examples include oxazoline group, maleic anhydride / amino group, glycidyl group / oxazoline group, isocyanate group / oxazoline group and the like. The “catalyst used when necessary” may be appropriately selected from those well known in the polymerization reaction system of the first compound to the third compound. For example, dibutyltin dilaurate is widely used in polyurethane polymerization systems, and titanium compounds are widely used in polyester polymerization systems.

  From the viewpoint of the advantage of the method for producing the crystalline self-healing material, the polyurethane resin is particularly preferable because it is easy to handle. In particular, as described above in the fifth invention, a polyurethane-based resin obtained from a polyisocyanate compound having three or more isocyanate groups in one molecule and a crystalline polymer polyol having two or more hydroxyl groups in one molecule, It is preferable because the raw material has low toxicity and is excellent in handling. In particular, it is known that a crystalline polyester polyol obtained by polycondensation of ethylene glycol or butylene glycol and adipic acid is excellent in cost performance.

  Examples of the isocyanate compound having three or more isocyanate groups include 2,4- and 2,6-tolylene diisocyanate, m- and p-phenylene diisocyanate, 1-chlorophenylene-2,4-diisocyanate, 1, 5-naphthalene diisocyanate, methylene bisphenylene 4,4'-diisocyanate, m- and p-xylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, 4,4'-methylenebiscyclohexyl diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, etc. Diisocyanate trimer, 1,6,11-undecane triisocyanate, lysine ester triisocyanate, 4-isocyanatomethyl-1,8-octamethyldiisocyanate Over preparative such polyfunctional isocyanates such as triisocyanates or polyphenyl methane polyisocyanate it can be mentioned, and one or more of these can be used.

  Moreover, it is also possible to use together said diisocyanate. However, in this case, it is desirable that the number of NCO groups in triisocyanate is 0.25 or more with respect to the number of NCO groups in all isocyanates. If it is less than 0.25, the shape may not be retained due to insufficient crosslinking density.

  Examples of the polymer polyol having two or more hydroxyl groups in one molecule include polyester polyols, polyether polyols, polycarbonate polyols, castor oil polyols, polyolefin polyols such as saponified EVA (ethylene-vinyl acetate copolymer), A cellulose, a cellulose derivative, etc. are mentioned, These 1 type (s) or 2 or more types are used. However, in the case of reacting with a polyisocyanate compound having three or more isocyanate groups in one molecule, since many polyisocyanate compounds are amorphous, the polymer polyol needs to exhibit crystallinity.

  The molar ratio of the NCO group and hydroxyl group of the isocyanate compound to be used is within the range of 0.3 to 0.7, more preferably 0.4 to 0.6 when the polymer polyol has two hydroxyl groups. Within range. If this molar ratio is less than 0.3, even if only triisocyanate is used as the isocyanate, the shape may not be maintained due to insufficient crosslinking density, and if it exceeds 0.7, self-repairability may not be exhibited.

[Self-healing structure]
The crystalline self-healing structure of the present invention is obtained by fixing any of the above self-healing materials on a substrate. In this case, the self-healing material can be preferably used, for example, as the skin of the substrate.

  The type of the base material of the crystalline self-healing structure is not particularly limited as long as it has a means capable of immobilizing the crosslinked polymer constituting the self-healing material by chemical bonding or the like. In the case of immobilizing the crosslinked polymer by chemical bonding, it is necessary to have a functional group that generates chemical bonding, and a polymer material base material is preferably used. As the base material of the polymer material, for example, polyester resin, polyamide resin, cellulose and cellulose derivatives, polyurethane resin, polycarbonate resin, polyether resin, polyimide resin, various rubbers and the like are preferably used.

  In addition, for the purpose of increasing the reactive functional group on the surface, the surface of the above plastic and rubber substrate is subjected to corona discharge treatment, and further on the surface of polyolefin resin, polyvinyl chloride resin, polystyrene resin, acrylic resin. It is also possible to use one subjected to corona discharge treatment.

  In the crystalline self-healing structure, the thickness of the crystalline polymer crosslinked body is preferably within a range of 0.01 mm to 10 mm. If the thickness of the crosslinked crystalline polymer is less than 0.01 mm, the scratches on the surface may reach a substrate that does not exhibit self-healing properties. On the other hand, if the thickness of the crosslinked crystalline polymer exceeds 10 mm, the mechanical properties of the base material are greatly impaired, and the material is wasted and the cost performance is likely to be inferior.

  A crosslinked crystalline polymer before chemically bonding to the substrate or a crystalline self-repairing structure obtained by chemically bonding the substrate and the crosslinked polymer is once immersed in an excess organic solvent. It is also possible to dissolve the sol component contained therein in the solvent. By treating with an organic solvent, it is possible to improve shape retention.

  The crystalline self-healing material of the present invention can be preferably used for, for example, a high-grade skin material that dislikes surface scratches.

  Examples of the present invention and comparative examples will be described below. The technical scope of the present invention is not limited by these examples and comparative examples.

[Measurements in Examples and Comparative Examples]
1) Measurement of storage elastic modulus and loss tangent The storage elastic modulus and loss tangent of the polymer crosslinked product and the substrate were measured in a linear region using a forced vibration type dynamic viscoelasticity measuring apparatus (UBM, E4000). . The measurement frequency was 10 Hz, the temperature increase rate was 2 ° C./min, a sine wave was applied, and measurement was performed in the tensile mode. The glass transition temperature was a temperature at which the loss elastic modulus was maximum in the glass-rubber transition region. The crystal melting point was a temperature at which the storage elastic modulus was 1 × 10 ⁷ Pa. Loss tangent (tan δ) at temperatures 20 ° C. and 50 ° C. higher than the crystalline melting point, and ratio of storage elastic modulus at temperatures 10 ° C. and 80 ° C. higher than the crystal melting point [E (10) / E (80)], crystal melting point, glass transition temperature, and storage elastic modulus at room temperature.

2) Measurement of gel fraction and degree of swelling A polymer crosslinked body whose weight was measured in advance was immersed in excess acetone and allowed to stand at room temperature for 24 hours. Then, the solvent was removed with a vacuum dryer and the dry weight was measured. [Weight after drying] / [Weight before immersion] × 100 (%) was determined as a gel fraction.

3) Measurement of crystallinity Using a wide-angle X-ray diffractometer (Rigaku), diffraction peaks were measured at a scan rate of 1 ° / min from 2θ to 8 ° to 32 °. The measurement temperature was room temperature, and the tube current was 40 mA and the tube voltage was 40V. The obtained peaks were separated by commercially available software, and divided into a plurality of crystal peaks and one amorphous peak. A value obtained by dividing the sum of the areas of the crystal peaks by (the sum of the areas of the crystal peaks + the area of the amorphous peaks) was defined as the crystallinity.

4) Evaluation of self-healing property The polymer crosslinked body was cut into 30 mm × 10 mm, and completely broken from the center using a razor at room temperature. Thereafter, an iron at 140 ° C. was applied for 5 seconds to melt the cut surface. The sample was turned upside down, and the same operation was performed. Then, the sample was placed in a freezer at an internal temperature of −20 ° C. and left for 1 day. After visually confirming the degree of repair of the scratch, the cut part was bent and the repair situation was examined.

5) Evaluation of shape retention The crosslinked polymer was cut into 30 mm × 10 mm, left in an oven at 140 ° C. for 1 hour, and the state of the test piece was visually observed.

[Example 1]
Crystalline polyester diol composed of ethylene glycol and adipic acid (Nippon Polyurethanes Co., Ltd., trade name Nipporan 4040, number average molecular weight 2000) and hexamethylene diisocyanate trimer (Nippon Polyurethanes Co., Ltd., trade name Coronate HX) Were mixed at a reaction ratio of [NCO] / [OH] of 0.50, and 100 ppm of dibutyltin dilaurate was further mixed as a catalyst. After defoaming with a vacuum dryer at room temperature, it was poured over polytetrafluoroethylene and heated at 150 ° C. for 8 minutes to carry out a urethane reaction, thereby obtaining a target sample.
The thickness of the crosslinked body was 0.7 mm. Self-healing properties and various physical properties were measured using the obtained samples.

[Comparative Example 1]
A sample was obtained in exactly the same manner as in Example 1 except that an amorphous polymer polyol (manufactured by Nippon Polyurethane Co., Ltd., trade name NIPPOLAN 152, number average molecular weight 2000) was used, and various measurements were performed.

[Comparative Example 2]
Polymer polyol (Nippon Polyurethane Co., Ltd., trade name NIPPOLAN 4040, number average molecular weight 2000) and hexamethylene diisocyanate trimer (Nippon Polyurethanes Co., Ltd., trade name Coronate HX) are [NCO] / [OH]. A sample was obtained in the same manner as in Example 1 except that the reaction ratio was 0.80, and various measurements were performed.

[Evaluation results of Example 1 and Comparative Examples 1 and 2]
The evaluation results of various measurements in Example 1 and Comparative Examples 1 and 2 are shown in Table 1 below.

The state of self-healing of the scratches given to the crosslinked body (self-healing material of the present invention) according to Example 1 is shown by the photographs in FIGS. FIG. 2 shows a state in which a cut (completely cut state) is given, and FIGS. 3 and 4 show a state in which the cut after applying a 140 ° C. iron for 5 seconds is completely self-repaired.

  According to the present invention, a crystalline self-healing material having various advantages over the prior art and a self-healing structure using the material can be manufactured easily and at low cost.

It is a figure which shows typically the structure of the self-healing material of this invention.

It is a photograph which shows the mode of the restorability evaluation of the self-healing material which concerns on the Example of this invention.

It is a photograph which shows the mode of the restorability evaluation of the self-healing material which concerns on the Example of this invention.

It is a photograph which shows the mode of the restorability evaluation of the self-healing material which concerns on the Example of this invention.

Explanation of symbols

1 Polymer crosslinked body 2 Fixing point 3 Base material 4 Dangling chain 5 Coating layer

Claims (6)

A crystalline polymer crosslinked product in which a number of dangling chains are bonded to the polymer crosslinked structure. When the crystalline melting point or higher, the amount of dangling chains bonded to the polymer crosslinked structure and the polymer crosslinked structure By adjusting the molecular weight between cross-linking points within a certain specific region, it shows gel characteristics near the critical point where both the retention of the material shape and the self-healing action are compatible, and it must be used below the crystalline melting point. Characteristic crystalline self-healing material. The self-healing material according to claim 1, wherein the self-healing material satisfies one or more of the following conditions (a) to (d).
(A) In the measurement of dynamic viscoelasticity, the loss tangent at a temperature 20 ° C. higher than the crystal melting point is in the range of 0.6 to 10.0 at 10 Hz.
(B) In the measurement of dynamic viscoelasticity, the ratio (E10 / E80) of the storage elastic modulus (E10) at a temperature 10 ° C higher than the crystal melting point and the storage elastic modulus (E80) at a temperature 80 ° C higher is 10 Hz. In the range of 2-100.
(C) The gel fraction exceeds 30%.
(D) In the measurement of dynamic viscoelasticity, the storage elastic modulus at the use temperature is 5 × 10 ⁷ Pa or more at 10 Hz. The polymer crosslinked product is one or more of polyester resin, polyamide resin, polycarbonate resin, polyurethane resin, polyether resin, epoxy resin, polyimide resin, polyolefin resin, polystyrene resin, saturated rubber, and unsaturated rubber. The self-repairing material according to claim 1, wherein the self-repairing material is made of a blend material of a resin / rubber of other types. If necessary, using a catalyst, the prescribed first compound and the second compound, or the prescribed first compound to the third compound are subjected to a predetermined reaction as defined in the following (1) to (3). A method for producing a self-healing material, wherein the self-healing material according to any one of claims 1 to 3 is produced by mixing and reacting at a ratio.
(1) Functional group A includes a first compound having three or more functional groups A in one molecule and a second compound having two or more functional groups B specifically binding to functional group A in one molecule. / The reaction is carried out with a functional group B reaction ratio of 0.3 to 0.7. The first compound and / or the second compound exhibit crystallinity.
(2) a first compound having three or more functional groups A per molecule, a second compound having two or more functional groups B specifically binding to the functional group A, and a functional group A A third compound having two in one molecule is mixed and reacted at a functional group A / functional group B reaction ratio of 0.4 to 0.8. However, the number of moles of the functional group A derived from the first compound occupies 25% or more of the total number of moles of the functional group A. The first compound and / or the second compound exhibit crystallinity.
(3) The functional group A includes a first compound having three or more functional groups A in one molecule and a second compound having three or more functional groups B specifically binding to the functional group A in one molecule. / The reaction ratio is 0.1 to 0.6 in the reaction ratio of the functional group B. The first compound and / or the second compound exhibit crystallinity. In the above (1), the first compound is a polyisocyanate compound having three or more isocyanate groups as the functional group A in one molecule, and the second compound is a crystalline polymer polyol having two or more hydroxyl groups in one molecule. Yes, when the self-healing material to be manufactured is a polyurethane resin, the first compound and the second compound are mixed and reacted at a reaction ratio of isocyanate group / hydroxyl group of 0.3 to 0.7. The manufacturing method of the self-healing material of Claim 4. A self-healing structure, wherein the self-healing material according to any one of claims 1 to 3 is immobilized on a substrate.

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