UV curing self-repairing self-adhesive polyurethane resin and preparation method and application thereof

Abstract

The present invention discloses a preparation method and application of a UV-cured self-repairing self-adhesive polyurethane resin, and belongs to the technical field of functional polyurethane materials. The preparation method of the polyurethane resin of the present invention is as follows: (1) adding diisocyanate and polyol to a reaction vessel, dripping a catalyst, heating the reaction until NCO reaches theory, adding 1,4-butanediol, heating the reaction, and obtaining a polyurethane prepolymer; (2) adding polyetheramine to the polyurethane prepolymer prepared in step (1) to react, and obtaining a partially polyether-terminated polyurethane; (3) adding hydroxyethyl acrylate to the polyurethane prepared in step (2) for end-capping treatment, and obtaining a light-cured polyurethane elastic resin. The UV-cured polyurethane resin prepared by the present invention has a greater improvement in mechanical properties than traditional end-capped resins, and has good self-repairing properties and certain bonding properties to different substrates.

Description

Technical Field

[0001] The invention relates to the technical field of functional polyurethane materials, and in particular to a UV-cured self-repairing self-adhesive polyurethane resin and a preparation method and application thereof. Background Art

[0002] With the rapid development of my country's social economy, the demand for resources is increasing, which has brought huge environmental pressure. Compared with traditional solvent-based resins, UV-curable resins have attracted widespread attention and have broad application prospects as soon as they were launched due to their fast curing speed, low VOC emissions, good energy-saving and environmental protection effects.

[0003] Pure linear polyurethane resin is cheap and has a good cost performance ratio, but the current preparation method is relatively simple and the performance (such as strength, elongation, etc.) in many applications cannot be met. In order to solve the above problems, it is necessary to develop a UV curable self-healing self-adhesive polyurethane resin. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for preparing and applying a UV-curable self-repairing self-adhesive polyurethane resin. The light-curable polyurethane resin prepared by the present invention has greatly improved mechanical properties compared to traditional double-bond terminated resins, and has good self-repairing and bonding properties.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing a UV-curable self-repairing self-adhesive polyurethane resin comprises the following steps:

[0007] (1) Add diisocyanate and polyol into a reaction container, add a catalyst dropwise, heat the reaction until -NCO reaches theoretical value, add 1,4-butanediol, heat the reaction to 60-70°C for chain extension reaction for 2-3h to obtain a polyurethane prepolymer;

[0008] (2) adding polyetheramine to the polyurethane prepolymer prepared in step (1) to react and obtain a partially polyether-terminated polyurethane;

[0009] (3) Add hydroxyethyl acrylate to the polyurethane prepared in step (2) and perform end-capping treatment to obtain a UV-curable self-repairing self-adhesive polyurethane resin.

[0010] Furthermore, in step (1), the diisocyanate is isophorone diisocyanate or hexamethylene diisocyanate. The polyol is polytetramethylene ether diol with a molecular weight of 2000.

[0011] Furthermore, in step (1), the catalyst is one of dibutyltin dilaurate, an organic bismuth catalyst, and dimethylcyclohexylamine.

[0012] Furthermore, in step (1), the molar ratio of the diisocyanate to the polyol is 2:1; and the amount of the catalyst added is 0.09 to 0.32% of the total mass of the diisocyanate and the polyol.

[0013] Furthermore, in step (1), the temperature is raised to 40-50° C. at a rate of 2-3° C. / min and then reacted for 2-3 hours.

[0014] Furthermore, in step (1), the molar ratio of 1,4-butanediol to diisocyanate is 0.25:1

[0015] Furthermore, in step (2), the polyetheramine is a monofunctional polyetheramine with a molecular weight of 1000; the molar ratio of the polyetheramine to the diisocyanate is 0.1 to 0.5:1; the reaction temperature is 60 to 70° C., and the reaction time is 0.5 to 1 h.

[0016] Furthermore, in step (3), the molar ratio of hydroxyethyl acrylate to diisocyanate is 0.1-0.5:1; the reaction temperature is 80-90° C., and the reaction time is 2-3 hours.

[0017] A UV-curable self-repairing self-adhesive polyurethane resin prepared by the preparation method, wherein the elongation at break is 400-1300%.

[0018] An application of the UV-curable self-repairing self-adhesive polyurethane resin, wherein the UV-curable self-repairing self-adhesive polyurethane resin is used to prepare a polyurethane adhesive.

[0019] Furthermore, the polyurethane adhesive comprises the following components by mass percentage: 70% of the above-mentioned photocurable polyurethane elastic resin; 10% of isobornyl acrylate and 20% of tetrahydrofurfuryl acrylate.

[0020] The UV-curable self-repairing self-adhesive polyurethane resin prepared by the preparation method has greatly improved mechanical properties, good self-repairing properties and certain bonding properties to different substrates, and has broad application prospects in the field of light curing.

[0021] The beneficial technical effects of the present invention are:

[0022] (1) The present invention prepares a polyurethane prepolymer using diisocyanate, polyol and chain extender as raw materials; then, a monofunctional polyetheramine is added to semi-end-cap the prepolymer, thereby connecting a long straight chain to the main chain of the resin to replace acrylate, improving the flexibility of the chain segment, and presenting an increase in elongation on a macro scale. Finally, hydroxyethyl acrylate is used to end-cap the remaining -NCO in the polyurethane, and C=C is connected to provide a site for cross-linking with a photoinitiator, providing a basis for subsequent photocuring.

[0023] (2) The UV-curable self-healing self-adhesive polyurethane resin prepared by the method of the present invention makes up for the deficiencies in the mechanical properties of the traditional bifunctional photocurable polyurethane resin. The polyetheramine itself has a highly flexible ether bond (-COC-), which provides excellent mechanical performance support for the system; and the special structure of the single-NH2 end cap can also ensure that the main resin has good stability after the PEA end cap is connected. The polyetheramine end cap is connected to the polyurethane system, and a dynamically reversible urea group is introduced; and the cross-linked structure formed is comb-shaped, and hydrogen bonds and urea groups can be enriched on the resin surface, so that the resin has certain self-healing properties and self-adhesive properties, and has good application prospects in the field of photocurable polyurethane materials.

[0024] (3) The photocurable polyurethane resin prepared by the present invention is used for preparing an adhesive. The preparation method is simple, and the prepared adhesive has good bonding performance to the PET film. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The mechanical properties of the photocurable polyurethane resins prepared in Examples 1-4 of the present invention.

[0026] Figure 2 This is a graph showing the adhesion of the photocurable polyurethane resin prepared in Example 1 of the present invention to different substrates.

[0027] Figure 3 The mechanical properties of the photocurable polyurethane resin prepared in Example 1 of the present invention for adhesion to different substrates.

[0028] Figure 4 This is a test chart of the self-healing performance of the photocurable polyurethane resin prepared in Example 1 of the present invention.

[0029] Figure 5 This is a graph showing the shear strength of the adhesives prepared in Application Examples 1-4 of the present invention on PET film. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0031] Example 1

[0032] UV curing self-repairing self-adhesive polyurethane resin, the preparation method thereof comprises the following steps:

[0033] (1) 13.32 g (0.06 mol) of isophorone diisocyanate (IPDI) and 60 g (0.03 mol) of polytetramethylene glycol (PTMG) were added to a dry three-necked flask equipped with a stirrer, a condenser, and a thermometer; 0.073 g of catalyst dibutyltin dilaurate (DBTDL) was added, and the temperature was raised to 45°C at 3°C / min. After the temperature was reached, the reaction was continued for 2 h; 1.35 g (0.015 mol) of 1,4-butanediol (BDO) was added, the temperature was raised to 60°C, and the reaction was continued for 3 h to obtain a polyurethane prepolymer.

[0034] (2) 15 g (0.015 mol) of monofunctional polyetheramine was added into the three-necked flask and reacted at 60° C. for 1 h to obtain a semi-blocked polyurethane resin.

[0035] (3) 1.74 g (0.015 mol) of hydroxyethyl acrylate (HEA) was added into the three-necked flask, and the temperature was raised to 80° C. and reacted for 3 h to obtain a UV-curable self-healing self-adhesive polyurethane resin having dual end-capping of the designed polyether and HEA.

[0036] The end-capping content of the polyetheramine prepared in Example 1 accounts for 50% of the molar number of the terminal groups of the entire elastic resin.

[0037] Example 2

[0038] UV curing self-repairing self-adhesive polyurethane resin, the preparation method thereof comprises the following steps:

[0039] (1) Add 6.66 g (0.03 mol) of isophorone diisocyanate (IPDI) and 30 g (0.015 mol) of polytetramethylene glycol (PTMG) into a dry three-necked flask equipped with a stirrer, a condenser, and a thermometer; add 0.072 g of an organic bismuth catalyst (DY-20), and heat to 45°C at a rate of 2°C / min. After the temperature is reached, continue the reaction for 2 h; add 0.675 g (0.0075 mol) of 1,4-butanediol (BDO); ​​heat to 65°C, and continue stirring and reacting for 2 h to obtain a polyurethane prepolymer.

[0040] (2) 6 g (0.006 mol) of monofunctional polyetheramine was added into the three-necked flask and reacted at 65° C. for 0.75 h to obtain a semi-blocked polyurethane resin.

[0041] (3) 1.004 g (0.009 mol) of hydroxyethyl acrylate (HEA) was added into the three-necked flask, and the temperature was raised to 80° C. and reacted for 3 h to obtain a UV-curable self-healing self-adhesive polyurethane resin having dual end-capping of the designed polyether and HEA.

[0042] The end-capping content of the polyetheramine prepared in Example 2 accounts for 40% of the molar number of the terminal groups of the entire elastic resin.

[0043] Example 3

[0044] UV curing self-repairing self-adhesive polyurethane resin, the preparation method thereof comprises the following steps:

[0045] (1) Add 20.16 g (0.12 mol) of hexamethylene diisocyanate (HDI) and 120 g (0.06 mol) of polytetramethylene ether glycol (PTMG) into a dry three-necked flask equipped with a stirrer, a condenser, and a thermometer; add 0.438 g of a catalyst, dimethylcyclohexylamine (DMCHA), and heat to 45°C at a rate of 2.5°C / min. After reaching the temperature, continue the reaction for 2 h; add 2.7 g (0.03 mol) of 1,4-butanediol (BDO); ​​heat to 65°C, and continue stirring and reacting for 2 h to obtain a polyurethane prepolymer.

[0046] (2) 18 g (0.018 mol) of monofunctional polyetheramine was added into the three-necked flask and reacted at 65° C. for 0.75 h to obtain a semi-blocked polyurethane resin.

[0047] (3) 4.872 g (0.042 mol) of hydroxyethyl acrylate (HEA) was added into the three-necked flask, and the temperature was raised to 85° C. and reacted for 2.5 h to obtain the designed PEA and HEA dual-terminated UV-curable self-healing self-adhesive polyurethane resin.

[0048] The end-capping content of the polyetheramine prepared in Example 3 accounts for 30% of the molar number of the terminal groups of the entire elastic resin.

[0049] Example 4

[0050] UV curing self-repairing self-adhesive polyurethane resin, the preparation method thereof comprises the following steps:

[0051] (1) 13.32 g (0.06 mol) of isophorone diisocyanate (IPDI) and 60 g (0.03 mol) of polytetramethylene glycol (PTMG) were added to a dry three-necked flask equipped with a stirrer, a condenser, and a thermometer; 0.073 g of catalyst dibutyltin dilaurate (DBTDL) was added, and the temperature was raised to 45°C at 3°C / min. After the temperature was reached, the reaction was continued for 2 h; 1.35 g (0.015 mol) of 1,4-butanediol (BDO) was added, the temperature was raised to 60°C, and the reaction was continued for 3 h to obtain a polyurethane prepolymer.

[0052] (2) 6 g (0.006 mol) of monofunctional polyetheramine was added into the three-necked flask and reacted at 60° C. for 1 h to obtain a semi-blocked polyurethane resin.

[0053] (3) 2.784 g (0.024 mol) of hydroxyethyl acrylate (HEA) was added into the three-necked flask, and the temperature was raised to 80° C. and reacted for 3 h to obtain a UV-curable self-healing self-adhesive polyurethane resin with dual end-capping of the designed polyether and HEA.

[0054] The end-capping content of the polyetheramine prepared in Example 4 accounts for 20% of the molar number of the terminal groups of the entire elastic resin.

[0055] Comparative Example 1

[0056] The photocurable polyurethane resin has a monofunctional polyetheramine content of 0%, a polyetheramine mass of 0 g, and a HEA mass of 3.48 g (0.03 mol). The resin is a pure HEA-terminated bifunctional photocurable polyurethane. Other preparation conditions and parameters are the same as those in Example 1 to obtain a photocurable polyurethane resin.

[0057] The tensile elongation at break of the obtained light-cured polyurethane resin is only 142%; and it has no bonding effect on the selected six substrates (wood, polyethylene terephthalate, polytetrafluoroethylene, tinplate, glass, and plastic).

[0058] Application Examples 1-4

[0059] Take 7g of the photocurable resin prepared in Example 1-4, add 1g of isobornyl acrylate (IBOA) and 2g of tetrahydrofurfuryl acrylate (THFA), stir evenly to prepare an adhesive, which is the adhesive of Application Example 1-4. The shear strength of the prepared adhesive on the PET film is tested according to GB / T 7124-2008 standard.

[0060] The test results of each embodiment are as follows:

[0061] (1) Mechanical properties test of photocurable resin

[0062] The mechanical properties of the light-cured polyurethane elastic resins prepared in Examples 1-4 were measured using a universal testing machine. Figure 1 As shown. Figure 1 It can be seen that with the increase of the PEA content used for end-capping, the elongation at break of the resin increases significantly, but the tensile strength also decreases accordingly. This is because with the increase of PEA content, the cross-linking density in the curing system is reduced, forming a looser network structure, making it easier for molecules to move, increasing flexibility, and thus improving elongation; at the same time, the PEA molecular chain itself contains ether bonds with high flexibility. With the continuous increase of PEA accession, the flexibility of the resin increases accordingly.

[0063] The adhesion performance of the resin prepared in Example 1 to different substrates was measured using a single lap tensile shear strength test method on a universal testing machine. Figure 2 and Figure 3As shown in the figure, it can be seen that the prepared resin has a certain viscosity to different substrates. Among them, the viscosity of glass is the largest, which can reach 398Kpa, followed by the shear strength of wood, which can reach 352Kpa.

[0064] (2) Self-healing performance test of photocurable resin

[0065] Polyetheramine end capping is connected to polyurethane to introduce dynamically reversible urea groups; the formed cross-linked structure is comb-shaped, and hydrogen bonds and urea groups can be enriched on the resin surface, thereby giving the resin certain self-healing properties.

[0066] like Figure 4 As shown: the light-cured polyurethane elastic resin strip prepared by the method described in Example 1 was cut in the middle, placed in a 60°C oven for 2 hours and then taken out. The strips were re-bonded together and had certain mechanical properties. This shows that the light-cured polyurethane elastic resin prepared by the present invention has excellent self-repairing properties.

[0067] (3) Adhesive performance test:

[0068] The shear strength of the adhesives prepared in Example 1-4 on polyethylene terephthalate (PET) was tested using the double lap tensile shear strength test method on a universal testing machine. Figure 5 As shown, the adhesives prepared with the four resins as base resins all have better bonding effects on PET, among which the resin prepared in Example 1 has the best effect.

[0069] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A UV curing self-repairing self-adhesive polyurethane resin, characterized in that: The preparation method of the UV-curable self-repairing self-adhesive polyurethane resin comprises the following steps: (1) Add diisocyanate and polyol into a reaction vessel, add a catalyst dropwise, heat the reaction until -NCO reaches the theoretical value, add 1,4-butanediol, heat to 60-70°C and react for 2-3 hours to obtain a polyurethane prepolymer; (2) adding polyetheramine to the polyurethane prepolymer prepared in step (1) to react and obtain a partially polyether-terminated polyurethane; (3) adding hydroxyethyl acrylate to the polyurethane prepared in step (2) for end-capping to obtain a UV-curable self-repairing self-adhesive polyurethane resin; The polyol is polytetramethylene ether diol with a molecular weight of 2000; The polyetheramine is a monofunctional polyetheramine with a molecular weight of 1000.

2. The UV curable self-repairing self-adhesive polyurethane resin according to claim 1, characterized in that: In step (1), the diisocyanate is isophorone diisocyanate or hexamethylene diisocyanate.

3. The UV curable self-repairing self-adhesive polyurethane resin according to claim 1, characterized in that: In step (1), the catalyst is one of dibutyltin dilaurate, an organic bismuth catalyst, and dimethylcyclohexylamine.

4. The UV curable self-repairing self-adhesive polyurethane resin according to claim 1, characterized in that: In step (1), the molar ratio of the diisocyanate to the polyol is 2:1; and the amount of the catalyst added is 0.09-0.32% of the total mass of the diisocyanate and the polyol.

5. The UV curable self-repairing self-adhesive polyurethane resin according to claim 1, characterized in that: In step (1), the temperature is raised to 40-50°C at a rate of 2-3°C / min and then reacted for 2-3h.

6. The UV curable self-repairing self-adhesive polyurethane resin according to claim 1, characterized in that: In step (1), the molar ratio of 1,4-butanediol to diisocyanate is 0.25:

1.

7. The UV curable self-repairing self-adhesive polyurethane resin according to claim 1, characterized in that: In step (2), the molar ratio of the polyetheramine to the diisocyanate is 0.1-0.5:1; the reaction temperature is 60-70°C, and the reaction time is 0.5-1h.

8. The UV curable self-repairing self-adhesive polyurethane resin according to claim 1, characterized in that: In step (3), the molar ratio of hydroxyethyl acrylate to diisocyanate is 0.1-0.5:1; the reaction temperature is 80-90°C, and the reaction time is 2-3h.

9. An application of the UV curable self-repairing self-adhesive polyurethane resin according to any one of claims 1 to 8, characterized in that: The UV curing self-repairing self-adhesive polyurethane resin is used to prepare a polyurethane adhesive; the polyurethane adhesive comprises the following components by mass percentage: 70% of the above UV curing self-repairing self-adhesive polyurethane resin; 10% of isobornyl acrylate and 20% of tetrahydrofurfuryl acrylate.

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