A type of LED-curable, non-yellowing, hot stamping, offset printing ink fountain matte ink

Abstract

This invention relates to the field of curing printing coatings, specifically disclosing an LED-cured, non-yellowing, hot stamping offset ink fountain matte coating, comprising the following components in parts by weight: 35-55 parts of UV-modified polyester acrylic resin; 20-30 parts of UV monomer; 1-5 parts of additives; 6-10 parts of photoinitiator; 1-5 parts of photoinitiator auxiliary photoinitiator; and 10-25 parts of filler. This invention uses an LED lamp as the curing light source. LEDs are cold light sources, generating almost no heat during curing, thus preventing thermal expansion or moisture loss of the white cardboard paper, maintaining the paper's original flexibility. After die-cutting, the cut is smooth and even, without edge bursting or powdering, significantly reducing the scrap rate. Simultaneously, the formula of this invention provides a suitable surface finish for the coating, allowing for firm adhesion of the hot stamping foil, resulting in complete, non-flaking, and bubble-free hot stamping patterns, meeting the requirements of high-end packaging for hot stamping decoration.

Description

Technical Field

[0001] This invention belongs to the field of curing printing coating technology, specifically relating to an LED-curable, non-yellowing, hot stamping offset printing ink fountain matte oil. Background Technology

[0002] In the printing and packaging industry, offset ink fountain matte ink is widely used for surface coating of white cardboard to achieve a matte effect and protect the printed pattern. Traditional ink fountain matte ink is mostly cured using UV mercury lamps (ultraviolet high-pressure mercury lamps). However, the surface temperature of a UV mercury lamp can reach over 800°C during operation. Although the ambient temperature can be reduced through air or water cooling systems, a large amount of heat still accumulates in the curing area, causing the paper to expand and lose moisture rapidly. When the paper undergoes the die-cutting process, the heated paper becomes more brittle, making it prone to edge bursting and powdering at the die-cut edges. This is especially problematic for high-quality products such as pharmaceutical and cosmetic packaging, where edge bursting leads to a high scrap rate.

[0003] In recent years, LED curing technology has gradually attracted attention due to its cold light source characteristics (the surface temperature of LED lamps is typically below 50°C, and they produce almost no infrared radiation). Using LED curing can prevent thermal damage to paper at the source, fundamentally solving the problem of edge bursting during die-cutting.

[0004] However, existing commercially available LED-cured offset ink fountain matte inks still have many drawbacks: First, the wavelength of LED light sources is relatively narrow (usually 365nm, 385nm, or 395nm), which is different from the broad-spectrum wavelength of UV mercury lamps, resulting in poor curing of traditional photoinitiation systems under LEDs, leading to sticky paint film surfaces and insufficient hardness; second, existing LED matte paint films are prone to yellowing during long-term use or high-temperature storage, affecting the appearance of packaging; third, many LED matte inks have too low surface energy, making it difficult to perform hot stamping processes (hot stamping foil cannot adhere firmly), limiting their application in high-end packaging.

[0005] Therefore, developing an offset ink fountain matte ink that can achieve LED cold light source curing, ensure complete curing of the paint film without yellowing, and has excellent hot stamping performance has significant market value and application prospects. Summary of the Invention

[0006] The purpose of this invention is to provide an LED-curable, non-yellowing, hot stamping offset ink fountain matte ink to solve the technical problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A matte ink for LED curing, non-yellowing, and hot stamping, comprising the following components in parts by weight:

[0009] 35-55 parts of UV-modified polyester acrylic resin;

[0010] 20-30 parts of UV monomer;

[0011] 1-5 parts of auxiliary agent;

[0012] 6-10 parts of photoinitiator;

[0013] 1-5 parts of photoinitiator;

[0014] 10-25 parts of filler.

[0015] Preferably, the additives include leveling agents or defoamers, wherein the leveling agent is selected from one or more of polyether-modified polydimethylsiloxane and acrylate leveling agents; the defoamer is selected from polysiloxane defoamers; the photoinitiator is selected from one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819), 1-hydroxycyclohexylphenyl ketone (184), and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369); the auxiliary photoinitiator is selected from one or more of ethyl-4-dimethylaminobenzoate (EDB), ethyl 4-dimethylaminobenzoate (EOA), and acrylated amine; and the filler is selected from one or more of fumed silica, precipitated silica, talc, and calcium carbonate.

[0016] The preparation method of LED-curable, non-yellowing, hot stamping, offset printing ink fountain matte ink includes the following steps:

[0017] S1. Premixing: Mix UV-modified polyester acrylic resin with 30%~50% of UV monomer in the formulation, and stir at 50~60℃ for 15~30 minutes to obtain a premixed resin solution; S2. Photoinitiator system dissolution: Add photoinitiator and photoinitiator to the premixed resin solution, heat to 65~75℃, and stir for 20~40 minutes until completely dissolved to obtain a photoinitiating resin solution; S3. Filler dispersion: Premix the filler with the remaining UV monomer to prepare a filler slurry, then add it to the photoinitiating resin solution, add additives, and disperse at room temperature at 800~1200rpm for 30~60 minutes to obtain a coarse dispersion slurry; S4. Grinding: Grind the coarse dispersion slurry 2~4 times with a three-roll mill until the fineness is ≤15μm to obtain a ground slurry; S5. Vacuum degassing: Degas the ground slurry under a vacuum of -0.08~-0.1MPa for 15~30 minutes; S6. Filtration and Packaging: The degassed slurry is filtered and then packaged.

[0018] Preferably, the stirring speed in S1 is 200~400 rpm.

[0019] Preferably, the stirring speed in S2 is 400~600 rpm.

[0020] Preferably, the filtration in S6 uses a 200-400 mesh filter.

[0021] The ink fountain matte ink is used for offset printing on white cardboard, cured with LED lights, and is used for pharmaceutical packaging, toy packaging, cosmetic packaging, shoe box packaging, or food packaging.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] This invention uses LED lights as the curing light source. LEDs are cold light sources, generating almost no heat during the curing process. This prevents thermal expansion or moisture loss of the white cardboard paper, allowing the paper to maintain its original flexibility. After die-cutting, the cut is smooth and even, without edge bursting or powdering, significantly reducing the scrap rate.

[0024] By rationally combining UV-modified polyester acrylic resin, UV monomers, photoinitiators and photoinitiators, the system can still achieve efficient cross-linking and curing under narrow-wavelength LED light sources, resulting in a coating film with high hardness, scratch resistance, thorough surface drying, and no residual stickiness.

[0025] The photoinitiator system selected in this invention decomposes completely after LED curing, leaving minimal residue. Furthermore, the resin itself possesses high weather resistance, preventing yellowing of the coating film after prolonged storage or heating, thus maintaining the high-definition transparency of the matte coating. This makes it particularly suitable for packaging printing on white or light-colored substrates. Simultaneously, the formulation of this invention ensures a suitable surface finish for the coating film, allowing for firm adhesion of the hot stamping foil. This results in complete, peel-free, and bubble-free hot stamping patterns, meeting the requirements of high-end packaging for hot stamping decoration.

[0026] The preparation method provided by this invention employs stepwise feeding, temperature control, filler pre-dispersion, and vacuum degassing to ensure uniform dispersion of each component and stability of the system. Three-roll milling combined with vacuum degassing results in ink fountain matte ink with a fineness ≤15μm, good leveling properties, and excellent printability. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1:

[0029] An LED-curable, non-yellowing, hot stamping offset inkjet inkjet is composed of the following components in parts by weight: 42 parts of UV-modified polyester acrylic resin (Changxing Chemical 6315); 24 parts of UV monomer tripropylene glycol diacrylate (TPGDA); additives including leveling agent and defoamer, wherein the leveling agent is BYK-333 (polyether-modified polydimethylsiloxane) 1.5 parts, and the defoamer is BYK-066 (polysiloxane) 0.5 parts; the photoinitiator is TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide) 7 parts; the auxiliary photoinitiator is EDB (ethyl-4-dimethylaminobenzoate) 3 parts; and the filler is fumed silica (Evonik OK-412, average particle size 5μm) 18 parts.

[0030] Preparation method:

[0031] First, a premixing step is performed: 42 parts of Changxing 6315 and 7.2 parts (accounting for 30% of the total UV monomer) of TPGDA are added to a reactor equipped with heating and stirring functions, the temperature is raised to 55°C, and the mixture is stirred at 300 rpm for 20 minutes to obtain a uniform premixed resin solution.

[0032] Then, the photoinitiator system was dissolved: 7 parts TPO and 3 parts EDB were added to the premixed resin solution, the temperature was raised to 70°C, the stirring speed was adjusted to 500 rpm, and the stirring was kept at a constant temperature for 30 minutes until the photoinitiator was completely dissolved (no particles were visible), and the photoinitiator resin solution was obtained.

[0033] Next, the filler was dispersed: 18 parts of OK-412 and the remaining 16.8 parts of TPGDA were pre-mixed in a high-speed disperser and pre-dispersed at 600 rpm for 10 minutes to prepare a filler slurry. Then, the filler slurry was slowly added to the photoinitiator resin solution, along with 1.5 parts of BYK-333 and 0.5 parts of BYK-066, and dispersed at 1000 rpm for 45 minutes at room temperature to obtain a coarse dispersion slurry.

[0034] Next, grinding is performed: the coarsely dispersed slurry is ground using a three-roll mill. The fineness after the first grinding is ≤30μm, the fineness after the second grinding is ≤18μm, the fineness after the third grinding is ≤10μm, and the final fineness is 10μm, which is qualified (≤15μm).

[0035] Next, perform vacuum degassing: transfer the ground slurry to a vacuum degassing tank, set the vacuum level to -0.09 MPa, and degas for 20 minutes until no bubbles overflow from the surface.

[0036] Final filtration and packaging: After being filtered under pressure through a 300-mesh stainless steel filter, it is placed in a sealed plastic bucket and stored away from light.

[0037] Performance test results:

[0038] The ink fountain matte oil prepared in this embodiment is a pale yellow, semi-transparent paste, uniform and free of particles, with a fineness of 10μm. After curing using a 395nm LED lamp with an energy of 200 mJ / cm², the surface is dry and non-sticky to the touch. Colorimeter testing showed that after curing and baking at 80℃ for 24 hours, the yellowing ΔE value was ≤0.8, with no visible yellowing. The 60° gloss was 8.5 GU, exhibiting a matte effect. Hot stamping adhesion testing, using hot-pressed hot stamping foil and then peeling it off with 3M tape, showed the hot stamping pattern remained intact without peeling, achieving a 5B grade. Die-cutting 100 samples onto white cardboard resulted in a 0% edge bursting rate. Compared to a UV mercury lamp with the same capacity, LED curing saves 58% energy.

[0039] Example 2

[0040] In this embodiment, the LED-curable, non-yellowing, hot stamping offset ink fountain matte ink is composed of the following components in parts by weight: 48 parts of UV-modified polyester acrylic resin (Changxing Chemical 6320, high flexibility); 22 parts of UV monomer, tripropylene glycol diacrylate (DPGDA); additives including leveling agent and defoamer, wherein the leveling agent is Tego Glide 450 (2.0 parts) and the defoamer is Tego Foamex 810 (1.0 part); 6 parts of photoinitiator 819 (phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide); 4 parts of auxiliary photoinitiator EOA (ethyl 4-dimethylaminobenzoate); and 12 parts of filler, fumed silica (Evonik OK-520, average particle size 4μm).

[0041] Preparation method:

[0042] First, premixing is performed: 48 parts of Changxing 6320 and 8.8 parts (accounting for 40% of the total UV monomer) of DPGDA are added to the reactor, the temperature is raised to 60℃, and the mixture is stirred at 400 rpm for 15 minutes.

[0043] Then, photo-initiated dissolution was performed: 6 parts of 819 and 4 parts of EOA were added, the temperature was raised to 75°C, and the mixture was stirred at 600 rpm for 25 minutes until completely dissolved.

[0044] Next, the filler was dispersed: 12 parts of OK-520 and the remaining 13.2 parts of DPGDA were premixed into a slurry, which was then added to the main reactor along with 2.0 parts of Tego Glide 450 and 1.0 parts of Tego Foamex 810. The mixture was dispersed at 900 rpm for 60 minutes at room temperature.

[0045] Then grind: Grind twice with a three-roll mill. The fineness of the first pass is ≤25μm and the fineness of the second pass is ≤8μm.

[0046] Then vacuum degassing: vacuum degree -0.08 MPa, degassing for 30 minutes.

[0047] Final filtration and packaging: Packaged after filtration through a 400-mesh filter.

[0048] Performance test results:

[0049] The matte ink produced in this embodiment has a fineness of 8 μm. It can be fully cured using a 385nm LED lamp with an energy of 180 mJ / cm². Flexibility testing showed that the film did not crack after being folded 180° 10 times. The yellowing ΔE (80℃, 24h) was 0.6. The 60° gloss was 6.2 GU. Hot stamping adhesion reached grade 5B. 500 samples were die-cut from white cardboard pharmaceutical packaging, and the edge bursting rate was 0%.

[0050] Example 3:

[0051] In this embodiment, the LED-curable, non-yellowing, hot stamping offset ink fountain matte varnish is composed of the following components in parts by weight: 36 parts of UV-modified polyester acrylic resin (Changxing Chemical 6310); 28 parts of UV monomer, ethoxylated trimethylolpropane triacrylate (TMPTA); additives including leveling agent and defoamer, wherein the leveling agent is BYK-358N (acrylate) 0.6 parts and the defoamer is BYK-066 0.4 parts; the photoinitiator is a compound of TPO and 184, wherein TPO is 5 parts and 184 is 5 parts, totaling 10 parts; the photoinitiator is EDB 1.5 parts; and the filler is a mixture of 18 parts of fumed silica (Evonik OK-412) and 7 parts of 1250 mesh talc powder, totaling 25 parts.

[0052] Preparation method:

[0053] First, premixing was performed: 36 parts of Changxing 6310 and 11.2 parts (40% of the total UV monomers) of TMPTA were added to the reactor, heated to 50°C, and stirred at 200 rpm for 30 minutes. Then, photoinitiated dissolution was performed: 5 parts of TPO, 5 parts of 184, and 1.5 parts of EDB were added, heated to 65°C, and stirred at 400 rpm for 40 minutes until completely dissolved.

[0054] Next, the filler was dispersed: 18 parts OK-412, 7 parts talc, and the remaining 16.8 parts TMPTA were premixed into a thick slurry, which was then added to the main reactor along with 0.6 parts BYK-358N and 0.4 parts BYK-066. The mixture was dispersed at 1200 rpm for 30 minutes at room temperature. Afterward, grinding was performed: the mixture was ground four times using a three-roll mill until the final fineness was ≤10μm. Then, vacuum degassing was carried out: the vacuum degree was -0.10 MPa, and degassing was performed for 15 minutes. Finally, the mixture was filtered and packaged.

[0055] Performance test results: The matte ink prepared in this embodiment has a fineness of 10μm, a delicate and smooth feel, and no graininess. The 60° gloss is 4.5 GU, exhibiting a high matte effect. Cured using a 385nm LED lamp with an energy of 250 mJ / cm², the hot stamping adhesion reaches grade 4B (suitable for commonly used hot stamping films in cosmetics). The yellowing ΔE value is 0.9. 300 samples were die-cut on white cardstock, and the edge bursting rate was 0%.

[0056] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0057] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A matte ink for LED curing, non-yellowing, hot stamping, and offset printing, characterized in that: The components include the following parts by weight: 35-55 parts of UV-modified polyester acrylic resin; 20-30 parts of UV monomer; 1-5 parts of auxiliary agent; 6-10 parts of photoinitiator; 1-5 parts of photoinitiator; 10-25 parts of filler.

2. The LED-curable, non-yellowing, hot stamping, offset printing ink fountain matte ink according to claim 1, characterized in that, The additives include leveling agents or defoamers. The leveling agent is selected from one or more of polyether-modified polydimethylsiloxane and acrylate leveling agents. The defoamer is selected from polysiloxane defoamers. The photoinitiator is selected from one or more of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819), 1-hydroxycyclohexylphenyl ketone (184), and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369). The auxiliary photoinitiator is selected from one or more of ethyl-4-dimethylaminobenzoate (EDB), ethyl 4-dimethylaminobenzoate (EOA), and acrylated amine. The filler is selected from one or more of fumed silica, precipitated silica, talc, and calcium carbonate.

3. The method for preparing the LED-curable, non-yellowing, hot stamping offset printing matte ink according to any one of claims 1-2, characterized in that, Includes the following steps: S1. Premixing: Mix UV-modified polyester acrylic resin with 30%~50% of UV monomer in the formulation, and stir at 50~60℃ for 15~30 minutes to obtain a premixed resin solution. S2. Photoinitiator system dissolution: Add photoinitiator and photoinitiator to the premixed resin solution, heat to 65~75℃, stir for 20~40 minutes until completely dissolved, and obtain photoinitiator resin solution; S3. Filler dispersion: Premix filler with the remaining UV monomer to prepare filler slurry, then add it to the photoinitiator resin solution, add additives, and disperse at room temperature at 800~1200 rpm for 30~60 minutes to obtain coarse dispersion slurry; S4. Grinding: Grind the coarsely dispersed slurry 2-4 times with a three-roll mill until the fineness is ≤15μm to obtain the ground slurry; S5. Vacuum degassing: Degas the ground slurry under a vacuum of -0.08~-0.1MPa for 15-30 minutes; S6. Filtration and packaging: Filter and package the degassed slurry.

4. The preparation method according to claim 3, characterized in that, The stirring speed mentioned in S1 is 200~400 rpm.

5. The preparation method according to claim 3, characterized in that, The stirring speed mentioned in S2 is 400~600 rpm.

6. The preparation method according to claim 3, characterized in that, The filtration described in S6 uses a 200-400 mesh filter.

7. The application of the LED-cured, non-yellowing, hot stamping, offset printing ink fountain matte ink according to claim 1, characterized in that, The ink fountain matte ink is used for offset printing on white cardboard, and cured with LED lights.

8. The application according to claim 7, characterized in that, The printing is used for pharmaceutical packaging, toy packaging, cosmetic packaging, shoe box packaging, or food packaging.