Light-cured polyurethane resin as well as preparation method and application thereof

Abstract

The invention relates to light-cured polyurethane resin as well as a preparation method and application thereof, and belongs to the technical field of polyurethane materials. The preparation raw materials of the light-cured polyurethane resin comprise a photosensitive type light-cured monomer and a polyurethane prepolymer; the specific preparation method of the photosensitive photocuring monomer comprises the following steps: mixing acrylic acid, glycidyl acrylate, a catalyst A and a polymerization inhibitor, and reacting at 100-110 DEG C for 3-6 hours to obtain the photosensitive photocuring monomer, the molar ratio of the acrylic acid to the glycidyl acrylate is (1.02-1.05): 1. The light-cured polyurethane resin provided by the invention has good light-curing activity, the preparation efficiency of the damping material can be greatly improved, and the prepared light-cured polyurethane material is narrow in molecular weight, low in internal heat production in the use process and capable of effectively prolonging the damping service life.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane materials, and in particular to a photocurable polyurethane resin and a preparation method and application thereof. Background Art

[0002] Shock absorption has important uses in household items, mechanical equipment, railway tracks, bridges, aerospace, etc. Shock-absorbing materials are mainly used to absorb and reduce vibrations, which can improve the operating stability and service life of the equipment, thereby achieving a good shock absorption effect. In actual application, shock-absorbing materials require long-term high-intensity vibration wear and tensile compression, which will generate a certain amount of heat during long-term fatigue movement. When the heat reaches a certain temperature, further wear will cause irreversible deformation, and continuous accumulation will cause damage to the shock-absorbing material, thereby reducing its service life and requiring timely replacement, which will affect work efficiency and increase economic costs.

[0003] Polyurethane materials are lightweight, environmentally friendly, have better temperature stability, impact resistance and wear resistance, and polyurethane shock-absorbing materials have attracted more and more attention. However, the existing polyurethane shock-absorbing materials still have the problem of obvious decline in shock-absorbing effect after long-term use.

[0004] In addition, most of the commonly used shock-absorbing materials on the market are mainly heat-cured, with a preparation time of 16-24 hours in most cases, and a few also require a process of more than 4 hours, and the site turnover space is also large. The choice of light curing can significantly improve production efficiency.

[0005] Therefore, it is of great significance to provide a light-cured vibration-absorbing polyurethane material with a long vibration-absorbing life. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a photocurable polyurethane resin and a preparation method and application thereof. The photocurable polyurethane resin has good photocuring activity, can greatly improve the preparation efficiency of shock-absorbing materials, and the prepared photocurable polyurethane material has a narrow molecular weight, and during use, the internal heat generation is low, which can effectively enhance its shock-absorbing life.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a photocurable polyurethane resin, wherein the raw materials for preparing the photocurable polyurethane resin include a photosensitive photocurable monomer and a polyurethane prepolymer;

[0009] The specific preparation method of the photosensitive photocurable monomer comprises the following steps:

[0010] Mixing acrylic acid, glycidyl acrylate, catalyst A and polymerization inhibitor, and reacting at 100-110° C. for 3-6 hours to obtain the photosensitive photocurable monomer;

[0011] The molar ratio of acrylic acid to glycidyl acrylate is (1.02-1.05):1;

[0012] Based on the total mass of the acrylic acid and glycidyl acrylate as 100%, the content of the catalyst A is 0.8-1.2%;

[0013] Based on the total mass of the acrylic acid and glycidyl acrylate being 100%, the content of the polymerization inhibitor is 0.05-0.2%.

[0014] The photosensitive photocurable monomer obtained by the reaction of acrylic acid and glycidyl acrylate has a specific bifunctional monohydroxy structure. When combined with a polyurethane prepolymer, the photocurable polyurethane resin has more active vinyl groups in the molecule. The vinyl groups are less affected by steric hindrance, so that the double bonds are fully and effectively utilized during the photocuring process, so that it has strong photocuring activity. While greatly improving the efficiency of shock-absorbing material preparation, it can preferably increase the crosslinking degree to form a network structure, thereby having an excellent shock-absorbing effect. The prepared photocurable polyurethane material has a narrow molecular weight, and during use, the internal heat generation is low, so that it has excellent wear resistance, thereby effectively enhancing its shock-absorbing life; at the same time, it also has a strong buffering effect and excellent impact resistance.

[0015] The molar ratio of acrylic acid to glycidyl acrylate in the present invention is (1.02-1.05):1, wherein (1.02-1.05) can be, for example, 1.02, 1.03, 1.04 or 1.05, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0016] In the present invention, when the molar ratio of acrylic acid to glycidyl acrylate is (1.02-1.05):1, the carboxyl group (-COOH) in acrylic acid and the epoxy group in glycidyl acrylate undergo a ring-opening reaction, thereby obtaining a photosensitive photocurable monomer with a monohydroxy structure and vinyl groups at both ends with low by-products, which is conducive to its full combination with the subsequent polyurethane prepolymer to obtain a photocurable polyurethane resin with excellent shock-absorbing performance. When the molar ratio of acrylic acid to glycidyl acrylate is too high, too much acid remains in the system, which will affect the water resistance of the product and make it easy to hydrolyze; when the molar ratio of the two is too low, the glycidyl acrylate is too high and too many epoxy groups remain, making the product quality unstable, such as the viscosity continues to increase with the increase of the storage time at room temperature.

[0017] In other embodiments, acrylic acid may be replaced by C1-C3 (eg, C1, C2 or C3) alkyl acrylic acid.

[0018] In the specific preparation method of the photosensitive photocurable monomer provided by the present invention, 100-110°C can be 100°C, 101°C, 102°C, 103°C, 104°C, 105°C, 106°C, 107°C, 108°C, 109°C or 110°C, etc.; 3-6 h can be 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h or 6 h, etc.

[0019] In the present invention, based on the total mass of the acrylic acid and glycidyl acrylate as 100%, the content of the catalyst A is 0.8-1.2%, for example, it can be 0.8%, 0.85%, 0.9%, 0.95%, 1%, 1.05%, 1.1%, 1.15% or 1.2%, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0020] In the present invention, based on the total mass of the acrylic acid and glycidyl acrylate as 100%, the content of the polymerization inhibitor is 0.05-0.2%, for example, it can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18% or 0.2%, as well as specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range.

[0021] In the present invention, when the content of the polymerization inhibitor is too low, it may undergo violent polymerization during the preparation process, while when the content is too high, it will not only cause a waste of raw materials, but also reduce the photocuring efficiency and cause insufficient crosslinking, thereby reducing the impact resistance and wear resistance of the obtained polyurethane material, thereby affecting its shock-absorbing life.

[0022] Preferably, the catalyst A comprises any one of tetraethylammonium bromide, tetrabutylammonium bromide, tetrabutylammonium chloride, tetraethylammonium bromide, tetrabutylammonium hydrogen sulfate, benzyltriethylammonium chloride, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride or tetradecyltrimethylammonium chloride, or a combination of at least two thereof.

[0023] Preferably, the polymerization inhibitor comprises p-hydroxyanisole (MEHQ) and / or tert-butyl p-cresol (BHT).

[0024] In the present invention, a photosensitive photocurable monomer having a specific bifunctional monohydroxyl group is prepared by reacting acrylic acid and glycidyl acrylate in a specific ratio, which can make the obtained photocurable polyurethane resin have strong photocuring activity and high light conversion rate. While greatly improving the preparation efficiency of the shock-absorbing material, it can preferably increase the cross-linking degree to form a network structure, thereby increasing its shock-absorbing life and having an excellent shock-absorbing effect.

[0025] Exemplarily, the reaction equation for preparing the photosensitive photocurable monomer in the present invention is shown in Formula I: Formula Ⅰ.

[0026] In the preparation process of the photosensitive photocurable monomer of the present invention, the reaction is stopped when the measured acid value is lower than 5 mgKOH / g, and the obtained photosensitive photocurable monomer has a monohydroxy structure with vinyl groups at both ends (its specific structure is A or B without further investigation).

[0027] In the present invention, the acid value is determined using a conventional acid value determination method. Further, as a preferred technical solution of the present invention, the acid value is determined using an acid-base titration method.

[0028] Preferably, the polyurethane prepolymer is prepared by reacting polyester polyol and isocyanate monomer.

[0029] Preferably, the molar ratio of the isocyanate monomer to the polyester polyol is (1.5-2):1, wherein (1.5-2) can be, for example, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95 or 2, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0030] Preferably, the polyester polyol includes any one of poly(hexane adipate glycol), poly(caprolactone glycol) or poly(butylene adipate glycol) or a combination of at least two thereof; more preferably, it includes any one of poly(hexane adipate glycol 1000), poly(caprolactone glycol) or poly(butylene adipate glycol) or a combination of at least two thereof.

[0031] The present invention further optimizes the polyester polyols and adopts highly crystalline polyester polyols. Structures such as polyhexanediol adipate and polycaprolactone diol have strong crystallinity, which can improve the microphase separation of polyurethane, so that it has a strong buffering effect when resisting external impact, avoiding damage of the obtained polyurethane material under repeated impact and stretching, thereby improving its shock absorbing life.

[0032] Preferably, the polyester polyol needs to be dehydrated before the reaction.

[0033] Preferably, the water removal treatment comprises vacuum water removal at 105-115°C (for example, 106°C, 107°C, 108°C, 109°C, 110°C, 111°C, 112°C, 113°C or 114°C, etc.).

[0034] Preferably, the isocyanate monomer includes any one of toluene diisocyanate (TDI) monomer, diphenylmethane diisocyanate (MDI) monomer or hexamethylene diisocyanate (HDI) monomer or a combination of at least two thereof.

[0035] Preferably, the TDI monomer includes any one of TDI-100, TDI-80 or TDI-65, or a combination of at least two thereof.

[0036] In the present invention, the isocyanate monomer is preferably TDI-100, which has a more regular structure. The polyurethane prepolymer prepared by using it as a raw material has a narrower molecular weight distribution, so that the obtained polyurethane material can have good impact resistance and wear resistance, thereby making its overall technical effect better.

[0037] Preferably, the reaction is carried out in the presence of a catalyst B.

[0038] Preferably, the catalyst B comprises an organotin catalyst.

[0039] Preferably, the organotin catalyst comprises dibutyltin dilaurate (DBTDL) and / or stannous octoate.

[0040] Preferably, based on the total mass of the polyester polyol and the isocyanate monomer as 100%, the content of the catalyst B is 0.05-0.2%, for example, it can be 0.05%, 0.08%, 0.1%, 0.12%, 0.15%, 0.18% or 0.2%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0041] Preferably, the reaction is carried out under a protective gas atmosphere.

[0042] Preferably, the protective gas includes any one of nitrogen, argon or helium, or a combination of at least two of them.

[0043] Preferably, the method for preparing the polyurethane prepolymer specifically comprises the following steps:

[0044] Under the action of catalyst B, polyester polyol is reacted with isocyanate monomer, the reaction temperature is controlled not higher than 35° C., and the reaction is carried out until the hydroxyl value is lower than 5 mgKOH / g to obtain the polyurethane prepolymer.

[0045] In the preparation process of the polyurethane prepolymer of the present invention, a hydroxyl group (-OH) in a polyester polyol and an isocyanate group (-NCO) in an isocyanate monomer are reacted under the action of a catalyst B; further, since the molar ratio of the isocyanate monomer to the polyester polyol is (1.5-2):1, that is, the amount of the isocyanate group is greater than the amount of the hydroxyl group, an isocyanate-terminated polyurethane prepolymer can be obtained.

[0046] Exemplarily, the reaction equation for preparing the polyurethane prepolymer in the present invention is shown in Formula II:

[0047] Formula II.

[0048] In the formula II, " " denotes polyester polyol," " indicates isocyanate," ” indicates polyurethane prepolymer.

[0049] Preferably, before adding the polyester polyol, the reaction temperature is controlled to be no higher than 15°C, more preferably 5-15°C (for example, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C or 15°C, etc.).

[0050] In the present invention, the hydroxyl value is measured by conventional measurement methods in the art, including "GBT 7193.2-1987 Method for Determining Hydroxyl Value of Unsaturated Polyester Resin".

[0051] Preferably, a deionization treatment is performed after the reaction is completed.

[0052] Preferably, the low-ionization treatment specifically includes subjecting the reaction liquid after the reaction to reduced pressure distillation.

[0053] Preferably, the temperature of the reduced pressure distillation is 110-150°C, for example, it can be 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0054] Preferably, the vacuum degree of the reduced pressure distillation is 0.1-2.0 mmHg, for example, it can be 0.1 mmHg, 0.3 mmHg, 0.5 mmHg, 0.8 mmHg, 1 mmHg, 1.2 mmHg, 1.5 mmHg, 1.8 mmHg or 2 mmHg, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0055] Preferably, the time for the reduced pressure distillation is 6-8 h, for example, it can be 6 h, 6.5 h, 7 h, 7.5 h, 8 h or 8.5 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0056] Preferably, the degree of freeness of isocyanate monomer in the polyurethane prepolymer is less than 0.1%.

[0057] In the present invention, the degree of freeness of the isocyanate monomer is measured by using a prepared external standard curve of GC.

[0058] In the preparation process of the polyurethane prepolymer of the present invention, the polyester polyol is reacted with the isocyanate monomer by slowly dripping in batches (it can be divided into 3-8 times, and the specific number of batches and the dripping rate are regulated according to the actual temperature change), and the temperature is regulated by cooling with condensed water during the reaction process, so that the reaction temperature in the entire reaction system does not exceed 35°C. The subsequent vacuum distillation post-treatment method eliminates a small number of low molecular weight products or raw materials that may exist, so that the molecular weight distribution of the polyurethane material structure prepared by it is very narrow. The narrow molecular weight distribution is more isotropic when resisting external impact, reducing internal losses, so that the heat generated internally during use is much lower than that of conventional materials, thereby improving its wear resistance and further enhancing its shock-absorbing life. When the reaction temperature is too high during the preparation of the prepolymer, the molecular weight distribution of the polyurethane material structure prepared by it becomes broad, and during use, the internal heat cannot be well reduced, thereby failing to well extend its shock-absorbing life.

[0059] The common method for preparing low-free prepolymers on the market is mainly based on diaphragm evaporation. The polyurethane prepolymer prepared by this method is relatively convenient, but the preparation cost is extremely high due to the expensive diaphragm evaporator equipment, and the process cost of its preparation is often equivalent to the material cost. In comparison, the low-free polyurethane prepolymer prepared by the low-temperature process combined with reduced pressure distillation provided by the present invention has a low preparation cost, and the dispersion coefficient of the polyurethane prepolymer prepared by the diaphragm evaporation method is much lower than that of the polyurethane prepolymer prepared by the diaphragm evaporation method, which enhances its shock absorption effect.

[0060] In a second aspect, the present invention provides a method for preparing the photocurable polyurethane resin as described in the first aspect, the preparation method comprising the following steps:

[0061] The photosensitive photocurable monomer and the polyurethane prepolymer are mixed and reacted, and the molar ratio of hydroxyl group to NCO is controlled to be 1:1, and the reaction NCO is less than 0.1%, so as to obtain the photocurable polyurethane resin.

[0062] In the preparation process of the photocurable polyurethane resin of the present invention, the isocyanate group in the polyurethane prepolymer reacts with the hydroxyl group in the photosensitive photocurable monomer, and the molar ratio of the hydroxyl group to the NCO group is controlled to be 1:1, so that the hydroxyl group and the isocyanate group react completely to obtain the photocurable polyurethane resin containing the acrylate group.

[0063] Exemplarily, the reaction equation for preparing the photocurable polyurethane resin in the present invention is shown in Formula III:

[0064] Formula III.

[0065] In the formula III, " " indicates polyurethane prepolymer," ” indicates a photosensitive photocurable monomer, ” indicates a light-curing polyurethane resin.

[0066] Preferably, the method for preparing the photocurable polyurethane resin specifically comprises the following steps:

[0067] (1) Preparation of photosensitive photocurable monomers

[0068] Acrylic acid, glycidyl acrylate, catalyst A and polymerization inhibitor are mixed, reacted at 100-110° C. for 3-6 h, and the reaction is stopped when the acid value is lower than 5 mgKOH / g to obtain the photosensitive photocurable monomer.

[0069] (2) Preparation of polyurethane prepolymer

[0070] Under a nitrogen atmosphere, add isocyanate monomer and catalyst B into a reactor, stir and mix, slowly add polyester polyol in batches at 5-15°C, keep the temperature not exceeding 35°C, stop the reaction when the hydroxyl value is lower than 5 mgKOH / g, and distill the reaction solution under reduced pressure at a temperature of 110-150°C and a vacuum degree of 0.1-2.0 mmHg for 6-8 h to obtain a polyurethane prepolymer in which the free degree of isocyanate is lower than 0.1%.

[0071] (3) Mixing the photosensitive photocurable monomer described in step (1) with the polyurethane prepolymer described in step (2), controlling the molar ratio of hydroxyl group to NCO to be 1:1, and reacting them. When the NCO is measured to be less than 0.1%, the photocurable polyurethane resin is obtained.

[0072] In a third aspect, the present invention provides a photocurable polyurethane material, wherein the photocurable polyurethane material comprises the photocurable polyurethane resin described in the first aspect.

[0073] Preferably, the photocurable polyurethane material comprises the following components in parts by weight:

[0074] The photocurable polyurethane resin of the first aspect comprises 60-80 parts by weight, 10-20 parts by weight of a photocurable monomer, 2-8 parts by weight of a photocurable initiator, and 2-5 parts by weight of a filler.

[0075] In the photocurable polyurethane material of the present invention, the content of the photocurable polyurethane resin is 60-80 parts by weight, for example, 60 parts by weight, 62 parts by weight, 65 parts by weight, 68 parts by weight, 70 parts by weight or 80 parts by weight.

[0076] The content of the photocurable monomer is 10-20 parts by weight, for example, it can be 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight, 17 parts by weight, 18 parts by weight, 19 parts by weight or 20 parts by weight, etc.

[0077] The content of the photocuring initiator is 2-8 parts by weight, for example, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight or 8 parts by weight.

[0078] The content of the filler is 2-5 parts by weight, for example, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 3.5 parts by weight, 4 parts by weight, 4.5 parts by weight or 5 parts by weight.

[0079] Preferably, the photocurable monomer described in the present invention is a conventional difunctional monomer or trifunctional monomer in the art, including but not limited to any one or a combination of at least two of hexanediol diacrylate (HDDA), neopentyl glycol diacrylate (NPGDA) or trimethylolpropane triacrylate (TMPTA).

[0080] Preferably, the photocuring initiator of the present invention is a conventional product in the art, including but not limited to any one of photoinitiator 819, photoinitiator 1173, photoinitiator TPO or photoinitiator 184, or a combination of at least two thereof.

[0081] Preferably, the filler comprises carbon black.

[0082] Exemplarily, the method for preparing the photocurable polyurethane material provided by the present invention comprises the following steps:

[0083] The photocurable polyurethane resin, the photocurable monomer, the photocurable initiator and the filler are mixed and photocured under ultraviolet light to obtain the photocurable polyurethane material.

[0084] Preferably, the exposure wavelength of the ultraviolet light is 365-380 nm, for example, it can be 365 nm, 368 nm, 370 nm, 372 nm, 375 nm, 378 nm or 380 nm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0085] Preferably, the exposure energy of the ultraviolet light is 400-500 mJ / cm 2 , for example, 400 mJ / cm 2 、410mJ / cm 2 , 420 mJ / cm 2 、430 mJ / cm 2 , 440 mJ / cm 2 , 450 mJ / cm 2 , 460 mJ / cm 2 , 470 mJ / cm 2 、480mJ / cm 2 , 490 mJ / cm 2 or 500 mJ / cm 2 , as well as specific point values ​​between the above point values, due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0086] The present invention sets a limit on the exposure energy. When the exposure energy is higher than this range, the brittleness of the obtained polyurethane material increases and the shock absorbing effect decreases.

[0087] The present invention uses a polyurethane resin prepared from a photosensitive photocurable monomer with a specific double-photon energy group single-hydroxy structure as a raw material to prepare a polyurethane material, which has a strong photocuring activity. Since most shock-absorbing materials are added with certain fillers, such as color-distinguishing toner, carbon black, pigments, etc., or some flame-retardant materials, such as flame retardants, or a certain amount of thermal conductive materials, such as micron-level aluminum oxide, aluminum nitride, boron nitride, etc., these materials will affect ultraviolet light and reduce the photocuring activity of the obtained polyurethane material. The polyurethane material of the present invention uses a self-made photosensitive photocurable monomer to compensate for the dilution of light by the filler as much as possible, thereby greatly improving the preparation efficiency of the obtained polyurethane material.

[0088] In a fourth aspect, the present invention provides a use of the photocurable polyurethane material as described in the third aspect in automobiles and buildings.

[0089] The light-curing polyurethane material provided by the present invention can be well applied to gaskets in various links of automobile shock absorption, thereby making them have a longer shock absorption life.

[0090] Compared with the prior art, the present invention has at least the following beneficial effects:

[0091] The photosensitive photocurable monomer obtained by the reaction of acrylic acid and glycidyl acrylate of the present invention has a specific bifunctional monohydroxy structure, which can make the obtained photocurable polyurethane resin have strong photocuring activity, greatly improve the efficiency of preparing shock-absorbing materials, and improve the degree of crosslinking, thereby having an excellent shock-absorbing effect. Furthermore, the photocurable polyurethane material prepared by the photocurable polyurethane resin provided by the present invention has a narrow molecular weight, and during use, the internal heat generation is low, thereby effectively improving its wear resistance and thereby enhancing its shock-absorbing life; at the same time, it also has a strong buffering effect and excellent impact resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 is the infrared spectrum of the photosensitive photocurable monomer obtained in Example 1;

[0093] Figure 2 is the infrared spectrum of the polyurethane prepolymer obtained in Example 1;

[0094] Figure 3 is the infrared spectrum of the photocurable polyurethane resin obtained in Example 1. DETAILED DESCRIPTION

[0095] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0096] Unless otherwise specified, the raw materials and reagents used in the following examples, comparative examples and application examples are commercially available. Information on some raw materials is as follows:

[0097] Poly(hexanediol adipate) 1000: purchased from Shandong Jining Huakai Resin HK-5112;

[0098] Polycaprolactone diol 1000: purchased from Hunan Juren PCL1000;

[0099] Polybutylene adipate 1000: purchased from Zhejiang Huafeng PE-T3010;

[0100] Carbon black: purchased from Cabot MONARCH 1400.

[0101] Example 1

[0102] This embodiment provides a photocurable polyurethane resin, and the preparation method thereof comprises the following steps:

[0103] (1) Preparation of photosensitive photocurable monomers

[0104] Acrylic acid (1.05 mol), glycidyl acrylate (1 mol), tetraethylammonium bromide (2 g) and inhibitor MEHQ (0.15 g) were mixed and reacted at 105° C. for 4.5 h, with an acid value of 3.3 mgKOH / g, to obtain the photosensitive photocurable monomer.

[0105] The obtained photosensitive photocurable monomer was tested by infrared spectrum, and the test results are as follows: Figure 1 As shown, at a wave number of 3550 cm -1 A higher characteristic absorption peak of alcoholic hydroxyl group appeared at 1710 cm -1 The characteristic absorption peak of carbonyl is at 1620 cm -1 、1400cm -1 The characteristic absorption peak at indicates the presence of a double bond.

[0106] (2) Preparation of polyurethane prepolymer

[0107] Under a nitrogen atmosphere, TDI-100 monomer (2 mol) and dibutyltin dilaurate (0.7 g) were added into the reactor and stirred to mix. At 10°C, poly(hexanediol adipate) 1000 (1 mol) was slowly added dropwise in four portions. The temperature was kept not higher than 35°C. The reaction was stopped when the hydroxyl value was lower than 5 mgKOH / g. The reaction solution was distilled under reduced pressure at 130°C and a vacuum degree of 1.0 mmHg for 7 h to obtain a polyurethane prepolymer in which the free degree of TDI-100 was 0.08%.

[0108] The obtained polyurethane prepolymer was subjected to infrared spectrum test, and the test results were as follows: Figure 2 As shown, at a wave number of 3500 cm -1 There is no higher characteristic absorption peak of alcoholic hydroxyl group at 3250cm -1 The characteristic absorption peak of NH appeared at 2260 cm -1 There is an obvious characteristic absorption peak of NCO at , indicating that the hydroxyl group in the polyester polyol reacts with the isocyanate monomer to form an NCO-terminated prepolymer.

[0109] (3) Mixing the photosensitive photocurable monomer described in step (1) with the polyurethane prepolymer described in step (2), controlling the molar ratio of hydroxyl group to NCO to be 1:1, and reacting them. When the NCO is measured to be less than 0.1%, the photocurable polyurethane resin is obtained.

[0110] The obtained light-cured polyurethane resin was subjected to infrared spectrum test, and the test results are as follows: Figure 3 As shown, Figure 2 In comparison, the characteristic absorption peak of NCO is 2260 cm-1 The obvious disappearance of the isocyanate group in the polyurethane prepolymer and the hydroxyl group in the photosensitive photocurable monomer reacted.

[0111] Example 2

[0112] This embodiment provides a photocurable polyurethane resin, and the preparation method thereof comprises the following steps:

[0113] (1) Preparation of photosensitive photocurable monomers

[0114] Acrylic acid (1.02 mol), glycidyl acrylate (1 mol), tetrabutylammonium bromide (2 g) and inhibitor BHT (0.2 g) were mixed and reacted at 110° C. for 3 h. The acid value was 4.2 mgKOH / g to obtain the photosensitive photocurable monomer.

[0115] (2) Preparation of polyurethane prepolymer

[0116] Under a nitrogen atmosphere, TDI-100 monomer (2 mol) and dibutyltin dilaurate (1.4 g) were added into the reactor and stirred to mix. At 15°C, polycaprolactone diol 1000 (1 mol) was slowly added dropwise in three times. The temperature was kept not higher than 35°C. The reaction was stopped when the hydroxyl value was lower than 5 mgKOH / g. The reaction solution was distilled under reduced pressure at 110°C and a vacuum degree of 0.1 mmHg for 8 h to obtain a polyurethane prepolymer with a TDI-100 freeness of 0.08%.

[0117] (3) Mixing the photosensitive photocurable monomer described in step (1) with the polyurethane prepolymer described in step (2), controlling the molar ratio of hydroxyl group to NCO to be 1:1, and reacting them. When the NCO is measured to be less than 0.1%, the photocurable polyurethane resin is obtained.

[0118] Example 3

[0119] This embodiment provides a photocurable polyurethane resin, and the preparation method thereof comprises the following steps:

[0120] (1) Preparation of photosensitive photocurable monomers

[0121] Acrylic acid (1 mol), glycidyl acrylate (1 mol), tetraethylammonium bromide (2.2 g) and inhibitor MEHQ (0.2 g) were mixed and reacted at 100° C. for 6 h, with an acid value of 4.4 mgKOH / g, to obtain the photosensitive photocurable monomer.

[0122] (2) Preparation of polyurethane prepolymer

[0123] Under a nitrogen atmosphere, TDI-100 monomer (3 mol) and dibutyltin dilaurate (5 g) were added into the reactor and stirred to mix. At 5°C, polybutylene adipate 1000 (2 mol) was slowly added dropwise in five times. The temperature was kept not higher than 35°C. The reaction was stopped when the hydroxyl value was lower than 5 mgKOH / g. The reaction solution was distilled under reduced pressure at 150°C and a vacuum degree of 2.0 mmHg for 6 h to obtain a polyurethane prepolymer with a TDI-100 freeness of 0.07%.

[0124] (3) Mixing the photosensitive photocurable monomer described in step (1) with the polyurethane prepolymer described in step (2), controlling the molar ratio of hydroxyl group to NCO to be 1:1, and reacting them. When the NCO is measured to be less than 0.1%, the photocurable polyurethane resin is obtained.

[0125] Example 4

[0126] This embodiment provides a photocurable polyurethane resin, which differs from Embodiment 1 in that the poly(hexanediol adipate) 1000 in step (2) is replaced by an equimolar amount of poly(neopentyl phthalate) 1000 (purchased from Zhejiang Huafeng HF-8211), and other raw materials, contents and preparation methods are the same as those in Embodiment 1.

[0127] Example 5

[0128] This embodiment provides a photocurable polyurethane resin, which differs from Embodiment 1 in that the temperature in step (2) is maintained at 50±3° C., and other raw materials, contents and preparation methods are the same as those in Embodiment 1.

[0129] Example 6

[0130] This embodiment provides a photocurable polyurethane resin, which differs from Embodiment 1 in that the TDI-100 monomer in step (2) is replaced by an equal mass of TDI-80, and other raw materials, contents and preparation methods are the same as those in Embodiment 1.

[0131] Example 7

[0132] This embodiment provides a photocurable polyurethane resin, which differs from Embodiment 1 in that the TDI-100 monomer in step (2) is replaced by an equal mass of TDI-65, and other raw materials, contents and preparation methods are the same as those in Embodiment 1.

[0133] Example 8

[0134] This embodiment provides a photocurable polyurethane resin, which differs from Embodiment 1 in that the content of the polymerization inhibitor MEHQ in step (1) is adjusted from 0.15 g to 0.6 g, and other raw materials, contents and preparation methods are the same as those in Embodiment 1.

[0135] Comparative Example 1

[0136] This comparative example provides a photocurable polyurethane resin, which differs from Example 1 in that the photosensitive photocurable monomer is replaced with 2-hydroxyethyl acrylate (HEA), and other raw materials, contents and preparation methods are the same as those in Example 1.

[0137] Application Example 1

[0138] This application example provides a photocurable polyurethane material, the preparation method of which includes the following steps:

[0139] 70 parts by weight of photocurable polyurethane resin (Example 1), 15 parts by weight of photocurable monomer HDDA, 5 parts by weight of photoinitiator 1173, and 3.5 parts by weight of carbon black were mixed to obtain a mixed solution, and the mixed solution was introduced into a material tank with a mold of 100*100*3 mm for exposure at an exposure wavelength of 365-380 nm and an exposure energy of 400-500 mJ / cm 2 The polyurethane material is photocured under light to obtain the photocurable polyurethane material.

[0140] Application Example 2

[0141] This application example provides a photocurable polyurethane material, the preparation method of which includes the following steps:

[0142] 60 parts by weight of photocurable polyurethane resin (Example 1), 10 parts by weight of photocurable monomer NPGDA, 2 parts by weight of photoinitiator 184, and 2 parts by weight of carbon black were mixed to obtain a mixed solution, and the mixed solution was introduced into a material tank with a mold of 100*100*3mm for exposure at an exposure wavelength of 365-380 nm and an exposure energy of 400-500 mJ / cm 2 The polyurethane material is photocured under light to obtain the photocurable polyurethane material.

[0143] Application Example 3

[0144] This application example provides a photocurable polyurethane material, the preparation method of which includes the following steps:

[0145] 80 parts by weight of photocurable polyurethane resin (Example 1), 20 parts by weight of photocurable monomer TMPTA, 8 parts by weight of photoinitiator 819, and 5 parts by weight of carbon black were mixed to obtain a mixed solution, and the mixed solution was introduced into a material tank with a mold of 100*100*3mm for exposure at an exposure wavelength of 365-380 nm and an exposure energy of 400-500 mJ / cm2 The polyurethane material is photocured under light to obtain the photocurable polyurethane material.

[0146] Application Example 4-10

[0147] The difference between Application Examples 4-10 and Application Example 1 is that the photocurable polyurethane resin (Example 1) in Application Example 1 is replaced with an equal mass of photocurable polyurethane resin (Examples 2-8), and the other components, contents and preparation methods are the same as those in Application Example 1.

[0148] Comparative application example 1

[0149] This comparative application example 1 provides a photocurable polyurethane material, which differs from application example 1 in that the photocurable polyurethane resin (Example 1) in application example 1 is replaced by a photocurable polyurethane resin (Comparative Example 1) of equal mass, and other components, contents and preparation methods are the same as those in application example 1.

[0150] The above application examples 1-10 and comparative application example 1 were subjected to performance tests, and the test methods / standards are as follows:

[0151] (1) Impact resistance: Refer to GB / T 39814-2021, use a 50 g metal ball to test the crack height (mm) when the ball falls at the center;

[0152] (2) Wear resistance: Using Taber abrasion machine, roller CS-10, set 500 g load, 60 rpm, and test the wear results after 200 turns:

[0153] Wear index = loss mass / 200*1000 (mg);

[0154] (3) Photocuring efficiency (%): Refer to GB / T 6040-2019, the characteristic absorption peak is 1380-1420 cm -1 Double bond peak, reference peak selected 1656-1730 cm -1 Near the carbonyl peak, the test sample before curing is mixed, and the test sample after curing is selected as a sample. The test surface of the sample must be cleaned with alcohol before pressing and testing infrared.

[0155] The test results are shown in Table 1.

[0156] Table 1

[0157]

[0158] The test results show that:

[0159] (1) It can be seen from Application Examples 1 to 10 that when the photocurable polyurethane resin prepared by reacting a specific photosensitive polyurethane monomer with a polyurethane prepolymer is applied to a photocurable polyurethane material, it can obtain excellent photocuring efficiency (65.44-80.16%), high impact resistance (crack height not less than 200 mm) and high wear resistance, and the comprehensive effect is excellent, thereby effectively improving its shock absorption life and making it have excellent shock absorption effect.

[0160] (2) By comparing Application Example 1 with Application Example 6, it can be seen that Application Example 6 uses a specific polyester polyol that is not of the present invention, and the impact resistance and wear resistance of the resulting photocurable polyurethane material are significantly reduced, indicating that the present invention further selects and optimizes the polyurethane polyol in the preparation process of the photocurable polyurethane resin, so that the obtained polyurethane resin has better impact resistance and wear resistance when used in the photocurable polyurethane material, thereby effectively improving its shock absorbing life and making it have better shock absorbing effect.

[0161] (3) By comparing Application Example 1 with Application Example 7, it can be seen that the process temperature controlled in the preparation process of the polyurethane prepolymer in the photocurable polyurethane resin of Application Example 7 is relatively high, which makes the molecular weight distribution too wide, thereby significantly reducing the impact resistance and wear resistance of the obtained polyurethane material. This shows that the present invention can significantly improve the impact resistance and wear resistance of the obtained polyurethane material by optimizing the process temperature of the polyurethane prepolymer in the preparation process of the photocurable polyurethane resin, thereby improving its shock absorption life and making it have a better shock absorption effect.

[0162] (4) By comparing Application Example 1 with Application Examples 8 and 9, it can be seen that Application Examples 8 and 9 respectively use TDI-80 and TDI-65, both of which have slightly worse regularity than TDI-100, so the molecular weight distribution of the products prepared therefrom is wider, making them slightly worse than Application Example 1 in terms of impact resistance and wear resistance. This shows that the present invention can obtain better comprehensive performance by further optimizing the selection of isocyanate in the preparation process of the photocurable polyurethane resin, thereby improving its shock absorbing life and making it have better shock absorbing effect.

[0163] (5) By comparing Application Example 1 with Application Example 10, it can be seen that in the preparation process of photocurable polyurethane resin, when the content of the inhibitor is too high, the photocuring effect will be reduced, resulting in insufficient crosslinking degree, and the impact resistance and wear resistance will be slightly reduced.

[0164] (6) By comparing Application Example 1 with Comparative Application Example 1, it can be seen that Comparative Application Example 1 uses HEA to replace the specific photosensitive photocurable monomer of the present invention, and its photocuring conversion efficiency is significantly reduced, and the impact resistance and wear resistance are greatly reduced, which cannot well improve the shock absorbing life of the obtained polyurethane material.

[0165] In summary, when the photocurable polyurethane resin prepared by the reaction of a specific photosensitive polyurethane monomer and a polyurethane prepolymer is applied to a photocurable polyurethane material, it can obtain excellent photocuring efficiency, high impact resistance and high wear resistance, thereby effectively improving its shock absorbing life and making it have an excellent shock absorbing effect.

[0166] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention are within the protection scope and disclosure scope of the present invention.

Claims

1. A photocurable polyurethane resin, characterized in that: The raw materials for preparing the photocurable polyurethane resin include photosensitive photocurable monomers and polyurethane prepolymers; The specific preparation method of the photosensitive photocurable monomer comprises the following steps: Mixing acrylic acid, glycidyl acrylate, catalyst A and polymerization inhibitor, and reacting at 100-110° C. for 3-6 hours to obtain the photosensitive photocurable monomer; The molar ratio of acrylic acid to glycidyl acrylate is (1.02-1.05):1; Based on the total mass of the acrylic acid and glycidyl acrylate as 100%, the content of the catalyst A is 0.8-1.2%; Based on the total mass of the acrylic acid and glycidyl acrylate being 100%, the content of the polymerization inhibitor is 0.05-0.2%.

2. The photocurable polyurethane resin according to claim 1, characterized in that: The polyurethane prepolymer is prepared by reacting polyester polyol and isocyanate monomer; The molar ratio of the isocyanate monomer to the polyester polyol is (1.5-2):1; The polyester polyol includes any one of poly(hexane adipate glycol), poly(caprolactone glycol) or poly(butylene adipate glycol) or a combination of at least two thereof; The isocyanate monomer includes any one of TDI monomer, MDI monomer or HDI monomer or a combination of at least two; The TDI monomer includes any one of TDI-100, TDI-80 or TDI-65 or a combination of at least two; The reaction is carried out under catalyst B; The catalyst B includes an organic tin catalyst.

3. The photocurable polyurethane resin according to claim 2, characterized in that: The preparation method of the polyurethane prepolymer specifically comprises the following steps: Under the action of catalyst B, polyester polyol is reacted with isocyanate monomer, the reaction temperature is controlled not higher than 35° C., and the reaction is carried out until the hydroxyl value is lower than 5 mgKOH / g to obtain the polyurethane prepolymer.

4. The photocurable polyurethane resin according to claim 3, characterized in that: After the reaction of the polyester polyol and the isocyanate monomer is completed, a low-freeization treatment is performed; The low-freeization treatment specifically includes distilling the reaction liquid under reduced pressure after the reaction is completed; The degree of freeness of the isocyanate monomer in the polyurethane prepolymer is less than 0.1%.

5. A method for preparing a photocurable polyurethane resin according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: The photosensitive photocurable monomer and the polyurethane prepolymer are mixed and reacted, and the molar ratio of hydroxyl group to NCO is controlled to be 1:1, and the reaction NCO is less than 0.1%, so as to obtain the photocurable polyurethane resin.

6. A photocurable polyurethane material, characterized in that: The photocurable polyurethane material comprises the photocurable polyurethane resin according to any one of claims 1 to 4.

7. The photocurable polyurethane material according to claim 6, characterized in that: The photocurable polyurethane material comprises the following components in parts by weight: 60-80 parts by weight of the photocurable polyurethane resin according to any one of claims 1 to 4, 10-20 parts by weight of a photocurable monomer, 2-8 parts by weight of a photocurable initiator, and 2-5 parts by weight of a filler; The photocurable monomer includes any one of HDDA, NPGDA or TMPTA or a combination of at least two thereof; The filler includes carbon black.

8. Use of the photocurable polyurethane material as claimed in claim 6 in automobiles and buildings.

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