Low-viscosity high-crosslinking hyperbranched polyurethane acrylate, preparation method thereof and UV (ultraviolet) curing nonmetal knife line mold

Abstract

The invention provides a low-viscosity high-crosslinking hyperbranched polymer as well as a preparation method and application thereof. According to the product, the internal stress of a system is greatly reduced, the volume shrinkage phenomenon after curing is avoided, and the adhesive capacity between the product and a base material is enhanced; meanwhile, the obtained hyperbranched polymer is adjustable in terminal group and low in viscosity, and can replace or partially replace a volatile reactive diluent, so that the emission of VOC (volatile organic compounds) is greatly reduced, and the green development of the photocuring polymer is promoted; the organic silicon monomer is introduced into a hyperbranched polymer system, so that the light-cured resin obtains a certain deflection, and the universality of the light-cured resin in preparation of a non-metal knife line mold is improved by combining a polymer material, structural design and an injection molding technology.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a low-viscosity and high-crosslinking hyperbranched polyurethane acrylate, a preparation method thereof, and a UV-curable non-metal knife line die. Background Art

[0002] Nowadays, packaging printing such as paper boxes or cards has penetrated into people's lives and has become an indispensable part. However, traditional metal knife plate dies pose a great challenge to the practical operation ability of technicians, and the cumbersome plate-making and alignment forms are difficult to meet the needs of people's high-speed and efficient life and production. Non-metal knife line dies are key components of digital die-cutting processing equipment and can effectively promote the development process of intelligent manufacturing. Chinese patents CN102985612B and CN106457735B mention preparing surface-bonded inlays with polymers as the main body, forming slender strips on the bottom die to obtain knife ruler punching dies, which have made great progress in improving packaging printing efficiency. Invention patent CN114889121B proposes a manufacturing device and a manufacturing method for a non-metal knife line die, using a photosensitive resin that forms rigid lines with certain mechanical properties under UV as the knife line die material, combining 3D printing technology, simplifying the manufacturing process of the knife line die, realizing the application of fully automatic indentation equipment, and promoting the long-term development of the domestic packaging printing industry. However, such high-viscosity photocurable resins have difficulties in the blending process and are not easy to defoam.

[0003] The main components of UV-curable resins include oligomers, reactive diluents, photoinitiators, and various additives. Solutions to reduce the viscosity of the resin system are as follows: adjusting the system viscosity by adding a large amount of reactive diluent monomers to improve the fluidity. However, the extensive use of reactive diluents not only reduces the mechanical properties of the material, but also reduces the adhesion to the substrate and even causes cracking due to its large shrinkage internal stress.

[0004] Hyperbranched polymers, as a type of polymer with a novel topological structure, endow their internal cavities and unique three-dimensional ellipsoidal structures with excellent solubility, low viscosity, and no entanglement between molecules. Hyperbranched polyurethane acrylates combine the advantages of polyurethane resins, hyperbranched polymers, and UV-curing technology, such as high flexibility, good chemical resistance, easy mixing with other materials, short curing time, and environmental friendliness. Chinese patent CN104211903B discloses a hyperbranched polyurethane acrylate with glycerol (or pentaerythritol) as the core. Chinese patent CN1791621 discloses a method for preparing hyperbranched polyurethanes using AB2 or A2B monomers generated by the reaction of acrylic hydroxy esters and monoamino dihydroxy. However, these methods either have side reactions of intramolecular cyclization, or there is a risk of gelation in the system, or the toughness of the cured film is poor, affecting the application.

[0005] Therefore, it is very necessary to develop a fast-curing resin with low viscosity, fast flow leveling, high strength and toughness. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a preparation method of a low-viscosity, high-crosslinking hyperbranched polyurethane acrylate. The photocuring resin provided by the present invention has the characteristics of low viscosity, fast flow leveling and good impact resistance.

[0007] The present invention provides a preparation method of a low-viscosity, high-crosslinking hyperbranched polyurethane acrylate, comprising the following steps:

[0008] A) Dissolve thiol, diisocyanate and catalyst in a solvent, and carry out a thiol-isocyanate click polymerization reaction under an inert gas atmosphere to obtain a polythiourethane PTU;

[0009] B) Mix the above-mentioned polythiourethane PTU and a hydroxyl-terminated polydimethylsiloxane, stir, and then add a mixed solution of a hydroxyacrylate monomer, a catalyst and an inhibitor, and obtain the product after a polymerization reaction.

[0010] The present invention uses a one-pot method to introduce silicone and terminate with double bonds to obtain a silicone-modified hyperbranched polymer with multiple unsaturated double bonds.

[0011] For the low-viscosity, high-crosslinking hyperbranched polyurethane acrylate provided by the present invention, thiol, diisocyanate and catalyst are dissolved in a solvent, and a thiol-isocyanate click polymerization reaction is carried out under an inert gas atmosphere to obtain a polythiourethane PTU, and then it is obtained after rotary evaporation and drying. The present invention does not limit the specific methods of rotary evaporation and drying, and those well-known to those skilled in the art can be used.

[0012] The inert gas described in the present invention is preferably nitrogen. The solvent is toluene, tetrahydrofuran, N,N-dimethylformamide, 1,4-dioxane.

[0013] According to the present invention, the diisocyanate is one of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, trimethylhexane diisocyanate, 4,4'-diisocyanate dicyclohexylmethane.

[0014] The thiol is trimethylolpropane tris(3-mercaptopropionate).

[0015] The two -NCO groups in the diisocyanate of the present invention have different reaction activities. In the early stage of polymerization, by adjusting the molar amount of the diisocyanate and the thiol, reaction intermediates with different end group structures can be obtained, such as formula I or formula II;

[0016]

[0017] Wherein:

[0018] During the continuous reaction, this difference in reactivity can effectively avoid the formation of gel phenomena during the polymerization of hyperbranched polymers and obtain a uniform polymer network structure.

[0019] According to the present invention, the molar ratio of the diisocyanate to the thiol is (1-4):(2-1);

[0020] In some embodiments, the molar ratio of the diisocyanate to the thiol is (2-3):1;

[0021] In some embodiments, the molar ratio of the diisocyanate to the thiol is 0.062:0.03.

[0022] According to the present invention, the catalyst is triethylamine, and the catalyst dosage is 0.05%-0.2% of the total mass of the diisocyanate and the thiol;

[0023] In some embodiments, the catalyst is triethylamine, and the catalyst dosage is 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt% of the total mass of the diisocyanate and the thiol; or a range value between any two of the above.

[0024] According to the present invention, the reaction temperature is 20-25°C; the reaction time is 1-8 h; after the reaction is completed, the solvent is removed by rotary evaporation, and then the product is obtained by vacuum drying;

[0025] The present invention utilizes thiol-isocyanate click polymerization to synthesize polythiourethane PTU with adjustable backbone and end groups by regulating the amount of substance of the thiol.

[0026] The above-mentioned polythiourethane PTU is added to hydroxyl-terminated polydimethylsiloxane, stirred and ultrasonically dispersed, and then the temperature is raised and a mixed solution of hydroxyacrylate monomer, catalyst and inhibitor is slowly added dropwise. When the isocyanate groups react completely, the organosilicon-modified hyperbranched polymer Si-HBP is obtained.

[0027] Among them, the specific rate of dropping the mixed solution is 3-10 ml / h; the specific temperature for raising the temperature includes 40-60°C; the reaction time is 4-12 h.

[0028] The molecular weight of the hydroxyl-terminated polydimethylsiloxane described in the present invention is 500-2000, and the molecular weight can be 500, 600, 700, 800, 900, 1000, 1500 or 2000; or a range value between any two of the above.

[0029] The molar ratio of polythiourethane PTU to hydroxyl-terminated polydimethylsiloxane and hydroxyacrylate monomer is 1:(5-20):(10-30).

[0030] In some specific embodiments, the molar ratio of polythiourethane PTU, hydroxyl-terminated polydimethylsiloxane, and hydroxy acrylate monomers is 1:(7 - 18):(12 - 28).

[0031] In some specific embodiments, the molar ratio of polythiourethane PTU, hydroxyl-terminated polydimethylsiloxane, and hydroxy acrylate monomers is 1:(9 - 16):(15 - 25).

[0032] The catalyst in the present invention is dibutyltin dilaurate or triethylamine, and its dosage is 0.05 - 0.2% of the total mass of PTU, hydroxyl-terminated polydimethylsiloxane, and hydroxy acrylate monomers; specifically, it can be 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%; or the range values between any two of the above.

[0033] The inhibitor is hydroquinone, and its dosage is 0.05 - 0.2% of the total mass of PTU, hydroxyl-terminated polydimethylsiloxane, and hydroxy acrylate monomers. Specifically, it can be 0.05 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%; or the range values between any two of the above.

[0034] By introducing siloxane bonds into polythiourethane PTU through a one-pot method and obtaining a hyperbranched polymer with multiple unsaturated double bonds at the end, on the one hand, it can improve the chain growth rate of acrylate during curing, thereby increasing the photocuring rate; on the other hand, the hyperbranched three-dimensional structure enables a large number of cavities and free volumes inside the polymer. When free radical polymerization occurs, it helps to reduce the volume shrinkage of the system, lower the internal stress, and endow the material with good toughness while having relatively high hardness.

[0035] The present invention provides a low-viscosity and high-crosslinking hyperbranched polyurethane acrylate, which is prepared by the preparation method described in the above technical solution.

[0036] In one specific embodiment of the present invention, the structure is as shown in Formula III:

[0037]

[0038] The present invention provides a UV-curable non-metallic knife line die, which comprises the following components in parts by weight:

[0039] 40 - 60 parts of the low-viscosity and high-crosslinking hyperbranched polyurethane acrylate described in the above technical solution;

[0040] 30 - 60 parts of active diluent;

[0041] 2 - 5 parts of photoinitiator.

[0042] The UV-curable non-metallic knife wire mold provided by the present invention comprises 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts of a low-viscosity and high-crosslinking hyperbranched polyurethane acrylate; or a range value between any two of the above.

[0043] The present invention has already clearly described the above-mentioned low-viscosity and high-crosslinking hyperbranched polyurethane acrylate, and will not be elaborated herein.

[0044] The UV-curable non-metallic knife wire mold provided by the present invention comprises 30 - 60 parts of an active diluent; including 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or 60 parts; or a range value between any two of the above.

[0045] According to the present invention, the active diluent comprises one or several of a monofunctional monomer, a difunctional monomer or a trifunctional monomer;

[0046] The monofunctional monomer comprises isobornyl acrylate, isobornyl methacrylate or trimethylolpropane formal acrylate; the difunctional monomer comprises tricyclodecane dimethanol diacrylate or ethylene glycol dimethacrylate; the trifunctional monomer comprises tris(2-hydroxyethyl)isocyanurate triacrylate or trimethylolpropane triacrylate.

[0047] The UV-curable non-metallic knife wire mold provided by the present invention comprises 2 - 5 parts of a photoinitiator; specifically, it can be 2 parts, 3 parts, 4 parts or 5 parts. Or a range value between any two of the above.

[0048] The photoinitiator comprises any one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone and the compounding of the above.

[0049] The present invention provides a preparation method of a UV-curable non-metallic knife wire mold, comprising:

[0050] Blending the low-viscosity and high-crosslinking hyperbranched polyurethane acrylate, the active diluent and the photoinitiator described in the above technical solution, and removing bubbles; then pouring it into the engraved wire groove and sealing it with a substrate, and demolding by light irradiation to obtain it.

[0051] Blend the above components at room temperature for 20 - 60 min to make them completely and uniformly mixed, transfer them to a vacuum oven at -0.8 - -0.9 MPa to remove bubbles for 10 - 30 min, finally pour it into the engraved wire groove and seal it with a substrate, and demold after irradiating with a 1 kW mercury lamp for 1 min to obtain the non-metallic knife wire mold.

[0052] The present invention provides a low-viscosity and highly crosslinked hyperbranched polymer, its preparation method and applications. The product of the present invention not only greatly reduces the internal stress of the system, avoids the volume shrinkage phenomenon after curing, and enhances the adhesion ability to the substrate; at the same time, the terminal groups of the obtained hyperbranched polymer are adjustable, with low viscosity, and can replace or partially replace volatile reactive diluents, greatly reducing the VOC emissions and promoting the green development of photocurable polymers; on the other hand, the organosilicon monomers introduced into the hyperbranched polymer system endow the photocurable resin with a certain deflection, combining polymer materials, structural design and injection molding technology, and improving the universality of the photocurable resin for the application of preparing non-metal knife line molds.

[0053] The hyperbranched topological structure of the present invention significantly reduces the viscosity of the system, improves the leveling performance of the resin, and is more conducive to the coating of the cured resin; on the other hand, it can avoid volume shrinkage after curing, thereby enhancing the adhesion to the substrate. The multiple unsaturated double bonds at the ends of the hyperbranched polymer can increase the crosslinking density of the non-metal knife line mold, and thus obtain better curing rate and mechanical properties. The present invention introduces organosilicon monomers to improve the toughness and impact resistance of the photocurable resin, and avoid the non-metal knife line from falling off the substrate during use due to continuous stamping. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is the GPC molecular weight tracer diagram of the polythiourethane prepared in Examples 1 and 4.

[0055] Figure 2 It is the 1H NMR spectrum diagram of the polythiourethane PTU-1 prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0056] The present invention provides a low-viscosity and highly crosslinked hyperbranched polyurethane acrylate, its preparation method and a UV-curable non-metal knife line mold. Those skilled in the art can draw on the content of this article and appropriately modify the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they all fall within the protection scope of the present invention. The methods and applications of the present invention have been described through preferred embodiments, and those related can obviously make changes or appropriate changes and combinations to the methods and applications in this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0057] It should be understood that the expression "one or more of..." individually includes each object recited after the expression and various different combinations of two or more of the recited objects, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited objects should be understood to have the same meaning, unless otherwise understood from the context.

[0058] The terms "comprising", "having" or "including", including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, without excluding other unrecited elements or steps, unless specifically stated otherwise or understood from the context otherwise.

[0059] In this application, the term "and / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural.

[0060] It should be understood that as long as the present invention is still operable, the order of steps or the order of performing certain actions is not important. In addition, two or more steps or actions can be performed simultaneously.

[0061] The use of any and all examples or exemplary language in this document, such as "for example" or "including", is only intended to better illustrate the present invention and does not limit the scope of the present invention unless a claim is made. No language in this specification should be construed as indicating that any unclaimed element is essential for the practice of the present invention.

[0062] In addition, the numerical ranges and parameters used to define the present invention are approximate values. The relevant values in the specific embodiments have been presented as precisely as possible here. However, any value inherently inevitably contains standard deviations due to individual testing methods. Therefore, unless otherwise clearly stated, it should be understood that all ranges, quantities, values and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0063] It should be understood that in various embodiments of this application, the magnitude of the serial numbers of the above processes does not mean the sequence of execution. Some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic and should not constitute any limitation to the implementation process of the embodiments of this application.

[0064] Some cases are recorded in the embodiments and comparative examples of the present invention, and some implementation manners of the present invention are shown in the embodiments. However, this does not mean that the effects of the present invention can only be achieved in these cases.

[0065] To further illustrate the present invention, a low-viscosity, highly crosslinked hyperbranched polyurethane acrylate, its preparation method, and a UV-curable non-metallic knife line mold provided by the present invention are described in detail below in conjunction with embodiments.

[0066] Embodiments

[0067] Prepare a low-viscosity organosilicon-modified hyperbranched polyurethane acrylate according to the feeding ratios shown in Table 1 and Table 2. The steps are as follows:

[0068] (1) Trimethylolpropane tris(3-mercaptopropionate) (TMPTA) is used as a thiol and reacts with a diisocyanate of isophorone diisocyanate (IPDI) or toluene diisocyanate (TDI). Triethylamine (TEA) is used as a catalyst, and 50 ml of toluene (TL) is used as a solvent. The reaction is carried out at 20 °C for 4 h, and polythiourethane PTU is obtained through rotary evaporation and vacuum drying.

[0069] (2) Add the above PTU to hydroxyl-terminated polydimethylsiloxane (PDMS-OH) (Mn = 1000), mechanically stir for 20 min, then disperse and shear for 10 min with a cell crusher, and transfer it to a flask equipped with a mechanical stirrer, a condensing device, and a nitrogen device. A mixed solution of hydroxyethyl acrylate (HEA) or pentaerythritol triacrylate (PETA), dibutyltin dilaurate (DBTL) as a catalyst (0.1 wt%), and hydroquinone (HQ) as an inhibitor (0.1 wt%) is added to the reaction system by injection at a rate of 6 ml / h. After the injection is completed, the reaction is carried out at 50 °C for 8 h to obtain the product organosilicon-modified hyperbranched polymer Si-HBP-(a-d). The whole reaction process needs to be carried out under a nitrogen atmosphere.

[0070] Mix 40 parts by mass of the organosilicon-modified hyperbranched polymer PTU, 57 parts by mass of isobornyl acrylate, and 3 parts by mass of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, blend at room temperature and 1500 rpm for 30 min, then transfer it to a vacuum oven at -0.9 MPa to remove bubbles for 10 min. Finally, pour it into the engraved wire groove and seal it with a substrate, and demold it after irradiating with a 1 kW mercury lamp for 1 min to obtain a non-metallic knife wire mold.

[0071] Table 1 Polythiourethane PTU synthesis formula table

[0072]

[0073] Table 2 Organosilicon-modified hyperbranched polyurethane acrylate synthesis formula table

[0074]

[0075]

[0076] Figure 1 It is the GPC molecular weight tracer diagram of the polythiourethane prepared in Examples 1 and 4. Among them, the molecular weight Mw of PTU-1 is 44668, and the PDI is 1.55. The molecular weight of PTU-4 is 51487, and the PDI is 1.56. Figure 21H NMR spectrum of the polythiourethane PTU-1 prepared in Example 1 shows a methylene proton signal adjacent to the sulfur atom at 3.6 - 3.7 ppm; the chemical shift at 8.0 - 8.2 ppm is attributed to the carbamoyl group adjacent to the sulfur atom, indicating that after the thiol-isocyanate click reaction, the isocyanate group was successfully introduced into PTU.

[0077] Comparative Example 1

[0078] According to the formulation in Table 1, under nitrogen protection, trimethylolpropane tris(3-mercaptopropionate) (TMPTA), isophorone diisocyanate (IPDI), and triethylamine (TEA) were added to 50 ml of toluene, and the mixture was reacted at 20 °C for 4 h. Then, the product was obtained by rotary evaporation and vacuum drying to get polythiourethane PTU-1. According to the formulation in Table 2, the above PTU-1 was added to a mixture of hydroxyethyl acrylate (HEA), dibutyltin dilaurate (0.1 wt%), and hydroquinone (0.1 wt%). After mechanical stirring for 20 min and then dispersion and shearing by a cell disruptor for 10 min, the mixture was transferred to a flask equipped with a mechanical stirrer, a condensation device, and a nitrogen device, and reacted at 50 °C for 8 h to obtain the product hyperbranched polymer HBP-e. 40 parts by mass of the hyperbranched polymer HBP-e, 57 parts by mass of isobornyl acrylate, and 3 parts by mass of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide were mixed, and the mixture was blended at room temperature and 1500 rpm for 30 min, then transferred to a vacuum oven at -0.9 MPa to defoam for 10 min. Finally, it was poured into the pre-carved wire grooves and sealed with a substrate, and demolded after irradiating with 1 kW mercury lamp for 1 min to obtain a non-metallic knife wire mold.

[0079] Comparative Example 2

[0080] 40 parts by mass of commercially available polyurethane acrylate (specific grade such as: BRC-843D, BOMAR), 57 parts by mass of isobornyl acrylate, and 3 parts by mass of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide were mixed, and the mixture was blended at room temperature and 1500 rpm for 30 min, then transferred to a vacuum oven at -0.9 MPa to defoam for 10 min. Finally, it was poured into the pre-carved wire grooves and sealed with a substrate, and demolded after irradiating with 1 kW mercury lamp for 1 min to obtain a non-metallic knife wire mold.

[0081] Verification Example

[0082] Test Standards for the Properties of Photocurable Resins

[0083] (1) Gel Fraction

[0084] After the organosilicon-modified hyperbranched polymer was photocured into a film, the initial mass was recorded. It was immersed in acetone for 30 minutes, dried, and accurately weighed and recorded. The gel fraction was calculated by the following formula:

[0085]

[0086] Where: W1: film weight before immersion, g; W2: film weight after immersion, g.

[0087] (2) Viscosity

[0088] Test according to the standard of GB / T 10247-2008.

[0089] (3) Exposure time

[0090] Test with a single ultraviolet lamp, the roller coating amount is (15-25) g / m 2 , and the irradiation energy is 1000 mJ / cm 2 . The curing performance is carried out according to the standard of GB / T1728-2020, and the evaluation is carried out by method A (pressing filter paper method) in 7.3.1.

[0091] (4) Adhesion

[0092] Test according to the standard of GB / T 9286-2021. Use a single-edge tool to cut 3 channels along the parallel and perpendicular directions of the long side of the sample, with an interval of 5 mm between each channel and a grid number of 4 grids, and then use 3M tape for peeling test.

[0093] (5) Impact resistance

[0094] Test according to the standard of GB / T 1732-2020.

[0095] (6) Hardness

[0096] Test according to the standard of GB / T 2411-2008.

[0097] Table 3

[0098]

[0099]

[0100] As can be seen from Tables 2 and 3, the present invention prepared Examples 5-8 and Comparative Examples 1-2 by using diisocyanate and acrylate to regulate the skeleton of the organosilicon-modified hyperbranched polymer, thereby proving the universality of the thiol-isocyanate click polymerization for the one-pot preparation of organosilicon-modified hyperbranched polymers. Compared with the properties of the photocuring resins of Comparative Examples 1 and 2, the organosilicon-modified hyperbranched polymer composite photocuring resin prepared in Examples 5-8 of the present invention has a shorter exposure time, the adhesion grade is improved from Grade 2 to Grade 0, and the gel fraction is increased, indicating that the flexible chains of the polymer after organosilicon modification are longer. In addition to the network structure formed by double bond addition, entanglement of polymer chains may also occur, and the curing crosslinking under light is more obvious, thus forming a denser three-dimensional network interpenetrating structure, increasing the toughness and hardness, and therefore obtaining higher impact resistance.

[0101] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a low-viscosity and high-crosslinked hyperbranched polyurethane acrylate, characterized in that, It includes the following steps: A) Dissolve thiol, diisocyanate, and catalyst in a solvent. Under an inert gas environment, use thiol-isocyanate click polymerization reaction to obtain polythiourethane PTU; B) Mix the above-mentioned polythiourethane PTU and hydroxyl-terminated polydimethylsiloxane, stir, and then add a mixed solution of hydroxyacrylate monomer, catalyst, and inhibitor. After the polymerization reaction, it is obtained.

2. The preparation method according to claim 1, wherein The diisocyanate described in step A) is one of isophorone diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, trimethylhexane diisocyanate, 4,4'-diisocyanate dicyclohexylmethane; The thiol is trimethylolpropane tris(3-mercaptopropionate); The molar ratio of the diisocyanate to the thiol is (1-4):(2-1).

3. The preparation method according to claim 1, characterized in that, The catalyst described in step A) is triethylamine, and the catalyst dosage is 0.05-0.2% of the total mass of the diisocyanate and the thiol; The solvent is toluene, tetrahydrofuran, N,N-dimethylformamide, 1,4-dioxane.

4. The preparation method according to claim 1, characterized in that, The hydroxyacrylate monomer described in step B) includes one of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, or pentaerythritol triacrylate; 5. The preparation method according to claim 1, characterized in that, The molecular weight of the hydroxyl-terminated polydimethylsiloxane is 500-2000; The molar ratio of polythiourethane PTU to hydroxyl-terminated polydimethylsiloxane and hydroxyacrylate monomer is 1:(5-20):(10-30).

6. The preparation method according to claim 1, wherein The catalyst is dibutyltin dilaurate or triethylamine, and its dosage is 0.05-0.2% of the total mass of PTU, hydroxyl-terminated polydimethylsiloxane, and hydroxyacrylate monomer; The inhibitor is hydroquinone, and its dosage is 0.05-0.2% of the total mass of PTU, hydroxyl-terminated polydimethylsiloxane, and hydroxyacrylate monomer.

7. A low-viscosity and highly crosslinked hyperbranched polyurethane acrylate, characterized in that, It is prepared by the preparation method described in any one of claims 1-6.

8. A UV-curable non-metallic knife wire die, characterized in that, It includes the following components in parts by weight: 40-60 parts of the low-viscosity high-crosslinked hyperbranched polyurethane acrylate described in claim 7; 30-60 parts of active diluent; 2-5 parts of photoinitiator.

9. The UV-curing non-metallic knife wire die according to claim 8, characterized in that, The active diluent includes one or several of monofunctional monomers, difunctional monomers, or trifunctional monomers; The monofunctional monomer includes isobornyl acrylate, isobornyl methacrylate, or trimethylolpropane formal acrylate; the difunctional monomer includes tricyclodecane dimethanol diacrylate or ethylene glycol dimethacrylate; the trifunctional monomer includes tris(2-hydroxyethyl) isocyanurate triacrylate or trimethylolpropane triacrylate; The photoinitiator includes any one of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone and the above-mentioned blends.

10. A preparation method of a UV-curable non-metallic knife wire die, characterized in that, It includes: Blend the low-viscosity high-crosslinked hyperbranched polyurethane acrylate, active diluent, and photoinitiator described in claim 7, and remove bubbles; Then pour it into the engraved wire groove and seal it with a substrate, and demold it by light irradiation to obtain it.

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