Photosensitive polyurethane acrylate and degradable photosensitive resin composition for 3D printing
Photosensitive polyurethane acrylates were prepared by reacting polyhydroxy fatty acid ester alcoholysis products of a specific molecular weight with isocyanates, which solved the problem of insufficient degradability of existing photocurable 3D printing resins, achieved high tensile strength and good biodegradability, and met environmental protection requirements.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SHENZHEN JF BIO PRODUCTS CO LTD
- Filing Date
- 2025-10-28
- Publication Date
- 2026-06-25
AI Technical Summary
While pursuing rapid curing and high performance, existing photopolymer 3D printing resins have neglected the degradability and environmental friendliness of the materials, leading to an increased environmental burden.
Photosensitive polyurethane acrylates are prepared by reacting polyhydroxy fatty acid ester alcoholyses with isocyanate methyl methacrylate or isocyanate ethyl acrylate using a specific molecular weight polyhydroxy fatty acid ester alcoholysis product. This process avoids the introduction of impurities, controls the reaction process, and forms a photosensitive resin composition with good degradability and excellent mechanical properties.
It achieves high tensile strength and good biodegradability, solving the environmental problems of 3D printing materials and meeting environmental protection requirements.
Smart Images
Figure PCTCN2025130637-APPB-I100001
Abstract
Description
Photosensitive polyurethane acrylate and biodegradable photosensitive resin composition for 3D printing Technical Field
[0001] This invention relates to the field of photocurable materials technology, specifically, to a photosensitive polyurethane acrylate and a biodegradable photosensitive resin composition for 3D printing. Background Technology
[0002] Photosensitive resin is a liquid resin that rapidly solidifies upon exposure to light. This photocuring process offers advantages such as being solvent-free, VOC-free, safe, and environmentally friendly. Furthermore, its rapid curing speed facilitates automated production lines, improving production efficiency. Currently, photosensitive resins are widely used in inks, coatings, adhesives, 3D printing, and other fields.
[0003] 3D printing technology, also known as additive manufacturing, is an "additive manufacturing" process that uses digital models to continuously solidify and deposit material layers to ultimately form a three-dimensional object. Its biggest advantage lies in its ability to accurately and quickly construct complex three-dimensional structures, allowing for functional and personalized product designs, and eliminating the need for expensive equipment and tools.
[0004] Current research on photopolymer 3D printing resins largely focuses on achieving properties such as fast curing speed, high temperature resistance, high strength, and high hardness, while neglecting the materials' biodegradability and recyclability. As 3D printing resins become increasingly widely used, the environmental burden of 3D printing materials will be a major challenge in the future.
[0005] Currently, polyurethane acrylates are used as the main raw material to prepare biodegradable photocurable materials. For example, patent application CN 114835860 A describes a biodegradable DLP 3D printing dental crown resin, using hydroxyl polylactic acid as the raw material for polyurethane acrylates; patent application CN109053994 A describes a comb-structured polyurethane acrylate and its preparation method, using an addition reaction between trimethylolpropane and ethyl isocyanate acrylate to synthesize a diol with acrylate side chains for polyurethane acrylate preparation; and patent application CN117050648A describes a UV-curable coating containing a dimer acid structure and its preparation method, which designs an esterification reaction between a dimer acid and a linear diol to obtain a polyester diol with a low proportion of amorphous components, thus obtaining polyurethane acrylate oligomers. It is evident that the polyols used in the preparation of polyurethane acrylates mentioned above are usually polyethers or synthetic polyesters. During these methods, various impurities and functional groups are introduced, affecting the degradation performance of the polyurethane acrylates. Summary of the Invention
[0006] Based on this, the present invention aims to overcome at least one defect of the prior art and provide a photosensitive polyurethane acrylate and a biodegradable photosensitive resin composition for 3D printing. This biodegradable photosensitive resin composition for 3D printing not only meets the performance requirements of 3D printing and has excellent mechanical properties, but also has good material biodegradability and is environmentally friendly.
[0007] The first aspect of the present invention provides a photosensitive polyurethane acrylate, which is a reaction product of polyhydroxyalkanoate hydrolysate and isocyanate ethyl methacrylate or isocyanate ethyl acrylate, wherein the number average molecular weight of the polyhydroxyalkanoate hydrolysate is 1000 to 3000.
[0008] The second aspect of the present invention provides a method for preparing photosensitive polyurethane acrylate, which is prepared by the following method: a polyhydroxy fatty acid ester alcoholysis product, a polymerization inhibitor, and a catalyst are placed in a reaction vessel, heated and stirred until homogeneous, and the temperature is controlled at 50-60°C. At this temperature, isocyanate ethyl methacrylate or isocyanate ethyl acrylate is added at a uniform rate. After the temperature is raised to 80-90°C, the reaction is carried out for 3-4 hours. The isocyanate group content is monitored, and the material is discharged when the isocyanate group content in the reaction system is lower than 0.05%, thus obtaining photosensitive polyurethane acrylate.
[0009] A third aspect of the present invention provides a biodegradable photosensitive resin composition for 3D printing, comprising the following components in parts by weight: 55-70 parts of the above-described photosensitive polyurethane acrylate or the photosensitive polyurethane acrylate prepared by the above-described preparation method; 30-50 parts of reactive diluent; 1-3 parts of photoinitiator; and 0.2-1 parts of polymerization inhibitor.
[0010] The beneficial effects of this invention are as follows: This application uses polyhydroxyalkanoate alcoholysis products of a specific molecular weight as one of the raw materials for synthesizing photosensitive polyurethane acrylates. These polyhydroxyalkanoate alcoholysis products of a specific molecular weight are monohydric alcohols or a mixture of polyhydric alcohols. The hydroxyl groups contained in their chain segments react with isocyanates to form a polyurethane structure. The final product has good degradability, high tensile strength, and excellent mechanical properties. Moreover, the isocyanates provided by isocyanate ethyl methacrylate or isocyanate ethyl acrylate can better control the synthesis process. The reaction process of isocyanate groups (-NCO) and hydroxyl groups (-OH) has low viscosity and good stability. Furthermore, no solvent needs to be added and no other substances are introduced. The preparation process is short and the environmental performance is good. Embodiments of the present invention
[0011] The embodiments of the present invention are for illustrative purposes only and should not be construed as limiting the present invention.
[0012] For simplicity, this paper only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an undefined range; and any lower limit can be combined with other lower limits to form an undefined range, just as any upper limit can be combined with any other upper limit to form an undefined range. Furthermore, although not explicitly stated, every point or individual value between the endpoints of a range is included within that range. Therefore, each point or individual value can serve as its own lower or upper limit and be combined with any other point or individual value, or with other lower or upper limits, to form an undefined range.
[0013] The foregoing description of this application is not intended to describe every disclosed implementation or method. Instead, the following description provides more specific examples of exemplary embodiments. Throughout the application, guidance is provided through a series of embodiments that can be used in various combinations. The examples listed are representative only and should not be construed as exhaustive.
[0014] The first aspect of the present invention provides a photosensitive polyurethane acrylate, which is a reaction product of polyhydroxyalkanoate hydrolysate and isocyanate ethyl methacrylate or isocyanate ethyl acrylate, wherein the number average molecular weight of the polyhydroxyalkanoate hydrolysate is 1000 to 3000.
[0015] In one preferred embodiment, the polyhydroxyalkanoate hydrolysate is one or more of a diol or a mixture of polyols.
[0016] In one preferred embodiment, the biodegradability of the photosensitive polyurethane acrylate is ≥90%.
[0017] The second aspect of the present invention provides a method for preparing photosensitive polyurethane acrylate, which is prepared by the following method: a polyhydroxy fatty acid ester alcoholysis product, a polymerization inhibitor, and a catalyst are placed in a reaction vessel, heated and stirred until homogeneous, and the temperature is controlled at 50-60°C. At this temperature, isocyanate ethyl methacrylate or isocyanate ethyl acrylate is added at a uniform rate. After the temperature is raised to 80-90°C, the reaction is carried out for 3-4 hours. The isocyanate group content is monitored, and the material is discharged when the isocyanate group content in the reaction system is lower than 0.05%, thus obtaining photosensitive polyurethane acrylate.
[0018] In one preferred embodiment, the polyhydroxyalkanoate alcoholysis product is prepared by the following method: polyhydroxyalkanoate and chloroform are added to a reaction vessel at a mass ratio of 1:(5-20), heated and stirred until fully dissolved, and the temperature is controlled at 40-50°C. An esterification reaction is carried out by adding 3-8 times the molar amount of diol ester exchanger and 1-3 wt‰ of catalyst. The reaction is carried out for 20-25 hours, followed by vacuum polycondensation for 0.5-3 hours. After the reaction is completed, the system is allowed to cool naturally to room temperature. The solution is then poured into a separatory funnel, washed with water at least 2-5 times, filtered under reduced pressure to obtain a yellow liquid, and concentrated by rotary evaporation. The concentrated liquid is poured into ice-cold methanol and stirred until precipitation occurs. After vacuum filtration, a yellow powder is obtained, which is then dried under vacuum to constant weight to obtain the polyhydroxyalkanoate alcoholysis product.
[0019] In one preferred embodiment, the polyhydroxy fatty acid ester includes one or more of polyhydroxybutyrate, hydroxybutyric acid copolyester, hydroxybutyrate hexanoate copolyester, poly-3-hydroxybutyrate-4-hydroxybutyrate, and poly-3-hydroxybutyl ester-co-3-hydroxyhexanoate, wherein the number average molecular weight of the polyhydroxy fatty acid ester is 40,000 to 50,000.
[0020] This invention directly uses the alcoholysis products of polyhydroxyalkanoates to prepare photosensitive polyurethane acrylates, avoiding the introduction of other groups during the production of polyols from polyethers or polyesters, which ultimately affects the degradability of photosensitive polyurethane acrylates. Furthermore, because it uses polyhydroxyalkanoates with specific molecular weights for the preparation of the alcoholysis products, it allows for more precise control of the number-average molecular weight of the alcoholysis products, effectively ensuring the degradability and mechanical properties of the photosensitive polyurethane acrylates. This is because the polyhydroxyalkanoate alcoholysis products contain hydroxyl groups, which can react with isocyanates to form a polyurethane structure. Moreover, the use of isocyanate ethyl methacrylate or isocyanate ethyl acrylate to provide isocyanates allows for excellent control of the synthesis progress during the process, facilitating the tracking of -NCO content and precise control of the hydroxyl and -NCO content in the reaction system. This reaction process exhibits low viscosity and good stability. Furthermore, the reaction between -NCO and -OH requires no additional reaction media or solvents, resulting in a short preparation process and good environmental performance.
[0021] A third aspect of the present invention provides a biodegradable photosensitive resin composition for 3D printing, comprising the following components in parts by weight: 55-70 parts of the above-described photosensitive polyurethane acrylate or the photosensitive polyurethane acrylate prepared by the above-described preparation method; 30-50 parts of reactive diluent; 1-3 parts of photoinitiator; and 0.2-1 parts of polymerization inhibitor.
[0022] In one preferred embodiment, the reactive diluent is a compound having a (meth)acrylate group and / or an acrylamide group. Specifically, it is one or more of the following: hydroxyethyl (meth)acrylate, tetrahydrofuran (meth)acrylate, isobornyl (meth)acrylate, trimethylolpropane-formaldehyde acrylate, and acrylmorpholine.
[0023] In one preferred embodiment, the photoinitiator is one or more of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, bis(2,4,6-trimethylbenzoylphenyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphosphonate, 1-hydroxy-1-methylethylphenyl ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2-isopropylthioxanthraphenone, and 4-chlorobenzophenone.
[0024] In one preferred embodiment, the polymerization inhibitor may be one or more of p-methoxyphenol, hydroquinone, p-tert-butylcatechol, 2,6-di-tert-butyl-p-methylphenol, 4,4'-dihydroxybiphenyl, and bisphenol A.
[0025] In one preferred embodiment, the biodegradability of the product obtained by 3D printing from the above-described biodegradable photosensitive resin composition is 61.5 to 85.9%.
[0026] In one preferred embodiment, the tensile strength of the product obtained by 3D printing from the above-described biodegradable photosensitive resin composition for 3D printing is 52.8 to 69.3 MPa.
[0027] The biodegradable photosensitive resin composition prepared by the present invention uses photosensitive polyurethane acrylate with good biodegradability as raw material. It has a simple composition and high environmental friendliness. Its products not only meet the high tensile strength requirements of 3D printing resin, but also have a better biodegradability rate, thus solving the environmental burden of current 3D printing materials.
[0028] Example
[0029] The polyhydroxy fatty acid ester alcoholysis product 1 described in the following examples was prepared by the following method:
[0030] Polyhydroxyalkanoate (molecular weight approximately 50,000) and chloroform were added to a reaction vessel at a mass ratio of 1:10. A condenser was installed, and the mixture was stirred and heated to 45°C until fully dissolved. Then, 1,4-butanediol (5 molar amounts of polyhydroxyalkanoate) and 2 wt‰ of catalyst were added for esterification. The reaction was carried out for 24 hours, followed by vacuum polycondensation for 1 hour. After the reaction was complete, the system was allowed to cool naturally to room temperature. The solution was then poured into a water-washing container, washed three times, and filtered under reduced pressure to obtain a yellow liquid. The liquid was then concentrated by rotary evaporation. The concentrated liquid was poured into ice-cold methanol and stirred until precipitation occurred. After vacuum filtration, a yellow powder was obtained, which was dried under vacuum at 40°C to constant weight to obtain polyhydroxyalkanoate alcoholysis product 1. The number average molecular weight of polyhydroxyalkanoate alcoholysis product 1 was approximately 1600 (hydroxyl groups were 70.1 mg KOH / g).
[0031] The polyhydroxyalkanoate alcoholysis product 2 described in the following examples was prepared by the following method: Polyhydroxyalkanoate (molecular weight approximately 40,000) and chloroform were added to a reaction vessel at a mass ratio of 1:10. A condenser was installed, and the mixture was stirred and heated to 45°C until fully dissolved. Five times the molar amount of the polyhydroxyalkanoate diol ester exchanger 1,4-butanediol and 2 wt‰ of catalyst were added for esterification. The reaction was carried out for 24 hours, followed by vacuum polycondensation for 0.5 hours. After the reaction was completed, the system was allowed to cool naturally to room temperature. The solution was then poured into a water-washing container, washed three times, and filtered under reduced pressure to obtain a yellow liquid. The liquid was then concentrated by rotary evaporation. The concentrated liquid was poured into ice-cold methanol and stirred until precipitation occurred. After filtration under reduced pressure, a yellow powder was obtained. This powder was dried under vacuum at 40°C to constant weight to obtain polyhydroxyalkanoate alcoholysis product 2. The number average molecular weight of polyhydroxyalkanoate alcoholysis product 2 was approximately 1000 (hydroxyl value 112.2 mgKOH / g).
[0032] The polyhydroxyalkanoate alcoholysis product 3 described in the following examples was prepared by the following method: Polyhydroxyalkanoate (molecular weight approximately 50,000) and chloroform were added to a reaction vessel at a mass ratio of 1:10. A condenser was installed, and the mixture was stirred and heated to 40-50°C until fully dissolved. Then, 1,4-butanediol, a diol ester exchanger in a molar ratio equal to that of polyhydroxyalkanoate, and tetrabutyl titanate, a catalyst in a total mass of 2 wt‰, were added for esterification. The reaction was carried out for 24 hours, followed by vacuum polycondensation for 3 hours. After the reaction was completed, the system was allowed to cool naturally to room temperature. The solution was then poured into a water washing container, washed three times with water, and filtered under reduced pressure to obtain a yellow liquid. After rotary evaporation, a concentrated liquid was obtained. The concentrated liquid was poured into ice-cold methanol and stirred until precipitation occurred. After vacuum filtration, a yellow powder was obtained. The powder was dried under vacuum at 40°C to constant weight to obtain polyhydroxyalkanoate alcoholysis product 3. The number average molecular weight of polyhydroxyalkanoate alcoholysis product 3 was approximately 3000 (hydroxyl value 37.4 mg KOH / g).
[0033] The photosensitive polyurethane acrylate 1 described in the following examples was prepared by the following method:
[0034] Polyhydroxyalkanoate alcoholysis product 1, along with a polymerization inhibitor and a catalyst, was placed in a reaction vessel, heated, and stirred until homogeneous. The temperature was controlled at 50–60°C. At this temperature, isocyanate ethyl methacrylate or isocyanate ethyl acrylate was added at a uniform rate. The mixture was then heated to 85°C and reacted for 3 hours. The isocyanate group (-NCO) content was monitored. The product was discharged when the isocyanate group (-NCO) content in the reaction system was below 0.05%, yielding photosensitive polyurethane acrylate. The molar ratio of hydroxyl groups in the polyhydroxyalkanoate alcoholysis product to isocyanate ethyl acrylate was (1.01:1). The amount of the polymerization inhibitor was 0.1% of the total mass of the polyhydroxyalkanoate alcoholysis product and isocyanate ethyl acrylate. The amount of the catalyst was also 0.1% of the total mass of the polyhydroxyalkanoate alcoholysis product and isocyanate ethyl acrylate.
[0035] The preparation process of photosensitive polyurethane acrylate 2 described in the following examples is similar to that of photosensitive polyurethane acrylate 1, except that polyhydroxyalkanoate ester hydrolysate 2 is used.
[0036] The preparation process of photosensitive polyurethane acrylate 3 described in the following examples is similar to that of photosensitive polyurethane acrylate 1, except that polyhydroxyalkanoate hydrolysate 3 is used.
[0037] The photosensitive polyurethane acrylate 4 described in the following examples was prepared by the following method:
[0038] Polyhydroxyalkanoate alcoholysis product 1, along with a polymerization inhibitor and a catalyst, was placed in a reaction vessel, heated, and stirred until homogeneous. The temperature was controlled at 50–60°C. At this temperature, isocyanate ethyl methacrylate or isocyanate ethyl acrylate was added at a uniform rate. The mixture was then heated to 85°C and reacted for 4 hours. The -NCO content was monitored, and the product was discharged when the -NCO content in the reaction system was below 0.05%, yielding photosensitive polyurethane acrylate. The isocyanate molar ratio of the hydroxyl groups in the polyhydroxyalkanoate alcoholysis product to that in ethyl isocyanate acrylate was (1.02:1). The amount of the polymerization inhibitor was 0.05% of the total mass of the polyhydroxyalkanoate alcoholysis product and ethyl isocyanate acrylate. The amount of the catalyst was also 0.05% of the total mass of the polyhydroxyalkanoate alcoholysis product and ethyl isocyanate acrylate.
[0039] The photosensitive polyurethane acrylate 5 described in the following examples was prepared by the following method:
[0040] Polyhydroxyalkanoate alcoholysis product 1, along with a polymerization inhibitor and a catalyst, was placed in a reaction vessel, heated, and stirred until homogeneous. The temperature was controlled at 55°C. At this temperature, isocyanate methacrylate or ethyl isocyanate acrylate was added at a uniform rate. The reaction was carried out for 3 hours, and the -NCO content was monitored. The product was discharged when the -NCO content in the reaction system was below 0.05%, yielding photosensitive polyurethane acrylate. The molar ratio of the polyhydroxyalkanoate alcoholysis product to isocyanate methacrylate was (1.05:1). The amount of the polymerization inhibitor was 0.2% of the total mass of the polyhydroxyalkanoate alcoholysis product and ethyl isocyanate acrylate. The amount of the catalyst was also 0.2% of the total mass of the polyhydroxyalkanoate alcoholysis product and ethyl isocyanate acrylate.
[0041] Photosensitive polyurethane acrylate 1, 2, 3, 4, and 5 were tested according to the biodegradability test method in GB / T 19277.1. The biodegradability rates obtained were 96%, 93%, 91%, 96%, and 95%, respectively. It can be seen that the biodegradability rate of the photosensitive polyurethane acrylate described in this application is ≥90%, and the photosensitive polyurethane acrylate has good biodegradability.
[0042] Example 1
[0043] A biodegradable photosensitive resin composition for 3D printing comprises the following components in parts by weight: photosensitive polyurethane acrylate 1:57 parts; acrylamide morpholine: 20 parts; trimethylolpropane formal acrylate: 20 parts; 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide: 2.5 parts; p-methoxyphenol: 0.5 parts. The preparation process is as follows: the above components are mixed and stirred sequentially at 30°C and a rotation speed of 300-400 r / min for 60 min. After uniform stirring, the mixture is allowed to stand to defoam, yielding the 3D printing photocurable composition.
[0044] Example 2
[0045] A biodegradable photosensitive resin composition for 3D printing, the composition and preparation process of which are the same as those in Example 1, the only difference being that the photosensitive polyurethane acrylate used in this Example 2 is photosensitive polyurethane acrylate 2.
[0046] Example 3
[0047] A biodegradable photosensitive resin composition for 3D printing, the composition and preparation process of which are the same as those in Example 1, the only difference being that the photosensitive polyurethane acrylate used in this Example 3 is photosensitive polyurethane acrylate 3.
[0048] Example 4
[0049] A biodegradable photosensitive resin composition for 3D printing, the composition and preparation process of which are the same as those in Example 1, the only difference being that the photosensitive polyurethane acrylate used in Example 4 is photosensitive polyurethane acrylate 4.
[0050] Example 5
[0051] A biodegradable photosensitive resin composition for 3D printing, the composition and preparation process of which are the same as those in Example 1, the only difference being that the photosensitive polyurethane acrylate used in this Example 5 is photosensitive polyurethane acrylate 5.
[0052] Example 6
[0053] A biodegradable photosensitive resin composition for 3D printing comprises the following components by weight: photosensitive polyurethane acrylate 1:55 parts; acrylmorpholine: 30 parts; trimethylolpropane-formaldehyde acrylate: 20 parts; 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide: 3 parts; p-methoxyphenol: 1 part. The preparation process is as follows: the above components are mixed and stirred sequentially at 30°C and a rotation speed of 300-400 r / min for 60 min. After uniform stirring, the mixture is allowed to stand to defoam, yielding the 3D printing photocurable composition.
[0054] Example 7
[0055] A biodegradable photosensitive resin composition for 3D printing comprises the following components in parts by weight: photosensitive polyurethane acrylate 1:70 parts; acrylamide morpholine: 30 parts; trimethylolpropane formal acrylate: 20 parts; 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide: 1 part; p-methoxyphenol: 0.2 parts. The preparation process is as follows: the above components are mixed and stirred sequentially at 30°C and a rotation speed of 300-400 r / min for 60 min. After uniform stirring, the mixture is allowed to stand to defoam, yielding the 3D printing photocurable composition.
[0056] Example 8
[0057] A biodegradable photosensitive resin composition for 3D printing comprises the following components in parts by weight: photosensitive polyurethane acrylate 1:57 parts; isobornyl acrylate: 40 parts; trimethylolpropane-formaldehyde acrylate: 20 parts; ethyl 2,4,6-trimethylbenzoylphosphonate: 2.5 parts; hydroquinone: 0.5 parts. The preparation process is as follows: the above components are mixed and stirred sequentially at 30°C and a rotation speed of 300-400 r / min for 60 min. After uniform stirring, the mixture is allowed to stand to defoam, yielding the 3D printing photocurable composition.
[0058] Comparative Example 1
[0059] A biodegradable photosensitive resin composition for 3D printing is provided. Its components and preparation process are largely the same as in Example 3, except that the photosensitive polyurethane acrylate is different. The number-average molecular weight of the polyhydroxyalkanoate hydrolysate synthesized from the photosensitive polyurethane acrylate used in Comparative Example 1 is approximately 4000. The preparation process of the polyhydroxyalkanoate hydrolysate in Comparative Example 1 is as follows:
[0060] Polyhydroxyalkanoate (molecular weight approximately 50,000) and chloroform were added to a reaction vessel at a mass ratio of 1:10. A condenser and liquid seal device were installed. The mixture was stirred and heated to 40–50°C until fully dissolved. Then, 1,4-butanediol, a diol transesterification agent in a molar ratio equal to that of the polyhydroxyalkanoate, and 2 wt‰ of catalyst were added to initiate an esterification reaction. The reaction was carried out for 24 hours, followed by vacuum polycondensation for 4.5 hours. After the reaction was completed, the system was allowed to cool naturally to room temperature. The solution was then poured into a separatory container, washed three times with water, and filtered under reduced pressure to obtain a yellow liquid. After rotary evaporation, a concentrated liquid was obtained. The concentrated liquid was poured into ice-cold methanol and stirred until precipitation occurred. After vacuum filtration, a yellow powder was obtained, which was then dried under vacuum at 40°C to constant weight to obtain the polyhydroxyalkanoate alcoholysis product. The number average molecular weight of the polyhydroxyalkanoate alcoholysis product was approximately 4000 (hydroxyl groups were 28.05 mg KOH / g).
[0061] Comparative Example 2
[0062] A biodegradable photosensitive resin composition for 3D printing is generally the same as that in Example 3 in terms of composition and preparation process, except that the photosensitive polyurethane acrylate is different. The number average molecular weight of the polyhydroxyalkanoate hydrolysate synthesized by the photosensitive polyurethane acrylate used in Comparative Example 2 is about 900. The preparation process of the polyhydroxyalkanoate hydrolysate in Comparative Example 2 is generally the same as that in Comparative Example 1, except that the molecular weight of the polyhydroxyalkanoate used is about 30,000.
[0063] Comparative Example 3
[0064] A biodegradable photosensitive resin composition for 3D printing comprises the following components in parts by weight: photosensitive polyurethane acrylate 1:50 parts; acrylmorpholine: 20 parts; trimethylolpropane-formaldehyde acrylate: 20 parts; 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide: 2.5 parts; p-methoxyphenol: 0.5 parts. The preparation process is as follows: the above components are mixed and stirred sequentially at 30°C and a rotation speed of 300-400 r / min for 60 min. After uniform stirring, the mixture is allowed to stand to defoam, yielding the 3D printing photocurable composition.
[0065] The viscosities of the compositions of Examples 1-8 and Comparative Examples 1-3 were measured using a rotational rheometer at room temperature (25°C). The compositions were then subjected to photopolymerization 3D printing, with the following procedure: A sample strip was printed using an Anycubic LCD 3D printer, with a slice thickness of 50 µm. Each layer was exposed for 3 seconds, and the printing temperature was controlled at 30°C. After printing, the printed part was manually removed, ultrasonically cleaned for 2 minutes, and then UV cured for 5 minutes. The printed material was tested for tensile properties and elongation at break according to ASTM D638, and for flexural properties according to ASTM D790. Biodegradability was tested according to GB / T 19277.1. The measurement results are shown in Table 1 below.
[0066] Table 1
[0067]
[0068] As can be clearly seen from Table 1, within the range of the required ratio and molecular weight of the polyhydroxyalkanoate hydrolysate as specified in this invention, the compositions of Examples 1-8 have moderate viscosity, resulting in a high success rate in the 3D printing process. The printed products also exhibit high tensile strength, good flexural strength, and a high biodegradability, thus demonstrating the environmental friendliness of the material.
[0069] As can be seen from Comparative Example 1, when a biodegradable photosensitive resin composition is prepared using a material with a number-average molecular weight of approximately 4000 for polyhydroxyalkanoate hydrolysate, the viscosity of the composition is too high, making 3D printing impossible. In Comparative Example 2, the number-average molecular weight of the polyhydroxyalkanoate hydrolysate is too low, which also fails to meet the requirements. It is evident that the selection of the number-average molecular weight of the polyhydroxyalkanoate hydrolysate directly affects the success or failure of the printing.
[0070] As can be seen from Comparative Example 3, when the composition of the composition is adjusted and the mass ratio of photosensitive polyurethane acrylate is reduced, it can meet the printing requirements, but the performance of the product is very poor. The tensile strength of the product is reduced, and other properties are also reduced. The main biodegradability rate is only 49.1%, which is not ideal.
[0071] In summary, the photosensitive polyurethane acrylate of the present invention has good mechanical properties and biodegradability, making it more suitable for the development of biodegradable materials. The biodegradable photosensitive resin composition and its 3D printed products also have good biodegradability, meeting environmental protection requirements.
[0072] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.
Claims
1. A photosensitive polyurethane acrylate, characterized in that, The photosensitive polyurethane acrylate is a reaction product of polyhydroxy fatty acid ester alcoholysis product and isocyanate ethyl methacrylate or isocyanate ethyl acrylate, wherein the number average molecular weight of the polyhydroxy fatty acid ester alcoholysis product is 1000-3000.
2. The photosensitive polyurethane acrylate according to claim 1, characterized in that, The polyhydroxy fatty acid ester alcoholysis product is one or more of diols and polyols.
3. The photosensitive polyurethane acrylate according to claim 1, characterized in that, The biodegradability of the photosensitive polyurethane acrylate is ≥90%.
4. A method for preparing photosensitive polyurethane acrylate as described in any one of claims 1-3, characterized in that, It is prepared by the following method: Polyhydroxyalkanoate alcoholysis product, polymerization inhibitor, and catalyst are placed in a reaction vessel, heated and stirred until homogeneous, and the temperature is controlled at 50-60℃. At this temperature, isocyanate ethyl methacrylate or isocyanate ethyl acrylate is added at a uniform rate. The temperature is then raised to 80-90℃, and the reaction is carried out for 3-4 hours. The isocyanate group content is monitored, and the material is discharged when the isocyanate group content in the reaction system is lower than 0.05%, yielding photosensitive polyurethane acrylate. The molar ratio of hydroxyl groups to isocyanate in the polyhydroxyalkanoate alcoholysis product is (1.01-1.05):1; the amount of the polymerization inhibitor is 0.05-0.2% of the total mass of the polyhydroxyalkanoate alcoholysis product and the polyhydroxyalkanoate isocyanate or isocyanate; the amount of the catalyst is 0.05-0.2% of the total mass of the polyhydroxyalkanoate alcoholysis product and the polyhydroxyalkanoate isocyanate or isocyanate.
5. The method for preparing photosensitive polyurethane acrylate according to claim 4, characterized in that, The polyhydroxy fatty acid ester alcoholysis product was prepared by the following method: Polyhydroxy fatty acid ester and chloroform are added to a reaction vessel at a mass ratio of 1:(5-20), heated and stirred until fully dissolved, and the temperature is controlled at 40-50℃. Diol ester exchange agent of 3-8 times the molar number of polyhydroxy fatty acid ester and catalyst of 1-3 wt‰ are added to carry out esterification reaction. The reaction is carried out for 20-25 hours, followed by vacuum polycondensation for 0.5-3 hours. After the reaction is completed, the system is allowed to cool naturally to room temperature. The solution was then washed with water at least 2 to 5 times, filtered under reduced pressure to obtain a yellow liquid, and concentrated by rotary evaporation. The concentrated liquid was poured into ice-cold methanol and stirred until precipitation occurred. After filtration under reduced pressure, a yellow powder was obtained. After vacuum drying to constant weight, the polyhydroxy fatty acid ester alcoholysis product was obtained.
6. The method for preparing photosensitive polyurethane acrylate according to claim 5, characterized in that, The polyhydroxy fatty acid ester includes one or more of polyhydroxybutyrate, hydroxybutyric acid copolyester, hydroxybutyric acid hexanoate copolyester, poly-3-hydroxybutyrate-4-hydroxybutyrate, and poly-3-hydroxybutyl ester-co-3-hydroxyhexanoate, wherein the number average molecular weight of the polyhydroxy fatty acid ester is 40,000 to 50,000.
7. A biodegradable photosensitive resin composition for 3D printing, characterized in that, Includes the following components, calculated in parts by weight: Photosensitive polyurethane acrylate as described in any one of claims 1-3, or photosensitive polyurethane acrylate prepared by any one of claims 4-6: 55-70 parts; Reactive diluent: 30-50 parts; Photoinitiator: 1-3 parts; Polymerization inhibitor: 0.2 to 1 part.
8. The biodegradable photosensitive resin composition for 3D printing according to claim 7, characterized in that, The reactive diluent is a compound with (meth)acrylate or / and acrylamide functional groups.
9. The biodegradable photosensitive resin composition for 3D printing according to claim 7, characterized in that, The photoinitiator is one or more of the following: 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, bis(2,4,6-trimethylbenzoylphenyl)phosphine oxide, ethyl 2,4,6-trimethylbenzoylphosphonate, 1-hydroxy-1-methylethylphenyl ketone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2-isopropylthioxanthraphenone, and 4-chlorobenzophenone.
10. The biodegradable photosensitive resin composition for 3D printing according to any one of claims 7-9, characterized in that, The biodegradability of the products obtained by 3D printing from the biodegradable photosensitive resin composition is 61.5-85.9%.