Photosensitive Resin, Photocuring Material Based on Biobased Polyol PO3G and Preparation Method Thereof

Abstract

The present invention discloses a photosensitive resin, a photocuring material and their preparation based on bio-based polyol PO3G. The photosensitive resin comprises the following components in weight percentage: 55-75% of polyurethane acrylate prepolymer, 1-3% of photoinitiator, 10-30% of active diluent, and 10-15% of chain extender. The polyurethane acrylate prepolymer is prepared by the following method: first, bio-based polyol PO3G is subjected to a condensation reaction with isocyanate under the action of a catalyst to obtain polyurethane; then, a capping agent is added to the polyurethane for a capping reaction to obtain the product. The photosensitive resin prepared by the present invention using bio-based polyol PO3G has both low viscosity, high strength and high toughness; and the bio-based polyol used therein is 100% renewable polytrimethylene ether glycol, which is a degradable material and is more environmentally friendly.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a photosensitive resin, a photocuring material based on bio-based polyol PO3G, and a preparation method thereof. The photocuring material can be applied to the field of 3D printing. Background Art

[0002] The photocuring 3D printing technology has unique advantages. Usually, an ultraviolet light source is used to irradiate a liquid photosensitive resin at room temperature to cure and crosslink it into a three-dimensional model. The obtained products have high precision, fast photocuring speed, low working temperature, and are energy-saving and environmentally friendly. Due to the instantaneous photocuring characteristics, the photosensitive resin has become the raw material for photocuring 3D printing. Its composition mainly includes several components, namely, a photoinitiator, an oligomer, an active diluent, and other additives. The photocuring principle is that the photoinitiator absorbs the energy of a light source with a specific wavelength and then decomposes into active intermediates, which carry out a photopolymerization reaction with the oligomer and diluent containing unsaturated groups (such as double bonds), causing the molecular chains to crosslink to form a photocuring material.

[0003] As the main component of the photosensitive resin, the oligomer plays a crucial role in the mechanical properties of the photocuring material. Commonly used oligomers include epoxy acrylate, polyurethane acrylate, polyester acrylate, and polyether acrylate. Polyester acrylate is generally obtained by the esterification reaction of acrylic acid and unsaturated polyester. During the photocuring reaction, the curing rate is often slow, and the corresponding product has low hardness and poor mechanical strength. Polyether acrylate has a low viscosity, and the material has good flexibility, but the tensile strength and hardness are poor, and the chemical resistance is not good. Considering factors such as mechanical strength and curing speed, epoxy acrylate and polyurethane acrylate are the most widely used.

[0004] An excellent 3D printing photosensitive resin should have characteristics such as low viscosity, high strength, and good toughness. However, most photocuring 3D printing materials are difficult to meet the above requirements simultaneously. The viscosity of the photosensitive resin has a great influence on the fluidity of the resin during the printing process. Too high viscosity will result in low printing accuracy and poor mechanical properties of the 3D printed product. Currently, domestic photocuring 3D printing photosensitive resins usually have a relatively high viscosity and insufficient toughness. Among them, the widely used epoxy acrylate is prone to form a relatively high crosslinking density during the photocuring process, resulting in high viscosity, large internal stress, overly brittle properties, poor flexibility, and a small adjustable range of mechanical properties of the material. Therefore, to solve the contradiction between the viscosity and properties of the photosensitive resin, developing a photosensitive resin with both low viscosity, high strength, and high toughness is the key to the development of photocuring 3D printing. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a photosensitive resin, a photocuring material based on bio-based polyol PO3G, and a preparation thereof.

[0006] The object of the present invention is achieved by the following technical solutions:

[0007] In a first aspect, the present invention provides a photosensitive resin based on bio-based polyol PO3G, comprising the following raw material components in weight percentage:

[0008] Polyurethane acrylate prepolymer 55 - 75%,

[0009] Photoinitiator 1 - 3%,

[0010] Reactive diluent 10 - 30%,

[0011] Chain extender 10 - 15%;

[0012] Wherein, the polyurethane acrylate prepolymer is prepared by the following method:

[0013] First, bio-based polyol PO3G (bio-based polytrimethylene ether glycol) is subjected to a condensation reaction with isocyanate under the action of a catalyst to obtain polyurethane; then a capping agent is added to the polyurethane for a capping reaction to obtain the product.

[0014] As a preferred solution, the number average molecular weight of the bio-based polyol PO3G is 250 - 2000. More preferably, the number average molecular weight of the bio-based polyol PO3G is 650 - 1000.

[0015] As a preferred solution, the isocyanate is one or more of hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexane diisocyanate (TMDI), 1,3-dimethylisocyanate cyclohexane (H6XDI), m-xylene diisocyanate (XDI), 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), isophorone diisocyanate (IPDI), 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-dicyclohexylmethane diisocyanate (H 12 MDI) and p-phenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI).

[0016] More preferably, the isocyanate is 1,3-dimethylisocyanate cyclohexane (H6XDI), isophorone diisocyanate (IPDI), m-xylene diisocyanate (XDI).

[0017] As a preferred solution, the catalyst is one or more of stannous octoate, dibutyltin dilaurate, zinc isooctoate (naphthenate).

[0018] As a preferred embodiment, the capping agent includes one or more of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, tert-butylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, caprolactam, N-methylacetamide, succinimide, acetanilide, N-isopropylmethacrylamide, N-methylmethacrylamide, N-methylaniline, diphenylamine, N-phenylnaphthalene, 2,2,6,6-tetramethylpiperidine, diisopropylamine, and dibutylamine.

[0019] As a preferred embodiment, the reaction temperature of the polymerization reaction is 60-75 °C, and the reaction time is 4-6 h.

[0020] As a preferred embodiment, the reaction temperature of the capping reaction is 45-55 °C, and the reaction time is 1-2 h.

[0021] As a preferred embodiment, the molar ratio of the bio-based polytetramethylene ether glycol to the isocyanate is 1:2.

[0022] As a preferred embodiment, the addition amount of the catalyst is 0.1-0.3% of the weight of the bio-based polytetramethylene ether glycol.

[0023] As a preferred embodiment, the addition amount of the capping agent is 30-60% of the weight of the polyurethane.

[0024] As a preferred embodiment, the photoinitiator includes one or more of 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0025] As a preferred embodiment, the reactive diluent includes one or more of monofunctional hydroxyethyl acrylate, isobornyl acrylate, and isobornyl methacrylate; difunctional 1,6-hexanediol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, and tetrapropylene glycol diacrylate; and polyfunctional trimethylolpropane triacrylate, pentaerythritol triacrylate, and pentaerythritol tetraacrylate.

[0026] As a preferred solution, the chain extender includes one or more of ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, 1,4-cyclohexanediol, ethylenediamine, propylenediamine, 1,5-pentanediamine, 2-methyl-1,5-pentanediamine, 1,6-hexanediamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-diaminodiphenylmethane. More preferably, the chain extender is 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane. The use of an amine chain extender to react with polyurethane to form urea bonds, whose bond energy is stronger than the urethane bonds formed by an alcohol chain extender and polyurethane, results in a higher strength of the photocurable material. Moreover, the molecular structures of these two more preferred chain extenders are rigid structures containing benzene rings or cyclohexanes. Compared with chain extenders such as 1,5-pentanediamine with aliphatic chains, they have stronger polarity and increased intermolecular forces, which is conducive to further improving the tensile strength of the material.

[0027] In a second aspect, the present invention also provides a method for preparing a photosensitive resin based on the aforementioned bio-based polyol PO3G, comprising the following steps: thoroughly mixing and stirring a polyurethane acrylate prepolymer with a photoinitiator, an active diluent, and a chain extender, and removing air bubbles under vacuum conditions to obtain the photosensitive resin.

[0028] In a third aspect, the present invention also provides a photocurable material prepared from the aforementioned photosensitive resin based on bio-based polyol PO3G.

[0029] In a fourth aspect, the present invention also provides a method for preparing the aforementioned photocurable material, comprising the following steps: subjecting the photosensitive resin based on bio-based polyol PO3G to a photocuring reaction under ultraviolet light irradiation, and then performing a thermal curing reaction to obtain the photocurable material.

[0030] Among them, the ultraviolet light used in the photocuring reaction has a wavelength of 365 nm and an irradiation time of 0.5 - 1.5 h.

[0031] The thermal curing reaction is carried out at a curing temperature of 100 - 120 °C and a curing time of 12 h.

[0032] Through the thermal curing reaction, the blocking agent breaks at high temperature, releasing the isocyanate groups in the polyurethane to react with the chain extender, and finally obtaining a photocurable material based on bio-based polyol PO3G, which can be applied to the field of 3D printing.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1) The photosensitive resin prepared by the present invention using bio-based polyol PO3G has both low viscosity, high strength and high toughness; and the bio-based polyol used is 100% renewable polytrimethylene ether glycol, which is a degradable material and is more environmentally friendly.

[0035] 2) The present invention further sequentially performs photocuring and thermal curing on the photosensitive resin, which can further improve the mechanical strength of the obtained photocured material. Description of the Drawings

[0036] By reading the following detailed description of the non-limiting embodiments with reference to the accompanying drawings, other features, objects and advantages of the present invention will become more apparent:

[0037] Figure 1 It is the Fourier transform infrared spectrum diagram of Example 1 of the present invention. H6XDI represents cyclohexane 1,3-dimethylisocyanate, H6XDI-PUA represents a polyurethane acrylate prepolymer formed with cyclohexane 1,3-dimethylisocyanate as the hard segment, and Cured-PUA represents the photocured material after ultraviolet photocuring reaction;

[0038] Figure 2 It is the tensile stress-strain curve of the photocured material based on bio-based polyol PO3G prepared in Example 1 of the present invention. Detailed Embodiments

[0039] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several modifications and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0040] The polyurethane acrylate structure consists of two parts: polyurethane and acrylate. Among them, polyurethane is a polymer formed by the reaction of isocyanate and oligomeric polyol. Isocyanate serves as the hard segment, and oligomeric polyol serves as the soft segment. Due to the thermodynamic incompatibility between the hard segment and the soft segment, polyurethane is endowed with a unique microphase separation structure, which enables great controllability of various properties of the material such as tensile strength and flexibility, and can realize the transformation from elastomer to hard material. Due to the introduction of the polyurethane part, the excellent properties of polyurethane can be imparted to this type of photosensitive resin, such as high wear resistance, high strength and good toughness.

[0041] In polyurethane acrylate, polyols serve as the soft segments for preparing polyurethanes and are synthesized from non-renewable fossil fuel resources. In recent years, researchers have begun to seek polyols prepared from renewable raw materials to meet the requirements of sustainable development. An ideal polyether diol should possess characteristics such as low melting point, low viscosity, and slow crystallization rate. DuPont has prepared 100% renewable polytrimethylene ether glycol (PO3G) through corn fermentation, which can meet the above characteristics simultaneously. Compared with the structure of common polyols with an even number of carbon atoms in the main chain, the repeating unit of the main chain of bio-based PO3G has a rare odd number of carbon atoms, and the main chain has more C-O-C bonds, resulting in better flexibility. Through preliminary experiments, it has been found in this invention that it can form a polyurethane structure with a greater degree of microphase separation with isocyanates, endowing the material with excellent comprehensive properties. Based on this, this invention has prepared a photosensitive resin and a photocuring material with low viscosity, bio-based, high strength, and high toughness by using bio-based polyol PO3G, which can be widely used in the field of 3D printing.

[0042] Meanwhile, in this invention, a dual curing method of light and heat is also adopted. The blocking agent used can break at high temperature, and the re-released isocyanate groups react with the chain extender, causing the polyurethane to chain-extend again, thereby further enhancing the mechanical strength of the photocuring material.

[0043] The technical solutions of this invention will be further described below in conjunction with specific embodiments.

[0044] In the following embodiments, bio-based polytrimethylene ether glycols (PO3G) with different number-average molecular weights were all purchased from DuPont.

[0045] Example 1

[0046] This example provides a preparation method of a photocuring material based on bio-based polyol PO3G, including the following steps:

[0047] Step 1: Pre-dehydrate 100 g of bio-based polytrimethylene ether glycol (PO3G) with a molecular weight of 1000 at 110 °C under vacuum for 2 h. Add 0.1 g of catalyst stannous octoate and 39.6 g of 1,3-dimethylcyclohexyl isocyanate into a three-necked flask equipped with a thermometer and an electric stirrer. Under a nitrogen atmosphere, react PO3G with 1,3-dimethylcyclohexyl isocyanate at 60 °C for 5 h, and synthesize polyurethane by the condensation polymerization method.

[0048] Step 2: Add 38.2 g of blocking agent tert-butylaminoethyl methacrylate at 50 °C, and carry out a blocking reaction on the polyurethane prepared in Step 1 for 1 h to obtain a polyurethane acrylate prepolymer.

[0049] Step 3: At room temperature, add 59 wt% of the polyurethane acrylate prepolymer synthesized in step 2, 1 wt% of the photoinitiator 1-hydroxycyclohexyl phenyl ketone, 30 wt% of the active diluent isobornyl acrylate, and 10 wt% of the chain extender 4,4'-diaminodiphenylmethane into a round-bottom flask, mix and stir thoroughly, and remove bubbles under vacuum to obtain a photosensitive resin based on bio-based polyol PO3G.

[0050] Step 4: Expose the photosensitive resin based on bio-based polyol PO3G under ultraviolet light for 1 hour to perform a photocuring reaction of the photosensitive resin. Then perform a secondary thermal curing at 120°C to break the end-capping agent at high temperature, release the isocyanate group to react with the chain extender, and finally prepare a photocurable material based on bio-based polyol PO3G.

[0051] like Figure 1 As shown, 2270cm -1 is the stretching vibration peak of the isocyanate group. After 1,3-dimethylisocyanate cyclohexane reacts with bio-based polyol PO3G and a capping agent to generate polyurethane acrylate (H6XDI-PUA), the characteristic peak of the isocyanate group disappears and the characteristic peak of the urethane group of the polyurethane appears. -1 is the stretching vibration peak of NH, 1715cm -1 is the stretching vibration peak of the carbonyl group. After the photocuring reaction, it is located at 810cm -1 The C=C characteristic peak of the acrylate group disappeared, indicating that the double bond was successfully polymerized under ultraviolet light, and the photocurable material (Cured-PUA) based on the bio-based polyol PO3G was successfully generated.

[0052] The tensile stress-strain curve of the photocurable material prepared in this example is shown in Figure 2 As shown, the results show that the prepared photocurable material can still achieve an elongation at break of >400% while maintaining a high tensile strength of 35.2MPa. Among them, the bio-based polyol PO3G shows excellent flexibility during the stretching process, and when the molecular chain is stretched to a certain extent, oriented crystallization will occur, thereby achieving the purpose of both tensile strength and toughness.

[0053] Example 2

[0054] This embodiment provides a method for preparing a photocurable material based on bio-based polyol PO3G, comprising the following steps:

[0055] Step 1: Pre-dehydrate 100 g of bio-based polytrimethylene ether glycol (PO3G) with a molecular weight of 1000 at 110 °C under vacuum for 2 h. Add 0.1 g of catalyst stannous octoate and 22.2 g of isophorone diisocyanate into a three-necked flask equipped with a thermometer and an electric stirrer. Under a nitrogen atmosphere, react PO3G with isophorone diisocyanate at 65 °C for 4 h, and synthesize polyurethane by the condensation polymerization method.

[0056] Step 2: Add 38.2 g of blocking agent tert-butylaminoethyl methacrylate at 50 °C, and carry out a blocking reaction on the polyurethane prepared in Step 1 for 2 h to obtain a polyurethane acrylate prepolymer.

[0057] Step 3: At room temperature, add 55 wt% of the polyurethane acrylate prepolymer synthesized in Step 2, 1.5 wt% of photoinitiator 2-hydroxy-2-methyl-1-phenylpropanone, 30 wt% of reactive diluent isobornyl methacrylate, and 13.5 wt% of chain extender 4,4'-diaminodicyclohexylmethane into a round-bottom flask, mix and stir well, and remove air bubbles under vacuum conditions to obtain a photosensitive resin based on bio-based polyol PO3G.

[0058] Step 4: Irradiate the photosensitive resin based on bio-based polyol PO3G with ultraviolet light for 1 h to carry out the photocuring reaction of the photosensitive resin. Then carry out secondary thermal curing at 120 °C to break the blocking agent at high temperature, release the isocyanate group to react with the chain extender, and finally prepare a photocured material based on bio-based polyol PO3G.

[0059] Example 3

[0060] This example provides a preparation method of a photocured material based on bio-based polyol PO3G, including the following steps:

[0061] Step 1: Pre-dehydrate 100 g of bio-based polytrimethylene ether glycol (PO3G) with a molecular weight of 650 at 110 °C under vacuum for 2 h. Add 0.1 g of catalyst dibutyltin dilaurate and 61.0 g of 1,3-dimethylcyclohexyl isocyanate into a three-necked flask equipped with a thermometer and an electric stirrer. Under a nitrogen atmosphere, react PO3G with 1,3-dimethylcyclohexyl isocyanate at 60 °C for 6 h, and synthesize polyurethane by the condensation polymerization method.

[0062] Step 2: Add 58.7 g of blocking agent tert-butylaminoethyl methacrylate at 55 °C, and carry out a blocking reaction on the polyurethane prepared in Step 1 for 1 h to obtain a polyurethane acrylate prepolymer.

[0063] Step 3: At room temperature, add 63 wt% of the polyurethane acrylate prepolymer synthesized in Step 2, 2 wt% of the photoinitiator 1-hydroxycyclohexyl phenyl ketone, 20 wt% of the active diluent ethylene glycol dimethacrylate, and 15 wt% of the chain extender 3,3'-dimethyl-4,4'-diaminodicyclohexyl methane into a round-bottom flask, mix and stir well, and remove the bubbles under vacuum to obtain a photosensitive resin based on the bio-based polyol PO3G.

[0064] Step 4: Irradiate the photosensitive resin based on the bio-based polyol PO3G with ultraviolet light for 1 h to carry out the photocuring reaction of the photosensitive resin. Then, perform secondary thermal curing at 120 °C to break the capping agent at high temperature, release the isocyanate group to react with the chain extender, and finally prepare a photocured material based on the bio-based polyol PO3G.

[0065] Example 4

[0066] This example provides a preparation method of a photocured material based on the bio-based polyol PO3G. The preparation steps are basically the same as those in Example 1, except that: in Step 1, the bio-based polytriethylene glycol used has a molecular weight of 2000.

[0067] Example 5

[0068] This example provides a preparation method of a photocured material based on the bio-based polyol PO3G. The preparation steps are basically the same as those in Example 1, except that: in Step 1, the bio-based polytriethylene glycol used has a molecular weight of 250.

[0069] Example 6 (The chain extender is 1,5-pentanediamine, and its performance is compared with that of the preferred chain extender.)

[0070] This example provides a preparation method of a photocured material based on the bio-based polyol PO3G, including the following steps:

[0071] Step 1: Pre-dehydrate 100 g of the bio-based polytriethylene glycol (PO3G) with a molecular weight of 1000 at 110 °C under vacuum for 2 h. Add 0.2 g of the catalyst stannous octoate and 39.6 g of 1,3-dimethylisocyanatocyclohexane into a three-necked flask equipped with a thermometer and an electric stirrer. Under a nitrogen atmosphere, react PO3G with 1,3-dimethylisocyanatocyclohexane at 60 °C for 5 h, and synthesize polyurethane by the condensation polymerization method.

[0072] Step 2: Add 38.2 g of the capping agent tert-butylaminoethyl methacrylate at 50 °C, and carry out the capping reaction of the polyurethane prepared in Step 1 for 1 h to obtain a polyurethane acrylate prepolymer.

[0073] Step 3: At room temperature, add 56.5 wt% of the polyurethane acrylate prepolymer synthesized in Step 2, 1 wt% of the photoinitiator 1-hydroxycyclohexyl phenyl ketone, 30 wt% of the reactive diluent isobornyl acrylate, and 12.5 wt% of the chain extender 1,5-pentanediamine into a round-bottom flask, mix and stir well, and remove air bubbles under vacuum conditions to obtain a photosensitive resin based on the bio-based polyol PO3G.

[0074] Step 4: Irradiate the photosensitive resin based on the bio-based polyol PO3G with ultraviolet light for 1.5 h to carry out the photocuring reaction of the photosensitive resin. Then, perform secondary thermal curing at 110 °C to break the capping agent at high temperature, release the isocyanate group to react with the chain extender, and finally prepare a photocured material based on the bio-based polyol PO3G.

[0075] Example 7

[0076] This example provides a preparation method of a photocured material based on the bio-based polyol PO3G, including the following steps:

[0077] Step 1: Pre-dehydrate 100 g of bio-based polytrimethylene ether glycol (PO3G) with a molecular weight of 1000 at 110 °C under vacuum for 2 h. Add 0.3 g of the catalyst stannous octoate and 38.4 g of isophthaloyl diisocyanate into a three-necked flask equipped with a thermometer and an electric stirrer. Under a nitrogen atmosphere, react PO3G with isophthaloyl diisocyanate at 75 °C for 4 h to synthesize polyurethane by the condensation polymerization method.

[0078] Step 2: Add 38.2 g of the capping agent dimethylaminoethyl methacrylate at 55 °C and carry out a capping reaction on the polyurethane prepared in Step 1 for 1.5 h to obtain a polyurethane acrylate prepolymer.

[0079] Step 3: At room temperature, add 75 wt% of the polyurethane acrylate prepolymer synthesized in Step 2, 3 wt% of the photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 12 wt% of the reactive diluent isobornyl methacrylate, and 10 wt% of the chain extender 4,4'-diaminodicyclohexylmethane into a round-bottom flask, mix and stir well, and remove air bubbles under vacuum conditions to obtain a photosensitive resin based on the bio-based polyol PO3G.

[0080] Step 4: Irradiate the photosensitive resin based on the bio-based polyol PO3G with ultraviolet light for 0.5 h to carry out the photocuring reaction of the photosensitive resin. Then, perform secondary thermal curing at 100 °C to break the capping agent at high temperature, release the isocyanate group to react with the chain extender, and finally prepare a photocured material based on the bio-based polyol PO3G.

[0081] Comparative Example 1

[0082] This comparative example provides a preparation method of a photocurable material based on non-bio-based polyol PO3G. The preparation steps are basically the same as those in Example 1, except that: in Step 1, the non-bio-based polytrimethylene ether glycol used is poly(tetramethylene ether) glycol produced by Mitsubishi Chemical Corporation of Japan.

[0083] Performance Testing

[0084] The photocurable materials prepared in the above examples and comparative examples were tested for viscosity, tensile strength, elongation at break, and impact strength. The specific test methods are as follows:

[0085] The viscosity was measured using an NDJ-1 type rotational viscometer according to the standard of GB / T 10247-2008. The test environment and the sample temperature were both 25°C;

[0086] The tensile strength was measured using a universal electronic tensile testing machine according to the ASTM D638 standard. Dumbbell-shaped specimens of a certain size were prepared, with a specimen gauge length of 7.6 mm and a tensile rate of 5 mm / min;

[0087] The elongation at break was measured using a universal electronic tensile testing machine according to the ASTM D638 standard. Dumbbell-shaped specimens of a certain size were prepared, with a specimen gauge length of 7.6 mm and a tensile rate of 5 mm / min;

[0088] The impact strength was measured using a pendulum impact tester according to the ASTM D256 standard. Rectangular specimens were prepared for cantilever beam impact testing. The pendulum mass was 0.818 kg, the pendulum speed was 3.5 m / s, and the impact energy was 5.5 J.

[0089] The test results are shown in Table 1.

[0090] Table 1

[0091]

[0092] There are many specific application ways of the present invention. The above description is only the preferred embodiment of the present invention. It should be noted that the above examples are only used to illustrate the present invention and do not limit the protection scope of the present invention. For those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements can be made, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A photosensitive resin based on bio-based polytrimethylene glycol, characterized in that, Comprising the following components in weight percentages: Polyurethane acrylate prepolymer 55 - 75%, Photoinitiator 1 - 3%, Reactive diluent 10 - 30%, Chain extender 10 - 15%; Among them, the polyurethane acrylate prepolymer is prepared by the following method: First, the bio - based polytrimethylene ether glycol is subjected to a condensation reaction with isocyanate under the action of a catalyst to obtain polyurethane; then a capping agent is added to the polyurethane for a capping reaction to obtain it; The number - average molecular weight of the bio - based polytrimethylene ether glycol is 650 - 1000.

2. The photosensitive resin based on bio-based polytetramethylene glycol according to claim 1, wherein The isocyanate is one or more of hexamethylene diisocyanate, 2,2,4 - trimethylhexamethylene diisocyanate, 1,3 - dimethylisocyanatocyclohexane, m - xylylene diisocyanate, 2,4 - toluene diisocyanate, 2,6 - toluene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, p - phenylene diisocyanate, 1,5 - naphthalene diisocyanate; The catalyst is one or more of stannous octoate, dibutyltin dilaurate, zinc isooctoate, zinc naphthenate; The capping agent includes one or more of 2 - hydroxyethyl acrylate, 2 - hydroxypropyl acrylate, 2 - hydroxybutyl acrylate, 2 - hydroxyethyl methacrylate, 2 - hydroxypropyl methacrylate, 2 - hydroxybutyl methacrylate, tert - butylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate.

3. The photosensitive resin based on bio-based polytetramethylene glycol according to claim 1, wherein The reaction temperature of the capping reaction is 45 - 55 °C, and the reaction time is 1 - 2 h.

4. The photosensitive resin based on bio-based polytetramethylene ether glycol according to claim 1, characterized in that, The molar ratio of the bio - based polytrimethylene ether glycol to the isocyanate is 1:2; The addition amount of the catalyst is 0.1% - 0.3% of the weight of the bio - based polytrimethylene ether glycol; The addition amount of the capping agent is 30 - 60% of the weight of the polyurethane.

5. The photosensitive resin based on bio - based polytrimethylene ether glycol according to claim 1, characterized in that The photoinitiator includes one or more of 1 - hydroxycyclohexyl phenyl ketone, 2 - hydroxy - 2 - methyl - 1 - phenyl propanone, 2,4,6 - trimethylbenzoyl - diphenyl phosphine oxide; The reactive diluent includes one or more of monofunctional 2 - hydroxyethyl acrylate, isobornyl acrylate, isobornyl methacrylate; difunctional 1,6 - hexanediol diacrylate, ethylene glycol dimethacrylate, dipropylene glycol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate; and polyfunctional trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate.

6. The photosensitive resin based on bio-based polytetramethylene glycol according to claim 1, characterized in that, The chain extender includes one or more of ethylene glycol, propylene glycol, 1,4 - butanediol, 1,6 - hexanediol, diethylene glycol, 1,4 - cyclohexanediol, ethylenediamine, propylenediamine, 1,5 - pentanediamine, 2 - methyl - 1,5 - pentanediamine, 1,6 - hexanediamine, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl - 4,4 - diaminodicyclohexylmethane, 4,4'-diaminodiphenylmethane.

7. A method for preparing a photosensitive resin based on bio-based polytetramethylene ether glycol according to any one of claims 1-6, characterized in that, It includes the following steps: Fully mix and stir the polyurethane acrylate prepolymer with a photoinitiator, an active diluent, and a chain extender, and remove air bubbles under vacuum conditions to obtain the photosensitive resin.

8. A photocurable material prepared from the photosensitive resin based on bio-based polytrimethylene ether glycol according to any one of claims 1-6.

9. A method for preparing a photocurable material as described in claim 8, characterized in that, It includes the following steps: Carry out a photocuring reaction on the photosensitive resin based on bio-based polytrimethylene ether glycol under ultraviolet light irradiation, and then carry out a thermal curing reaction to obtain it; Among them, the wavelength of the ultraviolet light used in the photocuring reaction is 365 nm, and the irradiation time is 0.5-1.5 h; The curing temperature used in the thermal curing reaction is 100-120 °C, and the curing time is 12 h.

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