CN106866929A - A kind of polyfunctionality castor oil-base light-cured resin and its preparation method and application - Google Patents

Abstract

A multifunctional castor oil-based photocurable resin and its preparation method and application. The reaction raw materials are isocyanate and hydroxyacrylate, adding a polymerization inhibitor and a catalyst, and reacting under nitrogen protection for a certain period of time to obtain an intermediate isocyanate semi-blocked prepolymer. ; Castor oil is added to the isocyanate semi-blocked prepolymer prepared in the step to obtain castor oil-based polyurethane acrylate resin; the resin is mixed with photoinitiator and diluent, and under ultraviolet radiation, UV castor oil with excellent performance is obtained base resin. The photocurable resin synthesized by the present invention has higher molecular weight and viscosity, which strengthens the interaction between resin molecules and improves the photocrosslinking reaction efficiency of the resin; the product contains more terminal double bonds, can be quickly photocured, and is suitable for making UV curable coatings, 3D printing materials, etc.; the prepared photocurable resin has greatly improved the water absorption rate and volume shrinkage rate of the cured film, and at the same time has low cost, simple and controllable process, and the product is greener.

Description

A kind of multi-functionality castor oil-based photocurable resin and its preparation method and application

technical field

The invention belongs to the field of photocurable materials, and relates to a method for preparing a hydrophobic photocurable resin, in particular to a multifunctional vegetable oil-based photocurable resin and its preparation method and application.

Background technique

Ultraviolet (uv) curing technology is a new energy-saving and environmentally friendly technology. Due to its fast curing speed, environmental friendliness, low energy consumption, and no solvent volatilization, the application of light-curing products is becoming more and more extensive. At present, most photocurable resins rely on chemical reagents related to petroleum resources. At present, due to limited petrochemical resources and environmental protection issues, vegetable oil is cheap, abundant and biodegradable as a renewable resource. Therefore, researchers are turning more attention to the direction of vegetable oil-based photocurable materials.

Natural oils are a large class of natural organic compounds, defined as triglycerides of mixed fatty acids. The research mainly focuses on the chemical modification synthesis of unsaturated oils, and the introduction of some special functional groups (such as rigid groups, flame retardant elements) to meet the needs of material technology and performance. Castor oil is a non-edible oil that is widely sourced, inexpensive, and an environmentally friendly renewable resource. Its molecule contains natural hydroxyl groups and has a typical unsaturated fatty acid triglyceride structure. Castor oil is a viscous light yellow non-volatile non-drying oil, which contains three active functional groups of double bond, hydroxyl group and ester group, so it is easy to undergo a series of chemical reactions such as hydrolysis, saponification, amidation and oxidation, so that it can A chemically modified castor oil with various properties was obtained. Castor oil is mainly composed of ricinoleic acid, of which the content of ricinoleic acid (chemical name 12-hydroxy-9-octadecenoic acid) exceeds 89%, and the hydroxyl value is the highest among natural vegetable oils. The remaining fatty acids include linoleic acid (4.2%), oleic acid (3.0%), stearic acid (1%), palmitic acid (1%) and the like. Castor oil can also undergo alcoholysis with low-carbon polyols to obtain castor oil polyols with different hydroxyl functional numbers for alcoholysis and transesterification to obtain castor oil derivatives with different hydroxyl values and functionalities. These castor oil derivatives can be widely used as raw materials in coatings, inks and polyurethane industries.

In recent years, UV castor oil-based urethane acrylate (COPUA) has been prepared one after another. Liu Yaode uses dehydrated castor oil to prepare dry alkyd resin. The obtained alkyd resin has good drying speed, alkali resistance and flexibility. and other physical properties. Yeganeh synthesized a new type of polyurethane insulating coating with castor oil as raw material, and found that as the hydroxyl value of polyols decreased, the crosslinking density of polymers also decreased. Trevino uses castor oil and tert-butyl acetoacetate as raw materials to prepare castor oil β-ketoester, which is then assimilated with a multifunctional amine crosslinking agent to obtain a coating film with good brightness and flexibility. Shi Wenfang and others reacted diisocyanate and diethanolamine to prepare hyperbranched polyurethane, and then modified hyperbranched polyurethane with self-made diisocyanate-hydroxyethyl acrylate monomer to prepare hyperbranched polyurethane acrylate.

Contents of the invention

The technical problem that solves:: the purpose of the present invention aims at developing new varieties of UV resins, overcomes the shortcomings of current UV resins such as dependence on petrochemical raw materials and low hydrophobicity, and provides a kind of multifunctionality castor oil-based photocurable resin and its preparation method And application, thereby improving the photocrosslinking reaction efficiency of photocurable resin, has the advantages of stable product quality and low cost.

Technical solution: a method for preparing a multifunctional castor oil-based photocurable resin, comprising the following steps: (1) using isocyanate and hydroxyacrylate as raw materials, adding an effective amount of catalyst and polymerization inhibitor, nitrogen protection, at 20 At -120°C, until the NCO content reaches the expected value of 14%~7%, the isocyanate semi-blocked intermediate is obtained, wherein the molar ratio of isocyanate to hydroxyacrylate is 0.5-1.44:1, and the reaction time is 2-10 hours ; The polymerization inhibitor is selected from any one of p-methoxyphenol, p-hydroxyanisole, hydroquinone, and the polymerization inhibitor consumption is 0.5-4% of the total weight of the reaction material; the catalyst is selected from Any one of dibutyltin dilaurate, stannous octoate, and dimethylethanolamine, the catalyst dosage is 1-5% of the total weight of the reaction material; (2) the isocyanate semi-blocked intermediate obtained in step (1) React with castor oil, the molar ratio is 0.6-0.8:1, the temperature is 30-140 ° C, the reaction time is 3-12 hours, until the NCO content is less than 0.5%, to obtain polyurethane acrylate prepolymer; (3) polyurethane Acrylate prepolymer, photoinitiator accounting for 1%-5% of the total mass of the reactants and diluent accounting for no more than 40% of the total mass of the reactants are mixed, thoroughly stirred and ultrasonically dispersed, cast or coated, and UV light is used to obtain more Functional castor oil based light curable resin.

The isocyanate described in step (1) is a compound containing two isocyanate groups (-NCO) or a mixture thereof, and the compound is isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), diphenylmethane Any of diisocyanate (MDI), p-phenylene diisocyanate (PPDI), cyclohexane dimethylene diisocyanate (HXDI), norbornane diisocyanate (NBDI).

The hydroxy acrylate in step (1) is pentaerythritol triacrylate, dipentaerythritol pentaacrylate or trimethylolpropane diacrylate.

The raw materials in the step (1) are reacted in a solvent selected from n-hexane, butanone or cyclohexane, and the solvent is removed by rotary evaporation at the end of the step (2).

The molar ratio of the isocyanate semi-blocked intermediate to castor oil in step (2) is 0.6:1.

The diluent in step (3) is at least one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, pentaerythritol triacrylate, triethylene glycol diacrylate, and propane trimethylol triacrylate. A sort of.

The photoinitiator in the step (3) is 2-hydroxy-2-methylpropiophenone, and the dosage accounts for 2% of the total mass of reactants.

The mass ratio of the polyurethane acrylate prepolymer, photoinitiator and diluent in step (3) is 0.78:0.02:0.2.

The multifunctional castor oil-based photocurable resin prepared by the above method.

Application of the above multifunctional castor oil-based photocurable resin in the preparation of coatings, inks or 3D printing materials.

Beneficial effects: the multifunctional castor oil-based photocurable resin synthesized by the invention belongs to a new variety, and can be quickly cross-linked and cured. The synthesized COPUA resin introduces a rigid structure and acrylate groups, the curing efficiency is greatly improved, and after curing, it has good hydrophobicity and thermal stability, and the comprehensive performance is improved. The synthesis reaction process is simple, easy to control, does not require the use of special equipment, and the raw materials are renewable and partially degradable, meeting the requirements of energy saving and environmental protection, and have broad application prospects.

Description of drawings

Figure 1 is the FT-IR spectrum of COPUA;

Fig. 2 is the ¹ H-NMR spectrum of COPUA;

Figure 3 is the contact angle diagram of COPUA.

detailed description

Further description will be given below with specific examples.

Example 1

(1) In the presence of the solvent n-hexane, using isocyanate and pentaerythritol triacrylate as raw materials (the molar ratio of isocyanate and acrylate is 0.8:1), add catalyst dibutyltin dilaurate (the total mass of reactants 2%) and the polymerization inhibitor p-hydroxyanisole (1% of the total mass of the reactants), under the protection of nitrogen, react at 30°C for 4 hours until the NCO content reaches 7%, and the isocyanate semi-blocked intermediate is obtained;

(2) React the semi-blocked isocyanate intermediate obtained in step (1) with castor oil (the molar ratio of materials is 0.9:1), the temperature is 40°C, and the reaction time is 10 hours until the NCO content is lower than 0.5%, to obtain polyurethane Acrylate prepolymer, solvent removed by rotary evaporation.

(3) Mix the urethane acrylate prepolymer with the photoinitiator 2-hydroxy-2-methylpropiophenone and the diluent hydroxyethyl acrylate in a ratio of 78%: 2%: 20% by mass fraction, stir thoroughly and ultrasonically Disperse for 30 minutes, pour or coat, and UV light to obtain COPUA cured splines. Figure 1 is the FT-IR spectrum of COPUA; Figure 2 is the ¹ H-NMR spectrum of COPUA; Figure 3-a is the contact angle of COPUA is 105.16°;

Example 2

(1) In the absence of solvent, using isocyanate and pentaerythritol triacrylate as raw materials (the molar ratio of isocyanate and acrylate is 0.9:1), add catalyst dibutyltin dilaurate (2% of the total mass of reactants %) and polymerization inhibitor p-methoxyphenol (1.5% of the total mass of the reactants), under nitrogen protection, react at 20°C for 5 hours until the NCO content reaches 6.5%, and the isocyanate semi-blocked intermediate is obtained;

(2) React the semi-blocked isocyanate intermediate obtained in step (1) with castor oil (the molar ratio of materials is 0.9:1), the temperature is 50°C, and the reaction time is 8 hours until the NCO content is lower than 0.5%, to obtain polyurethane Acrylate prepolymer;

(3) Mix the urethane acrylate prepolymer with the photoinitiator 2-hydroxy-2-methylpropiophenone and the diluent hydroxyethyl methacrylate at a mass fraction of 83%: 2%: 15%, and stir thoroughly After ultrasonic dispersion for 30 minutes, cast into a film, and UV irradiate to obtain COPUA cured splines, and the post-heat curing condition is 120°C for 2 hours. Figure 3-b shows that the contact angle of COPUA is 95.74°.

Example 3

(1) Under the condition of n-butyl ketone as solvent, isocyanate and pentaerythritol triacrylate are used as raw materials (the molar ratio of isocyanate and acrylate is 0.7:1), and the catalyst dibutyltin dilaurate (total mass of reactants 3%) and the polymerization inhibitor hydroquinone (2% of the total mass of the reactants), under the protection of nitrogen, react at 20°C for about 7 hours until the NCO content reaches 7.8%, and the isocyanate semi-blocked intermediate is obtained;

(2) React the semi-blocked isocyanate intermediate obtained in step (1) with castor oil (the molar ratio of materials is 0.9:1), the temperature is 40°C, and the reaction time is 5 hours, until the NCO content is lower than 0.5%, and polyurethane is obtained Acrylate prepolymer;

(3) Mix the urethane acrylate prepolymer with the photoinitiator 2-hydroxy-2-methylpropiophenone and the diluent triethylene glycol diacrylate at a mass fraction of 78%: 2%: 20% , fully stirred and ultrasonically dispersed for 40 minutes, poured into a film, and UV irradiated to obtain a COPUA cured sample. The post-heat curing condition was 120°C for 1 hour. Figure 3-c shows that the contact angle of COPUA is 112.15°

Example 4

(1) Under the condition of cyclohexane as the solvent, using isocyanate and pentaerythritol triacrylate as raw materials (the molar ratio of isocyanate and acrylate is 0.7:1), add catalyst dibutyltin dilaurate (total mass of reactants 3%) and the polymerization inhibitor hydroquinone (1% of the total mass of the reactants), under nitrogen protection, react at 50°C for about 4 hours until the NCO content reaches 7.5%, and the isocyanate semi-blocked intermediate is obtained;

(2) React the semi-blocked isocyanate intermediate obtained in step (1) with castor oil (the molar ratio of materials is 1:1.1), the temperature is 80°C, and the reaction time is 5 hours until the NCO content is lower than 0.5%, to obtain polyurethane Acrylate prepolymer, solvent removed by rotary evaporation.

(3) Mix the urethane acrylate prepolymer with the photoinitiator 2-hydroxy-2-methylpropiophenone and the diluent propane trimethylol triacrylate according to the mass fraction of 78%: 2%: 20%, and stir well After ultrasonic dispersion for 30 minutes, cast to form a film, and UV light to obtain COPUA cured splines, the post-heat curing condition is 120°C for 1 hour. Figure 3-d shows that the contact angle of COPUA is 109.81°

Example 5

(1) Under solvent-free conditions, using isocyanate and pentaerythritol triacrylate as raw materials (the molar ratio of isocyanate and acrylate is 1.2:1), add catalyst dibutyltin dilaurate (2% of the total mass of reactants ) and the polymerization inhibitor hydroquinone (0.5% of the total mass of the reactants), under the protection of nitrogen, react at 80°C for about 2 hours until the NCO content reaches 8%, and the isocyanate semi-blocked intermediate is obtained;

(2) React the semi-blocked isocyanate intermediate obtained in step (1) with castor oil (the molar ratio of materials is 1:1.2), the temperature is 70°C, and the reaction time is 7 hours until the NCO content is lower than 0.5%, to obtain polyurethane Acrylate prepolymer;

(3) Mix the urethane acrylate prepolymer with the photoinitiator 2-hydroxy-2-methylpropiophenone and the diluent hydroxyethyl acrylate in a ratio of 68%: 2%: 30% by mass fraction, stir thoroughly and ultrasonically Disperse for 40 minutes, cast to form a film, and UV light to obtain a COPUA cured sample. Figure 3-e shows that the contact angle of COPUA is 118.36°

The present invention is not limited to the above-mentioned embodiments, and all of the contents of the present invention can be implemented and have the above-mentioned good effects.

Claims (10)

1. a kind of preparation method of polyfunctionality castor oil-base light-cured resin, it is characterised in that comprise the following steps:

（1）With isocyanates and hydroxy acrylate as raw material, the catalyst and polymerization inhibitor of effective dose are added, lead to nitrogen protection, Under the conditions of 20-120 DEG C, until NCO content reaches desired value 14% ~ 7%, obtain isocyanates and partly block intermediate, wherein different The molar ratio of material of cyanate and hydroxy acrylate is 0.5-1.44:1, the reaction time is 2-10 hours；The polymerization inhibitor choosing Any one from p methoxy phenol, MEHQ, hydroquinones, polymerization inhibitor consumption is reaction mass gross weight 0.5-4%；The catalyst is selected from any one in dibutyltin dilaurate, stannous octoate, dimethylethanolamine, catalysis Agent consumption is the 1-5% of reaction mass gross weight；

（2）By step（1）The isocyanates for obtaining half blocks intermediate and is reacted with castor oil, and mol ratio is 0.6-0.8:1, temperature It it is 30-140 DEG C, the reaction time is 3-12 hours, until NCO content is less than 0.5%, obtains polyurethane acrylate prepolymer；

（3）By polyurethane acrylate prepolymer, account for the light trigger of reactant gross mass 1%-5% and account for reactant gross mass not Diluent mixing more than 40%, is sufficiently stirred for rear ultrasonic disperse, cast or film, and UV illumination obtains polyfunctionality castor oil-base Light-cured resin.

2. preparation method according to claim 1, it is characterised in that the isocyanates described in step (1) is different containing two The compound of cyanate group (- NCO) or its mixture, the compound are IPDI（IPDI）, first Phenylene diisocyanate（TDI）, methyl diphenylene diisocyanate（MDI）, PPDI（PPDI）, the methylene of hexamethylene two Group diisocyanate（HXDI）, norbornene alkyl diisocyanate（NBDI）In any one.

3. preparation method according to claim 1, it is characterised in that step（1）Described hydroxy acrylate is Ji Wusi Alcohol triacrylate, Dipentaerythritol Pentaacrylate or trimethylolpropane diacrylate.

4. preparation method according to claim 1, it is characterised in that step（1）Described raw material is to react in a solvent, The solvent is selected from n-hexane, butanone or hexamethylene, and in step（2）Solvent is removed finally by rotary evaporation.

5. preparation method according to claim 1, it is characterised in that step（2）The isocyanates half block intermediate with The molar ratio of material of castor oil is 0.6:1.

6. preparation method according to claim 1, it is characterised in that step（3）The diluent be hydroxy-ethyl acrylate, Hydroxyethyl methacrylate, hydroxy-ethyl acrylate, pentaerythritol triacrylate, triethylene-glycol diacrylate, 3 third At least one in olefin(e) acid propane front three alcohol ester.

7. preparation method according to claim 1, it is characterised in that step（3）The light trigger is 2- hydroxyl -2- first Base propiophenone, consumption accounts for the 2% of reactant gross mass.

8. preparation method according to claim 1, it is characterised in that step（3）The polyurethane acrylate prepolymer, The mass ratio of light trigger and diluent is 0.78:0.02:0.2.

9. the polyfunctionality castor oil-base light-cured resin that any methods described of claim 1 ~ 8 is prepared.

10. the polyfunctionality castor oil-base light-cured resin described in claim 9 is in coating, ink or 3D printing material is prepared Application.