Self-repairing polyurethane adhesive, preparation method and application thereof

Abstract

The application provides a self-repairing polyurethane adhesive, raw materials for preparing the polyurethane adhesive include component A and component B; the component A includes polyether polyol and a self-healing agent; the self-healing agent is a thermoplastic polymer material, and the thermoplastic polymer material is mainly a thermoplastic polyester material; and the component B includes aromatic isocyanate. The self-repairing polyurethane adhesive has improved durability, and the application also provides a preparation method and application of the self-repairing polyurethane adhesive.

Description

Technical Field

[0001] This application relates to a self-healing polyurethane adhesive, its preparation method, and its application. Background Technology

[0002] Polyurethane adhesives are widely used in automobile manufacturing due to their excellent mechanical properties, weather resistance, and bonding performance. However, because polyurethane cannot be remelted and reshaped, its service life is often shortened by damage during use. The durability of some existing self-healing polyurethane adhesives still needs further improvement. Summary of the Invention

[0003] This application provides a self-healing polyurethane adhesive that can further improve the self-healing durability of polyurethane.

[0004] This application provides a self-healing polyurethane adhesive, wherein the raw materials for preparing the polyurethane adhesive include component A and component B; component A includes polyether polyol and self-healing agent; the self-healing agent is a thermoplastic polymer material; and component B includes aromatic isocyanate.

[0005] Preferably, the self-healing agent has a melting point of 40-150°C and a number-average molecular weight of 10. 4 ~10 7 g / mol.

[0006] Preferably, the self-healing agent comprises at least one of polycaprolactone, polyvalerol, polybutylene adipate / terephthalate, polybutylene adipate, and polybutylene succinate.

[0007] Preferably, the polyether polyol has a functionality of 2 to 4 and a molecular weight of 1000 to 4000.

[0008] Preferably, the polyether polyol is at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran.

[0009] Preferably, component B comprises an aromatic isocyanate with an average functionality of 2.0–2.7 and an NCO group mass fraction of 23%–40% in the isocyanate.

[0010] Preferably, the mass ratio of component A to component B is 1:(0.4 to 0.7).

[0011] Preferably, the mass ratio of the self-healing agent to the polyether polyol is 1:(3-11).

[0012] Preferably, the aromatic isocyanate is at least one of diphenylmethane diisocyanate, toluene diisocyanate, naphthalene 1,5-diisocyanate, and carbodiimide-modified diphenylmethane diisocyanate.

[0013] Preferably, component A further contains at least one of a catalyst, chain extender, crosslinking agent, light stabilizer, nucleating agent, and pigment.

[0014] Preferably, by mass percentage, component A comprises 70-90% polyether polyol, 2-9% self-healing agent, 2-5% catalyst, 2-5% chain extender, 1-3% crosslinking agent, 1-3% light stabilizer, 1-3% nucleating agent, and 1-2% pigment.

[0015] Preferably, the catalyst comprises an organometallic and / or amine catalyst, wherein the organometallic catalyst comprises at least one selected from dibutyltin dilaurate, stannous octanoate, dimethyltin dilaurate, bismuth isooctanoate, and bismuth laurate; the amine catalyst comprises at least one selected from triethylenediamine, N-methylimidazole, and bis-(3-dimethylaminopropyl)hexahydrotriazine; and the chain extender comprises an aromatic amine chain extender and / or an alcohol chain extender, wherein the aromatic amine chain extender comprises 3,3-dichloro-4,4'-diaminodiphenylmethane, diethyltoluenediamine, and 3 The light stabilizer comprises at least one of 5-dimethylthiotoluenediamine or 2,4-diamino-3-methylthio-5-propyltoluene; the alcohol chain extender comprises at least one of ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol or 1,6-hexanediol; the crosslinking agent comprises at least one of diethanolamine, triethanolamine, and bis-2-(hydroxypropyl)aniline; the light stabilizer comprises bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and / or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate; the nucleating agent comprises silicone oil; and the pigment comprises carbon black.

[0016] The present invention also provides a method for preparing the aforementioned self-healing polyurethane adhesive, wherein component A, the raw material for preparing polyurethane adhesive, is first mixed, and then component B is mixed with component A and heated to react, thereby obtaining polyurethane adhesive.

[0017] Preferably, the reaction temperature of the heating reaction is 90~110℃.

[0018] The present invention also provides an application of the aforementioned self-healing polyurethane adhesive, wherein the polyurethane adhesive is used for surface coatings and / or component articles in at least one of automobiles, electronics, and furniture.

[0019] This application provides a self-healing polyurethane adhesive, the raw materials for which the polyurethane adhesive is prepared include component A and component B; component A includes a polyether polyol and a self-healing agent; the self-healing agent is a thermoplastic polymer; and component B includes an aromatic isocyanate. The polyether polyol and self-healing agent of component A undergo a nucleophilic addition reaction with the functional groups of the aromatic isocyanate of component B, gradually polymerizing to obtain polyurethane. The resulting self-healing polyurethane adhesive has a simpler synthesis process, higher healing efficiency, and rapid response under thermal conditions compared to existing self-healing polyurethane adhesives. This invention uses a thermoplastic polymer as the self-healing agent, which melts and thaws in environments above its glass transition temperature. Utilizing this characteristic, when microcracks appear in the polyurethane material, the thermoplastic healing agent can reflow and fill the cracks through heating or external force. After cooling, the healing agent re-solidifies, achieving a "secondary connection" of the material. This mechanism does not require complex chemical functional group design, and its principle is simple and efficient. The solid self-healing agent introduced in this invention can be melted and reshaped multiple times, and can self-heal more than 10 times, extending the service life of the material. It is also low in cost and suitable for large-scale commercial applications.

[0020] Other features and advantages of this application will be described in detail in the following detailed description section. Detailed Implementation

[0021] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this application.

[0022] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0024] This application provides a self-healing polyurethane adhesive, wherein the raw materials for preparing the polyurethane adhesive include component A and component B; component A includes polyether polyol and self-healing agent; the self-healing agent is a thermoplastic polymer material; and component B includes aromatic isocyanate.

[0025] Preferably, the self-healing agent has a melting point of 40-150°C and a number-average molecular weight of 10. 4 ~10 7 g / mol. The melting point of the self-healing agent is any one or any two of the following: 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 80℃, 125℃, 130℃, 135℃, 140℃, 145℃, and 150℃; the number-average molecular weight of the self-healing agent is 10. 4 ~10 7 g / mol, the number-average molecular weight of the self-healing agent is 10. 4 10 5 10 6 10 7 The value should be within the range of one or both of these parameters. If the melting point parameter of the self-healing agent is too low, it will soften and become sticky at lower temperatures; if the melting point parameter is too high, the viscosity of the adhesive will be too high after melting, making it unable to flow and fill cracks. At the same time, if the number average molecular weight of the self-healing agent is too low, it will weaken the performance of the polyurethane matrix, and the performance of the polyurethane will deteriorate over time; if the number average molecular weight is too high, it will result in excessive viscosity, poor flowability, and inability to fill cracks.

[0026] As some specific embodiments of the present invention, the self-healing agent is at least one of polycaprolactone, polyvalerol, polybutylene adipate / terephthalate, polybutylene adipate, and polybutylene succinate.

[0027] Preferably, the polyether polyol has a functionality of 2 to 4 and a molecular weight of 1000 to 4000. The functionality of the polyether polyol is any one of 2, 3, and 4, or a range between any two; the molecular weight is any one of 1000, 2000, 3000, and 4000, or a range between any two. Excessively high functionality of the polyether polyol leads to excessively high material hardness, brittleness, and decreased toughness and processability. Conversely, excessively low molecular weight leads to abnormal reactivity during synthesis and poor mechanical properties of the material; excessively high molecular weight leads to insufficient reactivity, resulting in low product strength and easy deformation.

[0028] Preferably, the aromatic isocyanate has an average functionality of 2.0–2.7, and the mass fraction of NCO groups in the isocyanate is 23%–40%. Within this range, the resulting polyurethane adhesive exhibits high mechanical strength and good adhesion. The average functionality of the aromatic isocyanate can be any one of 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, and 2.7, or a range between any two; the mass fraction of NCO groups in the isocyanate can be any one of 23%, 25%, 30%, 35%, and 40%, or a range between any two.

[0029] As some specific embodiments of the present invention, the polyether polyol is at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran.

[0030] Preferably, the mass ratio of component A to component B is 1:(0.4 to 0.7). The mass ratio of component A to component B is any one of 1:0.4, 1:0.5, 1:0.6, or 1:0.7, or a range between any two. Within this preferred range, the mass ratio of component A to component B ensures controllable reaction and efficient utilization of raw materials.

[0031] Preferably, the mass ratio of the self-healing agent to the polyether polyol is 1:(3-11). The mass ratio of the self-healing agent to the polyether polyol is any one or any two of 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, and 1:11. Within this preferred range, the material possesses self-healing functionality without compromising the performance of the polyurethane material.

[0032] As some specific embodiments of the present invention, the aromatic isocyanate is at least one of diphenylmethane diisocyanate, toluene diisocyanate, naphthalene 1,5-diisocyanate, and carbodiimide-modified diphenylmethane diisocyanate.

[0033] Preferably, component A further contains at least one of a catalyst, chain extender, crosslinking agent, light stabilizer, nucleating agent, and pigment. Containing at least one of a catalyst, chain extender, crosslinking agent, light stabilizer, and nucleating agent can shorten the reaction time of the self-healing polyurethane adhesive; containing pigment can adjust the color of the self-healing polyurethane adhesive.

[0034] As some specific embodiments of the present invention, by mass percentage, component A comprises 70-90% polyether polyol, 2-9% self-healing agent, 2-5% catalyst, 2-5% chain extender, 1-3% crosslinking agent, 1-3% light stabilizer, 1-3% nucleating agent, and 1-2% pigment.

[0035] As some specific embodiments of the present invention, the catalyst is an organometallic and / or amine catalyst, wherein the organometallic catalyst is at least one selected from dibutyltin dilaurate, stannous octanoate, dimethyltin dilaurate, bismuth isooctanoate, and bismuth laurate; the amine catalyst is at least one selected from triethylenediamine, N-methylimidazole, and bis-(3-dimethylaminopropyl)hexahydrotriazine; the chain extender comprises an aromatic amine chain extender and / or an alcohol chain extender, wherein the aromatic amine chain extender is 3,3-dichloro-4,4'-diaminodiphenylmethane, diethyltoluenediamine, or 3... The light stabilizer is at least one of 5-dimethylthiotoluenediamine or 2,4-diamino-3-methylthio-5-propyltoluene; the alcohol chain extender is at least one of ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol or 1,6-hexanediol; the crosslinking agent is at least one of diethanolamine, triethanolamine or bis-2-(hydroxypropyl)aniline; the light stabilizer is bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and / or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate; the nucleating agent is silicone oil; and the pigment is carbon black.

[0036] The present invention also provides a method for preparing the aforementioned self-healing polyurethane adhesive, wherein component A, the raw material for preparing polyurethane adhesive, is first mixed, and then component B is mixed with component A and heated to react, thereby obtaining polyurethane adhesive.

[0037] In some specific embodiments of the present invention, the reaction temperature of the heating reaction is 90~110℃. The reaction temperature of the heating reaction can be any value among 90℃, 100℃, and 110℃, or any value between two of them. If the heating reaction temperature is too low, the reaction time will be longer, affecting production efficiency; if the heating reaction temperature is too high, the reaction will become violent and uncontrollable.

[0038] The preparation method of the self-healing polyurethane adhesive of the present invention is a common preparation method for those skilled in the art. As one embodiment of the present invention, specifically, the raw material A component of the polyurethane adhesive is first mixed, and then component B is mixed with component A and added into a mold. The mold temperature is between 90 and 110°C, the curing time is 25 seconds to 5 minutes, and then the mold is cooled and demolded. The demolding time is 60 seconds, and the self-healing polyurethane adhesive product is obtained after opening the mold.

[0039] The present invention also provides an application of the aforementioned self-healing material, wherein the self-healing material is used in surface coatings and / or component articles of at least one of automobiles, electronics, and furniture.

[0040] The technical solution of the present invention will be further illustrated below with reference to specific embodiments. All parts, percentages and ratios recorded in the following embodiments are based on weight. All reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing. The instruments used in the embodiments are also commercially available.

[0041] Example 1:

[0042] The raw materials for preparing the polyurethane adhesive include component A and component B; component A includes 72 parts of polyethylene glycol and 8 parts of self-healing agent polycaprolactone, which are mixed for 5 minutes to obtain a mixture; 40 parts of component B diphenylmethane diisocyanate are added to the mixture to obtain the reactant, which is then added to a mold at a temperature of 90°C and cured for 5 minutes before the mold is opened to obtain the polyurethane adhesive product.

[0043] Example 2

[0044] The difference from Example 1 is that component A further contains 3 parts of the organometallic catalyst N-methylimidazolium, 4 parts of the chain extender diethyltoluenediamine, 4 parts of the crosslinking agent triethanolamine, 4 parts of the light stabilizer bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1.5 parts of silicone oil, and 3.5 parts of carbon black. The reactants are added to a mold, the mold temperature is maintained at 90°C, and after curing for 25 seconds, the mold is opened to obtain the polyurethane adhesive product.

[0045] Example 3:

[0046] The raw materials for preparing the polyurethane adhesive include component A and component B; component A includes 60 parts of polypropylene glycol, 20 parts of polybutylene adipate, 3 parts of organometallic catalyst N-methylimidazolium, 4 parts of chain extender diethyltoluenediamine, 4 parts of crosslinking agent triethanolamine, 4 parts of light stabilizer bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1.5 parts of silicone oil, and 3.5 parts of carbon black. After mixing for 5 minutes, a mixture is obtained.

[0047] The mixture is mixed with 32 parts of carbodiimide-modified diphenylmethane diisocyanate (B component) to obtain the reactant. The reactant is then added to a mold at 90°C and cured for 25 seconds before the mold is opened to obtain the polyurethane adhesive product.

[0048] Example 4:

[0049] The raw materials for preparing the polyurethane adhesive include component A and component B; component A includes 100 parts of polytetrahydrofuran, 10 parts of polybutylene succinate, 3 parts of organometallic catalyst N-methylimidazolium, 4 parts of chain extender diethyltoluenediamine, 4 parts of crosslinking agent triethanolamine, 4 parts of light stabilizer bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1.5 parts of silicone oil, and 3.5 parts of carbon black. After mixing for 5 minutes, a mixture is obtained.

[0050] The mixture is mixed with 77 parts of component B, including naphthalene 1,5-diisocyanate, to obtain the reactant. The reactant is then added to a mold, and after curing at 100°C for 25 seconds, the mold is opened to obtain the polyurethane adhesive product.

[0051] Example 5

[0052] The difference from Example 2 is that 8 parts of polycaprolactone were replaced with 8 parts of polybutylene adipate / terephthalate.

[0053] Example 6

[0054] The difference from Example 2 is that 8 parts of polycaprolactone are replaced with 20 parts.

[0055] Example 7

[0056] The difference from Example 2 is that 8 parts of polycaprolactone are replaced with 20 parts of polyvalerol.

[0057] Comparative Example 1

[0058] The difference from Example 1 is that it does not contain the self-healing agent polycaprolactone.

[0059] Comparative Example 2

[0060] The difference from Example 1 is that the self-healing agent is the self-healing capsule of dicyclopentadiene encapsulating the repair agent in Example 1 of patent CN108079916A. The results show that adding 5 wt% of this self-healing microcapsule to the resin matrix results in a self-healing efficiency of 38.1%.

[0061] The components in Examples 1-7 are shown in Table 1:

[0062] Table 1

[0063]

[0064] Self-healing experimental process:

[0065] The polyurethane samples prepared in each embodiment and comparative example were made into rectangular strips. Each sample was cut in half with a knife, and the cut samples were then placed together without pressure along the original cut edges using tweezers. They were then placed at 70-150°C. o In oven C, the samples will self-heal within 5 to 30 minutes, restoring them to their original shape. The self-healing efficiency is calculated as the ratio of the tensile strength of the sample before and after healing. See Table 2 for details.

[0066] Table 2

[0067]

[0068] As shown in Table 2, the self-healing polyurethane adhesives of Examples 1-7 of the present invention exhibit significantly increased self-healing rates and self-healing cycles compared to the polymer-based self-healing composite material containing self-healing microcapsules in Comparative Example 2 of the prior art. When the self-healing polyurethane adhesive of the present invention is used in surface coatings and / or component products of at least one of automobiles, electronics, and furniture, and scratches requiring self-healing occur, self-healing can be achieved simply by using a simple tool such as a hairdryer to heat the scratched area for several minutes, making the process simple and easy to operate.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A self-healing polyurethane adhesive, characterized in that, The raw materials for preparing the polyurethane adhesive include component A and component B; component A includes polyether polyol and self-healing agent; the self-healing agent is a thermoplastic polymer material; the thermoplastic polymer material is mainly a thermoplastic polyester material, and component B includes aromatic isocyanate.

2. The self-healing polyurethane adhesive according to claim 1, characterized in that, The self-healing agent has a melting point of 40-150℃ and a number-average molecular weight of 10. 4 ~10 7 g / mol.

3. The self-healing polyurethane adhesive according to claim 1 or 2, characterized in that, The self-healing agent is at least one of polycaprolactone, polyvalerol, polybutylene adipate / terephthalate, polybutylene adipate, and polybutylene succinate.

4. The self-healing polyurethane adhesive according to claim 1, characterized in that, The polyether polyol has a functionality of 2 to 4 and a molecular weight of 1000 to 4000.

5. The self-healing polyurethane adhesive according to claim 1 or 4, characterized in that, The polyether polyol is at least one of polyethylene glycol, polypropylene glycol, and polytetrahydrofuran.

6. The self-healing polyurethane adhesive according to claim 1 or 4, characterized in that, Component B includes an aromatic isocyanate with an average functionality of 2.0 to 2.7 and a mass fraction of NCO groups of 23% to 40%.

7. The self-healing polyurethane adhesive according to claim 1, characterized in that, The mass ratio of component A to component B is 1:(0.4 to 0.7).

8. The self-healing polyurethane adhesive according to claim 1, characterized in that, The mass ratio of the self-healing agent to the polyether polyol is 1:(3-11).

9. The self-healing polyurethane adhesive according to claim 1, characterized in that, The aromatic isocyanate is at least one of diphenylmethane diisocyanate, toluene diisocyanate, naphthalene 1,5-diisocyanate, and carbodiimide-modified diphenylmethane diisocyanate.

10. The self-healing polyurethane adhesive according to claim 1, characterized in that, Component A also contains at least one of the following: catalyst, chain extender, crosslinking agent, light stabilizer, nucleating agent, and pigment.

11. The self-healing polyurethane adhesive according to claim 10, wherein component A comprises, by weight percentage, 70-90% polyether polyol, 2-9% self-healing agent, 2-5% catalyst, 2-5% chain extender, 1-3% crosslinking agent, 1-3% light stabilizer, 1-3% nucleating agent, and 1-2% pigment.

12. The self-healing polyurethane adhesive according to claim 10, characterized in that, The catalyst is an organometallic and / or amine catalyst, wherein the organometallic catalyst includes at least one selected from dibutyltin dilaurate, stannous octanoate, dimethyltin dilaurate, bismuth isooctanoate, and bismuth laurate; the amine catalyst is at least one selected from triethylenediamine, N-methylimidazole, and bis-(3-dimethylaminopropyl)hexahydrotriazine; the chain extender comprises an aromatic amine chain extender and / or an alcohol chain extender, wherein the aromatic amine chain extender is 3,3-dichloro-4,4'-diaminodiphenylmethane, diethyltoluenediamine, or 3... The light stabilizer comprises at least one of 5-dimethylthiotoluenediamine or 2,4-diamino-3-methylthio-5-propyltoluene; the alcohol chain extender comprises at least one of ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol or 1,6-hexanediol; the crosslinking agent comprises at least one of diethanolamine, triethanolamine, and bis-2-(hydroxypropyl)aniline; the light stabilizer comprises bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate and / or bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate; the nucleating agent comprises silicone oil; and the pigment comprises carbon black.

13. A method for preparing the self-healing polyurethane adhesive according to any one of claims 1-12, characterized in that, First, the raw material component A for preparing polyurethane adhesive is mixed, then component B is mixed with component A, and then heated to react, thus obtaining polyurethane adhesive.

14. The preparation method according to claim 13, wherein the reaction temperature of the heating reaction is 90~110℃.

15. An application of the self-healing polyurethane adhesive according to any one of claims 1-12, wherein the self-healing polyurethane adhesive is used for surface coatings and / or component articles in at least one of automobiles, electronics, and furniture.

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