High-shading UV-curable black ink containing nano titanium dioxide

Abstract

The invention discloses a high-shading UV-curable black ink containing nano titanium dioxide, which comprises the following components in percentage by weight: 15-30% of ultraviolet light fixing resin, 15-25% of reactive diluent, 8-15% of carbon black, 10-20% of nano titanium dioxide, 2-6% of photoinitiator system and 1-3% of assistant, the original particle size of the nano titanium dioxide is 10-20 nm, the original particle size of the reactive diluent is 10-20 nm, the original particle size of the carbon black is 10-20 nm, and the original particle size of the photoinitiator system is 10-20 nm. And the surface of the composite material is treated by an organosilane or titanate coupling agent. The nano titanium dioxide subjected to special surface treatment is introduced, so that a plurality of key technical problems of carbon black dispersity, thick film UV curing activity, glass / PC base material adhesion and the like are solved, and the nano titanium dioxide is suitable for the fields of AR / VR glasses frames, precise optical devices and the like with strict requirements on shading property, adhesion and thick film curing property.

Description

Technical Field

[0001] This invention relates to the field of radiation curing materials technology, specifically to a high-opacity, UV-curable black ink containing nano-titanium dioxide. Background Technology

[0002] UV-curable inks are widely used in the printing, coating, and electronics industries due to their advantages such as fast curing speed, low energy consumption, and no volatile organic compound (VOC) emissions. Among them, black inks are particularly in demand due to their excellent hiding and decorative effects. Especially in AR / VR and precision optical equipment, high-shielding black inks are required to absorb stray light. To achieve high shielding, a large amount of carbon black must be added, but this leads to:

[0003] 1. Poor dispersibility: Carbon black is prone to agglomeration, which leads to unstable ink storage, uneven coating, and affects the light-blocking effect and appearance.

[0004] 2. Curing obstacles: High carbon black content severely absorbs and scatters UV light, resulting in low efficiency of photoinitiators and failure to cure the ink deep within the film. This is especially noticeable when the film thickness exceeds 30μm, leading to incomplete curing, reduced adhesion, and a sticky surface.

[0005] 3. Adhesion challenge: Incompletely cured resin systems are difficult to bond firmly to hard-to-adhere substrates such as glass and PC.

[0006] Existing technologies typically address these issues partially by optimizing the photoinitiator system or adding adhesion promoters, but the effects are limited, especially when pursuing thick films of 20μm or more, or even up to 100μm, it is difficult to balance light-blocking properties, uniformity, and complete curing. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-opacity, UV-curable black ink containing nano-titanium dioxide. This ink solves several key technical problems such as carbon black dispersibility, thick film UV curing activity, and adhesion to glass / PC substrates by introducing a specially surface-treated nano-titanium dioxide.

[0008] The technical solution of the present invention is as follows:

[0009] A high-opacity, UV-curable black ink containing nano-titanium dioxide comprises the following components by weight percentage: 15-30% UV-fixing resin, 15-25% reactive diluent, 8-15% carbon black, 10-20% nano-titanium dioxide, 2-6% photoinitiator system, and 1-3% additives, wherein the original particle size of the nano-titanium dioxide is 10-20 nm, and its surface is treated with an organosilane or titanate coupling agent.

[0010] Furthermore, the UV-fixing resin is an oligomer containing unsaturated double bonds, and may be one or a mixture of epoxy acrylate (EA), polyurethane acrylate (PUA), polyester acrylate (PEA), pure acrylic esterified resin, and adhesion-promoting functional resin.

[0011] Furthermore, the reactive diluent can be a monofunctional, difunctional, or multifunctional diluent. The monofunctional diluents include isobornyl acrylate (IBOA), lauryl acrylate (LA), methoxy polyethylene glycol acrylate (MPEGA), hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), caprolactone acrylate (ICLA), tetrahydrofuran acrylate (THFA), and phenol EO-modified acrylate (PEA). The difunctional diluents include tripropylene glycol diacrylate (TPGDA), neopentyl glycol diacrylate (NPGDA), and hexylene glycol diacrylate. The diluents include diol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), polyethylene glycol (200) diacrylate (PEG(200)DA), propoxylated neopentyl glycol diacrylate (NPG(PO)2DA), and the multifunctional diluents include trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), propoxylated glycerol triacrylate (GPTA), ethoxylated trimethylolpropane triacrylate (TMP(EO)3TA), and tri(2-hydroxyethyl)isocyanurate triacrylate.

[0012] Furthermore, the photoinitiator system can employ a cleavage-type (Type I) photoinitiator or an acylphosphide-based photoinitiator. The cleavage-type (Type I) photoinitiator includes 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173 / HMPP), 1-hydroxycyclohexylphenyl ketone (184 / HCPK), 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (907), and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (3...). 69), 2,2-dimethoxy-1,2-diphenylethane-1-one (BDK / 651), wherein the acyl phosphorus oxide photoinitiator includes (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819 / BAPO), bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO), and ethyl-2,4,6-trimethylbenzoylphenylphosphonate (TPO-L).

[0013] Furthermore, the additives include dispersants, leveling agents, light stabilizers, defoamers, matting agents, and adhesion promoters.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] 1. Excellent processability and film quality: The introduction of nano-titanium dioxide enables the high-content carbon black to be dispersed stably and uniformly, resulting in inks with good flowability, storage stability, and smooth coating surface.

[0016] 2. Breakthrough thick film curing capability: Successfully solved the problem of thick film curing of high light-blocking inks, and can achieve complete curing of 50-100μm or even thicker film layers, greatly expanding its application range in high-end optical products.

[0017] 3. Exceptional adhesion performance: Through the surface chemical action of nano-titanium dioxide, the ink is provided with universal and strong adhesion, especially suitable for glass and PC substrates commonly used in AR / VR devices.

[0018] 4. Synergistic effect: This invention achieves a synergistic effect of "1+1+1>3" through the unique combination of "surface-treated nano-titanium dioxide + high-structure carbon black + photoinitiator", and the overall performance far exceeds the expectations of simply adding up the components. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] To illustrate the technical solution described in this invention, specific embodiments are described below.

[0021] Example

[0022] This invention provides a high-opacity, UV-curable black ink containing nano-titanium dioxide, comprising the following components by weight percentage: 15-30% UV-fixing resin, 15-25% reactive diluent, 8-15% carbon black, 10-20% nano-titanium dioxide, 2-6% photoinitiator system, and 1-3% additives. The nano-titanium dioxide has an original particle size of 10-20 nm, and its surface is treated with an organosilane or titanate coupling agent to ensure good compatibility and dispersibility in the ink system.

[0023] The ultraviolet-fixing resin is an oligomer containing unsaturated double bonds, which forms the main body of the cured film network structure and is responsible for providing basic physicochemical properties. One or more of the following resins can be used in combination:

[0024] Epoxy acrylate (EA):

[0025] Features: Fast curing speed, high hardness, and good chemical resistance.

[0026] Examples of available commercial models:

[0027] Changxing Chemical: DR-E series (e.g., DR-E 610, DR-E 712), CNUVE 151. Sartoma: CN104, CN120, CN111. Nippon Synthetic Chemicals: REP-210, REP-1680.

[0028] Polyurethane acrylate (PUA):

[0029] Features: Excellent flexibility, abrasion resistance, high elasticity and impact resistance.

[0030] Examples of available commercial models:

[0031] Changxing Chemical: DR-U series (e.g., DR-U 505, DR-U 606), UX-6000 series. Sartoma: CN965, CN991, CN968 (high elongation), CN929 (aliphatic). Mitsubishi (Japan): UA-160TM, UA-306H, UA-306T.

[0032] Polyester acrylate (PEA):

[0033] Features: Light color, good leveling properties, and good flexibility.

[0034] Examples of available commercial models: Sartoma: CN293, CN2250, CN2253. Changxing Chemical: DR-J 103, DR-J 104.

[0035] Pure acrylic esterified resin:

[0036] Features: Excellent resistance to yellowing and good flexibility.

[0037] Examples of available commercial models: Sartoma: CN9001, CN9002, CN9013.

[0038] Adhesion-promoting functional resins:

[0039] Characteristics: The molecule contains strongly polar groups.

[0040] Examples of available commercial models:

[0041] Phosphate-containing acrylates: Sartoma CD9051, CN704; Acid-containing acrylates: Sartoma CN7040H, CN775; Silicon-containing alkyl acrylates: Sartoma CN9800 series.

[0042] The reactive diluent may be a monofunctional diluent, a difunctional diluent, or a multifunctional diluent.

[0043] Monofunctional diluents:

[0044] Available types and models:

[0045] Isoborneol acrylate (IBOA), lauryl acrylate (LA), methoxy polyethylene glycol acrylate (MPEGA), hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), caprolactone acrylate (ICLA), tetrahydrofuran acrylate (THFA), and phenol EO modified acrylate (PEA).

[0046] Bifunctional diluent:

[0047] Available types and models:

[0048] Tripropylene glycol diacrylate (TPGDA), neopentyl glycol diacrylate (NPGDA), hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), polyethylene glycol (200) diacrylate (PEG(200)DA), propoxylated neopentyl glycol diacrylate (NPG(PO)2DA).

[0049] Multifunctional (≥3) diluents:

[0050] Available types and models:

[0051] Trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA): Sartoma SR 238, propoxylated glycerol triacrylate (GPTA), ethoxylated trimethylolpropane triacrylate (TMP(EO)3TA), tri(2-hydroxyethyl)isocyanurate triacrylate.

[0052] The nano-titanium dioxide can be selected from commercially available dispersions or powders:

[0053] Surface-treated titanium dioxide: Ishihara, Japan: CR-60 (rutile type), CR-50.

[0054] Domestic suppliers such as Xuancheng Jingrui and Ningbo Xinyuan provided untreated nano titanium dioxide of corresponding specifications.

[0055] Surface-treated nano-titanium dioxide plays three key roles in this ink:

[0056] 1. As a dispersing agent: Nano-sized titanium dioxide particles can effectively intersect between carbon black agglomerates, preventing secondary agglomeration of carbon black through steric hindrance, resulting in more uniform and stable dispersion of carbon black pigment in the resin system. This directly leads to extremely high uniformity and smoothness of the coated film, eliminating defects caused by uneven dispersion, thereby improving the consistency of light blocking and product yield.

[0057] 2. As a curing accelerator: Experiments have shown that the surface-treated nano-titanium dioxide used in this invention, under UV irradiation, not only scatters some UV light but also significantly improves the efficiency of deep curing through some photocatalytic or energy transfer mechanism (the specific mechanism is not yet fully understood, but the effect is significant). This allows the ink to cure even at a thickness of 50-100 μm under conventional UV irradiation energy (e.g., 10000-20000 mJ / cm²). 2 Complete curing is achieved under these conditions, with no sticky residue at the bottom of the film.

[0058] 3. As an adhesion enhancer: The functional groups (such as siloxane groups) in the surface treatment agent can form strong chemical bonds at the interface between the ink and substrates such as glass and PC, greatly improving the adhesion of the ink to difficult-to-adhere substrates. Comparative experiments show that the ink with added titanium dioxide has a significantly better adhesion rating in the cross-cut adhesion test than the control sample without it.

[0059] The photoinitiator system may employ a pyrolysis-type (Type I) photoinitiator or an acylphosphooxide-based photoinitiator.

[0060] Cleavage type (Type I) photoinitiators:

[0061] Available types and models:

[0062] 2-Hydroxy-2-methyl-1-phenyl-1-propanone (1173 / HMPP): BASF Irgacure 1173.

[0063] 1-Hydroxycyclohexylphenyl ketone (184 / HCPK): BASF Irgacure 184.

[0064] 2-Methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (907): BASF Irgacure 907.

[0065] 2-Benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369): BASF Irgacure 369.

[0066] 2,2-Dimethoxy-1,2-diphenylethane-1-one (BDK / 651): BASF Irgacure 651.

[0067] Acylphosphine oxide photoinitiators:

[0068] Available types and models:

[0069] (2,4,6-Trimethylbenzoyl)diphenylphosphine oxide (TPO): BASF Irgacure TPO; Tianjin Jiuri TPO.

[0070] Phenylated bis(2,4,6-trimethylbenzoyl)phosphine oxide (819 / BAPO): BASF Irgacure 819; Tianjin Jiuri BAPO.

[0071] Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO): BASF Irgacure 819DW (water-dispersible).

[0072] Ethyl-2,4,6-trimethylbenzoylphenylphosphonate (TPO-L): BASF Irgacure TPO-L.

[0073] The photoinitiator system and nano-titanium dioxide produce a synergistic effect, thus jointly overcoming the problem of thick film curing.

[0074] The additives include dispersants, leveling agents, light stabilizers, defoamers, matting agents, and adhesion promoters.

[0075] Dispersant:

[0076] Examples of available commercial models:

[0077] BYK (BYK): BYK-163, BYK-2150, DISPERBYK-2012, BYK-110, BYK-180, BYK-2050.

[0078] EFKA: EFKA-4010, EFKA-4560, EFKA-4580, EFKA-4800.

[0079] TEGO: TEGO Dispers 655, TEGO Dispers 670.

[0080] BASF: PX 4700.

[0081] Leveling agent:

[0082] Examples of available commercial models:

[0083] BYK (BYK): BYK-331, BYK-307, BYK-333, BYK-378, BYK-361N.

[0084] TEGO: TEGO Glide 100, TEGO Glide 410, TEGO Glide440, TEGO Flow 300.

[0085] Evka (EFKA): EFKA-3232, EFKA-3883.

[0086] Light stabilizers:

[0087] Examples of available commercial models:

[0088] BASF:

[0089] Ultraviolet A (UVA) absorbers: Tinuvin 1130 (benzotriazole), Tinuvin 400 (benzotriazole), Tinuvin 928 (triazine).

[0090] Hindered amine light stabilizers (HALS): Tinuvin 123, Tinuvin 152, Tinuvin 292, Tinuvin 144.

[0091] Everlight: Eversorb 109 (UVA), Eversorb 353 (HALS).

[0092] Defoamer:

[0093] BYK Chemicals: BYK-052, BYK-077, BYK-088, BYK-1790.

[0094] Tego: TEGO Foamex 810, TEGO Foamex 1488.

[0095] Matte powder:

[0096] Grace: ED 30, ED 50.

[0097] Evonik: OK 412, HK 460.

[0098] Adhesion promoter (auxiliary):

[0099] Silane coupling agents: KH-550 (aminopropyl), KH-560 (epoxy), KH-570 (methacryloyloxy).

[0100] Commercial additive: DOW CORNING Z-6121 (silane).

[0101] Examples 1-2 and Comparative Examples 1-2 are given below:

[0102]

[0103]

[0104] The above ink was spin-coated onto a glass slide, with a dry film thickness controlled at 50 μm, and cured for 60 s at 365 nm and 300 mW. The test results are as follows:

[0105]

[0106] Experimental conclusion:

[0107] Comparative Example 1 (without TiO2): A 50μm thick film can be cured, but the adhesion is poor and the film surface is uneven.

[0108] Comparative Example 2 (without dispersant): Due to the agglomeration of nanoparticles and their poor compatibility with the system, compared with Comparative Example 1, the carbon black dispersion effect was even worse without a dispersant, and severe agglomeration occurred. Moreover, due to uneven dispersion, a uniform film layer was not formed on the substrate surface, resulting in an adhesion of 0B.

[0109] Examples 1 & 2: Thanks to the surface-treated nano-titanium dioxide, the dispersion of carbon black is greatly promoted, as is the curing efficiency of black ink. Unexpectedly, the light-blocking performance is also greatly improved, and it has good adhesion to the substrate.

[0110] The above ink was spin-coated onto a glass slide, with a dry film thickness controlled at 100 μm, and cured for 60 s at 365 nm and 300 mW. The test results are as follows:

[0111]

[0112] Experimental conclusion:

[0113] As shown in the table above, when the film thickness is increased to 100 μm, Comparative Example 1 (without TiO2) and Comparative Example 2 (without dispersant) can no longer be completely photocured; only the surface layer is cured, and the interior is not yet cured.

[0114] Examples 1 & 2: After adding nano-titanium dioxide, it still cured completely at a thickness of 100 μm, and the adhesion to the substrate remained at 5B. The light-shielding effect OD value could reach up to 4.8.

[0115] Examples 3-5 and Comparative Examples 3-4 are given below:

[0116]

[0117] The above ink was spin-coated onto a glass slide, with a dry film thickness controlled at 50 μm, and cured for 60 s at 365 nm and 300 mW. The test results are as follows:

[0118]

[0119]

[0120] Experimental conclusion:

[0121] The results of Implementation 3, Examples 4 and 5 show that the surface of the nano-titanium dioxide film with surface treatment is smoother and more uniform, has excellent adhesion to glass, and also improves the light-shielding ability.

[0122] Comparative Examples 3 and 4: After the addition of untreated titanium dioxide, the film surface was uneven and still had a light-blocking effect, but it also affected the curing efficiency, resulting in incomplete curing and no effect on promoting glass adhesion.

[0123] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high opacity, UV-curable black ink containing nanoscale titanium dioxide, characterized in that, By weight percentage, including the following components: 15-30% of ultraviolet light fixing resin, 15-25% of reactive diluent, 8-15% of carbon black, 10-20% of nano titanium dioxide, 2-6% of photoinitiator system, 1-3% of auxiliary agent, wherein the original particle size of the nano titanium dioxide is 10-20nm, and the surface thereof is treated by organosilane or titanate coupling agent.

2. The high opacity, UV-curable black ink containing nanoscale titanium dioxide according to claim 1, characterized in that: The ultraviolet light fixing resin is an oligomer containing unsaturated double bond, which can adopt one or more of epoxy acrylate (EA), polyurethane acrylate (PUA), polyester acrylate (PEA), pure acrylate resin, and adhesion promoting functional resin.

3. The high opacity, UV-curable black ink containing nanoscale titanium dioxide according to claim 1, characterized in that: The reactive diluent can adopt monofunctional diluent or bifunctional diluent or multifunctional diluent, the monofunctional diluent includes isobornyl acrylate (IBOA), lauryl acrylate (LA), methoxy polyethylene glycol acrylate (MPEGA), hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA) caprolactone acrylate (ICLA), tetrahydrofuran acrylate (THFA), phenol EO modified acrylate (PEA), the bifunctional diluent includes tripropyleneglycol diacrylate (TPGDA), neopentyl glycol diacrylate (NPGDA), hexanediol diacrylate (HDDA), tripropyleneglycol diacrylate (TPGDA), polyethylene glycol (200) diacrylate (PEG(200)DA), propoxylated neopentyl glycol diacrylate (NPG(PO)2DA), and the multifunctional diluent includes trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), propoxylated glyceryl triacrylate (GPTA), ethoxylated trimethylolpropane triacrylate (TMP(EO)3TA), tris(2-hydroxyethyl) isocyanurate triacrylate.

4. The high opacity, UV-curable black ink containing nanoscale titanium dioxide according to claim 1, characterized in that: The photoinitiator system can adopt cleavage type (type I) photoinitiator or acyl phosphine oxide type photoinitiator, the cleavage type (type I) photoinitiator includes 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173 / HMPP), 1-hydroxycyclohexyl phenyl ketone (184 / HCPK), 2-methyl-1-(4-methylthiophenyl)-2-morpholin-1-propanone (907), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl) butanone (369), 2,2-dimethoxy-1,2-diphenyl ethane-1-ketone (BDK / 651), and the acyl phosphine oxide type photoinitiator includes (2,4,6-trimethylbenzoyl) diphenyl phosphine oxide (TPO), phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide (819 / BAPO), bis(2,4,6-trimethylbenzoyl) phenyl phosphine oxide (BAPO), ethyl-2,4,6-trimethylbenzoyl phenyl phosphonate (TPO-L).

5. The high opacity, UV-curable black ink containing nanoscale titanium dioxide according to claim 1, characterized in that: The auxiliary agents include dispersants, leveling agents, light stabilizers, defoamers, matting powders, adhesion promoters.

Images