Composition capable of being cured and decomposed by ultraviolet light and preparation method thereof

Abstract

The invention discloses a composition capable of being cured and decomposed by ultraviolet light and a preparation method thereof. The composition capable of being cured and decomposed by ultraviolet light comprises modified polyurethane resin, an acrylic monomer, a photoinitiator and an auxiliary agent, the modified polyurethane resin accounts for 70.0-98.8% of the total mass; the acrylic monomer accounts for 0.1-30.0% of the total mass; the photoinitiator accounts for 0.1-5.0% of the total mass; and the auxiliary agent accounts for 1.0-10.0% of the total mass. According to the invention, curing and decomposition can be realized under ultraviolet light with different wavelengths.

Description

Technical Field

[0001] The invention relates to the field of adhesives, and in particular to a composition capable of being cured and decomposed by ultraviolet light and a preparation method thereof. Background Art

[0002] UV-curable temporary protective glue, according to different applications, mainly has two types: surface protection and temporary fixation. Surface protection refers to applying glue on the surface of the workpiece to be processed to prevent the surface of the workpiece from being damaged during mechanical or chemical processing. Temporary fixation refers to using glue to stick the workpiece to be processed before processing, so that the workpiece does not move during processing and can be accurately processed. In recent years, with the rapid development of the electronics industry, in order to meet different appearance and functional requirements, the processing requirements for workpieces of various materials are becoming higher and higher. UV-curable temporary protective glue has been widely used in this process. After the workpiece processing is completed, the temporary protective glue needs to be removed, generally by tearing it by hand and removing the glue with a detergent.

[0003] The hand-tearing or hand-stripping glue removal process requires that the workpiece to be protected is large in size and the glue has low adhesion to the substrate, otherwise it will be difficult to remove the glue or damage the surface of the workpiece. This method has low production efficiency and is not suitable for small precision parts. The cleaning agent removal method uses two types of cleaning agents: water-based and solvent-based. Most UV-cured temporary protective glues need to be removed by ultrasonic treatment at high temperature using solvent-based cleaning agents, which poses certain safety and environmental risks. UV-curing glue removed using water-based cleaning agents has poor acid and alkali resistance, so it is not suitable for some chemical processing processes with harsh conditions.

[0004] Therefore, it is urgent to provide a composition that can be cured and decomposed by ultraviolet light and a preparation method to solve the above problems. Summary of the invention

[0005] The purpose of the present invention is to provide a composition that can be cured and decomposed by ultraviolet light and a preparation method thereof, which can achieve curing and decomposition under ultraviolet light of different wavelengths.

[0006] In order to solve the above technical problems, the present invention provides a composition that can be cured and decomposed by ultraviolet light, comprising: a modified polyurethane resin, an acrylic monomer, a photoinitiator and an auxiliary agent;

[0007] The modified polyurethane resin accounts for 70.0-98.8% of the total mass; the acrylic monomer accounts for 0.1-30.0% of the total mass; the photoinitiator accounts for 0.1-5.0% of the total mass; and the auxiliary agent accounts for 1.0-10.0% of the total mass.

[0008] Furthermore, the modified polyurethane resin comprises components including: polyol, isocyanate, catalyst and hydroxycoumarin.

[0009] Furthermore, the polyol includes: polyether polyol, polyester polyol, polycarbonate polyol or polybutadiene polyol having a hydroxyl value of 28 to 280 mgKOH / g.

[0010] Further, the isocyanate includes: toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and 1,6-hexamethylene diisocyanate, or a combination of more thereof.

[0011] Furthermore, the catalyst comprises: one or more combinations of organic tin compounds, organic bismuth compounds, organic bismuth zinc compounds and amine compounds.

[0012] Furthermore, the hydroxycoumarin includes: 4-hydroxycoumarin, 4-methyl-7-hydroxycoumarin, 7-hydroxycoumarin, or a combination of more thereof.

[0013] Further, the acrylic monomer includes: hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofuran (meth)acrylate, isooctyl acrylate, isodecyl acrylate, alkoxydodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloylmorpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate and polycaprolactone modified acrylate. One or more combinations thereof.

[0014] Further, the acrylic monomer includes: one or more combinations of isooctyl acrylate, isodecyl acrylate, alkoxydodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloylmorpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate and polycaprolactone modified acrylate.

[0015] Further, the photoinitiator includes: 2-hydroxy-methylphenylpropane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, isopropylthioxanthone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, camphorquinone and one or more of ethyl 4-(dimethylamino)benzoate.

[0016] Furthermore, the photoinitiator includes one or more of 1-hydroxycyclohexyl phenyl ketone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide and phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide.

[0017] Furthermore, the auxiliary agents include: a co-initiator, a thixotropic agent, a functional filler and a coupling agent.

[0018] Furthermore, the co-initiator includes aniline compounds.

[0019] Furthermore, the thixotropic agent includes hydrophobically modified silica.

[0020] Furthermore, the functional filler includes: one or more of modified silica powder, talcum powder and nano calcium carbonate.

[0021] Furthermore, the coupling agent includes a silane coupling agent.

[0022] Furthermore, the auxiliary agent also includes: a colored filler having a fluorescence detection function or a color display function.

[0023] In addition, the present invention also provides a method for preparing a UV-curable and decomposable composition. The method for preparing the UV-curable and decomposable composition as described above specifically includes the following steps:

[0024] preparing a modified polyurethane resin; and

[0025] The modified polyurethane resin is mixed with acrylic monomer, photoinitiator and auxiliary agent to obtain the composition that can be cured and decomposed by ultraviolet light.

[0026] Furthermore, the preparation of the modified polyurethane resin specifically includes: putting the polyol into a reaction kettle for vacuum dehydration; adding isocyanate and a catalyst after cooling to react; and finally adding hydroxycoumarin to react to a predetermined NCO value.

[0027] Furthermore, the molar ratio of the isocyanate to the polyol is 1.1:1 to 2.1:1.

[0028] Furthermore, the molar ratio of the hydroxycoumarin to the polyol is 0.1:1 to 1.1:1.

[0029] Furthermore, the amount of the catalyst used accounts for 0.01-0.05% of the total mass.

[0030] Through the above technical solution, the present invention has the following beneficial effects:

[0031] By introducing specific structural units into the modified polyurethane resin and selecting suitable acrylic monomers, photoinitiators and other components, the composition has good storage stability and can achieve reversible transformation of curing and decomposition under ultraviolet light of different wavelengths, thereby expanding the application range of the composition.

[0032] In addition, a hydroxycoumarin structure is introduced into the modified polyurethane resin, and it is matched with a specific acrylic monomer, a photoinitiator, etc., so that the composition is cured under ultraviolet light with a wavelength of more than 300nm (for example, preferably 350nm), and decomposed under ultraviolet light with a wavelength of less than 254nm (for example, preferably 254nm), thereby achieving controllable curing and decomposition performance. In addition, by selecting specific types of acrylic monomers and photoinitiators and adopting specific ratios, the composition has good curing speed and decomposition efficiency, and has excellent mechanical properties and weather resistance. The use of auxiliary agents further improves the leveling property, storage stability and performance of the composition. DETAILED DESCRIPTION

[0033] A UV-curable and decomposable composition and preparation method of the present invention will be described in more detail below, wherein preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art can modify the present invention described herein and still achieve the beneficial effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the present invention.

[0034] The embodiment of the present invention provides a composition that can be cured and decomposed by ultraviolet light, including: a modified polyurethane resin, an acrylic monomer, a photoinitiator and an auxiliary agent.

[0035] Specifically, the modified polyurethane resin accounts for 70.0-98.8% of the total mass; the acrylic monomer accounts for 0.1-30.0% of the total mass; the photoinitiator accounts for 0.1-5.0% of the total mass; and the auxiliary agent accounts for 1.0-10.0% of the total mass.

[0036] In one embodiment, the modified polyurethane resin comprises components including polyol, isocyanate, catalyst and hydroxycoumarin.

[0037] In this embodiment, the polyol includes: polyether polyol, polyester polyol, polycarbonate polyol or polybutadiene polyol having a hydroxyl value of 28 to 280 mgKOH / g.

[0038] In this embodiment, the isocyanate includes: toluene diisocyanate (i.e., Toluene Diisocyanate, TDI), isophorone diisocyanate (i.e., Isophorone Diisocyanate, IPDI), diphenylmethane diisocyanate (i.e., Methylene Diphenyl Diisocyanate, MDI), dicyclohexylmethane diisocyanate (i.e., Hydrogenated Methylene Diphenyl Diisocyanate, H12MDI) and 1,6-hexamethylene diisocyanate (i.e., Hexamethylene Diisocyanate, HDI) One or more combinations thereof.

[0039] In this embodiment, the catalyst includes: one or more of an organic tin compound, an organic bismuth compound, an organic bismuth zinc compound and an amine compound.

[0040] In this embodiment, the hydroxycoumarin includes: 4-hydroxycoumarin, 4-methyl-7-hydroxycoumarin, 7-hydroxycoumarin, or a combination of more thereof.

[0041] In one embodiment, the acrylic monomer includes: hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofuran (meth)acrylate, isooctyl acrylate, isodecyl acrylate, alkoxydodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloylmorpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate and polycaprolactone modified acrylate. One or more combinations thereof.

[0042] Preferably, the acrylic monomer can be selected from one or more combinations of the above-mentioned acrylic monomers that do not contain a methyl group. Specifically, the acrylic monomer includes one or more combinations of isooctyl acrylate, isodecyl acrylate, alkoxy dodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloyl morpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate and polycaprolactone modified acrylate.

[0043] In one embodiment, the photoinitiator includes: 2-hydroxy-methylphenylpropane-1-one (for example, the model is 1173), 1-hydroxycyclohexylphenyl ketone (for example, the model is 184), 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone (for example, the model is 907), benzoin dimethyl ether (i.e., Benzil Dimethyl Ketal, BDK, for example, the model is 651), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (i.e., Trimethylbenzoyl-diphenylphosphine oxide oxide, TPO), isopropylthioxanthone (i.e., Isopropylthioxanthone, ITX), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (e.g., model 369), phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (e.g., model 819), benzophenone (i.e., Benzophenone, BP), camphorquinone (i.e., Camphorquinone, CQ) and ethyl 4-(dimethylamino)benzoate (i.e., Ethyl 4-(dimethylamino)benzoate, EDAB) One or more thereof.

[0044] Preferably, the photoinitiator includes: one or more of 1-hydroxycyclohexyl phenyl ketone (for example, using model 184), benzoin dimethyl ether (i.e., Benzil Dimethyl Ketal, BDK, for example, using model 651), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (i.e., Trimethylbenzoyl-diphenylphosphine oxide, TPO) and phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide (for example, using model 819).

[0045] The above products with specific models are all from BASF of Germany. A series of photoinitiator products.

[0046] In one embodiment, the auxiliary agent includes: a co-initiator, a thixotropic agent, a functional filler and a coupling agent.

[0047] In this embodiment, the co-initiator includes aniline compounds.

[0048] In this embodiment, the thixotropic agent includes hydrophobically modified silica.

[0049] In this embodiment, the functional filler includes: one or more of modified silica powder, talcum powder and nano calcium carbonate. Those skilled in the art will appreciate that, while achieving the same effect, the functional filler may also include other fillers that can impart functionality to the adhesive.

[0050] In this embodiment, the coupling agent includes a silane coupling agent.

[0051] In one embodiment, the auxiliary agent further includes: a colored filler having a fluorescence detection function or a color display function.

[0052] In addition, this embodiment also provides a method for preparing a UV-curable and decomposable composition. The method for preparing the UV-curable and decomposable composition as described above specifically includes the following steps:

[0053] S1, preparing modified polyurethane resin; and

[0054] S2, mixing the modified polyurethane resin with acrylic monomer, photoinitiator and auxiliary agent to obtain the UV-curable and decomposable composition.

[0055] In step S1, the preparation of the modified polyurethane resin specifically includes: putting polyol into a reaction kettle for vacuum dehydration; adding isocyanate and a catalyst after cooling to react; and finally adding hydroxycoumarin to react to a predetermined NCO value.

[0056] Preferably, the molar ratio of isocyanate to polyol is 1.1:1 to 2.1:1.

[0057] Preferably, the molar ratio of the hydroxycoumarin to the polyol is 0.1:1 to 1.1:1.

[0058] Preferably, the amount of the catalyst used accounts for 0.01-0.05% of the total mass.

[0059] In a specific example, the modified polyurethane resin is prepared and synthesized according to the following process: n mol polyol is put into a spherical reactor, the temperature is raised to 105°C, and vacuum dehydration is performed for 2 hours. The temperature is lowered to 85°C, and (1.1-2.1) nmol isocyanate and catalyst are added while stirring, and the reaction is maintained at a constant temperature for 2 hours. Slowly add (0.1-1.1) nmol hydroxycoumarin to the reactor, and continue to stir at a constant temperature until the NCO value drops to 0.05%. Among them, the amount of catalyst used is 0.01-0.05% of the total mass of the material. It can be known to those skilled in the art that the above specific values ​​can be set according to actual needs.

[0060] In this embodiment, four kinds of modified polyurethane resins are prepared according to the material ratios in Table 1 below. The preparation method is as follows: weigh 50g of polyol in a round-bottom flask and dehydrate and dry at 105°C for 2 hours. After cooling to 85°C, add isocyanate and catalyst respectively according to the ratio in Table 1, and react at a constant temperature for 2 hours. Slowly add hydroxycoumarin and react at a constant temperature until the NCO value is less than 0.05%. In the table, PPG-1000 and PTMG-2000 are polyether polyols purchased from Mitsubishi Chemical (i.e. Mitsubishi Chemical Corporation); PCDX-208 is a polycarbonate polyol purchased from Asahi Kasei (i.e. Asahi Kasei Corporation); LBH-2000 is a polybutadiene polyol purchased from Cray Valley (i.e. Cray Valley Company).

[0061] Table 1

[0062]

[0063]

[0064] Example 1

[0065] According to the following ratio, a UV-curable and decomposable composition was prepared.

[0066] The modified polyurethane resin A accounts for 98.8% of the total mass; the acrylic monomer accounts for 0.1% of the total mass; the photoinitiator accounts for 0.1% of the total mass; and the fumed silica TS720 accounts for 1.0% of the total mass.

[0067] Specifically, take 6-8 mg of glue between two glass substrates, control the thickness of the glue layer to 0.1 mm, and cross-lap the two test pieces. Irradiate the glue with a 350nm ultraviolet lamp to prepare 10 groups of test pieces. Irradiate the 10 groups of test pieces with a 350nm ultraviolet lamp for 8 minutes. Take 5 groups of test pieces and test the flat tensile strength according to standard GB / T 7124 to be 0.37Mpa. Take another 5 groups of test pieces and irradiate them with a 254nm ultraviolet lamp for 8 minutes. Test the flat tensile strength according to standard GB / T 7124 to be 0.03Mpa.

[0068] Example 2

[0069] According to the following ratio, a UV-curable and decomposable composition was prepared.

[0070] The modified polyurethane resin B accounts for 80.0% of the total mass; the isobornyl acrylate accounts for 18.5% of the total mass; the photoinitiator TPO accounts for 0.5% of the total mass; and the fumed silica TS720 accounts for 1.0% of the total mass.

[0071] Specifically, take 6-8 mg of glue between two glass substrates, control the thickness of the glue layer to 0.1 mm, and cross-lap the two test pieces. Irradiate the glue with a 350nm ultraviolet lamp to prepare 10 groups of test pieces. Irradiate the 10 groups of test pieces with a 350nm ultraviolet lamp for 8 minutes. Take 5 groups of test pieces and test the flat tensile strength according to the standard GB / T 7124 to be 0.53Mpa. Take another 5 groups of test pieces and irradiate them with a 254nm ultraviolet lamp for 8 minutes. Test the flat tensile strength according to the standard GB / T 7124 to be 0.10Mpa.

[0072] Example 3

[0073] According to the following ratio, a UV-curable and decomposable composition was prepared.

[0074] The modified polyurethane resin C accounts for 70.0% of the total mass; the N,N-dimethylacrylamide accounts for 25.5% of the total mass; the photoinitiator TPO accounts for 2.5% of the total mass; and the fumed silica TS720 accounts for 2.0% of the total mass.

[0075] Specifically, take 6-8 mg of glue between two glass substrates, control the thickness of the glue layer to 0.1 mm, and cross-lap the two test pieces. Irradiate the glue with a 350nm ultraviolet lamp to prepare 10 groups of test pieces. Irradiate the 10 groups of test pieces with a 350nm ultraviolet lamp for 8 minutes. Take 5 groups of test pieces and test the flat tensile strength according to the standard GB / T 7124 to be 1.48Mpa. Take another 5 groups of test pieces and irradiate them with a 254nm ultraviolet lamp for 8 minutes. Test the flat tensile strength according to the standard GB / T 7124 to be 0.98Mpa.

[0076] Example 4

[0077] According to the following ratio, a UV-curable and decomposable composition was prepared.

[0078] The modified polyurethane resin D accounts for 90.0% of the total mass; the isodecyl acrylate accounts for 7.5% of the total mass; the photoinitiator TPO accounts for 1.5% of the total mass; and the fumed silica TS720 accounts for 1.0% of the total mass.

[0079] Specifically, take 6-8 mg of glue between two glass substrates, control the thickness of the glue layer to 0.1 mm, and cross-lap the two test pieces. Irradiate the glue with a 350nm ultraviolet lamp to prepare 10 groups of test pieces. Irradiate the 10 groups of test pieces with a 350nm ultraviolet lamp for 8 minutes. Take 5 groups of test pieces and test the flat tensile strength according to standard GB / T 7124 to be 0.77Mpa. Take another 5 groups of test pieces and irradiate them with a 254nm ultraviolet lamp for 8 minutes. Test the flat tensile strength according to standard GB / T 7124 to be 0.23Mpa.

[0080] Comparative Example

[0081] A UV-curable temporary protective adhesive was prepared according to the following ratio.

[0082] Resin DR-U317, purchased from Changxing Materials Industry Co., Ltd., accounts for 50% of the total mass; acrylic monomer N,N-dimethylacrylamide accounts for 30% of the total mass; acrylic monomer hydroxyethyl acrylate accounts for 16% of the total mass; photoinitiator accounts for 3% of the total mass; fumed silica TS720 accounts for 1.0% of the total mass.

[0083] Specifically, take 6-8 mg of glue between two glass substrates, control the thickness of the glue layer to 0.1 mm, and cross-lap the two test pieces. Irradiate the glue with a 350nm ultraviolet lamp to prepare 10 groups of test pieces. Irradiate the 10 groups of test pieces with a 350nm ultraviolet lamp for 8 minutes. Take 5 groups of test pieces and test the flat tensile strength according to the standard GB / T 7124 to be 1.51Mpa. Take another 5 groups of test pieces and irradiate them with a 254nm ultraviolet lamp for 8 minutes. Test the flat tensile strength according to the standard GB / T 7124 to be 1.46Mpa.

[0084] By contrast, it can be seen that the intensity of the traditional UV-cured temporary protective glue is only slightly reduced from 1.51MPa to 1.46MPa after 254nm ultraviolet light irradiation, which remains basically unchanged. However, the composition of the present embodiment is significantly reduced in intensity after 254nm ultraviolet light irradiation, which embodies good controllable decomposition performance. Therefore, the present embodiment is irradiated under a light source with a wavelength of more than 300nm, and can be cured to produce bonding force to various substrates. Wherein, the present embodiment is a preferred embodiment with a wavelength of 350nm, which can improve the curing effect. Under the irradiation of a light source less than or equal to 254nm, decomposition can occur, and the cured composition becomes a flowing or viscous liquid again. The present embodiment can be cured and decomposed by ultraviolet light, which can be applied to the temporary protection process of electronic products, and the glue removal conditions are safe and pollution-free, and will not cause damage to the workpiece.

[0085] In summary, the UV-curable and decomposable composition and preparation method proposed in the present invention have the following advantages:

[0086] By introducing specific structural units into the modified polyurethane resin and selecting suitable acrylic monomers, photoinitiators and other components, the composition has good storage stability and can achieve reversible transformation of curing and decomposition under ultraviolet light of different wavelengths, thereby expanding the application range of the composition.

[0087] In addition, a hydroxycoumarin structure is introduced into the modified polyurethane resin, and it is matched with a specific acrylic monomer, a photoinitiator, etc., so that the composition is cured under ultraviolet light with a wavelength of more than 300nm (for example, preferably 350nm), and decomposed under ultraviolet light with a wavelength of less than 254nm (for example, preferably 254nm), thereby achieving controllable curing and decomposition performance. In addition, by selecting specific types of acrylic monomers and photoinitiators and adopting specific ratios, the composition has good curing speed and decomposition efficiency, and has excellent mechanical properties and weather resistance. The use of auxiliary agents further improves the leveling property, storage stability and performance of the composition.

[0088] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A UV-curable and decomposable composition, characterized in that: include: Modified polyurethane resin, acrylic monomer, photoinitiator and additives; The modified polyurethane resin accounts for 70.0-98.8% of the total mass; the acrylic monomer accounts for 0.1-30.0% of the total mass; the photoinitiator accounts for 0.1-5.0% of the total mass; and the auxiliary agent accounts for 1.0-10.0% of the total mass.

2. The UV-curable and decomposable composition according to claim 1, characterized in that The modified polyurethane resin comprises components of polyol, isocyanate, catalyst and hydroxycoumarin.

3. The UV-curable and decomposable composition according to claim 2, characterized in that The polyol includes: polyether polyol, polyester polyol, polycarbonate polyol or polybutadiene polyol with a hydroxyl value of 28 to 280 mgKOH / g.

4. The UV-curable and decomposable composition according to claim 2, characterized in that The isocyanate includes: toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and 1,6-hexamethylene diisocyanate, or a combination of more than one thereof.

5. The UV-curable and decomposable composition according to claim 2, characterized in that: The catalyst comprises: one or a combination of organic tin compounds, organic bismuth compounds, organic bismuth zinc compounds and amine compounds.

6. The UV-curable and decomposable composition according to claim 2, characterized in that The hydroxycoumarin includes: 4-hydroxycoumarin, 4-methyl-7-hydroxycoumarin, 7-hydroxycoumarin, or a combination of more than one thereof.

7. The UV-curable and decomposable composition according to claim 2, characterized in that: The acrylic monomers include: hydroxyethyl (meth)acrylate, hydroxybutyl (meth)acrylate, isobornyl (meth)acrylate, tetrahydrofuran (meth)acrylate, isooctyl acrylate, isodecyl acrylate, alkoxydodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloylmorpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate and polycaprolactone modified acrylate. One or more combinations thereof.

8. The UV-curable and decomposable composition according to claim 7, characterized in that The acrylic monomer includes: one or more combinations of isooctyl acrylate, isodecyl acrylate, alkoxydodecyl acrylate, vinyl neodecanoate, N,N-dimethylacrylamide, N,N-diethylacrylamide, acryloylmorpholine, 3,3,5-trimethylcyclohexyl acrylate, 2-phenoxyethyl acrylate, trimethylolpropane formal acrylate and polycaprolactone modified acrylate.

9. The UV-curable and decomposable composition according to claim 1, characterized in that The photoinitiator includes: one or more of 2-hydroxy-methylphenylpropane-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinyl-1-propanone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, isopropylthioxanthone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzophenone, camphorquinone and ethyl 4-(dimethylamino)benzoate.

10. The UV-curable and decomposable composition according to claim 9, characterized in that The photoinitiator includes one or more of 1-hydroxycyclohexyl phenyl ketone, benzoin dimethyl ether, 2,4,6-trimethylbenzoyl diphenyl phosphine oxide and phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide.

11. The UV-curable and decomposable composition according to claim 1, characterized in that The auxiliary agents include: auxiliary initiator, thixotropic agent, functional filler and coupling agent.

12. The UV-curable and decomposable composition according to claim 11, characterized in that The auxiliary initiator includes aniline compounds.

13. The UV-curable and decomposable composition according to claim 11, characterized in that The thixotropic agent includes hydrophobically modified silica.

14. The UV-curable and decomposable composition according to claim 11, characterized in that The functional filler includes: one or more of modified silica powder, talcum powder and nano calcium carbonate.

15. The UV-curable and decomposable composition according to claim 11, characterized in that The coupling agent includes a silane coupling agent.

16. The UV-curable and decomposable composition according to claim 11, characterized in that The auxiliary agent also includes: a colored filler having a fluorescence detection function or a color display function.

17. A method for preparing a UV-curable and decomposable composition, comprising preparing the UV-curable and decomposable composition according to any one of claims 1 to 16, characterized in that: The details include: preparing a modified polyurethane resin; and The modified polyurethane resin is mixed with acrylic monomer, photoinitiator and auxiliary agent to obtain the composition that can be cured and decomposed by ultraviolet light.

18. The method for preparing a UV-curable and decomposable composition according to claim 17, characterized in that: The preparation of the modified polyurethane resin specifically comprises: putting polyol into a reaction kettle for vacuum dehydration; adding isocyanate and a catalyst after cooling to react; and finally adding hydroxycoumarin to react to a predetermined NCO value.

19. The method for preparing a UV-curable and decomposable composition according to claim 18, characterized in that: The molar ratio of the isocyanate to the polyol is 1.1:1 to 2.1:

1.

20. The method for preparing a UV-curable and decomposable composition according to claim 18, characterized in that: The molar ratio of the hydroxycoumarin to the polyol is 0.1:1 to 1.1:

1.

21. The method for preparing a UV-curable and decomposable composition according to claim 18, wherein: The amount of the catalyst used accounts for 0.01-0.05% of the total mass.

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