Low-surface-energy macromolecular photoinitiator, UV (ultraviolet) LED (light-emitting diode) photocureable coating and photocureable skin-touch coating

Abstract

The invention provides a low-surface-energy macromolecular photoinitiator, a UV (ultraviolet) LED (light-emitting diode) photocureable coating and a photocureable skin-touch coating. The low-surface-energy macromolecular photoinitiator comprises an ultraviolet light initiator chain segment, a coinitiator amine molecular chain segment, a low-surface-energy chain segment and a functional end group which are arranged repeatedly, and the ultraviolet light initiator chain segment, the coinitiator amine molecular chain segment, the low-surface-energy chain segment and the functional end group are randomly connected through single bonds. The low surface energy chain segment comprises one or more of C1-C30 divalent alkyl and divalent siloxy which are partially substituted or completely substituted by fluorine atoms; the amine molecular chain segment of the co-initiator can be used as a hydrogen donor of an ultraviolet light initiator chain segment, so that the photo-initiation efficiency can be improved; due to the introduction of the low-surface-energy chain segment, the low-surface-energy macromolecular photoinitiator has a certain migration ability, self-assembly can occur on the surface of a coating after film coating, the oxygen isolation ability is improved, and a skin feeling layer is formed through illumination; the functional end group participates in thermocuring, so that the mechanical property of the coating is improved.

Description

Technical Field

[0001] The present application relates to the technical field of photocurable coatings, and in particular to low surface energy macromolecular photoinitiators, UV LED photocurable coatings, and photocurable skin-feel coatings. Background Art

[0002] UV curing technology is an environmentally friendly, energy-saving, efficient, adaptable, practical and economical material surface treatment technology. For UV-curing coatings, especially free radical polymerization photocuring coatings, there are usually two problems on the product side: one is that the free radicals in the free radical polymerization process are easily quenched by oxygen, which makes the surface of the coating incompletely cured or unable to cure, which in turn leads to the problem of stickiness of the coating; the other is the wrinkling problem on the coating surface caused by the change in the connection mode between molecules before and after curing and the change in the free volume in the system. In recent years, researchers have found that the wrinkled pattern on the surface of UV-cured coatings can effectively improve the feel of the coating, that is, skin-feel coatings.

[0003] At present, skin-feel coatings are prepared by UV curing process, and the photoinitiators in the photocuring system are mostly small molecule photoinitiators. During the use of the products, problems such as migration of initiators, strong odor of cured products, and surface stickiness of products caused by surface oxygen inhibition are prone to occur. In addition, the photocuring process mainly relies on 172nm ultraviolet excimer curing, electron beam curing equipment or UV LED curing devices. At present, multi-step curing processes such as the combination of excimer lamps and mercury lamps, or layered curing processes are mainly used. It is rare to rely on a single curing device or process to achieve coating curing. This leads to the need for the compounding of multiple photoinitiators on the one hand, which puts higher requirements on the system formula design and preparation; on the other hand, due to the oxygen inhibition effect of oxygen in the air on the photo-initiated polymerization reaction, it is usually necessary to isolate oxygen, which undoubtedly increases the complexity of the process. Summary of the invention

[0004] In view of the above problems, the embodiments of the present application provide a low surface energy macromolecular photoinitiator, a UV LED photocuring coating and a photocuring skin-feel coating, which can effectively block the diffusion of oxygen into the curing system, solve the problem of oxygen inhibition in the curing process, and simplify the curing process.

[0005] In a first aspect, an embodiment of the present application provides a low surface energy macromolecular photoinitiator, the low surface energy macromolecular photoinitiator comprising a repeatedly arranged ultraviolet light initiator segment (PI), a co-initiator amine molecular segment (Co), a low surface energy segment (P), a first functional end group (E1) and a second functional end group (E2), the ultraviolet light initiator segment, the co-initiator amine molecular segment, the low surface energy segment, the first functional end group (E1) and the second functional end group (E2) are randomly connected by a single bond; the low surface energy macromolecular photoinitiator has a structure shown in Formula I:

[0006]

[0007] The low surface energy segment includes one or more of a C1-C30 divalent alkyl group or a divalent siloxy group partially or completely substituted with fluorine atoms;

[0008] The first terminal group and the second terminal group are independently selected from one of an amino group, an epoxy group, and a hydroxyl group.

[0009] According to an embodiment of the first aspect of the present application, the ultraviolet photoinitiator segment is formed by a small molecule ultraviolet photoinitiator.

[0010] According to the implementation of the first aspect of the present application, the coinitiator amine molecular segment is formed by a diamine molecule.

[0011] According to an embodiment of the first aspect of the present application, the divalent siloxy group is formed by a polydimethylsiloxane including a capping group, and the capping group includes at least one of a hydroxyl group, an epoxy group, and an amino group.

[0012] According to an embodiment of the first aspect of the present application, the C1-C30 divalent alkyl carbon fluoro chain segment partially or completely substituted with fluorine atoms is formed by perfluoropolyether diol.

[0013] According to the implementation of the first aspect of the present application, the small molecule ultraviolet photoinitiator includes one or more of benzophenone photoinitiators, thioxanthone photoinitiators, and coumarin.

[0014] According to the implementation of the first aspect of the present application, the ultraviolet initiator segment includes at least one of the structures shown in Formula 1:

[0015]

[0016] Among them, # indicates the connection point.

[0017] According to the implementation of the first aspect of the present application, the coinitiator amine molecular segment includes at least one of the structures shown in Formula 2:

[0018]

[0019] Among them, # indicates the connection point;

[0020] R 1 One selected from a C1-C12 divalent alkyl group, a C1-C12 divalent alkenyl group, and a C1-C12 divalent alkoxy group;

[0021] R 2 An alkyl group selected from C1-C3; R 2 One selected from a C1-C12 divalent alkyl group, a C1-C12 divalent alkenyl group, and a C1-C12 divalent alkoxy group.

[0022] In a second aspect, the present application provides a method for preparing a low surface energy macromolecular photoinitiator, comprising the following steps:

[0023] A small molecule ultraviolet light initiator is reacted with a diamine molecule in a first solvent, and an intermediate is obtained by filtering and drying;

[0024] The intermediate is reacted with polydimethylsiloxane having a blocking group in a second solvent, and the low surface energy macromolecular photoinitiator is obtained by filtering and drying, wherein the blocking group includes at least one of a hydroxyl group, an epoxy group, and an amino group;

[0025] Alternatively, the intermediate is reacted with perfluoropolyether diol in a second solvent, and the low surface energy macromolecular photoinitiator is obtained by filtering and drying.

[0026] In a third aspect, an embodiment of the present application provides a UV LED light-curing coating, comprising the low surface energy macromolecular photoinitiator in the embodiment of the first aspect of the present application.

[0027] According to the implementation of the third aspect of the present application, the UV LED light-curing coating includes: 10-40wt% acrylate monomer content; 20-60wt% UV curing resin content; 5-30wt% crosslinking agent content; and 1.0-10.0wt% low surface energy macromolecular photoinitiator content.

[0028] According to an embodiment of the third aspect of the present application, the UV curable resin is selected from one or a combination of polyester polyurethane acrylate, polyether polyurethane acrylate, polyester acrylate and polyether acrylate.

[0029] According to an embodiment of the third aspect of the present application, the cross-linking agent is selected from one or a combination of trifunctional acrylate, tetrafunctional acrylate, pentafunctional acrylate and hexafunctional acrylate.

[0030] In a third aspect, an embodiment of the present application provides a photocurable skin-feel coating, and the photocurable skin-feel coating is obtained by ultraviolet light curing of the UV LED photocurable coating in the embodiment of the second aspect of the present application.

[0031] Compared with the prior art, this application has at least the following beneficial effects:

[0032] The present application connects a small molecule UV photoinitiator segment with a co-initiator amine molecular segment and a connecting low surface energy segment. On the one hand, the segment length of the small molecule UV photoinitiator segment is increased, and the migration performance of the small molecule UV photoinitiator is improved. On the other hand, the co-initiator amine molecular segment can be used as a hydrogen donor for the UV photoinitiator segment, which helps to improve the photoinitiation efficiency. The introduction of the low surface energy segment enables the low surface energy macromolecular photoinitiator to have a certain migration ability. After coating, it will self-assemble on the coating surface to form a gradient distribution of concentration in the system, which can then induce gradient polymerization. The low surface energy macromolecular photoinitiator that migrates to the surface can form an oxygen barrier layer, which has a certain anti-oxygen inhibition effect. It can not only effectively block the diffusion of oxygen into the curing system, but also solve the problem of oxygen inhibition during the curing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying creative work.

[0034] Figure 1 The surface morphology of the skin-feel coating prepared in Example 1;

[0035] Figure 2 is the water contact angle of the skin-feel coating surface prepared in Example 1;

[0036] Figure 3 The surface morphology of the skin-feel coating prepared in Example 2;

[0037] Figure 4 is the water contact angle of the skin-feel coating surface prepared in Example 2;

[0038] Figure 5 The surface morphology of the skin-feel coating prepared in Example 3;

[0039] Figure 6 is the water contact angle of the skin-feel coating surface prepared in Example 3. DETAILED DESCRIPTION

[0040] In order to make the application purpose, technical solution and beneficial technical effect of the present application clearer, the present application is further described in detail in conjunction with the embodiments below. It should be understood that the embodiments described in this specification are only for explaining the present application, not for limiting the present application.

[0041] For simplicity, this application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0042] In this specification, the substituent of compound is disclosed with combination range.It is clearly expected that this description includes each individual sub-combination of the member of these groups and scope.For example, it is clearly expected that the term "C12-C18 aromatic amine group" discloses the aromatic amine group of C12, C13, C14, C15, C16, C17, C18, C12-C18, C12-C17, C12-C16, C12-C15, C12-C14, C12-C13, C12-C17, C13-C16, C13-C15, C13-C14, C14-C18, C14-C17, C14-C16, C14-C15, C15-C18, C15-C17, C15-C16, C16-C18 and C16-C17 individually.

[0043] In the description of the present application, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number, and the “multiple” in “one or more” means two or more than two.

[0044] The above application content of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided by a series of examples, which can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0045] At present, in the preparation process of UV-curable skin-feel coatings, small molecule photoinitiators have the problems of easy migration, strong odor of cured products, easy inhibition by oxygen, and complex curing equipment and process requirements.

[0046] Based on this, the inventors of this application have provided a low surface energy macromolecular photoinitiator, UV LED photocuring coating and photocuring skin-feel coating through research, which can effectively block the diffusion of oxygen into the curing system, solve the problem of oxygen inhibition in the curing process, and simplify the curing process.

[0047] In the first aspect, the embodiment of the present application provides a low surface energy macromolecular photoinitiator, which includes a plurality of UV initiator segments (PI) arranged repeatedly and alternately, a plurality of coinitiator amine molecular segments (Co) and a plurality of low surface energy segments (P) and a first functional end group (E1) and a second functional end group (E2), and the UV initiator segments, the coinitiator amine molecular segments, the low surface energy segments, the first functional end group and the second functional end group are randomly connected by single bonds; the low surface energy segments include one or more of C1-C30 divalent alkyl and divalent siloxy groups partially or completely substituted by fluorine atoms. The first functional end group and the second functional end group are independently selected from one of amino, epoxy and hydroxyl groups. The low surface energy macromolecular photoinitiator has a structure shown in Formula I:

[0048]

[0049] The molecular skeleton of the low surface energy macromolecular photoinitiator contains an ultraviolet photoinitiator chain segment, and the ultraviolet photoinitiator chain segment can generate free radicals under the irradiation of ultraviolet light to initiate a free radical polymerization reaction.

[0050] The random connection between the UV photoinitiator segment, the co-initiator amine molecular segment, the low surface energy segment, the first functional end group and the second functional end group through single bonds means that: on the one hand, the above segments are connected to each other through single bonds, and the above segments and the functional end groups are connected through single bonds; on the other hand, the positions of the UV photoinitiator segment (PI), the co-initiator amine molecular segment (Co), and the low surface energy segment (P) are not fixed when they are repeatedly arranged, and the order is adjustable, for example, it can be a -PI-Co-P-Co-PI- arrangement or a -PI-Co-PI-Co-P- arrangement.

[0051] By adjusting the ratio of each segment, the first functional end group can be connected to any one of the PI, Co, and P segments; or the second functional end group can be connected to any one of the PI, Co, and P segments. Preferably, the first functional end group and the second functional end group are connected to the P segment, which can reduce the difficulty of synthesis.

[0052] The molecular skeleton of the low-surface-energy macromolecular photoinitiator contains a co-initiator amine molecular segment, which is randomly connected to the ultraviolet light initiator segment by a single bond through a nitrogen atom, and the carbon atom adjacent to the nitrogen atom in the co-initiator amine molecular segment is connected with hydrogen, so the co-initiator amine molecular segment can supply hydrogen to the ultraviolet light initiator segment, which helps to improve the photoinitiation efficiency. The molecular skeleton of the low-surface-energy macromolecular photoinitiator contains a low-surface-energy segment, which includes one or more of a C1-C30 divalent alkyl group and a divalent siloxy group partially or completely substituted with a fluorine atom, and the low-surface-energy segment is connected to the nitrogen atom in the co-initiator amine molecular segment by a single bond. The low surface tension and low surface energy of fluorine atoms and siloxanes endow low-surface-energy macromolecular photoinitiators with a certain migration ability, which enables them to spontaneously migrate to the outer surface of the system in the photocuring coating system, and eventually form a concentration gradient distribution in the system, which can then initiate gradient polymerization; the fluorine-containing low-surface-energy macromolecular photoinitiators that partially migrate to the surface can form an oxygen-isolating layer, which has a certain anti-oxidation and anti-polymerization effect.

[0053] When the photocurable coating containing the low surface energy macromolecular photoinitiator of the embodiment of the present application is applied on different substrate materials by scraping, spraying or spin coating, a coating to be cured of a certain thickness is formed. The coating is irradiated with ultraviolet light using an LED light source. During the illumination, the surface layer is first cured, and the volume shrinks to form a surface wrinkle pattern. As the photocuring process proceeds, the bottom layer is cured and the surface wrinkle morphology is fixed to form a skin-feel coating. During the illumination process, the distance between the light source and the coating, the illumination intensity, and the illumination time can be adjusted according to the thickness of the coating. For example, the wavelength of the LED light source is 365nm, the light source power is 100-700mJ / cm2, and the illumination time is 10s-30min. The divalent has two free radicals, the divalent alkyl refers to an alkyl with two free radicals, and the divalent siloxy refers to a siloxy with two free radicals.

[0054] The first functional end group E1 is selected from one of amino, epoxy, and hydroxyl groups; the second functional end group E2 is selected from one of amino, epoxy, and hydroxyl groups. The first functional end group E1 and the second functional end group E2 may be the same or different. In the embodiment of the present application, by setting the first functional end group E1 and the second functional end group E2, after the low surface energy macromolecular photoinitiator completes photocuring to form a skin-feel coating, thermal curing is continued to improve the thermal stability and mechanical stability of the skin-feel coating. Exemplarily, E1 and E2 are both amino groups, and an epoxy-terminated reagent can be added to complete the thermal curing process. Or E1 and E2 are both hydroxyl groups, and an isocyanate-terminated reagent can be added to complete the thermal curing process. This application connects the small molecule ultraviolet light initiator chain segment with the co-initiator amine molecule chain segment and the connecting low surface energy chain segment. On the one hand, the chain segment length of the small molecule ultraviolet light initiator chain segment is increased, and the migration performance of the small molecule ultraviolet light initiator is improved. On the other hand, the co-initiator amine molecule chain segment can be used as a hydrogen donor for the ultraviolet light initiator chain segment, which helps to improve the light initiation efficiency; the introduction of the low surface energy chain segment enables the low surface energy macromolecule photoinitiator to have a certain migration ability, and self-assembly will occur on the coating surface after coating, forming a gradient distribution of concentration in the system, which can then induce gradient polymerization, and the low surface energy macromolecule photoinitiator that migrates to the surface can form an oxygen barrier layer, which has a certain anti-oxygen inhibition effect, and can not only effectively block the diffusion of oxygen into the curing system, but also solve the problem of oxygen inhibition in the curing process. In addition, the ultraviolet light initiator chain segment is connected to the co-initiator amine molecule chain segment and the connecting low surface energy chain segment through a single bond connection, which reduces the steric hindrance between the groups and is conducive to improving the light initiation efficiency.

[0055] In some embodiments, the UV-initiator segment is formed by a small molecule UV-initiator. In some embodiments, the small molecule UV-initiator includes one or more of a benzophenone photoinitiator, a thioxanthone photoinitiator, and a coumarin.

[0056] In some embodiments, the coinitiator amine molecular segments are formed from diamine molecules.

[0057] Exemplarily, the benzophenone-based photoinitiator includes one or more of difluorobenzophenone and dichlorobenzophenone, and the difluorobenzophenone undergoes a substitution reaction, in which the fluorine atoms in the difluorobenzophenone undergo a substitution reaction with the diamine, and the fluorine atoms are replaced by the co-initiator amine molecular chain segments to form benzophenone segments.

[0058] In some embodiments, the divalent siloxy group is formed from a polydimethylsiloxane including a capping group, and the capping group includes at least one of a hydroxyl group, an epoxy group, and an amino group.

[0059] For example, the polydimethylsiloxane with end groups can be diepoxy polydimethylsiloxane, dihydroxy end-capped polydimethylsiloxane, or diamino end-capped polydimethylsiloxane. Hydroxyl, epoxy, and amino groups are easy to react with amino groups for grafting.

[0060] In some embodiments, the divalent alkyl fluorocarbon chain segment having 1 to 30 carbon atoms partially or completely substituted with fluorine atoms is formed by perfluoropolyether diol.

[0061] The formation price of perfluoropolyether diol is relatively low, which is beneficial to reducing costs.

[0062] According to the implementation of the first aspect of the present application, the ultraviolet initiator segment includes at least one of the structures shown in Formula 1:

[0063]

[0064] Among them, # indicates the connection point.

[0065] According to the implementation of the first aspect of the present application, the coinitiator amine molecular segment includes at least one of the structures shown in Formula 2:

[0066]

[0067] Among them, # indicates the connection point;

[0068] R 1 One selected from a C1-C12 divalent alkyl group, a C1-C12 divalent alkenyl group, and a C1-C12 divalent alkoxy group;

[0069] R 2 An alkyl group selected from C1-C3; R 2 One selected from a C1-C12 divalent alkyl group, a C1-C12 divalent alkenyl group, and a C1-C12 divalent alkoxy group.

[0070] In a second aspect, the present application provides a method for preparing a low surface energy macromolecular photoinitiator, comprising the following steps:

[0071] A small molecule ultraviolet light initiator is reacted with a diamine molecule in a first solvent, and an intermediate is obtained by filtering and drying;

[0072] The intermediate is reacted with polydimethylsiloxane having a blocking group in a second solvent, and the low surface energy macromolecular photoinitiator is obtained by filtering and drying, wherein the blocking group includes at least one of a hydroxyl group, an epoxy group, and an amino group;

[0073] Alternatively, the intermediate is reacted with perfluoropolyether diol in a second solvent, and the low surface energy macromolecular photoinitiator is obtained by filtering and drying.

[0074] In some embodiments, the step of reacting the small molecule ultraviolet initiator with the diamine molecule in the first solvent is performed in an inert gas atmosphere, such as nitrogen. Exemplarily, the reaction temperature is 150° C. and the reaction time is 48 hours.

[0075] The first solvent includes one of dimethyl sulfoxide and water.

[0076] In some embodiments, the intermediate is reacted with the end-capping polydimethylsiloxane in a second solvent in an inert gas atmosphere, such as nitrogen. Exemplarily, the reaction temperature is 50° C. and the reaction time is 12 h.

[0077] The first solvent includes one of chloroform, carbon tetrachloride and the like.

[0078] In a third aspect, an embodiment of the present application provides a UV LED light-curing coating, comprising the low surface energy macromolecular photoinitiator in the embodiment of the first aspect of the present application.

[0079] The UV LED light-curing coating in the embodiment of the present application includes the low surface energy macromolecular photoinitiator in the embodiment of the present application. After the UV LED light-curing coating is coated, the low surface energy macromolecular photoinitiator will self-assemble on the surface of the coating, which can not only effectively block the diffusion of oxygen into the curing system and solve the problem of oxygen inhibition in the curing process; but also can avoid the problem of easy migration of small molecule photoinitiators during the later use of the product, and at the same time give the coating better fingerprint resistance; the surface self-assembly of the low surface energy macromolecular photoinitiator can form an initiator distribution gradient in the depth direction of the curing system. In the subsequent light curing process, the surface layer first solidifies and shrinks to produce wrinkles, and the bottom layer gradually solidifies to fix the wrinkle morphology of the surface layer, that is, to form a skin-feel coating. The above-mentioned curing process only needs to use an ultraviolet LED lamp with a wavelength of 365nm for curing, and no oxygen isolation treatment is required, which can greatly simplify the process flow. After completing the light curing to form a skin-feel coating, thermal curing can be continued to improve the thermal stability and mechanical stability of the skin-feel coating.

[0080] The coating can be applied by blade coating, spray coating or spin coating.

[0081] In some embodiments, the UV LED light-curable coating comprises: 10-40 wt % of acrylate monomer; 20-60 wt % of UV curable resin; 5-30 wt % of cross-linking agent; and 1.0-10.0 wt % of low surface energy macromolecular photoinitiator.

[0082] UV LED light-curing coatings have simple composition and preparation process, and do not require complicated dispersion procedures such as the use of dispersers and subsequent defoaming processes. They are also widely applicable and can be used on a variety of substrates, such as glass, paper, metal, plastic, ceramics, etc. The remaining components in the formula have all been commercially produced.

[0083] In some embodiments, the UV curable resin is selected from one or a combination of polyester polyurethane acrylate, polyether polyurethane acrylate, polyester acrylate and polyether acrylate.

[0084] Exemplarily, the UV curable resin is selected from one or a combination of 8810 polyester polyurethane acrylate, 8805 polyether polyurethane acrylate, 8831 polyester acrylate, and PPGDA polyether acrylate of Jiaxing Sudi Polymer Materials Co., Ltd.

[0085] In some embodiments, the crosslinking agent is selected from one or a combination of trifunctional acrylate, tetrafunctional acrylate, pentafunctional acrylate and hexafunctional acrylate.

[0086] In a third aspect, an embodiment of the present application provides a photocurable skin-feel coating, and the photocurable skin-feel coating is obtained by ultraviolet light curing of the UV LED photocurable coating in the embodiment of the second aspect of the present application.

[0087] Example

[0088] The following examples describe the disclosure of the present application in more detail, and these examples are intended for illustrative purposes only, as it will be apparent to those skilled in the art that various modifications and variations may be made within the scope of the disclosure of the present application. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0089] Embodiment 1:

[0090] (1) Preparation of macromolecular photoinitiators containing low surface energy.

[0091] 1.6g of thiosalicylic acid was slowly added to 15ml of concentrated sulfuric acid at room temperature, and stirred for 5min. Then, 7.0g of p-hydroxyphenol was added under stirring, and stirred for 60min at room temperature, and then the temperature was raised to 80℃ for 2h, and then the temperature was lowered to room temperature overnight. The reaction solution was introduced into 150ml of boiling water and boiled for 10min, filtered, washed with water, and recrystallized from 1,4-dioxane / water (v / v=4 / 1) to obtain a brown-red product. 2.4g of the product, 15ml of epichlorohydrin, 5g of anhydrous potassium carbonate, 20ml of cyclohexanone and 0.5ml of polyethylene glycol were added to a three-necked flask, stirred at 80℃ for 2h, heated to 135℃ for 1h, cooled to room temperature, and the organic layer was poured out. Yellow powder was obtained by rotary evaporation, extraction with chloroform / water, and recrystallization with benzene / ethanol (v / v=1 / 6).

[0092] Dissolve 27 mmol of the yellow powder in 50 ml of dimethyl sulfoxide, add 0.27 mol of piperazine, and react at 150 ° C for 48 hours under nitrogen protection. Cool to room temperature, precipitate the reaction solution in ice water, and filter and dry to obtain a yellow powder. Dissolve 2.0 mmol of the yellow-pink powder and 1.9-2.1 mmol of diepoxy-terminated polydimethylsiloxane P in 20 mL of chloroform, and react at 65 ° C for 12 hours under nitrogen protection. Cool to room temperature, precipitate the reaction solution in anhydrous ether, and filter and dry to obtain a macromolecular photoinitiator Photoinitiator 1 with low surface energy, whose structural formula is as follows.

[0093]

[0094] (2) Preparation of photocuring system: 1.5 g of the above-mentioned photoinitiator Photoinitiator 1, 5.0 g of 1,6-hexanediol diacrylate, 8.5 g of 8810 polyester polyurethane acrylate, and 1.5 g of TMPTA were added to a sample bottle, and 4.0 g of amino (meth) acrylate were mixed by stirring to form a light yellow transparent solution.

[0095] (3) Preparation of skin-sensitive photocurable coating. The above photocurable system was scraped onto a glass plate with a thickness of 100 μm and then exposed to 365 nm ultraviolet light (power 200 mJ / cm 2 , lamp sample distance 10cm) for 3min. A skin-feel coating with a wrinkled surface was obtained. Figure 1 The surface water contact angle is as follows: Figure 2 shown.

[0096] (4) Thermal curing improves the mechanical properties of the coating. The above coating is placed on a heater, nitrogen is passed through to deoxygenate for half an hour, and heated to 80°C for 2 hours to obtain a mechanically enhanced skin-feel coating.

[0097] Embodiment 2:

[0098] (1) Preparation of macromolecular photoinitiators containing low surface energy.

[0099] 0.05 mol 4,4'-difluorobenzophenone, 0.2 mol 2-(methylamino)ethanol, and 0.1 mol K2CO3 were dissolved in 100 mL DMSO and reacted at 140°C for 24 h under nitrogen protection. After cooling to room temperature, the reaction solution was precipitated in ice water, filtered and dried to obtain a bright yellow powder solid product; 0.01 mol of the above yellow powder, 0.004 mol polyperfluoroethoxymethoxydifluoroethyl PEG ether, and 0.006 mol hexamethylene diisocyanate were dissolved in 15 mL DMF, reacted at 80°C for 4 h under nitrogen protection, and then 0.005 mol 4-chloro-1-butylamine was added and the reaction continued at 110°C for 4 h. After cooling to room temperature, the reaction solution was precipitated in methanol, filtered and dried to obtain a macromolecular photoinitiator 2 with low surface energy.

[0100] The structure of the macromolecular photoinitiator Photoinitiator2 is shown below:

[0101]

[0102] (2) Preparation of light curing system.

[0103] 0.3 g of the above-mentioned photoinitiator Photoinitiator 2, 5.0 g of acryloylmorpholine, 6.0 g of PPGDA polyether acrylate, 1.0 g of 8831 polyester acrylate, 2.0 g of bisphenol A diglycidyl ether and 1.5 g of GPTA were added into a sample bottle and stirred to form a light yellow transparent solution.

[0104] (3) Preparation of skin-sensitive photocurable coating. The above photocurable system was scraped onto a metal aluminum plate with a thickness of 50 μm and then irradiated with 365 nm ultraviolet light (power 100 mJ / cm 2 , lamp sample distance 10cm) for 2min. A skin-feel coating with a wrinkled surface was obtained. Figure 3 The surface water contact angle is shown in Figure 4 .

[0105] (4) Thermal curing improves the mechanical properties of the coating. The above coating is placed on a heater, nitrogen is passed through to deoxygenate for half an hour, and then heated to 100°C for one hour to obtain a mechanically enhanced skin-feel coating.

[0106] Embodiment 3:

[0107] (1) Preparation of macromolecular photoinitiators containing low surface energy.

[0108] 0.05 mol 4,4'-difluorobenzophenone, 0.15 mol hydroxyethylpiperazine, and 0.1 mol K2CO3 were dissolved in 100 mL DMSO and reacted at 140°C for 24 h under nitrogen protection. After cooling to room temperature, the reaction solution was precipitated in ice water, filtered and dried to obtain a bright yellow powder solid product; 0.01 mol of the above yellow powder, 0.004 mol polyperfluoroethoxymethoxydifluoroethyl PEG ether, and 0.006 mol hexamethylene diisocyanate were dissolved in 15 mL DMF, reacted at 80°C for 2 h under nitrogen protection, and then 0.005 mol 4-chloro-1-butylamine was added and the reaction continued at 110°C for 4 h. After cooling to room temperature, the reaction solution was precipitated in methanol, filtered and dried to obtain a macromolecular photoinitiator 3 with low surface energy.

[0109] The structural formula of the macromolecular photoinitiator Photoinitiator 3 is as follows:

[0110]

[0111] (2) Preparation of light curing system.

[0112] 1.0 g of the above-mentioned photoinitiator Photoinitiator 3, 3.5 g of poly(ethylene glycol) diacrylate, 6.5 g of PPGDA polyether acrylate, 0.5 g of diglycidyl ether and 1.8 g of TMPTA were added into a sample bottle and stirred to form a light yellow transparent solution.

[0113] (3) Preparation of skin-sensitive photocurable coating. The above photocurable system was scraped onto a metal aluminum plate with a thickness of 30 μm and then irradiated with 365 nm ultraviolet light (power 300 mJ / cm 2 , lamp sample distance 10cm) irradiation for 30s. A skin-feel coating with a wrinkled surface was obtained. Figure 5 The surface water contact angle is shown in Figure 6 .

[0114] (4) Thermal curing improves the mechanical properties of the coating. The above coating is placed on a heater, nitrogen is passed through to deoxygenate for half an hour, and then heated to 100°C for one hour to obtain a mechanically enhanced skin-feel coating.

[0115] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A low surface energy macromolecular photoinitiator, characterized in that: The low surface energy macromolecular photoinitiator comprises a repeatedly arranged ultraviolet light initiator segment (PI), a co-initiator amine molecular segment (Co), a low surface energy segment (P), a first functional end group (E1) and a second functional end group (E2), wherein the ultraviolet light initiator segment, the co-initiator amine molecular segment, the low surface energy segment, the first functional end group and the second functional end group are randomly connected by a single bond; the low surface energy macromolecular photoinitiator has a structure shown in Formula I: The low surface energy segment includes one or more of a C1-C30 divalent alkyl group and a divalent siloxy group partially or completely substituted with fluorine atoms; The first functional end group and the second functional end group are independently selected from one of an amino group, an epoxy group, and a hydroxyl group.

2. The low surface energy macromolecular photoinitiator according to claim 1, characterized in that: The ultraviolet photoinitiator chain segment is formed by a small molecule ultraviolet photoinitiator; and / or, The co-initiator amine molecular chain segments are formed by diamine molecules; and / or, The divalent siloxy group is formed by polydimethylsiloxane including a capping group, and the capping group includes at least one of a hydroxyl group, an epoxy group, and an amino group.

3. The low surface energy macromolecular photoinitiator according to claim 1, characterized in that: The small molecule ultraviolet photoinitiator includes one or more of benzophenone photoinitiators, thioxanthone photoinitiators, and coumarin.

4. The low surface energy macromolecular photoinitiator according to any one of claims 1 to 3, characterized in that: The ultraviolet light initiator segment includes at least one of the structures shown in Formula 1: Among them, # indicates the connection point.

5. The low surface energy macromolecular photoinitiator according to any one of claims 1 to 3, characterized in that: The co-initiator amine molecular segment includes at least one of the structures shown in Formula 2: Among them, # indicates the connection point; R 1 One selected from a C1-C12 divalent alkyl group, a C1-C12 divalent alkenyl group, and a C1-C12 divalent alkoxy group; R 2 An alkyl group selected from C1-C3; R 2 One selected from a C1-C12 divalent alkyl group, a C1-C12 divalent alkenyl group, and a C1-C12 divalent alkoxy group.

6. A method for preparing a low surface energy macromolecular photoinitiator, characterized in that: The steps include: A small molecule ultraviolet light initiator is reacted with a diamine molecule in a first solvent, and an intermediate is obtained by filtering and drying; The intermediate is reacted with polydimethylsiloxane having a blocking group in a second solvent, and filtered and dried to obtain a low surface energy macromolecular photoinitiator, wherein the blocking group includes at least one of a hydroxyl group, an epoxy group, and an amino group; Alternatively, the intermediate is reacted with perfluoropolyether diol in a second solvent, and the low surface energy macromolecular photoinitiator is obtained by filtering and drying.

7. A UV LED light-curing coating, characterized in that: The invention comprises the low surface energy macromolecular photoinitiator as described in any one of claims 1 to 6.

8. The UV LED light-curing coating according to claim 7, characterized in that: UV LED light curing coatings include: Acrylate monomer, 10-40wt%; UV curing resin, 20-60wt%; Crosslinking agent, 5-30wt%; The content of the low surface energy macromolecular photoinitiator is 1.0-10.0 wt%.

9. The UV LED light-curing coating according to claim 8, characterized in that: The UV curable resin is selected from one or a combination of polyester polyurethane acrylate, polyether polyurethane acrylate, polyester acrylate and polyether acrylate; and / or, The crosslinking agent is selected from one of trifunctional acrylate, tetrafunctional acrylate, pentafunctional acrylate and hexafunctional acrylate or a combination thereof.

10. A light-cured skin-feel coating, characterized in that: The photocurable skin-feel coating is obtained by curing the UV LED photocurable coating according to any one of claims 7 to 9 with ultraviolet light.

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