CN111320895A

CN111320895A - UV-LED curing inkjet ink and preparation method thereof

Info

Publication number: CN111320895A
Application number: CN201811544482.1A
Authority: CN
Inventors: 曹雷; 姚群; 李国栋; 李永生; 王静; 李栋
Original assignee: Lucky Huaguang Graphics Co Ltd
Current assignee: Lucky Huaguang Graphics Co Ltd
Priority date: 2018-12-17
Filing date: 2018-12-17
Publication date: 2020-06-23

Abstract

The invention discloses UV-LED curing ink-jet ink which comprises the following components in percentage by weight: 3-15% of polyester acrylate prepolymer, 3-15% of polyurethane acrylate prepolymer, 60-80% of active monomer, 1-5% of pigment, 3-15% of photoinitiator, 1-10% of co-initiator, 1-5% of phosphate ester, 3-15% of dispersant and 0.1-3% of auxiliary agent. The UV ink-jet ink provided by the invention does not contain an organic solvent, and has the characteristics of environmental protection; the printing ink can be instantly cured under the irradiation of an LED lamp, the appearance is not sticky, and the requirement of quick printing is met; the ink has good fluency; the hardness is moderate, and the scratch resistance is realized; the adhesive force with the base material is good; the ink is boiling resistant, is used for variable data printing of metal cans, and has wide development prospect.

Description

UV-LED curing inkjet ink and preparation method thereof

Technical Field

The invention belongs to the technical field of ink-jet ink, and particularly relates to UV-LED curing ink-jet ink and a preparation method thereof.

Background

With the social progress and the scientific and technological development, the functions of preservation, freshness preservation, safety and the like are required to be considered for the packaging of food and special chemicals in the food industry and the chemical industry, the original packaging box and common films cannot meet the requirements of transportation and storage, and the degradation capability of the films on the packaging box after use also determines that the packaging box is not suitable for the safe and environment-friendly idea of the modern society more and more, so that the food, beverage and special chemical packaging containers sold in the market at present are mainly made of two materials, namely metal and glass, and the glass is fragile, wherein the metal can packaging material has the characteristics of good tightness, hard texture, good elasticity, good light resistance and the like, and has an increasingly important position in the field of packaging of food and special chemicals. However, the metal cans have some defects that the metal cans are easy to rust and influence the quality of products, and the solution is to coat antirust coatings on the inner layer and the outer layer, because most of food cans are required to be sterilized at high temperature, the coatings are required to be resistant to high-temperature sterilization and cannot be dissolved out, and once the dissolution exceeds the standard, the quality of the products contained in the cans is influenced.

The production of metal film technology is a revolutionary progress of metal can production, the metal film technology is a processing technology for sticking a plastic film and a metal plate on the metal plate through high-temperature hot pressing, the film is produced in Japan in 1977, the metal film technology is initially used for can making and can replace an internal coating technology and an external coating technology, various fields such as building material internal installation, household appliance shell, ship internal installation and the like are developed so far, the film coating processing does not use adhesives and solvents, so formaldehyde is not contained, the plastic film can be treated by beautifying decoration, antibiosis, anti-dyeing and the like, the safety and health of a human body are ensured, meanwhile, the environment-friendly effect is achieved, the property change or the flavor change and the perforation of in-can chemical articles or food and beverage caused by the seepage of metal and paint dissolved from the metal plate can be avoided, and the film coating can be applied to the can making and packaging industry, and the metal film technology has a good development trend.

The metal can surface pattern printing mode adopts printing in the panel stage mostly, adopt modes such as offset printing, embossing, gravure and silk screen printing, system jar after the printing is accomplished, this kind of printing method is fit for the printing of big batch products, these printing modes adopt solvent type printing ink printing not environmental protection in some, do not accord with the environmental protection requirement, this kind of printing mode is high to the resistant temperature of adhesion of ink coating and resistant processing type simultaneously, there is the problem of pattern position deviation and damage pattern in the easy system jar in-process, the printing information is fixed information simultaneously, can not solve the problem of variable information.

The ink-jet digital printing process is directly carried out on the tank body, the problems can be solved, meanwhile, with the demand of people on material culture, personalized information needs to be added on the tank body, when product sales promotion is carried out, small batches of products are needed, different information patterns need to be added for different customers, an ink-jet digital printing unit is added in a tank manufacturing production line, the tank manufacturing and printing process can be completed simultaneously, the production process is simplified, the small-batch printing with personalized variable information is met, the personalized demand is increased, and the ink-jet digital printing process has a wide development prospect.

In the ink-jet printing and printing process, tiny ink fluid drops are directly sprayed onto the surface of an ink receiver, the printing and printing equipment and the ink receiver are not in physical contact, the printing and printing equipment electronically stores printing data, and controls a device (a spray head) to spray the ink-jet ink drops onto the ink receiver in an image mode, the printing mode comprises a scanning mode and an ONEPASS printing mode, the scanning mode is mainly used for industries such as advertising and publishing, the requirements on precision and color are high, the ONEPASS printing mode is mainly used for printing packaging materials such as labels and the like, the multi-injection reprinting speed industry is adopted, the requirements of the ONEPASS printing mode on ink are high in smoothness, and the requirements on high-speed printing and few printing strips are met.

Inkjet inks are an indispensable component of inkjet printing and printing, which is classified into water-based according to the drying mechanism involving absorption, permeation, and evaporation; oil-based, drying involving absorption and penetration; solvent-based, the drying mechanism of which involves mainly evaporation; thermal melting or phase change, where the ink is liquid at the jetting temperature and solid at room temperature, replaces drying by curing; UV curing, instead of drying, by polymerization. UV solidification is the photochemistry process, UV light energy is absorbed by photoinitiator in the UV printing ink binder, initiate the process that liquid active monomer or low polymerization form netted solid state macromolecule, UV photocuring inkjet ink has VOC zero release, low energy consumption, advantages such as green, be applicable to multiple stock, inkjet ink is not dry before UV light shines, can not produce the phenomenon of blockking up the shower nozzle because of ink solvent volatilizees, simultaneously UV inkjet prints owing to have and prints as required, high speed, high quality, low-cost advantage, more and more receive people's favor. The ultraviolet light source capable of causing UV curing was early mercury lamp, high-pressure or low-pressure mercury lamp, cold cathode tube, etc., and the emission wavelength was full band UVA, UVB, and UVC: UVA: 400 nm to 320 nm; UV-B: 320 nm to 290 nm; UVC: 290 nm to 100 nm, only a small part of the emitted light can be absorbed by a photoinitiator or a photoinitiator system in the irradiation curing process, the ineffective radiation of the light source accounts for 75 percent, most of the light is high-energy infrared light, a large amount of heat is generated to generate adverse effects on production control, meanwhile, the lamp contains heavy metals which are adverse to safety and environment protection, an ultraviolet light source UV-LED light source is gradually developed and matured in recent years, and an UVL-ED light source has multiple advantages compared with a mercury lamp, firstly, the radiation efficiency is greatly improved, and the effective utilization rate of light energy is improved by more than several times; the machine can be opened immediately without preheating; the service life is long. However, the method is different from the mercury lamp in that the wavelength peak emitted by the UV-LED light source is single, the wavelength of the common UV-LED light source is 395nm, the wavelength range is narrow, and the power and the irradiation are low compared with the mercury lamp, so that different requirements are imposed on the photoinitiation system of the matched ink.

When carrying out inkjet digital printing on the metallic tank, need satisfy the attached requirement of ink to metal and metal coating material, need carry out surface treatment, carry out the coating, processing such as corona or flame, increase technology complexity, corona and flame treatment also exert an influence to the homogeneity on surface, thereby influence printing quality, there is higher requirement to printing ink, if printing ink and metal coating material have good adhesion and spreading nature, can realize exempting from surface treatment, reduced technology and reduced the cost, product quality has also been promoted simultaneously. High-temperature disinfection is needed when the metal can is used for containing food and beverage, the printing ink has to meet the high-temperature water boiling performance, the pattern does not fall off or crack after water boiling, if a layer of gloss oil is spread on the printing ink, the glossiness cannot be influenced after water boiling, and the market demands the UV-LED curing ONEPASS printing ink free of bottom treatment.

Disclosure of Invention

In order to meet industrial purposes such as variable data printing of metal cans, the invention provides UV-LED curing ink-jet ink and a preparation method thereof, in particular to a UV-LED curing ONEPASS printing ink series, wherein the ink does not contain an organic solvent and has the characteristics of environmental protection; the ink can be instantly cured under the irradiation of a UV-LED light source; the continuity and the fluency are good, and the requirements of the ONEPASS printing mode are met; the hardness is moderate, and the scratch resistance is realized; can be printed on base materials such as metal, coated iron and the like without priming and treatment, has good adhesion, and is resistant to water boiling.

The object of the invention is achieved in the following way:

a UV-LED curing inkjet ink comprising the following components in percentage by weight:

3-15% of polyester acrylate prepolymer

3-15% of polyurethane acrylate prepolymer

60 to 80 percent of active monomer

1 to 5 percent of pigment

3 to 15 percent of photoinitiator

1 to 10 percent of auxiliary initiator

1 to 5 percent of phosphate

3 to 15 percent of dispersant

0.1 to 3 percent of auxiliary agent.

The viscosity of the polyester acrylate prepolymer is 150-1200 cps.

The molecular weight of the urethane acrylate prepolymer is 500-5000.

The active monomer comprises a monofunctional monomer, a difunctional monomer and a multifunctional monomer, wherein the weight content of the monofunctional monomer is 50-70% of the total weight of the active monomer, the weight content of the difunctional monomer is 10-40% of the total weight of the active monomer, and the weight content of the trifunctional or multifunctional monomer is 0-20% of the total weight of the active monomer.

The pigment is phthalocyanine pigment, quinacridone pigment, azo pigment, benzimidazolone pigment or carbon black pigment.

The phosphate ester is acrylic acid modified phosphate ester.

The photoinitiators include Norrish type I and Norrish type II photoinitiators.

The co-initiator is an active amine co-initiator.

The dispersant is at least one of modified acrylate block copolymer, olefine acid block copolymer, hyper-dispersant with anchor group and organic modified polysiloxane.

The auxiliary agent comprises at least one of a leveling agent, an anti-sticking agent, a thermal polymerization inhibitor and a deodorant.

The preparation method of the UV-LED curing ink-jet ink comprises the following specific steps: (1) dispersing and grinding a mixture of the pigment, the dispersing agent and 30% of active monomer by using grinding machine equipment to prepare color paste; (2) stirring and dissolving a photoinitiator, an auxiliary initiator, phosphate, an auxiliary agent, 70% of residual active monomer, a polyester acrylate prepolymer and a polyurethane acrylate prepolymer to prepare a pre-solution; (3) dispersing the pre-solution in color paste at high speed; (4) and finally, filtering the printing ink by using a microporous filter membrane.

Compared with the prior art, the UV ink-jet ink provided by the invention does not contain an organic solvent, and has the characteristics of environmental protection; the printing ink can be instantly cured under the irradiation of an LED lamp, the appearance is not sticky, and the requirement of quick printing is met; the ink has good fluency; the hardness is moderate, and the scratch resistance is realized; the adhesive force with the base material is good; the ink is boiling resistant, is used for variable data printing of metal cans, and has wide development prospect.

Detailed Description

The UV-LED curing ONEPASS printing ink series consists of polyester acrylate prepolymer, polyurethane acrylate prepolymer, photoinitiator and auxiliary initiator, phosphate, pigment, active monomer, dispersant and auxiliary agent, and the detailed description and preparation method of the components are as follows:

1. polyester acrylate prepolymers

The types of the prepolymers are more, different types of oligomers have different performances, and the performances of the oligomers with the same type and different structural units are different, so that the selection of the proper prepolymers has important significance for improving the performance of the ink, the requirements of a UV ink-jet ink system on the prepolymers include three important indexes of low viscosity, improvement of the film performance of the ink and maintenance of the stability of the system, and the polyester acrylate has good compatibility and affinity with the pigment, so that the system stability of the UV ink-jet ink and the continuity and smoothness of the ink-jet performance can be improved.

The functional group number of the polyester acrylate prepolymer applied to the UV ink-jet ink is generally 2-16, the viscosity is 150-1200cps (25 ℃), the consumption of the polyester acrylate is large, the viscosity of the ink is large, the consumption is small, the reactivity of the ink is low, the stability is poor, the hyperbranched polyester acrylate has higher activity and lower viscosity, the hyperbranched polyester acrylate is more preferably applied to the UV ink-jet ink, and in order to ensure that the low viscosity and the polyester acrylate with better activity, stability and high reactivity are ensured, the hyperbranched polyester acrylate with the viscosity of less than 600 centipoises at room temperature is preferably used.

Examples of commercial products which may be mentioned are polyester acrylates: CN 2302, CN 2301 and CN 2303 produced by Saedoma; 6361-100 and 6362-100 from Changxing chemical industries, Inc.

The polyester acrylate in the invention can account for 3-15% of the total weight of the UV ink-jet ink.

2. Urethane acrylate prepolymer

Because the macromolecular structure of the polyurethane acrylate prepolymer simultaneously contains structural units of urethane and acrylate, the excellent performances of polyurethane and acrylic resin are integrated, particularly aliphatic polyurethane acrylate has higher photocuring speed, good adhesive force, flexibility, wear resistance, low temperature resistance and outstanding high elasticity and elongation.

Generally, the higher the molecular weight of the oligomer, the higher the viscosity, and in order to meet the low viscosity requirement of the UV inkjet ink, the viscosity of the urethane acrylate should not be too high, and the molecular weight of the urethane acrylate prepolymer should not be too high, generally below 5000.

Commercially available urethane acrylates may be mentioned: CN series products of SARTOMER company (including CN929, CN964, CN945, CN965, CN968, CN98l, CN983, CN984, CN985, etc.); EBECRYL products from UCB Radcure corporation (including 294, 270, 657, 770, 830, 8301, 835, 8803, etc.); PHOTOMER series (including 6010, 6210, 6891, etc.) from Cognis; 6101, 6176, 6177, 6153, 6131 and the like of Changxing chemical.

The weight of the polyurethane acrylate accounts for 3-15% of the total weight of the UV ink-jet ink.

3. Pigment (I)

The pigment is selected from phthalocyanine pigment, quinacridone pigment, azo pigment, benzimidazolone pigment or carbon black pigment, and the spot color can be various organic pigments and inorganic pigments. The following are in terms of color index numbers: black pigments include cj pigment black 7 and 11; yellow pigments include cj pigment yellow 14, 17, 24, 34, 42, 74, 81, 83, 95, 98, 100, 104, 109, 110, 117, 120, 138, 151, 154, 180, etc.; the magenta pigment includes c.i. pigment red 1, 3, 17, 22, 23, 31, 38, 48: 2. 48: 3. 48: 4. 49: 1. 57: 1. 60: 1. 63: 1. 64: 1. 81, 83, 88, 92, 101, 104, 105, 108, 112, 114, 122, 123, 146, 149, 166, 168, 170, 177, 178, 179, 185, 190, 193, 202, 207, 255; cyan pigments include c.i. pigment blue 1, 2, 15: 1. 15: 2. 15: 3. 15: 4. 15: 5. 15: 6, etc.; spot color pigment violet 19, 23, 31, etc.

The spot color can be made by selecting pigments with different color numbers according to needs or by proportioning the pigments with different colors, but the manufacturing methods are the same.

4. Photoinitiators and co-initiators

The activation energy required to cause the monomer and oligomer to undergo curing polymerization is relatively high, high energy is required to carry out polymerization, and the activation energy required by using a photoinitiator is relatively low, and the photoinitiator absorbs light and is responsible for generating free radicals or cations to initiate polymerization of the monomer and oligomer.

There are two main types of photoinitiators, Norrish type I initiators, i.e. cleavage type free radical photoinitiators, which cleave after excitation to obtain an initiating free radical immediately, mostly aryl alkyl ketone derivatives, typically including benzoin derivatives, benzil ketal derivatives, dialkoxy acetophenones, α -hydroxyalkyl phenones, α -aminoalkylphenones, acylphosphine oxides, esteroxime ketone compounds, aryl peroxy ester compounds, halomethyl aryl ketones, organic sulfur compounds, benzoyl formate, etc., Norrish type II initiators, photoinitiators activated by actinic radiation and forming a free radical by extracting hydrogen from a second compound (becoming the actual initiating free radical), typically hydrogen abstraction type photoinitiators including benzophenone, thioxanthone, wherein this second compound is called a polymerization synergist or co-initiator, which is used in combination with Norrish type II initiators, including reactive tertiary amines, thiols, ketones, ethers, etc., and aryl ketones, which undergo a reduction reaction to generate reactive free radicals to promote a curing process with a certain degree of resistance to radiation, and which is the most common in the case of tertiary initiators.

Examples of Norrish type I initiators include DEAP, BDMM, BAPO, TPO, 184, 1173, 819, 2959, LTM, etc.; norrish type II initiators include DETX, EHA, EMK, etc.; examples of tertiary amine co-initiators are: EDAB, changxing chemicals 641, 6412 and 6420, etc. In the green environment-friendly coating, the photoinitiators 907, ITX and BP are forbidden, so the invention does not use the three photoinitiators.

The photoinitiation system comprises a Norrish I type Norrish II system and a tertiary amine co-initiation system. The initiator is preferably used in an amount of 3-15% by weight of the total ink, wherein the amount of the Norrish type I is 1-14%, the amount of the Norrish type II is 1-14%, and the amount of the tertiary amine co-initiator is 1-10%.

5. Reactive monomer

The active monomer is the main component of the UV ink-jet ink, the adding amount is in the range of 60-80%, meanwhile, the types of the active monomer are more, and different types of the active monomer have different performances and comprise a monofunctional active monomer, a difunctional active monomer and a polyfunctional active monomer.

Examples of monofunctional reactive monomers include styrene, methylstyrene, N-ethylene-2-pyrrolidone, butyl acrylate, octyl acrylate, isooctyl acrylate, 2-phenoxyethyllene, butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, hexyl acrylate, dihydroxy propyl acrylate, isobornyl acrylate, and tetrahydrofurfuryl acrylate.

Examples of difunctional reactive monomers include 1, 4-butanediol diacrylate, 1, 6-hexanediol diacrylate, polyethylene glycol diacrylate, propoxylated neopentyl glycol diacrylate, triethylene glycol divinyl ester, 1, 4-cyclohexanedimethanol divinyl ester, and the like.

Examples of the trifunctional and polyfunctional reactive monomers include trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate.

The invention adopts the following active monomer combination: 30-70% of a monofunctional reactive monomer; 10-30% of bifunctional reactive monomer; 0-20% of polyfunctional active monomer.

6. Phosphoric acid esters

The phosphate can increase the affinity with metal, in a UV system, the acrylate containing carbon-carbon double bonds is preferred, and the acrylic acid modified acrylate with different structures can improve the compatibility and stability of the system.

Acrylic modified phosphates which may be mentioned are: PAI1251 ever greater amount of chemical industry; PM-2 Japan chemical; PM-2 Shanghai Baochao chemical industry; HD-2 Jiangsu thick tripod chemical industry; b-02 and B-05 Guangzhou Boxing chemical industry; 1520. 1530, 1590, 3000, 3030, 3060 Guangzhou Jingde, etc.

1-5% of phosphate adhesion promoter.

7. Dispersing agent

In order to disperse and stably exist in a composition system of active monomers or oligomers and the like, the pigment particles need to be subjected to super-dispersing, the super-dispersing agent is a special surfactant, the molecular structure of the super-dispersing agent contains two groups opposite in solubility and polarity, one of the groups is a shorter polar group called a hydrophilic group, the molecular structure characteristics of the super-dispersing agent enable the super-dispersing agent to easily move to be arranged on the surface of a substance or a two-phase interface and reduce the interfacial tension, and the other group is a lipophilic group which is a macromolecule and is easy to move and can rapidly move to the surface of particles to play a role in wetting protection, multi-point anchoring is formed on the surface of the particles, an effective space stabilizing effect can be achieved, and a lipophilic film cannot be introduced into the surface of the particles, so that the service performance of a product cannot be influenced, the adsorption fastness of ink is improved.

Examples of hyperdispersant commercial products that may be mentioned are SollsPERSE 39000, SOLSPERSE32000, SOLSPERSE5000, Solsperse325000, Solsperse36000, SOLSPERSE22000, Disperbyk-111, 162, 163, 168 of AFCONA 3580 Bikk chemistry; EFKA additives 4310, 4330, 4030 of EFKA; dispers710, 685, 655, etc. of degussa.

The dispersant accounts for 3-10% of the total weight of the ink.

8. Auxiliary agent

Wetting and leveling agent

A wetting and leveling agent is also a surfactant in an inkjet ink to reduce the surface tension of the ink, reduce the contact angle on the substrate, and improve the wetting of the ink on the substrate. On the other hand, jettable inks must meet stringent performance standards so that they can be jetted with increased accuracy and reliability for extended periods of time. To achieve both wetting of the ink to the substrate and high jetting performance, the surface tension of the ink, which is the reciprocal drag force per unit length between two adjacent portions of the liquid surface, is reduced by the addition of one or more surfactants, which is an expression of molecular forces. When the molecules on the liquid surface are attracted by the molecules in the liquid to make the liquid surface tend to shrink, the direction of the molecules is tangential to the liquid surface. The liquid surface always has a tendency to shrink as much as possible due to the effect of surface tension, so that the droplets are spherical. The inkjet ink must have a certain surface tension. Surface tension has a significant effect on the formation of ink droplets and the quality of the ink droplets during the ink jetting process. The presence or absence of spills around the nozzle, the length of break-off of the droplet, the circumference of the droplet and its stability, the speed at which the droplet is formed and whether it is travelling in a straight line, etc. are all affected by the surface tension of the ink. Too high a surface tension makes the ink less prone to fine droplet formation and may present long break lengths or "tail" like droplets when broken, directly affecting the image quality. In addition, excessive surface tension makes the nozzle surface difficult to be wetted, and the ink aggregation around the nozzle can affect the linear running of fine droplets and also affect the wetting and penetration of the droplets to the printing material and the drying performance of the ink. It is generally required that the surface tension of the inkjet ink must be lower than the surface free energy of the substrate. If the surface tension is too low, the liquid drops are unstable, star-shaped sputtering points are easy to form, the non-image-text part is dirty, and the image quality is affected. The surface tension is controlled to be such that it spreads smoothly over the substrate material and forms sufficiently small droplets during the ink jet process. Suitable surface tensions for the UV ink are 22-28 dynes/cm.

Examples of surfactants include TEGO GLIDE450, TEGO GLIDE432, TEGO GLIDE500, TEGORAD2100, TEGORAD2300, TEGO WET 270, etc., available from TEGO; BYK-161, BYK-163, BYK-190, BYK-2100, BYK-333, etc., from Pico.

The addition amount is preferably 0.1-1.5% of the total weight of the ink.

The auxiliary agent may further contain a thermal polymerization inhibitor, a deodorant, a defoaming agent, a foam inhibitor or the like as appropriate.

The adding amount of the thermal polymerization inhibitor accounts for 0.05-1% of the total weight of the ink.

Odor removing agent: the adding amount accounts for 0.05-2% of the total weight of the ink.

The addition amount of the defoaming agent or the foam inhibitor accounts for 0.05 to 2 percent of the total weight of the ink.

9. The manufacturing method comprises the following steps:

the manufacture of the UV inkjet ink comprises the following steps: (1) dispersing and grinding a mixture of the pigment, the dispersing agent and 30% of active monomer by using grinding machine equipment to prepare color paste; (2) stirring and dissolving a photoinitiator, an auxiliary initiator, phosphate, an auxiliary agent, 70% of residual active monomer, a polyester acrylate prepolymer and a polyurethane acrylate prepolymer to prepare a pre-solution; (3) dispersing the pre-solution in color paste at high speed; (4) and finally, filtering the printing ink by using a microporous filter membrane.

The grinding and dispersing equipment is a colloid grinder, a high-speed disperser, a double-roller press, a bead mill, a three-roller mill and the like; dispersion can also be carried out using ultrasonic energy, and many different types of materials can be used as milling media, such as glass, ceramic, metal, plastic, and the like.

Example (b):

1. the detection method comprises the following steps:

(1) particle size: the ink or color paste is diluted by 500-2000 times by using a solvent according to the pigment concentration, and the average particle size range D50 is measured by using a laser particle sizer.

(2) Viscosity: an NDJ-5S rotational viscometer of Shanghai Nirun Intelligent science and technology Limited is adopted;

(3) surface tension: the BZY-1 surface tension meter produced by Shanghai Hengping instrument and meter factories is adopted for testing;

(4) speed of curing

Power with UV-LED lamp: electric power 610W; irradiating 8W/cm²The distance between the lamps is about 6mm, and the energy of the lamp which goes on the conveyor belt once is as follows: 300-600mj/cm². The determination that curing has occurred is made by rubbing with a finger on the printed surface thereby observing that the ink is not smeared or smeared on the surface.

(5) Pencil hardness test reference standard: GB/T9286-1998

Scraping the ink layer into a thin layer with a thickness of 12 μm by using a glass substrate, and irradiating by using a UV-LED curing machine at a speed of 8W/cm²And 5S is solidified to ensure complete solidification, and a pencil hardness meter is adopted for hardness detection.

(6) Adhesion force

Scraping the ink layer into a thin layer with a thickness of 12 μm on an aluminum plate or a coated iron substrate, and irradiating by a UV-LED curing machine to obtain a layer with a thickness of 8W/cm²Curing for 5S, ensureAnd (3) completely curing, and testing the adhesion performance detection reference standard by a grid cutting method: GB/T6739-2006:

level 0: the edge of the scribing line is smooth, and no mark falls off at the edge and the intersection point of the scribing line.

Level 1: there was a small mark drop at the scribe line intersection and the total area dropped was less than 5%.

And 3, level: there was a small mark drop at the scribe line intersection and the total area dropped was less than 35%.

And 5, stage: the sheet-forming marks are separated at the cross points of the scribing lines, and the total separation area is more than 65 percent.

(7) Continuity and fluency

And continuously inspecting the continuous printing capability of the ink under a certain specific temperature-voltage, wherein the temperature of a set spray head on the ink to be tested is 36-45 ℃ and the voltage is 12-15V during detection, 5 plates are continuously printed under each condition, the spray head is printed for testing after the continuity of one plate is printed, the test is compared with a standard sample, and if the number of broken lines is less than 1% of the total number of spray holes of the spray head, the continuity of the ink at the temperature-voltage is qualified.

And (3) smoothness inspection of the adaptability of the ink to the spray nozzle (no damage to the spray nozzle), wherein the ink to be detected is loaded on a machine during detection, the spray nozzle test strips are printed every day, the quantity of the defects of the spray nozzle test strips, such as broken lines and broken line lines, is compared with a standard sample, and the smoothness of the ink in the time interval is qualified when the quantity of the defects of the spray nozzle test strips, such as broken line and broken line is less than 1%.

(8) Water boiling test: scraping the ink layer into a thin layer with a thickness of 12 μm on an aluminum plate or a coated iron substrate, and irradiating by a UV-LED curing machine to obtain a layer with a thickness of 8W/cm²Curing for 5S to ensure complete curing, scraping the ink layer into a part with the thickness of 4 mu mUV gloss oil, and irradiating by a UV-LED curing machine to 8W/cm²And curing for 5S to ensure complete curing, and cooking in a pressure cooker at 121 ℃ for 30min, wherein the part which is not added with the gloss oil does not fall off and wrinkle, and the part which is added with the gloss oil does not lose gloss, does not fall off and wrinkle, and is qualified.

2. Detailed description of the preferred embodiments

The following are preparation examples of the present invention, and it should be understood that the present invention is not limited to the following examples, but is only for illustrating the scope of the present invention. In addition, various changes or modifications of the invention, which are equivalent to those skilled in the art, are also included in the scope of the invention as claimed, and the proportion in the examples is by weight.

Examples 1-4 yellow ink formulations are shown in table 1:

the manufacturing method comprises the following steps: 1. the mixture of the pigment, the dispersant and 30 percent of active monomer is dispersed and ground by a grinder device to prepare color paste, a ZETA experimental grinder of German Chiz-resistant company (CNETZSCH) is used for grinding and dispersing, and the dispersing and grinding time is 2 to 4 hours.

2. Stirring and dissolving a photoinitiator, an auxiliary initiator, phosphate, an auxiliary agent, 70% of residual active monomer, a polyester acrylate prepolymer and a polyurethane acrylate prepolymer to prepare a pre-solution. The stirring and dissolving process uses an experimental emulsifying machine of Shanghai Weiyu electromechanical manufacturing company Limited, and stirring and dissolving are carried out at the rotating speed of 1000 revolutions per minute for 2-4 hours.

3. And dispersing the pre-solution in the color paste at a high speed. The high-speed dispersion process uses an experimental emulsifying machine of Shanghai Weiyu electromechanical manufacturing company, which is carried out at the rotating speed of 5000-.

4. And finally, filtering the printing ink by using a microporous filter membrane, wherein the filtering precision is 1-3 mu m.

Examples 5-8 magenta ink formulations are shown in Table 2:

the manufacturing method comprises the following steps: the same procedure as in examples 1 to 4 was employed.

Examples 9-12 cyan ink formulas Table 3:

The black ink formulations of examples 13-16 are shown in Table 4:

The spot color violet formulations of examples 17 and 21-22, and the spot color green formulations of examples 18-20 are shown in Table 5:

3. The results of the performance measurements are shown in Table 6.

4. And (4) conclusion:

as seen from the above data: the UV ink-jet ink disclosed by the invention does not contain an organic solvent, and has the characteristics of environmental friendliness; the printing ink can be instantly cured under the irradiation of an LED lamp, the appearance is not sticky, and the requirement of quick printing is met; the ink has good fluency; the hardness is moderate, and the scratch resistance is realized; the adhesive force with the base material is good; the ink is boiling resistant, is used for variable data printing of metal cans, and has wide development prospect.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the overall concept of the present invention, and these should also be considered as the protection scope of the present invention.

Claims

1. A UV-LED curable inkjet ink, characterized by: the ink-jet ink comprises the following components in percentage by weight:

3-15% of polyester acrylate prepolymer

3-15% of polyurethane acrylate prepolymer

60 to 80 percent of active monomer

1 to 5 percent of pigment

3 to 15 percent of photoinitiator

1 to 10 percent of auxiliary initiator

1 to 5 percent of phosphate

3 to 15 percent of dispersant

0.1 to 3 percent of auxiliary agent.

2. The UV-LED curable inkjet ink according to claim 1, wherein: the viscosity of the polyester acrylate prepolymer is 150-1200 cps.

3. The UV-LED curable inkjet ink according to claim 1, wherein: the molecular weight of the urethane acrylate prepolymer is 500-5000.

4. The UV-LED curable inkjet ink according to claim 1, wherein: the active monomer comprises a monofunctional monomer, a difunctional monomer and a multifunctional monomer, wherein the weight content of the monofunctional monomer is 50-70% of the total weight of the active monomer, the weight content of the difunctional monomer is 10-40% of the total weight of the active monomer, and the weight content of the trifunctional or multifunctional monomer is 0-20% of the total weight of the active monomer.

5. The UV-LED curable inkjet ink according to claim 1, wherein: the pigment is phthalocyanine pigment, quinacridone pigment, azo pigment, benzimidazolone pigment or carbon black pigment.

6. The UV-LED curable inkjet ink according to claim 1, wherein: the phosphate ester is acrylic acid modified phosphate ester.

7. The UV-LED curable inkjet ink according to claim 1, wherein: the photoinitiators include Norrish type I and Norrish type II photoinitiators.

8. The UV-LED curable inkjet ink according to claim 1, wherein: the co-initiator is an active amine co-initiator.

9. The UV-LED curable inkjet ink according to claim 1, wherein: the dispersant is at least one of modified acrylate block copolymer, olefine acid block copolymer, hyper-dispersant with anchor group and organic modified polysiloxane.

10. The UV-LED curable inkjet ink according to claim 1, wherein: the auxiliary agent comprises at least one of a leveling agent, an anti-sticking agent, a thermal polymerization inhibitor and a deodorant.

11. The method of making a UV-LED curable inkjet ink according to any one of claims 1 to 10, wherein: the method comprises the following specific steps: (1) dispersing and grinding a mixture of the pigment, the dispersing agent and 30% of active monomer by using grinding machine equipment to prepare color paste; (2) stirring and dissolving a photoinitiator, an auxiliary initiator, phosphate, an auxiliary agent, 70% of residual active monomer, a polyester acrylate prepolymer and a polyurethane acrylate prepolymer to prepare a pre-solution; (3) dispersing the pre-solution in color paste at high speed; (4) and finally, filtering the printing ink by using a microporous filter membrane.