Solvent-free environment-friendly UV (ultraviolet) fast curing coating as well as preparation method and application thereof

Abstract

The invention provides a solvent-free environment-friendly UV (ultraviolet) fast curing coating as well as a preparation method and application thereof. The solvent-free environment-friendly UV fast curing coating is prepared from raw materials including UV fast curing resin, the UV fast curing resin is prepared from the following raw materials: hydroxyl-terminated branched saturated polyester, hydroxyethyl methylacrylate, isocyanate, 2-(2-ethoxyethoxy) ethyl acrylate, acryloyl morpholine, a catalyst and a photoinitiator. According to the solvent-free environment-friendly UV fast curing coating provided by the invention, as a pencil coating, the UV fast curing resin is introduced, and an ultraviolet curing process is adopted, so that the emission of VOC (Volatile Organic Compounds) is greatly reduced, and the solvent-free environment-friendly UV fast curing coating is environment-friendly; the storage and use processes are safer; the coating frequency is reduced, the energy consumption is reduced, the production efficiency is improved, and energy conservation and emission reduction are promoted; the curing film-forming molecular weight is large, the pigment and filler dispersing and wrapping performance is good, and the wear resistance, the weather resistance, the chemical resistance and other performance are all greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of pencil coatings, and relates to a solvent-free, environment-friendly UV fast-curing coating, a preparation method and application thereof, and specifically relates to a solvent-free, environment-friendly UV fast-curing coating for pencils with special visual and tactile effects, a preparation method and an application method thereof. Background Art

[0002] Pencil coating is a very important part of pencil manufacturing. It not only protects the pencil lead, but also makes the pencil more beautiful.

[0003] Currently, pencil coatings on the market are basically nitro paint and water-based paint. Nitro pencil coating has a relatively low solid content, which means that multiple coatings are required during the coating process to achieve the ideal coating thickness and effect. Nitro pencil coatings perform generally in terms of weather resistance and chemical resistance. When exposed to harsh environments such as sunlight, rain or chemicals for a long time, the coating may fade, crack or peel, which will affect the appearance and service life of the pencil. The solvent content in nitro pencil coating is relatively large, resulting in a high content of volatile organic compounds (VOCs). These VOCs are released into the air during the coating and drying process, causing pollution to the environment. In addition, VOCs may also have adverse effects on human health, such as irritation to the eyes, nose and throat. The main ingredients of nitro pencil coatings include flammable substances such as nitrocellulose. Once exposed to open flames or high temperature environments, the coating may cause dangerous situations such as combustion or explosion.

[0004] Water-based pencil paint takes a long time to dry, especially in low temperature and high humidity environments, which will affect production efficiency. Water is not easy to volatilize, and more heat is needed to dry the paint film. Due to the long drying time, more water will remain in the pencil, resulting in a soft paint film, poor wear resistance, and easy cracking of the pencil. Water-based pencil paint requires a smaller amount of paint and requires multiple coatings to achieve fullness, which affects production efficiency; water-based pencil paint has certain requirements for the temperature and humidity of the construction environment, and the construction environment needs to be strictly controlled during the construction process.

[0005] Therefore, in the art, it is desirable to develop a pencil coating which is not only environmentally friendly, but also has a fast curing speed and a small number of coatings, and can solve the problems of nitro pencil coatings and water-based pencil coatings having soft paint films, poor abrasion resistance, weather resistance, and chemical resistance. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a solvent-free, environmentally friendly UV fast-curing coating and a preparation method and application thereof, and specifically to provide a solvent-free, environmentally friendly UV fast-curing coating for pencils with special visual and tactile effects and a preparation method and application method thereof.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a solvent-free, environmentally friendly, UV fast-curing coating, wherein the raw materials for preparing the solvent-free, environmentally friendly, UV fast-curing coating include a UV fast-curing resin;

[0009] The raw materials for preparing the UV fast curing resin include the following components in parts by weight:

[0010] 20-30 parts of hydroxyl-terminated branched saturated polyester;

[0011] 15-20 parts of hydroxyethyl methacrylate;

[0012] 30-40 parts of isocyanate;

[0013] 2-(2-ethoxyethoxy)ethyl acrylate 10-20 parts;

[0014] Acryloylmorpholine 2-5 parts;

[0015] 0.1-0.5 parts of organic bismuth catalyst;

[0016] 1-3 parts of photoinitiator.

[0017] The solvent-free environmentally friendly UV fast-curing coating provided by the invention is used as pencil coating. By introducing UV fast-curing resin, the problem of large VOC emission of nitro pencil coating is solved, the harm to human health is greatly reduced, storage and construction are safer, and the problems of soft paint film, poor wear resistance, weather resistance and chemical resistance of nitro pencil coating and water-based pencil coating are solved, and the problems of many coating times and low production efficiency of nitro pencil coating and water-based pencil coating are solved.

[0018] The invention chemically synthesizes a UV fast-curing resin specially used for pencil paint, and is used for preparing pencil paint with special visual and tactile effects. The resin has fast curing speed, high glossiness, good dispersion effect on pigments and fillers, and paint film performance is significantly better than water-based and oil-based pencil paints on the market; compared with water-based and oil-based pencil paints, the weather resistance, chemical resistance, strength, toughness and other properties of the paint film are greatly improved.

[0019] In the present invention, the "fast curing" in the "UV fast curing coating" and "UV fast curing resin" means that the coating or resin can be cured within 8-12 seconds.

[0020] In the present invention, the raw materials for preparing the UV fast curing resin are calculated by weight, and the amount of the terminal hydroxyl branched saturated polyester can be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, etc.

[0021] In the present invention, the raw materials for preparing the UV fast curing resin are calculated by weight, and the amount of hydroxyethyl methacrylate can be 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc.

[0022] In the present invention, the raw materials for preparing the UV fast curing resin are calculated by weight, and the amount of isocyanate used can be 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, etc.

[0023] In the present invention, the raw materials for preparing the UV fast curing resin are calculated by weight, and the amount of 2-(2-ethoxyethoxy)ethyl acrylate can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc.

[0024] In the present invention, the raw materials for preparing the UV fast curing resin are calculated by weight, and the amount of acryloylmorpholine used can be 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0025] In the present invention, the raw materials for preparing the UV fast curing resin are calculated by weight, and the amount of the organic bismuth catalyst used can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, etc.

[0026] In the present invention, the raw materials for preparing the UV fast curing resin are measured by weight, and the amount of the photoinitiator used can be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, 3 parts, etc.

[0027] Preferably, the isocyanate comprises hexamethylene diisocyanate.

[0028] Preferably, the photoinitiator comprises 1173 photoinitiator.

[0029] Preferably, the UV fast curing resin is prepared by the following method:

[0030] (1) Adding the terminal hydroxyl branched saturated polyester into a reaction kettle, heating, and vacuuming to remove the moisture therein;

[0031] (2) Cooling down, filling the reactor with inert gas, then adding isocyanate to react, and then adding an organic bismuth catalyst to continue the reaction;

[0032] (3) Adding hydroxyethyl methacrylate into the reaction kettle, continuing the reaction, increasing the temperature, and maintaining the temperature;

[0033] (4) Cooling the mixture, adding 2-(2-ethoxyethoxy)ethyl acrylate, acryloylmorpholine, and a photoinitiator, and stirring the mixture to obtain the UV fast-curing resin.

[0034] Preferably, the heating in step (1) is heating to 100-110°C, for example, 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, etc.

[0035] Preferably, the vacuuming time in step (1) is 0.5-1.5 hours, for example, 0.5 hours, 1 hour, 1.5 hours, etc.

[0036] Preferably, the cooling in step (2) is to cool to 60-70°C, such as 60°C, 65°C, 70°C, etc.

[0037] Preferably, the inert gas in step (2) comprises nitrogen.

[0038] Preferably, the reaction time of step (2) is 15-25 minutes, for example, 15 minutes, 20 minutes, 25 minutes, etc.

[0039] Preferably, the reaction time in step (2) is 0.5-1.5 hours, for example, 0.5 hours, 1 hour, 1.5 hours, etc.

[0040] Preferably, the reaction time in step (3) is 20-40 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, etc.

[0041] Preferably, the temperature in step (3) is increased to 80-85°C, such as 80°C, 83°C, 85°C, etc.

[0042] Preferably, the insulation time in step (3) is 0.5-1.5 hours, for example, 0.5 hours, 1 hour, 1.5 hours, etc.

[0043] Preferably, the cooling in step (4) is to a temperature of 35-45°C, such as 35°C, 40°C, 45°C, etc.

[0044] Preferably, the stirring time in step (4) is 20-40 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, etc.

[0045] Preferably, the raw materials for preparing the solvent-free environmentally friendly UV fast-curing coating also include auxiliary agents.

[0046] Preferably, the auxiliary agent includes any one of a feel agent, a leveling agent, a defoaming agent, and a dispersant, or a combination of at least two of them.

[0047] Preferably, the feel agent comprises silicone resin.

[0048] Preferably, the leveling agent comprises polydimethylsiloxane.

[0049] Preferably, the defoaming agent comprises a modified polysiloxane defoaming agent.

[0050] Preferably, the dispersant comprises polyacrylamide.

[0051] Preferably, the raw materials for preparing the solvent-free environmentally friendly UV fast curing coating include the following components in parts by weight:

[0052] 80-90 parts of UV fast curing resin;

[0053] 0.1-1 part of hand feeling agent;

[0054] Leveling agent 0.2-1 part;

[0055] Defoaming agent 0.2-1 part;

[0056] Dispersant 0.1-0.5 parts.

[0057] Preferably, the raw materials for preparing the solvent-free, environmentally friendly UV fast-curing coating are calculated by weight, and the amount of UV fast-curing resin used can be 80 parts, 81 parts, 82 parts, 83 parts, 84 parts, 85 parts, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts, etc.

[0058] Preferably, the raw materials for preparing the solvent-free environmentally friendly UV fast-curing coating are calculated by weight, and the amount of the hand feeling agent used can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part, 1 part, etc.

[0059] Preferably, the raw materials for preparing the solvent-free environmentally friendly UV fast-curing coating are measured by weight, and the amount of the leveling agent used can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, etc.

[0060] Preferably, the raw materials for preparing the solvent-free, environmentally friendly UV fast-curing coating are measured by weight, and the amount of the defoaming agent used can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part, etc.

[0061] Preferably, the amount of the dispersant used in the preparation of the solvent-free, environmentally friendly UV fast-curing coating can be 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, etc., based on the weight parts of the raw materials.

[0062] Preferably, the raw materials for preparing the solvent-free environmentally friendly UV fast-curing coating further include any one of glass-coated silver powder, pearlescent pigment, and aluminum powder, or a combination of at least two of them.

[0063] Preferably, the glass-coated silver powder is glass-coated silver flakes.

[0064] Preferably, the weight proportion of the glass-coated silver powder is 3-6 parts, for example, 3 parts, 4 parts, 5 parts, 6 parts, etc.

[0065] Preferably, the pearlescent pigment is mica flakes coated with metal oxides.

[0066] Preferably, the weight proportion of the pearlescent pigment is 3-6 parts, such as 3 parts, 4 parts, 5 parts, 6 parts, etc.

[0067] Preferably, the aluminum powder is a resin-coated aluminum sheet.

[0068] Preferably, the weight proportion of the aluminum powder is 1-3 parts, such as 1 part, 2 parts, 3 parts, etc.

[0069] Preferably, the raw materials for preparing the solvent-free environmentally friendly UV fast-curing coating also include 1-3 parts (eg, 1 part, 2 parts, 3 parts, etc.) of color powder.

[0070] In a second aspect, the present invention provides a method for preparing the solvent-free, environmentally friendly UV fast-curing coating as described in the first aspect, the preparation method comprising the following steps:

[0071] UV fast-curing resin, defoamer, leveling agent and dispersant are added into a dispersion kettle and stirred, and then glass-coated silver powder, pearlescent pigment, aluminum powder, color powder and hand-feeling agent are added and stirred again to obtain the solvent-free environmentally friendly UV fast-curing coating.

[0072] Preferably, the stirring temperature is 10-40°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc.

[0073] Preferably, the stirring speed is 600-800 rpm, for example, 600 rpm, 650 rpm, 700 rpm, 750 rpm, 800 rpm, etc.

[0074] Preferably, the stirring time is 15-25 minutes, for example 15 minutes, 20 minutes, 25 minutes, etc.

[0075] Preferably, the rotation speed of the second stirring is 300-500 rpm, for example, 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, etc.

[0076] Preferably, the re-stirring time is 25-35 minutes, such as 25 minutes, 30 minutes, 35 minutes, etc.

[0077] In a second aspect, the present invention provides an application of the solvent-free, environmentally friendly UV fast-curing coating as described in the first aspect in pencil coating, wherein the application method comprises the following steps:

[0078] Use a pencil coating machine to apply UV-curable color paint on the surface of the pencil original rod through a pumping process, each coating thickness is 4-6 microns (for example, 4 microns, 4.5 microns, 5 microns, 5.5 microns, 6 microns), and transfer it to the UV curing machine through a conveyor belt for curing for 8-12 seconds (for example, 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, etc.), repeat the coating and curing 4-6 times, and then pump-coat the surface with UV-curable light paint once, and cure it for 8-12 seconds (for example, 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, etc.), to obtain a pencil with pearlescent and / or metallic special effects;

[0079] Among them, the UV light curing paint is the solvent-free environmentally friendly UV fast curing coating described in the first aspect, and the solvent-free environmentally friendly UV fast curing coating includes color powder, and any one or a combination of at least two of glass-coated silver powder, pearlescent pigment, and aluminum powder. The difference between the UV light curing paint and the UV light curing paint is that the UV light curing paint does not contain glass-coated silver powder, pearlescent pigment, aluminum powder, and color powder.

[0080] The solvent-free, environment-friendly UV fast-curing coating provided by the present invention is used as pencil coating, which can bring special visual and tactile effects to pencils. It is different from the oily and water-based coatings for pencils on the market, makes up for the shortcomings of oily and water-based coatings, and achieves special visual (shimmering, color-changing, metallic pearlescent, etc.) and tactile (skin-friendly, soft, etc.) effects.

[0081] In the present invention, the UV-curing painting process greatly reduces VOC emissions, reduces energy consumption, and improves production efficiency compared to the thermal curing process of water-based and oil-based paints, which is of great significance to energy conservation and emission reduction. Due to the extremely low volatility of UV-curing paints, the harm to operators is greatly reduced compared to oil-based paints.

[0082] Preferably, in the application method, after applying a UV-curing varnish once on the surface, the method further comprises the following steps:

[0083] A UV-curable paint with another appearance effect is placed in a container, and one end of the pencil is coated with the paint by dipping, with a length of 25-35 mm (e.g., 25 mm, 28 mm, 30 mm, 32 mm, 33 mm, 35 mm, etc.), and then conveyed to a UV curing machine by a conveyor belt for curing for 8-12 seconds (e.g., 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, etc.), and then a layer of UV-curable paint is coated on the surface by pumping, and cured for 8-12 seconds (e.g., 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, etc.), to obtain a pencil with other pearlescent and / or metallic effects. Among them, the difference between the UV-curable paint with another appearance effect and the UV-curable paint mentioned above is that the added color powder, glass-coated silver powder, pearlescent pigment, aluminum powder, etc. are different in type.

[0084] Compared with the prior art, the present invention has the following beneficial effects:

[0085] The solvent-free environmentally friendly UV fast-curing coating provided by the present invention is used as a pencil coating. By introducing a UV fast-curing resin and adopting an ultraviolet curing process, VOC emissions are greatly reduced, and the coating is environmentally friendly; it is safer during storage and use; the number of coatings is reduced, energy consumption is reduced, production efficiency is improved, and energy conservation and emission reduction are promoted; the cured film-forming molecular weight is large, and the dispersion and encapsulation of pigments and fillers are good. Compared with oil-based and water-based pencil coatings, the wear resistance, weather resistance, chemical resistance and other properties are greatly improved; when used as a pencil coating, it can bring special visual (shimmering, color-changing, metallic pearlescent, etc.) and tactile (skin-friendly, soft, etc.) effects. DETAILED DESCRIPTION

[0086] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0087] Unless otherwise specified, some of the raw material information used in the preparation examples or embodiments of the present invention is as follows:

[0088] Hydroxyl-terminated branched saturated polyester: PA245;

[0089] Organic bismuth catalyst: BiCAT8118;

[0090] Defoaming agent: YCK750;

[0091] Leveling agent: YCK1130;

[0092] Dispersant: BYK145;

[0093] Feeling agent: SY5370.

[0094] Preparation Example 1

[0095] In this preparation example, a UV fast curing resin is provided, and the preparation method comprises the following steps:

[0096] (1) Add 20 parts of terminal hydroxyl branched saturated polyester into a reaction kettle, heat to 100°C, and use a vacuum pump to evacuate for 1 hour to remove the moisture therein;

[0097] (2) Cooling to 65° C., filling the reactor with nitrogen, slowly adding 32 parts of hexamethylene diisocyanate into the reactor while stirring, and reacting for 20 minutes; after 20 minutes, adding 0.2 parts of an organic bismuth catalyst dropwise into the reactor, and continuing the reaction for 1 hour;

[0098] (3) 15 parts of hydroxyethyl methacrylate was added to the reactor, and the reaction was continued for 30 minutes. Then the temperature was raised to 83°C and kept at this temperature for 1 hour;

[0099] (4) The temperature was lowered to 40° C., 12 parts of 2-(2-ethoxyethoxy)ethyl acrylate, 2 parts of acryloylmorpholine, and 1 part of 1173 photoinitiator were added to the reaction kettle, and stirred for 30 minutes to obtain the UV fast curing resin.

[0100] Preparation Example 2

[0101] In this preparation example, a UV fast curing resin is provided, and the preparation method comprises the following steps:

[0102] (1) 22 parts of terminal hydroxyl branched saturated polyester were added to a reaction kettle, heated to 100° C., and vacuumed for 1 hour using a vacuum pump to remove moisture therein;

[0103] (2) Cooling to 60°C, filling the reactor with nitrogen, slowly adding 35 parts of hexamethylene diisocyanate into the reactor while stirring, and reacting for 20 minutes; after 20 minutes, adding 0.3 parts of an organic bismuth catalyst dropwise into the reactor, and continuing the reaction for 1 hour;

[0104] (3) 18 parts of hydroxyethyl methacrylate was added to the reactor, and the reaction was continued for 30 minutes. Then the temperature was raised to 80°C and kept at this temperature for 1 hour;

[0105] (4) The temperature was lowered to 40° C., 14 parts of 2-(2-ethoxyethoxy)ethyl acrylate, 2 parts of acryloylmorpholine, and 1.6 parts of 1173 photoinitiator were added to the reaction kettle, and stirred for 30 minutes to obtain the UV fast curing resin.

[0106] Preparation Example 3

[0107] In this preparation example, a UV fast curing resin is provided, and the preparation method comprises the following steps:

[0108] (1) 25 parts of terminal hydroxyl branched saturated polyester were added to a reaction kettle, heated to 100° C., and vacuumed for 1 hour using a vacuum pump to remove moisture therein;

[0109] (2) Cooling to 70°C, filling the reactor with nitrogen, slowly adding 35 parts of hexamethylene diisocyanate into the reactor while stirring, and reacting for 20 minutes; after 20 minutes, adding 0.5 parts of an organic bismuth catalyst dropwise into the reactor, and continuing the reaction for 1 hour;

[0110] (3) Add 20 parts of hydroxyethyl methacrylate into the reactor and continue the reaction for 30 minutes. Then raise the temperature to 85°C and keep it for 1 hour.

[0111] (4) The temperature was lowered to 40° C., 15 parts of 2-(2-ethoxyethoxy)ethyl acrylate, 5 parts of acryloylmorpholine, and 2 parts of 1173 photoinitiator were added to the reaction kettle, and stirred for 30 minutes to obtain the UV fast curing resin.

[0112] Preparation Example 4

[0113] In this preparation example, a UV fast curing resin is provided, and the preparation method comprises the following steps:

[0114] (1) 30 parts of terminal hydroxyl branched saturated polyester were added to a reaction kettle, heated to 100° C., and vacuumed for 1 hour using a vacuum pump to remove moisture therein;

[0115] (2) Cooling to 65° C., filling the reactor with nitrogen, slowly adding 34 parts of hexamethylene diisocyanate into the reactor while stirring, and reacting for 20 minutes; after 20 minutes, adding 0.2 parts of an organic bismuth catalyst dropwise into the reactor, and continuing the reaction for 1 hour;

[0116] (3) 15 parts of hydroxyethyl methacrylate was added to the reactor, and the reaction was continued for 30 minutes. Then the temperature was raised to 82°C and kept at this temperature for 1 hour;

[0117] (4) The temperature was lowered to 40° C., 20 parts of 2-(2-ethoxyethoxy)ethyl acrylate, 5 parts of acryloylmorpholine, and 2 parts of 1173 photoinitiator were added to the reaction kettle, and stirred for 30 minutes to obtain the UV fast curing resin.

[0118] Comparative Preparation Example 1

[0119] The only difference between this comparative preparation example and preparation example 1 is that in step (4), 2-(2-ethoxyethoxy)ethyl acrylate is replaced by an equal weight portion of isobornyl methacrylate.

[0120] Comparative Preparation Example 2

[0121] The only difference between this comparative preparation example and preparation example 1 is that acryloylmorpholine is not added in step (4).

[0122] Example 1-A

[0123] In this embodiment, a solvent-free, environmentally friendly UV fast-curing coating is provided, and the preparation method comprises the following steps:

[0124] At 25°C, the stirring speed is 700 rpm, 85 parts of UV fast curing resin, 0.2 parts of defoaming agent, 1 part of leveling agent, and 0.2 parts of dispersant are added to the dispersion kettle in sequence and stirred. After stirring for 20 minutes, 3 parts of glass-coated silver powder, 3 parts of pearlescent pigment, 1 part of aluminum powder, 2 parts of color powder, and 0.5 parts of hand feeling agent are added under the stirring condition of 400 rpm and stirred for 30 minutes;

[0125] The UV fast-curing resin is provided by Preparation Example 1, the glass-coated silver powder is U3500, the pearlescent pigment is SCL305, the aluminum powder is NPW2600, and the color powder is transparent blue 737.

[0126] Example 1-B

[0127] The only difference between this embodiment and embodiment 1-A is that glass-coated silver powder, pearlescent pigment, aluminum powder and color powder are not added.

[0128] Example 2-A

[0129] In this embodiment, a solvent-free, environmentally friendly UV fast-curing coating is provided, and the preparation method comprises the following steps:

[0130] At 25°C, with a stirring speed of 600 rpm, 90 parts of UV fast curing resin, 0.3 parts of defoaming agent, 0.5 parts of leveling agent, and 0.1 parts of dispersant were sequentially added into the dispersion kettle for stirring. After stirring for 20 minutes, 5 parts of glass-coated silver powder, 6 parts of pearlescent pigment, 1.5 parts of aluminum powder, 2 parts of color powder, and 0.8 parts of hand feeling agent were added at a stirring speed of 300 rpm and stirred for 30 minutes.

[0131] The UV fast-curing resin is provided by Preparation Example 2, the glass-coated silver powder is U3500, the pearlescent pigment is SCL305, the aluminum powder is NPW2600, and the color powder is transparent purple 840.

[0132] Example 2-B

[0133] The only difference between this embodiment and embodiment 2-A is that glass-coated silver powder, pearlescent pigment, aluminum powder and color powder are not added.

[0134] Example 3-A

[0135] In this embodiment, a solvent-free, environmentally friendly UV fast-curing coating is provided, and the preparation method comprises the following steps:

[0136] At 25°C, the stirring speed is 800 rpm, 82 parts of UV fast curing resin, 0.5 parts of defoaming agent, 0.8 parts of leveling agent, and 0.5 parts of dispersant are added to the dispersion kettle in sequence and stirred. After stirring for 20 minutes, 6 parts of glass-coated silver powder, 4 parts of pearlescent pigment, 2 parts of aluminum powder, 2 parts of color powder, and 0.3 parts of hand feeling agent are added under the stirring condition of 500 rpm and stirred for 30 minutes;

[0137] The UV fast-curing resin is provided by Preparation Example 3, the glass-coated silver powder is U3500, the pearlescent pigment is SCL305, the aluminum powder is NPW2600, and the color powder is transparent yellow 8802.

[0138] Example 3-B

[0139] The only difference between this embodiment and embodiment 3-A is that glass-coated silver powder, pearlescent pigment, aluminum powder and color powder are not added.

[0140] Example 4-A

[0141] In this embodiment, a solvent-free, environmentally friendly UV fast-curing coating is provided, and the preparation method comprises the following steps:

[0142] At 25°C, the stirring speed is 800 rpm, 88 parts of UV fast curing resin, 0.2 parts of defoaming agent, 0.6 parts of leveling agent, and 0.3 parts of dispersant are added to the dispersion kettle in sequence and stirred. After stirring for 20 minutes, 3 parts of glass-coated silver powder, 5 parts of pearlescent pigment, 1 part of aluminum powder, 2 parts of color powder, and 0.5 parts of hand feeling agent are added under the stirring condition of 500 rpm and stirred for 30 minutes;

[0143] The UV fast-curing resin is provided by Preparation Example 4, the glass-coated silver powder is U3500, the pearlescent pigment is SCL305, the aluminum powder is NPW2600, and the color powder is transparent green 852.

[0144] Example 4-B

[0145] The only difference between this embodiment and embodiment 4-A is that glass-coated silver powder, pearlescent pigment, aluminum powder and color powder are not added.

[0146] Comparative Example 1-A

[0147] The only difference between this comparative example and Example 1-A is that the UV fast curing resin is provided by Comparative Preparation Example 1.

[0148] Comparative Example 1-B

[0149] The only difference between this comparative example and comparative example 1-A is that no glass-coated silver powder, pearlescent pigment, aluminum powder, or color powder is added.

[0150] Comparative Example 2-A

[0151] The only difference between this comparative example and Example 1-A is that the UV fast curing resin is provided by Comparative Preparation Example 2.

[0152] Comparative Example 2-B

[0153] The only difference between this comparative example and comparative example 2-A is that no glass-coated silver powder, pearlescent pigment, aluminum powder, or color powder is added.

[0154] Application Example 1

[0155] Using a pencil coating machine, the ultraviolet light curing color paint (i.e., the solvent-free environmentally friendly UV fast curing paint provided in Example 1-A) is coated on the surface of the pencil original rod by a pumping process, each coating film thickness is 5 microns, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds. The coating and curing are repeated 5 times, and finally, the ultraviolet light curing varnish (i.e., the solvent-free environmentally friendly UV fast curing paint provided in Example 1-B) is pumped on the surface once, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds to obtain a pencil with blue pearlescent and metallic flash special effects.

[0156] Application Example 2

[0157] Using a pencil coating machine, the ultraviolet light curing color paint (i.e., the solvent-free environmentally friendly UV fast curing paint provided in Example 2-A) is coated on the surface of the pencil original rod by a pumping process, each coating film thickness is 5 microns, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds. The coating and curing are repeated 5 times, and finally, the ultraviolet light curing varnish (i.e., the solvent-free environmentally friendly UV fast curing paint provided in Example 2-B) is pumped on the surface once, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds to obtain a pencil with purple pearlescent and metallic flash special effects.

[0158] Application Example 3

[0159] Using a pencil coating machine, the ultraviolet light curing color paint (i.e., the solvent-free environmentally friendly UV fast curing paint provided in Example 3-A) is coated on the surface of the pencil original rod by a draw coating process, each coating film thickness is 5 microns, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds. The coating and curing are repeated 5 times, and finally, the ultraviolet light curing varnish (i.e., the solvent-free environmentally friendly UV fast curing paint provided in Example 3-B) is drawn on the surface once, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds to obtain a pencil with yellow pearlescent and metallic flash special effects.

[0160] Application Example 4

[0161] Using a pencil coating machine, a UV-curable color paint (i.e., the solvent-free, environmentally friendly UV fast-curing paint provided in Example 4-A) is applied to the surface of the pencil rod by a pumping process, each coating film thickness is 5 μm, and the paint is transferred to the UV curing machine through a conveyor belt for curing for 10 seconds, and the coating and curing are repeated 5 times, and finally, a UV-curable varnish (i.e., the solvent-free, environmentally friendly UV fast-curing paint provided in Example 4-B) is pumped on the surface once, and the paint is transferred to the UV curing machine through a conveyor belt for curing for 10 seconds, to obtain a pencil with green pearlescent and metallic flash special effects;

[0162] Another UV-curable color paint with an appearance effect (i.e., the solvent-free, environmentally friendly UV fast-curing paint provided in Example 1-A) is placed in a tray, and one end of the pencil is coated with the paint by a dipping process, with a length of 25 mm, and then conveyed to a UV curing machine by a conveyor belt for curing for 10 seconds, and then a layer of UV-curable varnish (i.e., the solvent-free, environmentally friendly UV fast-curing paint provided in Example 1-B) is coated on the surface by a draw coating process, and conveyed to a UV curing machine by a conveyor belt for curing for 10 seconds, to obtain a pencil partially having another blue pearlescent and metallic glitter special effects.

[0163] Comparative application example 1

[0164] A pencil coating machine is used to apply ultraviolet light-curing color paint (i.e., the solvent-free, environmentally friendly UV fast-curing paint provided in Comparative Example 1-A) on the surface of the pencil original rod by a draw coating process, each coating film thickness is 5 microns, and the paint is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds, and the coating and curing are repeated 5 times. Finally, ultraviolet light-curing varnish (i.e., the solvent-free, environmentally friendly UV fast-curing paint provided in Comparative Example 1-B) is drawn on the surface once, and the paint is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds, thereby obtaining a pencil with blue pearlescent and metallic flash special effects.

[0165] Comparative Application Example 2

[0166] Using a pencil coating machine, the ultraviolet light curing color paint (i.e. the solvent-free environmentally friendly UV fast curing paint provided in Comparative Example 2-A) is coated on the surface of the pencil original rod by a draw coating process, each coating film thickness is 5 microns, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds, and the coating and curing are repeated 5 times. Finally, the ultraviolet light curing varnish (i.e. the solvent-free environmentally friendly UV fast curing paint provided in Comparative Example 2-B) is drawn on the surface once, and it is transferred to the ultraviolet curing machine through a conveyor belt for curing for 10 seconds to obtain a pencil with blue pearlescent and metallic flash special effects.

[0167] The performance of the pencils in the corresponding use cases and comparative application examples was tested (since the coating of the pencils came from the examples, the coatings provided in Examples 1-B to 4-B, Comparative Example 1-B, and Comparative Example 2-B were actually tested), and the test method was as follows:

[0168] (1) Pencil paint film hardness: Use a 15 μm film maker to scrape the paint onto a glass plate, cure it in a UV curing machine for 10 seconds, and then use a 1 kg weighted pencil hardness tester to test the pencil paint film hardness;

[0169] (2) Cracking rate: Use a 15-micron film-making device to scrape the paint onto a polished basswood board, cure it in a UV curing machine for 10 seconds, and then place it in a constant temperature and humidity chamber at 45°C and 80% humidity for 15 days to observe the degree of cracking of the paint film.

[0170] (3) Solvent resistance: Use a 15-micron film-making device to scrape the paint onto a glass plate, cure it in a UV curing machine for 10 seconds, wipe it with gauze soaked in butanone, and record the number of wipes when the paint film is damaged.

[0171] The performance test results are shown in Table 1.

[0172] Table 1

[0173]

[0174] It can be seen from Table 1 that the pencils prepared by using the solvent-free, environmentally friendly UV fast-curing coating provided by the embodiment of the present invention as pencil coating have a paint film with suitable hardness, good wear resistance, weather resistance and chemical resistance.

[0175] Compared with Application Example 1, the pencil provided in Comparative Application Example 1 is prone to cracking under high temperature and high humidity, causing irreversible damage to the pencil; the paint film of the pencil provided in Comparative Application Example 2 has low hardness and is easily scratched and damaged. When contaminated with oil, the paint film will swell and soften, resulting in color loss.

[0176] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the solvent-free environmentally friendly UV fast-curing coating and its preparation method and application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A solvent-free, environmentally friendly UV fast-curing coating, characterized in that: The raw materials for preparing the solvent-free environmentally friendly UV fast-curing coating include UV fast-curing resin; The raw materials for preparing the UV fast curing resin include the following components in parts by weight: 20-30 parts of hydroxyl-terminated branched saturated polyester; 15-20 parts of hydroxyethyl methacrylate; 30-40 parts of isocyanate; 2-(2-ethoxyethoxy)ethyl acrylate 10-20 parts; Acryloylmorpholine 2-5 parts; 0.1-0.5 parts of organic bismuth catalyst; 1-3 parts of photoinitiator.

2. The solvent-free, environmentally friendly UV fast curing coating according to claim 1, characterized in that: The isocyanate includes hexamethylene diisocyanate; The photoinitiator includes 1173 photoinitiator.

3. The solvent-free, environmentally friendly UV fast curing coating according to claim 1, characterized in that: The UV fast curing resin is prepared by the following method: (1) Adding the terminal hydroxyl branched saturated polyester into a reaction kettle, heating, and vacuuming to remove the moisture therein; (2) Cooling down, filling the reactor with inert gas, then adding isocyanate to react, and then adding an organic bismuth catalyst to continue the reaction; (3) Adding hydroxyethyl methacrylate into the reaction kettle, continuing the reaction, increasing the temperature, and maintaining the temperature; (4) Cooling the mixture, adding 2-(2-ethoxyethoxy)ethyl acrylate, acryloylmorpholine, and a photoinitiator, and stirring the mixture to obtain the UV fast-curing resin.

4. The solvent-free, environmentally friendly UV fast curing coating according to claim 3, characterized in that: The heating in step (1) is heating to 100-110° C. The vacuuming time in step (1) is 0.5-1.5 hours; The cooling in step (2) is to cool to 60-70°C; The reaction time of step (2) is 15-25 minutes; The reaction time in step (2) is 0.5-1.5 hours; The reaction time in step (3) is 20-40 minutes; The heating in step (3) is to heat the temperature to 80-85°C; The insulation time in step (3) is 0.5-1.5 hours; The cooling in step (4) is to cool to 35-45°C; The stirring time in step (4) is 20-40 minutes.

5. The solvent-free, environmentally friendly UV fast curing coating according to claim 1, characterized in that: The raw materials for preparing the solvent-free environmentally friendly UV fast curing coating also include auxiliary agents; The auxiliary agent includes any one or a combination of at least two of a feel agent, a leveling agent, a defoamer, and a dispersant; The hand feeling agent includes silicone resin; The leveling agent includes polydimethylsiloxane; The defoamer comprises a modified polysiloxane defoamer; The dispersant includes polyacrylamide.

6. The solvent-free, environmentally friendly UV fast curing coating according to claim 5, characterized in that: The raw materials for preparing the solvent-free environmentally friendly UV fast curing coating include the following components in parts by weight: 80-90 parts of UV fast curing resin; 0.1-1 part of hand feeling agent; Leveling agent 0.2-1 part; Defoaming agent 0.2-1 part; Dispersant 0.1-0.5 parts.

7. The solvent-free, environmentally friendly UV fast-curing coating according to claim 6, characterized in that: The raw materials for preparing the solvent-free environmentally friendly UV fast curing coating also include any one of glass-coated silver powder, pearlescent pigment, and aluminum powder, or a combination of at least two of them; The glass-coated silver powder is a glass-coated silver sheet; The weight proportion of the glass-coated silver powder is 3-6 parts; The pearlescent pigment is a mica flake coated with a metal oxide; The weight proportion of the pearlescent pigment is 3-6 parts; The aluminum powder is a resin-coated aluminum sheet; The weight proportion of the aluminum powder is 1-3 parts; The raw materials for preparing the solvent-free environmentally friendly UV fast-curing coating also include 1-3 parts of color powder.

8. A method for preparing a solvent-free, environmentally friendly UV fast-curing coating as claimed in claim 7, characterized in that: The preparation method comprises the following steps: UV fast-curing resin, defoamer, leveling agent and dispersant are added into a dispersion kettle and stirred, and then glass-coated silver powder, pearlescent pigment, aluminum powder, color powder and hand-feeling agent are added and stirred again to obtain the solvent-free environmentally friendly UV fast-curing coating.

9. The preparation method according to claim 8, characterized in that: The stirring temperature is 10-40°C; The stirring speed is 600-800 rpm; The stirring time is 15-25 minutes; The rotation speed of the second stirring is 300-500 rpm; The stirring time is 25-35 minutes.

10. Application of the solvent-free, environmentally friendly UV fast curing coating as claimed in claim 7 in pencil coating, characterized in that: The method of application comprises the following steps: Using a pencil coating machine, a UV-curable color paint is applied to the surface of the pencil original rod by a pumping process, each coating film thickness is 4-6 microns, and then the paint is transferred to the UV curing machine through a conveyor belt for curing for 8-12 seconds, and the coating and curing are repeated 4-6 times, and then a UV-curable varnish is pumped on the surface once and cured for 8-12 seconds to obtain a pencil with pearlescent and / or metallic special effects; Wherein, the UV-curable paint is the solvent-free environmentally friendly UV fast-curing paint as described in claim 7, and the difference between the UV-curable paint and the UV-curable paint is that the UV-curable paint does not contain glass-coated silver powder, pearlescent pigment, aluminum powder, and color powder; In the application method, after applying a UV-curing varnish once on the surface, the following steps are also included: A UV-curable color paint with another appearance effect is placed in a container, and one end of the pencil is coated with the paint by a dipping process, with a length of 25-35 mm, and then conveyed to a UV curing machine by a conveyor belt for curing for 8-12 seconds, and then a layer of UV-curable varnish is coated on the surface by a pumping process, and cured for 8-12 seconds, to obtain a pencil with other pearlescent and / or metallic special effects.

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