UV curing resin based on E-ACMO monomer and preparation method thereof

Abstract

The invention relates to the field of resin, in particular to UV curing resin based on an E-ACMO monomer and a preparation method of the UV curing resin based on the E-ACMO monomer, and the UV curing resin based on the E-ACMO monomer comprises the following raw materials in parts by weight: 50-70 parts of the E-ACMO monomer, 20-30 parts of bifunctional acrylate, 1-3 parts of a photoinitiator and 5-10 parts of nano clay. The finished product has high adhesive force, low shrinkage rate and excellent biocompatibility, the peel strength reaches 3.5-4.2 N / mm, the elongation at break is 20-50%, the hardness is 2B-3H, flexibility and rigidity are adjustable, the fluctuation of the adhesive force within the range of minus 30-120 DEG C is smaller than 10%, and the adhesive force is less than 10% within the range of minus 30-120 DEG C. The preparation method is suitable for scenes with strict requirements on safety and interface bonding force, such as medical catheter coatings, flexible electronic packaging and food-grade printing ink.

Description

Technical Field

[0001] The present invention relates to the field of resins, and in particular to a UV-curable resin based on an E-ACMO monomer and a preparation method thereof. Background Art

[0002] Resin generally refers to an organic polymer that softens or melts when heated, tends to flow under external force, and is solid, semi-solid, or sometimes liquid at room temperature. UV-curable resin based on ACMO monomers is a common example of this type of resin.

[0003] Existing UV-curable resins based on ACMO (acrylic morpholine) monomers typically suffer from the following issues: 1. Inadequate interfacial adhesion: The polar morpholine group has poor compatibility with hydrophobic substrates (such as polyethylene and silicone), resulting in peel strengths less than 1N / mm. 2. High brittleness: The homopolymer has an elongation at break of less than 10%, making it unable to adapt to the deformation of flexible substrates. 3. Limited biocompatibility: Unmodified ACMO has a Class III cytotoxicity rating (ISO 10993-5), limiting its application in medical devices. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides a UV-curable resin based on E-ACMO monomer, which can solve the problems existing in the background art. The present invention provides the following technical solutions: A UV-curable resin based on E-ACMO (ethoxylated ACMO) monomer comprises the following raw materials in parts by weight: 50-70 parts of E-ACMO monomer, 20-30 parts of difunctional acrylate, 1-3 parts of photoinitiator and 5-10 parts of nanoclay.

[0005] As a further embodiment of the present invention, the photoinitiator is TPO (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) or ITX (2-isopropylthioxanthone).

[0006] As a further embodiment of the present invention, the preparation method of the E-ACMO monomer is as follows: Under nitrogen protection, ACMO monomer and ethylene oxide are subjected to a ring-opening addition reaction at 60-80°C under Lewis acid catalysis, with the number of ethoxy repeating units (n=1-3) precisely controlled to obtain an intermediate. The intermediate is then capped with acetic anhydride for hydroxyl groups, followed by vacuum distillation and purification to obtain the E-ACMO monomer. The Lewis acid is boron trifluoride etherate complex. The acetic anhydride-capped hydroxyl groups are converted to acetate groups (-OCOCH3) at the terminal of the intermediate (HO-(CH2CH2O)n-ACMO, n=1-3) obtained by the ring-opening addition reaction to achieve end-protection of the hydroxyl groups. Acetic anhydride ((CH3CO)2O) undergoes a nucleophilic substitution reaction (acetylation) with an alcohol (R-OH) in the presence of a basic catalyst (such as pyridine or triethylamine) to produce the acetate (R-OCOCH3) and acetic acid (CH3COOH). The specific steps are as follows: 1. Under nitrogen protection, add the inert organic solvent tetrahydrofuran (THF), the organic base catalyst pyridine (pyridine), and 4-dimethylaminopyridine (DMAP) to the intermediate to react. 2. Add the acetylation reagent acetic anhydride (Ac2O) to carry out the acetylation reaction. 3. Slowly pour the reaction solution into a beaker filled with an ice-water mixture or a saturated aqueous sodium bicarbonate (NaHCO3) solution to quench the reaction. 4. Add a water-miscible organic solvent (such as ethyl acetate (EtOAc) or dichloromethane (DCM)) for extraction. Extraction is usually required two to three times, and all organic phases (containing the target product E-ACMO) are combined. 5. Wash the combined organic phases with water one to two times to remove water-soluble impurities, and then wash once with saturated brine (NaCl solution). 6. Add an anhydrous desiccant (such as anhydrous sodium sulfate (Na2SO4) or anhydrous magnesium sulfate (MgSO4)) to the organic phase for drying. 7. Concentration: Remove the solvent (DCM, THF, EtOAc, etc.) by distillation under reduced pressure on a rotary evaporator to obtain the crude product E-ACMO (acetylated product).

[0007] As a further embodiment of the present invention, the nanoclay is an organic modified montmorillonite, and the interlayer spacing of the nanoclay is not less than 2.5 nm. The preparation method of the organic modified montmorillonite comprises the following steps: 1. dispersing sodium montmorillonite in deionized water at 60-80°C to form a slurry with a mass fraction of 2-5%; 2. dissolving a long-chain quaternary ammonium salt cationic modifier (preferably dioctadecyldimethylammonium chloride) equivalent to 1.0-1.5 times the cation exchange capacity (CEC) of the montmorillonite in deionized water or a water / ethanol mixture at 60-80°C to prepare a 1-5wt% solution; 3. slowly adding the solution obtained in step (2) to the slurry of step (1) at 60-80°C with stirring, and continuing to heat and stir the reaction for 2-6 hours; 4. cooling and filtering after the reaction, and repeatedly washing the filter cake with hot deionized water at 60-80°C until no chloride ions are detected (AgNO3 solution detection); 5. Dry the washed filter cake in vacuum at 60-80° C. for 12-48 hours; 6. Grind and sieve to obtain powdered organic modified montmorillonite nanoclay with an interlayer spacing of not less than 2.5 nm.

[0008] As a further solution of the present invention: the difunctional acrylate is HDDA.

[0009] A method for preparing a UV-curable resin based on E-ACMO monomer comprises the following steps: (1) ball milling E-ACMO monomer, bifunctional acrylate, photoinitiator and nanoclay at 30-50 degrees Celsius until 90% of the particles have a size of no more than 100 nm to obtain a mixture; (2) The mixture is coated on a substrate and then cured using a UV light source to obtain a finished product.

[0010] As a further solution of the present invention: the UV light source is a 395nm UV-LED light source, and the curing energy is 400-600mJ / cm 2 , no nitrogen protection is required.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention introduces ethoxyl chains (EO chains) of controllable length into the ACMO monomer through precise ethoxylation of the molecular structure to construct a dynamic hydrogen bond network. The resulting finished product has high adhesion, low shrinkage, and excellent biocompatibility. The peel strength reaches 3.5-4.2N / mm, and it can directly bond to difficult-to-bond substrates such as silicone and PE, significantly improving adhesion. The elongation at break is 20-50%, and the hardness is 2B-3H, achieving adjustable flexibility and rigidity. The biocompatibility reaches medical grade, and UV curing efficiency can be maintained. It achieves both safety and performance, with good environmental adaptability. The adhesion fluctuation is less than 10% in the range of -30 to 120 degrees Celsius, making it suitable for extreme environments. The cytotoxicity rating is Class I (ISO 10993-5), which improves biosafety. It is suitable for scenarios with strict requirements on safety and interfacial bonding, such as medical catheter coatings, flexible electronic packaging, and food-grade printing inks. DETAILED DESCRIPTION

[0012] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0013] In this invention, the E-ACMO monomer provides dynamic hydrogen bonding, while the bifunctional acrylate regulates crosslink density. The ethoxylated segments connect to the morpholine ring via ether bonds, forming a reversible hydrogen-bonding network. This dynamic dissociation and recombination of hydrogen bonds occurs under external forces, simultaneously enhancing toughness and adhesion. The ethoxylated segments of the E-ACMO monomer create a hydrophobic-lipophilic synergistic effect with the hydrophobic substrate, increasing interfacial binding energy by 200%. Ethoxylation shields the inherent toxic groups of ACMO, increasing cell viability from 65% to over 95% using the MTT assay.

[0014] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0015] Example 1

[0016] Raw materials: 60 parts of E-ACMO monomer, 25 parts of HDDA, 2 parts of ITX and 8 parts of nanoclay, where n=2 in the E-ACMO monomer (the ethoxy chain length is 2 units).

[0017] Curing conditions: 395nm LED light source, energy 500mJ / cm 2 .

[0018] Comparative Example: Ordinary ACMO resin.

[0019] The finished product of Example 1 and the comparative example were subjected to performance tests, and the test results are shown in Table 1.

[0020] Table 1 Performance results index Example 1 Comparative Example Peel strength (PE substrate) 3.8N / mm 0.9N / mm Elongation at break (%) 38 9 Cell survival rate (%) 96 (Class I) 68 (Class III) Shore hardness 85D 90D 50um film curing speed (s) 2.5 3.0 As shown in Table 1, ethoxylated modified materials (such as E-ACMO) achieve synergistic optimization of safety and flexibility (cell viability 96% + elongation at break 38%) while maintaining high hardness (85D) and rapid curing. This breakthrough addresses the industry's pain point of "difficult bonding of high-hardness materials" (peel strength increased by 4.2 times). Applications include safety-sensitive applications such as medical device packaging, flexible electronic adhesives, and food-grade packaging coatings.

[0021] Example 2

[0022] The only difference from Example 1 is that natural bentonite is used instead of nanoclay. The prepared finished product can be used for printing ink for food packaging, and the migration amount is less than 0.01 mg / kg (GB 9685-2016).

[0023] The products of Example 1 and Example 2 were subjected to performance tests, and the test results are shown in Table 2 and Table 3.

[0024] Table 2 Key food safety data Test items Example 2 National standard limit Regularity Total migration (4% acetic acid, 40°C, 24h) 0.008 mg / kg ≤10 mg / kg þ Heavy metal migration (Pb / Cd / Cr, etc.) Not detected ≤0.01 mg / kg þ Volatile organic compounds (Toluene / Ethylbenzene, etc.) <0.001 mg / kg ≤0.5 mg / kg þ Table 3 Performance parameters Performance indicators Example 1 Example 2 Fluctuation range Peel strength (PE substrate) 3.8 N / mm 3.7N / mm -2.6% Elongation at break 38% 36% -5.3% 50μm curing speed 2.5s 2.6s +4 Shore hardness 85D 84D -1.2% Tables 2 and 3 show that the bonding, curing, and mechanical properties of the product in Example 2 do not differ significantly from those in Example 1, with fluctuations within the acceptable engineering range (±5%). Specifically, after replacing the nanoclay with natural bentonite, the migration amount of 0.008 mg / kg (measured value) meets food packaging requirements (<0.01 mg / kg). The performance of Example 2 is highly similar to that of Example 1 and can be directly used with food-grade inks (such as chocolate packaging and beverage label printing). Tetra Pak packages printed with the ink in Example 2 are certified under FDA 21 CFR §175.300 and EU EU10 / 2011.

[0025] This invention introduces ethoxy groups into ACMO for the first time and constructs a dynamic hydrogen bond network, overcoming the contradiction between adhesion and biosafety. The peel strength of this product reaches 3.8N / mm, reaching the level of structural adhesives and far exceeding the 1.5N / mm of existing UV adhesives. This enables the finished product of this invention to overcome the long-standing technical bottleneck of UV materials in the application of difficult-to-bond substrates and in the biomedical field. It has significant industrial value and market competitiveness, and can be extended from industrial adhesives to high-end medical and food contact applications, replacing silicone and epoxy resins.

[0026] It should be noted that, in the present invention, unless otherwise expressly specified or limited, the terms "fixed" and "disposed" should be understood in a broad sense. For example, they can refer to welded connections, bolted connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise expressly specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0027] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A UV curable resin based on E-ACMO monomer, characterized in that: The method comprises the following raw materials in parts by weight: 50-70 parts of E-ACMO monomer, 20-30 parts of bifunctional acrylate, 1-3 parts of photoinitiator and 5-10 parts of nano clay.

2. The UV curable resin based on E-ACMO monomer according to claim 1, characterized in that The photoinitiator is TPO or ITX.

3. The UV curable resin based on E-ACMO monomer according to claim 1 or 2, characterized in that The preparation method of the E-ACMO monomer is as follows: under nitrogen protection, ACMO monomer and ethylene oxide are subjected to ring-opening addition at 60-80 degrees Celsius and Lewis acid catalysis to obtain an intermediate, the intermediate is capped with hydroxyl groups by acetic anhydride, and then vacuum distillation and purification are performed to obtain the E-ACMO monomer.

4. The UV curable resin based on E-ACMO monomer according to claim 1, characterized in that The interlayer distance of the nanoclay is not less than 2.5 nm.

5. The UV curable resin based on E-ACMO monomer according to claim 1 or 4, characterized in that The difunctional acrylate is HDDA.

6. A method for preparing a UV-curable resin based on E-ACMO monomer, characterized in that: The following steps are involved: (1) ball milling E-ACMO monomer, bifunctional acrylate, photoinitiator and nanoclay at 30-50 degrees Celsius until 90% of the particles have a size of no more than 100 nm to obtain a mixture; (2) The mixture is coated on a substrate and then cured using a UV light source to obtain a finished product.

7. The method for preparing a UV-curable resin based on E-ACMO monomer according to claim 6, characterized in that: The UV light source is a 395nm UV-LED light source with a curing energy of 400-600mJ / cm 2 .